Climate, orography and scale controls on flood frequency in Triveneto (Italy)

NASA Astrophysics Data System (ADS)

Persiano, Simone; Castellarin, Attilio; Salinas, Jose Luis; Domeneghetti, Alessio; Brath, Armando

2016-05-01

The growing concern about the possible effects of climate change on flood frequency regime is leading Authorities to review previously proposed reference procedures for design-flood estimation, such as national flood frequency models. Our study focuses on Triveneto, a broad geographical region in North-eastern Italy. A reference procedure for design flood estimation in Triveneto is available from the Italian NCR research project "VA.PI.", which considered Triveneto as a single homogeneous region and developed a regional model using annual maximum series (AMS) of peak discharges that were collected up to the 1980s by the former Italian Hydrometeorological Service. We consider a very detailed AMS database that we recently compiled for 76 catchments located in Triveneto. All 76 study catchments are characterized in terms of several geomorphologic and climatic descriptors. The objective of our study is threefold: (1) to inspect climatic and scale controls on flood frequency regime; (2) to verify the possible presence of changes in flood frequency regime by looking at changes in time of regional L-moments of annual maximum floods; (3) to develop an updated reference procedure for design flood estimation in Triveneto by using a focused-pooling approach (i.e. Region of Influence, RoI). Our study leads to the following conclusions: (1) climatic and scale controls on flood frequency regime in Triveneto are similar to the controls that were recently found in Europe; (2) a single year characterized by extreme floods can have a remarkable influence on regional flood frequency models and analyses for detecting possible changes in flood frequency regime; (3) no significant change was detected in the flood frequency regime, yet an update of the existing reference procedure for design flood estimation is highly recommended and we propose the RoI approach for properly representing climate and scale controls on flood frequency in Triveneto, which cannot be regarded as a single homogeneous region.

Raising awareness of the importance of engineering protections against floods with "Flood-o-poly" v.2

NASA Astrophysics Data System (ADS)

Valyrakis, Manousos; Cheng, Ming

2017-04-01

This study presents the results of a survey focusing on the use of a new fit for purpose designed city in a sand-box model, namely "Flood-o-poly" version 2, which is building on the success of the previous model. "Flood-o-poly" has been successfully presented to thousands of students of all ages in the School of Engineering Open days (University of Glasgow), Widening Participation, Glasgow Science Festival, Glasgow Science Museum and Engineering Hydraulics classes and Design projects, over the last four years. The new design involves a new and extended 3D scaled model that accurately replicates the topography of a city along with its rivers, towards demonstrating the impacts of flooding (induced artificially in the scaled physical model via the use of small water pumps). "Flood-o-poly" is a highly visual and well popularized engineering outreach project (developed from the applicant at the University of Glasgow), which has already been extensively used to showcase the detrimental impacts of flooding, for both the natural ecosystems and the build infrastructure alike (see https://twitter.com/WaterEngLab/status/758270564561784832 on Twitter and https://youtu.be/H5oThT6QaTc on Youtube). This involves a highly interactive session where the students simulate the scenarios of "urbanization" (by placing more buildings on the flood-planes) and "climate change" where more extreme flow rates have to be routed through the river. The project demonstrates how this design can benefit the cohorts of the 3rd and 4rth year Civil Engineering undergraduate students, the students attending the School's Open days, Widening Participation Days, Glasgow Science Festival and Glasgow Science Museum events. "Flood-o-poly" focuses on personalizing the student experience with regard to flood impacts and promotes the need for resilient and sustainable flood protection designs. Further, using novel presentation and student-centered technologies, the students are given a truly unique experience and appreciate engineering principles and design approaches, as well as appreciate contemporary and optimal (under certain realistic constraints) flood protections that can be used to protect "Flood-o-poly" from extreme hydrologic events.

Probabilistic Design Storm Method for Improved Flood Estimation in Ungauged Catchments

NASA Astrophysics Data System (ADS)

Berk, Mario; Å pačková, Olga; Straub, Daniel

2017-12-01

The design storm approach with event-based rainfall-runoff models is a standard method for design flood estimation in ungauged catchments. The approach is conceptually simple and computationally inexpensive, but the underlying assumptions can lead to flawed design flood estimations. In particular, the implied average recurrence interval (ARI) neutrality between rainfall and runoff neglects uncertainty in other important parameters, leading to an underestimation of design floods. The selection of a single representative critical rainfall duration in the analysis leads to an additional underestimation of design floods. One way to overcome these nonconservative approximations is the use of a continuous rainfall-runoff model, which is associated with significant computational cost and requires rainfall input data that are often not readily available. As an alternative, we propose a novel Probabilistic Design Storm method that combines event-based flood modeling with basic probabilistic models and concepts from reliability analysis, in particular the First-Order Reliability Method (FORM). The proposed methodology overcomes the limitations of the standard design storm approach, while utilizing the same input information and models without excessive computational effort. Additionally, the Probabilistic Design Storm method allows deriving so-called design charts, which summarize representative design storm events (combinations of rainfall intensity and other relevant parameters) for floods with different return periods. These can be used to study the relationship between rainfall and runoff return periods. We demonstrate, investigate, and validate the method by means of an example catchment located in the Bavarian Pre-Alps, in combination with a simple hydrological model commonly used in practice.

Hydraulic analysis of Chenango River, Broome County, New York in relation to state highway plan

USGS Publications Warehouse

Dunn, Bernard

1981-01-01

Hydraulic analyses of the 50- and 100-year floods in a 3.2 mile reach of the Chenango River in the towns of Fenton and Chenango in New York were made to determine the effects of two alternative bridge designs on flood levels. Neither design would cause more than a 0.1-foot increase in water level of the 50-year flood nor more than a 0.2-foot increase in water level of the 100-year flood above levels that would occur during these floods under present channel conditions. The discharges used in the analyses were 55,200 cubic feet per second for the 50-year flood and 63,000 cubic feet per second for the 100-year flood. Mean flow velocities and water-surface elevations at 17 cross sections are given for both bridge designs and are compared with those that would occur under present conditions. (USGS)

Representative sets of design hydrographs for ungauged catchments: A regional approach using probabilistic region memberships

NASA Astrophysics Data System (ADS)

Brunner, Manuela Irene; Seibert, Jan; Favre, Anne-Catherine

2018-02-01

Traditional design flood estimation approaches have focused on peak discharges and have often neglected other hydrograph characteristics such as hydrograph volume and shape. Synthetic design hydrograph estimation procedures overcome this deficiency by jointly considering peak discharge, hydrograph volume, and shape. Such procedures have recently been extended to allow for the consideration of process variability within a catchment by a flood-type specific construction of design hydrographs. However, they depend on observed runoff time series and are not directly applicable in ungauged catchments where such series are not available. To obtain reliable flood estimates, there is a need for an approach that allows for the consideration of process variability in the construction of synthetic design hydrographs in ungauged catchments. In this study, we therefore propose an approach that combines a bivariate index flood approach with event-type specific synthetic design hydrograph construction. First, regions of similar flood reactivity are delineated and a classification rule that enables the assignment of ungauged catchments to one of these reactivity regions is established. Second, event-type specific synthetic design hydrographs are constructed using the pooled data divided by event type from the corresponding reactivity region in a bivariate index flood procedure. The approach was tested and validated on a dataset of 163 Swiss catchments. The results indicated that 1) random forest is a suitable classification model for the assignment of an ungauged catchment to one of the reactivity regions, 2) the combination of a bivariate index flood approach and event-type specific synthetic design hydrograph construction enables the consideration of event types in ungauged catchments, and 3) the use of probabilistic class memberships in regional synthetic design hydrograph construction helps to alleviate the problem of misclassification. Event-type specific synthetic design hydrograph sets enable the inclusion of process variability into design flood estimation and can be used as a compromise between single best estimate synthetic design hydrographs and continuous simulation studies.

Lagtime relations for urban streams in Georgia

USGS Publications Warehouse

Inman, Ernest J.

2000-01-01

Urban flood hydrographs are needed for the design of many highway drainage structures, embankments, and entrances to detention ponds. The three components that are needed to simulate urban flood hydrographs at ungaged sites are the design flood, the dimensionless hydrograph, and lagtime. The design flood and the dimensionless hydrograph have been presented in earlier studies for urban streams in Georgia. The objective of this study was to develop equations for estimating lagtime for urban streams in Georgia. Lagtimes were computed for 329 floods at 69 urban gaging stations in 11 cities in Georgia. These data were used to compute an average lagtime for each gaging station. Multiple regression analysis was then used to define relations between lagtime and certain physical basin characteristics, of which drainage area, slope, and impervious area were found to be significant. A qualitative variable was used to account for a geographical bias in flood-frequency region 4, a small area of southwestern Georgia. Information from this report can be used to simulate a flood hydrograph using a dimensionless hydrograph, the design flood, and the lagtime obtained from regression equations for any urban site with less than a 25-square-mile drainage area in Georgia.

33 CFR 203.15 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... of Congress. Flood control project: A project designed and constructed to have appreciable and... Washington, D.C. Hurricane/Shore Protection Project (HSPP). A flood control project designed and constructed... project, only those components that are necessary for the flood control function are considered eligible...

33 CFR 203.15 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... of Congress. Flood control project: A project designed and constructed to have appreciable and... Washington, D.C. Hurricane/Shore Protection Project (HSPP). A flood control project designed and constructed... project, only those components that are necessary for the flood control function are considered eligible...

33 CFR 203.15 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... of Congress. Flood control project: A project designed and constructed to have appreciable and... Washington, D.C. Hurricane/Shore Protection Project (HSPP). A flood control project designed and constructed... project, only those components that are necessary for the flood control function are considered eligible...

33 CFR 203.15 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... of Congress. Flood control project: A project designed and constructed to have appreciable and... Washington, D.C. Hurricane/Shore Protection Project (HSPP). A flood control project designed and constructed... project, only those components that are necessary for the flood control function are considered eligible...

Flood risk analysis for flood control and sediment transportation in sandy regions: A case study in the Loess Plateau, China

NASA Astrophysics Data System (ADS)

Guo, Aijun; Chang, Jianxia; Wang, Yimin; Huang, Qiang; Zhou, Shuai

2018-05-01

Traditional flood risk analysis focuses on the probability of flood events exceeding the design flood of downstream hydraulic structures while neglecting the influence of sedimentation in river channels on regional flood control systems. This work advances traditional flood risk analysis by proposing a univariate and copula-based bivariate hydrological risk framework which incorporates both flood control and sediment transport. In developing the framework, the conditional probabilities of different flood events under various extreme precipitation scenarios are estimated by exploiting the copula-based model. Moreover, a Monte Carlo-based algorithm is designed to quantify the sampling uncertainty associated with univariate and bivariate hydrological risk analyses. Two catchments located on the Loess plateau are selected as study regions: the upper catchments of the Xianyang and Huaxian stations (denoted as UCX and UCH, respectively). The univariate and bivariate return periods, risk and reliability in the context of uncertainty for the purposes of flood control and sediment transport are assessed for the study regions. The results indicate that sedimentation triggers higher risks of damaging the safety of local flood control systems compared with the event that AMF exceeds the design flood of downstream hydraulic structures in the UCX and UCH. Moreover, there is considerable sampling uncertainty affecting the univariate and bivariate hydrologic risk evaluation, which greatly challenges measures of future flood mitigation. In addition, results also confirm that the developed framework can estimate conditional probabilities associated with different flood events under various extreme precipitation scenarios aiming for flood control and sediment transport. The proposed hydrological risk framework offers a promising technical reference for flood risk analysis in sandy regions worldwide.

78 FR 14584 - Proposed Flood Hazard Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-06

...; Internal Agency Docket No. FEMA-B-1296] Proposed Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Notice. SUMMARY: Comments are requested on proposed flood hazard..., Special Flood Hazard Area (SFHA) boundary or zone designation, or regulatory floodway on the Flood...

Designing Flood Management Systems for Joint Economic and Ecological Robustness

NASA Astrophysics Data System (ADS)

Spence, C. M.; Grantham, T.; Brown, C. M.; Poff, N. L.

2015-12-01

Freshwater ecosystems across the United States are threatened by hydrologic change caused by water management operations and non-stationary climate trends. Nonstationary hydrology also threatens flood management systems' performance. Ecosystem managers and flood risk managers need tools to design systems that achieve flood risk reduction objectives while sustaining ecosystem functions and services in an uncertain hydrologic future. Robust optimization is used in water resources engineering to guide system design under climate change uncertainty. Using principles introduced by Eco-Engineering Decision Scaling (EEDS), we extend robust optimization techniques to design flood management systems that meet both economic and ecological goals simultaneously across a broad range of future climate conditions. We use three alternative robustness indices to identify flood risk management solutions that preserve critical ecosystem functions in a case study from the Iowa River, where recent severe flooding has tested the limits of the existing flood management system. We seek design modifications to the system that both reduce expected cost of flood damage while increasing ecologically beneficial inundation of riparian floodplains across a wide range of plausible climate futures. The first robustness index measures robustness as the fraction of potential climate scenarios in which both engineering and ecological performance goals are met, implicitly weighting each climate scenario equally. The second index builds on the first by using climate projections to weight each climate scenario, prioritizing acceptable performance in climate scenarios most consistent with climate projections. The last index measures robustness as mean performance across all climate scenarios, but penalizes scenarios with worse performance than average, rewarding consistency. Results stemming from alternate robustness indices reflect implicit assumptions about attitudes toward risk and reveal the tradeoffs between using structural and non-structural flood management strategies to ensure economic and ecological robustness.

Health Co-Benefits of Green Building Design Strategies and Community Resilience to Urban Flooding: A Systematic Review of the Evidence.

PubMed

Houghton, Adele; Castillo-Salgado, Carlos

2017-12-06

Climate change is increasingly exacerbating existing population health hazards, as well as resulting in new negative health effects. Flooding is one particularly deadly example of its amplifying and expanding effect on public health. This systematic review considered evidence linking green building strategies in the Leadership in Energy and Environmental Design ® (LEED) Rating System with the potential to reduce negative health outcomes following exposure to urban flooding events. Queries evaluated links between LEED credit requirements and risk of exposure to urban flooding, environmental determinants of health, co-benefits to public health outcomes, and co-benefits to built environment outcomes. Public health co-benefits to leveraging green building design to enhance flooding resilience included: improving the interface between humans and wildlife and reducing the risk of waterborne disease, flood-related morbidity and mortality, and psychological harm. We conclude that collaborations among the public health, climate change, civil society, and green building sectors to enhance community resilience to urban flooding could benefit population health.

Next-Generation Intensity-Duration-Frequency Curves for Hydrologic Design in Snow-Dominated Environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Hongxiang; Sun, Ning; Wigmosta, Mark

Precipitation-based intensity-duration-frequency (PREC-IDF) curves are a standard tool used to derive design floods for hydraulic infrastructure worldwide. In snow-dominated regions where a large percentage of flood events are caused by snowmelt and rain-on-snow events, the PREC-IDF design approach can lead to substantial underestimation/overestimation of design floods and associated infrastructure. In this study, next-generation IDF (NG-IDF) curves, which characterize the actual water reaching the land surface, are introduced into the design process to improve hydrologic design. The authors compared peak design flood estimates from the National Resource Conservation Service TR-55 hydrologic model driven by NG-IDF and PREC-IDF curves at 399 Snowpackmore » Telemetry (SNOTEL) stations across the western United States, all of which had at least 30 years of high-quality records. They found that about 72% of the stations in the western United States showed the potential for underdesign, for which the PREC-IDF curves underestimated peak design floods by as much as 324%. These results demonstrated the need to update the use of PREC-IDF curves to the use of NG-IDF curves for hydrologic design in snow-dominated regions.« less

Next-Generation Intensity‐Duration‐Frequency Curves for Hydrologic Design in Snow-Dominated Environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Hongxiang; Sun, Ning; Wigmosta, Mark S.

Precipitation-based intensity-duration-frequency (PREC-IDF) curves are a standard tool used to derive design floods for hydraulic infrastructure worldwide. In snow-dominated regions where a large percentage of flood events are caused by snowmelt and rain-on-snow events, the PREC-IDF design approach can lead to substantial underestimation/overestimation of design floods and associated infrastructure. In this study, next-generation IDF (NG-IDF) curves, which characterize the actual water reaching the land surface, are introduced into the design process to improve hydrologic design. The authors compared peak design flood estimates from the National Resource Conservation Service TR-55 hydrologic model driven by NG-IDF and PREC-IDF curves at 399 Snowpackmore » Telemetry (SNOTEL) stations across the western United States, all of which had at least 30 years of high-quality records. They found that about 72% of the stations in the western United States showed the potential for underdesign, for which the PREC-IDF curves underestimated peak design floods by as much as 324%. These results demonstrated the need to update the use of PREC-IDF curves to the use of NG-IDF curves for hydrologic design in snow-dominated regions.« less

23 CFR 650.117 - Content of design studies.

Code of Federal Regulations, 2013 CFR

2013-04-01

... BRIDGES, STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains § 650... probability of exceedance and, at appropriate locations, the water surface elevations associated with the overtopping flood or the flood of § 650.115(a)(1)(ii), and (2) The magnitude and water surface elevation of...

23 CFR 650.117 - Content of design studies.

Code of Federal Regulations, 2014 CFR

2014-04-01

... BRIDGES, STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains § 650... probability of exceedance and, at appropriate locations, the water surface elevations associated with the overtopping flood or the flood of § 650.115(a)(1)(ii), and (2) The magnitude and water surface elevation of...

23 CFR 650.117 - Content of design studies.

Code of Federal Regulations, 2012 CFR

2012-04-01

... BRIDGES, STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains § 650... probability of exceedance and, at appropriate locations, the water surface elevations associated with the overtopping flood or the flood of § 650.115(a)(1)(ii), and (2) The magnitude and water surface elevation of...

23 CFR 650.117 - Content of design studies.

Code of Federal Regulations, 2011 CFR

2011-04-01

... BRIDGES, STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains § 650... probability of exceedance and, at appropriate locations, the water surface elevations associated with the overtopping flood or the flood of § 650.115(a)(1)(ii), and (2) The magnitude and water surface elevation of...

23 CFR 650.117 - Content of design studies.

Code of Federal Regulations, 2010 CFR

2010-04-01

... BRIDGES, STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains § 650... probability of exceedance and, at appropriate locations, the water surface elevations associated with the overtopping flood or the flood of § 650.115(a)(1)(ii), and (2) The magnitude and water surface elevation of...

Magnitude and frequency of summer floods in western New Mexico and eastern Arizona

USGS Publications Warehouse

Kennon, F.W.

1955-01-01

Numerous small reservoirs and occasional water-spreading structures are being built on the ephemeral streams draining the public and Indian lands of the Southwest as part of the Soil and Moisture Conservation Program of the Bureau of Land Management and Bureau of Indian Affairs.  Economic design of these structures requires some knowledge of the flood rates and volumes.  Information concerning flood frequencies on areas less than 100 square miles is deficient throughout the country, particularly on intermittent streams of the Southwest.  Design engineers require a knowledge of the frequency and magnitude of flood volumes for the planning of adequate reservoir capacities and a knowledge of frequency and magnitude of flood peaks for spillway design.  Hence, this study deals with both flood volumes and peaks, the same statistical methods being used to develop frequency curves for each.

The Complex Relationship Between Heavy Storms and Floods: Implication on Stormwater Drainage design and Management

NASA Astrophysics Data System (ADS)

Demissie, Y.; Mortuza, M. R.; Moges, E.; Yan, E.; Li, H. Y.

2017-12-01

Due to the lack of historical and future streamflow data for flood frequency analysis at or near most drainage sites, it is a common practice to directly estimate the design flood (maximum discharge or volume of stream for a given return period) based on storm frequency analysis and the resulted Intensity-Duration-Frequency (IDF) curves. Such analysis assumes a direct relationship between storms and floods with, for example, the 10-year rainfall expected to produce the 10-year flood. However, in reality, a storm is just one factor among the many other hydrological and metrological factors that can affect the peak flow and hydrograph. Consequently, a heavy storm does not necessarily always lead to flooding or a flood events with the same frequency. This is evident by the observed difference in the seasonality of heavy storms and floods in most regions. In order to understand site specific causal-effect relationship between heavy storms and floods and improve the flood analysis for stormwater drainage design and management, we have examined the contributions of various factors that affect floods using statistical and information theory methods. Based on the identified dominant causal-effect relationships, hydrologic and probability analyses were conducted to develop the runoff IDF curves taking into consideration the snowmelt and rain-on-snow effect, the difference in the storm and flood seasonality, soil moisture conditions, and catchment potential for flash and riverine flooding. The approach was demonstrated using data from military installations located in different parts of the United States. The accuracy of the flood frequency analysis and the resulted runoff IDF curves were evaluated based on the runoff IDF curves developed from streamflow measurements.

Quantification of increased flood risk due to global climate change for urban river management planning.

PubMed

Morita, M

2011-01-01

Global climate change is expected to affect future rainfall patterns. These changes should be taken into account when assessing future flooding risks. This study presents a method for quantifying the increase in flood risk caused by global climate change for use in urban flood risk management. Flood risk in this context is defined as the product of flood damage potential and the probability of its occurrence. The study uses a geographic information system-based flood damage prediction model to calculate the flood damage caused by design storms with different return periods. Estimation of the monetary damages these storms produce and their return periods are precursors to flood risk calculations. The design storms are developed from modified intensity-duration-frequency relationships generated by simulations of global climate change scenarios (e.g. CGCM2A2). The risk assessment method is applied to the Kanda River basin in Tokyo, Japan. The assessment provides insights not only into the flood risk cost increase due to global warming, and the impact that increase may have on flood control infrastructure planning.

Magnitude and frequency of floods in Nebraska

USGS Publications Warehouse

Beckman, Emil W.

1976-01-01

Observed maximum flood peaks at 303 gaging stations with 13 or more years of record and significant peaks at 57 short-term stations and 31 miscellaneous sites are useful in designing flood-control works for maximum safety from flood damage. Comparison is made with maximum observed floods in the United States.

Numerical simulation of flood barriers

NASA Astrophysics Data System (ADS)

Srb, Pavel; Petrů, Michal; Kulhavý, Petr

This paper deals with testing and numerical simulating of flood barriers. The Czech Republic has been hit by several very devastating floods in past years. These floods caused several dozens of causalities and property damage reached billions of Euros. The development of flood measures is very important, especially for the reduction the number of casualties and the amount of property damage. The aim of flood control measures is the detention of water outside populated areas and drainage of water from populated areas as soon as possible. For new flood barrier design it is very important to know its behaviour in case of a real flood. During the development of the barrier several standardized tests have to be carried out. Based on the results from these tests numerical simulation was compiled using Abaqus software and some analyses were carried out. Based on these numerical simulations it will be possible to predict the behaviour of barriers and thus improve their design.

Design of flood early warning system with wifi network based on smartphone

NASA Astrophysics Data System (ADS)

Supani, Ahyar; Andriani, Yuli; Taqwa, Ahmad

2017-11-01

Today, the development using internet of things enables activities surrounding us to be monitored, controlled, predicted and calculated remotely through connections to the internet network such as monitoring activities of long-distance flood warning with information technology. Applying an information technology in the field of flood early warning has been developed in the world, either connected to internet network or not. The internet network that has been done in this paper is the design of WiFi network to access data of rainfall, water level and flood status at any time with a smartphone coming from flood early warning system. The results obtained when test of data accessing with smartphone are in form of rainfall and water level graphs against time and flood status indicators consisting of 3 flood states: Standby 2, Standby 1 and Flood. It is concluded that data are from flood early warning system has been able to accessed and displayed on smartphone via WiFi network in any time and real time.

Floods in the Raccoon River basin, Iowa

USGS Publications Warehouse

Heinitz, Albert J.

1980-01-01

Evaluation of flood hazards, and the planning, design, and operation of various facilities on flood plains requires information on floods. This report provides information on flood stages and discharges, flood magnitude and frequency, bench mark data, and flood profiles for the Raccoon River and some of its tributaries. Ir covers the Raccoon River, the North Raccoon River to the northern boundary of Sac County and the lower reaches of the Middle and South Raccoon Rivers.

12 CFR 22.7 - Forced placement of flood insurance.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Forced placement of flood insurance. 22.7... HAVING SPECIAL FLOOD HAZARDS § 22.7 Forced placement of flood insurance. If a bank, or a servicer acting... or mobile home and any personal property securing the designated loan is not covered by flood...

Health Co-Benefits of Green Building Design Strategies and Community Resilience to Urban Flooding: A Systematic Review of the Evidence

PubMed Central

Castillo-Salgado, Carlos

2017-01-01

Climate change is increasingly exacerbating existing population health hazards, as well as resulting in new negative health effects. Flooding is one particularly deadly example of its amplifying and expanding effect on public health. This systematic review considered evidence linking green building strategies in the Leadership in Energy and Environmental Design® (LEED) Rating System with the potential to reduce negative health outcomes following exposure to urban flooding events. Queries evaluated links between LEED credit requirements and risk of exposure to urban flooding, environmental determinants of health, co-benefits to public health outcomes, and co-benefits to built environment outcomes. Public health co-benefits to leveraging green building design to enhance flooding resilience included: improving the interface between humans and wildlife and reducing the risk of waterborne disease, flood-related morbidity and mortality, and psychological harm. We conclude that collaborations among the public health, climate change, civil society, and green building sectors to enhance community resilience to urban flooding could benefit population health. PMID:29210981

Technical note: Design flood under hydrological uncertainty

NASA Astrophysics Data System (ADS)

Botto, Anna; Ganora, Daniele; Claps, Pierluigi; Laio, Francesco

2017-07-01

Planning and verification of hydraulic infrastructures require a design estimate of hydrologic variables, usually provided by frequency analysis, and neglecting hydrologic uncertainty. However, when hydrologic uncertainty is accounted for, the design flood value for a specific return period is no longer a unique value, but is represented by a distribution of values. As a consequence, the design flood is no longer univocally defined, making the design process undetermined. The Uncertainty Compliant Design Flood Estimation (UNCODE) procedure is a novel approach that, starting from a range of possible design flood estimates obtained in uncertain conditions, converges to a single design value. This is obtained through a cost-benefit criterion with additional constraints that is numerically solved in a simulation framework. This paper contributes to promoting a practical use of the UNCODE procedure without resorting to numerical computation. A modified procedure is proposed by using a correction coefficient that modifies the standard (i.e., uncertainty-free) design value on the basis of sample length and return period only. The procedure is robust and parsimonious, as it does not require additional parameters with respect to the traditional uncertainty-free analysis. Simple equations to compute the correction term are provided for a number of probability distributions commonly used to represent the flood frequency curve. The UNCODE procedure, when coupled with this simple correction factor, provides a robust way to manage the hydrologic uncertainty and to go beyond the use of traditional safety factors. With all the other parameters being equal, an increase in the sample length reduces the correction factor, and thus the construction costs, while still keeping the same safety level.

Development of an anti-flood board to protect the interiors and exteriors of the infrastructure

NASA Astrophysics Data System (ADS)

Petru, Michal; Srb, Pavel; Sevcik, Ladislav; Martinec, Tomas; Kulhavy, Petr

2018-06-01

This article deals with the development of an anti-flood board to protect the interior and exterior of various infrastructures, such a houses, cottages or industrial buildings. It was designed prototypes and assembled numerical simulations. In Central Europe and in particular in the Czech Republic, floods are an integral part of the natural water cycle and cause great loss of life and great property damage. The development of new types of mobile anti-flood boards is very important as the design solution is developed for flood protection with regard to minimizing weight, cost of production, easy manipulation, simplicity and speed of installation.

46 CFR 171.017 - One and two compartment standards of flooding.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false One and two compartment standards of flooding. 171.017... standards of flooding. (a) One compartment standard of flooding. A vessel is designed to a one compartment standard of flooding if the margin line is not submerged when the total buoyancy between each set of two...

46 CFR 171.017 - One and two compartment standards of flooding.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false One and two compartment standards of flooding. 171.017... standards of flooding. (a) One compartment standard of flooding. A vessel is designed to a one compartment standard of flooding if the margin line is not submerged when the total buoyancy between each set of two...

46 CFR 171.017 - One and two compartment standards of flooding.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 7 2012-10-01 2012-10-01 false One and two compartment standards of flooding. 171.017... standards of flooding. (a) One compartment standard of flooding. A vessel is designed to a one compartment standard of flooding if the margin line is not submerged when the total buoyancy between each set of two...

46 CFR 171.017 - One and two compartment standards of flooding.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 7 2014-10-01 2014-10-01 false One and two compartment standards of flooding. 171.017... standards of flooding. (a) One compartment standard of flooding. A vessel is designed to a one compartment standard of flooding if the margin line is not submerged when the total buoyancy between each set of two...

46 CFR 171.017 - One and two compartment standards of flooding.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false One and two compartment standards of flooding. 171.017... standards of flooding. (a) One compartment standard of flooding. A vessel is designed to a one compartment standard of flooding if the margin line is not submerged when the total buoyancy between each set of two...

Estimation of design floods in ungauged catchments using a regional index flood method. A case study of Lake Victoria Basin in Kenya

NASA Astrophysics Data System (ADS)

Nobert, Joel; Mugo, Margaret; Gadain, Hussein

Reliable estimation of flood magnitudes corresponding to required return periods, vital for structural design purposes, is impacted by lack of hydrological data in the study area of Lake Victoria Basin in Kenya. Use of regional information, derived from data at gauged sites and regionalized for use at any location within a homogenous region, would improve the reliability of the design flood estimation. Therefore, the regional index flood method has been applied. Based on data from 14 gauged sites, a delineation of the basin into two homogenous regions was achieved using elevation variation (90-m DEM), spatial annual rainfall pattern and Principal Component Analysis of seasonal rainfall patterns (from 94 rainfall stations). At site annual maximum series were modelled using the Log normal (LN) (3P), Log Logistic Distribution (LLG), Generalized Extreme Value (GEV) and Log Pearson Type 3 (LP3) distributions. The parameters of the distributions were estimated using the method of probability weighted moments. Goodness of fit tests were applied and the GEV was identified as the most appropriate model for each site. Based on the GEV model, flood quantiles were estimated and regional frequency curves derived from the averaged at site growth curves. Using the least squares regression method, relationships were developed between the index flood, which is defined as the Mean Annual Flood (MAF) and catchment characteristics. The relationships indicated area, mean annual rainfall and altitude were the three significant variables that greatly influence the index flood. Thereafter, estimates of flood magnitudes in ungauged catchments within a homogenous region were estimated from the derived equations for index flood and quantiles from the regional curves. These estimates will improve flood risk estimation and to support water management and engineering decisions and actions.

Development of cost-effective surfactant flooding technology. Quarterly report, January 1, 1994--March 31, 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pope, G.A.; Sepehrnoori, K.

1994-09-01

The objective of this research is to develop cost-effective surfactant flooding technology by using surfactant simulation studies to evaluate and optimize alternative design strategies taking into account reservoir characteristics, process chemistry, and process design options such as horizontal wells. Task 1 is the development of an improved numerical method for our simulator that will enable us to solve a wider class of these difficult simulation problems accurately and affordably. Task 2 is the application of this simulator to the optimization of surfactant flooding to reduce its risk and cost. The goal of Task 2 is to understand and generalize themore » impact of both process and reservoir characteristics on the optimal design of surfactant flooding. We have studied the effect of process parameters such as salinity gradient, surfactant adsorption, surfactant concentration, surfactant slug size, pH, polymer concentration and well constraints on surfactant floods. In this report, we show three dimensional field scale simulation results to illustrate the impact of one important design parameter, the salinity gradient. Although the use of a salinity gradient to improve the efficiency and robustness of surfactant flooding has been studied and applied for many years, this is the first time that we have evaluated it using stochastic simulations rather than simulations using the traditional layered reservoir description. The surfactant flooding simulations were performed using The University of Texas chemical flooding simulator called UTCHEM.« less

Impact of stream restoration on flood waves

NASA Astrophysics Data System (ADS)

Sholtes, J.; Doyle, M.

2008-12-01

Restoration of channelized or incised streams has the potential to reduce downstream flooding via storing and dissipating the energy of flood waves. Restoration design elements such as restoring meanders, reducing slope, restoring floodplain connectivity, re-introducing in-channel woody debris, and re-vegetating banks and the floodplain have the capacity to attenuate flood waves via energy dissipation and channel and floodplain storage. Flood discharge hydrographs measured up and downstream of several restored reaches of varying stream order and located in both urban and rural catchments are coupled with direct measurements of stream roughness at various stages to directly measure changes to peak discharge, flood wave celerity, and dispersion. A one-dimensional unsteady flow routing model, HEC-RAS, is calibrated and used to compare attenuation characteristics between pre and post restoration conditions. Modeled sensitivity results indicate that a restoration project placed on a smaller order stream demonstrates the highest relative reduction in peak discharge of routed flood waves compared to one of equal length on a higher order stream. Reductions in bed slope, extensions in channel length, and increases in channel and floodplain roughness follow restoration placement with the watershed in relative importance. By better understanding how design, scale, and location of restored reaches within a catchment hydraulically impact flood flows, this study contributes both to restoration design and site decision making. It also quantifies the effect of reach scale stream restoration on flood wave attenuation.

78 FR 21136 - Changes in Flood Hazard Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-09

... zone designations, or the regulatory floodway (hereinafter referred to as flood hazard determinations), as shown on the Flood Insurance Rate Maps (FIRMs), and where applicable, in the supporting Flood... appeals to the Chief Executive Officer of the community as listed in the table below. FOR FURTHER...

78 FR 35300 - Changes in Flood Hazard Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-12

... zone designations, or the regulatory floodway (hereinafter referred to as flood hazard determinations), as shown on the Flood Insurance Rate Maps (FIRMs), and where applicable, in the supporting Flood... appeals to the Chief Executive Officer of the community as listed in the table below. FOR FURTHER...

Extent and frequency of floods on the Schuylkill River near Phoenixville and Pottstown, Pennsylvania

USGS Publications Warehouse

Busch, William F.; Shaw, Lewis C.

1973-01-01

Knowledge of the frequency and extent of flooding is an important requirement for the design of all works of man bordering or encroaching on flood plains. The proper design of bridges, culverts, dams, highways, levees, reservoirs, sewage-disposal systems, waterworks and all structures on the flood plains of streams requires careful consideration of flood hazards. -1- By use of relations presented in this report, the extent, depth, and frequency of flooding can be estimated for any site along the reach of the Schuylkill River from Oaks to Pottstown. These flood data are presented so that regulatory agencies, organizations, and individuals may have a technical basis for making decisions on the use of flood-prone areas. The Delaware River Basin Commission and the U. S. Geological Survey regard this program of flood-plain-inundation studies as a positive step toward flood-damage prevention. Flood-plaininundation studies are a prerequisite to flood-plain management which may include a mixture of flood-control structures and/or land-use regulations. Both physical works and flood-plain regulations are included in the Comprehensive Plan for development of the Delaware River basin, of which the Schuylkill River is a part. Recommendations for land use, or suggestions for limitations of land use, are not made herein. Other reports on use and regulation of land in flood-prone areas are available (Dola, 1961; White, 1961; American Society of Civil Engineers Task Force on Flood Plain Regulations, 1962; and Goddard, 1963). The primary responsibility for planning for optimum land use in the flood plain and the implementation of flood-plain zoning or other regulations to achieve such optimum use rests with State, and local interests.

The dichotomous response of flood and storm extremes to rising global temperatures

NASA Astrophysics Data System (ADS)

Sharma, A.; Wasko, C.

2017-12-01

Rising temperature have resulted in increases in short-duration rainfall extremes across the world. Additionally it has been shown (doi:10.1038/ngeo2456) that storms will intensify, causing derived flood peaks to rise even more. This leads us to speculate that flood peaks will increase as a result, complying with the storyline presented in past IPCC reports. This talk, however, shows that changes in flood extremes are much more complex. Using global data on extreme flow events, the study conclusively shows that while the very extreme floods may be rising as a result of storm intensification, the more frequent flood events are decreasing in magnitude. The study argues that changes in the magnitude of floods are a function of changes in storm patterns and as well as pre-storm or antecedent conditions. It goes on to show that while changes in storms dominate for the most extreme events and over smaller, more urbanised catchments, changes in pre-storm conditions are the driving factor in modulating flood peaks in large rural catchments. The study concludes by providing recommendations on how future flood design should proceed, arguing that current practices (or using a design storm to estimate floods) are flawed and need changing.

Modeling Compound Flood Hazards in Coastal Embayments

NASA Astrophysics Data System (ADS)

Moftakhari, H.; Schubert, J. E.; AghaKouchak, A.; Luke, A.; Matthew, R.; Sanders, B. F.

2017-12-01

Coastal cities around the world are built on lowland topography adjacent to coastal embayments and river estuaries, where multiple factors threaten increasing flood hazards (e.g. sea level rise and river flooding). Quantitative risk assessment is required for administration of flood insurance programs and the design of cost-effective flood risk reduction measures. This demands a characterization of extreme water levels such as 100 and 500 year return period events. Furthermore, hydrodynamic flood models are routinely used to characterize localized flood level intensities (i.e., local depth and velocity) based on boundary forcing sampled from extreme value distributions. For example, extreme flood discharges in the U.S. are estimated from measured flood peaks using the Log-Pearson Type III distribution. However, configuring hydrodynamic models for coastal embayments is challenging because of compound extreme flood events: events caused by a combination of extreme sea levels, extreme river discharges, and possibly other factors such as extreme waves and precipitation causing pluvial flooding in urban developments. Here, we present an approach for flood risk assessment that coordinates multivariate extreme analysis with hydrodynamic modeling of coastal embayments. First, we evaluate the significance of correlation structure between terrestrial freshwater inflow and oceanic variables; second, this correlation structure is described using copula functions in unit joint probability domain; and third, we choose a series of compound design scenarios for hydrodynamic modeling based on their occurrence likelihood. The design scenarios include the most likely compound event (with the highest joint probability density), preferred marginal scenario and reproduced time series of ensembles based on Monte Carlo sampling of bivariate hazard domain. The comparison between resulting extreme water dynamics under the compound hazard scenarios explained above provides an insight to the strengths/weaknesses of each approach and helps modelers choose the appropriate scenario that best fit to the needs of their project. The proposed risk assessment approach can help flood hazard modeling practitioners achieve a more reliable estimate of risk, by cautiously reducing the dimensionality of the hazard analysis.

U.S./China Bilateral Symposium on Extraordinary Floods

NASA Astrophysics Data System (ADS)

Kirby, W.

Accurate appraisal of the risk of extreme floods has long been of concern to hydrologists and water resources managers in both the United States and China. In order to exchange information, assess current developments, and discuss further needs in extreme flood analysis, the U.S. Geological Survey (USGS) and the Bureau of Hydrology of the Ministry of Water Resources and Electric Power of the People's Republic of China (PRC) held the Bilateral Symposium on the Analysis of Extraordinary Flood Events, October 14-18, 1985, in Nanjing, China. Co-convenors of the symposium were Marshall E. Moss (USGS) and Hua Shiqian (Nanjing Research Institute of Hydrology). Liang Ruiju (East China Technical University of Water Resources) was executive secretary of the organizing committee. Participants included 23 U.S. delegates, 36 Chinese delegates, and five guests from other countries. Of the U.S. delegates, 13 were from federal agencies, seven were from universities, and three were private consultants. The U.S. National Science Foundation gave financial support to the nonfederal U.S. delegates. Major topics covered in the 52 papers presented included detection of historical floods and evaluation of the uncertainties in their peak discharges and times of occurrence,frequency analysis and design flood determination in the presence of extraordinary floods and historic floods, anduse of storm data in determining design storms and design floods, The symposium was followed by a 6-day study tour in central China, during which laboratories, field activities, and offices of various water resources agencies were visited and sites of documented historic floods on the Yangtze River and its tributaries were examined.

Why continuous simulation? The role of antecedent moisture in design flood estimation

NASA Astrophysics Data System (ADS)

Pathiraja, S.; Westra, S.; Sharma, A.

2012-06-01

Continuous simulation for design flood estimation is increasingly becoming a viable alternative to traditional event-based methods. The advantage of continuous simulation approaches is that the catchment moisture state prior to the flood-producing rainfall event is implicitly incorporated within the modeling framework, provided the model has been calibrated and validated to produce reasonable simulations. This contrasts with event-based models in which both information about the expected sequence of rainfall and evaporation preceding the flood-producing rainfall event, as well as catchment storage and infiltration properties, are commonly pooled together into a single set of "loss" parameters which require adjustment through the process of calibration. To identify the importance of accounting for antecedent moisture in flood modeling, this paper uses a continuous rainfall-runoff model calibrated to 45 catchments in the Murray-Darling Basin in Australia. Flood peaks derived using the historical daily rainfall record are compared with those derived using resampled daily rainfall, for which the sequencing of wet and dry days preceding the heavy rainfall event is removed. The analysis shows that there is a consistent underestimation of the design flood events when antecedent moisture is not properly simulated, which can be as much as 30% when only 1 or 2 days of antecedent rainfall are considered, compared to 5% when this is extended to 60 days of prior rainfall. These results show that, in general, it is necessary to consider both short-term memory in rainfall associated with synoptic scale dependence, as well as longer-term memory at seasonal or longer time scale variability in order to obtain accurate design flood estimates.

Flood Catastrophe Model for Designing Optimal Flood Insurance Program: Estimating Location-Specific Premiums in the Netherlands.

PubMed

Ermolieva, T; Filatova, T; Ermoliev, Y; Obersteiner, M; de Bruijn, K M; Jeuken, A

2017-01-01

As flood risks grow worldwide, a well-designed insurance program engaging various stakeholders becomes a vital instrument in flood risk management. The main challenge concerns the applicability of standard approaches for calculating insurance premiums of rare catastrophic losses. This article focuses on the design of a flood-loss-sharing program involving private insurance based on location-specific exposures. The analysis is guided by a developed integrated catastrophe risk management (ICRM) model consisting of a GIS-based flood model and a stochastic optimization procedure with respect to location-specific risk exposures. To achieve the stability and robustness of the program towards floods with various recurrences, the ICRM uses stochastic optimization procedure, which relies on quantile-related risk functions of a systemic insolvency involving overpayments and underpayments of the stakeholders. Two alternative ways of calculating insurance premiums are compared: the robust derived with the ICRM and the traditional average annual loss approach. The applicability of the proposed model is illustrated in a case study of a Rotterdam area outside the main flood protection system in the Netherlands. Our numerical experiments demonstrate essential advantages of the robust premiums, namely, that they: (1) guarantee the program's solvency under all relevant flood scenarios rather than one average event; (2) establish a tradeoff between the security of the program and the welfare of locations; and (3) decrease the need for other risk transfer and risk reduction measures. © 2016 Society for Risk Analysis.

Bivariate analysis of floods in climate impact assessments.

PubMed

Brunner, Manuela Irene; Sikorska, Anna E; Seibert, Jan

2018-03-01

Climate impact studies regarding floods usually focus on peak discharges and a bivariate assessment of peak discharges and hydrograph volumes is not commonly included. A joint consideration of peak discharges and hydrograph volumes, however, is crucial when assessing flood risks for current and future climate conditions. Here, we present a methodology to develop synthetic design hydrographs for future climate conditions that jointly consider peak discharges and hydrograph volumes. First, change factors are derived based on a regional climate model and are applied to observed precipitation and temperature time series. Second, the modified time series are fed into a calibrated hydrological model to simulate runoff time series for future conditions. Third, these time series are used to construct synthetic design hydrographs. The bivariate flood frequency analysis used in the construction of synthetic design hydrographs takes into account the dependence between peak discharges and hydrograph volumes, and represents the shape of the hydrograph. The latter is modeled using a probability density function while the dependence between the design variables peak discharge and hydrograph volume is modeled using a copula. We applied this approach to a set of eight mountainous catchments in Switzerland to construct catchment-specific and season-specific design hydrographs for a control and three scenario climates. Our work demonstrates that projected climate changes have an impact not only on peak discharges but also on hydrograph volumes and on hydrograph shapes both at an annual and at a seasonal scale. These changes are not necessarily proportional which implies that climate impact assessments on future floods should consider more flood characteristics than just flood peaks. Copyright © 2017. Published by Elsevier B.V.

Regional flood frequency analysis in Triveneto (Italy): climate and scale controls

NASA Astrophysics Data System (ADS)

Persiano, Simone; Castellarin, Attilio; Domeneghetti, Alessio; Brath, Armando

2016-04-01

The growing concern about the possible effects of climate change on flood frequency regime is leading Authorities to review previously proposed procedures for design-flood estimation, such as national regionalization approaches. Our study focuses on the Triveneto region, a broad geographical area in North-eastern Italy consisting of the administrative regions of Trentino-Alto Adige, Veneto and Friuli-Venezia Giulia. A reference procedure for design flood estimation in Triveneto is available from the Italian NCR research project "VA.PI.", which developed a regional model using annual maximum series (AMS) of peak discharges that were collected up to the 80s by the former Italian Hydrometeorological Service. We consider a very detailed AMS database that we recently compiled for ~80 catchments located in Triveneto. Our dataset includes the historical data mentioned above, together with more recent data obtained from Regional Services and annual maximum peak streamflows extracted from inflow series to artificial reservoirs and provided by dam managers. All ~80 study catchments are characterized in terms of several geomorphologic and climatic descriptors. The main objectives of our study are: (1) to check whether climatic and scale controls on flood frequency regime in Triveneto are similar to the controls that were recently found in Europe; (2) to verify the possible presence of trends as well as abrupt changes in the intensity and frequency of flood extremes by looking at changes in time of regional L-moments of annual maximum floods; (3) to assess the reliability and representativeness of the reference procedure for design flood estimation relative to flood data that were not included in the VA.PI. dataset (i.e. more recent data collected after the 80s and historical data provided by dam managers); (4) to develop an updated reference procedure for design flood estimation in Triveneto by using a focused-pooling approach (i.e. Region of Influence, RoI).

The use of novel wooden structures to manage flooding and coarse sediment problems in responsive upland headwater catchments

NASA Astrophysics Data System (ADS)

Wilkinson, Mark; Addy, Steve; Ghimire, Sohan; Watson, Helen; Stutter, Marc

2014-05-01

Over the past decade economic losses from floods have greatly increased, with sediment related impacts as a key feature of such events. Impacts include changes in river channel course, scour of river banks, sedimentation of infrastructure (e.g. bridges), and deposition of sand and gravel on farmland. Sediment deposition can in turn reduce conveyance capacity and lead to further increased flood risk. The EU Water Framework Directive and Floods Directive highlights that sustainable approaches to flood risk reduction should be used alongside and, where possible, replace traditional structural flood defences and activities that address sediment problems. Natural Flood Management(NFM) is promoted as a method that can reduce flood risk and manage sediment by incorporating natural hydrological and morphological processes. As such, NFM measures are designed to use these fluvial processes to manage the sources and pathways of flood waters and sediments. Techniques include the restoration, enhancement and alteration of natural features and characteristics, but exclude traditional flood defence engineering that works against or disrupts these natural processes. Here we aim to assess the effectiveness of novel flood mitigation measures for reducing flood risk and capturing coarse sediment in rapidly responding headwater catchments. We present preliminary research findings from a densely instrumented research site (Bowmont catchment, Scotland (85km2)) which regularly experiences flood events with associated coarse sediment problems. NFM measures have been installed to capture course sediment and to store water more effectively on the flood plains during these flood events. For example, novel engineered wooden structures ('bar apex log jams') constructed in the river corridor are designed to trap sediment and log bank protection structures have been installed to stop bank erosion. Within a tributary catchment of the Bowmont (0.7km2), new flow restrictors have been installed on a headwater stream to slow the flow whilst collecting coarse sediment. These were designed to have a minimal impact on upland farming practices. In addition, tree planting is also occurring in the catchment for example, within gulley, on the riparian zone and hedgerow belts perpendicular to slopes. During a recent large event, the majority of 40 bar apex structures collected coarse sediment. However, only five were associated with high deposition and modification of the spatial pattern of deposition, which highlighted the importance both of structure design and location of these features to maximise their sediment trapping effectiveness and longevity.

44 CFR 60.25 - Designation, duties, and responsibilities of State Coordinating Agencies.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., Mudslide (i.e., Mudflow)-Prone and Flood-Related Erosion-Prone Areas § 60.25 Designation, duties, and... and coastal flood-prone areas, whenever possible, and provide all relevant technical information to...

44 CFR 60.25 - Designation, duties, and responsibilities of State Coordinating Agencies.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., Mudslide (i.e., Mudflow)-Prone and Flood-Related Erosion-Prone Areas § 60.25 Designation, duties, and... and coastal flood-prone areas, whenever possible, and provide all relevant technical information to...

44 CFR 60.25 - Designation, duties, and responsibilities of State Coordinating Agencies.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., Mudslide (i.e., Mudflow)-Prone and Flood-Related Erosion-Prone Areas § 60.25 Designation, duties, and... and coastal flood-prone areas, whenever possible, and provide all relevant technical information to...

44 CFR 60.25 - Designation, duties, and responsibilities of State Coordinating Agencies.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., Mudslide (i.e., Mudflow)-Prone and Flood-Related Erosion-Prone Areas § 60.25 Designation, duties, and... and coastal flood-prone areas, whenever possible, and provide all relevant technical information to...

Development of cost-effective surfactant flooding technology, Quarterly report, October 1995--December 1995

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pope, G.A.; Sepehrnoori, K.

1995-12-31

The objective of this research is to develop cost-effective surfactant flooding technology by using simulation studies to evaluate and optimize alternative design strategies taking into account reservoir characteristics process chemistry, and process design options such as horizontal wells. Task 1 is the development of an improved numerical method for our simulator that will enable us to solve a wider class of these difficult simulation problems accurately and affordably. Task 2 is the application of this simulator to the optimization of surfactant flooding to reduce its risk and cost. In this quarter, we have continued working on Task 2 to optimizemore » surfactant flooding design and have included economic analysis to the optimization process. An economic model was developed using a spreadsheet and the discounted cash flow (DCF) method of economic analysis. The model was designed specifically for a domestic onshore surfactant flood and has been used to economically evaluate previous work that used a technical approach to optimization. The DCF model outputs common economic decision making criteria, such as net present value (NPV), internal rate of return (IRR), and payback period.« less

Floods in the English River basin, Iowa

USGS Publications Warehouse

Heinitz, A.J.; Riddle, D.E.

1981-01-01

Information describing floods is essential for proper planning, design, and operation of bridges and other structures on or over streams and their flood plains. This report provides information on flood stages and discharges, flood magnitude and frequency, bench mark data, and flood profiles for the English River and some of its tributaries. It covers the English River, the North English River to near Guernsey, the south Eaglish River to Barnes City and the lower reaches of the Biddle English and Deep Rivers

Flood risk analysis for flood control and sediment transportation: a case study in the catchments of the Loess Plateau, China

NASA Astrophysics Data System (ADS)

Wang, Y.; Chang, J.; Guo, A.

2017-12-01

Traditional flood risk analysis focuses on the probability of flood events exceeding the design flood of downstream hydraulic structures while neglecting the influence of sedimentation in river channels on flood control systems. Given this focus, a univariate and copula-based bivariate hydrological risk framework focusing on flood control and sediment transport is proposed in the current work. Additionally, the conditional probabilities of occurrence of different flood events under various extreme precipitation scenarios are estimated by exploiting the copula model. Moreover, a Monte Carlo-based algorithm is used to evaluate the uncertainties of univariate and bivariate hydrological risk. Two catchments located on the Loess plateau are selected as study regions: the upper catchments of the Xianyang and Huaxian stations (denoted as UCX and UCH, respectively). The results indicate that (1) 2-day and 3-day consecutive rainfall are highly correlated with the annual maximum flood discharge (AMF) in UCX and UCH, respectively; and (2) univariate and bivariate return periods, risk and reliability for the purposes of flood control and sediment transport are successfully estimated. Sedimentation triggers higher risks of damaging the safety of local flood control systems compared with the AMF, exceeding the design flood of downstream hydraulic structures in the UCX and UCH. Most importantly, there was considerable sampling uncertainty in the univariate and bivariate hydrologic risk analysis, which would greatly challenge measures of future flood mitigation. The proposed hydrological risk framework offers a promising technical reference for flood risk analysis in sandy regions worldwide.

Exploring the Role of Social Memory of Floods for Designing Flood Early Warning Operations

NASA Astrophysics Data System (ADS)

Girons Lopez, Marc; Di Baldassarre, Giuliano; Grabs, Thomas; Halldin, Sven; Seibert, Jan

2016-04-01

Early warning systems are an important tool for natural disaster mitigation practices, especially for flooding events. Warnings rely on near-future forecasts to provide time to take preventive actions before a flood occurs, thus reducing potential losses. However, on top of the technical capacities, successful warnings require an efficient coordination and communication among a range of different actors and stakeholders. The complexity of integrating the technical and social spheres of warning systems has, however, resulted in system designs neglecting a number of important aspects such as social awareness of floods thus leading to suboptimal results. A better understanding of the interactions and feedbacks among the different elements of early warning systems is therefore needed to improve their efficiency and therefore social resilience. When designing an early warning system two important decisions need to be made regarding (i) the hazard magnitude at and from which a warning should be issued and (ii) the degree of confidence required for issuing a warning. The first decision is usually taken based on the social vulnerability and climatic variability while the second one is related to the performance (i.e. accuracy) of the forecasting tools. Consequently, by estimating the vulnerability and the accuracy of the forecasts, these two variables can be optimized to minimize the costs and losses. Important parameters with a strong influence on the efficiency of warning systems such as social awareness are however not considered in their design. In this study we present a theoretical exploration of the impact of social awareness on the design of early warning systems. For this purpose we use a definition of social memory of flood events as a proxy for flood risk awareness and test its effect on the optimization of the warning system design variables. Understanding the impact of social awareness on warning system design is important to make more robust warnings that can better adapt to different social settings and more efficiently reduce vulnerability.

Integration of social vulnerability into emergency management plans: designing of evacuation routes against flood disasters

NASA Astrophysics Data System (ADS)

Aroca-Jimenez, Estefanía; Bodoque, Jose Maria; Garcia, Juan Antonio; Diez-Herrero, Andres

2017-04-01

Flash floods are highly spatio-temporal localized flood events characterized by reaching a high peak flow in a very short period of time, i.e., generally with times of concentration lower than six hours. Its short duration, which limits or even voids any warning time, means that flash floods are considered to be one of the most destructive natural hazards with the greatest capacity to generate risk, either in terms of the number of people affected globally or the proportion of individual fatalities. The above highlights the importance of a realistic and appropriate design of evacuation strategies in order to reduce flood-related losses, being evacuation planning considered of critical importance for disaster management. Traditionally, evacuation maps have been based on flood-prone areas, shelters or emergency residences location and evacuation routes information. However, evacuation plans rarely consider the spatial distribution of vulnerable population (i.e., people with special needs, mobility constraints or economic difficulties), which usually require assistance from emergency responders. The goal of this research is to elaborate an evacuation map against the occurrence of flash floods by combining geographic information (e.g. roads, health facilities location, sanitary helicopters) and social vulnerability patterns, which are previously obtained from socioeconomic variables (e.g. population, unemployment, dwelling characteristics). To do this, ArcGis Network Analyst tool is used, which allows to calculate the optimal evacuation routes. The methodology proposed here is implemented in the region of Castilla y León (94,230 km2). Urban areas prone to flash flooding are identified taking into account the following requirements: i) city centers are crossed by rivers or streams with a longitudinal slope higher than 0.01 m m-1; ii) city centers are potentially affected by flash floods; and iii) city centers are affected by an area with low or exceptional probability of flooding (i.e., 500-year flood). A total of 3 evacuation routes were designed and automatically traced for each of the 39 urban areas identified as interest, considering the nearest: i) health facility, ii) hospital; and iii) evacuation area (i.e. sports halls or any other). The suitable elaboration of evacuation plans is really important in small mountainous areas prone to flash flooding as they are managed by local organisms where available economic resources are often limited. Furthermore, the short response time obliges emergency responders to act efficiently, which requires the design of evacuation plans taking into account certain social characteristics for evacuation routes designing.

Joint Probability Analysis of Extreme Precipitation and Storm Tide in a Coastal City under Changing Environment

PubMed Central

Xu, Kui; Ma, Chao; Lian, Jijian; Bin, Lingling

2014-01-01

Catastrophic flooding resulting from extreme meteorological events has occurred more frequently and drawn great attention in recent years in China. In coastal areas, extreme precipitation and storm tide are both inducing factors of flooding and therefore their joint probability would be critical to determine the flooding risk. The impact of storm tide or changing environment on flooding is ignored or underestimated in the design of drainage systems of today in coastal areas in China. This paper investigates the joint probability of extreme precipitation and storm tide and its change using copula-based models in Fuzhou City. The change point at the year of 1984 detected by Mann-Kendall and Pettitt’s tests divides the extreme precipitation series into two subsequences. For each subsequence the probability of the joint behavior of extreme precipitation and storm tide is estimated by the optimal copula. Results show that the joint probability has increased by more than 300% on average after 1984 (α = 0.05). The design joint return period (RP) of extreme precipitation and storm tide is estimated to propose a design standard for future flooding preparedness. For a combination of extreme precipitation and storm tide, the design joint RP has become smaller than before. It implies that flooding would happen more often after 1984, which corresponds with the observation. The study would facilitate understanding the change of flood risk and proposing the adaption measures for coastal areas under a changing environment. PMID:25310006

Joint probability analysis of extreme precipitation and storm tide in a coastal city under changing environment.

PubMed

Xu, Kui; Ma, Chao; Lian, Jijian; Bin, Lingling

2014-01-01

Catastrophic flooding resulting from extreme meteorological events has occurred more frequently and drawn great attention in recent years in China. In coastal areas, extreme precipitation and storm tide are both inducing factors of flooding and therefore their joint probability would be critical to determine the flooding risk. The impact of storm tide or changing environment on flooding is ignored or underestimated in the design of drainage systems of today in coastal areas in China. This paper investigates the joint probability of extreme precipitation and storm tide and its change using copula-based models in Fuzhou City. The change point at the year of 1984 detected by Mann-Kendall and Pettitt's tests divides the extreme precipitation series into two subsequences. For each subsequence the probability of the joint behavior of extreme precipitation and storm tide is estimated by the optimal copula. Results show that the joint probability has increased by more than 300% on average after 1984 (α = 0.05). The design joint return period (RP) of extreme precipitation and storm tide is estimated to propose a design standard for future flooding preparedness. For a combination of extreme precipitation and storm tide, the design joint RP has become smaller than before. It implies that flooding would happen more often after 1984, which corresponds with the observation. The study would facilitate understanding the change of flood risk and proposing the adaption measures for coastal areas under a changing environment.

Annual timing of river floods in the Northeast United States: seasonal characterization and temporal trends

NASA Astrophysics Data System (ADS)

Collins, M. J.

2016-12-01

Increases in flood magnitude and frequency have been documented in climate-sensitive watersheds in the Northeast United States. Associated changes in inundation frequency and/or magnitude, or changes in stream channel form and function, can affect human uses of floodplain environments (e.g., dwellings or transportation infrastructure) as well as aquatic and riparian habitats. Historical changes in flood magnitude and frequency also have important implications for designing floodplain infrastructure and channel modifications because well-accepted statistical methods for design-flood prediction require flood records with stationary means and variances. Changes in flood timing during the year may also be impactful, but have not been studied in detail for the Northeast United States. For example, relatively modest shifts in the timing of winter/spring floods can affect the incidence of ice jam complications. Or, changes in spring or fall flood timing may positively or negatively affect a vulnerable life stage for a migratory fish (e.g., egg setting) depending on whether floods occur more frequently before or after the life history event. With this study I apply an objective, probabilistic method for identifying flood seasonality in climate-sensitive watersheds of the Mid-Atlantic and New England regions (Hydrologic Unit Codes 01 and 02). Temporal trends in the timing of floods within significant flood seasons at a site are then analyzed using a method that employs directional statistics. The analyses are based on partial duration flood series that are an average of 85 years long. Documented changes in flood timing during the year are considered in the context of both potential historical impacts and expectations for future flood timing given regional climate change projections.

Quantifying riverine and storm-surge flood risk by single-family residence: application to Texas.

PubMed

Czajkowski, Jeffrey; Kunreuther, Howard; Michel-Kerjan, Erwann

2013-12-01

The development of catastrophe models in recent years allows for assessment of the flood hazard much more effectively than when the federally run National Flood Insurance Program (NFIP) was created in 1968. We propose and then demonstrate a methodological approach to determine pure premiums based on the entire distribution of possible flood events. We apply hazard, exposure, and vulnerability analyses to a sample of 300,000 single-family residences in two counties in Texas (Travis and Galveston) using state-of-the-art flood catastrophe models. Even in zones of similar flood risk classification by FEMA there is substantial variation in exposure between coastal and inland flood risk. For instance, homes in the designated moderate-risk X500/B zones in Galveston are exposed to a flood risk on average 2.5 times greater than residences in X500/B zones in Travis. The results also show very similar average annual loss (corrected for exposure) for a number of residences despite their being in different FEMA flood zones. We also find significant storm-surge exposure outside of the FEMA designated storm-surge risk zones. Taken together these findings highlight the importance of a microanalysis of flood exposure. The process of aggregating risk at a flood zone level-as currently undertaken by FEMA-provides a false sense of uniformity. As our analysis indicates, the technology to delineate the flood risks exists today. © 2013 Society for Risk Analysis.

The effects of low impact development on urban flooding under different rainfall characteristics.

PubMed

Qin, Hua-peng; Li, Zhuo-xi; Fu, Guangtao

2013-11-15

Low impact development (LID) is generally regarded as a more sustainable solution for urban stormwater management than conventional urban drainage systems. However, its effects on urban flooding at a scale of urban drainage systems have not been fully understood particularly when different rainfall characteristics are considered. In this paper, using an urbanizing catchment in China as a case study, the effects of three LID techniques (swale, permeable pavement and green roof) on urban flooding are analyzed and compared with the conventional drainage system design. A range of storm events with different rainfall amounts, durations and locations of peak intensity are considered for holistic assessment of the LID techniques. The effects are measured by the total flood volume reduction during a storm event compared to the conventional drainage system design. The results obtained indicate that all three LID scenarios are more effective in flood reduction during heavier and shorter storm events. Their performance, however, varies significantly according to the location of peak intensity. That is, swales perform best during a storm event with an early peak, permeable pavements perform best with a middle peak, and green roofs perform best with a late peak, respectively. The trends of flood reduction can be explained using a newly proposed water balance method, i.e., by comparing the effective storage depth of the LID designs with the accumulative rainfall amounts at the beginning and end of flooding in the conventional drainage system. This paper provides an insight into the performance of LID designs under different rainfall characteristics, which is essential for effective urban flood management. Copyright © 2013 Elsevier Ltd. All rights reserved.

Assessing and Mitigating Hurricane Storm Surge Risk in a Changing Environment

NASA Astrophysics Data System (ADS)

Lin, N.; Shullman, E.; Xian, S.; Feng, K.

2017-12-01

Hurricanes have induced devastating storm surge flooding worldwide. The impacts of these storms may worsen in the coming decades because of rapid coastal development coupled with sea-level rise and possibly increasing storm activity due to climate change. Major advances in coastal flood risk management are urgently needed. We present an integrated dynamic risk analysis for flooding task (iDraft) framework to assess and manage coastal flood risk at the city or regional scale, considering integrated dynamic effects of storm climatology change, sea-level rise, and coastal development. We apply the framework to New York City. First, we combine climate-model projected storm surge climatology and sea-level rise with engineering- and social/economic-model projected coastal exposure and vulnerability to estimate the flood damage risk for the city over the 21st century. We derive temporally-varying risk measures such as the annual expected damage as well as temporally-integrated measures such as the present value of future losses. We also examine the individual and joint contributions to the changing risk of the three dynamic factors (i.e., sea-level rise, storm change, and coastal development). Then, we perform probabilistic cost-benefit analysis for various coastal flood risk mitigation strategies for the city. Specifically, we evaluate previously proposed mitigation measures, including elevating houses on the floodplain and constructing flood barriers at the coast, by comparing their estimated cost and probability distribution of the benefit (i.e., present value of avoided future losses). We also propose new design strategies, including optimal design (e.g., optimal house elevation) and adaptive design (e.g., flood protection levels that are designed to be modified over time in a dynamic and uncertain environment).

Impact of Atmospheric Aerosols on Solar Photovoltaic Electricity Generation in China

NASA Astrophysics Data System (ADS)

Li, X.; Mauzerall, D. L.; Wagner, F.; Peng, W.; Yang, J.

2016-12-01

Hurricanes have induced devastating storm surge flooding worldwide. The impacts of these storms may worsen in the coming decades because of rapid coastal development coupled with sea-level rise and possibly increasing storm activity due to climate change. Major advances in coastal flood risk management are urgently needed. We present an integrated dynamic risk analysis for flooding task (iDraft) framework to assess and manage coastal flood risk at the city or regional scale, considering integrated dynamic effects of storm climatology change, sea-level rise, and coastal development. We apply the framework to New York City. First, we combine climate-model projected storm surge climatology and sea-level rise with engineering- and social/economic-model projected coastal exposure and vulnerability to estimate the flood damage risk for the city over the 21st century. We derive temporally-varying risk measures such as the annual expected damage as well as temporally-integrated measures such as the present value of future losses. We also examine the individual and joint contributions to the changing risk of the three dynamic factors (i.e., sea-level rise, storm change, and coastal development). Then, we perform probabilistic cost-benefit analysis for various coastal flood risk mitigation strategies for the city. Specifically, we evaluate previously proposed mitigation measures, including elevating houses on the floodplain and constructing flood barriers at the coast, by comparing their estimated cost and probability distribution of the benefit (i.e., present value of avoided future losses). We also propose new design strategies, including optimal design (e.g., optimal house elevation) and adaptive design (e.g., flood protection levels that are designed to be modified over time in a dynamic and uncertain environment).

76 FR 17019 - List of Approved Spent Fuel Storage Casks: HI-STORM Flood/Wind Addition

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-28

... Storage Casks: HI-STORM Flood/Wind Addition AGENCY: Nuclear Regulatory Commission. ACTION: Direct final... regulations to add the HI-STORM Flood/Wind cask system to the ``List of Approved Spent Fuel Storage Casks... cask designs. Discussion This rule will add the Holtec HI-STORM Flood/Wind (FW) cask system to the list...

Using Science and Much More to Beat the Flood

ERIC Educational Resources Information Center

Seeley, Claire

2014-01-01

The Beat the Flood challenge involves designing and building a model flood-proof home, which is then tested in "flood" conditions. It is set on the fictitious Watu Island. The children form teams, with each team member being assigned a responsibility for the duration of the task--team leader, chief recorder, and resource manager. This…

Increase in flood risk resulting from climate change in a developed urban watershed - the role of storm temporal patterns

NASA Astrophysics Data System (ADS)

Hettiarachchi, Suresh; Wasko, Conrad; Sharma, Ashish

2018-03-01

The effects of climate change are causing more frequent extreme rainfall events and an increased risk of flooding in developed areas. Quantifying this increased risk is of critical importance for the protection of life and property as well as for infrastructure planning and design. The updated National Oceanic and Atmospheric Administration (NOAA) Atlas 14 intensity-duration-frequency (IDF) relationships and temporal patterns are widely used in hydrologic and hydraulic modeling for design and planning in the United States. Current literature shows that rising temperatures as a result of climate change will result in an intensification of rainfall. These impacts are not explicitly included in the NOAA temporal patterns, which can have consequences on the design and planning of adaptation and flood mitigation measures. In addition there is a lack of detailed hydraulic modeling when assessing climate change impacts on flooding. The study presented in this paper uses a comprehensive hydrologic and hydraulic model of a fully developed urban/suburban catchment to explore two primary questions related to climate change impacts on flood risk. (1) How do climate change effects on storm temporal patterns and rainfall volumes impact flooding in a developed complex watershed? (2) Is the storm temporal pattern as critical as the total volume of rainfall when evaluating urban flood risk? We use the NOAA Atlas 14 temporal patterns, along with the expected increase in temperature for the RCP8.5 scenario for 2081-2100, to project temporal patterns and rainfall volumes to reflect future climatic change. The model results show that different rainfall patterns cause variability in flood depths during a storm event. The changes in the projected temporal patterns alone increase the risk of flood magnitude up to 35 %, with the cumulative impacts of temperature rise on temporal patterns and the storm volume increasing flood risk from 10 to 170 %. The results also show that regional storage facilities are sensitive to rainfall patterns that are loaded in the latter part of the storm duration, while extremely intense short-duration storms will cause flooding at all locations. This study shows that changes in temporal patterns will have a significant impact on urban/suburban flooding and need to be carefully considered and adjusted to account for climate change when used for the design and planning of future storm water systems.

Assessing the impact of climate and land use changes on extreme floods in a large tropical catchment

NASA Astrophysics Data System (ADS)

Jothityangkoon, Chatchai; Hirunteeyakul, Chow; Boonrawd, Kowit; Sivapalan, Murugesu

2013-05-01

In the wake of the recent catastrophic floods in Thailand, there is considerable concern about the safety of large dams designed and built some 50 years ago. In this paper a distributed rainfall-runoff model appropriate for extreme flood conditions is used to generate revised estimates of the Probable Maximum Flood (PMF) for the Upper Ping River catchment (area 26,386 km2) in northern Thailand, upstream of location of the large Bhumipol Dam. The model has two components: a continuous water balance model based on a configuration of parameters estimated from climate, soil and vegetation data and a distributed flood routing model based on non-linear storage-discharge relationships of the river network under extreme flood conditions. The model is implemented under several alternative scenarios regarding the Probable Maximum Precipitation (PMP) estimates and is also used to estimate the potential effects of both climate change and land use and land cover changes on the extreme floods. These new estimates are compared against estimates using other hydrological models, including the application of the original prediction methods under current conditions. Model simulations and sensitivity analyses indicate that a reasonable Probable Maximum Flood (PMF) at the dam site is 6311 m3/s, which is only slightly higher than the original design flood of 6000 m3/s. As part of an uncertainty assessment, the estimated PMF is sensitive to the design method, input PMP, land use changes and the floodplain inundation effect. The increase of PMP depth by 5% can cause a 7.5% increase in PMF. Deforestation by 10%, 20%, 30% can result in PMF increases of 3.1%, 6.2%, 9.2%, respectively. The modest increase of the estimated PMF (to just 6311 m3/s) in spite of these changes is due to the factoring of the hydraulic effects of trees and buildings on the floodplain as the flood situation changes from normal floods to extreme floods, when over-bank flows may be the dominant flooding process, leading to a substantial reduction in the PMF estimates.

Prioritizing the Components of Vulnerability: A Genetic Algorithm Minimization of Flood Risk

NASA Astrophysics Data System (ADS)

Bongolan, Vena Pearl; Ballesteros, Florencio; Baritua, Karessa Alexandra; Junne Santos, Marie

2013-04-01

We define a flood resistant city as an optimal arrangement of communities according to their traits, with the goal of minimizing the flooding vulnerability via a genetic algorithm. We prioritize the different components of flooding vulnerability, giving each component a weight, thus expressing vulnerability as a weighted sum. This serves as the fitness function for the genetic algorithm. We also allowed non-linear interactions among related but independent components, viz, poverty and mortality rate, and literacy and radio/ tv penetration. The designs produced reflect the relative importance of the components, and we observed a synchronicity between the interacting components, giving us a more consistent design.

46 CFR 42.20-6 - Flooding standard: Type “A” vessels.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Flooding standard: Type âAâ vessels. 42.20-6 Section 42... FOREIGN VOYAGES BY SEA Freeboards § 42.20-6 Flooding standard: Type “A” vessels. (a) Design calculations... specified in § 42.20-12 assuming the damage specified in § 42.20-11 as applied to the following flooding...

46 CFR 42.20-6 - Flooding standard: Type “A” vessels.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Flooding standard: Type âAâ vessels. 42.20-6 Section 42... FOREIGN VOYAGES BY SEA Freeboards § 42.20-6 Flooding standard: Type “A” vessels. (a) Design calculations... specified in § 42.20-12 assuming the damage specified in § 42.20-11 as applied to the following flooding...

46 CFR 42.20-6 - Flooding standard: Type “A” vessels.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Flooding standard: Type âAâ vessels. 42.20-6 Section 42... FOREIGN VOYAGES BY SEA Freeboards § 42.20-6 Flooding standard: Type “A” vessels. (a) Design calculations... specified in § 42.20-12 assuming the damage specified in § 42.20-11 as applied to the following flooding...

46 CFR 42.20-6 - Flooding standard: Type “A” vessels.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Flooding standard: Type âAâ vessels. 42.20-6 Section 42... FOREIGN VOYAGES BY SEA Freeboards § 42.20-6 Flooding standard: Type “A” vessels. (a) Design calculations... specified in § 42.20-12 assuming the damage specified in § 42.20-11 as applied to the following flooding...

46 CFR 42.20-6 - Flooding standard: Type “A” vessels.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Flooding standard: Type âAâ vessels. 42.20-6 Section 42... FOREIGN VOYAGES BY SEA Freeboards § 42.20-6 Flooding standard: Type “A” vessels. (a) Design calculations... specified in § 42.20-12 assuming the damage specified in § 42.20-11 as applied to the following flooding...

Improving techniques to estimate the magnitude and frequency of floods on urban streams in South Carolina, North Carolina, and Georgia, 2011 (ver. 1.1, March 2014) : U.S. Geological Survey scientific investigations report 2014-5030.

DOT National Transportation Integrated Search

2014-03-01

Reliable estimates of the magnitude and frequency : of floods are essential for the design of transportation and : water-conveyance structures, flood-insurance studies, and : flood-plain management. Such estimates are particularly : important in dens...

Global river flood hazard maps: hydraulic modelling methods and appropriate uses

NASA Astrophysics Data System (ADS)

Townend, Samuel; Smith, Helen; Molloy, James

2014-05-01

Flood hazard is not well understood or documented in many parts of the world. Consequently, the (re-)insurance sector now needs to better understand where the potential for considerable river flooding aligns with significant exposure. For example, international manufacturing companies are often attracted to countries with emerging economies, meaning that events such as the 2011 Thailand floods have resulted in many multinational businesses with assets in these regions incurring large, unexpected losses. This contribution addresses and critically evaluates the hydraulic methods employed to develop a consistent global scale set of river flood hazard maps, used to fill the knowledge gap outlined above. The basis of the modelling approach is an innovative, bespoke 1D/2D hydraulic model (RFlow) which has been used to model a global river network of over 5.3 million kilometres. Estimated flood peaks at each of these model nodes are determined using an empirically based rainfall-runoff approach linking design rainfall to design river flood magnitudes. The hydraulic model is used to determine extents and depths of floodplain inundation following river bank overflow. From this, deterministic flood hazard maps are calculated for several design return periods between 20-years and 1,500-years. Firstly, we will discuss the rationale behind the appropriate hydraulic modelling methods and inputs chosen to produce a consistent global scaled river flood hazard map. This will highlight how a model designed to work with global datasets can be more favourable for hydraulic modelling at the global scale and why using innovative techniques customised for broad scale use are preferable to modifying existing hydraulic models. Similarly, the advantages and disadvantages of both 1D and 2D modelling will be explored and balanced against the time, computer and human resources available, particularly when using a Digital Surface Model at 30m resolution. Finally, we will suggest some appropriate uses of global scale hazard maps and explore how this new approach can be invaluable in areas of the world where flood hazard and risk have not previously been assessed.

Assessing sedimentation issues within aging flood-control reservoirs

USDA-ARS?s Scientific Manuscript database

Flood control reservoirs designed and built by federal agencies have been extremely effective in reducing the ravages of floods nationwide. Yet some structures are being removed for a variety of reasons, while other structures are aging rapidly and require either rehabilitation or decommissioning. ...

44 CFR 78.2 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... INSURANCE AND HAZARD MITIGATION National Flood Insurance Program FLOOD MITIGATION ASSISTANCE § 78.2... organization, that has zoning and building code jurisdiction over a particular area having special flood..., that is designated to develop and administer a mitigation plan by political subdivisions, all of which...

44 CFR 78.2 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program FLOOD MITIGATION ASSISTANCE § 78... organization, that has zoning and building code jurisdiction over a particular area having special flood..., that is designated to develop and administer a mitigation plan by political subdivisions, all of which...

44 CFR 78.2 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program FLOOD MITIGATION ASSISTANCE § 78... organization, that has zoning and building code jurisdiction over a particular area having special flood..., that is designated to develop and administer a mitigation plan by political subdivisions, all of which...

44 CFR 78.2 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program FLOOD MITIGATION ASSISTANCE § 78... organization, that has zoning and building code jurisdiction over a particular area having special flood..., that is designated to develop and administer a mitigation plan by political subdivisions, all of which...

44 CFR 78.2 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program FLOOD MITIGATION ASSISTANCE § 78... organization, that has zoning and building code jurisdiction over a particular area having special flood..., that is designated to develop and administer a mitigation plan by political subdivisions, all of which...

Assessment of watershed regionalization for the land use change parameterization

NASA Astrophysics Data System (ADS)

Randusová, Beata; Kohnová, Silvia; Studvová, Zuzana; Marková, Romana; Nosko, Radovan

2016-04-01

The estimation of design discharges and water levels of extreme floods is one of the most important parts of the design process for a large number of engineering projects and studies. Floods and other natural hazards initiated by climate, soil, and land use changes are highly important in the 21st century. Flood risks and design flood estimation is particularly challenging. Methods of design flood estimation can be applied either locally or regionally. To obtain the design values in such cases where no recorded data exist, many countries have adopted procedures that fit the local conditions and requirements. One of these methods is the Soil Conservation Service - Curve number (SCS-CN) method which is often used in design flood estimation for ungauged sites. The SCS-CN method is an empirical rainfall-runoff model developed by the USDA Natural Resources Conservation Service (formerly called the Soil Conservation Service or SCS). The runoff curve number (CN) is based on the hydrological soil characteristics, land use, land management and antecedent saturation conditions of soil. This study is focused on development of the SCS-CN methodology for the changing land use conditions in Slovak basins (with the pilot site of the Myjava catchment), which regionalize actual state of land use data and actual rainfall and discharge measurements of the selected river basins. In this study the state of the water erosion and sediment transport along with a subsequent proposal of erosion control measures was analyzed as well. The regionalized SCS-CN method was subsequently used for assessing the effectiveness of this control measure to reduce runoff from the selected basin. For the determination of the sediment transport from the control measure to the Myjava basin, the SDR (Sediment Delivery Ratio) model was used.

From flood management systems to flood resilient systems: integration of flood resilient technologies

NASA Astrophysics Data System (ADS)

Salagnac, J.-L.; Diez, J.; Tourbier, J.

2012-04-01

Flooding has always been a major risk world-wide. Humans chose to live and develop settlements close to water (rivers, seas) due to the resources water brings, i.e. food, energy, capacity to economically transport persons and goods, and recreation. However, the risk from flooding, including pluvial flooding, often offsets these huge advantages. Floods sometimes have terrible consequences from both a human and economic point of view. The permanence and growth of urban areas in flood-prone zones despite these risks is a clear indication of the choices of concerned human groups. The observed growing concentration of population along the sea shore, the increase of urban population worldwide, the exponential growth of the world population and possibly climate change are factors that confirm flood will remain a major issue for the next decades. Flood management systems are designed and implemented to cope with such situations. In spite of frequent events, lessons look to be difficult to draw out and progresses are rather slow. The list of potential triggers to improve flood management systems is nevertheless well established: information, education, awareness raising, alert, prevention, protection, feedback from events, ... Many disciplines are concerned which cover a wide range of soft and hard sciences. A huge amount of both printed and electronic literature is available. Regulations are abundant. In spite of all these potentially favourable elements, similar questions spring up after each new significant event: • Was the event forecast precise enough? • Was the alert system efficient? • Why were buildings built in identified flood prone areas? • Why did the concerned population not follow instructions? • Why did the dike break? • What should we do to avoid it happens again? • What about damages evaluation, wastes and debris evacuation, infrastructures and buildings repair, activity recovery, temporary relocation of inhabitants, health concerns, insurance concerns, water-resistant materials, vulnerability assessment ? Flood resilient system (FReS) concept has been proposed as a new framework to address flood situations. Such systems intend to better approach such situations from a holistic point of view. FReS encompass ecologic, spatial, structural, social, disaster relief and flood risk aspects. FReS design and implementation conditions have been addressed by the FP7 SMARTeST (Smart Resilience Technology, Systems and Tools) project. The focus of this Project on the use of available and innovative communication, forecasting and flood protection technologies leads to an original contribution which highlights both the scope and the limits of this technology driven approach. These reflexions contribute to the elaboration of guidelines for the design of FReS.

READY: a web-based geographical information system for enhanced flood resilience through raising awareness in citizens

NASA Astrophysics Data System (ADS)

Albano, R.; Sole, A.; Adamowski, J.

2015-02-01

As evidenced by the EU Floods Directive (2007/60/EC), flood management strategies in Europe have undergone a shift in focus in recent years. The goal of flood prevention using structural measures has been replaced by an emphasis on the management of flood risks using non-structural measures. One implication of this is that it is no longer public authorities alone who take responsibility for flood management. A broader range of stakeholders, who may experience the negative effects of flooding, also take on responsibility to protect themselves. Therefore, it is vital that information concerning flood risks are conveyed to those who may be affected in order to facilitate the self-protection of citizens. Experience shows that even where efforts have been made to communicate flood risks, problems persist. There is a need for the development of new tools, which are able to rapidly disseminate flood risk information to the general public. To be useful, these tools must be able to present information relevant to the location of the user. Moreover, the content and design of the tool need to be adjusted to laypeople's needs. Dissemination and communication influences both people's access to and understanding of natural risk information. Such a tool could be a useful aid to effective management of flood risks. To address this gap, a Web-based Geographical Information System, (WebGIS), has been developed through the collaborative efforts of a group of scientists, hazard and risk analysts and managers, GIS analysts, system developers and communication designers. This tool, called "READY: Risk, Extreme Events, Adaptation, Defend Yourself", aims to enhance the general public knowledge of flood risk, making them more capable of responding appropriately during a flood event. The READY WebGIS has allowed for the visualization and easy querying of a complex hazard and risk database thanks to a high degree of interactivity and its easily readable maps. In this way, READY has enabled fast exploration of alternative flood scenarios or past calamitous events. Combined also with a system of graphic symbols designed ad hoc for communication of self-protection behaviors, it is believed READY could lead to an increase in citizen participation, informed discussion and consensus building. The platform has been developed for a site-specific application, i.e. the Basilicata Region, Italy, has been selected as pilot application area. The goal of the prototype is to raise citizen awareness of flood risks, and to build social capacity and enhanced resilience to flood events.

READY: a web-based geographical information system for enhanced flood resilience through raising awareness in citizens

NASA Astrophysics Data System (ADS)

Albano, R.; Sole, A.; Adamowski, J.

2015-07-01

As evidenced by the EU Floods Directive (2007/60/EC), flood management strategies in Europe have undergone a shift in focus in recent years. The goal of flood prevention using structural measures has been replaced by an emphasis on the management of flood risks using non-structural measures. One implication of this is that public authorities alone not only take responsibility for flood management. A broader range of stakeholders, who may personally experience the negative effects of flooding, also take on responsibility for protecting themselves. Therefore, it is vital that information concerning flood risks is conveyed to those who may be affected in order to facilitate the self-protection of citizens. Experience shows that problems persist even where efforts have been made to communicate flood risks. There is a need for the development of new tools that are able to rapidly disseminate flood-risk information to the general public. To be useful these tools must be able to present information relevant to the location of the user. Moreover, the content and design of the tool need to be adjusted to laypeople's needs. Dissemination and communication influence both people's access to and understanding of natural risk information. Such a tool could be a useful aid to effective management of flood risks. To address this gap, a web-based geographical information system (WebGIS) has been developed through the collaborative efforts of a group of scientists, hazard and risk analysts and managers, GIS analysts, system developers and communication designers. This tool, called "READY: Risk, Extreme Events, Adaptation, Defend Yourself", aims to enhance the general public knowledge of flood risk, making citizens more capable of responding appropriately during a flood event. The READY WebGIS has allowed for the visualization and easy querying of a complex hazard and risk database thanks to a high degree of interactivity and easily read maps. In this way, READY has enabled fast exploration of alternative flood scenarios or past calamitous events. Combined also with a system of graphic symbols designed ad hoc for communication of self-protection behaviours, it is believed READY could lead to an increase in citizen participation, informed discussion and consensus building. The platform has been developed for a site-specific application: the Basilicata region, Italy, has been selected as pilot application area. The goal of the prototype is to raise citizen awareness of flood risks and to build social capacity and enhanced resilience to flood events.

44 CFR 79.2 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program FLOOD MITIGATION GRANTS § 79.2... special flood hazards, and is participating in the NFIP; or (2) A political subdivision of a State, or other authority that is designated by a political subdivision to develop and administer a mitigation...

Early Warning System of Flood Disaster Based on Ultrasonic Sensors and Wireless Technology

NASA Astrophysics Data System (ADS)

Indrasari, W.; Iswanto, B. H.; Andayani, M.

2018-04-01

A flood disaster provides considerable losses to the people who live around the river. To mitigate losses of material due to flood disaster required an early warning system of flood disaster. For that reason, it necessary to design a system that provide alert to the people prior the flood disaster. And this paper describes development of a device for early detection system of flood disasters. This device consists of two ultrasonic sensors as a water level detector, and a water flow sensor as a water flow velocity sensor. The wireless technology and GSM is used as an information medium. The system is designed based on water level conditions in the Katulampa Dam, Bogor. Characterization of water level detector showed that the device effectively works in a range of water level of 14-250 cm, with a maximum relative error of 4.3%. Meanwhile the wireless works properly as far as 75 m, and the SMS transmission time is 8.20 second.

Social impact of the 2004 Manawatu floods and the 'hollowing out' of rural New Zealand.

PubMed

Smith, Willie; Davies-Colley, Christian; Mackay, Alec; Bankoff, Greg

2011-07-01

The Manawatu floods of 2004 have had significant, long-lasting social consequences. This paper draws on findings from a series of detailed surveys of 39 farm households directly affected by the floods and 17 individuals directly involved in managing the flood recovery programme. The nature of the impact on rural families highlights how the 'hollowing out' of rural New Zealand has changed the capacity of rural communities to respond to natural hazards and increased their sense of isolation. In addition, the floods exposed the vulnerability of rural communities. This is shown to have implications for policies designed to build resilience and improve responses to adverse events, including the need to support local, community initiatives on self-reliance and mutual support. Approaches to manage better long-term flood risks should be designed within a context of ongoing rural decline that has compromised the health of both individuals and communities. © 2011 The Author(s). Disasters © Overseas Development Institute, 2011.

Techniques for estimating magnitude and frequency of floods in Minnesota

USGS Publications Warehouse

Guetzkow, Lowell C.

1977-01-01

 Estimating relations have been developed to provide engineers and designers with improved techniques for defining flow-frequency characteristics to satisfy hydraulic planning and design requirements. The magnitude and frequency of floods up to the 100-year recurrence interval can be determined for most streams in Minnesota by methods presented. By multiple regression analysis, equations have been developed for estimating flood-frequency relations at ungaged sites on natural flow streams. Eight distinct hydrologic regions are delineated within the State with boundaries defined generally by river basin divides. Regression equations are provided for each region which relate selected frequency floods to significant basin parameters. For main-stem streams, graphs are presented showing floods for selected recurrence intervals plotted against contributing drainage area. Flow-frequency estimates for intervening sites along the Minnesota River, Mississippi River, and the Red River of the North can be derived from these graphs. Flood-frequency characteristics are tabulated for 201 paging stations having 10 or more years of record.

Influence of flood risk characteristics on flood insurance demand: a comparison between Germany and the Netherlands

NASA Astrophysics Data System (ADS)

Seifert, I.; Botzen, W. J. W.; Kreibich, H.; Aerts, J. C. J. H.

2013-07-01

The existence of sufficient demand for insurance coverage against infrequent losses is important for the adequate function of insurance markets for natural disaster risks. This study investigates how characteristics of flood risk influence household flood insurance demand based on household surveys undertaken in Germany and the Netherlands. Our analyses confirm the hypothesis that willingness to pay (WTP) for insurance against medium-probability medium-impact flood risk in Germany is higher than WTP for insurance against low-probability high-impact flood risk in the Netherlands. These differences in WTP can be related to differences in flood experience, individual risk perceptions, and the charity hazard. In both countries there is a need to stimulate flood insurance demand if a relevant role of private insurance in flood loss compensation is regarded as desirable, for example, by making flood insurance compulsory or by designing information campaigns.

Evaluation of the flood risk factor in the design of box culverts, volume 1 : theoretical development.

DOT National Transportation Integrated Search

1979-09-01

"The work presented in this report represents a preliminary effort to integrate economic factors with the physics of highway drainage. Conventional culvert design rests on the selection of a flood peak flow having a particular return period; for exam...

A methodology to derive Synthetic Design Hydrographs for river flood management

NASA Astrophysics Data System (ADS)

Tomirotti, Massimo; Mignosa, Paolo

2017-12-01

The design of flood protection measures requires in many cases not only the estimation of the peak discharges, but also of the volume of the floods and its time distribution. A typical solution to this kind of problems is the formulation of Synthetic Design Hydrographs (SDHs). In this paper a methodology to derive SDHs is proposed on the basis of the estimation of the Flow Duration Frequency (FDF) reduction curve and of a Peak-Duration (PD) relationship furnishing respectively the quantiles of the maximum average discharge and the average peak position in each duration. The methodology is intended to synthesize the main features of the historical floods in a unique SDH for each return period. The shape of the SDH is not selected a priori but is a result of the behaviour of FDF and PD curves, allowing to account in a very convenient way for the variability of the shapes of the observed hydrographs at local time scale. The validation of the methodology is performed with reference to flood routing problems in reservoirs, lakes and rivers. The results obtained demonstrate the capability of the SDHs to describe the effects of different hydraulic systems on the statistical regime of floods, even in presence of strong modifications induced on the probability distribution of peak flows.

Delineating risk zones and evaluation of shelter centres for flood disaster management along the Pahang River Basin, Malaysia

PubMed Central

Isahak, Anizan; Siwar, Chamhuri; Ismail, Shaharuddin M.; Hanafi, Zulkifli; Zainuddin, Mohd S.

2018-01-01

Shelter centres are important locations to safeguard people from helpless situations and are an integral part of disaster risk reduction (DRR), particularly for flood DRR. The establishment of shelter centres, and their design based on scientific assessment, is crucial. Yet, they are very much related to the geographic location, socio-economic conditions and the livelihoods of the affected communities. However, many parts of the developing world are still lagging behind in ensuring such scientific design. Considering the flood disaster in 2014 that affected the residents living along the Pahang River Basin, in this study we delineate the communities at risk and evaluate the existing shelter centres to determine how they reduce people’s vulnerability to the risks associated with rural and urban landscapes. We used spatial analysis tools to delineate risk zones and to evaluate existing evacuation systems. A flood disaster risk map was produced to determine which communities are living with risks. Subsequently, the distribution of shelter centres examined whether they are able to support people living at the flood risk zones. These centres were also evaluated using a set of international guidelines for effective disaster shelters. This reveals that the number of shelter centres is not adequate. The designation and designing of shelter centres are not being done scientifically. The maps produced here have a lot of potential to support disaster management decisions, in particular site selection and the prioritisation of centres. The study concludes with a set of guidelines and recommendations for structural and non-structural measures, such as alternative livelihoods and the potential of ecotourism, which may improve the resilience among flood-affected communities; and the decision-making process for the overall flood DRR initiatives.

The 3D Elevation Program—Flood risk management

USGS Publications Warehouse

Carswell, William J.; Lukas, Vicki

2018-01-25

Flood-damage reduction in the United States has been a longstanding but elusive societal goal. The national strategy for reducing flood damage has shifted over recent decades from a focus on construction of flood-control dams and levee systems to a three-pronged strategy to (1) improve the design and operation of such structures, (2) provide more accurate and accessible flood forecasting, and (3) shift the Federal Emergency Management Agency (FEMA) National Flood Insurance Program to a more balanced, less costly flood-insurance paradigm. Expanding the availability and use of high-quality, three-dimensional (3D) elevation information derived from modern light detection and ranging (lidar) technologies to provide essential terrain data poses a singular opportunity to dramatically enhance the effectiveness of all three components of this strategy. Additionally, FEMA, the National Weather Service, and the U.S. Geological Survey (USGS) have developed tools and joint program activities to support the national strategy.The USGS 3D Elevation Program (3DEP) has the programmatic infrastructure to produce and provide essential terrain data. This infrastructure includes (1) data acquisition partnerships that leverage funding and reduce duplicative efforts, (2) contracts with experienced private mapping firms that ensure acquisition of consistent, low-cost 3D elevation data, and (3) the technical expertise, standards, and specifications required for consistent, edge-to-edge utility across multiple collection platforms and public access unfettered by individual database designs and limitations.High-quality elevation data, like that collected through 3DEP, are invaluable for assessing and documenting flood risk and communicating detailed information to both responders and planners alike. Multiple flood-mapping programs make use of USGS streamflow and 3DEP data. Flood insurance rate maps, flood documentation studies, and flood-inundation map libraries are products of these programs.

The Prediflood database. A new tool for an integrated approach to historical floods in Catalonia (NE Iberian Peninsula), AD 1033-2013

NASA Astrophysics Data System (ADS)

Barriendos, Mariano; Carles Balasch Solanes, Josep; Tuset, Jordi; Lluís Ruiz-Bellet, Josep

2014-05-01

Available information of historical floods can improve the management of hydroclimatic hazards. This approach is useful in ungauged basins or with short instrumental data series. On the other hand, flood risk is increasing due to both the expansion of human land occupation and the modification of rainfall patterns in the present global climatic change scenario. Within the Prediflood Project, we have designed an integrated database of historical floods in Catalonia with the aim to feed data to: 1) Meteorological reconstruction and modelling. 2) Hydrological and hydraulic reconstruction. 3) Human impacts evaluation, of these floods. The firsts steps of the database design focus on spatial location and on the quality of the data sources in three levels: 1) Historical documentary sources and newspapers contemporary with the floods. 2) Local historiography. 3) Technical reports. After the application of historiographical methodologies, more than 2300 flood records have been added to the database so far. Despite the completion of the database is still a work in progress, the firsts analyses are already underway and focus on the largest floods with catastrophic effects simultaneously on more than 15 catchments: November 1617, October 1787, September 1842, May 1853, September 1874, January 1898, October 1907, October 1940, September 1962, November 1982, October 1994 and others.

Exploring governance learning: How policymakers draw on evidence, experience and intuition in designing participatory flood risk planning.

PubMed

Newig, Jens; Kochskämper, Elisa; Challies, Edward; Jager, Nicolas W

2016-01-01

The importance of designing suitable participatory governance processes is generally acknowledged. However, less emphasis has been put on how decision-makers design such processes, and how they learn about doing so. While the policy learning literature has tended to focus on the substance of policy, little research is available on learning about the design of governance. Here, we explore different approaches to learning among German policymakers engaged in implementing the European Floods Directive. We draw on official planning documents and expert interviews with state-level policymakers to focus on learning about the procedural aspects of designing and conducting participatory flood risk management planning. Drawing on the policy learning and evidence-based governance literatures, we conceptualise six types of instrumental 'governance learning' according to sources of learning (endogenous and exogenous) and modes of learning (serial and parallel). We empirically apply this typology in the context of diverse participatory flood risk management planning processes currently unfolding across the German federal states. We find that during the first Floods Directive planning cycle, policymakers have tended to rely on prior experience in their own federal states with planning under the Water Framework Directive to inform the design and carrying out of participatory processes. In contrast, policymakers only sporadically look to experiences from other jurisdictions as a deliberate learning strategy. We argue that there is scope for more coordinated and systematic learning on designing effective governance, and that the latter might benefit from more openness to experimentation and learning on the part of policymakers.

77 FR 28891 - National Flood Insurance Program Programmatic Environmental Impact Statement

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-16

... critical habitat. This effort will result in a comprehensive series of policy recommendations designed to transition the NFIP toward a more resilient, sustainable, and comprehensive approach to flood risk management... insurance is designed to provide a financial alternative and to reduce the escalating costs of Federal...

Development of flood routing simulation system of digital Qingjiang based on integrated spatial information technology

NASA Astrophysics Data System (ADS)

Yuan, Yanbin; Zhou, You; Zhu, Yaqiong; Yuan, Xiaohui; Sælthun, N. R.

2007-11-01

Based on digital technology, flood routing simulation system development is an important component of "digital catchment". Taking QingJiang catchment as a pilot case, in-depth analysis on informatization of Qingjiang catchment management being the basis, aiming at catchment data's multi-source, - dimension, -element, -subject, -layer and -class feature, the study brings the design thought and method of "subject-point-source database" (SPSD) to design system structure in order to realize the unified management of catchments data in great quantity. Using the thought of integrated spatial information technology for reference, integrating hierarchical structure development model of digital catchment is established. The model is general framework of the flood routing simulation system analysis, design and realization. In order to satisfy the demands of flood routing three-dimensional simulation system, the object-oriented spatial data model are designed. We can analyze space-time self-adapting relation between flood routing and catchments topography, express grid data of terrain by using non-directed graph, apply breadth first search arithmetic, set up search method for the purpose of dynamically searching stream channel on the basis of simulated three-dimensional terrain. The system prototype is therefore realized. Simulation results have demonstrated that the proposed approach is feasible and effective in the application.

Review Article: Structural flood-protection measures referring to several European case studies

NASA Astrophysics Data System (ADS)

Kryžanowski, A.; Brilly, M.; Rusjan, S.; Schnabl, S.

2014-01-01

The paper presents a review of structural measures that were taken to cope with floods in some cities along the Danube River, such as Vienna, Bratislava, and Belgrade. These cities were also considered as case studies within the KULTURisk project. The structural measures are reviewed and compared to each other according to the type, duration of application, the return period of the design flood event, how the project measures are integrated into spatial planning and the problems that occur in the flood defences today. Based on this review, some suggestions are given on how to improve the flood risk management in flood-prone areas.

Technique for estimating depth of floods in Tennessee

USGS Publications Warehouse

Gamble, C.R.

1983-01-01

Estimates of flood depths are needed for design of roadways across flood plains and for other types of construction along streams. Equations for estimating flood depths in Tennessee were derived using data for 150 gaging stations. The equations are based on drainage basin size and can be used to estimate depths of the 10-year and 100-year floods for four hydrologic areas. A method also was developed for estimating depth of floods having recurrence intervals between 10 and 100 years. Standard errors range from 22 to 30 percent for the 10-year depth equations and from 23 to 30 percent for the 100-year depth equations. (USGS)

Changing Perceptions of Flooding and Stormwater as a Driver of Urban Hydrology and Biogeochemistry

NASA Astrophysics Data System (ADS)

Hale, R. L.

2015-12-01

Urbanization can have detrimental impacts on downstream ecosystems due to its effects on hydrological and biogeochemical cycles. In particular, how urban stormwater systems are designed have implications for flood regimes and biogeochemical transformations. Flood and stormwater management paradigms have shifted over time at large scales, but patterns and drivers of local stormwater infrastructure designs are unknown. We describe patterns of infrastructure design and use over the 20th century in three cities along an urbanization gradient in Utah: Salt Lake, Logan, and Heber City. To understand changes in stormwater management paradigms we conducted a historical media content analysis of newspaper articles related to flooding and stormwater in Salt Lake City from 1900 to 2012. Stormwater infrastructure design varied spatially and temporally, both within and among cities. All three cities transitioned from agriculture to urban land use, and legacies were evident in the use of agricultural canals for stormwater conveyance. Salt Lake City infrastructure transitioned from centralized storm sewers during early urbanization to decentralized detention systems in the 1970's. In contrast, newer cities, Logan and Heber, saw parallel increases in conveyance and detention systems with urbanization. The media analysis revealed significant changes in flood and stormwater management paradigms over the 20th century that were driven by complex factors including top-down regulations, local disturbances, and funding constraints. Early management paradigms focused on infrastructural solutions to address problems with private and public property damage, whereas more recent paradigms focus on behavioral solutions to flooding and green infrastructure solutions to prevent negative impacts of urban stormwater on local ecosystems. Changes in human perceptions of the environment can affect how we design urban ecosystems, with important implications for ecological functions.

Digital technologies in support of flood resilience: A case study from Nepal

NASA Astrophysics Data System (ADS)

Liu, Wei; McCallum, Ian; See, Linda; Dugar, Sumit; Laso-Bayas, Juan-Carlos

2016-04-01

This paper presents ongoing efforts to support flood resilience in the Karnali basin in Nepal through the provision of different forms of digital technology. Flood Risk Geo-Wiki is an online visualization and crowdsourcing tool, which has been adapted to display flood risk maps at the global scale as well as information of relevance to planners and the community at the local level. Community-based flood risk maps, which have traditionally been drawn on paper, are being digitized and integrated with OpenStreetMap to provide better access to this collective knowledge base. Mobile phones, using the GeoODK (Geographical Open Data Kit) questionnaire builder, are being deployed to collect georeferenced information on flood risks and vulnerability, which can be used to validate flood models and design action plans and strategies for coping with future flood events. These types of digital technologies are simple to implement yet together can help support flood prone communities.

Methods for Estimating Magnitude and Frequency of Floods in Rural Basins in the Southeastern United States: South Carolina

USGS Publications Warehouse

Feaster, Toby D.; Gotvald, Anthony J.; Weaver, J. Curtis

2009-01-01

For more than 50 years, the U.S. Geological Survey (USGS) has been developing regional regression equations that can be used to estimate flood magnitude and frequency at ungaged sites. Flood magnitude relates to the volume of flow that occurs over some period of time and usually is presented in cubic feet per second. Flood frequency relates to the probability of occurrence of a flood; that is, on average, what is the likelihood that a flood with a specified magnitude will occur in any given year (1 percent chance, 10 percent chance, 50 percent chance, and so on). Such flood estimates are needed for the efficient design of bridges, highway embankments, levees, and other structures near streams. In addition, these estimates are needed for the effective planning and management of land and water resources, to protect lives and property in flood-prone areas, and to determine flood-insurance rates.

Evaluation of multiple hydraulic models in generating design/near-real time flood inundation extents under various geophysical settings

NASA Astrophysics Data System (ADS)

Liu, Z.; Rajib, M. A.; Jafarzadegan, K.; Merwade, V.

2015-12-01

Application of land surface/hydrologic models within an operational flood forecasting system can provide probable time of occurrence and magnitude of streamflow at specific locations along a stream. Creating time-varying spatial extent of flood inundation and depth requires the use of a hydraulic or hydrodynamic model. Models differ in representing river geometry and surface roughness which can lead to different output depending on the particular model being used. The result from a single hydraulic model provides just one possible realization of the flood extent without capturing the uncertainty associated with the input or the model parameters. The objective of this study is to compare multiple hydraulic models toward generating ensemble flood inundation extents. Specifically, relative performances of four hydraulic models, including AutoRoute, HEC-RAS, HEC-RAS 2D, and LISFLOOD are evaluated under different geophysical conditions in several locations across the United States. By using streamflow output from the same hydrologic model (SWAT in this case), hydraulic simulations are conducted for three configurations: (i) hindcasting mode by using past observed weather data at daily time scale in which models are being calibrated against USGS streamflow observations, (ii) validation mode using near real-time weather data at sub-daily time scale, and (iii) design mode with extreme streamflow data having specific return periods. Model generated inundation maps for observed flood events both from hindcasting and validation modes are compared with remotely sensed images, whereas the design mode outcomes are compared with corresponding FEMA generated flood hazard maps. The comparisons presented here will give insights on probable model-specific nature of biases and their relative advantages/disadvantages as components of an operational flood forecasting system.

Public Policy and Private Enterprise in the Development of Flood Plains: A Laboratory Exercise in Physical Geography

ERIC Educational Resources Information Center

Nunnally, Nelson R.; And Others

1974-01-01

This activity is designed to introduce college students to the concept of floods as natural hazards, to flood frequency analysis, to hazard adjustment, and to the mechanics of public policy formulation through a six hour laboratory exercise, culminating in a simulation game. (JH)

Planned flooding and Colorado River riparian trade-offs downstream from Glen Canyon Dam, Arizona

USGS Publications Warehouse

Stevens, Lawrence E.; Ayers, T.J.; Bennett, J.B.; Christensen, K.; Kearsley, M.J.C.; Meretsky, V.J.; Phillips, A. M.; Parnell, R.A.; Spence, J.; Sogge, M.K.; Springer, A.E.; Wegner, D.L.

2001-01-01

Regulated river restoration through planned flooding involves trade-offs between aquatic and terrestrial components, between relict pre-dam and novel post-dam resources and processes, and between management of individual resources and ecosystem characteristics. We review the terrestrial (wetland and riparian) impacts of a 1274 m3/s test flood conducted by the U.S. Bureau of Reclamation in March/April 1996, which was designed to improve understanding of sediment transport and management downstream from Glen Canyon Dam in the Colorado River ecosystem. The test flood successfully restored sandbars throughout the river corridor and was timed to prevent direct impacts to species of concern. A total of 1275 endangered Kanab ambersnail (Oxyloma haydeni kanabensis) were translocated above the flood zone at Vaseys Paradise spring, and an estimated 10.7% of the total snail habitat and 7.7% of the total snail population were lost to the flood. The test flood scoured channel margin wetlands, including potential foraging habitats of endangered Southwestern Willow Flycatcher (Empidonax traillii extimus). It also buried ground-covering riparian vegetation under >1 m of fine sand but only slightly altered woody sandbar vegetation and some return-current channel marshes. Pre-flood control efforts and appropriate flood timing limited recruitment of four common nonnative perennial plant species. Slight impacts on ethnobotanical resources were detected >430 km downstream, but those plant assemblages recovered rapidly. Careful design of planned flood hydrograph shape and seasonal timing is required to mitigate terrestrial impacts during efforts to restore essential fluvial geomorphic and aquatic habitats in regulated river ecosystems.

Urban flood risk mitigation: from vulnerability assessment to resilient city

NASA Astrophysics Data System (ADS)

Serre, D.; Barroca, B.

2009-04-01

Urban flood risk mitigation: from vulnerability assessment to resilient city Bruno Barroca1, Damien Serre2 1Laboratory of Urban Engineering, Environment and Building (L G U E H) - Université de Marne-la-Vallée - Pôle Ville, 5, Bd Descartes - Bâtiment Lavoisier - 77454 Marne la Vallée Cedex 2 - France 2City of Paris Engineering School, Construction - Environment Department, 15 rue Fénelon, 75010 Paris, France In France, as in Europe and more generally throughout the world, river floods have been increasing in frequency and severity over the last ten years, and there are more instances of rivers bursting their banks, aggravating the impact of the flooding of areas supposedly protected by flood defenses. Despite efforts made to well maintain the flood defense assets, we often observe flood defense failures leading to finally increase flood risk in protected area during major flood events. Furthermore, flood forecasting models, although they benefit continuous improvements, remain partly inaccurate due to uncertainties populated all along data calculation processes. These circumstances obliged stakeholders and the scientific communities to manage flood risk by integrating new concepts like stakes management, vulnerability assessments and more recently urban resilience development. Definitively, the goal is to reduce flood risk by managing of course flood defenses and improving flood forecasting models, but also stakes and vulnerability of flooded areas to achieve urban resilience face to flood events. Vulnerability to flood is essentially concentrated in urban areas. Assessing vulnerability of a city is very difficult. Indeed, urban area is a complex system composed by a sum of technical sub-systems as complex as the urban area itself. Assessing city vulnerability consists in talking into account each sub system vulnerability and integrating all direct and indirect impacts generally depending from city shape and city spatial organization. At this time, although some research activities have been undertaken, there are no specific methods and tools to assess flood vulnerability at the scale of the city. Indeed, by studying literature we can list some vulnerability indicators and a few Geographic Information System (GIS) tools. But generally indicators and GIS are not developed specifically at the city scale: often a regional scale is used. Analyzing vulnerability at this scale needs more accurate and formalized indicators and GIS tools. The second limit of existing GIS is temporal: even if vulnerability could be assessed and localized through GIS, such tools cannot assist city managers in their decision to efficiency recover after a severe flood event. Due to scale and temporal limits, methods and tools available to assess urban vulnerability need large improvements. Talking into account all these considerations and limits, our research is focusing on: • vulnerability indicators design; • recovery scenarios design; • GIS for city vulnerability assessment and recovery scenarios. Dealing with vulnerability indicators, the goal is to design a set of indicators of city sub systems. Sub systems are seen like assets of high value and complex and interdependent infrastructure networks (i.e. power supplies, communications, water, transport etc.). The infrastructure networks are critical for the continuity of economic activities as well as for the people's basic living needs. Their availability is also required for fast and effective recovery after flood disasters. The severity of flood damage therefore largely depends on the degree that both high value assets and critical urban infrastructure are affected, either directly or indirectly. To face the challenge of designing indicators, a functional model of the city system (and sub systems) has to be built to analyze the system response to flood solicitation. Then, a coherent and an efficient set of vulnerability of indicators could be built up. With such methods city stakeholders will be informed on how and how much their systems are vulnerable. It is a first level of information that has to be completed to become a real decision making tool. Indeed, we have seen that major floods cause almost always failures in the flood defense system. So potentially the city could face a flood event and managers recovery works. Knowing the vulnerability of the city, direct and indirect impacts, how can managers optimize recovery actions? Our research will focus first on proposing recovery scenarios based on the city system and second on vulnerability indicators to first limit damages during floods and to speed up recovery actions. At last, a GIS will be developed to assist stakeholders to take spatial measures to reduce city system weakness before a flood event and to help them to decide on how to optimize recovery actions after a flood event. Dealing with these two temporal scales will allow obtaining more flood resilient cities.

Street floods in Metro Manila and possible solutions.

PubMed

Lagmay, Alfredo Mahar; Mendoza, Jerico; Cipriano, Fatima; Delmendo, Patricia Anne; Lacsamana, Micah Nieves; Moises, Marc Anthony; Pellejera, Nicanor; Punay, Kenneth Niño; Sabio, Glenn; Santos, Laurize; Serrano, Jonathan; Taniza, Herbert James; Tingin, Neil Eneri

2017-09-01

Urban floods from thunderstorms cause severe problems in Metro Manila due to road traffic. Using Light Detection and Ranging (LiDAR)-derived topography, flood simulations and anecdotal reports, the root of surface flood problems in Metro Manila is identified. Majority of flood-prone areas are along the intersection of creeks and streets located in topographic lows. When creeks overflow or when rapidly accumulated street flood does not drain fast enough to the nearest stream channel, the intersecting road also gets flooded. Possible solutions include the elevation of roads or construction of well-designed drainage structures leading to the creeks. Proposed solutions to the flood problem of Metro Manila may avoid paralyzing traffic problems due to short-lived rain events, which according to Japan International Cooperation Agency (JICA) cost the Philippine economy 2.4billionpesos/day. Copyright © 2017. Published by Elsevier B.V.

A Bayesian Surrogate for Regional Skew in Flood Frequency Analysis

NASA Astrophysics Data System (ADS)

Kuczera, George

1983-06-01

The problem of how to best utilize site and regional flood data to infer the shape parameter of a flood distribution is considered. One approach to this problem is given in Bulletin 17B of the U.S. Water Resources Council (1981) for the log-Pearson distribution. Here a lesser known distribution is considered, namely, the power normal which fits flood data as well as the log-Pearson and has a shape parameter denoted by λ derived from a Box-Cox power transformation. The problem of regionalizing λ is considered from an empirical Bayes perspective where site and regional flood data are used to infer λ. The distortive effects of spatial correlation and heterogeneity of site sampling variance of λ are explicitly studied with spatial correlation being found to be of secondary importance. The end product of this analysis is the posterior distribution of the power normal parameters expressing, in probabilistic terms, what is known about the parameters given site flood data and regional information on λ. This distribution can be used to provide the designer with several types of information. The posterior distribution of the T-year flood is derived. The effect of nonlinearity in λ on inference is illustrated. Because uncertainty in λ is explicitly allowed for, the understatement in confidence limits due to fixing λ (analogous to fixing log skew) is avoided. Finally, it is shown how to obtain the marginal flood distribution which can be used to select a design flood with specified exceedance probability.

Two-Dimensional Simulation of Flow and Evaluation of Bridge Scour at Structure A-1700 on Interstate 155 over the Mississippi River near Caruthersville, Missouri

USGS Publications Warehouse

Huizinga, Richard J.

2007-01-01

The evaluation of scour at bridges throughout the State of Missouri has been ongoing since 1991, and most of these evaluations have used one-dimensional hydraulic analysis and application of conventional scour depth prediction equations. Occasionally, the complex conditions of a site dictate a more thorough assessment of the stream hydraulics beyond a one-dimensional model. This was the case for structure A-1700, the Interstate 155 bridge crossing the Mississippi River near Caruthersville, Missouri. To assess the complex hydraulics at this site, a two-dimensional hydrodynamic flow model was used to simulate flow conditions on the Mississippi River in the vicinity of the Interstate 155 structure A-1700. The model was used to simulate flow conditions for three discharges: a flood that occurred on April 4, 1975 (the calibration flood), which had a discharge of 1,658,000 cubic feet per second; the 100-year flood, which has a discharge of 1,960,000 cubic feet per second; and the project design flood, which has a discharge of 1,974,000 cubic feet per second. The project design flood was essentially equivalent to the flood that would cause impending overtopping of the mainline levees along the Mississippi River in the vicinity of structure A-1700. Discharge and river-stage readings from the flood of April 4, 1975, were used to calibrate the flow model. The model was then used to simulate the 100-year and project design floods. Hydraulic flow parameters obtained from the three flow simulations were applied to scour depth prediction equations to determine contraction, local pier, and abutment scour depths at structure A-1700. Contraction scour and local pier scour depths computed for the project design discharge generally were the greatest, whereas the depths computed for the calibration flood were the least. The maximum predicted total scour depth (contraction and local pier scour) for the calibration flood was 66.1 feet; for the 100-year flood, the maximum predicted total scour depth was 74.6 feet; for the project design flood, the maximum predicted total scour depth was 93.0 feet. If scour protection did not exist, bent 14 and piers 15 through 21 would be substantially exposed or undermined by the predicted total scour depths in all of the flood simulations. However, piers 18 through 21 have a riprap blanket around the base of each, and the riprap blanket observed on the right bank around bent 14 is thought to extend around the base of pier 15, which would limit the amount of scour that would occur at these piers. Furthermore, the footings and caissons that are not exposed by computed contraction scour may arrest local pier scour, which will limit local pier scour at several bents and piers. Nevertheless, main-channel piers 16 and 17 and all of the bents on the left (as viewed facing downstream) overbank are moderately to substantially exposed by the predicted scour depths from the three flood simulations, and there is no known scour protection at these piers or bents. Abutment scour depths were computed for structure A-1700, but abutment scour is expected to be mitigated by the presence of guidebanks upstream from the bridge abutments, as well as riprap revetment on the abutment and guidebank faces.

Comparison of floods non-stationarity detection methods: an Austrian case study

NASA Astrophysics Data System (ADS)

Salinas, Jose Luis; Viglione, Alberto; Blöschl, Günter

2016-04-01

Non-stationarities in flood regimes have a huge impact in any mid and long term flood management strategy. In particular the estimation of design floods is very sensitive to any kind of flood non-stationarity, as they should be linked to a return period, concept that can be ill defined in a non-stationary context. Therefore it is crucial when analyzing existent flood time series to detect and, where possible, attribute flood non-stationarities to changing hydroclimatic and land-use processes. This works presents the preliminary results of applying different non-stationarity detection methods on annual peak discharges time series over more than 400 gauging stations in Austria. The kind of non-stationarities analyzed include trends (linear and non-linear), breakpoints, clustering beyond stochastic randomness, and detection of flood rich/flood poor periods. Austria presents a large variety of landscapes, elevations and climates that allow us to interpret the spatial patterns obtained with the non-stationarity detection methods in terms of the dominant flood generation mechanisms.

Urban flood return period assessment through rainfall-flood response modelling

NASA Astrophysics Data System (ADS)

Murla Tuyls, Damian; Thorndahl, Søren

2017-04-01

Intense rainfall can often cause severe floods, especially in urbanized areas, where population density or large impermeable areas are found. In this context, floods can generate a direct impact in a social-environmental-economic viewpoint. Traditionally, in design of Urban Drainage Systems (UDS), correlation between return period (RP) of a given rainfall and RP of its consequent flood has been assumed to be linear (e.g. DS/EN752 (2008)). However, this is not always the case. Complex UDS, where diverse hydraulic infrastructures are often found, increase the heterogeneity of system response, which may cause an alteration of the mentioned correlation. Consequently, reliability on future urban planning, design and resilience against floods may be also affected by this misassumption. In this study, an assessment of surface flood RP across rainfall RP has been carried out at Lystrup, a urbanized catchment area of 440ha and 10.400inhab. located in Jutland (Denmark), which has received the impact of several pluvial flooding in the last recent years. A historical rainfall dataset from the last 35 years from two different rain gauges located at 2 and 10 km from the study area has been provided by the Danish Wastewater Pollution Committee and the Danish Meteorological Institute (DMI). The most extreme 25 rainfall events have been selected through a two-step multi-criteria procedure, ensuring an adequate variability of rainfall, from extreme high peak storms with a short duration to moderate rainfall with longer duration. In addition, a coupled 1D/2D surface and network UDS model of the catchment area developed in an integrated MIKE URBAN and MIKE Flood model (DHI 2014), considering both permeable and impermeable areas, in combination with a DTM (2x2m res.) has been used to study and assess in detail flood RP. Results show an ambiguous relation between rainfall RP and flood response. Local flood levels, flood area and volume RP estimates should therefore not be neglected in order to guarantee quality of the assessment, especially in design of complex UDS, where features as the main slope, hydraulic capacity, permeability, etc. can play an important role. In addition, a novel approach has been applied to map the response time (Tc) of the flood prone areas of the system under study. Together with the flood area and volume RP estimates this provides valuable knowledge suggesting to consider the different subareas of the UDS for design purposes and to establish a robust database that allows urban areas to be resilient against the severe impact of rainfall. Acknowledgement to ERA-NET Cofund Water Works 2014 (project MUFFIN) for the partial funding of this research; to the Danish Wastewater Pollution Committee and the Danish Meteorological Institute (DMI) for providing the rainfall dataset; to the Danish Geodata Agency for providing the DTM data and to DHI for providing license to MIKE software packages. The applied model has been made available for this study by Aarhus Water Utility Services. References DHI, 2014. MIKE by DHI software package 2014. Hørsholm, DK. DS/EN 752, 2008. Drain and sewer systems outside buildings.

Urban flood mitigation planning for Guwahati: A case of Bharalu basin.

PubMed

Sarmah, Tanaya; Das, Sutapa

2018-01-15

Guwahati, the capital city of Assam and the gateway to the seven north-eastern Indian states, is located in the Brahmaputra valley-one of the most flood prone regions of the world. The city receives an average annual rainfall of 1688 mm and is highly vulnerable towards frequent urban floods because of uncontrolled dumping of solid waste and siltation have choked the natural water channels. This coupled with the absence of an integrated drainage network and rapid urbanisation causes floods in many parts of the city, after a quick downpour. Bharalu river is the main natural water channel of the city and Bharalu basin is the most vulnerable one. The present paper is an attempt to plan for urban flood mitigation, by designing an integrated drainage network for the Bharalu basin which includes the low-lying urbanized areas bordered by the Guwahati-Shillong Road, the Radha Gobindo Baruah Road and the Rajgarh Road. Data regarding land use, flood level, rainfall, urban pattern and vulnerability towards urban flood were collected from available literature, field survey to find highest water level for 11.4 km road stretch, expert opinion survey from 18 experts and feedback from 77 community elders who have been residing in the city since the 1980s. The Bharalu basin is divided into seven drainage blocks and storm run-off has been calculated based on the inputs. Seven different trapezoidal drainage sections were designed to form an integrated drainage network which is 'self-healing' to a certain extent. This can serve as a template for the other catchment basins and to design a drainage network for the entire Guwahati city, thereby reducing urban flood hazard to a significant extent. The study illustrates the necessity of an urban flood mitigation planning approach in sub-Himalayan urban settlements such as Guwahati. Copyright © 2017 Elsevier Ltd. All rights reserved.

Catchment scale afforestation for mitigating flooding

NASA Astrophysics Data System (ADS)

Barnes, Mhari; Quinn, Paul; Bathurst, James; Birkinshaw, Stephen

2016-04-01

After the 2013-14 floods in the UK there were calls to 'forest the uplands' as a solution to reducing flood risk across the nation. At present, 1 in 6 homes in Britain are at risk of flooding and current EU legislation demands a sustainable, 'nature-based solution'. However, the role of forests as a natural flood management technique remains highly controversial, due to a distinct lack of robust evidence into its effectiveness in reducing flood risk during extreme events. SHETRAN, physically-based spatially-distributed hydrological models of the Irthing catchment and Wark forest sub-catchments (northern England) have been developed in order to test the hypothesis of the effect trees have on flood magnitude. The advanced physically-based models have been designed to model scale-related responses from 1, through 10, to 100km2, a first study of the extent to which afforestation and woody debris runoff attenuation features (RAFs) may help to mitigate floods at the full catchment scale (100-1000 km2) and on a national basis. Furthermore, there is a need to analyse the extent to which land management practices, and the installation of nature-based RAFs, such as woody debris dams, in headwater catchments can attenuate flood-wave movement, and potentially reduce downstream flood risk. The impacts of riparian planting and the benefits of adding large woody debris of several designs and on differing sizes of channels has also been simulated using advanced hydrodynamic (HiPIMS) and hydrological modelling (SHETRAN). With the aim of determining the effect forestry may have on flood frequency, 1000 years of generated rainfall data representative of current conditions has been used to determine the difference between current land-cover, different distributions of forest cover and the defining scenarios - complete forest removal and complete afforestation of the catchment. The simulations show the percentage of forestry required to have a significant impact on mitigating downstream flood risk at sub-catchment and catchment scale. Key words: Flood peak, nature-based solutions, forest hydrology, hydrological modelling, SHETRAN, flood frequency, flood magnitude, land-cover change, upland afforestation.

Flexibility in flood management design: proactive planning under uncertainty

NASA Astrophysics Data System (ADS)

Smet, K.; de Neufville, R.; van der Vlist, M.

2016-12-01

This paper presents a value-enhancing approach for proactive planning and design of long-lived flood management infrastructure given uncertain future flooding threats. Designing infrastructure that can be adapted over time is a method to safeguard the efficacy of current design decisions given future uncertainties. We explore the value of embedding "options" in a physical structure, where an option is the right but not the obligation to do something at a later date (e.g. over-dimensioning a floodwall foundation now facilitates a future height addition in response to observed increases in sea level; building extra pump bays in a drainage pumping station enables the easy addition of pumping capacity whenever increased precipitation warrants an expansion.) The proposed approach couples a simulation model that captures future climate induced changes to the hydrologic operating environment of a structure, with an economic model that estimates the lifetime economic performance of alternative investment strategies. The economic model uses Real "In" Options analysis, a type of cash flow analysis that quantifies the implicit value of options and the flexibility they provide. We demonstrate the approach using replacement planning for the multi-functional pumping station IJmuiden on the North Sea Canal in the Netherlands. The analysis models flexibility in design decisions, varying the size and specific options included in the new structure. Results indicate that the incorporation of options within the structural design has the potential to improve its economic performance, as compared to more traditional, "build it once and build it big" designs where flexibility is not an explicit design criterion. The added value resulting from the incorporation of flexibility varies with the range of future conditions considered, and the specific options examined. This approach could be applied to explore investment strategies for the design of other flood management structures, as well as be expanded to look more at flexibility within an infrastructure network rather than a single structure. Flexibility in flood management design:proactive planning under uncertainty

Techniques for estimating flood hydrographs for ungaged urban watersheds

USGS Publications Warehouse

Stricker, V.A.; Sauer, V.B.

1984-01-01

The Clark Method, modified slightly was used to develop a synthetic, dimensionless hydrograph which can be used to estimate flood hydrographs for ungaged urban watersheds. Application of the technique results in a typical (average) flood hydrograph for a given peak discharge. Input necessary to apply the technique is an estimate of basin lagtime and the recurrence interval peak discharge. Equations for this purpose were obtained from a recent nationwide study on flood frequency in urban watersheds. A regression equation was developed which relates flood volumes to drainage area size, basin lagtime, and peak discharge. This equation is useful where storage of floodwater may be a part of design of flood prevention. (USGS)

Flood profiles in the Calapooya Creek basin, Oregon

USGS Publications Warehouse

Friday, John

1982-01-01

Water-surface profiles were computed for a 19.4-mile reach of Calapooya Creek in Douglas County, Oregon. The data will enable the county to evaluate flood hazards in the floodprone areas in the reach. Profiles for floods having recurrence intervals of 2, 10, 50, 100, and 500 years are shown in graphic and tabular form. A floodway, allowing encroachment of the 100-year floods, was designed with a maximum 1.0-foot surcharge limitation. A profile for a flood that occurred in November 1961 is also presented. All data were derived from a digital computer model developed for the study.

Establishment and Practical Application of Flood Warning Stage in Taiwan's River

NASA Astrophysics Data System (ADS)

Yang, Sheng-Hsueh; Chia Yeh, Keh-

2017-04-01

In the face of extreme flood events or the possible impact of climate change, non-engineering disaster prevention and early warning work is particularly important. Taiwan is an island topography with more than 3,900 meters of high mountains. The length of the river is less than 100 kilometers. Most of the watershed catchment time is less than 24 hours, which belongs to the river with steep slope and rapid flood. Every year in summer and autumn, several typhoon events invade Taiwan. Typhoons often result in rainfall events in excess of 100 mm/hr or 250 mm/3hr. In the face of Taiwan's terrain and extreme rainfall events, flooding is difficult to avoid. Therefore, most of the river has embankment protection, so that people do not have to face every year flooding caused by economic and life and property losses. However, the river embankment protection is limited. With the increase of the hydrological data, the design criteria for the embankment protection standards in the past was 100 year of flood return period and is now gradually reduced to 25 or 50 year of flood return period. The river authorities are not easy to rise the existing embankment height. The safety of the river embankment in Taiwan is determined by the establishment of the flood warning stage to cope with the possible increase in annual floods and the impact of extreme hydrological events. The flood warning stage is equal to the flood control elevation minus the flood rise rate multiply by the flood early warning time. The control elevation can be the top of the embankment, the design flood level of the river, the embankment gap of the river section, the height of the bridge beam bottom, etc. The flood rise rate is consider the factors such as hydrological stochastic and uncertain rainfall and the effect of flood discharge operation on the flood in the watershed catchment area. The maximum value of the water level difference between the two hours or five hours before the peak value of the analysis result is decided by this rate. The flood early warning time is divided into two levels, the first level is 2 hours, evacuation time for the public, the second level is 5 hours for the implementation of unit preparation time. Finally, The flood warning stages are practical application in 20 water level stations have been incorporated into the flood early warning system of the Danshuei river basin in Taiwan.

Improving flood risk management through risk communication strategies

NASA Astrophysics Data System (ADS)

Bodoque, Jose Maria; Diez Herrero, Andres; Amerigo, Maria; Garcia, Juan Antonio; Olcina, Jorge; Cortes, Beatriz

2016-04-01

A suitable level of social perception about flood risk and awareness of Civil Protection Plans are critical to minimize disasters and damages due to flash floods. In order to improve risk perception, awareness and, as a result, the effectiveness of Civil Protection Plans, it is often required the implementation of communication plans. This research proposes a guide recommendation framework to enhance local population preparedness, prevention and response when a flash flood occurs. The research setting was a village (Navaluenga) located in Central Spain with 2,027 inhabitants. It is crossed by the Alberche river and Chorreron stream (both tributaries of the Tagus river), which are prone to flash floods. In a first phase, we assessed citizens' flash-flood risk perception and level of awareness regarding some key variables of the Civil Protection Plan. To this end, a questionnaire survey was designed and 254 adults, a sample representing roughly 12% of the population census, were interviewed. Responses were analysed, comparing awareness regarding preparedness and response actions with those previously defined in the Civil Protection Plan. In addition, we carried out a latent class cluster analysis aimed at identifying the different groups present among the respondents. Next, a risk communication plan was designed and implemented. It aimed to improve the understanding of flood risk among local people; and it comprises briefings, quiz-answers, contests of stories and flood images and intergenerational workshops. Finally, participants in the first phase were reached again and a new survey was performed. The results derived from these second questionnaires were statistically treated using the same approach of the first phase. Additionally, a t-test for paired samples and Pearson Chi-Square test was implemented in order to detect possible improvements in the perception and awareness. Preliminary results indicate that in Navaluenga there is a low social perception of flood risk and a low level of awareness regarding the Civil Protection Plan. In the social context of the Iberian Peninsula, where climate change models indicate an increase in extreme weather events and, consequently, high exposure and vulnerability to flash floods, the implementation of appropriately designed communication strategies is critical to improve the resilience of urban areas in order to cope with this risk.

A restatement of the natural science evidence concerning catchment-based `natural' flood management in the UK

NASA Astrophysics Data System (ADS)

Dadson, Simon J.; Hall, Jim W.; Murgatroyd, Anna; Acreman, Mike; Bates, Paul; Beven, Keith; Heathwaite, Louise; Holden, Joseph; Holman, Ian P.; Lane, Stuart N.; O'Connell, Enda; Penning-Rowsell, Edmund; Reynard, Nick; Sear, David; Thorne, Colin; Wilby, Rob

2017-03-01

Flooding is a very costly natural hazard in the UK and is expected to increase further under future climate change scenarios. Flood defences are commonly deployed to protect communities and property from flooding, but in recent years flood management policy has looked towards solutions that seek to mitigate flood risk at flood-prone sites through targeted interventions throughout the catchment, sometimes using techniques which involve working with natural processes. This paper describes a project to provide a succinct summary of the natural science evidence base concerning the effectiveness of catchment-based `natural' flood management in the UK. The evidence summary is designed to be read by an informed but not technically specialist audience. Each evidence statement is placed into one of four categories describing the nature of the underlying information. The evidence summary forms the appendix to this paper and an annotated bibliography is provided in the electronic supplementary material.

A restatement of the natural science evidence concerning catchment-based 'natural' flood management in the UK.

PubMed

Dadson, Simon J; Hall, Jim W; Murgatroyd, Anna; Acreman, Mike; Bates, Paul; Beven, Keith; Heathwaite, Louise; Holden, Joseph; Holman, Ian P; Lane, Stuart N; O'Connell, Enda; Penning-Rowsell, Edmund; Reynard, Nick; Sear, David; Thorne, Colin; Wilby, Rob

2017-03-01

Flooding is a very costly natural hazard in the UK and is expected to increase further under future climate change scenarios. Flood defences are commonly deployed to protect communities and property from flooding, but in recent years flood management policy has looked towards solutions that seek to mitigate flood risk at flood-prone sites through targeted interventions throughout the catchment, sometimes using techniques which involve working with natural processes. This paper describes a project to provide a succinct summary of the natural science evidence base concerning the effectiveness of catchment-based 'natural' flood management in the UK. The evidence summary is designed to be read by an informed but not technically specialist audience. Each evidence statement is placed into one of four categories describing the nature of the underlying information. The evidence summary forms the appendix to this paper and an annotated bibliography is provided in the electronic supplementary material.

78 FR 48912 - Agency Information Collection Activities: Submission to OMB for Reinstatement, With Change, of a...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-12

... insured credit union granting a real estate loan to determine if flood insurance for the designated loan... credit union must determine if a real estate loan requires flood insurance for the designated loan term... 760. Respondents: Federally insured credit unions granting real estate loans. Total Estimated No. of...

Pittsfield Local Flood Protection, West Branch and Southwest Branch, Housatonic River, Pittsfield, Massachusetts. Detailed Project Report for Water Resources Development.

DTIC Science & Technology

1980-10-01

a bakery , a gas station, and the Linden Street bridge were flooded during the March 1977 storm. Flooding also occurred on the Southwest Branch...and service station, one bakery , and five other commercial establishments. Most of these structures are not suited to being elevated above the design...of a shopping plaza and a fast-food franchise in the flood plain on West Housatonic Street (Route 20). The following three alternate plans of

The Importance of Studying Past Extreme Floods to Prepare for Uncertain Future Extremes

NASA Astrophysics Data System (ADS)

Burges, S. J.

2016-12-01

Hoyt and Langbein, 1955 in their book `Floods' wrote: " ..meteorologic and hydrologic conditions will combine to produce superfloods of unprecedented magnitude. We have every reason to believe that in most rivers past floods may not be an accurate measure of ultimate flood potentialities. It is this superflood with which we are always most concerned". I provide several examples to offer some historical perspective on assessing extreme floods. In one example, flooding in the Miami Valley, OH in 1913 claimed 350 lives. The engineering and socio-economic challenges facing the Morgan Engineering Co in how to mitigate against future flood damage and loss of life when limited information was available provide guidance about ways to face an uncertain hydroclimate future, particularly one of a changed climate. A second example forces us to examine mixed flood populations and illustrates the huge uncertainty in assigning flood magnitude and exceedance probability to extreme floods in such cases. There is large uncertainty in flood frequency estimates; knowledge of the total flood hydrograph, not the peak flood flow rate alone, is what is needed for hazard mitigation assessment or design. Some challenges in estimating the complete flood hydrograph in an uncertain future climate, including demands on hydrologic models and their inputs, are addressed.

Participatory approaches to understanding practices of flood management across borders

NASA Astrophysics Data System (ADS)

Bracken, L. J.; Forrester, J.; Oughton, E. A.; Cinderby, S.; Donaldson, A.; Anness, L.; Passmore, D.

2012-04-01

The aim of this paper is to outline and present initial results from a study designed to identify principles of and practices for adaptive co-management strategies for resilience to flooding in borderlands using participatory methods. Borderlands are the complex and sometimes undefined spaces existing at the interface of different territories and draws attention towards messy connections and disconnections (Strathern 2004; Sassen 2006). For this project the borderlands concerned are those between professional and lay knowledge, between responsible agencies, and between one nation and another. Research was focused on the River Tweed catchment, located on the Scottish-English border. This catchment is subject to complex environmental designations and rural development regimes that make integrated management of the whole catchment difficult. A multi-method approach was developed using semi-structured interviews, Q methodology and participatory GIS in order to capture wide ranging practices for managing flooding, the judgements behind these practices and to 'scale up' participation in the study. Professionals and local experts were involved in the research. The methodology generated a useful set of options for flood management, with research outputs easily understood by key management organisations and the wider public alike. There was a wide endorsement of alternative flood management solutions from both managers and local experts. The role of location was particularly important for ensuring communication and data sharing between flood managers from different organisations and more wide ranging stakeholders. There were complex issues around scale; both the mismatch between communities and evidence of flooding and the mismatch between governance and scale of intervention for natural flood management. The multi-method approach was essential in capturing practice and the complexities around governance of flooding. The involvement of key flood management organisations was integral to making the research of relevance to professionals.

Evaluating the anthropogenic impacts on fluvial flood risks in a coastal mega-city during its transitional economy (1979-2009): the interaction between land subsidence, urbanization and structural measures

NASA Astrophysics Data System (ADS)

Yu, Dapeng; Yin, Jie

2014-05-01

Flood risk in a specific geographical location is a function of the interaction between various natural (e.g. rainfall, sea-level rise) and anthropogenic processes (e.g. land subsidence and urbanization). These processes, whether a driver or an alleviating factor, often encompass a large degree of spatial and temporal variability. Looking at a specific process in isolation is likely to provide an incomplete picture of the risks. This paper describes a novel approach to the evaluation of anthropogenic impacts on flood risks in coastal mega-cities by incorporating three anthropogenic variables (land subsidence, urbanization and flood defence) within a scenario-based framework where numerical modelling was undertaken to quantify the risks. The evolving risks at four time points (1979, 1990, 2000 and 2009) were assessed for the Huangpu River floodplain where the City of Shanghai is located. Distributed data of land subsidence rate, urbanization rate and flood defence heights were obtained. Scenarios were designed by representing the rate of land subsidence and flood defence height through the modification of DEM. Effect of urbanization is represented by a roughness parameter in the model simulations. A 2D hydrodynamic model (FloodMap-Inertial) was used to estimate the flood risks associated with each scenario. Flood events with various return periods (10-, 100- and 1000-year) were designed based on a one in 50 year flood event occurred in Shanghai in August 1997. Results demonstrate the individual as well as the combined impacts of the three anthropogenic factors on the changing fluvial flood risks in the Huangpu River basin over the last three decades during the city's transitional economy (1979-2009). Land subsidence and urbanization were found to lead to proportionate but non-linear impact on flood risks due to their complex spatial and temporal interaction. The impacts and their sensitivity are the function of the rate & spatial distribution of each evolving factor. They also manifest differently in floods of different magnitude. While the pattern of response to individual anthropogenic variables is largely expected, the combined impacts demonstrate greater spatial and temporal variation. Flood defences offer considerable benefits in reducing the total inundated areas in the Huangpu River basin over the periods considered, for all magnitude floods. This, to a large extent, alleviates the adverse impacts arising from land subsidence and urbanization. However, even with an enclosed and completed defence system in 2009, extensive flood inundation is still expected for a 10-year event, albeit largely restricted to the upstream of the river where urban settlements are limited. The scenario-based approach described herein could be adopted for applications in other urbanized and subsided coastal floodplains, especially in places where the rate of land subsidence is still accelerating, urbanization is still undergoing and the local sea level keeps rising. Risk scenarios that encompass probable future anthropogenic projections may assist decision makers and other concerned stakeholders in better understanding the underlying drivers of changing flood risks, and thus help to design proper adaptation options for sustainable flood risk management and urban planning.

23 CFR 650.111 - Location hydraulic studies.

Code of Federal Regulations, 2011 CFR

2011-04-01

... BRIDGES, STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains § 650... part 771. (f) Local, State, and Federal water resources and flood-plain management agencies should be...

23 CFR 650.111 - Location hydraulic studies.

Code of Federal Regulations, 2014 CFR

2014-04-01

... BRIDGES, STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains § 650... part 771. (f) Local, State, and Federal water resources and flood-plain management agencies should be...

23 CFR 650.111 - Location hydraulic studies.

Code of Federal Regulations, 2012 CFR

2012-04-01

... BRIDGES, STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains § 650... part 771. (f) Local, State, and Federal water resources and flood-plain management agencies should be...

23 CFR 650.111 - Location hydraulic studies.

Code of Federal Regulations, 2013 CFR

2013-04-01

... BRIDGES, STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains § 650... part 771. (f) Local, State, and Federal water resources and flood-plain management agencies should be...

23 CFR 650.111 - Location hydraulic studies.

Code of Federal Regulations, 2010 CFR

2010-04-01

... BRIDGES, STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains § 650... part 771. (f) Local, State, and Federal water resources and flood-plain management agencies should be...

Dynamic building risk assessment theoretic model for rainstorm-flood utilization ABM and ABS

NASA Astrophysics Data System (ADS)

Lai, Wenze; Li, Wenbo; Wang, Hailei; Huang, Yingliang; Wu, Xuelian; Sun, Bingyun

2015-12-01

Flood is one of natural disasters with the worst loss in the world. It needs to assess flood disaster risk so that we can reduce the loss of flood disaster. Disaster management practical work needs the dynamic risk results of building. Rainstorm flood disaster system is a typical complex system. From the view of complex system theory, flood disaster risk is the interaction result of hazard effect objects, rainstorm flood hazard factors, and hazard environments. Agent-based modeling (ABM) is an important tool for complex system modeling. Rainstorm-flood building risk dynamic assessment method (RFBRDAM) was proposed using ABM in this paper. The interior structures and procedures of different agents in proposed meth had been designed. On the Netlogo platform, the proposed method was implemented to assess the building risk changes of the rainstorm flood disaster in the Huaihe River Basin using Agent-based simulation (ABS). The results indicated that the proposed method can dynamically assess building risk of the whole process for the rainstorm flood disaster. The results of this paper can provide one new approach for flood disaster building risk dynamic assessment and flood disaster management.

An overview of road damages due to flooding: Case study in Kedah state, Malaysia

NASA Astrophysics Data System (ADS)

Ismail, Muhd Shahril Nizam; Ghani, Abdul Naser Abdul

2017-10-01

Flooding occurs frequently in many countries including Malaysia. Floods in Malaysia are usually due to heavy and prolonged rainfall, uncontrolled development, and drainage systems that are not being monitored. Road damage due to flooding event can cause huge expenditures for the post-flooding rehabilitation and maintenance. The required maintenance and rehabilitation could upset the original life cycle cost estimations. Data on road statistics were obtained from the Highway Planning Division, Ministry of Works Malaysia and data on flooding was collected from the Department of Irrigation and Drainage Malaysia for events between 2012 and 2015. The pilot sites were selected based on its historical cases of floods that caused road damages in Kedah. The pilot site indicated that the impact of flooding on road infrastructures systems can be used to plan better road design and maintenances. It also revealed that it costs more than RM 1 million to reinstate roads damaged by flooding in a typical district annually.

77 FR 56669 - Proposed Flood Hazard Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-13

...Comments are requested on proposed flood hazard determinations, which may include additions or modifications of any Base Flood Elevation (BFE), base flood depth, Special Flood Hazard Area (SFHA) boundary or zone designation, or regulatory floodway on the Flood Insurance Rate Maps (FIRMs), and where applicable, in the supporting Flood Insurance Study (FIS) reports for the communities listed in the table below. The purpose of this notice is to seek general information and comment regarding the preliminary FIRM, and where applicable, the FIS report that the Federal Emergency Management Agency (FEMA) has provided to the affected communities. The FIRM and FIS report are the basis of the floodplain management measures that the community is required either to adopt or to show evidence of having in effect in order to qualify or remain qualified for participation in the National Flood Insurance Program (NFIP). In addition, the FIRM and FIS report, once effective, will be used by insurance agents and others to calculate appropriate flood insurance premium rates for new buildings and the contents of those buildings.

Flooding risks: a comparison of lay people's perceptions and expert's assessments in Switzerland.

PubMed

Siegrist, Michael; Gutscher, Heinz

2006-08-01

Experts on the risk of flooding have developed very detailed maps for different parts of Switzerland that indicate the types of damage possible and the probabilities of adverse events. Four categories of risk severity are defined on the maps, ranging from high risk to no risk. Based on these existing maps, we selected respondents for a mail survey, some from areas high in risk and others from low-risk regions. Respondents answered several questions related to flood risk perception and preparedness. Survey results showed that respondents' risk perceptions were correlated with the experts' risk assessments. Respondents who lived in areas designated "no risk" by the experts had lower perceptions of risk than respondents who lived in areas with higher levels of designated risk. With regard to concrete prevention behavior, no differences between people living in different risk areas were observed. Survey results further suggest that many inhabitants do not know that flooding maps exist for their region. Results suggest that in some regions people overestimate the risks associated with flooding. Consequently, some people are more afraid of flooding than is justified by the facts. Some people show prevention behavior that most likely is superfluous. However, in other regions people underestimate the risks associated with flooding. These people do not show prevention behavior, and they are not well prepared for an adverse event. Furthermore, results suggest that respondents' experiences with flooding are positively related to their perceptions of flood risk. Findings of the present study are in line with the availability heuristic.

Effect of Sampling Period on Flood Frequency Distributions in the Susquehanna Basin

NASA Astrophysics Data System (ADS)

Kargar, M.; Beighley, R. E.

2010-12-01

Flooding is a devastating natural hazard that claims many human lives and significantly impact regional economies each year. Given the magnitude of flooding impacts, significant resources are dedicated to the development of forecasting models for early warning and evacuation planning, construction of flood defenses (levees/dams) to limit flooding, and the design of civil infrastructure (bridges, culverts, storm sewers) to convey flood flows without failing. In all these cases, it is particularly important to understand the potential flooding risk in terms of both recurrence interval (i.e., return period) and magnitude. Flood frequency analysis (FFA) is a form of risk analysis used to extrapolate the return periods of floods beyond the gauged record. The technique involves using observed annual peak flow discharge data to calculate statistical information such as mean values, standard deviations, skewness, and recurrence intervals. Since discharge data for most catchments have been collected for periods of time less than 100 years, the estimation of the design discharge requires a degree of extrapolation. This study focuses on the assessment and modifications of flood frequency based discharges for sites with limited sampling periods. Here, limited sampling period is intended to capture two issues: (1) limited number of observations to adequately capture the flood frequency signal (i.e., minimum number of annual peaks needed) and (2) climate variability (i.e., sampling period contains primarily “wet” or “dry” periods only). Total of 34 gauges (more than 70 years of data) spread throughout the Susquehanna River basin (71,000 sq km) were used to investigate the impact of sampling period on flood frequency distributions. Data subsets ranging from 10 years to the total number of years available were created from the data for each gauging station. To estimate the flood frequency, the Log Pearson Type III distribution was fit to the logarithms of instantaneous annual peak flows following Bulletin 17B guidelines of the U.S. Interagency Advisory Committee on Water Data. The resulting flood frequencies from these subsets were compared to the results from the entire record at each gauge. Based on the analysis, the minimum number of years required to obtain a reasonable flood frequency distribution was determined for each gauge. In addition, a method to adjust flood frequency distribution at a given gauging station with limited data based on other locations with longer periods of records was developed.

Floodflow characteristics at proposed bridge site on Fishkill Creek, Fishkill, New York

USGS Publications Warehouse

Zembrzuski, Thomas J.; Dunn, Bernard

1976-01-01

An evaluation of floodflow characteristics of Fishkill Creek at the proposed bridge site at Fishkill, N.Y., was made for the 50- and 100-year floods. The flood-frequency analysis revealed that the magnitude of the 50- and 100-year floods are 8,000 cubic feet per second (cfs) and 10,000 cfs, respectively. The normal water-surface elevation at the approach cross section was determined by the slope-conveyance method to be 209.8 feet during a 50-year flood and 210.8 feet during a 100-year flood. Also included is an analysis of the effect of the existing bridge and of two alternative bridge designs on the profiles of floods having recurrence intervals of 50 and 100 years. (Woodard-USGS)

Conceptualization of a Collaborative Decision Making for Flood Disaster Management

NASA Astrophysics Data System (ADS)

Nur Aishah Zubir, Siti; Thiruchelvam, Sivadass; Nasharuddin Mustapha, Kamal; Che Muda, Zakaria; Ghazali, Azrul; Hakimie, Hazlinda; Razak, Normy Norfiza Abdul; Aziz Mat Isa, Abdul; Hasini, Hasril; Sahari, Khairul Salleh Mohamed; Mat Husin, Norhayati; Ezanee Rusli, Mohd; Sabri Muda, Rahsidi; Mohd Sidek, Lariyah; Basri, Hidayah; Tukiman, Izawati

2016-03-01

Flooding is the utmost major natural hazard in Malaysia in terms of populations affected, frequency, area extent, flood duration and social economic damage. The recent flood devastation towards the end of 2014 witnessed almost 250,000 people being displaced from eight states in Peninsular Malaysia. The affected victims required evacuation within a short period of time to the designated evacuation centres. An effective and efficient flood disaster management would assure non-futile efforts for life-saving. Effective flood disaster management requires collective and cooperative emergency teamwork from various government agencies. Intergovernmental collaborations among government agencies at different levels have become part of flood disaster management due to the need for sharing resources and coordinating efforts. Collaborative decision making during disaster is an integral element in providing prompt and effective response for evacuating the victims.

Risk-based zoning for urbanizing floodplains.

PubMed

Porse, Erik

2014-01-01

Urban floodplain development brings economic benefits and enhanced flood risks. Rapidly growing cities must often balance the economic benefits and increased risks of floodplain settlement. Planning can provide multiple flood mitigation and environmental benefits by combining traditional structural measures such as levees, increasingly popular landscape and design features (green infrastructure), and non-structural measures such as zoning. Flexibility in both structural and non-structural options, including zoning procedures, can reduce flood risks. This paper presents a linear programming formulation to assess cost-effective urban floodplain development decisions that consider benefits and costs of development along with expected flood damages. It uses a probabilistic approach to identify combinations of land-use allocations (residential and commercial development, flood channels, distributed runoff management) and zoning regulations (development zones in channel) to maximize benefits. The model is applied to a floodplain planning analysis for an urbanizing region in the Baja Sur peninsula of Mexico. The analysis demonstrates how (1) economic benefits drive floodplain development, (2) flexible zoning can improve economic returns, and (3) cities can use landscapes, enhanced by technology and design, to manage floods. The framework can incorporate additional green infrastructure benefits, and bridges typical disciplinary gaps for planning and engineering.

A fast method for optical simulation of flood maps of light-sharing detector modules.

PubMed

Shi, Han; Du, Dong; Xu, JianFeng; Moses, William W; Peng, Qiyu

2015-12-01

Optical simulation of the detector module level is highly desired for Position Emission Tomography (PET) system design. Commonly used simulation toolkits such as GATE are not efficient in the optical simulation of detector modules with complicated light-sharing configurations, where a vast amount of photons need to be tracked. We present a fast approach based on a simplified specular reflectance model and a structured light-tracking algorithm to speed up the photon tracking in detector modules constructed with polished finish and specular reflector materials. We simulated conventional block detector designs with different slotted light guide patterns using the new approach and compared the outcomes with those from GATE simulations. While the two approaches generated comparable flood maps, the new approach was more than 200-600 times faster. The new approach has also been validated by constructing a prototype detector and comparing the simulated flood map with the experimental flood map. The experimental flood map has nearly uniformly distributed spots similar to those in the simulated flood map. In conclusion, the new approach provides a fast and reliable simulation tool for assisting in the development of light-sharing-based detector modules with a polished surface finish and using specular reflector materials.

Flood design recipes vs. reality: can predictions for ungauged basins be trusted?

NASA Astrophysics Data System (ADS)

Efstratiadis, A.; Koussis, A. D.; Koutsoyiannis, D.; Mamassis, N.

2014-06-01

Despite the great scientific and technological advances in flood hydrology, everyday engineering practices still follow simplistic approaches that are easy to formally implement in ungauged areas. In general, these "recipes" have been developed many decades ago, based on field data from typically few experimental catchments. However, many of them have been neither updated nor validated across all hydroclimatic and geomorphological conditions. This has an obvious impact on the quality and reliability of hydrological studies, and, consequently, on the safety and cost of the related flood protection works. Preliminary results, based on historical flood data from Cyprus and Greece, indicate that a substantial revision of many aspects of flood engineering procedures is required, including the regionalization formulas as well as the modelling concepts themselves. In order to provide a consistent design framework and to ensure realistic predictions of the flood risk (a key issue of the 2007/60/EU Directive) in ungauged basins, it is necessary to rethink the current engineering practices. In this vein, the collection of reliable hydrological data would be essential for re-evaluating the existing "recipes", taking into account local peculiarities, and for updating the modelling methodologies as needed.

Paleohydrology of flash floods in small desert watersheds in western Arizona

NASA Astrophysics Data System (ADS)

House, P. Kyle; Baker, Victor R.

2001-06-01

In this study, geological, historical, and meteorological data were combined to produce a regional chronology of flood magnitude and frequency in nine small basins (7-70 km2). The chronology spans more than 1000 years and demonstrates that detailed records of flood magnitude and frequency can be compiled in arid regions with little to no conventional hydrologic information. The recent (i.e., post-1950) flood history was evaluated by comparing a 50-year series of aerial photographs with precipitation data, ages of flood-transported beer cans, anthropogenic horizons in flood sediments, postbomb 14C dates on flotsam, and anecdotal accounts. Stratigraphic analysis of paleoflood deposits extended the regional flood record in time, and associated flood magnitudes were determined by incorporating relict high-water evidence into a hydraulic model. The results reveal a general consistency among the magnitudes of the largest floods in the historical and the paleoflood records and indicate that the magnitudes and relative frequencies of actual large floods are at variance with "100-year" flood magnitudes predicted by regional flood frequency models. This suggests that the predictive equations may not be appropriate for regulatory, management, or design purposes in the absence of additional, real data on flooding. Augmenting conventional approaches to regional flood magnitude and frequency analysis with real information derived from the alternative methods described here is a viable approach to improving assessments of regional flood characteristics in sparsely gaged desert areas.

Germany wide seasonal flood risk analysis for agricultural crops

NASA Astrophysics Data System (ADS)

Klaus, Stefan; Kreibich, Heidi; Kuhlmann, Bernd; Merz, Bruno; Schröter, Kai

2016-04-01

In recent years, large-scale flood risk analysis and mapping has gained attention. Regional to national risk assessments are needed, for example, for national risk policy developments, for large-scale disaster management planning and in the (re-)insurance industry. Despite increasing requests for comprehensive risk assessments some sectors have not received much scientific attention, one of these is the agricultural sector. In contrast to other sectors, agricultural crop losses depend strongly on the season. Also flood probability shows seasonal variation. Thus, the temporal superposition of high flood susceptibility of crops and high flood probability plays an important role for agricultural flood risk. To investigate this interrelation and provide a large-scale overview of agricultural flood risk in Germany, an agricultural crop loss model is used for crop susceptibility analyses and Germany wide seasonal flood-frequency analyses are undertaken to derive seasonal flood patterns. As a result, a Germany wide map of agricultural flood risk is shown as well as the crop type most at risk in a specific region. The risk maps may provide guidance for federal state-wide coordinated designation of retention areas.

The August 1975 Flood over Central China

NASA Astrophysics Data System (ADS)

Yang, Long; Smith, James; Liu, Maofeng; Baeck, MaryLynn

2016-04-01

The August 1975 flood in Central China was one of the most destructive floods in history, resulting in 26 000 fatalities, leaving about 10 million people with insufficient shelter, and producing long-lasting famine and disease. Extreme rainfall responsible for this flood event was associated with typhoon Nina during 5-7 August 1975. Despite the prominence of the August 1975 flood, analyses of the storms producing the flood and the resulting flood are sparse. Even fewer attempts were made from the perspective of numerical simulations. We examine details of extreme rainfall for the August 1975 flood based on downscaling simulations using the Weather Research and Forecasting (WRF) model driven by 20th Century Reanalysis fields. We further placed key hydrometeorological features for the flood event in a climatological context through the analyses of the 20th Century Reanalysis fields. Results indicate interrelated roles of multiple mesoscale ingredients for deep, moist convection in producing extreme rainfall for the August 1975 flood, superimposed over an anomalous synoptic environment. Attribution analyses on the source of water vapor for this flood event will be conducted based on a Lagrangian parcel tracking algorithm LAGRANTO. Analytical framework developed in this study aims to explore utilization of hydrometeorological approach in flood-control engineering designs by providing details on key elements of flood-producing storms.

Analysis of regional natural flow for evaluation of flood risk according to RCP climate change scenarios

NASA Astrophysics Data System (ADS)

Lee, J. Y.; Chae, B. S.; Wi, S.; KIm, T. W.

2017-12-01

Various climate change scenarios expect the rainfall in South Korea to increase by 3-10% in the future. The future increased rainfall has significant effect on the frequency of flood in future as well. This study analyzed the probability of future flood to investigate the stability of existing and new installed hydraulic structures and the possibility of increasing flood damage in mid-sized watersheds in South Korea. To achieve this goal, we first clarified the relationship between flood quantiles acquired from the flood-frequency analysis (FFA) and design rainfall-runoff analysis (DRRA) in gauged watersheds. Then, after synthetically generating the regional natural flow data according to RCP climate change scenarios, we developed mathematical formulas to estimate future flood quantiles based on the regression between DRRA and FFA incorporated with regional natural flows in unguaged watersheds. Finally, we developed a flood risk map to investigate the change of flood risk in terms of the return period for the past, present, and future. The results identified that the future flood quantiles and risks would increase in accordance with the RCP climate change scenarios. Because the regional flood risk was identified to increase in future comparing with the present status, comprehensive flood control will be needed to cope with extreme floods in future.

Internationally coordinated multi-mission planning is now critical to sustain the space-based rainfall observations needed for managing floods globally

NASA Astrophysics Data System (ADS)

Reed, Patrick M.; Chaney, Nathaniel W.; Herman, Jonathan D.; Ferringer, Matthew P.; Wood, Eric F.

2015-02-01

At present 4 of 10 dedicated rainfall observing satellite systems have exceeded their design life, some by more than a decade. Here, we show operational implications for flood management of a ‘collapse’ of space-based rainfall observing infrastructure as well as the high-value opportunities for a globally coordinated portfolio of satellite missions and data services. Results show that the current portfolio of rainfall missions fails to meet operational data needs for flood management, even when assuming a perfectly coordinated data product from all current rainfall-focused missions (i.e., the full portfolio). In the full portfolio, satellite-based rainfall data deficits vary across the globe and may preclude climate adaptation in locations vulnerable to increasing flood risks. Moreover, removing satellites that are currently beyond their design life (i.e., the reduced portfolio) dramatically increases data deficits globally and could cause entire high intensity flood events to be unobserved. Recovery from the reduced portfolio is possible with internationally coordinated replenishment of as few as 2 of the 4 satellite systems beyond their design life, yielding rainfall data coverages that outperform the current full portfolio (i.e., an optimized portfolio of eight satellites can outperform ten satellites). This work demonstrates the potential for internationally coordinated satellite replenishment and data services to substantially enhance the cost-effectiveness, sustainability and operational value of space-based rainfall observations in managing evolving flood risks.

A finite-element model study of the impact of the proposed I-326 crossing on flood stages of the Congaree River near Columbia, South Carolina

USGS Publications Warehouse

Lee, J.K.; Bennett, C. S.

1981-01-01

A two-dimensional finite element surface water model was used to study the hydraulic impact of the proposed Interstate Route 326 crossing of the Congaree River near Columbia, SC. The finite element model was assessed as a potential operational tool for analyzing complex highway crossings and other modifications of river flood plains. Infrared aerial photography was used to define regions of homogeneous roughness in the flood plain. Finite element networks approximating flood plain topography were designed using elements of three roughness types. High water marks established during an 8-yr flood that occurred in October 1976 were used to calibrate the model. The maximum flood of record, an approximately 100-yr flood that occurred in August 1908, was modeled in three cases: dikes on the right bank, dikes on the left bank, and dikes on both banks. In each of the three cases, simulations were performed both without and with the proposed highway embankments in place. Detailed information was obtained about backwater effects upstream from the proposed highway embankments, changes in flow distribution resulting from the embankments, and local velocities in the bridge openings. On the basis of results from the model study, the South Carolina Department of Highways and Public Transportation changed the design of several bridge openings. A simulation incorporating the new design for the case with dikes on the left bank indicated that both velocities in the bridge openings and backwater were reduced. A major problem in applying the model was the difficulty in predicting the network detail necessary to avoid local errors caused by roughness discontinuities and large depth gradients. (Lantz-PTT)

Understanding the effects of past flood events and perceived and estimated flood risks on individuals' voluntary flood insurance purchase behavior.

PubMed

Shao, Wanyun; Xian, Siyuan; Lin, Ning; Kunreuther, Howard; Jackson, Nida; Goidel, Kirby

2017-01-01

Over the past several decades, the economic damage from flooding in the coastal areas has greatly increased due to rapid coastal development coupled with possible climate change impacts. One effective way to mitigate excessive economic losses from flooding is to purchase flood insurance. Only a minority of coastal residents however have taken this preventive measure. Using original survey data for all coastal counties of the United States Gulf Coast merged with contextual data, this study examines the effects of external influences and perceptions of flood-related risks on individuals' voluntary behaviors to purchase flood insurance. It is found that the estimated flood hazard conveyed through the U.S. Federal Emergency Management Agency's (FEMA's) flood maps, the intensities and consequences of past storms and flooding events, and perceived flood-related risks significantly affect individual's voluntary purchase of flood insurance. This behavior is also influenced by home ownership, trust in local government, education, and income. These findings have several important policy implications. First, FEMA's flood maps have been effective in conveying local flood risks to coastal residents, and correspondingly influencing their decisions to voluntarily seek flood insurance in the U.S. Gulf Coast. Flood maps therefore should be updated frequently to reflect timely and accurate information about flood hazards. Second, policy makers should design strategies to increase homeowners' trust in the local government, to better communicate flood risks with residents, to address the affordability issue for the low-income, and better inform less educated homeowners through various educational programs. Future studies should examine the voluntary flood insurance behavior across countries that are vulnerable to flooding. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sequential planning of flood protection infrastructure under limited historic flood record and climate change uncertainty

NASA Astrophysics Data System (ADS)

Dittes, Beatrice; Špačková, Olga; Straub, Daniel

2017-04-01

Flood protection is often designed to safeguard people and property following regulations and standards, which specify a target design flood protection level, such as the 100-year flood level prescribed in Germany (DWA, 2011). In practice, the magnitude of such an event is only known within a range of uncertainty, which is caused by limited historic records and uncertain climate change impacts, among other factors (Hall & Solomatine, 2008). As more observations and improved climate projections become available in the future, the design flood estimate changes and the capacity of the flood protection may be deemed insufficient at a future point in time. This problem can be mitigated by the implementation of flexible flood protection systems (that can easily be adjusted in the future) and/or by adding an additional reserve to the flood protection, i.e. by applying a safety factor to the design. But how high should such a safety factor be? And how much should the decision maker be willing to pay to make the system flexible, i.e. what is the Value of Flexibility (Špačková & Straub, 2017)? We propose a decision model that identifies cost-optimal decisions on flood protection capacity in the face of uncertainty (Dittes et al. 2017). It considers sequential adjustments of the protection system during its lifetime, taking into account its flexibility. The proposed framework is based on pre-posterior Bayesian decision analysis, using Decision Trees and Markov Decision Processes, and is fully quantitative. It can include a wide range of uncertainty components such as uncertainty associated with limited historic record or uncertain climate or socio-economic change. It is shown that since flexible systems are less costly to adjust when flood estimates are changing, they justify initially lower safety factors. Investigation on the Value of Flexibility (VoF) demonstrates that VoF depends on the type and degree of uncertainty, on the learning effect (i.e. kind and quality of information that we will gather in the future) and on the formulation of the optimization problem (risk-based vs. rule-based approach). The application of the framework is demonstrated on catchments in Germany. References: DWA (Deutsche Vereinigung für Wasserwirtschaft Abwasser und Abfall eV.) 2011. Merkblatt DWA-M 507-1: Deiche an Fließgewässern. (A. Bieberstein, Ed.). Hennef: DWA Deutsche Vereinigung für Wasserwirtschaft, Abwasser und Abfall e. V. Hall, J., & Solomatine, D. 2008. A framework for uncertainty analysis in flood risk management decisions. International Journal of River Basin Management, 6(2), 85-98. http://doi.org/10.1080/15715124.2008.9635339 Špačková, O. & Straub, D. 2017. Long-term adaption decisions via fully and partially observable Markov decision processes. Sustainable and Resilient Infrastructure. In print.

Evaluation of the flood hydrology in the Colorado Front Range using precipitation, streamflow, and paleoflood data for the Big Thompson River basin

USGS Publications Warehouse

Jarrett, R.D.; Costa, J.E.

1988-01-01

A multidisciplinary study of precipitation and streamflow data and paleohydrologic studies of channel features was made to analyze the flood hydrology of foothill and mountain streams in the Front Range of Colorado, with emphasis on the Big Thompson River basin, because conventional hydrologic analyses do not adequately characterize the flood hydrology. In the foothills of Colorado, annual floodflows are derived from snowmelt at high elevations in the mountain regions, from rainfall at low elevation in the plains or plateau regions, or from a combination of rain falling on snow or mixed population hydrology. Above approximately 7,500 ft, snowmelt dominates; rain does not contribute to the flood potential. Regional flood-frequency relations were developed and compared with conventional flood-estimating technique results, including an evaluation of the magnitude and frequency of the probable maximum flood. Evaluation of streamflow data and paleoflood investigations provide an alternative for evaluating flood hydrology and the safety of dams. The study indicates the need for additional data collection and research to understand the complexities of the flood hydrology in mountainous regions, especially its effects on flood-plain management and the design of structures in the flood plain. (USGS)

Importance of record length with respect to estimating the 1-percent chance flood

USGS Publications Warehouse

Feaster, Toby D.

2010-01-01

U.S. Geological Survey (USGS) streamflow gages have been established in every State in the Nation, Puerto Rico, and the Trust Territory of the Pacific Islands. From these st reamflow records, estimates of the magnitude and frequency of floods are often developed and used to design transportation and water- conveyance structures to protect lives and property, and to determine flood-insurance rates. Probably the most recognizable flood statistic computed from USGS stream gaging records is the 1- percent (%) chance flood; better known has the 100-year flood. By definition, this is a flood that has a 1% chance of occurring in any given year. The 1% chance flood is a statistical estimate that can be significantly influenced by length of record and extreme flood events captured in that record. Consequently, it is typically recommended that flood statistics be updated on some regular interval such as every 10 years. This paper examines the influence of record length on the 1% chance flood for the Broad River in Georgia and the substantial difference that can occur in the estimate based on record length and the hydrologic conditions under which that record was collected. 

Recent changes in flood damage in the United States from observations and ACME model

NASA Astrophysics Data System (ADS)

Leng, G.; Leung, L. R.

2017-12-01

Despite efforts to mitigate flood hazards in flood-prone areas, survey- and report-based flood databases show that flood damage has increased and emerged as one of the most costly disaster in the United States since the 1990s. Understanding the mechanism driving the changes in flood damage is therefore critical for reducing flood risk. In this study, we first conduct a comprehensive analysis of the changing characteristics of flood damage at local, state and country level. Results show a significant increasing trend in the number of flood hazards, causing economic losses of up to $7 billion per year. The ratio of flood events that caused tangible economical cost to the total flood events has exhibited a non-significant increasing trend before 2007 followed by a significant decrease, indicating a changing vulnerability to floods. Analysis also reveals distinct spatial and temporal patterns in the threshold intensity of flood hazards with tangible economical cost. To understand the mechanism behind the increasing flood damage, we develop a flood damage economic model coupled with the integrated hydrological modeling system of ACME that features a river routing model with an inundation parameterization and a water use and regulation model. The model is evaluated over the country against historical records. Several numerical experiments are then designed to explore the mechanisms behind the recent changes in flood damage from the perspective of flood hazard, exposure and vulnerability, which constitute flood damage. The role of human activities such as reservoir operations and water use in modifying regional floods are also explored using the new tool, with the goal of improving understanding and modeling of vulnerability to flood hazards.

Costs and benefits of adapting to river floods at the global scale

NASA Astrophysics Data System (ADS)

Ward, Philip; Aerts, Jeroen; Botzen, Wouter; Hallegatte, Stephane; Jongman, Brenden; Kind, Jarl; Scussolini, Paolo; Winsemius, Hessel

2015-04-01

It is well known that the economic losses associated with flooding are huge; for example in 2012 alone the economic losses from flooding exceeded 19 billion. As a result, different models have been developed to assess global scale flood risk. Recently, these have been used in several studies to assess current flood risk at the global scale, and to project how risk may increase as a result of climate change and/or socioeconomic development. In most regions, these studies show rapid increases in risk into the future, and therefore call for urgent adaptation. However, to date no studies have attempted to assess the costs of carrying out such adaptation, nor the benefits. In this paper, we therefore present the first global scale estimate of the costs and benefits of adapting to increased river flood risk caused by factors such as climate change and socioeconomic development. For this study, we concentrate on structural adaptation measures, such as dikes, designed to prevent flood hazard up to a certain design standard. We address two questions: 1. What would be the costs and benefits of maintaining current flood protection standards, accounting for future climate and socioeconomic change until 2100? 2. What flood protection standards would be required by 2100 to keep future flood risk constant at today's levels? And what would be the costs and benefits associated with this? In this paper, we will present our first global estimates of the costs and benefits of adaptation to increased flood risk, as well as maps of these findings per country and river basin. We present the results under 4 emission scenarios (RCPs), 5 socioeconomic scenarios (SSPs), and under several assumptions relating to total potential flood damages, discount rates, construction costs, maintenance costs, and so forth. The research was carried out using the GLOFRIS modelling cascade. This global flood risk model calculates flood risk in terms of annual expected damage, and has been developed and validated over the past few years. For this study we have extended GLOFRIS by developing a module that calculates the costs and benefits of adaptation by increasing dike flood protection standards. In brief, this is carried out by calculating, per cell, the length of dikes that would be required to provide flood protection, multiplying this with the change in dike height that would be required to offer a certain flood protection standard, and multiplying this with data on the costs of dike construction and maintenance.

The Wildcat-San Pablo Creek Flood Control Project and Its Implications for the Design of Environmentally Sensitive Flood Management Plans

Treesearch

A. L. Riley

1989-01-01

In 1982 a coalition of neighborhood and environmental organizations used a community organizing strategy of the early 1960's, referred to as "advocacy planning" to substantially redesign a traditional structural type of joint federal and local flood control project on Wildcat and San Pablo Creeks in North Richmond, California. Using a combination of...

Thermosyphon Flooding in Reduced Gravity Environments

NASA Technical Reports Server (NTRS)

Gibson, Marc Andrew

2013-01-01

An innovative experiment to study the thermosyphon flooding limits was designed and flown on aparabolic flight campaign to achieve the Reduced Gravity Environments (RGE) needed to obtainempirical data for analysis. Current correlation models of Faghri and Tien and Chung do not agreewith the data. A new model is presented that predicts the flooding limits for thermosyphons inearths gravity and lunar gravity with a 95 confidence level of +- 5W.

The Effects of Saltwater Intrusion to Flood Mitigation Project

NASA Astrophysics Data System (ADS)

Azida Abu Bakar, Azinoor; Khairudin Khalil, Muhammad

2018-03-01

The objective of this study is to determine the effects of saltwater intrusion to flood mitigation project located in the flood plains in the district of Muar, Johor. Based on the studies and designs carried out, one of the effective flood mitigation options identified is the Kampung Tanjung Olak bypass and Kampung Belemang bypass at the lower reaches of Sungai Muar. But, the construction of the Kampung Belemang and Tanjung Olak bypass, while speeding up flood discharges, may also increase saltwater intrusion during drought low flows. Establishing the dynamics of flooding, including replicating the existing situation and the performance with prospective flood mitigation interventions, is most effectively accomplished using computer-based modelling tools. The finding of this study shows that to overcome the problem, a barrage should be constructed at Sungai Muar to solve the saltwater intrusion and low yield problem of the river.

Factors related to the joint probability of flooding on paired streams

USGS Publications Warehouse

Koltun, G.F.; Sherwood, J.M.

1998-01-01

The factors related to the joint probabilty of flooding on paired streams were investigated and quantified to provide information to aid in the design of hydraulic structures where the joint probabilty of flooding is an element of the design criteria. Stream pairs were considered to have flooded jointly at the design-year flood threshold (corresponding to the 2-, 10-, 25-, or 50-year instantaneous peak streamflow) if peak streamflows at both streams in the pair were observed or predicted to have equaled or exceeded the threshold on a given calendar day. Daily mean streamflow data were used as a substitute for instantaneous peak streamflow data to determine which flood thresholds were equaled or exceeded on any given day. Instantaneous peak streamflow data, when available, were used preferentially to assess flood-threshold exceedance. Daily mean streamflow data for each stream were paired with concurrent daily mean streamflow data at the other streams. Observed probabilities of joint flooding, determined for the 2-, 10-, 25-, and 50-year flood thresholds, were computed as the ratios of the total number of days when streamflows at both streams concurrently equaled or exceeded their flood thresholds (events) to the total number of days where streamflows at either stream equaled or exceeded its flood threshold (trials). A combination of correlation analyses, graphical analyses, and logistic-regression analyses were used to identify and quantify factors associated with the observed probabilities of joint flooding (event-trial ratios). The analyses indicated that the distance between drainage area centroids, the ratio of the smaller to larger drainage area, the mean drainage area, and the centroid angle adjusted 30 degrees were the basin characteristics most closely associated with the joint probabilty of flooding on paired streams in Ohio. In general, the analyses indicated that the joint probabilty of flooding decreases with an increase in centroid distance and increases with increases in drainage area ratio, mean drainage area, and centroid angle adjusted 30 degrees. Logistic-regression equations were developed, which can be used to estimate the probability that streamflows at two streams jointly equal or exceed the 2-year flood threshold given that the streamflow at one of the two streams equals or exceeds the 2-year flood threshold. The logistic-regression equations are applicable to stream pairs in Ohio (and border areas of adjacent states) that are unregulated, free of significant urban influences, and have characteristics similar to those of the 304 gaged stream pairs used in the logistic-regression analyses. Contingency tables were constructed and analyzed to provide information about the bivariate distribution of floods on paired streams. The contingency tables showed that the percentage of trials in which both streams in the pair concurrently flood at identical recurrence-interval ranges generally increased as centroid distances decreased and was greatest for stream pairs with adjusted centroid angles greater than or equal to 60 degrees and drainage area ratios greater than or equal to 0.01. Also, as centroid distance increased, streamflow at one stream in the pair was more likely to be in a less than 2-year recurrence-interval range when streamflow at the second stream was in a 2-year or greater recurrence-interval range.

A restatement of the natural science evidence concerning catchment-based ‘natural’ flood management in the UK

PubMed Central

Hall, Jim W.; Murgatroyd, Anna; Acreman, Mike; Bates, Paul; Beven, Keith; Heathwaite, Louise; Holden, Joseph; Holman, Ian P.; Lane, Stuart N.; O'Connell, Enda; Penning-Rowsell, Edmund; Reynard, Nick; Sear, David; Thorne, Colin; Wilby, Rob

2017-01-01

Flooding is a very costly natural hazard in the UK and is expected to increase further under future climate change scenarios. Flood defences are commonly deployed to protect communities and property from flooding, but in recent years flood management policy has looked towards solutions that seek to mitigate flood risk at flood-prone sites through targeted interventions throughout the catchment, sometimes using techniques which involve working with natural processes. This paper describes a project to provide a succinct summary of the natural science evidence base concerning the effectiveness of catchment-based ‘natural’ flood management in the UK. The evidence summary is designed to be read by an informed but not technically specialist audience. Each evidence statement is placed into one of four categories describing the nature of the underlying information. The evidence summary forms the appendix to this paper and an annotated bibliography is provided in the electronic supplementary material. PMID:28413336

Flood of July 21, 1975 in Mercer County, New Jersey

USGS Publications Warehouse

Stankowski, Stephen J.; Schopp, Robert D.; Velnich, Anthony J.

1975-01-01

Intense rainfall during the evening of July 20 and early morning hours of July 21, 1975 caused flooding of unprecedented magnitude in highly urbanized Mercer County, New Jersey. Over 6 inches (152 millimetres) of rainfall was recorded during a 10-hour period at Trenton, the capital of New Jersey. No lives were lost but damages to highways and bridges, to industrial, business, and residential buildings, to farmlands and crops, and to water supply systems were severe. This report illustrates the magnitude of the flood and provides hydrologic data needed for planning and design to control or lessen damages from future floods. It includes discussions of the antecedent conditions and meteorological aspects of the storm; a description of the flood and comparison to previous floods; a summary of flood stages and discharges; a discussion of flood frequency; and photomosaics which show inundated areas. More than 200 high-water marks are described as to location and elevation above mean sea level.

The Development of Microbial Fuel Cells (MFCs) By Haplusterts Soil (Samo - Thod Series)

NASA Astrophysics Data System (ADS)

Intaravicha, N.; Changjan, A.

2018-05-01

In this paper, we investigated on simultaneous electric energy production and organic matter was removed from synthetic wastewater by Microbial Fuel Cells (MFCs). Single chamber MFCs was made up by Haplusterts great group soil (Samo - Thod soil group) in trial design 3 x 3 factorial design in Completely Randomize Design (CRD) which 3 levels synthetic wastewater; 0, 200 and 400 mg/l of glucose and 3 levels of flooding time: 1, 3 and 5 days. The results showed the interaction significant with decreasing sugar from synthesis wastewater and Open Circuit Voltage (OCV). The maximum OCV of 200 and 400 mg/l of glucose in 3 flooding days were 131 and 142 mV and decreasing to 110 and 126 mV in 5 flooding days, respectively. The highest percent of decreased glucose approached to 80% in 5 flooding days of 0.4 g/l of glucose. The findings suggested that not only MFCs were a significantly to reduce organic matter in wastewater but also generated electric energy in the same time.

Flood risk assessment in France: comparison of extreme flood estimation methods (EXTRAFLO project, Task 7)

NASA Astrophysics Data System (ADS)

Garavaglia, F.; Paquet, E.; Lang, M.; Renard, B.; Arnaud, P.; Aubert, Y.; Carre, J.

2013-12-01

In flood risk assessment the methods can be divided in two families: deterministic methods and probabilistic methods. In the French hydrologic community the probabilistic methods are historically preferred to the deterministic ones. Presently a French research project named EXTRAFLO (RiskNat Program of the French National Research Agency, https://extraflo.cemagref.fr) deals with the design values for extreme rainfall and floods. The object of this project is to carry out a comparison of the main methods used in France for estimating extreme values of rainfall and floods, to obtain a better grasp of their respective fields of application. In this framework we present the results of Task 7 of EXTRAFLO project. Focusing on French watersheds, we compare the main extreme flood estimation methods used in French background: (i) standard flood frequency analysis (Gumbel and GEV distribution), (ii) regional flood frequency analysis (regional Gumbel and GEV distribution), (iii) local and regional flood frequency analysis improved by historical information (Naulet et al., 2005), (iv) simplify probabilistic method based on rainfall information (i.e. Gradex method (CFGB, 1994), Agregee method (Margoum, 1992) and Speed method (Cayla, 1995)), (v) flood frequency analysis by continuous simulation approach and based on rainfall information (i.e. Schadex method (Paquet et al., 2013, Garavaglia et al., 2010), Shyreg method (Lavabre et al., 2003)) and (vi) multifractal approach. The main result of this comparative study is that probabilistic methods based on additional information (i.e. regional, historical and rainfall information) provide better estimations than the standard flood frequency analysis. Another interesting result is that, the differences between the various extreme flood quantile estimations of compared methods increase with return period, staying relatively moderate up to 100-years return levels. Results and discussions are here illustrated throughout with the example of five watersheds located in the South of France. References : O. CAYLA : Probability calculation of design floods abd inflows - SPEED. Waterpower 1995, San Francisco, California 1995 CFGB : Design flood determination by the gradex method. Bulletin du Comité Français des Grands Barrages News 96, 18th congress CIGB-ICOLD n2, nov:108, 1994. F. GARAVAGLIA et al. : Introducing a rainfall compound distribution model based on weather patterns subsampling. Hydrology and Earth System Sciences, 14, 951-964, 2010. J. LAVABRE et al. : SHYREG : une méthode pour l'estimation régionale des débits de crue. application aux régions méditerranéennes françaises. Ingénierie EAT, 97-111, 2003. M. MARGOUM : Estimation des crues rares et extrêmes : le modèle AGREGEE. Conceptions et remières validations. PhD, Ecole des Mines de Paris, 1992. R. NAULET et al. : Flood frequency analysis on the Ardèche river using French documentary sources from the two last centuries. Journal of Hydrology, 313:58-78, 2005. E. PAQUET et al. : The SCHADEX method: A semi-continuous rainfall-runoff simulation for extreme flood estimation, Journal of Hydrology, 495, 23-37, 2013.

Estimating design flood and HEC-RAS modelling approach for flood analysis in Bojonegoro city

NASA Astrophysics Data System (ADS)

Prastica, R. M. S.; Maitri, C.; Hermawan, A.; Nugroho, P. C.; Sutjiningsih, D.; Anggraheni, E.

2018-03-01

Bojonegoro faces flood every year with less advanced prevention development. Bojonegoro city development could not peak because the flood results material losses. It affects every sectors in Bojonegoro: education, politics, economy, social, and infrastructure development. This research aims to analyse and to ensure that river capacity has high probability to be the main factor of flood in Bojonegoro. Flood discharge analysis uses Nakayasu synthetic unit hydrograph for period of 5 years, 10 years, 25 years, 50 years, and 100 years. They would be compared to the water maximum capacity that could be loaded by downstream part of Bengawan Solo River in Bojonegoro. According to analysis result, Bengawan Solo River in Bojonegoro could not able to load flood discharges. Another method used is HEC-RAS analysis. The conclusion that shown by HEC-RAS analysis has the same view. It could be observed that flood water loading is more than full bank capacity elevation in the river. To conclude, the main factor that should be noticed by government to solve flood problem is river capacity.

Recurrent floods and prevalence of diarrhea among under five children: observations from Bahraich district, Uttar Pradesh, India

PubMed Central

Joshi, Pooran C.; Kaushal, Sonia; Aribam, Bijaya S.; Khattri, Prashant; D'Aoust, Olivia; Singh, Mongjam M.; Marx, Michael; Guha-Sapir, Debarati

2011-01-01

Background Diarrhea is an important problem among the under-five children in India. Objective The paper examines long-term impacts of recurrent floods on diarrhea among under-five children in Uttar Pradesh, India. Design A two stage stratified cluster survey was conducted in flood affected (exposed) and non-flood affected areas (unexposed). Results The long-term impact of the floods was not clearly marked in the overall prevalence of diarrhea with the exposed group having prevalence of 55.1% as against 56.2% in the unexposed group of children under five. Economic condition of the household is associated with the prevalence of diarrhea in both exposed and unexposed strata. Anemia was found to be a significant risk factor for diarrhea among children in both the flood exposed and non-flood exposed populations. The recurrent floods did not have any significant effect on the prevalence of diarrhea in relation to gender, religion, caste, and household size. Conclusions The study indicates that the long-term impacts of floods are very differently manifested than the immediate impacts. PMID:21695069

Ancient flood records from historical documents in Korea

NASA Astrophysics Data System (ADS)

Kim, H. J.; Noh, S. J.; Jang, C. H.

2009-04-01

This paper is designed to comprehensively study a myriad of floods that have been witnessed on the Korean Peninsula for the past two millennia, by reviewing historical documents. The floods between the era of Three Kingdoms and the age of the Choson Dynasty were listed in the Chronicles of Three Kingdoms on the Korean Peninsula, the History of the Goreyo Dynasty, and the Annals of the Choson Dynasty and the Encyclopedic Annals of the Korean History & Culture (Dongguk Munheon Bigo). In particular, the Annals of the Choson Dynasty provided an ample store of flood records. Based on the data, Korea is judged to have continuously experienced nationwide floods in the 17th century.

Hospital infection prevention and control issues relevant to extensive floods.

PubMed

Apisarnthanarak, Anucha; Mundy, Linda M; Khawcharoenporn, Thana; Glen Mayhall, C

2013-02-01

The devastating clinical and economic implications of floods exemplify the need for effective global infection prevention and control (IPC) strategies for natural disasters. Reopening of hospitals after excessive flooding requires a balance between meeting the medical needs of the surrounding communities and restoration of a safe hospital environment. Postflood hospital preparedness plans are a key issue for infection control epidemiologists, healthcare providers, patients, and hospital administrators. We provide recent IPC experiences related to reopening of a hospital after extensive black-water floods necessitated hospital closures in Thailand and the United States. These experiences provide a foundation for the future design, execution, and analysis of black-water flood preparedness plans by IPC stakeholders.

Large-scale testing of in-vessel debris cooling through external flooding of the reactor pressure vessel in the CYBL facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chu, T.Y.; Bentz, J.H.; Bergeron, K.D.

1994-04-01

The possibility of achieving in-vessel core retention by flooding the reactor cavity, or the ``flooded cavity``, is an accident management concept currently under consideration for advanced light water reactors (ALWR), as well as for existing light water reactors (LWR). The CYBL (CYlindrical BoiLing) facility is a facility specifically designed to perform large-scale confirmatory testing of the flooded cavity concept. CYBL has a tank-within-a-tank design; the inner 3.7 m diameter tank simulates the reactor vessel, and the outer tank simulates the reactor cavity. The energy deposition on the bottom head is simulated with an array of radiant heaters. The array canmore » deliver a tailored heat flux distribution corresponding to that resulting from core melt convection. The present paper provides a detailed description of the capabilities of the facility, as well as results of recent experiments with heat flux in the range of interest to those required for in-vessel retention in typical ALWRs. The paper concludes with a discussion of other experiments for the flooded cavity applications.« less

A new modelling framework and mitigation measures for increased resilience to flooding

NASA Astrophysics Data System (ADS)

Valyrakis, Manousos; Alexakis, Athanasios; Solley, Mark

2015-04-01

Flooding in rivers and estuaries is amongst the most significant challenges our society has yet to tackle effectively. Use of floodwall systems is one of the potential measures that can be used to mitigate the detrimental socio-economical and ecological impacts and alleviate the associated costs of flooding. This work demonstrates the utility of such systems for a case study via appropriate numerical simulations, in addition to conducting scaled flume experiments towards obtaining a better understanding of the performance and efficiency of the flood-wall systems. At first, the results of several characteristic inundation modeling scenarios and flood mitigation options, for a flood-prone region in Scotland. In particular, the history and hydrology of the area are discussed and the assumptions and hydraulic model input (model geometry including instream hydraulic structures -such as bridges and weirs- river and floodplain roughness, initial and boundary conditions) are presented, followed by the model results. Emphasis is given on the potential improvements brought about by mitigating flood risk using flood-wall systems. Further, the implementation of the floodwall in mitigating flood risk is demonstrated via appropriate numerical modeling, utilizing HEC-RAS to simulate the effect of a river's rising stage during a flood event, for a specific area. The later part of this work involves the design, building and utilization of a scaled physical model of a flood-wall system. These experiments are carried out at one of the research flumes in the Water Engineering laboratory of the University of Glasgow. These involve an experimental investigation where the increase of force applied on the floodwall is measured for different degrees of deflection of the water in the stream, under the maximum flow discharge that can be carried through without exceeding the floodwall height (and accounting for the effect of super-elevation). These results can be considered upon the implementation phase of floodwalls, when the floodwalls are placed at any arrangement other than parallel to the flow (e.g. along river bends in meandering channels or at river junctions). Such considerations can lead to site-specific optimal designs of direct flood defenses with the rising floodwall system, both in terms of product performance as well as cost efficiency.

Dependency of high coastal water level and river discharge at the global scale

NASA Astrophysics Data System (ADS)

Ward, P.; Couasnon, A.; Haigh, I. D.; Muis, S.; Veldkamp, T.; Winsemius, H.; Wahl, T.

2017-12-01

It is widely recognized that floods cause huge socioeconomic impacts. From 1980-2013, global flood losses exceeded $1 trillion, with 220,000 fatalities. These impacts are particularly hard felt in low-lying densely populated deltas and estuaries, whose location at the coast-land interface makes them naturally prone to flooding. When river and coastal floods coincide, their impacts in these deltas and estuaries are often worse than when they occur in isolation. Such floods are examples of so-called `compound events'. In this contribution, we present the first global scale analysis of the statistical dependency of high coastal water levels (and the storm surge component alone) and river discharge. We show that there is statistical dependency between these components at more than half of the stations examined. We also show time-lags in the highest correlation between peak discharges and coastal water levels. Finally, we assess the probability of the simultaneous occurrence of design discharge and design coastal water levels, assuming both independence and statistical dependence. For those stations where we identified statistical dependency, the probability is between 1 and 5 times greater, when the dependence structure is accounted for. This information is essential for understanding the likelihood of compound flood events occurring at locations around the world as well as for accurate flood risk assessments and effective flood risk management. The research was carried out by analysing the statistical dependency between observed coastal water levels (and the storm surge component) from GESLA-2 and river discharge using gauged data from GRDC stations all around the world. The dependence structure was examined using copula functions.

Probabilistic modelling of flood events using the entropy copula

NASA Astrophysics Data System (ADS)

Li, Fan; Zheng, Qian

2016-11-01

The estimation of flood frequency is vital for the flood control strategies and hydraulic structure design. Generating synthetic flood events according to statistical properties of observations is one of plausible methods to analyze the flood frequency. Due to the statistical dependence among the flood event variables (i.e. the flood peak, volume and duration), a multidimensional joint probability estimation is required. Recently, the copula method is widely used for multivariable dependent structure construction, however, the copula family should be chosen before application and the choice process is sometimes rather subjective. The entropy copula, a new copula family, employed in this research proposed a way to avoid the relatively subjective process by combining the theories of copula and entropy. The analysis shows the effectiveness of the entropy copula for probabilistic modelling the flood events of two hydrological gauges, and a comparison of accuracy with the popular copulas was made. The Gibbs sampling technique was applied for trivariate flood events simulation in order to mitigate the calculation difficulties of extending to three dimension directly. The simulation results indicate that the entropy copula is a simple and effective copula family for trivariate flood simulation.

Area Handbook Series: Bangladesh, A Country Study

DTIC Science & Technology

1988-09-01

tions, and overutilization of critical resources, were seen as having exacerbated the 1988 flooding. Heavy runoff through the flat, over- populated...recovering from the 1987 floods. Although flood cotrol was seen by some observers as the responsibility of Bangladesh, regional cooperation in water...The manufacture of electronic com- ponents, started only in 1985 and designed for export to Singa- pore, Hong Kong, and the United States, was seen in

A fast method for optical simulation of flood maps of light-sharing detector modules

PubMed Central

Shi, Han; Du, Dong; Xu, JianFeng; Moses, William W.; Peng, Qiyu

2016-01-01

Optical simulation of the detector module level is highly desired for Position Emission Tomography (PET) system design. Commonly used simulation toolkits such as GATE are not efficient in the optical simulation of detector modules with complicated light-sharing configurations, where a vast amount of photons need to be tracked. We present a fast approach based on a simplified specular reflectance model and a structured light-tracking algorithm to speed up the photon tracking in detector modules constructed with polished finish and specular reflector materials. We simulated conventional block detector designs with different slotted light guide patterns using the new approach and compared the outcomes with those from GATE simulations. While the two approaches generated comparable flood maps, the new approach was more than 200–600 times faster. The new approach has also been validated by constructing a prototype detector and comparing the simulated flood map with the experimental flood map. The experimental flood map has nearly uniformly distributed spots similar to those in the simulated flood map. In conclusion, the new approach provides a fast and reliable simulation tool for assisting in the development of light-sharing-based detector modules with a polished surface finish and using specular reflector materials. PMID:27660376

A fast method for optical simulation of flood maps of light-sharing detector modules

DOE PAGES

Shi, Han; Du, Dong; Xu, JianFeng; ...

2015-09-03

Optical simulation of the detector module level is highly desired for Position Emission Tomography (PET) system design. Commonly used simulation toolkits such as GATE are not efficient in the optical simulation of detector modules with complicated light-sharing configurations, where a vast amount of photons need to be tracked. Here, we present a fast approach based on a simplified specular reflectance model and a structured light-tracking algorithm to speed up the photon tracking in detector modules constructed with polished finish and specular reflector materials. We also simulated conventional block detector designs with different slotted light guide patterns using the new approachmore » and compared the outcomes with those from GATE simulations. And while the two approaches generated comparable flood maps, the new approach was more than 200–600 times faster. The new approach has also been validated by constructing a prototype detector and comparing the simulated flood map with the experimental flood map. The experimental flood map has nearly uniformly distributed spots similar to those in the simulated flood map. In conclusion, the new approach provides a fast and reliable simulation tool for assisting in the development of light-sharing-based detector modules with a polished surface finish and using specular reflector materials.« less

Flood design recipes vs. reality: can predictions for ungauged basins be trusted?

NASA Astrophysics Data System (ADS)

Efstratiadis, A.; Koussis, A. D.; Koutsoyiannis, D.; Mamassis, N.

2013-12-01

Despite the great scientific and technological advances in flood hydrology, everyday engineering practices still follow simplistic approaches, such as the rational formula and the SCS-CN method combined with the unit hydrograph theory that are easy to formally implement in ungauged areas. In general, these "recipes" have been developed many decades ago, based on field data from few experimental catchments. However, many of them have been neither updated nor validated across all hydroclimatic and geomorphological conditions. This has an obvious impact on the quality and reliability of hydrological studies, and, consequently, on the safety and cost of the related flood protection works. Preliminary results, based on historical flood data from Cyprus and Greece, indicate that a substantial revision of many aspects of flood engineering procedures is required, including the regionalization formulas as well as the modelling concepts themselves. In order to provide a consistent design framework and to ensure realistic predictions of the flood risk (a key issue of the 2007/60/EU Directive) in ungauged basins, it is necessary to rethink the current engineering practices. In this vein, the collection of reliable hydrological data would be essential for re-evaluating the existing "recipes", taking into account local peculiarities, and for updating the modelling methodologies as needed.

Storm Duration and Antecedent Moisture Conditions for Flood Discharge Estimation

DOT National Transportation Integrated Search

2003-11-01

Design flows estimated by flood hydrograph simulation can be reasonably accurate or greatly in error, depending upon the modeling procedures and inputs selected. The objectives of this research project were (1) to determine which combinations of mode...

Flood boundaries and water-surface profile for the computed 100-year flood, Swift Creek at Afton, Wyoming, 1986

USGS Publications Warehouse

Rankl, James G.; Wallace, Joe C.

1989-01-01

Flood flows on Swift Creek near Afton, Wyoming, were analyzed. Peak discharge with an average recurrence interval of 100 years was computed and used to determine the flood boundaries and water surface profile in the study reach. The study was done in cooperation with Lincoln County and the Town of Afton to determine the extent of flooding in the Town of Afton from a 100-year flood on Swift Creek. The reach of Swift Creek considered in the analysis extends upstream from the culvert at Allred County Road No. 12-135 to the US Geological Survey streamflow-gaging station located in the Bridger National Forest , a distance of 3.2 miles. Boundaries of the 100-year flood are delineated on a map using the computed elevation of the flood at each cross section, survey data, and a 1983 aerial photograph. The computed water surface elevation for the 100-year flood was plotted at each cross section, then the lateral extent of the flood was transferred to the flood map. Boundaries between cross sections were sketched using information taken from the aerial photograph. Areas that are inundated, but not part of the active flow, are designated on the cross sections. (Lantz-PTT)

Incidence of and risk factors for musculoskeletal symptoms in the neck and low-back during severe flooding in Bangkok in 2011.

PubMed

Sihawong, Rattaporn; Janwantanakul, Prawit; Pensri, Praneet

2012-07-01

To examine whether the incidences of neck and low-back symptoms were elevated during the severe floods that occurred in Bangkok, Thailand in 2011, and to explore flood-related risk factors for neck and low-back symptoms. Prospective cohort design. Severe flooding occurred in Bangkok and surrounding neighbourhoods between October and December, 2011. After the flood had subsided (January 2012), 377 healthy office workers, who were already taking part in a study on musculoskeletal symptoms, were asked about their contact with floodwater. Data were gathered from subjects, who had reported no neck and low-back symptoms at the end of September 2011 and who were affected by the flood. Two regression models for the outcomes of 3-month incidence of neck and low-back symptoms, respectively, were performed. Eighty-two percent of the subjects were affected by the flood. No flood-related factor was found to associate significantly with either neck or low-back symptoms. However, neck symptoms may be associated with commuting frequently through flooded areas, and low-back symptoms may be associated with the subjects' homes or workplaces being flooded. These findings indicate that more attention needs to be paid to the problem of musculoskeletal symptoms during flooding in urban areas, and that preventive measures are required.

Holistic flood risk assessment using agent-based modelling: the case of Sint Maarten Island

NASA Astrophysics Data System (ADS)

Abayneh Abebe, Yared; Vojinovic, Zoran; Nikolic, Igor; Hammond, Michael; Sanchez, Arlex; Pelling, Mark

2015-04-01

Floods in coastal regions are regarded as one of the most dangerous and harmful disasters. Though commonly referred to as natural disasters, coastal floods are also attributable to various social, economic, historical and political issues. Rapid urbanisation in coastal areas combined with climate change and poor governance can lead to a significant increase in the risk of pluvial flooding coinciding with fluvial and coastal flooding posing a greater risk of devastation in coastal communities. Disasters that can be triggered by hydro-meteorological events are interconnected and interrelated with both human activities and natural processes. They, therefore, require holistic approaches to help understand their complexity in order to design and develop adaptive risk management approaches that minimise social and economic losses and environmental impacts, and increase resilience to such events. Being located in the North Atlantic Ocean, Sint Maarten is frequently subjected to hurricanes. In addition, the stormwater catchments and streams on Sint Maarten have several unique characteristics that contribute to the severity of flood-related impacts. Urban environments are usually situated in low-lying areas, with little consideration for stormwater drainage, and as such are subject to flash flooding. Hence, Sint Maarten authorities drafted policies to minimise the risk of flood-related disasters on the island. In this study, an agent-based model is designed and applied to understand the implications of introduced policies and regulations, and to understand how different actors' behaviours influence the formation, propagation and accumulation of flood risk. The agent-based model built for this study is based on the MAIA meta-model, which helps to decompose, structure and conceptualize socio-technical systems with an agent-oriented perspective, and is developed using the NetLogo simulation environment. The agents described in this model are households and businesses, and policies on spatial planning rules are implemented. Preliminary results demonstrate the evolving nature of flood risks and describe the effectiveness of different planning policies to reduce risk and increase resilience.

Generation of synthetic flood hydrographs by hydrological donors (SHYDONHY method)

NASA Astrophysics Data System (ADS)

Paquet, Emmanuel

2017-04-01

For the design of hydraulic infrastructures like dams, a design hydrograph is required in most of the cases. Some of its features (e.g. peak value, duration, volume) corresponding to a given return period are computed thanks to a wide range of methods: historical records, mono or multivariate statistical analysis, stochastic simulation, etc. Then various methods have been proposed to construct design hydrographs having such characteristics, ranging from traditional unit-hydrograph to statistical methods (Yue et al., 2002). A new method to build design hydrographs (or more generally synthetic hydrographs) is introduced here, named SHYDONHY, French acronym for "Synthèse d'HYdrogrammes par DONneurs HYdrologiques". It is based on an extensive database of 100 000 flood hydrographs recorded at hourly time-step on 1300 gauging stations in France and Switzerland, covering a wide range of catchment size and climatology. For each station, an average of two hydrographs per year of record has been selected by a peak-over-threshold (POT) method with independence criteria (Lang et al., 1999). This sampling ensures that only hydrographs of intense floods are gathered in the dataset. For a given catchment, where few or no hydrograph is available at the outlet, a sub-set of 10 "donor stations" is selected within the complete dataset, considering several criteria: proximity, size, mean annual values and regimes for both total runoff and POT-selected floods. This sub-set of stations (and their corresponding flood hydrographs) will allow to: • Estimate a characteristic duration of flood hydrographs (e.g. duration for which the discharge is above 50% of the peak value). • For a given duration (e.g. one day), estimate the average peak-to- volume ratio of floods. • For a given duration and peak-to-volume ratio, generation of a synthetic reference hydrograph by combining appropriate hydrographs of the sub-set. • For a given daily discharge sequence, being observed or generated for extreme flood estimation, generate a suitable synthetic hydrograph, also by combining selected hydrographs of the sub-set. The reliability of the method is assessed by performing a jackknife validation on the whole dataset of stations, in particular by reconstructing the hydrograph of the biggest flood of each station and comparing it to the actual one. Some applications are presented, e.g. the coupling of SHYDONHY with the SCHADEX method (Paquet et al., 2003) for the stochastic simulation of extreme reservoir level in dams. References: Lang, M., Ouarda, T. B. M. J., & Bobée, B. (1999). Towards operational guidelines for over-threshold modeling. Journal of hydrology, 225(3), 103-117. Paquet, E., Garavaglia, F., Garçon, R., & Gailhard, J. (2013). The SCHADEX method: A semi-continuous rainfall-runoff simulation for extreme flood estimation. Journal of Hydrology, 495, 23-37. Yue, S., Ouarda, T. B., Bobée, B., Legendre, P., & Bruneau, P. (2002). Approach for describing statistical properties of flood hydrograph. Journal of hydrologic engineering, 7(2), 147-153.

Estimating design-flood discharges for streams in Iowa using drainage-basin and channel-geometry characteristics

USGS Publications Warehouse

Eash, D.A.

1993-01-01

Procedures provided for applying the drainage-basin and channel-geometry regression equations depend on whether the design-flood discharge estimate is for a site on an ungaged stream, an ungaged site on a gaged stream, or a gaged site. When both a drainage-basin and a channel-geometry regression-equation estimate are available for a stream site, a procedure is presented for determining a weighted average of the two flood estimates. The drainage-basin regression equations are applicable to unregulated rural drainage areas less than 1,060 square miles, and the channel-geometry regression equations are applicable to unregulated rural streams in Iowa with stabilized channels.

Process-based model with flood control measures towards more realistic global flood modeling

NASA Astrophysics Data System (ADS)

Tang, Q.; Zhang, X.; Wang, Y.; Mu, M.; Lv, A.; Li, Z.

2017-12-01

In the profoundly human-influenced era, the Anthropocene, increased amount of land was developed in flood plains and many flood control measures were implemented to protect people and infrastructures placed in the flood-prone areas. These human influences (for example, dams and dykes) have altered peak streamflow and flood risk, and are already an integral part of flood. However, most of the process-based flood models have yet to taken into account the human influences. In this study, we used a hydrological model together with an advanced hydrodynamic model to assess flood risk at the Baiyangdian catchment. The Baiyangdian Lake is the largest shallow freshwater lake in North China, and it was used as a flood storage area in the past. A new development hub for the Beijing-Tianjin-Hebei economic triangle, namely the Xiongan new area, was recently established in the flood-prone area around the lake. The shuttle radar topography mission (SRTM) digital elevation model (DEMs) was used to parameterize the hydrodynamic model simulation, and the inundation estimates were compared with published flood maps and observed inundation area during the extreme historical flood events. A simple scheme was carried out to consider the impacts of flood control measures, including the reservoirs in the headwaters and the dykes to be built. By comparing model simulations with and without the influences of flood control measures, we demonstrated the importance of human influences in altering the inundated area and depth under design flood conditions. Based on the SRTM DEM and dam and reservoir data in the Global Reservoir and Dam (GRanD) database, we further discuss the potential to develop a global flood model with human influences.

Effects of a flooding event on a threatened black bear population in Louisiana

USGS Publications Warehouse

O'Connell-Goode, Kaitlin C.; Lowe, Carrie L.; Clark, Joseph D.

2014-01-01

The Louisiana black bear, Ursus americanus luteolus, is listed as threatened under the Endangered Species Act as a result of habitat loss and human-related mortality. Information on population-level responses of large mammals to flooding events is scarce, and we had a unique opportunity to evaluate the viability of the Upper Atchafalaya River Basin (UARB) black bear population before and after a significant flooding event. We began collecting black bear hair samples in 2007 for a DNA mark-recapture study to estimate abundance (N) and apparent survival (φ). In 2011, the Morganza Spillway was opened to divert floodwaters from the Mississippi River through the UARB, inundating > 50% of our study area, potentially impacting recovery of this important bear population. To evaluate the effects of this flooding event on bear population dynamics, we used a robust design multistate model to estimate changes in transition rates from the flooded area to non-flooded area (ψF→NF) before (2007–2010), during (2010–2011) and after (2011–2012) the flood. Average N across all years of study was 63.2 (SE = 5.2), excluding the year of the flooding event. Estimates of ψF→NF increased from 0.014 (SE = 0.010; meaning that 1.4% of the bears moved from the flooded area to non-flooded areas) before flooding to 0.113 (SE = 0.045) during the flood year, and then decreased to 0.028 (SE= 0.035) after the flood. Although we demonstrated a flood effect on transition rates as hypothesized, the effect was small (88.7% of the bears remained in the flooded area during flooding) and φ was unchanged, suggesting that the 2011 flooding event had minimal impact on survival and site fidelity.

Long-term strategies of climate change adaptation to manage flooding events in urban areas

NASA Astrophysics Data System (ADS)

Pouget, Laurent; Russo, Beniamino; Redaño, Angel; Ribalaygua, Jaime

2010-05-01

Heavy and sudden rainfalls regularly affect the Mediterranean area, so a great number of people and buildings are exposed to the risk of rain-generated floods. Climate change is expected to modify this risk and, in the case that extreme rainfalls increase in frequencies and intensity, this could result in important damages, particularly in urban areas. This paper presents a project that aims to determine adaptation strategies to future flood risks in urban areas. It has been developed by a panel of water companies (R+i Alliance funding), and includes the evaluation of the climate change impact on the extreme rainfall, the use of innovative modelling tools to accurately forecast the flood risk and, finally, the definition of a pro-active and long-term planning against floods. This methodology has been applied in the city of Barcelona. Current climate models give some projections that are not directly applicable for flood risk studies, either because they do not have an adequate spatial and temporal resolution, or because they do not consider some important local factors, such as orography. These points have been considered within the project, when developing the design storms corresponding to future climatic conditions (e.g. years 2030 or 2050). The methodology uses statistical downscaling techniques based on global climate models predictions, including corrections for extreme events and convective storms, as well as temporal downscaling based on historical observations. The design storms created are used in combination with the predictions of sea level rise and land use evolutions to determine the future risk of flooding in the area of study. Once the boundary conditions are known, an accurate flood hazard assessment is done. It requires a local knowledge of the flow parameters in the whole analyzed domain. In urban catchments, in order to fulfill this requirement, powerful hydrological and hydraulic tools and detailed topographic data represent the unique way for a local estimation of the flow parameters (flow depth, flow velocity, flood duration, etc.). If urban floods are caused by heavy rainfall events and a quick hydrological response of the catchment, the approach to elaborate a flood hazard assessment study should take into account the drainage system capacity, too (in terms of effectiveness of surface drainage structures, as well as storm sewerages). In these cases, the hydrological modelling of the involved subcatchments should be linked to the runoff propagation 2D modelling on the urban surface and the hydraulics of the storm sewers (dual drainage modelling) through a coupled 2D/1D approach. The design storm created and the 2D/1D modelling approach have been used to simulate the future flood risk in the city of Barcelona. From the simulation results, it is possible to understand the flooding processes and the risk associated. It is therefore possible to develop some long-term adaptation strategies to reduce the flood risk for current and future climatic conditions, such as structural measures (e.g. improvement of the stormwater network) and non-structural measures (e.g. enhancement of the flood warning system).

Combining Empirical and Stochastic Models for Extreme Floods Estimation

NASA Astrophysics Data System (ADS)

Zemzami, M.; Benaabidate, L.

2013-12-01

Hydrological models can be defined as physical, mathematical or empirical. The latter class uses mathematical equations independent of the physical processes involved in the hydrological system. The linear regression and Gradex (Gradient of Extreme values) are classic examples of empirical models. However, conventional empirical models are still used as a tool for hydrological analysis by probabilistic approaches. In many regions in the world, watersheds are not gauged. This is true even in developed countries where the gauging network has continued to decline as a result of the lack of human and financial resources. Indeed, the obvious lack of data in these watersheds makes it impossible to apply some basic empirical models for daily forecast. So we had to find a combination of rainfall-runoff models in which it would be possible to create our own data and use them to estimate the flow. The estimated design floods would be a good choice to illustrate the difficulties facing the hydrologist for the construction of a standard empirical model in basins where hydrological information is rare. The construction of the climate-hydrological model, which is based on frequency analysis, was established to estimate the design flood in the Anseghmir catchments, Morocco. The choice of using this complex model returns to its ability to be applied in watersheds where hydrological information is not sufficient. It was found that this method is a powerful tool for estimating the design flood of the watershed and also other hydrological elements (runoff, volumes of water...).The hydrographic characteristics and climatic parameters were used to estimate the runoff, water volumes and design flood for different return periods.

Crest-stage gaging stations in Oregon: a compilation of peak data collected from October 1952 to September 1974

USGS Publications Warehouse

Friday, John

1974-01-01

A crest-stage gaging station provides an excellent means for determining peak water-surface elevations at a selected location on a stream channel. When related to streamflow, these data provide hydrologists with a knowledge of the flood experience of a drainage basin. If an adequate flood history is known, it is possible to estimate the probable magnitude and frequency of floods likely to occur in that basin, and this information is a valuable asset to anyone who must estimate design floods at proposed drainage structures. However, most design problems involve estimating peak flows on ungaged streams. This is difficult because the rate of storm runoff is not the same in all basins due to the influence of various basin characteristics which can either assist or retard the runoff. The crest-stage gaging program in Oregon is designed to provide a representative sampliing of peak flows at basins having a wide range in characteristics. Then, after sufficient data are collected, a statistical analysis can be made which will provide a means for estimating design floods at ungaged sites on the basis of known basin characteristics.This report is one of a series presenting a compilation of peak data collected at 232 crest-stage gaging stations in Oregon. The collection and publication of these data are made possible through mutual funding by State and Federal agencies. The Geological Survey, the Oregon State Highway Commission, the Federal Highway Administration, and the Bureau of Land Management are currently supporting 160 active crest-stage stations in Oregon.

Improving Flash Flood Prediction in Multiple Environments

NASA Astrophysics Data System (ADS)

Broxton, P. D.; Troch, P. A.; Schaffner, M.; Unkrich, C.; Goodrich, D.; Wagener, T.; Yatheendradas, S.

2009-12-01

Flash flooding is a major concern in many fast responding headwater catchments . There are many efforts to model and to predict these flood events, though it is not currently possible to adequately predict the nature of flash flood events with a single model, and furthermore, many of these efforts do not even consider snow, which can, by itself, or in combination with rainfall events, cause destructive floods. The current research is aimed at broadening the applicability of flash flood modeling. Specifically, we will take a state of the art flash flood model that is designed to work with warm season precipitation in arid environments, the KINematic runoff and EROSion model (KINEROS2), and combine it with a continuous subsurface flow model and an energy balance snow model. This should improve its predictive capacity in humid environments where lateral subsurface flow significantly contributes to streamflow, and it will make possible the prediction of flooding events that involve rain-on-snow or rapid snowmelt. By modeling changes in the hydrologic state of a catchment before a flood begins, we can also better understand the factors or combination of factors that are necessary to produce large floods. Broadening the applicability of an already state of the art flash flood model, such as KINEROS2, is logical because flash floods can occur in all types of environments, and it may lead to better predictions, which are necessary to preserve life and property.

The Impact of Corps Flood Control Reservoirs in the June 2008 Upper Mississippi Flood

NASA Astrophysics Data System (ADS)

Charley, W. J.; Stiman, J. A.

2008-12-01

The US Army Corps of Engineers is responsible for a multitude of flood control project on the Mississippi River and its tributaries, including levees that protect land from flooding, and dams to help regulate river flows. The first six months of 2008 were the wettest on record in the upper Mississippi Basin. During the first 2 weeks of June, rainfall over the Midwest ranged from 6 to as much as 16 inches, overwhelming the flood protection system, causing massive flooding and damage. Most severely impacted were the States of Iowa, Illinois, Indiana, Missouri, and Wisconsin. In Iowa, flooding occurred on almost every river in the state. On the Iowa River, record flooding occurred from Marshalltown, Iowa, downstream to its confluence with the Mississippi River. At several locations, flooding exceeded the 500-year event. The flooding affected agriculture, transportation, and infrastructure, including homes, businesses, levees, and other water-control structures. It has been estimated that there was at least 7 billion dollars in damages. While the flooding in Iowa was extraordinary, Corps of Engineers flood control reservoirs helped limit damage and prevent loss of life, even though some reservoirs were filled beyond their design capacity. Coralville Reservoir on the Iowa River, for example, filled to 135% of its design flood storage capacity, with stage a record five feet over the crest of the spillway. In spite of this, the maximum reservoir release was limited to 39,500 cfs, while a peak inflow of 57,000 cfs was observed. CWMS, the Corps Water Management System, is used to help regulate Corps reservoirs, as well as track and evaluate flooding and flooding potential. CWMS is a comprehensive data acquisition and hydrologic modeling system for short-term decision support of water control operations in real time. It encompasses data collection, validation and transformation, data storage, visualization, real time model simulation for decision-making support, and data dissemination. The system uses precipitation and flow data, collected in real-time, along with forecasted flow from the National Weather Service to model and optimize reservoir operations and forecast downstream flows and stages, providing communities accurate and timely information to aid their flood-fighting. This involves integrating several simulation modeling programs, including HEC-HMS to forecast flows, HEC-ResSim to model reservoir operations and HEC-RAS to compute forecasted stage hydrographs. An inundation boundary and depth map of water in the flood plain can be calculated from the HEC-RAS results using ArcInfo. By varying future precipitation and releases, engineers can evaluate different "What if?" scenarios. The effectiveness of this tool and Corps reservoirs are examined.

75 FR 67382 - Agency Information Collection Activities: Submission for OMB Review; Comment Request, OMB No...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-02

...-89D), Coastal Structures Form; FEMA Form 086-0-27E (formerly FEMA Form 81-89E), Alluvial Fan Flooding... Fan Flooding Form. Abstract: The certification forms are designed to assist requesters in gathering...

44 CFR 201.2 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... SECURITY DISASTER ASSISTANCE MITIGATION PLANNING § 201.2 Definitions. Administrator means the head of the Federal Emergency Management Agency, or his/her designated representative. Flood Mitigation Assistance (FMA) means the program authorized by section 1366 of the National Flood Insurance Act of 1968, as...

44 CFR 201.2 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... SECURITY DISASTER ASSISTANCE MITIGATION PLANNING § 201.2 Definitions. Administrator means the head of the Federal Emergency Management Agency, or his/her designated representative. Flood Mitigation Assistance (FMA) means the program authorized by section 1366 of the National Flood Insurance Act of 1968, as...

44 CFR 201.2 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... SECURITY DISASTER ASSISTANCE MITIGATION PLANNING § 201.2 Definitions. Administrator means the head of the Federal Emergency Management Agency, or his/her designated representative. Flood Mitigation Assistance (FMA) means the program authorized by section 1366 of the National Flood Insurance Act of 1968, as...

44 CFR 201.2 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... SECURITY DISASTER ASSISTANCE MITIGATION PLANNING § 201.2 Definitions. Administrator means the head of the Federal Emergency Management Agency, or his/her designated representative. Flood Mitigation Assistance (FMA) means the program authorized by section 1366 of the National Flood Insurance Act of 1968, as...

44 CFR 201.2 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... SECURITY DISASTER ASSISTANCE MITIGATION PLANNING § 201.2 Definitions. Administrator means the head of the Federal Emergency Management Agency, or his/her designated representative. Flood Mitigation Assistance (FMA) means the program authorized by section 1366 of the National Flood Insurance Act of 1968, as...

Innovations in Stream Restoration and Flood Control Design Meeting Flood Capacity and Environmental Goals on San Luis Obispo Creek

Treesearch

Wayne Peterson

1989-01-01

Can a natural flowing creek be increased in drainage capacity to protect an adjacent community from flooding while still maintaining a natural habitat? San Luis Obispo constructed one such project on over a mile of Creek as a part of a housing development. The City found that some of the mitigation measures included in the project worked while others did not. In the...

Community Based Flood Modeling in Southern and Baja California to Meet End User Needs for Decision-Making

NASA Astrophysics Data System (ADS)

Sanders, B. F.

2017-12-01

Flooding of coastal and fluvial systems are the most significant natural hazards facing society, and damages have been escalating for decades globally and in the U.S. Almost all metropolitan areas are exposed to flood risk. The threat from river flooding is especially high in India and China, and coastal cities around the world are threatened by storm surge and rising sea levels. Several trends including rising sea levels, urbanization, deforestation, and rural-to-urban population shifts will increase flood exposure in the future. Flood impacts are escalating despite advances in hazards science and extensive effort to manage risks. The fundamental issue is not that flooding is becoming more severe, even though it is in some places, but rather that societies are become more vulnerable to flood impacts. A critical factor contributing to the escalation of flood impacts is that the most vulnerable sectors of communities are left out of processes to prepare for and respond to flooding. Furthermore, the translation of knowledge about flood hazards and vulnerabilities into actionable information for communities has not been effective. In Southern and Baja California, an interdisciplinary team of researchers has partnered with stakeholders in flood vulnerable communities to co-develop flood hazard information systems designed to meet end-user needs for decision-making. The initiative leveraged the power of advanced, fine-scale hydraulic models of flooding to craft intuitive visualizations of context-sensitive scenarios. This presentation will cover the ways by which the process of flood inundation modeling served as a focal point for knowledge development, as well as the unique visualizations that populate on-line information systems accessible here: http://floodrise.uci.edu/online-flood-hazard-viewers/

Mapping Daily and Maximum Flood Extents at 90-m Resolution During Hurricanes Harvey and Irma Using Passive Microwave Remote Sensing

NASA Astrophysics Data System (ADS)

Galantowicz, J. F.; Picton, J.; Root, B.

2017-12-01

Passive microwave remote sensing can provided a distinct perspective on flood events by virtue of wide sensor fields of view, frequent observations from multiple satellites, and sensitivity through clouds and vegetation. During Hurricanes Harvey and Irma, we used AMSR2 (Advanced Microwave Scanning Radiometer 2, JAXA) data to map flood extents starting from the first post-storm rain-free sensor passes. Our standard flood mapping algorithm (FloodScan) derives flooded fraction from 22-km microwave data (AMSR2 or NASA's GMI) in near real time and downscales it to 90-m resolution using a database built from topography, hydrology, and Global Surface Water Explorer data and normalized to microwave data footprint shapes. During Harvey and Irma we tested experimental versions of the algorithm designed to map the maximum post-storm flood extent rapidly and made a variety of map products available immediately for use in storm monitoring and response. The maps have several unique features including spanning the entire storm-affected area and providing multiple post-storm updates as flood water shifted and receded. From the daily maps we derived secondary products such as flood duration, maximum flood extent (Figure 1), and flood depth. In this presentation, we describe flood extent evolution, maximum extent, and local details as detected by the FloodScan algorithm in the wake of Harvey and Irma. We compare FloodScan results to other available flood mapping resources, note observed shortcomings, and describe improvements made in response. We also discuss how best-estimate maps could be updated in near real time by merging FloodScan products and data from other remote sensing systems and hydrological models.

Evaluation of levee setbacks for flood-loss reduction, Middle Mississippi River, USA

NASA Astrophysics Data System (ADS)

Dierauer, Jennifer; Pinter, Nicholas; Remo, Jonathan W. F.

2012-07-01

SummaryOne-dimensional hydraulic modeling and flood-loss modeling were used to test the effectiveness of levee setbacks for flood-loss reduction along the Middle Mississippi River (MMR). Four levee scenarios were assessed: (1) the present-day levee configuration, (2) a 1000 m levee setback, (3) a 1500 m levee setback, and (4) an optimized setback configuration. Flood losses were estimated using FEMA's Hazus-MH (Hazards US Multi-Hazard) loss-estimation software on a structure-by-structure basis for a range of floods from the 2- to the 500-year events. These flood-loss estimates were combined with a levee-reliability model to calculate probability-weighted damage estimates. In the simplest case, the levee setback scenarios tested here reduced flood losses compared to current conditions for large, infrequent flooding events but increased flood losses for smaller, more frequent flood events. These increases occurred because levee protection was removed for some of the existing structures. When combined with buyouts of unprotected structures, levee setbacks reduced flood losses for all recurrence intervals. The "optimized" levee setback scenario, involving a levee configuration manually planned to protect existing high-value infrastructure, reduced damages with or without buyouts. This research shows that levee setbacks in combination with buyouts are an economically viable approach for flood-risk reduction along the study reach and likely elsewhere where levees are widely employed for flood control. Designing a levee setback around existing high-value infrastructure can maximize the benefit of the setback while simultaneously minimizing the costs. The optimized levee setback scenario analyzed here produced payback periods (costs divided by benefits) of less than 12 years. With many aging levees failing current inspections across the US, and flood losses spiraling up over time, levee setbacks are a viable solution for reducing flood exposure and flood levels.

Bridge scour and change in contracted section, Razor Creek

USGS Publications Warehouse

Holnbeck, Stephen R.; Parrett, Charles; Tillinger, Todd N.; ,

1993-01-01

Two large floods, 3 and 4 times the estimated 100-year peak discharge, occurred in 1986 and 1991 at a timber-pile bridge over Razor Creek in Montana. A bridge section surveyed after the 1991 flood was compared with a 1955 design section and showed total scour of 0.85 m at the left abutment, 2.23 m at the right abutment, and 0. 94 m at the pile bents. Calculated total scour based on equations recommended by the Federal Highway Administration and data obtained after the 1991 flood was 3.20 m at the left abutment, 4.36 m at the right abutment, and 2.13 m at the pile bents. Residual scour from floods prior to 1986 was presumed to be negligible because no floods of significant magnitude were documented. Also, scour for the 1986 flood is believed to be significantly less than for the 1991 flood because the 1986 peak discharge was significantly smaller and the contracted section for the 1986 peak discharge was 22 m upstream from the bridge.

Interaction of flooding and salinity stress on baldcypress (Taxodium distichum)

USGS Publications Warehouse

Allen, J.A.; Pezeshki, S.R.; Chambers, J.L.

1996-01-01

Coastal wetlands of the southeastern United States are threatened by increases in flooding and salinity as a result of both natural processes and man-induced hydrologic alterations. Furthermore, global climate change scenarios suggest that, as a consequence of rising sea levels, much larger areas of coastal wetlands may be affected by flooding and salinity in the next 50 to 100 years. In this paper, we review studies designed to improve our ability to predict and ameliorate the impacts of increased flooding and salinity stress on baldcypress (Taxodium distichum (L.) Rich.), which is a dominant species of many coastal forested wetlands. Specifically, we review studies on species-level responses to flooding and salinity stress, alone and in combination, we summarize two studies on intraspecific variation in response to flooding and salinity stress, we analyze the physiological mechanisms thought to be responsible for the interaction between flooding and salinity stress, and we discuss the implications for coastal wetland loss and the prospects for developing salt-tolerant lines of baldcypress.

Nuclear Power Plant Mechanical Component Flooding Fragility Experiments Status

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pope, C. L.; Savage, B.; Johnson, B.

This report describes progress on Nuclear Power Plant mechanical component flooding fragility experiments and supporting research. The progress includes execution of full scale fragility experiments using hollow-core doors, design of improvements to the Portal Evaluation Tank, equipment procurement and initial installation of PET improvements, designation of experiments exploiting the improved PET capabilities, fragility mathematical model development, Smoothed Particle Hydrodynamic simulations, wave impact simulation device research, and pipe rupture mechanics research.

Dynamics of flood water infiltration and ground water recharge in hyperarid desert.

PubMed

Dahan, Ofer; Tatarsky, Boaz; Enzel, Yehouda; Kulls, Christoph; Seely, Mary; Benito, Gererdo

2008-01-01

A study on flood water infiltration and ground water recharge of a shallow alluvial aquifer was conducted in the hyperarid section of the Kuiseb River, Namibia. The study site was selected to represent a typical desert ephemeral river. An instrumental setup allowed, for the first time, continuous monitoring of infiltration during a flood event through the channel bed and the entire vadose zone. The monitoring system included flexible time domain reflectometry probes that were designed to measure the temporal variation in vadose zone water content and instruments to concurrently measure the levels of flood and ground water. A sequence of five individual floods was monitored during the rainy season in early summer 2006. These newly generated data served to elucidate the dynamics of flood water infiltration. Each flood initiated an infiltration event which was expressed in wetting of the vadose zone followed by a measurable rise in the water table. The data enabled a direct calculation of the infiltration fluxes by various independent methods. The floods varied in their stages, peaks, and initial water contents. However, all floods produced very similar flux rates, suggesting that the recharge rates are less affected by the flood stages but rather controlled by flow duration and available aquifer storage under it. Large floods flood the stream channel terraces and promote the larger transmission losses. These, however, make only a negligible contribution to the recharge of the ground water. It is the flood duration within the active streambed, which may increase with flood magnitude that is important to the recharge process.

Database assessment of CMIP5 and hydrological models to determine flood risk areas

NASA Astrophysics Data System (ADS)

Limlahapun, Ponthip; Fukui, Hiromichi

2016-11-01

Solutions for water-related disasters may not be solved with a single scientific method. Based on this premise, we involved logic conceptions, associate sequential result amongst models, and database applications attempting to analyse historical and future scenarios in the context of flooding. The three main models used in this study are (1) the fifth phase of the Coupled Model Intercomparison Project (CMIP5) to derive precipitation; (2) the Integrated Flood Analysis System (IFAS) to extract amount of discharge; and (3) the Hydrologic Engineering Center (HEC) model to generate inundated areas. This research notably focused on integrating data regardless of system-design complexity, and database approaches are significantly flexible, manageable, and well-supported for system data transfer, which makes them suitable for monitoring a flood. The outcome of flood map together with real-time stream data can help local communities identify areas at-risk of flooding in advance.

Strategically placing green infrastructure: cost-effective land conservation in the floodplain.

PubMed

Kousky, Carolyn; Olmstead, Sheila M; Walls, Margaret A; Macauley, Molly

2013-04-16

Green infrastructure approaches have attracted increased attention from local governments as a way to lower flood risk and provide an array of other environmental services. The peer-reviewed literature, however, offers few estimates of the economic impacts of such approaches at the watershed scale. We estimate the avoided flood damages and the costs of preventing development of floodplain parcels in the East River Watershed of Wisconsin's Lower Fox River Basin. Results suggest that the costs of preventing conversion of all projected floodplain development would exceed the flood damage mitigation benefits by a substantial margin. However, targeting of investments to high-benefit, low-cost parcels can reverse this equation, generating net benefits. The analysis demonstrates how any flood-prone community can use a geographic-information-based model to estimate the flood damage reduction benefits of green infrastructure, compare them to the costs, and target investments to design cost-effective nonstructural flood damage mitigation policies.

Coastal and river flood risk analyses for guiding economically optimal flood adaptation policies: a country-scale study for Mexico

NASA Astrophysics Data System (ADS)

Haer, Toon; Botzen, W. J. Wouter; van Roomen, Vincent; Connor, Harry; Zavala-Hidalgo, Jorge; Eilander, Dirk M.; Ward, Philip J.

2018-06-01

Many countries around the world face increasing impacts from flooding due to socio-economic development in flood-prone areas, which may be enhanced in intensity and frequency as a result of climate change. With increasing flood risk, it is becoming more important to be able to assess the costs and benefits of adaptation strategies. To guide the design of such strategies, policy makers need tools to prioritize where adaptation is needed and how much adaptation funds are required. In this country-scale study, we show how flood risk analyses can be used in cost-benefit analyses to prioritize investments in flood adaptation strategies in Mexico under future climate scenarios. Moreover, given the often limited availability of detailed local data for such analyses, we show how state-of-the-art global data and flood risk assessment models can be applied for a detailed assessment of optimal flood-protection strategies. Our results show that especially states along the Gulf of Mexico have considerable economic benefits from investments in adaptation that limit risks from both river and coastal floods, and that increased flood-protection standards are economically beneficial for many Mexican states. We discuss the sensitivity of our results to modelling uncertainties, the transferability of our modelling approach and policy implications. This article is part of the theme issue `Advances in risk assessment for climate change adaptation policy'.

Influence of risk factors and past events on flood resilience in coastal megacities: Comparative analysis of NYC and Shanghai.

PubMed

Xian, Siyuan; Yin, Jie; Lin, Ning; Oppenheimer, Michael

2018-01-01

Coastal flood protection measures have been widely implemented to improve flood resilience. However, protection levels vary among coastal megacities globally. This study compares the distinct flood protection standards for two coastal megacities, New York City and Shanghai, and investigates potential influences such as risk factors and past flood events. Extreme value analysis reveals that, compared to NYC, Shanghai faces a significantly higher flood hazard. Flood inundation analysis indicates that Shanghai has a higher exposure to extreme flooding. Meanwhile, Shanghai's urban development, population, and economy have increased much faster than NYC's over the last three decades. These risk factors provide part of the explanation for the implementation of a relatively high level of protection (e.g. reinforced concrete sea-wall designed for a 200-year flood return level) in Shanghai and low protection (e.g. vertical brick and stone walls and sand dunes) in NYC. However, individual extreme flood events (typhoons in 1962, 1974, and 1981) seem to have had a greater impact on flood protection decision-making in Shanghai, while NYC responded significantly less to past events (with the exception of Hurricane Sandy). Climate change, sea level rise, and ongoing coastal development are rapidly changing the hazard and risk calculus for both cities and both would benefit from a more systematic and dynamic approach to coastal protection. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluating the impact and risk of pluvial flash flood on intra-urban road network: A case study in the city center of Shanghai, China

NASA Astrophysics Data System (ADS)

Yin, Jie; Yu, Dapeng; Yin, Zhane; Liu, Min; He, Qing

2016-06-01

Urban pluvial flood are attracting growing public concern due to rising intense precipitation and increasing consequences. Accurate risk assessment is critical to an efficient urban pluvial flood management, particularly in transportation sector. This paper describes an integrated methodology, which initially makes use of high resolution 2D inundation modeling and flood depth-dependent measure to evaluate the potential impact and risk of pluvial flash flood on road network in the city center of Shanghai, China. Intensity-Duration-Frequency relationships of Shanghai rainstorm and Chicago Design Storm are combined to generate ensemble rainfall scenarios. A hydrodynamic model (FloodMap-HydroInundation2D) is used to simulate overland flow and flood inundation for each scenario. Furthermore, road impact and risk assessment are respectively conducted by a new proposed algorithm and proxy. Results suggest that the flood response is a function of spatio-temporal distribution of precipitation and local characteristics (i.e. drainage and topography), and pluvial flash flood is found to lead to proportionate but nonlinear impact on intra-urban road inundation risk. The approach tested here would provide more detailed flood information for smart management of urban street network and may be applied to other big cities where road flood risk is evolving in the context of climate change and urbanization.

Flood frequency estimation by national-scale continuous hydrological simulations: an application in Great Britain

NASA Astrophysics Data System (ADS)

Formetta, Giuseppe; Stewart, Elizabeth; Bell, Victoria; Reynard, Nick

2017-04-01

Estimation of peak discharge for an assigned return period is a crucial issue in engineering hydrology. It is required for designing and managing hydraulic infrastructure such as dams, reservoirs and bridges. In the UK, the Flood Estimation Handbook (FEH) recommends the use of the index flood method to estimate the design flood as the product of a local scale factor (the index flood, IF) and a dimensionless regional growth factor (GF). For gauged catchments the IF is usually estimated as the median annual maximum flood (QMED), while for ungauged catchments it is computed through multiple linear regression models based on a set of morpho-climatic indices of the basin. The GF is estimated by fitting the annual maxima with the generalised logistic distribution (GL) using two methods depending on the record length and the target return period: single-site or pooled analysis. The single site-analysis estimates the GF from the annual maxima of the subject site alone; the pooled analysis uses data from a set of catchments hydrologically similar to the subject site. In this work estimates of floods up to 100-year return period obtained from the FEH approach are compared to those obtained using Grid-to-Grid, a continuous physically-based hydrological model. The model converts rainfall and potential evapotranspiration into river flows by modelling surface/sub-surface runoff, lateral water movements, and snow-pack. It is configured on a 1km2 grid resolution and it uses spatial datasets of topography, soil, and land cover. It was set up in Great Britain and has been evaluated for the period 1960-2014 in forward-mode (i.e. without parameter calibration) using daily meteorological forcing data. The modelled floods with a given return period (5,10, 30, 50, and 100 years) were computed from the modelled discharge annual maxima and compared to the FEH estimates for 100 catchments in Great Britain. Preliminary results suggest that there is a good agreement between modelled and measured floods with a correlation coefficient that ranges from 0.8 for low return periods to 0.65 for the highest. It is shown that model performance is robust and independent of catchment features such as area and mean annual rainfall. The promising results for Great Britain support the aspiration that continuous simulation from large-scale hydrological models, supported by the increasing availability of global weather, climate and hydrological products, could be used to develop robust methods to help engineers estimate design floods in regions with limited gauge data or affected by environmental change.

Optimal adaptation to extreme rainfalls in current and future climate

NASA Astrophysics Data System (ADS)

Rosbjerg, Dan

2017-01-01

More intense and frequent rainfalls have increased the number of urban flooding events in recent years, prompting adaptation efforts. Economic optimization is considered an efficient tool to decide on the design level for adaptation. The costs associated with a flooding to the T-year level and the annual capital and operational costs of adapting to this level are described with log-linear relations. The total flooding costs are developed as the expected annual damage of flooding above the T-year level plus the annual capital and operational costs for ensuring no flooding below the T-year level. The value of the return period T that corresponds to the minimum of the sum of these costs will then be the optimal adaptation level. The change in climate, however, is expected to continue in the next century, which calls for expansion of the above model. The change can be expressed in terms of a climate factor (the ratio between the future and the current design level) which is assumed to increase in time. This implies increasing costs of flooding in the future for many places in the world. The optimal adaptation level is found for immediate as well as for delayed adaptation. In these cases, the optimum is determined by considering the net present value of the incurred costs during a sufficiently long time-span. Immediate as well as delayed adaptation is considered.

Optimal adaptation to extreme rainfalls under climate change

NASA Astrophysics Data System (ADS)

Rosbjerg, Dan

2017-04-01

More intense and frequent rainfalls have increased the number of urban flooding events in recent years, prompting adaptation efforts. Economic optimization is considered an efficient tool to decide on the design level for adaptation. The costs associated with a flooding to the T-year level and the annual capital and operational costs of adapting to this level are described with log-linear relations. The total flooding costs are developed as the expected annual damage of flooding above the T-year level plus the annual capital and operational costs for ensuring no flooding below the T-year level. The value of the return period T that corresponds to the minimum of the sum of these costs will then be the optimal adaptation level. The change in climate, however, is expected to continue in the next century, which calls for expansion of the above model. The change can be expressed in terms of a climate factor (the ratio between the future and the current design level) which is assumed to increase in time. This implies increasing costs of flooding in the future for many places in the world. The optimal adaptation level is found for immediate as well as for delayed adaptation. In these cases the optimum is determined by considering the net present value of the incurred costs during a sufficiently long time span. Immediate as well as delayed adaptation is considered.

Single well surfactant test to evaluate surfactant floods using multi tracer method

DOEpatents

Sheely, Clyde Q.

1979-01-01

Data useful for evaluating the effectiveness of or designing an enhanced recovery process said process involving mobilizing and moving hydrocarbons through a hydrocarbon bearing subterranean formation from an injection well to a production well by injecting a mobilizing fluid into the injection well, comprising (a) determining hydrocarbon saturation in a volume in the formation near a well bore penetrating formation, (b) injecting sufficient mobilizing fluid to mobilize and move hydrocarbons from a volume in the formation near the well bore, and (c) determining the hydrocarbon saturation in a volume including at least a part of the volume of (b) by an improved single well surfactant method comprising injecting 2 or more slugs of water containing the primary tracer separated by water slugs containing no primary tracer. Alternatively, the plurality of ester tracers can be injected in a single slug said tracers penetrating varying distances into the formation wherein the esters have different partition coefficients and essentially equal reaction times. The single well tracer method employed is disclosed in U.S. Pat. No. 3,623,842. This method designated the single well surfactant test (SWST) is useful for evaluating the effect of surfactant floods, polymer floods, carbon dioxide floods, micellar floods, caustic floods and the like in subterranean formations in much less time and at much reduced cost compared to conventional multiwell pilot tests.

Identification of Dominant Flood Drivers across Canada

NASA Astrophysics Data System (ADS)

Singh, J.; Karmakar, S.; Ghosh, S.; Simonovic, S.; Gusain, A.

2016-12-01

In recent past, flooding has taken a devastating form causing societal, economic, and environmental losses over the Globe. Reliable information on the cause of occurrence, time, and magnitude of flood events might be useful for effective planning, design and operation of hydraulic structures to minimize losses. In the present study, we used circular statistics to understand the pattern and seasonality in flooding across Canada. A set of analyses is performed on unregulated daily stream flow data from 318 stream gage stations (procure from HYDAT database) with a record of at least 40 years between 1951-2010. Further, an attempt is also made to identify possible primary drivers of flooding across Canada. To accomplish this, daily precipitation record from 561 stations and 10 resolution snowmelt data from ECMWF ERA 20C during 1951-2010 have been used. Majority of stations reported statistically significant negative trend in flood magnitude in south western part, whereas, an increasing trend in frequency of flooding observed in south eastern part of Canada. The results show a strong evidence of regional patterns of seasonality and inter-annual variability in flooding. It is observed, about 42% of flood events occur during spring (March-May) over south eastern part of Canada and are not associated with extreme precipitation, where snowmelt is found to be primary factor for occurrence of flood events. Further, about 44% of flood events occur during summer (June-August) in southwestern region and having strong association with extreme precipitation. Additionally, we observe the negative trend in precipitation driven flood events (summer flooding) in south western part of Canada. The present study on identification of major flood drivers across Canada shows a need to examine the influence of various climate indices quantifying variation of surface temperature anomalies, which will improve flood prediction and consequently flood risk management. Keywords: Canada, Flood drivers, Flood management, Precipitation, Snowmelt

A coupled hydrological-hydraulic flood inundation model calibrated using post-event measurements and integrated uncertainty analysis in a poorly gauged Mediterranean basin

NASA Astrophysics Data System (ADS)

Hdeib, Rouya; Abdallah, Chadi; Moussa, Roger; Colin, Francois

2017-04-01

Developing flood inundation maps of defined exceedance probabilities is required to provide information on the flood hazard and the associated risk. A methodology has been developed to model flood inundation in poorly gauged basins, where reliable information on the hydrological characteristics of floods are uncertain and partially captured by the traditional rain-gauge networks. Flood inundation is performed through coupling a hydrological rainfall-runoff (RR) model (HEC-HMS) with a hydraulic model (HEC-RAS). The RR model is calibrated against the January 2013 flood event in the Awali River basin, Lebanon (300 km2), whose flood peak discharge was estimated by post-event measurements. The resulting flows of the RR model are defined as boundary conditions of the hydraulic model, which is run to generate the corresponding water surface profiles and calibrated against 20 post-event surveyed cross sections after the January-2013 flood event. An uncertainty analysis is performed to assess the results of the models. Consequently, the coupled flood inundation model is simulated with design storms and flood inundation maps are generated of defined exceedance probabilities. The peak discharges estimated by the simulated RR model were in close agreement with the results from different empirical and statistical methods. This methodology can be extended to other poorly gauged basins facing common stage-gauge failure or characterized by floods with a stage exceeding the gauge measurement level, or higher than that defined by the rating curve.

33 CFR 203.15 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., after the structure has been damaged by a flood, hurricane, or coastal storm, to the level of protection... Washington, D.C. Hurricane/Shore Protection Project (HSPP). A flood control project designed and constructed... of hurricanes, tsunamis, and coastal storms. These effects are primarily to protect against wave...

Evaluation of design flood frequency methods for Iowa streams : final report, June 2009.

DOT National Transportation Integrated Search

2009-06-01

The objective of this project was to assess the predictive accuracy of flood frequency estimation for small Iowa streams based : on the Rational Method, the NRCS curve number approach, and the Iowa Runoff Chart. The evaluation was based on : comparis...

Status of the Flooding Fragility Testing Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pope, C. L.; Savage, B.; Bhandari, B.

2016-06-01

This report provides an update on research addressing nuclear power plant component reliability under flooding conditions. The research includes use of the Component Flooding Evaluation Laboratory (CFEL) where individual components and component subassemblies will be tested to failure under various flooding conditions. The resulting component reliability data can then be incorporated with risk simulation strategies to provide a more thorough representation of overall plant risk. The CFEL development strategy consists of four interleaved phases. Phase 1 addresses design and application of CFEL with water rise and water spray capabilities allowing testing of passive and active components including fully electrified components.more » Phase 2 addresses research into wave generation techniques followed by the design and addition of the wave generation capability to CFEL. Phase 3 addresses methodology development activities including small scale component testing, development of full scale component testing protocol, and simulation techniques including Smoothed Particle Hydrodynamic (SPH) based computer codes. Phase 4 involves full scale component testing including work on full scale component testing in a surrogate CFEL testing apparatus.« less

3D Simulation of External Flooding Events for the RISMC Pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prescott, Steven; Mandelli, Diego; Sampath, Ramprasad

2015-09-01

Incorporating 3D simulations as part of the Risk-Informed Safety Margins Characterization (RISMIC) Toolkit allows analysts to obtain a more complete picture of complex system behavior for events including external plant hazards. External events such as flooding have become more important recently – however these can be analyzed with existing and validated simulated physics toolkits. In this report, we describe these approaches specific to flooding-based analysis using an approach called Smoothed Particle Hydrodynamics. The theory, validation, and example applications of the 3D flooding simulation are described. Integrating these 3D simulation methods into computational risk analysis provides a spatial/visual aspect to themore » design, improves the realism of results, and can prove visual understanding to validate the analysis of flooding.« less

Impacts of representing sea-level rise uncertainty on future flood risks: An example from San Francisco Bay

PubMed Central

Oddo, Perry C.; Keller, Klaus

2017-01-01

Rising sea levels increase the probability of future coastal flooding. Many decision-makers use risk analyses to inform the design of sea-level rise (SLR) adaptation strategies. These analyses are often silent on potentially relevant uncertainties. For example, some previous risk analyses use the expected, best, or large quantile (i.e., 90%) estimate of future SLR. Here, we use a case study to quantify and illustrate how neglecting SLR uncertainties can bias risk projections. Specifically, we focus on the future 100-yr (1% annual exceedance probability) coastal flood height (storm surge including SLR) in the year 2100 in the San Francisco Bay area. We find that accounting for uncertainty in future SLR increases the return level (the height associated with a probability of occurrence) by half a meter from roughly 2.2 to 2.7 m, compared to using the mean sea-level projection. Accounting for this uncertainty also changes the shape of the relationship between the return period (the inverse probability that an event of interest will occur) and the return level. For instance, incorporating uncertainties shortens the return period associated with the 2.2 m return level from a 100-yr to roughly a 7-yr return period (∼15% probability). Additionally, accounting for this uncertainty doubles the area at risk of flooding (the area to be flooded under a certain height; e.g., the 100-yr flood height) in San Francisco. These results indicate that the method of accounting for future SLR can have considerable impacts on the design of flood risk management strategies. PMID:28350884

Impacts of representing sea-level rise uncertainty on future flood risks: An example from San Francisco Bay.

PubMed

Ruckert, Kelsey L; Oddo, Perry C; Keller, Klaus

2017-01-01

Rising sea levels increase the probability of future coastal flooding. Many decision-makers use risk analyses to inform the design of sea-level rise (SLR) adaptation strategies. These analyses are often silent on potentially relevant uncertainties. For example, some previous risk analyses use the expected, best, or large quantile (i.e., 90%) estimate of future SLR. Here, we use a case study to quantify and illustrate how neglecting SLR uncertainties can bias risk projections. Specifically, we focus on the future 100-yr (1% annual exceedance probability) coastal flood height (storm surge including SLR) in the year 2100 in the San Francisco Bay area. We find that accounting for uncertainty in future SLR increases the return level (the height associated with a probability of occurrence) by half a meter from roughly 2.2 to 2.7 m, compared to using the mean sea-level projection. Accounting for this uncertainty also changes the shape of the relationship between the return period (the inverse probability that an event of interest will occur) and the return level. For instance, incorporating uncertainties shortens the return period associated with the 2.2 m return level from a 100-yr to roughly a 7-yr return period (∼15% probability). Additionally, accounting for this uncertainty doubles the area at risk of flooding (the area to be flooded under a certain height; e.g., the 100-yr flood height) in San Francisco. These results indicate that the method of accounting for future SLR can have considerable impacts on the design of flood risk management strategies.

2010-2011 Queensland floods: using Haddon's Matrix to define and categorise public safety strategies.

PubMed

Zhong, Shuang; Clark, Michele; Hou, Xiang-Yu; Zang, Yu-Li; FitzGerald, Gerry

2013-08-01

The 2010-2011 Queensland floods resulted in the most deaths from a single flood event in Australia since 1916. This article analyses the information on these deaths for comparison with those from previous floods in modern Australia in an attempt to identify factors that have contributed to those deaths. Haddon's Matrix, originally designed for prevention of road trauma, offers a framework for understanding the interplay between contributing factors and helps facilitate a clearer understanding of the varied strategies required to ensure people's safety for particular flood types. Public reports and flood relevant literature were searched using key words 'flood', 'fatality', 'mortality', 'death', 'injury' and 'victim' through Google Scholar, PubMed, ProQuest and EBSCO. Data relating to reported deaths during the 2010-2011 Queensland floods, and relevant data of previous Australian flood fatality (1997-2009) were collected from these available sources. These sources were also used to identify contributing factors. There were 33 deaths directly attributed to the event, of which 54.5% were swept away in a flash flood on 10 January 2011. A further 15.1% of fatalities were caused by inappropriate behaviours. This is different to floods in modern Australia where over 90% of deaths are related to the choices made by individuals. There is no single reason why people drown in floods, but rather a complex interplay of factors. The present study and its integration of research findings and conceptual frameworks might assist governments and communities to develop policies and strategies to prevent flood injury and fatalities. © 2013 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

The index-flood and the GRADEX methods combination for flood frequency analysis.

NASA Astrophysics Data System (ADS)

Fuentes, Diana; Di Baldassarre, Giuliano; Quesada, Beatriz; Xu, Chong-Yu; Halldin, Sven; Beven, Keith

2017-04-01

Flood frequency analysis is used in many applications, including flood risk management, design of hydraulic structures, and urban planning. However, such analysis requires of long series of observed discharge data which are often not available in many basins around the world. In this study, we tested the usefulness of combining regional discharge and local precipitation data to estimate the event flood volume frequency curve for 63 catchments in Mexico, Central America and the Caribbean. This was achieved by combining two existing flood frequency analysis methods, the regionalization index-flood approach with the GRADEX method. For up to 10-years return period, similar shape of the scaled flood frequency curve for catchments with similar flood behaviour was assumed from the index-flood approach. For return periods larger than 10-years the probability distribution of rainfall and discharge volumes were assumed to be asymptotically and exponential-type functions with the same scale parameter from the GRADEX method. Results showed that if the mean annual flood (MAF), used as index-flood, is known, the index-flood approach performed well for up to 10 years return periods, resulting in 25% mean relative error in prediction. For larger return periods the prediction capability decreased but could be improved by the use of the GRADEX method. As the MAF is unknown at ungauged and short-period measured basins, we tested predicting the MAF using catchments climate-physical characteristics, and discharge statistics, the latter when observations were available for only 8 years. Only the use of discharge statistics resulted in acceptable predictions.

Assessing surface water flood risk and management strategies under future climate change: Insights from an Agent-Based Model.

PubMed

Jenkins, K; Surminski, S; Hall, J; Crick, F

2017-10-01

Climate change and increasing urbanization are projected to result in an increase in surface water flooding and consequential damages in the future. In this paper, we present insights from a novel Agent Based Model (ABM), applied to a London case study of surface water flood risk, designed to assess the interplay between different adaptation options; how risk reduction could be achieved by homeowners and government; and the role of flood insurance and the new flood insurance pool, Flood Re, in the context of climate change. The analysis highlights that while combined investment in property-level flood protection and sustainable urban drainage systems reduce surface water flood risk, the benefits can be outweighed by continued development in high risk areas and the effects of climate change. In our simulations, Flood Re is beneficial in its function to provide affordable insurance, even under climate change. However, the scheme does face increasing financial pressure due to rising surface water flood damages. If the intended transition to risk-based pricing is to take place then a determined and coordinated strategy will be needed to manage flood risk, which utilises insurance incentives, limits new development, and supports resilience measures. Our modelling approach and findings are highly relevant for the ongoing regulatory and political approval process for Flood Re as well as for wider discussions on the potential of insurance schemes to incentivise flood risk management and climate adaptation in the UK and internationally. Copyright © 2017 Elsevier B.V. All rights reserved.

AP1000{sup R} design robustness against extreme external events - Seismic, flooding, and aircraft crash

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pfister, A.; Goossen, C.; Coogler, K.

2012-07-01

Both the International Atomic Energy Agency (IAEA) and the U.S. Nuclear Regulatory Commission (NRC) require existing and new nuclear power plants to conduct plant assessments to demonstrate the unit's ability to withstand external hazards. The events that occurred at the Fukushima-Dai-ichi nuclear power station demonstrated the importance of designing a nuclear power plant with the ability to protect the plant against extreme external hazards. The innovative design of the AP1000{sup R} nuclear power plant provides unparalleled protection against catastrophic external events which can lead to extensive infrastructure damage and place the plant in an extended abnormal situation. The AP1000 plantmore » is an 1100-MWe pressurized water reactor with passive safety features and extensive plant simplifications that enhance construction, operation, maintenance and safety. The plant's compact safety related footprint and protection provided by its robust nuclear island structures prevent significant damage to systems, structures, and components required to safely shutdown the plant and maintain core and spent fuel pool cooling and containment integrity following extreme external events. The AP1000 nuclear power plant has been extensively analyzed and reviewed to demonstrate that it's nuclear island design and plant layout provide protection against both design basis and extreme beyond design basis external hazards such as extreme seismic events, external flooding that exceeds the maximum probable flood limit, and malicious aircraft impact. The AP1000 nuclear power plant uses fail safe passive features to mitigate design basis accidents. The passive safety systems are designed to function without safety-grade support systems (such as AC power, component cooling water, service water, compressed air or HVAC). The plant has been designed to protect systems, structures, and components critical to placing the reactor in a safe shutdown condition within the steel containment vessel which is further surrounded by a substantial 'steel concrete' composite shield building. The containment vessel is not affected by external flooding, and the shield building design provides hazard protection beyond that provided by a comparable reinforced concrete structure. The intent of this paper is to demonstrate the robustness of the AP1000 design against extreme events. The paper will focus on the plants ability to withstand extreme external events such as beyond design basis flooding, seismic events, and malicious aircraft impact. The paper will highlight the robustness of the AP1000 nuclear island design including the protection provided by the unique AP1000 composite shield building. (authors)« less

Urban flood early warning systems: approaches to hydrometeorological forecasting and communicating risk

NASA Astrophysics Data System (ADS)

Cranston, Michael; Speight, Linda; Maxey, Richard; Tavendale, Amy; Buchanan, Peter

2015-04-01

One of the main challenges for the flood forecasting community remains the provision of reliable early warnings of surface (or pluvial) flooding. The Scottish Flood Forecasting Service has been developing approaches for forecasting the risk of surface water flooding including capitalising on the latest developments in quantitative precipitation forecasting from the Met Office. A probabilistic Heavy Rainfall Alert decision support tool helps operational forecasters assess the likelihood of surface water flooding against regional rainfall depth-duration estimates from MOGREPS-UK linked to historical short-duration flooding in Scotland. The surface water flood risk is communicated through the daily Flood Guidance Statement to emergency responders. A more recent development is an innovative risk-based hydrometeorological approach that links 24-hour ensemble rainfall forecasts through a hydrological model (Grid-to-Grid) to a library of impact assessments (Speight et al., 2015). The early warning tool - FEWS Glasgow - presents the risk of flooding to people, property and transport across a 1km grid over the city of Glasgow with a lead time of 24 hours. Communication of the risk was presented in a bespoke surface water flood forecast product designed based on emergency responder requirements and trialled during the 2014 Commonwealth Games in Glasgow. The development of new approaches to surface water flood forecasting are leading to improved methods of communicating the risk and better performance in early warning with a reduction in false alarm rates with summer flood guidance in 2014 (67%) compared to 2013 (81%) - although verification of instances of surface water flooding remains difficult. However the introduction of more demanding hydrometeorological capabilities with associated greater levels of uncertainty does lead to an increased demand on operational flood forecasting skills and resources. Speight, L., Cole, S.J., Moore, R.J., Pierce, C., Wright, B., Golding, B., Cranston, M., Tavendale, A., Ghimire, S., and Dhondia, J. (2015) Developing surface water flood forecasting capabilities in Scotland: an operational pilot for the 2014 Commonwealth Games in Glasgow. Journal of Flood Risk Management, In Press.

Flood-inundation and flood-mitigation modeling of the West Branch Wapsinonoc Creek Watershed in West Branch, Iowa

USGS Publications Warehouse

Cigrand, Charles V.

2018-03-26

The U.S. Geological Survey (USGS) in cooperation with the city of West Branch and the Herbert Hoover National Historic Site of the National Park Service assessed flood-mitigation scenarios within the West Branch Wapsinonoc Creek watershed. The scenarios are intended to demonstrate several means of decreasing peak streamflows and improving the conveyance of overbank flows from the West Branch Wapsinonoc Creek and its tributary Hoover Creek where they flow through the city and the Herbert Hoover National Historic Site located within the city.Hydrologic and hydraulic models of the watershed were constructed to assess the flood-mitigation scenarios. To accomplish this, the models used the U.S. Army Corps of Engineers Hydrologic Engineering Center-Hydrologic Modeling System (HEC–HMS) version 4.2 to simulate the amount of runoff and streamflow produced from single rain events. The Hydrologic Engineering Center-River Analysis System (HEC–RAS) version 5.0 was then used to construct an unsteady-state model that may be used for routing streamflows, mapping areas that may be inundated during floods, and simulating the effects of different measures taken to decrease the effects of floods on people and infrastructure.Both models were calibrated to three historic rainfall events that produced peak streamflows ranging between the 2-year and 10-year flood-frequency recurrence intervals at the USGS streamgage (05464942) on Hoover Creek. The historic rainfall events were calibrated by using data from two USGS streamgages along with surveyed high-water marks from one of the events. The calibrated HEC–HMS model was then used to simulate streamflows from design rainfall events of 24-hour duration ranging from a 20-percent to a 1-percent annual exceedance probability. These simulated streamflows were incorporated into the HEC–RAS model.The unsteady-state HEC–RAS model was calibrated to represent existing conditions within the watershed. HEC–RAS model simulations with the existing conditions and streamflows from the design rainfall events were then done to serve as a baseline for evaluating flood-mitigation scenarios. After these simulations were completed, three different flood-mitigation scenarios were developed with HEC–RAS: a detention-storage scenario, a conveyance improvement scenario, and a combination of both. In the detention-storage scenario, four in-channel detention structures were placed upstream from the city of West Branch to attenuate peak streamflows. To investigate possible improvements to conveying floodwaters through the city of West Branch, a section of abandoned railroad embankment and an old truss bridge were removed in the model, because these structures were producing backwater areas during flooding events. The third scenario combines the detention and conveyance scenarios so their joint efficiency could be evaluated. The scenarios with the design rainfall events were run in the HEC–RAS model so their flood-mitigation effects could be analyzed across a wide range of flood magnitudes.

24 CFR 200.926d - Construction requirements.

Code of Federal Regulations, 2012 CFR

2012-04-01

... hazard exposure—(i) Residential structures with basements located in FEMA-designated areas of special flood hazard. The elevation of the lowest floor in structures with basements shall be at or above the... residential structures under regulations for the National Flood Insurance Program (NFIP) (see 44 CFR 60.3...

24 CFR 200.926d - Construction requirements.

Code of Federal Regulations, 2014 CFR

2014-04-01

... hazard exposure—(i) Residential structures with basements located in FEMA-designated areas of special flood hazard. The elevation of the lowest floor in structures with basements shall be at or above the... residential structures under regulations for the National Flood Insurance Program (NFIP) (see 44 CFR 60.3...

24 CFR 200.926d - Construction requirements.

Code of Federal Regulations, 2011 CFR

2011-04-01

... hazard exposure—(i) Residential structures with basements located in FEMA-designated areas of special flood hazard. The elevation of the lowest floor in structures with basements shall be at or above the... residential structures under regulations for the National Flood Insurance Program (NFIP) (see 44 CFR 60.3...

24 CFR 200.926d - Construction requirements.

Code of Federal Regulations, 2013 CFR

2013-04-01

... hazard exposure—(i) Residential structures with basements located in FEMA-designated areas of special flood hazard. The elevation of the lowest floor in structures with basements shall be at or above the... residential structures under regulations for the National Flood Insurance Program (NFIP) (see 44 CFR 60.3...

Overcoming complexities for consistent, continental-scale flood mapping

NASA Astrophysics Data System (ADS)

Smith, Helen; Zaidman, Maxine; Davison, Charlotte

2013-04-01

The EU Floods Directive requires all member states to produce flood hazard maps by 2013. Although flood mapping practices are well developed in Europe, there are huge variations in the scale and resolution of the maps between individual countries. Since extreme flood events are rarely confined to a single country, this is problematic, particularly for the re/insurance industry whose exposures often extend beyond country boundaries. Here, we discuss the challenges of large-scale hydrological and hydraulic modelling, using our experience of developing a 12-country model and set of maps, to illustrate how consistent, high-resolution river flood maps across Europe can be produced. The main challenges addressed include: data acquisition; manipulating the vast quantities of high-resolution data; and computational resources. Our starting point was to develop robust flood-frequency models that are suitable for estimating peak flows for a range of design flood return periods. We used the index flood approach, based on a statistical analysis of historic river flow data pooled on the basis of catchment characteristics. Historical flow data were therefore sourced for each country and collated into a large pan-European database. After a lengthy validation these data were collated into 21 separate analysis zones or regions, grouping smaller river basins according to their physical and climatic characteristics. The very large continental scale basins were each modelled separately on account of their size (e.g. Danube, Elbe, Drava and Rhine). Our methodology allows the design flood hydrograph to be predicted at any point on the river network for a range of return periods. Using JFlow+, JBA's proprietary 2D hydraulic hydrodynamic model, the calculated out-of-bank flows for all watercourses with an upstream drainage area exceeding 50km2 were routed across two different Digital Terrain Models in order to map the extent and depth of floodplain inundation. This generated modelling for a total river length of approximately 250,000km. Such a large-scale, high-resolution modelling exercise is extremely demanding on computational resources and would have been unfeasible without the use of Graphics Processing Units on a network of standard specification gaming computers. Our GPU grid is the world's largest flood-dedicated computer grid. The European river basins were split out into approximately 100 separate hydraulic models and managed individually, although care was taken to ensure flow continuity was maintained between models. The flood hazard maps from the modelling were pieced together using GIS techniques, to provide flood depth and extent information across Europe to a consistent scale and standard. After discussing the methodological challenges, we shall present our flood hazard maps and, from extensive validation work, compare these against historical flow records and observed flood extents.

Impacts of floods on dysentery in Xinxiang city, China, during 2004–2010: a time-series Poisson analysis

PubMed Central

Ni, Wei; Ding, Guoyong; Li, Yifei; Li, Hongkai; Jiang, Baofa

2014-01-01

Background Xinxiang, a city in Henan Province, suffered from frequent floods due to persistent and heavy precipitation from 2004 to 2010. In the same period, dysentery was a common public health problem in Xinxiang, with the proportion of reported cases being the third highest among all the notified infectious diseases. Objectives We focused on dysentery disease consequences of different degrees of floods and examined the association between floods and the morbidity of dysentery on the basis of longitudinal data during the study period. Design A time-series Poisson regression model was conducted to examine the relationship between 10 times different degrees of floods and the monthly morbidity of dysentery from 2004 to 2010 in Xinxiang. Relative risks (RRs) of moderate and severe floods on the morbidity of dysentery were calculated in this paper. In addition, we estimated the attributable contributions of moderate and severe floods to the morbidity of dysentery. Results A total of 7591 cases of dysentery were notified in Xinxiang during the study period. The effect of floods on dysentery was shown with a 0-month lag. Regression analysis showed that the risk of moderate and severe floods on the morbidity of dysentery was 1.55 (95% CI: 1.42–1.670) and 1.74 (95% CI: 1.56–1.94), respectively. The attributable risk proportions (ARPs) of moderate and severe floods to the morbidity of dysentery were 35.53 and 42.48%, respectively. Conclusions This study confirms that floods have significantly increased the risk of dysentery in the study area. In addition, severe floods have a higher proportional contribution to the morbidity of dysentery than moderate floods. Public health action should be taken to avoid and control a potential risk of dysentery epidemics after floods. PMID:25098726

Is Climate Chang Responsible to Recent Urban Flooding in Devloping Cities in Africa? A Case study of Addis Ababa City, Ethiopia

NASA Astrophysics Data System (ADS)

Moges, Semu; Raschid-Sally, Liqa; Gebremichael, Mekonnen

2013-04-01

Cities in Africa show extraordinary expansion of the built environment and imperviousness of the surface condition. Addis Ababa is a case in point, where over the priod of 1984 to 2002, the city asphalted area has increased from 4.72 sq.km (1984) to 27.7 sq.km (2002). Similarly the paved area has expanded five fold from the original 11.1 sq.km, whilst the built environment expanded from 60.1 to 212.7 sq.km. Using hydrological modeling, we demonstrated due to the surface condition change, runoff generation potential has shown significant increase from 28% (in 1984) to 45% (in 2002), showing over 60% change in the runoff volume. The changing condition of the surface is increasing anabtedly, worsening the flooding condition. Similarly, climate change study shows likely increase of precipitation in and around Addis Ababa by about 13 to 17% and comparative increase in flooding. Unlike many cities in Europe, cities in developing countries are confronted with impact emanating from climate change as well as surface condition change. The impact of flooding caused due to the expansion of built environment is found to be more significant in the short term that the climate change, however, the climate change may dominate the long term future of flooding pattern as cities mature towards 2050. Therefore, It is important to view the impacts expansion of built environment and climate change in tandem in future time horizon since the dominance of the impact is different in different temporal scale. In the case of Addis Ababa, we strongly present the following four suggesions: i) the city adminstration re-estabilish the abandoned flood and drainage department of the city as the main flood regulatory and management body working in tandem with Addis Ababa Roads Authority, Water Supply and Sanitation Authority and Urban Planning Authority; ii) The old design guidlines for palnning and design of urban drainage system is not working any more (assumed stationarity condition), we suggest the planning and design criteria of urban drainage systems be immediately revised and incorporated to reflect the new reality of hydrologial non-stationarity; iii) for Addis Ababa City to be Resilient, we suggest implementation of 'Best Managemnt Practice" that incorporates arresting runoff from the source for benefial use, application of runoff treatment practices (open space, infiltration galleries, retardnat ponds, etc) and flood flow control drainage system based on new design criteria, and iv) instituting improved weather forecasting and early warning system.

Flood Control, State Road and Ebner Coulees, La Crosse, Wisconsin, General Design Memorandum. Phase I. Plan Formulation and Hydrology and Draft Environmental Impact Statement.

DTIC Science & Technology

1982-04-01

development of the floodplain by use of appropriate floodplain management techniques to reduce flood losses . h. In the event of future development or...the total annual flood damages in the study area. These losses include physical damages to land, buildings, equipment, and stocks of merchandise as...well as the loss of wages and business profits and the costs of emergency protection. Average annual commercial damages are estimated at $253,000. The

Hydro-Geomorphic Connectivity in Arid Watershed: Anthropogenic Effects and Extreme Flash flood

NASA Astrophysics Data System (ADS)

Egozi, Roey

2017-04-01

Arid watersheds are excellent settings to study water and sediment connectivity because of spars vegetation and the possibility to make clearer links between climate parameters and topographical changes. However different flood event magnitudes may result in different degrees of connectivity. This even gets more complicated when man made modifications to the drainage system are done without considering the outcomes in terms of the potential of flood damage and risks, i.e. in the case of extreme flash floods. Herein we report on the results from two studies conducted in two different small catchments along the dead sea rift: Wadi A Dalia and Wadi Ras Moakif. The studies conducted as part of a larger project aimed at investigating the floods and damages triggered by a rare storm event occurred at the end of October 2015. This storm event covered all of Israel and characterized with rare rainfall depths and intensities as well as floods with rare pick discharges. Observations and field measurements of bed material, river cross sections and water elevation markers were done and statistical analysis has been performed to estimate the exceed probability of the different measured and estimated hydro-climatic values. In Wadi-A-Dalia the coupling of rare rainfall depths over the watershed area which itself was bare due to over grazing result in a major flood. The severe damage caused by this flood was intensified due to the increase of structural hydrologic connectivity, i.e. flood protection canal discharged higher volumes of water collected from small Wadi systems at the same time. In Wadi Ras Moakif the rainfall cells did not produced rare rainfall, but still a major flood occurred over a very short distance of the main channel transporting huge amount of bed material deposited and blocked the main road along the dead sea western coast. In this case the cause was similar - a modification to the drainage system result in increase structural hydrologic connectivity lead to runoff concentration and higher stream power value. The results suggest that in arid watersheds flood protection measures that involve modifications to the drainage system such that the structural hydrologic connectivity improves with the aim to conduit the volume of water away may fail to provide the protection planned and may cause higher damage to infrastructures. Therefore, hydrologic connectivity should become a parameter in flood control design. Moreover, studying hydrologic connectivity in natural landscapes may provide valid solutions for flood control design projects.

Flood-frequency relations for urban streams in Georgia; 1994 update

USGS Publications Warehouse

Inman, Ernest J.

1995-01-01

A statewide study of flood magnitude and frequency in urban areas of Georgia was made to develop methods of estimating flood characteristics at ungaged urban sites. A knowledge of the magnitude and frequency of floods is needed for the design of highway drainage structures, establishing flood- insurance rates, and other uses by urban planners and engineers. A U.S. Geological Survey rainfall-runoff model was calibrated for 65 urban drainage basins ranging in size from 0.04 to 19.1 square miles in 10 urban areas of Georgia. Rainfall-runoff data were collected for a period of 5 to 7 years at each station beginning in 1973 in Metropolitan Atlanta and ending in 1993 in Thomasville, Ga. Calibrated models were used to synthesize long-term annual flood peak discharges for these basins from existing Long-term rainfall records. The 2- to 500-year flood-frequency estimates were developed for each basin by fitting a Pearson Type III frequency distribution curve to the logarithms of these annual peak discharges. Multiple-regression analyses were used to define relations between the station flood-frequency data and several physical basin characteristics, of which drainage area and total impervious area were the most statistically significant. Using theseregression equations and basin characteristics, the magnitude and frequency of floods at ungaged urban basins can be estimated throughout Georgia.

Designing and operating infrastructure for nonstationary flood risk management

NASA Astrophysics Data System (ADS)

Doss-Gollin, J.; Farnham, D. J.; Lall, U.

2017-12-01

Climate exhibits organized low-frequency and regime-like variability at multiple time scales, causing the risk associated with climate extremes such as floods and droughts to vary in time. Despite broad recognition of this nonstationarity, there has been little theoretical development of ideas for the design and operation of infrastructure considering the regime structure of such changes and their potential predictability. We use paleo streamflow reconstructions to illustrate an approach to the design and operation of infrastructure to address nonstationary flood and drought risk. Specifically, we consider the tradeoff between flood control and conservation storage, and develop design and operation principles for allocating these storage volumes considering both a m-year project planning period and a n-year historical sampling record. As n increases, the potential uncertainty in probabilistic estimates of the return periods associated with the T-year extreme event decreases. As the duration m of the future operation period decreases, the uncertainty associated with the occurrence of the T-year event also increases. Finally, given the quasi-periodic nature of the system it may be possible to offer probabilistic predictions of the conditions in the m-year future period, especially if m is small. In the context of such predictions, one can consider that a m-year prediction may have lower bias, but higher variance, than would be associated with using a stationary estimate from the preceding n years. This bias-variance trade-off, and the potential for considering risk management for multiple values of m, provides an interesting system design challenge. We use wavelet-based simulation models in a Bayesian framework to estimate these biases and uncertainty distributions and devise a risk-optimized decision rule for the allocation of flood and conservation storage. The associated theoretical development also provides a methodology for the sizing of storage for new infrastructure under nonstationarity, and an examination of risk adaptation measures which consider both short term and long term options simultaneously.

Design and field test equipment of river water level detection based on ultrasonic sensor and SMS gateway as flood early warning

NASA Astrophysics Data System (ADS)

Sulistyowati, Riny; Sujono, Hari Agus; Musthofa, Ahmad Khamdi

2017-06-01

Due to the high rainfall, flood often occurs in some regions, especially in the area adjacent to the river banks that led to the idea to make the river water level detection system as a flood early warning. Several researches have produced flood detection equipment based on ultrasonic sensors and android as flood early warning system. This paper reported the results of a field test detection equipment to measure the river water level of the Bengawansolo River that was conducted in three villages in the district of Bungah, Dukun, and Manyar in Gresik regency. Tests were conducted simultaneously for 21 hours during heavy rainfall. The test results demonstrated the accuracy of the equipment of 97.28% for all categories of observation. The application of AFD (Android Flood Detection) via android smartphone demonstrated its precision in conveying the information of water level as represented by the status of SAFE, STAND, WARNING, and DANGER. Some charts presented from the analysis of data was derived from the data acquisition time of testing that can be used as an evaluation of flooding at some points prone to flood.

Inventory and mapping of flood inundation using interactive digital image analysis techniques

USGS Publications Warehouse

Rohde, Wayne G.; Nelson, Charles A.; Taranik, J.V.

1979-01-01

LANDSAT digital data and color infra-red photographs were used in a multiphase sampling scheme to estimate the area of agricultural land affected by a flood. The LANDSAT data were classified with a maximum likelihood algorithm. Stratification of the LANDSAT data, prior to classification, greatly reduced misclassification errors. The classification results were used to prepare a map overlay showing the areal extent of flooding. These data also provided statistics required to estimate sample size in a two phase sampling scheme, and provided quick, accurate estimates of areas flooded for the first phase. The measurements made in the second phase, based on ground data and photo-interpretation, were used with two phase sampling statistics to estimate the area of agricultural land affected by flooding These results show that LANDSAT digital data can be used to prepare map overlays showing the extent of flooding on agricultural land and, with two phase sampling procedures, can provide acreage estimates with sampling errors of about 5 percent. This procedure provides a technique for rapidly assessing the areal extent of flood conditions on agricultural land and would provide a basis for designing a sampling framework to estimate the impact of flooding on crop production.

Flood management on the lower Yellow River: hydrological and geomorphological perspectives

NASA Astrophysics Data System (ADS)

Shu, Li; Finlayson, Brian

1993-05-01

The Yellow River, known also as "China's Sorrow", has a long history of channel changes and disastrous floods in its lower reaches. Past channel positions can be identified from historical documentary records and geomorphological and sedimentological evidence. Since 1947, government policy has been aimed at containing the floods within artificial levees and preventing the river from changing its course. Flood control is based on flood-retarding dams and off-stream retention basins as well as artificial levees lining the channel. The design flood for the system has a recurrence interval of only around 60 years and floods of this and larger magnitudes can be generated downstream of the main flood control dams at Sanmenxia and Xiaolangdi. Rapid sedimentation along the river causes problems for storage and has raised the bed of the river some 10 m above the surrounding floodplain. The present management strategy is probably not viable in the long term and to avoid a major disaster a new management approach is required. The most viable option would appear to be to breach the levees at predetermined points coupled with advanced warning and evacuation of the population thus put at risk.

Uncertainty Assessment of Synthetic Design Hydrographs for Gauged and Ungauged Catchments

NASA Astrophysics Data System (ADS)

Brunner, Manuela I.; Sikorska, Anna E.; Furrer, Reinhard; Favre, Anne-Catherine

2018-03-01

Design hydrographs described by peak discharge, hydrograph volume, and hydrograph shape are essential for engineering tasks involving storage. Such design hydrographs are inherently uncertain as are classical flood estimates focusing on peak discharge only. Various sources of uncertainty contribute to the total uncertainty of synthetic design hydrographs for gauged and ungauged catchments. These comprise model uncertainties, sampling uncertainty, and uncertainty due to the choice of a regionalization method. A quantification of the uncertainties associated with flood estimates is essential for reliable decision making and allows for the identification of important uncertainty sources. We therefore propose an uncertainty assessment framework for the quantification of the uncertainty associated with synthetic design hydrographs. The framework is based on bootstrap simulations and consists of three levels of complexity. On the first level, we assess the uncertainty due to individual uncertainty sources. On the second level, we quantify the total uncertainty of design hydrographs for gauged catchments and the total uncertainty of regionalizing them to ungauged catchments but independently from the construction uncertainty. On the third level, we assess the coupled uncertainty of synthetic design hydrographs in ungauged catchments, jointly considering construction and regionalization uncertainty. We find that the most important sources of uncertainty in design hydrograph construction are the record length and the choice of the flood sampling strategy. The total uncertainty of design hydrographs in ungauged catchments depends on the catchment properties and is not negligible in our case.

Identification of Flood Reactivity Regions via the Functional Clustering of Hydrographs

NASA Astrophysics Data System (ADS)

Brunner, Manuela I.; Viviroli, Daniel; Furrer, Reinhard; Seibert, Jan; Favre, Anne-Catherine

2018-03-01

Flood hydrograph shapes contain valuable information on the flood-generation mechanisms of a catchment. To make good use of this information, we express flood hydrograph shapes as continuous functions using a functional data approach. We propose a clustering approach based on functional data for flood hydrograph shapes to identify a set of representative hydrograph shapes on a catchment scale and use these catchment-specific sets of representative hydrographs to establish regions of catchments with similar flood reactivity on a regional scale. We applied this approach to flood samples of 163 medium-size Swiss catchments. The results indicate that three representative hydrograph shapes sufficiently describe the hydrograph shape variability within a catchment and therefore can be used as a proxy for the flood behavior of a catchment. These catchment-specific sets of three hydrographs were used to group the catchments into three reactivity regions of similar flood behavior. These regions were not only characterized by similar hydrograph shapes and reactivity but also by event magnitudes and triggering event conditions. We envision these regions to be useful in regionalization studies, regional flood frequency analyses, and to allow for the construction of synthetic design hydrographs in ungauged catchments. The clustering approach based on functional data which establish these regions is very flexible and has the potential to be extended to other geographical regions or toward the use in climate impact studies.

Comparison of the 2-, 25-, and 100-year recurrence interval floods computed from observed data with the 1995 urban flood-frequency estimating equations for Georgia

USGS Publications Warehouse

Inman, Ernest J.

1997-01-01

Flood-frequency relations were computed for 28 urban stations, for 2-, 25-, and 100-year recurrence interval floods and the computations were compared to corresponding recurrence interval floods computed from the estimating equations from a 1995 investigation. Two stations were excluded from further comparisons or analyses because neither station had a significant flood during the period of observed record. The comparisons, based on the student's t-test statistics at the 0.05 level of significance, indicate that the mean residuals of the 25- and 100-year floods were negatively biased by 26.2 percent and 31.6 percent, respectively, at the 26 stations. However, the mean residuals of the 2-year floods were 2.5 percent lower than the mean of the 2-year floods computed from the equations, and were not significantly biased. The reason for this negative bias is that the period of observed record at the 26 stations was a relatively dry period. At 25 of the 26 stations, the two highest simulated peaks used to develop the estimating equations occurred many years before the observed record began. However, no attempt was made to adjust the estimating equations because higher peaks could occur after the period of observed record and an adjustment to the equations would cause an underestimation of design floods.

Process-based selection of copula types for flood peak-volume relationships in Northwest Austria: a case study

NASA Astrophysics Data System (ADS)

Kohnová, Silvia; Gaál, Ladislav; Bacigál, Tomáš; Szolgay, Ján; Hlavčová, Kamila; Valent, Peter; Parajka, Juraj; Blöschl, Günter

2016-12-01

The case study aims at selecting optimal bivariate copula models of the relationships between flood peaks and flood volumes from a regional perspective with a particular focus on flood generation processes. Besides the traditional approach that deals with the annual maxima of flood events, the current analysis also includes all independent flood events. The target region is located in the northwest of Austria; it consists of 69 small and mid-sized catchments. On the basis of the hourly runoff data from the period 1976- 2007, independent flood events were identified and assigned to one of the following three types of flood categories: synoptic floods, flash floods and snowmelt floods. Flood events in the given catchment are considered independent when they originate from different synoptic situations. Nine commonly-used copula types were fitted to the flood peak - flood volume pairs at each site. In this step, two databases were used: i) a process-based selection of all the independent flood events (three data samples at each catchment) and ii) the annual maxima of the flood peaks and the respective flood volumes regardless of the flood processes (one data sample per catchment). The goodness-of-fit of the nine copula types was examined on a regional basis throughout all the catchments. It was concluded that (1) the copula models for the flood processes are discernible locally; (2) the Clayton copula provides an unacceptable performance for all three processes as well as in the case of the annual maxima; (3) the rejection of the other copula types depends on the flood type and the sample size; (4) there are differences in the copulas with the best fits: for synoptic and flash floods, the best performance is associated with the extreme value copulas; for snowmelt floods, the Frank copula fits the best; while in the case of the annual maxima, no firm conclusion could be made due to the number of copulas with similarly acceptable overall performances. The general conclusion from this case study is that treating flood processes separately is beneficial; however, the usually available sample size in such real life studies is not sufficient to give generally valid recommendations for engineering design tasks.

Coastal and river flood risk analyses for guiding economically optimal flood adaptation policies: a country-scale study for Mexico.

PubMed

Haer, Toon; Botzen, W J Wouter; van Roomen, Vincent; Connor, Harry; Zavala-Hidalgo, Jorge; Eilander, Dirk M; Ward, Philip J

2018-06-13

Many countries around the world face increasing impacts from flooding due to socio-economic development in flood-prone areas, which may be enhanced in intensity and frequency as a result of climate change. With increasing flood risk, it is becoming more important to be able to assess the costs and benefits of adaptation strategies. To guide the design of such strategies, policy makers need tools to prioritize where adaptation is needed and how much adaptation funds are required. In this country-scale study, we show how flood risk analyses can be used in cost-benefit analyses to prioritize investments in flood adaptation strategies in Mexico under future climate scenarios. Moreover, given the often limited availability of detailed local data for such analyses, we show how state-of-the-art global data and flood risk assessment models can be applied for a detailed assessment of optimal flood-protection strategies. Our results show that especially states along the Gulf of Mexico have considerable economic benefits from investments in adaptation that limit risks from both river and coastal floods, and that increased flood-protection standards are economically beneficial for many Mexican states. We discuss the sensitivity of our results to modelling uncertainties, the transferability of our modelling approach and policy implications.This article is part of the theme issue 'Advances in risk assessment for climate change adaptation policy'. © 2018 The Author(s).

The effects of natural and induced short-term floods on four sugarcane accessions

USDA-ARS?s Scientific Manuscript database

A study was initiated at the USDA/ARS Subtropical Horticulture Research Station, Miami, FL to evaluate the potential for flood tolerance in several accessions from Saccharum barberi (Jeswiet) and S. sinense (Roxb. Amend. Jeswiet) sugarcane genera. The experimental design included 4 accessions, Kewal...

Amazon Flooded Forest. Teacher Resource Guide.

ERIC Educational Resources Information Center

Duvall, Todd

This teacher's resource guide was created to accompany the Amazon Flooded Forest exhibit at the Oregon Zoo. The enclosed lessons and activities are designed to extend into several aspects of daily curriculum including science, math, reading, writing, speaking, and geography. The materials are intended for use in grades 3-6 although most activities…

46 CFR 172.245 - Survival conditions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... conditions. A vessel is presumed to survive assumed damage if it meets the following conditions in the final..., and trim must be below the lower edge of an opening through which progressive flooding may take place... inches (50 mm) when the vessel is in the equilibrium position. (e) Progressive flooding. In the design...

46 CFR 172.245 - Survival conditions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... conditions. A vessel is presumed to survive assumed damage if it meets the following conditions in the final..., and trim must be below the lower edge of an opening through which progressive flooding may take place... inches (50 mm) when the vessel is in the equilibrium position. (e) Progressive flooding. In the design...

46 CFR 172.245 - Survival conditions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... conditions. A vessel is presumed to survive assumed damage if it meets the following conditions in the final..., and trim must be below the lower edge of an opening through which progressive flooding may take place... inches (50 mm) when the vessel is in the equilibrium position. (e) Progressive flooding. In the design...

The effect of flooding on mental health: Lessons learned for building resilience

NASA Astrophysics Data System (ADS)

Foudi, Sébastien; Osés-Eraso, Nuria; Galarraga, Ibon

2017-07-01

Risk management and climate adaptation literature focuses mainly on reducing the impacts of, exposure to, and vulnerability to extreme events such as floods and droughts. Posttraumatic stress disorder is one of the most important impacts related to these events, but also a relatively under-researched topic outside original psychopathological contexts. We conduct a survey to investigate the mental stress caused by floods. We focus on hydrological, individual, and collective drivers of posttraumatic stress. We assess stress with flood-specific health scores and the GHQ-12 General Health Questionnaire. Our findings show that the combination of water depth and flood velocity measured via a Hazard Class Index is an important stressor; and that mental health resilience can be significantly improved by providing the population with adequate information. More specifically, the paper shows that psychological distress can be reduced by (i) coordinating awareness of flood risks and flood protection and prevention behavior; (ii) developing the ability to protect oneself from physical, material and intangible damage; (iii) designing simple insurance procedures and protocols for fast recovery; and (iv) learning from previous experiences.

The influence of episodic flooding on a pelagic ecosystem in the East China Sea

NASA Astrophysics Data System (ADS)

Chen, Chung-Chi; Gong, Gwo-Ching; Chou, Wen-Chen; Chung, Chih-Ching; Hsieh, Chih-Hao; Shiah, Fuh-Kwo; Chiang, Kuo-Ping

2017-05-01

This study was designed to determine the effects of flooding on a pelagic ecosystem in the East China Sea (ECS) with a focus on plankton activity and plankton community respiration (CR). In July 2010, a flood occurred in the Changjiang River. As a comparison, a variety of abiotic and biotic parameters were monitored during this flooding event and during a non-flooding period (July 2009). During the flood, the Changjiang diluted water (CDW) zone covered almost two-thirds of the ECS, which was approximately 6 times the area covered during the non-flooding period. The mean nitrate concentration was 3-fold higher during the 2010 flood (6.2 vs. 2.0 µM in 2009). CR was also higher in the 2010 flood: 105.6 mg C m-3 d-1 vs. only 73.2 mg C m-3 d-1 in 2009. The higher CR in 2010 could be attributed to phytoplankton respiration, especially at stations in the CDW zone that were not previously characterized by low sea surface salinity in 2009. In addition, zooplankton (> 330 µm) were another important component contributing to the high CR rate observed during the 2010 flood; this was a period also associated with a significant degree of fCO2 drawdown. These results collectively suggest that the 2010 flood had a significant effect on the carbon balance in the ECS. This effect might become more pronounced in the future, as extreme rainfall and flooding events are predicted to increase in both frequency and magnitude due to climate change.

Flexibility in Flood Management Design: Proactive Planning Under Climate Change Uncertainty

NASA Astrophysics Data System (ADS)

Smet, K.; de Neufville, R.; van der Vlist, M.

2015-12-01

This paper presents an innovative, value-enhancing procedure for effective planning and design of long-lived flood management infrastructure given uncertain future flooding threats due to climate change. Designing infrastructure that can be adapted over time is a method to safeguard the efficacy of current design decisions given uncertainty about rates and future impacts of climate change. This paper explores the value of embedding "options" in a physical structure, where an option is the right but not the obligation to do something at a later date (e.g. over-dimensioning a floodwall foundation now facilitates a future height addition in response to observed increases in sea level; building of extra pump bays in a pumping station now enables the addition of pumping capacity whenever increased precipitation warrants an expansion.) The proposed procedure couples a simulation model that captures future climate induced changes to the hydrologic operating environment of a structure, with an economic model that estimates the lifetime economic performance of alternative investments. The economic model uses Real "In" Options analysis, a type of cash flow analysis that quantifies the implicit value of options and the flexibility they provide. This procedure is demonstrated using replacement planning for the multi-functional pumping station IJmuiden on the North Sea Canal in the Netherlands. Flexibility in design decisions is modelled, varying the size and specific options included in the new structure. Results indicate that the incorporation of options within the structural design has the potential to improve its economic performance, as compared to more traditional, "build it once and build it big" designs where flexibility is not an explicit design criterion. The added value resulting from the incorporation of flexibility varies with the range of future conditions considered, as well as the options examined. This procedure could be applied more broadly to explore investment strategies for the design of other flood management structures.

Hawaii StreamStats; a web application for defining drainage-basin characteristics and estimating peak-streamflow statistics

USGS Publications Warehouse

Rosa, Sarah N.; Oki, Delwyn S.

2010-01-01

Reliable estimates of the magnitude and frequency of floods are necessary for the safe and efficient design of roads, bridges, water-conveyance structures, and flood-control projects and for the management of flood plains and flood-prone areas. StreamStats provides a simple, fast, and reproducible method to define drainage-basin characteristics and estimate the frequency and magnitude of peak discharges in Hawaii?s streams using recently developed regional regression equations. StreamStats allows the user to estimate the magnitude of floods for streams where data from stream-gaging stations do not exist. Existing estimates of the magnitude and frequency of peak discharges in Hawaii can be improved with continued operation of existing stream-gaging stations and installation of additional gaging stations for areas where limited stream-gaging data are available.

Revision to flood hazard evaluation for the Savannah River Site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buckley, R.; Werth, D.

Requirements for the Natural Phenomena Hazard (NPH) mitigation for new and existing Department of Energy (DOE) facilities are outlined in DOE Order 420.1. This report examines the hazards posed by potential flooding and represents an update to two previous reports. The facility-specific probabilistic flood hazard curve is defined as the water elevation for each annual probability of precipitation occurrence (or inversely, the return period in years). New design hyetographs for both 6-hr and 24-hr precipitation distributions were used in conjunction with hydrological models of various basins within the Savannah River Site (SRS). For numerous locations of interest, peak flow dischargemore » and flood water elevation were determined. In all cases, the probability of flooding of these facilities for a 100,000 year precipitation event is negligible.« less

Information Communication using Knowledge Engine on Flood Issues

NASA Astrophysics Data System (ADS)

Demir, I.; Krajewski, W. F.

2012-04-01

The Iowa Flood Information System (IFIS) is a web-based platform developed by the Iowa Flood Center (IFC) to provide access to and visualization of flood inundation maps, real-time flood conditions, flood forecasts both short-term and seasonal, and other flood-related data for communities in Iowa. The system is designed for use by general public, often people with no domain knowledge and poor general science background. To improve effective communication with such audience, we have introduced a new way in IFIS to get information on flood related issues - instead of by navigating within hundreds of features and interfaces of the information system and web-based sources-- by providing dynamic computations based on a collection of built-in data, analysis, and methods. The IFIS Knowledge Engine connects to distributed sources of real-time stream gauges, and in-house data sources, analysis and visualization tools to answer questions grouped into several categories. Users will be able to provide input based on the query within the categories of rainfall, flood conditions, forecast, inundation maps, flood risk and data sensors. Our goal is the systematization of knowledge on flood related issues, and to provide a single source for definitive answers to factual queries. Long-term goal of this knowledge engine is to make all flood related knowledge easily accessible to everyone, and provide educational geoinformatics tool. The future implementation of the system will be able to accept free-form input and voice recognition capabilities within browser and mobile applications. We intend to deliver increasing capabilities for the system over the coming releases of IFIS. This presentation provides an overview of our Knowledge Engine, its unique information interface and functionality as an educational tool, and discusses the future plans for providing knowledge on flood related issues and resources.

Adaptation to flooding during emergence and seedling growth in rice and weeds, and implications for crop establishment.

PubMed

Ismail, Abdelbagi M; Johnson, David E; Ella, Evangelina S; Vergara, Georgina V; Baltazar, Aurora M

2012-01-01

Direct seeding of rice is being adopted in rainfed and irrigated lowland ecosystems because it reduces labour costs in addition to other benefits. However, early flooding due to uneven fields or rainfall slows down seed germination and hinders crop establishment. Conversely, early flooding helps suppress weeds and reduces the costs of manual weeding and/or dependence on herbicides; however, numerous weed species are adapted to lowlands and present challenges for the use of flooding to control weeds. Advancing knowledge on the mechanisms of tolerance of flooding during germination and early growth in rice and weeds could facilitate the development of improved rice varieties and effective weed management practices for direct-seeded rice. Rice genotypes with a greater ability to germinate and establish in flooded soils were identified, providing opportunities to develop varieties suitable for direct seeding in flooded soils. Tolerance of flooding in these genotypes was mostly attributed to traits associated with better ability to mobilize stored carbohydrates and anaerobic metabolism. Limited studies were undertaken in weeds associated with lowland rice systems. Remaining studies compared rice and weeds and related weed species such as Echinochloa crus-galli and E. colona or compared ecotypes of the same species of Cyperus rotundus adapted to either aerobic or flooded soils. Tolerant weeds and rice genotypes mostly developed similar adaptive traits that allow them to establish in flooded fields, including the ability to germinate and elongate faster under hypoxia, mobilize stored starch reserves and generate energy through fermentation pathways. Remarkably, some weeds developed additional traits such as larger storage tubers that enlarge further in deeper flooded soils (C. rotundus). Unravelling the mechanisms involved in adaptation to flooding will help design management options that will allow tolerant rice genotypes to adequately establish in flooded soils while simultaneously suppressing weeds.

Real Time Flood Alert System (RTFAS) for Puerto Rico

USGS Publications Warehouse

Lopez-Trujillo, Dianne

2010-01-01

The Real Time Flood Alert System is a web-based computer program, developed as a data integration tool, and designed to increase the ability of emergency managers to rapidly and accurately predict flooding conditions of streams in Puerto Rico. The system includes software and a relational database to determine the spatial and temporal distribution of rainfall, water levels in streams and reservoirs, and associated storms to determine hazardous and potential flood conditions. The computer program was developed as part of a cooperative agreement between the U.S. Geological Survey Caribbean Water Science Center and the Puerto Rico Emergency Management Agency, and integrates information collected and processed by these two agencies and the National Weather Service.

Optimal Spatial Design of Capacity and Quantity of Rainwater Catchment Systems for Urban Flood Mitigation

NASA Astrophysics Data System (ADS)

Huang, C.; Hsu, N.

2013-12-01

This study imports Low-Impact Development (LID) technology of rainwater catchment systems into a Storm-Water runoff Management Model (SWMM) to design the spatial capacity and quantity of rain barrel for urban flood mitigation. This study proposes a simulation-optimization model for effectively searching the optimal design. In simulation method, we design a series of regular spatial distributions of capacity and quantity of rainwater catchment facilities, and thus the reduced flooding circumstances using a variety of design forms could be simulated by SWMM. Moreover, we further calculate the net benefit that is equal to subtract facility cost from decreasing inundation loss and the best solution of simulation method would be the initial searching solution of the optimization model. In optimizing method, first we apply the outcome of simulation method and Back-Propagation Neural Network (BPNN) for developing a water level simulation model of urban drainage system in order to replace SWMM which the operating is based on a graphical user interface and is hard to combine with optimization model and method. After that we embed the BPNN-based simulation model into the developed optimization model which the objective function is minimizing the negative net benefit. Finally, we establish a tabu search-based algorithm to optimize the planning solution. This study applies the developed method in Zhonghe Dist., Taiwan. Results showed that application of tabu search and BPNN-based simulation model into the optimization model not only can find better solutions than simulation method in 12.75%, but also can resolve the limitations of previous studies. Furthermore, the optimized spatial rain barrel design can reduce 72% of inundation loss according to historical flood events.

Optimization of storage tank locations in an urban stormwater drainage system using a two-stage approach.

PubMed

Wang, Mingming; Sun, Yuanxiang; Sweetapple, Chris

2017-12-15

Storage is important for flood mitigation and non-point source pollution control. However, to seek a cost-effective design scheme for storage tanks is very complex. This paper presents a two-stage optimization framework to find an optimal scheme for storage tanks using storm water management model (SWMM). The objectives are to minimize flooding, total suspended solids (TSS) load and storage cost. The framework includes two modules: (i) the analytical module, which evaluates and ranks the flooding nodes with the analytic hierarchy process (AHP) using two indicators (flood depth and flood duration), and then obtains the preliminary scheme by calculating two efficiency indicators (flood reduction efficiency and TSS reduction efficiency); (ii) the iteration module, which obtains an optimal scheme using a generalized pattern search (GPS) method based on the preliminary scheme generated by the analytical module. The proposed approach was applied to a catchment in CZ city, China, to test its capability in choosing design alternatives. Different rainfall scenarios are considered to test its robustness. The results demonstrate that the optimal framework is feasible, and the optimization is fast based on the preliminary scheme. The optimized scheme is better than the preliminary scheme for reducing runoff and pollutant loads under a given storage cost. The multi-objective optimization framework presented in this paper may be useful in finding the best scheme of storage tanks or low impact development (LID) controls. Copyright © 2017 Elsevier Ltd. All rights reserved.

Application of HEC-RAS for flood forecasting in perched river-A case study of hilly region, China

NASA Astrophysics Data System (ADS)

Sun, Pingping; Wang, Shuqian; Gan, Hong; Liu, Bin; Jia, Ling

2017-04-01

Flooding in small and medium rivers are seriously threatening the safety of human beings’ life and property. The simulation forecasting of the river flood and bank risk in hilly region has gradually become a hotspot. At present, there are few studies on the simulation of hilly perched river, especially in the case of lacking section flow data. And the method of how to determine the position of the levee breach along the river bank is not much enough. Based on the characteristics of the sections in hilly perched river, an attempt is applied in this paper which establishes the correlation between the flow profile computed by HEC-RAS model and the river bank. A hilly perched river in Lingshi County, Shanxi Province of China, is taken as the study object, the levee breach positions along the bank are simulated under four different design storm. The results show that the flood control standard of upper reach is high, which can withstand the design storm of 100 years. The current standard of lower reach is low, which is the flooding channel with high frequency. As the standard of current channel between the 2rd and the 11th section is low, levee along that channel of the river bank is considered to be heighten and reinforced. The study results can provide some technical support for flood proofing in hilly region and some reference for the reinforcement of river bank.

Single well tracer method to evaluate enhanced recovery

DOEpatents

Sheely, Jr., Clyde Q.; Baldwin, Jr., David E.

1978-01-01

Data useful to evaluate the effectiveness of or to design an enhanced recovery process (the recovery process involving mobilizing and moving hydrocarbons through a hydrocarbon-bearing subterranean formation from an injection well to a production well by injecting a mobilizing fluid into the injection well) are obtained by a process which comprises sequentially: determining hydrocarbon saturation in the formation in a volume in the formation near a well bore penetrating the formation, injecting sufficient of the mobilizing fluid to mobilize and move hydrocarbons from a volume in the formation near the well bore penetrating the formation, and determining by the single well tracer method a hydrocarbon saturation profile in a volume from which hydrocarbons are moved. The single well tracer method employed is disclosed by U.S. Pat. No. 3,623,842. The process is useful to evaluate surfactant floods, water floods, polymer floods, CO.sub.2 floods, caustic floods, micellar floods, and the like in the reservoir in much less time at greatly reduced costs, compared to conventional multi-well pilot test.

The Study on Flood Reduction and Securing Instreamflow by applying Decentralized Rainwater Retention Facilities for Chunggyechun in Seoul of Korea

NASA Astrophysics Data System (ADS)

Park, J. H.; Jun, S. M.; Park, C. G.

2014-12-01

Recently abnormal climate phenomena and urbanization recently causes the changes of the hydrological environment. To restore the hydrological cycle in urban area some fundamental solutions such as decentralized rainwater management system and Low Impact Development (LID) techniques may be choosed. In this study, SWMM 5 was used to analyze the effects of decentralized stormwater retention for preventing the urban flood and securing the instreamflow. The Chunggyechun stream watershed(21.29㎢) which is located in Seoul city(Korea) and fully developed as urban area was selected as the study watershed, and the runoff characteristics of urban stream with various methods of LID techniques (Permeable pavement, small rainwater storage tank, large rainwater storage tank) were analyzed. By the simulation results, the permeability of pavement materials and detention storage at the surface soil layer make high effect to the flood discharge, and the initial rainfall retention at the rainwater storage tank effected to reduce the flood peak. The peak discharge was decreased as 22% for the design precipitation. Moreover the instreamflow was increased as 55% by using adequate LID techniques These kind of data could be used as the basis data for designing urban flood prevention facilities, urban regeneration planning in the view of the integrated watershed management.

Analysing urban resilience through alternative stormwater management options: application of the conceptual Spatial Decision Support System model at the neighbourhood scale.

PubMed

Balsells, M; Barroca, B; Amdal, J R; Diab, Y; Becue, V; Serre, D

2013-01-01

Recent changes in cities and their environments, caused by rapid urbanisation and climate change, have increased both flood probability and the severity of flooding. Consequently, there is a need for all cities to adapt to climate and socio-economic changes by developing new strategies for flood risk management. Following a risk paradigm shift from traditional to more integrated approaches, and considering the uncertainties of future urban development, one of the main emerging tasks for city managers becomes the development of resilient cities. However, the meaning of the resilience concept and its operability is still not clear. The goal of this research is to study how urban engineering and design disciplines can improve resilience to floods in urban neighbourhoods. This paper presents the conceptual Spatial Decision Support System (DS3) model which we consider a relevant tool to analyse and then implement resilience into neighbourhood design. Using this model, we analyse and discuss alternative stormwater management options at the neighbourhood scale in two specific areas: Rotterdam and New Orleans. The results obtained demonstrate that the DS3 model confirmed in its framework analysis that stormwater management systems can positively contribute to the improved flood resilience of a neighbourhood.

The physical vulnerability of elements at risk: a methodology based on fluid and classical mechanics

NASA Astrophysics Data System (ADS)

Mazzorana, B.; Fuchs, S.; Levaggi, L.

2012-04-01

The impacts of the flood events occurred in autumn 2011 in the Italian regions Liguria and Tuscany revived the engagement of the public decision makers to enhance in synergy flood control and land use planning. In this context, the design of efficient flood risk mitigation strategies and their subsequent implementation critically relies on a careful vulnerability analysis of both, the immobile and mobile elements at risk potentially exposed to flood hazards. Based on fluid and classical mechanics notions we developed computation schemes enabling for a dynamic vulnerability and risk analysis facing a broad typological variety of elements at risk. The methodological skeleton consists of (1) hydrodynamic computation of the time-varying flood intensities resulting for each element at risk in a succession of loading configurations; (2) modelling the mechanical response of the impacted elements through static, elasto-static and dynamic analyses; (3) characterising the mechanical response through proper structural damage variables and (4) economic valuation of the expected losses as a function of the quantified damage variables. From a computational perspective we coupled the description of the hydrodynamic flow behaviour and the induced structural modifications of the elements at risk exposed. Valuation methods, suitable to support a correct mapping from the value domains of the physical damage variables to the economic loss values are discussed. In such a way we target to complement from a methodological perspective the existing, mainly empirical, vulnerability and risk assessment approaches to refine the conceptual framework of the cost-benefit analysis. Moreover, we aim to support the design of effective flood risk mitigation strategies by diminishing the main criticalities within the systems prone to flood risk.

Modelling the effectiveness of grass buffer strips in managing muddy floods under a changing climate

NASA Astrophysics Data System (ADS)

Mullan, Donal; Vandaele, Karel; Boardman, John; Meneely, John; Crossley, Laura H.

2016-10-01

Muddy floods occur when rainfall generates runoff on agricultural land, detaching and transporting sediment into the surrounding natural and built environment. In the Belgian Loess Belt, muddy floods occur regularly and lead to considerable economic costs associated with damage to property and infrastructure. Mitigation measures designed to manage the problem have been tested in a pilot area within Flanders and were found to be cost-effective within three years. This study assesses whether these mitigation measures will remain effective under a changing climate. To test this, the Water Erosion Prediction Project (WEPP) model was used to examine muddy flooding diagnostics (precipitation, runoff, soil loss and sediment yield) for a case study hillslope in Flanders where grass buffer strips are currently used as a mitigation measure. The model was run for present day conditions and then under 33 future site-specific climate scenarios. These future scenarios were generated from three earth system models driven by four representative concentration pathways and downscaled using quantile mapping and the weather generator CLIGEN. Results reveal that under the majority of future scenarios, muddy flooding diagnostics are projected to increase, mostly as a consequence of large scale precipitation events rather than mean changes. The magnitude of muddy flood events for a given return period is also generally projected to increase. These findings indicate that present day mitigation measures may have a reduced capacity to manage muddy flooding given the changes imposed by a warming climate with an enhanced hydrological cycle. Revisions to the design of existing mitigation measures within existing policy frameworks are considered the most effective way to account for the impacts of climate change in future mitigation planning.

Potentialities of ensemble strategies for flood forecasting over the Milano urban area

NASA Astrophysics Data System (ADS)

Ravazzani, Giovanni; Amengual, Arnau; Ceppi, Alessandro; Homar, Víctor; Romero, Romu; Lombardi, Gabriele; Mancini, Marco

2016-08-01

Analysis of ensemble forecasting strategies, which can provide a tangible backing for flood early warning procedures and mitigation measures over the Mediterranean region, is one of the fundamental motivations of the international HyMeX programme. Here, we examine two severe hydrometeorological episodes that affected the Milano urban area and for which the complex flood protection system of the city did not completely succeed. Indeed, flood damage have exponentially increased during the last 60 years, due to industrial and urban developments. Thus, the improvement of the Milano flood control system needs a synergism between structural and non-structural approaches. First, we examine how land-use changes due to urban development have altered the hydrological response to intense rainfalls. Second, we test a flood forecasting system which comprises the Flash-flood Event-based Spatially distributed rainfall-runoff Transformation, including Water Balance (FEST-WB) and the Weather Research and Forecasting (WRF) models. Accurate forecasts of deep moist convection and extreme precipitation are difficult to be predicted due to uncertainties arising from the numeric weather prediction (NWP) physical parameterizations and high sensitivity to misrepresentation of the atmospheric state; however, two hydrological ensemble prediction systems (HEPS) have been designed to explicitly cope with uncertainties in the initial and lateral boundary conditions (IC/LBCs) and physical parameterizations of the NWP model. No substantial differences in skill have been found between both ensemble strategies when considering an enhanced diversity of IC/LBCs for the perturbed initial conditions ensemble. Furthermore, no additional benefits have been found by considering more frequent LBCs in a mixed physics ensemble, as ensemble spread seems to be reduced. These findings could help to design the most appropriate ensemble strategies before these hydrometeorological extremes, given the computational cost of running such advanced HEPSs for operational purposes.

Flood Risk and Probabilistic Benefit Assessment to Support Management of Flood-Prone Lands: Evidence From Candaba Floodplains, Philippines

NASA Astrophysics Data System (ADS)

Juarez, A. M.; Kibler, K. M.; Sayama, T.; Ohara, M.

2016-12-01

Flood management decision-making is often supported by risk assessment, which may overlook the role of coping capacity and the potential benefits derived from direct use of flood-prone land. Alternatively, risk-benefit analysis can support floodplain management to yield maximum socio-ecological benefits for the minimum flood risk. We evaluate flood risk-probabilistic benefit tradeoffs of livelihood practices compatible with direct human use of flood-prone land (agriculture/wild fisheries) and nature conservation (wild fisheries only) in Candaba, Philippines. Located north-west to Metro Manila, Candaba area is a multi-functional landscape that provides a temporally-variable mix of possible land uses, benefits and ecosystem services of local and regional value. To characterize inundation from 1.3- to 100-year recurrence intervals we couple frequency analysis with rainfall-runoff-inundation modelling and remotely-sensed data. By combining simulated probabilistic floods with both damage and benefit functions (e.g. fish capture and rice yield with flood intensity) we estimate potential damages and benefits over varying probabilistic flood hazards. We find that although direct human uses of flood-prone land are associated with damages, for all the investigated magnitudes of flood events with different frequencies, the probabilistic benefits ( 91 million) exceed risks by a large margin ( 33 million). Even considering risk, probabilistic livelihood benefits of direct human uses far exceed benefits provided by scenarios that exclude direct "risky" human uses (difference of 85 million). In addition, we find that individual coping strategies, such as adapting crop planting periods to the flood pulse or fishing rather than cultivating rice in the wet season, minimize flood losses ( 6 million) while allowing for valuable livelihood benefits ($ 125 million) in flood-prone land. Analysis of societal benefits and local capacities to cope with regular floods demonstrate the relevance of accounting for the full range of flood events and their relation to both potential damages and benefits in risk assessments. Management measures may thus be designed to reflect local contexts and support benefits of natural hydrologic processes, while minimizing flood damage.

Dynamic Flood Vulnerability Mapping with Google Earth Engine

NASA Astrophysics Data System (ADS)

Tellman, B.; Kuhn, C.; Max, S. A.; Sullivan, J.

2015-12-01

Satellites capture the rate and character of environmental change from local to global levels, yet integrating these changes into flood exposure models can be cost or time prohibitive. We explore an approach to global flood modeling by leveraging satellite data with computing power in Google Earth Engine to dynamically map flood hazards. Our research harnesses satellite imagery in two main ways: first to generate a globally consistent flood inundation layer and second to dynamically model flood vulnerability. Accurate and relevant hazard maps rely on high quality observation data. Advances in publicly available spatial, spectral, and radar data together with cloud computing allow us to improve existing efforts to develop a comprehensive flood extent database to support model training and calibration. This talk will demonstrate the classification results of algorithms developed in Earth Engine designed to detect flood events by combining observations from MODIS, Landsat 8, and Sentinel-1. Our method to derive flood footprints increases the number, resolution, and precision of spatial observations for flood events both in the US, recorded in the NCDC (National Climatic Data Center) storm events database, and globally, as recorded events from the Colorado Flood Observatory database. This improved dataset can then be used to train machine learning models that relate spatial temporal flood observations to satellite derived spatial temporal predictor variables such as precipitation, antecedent soil moisture, and impervious surface. This modeling approach allows us to rapidly update models with each new flood observation, providing near real time vulnerability maps. We will share the water detection algorithms used with each satellite and discuss flood detection results with examples from Bihar, India and the state of New York. We will also demonstrate how these flood observations are used to train machine learning models and estimate flood exposure. The final stage of our comprehensive approach to flood vulnerability couples inundation extent with social data to determine which flood exposed communities have the greatest propensity for loss. Specifically, by linking model outputs to census derived social vulnerability estimates (Indian and US, respectively) to predict how many people are at risk.

Designing Financial Instruments for Rapid Flood Response Using Remote Sensed and Archival Hazard and Exposure Information

NASA Astrophysics Data System (ADS)

Lall, U.; Allaire, M.; Ceccato, P.; Haraguchi, M.; Cian, F.; Bavandi, A.

2017-12-01

Catastrophic floods can pose a significant challenge for response and recovery. A key bottleneck in the speed of response is the availability of funds to a country or regions finance ministry to mobilize resources. Parametric instruments, where the release of funs is tied to the exceedance of a specified index or threshold, rather than to loss verification are well suited for this purpose. However, designing and appropriate index, that is not subject to manipulation and accurately reflects the need is a challenge, especially in developing countries which have short hydroclimatic and loss records, and where rapid land use change has led to significant changes in exposure and hydrology over time. The use of long records of rainfall from climate re-analyses, flooded area and land use from remote sensing to design and benchmark a parametric index considering the uncertainty and representativeness of potential loss is explored with applications to Bangladesh and Thailand. Prospects for broader applicability and limitations are discussed.

Quality control of the RMS US flood model

NASA Astrophysics Data System (ADS)

Jankowfsky, Sonja; Hilberts, Arno; Mortgat, Chris; Li, Shuangcai; Rafique, Farhat; Rajesh, Edida; Xu, Na; Mei, Yi; Tillmanns, Stephan; Yang, Yang; Tian, Ye; Mathur, Prince; Kulkarni, Anand; Kumaresh, Bharadwaj Anna; Chaudhuri, Chiranjib; Saini, Vishal

2016-04-01

The RMS US flood model predicts the flood risk in the US with a 30 m resolution for different return periods. The model is designed for the insurance industry to estimate the cost of flood risk for a given location. Different statistical, hydrological and hydraulic models are combined to develop the flood maps for different return periods. A rainfall-runoff and routing model, calibrated with observed discharge data, is run with 10 000 years of stochastic simulated precipitation to create time series of discharge and surface runoff. The 100, 250 and 500 year events are extracted from these time series as forcing for a two-dimensional pluvial and fluvial inundation model. The coupling of all the different models which are run on the large area of the US implies a certain amount of uncertainty. Therefore, special attention is paid to the final quality control of the flood maps. First of all, a thorough quality analysis of the Digital Terrain model and the river network was done, as the final quality of the flood maps depends heavily on the DTM quality. Secondly, the simulated 100 year discharge in the major river network (600 000 km) is compared to the 100 year discharge derived using extreme value distribution of all USGS gauges with more than 20 years of peak values (around 11 000 gauges). Thirdly, for each gauge the modelled flood depth is compared to the depth derived from the USGS rating curves. Fourthly, the modelled flood depth is compared to the base flood elevation given in the FEMA flood maps. Fifthly, the flood extent is compared to the FEMA flood extent. Then, for historic events we compare flood extents and flood depths at given locations. Finally, all the data and spatial layers are uploaded on geoserver to facilitate the manual investigation of outliers. The feedback from the quality control is used to improve the model and estimate its uncertainty.

Paleohydrologic techniques used to define the spatial occurrence of floods

USGS Publications Warehouse

Jarrett, R.D.

1990-01-01

Defining the cause and spatial characteristics of floods may be difficult because of limited streamflow and precipitation data. New paleohydrologic techniques that incorporate information from geomorphic, sedimentologic, and botanic studies provide important supplemental information to define homogeneous hydrologic regions. These techniques also help to define the spatial structure of rainstorms and floods and improve regional flood-frequency estimates. The occurrence and the non-occurrence of paleohydrologic evidence of floods, such as flood bars, alluvial fans, and tree scars, provide valuable hydrologic information. The paleohydrologic research to define the spatial characteristics of floods improves the understanding of flood hydrometeorology. This research was used to define the areal extent and contributing drainage area of flash floods in Colorado. Also, paleohydrologic evidence was used to define the spatial boundaries for the Colorado foothills region in terms of the meteorologic cause of flooding and elevation. In general, above 2300 m, peak flows are caused by snowmelt. Below 2300 m, peak flows primarily are caused by rainfall. The foothills region has an upper elevation limit of about 2300 m and a lower elevation limit of about 1500 m. Regional flood-frequency estimates that incorporate the paleohydrologic information indicate that the Big Thompson River flash flood of 1976 had a recurrence interval of approximately 10,000 years. This contrasts markedly with 100 to 300 years determined by using conventional hydrologic analyses. Flood-discharge estimates based on rainfall-runoff methods in the foothills of Colorado result in larger values than those estimated with regional flood-frequency relations, which are based on long-term streamflow data. Preliminary hydrologic and paleohydrologic research indicates that intense rainfall does not occur at higher elevations in other Rocky Mountain states and that the highest elevations for rainfall-producing floods vary by latitude. The study results have implications for floodplain management and design of hydraulic structures in the mountains of Colorado and other Rocky Mountain States. ?? 1990.

In Vitro Flooding of a Childhood Posttraumatic Stress Disorder.

ERIC Educational Resources Information Center

Saigh, Philip A.

1987-01-01

An in vitro flooding package was used to treat the posttraumatic stress disorder of a 10-year-old girl. Traumatic scenes were identified and stimulus and response imagery cues were presented according to a multiple baseline across traumatic scenes design. Postreatment and follow-up assessment revealed the positive influence of the treatment.…

12 CFR 22.2 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... building or mobile home that is located or to be located in a special flood hazard area in which flood... Management Agency. (g) Mobile home means a structure, transportable in one or more sections, that is built on a permanent chassis and designed for use with or without a permanent foundation when attached to the...

12 CFR 760.2 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... building or mobile home that is located or to be located in a special flood hazard area in which flood... Management Agency. (g) Mobile home means a structure, transportable in one or more sections, that is built on a permanent chassis and designed for use with or without a permanent foundation when attached to the...

12 CFR 614.4925 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... mobile home that is located or to be located in a special flood hazard area in which flood insurance is... Agency. (e) Mobile home means a structure, transportable in one or more sections, that is built on a permanent chassis and designed for use with or without a permanent foundation when attached to the required...

Model Studies of the Portugues and Bucana Rivers Channelization, Puerto Rico. Hydraulic Model Investigation.

DTIC Science & Technology

1978-05-01

Two 1:30-scale physical hydraulic models of the Portugues and Bucana Rivers were used to determine the adequacy of the original designs for the flood...transmit all expected flood releases from the proposed Portugues and Cerrillos Dams. Modifications to transitions at entrances to the high-velocity

75 FR 24723 - Agency Information Collection Activities: Proposed Collection; Comment Request, 1660-0037...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-05

... Insurance Program Maps (Spanish). SUMMARY: The Federal Emergency Management Agency, as part of its... Flood Insurance Program Maps (Spanish). Abstract: FEMA Forms 086-0-22 and 086-0-22A are designed to...,389 Single Residential Lot or Structure Amendments to National Flood Insurance Program Maps (Spanish...

EFFECTS OF FLOOD PULSES ON NITRIFICATION RATES IN UPPER MISSISSIPPI RIVER FORESTED FLOODPLAINS, 2ND PRESENTATION IN 2007

EPA Science Inventory

Presentation is designed to enlighten the interested masses about potentials in nutrient trading and ecosystem services in our great river floodplain ecosystems. It is not intended for policy, rather to stimulate thought on the importance of natural flooding regimes and how to b...

33 CFR 222.2 - Acquisition of lands downstream from spillways for hydrologic safety purposes.

Code of Federal Regulations, 2011 CFR

2011-07-01

... CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE ENGINEERING AND DESIGN § 222.2... depth. (iii) Flood duration. (iv) Velocities. (v) Debris and erosion. (2) Determine the combinations of... hazardous and non-hazardous. Non-hazardous areas are defined as those areas where: (i) Flood depths are...

Flood Study of Warren Brook in Alstead and Cold River in Alstead, Langdon, and Walpole, New Hampshire, 2005

USGS Publications Warehouse

Flynn, Robert H.

2006-01-01

This report presents water-surface elevations and profiles as determined using the U.S. Army Corps of Engineers (USACE) one-dimensional Hydrologic Engineering Center River Analysis System, also known as HEC-RAS. Steady flow water-surface profiles were developed for two stream reaches: the Cold River from its confluence with the Connecticut River in Walpole, through Alstead to the McDermott Bridge in Langdon, NH, and Warren Brook from its confluence with the Cold River to Warren Lake in Alstead, NH. Flood events of a magnitude, which are expected to be equaled or exceeded once on the average during any 10-, 50-, 100-, or 500-year period (recurrence interval), were modeled using HEC-RAS as these flood events are recognized as being significant for flood-plain management, determination of flood insurance rates, and design of structures such as bridges and culverts. These flood events are referred to as the 10-, 50-, 100-, and 500-year floods and have a 10-, 2-, 1-, and 0.2-percent chance, respectively, of being equaled or exceeded during any year. The recurrence intervals represent the long-term average between floods of a specific magnitude. The risk of experiencing rare floods at short intervals or within the same year increases when periods greater than one year are considered. The analyses in this study reflect the flooding potentials based on conditions existing in the communities of Walpole, Alstead and Langdon at the time of completion of this study.

Natural Flood Management Plus: Scaling Up Nature Based Solutions to Larger Catchments

NASA Astrophysics Data System (ADS)

Quinn, Paul; Nicholson, Alex; Adams, Russ

2017-04-01

It has been established that networks NFM features, such as ponds and wetlands, can have a significant effect on flood flow and pollution at local scales (less than 10km2). However, it is much less certain that NFM and NBS can impact at larger scales and protect larger cities. This is especially true for recent storms in the UK such as storm Desmond that caused devastation across the north of England. It is possible using observed rainfall and runoff data to estimate the amounts of storage that would be required to impact on extreme flood events. Here we will how a toolkit that will estimate the amount of storage that can be accrued through a dense networks of NFM features. The analysis suggest that the use of many hundreds of small NFM features can have a significant impact on peak flow, however we still require more storage in order to address extreme events and to satisfy flood engineers who may propose more traditional flood defences. We will also show case studies of larger NFM feature positioned on flood plains that can store significantly more flood flow. Examples designs of NFM plus feature will be shown. The storage aggregation tool will then show the degree to which storing large amounts of flood flow in NFM plus features can contribute to flood management and estimate the likely costs. Together smaller and larger NFM features if used together can produce significant flood storage and at a much lower cost than traditional schemes.

Nonstationary decision model for flood risk decision scaling

NASA Astrophysics Data System (ADS)

Spence, Caitlin M.; Brown, Casey M.

2016-11-01

Hydroclimatic stationarity is increasingly questioned as a default assumption in flood risk management (FRM), but successor methods are not yet established. Some potential successors depend on estimates of future flood quantiles, but methods for estimating future design storms are subject to high levels of uncertainty. Here we apply a Nonstationary Decision Model (NDM) to flood risk planning within the decision scaling framework. The NDM combines a nonstationary probability distribution of annual peak flow with optimal selection of flood management alternatives using robustness measures. The NDM incorporates structural and nonstructural FRM interventions and valuation of flows supporting ecosystem services to calculate expected cost of a given FRM strategy. A search for the minimum-cost strategy under incrementally varied representative scenarios extending across the plausible range of flood trend and value of the natural flow regime discovers candidate FRM strategies that are evaluated and compared through a decision scaling analysis (DSA). The DSA selects a management strategy that is optimal or close to optimal across the broadest range of scenarios or across the set of scenarios deemed most likely to occur according to estimates of future flood hazard. We illustrate the decision framework using a stylized example flood management decision based on the Iowa City flood management system, which has experienced recent unprecedented high flow episodes. The DSA indicates a preference for combining infrastructural and nonstructural adaptation measures to manage flood risk and makes clear that options-based approaches cannot be assumed to be "no" or "low regret."

Design and Flood Control Assessment of 5MWp Fishing and Photovoltaic Power Project in Xinghua City

NASA Astrophysics Data System (ADS)

Guo, Liuchao; Hu, Xiaodong; Su, Yuyan; Wu, Peipei; Weng, Songgan

2017-12-01

In order to reduce coal consumption in Jiangsu Province and develop new energy sources, considering on the distribution of geology, solar energy resources, traffic and grid connection in Xinghua City, the aim is to determine the configuration of photovoltaic modules and photovoltaic array tracking mode, design photovoltaic array and layout scheme. But the project is a wading project, it is built in Dong Tan Lake polder I115, it needs scientific and reasonable evaluation to the effect of Dong Tan Lake’s flood storage and discharge. The results can provide guidance for similar engineering’s design.

Use of Flood Seasonality in Pooling-Group Formation and Quantile Estimation: An Application in Great Britain

NASA Astrophysics Data System (ADS)

Formetta, Giuseppe; Bell, Victoria; Stewart, Elizabeth

2018-02-01

Regional flood frequency analysis is one of the most commonly applied methods for estimating extreme flood events at ungauged sites or locations with short measurement records. It is based on: (i) the definition of a homogeneous group (pooling-group) of catchments, and on (ii) the use of the pooling-group data to estimate flood quantiles. Although many methods to define a pooling-group (pooling schemes, PS) are based on catchment physiographic similarity measures, in the last decade methods based on flood seasonality similarity have been contemplated. In this paper, two seasonality-based PS are proposed and tested both in terms of the homogeneity of the pooling-groups they generate and in terms of the accuracy in estimating extreme flood events. The method has been applied in 420 catchments in Great Britain (considered as both gauged and ungauged) and compared against the current Flood Estimation Handbook (FEH) PS. Results for gauged sites show that, compared to the current PS, the seasonality-based PS performs better both in terms of homogeneity of the pooling-group and in terms of the accuracy of flood quantile estimates. For ungauged locations, a national-scale hydrological model has been used for the first time to quantify flood seasonality. Results show that in 75% of the tested locations the seasonality-based PS provides an improvement in the accuracy of the flood quantile estimates. The remaining 25% were located in highly urbanized, groundwater-dependent catchments. The promising results support the aspiration that large-scale hydrological models complement traditional methods for estimating design floods.

Quantification of uncertainty in flood risk assessment for flood protection planning: a Bayesian approach

NASA Astrophysics Data System (ADS)

Dittes, Beatrice; Špačková, Olga; Ebrahimian, Negin; Kaiser, Maria; Rieger, Wolfgang; Disse, Markus; Straub, Daniel

2017-04-01

Flood risk estimates are subject to significant uncertainties, e.g. due to limited records of historic flood events, uncertainty in flood modeling, uncertain impact of climate change or uncertainty in the exposure and loss estimates. In traditional design of flood protection systems, these uncertainties are typically just accounted for implicitly, based on engineering judgment. In the AdaptRisk project, we develop a fully quantitative framework for planning of flood protection systems under current and future uncertainties using quantitative pre-posterior Bayesian decision analysis. In this contribution, we focus on the quantification of the uncertainties and study their relative influence on the flood risk estimate and on the planning of flood protection systems. The following uncertainty components are included using a Bayesian approach: 1) inherent and statistical (i.e. limited record length) uncertainty; 2) climate uncertainty that can be learned from an ensemble of GCM-RCM models; 3) estimates of climate uncertainty components not covered in 2), such as bias correction, incomplete ensemble, local specifics not captured by the GCM-RCM models; 4) uncertainty in the inundation modelling; 5) uncertainty in damage estimation. We also investigate how these uncertainties are possibly reduced in the future when new evidence - such as new climate models, observed extreme events, and socio-economic data - becomes available. Finally, we look into how this new evidence influences the risk assessment and effectivity of flood protection systems. We demonstrate our methodology for a pre-alpine catchment in southern Germany: the Mangfall catchment in Bavaria that includes the city of Rosenheim, which suffered significant losses during the 2013 flood event.

Evaluation of flood hazard maps in print and web mapping services as information tools in flood risk communication

NASA Astrophysics Data System (ADS)

Hagemeier-Klose, M.; Wagner, K.

2009-04-01

Flood risk communication with the general public and the population at risk is getting increasingly important for flood risk management, especially as a precautionary measure. This is also underlined by the EU Flood Directive. The flood related authorities therefore have to develop adjusted information tools which meet the demands of different user groups. This article presents the formative evaluation of flood hazard maps and web mapping services according to the specific requirements and needs of the general public using the dynamic-transactional approach as a theoretical framework. The evaluation was done by a mixture of different methods; an analysis of existing tools, a creative workshop with experts and laymen and an online survey. The currently existing flood hazard maps or web mapping services or web GIS still lack a good balance between simplicity and complexity with adequate readability and usability for the public. Well designed and associative maps (e.g. using blue colours for water depths) which can be compared with past local flood events and which can create empathy in viewers, can help to raise awareness, to heighten the activity and knowledge level or can lead to further information seeking. Concerning web mapping services, a linkage between general flood information like flood extents of different scenarios and corresponding water depths and real time information like gauge levels is an important demand by users. Gauge levels of these scenarios are easier to understand than the scientifically correct return periods or annualities. The recently developed Bavarian web mapping service tries to integrate these requirements.

Identifying Levee Breach Hotspots via Fine Resolution 2D Hydrodynamic Modeling - a Case Study in the Obion River

NASA Astrophysics Data System (ADS)

Bhuyian, M. N. M.; Kalyanapu, A. J.; Dullo, T. T.; VandenBerge, D.

2017-12-01

The Obion River, located in North-West Tennessee was channelized in last century to increase flow capacity and reduce flooding. Upstream of the river mainly consists of multiple tributaries that merge near Rives. The lowest water level (LWL) downstream of Rives has increased about four feet since 1980. It is estimated that this phenomenon could reduce 20% of channel conveyance if water surface slope is assumed same as channel slope. Reduction in conveyance would result in a frequent exposure to flood stage and higher stage for a given flood. Bed level change and exposure to flood stage are critical to levee safety. In the Obion River, levee breach was responsible for flooding in instances even when flood stage was lower than the levee crest. In such a circumstance, accurate simulation of inundation extent via conventional flood model is challenging because, the flood models consider ground data as static and cannot accommodate breaching unless the location of breaching is specified. Therefore, the objective of this study is to propose an approach for determining hotspots of levee breach via fine resolution hydrodynamic modeling to reduce uncertainty in flood inundation modeling. A two-dimensional LiDAR based hydrodynamic model for the Obion River would be used to determine levee breach hotspots using simulated flow parameters (i.e. current velocity, change in stage, time of exposure to high stage etc.) for a design flood event. Identifying breaching hotspots would allow determining probabilistic flood extent under probable breaching conditions. This should reduce uncertainty in inundation mapping in a channelized riverine system.

Extension of classical hydrological risk analysis to non-stationary conditions due to climate change - application to the Fulda catchment, Germany

NASA Astrophysics Data System (ADS)

Fink, G.; Koch, M.

2010-12-01

An important aspect in water resources and hydrological engineering is the assessment of hydrological risk, due to the occurrence of extreme events, e.g. droughts or floods. When dealing with the latter - as is the focus here - the classical methods of flood frequency analysis (FFA) are usually being used for the proper dimensioning of a hydraulic structure, for the purpose of bringing down the flood risk to an acceptable level. FFA is based on extreme value statistics theory. Despite the progress of methods in this scientific branch, the development, decision, and fitting of an appropriate distribution function stills remains a challenge, particularly, when certain underlying assumptions of the theory are not met in real applications. This is, for example, the case when the stationarity-condition for a random flood time series is not satisfied anymore, as could be the situation when long-term hydrological impacts of future climate change are to be considered. The objective here is to verify the applicability of classical (stationary) FFA to predicted flood time series in the Fulda catchment in central Germany, as they may occur in the wake of climate change during the 21st century. These discharge time series at the outlet of the Fulda basin have been simulated with a distributed hydrological model (SWAT) that is forced by predicted climate variables of a regional climate model for Germany (REMO). From the simulated future daily time series, annual maximum (extremes) values are computed and analyzed for the purpose of risk evaluation. Although the 21st century estimated extreme flood series of the Fulda river turn out to be only mildly non-stationary, alleviating the need for further action and concern at the first sight, the more detailed analysis of the risk, as quantified, for example, by the return period, shows non-negligent differences in the calculated risk levels. This could be verified by employing a new method, the so-called flood series maximum analysis (FSMA) method, which consists in the stochastic simulation of numerous trajectories of a stochastic process with a given GEV-distribution over a certain length of time (> larger than a desired return period). Then the maximum value for each trajectory is computed, all of which are then used to determine the empirical distribution of this maximum series. Through graphical inversion of this distribution function the size of the design flood for a given risk (quantile) and given life duration can be inferred. The results of numerous simulations show that for stationary flood series, the new FSMA method results, expectedly, in nearly identical risk values as the classical FFA approach. However, once the flood time series becomes slightly non-stationary - for reasons as discussed - and regardless of whether the trend is increasing or decreasing, large differences in the computed risk values for a given design flood occur. Or in other word, for the same risk, the new FSMA method would lead to different values in the design flood for a hydraulic structure than the classical FFA method. This, in turn, could lead to some cost savings in the realization of a hydraulic project.

Leveraging Trillions of Pixels for Flood Mitigation Decisions Support in the Rio Salado Basin, Argentina

NASA Astrophysics Data System (ADS)

Sullivan, J.; Routh, D.; Tellman, B.; Doyle, C.; Tomlin, J. N.

2017-12-01

The Rio Salado River Basin in Argentina is an economically important region that generates 25-30 percent of Argentina's grain and meat production. Between 2000-2011, floods in the basin caused nearly US$4.5 billion in losses and affected 5.5 million people. With the goal of developing cost-efficient flood monitoring and prediction capabilities in the Rio Salado Basin to support decision making, Cloud to Street is developing satellite based analytics to cover information gaps and improve monitoring capacity. This talk will showcase the Flood Risk Dashboard developed by Cloud to Street to support monitoring and decision-making at the level of provincial and national water management agencies in the Rio Salado Watershed. The Dashboard is based on analyzing thousands of MODIS, Landsat, and Sentinel scenes in Google Earth Engine to reconstruct the spatial history of flooding in the basin. The tool, iteratively designed with the end-user, shows a history of floodable areas with specific return times, exposed land uses and population, precipitation hyetographs, and spatial and temporal flood trends in the basin. These trends are used to understand both the impact of past flood mitigation investments (i.e. wetland reconstruction) and identify shifting flood risks. Based on this experience, we will also describe best practices on making remote sensing "flood dashboards" for water agencies.

Observed and forecast flood-inundation mapping application-A pilot study of an eleven-mile reach of the White River, Indianapolis, Indiana

USGS Publications Warehouse

Kim, Moon H.; Morlock, Scott E.; Arihood, Leslie D.; Kiesler, James L.

2011-01-01

Near-real-time and forecast flood-inundation mapping products resulted from a pilot study for an 11-mile reach of the White River in Indianapolis. The study was done by the U.S. Geological Survey (USGS), Indiana Silver Jackets hazard mitigation taskforce members, the National Weather Service (NWS), the Polis Center, and Indiana University, in cooperation with the City of Indianapolis, the Indianapolis Museum of Art, the Indiana Department of Homeland Security, and the Indiana Department of Natural Resources, Division of Water. The pilot project showed that it is technically feasible to create a flood-inundation map library by means of a two-dimensional hydraulic model, use a map from the library to quickly complete a moderately detailed local flood-loss estimate, and automatically run the hydraulic model during a flood event to provide the maps and flood-damage information through a Web graphical user interface. A library of static digital flood-inundation maps was created by means of a calibrated two-dimensional hydraulic model. Estimated water-surface elevations were developed for a range of river stages referenced to a USGS streamgage and NWS flood forecast point colocated within the study reach. These maps were made available through the Internet in several formats, including geographic information system, Keyhole Markup Language, and Portable Document Format. A flood-loss estimate was completed for part of the study reach by using one of the flood-inundation maps from the static library. The Federal Emergency Management Agency natural disaster-loss estimation program HAZUS-MH, in conjunction with local building information, was used to complete a level 2 analysis of flood-loss estimation. A Service-Oriented Architecture-based dynamic flood-inundation application was developed and was designed to start automatically during a flood, obtain near real-time and forecast data (from the colocated USGS streamgage and NWS flood forecast point within the study reach), run the two-dimensional hydraulic model, and produce flood-inundation maps. The application used local building data and depth-damage curves to estimate flood losses based on the maps, and it served inundation maps and flood-loss estimates through a Web-based graphical user interface.

A MODIS-based automated flood monitoring system for southeast asia

NASA Astrophysics Data System (ADS)

Ahamed, A.; Bolten, J. D.

2017-09-01

Flood disasters in Southeast Asia result in significant loss of life and economic damage. Remote sensing information systems designed to spatially and temporally monitor floods can help governments and international agencies formulate effective disaster response strategies during a flood and ultimately alleviate impacts to population, infrastructure, and agriculture. Recent destructive flood events in the Lower Mekong River Basin occurred in 2000, 2011, 2013, and 2016 (http://ffw.mrcmekong.org/historical_rec.htm, April 24, 2017). The large spatial distribution of flooded areas and lack of proper gauge data in the region makes accurate monitoring and assessment of impacts of floods difficult. Here, we discuss the utility of applying satellite-based Earth observations for improving flood inundation monitoring over the flood-prone Lower Mekong River Basin. We present a methodology for determining near real-time surface water extent associated with current and historic flood events by training surface water classifiers from 8-day, 250-m Moderate-resolution Imaging Spectroradiometer (MODIS) data spanning the length of the MODIS satellite record. The Normalized Difference Vegetation Index (NDVI) signature of permanent water bodies (MOD44W; Carroll et al., 2009) is used to train surface water classifiers which are applied to a time period of interest. From this, an operational nowcast flood detection component is produced using twice daily imagery acquired at 3-h latency which performs image compositing routines to minimize cloud cover. Case studies and accuracy assessments against radar-based observations for historic flood events are presented. The customizable system has been transferred to regional organizations and near real-time derived surface water products are made available through a web interface platform. Results highlight the potential of near real-time observation and impact assessment systems to serve as effective decision support tools for governments, international agencies, and disaster responders.

A prospective study of the impact of floods on the mental and physical health of older adults.

PubMed

Bei, Bei; Bryant, Christina; Gilson, Kim-Michelle; Koh, Juliana; Gibson, Penelope; Komiti, Angela; Jackson, Henry; Judd, Fiona

2013-01-01

With a longitudinal prospective design, we examined the impact of floods on the mental and physical health of older adults and explored risk and protective factors. Two hundred and seventy four older adults (age ≥60) completed surveys before and after a flood event. Both the surveys included measures of anxiety, depression, self-reported health, and satisfaction with life; the post-flood survey also included questionnaires on flood experience, symptoms of post-traumatic stress disorder (PTSD), stoicism, and psychological coping with floods. Compared to those not personally affected (78.8%), personally affected individuals (21.2%) reported significantly higher PTSD symptoms, with about one in six reporting PTSD symptoms that might require clinical attention. Personally affected individuals also reported a greater increase in anxiety post-flood, but changes in their depressive symptoms and self-reported health were not significantly different from those not personally affected. Greater flood exposure and the lack of social support were the risk factors for poorer mental and physical health. Higher stoicism was associated with higher post-flood depression and poorer self-reported mental health. The use of maladaptive coping, such as venting and distraction, was associated with greater deterioration in mental health after floods, whilst emotion-focused coping such as acceptance, positive reframing, and humour, was protective against such deterioration. Floods had adverse psychological impacts on some older adults who were personally affected. Despite the evidence of resilience, a small proportion of older adults experienced significant difficulties after the floods. The findings in this study help understand older adults' psychological responses to disasters and have practical implications for service planning and delivery.

Flood Seasonality in a Changing Climate - A Comparison Between Northern Europe and Northeastern North America

NASA Astrophysics Data System (ADS)

Matti, B.; Dahlke, H. E.; Dieppois, B.; Lawler, D.; Lyon, S. W.

2016-12-01

Fluvial flood events have a large impact on humans, both socially and economically. Concurrent with climate change flood seasonality in cold environments is expected to shift from a snowmelt-dominated to a rainfall-dominated flow regime. This would have profound impacts on water management strategies, i.e. flood risk mitigation, drinking water supply and hydro power. In addition, cold climate hydrological systems exhibit complex interactions with catchment properties and large-scale climate fluctuations making the manifestation of changes difficult to detect and predict. Understanding a possible change in flood seasonality is essential to mitigate risk and to keep management strategies viable under a changing climate. This study explored changes in flood seasonality across near-natural catchments in cold environments of the North Atlantic region (40 - 70° N) using circular statistics and trend tests. Results indicate strong seasonality in flooding for snowmelt-dominated catchments with a single peak occurring in spring (March through May), whereas flood peaks are more equally distributed throughout the year for catchments located close to the Atlantic coast and in the south of the study area. Flood seasonality has changed over the past century seen as decreasing trends in summer maximum daily flows and increasing winter and spring maximum daily flows. Mean daily flows corroborate those findings with approximately 50% of the catchments showing significant changes. Comparing Scandinavia to North America the same trends could be detected with a stronger signal at the west coast of Scandinavia due to the Westerlies. Contrasting trends were detected for spring flows, for which North American catchments showed decreasing trends whereas increasing trends were observed across Scandinavia. Such changes in flood seasonality have clear implications for management strategies such as the estimation of design floods for flood prevention measures.

Impacts of flood on health: epidemiologic evidence from Hanoi, Vietnam

PubMed Central

Bich, Tran Huu; Quang, La Ngoc; Thanh Ha, Le Thi; Duc Hanh, Tran Thi; Guha-Sapir, Debarati

2011-01-01

Background Vietnam is one of the most disaster-prone countries in the world. The country suffers from many kinds of natural disasters, of which the most common and serious one is flooding. Long and heavy rainfall during the last days of October and the first week of November 2008 resulted in a devastating flood unseen for over three decades in the capital city of Hanoi. It caused a substantial health impact on residents in and around the city and compromised the capacity of local health services. Objective The aim of this study is to ascertain the vulnerability and health impacts of the devastating flood in Hanoi by identifying the differences in mortality, injuries, and morbidity patterns (dengue, pink eye, dermatitis, psychological problems, and hypertension) between flood affected and non-affected households. Design A cross-sectional study was carried out involving 871 households in four selected communes (two heavily flood affected and two comparatively less affected) from two severely flooded districts of Hanoi. Participants were interviewed and information collected on the social, economic, and health impacts of the devastation within 1 month after the flood. Results The self-reported number of deaths and injuries reported in this study within 1 month after the heavy rainfall were a bit higher in severely affected communes as compared to that of the less affected communes of our study. The findings showed higher incidences of dengue fever, pink eye, dermatitis, and psychological problems in communes severely affected by flood as compared to that of the controlled communes. Conclusions For people in flood prone areas (at risk for flooding), flood prevention and mitigation strategies need to be seriously thought through and acted upon, as these people are exposed to greater health problems such as psychological issues and communicable diseases such as pink eye or dermatitis. PMID:21866222

An Overview of the Iowa Flood Forecasting and Monitoring System

NASA Astrophysics Data System (ADS)

Krajewski, W. F.

2016-12-01

Following the 2008 flood that devastated eastern Iowa the state legislators established the Iowa Flood Center at the University of Iowa with the mission of translational research towards flood mitigation. The Center has adavanced several components towards this goal. In particular, the Center has developed (1) state-wide flood inundation maps based on airborne lidar-based topography data and hydraulic models; (2) a network of nearly 250 real-time ultrasonic river stage sensors; (3) a detailed rainfall-runoff model for real time streamflow forecasting; and (4) cyberinfrastructure to acquire and manage data that includes High Performance Computing and browser-based information system designed for use by general public. The author discusses these components, their operational performance and their potential to assist in development of similar nation-wide systems. Specifically, many developments taking place at the National Water Center can benefit from the Iowa system serving as a reference.

SIMULATION OF FLOOD HYDROGRAPHS FOR GEORGIA STREAMS.

USGS Publications Warehouse

Inman, E.J.; Armbruster, J.T.

1986-01-01

Flood hydrographs are needed for the design of many highway drainage structures and embankments. A method for simulating these flood hydrographs at urban and rural ungauged sites in Georgia is presented. The O'Donnell method was used to compute unit hydrographs from 355 flood events from 80 stations. An average unit hydrograph and an average lag time were computed for each station. These average unit hydrographs were transformed to unit hydrographs having durations of one-fourth, one-third, one-half, and three-fourths lag time and then reduced to dimensionless terms by dividing the time by lag time and the discharge by peak discharge. Hydrographs were simulated for these 355 flood events and their widths were compared with the widths of the observed hydrographs at 50 and 75 percent of peak flow. For simulating hydrographs at sites larger than 500 mi**2, the U. S. Geological Survey computer model CONROUT can be used.

Analysis and Comparison on the Flood Simulation in Typical Hilly & Semi-mountainous Region

NASA Astrophysics Data System (ADS)

Luan, Qinghua; Wang, Dong; Zhang, Xiang; Liu, Jiahong; Fu, Xiaoran; Zhang, Kun; Ma, Jun

2017-12-01

Water-logging and flood are both serious in hilly and semi-mountainous cities of China, but the related research is rare. Lincheng Economic Development Zone (EDZ) in Hebei Province as the typical city was selected and storm water management model (SWMM) was applied for flood simulation in this study. The regional model was constructed through calibrating and verifying the runoff coefficient of different flood processes. Different designed runoff processes in five-year, ten-year and twenty-year return periods in basic scenario and in the low impact development (LID) scenario, respectively, were simulated and compared. The result shows that: LID measures have effect on peak reduction in the study area, but the effectiveness is not significant; the effectiveness of lagging peak time is poor. These simulation results provide decision support for the rational construction of LID in the study area, and provide the references for regional rain flood management.

Preparation of a flood-risk environmental index: case study of eight townships in Changhua County, Taiwan.

PubMed

Peng, Szu-Hsien

2018-02-26

To evaluate flood-prone areas, correlation analysis of flooding factors for the quantitative evaluation of hazard degree was determined to assist in further disaster prevention management. This study used flood-prone areas in 35 villages over eight townships (Changhua, Huatan, Yuanlin, Xiushui, Puyan, Hemei, Dacun, and Erlin) in Changhua County as research samples. Linear combination was used to evaluate flood-prone environmental indices, and an expert questionnaire was designed by using the analytic hierarchy process and the Delphi method to determine the weights of factors. These factors were then used to calculate the eigenvector of a pairwise comparison matrix to obtain the weights for the risk assessment criteria. Through collection of disaster cases, with particular focus on specifically protected areas where flooding has occurred or is likely to occur, public adaptation and response capabilities were evaluated by using an interview questionnaire that contains the items of perceived disaster risk, resource acquisition capability, adaptation capability, and environment understanding and disaster prevention education. Overlays in a geographic information system were used to analyze the flood-risk degree in villages and to construct a distribution map that contains flood-prone environment indices. The results can assist local governments in understanding the risk degree of various administrative areas to aid them in developing effective mitigation plans.

Flash floods in the Tatra Mountain streams: frequency and triggers.

PubMed

Ballesteros-Cánovas, J A; Czajka, B; Janecka, K; Lempa, M; Kaczka, R J; Stoffel, M

2015-04-01

Flash floods represent a frequently recurring natural phenomenon in the Tatra Mountains. On the northern slopes of the mountain chain, located in Poland, ongoing and expected future changes in climate are thought to further increase the adverse impacts of flash floods. Despite the repeat occurrence of major floods in the densely populated foothills of the Polish Tatras, the headwaters have been characterized by a surprising lack of data, such that any analysis of process variability or hydrometeorological triggers has been largely hampered so far. In this study, dendrogeomorphic techniques have been employed in four poorly-gauged torrential streams of the northern slope of the Tatra Mountains to reconstruct temporal and spatial patterns of past events. Using more than 1100 increment cores of trees injured by past flash floods, we reconstruct 47 events covering the last 148 years and discuss synoptic situations leading to the triggering of flash floods with the existing meteorological and flow gauge data. Tree-ring analyses have allowed highlighting the seasonality of events, providing new insights about potential hydrometeorological triggers as well as a differentiating flash flood activity between catchments. Results of this study could be useful to design future strategies to deal with flash flood risks at the foothills of the Polish Tatras and in the Vistula River catchment. Copyright © 2014. Published by Elsevier B.V.

Flooding and emergency room visits for gastrointestinal illness in Massachusetts: a case-crossover study.

PubMed

Wade, Timothy J; Lin, Cynthia J; Jagai, Jyotsna S; Hilborn, Elizabeth D

2014-01-01

Floods and other severe weather events are anticipated to increase as a result of global climate change. Floods can lead to outbreaks of gastroenteritis and other infectious diseases due to disruption of sewage and water infrastructure and impacts on sanitation and hygiene. Floods have also been indirectly associated with outbreaks through population displacement and crowding. We conducted a case-crossover study to investigate the association between flooding and emergency room visits for gastrointestinal illness (ER-GI) in Massachusetts for the years 2003 through 2007. We obtained ER-GI visits from the State of Massachusetts and records of floods from the National Oceanic and Atmospheric Association's Storm Events Database. ER-GI visits were considered exposed if a flood occurred in the town of residence within three hazard periods of the visit: 0-4 days; 5-9 days; and 10-14 days. A time-stratified bi-directional design was used for control selection, matching on day of the week with two weeks lead or lag time from the ER-GI visit. Fixed effect logistic regression models were used to estimate the risk of ER-GI visits following the flood. A total of 270,457 ER-GI visits and 129 floods occurred in Massachusetts over the study period. Across all counties, flooding was associated with an increased risk for ER-GI in the 0-4 day period after flooding (Odds Ratio: 1.08; 95% Confidence Interval: 1.03-1.12); but not the 5-9 days (Odds Ratio: 0.995; 95% Confidence Interval: 0.955-1.04) or the 10-14 days after (Odds Ratio: 0.966, 95% Confidence Interval: 0.927-1.01). Similar results were observed for different definitions of ER-GI. The effect differed across counties, suggesting local differences in the risk and impact of flooding. Statewide, across the study period, an estimated 7% of ER-GI visits in the 0-4 days after a flood event were attributable to flooding.

Adige river in Trento flooding map, 1892: private or public risk transfer?

NASA Astrophysics Data System (ADS)

Ranzi, Roberto

2016-04-01

For the determination of the flood risk hydrologist and hydraulic engineers focuse their attention mainly to the estimation of physical factors determining the flood hazard, while economists and experts of social sciences deal mainly with the estimation of vulnerability and exposure. The fact that flood zoning involves both hydrological and socio-economic aspects, however, was clear already in the XIX century when the impact of floods on inundated areas started to appear in flood maps, for instance in the UK and in Italy. A pioneering 'flood risk' map for the Adige river in Trento, Italy, was already published in 1892, taking into account in detail both hazard intensity in terms of velocity and depth, frequency of occurrence, vulnerability and economic costs for flood protection with river embankments. This map is likely to be the reinterpreted certainly as a pioneering, and possibly as the first flood risk map for an Italian river and worldwide. Risk levels were divided in three categories and seven sub-categories, depending on flood water depth, velocity, frequency and damage costs. It is interesting to notice the fact that at that time the map was used to share the cost of levees' reparation and enhancement after the severe September 1882 flood as a function of the estimated level of protection of the respective areas against the flood risk. The sharing of costs between public bodies, the railway company and private owners was debated for about 20 years and at the end the public sustained the major costs. This shows how already at that time the economic assessment of structural flood protections was based on objective and rational cost-benefit criteria, that hydraulic risk mapping was perceived by the society as fundamental for the design of flood protection systems and that a balanced cost sharing between public and private was an accepted approach although some protests arose at that time.

Application of flood-intensity-duration curve, rainfall-intensity-duration curve and time of concentration to analyze the pattern of storms and their corresponding floods for the natural flood events

NASA Astrophysics Data System (ADS)

Kim, Nam Won; Shin, Mun-Ju; Lee, Jeong Eun

2016-04-01

The analysis of storm effects on floods is essential step for designing hydraulic structure and flood plain. There are previous studies for analyzing the relationship between the storm patterns and peak flow, flood volume and durations for various sizes of the catchments, but they are not enough to analyze the natural storm effects on flood responses quantitatively. This study suggests a novel method of quantitative analysis using unique factors extracted from the time series of storms and floods to investigate the relationship between natural storms and their corresponding flood responses. We used a distributed rainfall-runoff model of Grid based Rainfall-runoff Model (GRM) to generate the simulated flow and areal rainfall for 50 catchments in Republic of Korea size from 5.6 km2 to 1584.2 km2, which are including overlapped dependent catchments and non-overlapped independent catchments. The parameters of the GRM model were calibrated to get the good model performances of Nash-Sutcliffe efficiency. Then Flood-Intensity-Duration Curve (FIDC) and Rainfall-Intensity-Duration Curve (RIDC) were generated by Flood-Duration-Frequency and Intensity-Duration-Frequency methods respectively using the time series of hydrographs and hyetographs. Time of concentration developed for the Korea catchments was used as a consistent measure to extract the unique factors from the FIDC and RIDC over the different size of catchments. These unique factors for the storms and floods were analyzed against the different size of catchments to investigate the natural storm effects on floods. This method can be easily used to get the intuition of the natural storm effects with various patterns on flood responses. Acknowledgement This research was supported by a grant (11-TI-C06) from Advanced Water Management Research Program funded by Ministry of Land, Infrastructure and Transport of Korean government.

Introduction to SNPP/VIIRS Flood Mapping Software Version 1.0

NASA Astrophysics Data System (ADS)

Li, S.; Sun, D.; Goldberg, M.; Sjoberg, W.; Santek, D.; Hoffman, J.

2017-12-01

Near real-time satellite-derived flood maps are invaluable to river forecasters and decision-makers for disaster monitoring and relief efforts. With support from the JPSS (Joint Polar Satellite System) Proving Ground and Risk Reduction (PGRR) Program, flood detection software has been developed using Suomi-NPP/VIIRS (Suomi National Polar-orbiting Partnership/Visible Infrared Imaging Radiometer Suite) imagery to automatically generate near real-time flood maps for National Weather Service (NWS) River Forecast Centers (RFC) in the USA. The software, which is called VIIRS NOAA GMU Flood Version 1.0 (hereafter referred to as VNG Flood V1.0), consists of a series of algorithms that include water detection, cloud shadow removal, terrain shadow removal, minor flood detection, water fraction retrieval, and floodwater determination. The software is designed for flood detection in any land region between 80°S and 80°N, and it has been running routinely with direct broadcast SNPP/VIIRS data at the Space Science and Engineering Center at the University of Wisconsin-Madison (UW/SSEC) and the Geographic Information Network of Alaska at the University of Alaska-Fairbanks (UAF/GINA) since 2014. Near real-time flood maps are distributed via the Unidata Local Data Manager (LDM), reviewed by river forecasters in AWIPS-II (the second generation of the Advanced Weather Interactive Processing System) and applied in flood operations. Initial feedback from operational forecasters on the product accuracy and performance has been largely positive. The software capability has also been extended to areas outside of the USA via a case-driven mode to detect major floods all over the world. Offline validation efforts include the visual inspection of over 10,000 VIIRS false-color composite images, an inter-comparison with MODIS automatic flood products and a quantitative evaluation using Landsat imagery. The steady performance from the 3-year routine process and the promising validation results indicate that VNG Flood V1.0 has a high feasibility for flood detection at the product level.

On the suitability of the copula types for the joint modelling of flood peaks and volumes along the Danube River

NASA Astrophysics Data System (ADS)

Kohnová, Silvia; Papaioannou, George; Bacigál, Tomáš; Szolgay, Ján; Hlavčová, Kamila; Loukas, Athanasios; Výleta, Roman

2017-04-01

Flood frequency analysis is often performed as a univariate analysis of flood peaks using a suitable theoretical probability distribution of the annual maximum flood peaks or peak over threshold values. However, also other flood attributes, such as flood volume and duration, are often necessary for the design of hydrotechnical structures and projects. In this study, the suitability of various copula families for a bivariate analysis of peak discharges and flood volumes has been tested on the streamflow data from gauging stations along the whole Danube River. Kendall's rank correlation coefficient (tau) quantifies the dependence between flood peak discharge and flood volume settings. The methodology is tested on two different data samples: 1) annual maximum flood (AMF) peaks with corresponding flood volumes, which is a typical choice for engineering studies and 2). annual maximum flood (AMF) peaks combined with annual maximum flow volumes of fixed durations at 5, 10, 15, 20, 25, 30 and 60 days, which can be regarded as a regime analysis of the dependence between the extremes of both variables in a given year. The bivariate modelling of the peak discharge - flood volume couples is achieved with the use of the the following copulas: Ali-Mikhail-Haq (AMH), Clayton, Frank, Joe, Gumbel, HuslerReiss, Galambos, Tawn, Normal, Plackett and FGM, respectively. Scatterplots of the observed and simulated peak discharge - flood volume pairs and goodness-of-fit tests have been used to assess the overall applicability of the copulas as well as observing any changes in suitable models along the Danube River. The results indicate that, almost all of the considered Archimedean class copulas (e.g. Frank, Clayton and Ali-Mikhail-Haq) perform better than the other copula families selected for this study, and that for the second data samples mostly the upper-tail-flat copulas were suitable.

Next generation paradigm for urban pluvial flood modelling, prediction, management and vulnerability reduction - Interaction between RainGain and Blue Green Dream projects

NASA Astrophysics Data System (ADS)

Maksimovic, C.

2012-04-01

The effects of climate change and increasing urbanisation call for a new paradigm for efficient planning, management and retrofitting of urban developments to increase resilience to climate change and to maximize ecosystem services. Improved management of urban floods from all sources in required. Time scale for well documented fluvial and coastal floods allows for timely response but surface (pluvial) flooding caused by intense local storms had not been given appropriate attention, Pitt Review (UK). Urban surface floods predictions require fine scale data and model resolutions. They have to be tackled locally by combining central inputs (meteorological services) with the efforts of the local entities. Although significant breakthrough in modelling of pluvial flooding was made there is a need to further enhance short term prediction of both rainfall and surface flooding. These issues are dealt with in the EU Iterreg project Rain Gain (RG). Breakthrough in urban flood mitigation can only be achieved by combined effects of advanced planning design, construction and management of urban water (blue) assets in interaction with urban vegetated areas' (green) assets. Changes in design and operation of blue and green assets, currently operating as two separate systems, is urgently required. Gaps in knowledge and technology will be introduced by EIT's Climate-KIC Blue Green Dream (BGD) project. The RG and BGD projects provide synergy of the "decoupled" blue and green systems to enhance multiple benefits to: urban amenity, flood management, heat island, biodiversity, resilience to drought thus energy requirements, thus increased quality of urban life at lower costs. Urban pluvial flood management will address two priority areas: Short Term rainfall Forecast and Short term flood surface forecast. Spatial resolution of short term rainfall forecast below 0.5 km2 and lead time of a few hours are needed. Improvements are achievable by combining data sources of raingauge networks with C-Band and X-Band radars with NWP and pluvial flood prediction models. The RG project deals with the merging and providing synergy of these technologies. Combined effects of BG technologies can totally reduce the risk of surface flooding for low return period events and up to 50-80% for high return periods. Demonstration technology testing sites for both BGD and RG projects will be established in 5 participating countries. Decision Support Systems will enhance full scale implementation of both BGD and RG project deliverables. A BGD efficiency rating scheme and training guidelines and e-learning tools will be developed. Experimental/demo sites for BDG and RG technology development and testing in Rotterdam, Paris, Berlin, Leuven and London and the expected results with concepts of RG and BGD projects and the initial results will be presented in the paper.

Summary of U.S. Geological Survey reports documenting flood profiles of streams in Iowa, 1963-2012

USGS Publications Warehouse

Eash, David A.

2014-01-01

This report is part of an ongoing program that is publishing flood profiles of streams in Iowa. The program is managed by the U.S. Geological Survey in cooperation with the Iowa Department of Transportation and the Iowa Highway Research Board (Project HR-140). Information from flood profiles is used by engineers to analyze and design bridges, culverts, and roadways. This report summarizes 47 U.S. Geological Survey flood-profile reports that were published for streams in Iowa during a 50-year period from 1963 to 2012. Flood events profiled in the reports range from 1903 to 2010. Streams in Iowa that have been selected for the preparation of flood-profile reports typically have drainage areas of 100 square miles or greater, and the documented flood events have annual exceedance probabilities of less than 2 to 4 percent. This report summarizes flood-profile measurements, changes in flood-profile report content throughout the years, streams that were profiled in the reports, the occurrence of flood events profiled, and annual exceedance-probability estimates of observed flood events. To develop flood profiles for selected flood events for selected stream reaches, the U.S. Geological Survey measured high-water marks and river miles at selected locations. A total of 94 stream reaches have been profiled in U.S. Geological Survey flood-profile reports. Three rivers in Iowa have been profiled along the same stream reach for five different flood events and six rivers in Iowa have been profiled along the same stream reach for four different flood events. Floods were profiled for June flood events for 18 different years, followed by July flood events for 13 years, May flood events for 11 years, and April flood events for 9 years. Most of the flood-profile reports include estimates of annual exceedance probabilities of observed flood events at streamgages located along profiled stream reaches. Comparisons of 179 historic and updated annual exceedance-probability estimates indicate few differences that are considered substantial between the historic and updated estimates for the observed flood events. Overall, precise comparisons for 114 observed flood events indicate that updated annual exceedance probabilities have increased for most of the observed flood events compared to the historic annual exceedance probabilities. Multiple large flood events exceeding the 2-percent annual exceedance-probability discharge estimate occurred at 37 of 98 selected streamgages during 1960–2012. Five large flood events were recorded at two streamgages in Ames during 1990–2010 and four large flood events were recorded at four other streamgages during 1973–2010. Results of Kendall’s tau trend-analysis tests for 35 of 37 selected streamgages indicate that a statistically significant trend is not evident for the 1963–2012 period of record; nor is an overall clear positive or negative trend evident for the 37 streamgages.

Soil Redox Dynamics Vary with Landscape Position and Hydroperiod in the Pantanal Wetland Ecosystem

NASA Astrophysics Data System (ADS)

Couto, E. G.; Johnson, M. S.; Pinto-jr, O.; Leite, N. K.

2012-12-01

The Pantanal wetland ecosystem of central South America is the largest tropical wetland complex in the world. Nevertheless, biogeochemistry in the Pantanal is quite limited. A unimodal precipitation regime averages approximately 1200 mm y-1 during the six-month rainy season, leading to seasonal flooding on much, but not all, of the landscape. We investigated the impact of landscape position and hydroperiod on soil redox potential (Eh) in four research locations in the Northern Pantanal near Poconé, Mato Grosso: two locations subject to flooding (a flooded forest and a flooded scrub forest) and two locations with infrequent surface flooding (tree islands known as cordilheiras). Redox sensors were installed at 10 cm and 30 cm depths at each of the four locations with half-hourly data recorded over all hydro-periods (dry season, rising water, flood and falling water). Here we summarize results to date in this ongoing study. Reducing conditions were observed in response to both precipitation events saturating soil from the surface downward, as well as in response to regional flooding dynamics that saturate soil from below. These are helping to guide design of a study on methane dynamics in the Pantanal wetland complex.

Methodology and Implications of Maximum Paleodischarge Estimates for

USGS Publications Warehouse

Channels, M.; Pruess, J.; Wohl, E.E.; Jarrett, R.D.

1998-01-01

Historical and geologic records may be used to enhance magnitude estimates for extreme floods along mountain channels, as demonstrated in this study from the San Juan Mountains of Colorado. Historical photographs and local newspaper accounts from the October 1911 flood indicate the likely extent of flooding and damage. A checklist designed to organize and numerically score evidence of flooding was used in 15 field reconnaissance surveys in the upper Animas River valley of southwestern Colorado. Step-backwater flow modeling estimated the discharges necessary to create longitudinal flood bars observed at 6 additional field sites. According to these analyses, maximum unit discharge peaks at approximately 1.3 m3 s~' km"2 around 2200 m elevation, with decreased unit discharges at both higher and lower elevations. These results (1) are consistent with Jarrett's (1987, 1990, 1993) maximum 2300-m elevation limit for flash-flooding in the Colorado Rocky Mountains, and (2) suggest that current Probable Maximum Flood (PMF) estimates based on a 24-h rainfall of 30 cm at elevations above 2700 m are unrealistically large. The methodology used for this study should be readily applicable to other mountain regions where systematic streamflow records are of short duration or nonexistent. ?? 1998 Regents of the University of Colorado.

Regional L-Moment-Based Flood Frequency Analysis in the Upper Vistula River Basin, Poland

NASA Astrophysics Data System (ADS)

Rutkowska, A.; Żelazny, M.; Kohnová, S.; Łyp, M.; Banasik, K.

2017-02-01

The Upper Vistula River basin was divided into pooling groups with similar dimensionless frequency distributions of annual maximum river discharge. The cluster analysis and the Hosking and Wallis (HW) L-moment-based method were used to divide the set of 52 mid-sized catchments into disjoint clusters with similar morphometric, land use, and rainfall variables, and to test the homogeneity within clusters. Finally, three and four pooling groups were obtained alternatively. Two methods for identification of the regional distribution function were used, the HW method and the method of Kjeldsen and Prosdocimi based on a bivariate extension of the HW measure. Subsequently, the flood quantile estimates were calculated using the index flood method. The ordinary least squares (OLS) and the generalised least squares (GLS) regression techniques were used to relate the index flood to catchment characteristics. Predictive performance of the regression scheme for the southern part of the Upper Vistula River basin was improved by using GLS instead of OLS. The results of the study can be recommended for the estimation of flood quantiles at ungauged sites, in flood risk mapping applications, and in engineering hydrology to help design flood protection structures.

Quantification of Uncertainty in the Flood Frequency Analysis

NASA Astrophysics Data System (ADS)

Kasiapillai Sudalaimuthu, K.; He, J.; Swami, D.

2017-12-01

Flood frequency analysis (FFA) is usually carried out for planning and designing of water resources and hydraulic structures. Owing to the existence of variability in sample representation, selection of distribution and estimation of distribution parameters, the estimation of flood quantile has been always uncertain. Hence, suitable approaches must be developed to quantify the uncertainty in the form of prediction interval as an alternate to deterministic approach. The developed framework in the present study to include uncertainty in the FFA discusses a multi-objective optimization approach to construct the prediction interval using ensemble of flood quantile. Through this approach, an optimal variability of distribution parameters is identified to carry out FFA. To demonstrate the proposed approach, annual maximum flow data from two gauge stations (Bow river at Calgary and Banff, Canada) are used. The major focus of the present study was to evaluate the changes in magnitude of flood quantiles due to the recent extreme flood event occurred during the year 2013. In addition, the efficacy of the proposed method was further verified using standard bootstrap based sampling approaches and found that the proposed method is reliable in modeling extreme floods as compared to the bootstrap methods.

Estimating flood magnitude and frequency for urban and small, rural streams in Georgia, South Carolina, and North Carolina, 2011

USGS Publications Warehouse

Feaster, Toby D.; Gotvald, Anthony J.; Weaver, J. Curtis

2014-01-01

Reliable estimates of the magnitude and frequency of floods are essential for the design of transportation and water-conveyance structures, flood insurance studies, and flood-plain management. Flood-frequency estimates are particularly important in densely populated urban areas. The U.S. Geological Survey (USGS) used a multistate approach to update methods for determining the magnitude and frequency of floods in urban and small, rural streams that are not substantially affected by regulation or tidal fluctuations in Georgia, South Carolina, and North Carolina (Feaster and others, 2014). The multistate approach has the advantage over a single state approach of increasing the number of streamflow-gaging station (streamgages) available for analysis, expanding the geographical coverage that would allow for application of regional regression equations across state boundaries, and building on a previous flood-frequency investigation of rural streamgages in the Southeastern United States. This investigation was funded as part of a cooperative program of water-resources investigations between the USGS, the South Carolina Department of Transportation, and the North Carolina Department of Transportation. In addition, much of the data and information for the Georgia streamgages was funded through a similar cooperative program with the Georgia Department of Transportation.

Evaluation of low impact development approach for mitigating flood inundation at a watershed scale in China.

PubMed

Hu, Maochuan; Sayama, Takahiro; Zhang, Xingqi; Tanaka, Kenji; Takara, Kaoru; Yang, Hong

2017-05-15

Low impact development (LID) has attracted growing attention as an important approach for urban flood mitigation. Most studies evaluating LID performance for mitigating floods focus on the changes of peak flow and runoff volume. This paper assessed the performance of LID practices for mitigating flood inundation hazards as retrofitting technologies in an urbanized watershed in Nanjing, China. The findings indicate that LID practices are effective for flood inundation mitigation at the watershed scale, and especially for reducing inundated areas with a high flood hazard risk. Various scenarios of LID implementation levels can reduce total inundated areas by 2%-17% and areas with a high flood hazard level by 6%-80%. Permeable pavement shows better performance than rainwater harvesting against mitigating urban waterlogging. The most efficient scenario is combined rainwater harvesting on rooftops with a cistern capacity of 78.5 mm and permeable pavement installed on 75% of non-busy roads and other impervious surfaces. Inundation modeling is an effective approach to obtaining the information necessary to guide decision-making for designing LID practices at watershed scales. Copyright © 2017 Elsevier Ltd. All rights reserved.

Using practical and social information to influence flood adaptation behavior

NASA Astrophysics Data System (ADS)

Allaire, Maura C.

2016-08-01

As the prospect for more frequent and severe extreme weather events gains scientific support, many nations are evaluating mitigation and adaptation options. Insurance and home retrofits could reduce household welfare losses due to flood events. Yet even after disasters, households often fail to take risk mitigation actions. This paper presents the first randomized field experiment that tests the effect of information provision on household uptake of flood insurance and home retrofits. A sample of 364 flood-prone households in Bangkok was randomly split into treatment and control groups. The treatment group received practical details on home retrofits and flood insurance as well as social information regarding the insurance purchase decisions of peers. Results indicate that the information intervention increased insurance purchases by about five percentage points, while no effect was detected for home retrofits. This effect is nearly equal to the increase in uptake that the national insurance program in Thailand has achieved through all other means since its establishment in 2012. If scaled up to include all uninsured, flood-prone households in Bangkok, nearly 70,000 additional households could be insured. The results suggest that well-designed information interventions could increase uptake of flood insurance, without additional premium subsidies or mandates.

Designing a Software for Flood Risk Assessment Based on Multi Criteria Desicion Analysis and Information Diffusion Methods

NASA Astrophysics Data System (ADS)

Musaoglu, N.; Saral, A.; Seker, D. Z.

2012-12-01

Flooding is one of the major natural disasters not only in Turkey but also in all over the world and it causes serious damage and harm. It is estimated that of the total economic loss caused by all kinds of disasters, 40% was due to floods. In July 1995, the Ayamama Creek in Istanbul was flooded, the insurance sector received around 1,200 claims notices during that period, insurance companies had to pay a total of $40 million for claims. In 2009, the same creek was flooded again and killed 31 people over two days and insurance firms paid for damages around cost €150 million for claims. To solve these kinds of problems modern tools such as GIS and Remote Sensing should be utilized. In this study, a software was designed for the flood risk analysis with Analytic Hierarchy Process (AHP) and Information Diffusion( InfoDif) methods.In the developed sofware, five evaluation criterias were taken into account, which were slope, aspect, elevation, geology and land use which were extracted from the satellite sensor data. The Digital Elevation Model (DEM) of the Ayamama River Basin was acquired from the SPOT 5 satellite image with 2.5 meter spatial resolution. Slope and aspect values of the study basin were extracted from this DEM. The land use of the Ayamama Creek was obtained by performing object-oriented nearest neighbor classification method by image segmentation on SPOT 5 image dated 2010. All produced data were used as an input for the part of Multi Criteria Desicion Analysis (MCDA) method of this software. Criterias and their each sub criteras were weighted and flood vulnerability was determined with MCDA-AHP. Also, daily flood data was collected from Florya Meteorological Station, between 1975 to 2009 years and the daily flood peak discharge was calculated with the method of Soil Conservation Service-Curve Number (SCS-CN) and were used as an input in the software for the part of InfoDif.Obtained results were verified using ground truth data and it has been clearly seen that the developed (TRA) software which uses two different methods for flood risk analysis, can be more effective for achieving different decision problems, from conventional techniques and produce more reliable results in a short time.; Study Area

44 CFR Appendix A(1) to Part 61 - Appendix A(1) to Part 61

Code of Federal Regulations, 2011 CFR

2011-10-01

... only: 1. A non-condominium residential building designed for principal use as a dwelling place of one... properties (one of which is your property) from: a. Overflow of inland or tidal waters, b. Unusual and rapid... premium payment must accompany the application. 4. Base Flood. A flood having a one percent chance of...

44 CFR Appendix A(1) to Part 61 - Appendix A(1) to Part 61

Code of Federal Regulations, 2013 CFR

2013-10-01

... only: 1. A non-condominium residential building designed for principal use as a dwelling place of one... properties (one of which is your property) from: a. Overflow of inland or tidal waters, b. Unusual and rapid... premium payment must accompany the application. 4. Base Flood. A flood having a one percent chance of...

44 CFR Appendix A(1) to Part 61 - Appendix A(1) to Part 61

Code of Federal Regulations, 2012 CFR

2012-10-01

... only: 1. A non-condominium residential building designed for principal use as a dwelling place of one... properties (one of which is your property) from: a. Overflow of inland or tidal waters, b. Unusual and rapid... premium payment must accompany the application. 4. Base Flood. A flood having a one percent chance of...

44 CFR Appendix A(1) to Part 61 - Appendix A(1) to Part 61

Code of Federal Regulations, 2010 CFR

2010-10-01

... only: 1. A non-condominium residential building designed for principal use as a dwelling place of one... properties (one of which is your property) from: a. Overflow of inland or tidal waters, b. Unusual and rapid... premium payment must accompany the application. 4. Base Flood. A flood having a one percent chance of...

44 CFR Appendix A(1) to Part 61 - Appendix A(1) to Part 61

Code of Federal Regulations, 2014 CFR

2014-10-01

... only: 1. A non-condominium residential building designed for principal use as a dwelling place of one... properties (one of which is your property) from: a. Overflow of inland or tidal waters, b. Unusual and rapid... premium payment must accompany the application. 4. Base Flood. A flood having a one percent chance of...

78 FR 20331 - Changes in Flood Hazard Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-04

... flood insurance premium rates for new buildings and the contents of those buildings. For rating purposes............ 350070 (12-06-1488P). David Coss, Avenue, Santa Fe, team.com/lomrs.htm. Mayor, City of NM 87501. Santa Fe... Design http://www.rampp- May 28, 2013......... 405381 06-1019P). Dewey F. Office, 2317 team.com/lomrs.htm...

Active water management at the cathode of a planar air-breathing polymer electrolyte membrane fuel cell using an electroosmotic pump

NASA Astrophysics Data System (ADS)

Fabian, T.; O'Hayre, R.; Litster, S.; Prinz, F. B.; Santiago, J. G.

In a typical air-breathing fuel cell design, ambient air is supplied to the cathode by natural convection and dry hydrogen is supplied to a dead-ended anode. While this design is simple and attractive for portable low-power applications, the difficulty in implementing effective and robust water management presents disadvantages. In particular, excessive flooding of the open-cathode during long-term operation can lead to a dramatic reduction of fuel cell power. To overcome this limitation, we report here on a novel air-breathing fuel cell water management design based on a hydrophilic and electrically conductive wick in conjunction with an electroosmotic (EO) pump that actively pumps water out of the wick. Transient experiments demonstrate the ability of the EO-pump to "resuscitate" the fuel cell from catastrophic flooding events, while longer term galvanostatic measurements suggest that the design can completely eliminate cathode flooding using less than 2% of fuel cell power, and lead to stable operation with higher net power performance than a control design without EO-pump. This demonstrates that active EO-pump water management, which has previously only been demonstrated in forced-convection fuel cell systems, can also be applied effectively to miniaturized (<5 W) air-breathing fuel cell systems.

Thirty Years Later: Reflections of the Big Thompson Flood, Colorado, 1976 to 2006

NASA Astrophysics Data System (ADS)

Jarrett, R. D.; Costa, J. E.; Brunstein, F. C.; Quesenberry, C. A.; Vandas, S. J.; Capesius, J. P.; O'Neill, G. B.

2006-12-01

Thirty years ago, over 300 mm of rain fell in about 4 to 6 hours in the middle reaches of the Big Thompson River Basin during the devastating flash flood on July 31, 1976. The rainstorm produced flood discharges that exceeded 40 m3/s/km2. A peak discharge of 883 m3/s was estimated at the Big Thompson River near Drake streamflow-gaging station. The raging waters left 144 people dead, 250 injured, and over 800 people were evacuated by helicopter. Four-hundred eighteen homes and businesses were destroyed, as well as 438 automobiles, and damage to infrastructure left the canyon reachable only via helicopter. Total damage was estimated in excess of $116 million (2006 dollars). Natural hazards similar to the Big Thompson flood are rare, but the probability of a similar event hitting the Front Range, other parts of Colorado, or other parts of the Nation is real. Although much smaller in scale than the Big Thompson flood, several flash floods have happened during the monsoon in early July 2006 in the Colorado foothills that reemphasized the hazards associated with flash flooding. The U.S. Geological Survey (USGS) conducts flood research to help understand and predict the magnitude and likelihood of large streamflow events such as the Big Thompson flood. A summary of hydrologic conditions of the 1976 flood, what the 1976 flood can teach us about flash floods, a description of some of the advances in USGS flood science as a consequence of this disaster, and lessons that we learned to help reduce loss of life from this extraordinary flash flood are discussed. In the 30 years since the Big Thompson flood, there have been important advances in streamflow monitoring and flood warning. The National Weather Service (NWS) NEXRAD radar allows real-time monitoring of precipitation in most places in the United States. The USGS currently (2006) operates about 7,250 real-time streamflow-gaging stations in the United States that are monitored by the USGS, the NWS, and emergency managers. When substantial flooding occurs, the USGS mobilizes personnel to collect streamflow data in affected areas. Streamflow data improve flood forecasting and provide data for flood-frequency analysis for floodplain management, design of structures located in floodplains, and related water studies. An important lesson learned is that nature provides environmental signs before and during floods that can help people avoid hazard areas. Important contributions to flood science as a result of the 1976 flood include development of paleoflood methods to interpret the preserved flood-plain stratigraphy to document the number, magnitude, and age of floods that occurred prior to streamflow monitoring. These methods and data on large floods can be used in many mountain-river systems to help us better understand flood hazards and plan for the future. For example, according to conventional flood-frequency analysis, the 1976 Big Thompson flood had a flood recurrence interval of about 100 years. However, paleoflood research indicated the 1976 flood was the largest in about the last 10,000 years in the basin and had a flood recurrence interval in excess of 1,000 years.

Integrated Modeling Approach for the Development of Climate-Informed, Actionable Information

DOE Office of Scientific and Technical Information (OSTI.GOV)

Judi, David R.; Rakowski, Cynthia L.; Waichler, Scott R.

Flooding is a prevalent natural disaster with both short and long-term social, economic, and infrastructure impacts. Changes in intensity and frequency of precipitation (including rain, snow, and rain on snow) events create challenges for the planning and management of resilient infrastructure and communities. While there is general acknowledgement that new infrastructure design should account for future climate change, no clear methods or actionable information is available to community planners and designers to ensure resilient design considering an uncertain climate future. This research used climate projections to drive high-resolution hydrology and flood models to evaluate social, economic, and infrastructure resilience formore » the Snohomish Watershed, WA, U.S.A. The proposed model chain has been calibrated and validated. Based on the established model chain, the peaks of precipitation and streamflows were found to shift from spring and summer to earlier winter season. The nonstationarity of peak discharges was discovered with more frequent and severe flood risks projected. The peak discharges were also projected to decrease for a certain period in the near future, which might be due to the reduced rain-on-snow events. This research was expected to provide a clear method for the incorporation of climate science in flood resilience analysis and to also provide actionable information relative to the frequency and intensity of future precipitation events.« less

On Flood Frequency in Urban Areas under Changing Conditions and Implications on Stormwater Infrastructure Planning and Design

NASA Astrophysics Data System (ADS)

Norouzi, A.; Habibi, H.; Nazari, B.; Noh, S.; Seo, D. J.; Zhang, Y.

2016-12-01

With urbanization and climate change, many areas in the US and abroad face increasing threats of flash flooding. Due to nonstationarities arising from changes in land cover and climate, however, it is not readily possible to project how such changes may modify flood frequency. In this work, we describe a simple spatial stochastic model for rainfall-to-areal runoff in urban areas, evaluate climatological mean and variance of mean areal runoff (MAR) over a range of catchment scale, translate them into runoff frequency, which is used as a proxy for flood frequency, and assess its sensitivity to precipitation, imperviousness and soil, and their changes as a function of catchment scale and magnitude of precipitation. The findings indicate that, due to large sensitivity of frequency of MAR to multiple hydrometeorological and physiographic factors, estimation of flood frequency for urban catchments is inherently more uncertain. The approach used in this work is useful in developing bounds for flood frequencies in urban areas under nonstationary conditions arising from urbanization and climate change.

An Approach to Assessing Flood Risk in Low-lying Paddy Areas of Japan considering Economic Damage on Rice

NASA Astrophysics Data System (ADS)

Minakawa, H.; Masumoto, T.

2013-12-01

Hiroki Minakawa, Takao Masumoto National Institute for Rural Engineering (NIRE), NARO, Japan Flooding is one type of nature disaster, and is caused by heavy rainfall events. In the future, the risk of flooding is predicted to increase due to global climate change. Immediate measures such as strengthening drainage capacity are needed to minimize the damage caused by more frequent flooding, so a quantitative evaluation method of flood risks is needed to discuss countermeasure against these problems. At the same time, rice is an important crop for food production in Japan. However, paddy fields are often damaged by flooding because they are principally spread in lower part of the basin. Therefore, it is also important to assess the damages to paddy fields. This study discusses a method for evaluating a relationship between the risk of flood damage and the scale of heavy rainfall. We also developed a method of estimating the economic effect of a reduction in rice yield by flooding. First, we developed a drainage analysis model that incorporates kinematic and diffusive runoff models for calculating water level in channels and paddies. Next, heavy rainfall data for drainage analyses were generated by using a diurnal rainfall pattern generator. The generator can create hourly data of heavy rainfall, and internal pattern of them is different each. These data were input to the drainage model to estimate flood risk. Simultaneously, we tried to clarify economic losses of a rice yields caused by flooding. Here, the reduction scale in rice yield which shows relations between flooding situation (e.g. water level, duration of submersion etc.) and damage of rice is available to calculate reduction of rice yield. In this study, we created new reduction scales through a pseudo-flooding experiment under real inundation conditions. The methodology of the experiment was as follow: We chose the popular Japanese rice cultivar Koshihikari for this experiment. An experimental arena was constructed in a rice paddy plot, which consisted of two zones, one in which the rice was cultivated as usual with normal water levels, and a flood zone, which was used for submerging rice plants. The flood zone, which was designed to reproduce actual flood disaster conditions in paddy fields, can be filled with water to a depth of 0.3, 0.6 or 0.9 m above ground level, and is divided into two plots, a clean water part and a turbid water part. Thus, the experimental conditions can vary according to 1) the development stage of rice, 2) complete or incomplete submersion, 3) clean or turbid water, and 4) duration of submergence. Finally, the reduction scales were formulated by using the resultant data and it was found that rice is most sensitive to damage during the development stage. Flood risk was evaluated by using calculated water level on each paddy. Here, the averaged duration of inundation to a depth of more than 0.3 m was used as the criteria for flood occurrence. The results indicated that the duration increased with larger heavy rainfall amounts. Furthermore, the damage to rice was predicted to increase especially in low-lying paddy fields. Mitigation measures, such as revising drainage planning and/or changing design standards for the capacity of drainage pumps may be necessary in the future.

Flood impacts on a water distribution network

NASA Astrophysics Data System (ADS)

Arrighi, Chiara; Tarani, Fabio; Vicario, Enrico; Castelli, Fabio

2017-12-01

Floods cause damage to people, buildings and infrastructures. Water distribution systems are particularly exposed, since water treatment plants are often located next to the rivers. Failure of the system leads to both direct losses, for instance damage to equipment and pipework contamination, and indirect impact, since it may lead to service disruption and thus affect populations far from the event through the functional dependencies of the network. In this work, we present an analysis of direct and indirect damages on a drinking water supply system, considering the hazard of riverine flooding as well as the exposure and vulnerability of active system components. The method is based on interweaving, through a semi-automated GIS procedure, a flood model and an EPANET-based pipe network model with a pressure-driven demand approach, which is needed when modelling water distribution networks in highly off-design conditions. Impact measures are defined and estimated so as to quantify service outage and potential pipe contamination. The method is applied to the water supply system of the city of Florence, Italy, serving approximately 380 000 inhabitants. The evaluation of flood impact on the water distribution network is carried out for different events with assigned recurrence intervals. Vulnerable elements exposed to the flood are identified and analysed in order to estimate their residual functionality and to simulate failure scenarios. Results show that in the worst failure scenario (no residual functionality of the lifting station and a 500-year flood), 420 km of pipework would require disinfection with an estimated cost of EUR 21 million, which is about 0.5 % of the direct flood losses evaluated for buildings and contents. Moreover, if flood impacts on the water distribution network are considered, the population affected by the flood is up to 3 times the population directly flooded.

Assessing the Utility of a Satellite-Based Flood Inundation and Socio-Economic Impact Tool for the Lower Mekong River Basin

NASA Astrophysics Data System (ADS)

Ahamed, A.; Bolten, J. D.

2016-12-01

Flood disaster events in Southeast Asia result in significant loss of life and economic damage. Remote sensing information systems designed to monitor floods and assess their severity can help governments and international agencies formulate an effective response before and during flood events, and ultimately alleviate impacts to population, infrastructure, and agriculture. Recent examples of destructive flood events in the Lower Mekong River Basin occurred in 2000, 2011, and 2013. Floods can be particularly costly in the developing countries of Southeast Asia where large portions of the population live on or near the floodplain (Jonkman, 2005; Kirsch et al., 2012; Long and Trong, 2001; Stromberg. 2007). Regional studies (Knox, 1993; Mirza, 2002; Schiermeier, 2011; Västilä et al, 2010) and Intergovernmental Panel on Climate Change (IPCC, 2007) projections suggest that precipitation extremes and flood frequency are increasing. Thus, improved systems to rapidly monitor flooding in vulnerable areas are needed. This study determines surface water extent for current and historic flood events by using stacks of historic multispectral Moderate-resolution Imaging Spectroradiometer (MODIS) 250-meter imagery and the spectral Normalized Difference Vegetation Index (NDVI) signatures of permanent water bodies (MOD44W). Supporting software tools automatically assess flood impacts to population and infrastructure to provide a rapid first set of impact numbers generated hours after the onset of an event. The near real-time component uses twice daily imagery acquired at 3-hour latency, and performs image compositing routines to minimize cloud cover. Case studies for historic flood events are presented. Results suggest that near real-time remote sensing-based observation and impact assessment systems can serve as effective regional decision support tools for governments, international agencies, and disaster responders.

The National Flood Frequency Program, version 3 : a computer program for estimating magnitude and frequency of floods for ungaged sites

USGS Publications Warehouse

Ries, Kernell G.; Crouse, Michele Y.

2002-01-01

For many years, the U.S. Geological Survey (USGS) has been developing regional regression equations for estimating flood magnitude and frequency at ungaged sites. These regression equations are used to transfer flood characteristics from gaged to ungaged sites through the use of watershed and climatic characteristics as explanatory or predictor variables. Generally, these equations have been developed on a Statewide or metropolitan-area basis as part of cooperative study programs with specific State Departments of Transportation. In 1994, the USGS released a computer program titled the National Flood Frequency Program (NFF), which compiled all the USGS available regression equations for estimating the magnitude and frequency of floods in the United States and Puerto Rico. NFF was developed in cooperation with the Federal Highway Administration and the Federal Emergency Management Agency. Since the initial release of NFF, the USGS has produced new equations for many areas of the Nation. A new version of NFF has been developed that incorporates these new equations and provides additional functionality and ease of use. NFF version 3 provides regression-equation estimates of flood-peak discharges for unregulated rural and urban watersheds, flood-frequency plots, and plots of typical flood hydrographs for selected recurrence intervals. The Program also provides weighting techniques to improve estimates of flood-peak discharges for gaging stations and ungaged sites. The information provided by NFF should be useful to engineers and hydrologists for planning and design applications. This report describes the flood-regionalization techniques used in NFF and provides guidance on the applicability and limitations of the techniques. The NFF software and the documentation for the regression equations included in NFF are available at http://water.usgs.gov/software/nff.html.

Living with floods - Household perception and satellite observations in the Barotse floodplain, Zambia

NASA Astrophysics Data System (ADS)

Cai, Xueliang; Haile, Alemseged Tamiru; Magidi, James; Mapedza, Everisto; Nhamo, Luxon

2017-08-01

The Barotse Floodplain, a designated Ramsar site, is home to thousands of indigenous people along with an extensive wetland ecosystem and food production system. Increasingly it is also a popular tourist destination with its annual Kuomboka festival which celebrates the relocation of the king and the Lozi people to higher ground before the onset of the flood season. This paper presents an integrated approach which cross validates and combines the floodplain residents' perceptions about recent floods with information on flood inundation levels derived from satellite observations. Local residents' surveys were conducted to assess farmers' perception on the flooding patterns and the impact on their livelihoods. Further, a series of flood inundation maps from 1989 to 2014 generated from remotely sensed Landsat imagery were used to assess the recent patterns of floods. Results show that the floodplain has a population of 33 thousand living in 10,849 small permeant or temporary buildings with a total cropland area of 4976 ha. The floodplain hydrology and flooding patterns have changed, confirmed by both surveys and satellite image analysis, due to catchment development and changing climate. The average annual inundated areas have increased from about 316 thousand ha in 1989-1998 to 488 thousand ha in 2005-2014. As a result the inundated cropland and houses increased from 9% to 6% in 1989 to 73% and 47% in 2014, respectively. The timing of the floods has also changed with both delaying and early onset happening more frequently. These changes cause increasing difficulties in flood forecast and preparation using indigenous knowledge, therefore creating greater damages to crops, livestock, and houses. Current floodplain management system is inadequate and new interventions are needed to help manage the floods at a systematic manner.

Use of Space Technology in Flood Mitigation (Western Province, Zambia)

NASA Astrophysics Data System (ADS)

Mulando, A.

2001-05-01

Disasters, by definition are events that appear suddenly and with little warning. They are usually short lived, with extreme events bringing death, injury and destruction of buildings and communications. Their aftermath can be as damaging as their physical effects through destruction of sanitation and water supplies, destruction of housing and breakdown of transport for food, temporary shelter and emergency services. Since floods are one of the natural disasters which endanger both life and property, it becomes vital to know its extents and where the hazards exists. Flood disasters manifest natural processes on a larger scale and information provided by Remote Sensing is a most appropriate input to analysis of actual events and investigations of potential risks. An analytical and qualitative image processing and interpretation of Remotely Sensed data as well as other data such as rainfall, population, settlements not to mention but a few should be used to derive good mitigation strategies. Since mitigation is the cornerstone of emergency management, it therefore becomes a sustained action that will reduce or eliminate long term risks to people and property from natural hazards such as floods and their effects. This will definitely involve keeping of homes and other sensitive structures away from flood plains. Promotion of sound land use planning based on this known hazard, "FLOODS" is one such form of mitigation that can be applied in flood affected areas within flood plain. Therefore future mitigation technologies and procedures should increasingly be based on the use of flood extent information provided by Remote Sensing Satellites like the NOAA AVHRR as well as information on the designated flood hazard and risk areas.

Recommendations for the user-specific enhancement of flood maps

NASA Astrophysics Data System (ADS)

Meyer, V.; Kuhlicke, C.; Luther, J.; Fuchs, S.; Priest, S.; Dorner, W.; Serrhini, K.; Pardoe, J.; McCarthy, S.; Seidel, J.; Palka, G.; Unnerstall, H.; Viavattene, C.; Scheuer, S.

2012-05-01

The European Union Floods Directive requires the establishment of flood maps for high risk areas in all European member states by 2013. However, the current practice of flood mapping in Europe still shows some deficits. Firstly, flood maps are frequently seen as an information tool rather than a communication tool. This means that, for example, local stocks of knowledge are not incorporated. Secondly, the contents of flood maps often do not match the requirements of the end-users. Finally, flood maps are often designed and visualised in a way that cannot be easily understood by residents at risk and/or that is not suitable for the respective needs of public authorities in risk and event management. The RISK MAP project examined how end-user participation in the mapping process may be used to overcome these barriers and enhance the communicative power of flood maps, fundamentally increasing their effectiveness. Based on empirical findings from a participatory approach that incorporated interviews, workshops and eye-tracking tests, conducted in five European case studies, this paper outlines recommendations for user-specific enhancements of flood maps. More specific, recommendations are given with regard to (1) appropriate stakeholder participation processes, which allow incorporating local knowledge and preferences, (2) the improvement of the contents of flood maps by considering user-specific needs and (3) the improvement of the visualisation of risk maps in order to produce user-friendly and understandable risk maps for the user groups concerned. Furthermore, "idealised" maps for different user groups are presented: for strategic planning, emergency management and the public.

Public responses to flood warning messages: the Floodline service in Scotland

NASA Astrophysics Data System (ADS)

Cranston, Michael; Geddes, Alistair; Black, Andrew; Ambler, Alice; Menmuir, Cordelia

2017-04-01

Over the past decade, efforts have been made to improve the national flood warning system in Scotland, with new capabilities in the underlying flood forecasting tools, as well as development of an active flood warning dissemination service. This paper focusses on the latter service, for which there are around 26,000 customers registered at present, and which saw over 300,000 individual messages being issued during recent floods in winter 2015/16. However, notwithstanding such promising signs of change, evidence of how (if at all) the flood warning messages disseminated by the service actually impacts on recipient behaviour remains more limited. For example, this includes knowledge of the extent to which the messages influence actions on flood preparedness and mitigation. In consequence, there are also ongoing questions over the cost-effectiveness of the service in its current format, and of its scalability to even larger numbers of recipients. This paper will present initial findings from the first detailed study of customer perceptions of the messages distributed via the Scottish flood warning system, officially known as Floodline. In particular, the primary focus will be on results generated from a web-based questionnaire survey of registered Floodline customers. The survey was designed to assess associations between multiple customer characteristics, including location and risk level, type of warning message received, prior experience of flooding, risk awareness, and demographics. The study was conducted for the Scottish Environment Protection Agency, which is responsible for running the Floodline service. More broadly it resonates with current emphases on exploring effective means of hazard communication and encouraging public engagement in flood risk management.

Upstream structural management measures for an urban area flooding in Turkey

NASA Astrophysics Data System (ADS)

Akyurek, Z.; Bozoğlu, B.; Sürer, S.; Mumcu, H.

2015-06-01

In recent years, flooding has become an increasing concern across many parts of the world of both the general public and their governments. The climate change inducing more intense rainfall events occurring in short period of time lead flooding in rural and urban areas. In this study the flood modelling in an urbanized area, namely Samsun-Terme in Blacksea region of Turkey is performed. MIKE21 with flexible grid is used in 2-dimensional shallow water flow modelling. 1 × 1000-1 scaled maps with the buildings for the urbanized area and 1 × 5000-1 scaled maps for the rural parts are used to obtain DTM needed in the flood modelling. The bathymetry of the river is obtained from additional surveys. The main river passing through the urbanized area has a capacity of 500 m3 s-1 according to the design discharge obtained by simple ungauged discharge estimation depending on catchment area only. The upstream structural base precautions against flooding are modelled. The effect of four main upstream catchments on the flooding in the downstream urban area are modelled as different scenarios. It is observed that if the flow from the upstream catchments can be retarded through a detention pond constructed in one of the upstream catchments, estimated Q100 flood can be conveyed by the river without overtopping from the river channel. The operation of the upstream detention ponds and the scenarios to convey Q500 without causing flooding are also presented. Structural management measures to address changes in flood characteristics in water management planning are discussed.

Using Minimax Regret Optimization to Search for Multi-Stakeholder Solutions to Deeply Uncertain Flood Hazards under Climate Change

NASA Astrophysics Data System (ADS)

Kirshen, P. H.; Hecht, J. S.; Vogel, R. M.

2015-12-01

Prescribing long-term urban floodplain management plans under the deep uncertainty of climate change is a challenging endeavor. To address this, we have implemented and tested with stakeholders a parsimonious multi-stage mixed integer programming (MIP) model that identifies the optimal time period(s) for implementing publicly and privately financed adaptation measures. Publicly funded measures include reach-scale flood barriers, flood insurance, and buyout programs to encourage property owners in flood-prone areas to retreat from the floodplain. Measures privately funded by property owners consist of property-scale floodproofing options, such as raising building foundations, as well as investments in flood insurance or retreat from flood-prone areas. The objective function to minimize the sum of flood control and damage costs in all planning stages for different property types during floods of different severities. There are constraints over time for flow mass balances, construction of flood management alternatives and their cumulative implementation, budget allocations, and binary decisions. Damages are adjusted for flood control investments. In recognition of the deep uncertainty of GCM-derived climate change scenarios, we employ the minimax regret criterion to identify adaptation portfolios robust to different climate change trajectories. As an example, we identify publicly and privately funded adaptation measures for a stylized community based on the estuarine community of Exeter, New Hampshire, USA. We explore the sensitivity of recommended portfolios to different ranges of climate changes, and costs associated with economies of scale and flexible infrastructure design as well as different municipal budget constraints.

On the potential of RST approach for a continuous monitoring of flooded areas

NASA Astrophysics Data System (ADS)

Faruolo, Mariapia; Coviello, Irina; Lacava, Teodosio; Pergola, Nicola; Tramutoli, Valerio

2010-05-01

In recent decades many efforts have been made in the field of remote sensing for the management of flood risk. In fact, among all natural disasters floods are probably the most frequent, causing high human suffering and large losses. All activities designed to mitigate and manage flood risk, in order to be effective and to help civil protection agencies in limiting losses of life, human suffering and damages, need of timely information about the onset of floods, their extent, intensity and duration. At present, sensors aboard meteorological satellites, mainly thanks to their high temporal resolution, may furnish frequent and updated images, ensuring a continuous monitoring of areas involved by a flood. In particular, optical instruments on board polar satellites, like NOAA-AVHRR (National Oceanic and Atmospheric Administration-Advanced Very High Resolution Radiometer) and more recently EOS-MODIS (Earth Observing System-Moderate Resolution Imaging Spectroradiometer) have been used for dynamic flood monitoring. A robust methodology for satellite based flood monitoring and detection, named RST (Robust Satellite Technique), has been recently developed and implemented using data acquired by AVHRR and MODIS to identify flooded areas with reliability and timeliness. Such an approach, based on a multi-temporal analysis of co-located satellite records and an automatic change detection scheme, has been used to analyze floods occurred in different geographic areas and observational conditions. In detail, in order to identify flooded areas within the region of interest, the spectral behavior of water in the visible (VIS) and near infrared (NIR) bands of such satellite systems has been successfully exploited. Starting from these satisfactory results, the main purpose of this paper is to show, in the case of several flooding events occurred recently in different parts of the world, the achievements arising from the use of such methodology also to data acquired in the thermal infrared (TIR) region in order to guarantee a continuous monitoring of flooded areas both during night and day.

Flood management: prediction of microbial contamination in large-scale floods in urban environments.

PubMed

Taylor, Jonathon; Lai, Ka Man; Davies, Mike; Clifton, David; Ridley, Ian; Biddulph, Phillip

2011-07-01

With a changing climate and increased urbanisation, the occurrence and the impact of flooding is expected to increase significantly. Floods can bring pathogens into homes and cause lingering damp and microbial growth in buildings, with the level of growth and persistence dependent on the volume and chemical and biological content of the flood water, the properties of the contaminating microbes, and the surrounding environmental conditions, including the restoration time and methods, the heat and moisture transport properties of the envelope design, and the ability of the construction material to sustain the microbial growth. The public health risk will depend on the interaction of these complex processes and the vulnerability and susceptibility of occupants in the affected areas. After the 2007 floods in the UK, the Pitt review noted that there is lack of relevant scientific evidence and consistency with regard to the management and treatment of flooded homes, which not only put the local population at risk but also caused unnecessary delays in the restoration effort. Understanding the drying behaviour of flooded buildings in the UK building stock under different scenarios, and the ability of microbial contaminants to grow, persist, and produce toxins within these buildings can help inform recovery efforts. To contribute to future flood management, this paper proposes the use of building simulations and biological models to predict the risk of microbial contamination in typical UK buildings. We review the state of the art with regard to biological contamination following flooding, relevant building simulation, simulation-linked microbial modelling, and current practical considerations in flood remediation. Using the city of London as an example, a methodology is proposed that uses GIS as a platform to integrate drying models and microbial risk models with the local building stock and flood models. The integrated tool will help local governments, health authorities, insurance companies and residents to better understand, prepare for and manage a large-scale flood in urban environments. Copyright © 2011 Elsevier Ltd. All rights reserved.

Adaptation to flooding during emergence and seedling growth in rice and weeds, and implications for crop establishment

PubMed Central

Ismail, Abdelbagi M.; Johnson, David E.; Ella, Evangelina S.; Vergara, Georgina V.; Baltazar, Aurora M.

2012-01-01

Background and aims Direct seeding of rice is being adopted in rainfed and irrigated lowland ecosystems because it reduces labour costs in addition to other benefits. However, early flooding due to uneven fields or rainfall slows down seed germination and hinders crop establishment. Conversely, early flooding helps suppress weeds and reduces the costs of manual weeding and/or dependence on herbicides; however, numerous weed species are adapted to lowlands and present challenges for the use of flooding to control weeds. Advancing knowledge on the mechanisms of tolerance of flooding during germination and early growth in rice and weeds could facilitate the development of improved rice varieties and effective weed management practices for direct-seeded rice. Principal results Rice genotypes with a greater ability to germinate and establish in flooded soils were identified, providing opportunities to develop varieties suitable for direct seeding in flooded soils. Tolerance of flooding in these genotypes was mostly attributed to traits associated with better ability to mobilize stored carbohydrates and anaerobic metabolism. Limited studies were undertaken in weeds associated with lowland rice systems. Remaining studies compared rice and weeds and related weed species such as Echinochloa crus-galli and E. colona or compared ecotypes of the same species of Cyperus rotundus adapted to either aerobic or flooded soils. Conclusions Tolerant weeds and rice genotypes mostly developed similar adaptive traits that allow them to establish in flooded fields, including the ability to germinate and elongate faster under hypoxia, mobilize stored starch reserves and generate energy through fermentation pathways. Remarkably, some weeds developed additional traits such as larger storage tubers that enlarge further in deeper flooded soils (C. rotundus). Unravelling the mechanisms involved in adaptation to flooding will help design management options that will allow tolerant rice genotypes to adequately establish in flooded soils while simultaneously suppressing weeds. PMID:22957137

Coupled hydrogeomorphic and woody-seedling responses to controlled flood releases in a dryland river

USGS Publications Warehouse

Wilcox, Andrew C.; Shafroth, Patrick B.

2013-01-01

Interactions among flow, geomorphic processes, and riparian vegetation can strongly influence both channel form and vegetation communities. To investigate such interactions, we took advantage of a series of dam-managed flood releases that were designed in part to maintain a native riparian woodland system on a sand-bed, dryland river, the Bill Williams River, Arizona, USA. Our resulting multiyear flow experiment examined differential mortality among native and nonnative riparian seedlings, associated flood hydraulics and geomorphic changes, and the temporal evolution of feedbacks among vegetation, channel form, and hydraulics. We found that floods produced geomorphic and vegetation responses that varied with distance downstream of a dam, with scour and associated seedling mortality closer to the dam and aggradation and burial-induced mortality in a downstream reach. We also observed significantly greater mortality among nonnative tamarisk (Tamarix) seedlings than among native willow (Salix gooddingii) seedlings, reflecting the greater first-year growth of willow relative to tamarisk. When vegetation was small early in our study period, the effects of vegetation on flood hydraulics and on mediating flood-induced channel change were minimal. Vegetation growth in subsequent years resulted in stronger feedbacks, such that vegetation's stabilizing effect on bars and its drag effect on flow progressively increased, muting the geomorphic effects of a larger flood release. These observations suggest that the effectiveness of floods in producing geomorphic and ecological changes varies not only as a function of flood magnitude and duration, but also of antecedent vegetation density and size.

Reducing uncertainty with flood frequency analysis: The contribution of paleoflood and historical flood information

NASA Astrophysics Data System (ADS)

Lam, Daryl; Thompson, Chris; Croke, Jacky; Sharma, Ashneel; Macklin, Mark

2017-03-01

Using a combination of stream gauge, historical, and paleoflood records to extend extreme flood records has proven to be useful in improving flood frequency analysis (FFA). The approach has typically been applied in localities with long historical records and/or suitable river settings for paleoflood reconstruction from slack-water deposits (SWDs). However, many regions around the world have neither extensive historical information nor bedrock gorges suitable for SWDs preservation and paleoflood reconstruction. This study from subtropical Australia demonstrates that confined, semialluvial channels such as macrochannels provide relatively stable boundaries over the 1000-2000 year time period and the preserved SWDs enabled paleoflood reconstruction and their incorporation into FFA. FFA for three sites in subtropical Australia with the integration of historical and paleoflood data using Bayesian Inference methods showed a significant reduction in uncertainty associated with the estimated discharge of a flood quantile. Uncertainty associated with estimated discharge for the 1% Annual Exceedance Probability (AEP) flood is reduced by more than 50%. In addition, sensitivity analysis of possible within-channel boundary changes shows that FFA is not significantly affected by any associated changes in channel capacity. Therefore, a greater range of channel types may be used for reliable paleoflood reconstruction by evaluating the stability of inset alluvial units, thereby increasing the quantity of temporal data available for FFA. The reduction in uncertainty, particularly in the prediction of the ≤1% AEP design flood, will improve flood risk planning and management in regions with limited temporal flood data.

A Fresh Start for Flood Estimation in Ungauged UK Catchments

NASA Astrophysics Data System (ADS)

Giani, Giulia; Woods, Ross

2017-04-01

The standard regression-based method for estimating the median annual flood in ungauged UK catchments has a high standard error (95% confidence interval is +/- a factor of 2). This is also the dominant source of uncertainty in statistical estimates of the 100-year flood. Similarly large uncertainties have been reported elsewhere. These large uncertainties make it difficult to do reliable flood design estimates for ungauged catchments. If the uncertainty could be reduced, flood protection schemes could be made significantly more cost-effective. Here we report on attempts to develop a new practical method for flood estimation in ungauged UK catchments, by making more use of knowledge about rainfall-runoff processes. Building on recent research on the seasonality of flooding, we first classify more than 1000 UK catchments into groups according to the seasonality of extreme rainfall and floods, and infer possible causal mechanisms for floods (e.g. Berghuijs et al, Geophysical Research Letters, 2016). For each group we are developing simplified rainfall-runoff-routing relationships (e.g. Viglione et al, Journal of Hydrology, 2010) which can account for spatial and temporal variability in rainfall and flood processes, as well as channel network routing effects. An initial investigation by Viglione et al suggested that the relationship between rainfall amount and flood peak could be summarised through a dimensionless response number that represents the product of the event runoff coefficient and a measure of hydrograph peakedness. Our hypothesis is that this approach is widely applicable, and can be used as the basis for flood estimation. Using subdaily and daily rainfall-runoff data for more than 1000 catchments, we identify a subset of catchments in the west of the UK where floods are generated predominantly in winter through the coincidence of heavy rain and low soil moisture deficits. Floods in these catchments can reliably be simulated with simple rainfall-runoff models, so it is reasonable to expect simple flood estimators. We will report on tests of the several components of the dimensionless response number hypothesis for these catchments.

Flood study of the Suncook River in Epsom, Pembroke, and Allenstown, New Hampshire, 2009

USGS Publications Warehouse

Flynn, Robert H.

2010-01-01

On May 15, 2006, a breach in the riverbank caused an avulsion in the Suncook River in Epsom, NH. The breach in the riverbank and subsequent avulsion changed the established flood zones along the Suncook River; therefore, a new flood study was needed to reflect this change and aid in flood recovery and restoration. For this flood study, the hydrologic and hydraulic analyses for the Suncook River were conducted by the U.S. Geological Survey, in cooperation with the Federal Emergency Management Agency. This report presents water-surface elevations and profiles determined using the U.S. Army Corps of Engineers one-dimensional Hydrologic Engineering Center River Analysis System model, also known as HEC-RAS. Steady-state water-surface profiles were developed for the Suncook River from its confluence with the Merrimack River in the Village of Suncook (in Allenstown and Pembroke, NH) to the upstream corporate limit of the town of Epsom, NH (approximately 15.9 river miles). Floods of magnitudes that are expected to be equaled or exceeded once on the average during any 2-, 5-, 10-, 25-, 50-, 100-, or 500-year period (recurrence interval) were modeled using HEC-RAS. These flood events are referred to as the 2-, 5-, 10-, 25-, 50-, 100-, and 500-year floods and have a 50-, 20-, 10-, 4-, 2-, 1-, and 0.2-percent chance, respectively, of being equaled or exceeded during any year. The 10-, 50-, 100-, and 500-year flood events are important for flood-plain management, determination of flood-insurance rates, and design of structures such as bridges and culverts. The analyses in this study reflect flooding potentials that are based on existing conditions in the communities of Epsom, Pembroke, and Allenstown at the time of completion of this study (2009). Changes in the 100-year recurrence-interval flood elevation from the 1979 flood study were typically less than 2 feet with the exception of a location 900 feet upstream from the avulsion that, because of backwater from the dams in the abandoned channel, was 12 feet higher in the 1979 flood study than in this study.

Impacts of future climate change on urban flood volumes in Hohhot in northern China: benefits of climate change mitigation and adaptations

NASA Astrophysics Data System (ADS)

Zhou, Qianqian; Leng, Guoyong; Huang, Maoyi

2018-01-01

As China becomes increasingly urbanised, flooding has become a regular occurrence in its major cities. Assessing the effects of future climate change on urban flood volumes is crucial to informing better management of such disasters given the severity of the devastating impacts of flooding (e.g. the 2016 flooding events across China). Although recent studies have investigated the impacts of future climate change on urban flooding, the effects of both climate change mitigation and adaptation have rarely been accounted for together in a consistent framework. In this study, we assess the benefits of mitigating climate change by reducing greenhouse gas (GHG) emissions and locally adapting to climate change by modifying drainage systems to reduce urban flooding under various climate change scenarios through a case study conducted in northern China. The urban drainage model - Storm Water Management Model - was used to simulate urban flood volumes using current and two adapted drainage systems (i.e. pipe enlargement and low-impact development, LID), driven by bias-corrected meteorological forcing from five general circulation models in the Coupled Model Intercomparison Project Phase 5 archive. Results indicate that urban flood volume is projected to increase by 52 % over 2020-2040 compared to the volume in 1971-2000 under the business-as-usual scenario (i.e. Representative Concentration Pathway (RCP) 8.5). The magnitudes of urban flood volumes are found to increase nonlinearly with changes in precipitation intensity. On average, the projected flood volume under RCP 2.6 is 13 % less than that under RCP 8.5, demonstrating the benefits of global-scale climate change mitigation efforts in reducing local urban flood volumes. Comparison of reduced flood volumes between climate change mitigation and local adaptation (by improving drainage systems) scenarios suggests that local adaptation is more effective than climate change mitigation in reducing future flood volumes. This has broad implications for the research community relative to drainage system design and modelling in a changing environment. This study highlights the importance of accounting for local adaptation when coping with future urban floods.

Upstream Structural Management Measures for an Urban Area Flooding in Turkey and their Consequences on Flood Risk Management

NASA Astrophysics Data System (ADS)

Akyurek, Z.; Bozoglu, B.; Girayhan, T.

2015-12-01

Flooding has the potential to cause significant impacts to economic activities as well as to disrupt or displace populations. Changing climate regimes such as extreme precipitation events increase flood vulnerability and put additional stresses on infrastructure. In this study the flood modelling in an urbanized area, namely Samsun-Terme in Blacksea region of Turkey is done. MIKE21 with flexible grid is used in 2- dimensional shallow water flow modelling. 1/1000 scaled maps with the buildings for the urbanized area and 1/5000 scaled maps for the rural parts are used to obtain DTM needed in the flood modelling. The bathymetry of the river is obtained from additional surveys. The main river passing through the urbanized area has a capacity of Q5 according to the design discharge obtained by simple ungauged discharge estimation depending on catchment area only. The effects of the available structures like bridges across the river on the flooding are presented. The upstream structural measures are studied on scenario basis. Four sub-catchments of Terme River are considered as contributing the downstream flooding. The existing circumstance of the Terme River states that the meanders of the river have a major effect on the flood situation and lead to approximately 35% reduction in the peak discharge between upstream and downstream of the river. It is observed that if the flow from the upstream catchments can be retarded through a detention pond constructed in at least two of the upstream catchments, estimated Q100 flood can be conveyed by the river without overtopping from the river channel. The operation of the upstream detention ponds and the scenarios to convey Q500 without causing flooding are also presented. Structural management measures to address changes in flood characteristics in water management planning are discussed. Flood risk is obtained by using the flood hazard maps and water depth-damage functions plotted for a variety of building types and occupancies. The estimated mean annual hazard for the area is calculated as $340 000 and it is estimated that the upstream structural management measures can decrease the direct economic risk 11% for the 500 return period flood.

Impacts of future climate change on urban flood volumes in Hohhot in northern China: benefits of climate change mitigation and adaptations

DOE PAGES

Zhou, Qianqian; Leng, Guoyong; Huang, Maoyi

2018-01-15

As China becomes increasingly urbanised, flooding has become a regular occurrence in its major cities. Assessing the effects of future climate change on urban flood volumes is crucial to informing better management of such disasters given the severity of the devastating impacts of flooding (e.g. the 2016 flooding events across China). Although recent studies have investigated the impacts of future climate change on urban flooding, the effects of both climate change mitigation and adaptation have rarely been accounted for together in a consistent framework. In this study, we assess the benefits of mitigating climate change by reducing greenhouse gas (GHG)more » emissions and locally adapting to climate change by modifying drainage systems to reduce urban flooding under various climate change scenarios through a case study conducted in northern China. The urban drainage model – Storm Water Management Model – was used to simulate urban flood volumes using current and two adapted drainage systems (i.e. pipe enlargement and low-impact development, LID), driven by bias-corrected meteorological forcing from five general circulation models in the Coupled Model Intercomparison Project Phase 5 archive. Results indicate that urban flood volume is projected to increase by 52 % over 2020–2040 compared to the volume in 1971–2000 under the business-as-usual scenario (i.e. Representative Concentration Pathway (RCP) 8.5). The magnitudes of urban flood volumes are found to increase nonlinearly with changes in precipitation intensity. On average, the projected flood volume under RCP 2.6 is 13 % less than that under RCP 8.5, demonstrating the benefits of global-scale climate change mitigation efforts in reducing local urban flood volumes. Comparison of reduced flood volumes between climate change mitigation and local adaptation (by improving drainage systems) scenarios suggests that local adaptation is more effective than climate change mitigation in reducing future flood volumes. This has broad implications for the research community relative to drainage system design and modelling in a changing environment. Furthermore, this study highlights the importance of accounting for local adaptation when coping with future urban floods.« less

Flood Hazard Mapping Assessment for Lebanon

NASA Astrophysics Data System (ADS)

Abdallah, Chadi; Darwich, Talal; Hamze, Mouin; Zaarour, Nathalie

2014-05-01

Of all natural disasters, floods affect the greatest number of people worldwide and have the greatest potential to cause damage. In fact, floods are responsible for over one third of people affected by natural disasters; almost 190 million people in more than 90 countries are exposed to catastrophic floods every year. Nowadays, with the emerging global warming phenomenon, this number is expected to increase, therefore, flood prediction and prevention has become a necessity in many places around the globe to decrease damages caused by flooding. Available evidence hints at an increasing frequency of flooding disasters being witnessed in the last 25 years in Lebanon. The consequences of such events are tragic including annual financial losses of around 15 million dollars. In this work, a hydrologic-hydraulic modeling framework for flood hazard mapping over Lebanon covering 19 watershed was introduced. Several empirical, statistical and stochastic methods to calculate the flood magnitude and its related return periods, where rainfall and river gauge data are neither continuous nor available on a long term basis with an absence of proper river sections that under estimate flows during flood events. TRMM weather satellite information, automated drainage networks, curve numbers and other geometrical characteristics for each basin was prepared using WMS-software and then exported into HMS files to implement the hydrologic modeling (rainfall-runoff) for single designed storm of uniformly distributed depth along each basin. The obtained flow hydrographs were implemented in the hydraulic model (HEC-RAS) where relative water surface profiles are calculated and flood plains are delineated. The model was calibrated using the last flood event of January 2013, field investigation, and high resolution satellite images. Flow results proved to have an accuracy ranging between 83-87% when compared to the computed statistical and stochastic methods. Results included the generation of recurrence flood plain maps of 10, 50 & 100 years intensity maps along with flood hazard maps for each watershed. It is of utmost significance for this study to be effective that the produced flood intensity and hazard maps will be made available to decision-makers, planners and relevant community stakeholders.

Impacts of future climate change on urban flood volumes in Hohhot in northern China: benefits of climate change mitigation and adaptations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Qianqian; Leng, Guoyong; Huang, Maoyi

As China becomes increasingly urbanised, flooding has become a regular occurrence in its major cities. Assessing the effects of future climate change on urban flood volumes is crucial to informing better management of such disasters given the severity of the devastating impacts of flooding (e.g. the 2016 flooding events across China). Although recent studies have investigated the impacts of future climate change on urban flooding, the effects of both climate change mitigation and adaptation have rarely been accounted for together in a consistent framework. In this study, we assess the benefits of mitigating climate change by reducing greenhouse gas (GHG)more » emissions and locally adapting to climate change by modifying drainage systems to reduce urban flooding under various climate change scenarios through a case study conducted in northern China. The urban drainage model – Storm Water Management Model – was used to simulate urban flood volumes using current and two adapted drainage systems (i.e. pipe enlargement and low-impact development, LID), driven by bias-corrected meteorological forcing from five general circulation models in the Coupled Model Intercomparison Project Phase 5 archive. Results indicate that urban flood volume is projected to increase by 52 % over 2020–2040 compared to the volume in 1971–2000 under the business-as-usual scenario (i.e. Representative Concentration Pathway (RCP) 8.5). The magnitudes of urban flood volumes are found to increase nonlinearly with changes in precipitation intensity. On average, the projected flood volume under RCP 2.6 is 13 % less than that under RCP 8.5, demonstrating the benefits of global-scale climate change mitigation efforts in reducing local urban flood volumes. Comparison of reduced flood volumes between climate change mitigation and local adaptation (by improving drainage systems) scenarios suggests that local adaptation is more effective than climate change mitigation in reducing future flood volumes. This has broad implications for the research community relative to drainage system design and modelling in a changing environment. Furthermore, this study highlights the importance of accounting for local adaptation when coping with future urban floods.« less

Flood mapping in ungauged basins using fully continuous hydrologic-hydraulic modeling

NASA Astrophysics Data System (ADS)

Grimaldi, Salvatore; Petroselli, Andrea; Arcangeletti, Ettore; Nardi, Fernando

2013-04-01

SummaryIn this work, a fully-continuous hydrologic-hydraulic modeling framework for flood mapping is introduced and tested. It is characterized by a simulation of a long rainfall time series at sub-daily resolution that feeds a continuous rainfall-runoff model producing a discharge time series that is directly given as an input to a bi-dimensional hydraulic model. The main advantage of the proposed approach is to avoid the use of the design hyetograph and the design hydrograph that constitute the main source of subjective analysis and uncertainty for standard methods. The proposed procedure is optimized for small and ungauged watersheds where empirical models are commonly applied. Results of a simple real case study confirm that this experimental fully-continuous framework may pave the way for the implementation of a less subjective and potentially automated procedure for flood hazard mapping.

Advances in urban-drainage management and flood protection.

PubMed

Verworn, Hans-Reinhard

2002-07-15

Since the beginning of modern urban drainage in the 19th century, the sole objective has been to get rid of sewage and storm water in the best possible way and design the systems according to accepted standards. In recent decades, advanced methods have been developed not only to refine the design but also especially to enable the assessment of hydraulic performance and pollutant emissions. Consequently, urban drainage has become part of an integrated approach concerning flood protection as well as ecological aspects for whole watersheds. Another major change concerns the management of urban systems: simple structural maintenance has been replaced by interactive operational management and control of the systems in order to make better use of the facilities. Rehabilitation has become a multi-objective task. This paper looks at today's basic principles of urban drainage and tomorrow's potential advances, and deals with their relevance to flood protection.

A simulation for the gated weir opening of Wonokromo River, Rungkut District, Surabaya

NASA Astrophysics Data System (ADS)

Handajani, N.; Wahjudijanto, I.; Mu'afi, M.

2018-01-01

The gated weir is a weir that the crest elevation could be operated based on the flow through the river. The upstream water level of the gated weir could be controlled with gate opening or closing. This study applied a simulation with HEC-RAS 4,0 program in order to know the river hydraulic condition after the gated weir has built. According to the rainfall intensity from each sub-watershed, Distribution Log Pearson III with return period 50 years (Q50) was determined to calculate the design flood discharge. By using Rational Method, the design flood discharge is 470 m3/s. The Results show that capacity of the river is able to accomodate Q50 with discharge 470 m3/s and the gate should be fully opened during flood. This condition could passed the normal discharge at + 5.00 m elevation.

A history of flooding in the Red River Basin

USGS Publications Warehouse

Ryberg, Karen R.; Macek-Rowland, Kathleen M.; Banse, Tara A.; Wiche, Gregg J.; Martin, Cathy R.

2007-01-01

The U.S. Geological Survey (USGS), one of the principal Federal agencies responsible for the collection and interpretation of water-resources data, works with other Federal, State, local, tribal, and academic entities to ensure that accurate and timely data are available for making decisions regarding public welfare and property during natural disasters and to increase public awareness of the hazards that occur with such disasters. The Red River of the North Basin has a history of flooding and this poster is designed to increase public awareness of that history and of the factors that contribute to flooding.

Thermosyphon Flooding in Reduced Gravity Environments Test Results

NASA Technical Reports Server (NTRS)

Gibson, Marc A.; Jaworske, Donald A.; Sanzi, Jim; Ljubanovic, Damir

2013-01-01

The condenser flooding phenomenon associated with gravity aided two-phase thermosyphons was studied using parabolic flights to obtain the desired reduced gravity environment (RGE). The experiment was designed and built to test a total of twelve titanium water thermosyphons in multiple gravity environments with the goal of developing a model that would accurately explain the correlation between gravitational forces and the maximum axial heat transfer limit associated with condenser flooding. Results from laboratory testing and parabolic flights are included in this report as part I of a two part series. The data analysis and correlations are included in a follow on paper.

Socio-Economic Resilience to Floods in 90 Countries

NASA Astrophysics Data System (ADS)

Hallegatte, S.; Bangalore, M.; Vogt-Schilb, A.

2015-12-01

Global losses from floods are increasing, with renewed calls for action to reduce their impact. In each country, region or city, many actions can protect the population and help rebuild and recover: building dikes and restoring mangroves; land-use planning; early warning and evacuation; insurance and social safety nets. What should be the priorities? How to build a comprehensive strategy? Is progress being made? We propose a tool - a national-level scorecard based on welfare economics - to assess a country's socio-economic resilience to river floods and identify the most promising policy options in different contexts to reduce the impact of floods on well-being. The tool is applied to 90 countries using open databases, and can serve as a starting point for designing policies and more in-depth local studies.

Experimental Study on Oil Displacement Mechanism

NASA Astrophysics Data System (ADS)

Pi, Yanfu; Shao, Hongzhi; Pi, Yanming; Liu, Li

2018-02-01

In this work, the objective is enhancing oil recovery in offshore heavy oil after polymer flooding. The heterogeneous physical model is especially designed for oil fields with heavy oil. The comparative study of the two displacement experiments was carried out, and the experimental data was compared and analysed. The comparison between scheme one and scheme two was analysed from the production curve. The patterns of cores are analysed and compared with each other. It was found that the oil in the high permeability layer and medium permeability layer had been widely removed in the stage of binary combination flooding. There was a high degree of use in the low permeability layer. The recovery ratio is 66.29%. After polymer flooding, the addition of binary combination flooding in the heavy oil reservoir can greatly enhance oil recovery.

Design Guide for Improving School Safety in Earthquakes, Floods, and High Winds. Risk Management Series. FEMA 424

ERIC Educational Resources Information Center

Arnold, Christopher; Lyons, Jack; Munger, James; Quinn, Rebecca C.; Smith, Thomas L.

2004-01-01

This manual is intended to provide guidance for the protection of school buildings and their occupants from natural disasters, and the economic losses and social disruption caused by building damage and destruction. This volume concentrates on grade schools, K-12. This publication covers earthquakes, floods, and high winds. Its intended audience…

Flood tolerance evaluation of bottomland oaks in a multi-channel field laboratory

Treesearch

Mark V. Coggeshall; J. W. Van Sambeek; Scott E. Schlarbaum

2005-01-01

A multi-channel field laboratory was designed and constructed by the University of Missouri Center for Agroforestry at the Horticulture and Agroforestry Research Center to assess the flood tolerance of forages and hardwood seedlings. This facility located in the Missouri River floodplain consists of twelve 6-m wide x 180-m long channels that had minimal disturbance to...

Modelling large floating bodies in urban area flash-floods via a Smoothed Particle Hydrodynamics model

NASA Astrophysics Data System (ADS)

Albano, Raffaele; Sole, Aurelia; Mirauda, Domenica; Adamowski, Jan

2016-10-01

Large debris, including vehicles parked along floodplains, can cause severe damage and significant loss of life during urban area flash-floods. In this study, the authors validated and applied the Smoothed Particle Hydrodynamics (SPH) model, developed in Amicarelli et al. (2015), which reproduces in 3D the dynamics of rigid bodies driven by free surface flows, to the design of flood mitigation measures. To validate the model, the authors compared the model's predictions to the results of an experimental setup, involving a dam breach that strikes two fixed obstacles and three transportable floating bodies. Given the accuracy of the results, in terms of water depth over time and the time history of the bodies' movements, the SPH model explored in this study was used to analyse the mitigation efficiency of a proposed structural intervention - the use of small barriers (groynes) to prevent the transport of floating bodies. Different groynes configurations were examined to identify the most appropriate design and layout for urban area flash-flood damage mitigation. The authors found that groynes positioned upstream and downstream of each floating body can be effective as a risk mitigation measure for damage resulting from their movement.

The enhancement of adaptation and psychological well-being among victims of flooding and landslide in Thailand.

PubMed

Oba, Nongnut; Suntayakorn, Chanjar; Sangkaewsri, Roongsri; Longchupol, Chaowanee; Lohitpintu, Itsareat; Kumsri, Tongbai

2010-03-01

To explore the needs of potential enhancement for adaptation and to examine the effectiveness of the potential enhancement program for adaptation and psychological well-being among victims of flooding and landslide in Lublae district Uttaradit Province, Thailand. 3 step of research and development; the needs of potential enhancement for adaptation among victims of flooding and landslide were analyzed by focus group discussion, the potential enhancement program (PEP) was designed by brainstorming of three groups of stakeholder; victims, health volunteers and health personnel and the effectiveness of PEP was tested by the difference of adaptation and psychological well-being perception among victims of flooding and landslide between before and after intervention. Thumbun Maepou, Lublae district, Uttaradit Province, Thailand. The needs of potential enhancement among victims of flooding and landslide were set up warning network along the risk canal and mountain, first aid training for health volunteer, and program of psychological health promotion. The PEP composed of community flooding and landslide rehearsal training, health education and dissemination and knowledge management. Total adaptation and psychological wellbeing of samples after intervention were significantly higher than that of before intervention at 0.05 and 0.001, respectively. The restoration of adaptation and psychological well-being among victims of flooding and landslide were essential to maintained holistic health.

Methodology and implications of maximum paleodischarge estimates for mountain channels, upper Animas River basin, Colorado, U.S.A.

USGS Publications Warehouse

Pruess, J.; Wohl, E.E.; Jarrett, R.D.

1998-01-01

Historical and geologic records may be used to enhance magnitude estimates for extreme floods along mountain channels, as demonstrated in this study from the San Juan Mountains of Colorado. Historical photographs and local newspaper accounts from the October 1911 flood indicate the likely extent of flooding and damage. A checklist designed to organize and numerically score evidence of flooding was used in 15 field reconnaissance surveys in the upper Animas River valley of southwestern Colorado. Step-backwater flow modeling estimated the discharges necessary to create longitudinal flood bars observed at 6 additional field sites. According to these analyses, maximum unit discharge peaks at approximately 1.3 m3 s-1 km-2 around 2200 m elevation, with decreased unit discharges at both higher and lower elevations. These results (1) are consistent with Jarrett's (1987, 1990, 1993) maximum 2300-m elevation limit for flash-flooding in the Colorado Rocky Mountains, and (2) suggest that current Probable Maximum Flood (PMF) estimates based on a 24-h rainfall of 30 cm at elevations above 2700 m are unrealistically large. The methodology used for this study should be readily applicable to other mountain regions where systematic streamflow records are of short duration or nonexistent.

Physically-based extreme flood frequency with stochastic storm transposition and paleoflood data on large watersheds

NASA Astrophysics Data System (ADS)

England, John F.; Julien, Pierre Y.; Velleux, Mark L.

2014-03-01

Traditionally, deterministic flood procedures such as the Probable Maximum Flood have been used for critical infrastructure design. Some Federal agencies now use hydrologic risk analysis to assess potential impacts of extreme events on existing structures such as large dams. Extreme flood hazard estimates and distributions are needed for these efforts, with very low annual exceedance probabilities (⩽10-4) (return periods >10,000 years). An integrated data-modeling hydrologic hazard framework for physically-based extreme flood hazard estimation is presented. Key elements include: (1) a physically-based runoff model (TREX) coupled with a stochastic storm transposition technique; (2) hydrometeorological information from radar and an extreme storm catalog; and (3) streamflow and paleoflood data for independently testing and refining runoff model predictions at internal locations. This new approach requires full integration of collaborative work in hydrometeorology, flood hydrology and paleoflood hydrology. An application on the 12,000 km2 Arkansas River watershed in Colorado demonstrates that the size and location of extreme storms are critical factors in the analysis of basin-average rainfall frequency and flood peak distributions. Runoff model results are substantially improved by the availability and use of paleoflood nonexceedance data spanning the past 1000 years at critical watershed locations.

Rehabilitation and Flood Management Planning in a Steep, Boulder-Bedded Stream

NASA Astrophysics Data System (ADS)

Caruso, Brian S.; Downs, Peter W.

2007-08-01

This study demonstrates the integration of rehabilitation and flood management planning in a steep, boulder-bedded stream in a coastal urban catchment on the South Island of New Zealand. The Water of Leith, the primary stream flowing through the city of Dunedin, is used as a case study. The catchment is steep, with a short time of concentration and rapid hydrologic response, and the lower stream reaches are highly channelized with floodplain encroachment, a high potential for debris flows, significant flood risks, and severely degraded aquatic habitat. Because the objectives for rehabilitation and flood management in urban catchments are often conflicting, a number of types of analyses at both the catchment and the reach scales and careful planning with stakeholder consultation were needed for successful rehabilitation efforts. This included modeling and analysis of catchment hydrology, fluvial geomorphologic assessment, analysis of water quality and aquatic ecology, hydraulic modeling and flood risk evaluation, detailed feasibility studies, and preliminary design to optimize multiple rehabilitation and flood management objectives. The study showed that all of these analyses were needed for integrated rehabilitation and flood management and that some incremental improvements in stream ecological health, aesthetics, and public recreational opportunities could be achieved in this challenging environment. These methods should be considered in a range of types of stream rehabilitation projects.

Assessment of flood hazard in a combined sewer system in Reykjavik city centre.

PubMed

Hlodversdottir, Asta Osk; Bjornsson, Brynjolfur; Andradottir, Hrund Olof; Eliasson, Jonas; Crochet, Philippe

2015-01-01

Short-duration precipitation bursts can cause substantial property damage and pose operational risks for wastewater managers. The objective of this study was to assess the present and possible future flood hazard in the combined sewer system in Reykjavik city centre. The catchment is characterised by two hills separated by a plain. A large portion of the pipes in the aging network are smaller than the current minimum diameter of 250 mm. Runoff and sewer flows were modelled using the MIKE URBAN software package incorporating both historical precipitation and synthetic storms derived from annual maximum rainfall data. Results suggest that 3% of public network manholes were vulnerable to flooding during an 11-year long rainfall sequence. A Chicago Design Storm (CDS) incorporating a 10-minute rainfall burst with a 5-year return period predicted twice as many flooded manholes at similar locations. A 20% increase in CDS intensity increased the number of flooded manholes and surface flood volume by 70% and 80%, respectively. The flood volume tripled if rainfall increase were combined with urban re-development, leading to a 20% increase in the runoff coefficient. Results highlight the need for reducing network vulnerabilities, which include decreased pipe diameters and low or drastically varying pipe grades.

A real-time measurement system for long-life flood monitoring and warning applications.

PubMed

Marin-Perez, Rafael; García-Pintado, Javier; Gómez, Antonio Skarmeta

2012-01-01

A flood warning system incorporates telemetered rainfall and flow/water level data measured at various locations in the catchment area. Real-time accurate data collection is required for this use, and sensor networks improve the system capabilities. However, existing sensor nodes struggle to satisfy the hydrological requirements in terms of autonomy, sensor hardware compatibility, reliability and long-range communication. We describe the design and development of a real-time measurement system for flood monitoring, and its deployment in a flash-flood prone 650 km(2) semiarid watershed in Southern Spain. A developed low-power and long-range communication device, so-called DatalogV1, provides automatic data gathering and reliable transmission. DatalogV1 incorporates self-monitoring for adapting measurement schedules for consumption management and to capture events of interest. Two tests are used to assess the success of the development. The results show an autonomous and robust monitoring system for long-term collection of water level data in many sparse locations during flood events.

Vulnerability of schools to floods in Nyando River catchment, Kenya.

PubMed

Ochola, Samuel O; Eitel, Bernhard; Olago, Daniel O

2010-07-01

This paper assesses the vulnerability of schools to floods in the Nyando River catchment (3,600 km(2)) in western Kenya and identifies measures needed to reduce this vulnerability. It surveys 130 schools in the lower reaches, where flooding is a recurrent phenomenon. Of the primary schools assessed, 40% were vulnerable, 48% were marginally vulnerable and 12% were not vulnerable. Of the secondary schools, 8% were vulnerable, 73% were marginally vulnerable and 19% were not vulnerable. Vulnerability to floods is due to a lack of funds, poor building standards, local topography, soil types and inadequate drainage. The Constituencies Development Fund (CDF), established in 2003, provides financial support to cover school construction and reconstruction costs; CDF Committees are expected to adopt school building standards. In an effort to promote safe and resilient construction and retrofitting to withstand floods, this paper presents vulnerability reduction strategies and recommendations for incorporating minimum standards in the on-going Primary School Infrastructure Programme Design.

A Real-Time Measurement System for Long-Life Flood Monitoring and Warning Applications

PubMed Central

Marin-Perez, Rafael; García-Pintado, Javier; Gómez, Antonio Skarmeta

2012-01-01

A flood warning system incorporates telemetered rainfall and flow/water level data measured at various locations in the catchment area. Real-time accurate data collection is required for this use, and sensor networks improve the system capabilities. However, existing sensor nodes struggle to satisfy the hydrological requirements in terms of autonomy, sensor hardware compatibility, reliability and long-range communication. We describe the design and development of a real-time measurement system for flood monitoring, and its deployment in a flash-flood prone 650 km2 semiarid watershed in Southern Spain. A developed low-power and long-range communication device, so-called DatalogV1, provides automatic data gathering and reliable transmission. DatalogV1 incorporates self-monitoring for adapting measurement schedules for consumption management and to capture events of interest. Two tests are used to assess the success of the development. The results show an autonomous and robust monitoring system for long-term collection of water level data in many sparse locations during flood events. PMID:22666028

Hurricane Impacts on Small Island Communities: Case study of Hurricane Matthew on Great Exuma, The Bahamas

NASA Astrophysics Data System (ADS)

Sullivan Sealey, Kathleen; Bowleg, John

2017-04-01

Great Exuma has been a UNESCO Eco-hydrology Project Site with a focus on coastal restoration and flood management. Great Exuma and its largest settlement, George Town, support a population of just over 8.000 people on an island dominated by extensive coastal wetlands. The Victoria Pond Eco-Hydrology project restored flow and drainage to highly-altered coastal wetlands to reduce flooding of the built environment as well as regain ecological function. The project was designed to show the value of a protected wetland and coastal environment within a populated settlement; demonstrating that people can live alongside mangroves and value "green" infrastructure for flood protection. The restoration project was initiated after severe storm flooding in 2007 with Tropical Storm Noel. In 2016, the passing of Hurricane Matthew had unprecedented impacts on the coastal communities of Great Exuma, challenging past practices in restoration and flood prevention. This talk reviews the loss of natural capital (for example, fish populations, mangroves, salt water inundation) from Hurricane Matthew based on a rapid response survey of Great Exuma. The surprisingly find was the impact of storm surge on low-lying areas used primarily for personal farms and small-scale agriculture. Although women made up the overwhelming majority of people who attended Coastal Restoration workshops, women were most adversely impacted by the recent hurricane flooding with the loss of their small low-lying farms and gardens. Although increasing culverts in mangrove creeks in two areas did reduce building flood damage, the low-lying areas adjacent to mangroves, mostly ephemeral freshwater wetlands, were inundated with saltwater, and seasonal crops in these areas were destroyed. These ephemeral wetlands were designed as part of the wetland flooding system, it was not known how important these small areas were to artisanal farming on Great Exuma. The size and scope of Hurricane Matthew passing through the entire country presents a unique opportunity use a rapid response method to document coastal impacts to better understand how to plan coastal restoration. Small farms managed primarily by women accounted for about 35% of the fresh produce eaten by local Bahamians (not tourists), and the loss of local production may be permanent.

Evaluation of Carrying Capacity Land-Based Layout to Mitigate Flood Risk (Case Study in Tempuran Floodplain, Ponorogo Regency) Novia Lusiana1 Bambang Rahadi2 Tunggul Sutanhaji3 1Environmental and Natural Resources Management Graduate Program University of Brawijaya, Malang, Indonesia 23Laboratory of Environment and Natural Resources Engineering, Department of Agricultural Engineering, Faculty of Agricultural Technology, University of Brawijaya, Malang, Indonesia Email : novialusiana@rocketmail.com, jbrahadi@ub.ac.id, tunggulsutanhaji@yahoo.com

NASA Astrophysics Data System (ADS)

Lusiana, N.

2013-12-01

Abstract Floods haves frequently hit Indonesia and have had greater negative impacts. In Javaboth the area affected by flooding and the amount of damage caused by floods have increased. At least, five factors, affect the flooding in Indonesia, including rainfall, reduced retention capacity of the watershed, erroneous design of river channel development, silting-up of the river, and erroneous regional layout. The level of the disastrous risks can be evaluated based on the extent of the threat and susceptibility of a region. One methode for risk assessment is Geographical Information System (GIS)-based mapping. Objectives of this research are: 1) evaluating current flood risk in susceptible areas, 2) applying supported land-based layout as effort to mitigate floodrisk, and 3) evaluating floodrisk for the period 2031 in the Tempuran floodplain of Ponorogo Regency. Result show that the area categorized as high risk covers 104. 6 ha (1. 2%), moderate risk covers 2512. 9 ha (28. 4%), low risk covers 3140. 8 ha (35. 5%), and the lowest risk covers 3096. 1 (34. 9%). Using Regional Layout Design for the years 2011 - 2031, the high risk area covers 67. 9 ha (0.8%), moderate risk covers 3033 ha (34. 3%), low risk covers 2770. 8 ha (31, 3%), and the lowest risk covers 2982. 6 ha (34%). Based on supported land suitability, the high-risk areais only 2. 9 ha (0.1%), moderate risk covers of 426. 1 ha (4. 8%), low risk covers 4207. 4 ha (47. 5%), and the lowest risk covers 4218 ha (47. 6%). Flood risk can be mitigated by applying supported land-based layout as shown by the reduced high-risk area, and the fact that > 90% of the areas are categorized as low or lowest risk of disaster. Keywords : Carrying Capacity, Land Capacity, Flood Risk

Flooding and Emergency Room Visits for Gastrointestinal Illness in Massachusetts: A Case-Crossover Study

PubMed Central

Wade, Timothy J.; Lin, Cynthia J.; Jagai, Jyotsna S.; Hilborn, Elizabeth D.

2014-01-01

Introduction Floods and other severe weather events are anticipated to increase as a result of global climate change. Floods can lead to outbreaks of gastroenteritis and other infectious diseases due to disruption of sewage and water infrastructure and impacts on sanitation and hygiene. Floods have also been indirectly associated with outbreaks through population displacement and crowding. Methods We conducted a case-crossover study to investigate the association between flooding and emergency room visits for gastrointestinal illness (ER-GI) in Massachusetts for the years 2003 through 2007. We obtained ER-GI visits from the State of Massachusetts and records of floods from the National Oceanic and Atmospheric Association’s Storm Events Database. ER-GI visits were considered exposed if a flood occurred in the town of residence within three hazard periods of the visit: 0–4 days; 5–9 days; and 10–14 days. A time-stratified bi-directional design was used for control selection, matching on day of the week with two weeks lead or lag time from the ER-GI visit. Fixed effect logistic regression models were used to estimate the risk of ER-GI visits following the flood. Results and Conclusions A total of 270,457 ER-GI visits and 129 floods occurred in Massachusetts over the study period. Across all counties, flooding was associated with an increased risk for ER-GI in the 0–4 day period after flooding (Odds Ratio: 1.08; 95% Confidence Interval: 1.03–1.12); but not the 5–9 days (Odds Ratio: 0.995; 95% Confidence Interval: 0.955–1.04) or the 10–14 days after (Odds Ratio: 0.966, 95% Confidence Interval: 0.927–1.01). Similar results were observed for different definitions of ER-GI. The effect differed across counties, suggesting local differences in the risk and impact of flooding. Statewide, across the study period, an estimated 7% of ER-GI visits in the 0–4 days after a flood event were attributable to flooding. PMID:25329916

Base (100-year) flood elevations for selected sites in Marion County, Missouri

USGS Publications Warehouse

Southard, Rodney E.; Wilson, Gary L.

1998-01-01

The primary requirement for community participation in the National Flood Insurance Program is the adoption and enforcement of floodplain management requirements that minimize the potential for flood damages to new construction and avoid aggravating existing flooding conditions. This report provides base flood elevations (BFE) for a 100-year recurrence flood for use in the management and regulation of 14 flood-hazard areas designated by the Federal Emergency Management Agency as approximate Zone A areas in Marion County, Missouri. The one-dimensional surface-water flow model, HEC-RAS, was used to compute the base (100-year) flood elevations for the 14 Zone A sites. The 14 sites were located at U.S., State, or County road crossings and the base flood elevation was determined at the upstream side of each crossing. The base (100-year) flood elevations for BFE 1, 2, and 3 on the South Fork North River near Monroe City, Missouri, are 627.7, 579.2, and 545.9 feet above sea level. The base (100-year) flood elevations for BFE 4, 5, 6, and 7 on the main stem of the North River near or at Philadelphia and Palmyra, Missouri, are 560.5, 539.7, 504.2, and 494.4 feet above sea level. BFE 8 is located on Big Branch near Philadelphia, a tributary to the North River, and the base (100-year) flood elevation at this site is 530.5 feet above sea level. One site (BFE 9) is located on the South River near Monroe City, Missouri. The base (100-year) flood elevation at this site is 619.1 feet above sea level. Site BFE 10 is located on Bear Creek near Hannibal, Missouri, and the base (100-year) elevation is 565.5 feet above sea level. The four remaining sites (BFE 11, 12, 13, and 14) are located on the South Fabius River near Philadelphia and Palmyra, Missouri. The base (100-year) flood elevations for BFE 11, 12, 13, and 14 are 591.2, 578.4, 538.7, and 506.9 feet above sea level.

Somerset County Flood Information System

USGS Publications Warehouse

Hoppe, Heidi L.

2007-01-01

The timely warning of a flood is crucial to the protection of lives and property. One has only to recall the floods of August 2, 1973, September 16 and 17, 1999, and April 16, 2007, in Somerset County, New Jersey, in which lives were lost and major property damage occurred, to realize how costly, especially in terms of human life, an unexpected flood can be. Accurate forecasts and warnings cannot be made, however, without detailed information about precipitation and streamflow in the drainage basin. Since the mid 1960's, the National Weather Service (NWS) has been able to forecast flooding on larger streams in Somerset County, such as the Raritan and Millstone Rivers. Flooding on smaller streams in urban areas was more difficult to predict. In response to this problem the NWS, in cooperation with the Green Brook Flood Control Commission, installed a precipitation gage in North Plainfield, and two flash-flood alarms, one on Green Brook at Seeley Mills and one on Stony Brook at Watchung, in the early 1970's. In 1978, New Jersey's first countywide flood-warning system was installed by the U.S. Geological Survey (USGS) in Somerset County. This system consisted of a network of eight stage and discharge gages equipped with precipitation gages linked by telephone telemetry and eight auxiliary precipitation gages. The gages were installed throughout the county to collect precipitation and runoff data that could be used to improve flood-monitoring capabilities and flood-frequency estimates. Recognizing the need for more detailed hydrologic information for Somerset County, the USGS, in cooperation with Somerset County, designed and installed the Somerset County Flood Information System (SCFIS) in 1990. This system is part of a statewide network of stream gages, precipitation gages, weather stations, and tide gages that collect data in real time. The data provided by the SCFIS improve the flood forecasting ability of the NWS and aid Somerset County and municipal agencies in the planning and execution of flood-preparation and emergency-evacuation procedures in the county. This fact sheet describes the SCFIS and identifies its benefits.

Tidal dynamics in a changing lagoon: Flooding or not flooding the marginal regions

NASA Astrophysics Data System (ADS)

Lopes, Carina L.; Dias, João M.

2015-12-01

Coastal lagoons are low-lying systems under permanent changes motivated by natural and anthropogenic factors. Ria de Aveiro is such an example with its margins currently threatened by the advance of the lagoonal waters recorded during the last decades. This work aims to study the tidal modifications found between 1987 and 2012 in this lagoon, motivated by the main channels deepening which induce higher inland tidal levels. Additionally it aims to study the impact that protective walls designed to protect the margins against flooding may have in those modifications under sea level rise predictions. The hydrodynamic model ELCIRC previously calibrated for Ria de Aveiro was used and tidal asymmetry, tidal ellipses and residual currents were analyzed for different scenarios, considering the mean sea level rise predicted for 2100 and the implementation of probable flood protection walls. Results evidenced that lagoon dominance remained unchanged between 1987 and 2012, but distortion decreased/increased in the deeper/shallower channels. The same trend was found under mean sea level rise conditions. Tidal currents increased over this period inducing an amplification of the water properties exchange within the lagoon, which will be stronger under mean sea level rise conditions. The deviations between scenarios with or without flood protection walls can achieve 60% for the tidal distortion and residual currents and 20% for the tidal currents, highlighting that tidal properties are extremely sensitive to the lagoon geometry. In summary, the development of numerical modelling applications dedicated to study the influence of mean sea level rise on coastal low-lying systems subjected to human influence should include structural measures designed for flood defence in order to accurately predict changes in the local tidal properties.

Designing an 'expert knowledge' based approach for the quantification of historical floods - the case study of the Kinzig catchment in Southwest Germany

NASA Astrophysics Data System (ADS)

Bösmeier, Annette; Glaser, Rüdiger; Stahl, Kerstin; Himmelsbach, Iso; Schönbein, Johannes

2017-04-01

Future estimations of flood hazard and risk for developing optimal coping and adaption strategies inevitably include considerations of the frequency and magnitude of past events. Methods of historical climatology represent one way of assessing flood occurrences beyond the period of instrumental measurements and can thereby substantially help to extend the view into the past and to improve modern risk analysis. Such historical information can be of additional value and has been used in statistical approaches like Bayesian flood frequency analyses during recent years. However, the derivation of quantitative values from vague descriptive information of historical sources remains a crucial challenge. We explored possibilities of parametrization of descriptive flood related data specifically for the assessment of historical floods in a framework that combines a hermeneutical approach with mathematical and statistical methods. This study forms part of the transnational, Franco-German research project TRANSRISK2 (2014 - 2017), funded by ANR and DFG, with the focus on exploring the floods history of the last 300 years for the regions of Upper and Middle Rhine. A broad data base of flood events had been compiled, dating back to AD 1500. The events had been classified based on hermeneutical methods, depending on intensity, spatial dimension, temporal structure, damages and mitigation measures associated with the specific events. This indexed database allowed the exploration of a link between descriptive data and quantitative information for the overlapping time period of classified floods and instrumental measurements since the end of the 19th century. Thereby, flood peak discharges as a quantitative measure of the severity of a flood were used to assess the discharge intervals for flood classes (upper and lower thresholds) within different time intervals for validating the flood classification, as well as examining the trend in the perception threshold over time. Furthermore, within a suitable time period, flood classes and other quantifiable indicators of flood intensity (number of damaged locations mentioned in historical sources, general availability of reports associated with a specific event) were combined with available peak discharges measurements. We argue that this information can be considered as 'expert knowledge' and used it to develop a fuzzy rule based model for deriving peak discharge estimates of pre-instrumental events that can finally be introduced into a flood frequency analysis.

Flash floods in Europe: state of the art and research perspectives

NASA Astrophysics Data System (ADS)

Gaume, Eric

2014-05-01

Flash floods, i.e. floods induced by severe rainfall events generally affecting watersheds of limited area, are the most frequent, destructive and deadly kind of natural hazard known in Europe and throughout the world. Flash floods are especially intense across the Mediterranean zone, where rainfall accumulations exceeding 500 mm within a few hours may be observed. Despite this state of facts, the study of extremes in hydrology has essentially gone unexplored until the recent past, with the exception of some rare factual reports on individual flood events, with the sporadic inclusion of isolated estimated peak discharges. Floods of extraordinary magnitude are in fact hardly ever captured by existing standard measurement networks, either because they are too heavily concentrated in space and time or because their discharges greatly exceed the design and calibration ranges of the measurement devices employed (stream gauges). This situation has gradually evolved over the last decade for two main reasons. First, the expansion and densification of weather radar networks, combined with improved radar quantitative precipitation estimates, now provide ready access to rainfall measurements at spatial and temporal scales that, while not perfectly accurate, are compatible with the study of extreme events. Heavy rainfall events no longer fail to be recorded by existing rain gauge and radar networks. Second, pioneering research efforts on extreme floods, based on precise post-flood surveys, have helped overcome the limitations imposed by a small base of available direct measured data. This activity has already yielded significant progress in expanding the knowledge and understanding of extreme flash floods. This presentation will provide a review of the recent research progresses in the area of flash flood studies, mainly based on the outcomes of the European research projects FLOODsite, HYDRATE and Hymex. It will show how intensive collation of field data helped better define the possible magnitudes of flood volumes and discharges during flash floods, their spatial distribution and rates of occurrence, as well as the factors that control the hydrological response of watersheds to heavy rainfalls explaining the large spatial variability in flood hazard. Developments in the fields of flood frequency analyses and flood forecasting based on the recently acquired data or adapted for the valuation of this specific data will also be presented. The presentation will end suggesting some perspectives for future research activities on flash floods.

Flooding and mental health: a systematic mapping review.

PubMed

Fernandez, Ana; Black, John; Jones, Mairwen; Wilson, Leigh; Salvador-Carulla, Luis; Astell-Burt, Thomas; Black, Deborah

2015-01-01

Floods are the most common type of global natural disaster. Floods have a negative impact on mental health. Comprehensive evaluation and review of the literature are lacking. To systematically map and review available scientific evidence on mental health impacts of floods caused by extended periods of heavy rain in river catchments. We performed a systematic mapping review of published scientific literature in five languages for mixed studies on floods and mental health. PUBMED and Web of Science were searched to identify all relevant articles from 1994 to May 2014 (no restrictions). The electronic search strategy identified 1331 potentially relevant papers. Finally, 83 papers met the inclusion criteria. Four broad areas are identified: i) the main mental health disorders-post-traumatic stress disorder, depression and anxiety; ii] the factors associated with mental health among those affected by floods; iii) the narratives associated with flooding, which focuses on the long-term impacts of flooding on mental health as a consequence of the secondary stressors; and iv) the management actions identified. The quantitative and qualitative studies have consistent findings. However, very few studies have used mixed methods to quantify the size of the mental health burden as well as exploration of in-depth narratives. Methodological limitations include control of potential confounders and short-term follow up. Floods following extreme events were excluded from our review. Although the level of exposure to floods has been systematically associated with mental health problems, the paucity of longitudinal studies and lack of confounding controls precludes strong conclusions. We recommend that future research in this area include mixed-method studies that are purposefully designed, using more rigorous methods. Studies should also focus on vulnerable groups and include analyses of policy and practical responses.

Flooding and Mental Health: A Systematic Mapping Review

PubMed Central

Fernandez, Ana; Black, John; Jones, Mairwen; Wilson, Leigh; Salvador-Carulla, Luis; Astell-Burt, Thomas; Black, Deborah

2015-01-01

Background Floods are the most common type of global natural disaster. Floods have a negative impact on mental health. Comprehensive evaluation and review of the literature are lacking. Objective To systematically map and review available scientific evidence on mental health impacts of floods caused by extended periods of heavy rain in river catchments. Methods We performed a systematic mapping review of published scientific literature in five languages for mixed studies on floods and mental health. PUBMED and Web of Science were searched to identify all relevant articles from 1994 to May 2014 (no restrictions). Results The electronic search strategy identified 1331 potentially relevant papers. Finally, 83 papers met the inclusion criteria. Four broad areas are identified: i) the main mental health disorders—post-traumatic stress disorder, depression and anxiety; ii] the factors associated with mental health among those affected by floods; iii) the narratives associated with flooding, which focuses on the long-term impacts of flooding on mental health as a consequence of the secondary stressors; and iv) the management actions identified. The quantitative and qualitative studies have consistent findings. However, very few studies have used mixed methods to quantify the size of the mental health burden as well as exploration of in-depth narratives. Methodological limitations include control of potential confounders and short-term follow up. Limitations Floods following extreme events were excluded from our review. Conclusions Although the level of exposure to floods has been systematically associated with mental health problems, the paucity of longitudinal studies and lack of confounding controls precludes strong conclusions. Implications We recommend that future research in this area include mixed-method studies that are purposefully designed, using more rigorous methods. Studies should also focus on vulnerable groups and include analyses of policy and practical responses. PMID:25860572

Estimation of flood-frequency characteristics of small urban streams in North Carolina

USGS Publications Warehouse

Robbins, J.C.; Pope, B.F.

1996-01-01

A statewide study was conducted to develop methods for estimating the magnitude and frequency of floods of small urban streams in North Carolina. This type of information is critical in the design of bridges, culverts and water-control structures, establishment of flood-insurance rates and flood-plain regulation, and for other uses by urban planners and engineers. Concurrent records of rainfall and runoff data collected in small urban basins were used to calibrate rainfall-runoff models. Historic rain- fall records were used with the calibrated models to synthesize a long- term record of annual peak discharges. The synthesized record of annual peak discharges were used in a statistical analysis to determine flood- frequency distributions. These frequency distributions were used with distributions from previous investigations to develop a database for 32 small urban basins in the Blue Ridge-Piedmont, Sand Hills, and Coastal Plain hydrologic areas. The study basins ranged in size from 0.04 to 41.0 square miles. Data describing the size and shape of the basin, level of urban development, and climate and rural flood charac- teristics also were included in the database. Estimation equations were developed by relating flood-frequency char- acteristics to basin characteristics in a generalized least-squares regression analysis. The most significant basin characteristics are drainage area, impervious area, and rural flood discharge. The model error and prediction errors for the estimating equations were less than those for the national flood-frequency equations previously reported. Resulting equations, which have prediction errors generally less than 40 percent, can be used to estimate flood-peak discharges for 2-, 5-, 10-, 25-, 50-, and 100-year recurrence intervals for small urban basins across the State assuming negligible, sustainable, in- channel detention or basin storage.

Student-Designed River Study.

ERIC Educational Resources Information Center

Turkall, Sheila Florian

1996-01-01

Describes an integrated student-designed investigation in which students explore different aspects of the Chagrin River including the river ecosystem, velocity and average depth, river flooding, water quality, and economic and political factors. (JRH)

The application of the Contingent Valuation method towards the assessment of the impacts emerged from the March 2006 floods in the Evros River. An experts-based survey.

NASA Astrophysics Data System (ADS)

Markantonis, V.; Bithas, K.

2009-04-01

In March 2006 Greece was struck by a severe flooding, which caused significant damages in the Prefecture of Evros, on the Eastern border of Greece. 250 million m² of farmland was flooded causing severe damages to agriculture, transport and water supply networks. Total direct damages are estimated at € 372 million. The negative effect on economic activity caused by the floods, considered the worst over the last 50 years, took place in an area that had already been severely affected by floods in 2005. Apart from the direct damages critical were also the indirect impacts on the environmental and the social level. The need for economic analysis concerning the design and implementation of efficient flood management policies is well emphasized in the natural hazards' policies. Within this framework, the present paper is analyzing the application of stated preferences valuation techniques for the assessment of the damages caused in the Prefecture of Evros by the severe floods of March 2006. The objective of this paper is to define the role of economic valuation techniques in assisting the design of efficient and sustainable policies for flood management. More specific, the Contingent Valuation (CV) method is applied in order to valuate the impacts of the March 2006 floods, including the environmental impacts as far as concerns the soil, the biodiversity and the aesthetic environment of the flooded areas. The paper begins with a discussion of the theoretical economic framework, and particularly, the contingent valuation method framework that can be used to evaluate flood impacts. Understanding public preferences for complex environmental policy changes, such as flood impacts, is a preeminent challenge for environmental economists and other social scientists. Information issues are central to the design and application of the survey-based contingent valuation (CV) method for valuing environmental goods. While content is under the control of the analyst, how this information is accessed and used is ultimately up to the respondent. In addition, the future trends of floods in the Evros River Basin are presented, linking the socio-economic framework with the physical conditions of climate change. The forecast of the future precipitation trends in the Evros River has been realized at the Bjerkness Climate Change Center, Norway (May - July 2006). The objective of this forecast is to identify the future extreme precipitation trends in the Evros River Basin applying the global change models and identifying the differences between the present climate and the IPCC scenarios for the future climate. The scenario used for the present climate was the ‘20C3M' and the scenarios used for the future climate was the ‘SRES A2' and the ‘SRES A1B as well. The climate change models used were the following: BCM, ECHAM5_MPI, GFDL and CNRM_CM3. The analysis was based on changes concerning extreme precipitation in periods of three and seven days, which can theoritically lead to flooding events. Eventually, an application of the contingent valuation method is presented using the case study of March 2006 floods in the Evros River. In this context, the valuation scenario, the structure of the questionnaire, the elaboration of the survey and the results of the application are thoroughly illustrated. The good, or policy, being valued is the flooding impacts, focusing more at environmental aspects (soil, biodiversity, aesthetic environment). The survey includes a sample of 53 local experts in floods from various sectors such as local authorities, local public services, agricultural associations, environmental NGO's and universities. The survey is based on peer to peer interviews, which theoretically provide the most coherent results. The valuation question explores the Willingness to Pay (WTP) to Avoid future impacts of flooding formatted as an annual household fee and alternatively as a percentage of the Prefecture's GDP. In both cases the respondents are also asked which percentage of their initially stated value should specifically given for the elimination of the impacts on the soil, the biodiversity and the aesthetic environment. Moreover, the payment vehicle is the payment card method with four pre-defined sets of values. The basic survey template includes three major sections. The first part contains attitudinal, and knowledge questions. The second part, or valuation section, contains the contingent valuation scenario, the actual valuation questions and the follow-up questions. The final section contains the demographic questions. Results indicate well informed local experts who are willing to pay respectable amounts in order to avoid flooding impacts and give a strong gravity on the environmental impacts of the floods. Also, respondents are criticizing the weaknesses of the current flood management status and provide alternative policies, which can potentially affect the policy-making.

Quantifying invertebrate resistance to floods: a global-scale meta-analysis.

PubMed

McMullen, Laura E; Lytle, David A

2012-12-01

Floods are a key component of the ecology and management of riverine ecosystems around the globe, but it is not clear whether floods have predictable effects on organisms that can allow us to generalize across regions and continents. To address this, we conducted a global-scale meta-analysis to investigate effects of natural and managed floods on invertebrate resistance, the ability of invertebrates to survive flood events. We considered 994 studies for inclusion in the analysis, and after evaluation based on a priori criteria, narrowed our analysis to 41 studies spanning six of the seven continents. We used the natural-log-ratio of invertebrate abundance before and within 10 days after flood events because this measure of effect size can be directly converted to estimates of percent survival. We conducted categorical and continuous analyses that examined the contribution of environmental and study design variables to effect size heterogeneity, and examined differences in effect size among taxonomic groups. We found that invertebrate abundance was lowered by at least one-half after flood events. While natural vs. managed floods were similar in their effect, effect size differed among habitat and substrate types, with pools, sand, and boulders experiencing the strongest effect. Although sample sizes were not sufficient to examine all taxonomic groups, floods had a significant, negative effect on densities of Coleoptera, Eumalacostraca, Annelida, Ephemeroptera, Diptera, Plecoptera, and Trichoptera. Results from this study provide guidance for river flow regime prescriptions that will be applicable across continents and climate types, as well as baseline expectations for future empirical studies of freshwater disturbance.

Risk factors for injuries in landslide- and flood-affected populations in Uganda.

PubMed

Agrawal, Shreya; Gopalakrishnan, Tisha; Gorokhovich, Yuri; Doocy, Shannon

2013-08-01

The frequency of occurrence of natural disasters has increased over the past several decades, which necessitates a better understanding of human vulnerability, particularly in low-resource settings. This paper assesses risk factors for injury in the March 2010 floods and landslides in Eastern Uganda, and compares the effects of location, injury type, and severity. A stratified cluster survey of the disaster-affected populations was conducted five months after onset of the disasters. Probability proportional to size sampling was used to sample 800 households, including 400 affected by floods in Butaleja District and 400 affected by landslides in Bududa District. Flood- and landslide-affected populations were surveyed in July 2010 using a stratified cluster design. The odds of injury were 65% higher in the flood-affected groups than the landslide-affected groups in a logistic regression (OR = 0.35; 95% CI, 0.24-0.52; P < .001). The injury rate was greater in individuals under 42 years of age, and location of injury was a contributing factor. More people were injured in the flood-affected population as compared with the landslide-affected population, and injuries were more severe. This study illustrates differences between populations injured by flood and landslide disasters that occurred simultaneously in Eastern Uganda in 2010. In areas where landslides are prone to occur due to massive rainfalls or floods, preventative measures, such as early warning systems and evacuation, are more likely to increase the likelihood of people surviving, while for areas with massive floods, immediate and effective medical attention can save lives and improve injury outcomes.

Projections of Flood Risk using Credible Climate Signals in the Ohio River Basin

NASA Astrophysics Data System (ADS)

Schlef, K.; Robertson, A. W.; Brown, C.

2017-12-01

Estimating future hydrologic flood risk under non-stationary climate is a key challenge to the design of long-term water resources infrastructure and flood management strategies. In this work, we demonstrate how projections of large-scale climate patterns can be credibly used to create projections of long-term flood risk. Our study area is the northwest region of the Ohio River Basin in the United States Midwest. In the region, three major teleconnections have been previously demonstrated to affect synoptic patterns that influence extreme precipitation and streamflow: the El Nino Southern Oscillation, the Pacific North American pattern, and the Pacific Decadal Oscillation. These teleconnections are strongest during the winter season (January-March), which also experiences the greatest number of peak flow events. For this reason, flood events are defined as the maximum daily streamflow to occur in the winter season. For each gage in the region, the location parameter of a log Pearson type 3 distribution is conditioned on the first principal component of the three teleconnections to create a statistical model of flood events. Future projections of flood risk are created by forcing the statistical model with projections of the teleconnections from general circulation models selected for skill. We compare the results of our method to the results of two other methods: the traditional model chain (i.e., general circulation model projections to downscaling method to hydrologic model to flood frequency analysis) and that of using the historic trend. We also discuss the potential for developing credible projections of flood events for the continental United States.

Impact of the proposed I-326 crossing on the 500-year flood stages of the Congaree River near Columbia, South Carolina

USGS Publications Warehouse

Bennett, C.S.

1984-01-01

A two-dimensional finite-element surface water flow modeling system based on the shallow water equations was used to study the hydraulic impact of the proposed Interstate crossing on the 500-year flood. Infrared aerial photography was used to define regions of homogeneous roughness in the flood plain. Finite-element networks approximating flood plain topography were designed using elements of three roughness types. High water marks established during an 8-year flood that occurred in October 1976 were used to calibrate the model. The 500-year flood (630,000 cu ft/sec) was simulated using the dike on the left bank as the left boundary and the right edge of the flood plain as the right boundary. Simulations were performed without and with the proposed highway embankments in place. Detailed information was obtained about backwater effects upstream from the proposed highway embankments, changes in flow distribution resulting from embankments, and velocities in the vicinity of the bridge openings. The results of the study indicate that the four bridge openings in the right flood plain should be adequate to handle the 500-yr flood flow. Forty percent of the flow passes through the main channel bridge, while the remaining 60% of the flow passes through the three overflow bridges. Average velocities in the bridge openings ranged from 3.4 ft/sec to 6.9 ft/sec with a maximum vertically averaged velocity of 9.3 ft/sec occurring at the right edge of one of the overflow bridges. (Author 's abstract)

Cell design concepts for aqueous lithium-oxygen batteries: A model-based assessment

NASA Astrophysics Data System (ADS)

Grübl, Daniel; Bessler, Wolfgang G.

2015-11-01

Seven cell design concepts for aqueous (alkaline) lithium-oxygen batteries are investigated using a multi-physics continuum model for predicting cell behavior and performance in terms of the specific energy and specific power. Two different silver-based cathode designs (a gas diffusion electrode and a flooded cathode) and three different separator designs (a porous separator, a stirred separator chamber, and a redox-flow separator) are compared. Cathode and separator thicknesses are varied over a wide range (50 μm-20 mm) in order to identify optimum configurations. All designs show a considerable capacity-rate effect due to spatiotemporally inhomogeneous precipitation of solid discharge product LiOH·H2O. In addition, a cell design with flooded cathode and redox-flow separator including oxygen uptake within the external tank is suggested. For this design, the model predicts specific power up to 33 W/kg and specific energy up to 570 Wh/kg (gravimetric values of discharged cell including all cell components and catholyte except housing and piping).

Game Theory and Risk-Based Levee System Design

NASA Astrophysics Data System (ADS)

Hui, R.; Lund, J. R.; Madani, K.

2014-12-01

Risk-based analysis has been developed for optimal levee design for economic efficiency. Along many rivers, two levees on opposite riverbanks act as a simple levee system. Being rational and self-interested, land owners on each river bank would tend to independently optimize their levees with risk-based analysis, resulting in a Pareto-inefficient levee system design from the social planner's perspective. Game theory is applied in this study to analyze decision making process in a simple levee system in which the land owners on each river bank develop their design strategies using risk-based economic optimization. For each land owner, the annual expected total cost includes expected annual damage cost and annualized construction cost. The non-cooperative Nash equilibrium is identified and compared to the social planner's optimal distribution of flood risk and damage cost throughout the system which results in the minimum total flood cost for the system. The social planner's optimal solution is not feasible without appropriate level of compensation for the transferred flood risk to guarantee and improve conditions for all parties. Therefore, cooperative game theory is then employed to develop an economically optimal design that can be implemented in practice. By examining the game in the reversible and irreversible decision making modes, the cost of decision making myopia is calculated to underline the significance of considering the externalities and evolution path of dynamic water resource problems for optimal decision making.

Design and Development of a Segmented Magnet Homopolar Torque Converter

DTIC Science & Technology

1975-07-01

configuration Hydrostatically-positioned seal ( sealed drain) Hydrostatically-positioned seal Power- leakage relationship for a single annular seal lip... Seal 1. conducting wick - stationary/rotating, fiber, foam 2. hydrodynamic/hydrostatic 3. flooded (alternately) labyrinth C. Low-Speed Flooding...between collectors may be used to introduce oil droplets to lubricate the seals and to drain any NaK leakage that might occur Alternatively, they

Short-term impacts of floods on enteric infectious disease in Qingdao, China, 2005-2011.

PubMed

Zhang, F; Liu, Z; Gao, L; Zhang, C; Jiang, B

2016-11-01

The current study aimed to examine the relationship between floods and the three enteric infectious diseases, namely bacillary dysentery (BD), hand-foot-mouth disease (HFMD) and other infectious diarrhoea (OID) in Qingdao, China. Relative risks (RRs) and 95% confidence intervals (CIs) of floods on BD, HFMD and OID were calculated using a quasi-Poisson generalized linear model, adjusting for daily average temperature, daily average relative humidity, and seasonal and long-term temporal trends. Two separate models within two different periods were designed. Model 1 for the summer period showed that floods were positively associated with BD for 4- to 12-day lags, with the greatest effects for 7-day (RR 1·41, 95% CI 1·22-1·62) and 11-day (RR 1·42, 95% CI 1·22-1·64) lags. Similar findings were found in model 2 for the whole study period for 5- to 12-day lags. However, HFMD and OID were not significantly associated with floods in both models. Results from this study will provide insight into the health risks associated with floods and may help inform public health precautionary measures for such disasters.

An improved database of coastal flooding in the United Kingdom from 1915 to 2016

PubMed Central

Haigh, Ivan D.; Ozsoy, Ozgun; Wadey, Matthew P.; Nicholls, Robert J.; Gallop, Shari L.; Wahl, Thomas; Brown, Jennifer M.

2017-01-01

Coastal flooding caused by extreme sea levels can produce devastating and wide-ranging consequences. The ‘SurgeWatch’ v1.0 database systematically documents and assesses the consequences of historical coastal flood events around the UK. The original database was inevitably biased due to the inconsistent spatial and temporal coverage of sea-level observations utilised. Therefore, we present an improved version integrating a variety of ‘soft’ data such as journal papers, newspapers, weather reports, and social media. SurgeWatch2.0 identifies 329 coastal flooding events from 1915 to 2016, a more than fivefold increase compared to the 59 events in v1.0. Moreover, each flood event is now ranked using a multi-level categorisation based on inundation, transport disruption, costs, and fatalities: from 1 (Nuisance) to 6 (Disaster). For the 53 most severe events ranked Category 3 and above, an accompanying event description based upon the Source-Pathway-Receptor-Consequence framework was produced. Thus, SurgeWatch v2.0 provides the most comprehensive and coherent historical record of UK coastal flooding. It is designed to be a resource for research, planning, management and education. PMID:28763054

Evaluating changes to reservoir rule curves using historical water-level data

USGS Publications Warehouse

Mower, Ethan; Miranda, Leandro E.

2013-01-01

Flood control reservoirs are typically managed through rule curves (i.e. target water levels) which control the storage and release timing of flood waters. Changes to rule curves are often contemplated and requested by various user groups and management agencies with no information available about the actual flood risk of such requests. Methods of estimating flood risk in reservoirs are not easily available to those unfamiliar with hydrological models that track water movement through a river basin. We developed a quantile regression model that uses readily available daily water-level data to estimate risk of spilling. Our model provided a relatively simple process for estimating the maximum applicable water level under a specific flood risk for any day of the year. This water level represents an upper-limit umbrella under which water levels can be operated in a variety of ways. Our model allows the visualization of water-level management under a user-specified flood risk and provides a framework for incorporating the effect of a changing environment on water-level management in reservoirs, but is not designed to replace existing hydrological models. The model can improve communication and collaboration among agencies responsible for managing natural resources dependent on reservoir water levels.

Agricultural damages and losses from ARkStorm scenario flooding in California

USGS Publications Warehouse

Wein, Anne; David Mitchell,; Peters, Jeff; John Rowden,; Johnny Tran,; Alessandra Corsi,; Dinitz, Laura B.

2016-01-01

Scientists designed the ARkStorm scenario to challenge the preparedness of California communities for widespread flooding with a historical precedence and increased likelihood under climate change. California is an important provider of vegetables, fruits, nuts, and other agricultural products to the nation. This study analyzes the agricultural damages and losses pertaining to annual crops, perennial crops, and livestock in California exposed to ARkStorm flooding. Statewide, flood damage is incurred on approximately 23% of annual crop acreage, 5% of perennial crop acreage, and 5% of livestock, e.g., dairy, feedlot, and poultry, acreage. The sum of field repair costs, forgone income, and product replacement costs span $3.7 and $7.1 billion (2009) for a range of inundation durations. Perennial crop loss estimates dominate, and the vulnerability of orchards and vineyards has likely increased with recent expansion. Crop reestablishment delays from levee repair and dewatering more than double annual crop losses in the delta islands, assuming the fragile system does not remain permanently flooded. The exposure of almost 200,000 dairy cows to ARkStorm flooding poses livestock evacuation challenges. Read More: http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29NH.1527-6996.0000174

An assessment of flood mitigation measures - "room for the river

NASA Astrophysics Data System (ADS)

Komma, J.; Blöschl, G.; Habereder, C.

2009-04-01

In this paper we analyse the relative effect of different flood mitigation measures for the example of the Kamp catchment in Austria. The main idea is to decrease flood peaks through (a) retaining water in the landscape and (b) providing additional inundation areas along the main stream (room for the river). To increase the retention of excess rainfall in the landscape we introduced two different measures. One measure is the increase of water storage capacity in the study catchment through the change of land use from agriculture to forest. The second measure is the installation of many small sized retention basins without an outlet (micro ponds). The micro ponds are situated at the hill slopes to intercept surface runoff. In case of the room for the river scenario the additional retention volume is gained due to the installation of retention basins along the Kamp river and its tributary Zwettl. Three flood retention basins with culverts at each river are envisaged. The geometry of the bottom outlets is defined for design discharges in a way to gain the greatest flood peak reduction for large flood events (above a 100 yr flood). The study catchment at the Kamp river with a size of 622 km² is located in north-eastern Austria. For the simulation of the different scenarios (retaining water in the landscape) a well calibrated continuous hydrologic model is available. The hydrological model consists of a spatially distributed soil moisture accounting scheme and a flood routing component. To analyse the effect of the room for the river scenario with retention basins along the river reaches a linked 1D/2D hydrodynamic model (TUFLOW) is used. In the river channels a one dimensional simulation is carried out. The flow conditions in the flood plains are represented by two dimensional model elements. The model domain incorporates 18 km of the Kamp and 12 km of the Zwettl river valley. For the assessment of the land use change scenario the hydrologic model parameters for wooded areas are transferred to areas that are currently not forested. Through higher storage capacities in the wooded areas the scenario of afforestation helps to reduce flood peaks. The micro ponds are represented in the hydrological model by a bucket storage component. It is filled by a fraction of the simulated direct runoff and drains into the groundwater with a constant percolation rate. For the scenarios of flood mitigation with retention basins along the river reaches three locations at the Kamp and three locations at the Zwettl river have been chosen for hypothetical retention basins or polders with bottom outlets. The main difference between the "room for the river" method and the "retaining water in the landscape" methods is the magnitude of the flood event for which the retention is maximised. For the case of retaining water in the landscape (either by land use change or microponds) the storage capacity obtained by these measures is filled at the beginning of the event. For small event magnitudes, the flood peak reduction is hence maximised. In the Kamp catchment, significant reductions in the flood peaks can be obtained when retention basins along the main stream are constructed and the flood plains are inundated. The main advantage of the room for the river methodology is that the polders/retention basins can be designed in a way that there is no retention for small flood discharges which leaves the full storage capacity for larger floods at the time of peak. In contrast, for the retaining water in the landscape measures, the storage is exhausted at an early stage of medium and large events, resulting in very small flood peak reductions.

Annual peak discharges from small drainage areas in Montana through September 1976

USGS Publications Warehouse

Johnson, M.V.; Omang, R.J.; Hull, J.A.

1977-01-01

Annual peak discharge from small drainage areas is tabulated for 336 sites in Montana. The 1976 additions included data collected at 206 sites. The program which investigates the magnitude and frequency of floods from small drainage areas in Montana, was begun July 1, 1955. Originally 45 crest-stage gaging stations were established. The purpose of the program is to collect sufficient peak-flow data, which through analysis could provide methods for estimating the magnitude and frequency of floods at any point in Montana. The ultimate objective is to provide methods for estimating the 100-year flood with the reliability needed for road design. (Woodard-USGS)

Simulation of wetlands forest vegetation dynamics

USGS Publications Warehouse

Phipps, R.L.

1979-01-01

A computer program, SWAMP, was designed to simulate the effects of flood frequency and depth to water table on southern wetlands forest vegetation dynamics. By incorporating these hydrologic characteristics into the model, forest vegetation and vegetation dynamics can be simulated. The model, based on data from the White River National Wildlife Refuge near De Witt, Arkansas, "grows" individual trees on a 20 x 20-m plot taking into account effects on the tree growth of flooding, depth to water table, shade tolerance, overtopping and crowding, and probability of death and reproduction. A potential application of the model is illustrated with simulations of tree fruit production following flood-control implementation and lumbering. ?? 1979.

Design for Resilience in Brattleboro's Lower Whetstone Brook Corridor

EPA Pesticide Factsheets

This report details design solutions that identify options for creating resilient redevelopment & recreational opportunities within flood prone areas of the town while protecting water quality & connecting people with the Whetstone Brook.

A framework to support decision making in the selection of sustainable drainage system design alternatives.

PubMed

Wang, Mingming; Sweetapple, Chris; Fu, Guangtao; Farmani, Raziyeh; Butler, David

2017-10-01

This paper presents a new framework for decision making in sustainable drainage system (SuDS) scheme design. It integrates resilience, hydraulic performance, pollution control, rainwater usage, energy analysis, greenhouse gas (GHG) emissions and costs, and has 12 indicators. The multi-criteria analysis methods of entropy weight and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) were selected to support SuDS scheme selection. The effectiveness of the framework is demonstrated with a SuDS case in China. Indicators used include flood volume, flood duration, a hydraulic performance indicator, cost and resilience. Resilience is an important design consideration, and it supports scheme selection in the case study. The proposed framework will help a decision maker to choose an appropriate design scheme for implementation without subjectivity. Copyright © 2017 Elsevier Ltd. All rights reserved.

What are people thinking about floods? A study in two Mediterranean areas: Costa Brava, Spain and Talcahuano City, Chile

NASA Astrophysics Data System (ADS)

Lara, A.; Ribas, A.; Cifuentes, L. A.

2013-05-01

Mediterranean areas are not immune to flood problems. The Spanish Mediterranean coast is a reflection of this, where flooding continues to be the greatest natural hazard with negative effects on the territory. The urbanization of coastal watersheds, very pronounced in the last 15 years, has led to the creation of authentic urban continuums in the seafront and the appearance of residential developments therein. The municipalities of Costa Brava, in the province of Girona, are an example of this dynamic of the increasing risk, exposure, and impact of floods. In Chile, floods are considered one of the main natural hazards, especially in the province of Concepcion. One of the most important cities of this area is Talcahuano, which has suffered continual flood episodes during recent years. Flood episodes could yet increase in the future due to the high frequency of extraordinary atmospheric events and a higher exposure to flood risk created by the development of intensive urbanization processes. However, after the February 27th 8.8 degrees earthquake (Richter scale) that affected the center-south of Chile and originated the tsunami which flooded a large percentage of the residential area and military base of the city of Talcahuano, the risk, vulnerability, resilience and copy capacity concepts changed. This research looks at the social perception and social knowledge of Mediterranean residents affected and unaffected by floods, emphasizing which is their risk, vulnerability, resilience and copy capacity concept and what kind of measures they proposed to reduce their flood vulnerability. The end objective of this research is to become a framework for future local flood policies and a tool that could be reviewed by specialists in other regions that might be affected by this hazard. This social assessment has been carried out through surveys of residents in Costa Brava and Talcahuano whose endogenous and exogenous characteristics have been significant in explaining their perceptions. The main results show that: a) the flood experience is a determinant in social perception of flood risk; b) fear has a strong role in the livelihood of Talcahuano residents; c) Insurance is the main solution for Spanish residents; d) the residents surveyed feel that the government and disaster managers ignore the local community for design measures to improve local vulnerability against floods and; e) both areas give strong support to implementing structural measures.

Geospatial Analysis for Flood-Risk Management, Resilience, and US Policy

NASA Astrophysics Data System (ADS)

Pinter, N.; Hui, R.; Conrad, D. R.; Schaefer, K.

2016-12-01

The National Flood Insurance Program (NFIP) was established in 1968 to curtail unfettered development on US floodplains and spiraling taxpayer expenditures for disaster relief. Currently NFIP underwrites >5 million policies, providing >1.25 trillion in coverage, and taking in >3.5 billion in annual premiums. Cumulative flood-damage payouts to date exceed premiums collected by >$20 billion. Our group has obtained nationwide databases of NFIP flood-damage claims back to 1972, annual policies since 1994, and selective Federal Emergency Management Agency (FEMA) repetitive losses. Attributes include property, claims, and loss characteristics. Other attributes were stripped to maintain policyholder anonymity. At present, locations are to the nearest 0.1° lat/long, zip code, and by community. We combine NFIP data with GIS information from a variety of other sources. Over the past 44 years, 1,625,470 non-zero flood claims are documented. Numbers of claims and losses have increased over time, even with extreme events (Hurricanes Katrina and Sandy) excluded. Flood losses have occurred within 100-year floodplains (1% annual exceedance), in coastal hazard zones, and 25% of claims occur outside of mapped flood-hazard areas. We hypothesize that a many losses outside of FEMA's designated Special Flood Hazard Area (SFHA) correlate with (1) outdated map panels, (2) contrasting levels of enforcement and mitigation by state. Other distributed flood losses represent stormwater/drainage damage. Claim rates substantially exceed 1%, both in and outside the SFHA, and for "pre-FIRM" and "post-FIRM" structures. This suggests that ≥100-year floods are occurring more frequently than statutory frequencies suggest. For US homeowners, this suggests that flood insurance is a good deal in a variety of settings. The NFIP data analyzed here contrasts with our group's previous, largely model-driven research. Such empirical flood data exclude model assumptions, but add dizzying array of human and political factors into the resulting spatial and temporal patterns. Parsing out the hydrologic, climatic, social, and political factors influencing flood risk and resilience is crucial for sound management of NFIP and other programs. The US Congress will debate reauthorization and possible revision of NFIP in 2017.

Regional interdisciplinary paleoflood approach to assess extreme flood potential

USGS Publications Warehouse

Jarrett, Robert D.; Tomlinson, Edward M.

2000-01-01

In the past decade, there has been a growing interest of dam safety officials to incorporate a risk‐based analysis for design‐flood hydrology. Extreme or rare floods, with probabilities in the range of about 10−3 to 10−7 chance of occurrence per year, are of continuing interest to the hydrologic and engineering communities for purposes of planning and design of structures such as dams [National Research Council, 1988]. The National Research Council stresses that as much information as possible about floods needs to be used for evaluation of the risk and consequences of any decision. A regional interdisciplinary paleoflood approach was developed to assist dam safety officials and floodplain managers in their assessments of the risk of large floods. The interdisciplinary components included documenting maximum paleofloods and a regional analyses of contemporary extreme rainfall and flood data to complement a site‐specific probable maximum precipitation study [Tomlinson and Solak, 1997]. The cost‐effective approach, which can be used in many other hydrometeorologic settings, was applied to Elkhead Reservoir in Elkhead Creek (531 km2) in northwestern Colorado; the regional study area was 10,900 km2. Paleoflood data using bouldery flood deposits and noninundation surfaces for 88 streams were used to document maximum flood discharges that have occurred during the Holocene. Several relative dating methods were used to determine the age of paleoflood deposits and noninundation surfaces. No evidence of substantial flooding was found in the study area. The maximum paleoflood of 135 m3 s−1 for Elkhead Creek is about 13% of the site‐specific probable maximum flood of 1020 m3 s−1. Flood‐frequency relations using the expected moments algorithm, which better incorporates paleoflood data, were developed to assess the risk of extreme floods. Envelope curves encompassing maximum rainfall (181 sites) and floods (218 sites) were developed for northwestern Colorado to help define maximum contemporary and Holocene flooding in Elkhead Creek and in a regional frequency context. Study results for Elkhead Reservoir were accepted by the Colorado State Engineer for dam safety certification.

Can we (actually) assess global risk?

NASA Astrophysics Data System (ADS)

Di Baldassarre, Giuliano

2013-04-01

The evaluation of the dynamic interactions of the different components of global risk (e.g. hazard, exposure, vulnerability or resilience) is one of the main challenges in risk assessment and management. In state-of-the-art approaches for the analysis of risk, natural and socio-economic systems are typically treated separately by using different methods. In flood risk studies, for instance, physical scientists typically focus on the study of the probability of flooding (i.e. hazard), while social scientists mainly examine the exposure, vulnerability or resilience to flooding. However, these different components are deeply interconnected. Changes in flood hazard might trigger changes in vulnerability, and vice versa. A typical example of these interactions is the so-called "levee effect", whereby heightening levees to reduce the probability of flooding often leads to increase the potential adverse consequences of flooding as people often perceive that flood risk was completely eliminated once the levee was raised. These interconnections between the different components of risk remain largely unexplored and poorly understood. This lack of knowledge is of serious concern as it limits our ability to plan appropriate risk prevention measures. To design flood control structures, for example, state-of-the-art models can indeed provide quantitative assessments of the corresponding risk reduction associated to the lower probability of flooding. Nevertheless, current methods cannot estimate how, and to what extent, such a reduction might trigger a future increase of the potential adverse consequences of flooding (the aforementioned "levee effect"). Neither can they evaluate how the latter might (in turn) lead to the requirement of additional flood control structures. Thus, while many progresses have been made in the static assessment of flood risk, more inter-disciplinary research is required for the development of methods for dynamic risk assessment, which is very much needed in a rapidly changing world. This presentation will discuss these challenges and describe a few initial attempts aiming to better understand the interactions between the different components of flood risk with reference to diverse case studies in Europe, Central America, and Africa.

Voice-enabled Knowledge Engine using Flood Ontology and Natural Language Processing

NASA Astrophysics Data System (ADS)

Sermet, M. Y.; Demir, I.; Krajewski, W. F.

2015-12-01

The Iowa Flood Information System (IFIS) is a web-based platform developed by the Iowa Flood Center (IFC) to provide access to flood inundation maps, real-time flood conditions, flood forecasts, flood-related data, information and interactive visualizations for communities in Iowa. The IFIS is designed for use by general public, often people with no domain knowledge and limited general science background. To improve effective communication with such audience, we have introduced a voice-enabled knowledge engine on flood related issues in IFIS. Instead of navigating within many features and interfaces of the information system and web-based sources, the system provides dynamic computations based on a collection of built-in data, analysis, and methods. The IFIS Knowledge Engine connects to real-time stream gauges, in-house data sources, analysis and visualization tools to answer natural language questions. Our goal is the systematization of data and modeling results on flood related issues in Iowa, and to provide an interface for definitive answers to factual queries. The goal of the knowledge engine is to make all flood related knowledge in Iowa easily accessible to everyone, and support voice-enabled natural language input. We aim to integrate and curate all flood related data, implement analytical and visualization tools, and make it possible to compute answers from questions. The IFIS explicitly implements analytical methods and models, as algorithms, and curates all flood related data and resources so that all these resources are computable. The IFIS Knowledge Engine computes the answer by deriving it from its computational knowledge base. The knowledge engine processes the statement, access data warehouse, run complex database queries on the server-side and return outputs in various formats. This presentation provides an overview of IFIS Knowledge Engine, its unique information interface and functionality as an educational tool, and discusses the future plans for providing knowledge on flood related issues and resources. IFIS Knowledge Engine provides an alternative access method to these comprehensive set of tools and data resources available in IFIS. Current implementation of the system accepts free-form input and voice recognition capabilities within browser and mobile applications.

Development of method for evaluating estimated inundation area by using river flood analysis based on multiple flood scenarios

NASA Astrophysics Data System (ADS)

Ono, T.; Takahashi, T.

2017-12-01

Non-structural mitigation measures such as flood hazard map based on estimated inundation area have been more important because heavy rains exceeding the design rainfall frequently occur in recent years. However, conventional method may lead to an underestimation of the area because assumed locations of dike breach in river flood analysis are limited to the cases exceeding the high-water level. The objective of this study is to consider the uncertainty of estimated inundation area with difference of the location of dike breach in river flood analysis. This study proposed multiple flood scenarios which can set automatically multiple locations of dike breach in river flood analysis. The major premise of adopting this method is not to be able to predict the location of dike breach correctly. The proposed method utilized interval of dike breach which is distance of dike breaches placed next to each other. That is, multiple locations of dike breach were set every interval of dike breach. The 2D shallow water equations was adopted as the governing equation of river flood analysis, and the leap-frog scheme with staggered grid was used. The river flood analysis was verified by applying for the 2015 Kinugawa river flooding, and the proposed multiple flood scenarios was applied for the Akutagawa river in Takatsuki city. As the result of computation in the Akutagawa river, a comparison with each computed maximum inundation depth of dike breaches placed next to each other proved that the proposed method enabled to prevent underestimation of estimated inundation area. Further, the analyses on spatial distribution of inundation class and maximum inundation depth in each of the measurement points also proved that the optimum interval of dike breach which can evaluate the maximum inundation area using the minimum assumed locations of dike breach. In brief, this study found the optimum interval of dike breach in the Akutagawa river, which enabled estimated maximum inundation area to predict efficiently and accurately. The river flood analysis by using this proposed method will contribute to mitigate flood disaster by improving the accuracy of estimated inundation area.

Evaluation of green infrastructure designs using the Automated Geospatial Watershed Assessment Tool

USDA-ARS?s Scientific Manuscript database

In arid and semi-arid regions, green infrastructure (GI) designs can address several issues facing urban environments, including augmenting water supply, mitigating flooding, decreasing pollutant loads, and promoting greenness in the built environment. An optimum design captures stormwater, addressi...

Control And Containment Design Report

EPA Pesticide Factsheets

his work plan (571-pages) is called the “SWMU-3-1 and 3-4 Control and Containment Design Report” was written to be in compliance with new FEMA requirements that the design must not create any positive change in the 100 year flood elevation.

Flood Impact Assessment in the Surrounding Area of Suvarnabhumi Airport, Thailand

NASA Astrophysics Data System (ADS)

Tingsanchali, Tawatchai; Eng, D.

2009-03-01

The existence of the Second Bangkok International Airport (SBIA) or the Suvarnabhumi International Airport induces more adverse effect to the flooding situation in its surrounding area. Due to limited drainage capacity, during a heavy storm, flooding in the surrounding area occurs over the area. The objective of the study is to find the most suitable flood control and drainage system that can drain floodwater from the surrounding area of 624 sq. km with minimum flood damages and impact to social and living conditions of the people in the study area. This study involves the application of MIKE FLOOD hydrodynamic model for determining the relative effects of flood control and drainage system in the surrounding area of the airport. The results of the study show that flood damages mostly occur in the central and downstream parts of the study area where drainage is insufficient. Flood depth and duration are main parameters used for the estimation of flood losses. Flood mitigation and management in the surrounding area of SBIA is planned by pumping water of 100 m3/s from Klong Samrong canal inside the study area through the proposed drainage channel to the Gulf of Thailand. The existing dikes along boundaries of the study area can protect water from the outer area to enter into the surrounding area of the airport. Flood simulation shows that a canal with capacity of 100 m3/s and a pumping station at the downstream end of the canal are required to cope with the drainage capacity for the flood of 100 years return period. A flood drainage channel of capacity of 100 m3/s is designed and will be constructed to drain flood from Klong Samrong to the sea. On the other hand, the embankment along the proposed drainage canal project improves traffic flow in the vicinity of the airport. On economic benefit, the project investment cost is Baht 8,410 million. The project benefit cost ratio is 2.12 with the economic internal rate of return of 15.61%. The construction period is 4 years. Environmental and social impacts are investigated and counter measures are proposed to reduce the impacts. The study considers compensating scheme for people who are directly affected by the flood drainage project and those who will lose their lands or their professions. Considerations are also extended to people who are indirectly affected by the project. Institutional framework is recommended to be established to manage flood control and drainage and water resources in the surrounding area of the airport.

Evaluating the placement and performance of nature based measures for managing flood runoff in intensively farmed landscapes

NASA Astrophysics Data System (ADS)

Wilkinson, Mark; Quinn, Paul; Hewett, Caspar; Stutter, Marc

2017-04-01

Over the past decade economic losses from fluvial floods have greatly increased and it is becoming less viable to use traditional measures for managing flooding solely. This has given rise to increasing interest in alternative, nature based solutions (NBS) for reducing flood risk that aim to manage runoff at the catchment source and deliver multiple benefits. In many cases these measures need to work with current agricultural practices. Intensive agriculture often results in increases in local runoff rates, water quality issues, soil erosion/loss and local flooding problems. However, there is potential for agriculture to play a part in reducing flood risk. This requires knowledge on the effectiveness of NBS at varying scales and tools to communicate the risk of runoff associated with farming. This paper assesses the placement, management and effectiveness of a selection of nature-based measures in the rural landscape. Measures which disconnect overland flow pathways and improve soil infiltration are discussed. Case study examples are presented from the UK where a large number of nature-based measures have been constructed as part of flood protection schemes in catchment scales varying from 50 ha to 25 km2. Practical tools to help locate measures in agricultural landscapes are highlighted including the Floods and Agriculture Risk Matrix (FARM), an interactive communication/visualization tool and FARMPLOT, a GIS mapping tool. These have been used to promote such measures, by showing how and where temporary ponded areas can be located to reduce flood and erosion risk whilst minimising disruption to farming practices. In most cases land managers prefer small ( 100-1000m3) temporary ponding areas which fill during moderate to large storm events since they incur minimal loss of land. They also provide greater resillience to multi-day storm events, as they are designed to drain over 1-2 days and therefore allow for storage capacity for proceeding events. However, the performance of isolated temporary storage areas can be limited during extreme events. At larger scales taking a treatment train approach using a network of measures has been shown to achieve greater benefits, e.g. by reducing local flood peaks and capturing sediments. Current local scale evidence presented here has been used to inform environmental policy on the correct placement and design of flood reduction measures. Further long term data collection is required to assess the larger scale impact of these measures. These data can be used to inform scenario-based modelling approaches. By holding and attenuating runoff in rural landscapes, benefits for local flood peak reduction, water quality improvement and sediment management can be achieved. However, there is still a need to examine the sustainability of such measures through long term environmental payment schemes, considering how they could be funded across generational timescales rather than political cycles, and to monitor these measures over longer timescales and in multiple settings.

A framework for multivariate data-based at-site flood frequency analysis: Essentiality of the conjugal application of parametric and nonparametric approaches

NASA Astrophysics Data System (ADS)

Vittal, H.; Singh, Jitendra; Kumar, Pankaj; Karmakar, Subhankar

2015-06-01

In watershed management, flood frequency analysis (FFA) is performed to quantify the risk of flooding at different spatial locations and also to provide guidelines for determining the design periods of flood control structures. The traditional FFA was extensively performed by considering univariate scenario for both at-site and regional estimation of return periods. However, due to inherent mutual dependence of the flood variables or characteristics [i.e., peak flow (P), flood volume (V) and flood duration (D), which are random in nature], analysis has been further extended to multivariate scenario, with some restrictive assumptions. To overcome the assumption of same family of marginal density function for all flood variables, the concept of copula has been introduced. Although, the advancement from univariate to multivariate analyses drew formidable attention to the FFA research community, the basic limitation was that the analyses were performed with the implementation of only parametric family of distributions. The aim of the current study is to emphasize the importance of nonparametric approaches in the field of multivariate FFA; however, the nonparametric distribution may not always be a good-fit and capable of replacing well-implemented multivariate parametric and multivariate copula-based applications. Nevertheless, the potential of obtaining best-fit using nonparametric distributions might be improved because such distributions reproduce the sample's characteristics, resulting in more accurate estimations of the multivariate return period. Hence, the current study shows the importance of conjugating multivariate nonparametric approach with multivariate parametric and copula-based approaches, thereby results in a comprehensive framework for complete at-site FFA. Although the proposed framework is designed for at-site FFA, this approach can also be applied to regional FFA because regional estimations ideally include at-site estimations. The framework is based on the following steps: (i) comprehensive trend analysis to assess nonstationarity in the observed data; (ii) selection of the best-fit univariate marginal distribution with a comprehensive set of parametric and nonparametric distributions for the flood variables; (iii) multivariate frequency analyses with parametric, copula-based and nonparametric approaches; and (iv) estimation of joint and various conditional return periods. The proposed framework for frequency analysis is demonstrated using 110 years of observed data from Allegheny River at Salamanca, New York, USA. The results show that for both univariate and multivariate cases, the nonparametric Gaussian kernel provides the best estimate. Further, we perform FFA for twenty major rivers over continental USA, which shows for seven rivers, all the flood variables followed nonparametric Gaussian kernel; whereas for other rivers, parametric distributions provide the best-fit either for one or two flood variables. Thus the summary of results shows that the nonparametric method cannot substitute the parametric and copula-based approaches, but should be considered during any at-site FFA to provide the broadest choices for best estimation of the flood return periods.

Characterization of flood and precipitation events in Southwestern Germany and stochastic simulation of extreme precipitation (Project FLORIS-SV)

NASA Astrophysics Data System (ADS)

Florian, Ehmele; Michael, Kunz

2016-04-01

Several major flood events occurred in Germany in the past 15-20 years especially in the eastern parts along the rivers Elbe and Danube. Examples include the major floods of 2002 and 2013 with an estimated loss of about 2 billion Euros each. The last major flood events in the State of Baden-Württemberg in southwest Germany occurred in the years 1978 and 1993/1994 along the rivers Rhine and Neckar with an estimated total loss of about 150 million Euros (converted) each. Flood hazard originates from a combination of different meteorological, hydrological and hydraulic processes. Currently there is no defined methodology available for evaluating and quantifying the flood hazard and related risk for larger areas or whole river catchments instead of single gauges. In order to estimate the probable maximum loss for higher return periods (e.g. 200 years, PML200), a stochastic model approach is designed since observational data are limited in time and space. In our approach, precipitation is linearly composed of three elements: background precipitation, orographically-induces precipitation, and a convectively-driven part. We use linear theory of orographic precipitation formation for the stochastic precipitation model (SPM), which is based on fundamental statistics of relevant atmospheric variables. For an adequate number of historic flood events, the corresponding atmospheric conditions and parameters are determined in order to calculate a probability density function (pdf) for each variable. This method involves all theoretically possible scenarios which may not have happened, yet. This work is part of the FLORIS-SV (FLOod RISk Sparkassen Versicherung) project and establishes the first step of a complete modelling chain of the flood risk. On the basis of the generated stochastic precipitation event set, hydrological and hydraulic simulations will be performed to estimate discharge and water level. The resulting stochastic flood event set will be used to quantify the flood risk and to estimate probable maximum loss (e.g. PML200) for a given property (buildings, industry) portfolio.

Assessing Flood Risk at Nuclear Power Plants with an Uncertain Climate

NASA Astrophysics Data System (ADS)

Wigmosta, M. S.; Vail, L. W.

2011-12-01

In 2010 a tsunami severely damaged the Fukushima Dai-ichi Nuclear Power Plant in Japan. As a result, the U.S. Nuclear Regulatory Commission directed that a systematic and methodical review of Commission processes and regulations be performed to determine whether the agency should make additional improvements to its regulatory system and to make recommendations to the Commission. Two of the recommendations of the Task Force created to inform the Commission were: establish a logical, systematic, and coherent regulatory framework for adequate protection that appropriately balances defense-in-depth and risk considerations and that the NRC require licensees to reevaluate and upgrade as necessary the design-basis flooding protection of structures, systems, and components for each operating reactor. These recommendations came at the same time as technical discussions about updating approaches to evaluate flood hazard were underway. These discussions included: consideration of climate nonstationarity in flood assessments; transitioning from PMP/PMF assessments to probabilistic flood analyses to better align with risk-informed decision making; and systematic consideration of combined events in flood risk analysis. There is no scientific basis to assume that shifts in long-term mean precipitation and temperature (such as is commonly derived from climate models) relate to flood probability. Flood mechanisms are often more complex and reflect climate pattern anomalies more than mean annual shifts. Instead of discounting historical data due to climatic nonstationarity, it is important to better understand the climate patterns that have triggered floods in the past and to look to climate forecasts to understand the likely changes in the frequency of those historical climate patterns with climate change. It is equally important to have a better understanding of whether climate change will result in flood-generating climate systems heretofore unknown in the particular locale. This presentation will provide a roadmap to ensuring that the flood hazards of existing and future nuclear power plants are well defined.

On the value of satellite-based river discharge and river flood data

NASA Astrophysics Data System (ADS)

Kettner, A. J.; Brakenridge, R.; van Praag, E.; Borrero, S.; Slayback, D. A.; Young, C.; Cohen, S.; Prades, L.; de Groeve, T.

2015-12-01

Flooding is the most common natural hazard worldwide. According to the World Resources Institute, floods impact 21 million people every year and affect the global GDP by $96 billion. Providing accurate flood maps in near-real time (NRT) is critical to their utility to first responders. Also, in times of flooding, river gauging stations on location, if any, are of less use to monitor stage height as an approximation for water surface area, as often the stations themselves get washed out or peak water levels reach much beyond their design measuring capacity. In a joint effort with NASA Goddard Space Flight Center, the European Commission Joint Research Centre and the University of Alabama, the Dartmouth Flood Observatory (DFO) measures NRT: 1) river discharges, and 2) water inundation extents, both with a global coverage on a daily basis. Satellite-based passive microwave sensors and hydrological modeling are utilized to establish 'remote-sensing based discharge stations'. Once calibrated, daily discharge time series span from 1998 to the present. Also, the two MODIS instruments aboard the NASA Terra and Aqua satellites provide daily floodplain inundation extent with global coverage at a spatial resolution of 250m. DFO's mission is to provide easy access to NRT river and flood data products. Apart from the DFO web portal, several water extent products can be ingested by utilizing a Web Map Service (WMS), such as is established with for Latin America and the Caribbean (LAC) region through the GeoSUR program portal. This effort includes implementing over 100 satellite discharge stations showing in NRT if a river is flooding, normal, or in low flow. New collaborative efforts have resulted in flood hazard maps which display flood extent as well as exceedance probabilities. The record length of our sensors allows mapping the 1.5 year, 5 year and 25 year flood extent. These can provide key information to water management and disaster response entities.

The Generation of a Stochastic Flood Event Catalogue for Continental USA

NASA Astrophysics Data System (ADS)

Quinn, N.; Wing, O.; Smith, A.; Sampson, C. C.; Neal, J. C.; Bates, P. D.

2017-12-01

Recent advances in the acquisition of spatiotemporal environmental data and improvements in computational capabilities has enabled the generation of large scale, even global, flood hazard layers which serve as a critical decision-making tool for a range of end users. However, these datasets are designed to indicate only the probability and depth of inundation at a given location and are unable to describe the likelihood of concurrent flooding across multiple sites.Recent research has highlighted that although the estimation of large, widespread flood events is of great value to flood mitigation and insurance industries, to date it has been difficult to deal with this spatial dependence structure in flood risk over relatively large scales. Many existing approaches have been restricted to empirical estimates of risk based on historic events, limiting their capability of assessing risk over the full range of plausible scenarios. Therefore, this research utilises a recently developed model-based approach to describe the multisite joint distribution of extreme river flows across continental USA river gauges. Given an extreme event at a site, the model characterises the likelihood neighbouring sites are also impacted. This information is used to simulate an ensemble of plausible synthetic extreme event footprints from which flood depths are extracted from an existing global flood hazard catalogue. Expected economic losses are then estimated by overlaying flood depths with national datasets defining asset locations, characteristics and depth damage functions. The ability of this approach to quantify probabilistic economic risk and rare threshold exceeding events is expected to be of value to those interested in the flood mitigation and insurance sectors.This work describes the methodological steps taken to create the flood loss catalogue over a national scale; highlights the uncertainty in the expected annual economic vulnerability within the USA from extreme river flows; and presents future developments to the modelling approach.

Flood hydrology and dam-breach hydraulic analyses of four reservoirs in the Black Hills, South Dakota

USGS Publications Warehouse

Hoogestraat, Galen K.

2011-01-01

Extensive information about the construction of dams or potential downstream hazards in the event of a dam breach is not available for many small reservoirs within the Black Hills National Forest. In 2009, the U.S. Forest Service identified the need for reconnaissance-level dam-breach assessments for four of these reservoirs within the Black Hills National Forest (Iron Creek, Horsethief, Lakota, and Mitchell Lakes) with the potential to flood downstream structures. Flood hydrology and dam-breach hydraulic analyses for the four selected reservoirs were conducted by the U.S. Geological Survey in cooperation with the U.S. Forest service to estimate the areal extent of downstream inundation. Three high-flow breach scenarios were considered for cases when the dam is in place (overtopped) and when a dam break (failure) occurs: the 100-year recurrence 24-hour precipitation, 500-year recurrence peak flow, and the probable maximum precipitation. Inundation maps were developed that show the estimated extent of downstream floodwaters from simulated scenarios. Simulation results were used to determine the hazard classification of a dam break (high, significant, or low), based primarily on the potential for loss of life or property damage resulting from downstream inundation because of the flood surge.The inflow design floods resulting from the two simulated storm events (100-year 24-hour and probable maximum precipitation) were determined using the U.S. Army Corps of Engineers Hydrologic Engineering Center Hydrologic Modeling System (HEC-HMS). The inflow design flood for the 500-year recurrence peak flow was determined by using regional regression equations developed for streamflow-gaging stations with similar watershed characteristics. The step-backwater hydraulic analysis model, Hydrologic Engineering Center's River Analysis System (HEC-RAS), was used to determine water-surface profiles of in-place and dam-break scenarios for the three inflow design floods that were simulated. Inundation maps for in-place and dam-break scenarios were developed for the area downstream from the dam to the mouth of each stream.Dam-break scenarios for three of the four reservoirs assessed in this study were rated as low hazards owing to absence of permanent structures downstream from the dams. Iron Creek Lake's downstream channel to its mouth does not include any permanent structures within the inundation flood plains. For the two reservoirs with the largest watershed areas, Lakota and Mitchell Lake, the additional floodwater surge resulting from a dam break would be minor relative to the magnitude of the large flood streamflow into the reservoirs, based on the similar areal extent of inundation for the in-place and dam-break scenarios as indicated by the developed maps. A dam-break scenario at Horsethief Lake is rated as a significant hazard because of potential lives-in-jeopardy in downstream dwellings and appreciable economic loss.

Allowances for evolving coastal flood risk under uncertain local sea-level rise

NASA Astrophysics Data System (ADS)

Buchanan, M. K.; Kopp, R. E.; Oppenheimer, M.; Tebaldi, C.

2015-12-01

Sea-level rise (SLR) causes estimates of flood risk made under the assumption of stationary mean sea level to be biased low. However, adjustments to flood return levels made assuming fixed increases of sea level are also inaccurate when applied to sea level that is rising over time at an uncertain rate. To accommodate both the temporal dynamics of SLR and their uncertainty, we develop an Average Annual Design Life Level (AADLL) metric and associated SLR allowances [1,2]. The AADLL is the flood level corresponding to a time-integrated annual expected probability of occurrence (AEP) under uncertainty over the lifetime of an asset; AADLL allowances are the adjustment from 2000 levels that maintain current risk. Given non-stationary and uncertain SLR, AADLL flood levels and allowances provide estimates of flood protection heights and offsets for different planning horizons and different levels of confidence in SLR projections in coastal areas. Allowances are a function primarily of local SLR and are nearly independent of AEP. Here we employ probabilistic SLR projections [3] to illustrate the calculation of AADLL flood levels and allowances with a representative set of long-duration tide gauges along U.S. coastlines. [1] Rootzen et al., 2014, Water Resources Research 49: 5964-5972. [2] Hunter, 2013, Ocean Engineering 71: 17-27. [3] Kopp et al., 2014, Earth's Future 2: 383-406.

Nationwide summary of US Geological Survey regional regression equations for estimating magnitude and frequency of floods for ungaged sites, 1993

USGS Publications Warehouse

Jennings, M.E.; Thomas, W.O.; Riggs, H.C.

1994-01-01

For many years, the U.S. Geological Survey (USGS) has been involved in the development of regional regression equations for estimating flood magnitude and frequency at ungaged sites. These regression equations are used to transfer flood characteristics from gaged to ungaged sites through the use of watershed and climatic characteristics as explanatory or predictor variables. Generally these equations have been developed on a statewide or metropolitan area basis as part of cooperative study programs with specific State Departments of Transportation or specific cities. The USGS, in cooperation with the Federal Highway Administration and the Federal Emergency Management Agency, has compiled all the current (as of September 1993) statewide and metropolitan area regression equations into a micro-computer program titled the National Flood Frequency Program.This program includes regression equations for estimating flood-peak discharges and techniques for estimating a typical flood hydrograph for a given recurrence interval peak discharge for unregulated rural and urban watersheds. These techniques should be useful to engineers and hydrologists for planning and design applications. This report summarizes the statewide regression equations for rural watersheds in each State, summarizes the applicable metropolitan area or statewide regression equations for urban watersheds, describes the National Flood Frequency Program for making these computations, and provides much of the reference information on the extrapolation variables needed to run the program.

PHYSICAL MODELING OF CONTRACTED FLOW.

USGS Publications Warehouse

Lee, Jonathan K.

1987-01-01

Experiments on steady flow over uniform grass roughness through centered single-opening contractions were conducted in the Flood Plain Simulation Facility at the U. S. Geological Survey's Gulf Coast Hydroscience Center near Bay St. Louis, Miss. The experimental series was designed to provide data for calibrating and verifying two-dimensional, vertically averaged surface-water flow models used to simulate flow through openings in highway embankments across inundated flood plains. Water-surface elevations, point velocities, and vertical velocity profiles were obtained at selected locations for design discharges ranging from 50 to 210 cfs. Examples of observed water-surface elevations and velocity magnitudes at basin cross-sections are presented.

Evaluation of the best fit distribution for partial duration series of daily rainfall in Madinah, western Saudi Arabia

NASA Astrophysics Data System (ADS)

Alahmadi, F.; Rahman, N. A.; Abdulrazzak, M.

2014-09-01

Rainfall frequency analysis is an essential tool for the design of water related infrastructure. It can be used to predict future flood magnitudes for a given magnitude and frequency of extreme rainfall events. This study analyses the application of rainfall partial duration series (PDS) in the vast growing urban Madinah city located in the western part of Saudi Arabia. Different statistical distributions were applied (i.e. Normal, Log Normal, Extreme Value type I, Generalized Extreme Value, Pearson Type III, Log Pearson Type III) and their distribution parameters were estimated using L-moments methods. Also, different selection criteria models are applied, e.g. Akaike Information Criterion (AIC), Corrected Akaike Information Criterion (AICc), Bayesian Information Criterion (BIC) and Anderson-Darling Criterion (ADC). The analysis indicated the advantage of Generalized Extreme Value as the best fit statistical distribution for Madinah partial duration daily rainfall series. The outcome of such an evaluation can contribute toward better design criteria for flood management, especially flood protection measures.

SURFACTANT - POLYMER INTERACTION FOR IMPROVED OIL RECOVERY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Unknown

1998-10-01

The goal of this research is to use the interaction between a surfactant and a polymer for efficient displacement of tertiary oil by improving slug integrity, adsorption and mobility control. Surfactant--polymer flooding has been shown to be highly effective in laboratory-scale linear floods. The focus of this proposal is to design an inexpensive surfactant-polymer mixture that can efficiently recover tertiary oil by avoiding surfactant slug degradation high adsorption and viscous/heterogeneity fingering. A mixture comprising a ''pseudo oil'' with appropriate surfactant and polymer has been selected to study micellar-polymer chemical flooding. The physical properties and phase behavior of this system havemore » been determined. A surfactant-polymer slug has been designed to achieve high efficiency recovery by improving phase behavior and mobility control. Recovery experiments have been performed on linear cores and a quarter 5-spot. The same recovery experiments have been simulated using a commercially available simulator (UTCHEM). Good agreement between experimental data and simulation results has been achieved.« less

The application of remote sensing to the development and formulation of hydrologic planning models

NASA Technical Reports Server (NTRS)

Castruccio, P. A.; Loats, H. L., Jr.; Fowler, T. R.; Frech, S. L.

1975-01-01

Regional hydrologic planning models built upon remote sensing capabilities and suited for ungaged watersheds are developed. The effectiveness of such models is determined along with which parameters impact most the minimization of errors associated with the prediction of peak flow events (floods). Emphasis is placed on peak flood prediction because of its significance to users for the purpose of planning, sizing, and designing waterworks.

Pathways to designing and running an operational flood forecasting system: an adventure game!

NASA Astrophysics Data System (ADS)

Arnal, Louise; Pappenberger, Florian; Ramos, Maria-Helena; Cloke, Hannah; Crochemore, Louise; Giuliani, Matteo; Aalbers, Emma

2017-04-01

In the design and building of an operational flood forecasting system, a large number of decisions have to be taken. These include technical decisions related to the choice of the meteorological forecasts to be used as input to the hydrological model, the choice of the hydrological model itself (its structure and parameters), the selection of a data assimilation procedure to run in real-time, the use (or not) of a post-processor, and the computing environment to run the models and display the outputs. Additionally, a number of trans-disciplinary decisions are also involved in the process, such as the way the needs of the users will be considered in the modelling setup and how the forecasts (and their quality) will be efficiently communicated to ensure usefulness and build confidence in the forecasting system. We propose to reflect on the numerous, alternative pathways to designing and running an operational flood forecasting system through an adventure game. In this game, the player is the protagonist of an interactive story driven by challenges, exploration and problem-solving. For this presentation, you will have a chance to play this game, acting as the leader of a forecasting team at an operational centre. Your role is to manage the actions of your team and make sequential decisions that impact the design and running of the system in preparation to and during a flood event, and that deal with the consequences of the forecasts issued. Your actions are evaluated by how much they cost you in time, money and credibility. Your aim is to take decisions that will ultimately lead to a good balance between time and money spent, while keeping your credibility high over the whole process. This game was designed to highlight the complexities behind decision-making in an operational forecasting and emergency response context, in terms of the variety of pathways that can be selected as well as the timescale, cost and timing of effective actions.

Increasing resilience through participative flood risk map design

NASA Astrophysics Data System (ADS)

Fuchs, Sven; Spira, Yvonne; Stickler, Therese

2013-04-01

In recent years, an increasing number of flood hazards has shown to the European Commission and the Member States of the European Union the importance of flood risk management strategies in order to reduce losses and to protect the environment and the citizens. Exposure to floods as well as flood vulnerability might increase across Europe due to the ongoing economic development in many EU countries. Thus even without taking climate change into account an increase of flood disasters in Europe might be foreseeable. These circumstances have produced a reaction in the European Commission, and a Directive on the Assessment and Management of Flood Risks was issued as one of the three components of the European Action Programme on Flood Risk Management. Floods have the potential to jeopardise economic development, above all due to an increase of human activities in floodplains and the reduction of natural water retention by land use activities. As a result, an increase in the likelihood and adverse impacts of flood events is expected. Therefore, concentrated action is needed at the European level to avoid severe impacts on human life and property. In order to have an effective tool available for gathering information, as well as a valuable basis for priority setting and further technical, financial and political decisions regarding flood risk mitigation and management, it is necessary to provide for the establishment of flood risk maps which show the potential adverse consequences associated with different flood scenarios. So far, hazard and risk maps are compiled in terms of a top-down linear approach: planning authorities take the responsibility to create and implement these maps on different national and local scales, and the general public will only be informed about the outcomes (EU Floods Directive, Article 10). For the flood risk management plans, however, an "active involvement of interested parties" is required, which means at least some kind of multilateral consultation on the management plans that allows stakeholders to discuss relevant issues and to contribute to arguments and propositions put forward by the stakeholders. Through a wider stakeholder participation and more effective communication, awareness of flood risks should be raised. With the term participation diverse voluntary and informal forms of inclusion are summarized (in contrast to legal forms of participation like the status as a party). When discussing the theoretical and practical implications of participation in flood risk management, it is important to make a clear distinction between public and stakeholder participation. The broad public is "everybody" and refers to the participation by non-organised individuals as members of the general public, and specifically to individuals whose profession is not connected to flood risk management. As such, they have to be regarded as lay persons, which, nevertheless, does not mean that these individuals do not have any idea about the hazard they are exposed to or can contribute to the quality of an decision making process. In contrast to professionally interested parties, this group is typically comprised of individuals with different individual perspectives on flood risk management. It is argued that including practical knowledge and perceptions (reflecting values and preferences) into the flood risk management process is - apart from professional assessments (as systematic knowledge) - a milestone towards adequate governance structures in any institutional process with political legitimacy. Neither normative concepts like sustainable development or "Good Governance" nor the European Water Framework Directive 2000/60/EC do specify what public participation or the participation of user means in detail. As also scientific literature offers no consistent definition of public participation and stakeholder participation we developed an innovative approach used in the pilot project Krems, Austria. The most innovative step regarding participation was not the methods used for participation but the involvement of concerned lay persons not only in the design of the hazard and risk maps or the risk assessments itself but the cooperative elaboration of the risk assessment approach especially for the harbour area. Following these principles, flood risk maps were created in the underlying EU-project DANUBE FLOODRISK. In this ETC SEE project "DANUBE FLOODRISK - Stakeholder Oriented Assessment of the Danube Floodplains" (2009-2012), hazard and risk maps harmonized across borders for the Danube main stream were produced. This way the overall DANUBE FLOODRISK project contributed to Article 6 of the EU Floods Directive, the hazard and risk maps for international river basins, and provides with the involvement of the national and regional stakeholders the first step to the implementation of Article 7, the Flood Risk Management Plans. By testing the involvement of the broad public and local stakeholders, first exemplary steps were taken for local flood risk management planning. A first set of maps was created for an underlying hazard scenario of a 1-in-100 year flood affecting the city of Krems assuming a failure of the temporal flood protection due to the impact of a ship in the area of the pier. Moreover, both, hazard scenarios with and without a second line of defence were visualised. The set of maps includes (a) an evaluative risk map showing the risk qualitatively aggregated for each building exposed and the number of affected citizens, (b) an evaluative risk map showing the risk qualitatively aggregated per square footage for each building exposed and the number of affected citizens, (c) an evaluative risk map showing the risk quantitatively in monetary units per square footage for each building exposed and the number of affected citizens, and (d) as well as (e) risk maps according to (a) and (b) without the second line of defence in order to communicate the effectiveness of temporal flood protection. For the harbour of Krems, a risk map was compiled based on a self-evaluation of the effects of flooding by the harbour companies. This risk map was based on the assumption of a failure of the harbour gate during a flood event. The self-evaluation was undertaken based on a developed risk matrix which includes significant adverse impacts on human health, the environment, cultural heritage and economic activity. Insights on stakeholder-oriented risk communication were gained with respect to the design and the layout of the maps. Specific elements of semiology for the cartographic representation were deduced. The pilot initiative discussed in this paper is brought added value to all involved parties so far. All participants brought in knowledge, data and time resources. The project team was involved in a social learning process and gained additional know-how about adequate stakeholder involvement and communication as well as about risk assessment methods and mapping. It could be shown that it is possible to involve lay persons in topics such as risk assessments so far only defined by technical experts. Stakeholders from the harbour area were not only involved in the risk assessment but also in the development of the methods for this risk assessment. Such approaches may be increasingly used to develop a better understanding of flood risk within affected communities, and thus increase flood resilience.

Mitigation of negative ecological and socio-economic impacts of the Diama dam on the Senegal River Delta wetland (Mauritania), using a model based decision support system

NASA Astrophysics Data System (ADS)

Duvail, S.; Hamerlynck, O.

Protection from annual flooding is correlated with increased cholera prevalence in Bangladesh: a zero-inflated regression analysis.

PubMed

Carrel, Margaret; Voss, Paul; Streatfield, Peter K; Yunus, Mohammad; Emch, Michael

2010-03-22

Alteration of natural or historical aquatic flows can have unintended consequences for regions where waterborne diseases are endemic and where the epidemiologic implications of such change are poorly understood. The implementation of flood protection measures for a portion of an intensely monitored population in Matlab, Bangladesh, allows us to examine whether cholera outcomes respond positively or negatively to measures designed to control river flooding. Using a zero inflated negative binomial model, we examine how selected covariates can simultaneously account for household clusters reporting no cholera from those with positive counts as well as distinguishing residential areas with low counts from areas with high cholera counts. Our goal is to examine how residence within or outside a flood protected area interacts with the probability of cholera presence and the effect of flood protection on the magnitude of cholera prevalence. In Matlab, living in a household that is protected from annual monsoon flooding appears to have no significant effect on whether the household experiences cholera, net of other covariates. However, counter-intuitively, among households where cholera is reported, living within the flood protected region significantly increases the number of cholera cases. The construction of dams or other water impoundment strategies for economic or social motives can have profound and unanticipated consequences for waterborne disease. Our results indicate that the construction of a flood control structure in rural Bangladesh is correlated with an increase in cholera cases for residents protected from annual monsoon flooding. Such a finding requires attention from both the health community and from governments and non-governmental organizations involved in ongoing water management schemes.

Exploring local risk managers' use of flood hazard maps for risk communication purposes in Baden-Württemberg

NASA Astrophysics Data System (ADS)

Kjellgren, S.

2013-07-01

In response to the EU Floods Directive (2007/60/EC), flood hazard maps are currently produced all over Europe, reflecting a wider shift in focus from "flood protection" to "risk management", for which not only public authorities but also populations at risk are seen as responsible. By providing a visual image of the foreseen consequences of flooding, flood hazard maps can enhance people's knowledge about flood risk, making them more capable of an adequate response. Current literature, however, questions the maps' awareness raising capacity, arguing that their content and design are rarely adjusted to laypeople's needs. This paper wants to complement this perspective with a focus on risk communication by studying how these tools are disseminated and marketed to the public in the first place. Judging from communication theory, simply making hazard maps publicly available is unlikely to lead to attitudinal or behavioral effects, since this typically requires two-way communication and material or symbolic incentives. Consequently, it is relevant to investigate whether and how local risk managers, who are well positioned to interact with the local population, make use of flood hazard maps for risk communication purposes. A qualitative case study of this issue in the German state of Baden-Württemberg suggests that many municipalities lack a clear strategy for using this new information tool for hazard and risk communication. Four barriers in this regard are identified: perceived disinterest/sufficient awareness on behalf of the population at risk; unwillingness to cause worry or distress; lack of skills and resources; and insufficient support. These barriers are important to address - in research as well as in practice - since it is only if flood hazard maps are used to enhance local knowledge resources that they can be expected to contribute to social capacity building.

Coping capacities for improving adaptation pathways for flood protection in Can Tho, Vietnam

NASA Astrophysics Data System (ADS)

Pathirana, A.; Radhakrishnan, M.; Quan, N. H.; Gersonius, B.; Ashley, R.; Zevenbergen, C.

2016-12-01

Studying the evolution of coping and adaptation capacities is a prerequisite for preparing an effective flood management plan for the future, especially in the dynamic and fast changing cities of developing countries. The objectives, requirements, targets, design and performance of flood protection measures will have to be determined after taking into account, or in conjunction with, the coping capacities. A methodology is presented based on adaptation pathways to account for coping capacities and to assess the effect on flood protection measures. The adaptation pathways method determines the point of failure of a particular strategy based on the change in an external driver, a point in time or a socio economic situation where / at which the strategy can no longer meet its objective. Pathways arrived at based on this methodology reflect future reality by considering changing engineering standards along with future uncertainties, risk taking abilities and adaptation capacities. This pathways based methodology determines the Adaptation tipping points (ATP), `time of occurrence of ATP' of flood protection measures after accounting for coping capacities, evaluates the measures and then provides the means to determine the adaptation pathways. Application of this methodology for flood protection measures in Can Tho city in the Mekong delta reveals the effect of coping capacity on the usefulness of flood protection measures and the delay in occurrence of tipping points. Consideration of coping capacity in the system owing to elevated property floor levels lead to the postponement of tipping points and improved the adaptation pathways comprising flood protection measures such as dikes. This information is useful to decision makers for planning and phasing of investments in flood protection.

Using Levee Setbacks to Increase Floodplain Connectivity and Reduce Flood Risk

NASA Astrophysics Data System (ADS)

Dahl, T. A.; Echevarria-Doyle, W.

2017-12-01

Levees typically constrain flood flows to within the main channel, isolating the river from its natural floodplain. Levees limit the areal and temporal extents of flooding, but can increase flood peaks, alter ecosystems, and cause scour. In order to mitigate these effects, some groups have begun moving portions of levees further away from the main channel, creating setback levees. Here we describe a series of levee setback scenarios for a hypothetical river that were modeled with the unsteady, 2D-hydraulic model AdH. In our scenarios, the water surface elevations were reduced both at the location of the levee setback and for some distance upstream. The models also show that the floodplain roughness can have a greater effect on the reduction in water surface elevation than the size of the levee setback. Groups planning levee setbacks can use these results to help guide their designs.

Numerical simulation of field scale cosolvent flooding for LNAPL remediation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roeder, E.; Brame, S.E.; Falta, R.W.

1995-12-31

This paper describes a modeling study which will support remediation of contaminated soils at Hill Air Force Base in Utah. The site is contaminated with a mixture of solvents, jet fuel, and other organic substances which form a separate phase of low density on top of the water table. A test cell within the contaminant zone will be flooded with a cosolvent/water mixture to drive the nonaqueous phase liquids (NAPLs) out. The modeling study is designed to deterine if buoyancy of the flooding solution will cause it to float on top, if heterogeneity of the ground will channel the cosolventmore » around pockets of NAPL, and the sensitivity of the predicted remediation effectiveness to the uncertainty in ternary information. The modeling effort will use UTCHEM, a 3-dimensional finite-difference flooding simulator which solves mass balance equations for up to 21 components in up to 4 phases.« less

The influence of gender and age on choice of flood adaptation strategies: A case study of Zambia and Namibia..

NASA Astrophysics Data System (ADS)

Mabuku, Monde

2017-04-01

It is reported that flood events will increase due to variability and change in climate, thus increasing the number of people exposed to flooding disasters. This exposure negatively impacts rural households' livelihoods. Women, men, young, old has distinctive vulnerability and this shapes the choice of flood adaptation strategies. This calls for a need to adopt group specific interventions to strengthen local adaptive capacity to flooding for the affected population. The purpose of this case study was to determine the adaptation strategies to floods adopted by rural households in the Zambezi region of Namibia and Mwandi district of Zambia. The study further examined how gender and age influenced the choice of different adaptation strategies. Six focus group meetings and a questionnaire survey of 207 randomly sampled households were conducted in the flood prone areas of the study. Descriptive statistics results on the adaptation strategies indicated that a majority of the households in Namibia learnt to live with floods (86%),practiced mafisa cattle trade (86%), flood water harvesting (68%), practiced early and late planting (63%), prayed (55%), practiced conservation agriculture (54%) and fish farming (53%). In Zambia the adaptation strategies were; conservation agriculture (91%), acquiring better skills on preparedness (66%), flood water harvesting (63%), praying (60%), and flood proofing (52%). Logistic regression analysis showed that age positively and significantly influenced the likelihood of taking up adaptation strategies such as tree planting, relocation to higher ground, flood water harvesting, early and late planting. The older the respondents the more likely they were to adopt the strategies mentioned. More young ones were more likely to adopt acquiring better skills on flood preparedness and mafisa cattle trading than the old ones. Gender positively and significantly influenced mafisa cattle trade (p<0.01), male headed households were more likely to adopt mafisa cattle trading than the females. The study concludes that factors such as age and gender influences the choice of any adaptation strategy. For policy purposes, this suggests that relevant stakeholders' interventions should consider gender and age in order to enhance the adaptive capacity of rural households to flooding. This study will inform decision makers and practitioners to consider women and men, young and old in designing programs and projects aimed at strengthening disaster risk reduction and management in the two countries and under similar environments.

Exploring the feasibility of private micro flood insurance provision in Bangladesh.

PubMed

Akter, Sonia; Brouwer, Roy; van Beukering, Pieter J H; French, Laura; Silver, Efrath; Choudhury, Saria; Aziz, Syeda Salina

2011-04-01

This paper aims to contribute to the debate on the feasibility of the provision of micro flood insurance as an effective tool for spreading disaster risks in developing countries and examines the role of the institutional-organisational framework in assisting the design and implementation of such a micro flood insurance market. In Bangladesh, a private insurance market for property damage and livelihood risk due to natural disasters does not exist. Private insurance companies are reluctant to embark on an evidently unprofitable venture. Testing two different institutional-organisational models, this research reveals that the administration costs of micro-insurance play an important part in determining the long-term viability of micro flood insurance schemes. A government-facilitated process to overcome the differences observed in this study between the nonprofit micro-credit providers and profit-oriented private insurance companies is needed, building on the particular competence each party brings to the development of a viable micro flood insurance market through a public-private partnership. © 2011 The Author(s). Disasters © Overseas Development Institute, 2011.

Assessing and optimising flood control options along the Arachthos river floodplain (Epirus, Greece)

NASA Astrophysics Data System (ADS)

Drosou, Athina; Dimitriadis, Panayiotis; Lykou, Archontia; Kossieris, Panagiotis; Tsoukalas, Ioannis; Efstratiadis, Andreas; Mamassis, Nikos

2015-04-01

We present a multi-criteria simulation-optimization framework for the optimal design and setting of flood protection structures along river banks. The methodology is tested in the lower course of the Arachthos River (Epirus, Greece), downstream of the hydroelectric dam of Pournari. The entire study area is very sensitive, particularly because the river crosses the urban area of Arta, which is located just after the dam. Moreover, extended agricultural areas that are crucial for the local economy are prone to floods. In the proposed methodology we investigate two conflicting criteria, i.e. the minimization of flood hazards (due to damages to urban infrastructures, crops, etc.) and the minimization of construction costs of the essential hydraulic structures (e.g. dikes). For the hydraulic simulation we examine two flood routing models, named 1D HEC-RAS and quasi-2D LISFLOOD, whereas the optimization is carried out through the Surrogate-Enhanced Evolutionary Annealing-Simplex (SE-EAS) algorithm that couples the strengths of surrogate modeling with the effectiveness and efficiency of the EAS method.

Appropriate rehabilitation strategy for a traditional irrigation supply system: a case from the Babai area in Nepal.

PubMed

Adhikari, B; Verhoeven, R; Troch, P

2009-01-01

This paper studies primary canals of three traditional irrigation systems in the southern plains of Nepal. It offers a scientific interpretation of the indigenous technology applied to the systems, which facilitates to use the same channel network for irrigation, drainage and flood management. The flood management technology of the farmers by diverting as much discharge as possible to the field channels results in the reduction of discharge towards the downstream part of the main channel. It is depicted in the simulation study that uses the river analysis program HEC-RAS 4.0. A cascade of weirs is found to be the most cost effective and user-friendly option to upgrade these systems preserving the existing irrigation, drainage as well as flood management functions. This study suggests that the conventional irrigation design principles should be applied very cautiously with full knowledge of the existing socio-institutional setting, hydro-ecological regime and indigenous technology for upgrading any traditional irrigation system successfully. The indigenous flood management technology strengthens the emerging concept that the floods in the Ganges plain are to be managed, not controlled.

After the flood is before the next flood - post event review of the Central European Floods of June 2013. Insights, recommendations and next steps for future flood prevention

NASA Astrophysics Data System (ADS)

Szoenyi, Michael; Mechler, Reinhard; McCallum, Ian

2015-04-01

In early June 2013, severe flooding hit Central and Eastern Europe, causing extensive damage, in particular along the Danube and Elbe main watersheds. The situation was particularly severe in Eastern Germany, Austria, Hungary and the Czech Republic. Based on the Post Event Review Capability (PERC) approach, developed by Zurich Insurance's Flood Resilience Program to provide independent review of large flood events, we examine what has worked well (best practice) and opportunities for further improvement. The PERC overall aims to thoroughly examine aspects of flood resilience, flood risk management and catastrophe intervention in order to help build back better after events and learn for future events. As our research from post event analyses shows a lot of losses are in fact avoidable by taking the right measures pre-event and these measures are economically - efficient with a return of 4 Euro on losses saved for every Euro invested in prevention on average (Wharton/IIASA flood resilience alliance paper on cost benefit analysis, Mechler et al. 2014) and up to 10 Euros for certain countries. For the 2013 flood events we provide analysis on the following aspects and in general identify a number of factors that worked in terms of reducing the loss and risk burden. 1. Understanding risk factors of the Central European Floods 2013 We review the precursors leading up to the floods in June, with an extremely wet May 2013 and an atypical V-b weather pattern that brought immense precipitation in a very short period to the watersheds of Elbe, Donau and partially the Rhine in the D-A-CH countries and researched what happened during the flood and why. Key questions we asked revolve around which protection and risk reduction approaches worked well and which did not, and why. 2. Insights and recommendations from the post event review The PERC identified a number of risk factors, which need attention if risk is to be reduced over time. • Yet another "100-year flood" - risk perception and understanding of risk in the population. • Residual risk and the levee shadow effect - why the population "felt safe." • What is the overload case and how to implement it in flood protection systems? • Decision-making for the future under uncertainty - how to design to acceptable flood protection levels if we haven't seen yet what's physically possible. 3. How to protect - practical examples Finally, we outline practical examples for reducing the loss burden and risk over time. • "Flood protection hierarchy" - from location choice under a hazard perspective to mobile flood protection. • Risk-based approach and identification of critical infrastructure. • Integrated flood risk management in theory and practical application. • Role of insurance.

Gender, age and circumstances analysis of flood and landslide fatalities in Italy.

PubMed

Salvati, Paola; Petrucci, Olga; Rossi, Mauro; Bianchi, Cinzia; Pasqua, Aurora A; Guzzetti, Fausto

2018-01-01

Floods and landslides are frequent and destructive geo-hydrological hazards that cause harm to people every year. We analysed data on 1292 landslide and 771 flood fatalities that occurred in Italy in the 50-year period 1965-2014, to determine the dependence of the fatalities on gender and age and the circumstances of death by type of hazard. The multinomial probability mass function of the expected fatalities by gender and age, as reported by national census data, were estimated and compared with the observed landslide and flood fatalities. We identified the age categories over or under represented when the observed fatalities were respectively higher or lower than the modelled expected deaths. We found that in Italy males are more vulnerable to floods and landslides for most of the age categories. Apart from children, males are over-represented up to the age of 89 for floods and up to 79 for landslides, whereas females are under-represented up to the age of 59 for floods and landslides, and over-represented above 70 for floods and between 60 and 79 for landslides. To consider the demographic and socio-cultural changes over time, we performed a temporal analysis splitting the record into two non-overlapping subsets of 25year each. The analysis demonstrated that the over-representation of males compared to the females, both for landslide and flood is statistically significant and does not vary in time, indicating a different propensity towards the risk taking and a different degree of exposure between males and females. Analysis of the data allowed to identify the common circumstances of death. Landslides fatalities occurred frequently indoor, whereas the majority of the flood fatalities occurred outdoor, outlining the different dynamics of the hazards. Floods killed numerous people along roads and drivers or passengers travelling in vehicles. We expect that the results of this work will be helpful to design recommendations for self-protecting actions, and proactive policies that can contribute to reduce the human toll of floods and landslides in Italy, and elsewhere. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Frequency assessment of spatially distributed generations of flood scenarios: an application on Italian territory

NASA Astrophysics Data System (ADS)

Lomazzi, M.; Roth, G.; Rudari, R.; Taramasso, A. C.; Ghizzoni, T.; Benedetti, R.; Espa, G.; Terpessi, C.

2009-12-01

The flooding risk impact on society cannot be understated: it influences land use and territorial planning and development at both physical and regulatory levels. To cope with it, a variety of actions can be put in place, involving multidisciplinary competences. Mitigation measures goes from the improvement of monitoring systems to the development of hydraulic structures, throughout land use restrictions, civil protection and insurance plans. All of those options present social and economic impacts, either positive or negative, whose proper estimate should rely on the assumption of appropriate - present and future - scenarios, i.e. quantitative event descriptions in terms of i) the flood hazard, with its probability of occurrence, extension, intensity, and duration, ii) the exposed values and iii) their vulnerability. At present, initial attention has been devoted to the design of flood scenarios, or ensembles of them, and to the evaluation of their frequency of occurrence. In the present work, a model for spatially distributed flood scenarios generation and frequency assessment is proposed and applied to the Italian territory. The study area has been divided into homogeneous regions according to their hydrologic, orographic and meteoclimatic characteristics. A statistical model for flood scenarios simulation has been implemented throughout a conditional approach based on MCMC simulations by using i) a historical flood events catalogue; ii) a homogeneous regions correlation matrix; and iii) an auxiliary variables data set. In this framework, the role of the information stored in the historical flood events catalogue "Aree Vulnerate Italiane" (AVI, http://avi.gndci.cnr.it/), produced by the Italian National Research Council, is of crucial importance.

High Risk Flash Flood Rainstorm Mapping Based on Regional L-moments Approach

NASA Astrophysics Data System (ADS)

Ding, Hui; Liao, Yifan; Lin, Bingzhang

2017-04-01

Difficulties and complexities in elaborating flash flood early-warning and forecasting system prompt hydrologists to develop some techniques to substantially reduce the disastrous outcome of a flash flood in advance. An ideal to specify those areas that are subject at high risk to flash flood in terms of rainfall intensity in a relatively large region is proposed in this paper. It is accomplished through design of the High Risk Flash Flood Rainstorm Area (HRFFRA) based on statistical analysis of historical rainfall data, synoptic analysis of prevailing storm rainfalls as well as the field survey of historical flash flood events in the region. A HRFFRA is defined as the area potentially under hitting by higher intense-precipitation for a given duration with certain return period that may cause a flash flood disaster in the area. This paper has presented in detail the development of the HRFFRA through the application of the end-to-end Regional L-moments Approach (RLMA) to precipitation frequency analysis in combination with the technique of spatial interpolation in Jiangxi Province, South China Mainland. Among others, the concept of hydrometeorologically homogenous region, the precision of frequency analysis in terms of parameter estimation, the accuracy of quantiles in terms of uncertainties and the consistency adjustments of quantiles over durations and space, etc., have been addressed. At the end of this paper, the mapping of the HRFFRA and an internet-based visualized user-friendly data-server of the HRFFRA are also introduced. Key words: HRFFRA; Flash Flood; RLMA; rainfall intensity; Hydrometeorological homogenous region.

Influence of climate change on flood magnitude and seasonality in the Arga River catchment in Spain

NASA Astrophysics Data System (ADS)

Garijo, Carlos; Mediero, Luis

2018-04-01

Climate change projections suggest that extremes, such as floods, will modify their behaviour in the future. Detailed catchment-scale studies are needed to implement the European Union Floods Directive and give recommendations for flood management and design of hydraulic infrastructure. In this study, a methodology to quantify changes in future flood magnitude and seasonality due to climate change at a catchment scale is proposed. Projections of 24 global climate models are used, with 10 being downscaled by the Spanish Meteorological Agency (Agencia Estatal de Meteorología, AEMET) and 14 from the EURO-CORDEX project, under two representative concentration pathways (RCPs) 4.5 and 8.5, from the Fifth Assessment Report provided by the Intergovernmental Panel on Climate Change. Downscaled climate models provided by the AEMET were corrected in terms of bias. The HBV rainfall-runoff model was selected to simulate the catchment hydrological behaviour. Simulations were analysed through both annual maximum and peaks-over-threshold (POT) series. The results show a decrease in the magnitude of extreme floods for the climate model projections downscaled by the AEMET. However, results for the climate model projections downscaled by EURO-CORDEX show differing trends, depending on the RCP. A small decrease in the flood magnitude was noticed for the RCP 4.5, while an increase was found for the RCP 8.5. Regarding the monthly seasonality analysis performed by using the POT series, a delay in the flood timing from late-autumn to late-winter is identified supporting the findings of recent studies performed with observed data in recent decades.

Flood Risk Management: Exploring the Impacts of the Community Rating System Program on Poverty and Income Inequality.

PubMed

Noonan, Douglas S; Sadiq, Abdul-Akeem A

2018-03-01

Flooding remains a major problem for the United States, causing numerous deaths and damaging countless properties. To reduce the impact of flooding on communities, the U.S. government established the Community Rating System (CRS) in 1990 to reduce flood damages by incentivizing communities to engage in flood risk management initiatives that surpass those required by the National Flood Insurance Program. In return, communities enjoy discounted flood insurance premiums. Despite the fact that the CRS raises concerns about the potential for unevenly distributed impacts across different income groups, no study has examined the equity implications of the CRS. This study thus investigates the possibility of unintended consequences of the CRS by answering the question: What is the effect of the CRS on poverty and income inequality? Understanding the impacts of the CRS on poverty and income inequality is useful in fully assessing the unintended consequences of the CRS. The study estimates four fixed-effects regression models using a panel data set of neighborhood-level observations from 1970 to 2010. The results indicate that median incomes are lower in CRS communities, but rise in floodplains. Also, the CRS attracts poor residents, but relocates them away from floodplains. Additionally, the CRS attracts top earners, including in floodplains. Finally, the CRS encourages income inequality, but discourages income inequality in floodplains. A better understanding of these unintended consequences of the CRS on poverty and income inequality can help to improve the design and performance of the CRS and, ultimately, increase community resilience to flood disasters. © 2017 Society for Risk Analysis.

Using Hybrid Techniques for Generating Watershed-scale Flood Models in an Integrated Modeling Framework

NASA Astrophysics Data System (ADS)

Saksena, S.; Merwade, V.; Singhofen, P.

2017-12-01

There is an increasing global trend towards developing large scale flood models that account for spatial heterogeneity at watershed scales to drive the future flood risk planning. Integrated surface water-groundwater modeling procedures can elucidate all the hydrologic processes taking part during a flood event to provide accurate flood outputs. Even though the advantages of using integrated modeling are widely acknowledged, the complexity of integrated process representation, computation time and number of input parameters required have deterred its application to flood inundation mapping, especially for large watersheds. This study presents a faster approach for creating watershed scale flood models using a hybrid design that breaks down the watershed into multiple regions of variable spatial resolution by prioritizing higher order streams. The methodology involves creating a hybrid model for the Upper Wabash River Basin in Indiana using Interconnected Channel and Pond Routing (ICPR) and comparing the performance with a fully-integrated 2D hydrodynamic model. The hybrid approach involves simplification procedures such as 1D channel-2D floodplain coupling; hydrologic basin (HUC-12) integration with 2D groundwater for rainfall-runoff routing; and varying spatial resolution of 2D overland flow based on stream order. The results for a 50-year return period storm event show that hybrid model (NSE=0.87) performance is similar to the 2D integrated model (NSE=0.88) but the computational time is reduced to half. The results suggest that significant computational efficiency can be obtained while maintaining model accuracy for large-scale flood models by using hybrid approaches for model creation.

Exposure to Flood Hazards in Miami and Houston: Are Hispanic Immigrants at Greater Risk than Other Social Groups?

PubMed Central

Maldonado, Alejandra; Collins, Timothy W.; Grineski, Sara E.; Chakraborty, Jayajit

2016-01-01

Although numerous studies have been conducted on the vulnerability of marginalized groups in the environmental justice (EJ) and hazards fields, analysts have tended to lump people together in broad racial/ethnic categories without regard for substantial within-group heterogeneity. This paper addresses that limitation by examining whether Hispanic immigrants are disproportionately exposed to risks from flood hazards relative to other racial/ethnic groups (including US-born Hispanics), adjusting for relevant covariates. Survey data were collected for 1283 adult householders in the Houston and Miami Metropolitan Statistical Areas (MSAs) and flood risk was estimated using their residential presence/absence within federally-designated 100-year flood zones. Generalized estimating equations (GEE) with binary logistic specifications that adjust for county-level clustering were used to analyze (separately) and compare the Houston (N = 546) and Miami (N = 560) MSAs in order to clarify determinants of household exposure to flood risk. GEE results in Houston indicate that Hispanic immigrants have the greatest likelihood, and non-Hispanic Whites the least likelihood, of residing in a 100-year flood zone. Miami GEE results contrastingly reveal that non-Hispanic Whites have a significantly greater likelihood of residing in a flood zone when compared to Hispanic immigrants. These divergent results suggest that human-flood hazard relationships have been structured differently between the two MSAs, possibly due to the contrasting role that water-based amenities have played in urbanization within the two study areas. Future EJ research and practice should differentiate between Hispanic subgroups based on nativity status and attend to contextual factors influencing environmental risk disparities. PMID:27490561

Collaborative GIS for flood susceptibility mapping: An example from Mekong river basin of Viet Nam

NASA Astrophysics Data System (ADS)

Thanh, B.

2016-12-01

Flooding is one of the most dangerous natural disasters in Vietnam. Floods have caused serious damages to people and made adverse impact on social economic development across the country, especially in lower river basin where there is high risk of flooding as consequences of the climate change and social activities. This paper presents a collaborative platform of a combination of an interactive web-GIS framework and a multi-criteria evaluation (MCE) tool. MCE is carried out in server side through web interface, in which parameters used for evaluation are groups into three major categories, including (1) climatic factor: precipitation, typhoon frequency, temperature, humidity (2) physiographic data: DEM, topographic wetness index, NDVI, stream power index, soil texture, distance to river (3) social factor: NDBI, land use pattern. Web-based GIS is based on open-source technology that includes an information page, a page for MCE tool that users can interactively alter parameters in flood susceptible mapping, and a discussion page. The system is designed for local participation in prediction of the flood risk magnitude under impacts of natural processes and human intervention. The proposed flood susceptibility assessment prototype was implemented in the Mekong river basin, Viet Nam. Index images were calculated using Landsat data, and other were collected from authorized agencies. This study shows the potential to combine web-GIS and spatial analysis tool to flood hazard risk assessment. The combination can be a supportive solution that potentially assists the interaction between stakeholders in information exchange and in disaster management, thus provides for better analysis, control and decision-making.

Exposure to Flood Hazards in Miami and Houston: Are Hispanic Immigrants at Greater Risk than Other Social Groups?

PubMed

Maldonado, Alejandra; Collins, Timothy W; Grineski, Sara E; Chakraborty, Jayajit

2016-08-01

Although numerous studies have been conducted on the vulnerability of marginalized groups in the environmental justice (EJ) and hazards fields, analysts have tended to lump people together in broad racial/ethnic categories without regard for substantial within-group heterogeneity. This paper addresses that limitation by examining whether Hispanic immigrants are disproportionately exposed to risks from flood hazards relative to other racial/ethnic groups (including US-born Hispanics), adjusting for relevant covariates. Survey data were collected for 1283 adult householders in the Houston and Miami Metropolitan Statistical Areas (MSAs) and flood risk was estimated using their residential presence/absence within federally-designated 100-year flood zones. Generalized estimating equations (GEE) with binary logistic specifications that adjust for county-level clustering were used to analyze (separately) and compare the Houston (N = 546) and Miami (N = 560) MSAs in order to clarify determinants of household exposure to flood risk. GEE results in Houston indicate that Hispanic immigrants have the greatest likelihood, and non-Hispanic Whites the least likelihood, of residing in a 100-year flood zone. Miami GEE results contrastingly reveal that non-Hispanic Whites have a significantly greater likelihood of residing in a flood zone when compared to Hispanic immigrants. These divergent results suggest that human-flood hazard relationships have been structured differently between the two MSAs, possibly due to the contrasting role that water-based amenities have played in urbanization within the two study areas. Future EJ research and practice should differentiate between Hispanic subgroups based on nativity status and attend to contextual factors influencing environmental risk disparities.

Rainfall and runoff Intensity-Duration-Frequency Curves for Washington State considering the change and uncertainty of observed and anticipated extreme rainfall and snow events

NASA Astrophysics Data System (ADS)

Demissie, Y. K.; Mortuza, M. R.; Li, H. Y.

2015-12-01

The observed and anticipated increasing trends in extreme storm magnitude and frequency, as well as the associated flooding risk in the Pacific Northwest highlighted the need for revising and updating the local intensity-duration-frequency (IDF) curves, which are commonly used for designing critical water infrastructure. In Washington State, much of the drainage system installed in the last several decades uses IDF curves that are outdated by as much as half a century, making the system inadequate and vulnerable for flooding as seen more frequently in recent years. In this study, we have developed new and forward looking rainfall and runoff IDF curves for each county in Washington State using recently observed and projected precipitation data. Regional frequency analysis coupled with Bayesian uncertainty quantification and model averaging methods were used to developed and update the rainfall IDF curves, which were then used in watershed and snow models to develop the runoff IDF curves that explicitly account for effects of snow and drainage characteristic into the IDF curves and related designs. The resulted rainfall and runoff IDF curves provide more reliable, forward looking, and spatially resolved characteristics of storm events that can assist local decision makers and engineers to thoroughly review and/or update the current design standards for urban and rural storm water management infrastructure in order to reduce the potential ramifications of increasing severe storms and resulting floods on existing and planned storm drainage and flood management systems in the state.

Flood effects on an Alaskan stream restoration project: the value of long-term monitoring

USGS Publications Warehouse

Densmore, Roseann V.; Karle, Kenneth F.

2009-01-01

On a nationwide basis, few stream restoration projects have long-term programs in place to monitor the effects of floods on channel and floodplain configuration and floodplain vegetation, but long-term and event-based monitoring is required to measure the effects of these stochastic events and to use the knowledge for adaptive management and the design of future projects. This paper describes a long-term monitoring effort (15 years) on a stream restoration project in Glen Creek in Denali National Park and Preserve in Alaska. The stream channel and floodplain of Glen Creek had been severely degraded over a period of 80 years by placer mining for gold, which left many reaches with unstable and incised streambeds without functioning vegetated floodplains. The objectives of the original project, initiated in 1991, were to develop and test methods for the hydraulic design of channel and floodplain morphology and for floodplain stabilization and riparian habitat recovery, and to conduct research and monitoring to provide information for future projects in similar degraded watersheds. Monitoring methods included surveyed stream cross-sections, vegetation plots, and aerial, ground, and satellite photos. In this paper we address the immediate and outlying effects of a 25-year flood on the stream and floodplain geometry and riparian vegetation. The long-term monitoring revealed that significant channel widening occurred following the flood, likely caused by excessive upstream sediment loading and the fairly slow development of floodplain vegetation in this climate. Our results illustrated design flaws, particularly in regard to identification and analysis of sediment sources and the dominant processes of channel adjustment.

A Bivariate return period for levee failure monitoring

NASA Astrophysics Data System (ADS)

Isola, M.; Caporali, E.

2017-12-01

Levee breaches are strongly linked with the interaction processes among water, soil and structure, thus many are the factors that affect the breach development. One of the main is the hydraulic load, characterized by intensity and duration, i.e. by the flood event hydrograph. On the magnitude of the hydraulic load is based the levee design, generally without considering the fatigue failure due to the load duration. Moreover, many are the cases in which the levee breach are characterized by flood of magnitude lower than the design one. In order to implement the strategies of flood risk management, we built here a procedure based on a multivariate statistical analysis of flood peak and volume together with the analysis of the past levee failure events. Particularly, in order to define the probability of occurrence of the hydraulic load on a levee, a bivariate copula model is used to obtain the bivariate joint distribution of flood peak and volume. Flood peak is the expression of the load magnitude, while the volume is the expression of the stress over time. We consider the annual flood peak and the relative volume. The volume is given by the hydrograph area between the beginning and the end of event. The beginning of the event is identified as an abrupt rise of the discharge by more than 20%. The end is identified as the point from which the receding limb is characterized by the baseflow, using a nonlinear reservoir algorithm as baseflow separation technique. By this, with the aim to define warning thresholds we consider the past levee failure events and the relative bivariate return period (BTr) compared with the estimation of a traditional univariate model. The discharge data of 30 hydrometric stations of Arno River in Tuscany, Italy, in the period 1995-2016 are analysed. The database of levee failure events, considering for each event the location as well as the failure mode, is also created. The events were registered in the period 2000-2014 by EEA-Europe Environment Agency, the Italian Civil Protection and ISPRA (the Italian National Institute for Environmental Protection and Research). Only two levee failures events occurred in the sub-basin of Era River have been detected and analysed. The estimated return period with the univariate model of flood peak is greater than 2 and 5 years while the BTr is greater of 25 and 30 years respectively.

Bathymetric survey of the Cayuga Inlet flood-control channel and selected tributaries in Ithaca, New York, 2016

USGS Publications Warehouse

Wernly, John F.; Nystrom, Elizabeth A.; Coon, William F.

2017-09-08

From July 14 to July 20, 2016, the U.S. Geological Survey, in cooperation with the City of Ithaca, New York, and the New York State Department of State, surveyed the bathymetry of the Cayuga Inlet flood-control channel and the mouths of selected tributaries to Cayuga Inlet and Cayuga Lake in Ithaca, N.Y. The flood-control channel, built by the U.S. Army Corps of Engineers between 1965 and 1970, was designed to convey flood flows from the Cayuga Inlet watershed through the City of Ithaca and minimize possible flood damages. Since that time, the channel has infrequently been maintained by dredging, and sediment accumulation and resultant shoaling have greatly decreased the conveyance of the channel and its navigational capability.U.S. Geological Survey personnel collected bathymetric data by using an acoustic Doppler current profiler. The survey produced a dense dataset of water depths that were converted to bottom elevations. These elevations were then used to generate a geographic information system bathymetric surface. The bathymetric data and resultant bathymetric surface show the current condition of the channel and provide the information that governmental agencies charged with maintaining the Cayuga Inlet for flood-control and navigational purposes need to make informed decisions regarding future maintenance measures.

Association between Floods and Acute Cardiovascular Diseases: A Population-Based Cohort Study Using a Geographic Information System Approach

PubMed Central

Vanasse, Alain; Cohen, Alan; Courteau, Josiane; Bergeron, Patrick; Dault, Roxanne; Gosselin, Pierre; Blais, Claudia; Bélanger, Diane; Rochette, Louis; Chebana, Fateh

2016-01-01

Background: Floods represent a serious threat to human health beyond the immediate risk of drowning. There is few data on the potential link between floods and direct consequences on health such as on cardiovascular health. This study aimed to explore the impact of one of the worst floods in the history of Quebec, Canada on acute cardiovascular diseases (CVD). Methods: A cohort study with a time series design with multiple control groups was built with the adult population identified in the Quebec Integrated Chronic Disease Surveillance System. A geographic information system approach was used to define the study areas. Logistic regressions were performed to compare the occurrence of CVD between groups. Results: The results showed a 25%–27% increase in the odds in the flooded population in spring 2011 when compared with the population in the same area in springs 2010 and 2012. Besides, an increase up to 69% was observed in individuals with a medical history of CVD. Conclusion: Despite interesting results, the association was not statistically significant. A possible explanation to this result can be that the population affected by the flood was probably too small to provide the statistical power to answer the question, and leaves open a substantial possibility for a real and large effect. PMID:26828511

Association between Floods and Acute Cardiovascular Diseases: A Population-Based Cohort Study Using a Geographic Information System Approach.

PubMed

Vanasse, Alain; Cohen, Alan; Courteau, Josiane; Bergeron, Patrick; Dault, Roxanne; Gosselin, Pierre; Blais, Claudia; Bélanger, Diane; Rochette, Louis; Chebana, Fateh

2016-01-28

Floods represent a serious threat to human health beyond the immediate risk of drowning. There is few data on the potential link between floods and direct consequences on health such as on cardiovascular health. This study aimed to explore the impact of one of the worst floods in the history of Quebec, Canada on acute cardiovascular diseases (CVD). A cohort study with a time series design with multiple control groups was built with the adult population identified in the Quebec Integrated Chronic Disease Surveillance System. A geographic information system approach was used to define the study areas. Logistic regressions were performed to compare the occurrence of CVD between groups. The results showed a 25%-27% increase in the odds in the flooded population in spring 2011 when compared with the population in the same area in springs 2010 and 2012. Besides, an increase up to 69% was observed in individuals with a medical history of CVD. Despite interesting results, the association was not statistically significant. A possible explanation to this result can be that the population affected by the flood was probably too small to provide the statistical power to answer the question, and leaves open a substantial possibility for a real and large effect.

Application of a distributed hydrological model to the design of a road inundation warning system for flash flood prone areas

NASA Astrophysics Data System (ADS)

Versini, P.-A.; Gaume, E.; Andrieu, H.

2010-04-01

This paper presents an initial prototype of a distributed hydrological model used to map possible road inundations in a region frequently exposed to severe flash floods: the Gard region (South of France). The prototype has been tested in a pseudo real-time mode on five recent flash flood events for which actual road inundations have been inventoried. The results are promising: close to 100% probability of detection of actual inundations, inundations detected before they were reported by the road management field teams with a false alarm ratios not exceeding 30%. This specific case study differs from the standard applications of rainfall-runoff models to produce flood forecasts, focussed on a single or a limited number of gauged river cross sections. It illustrates that, despite their lack of accuracy, hydro-meteorological forecasts based on rainfall-runoff models, especially distributed models, contain valuable information for flood event management. The possible consequences of landslides, debris flows and local erosion processes, sometimes associated with flash floods, were not considered at this stage of development of the prototype. They are limited in the Gard region but should be taken into account in future developments of the approach to implement it efficiently in other areas more exposed to these phenomena such as the Alpine area.

Self-Organization of Microscale Condensate for Delayed Flooding of Nanostructured Superhydrophobic Surfaces.

PubMed

Ölçeroğlu, Emre; McCarthy, Matthew

2016-03-02

Superhydrophobic surfaces enhance condensation by inhibiting the formation of an insulating liquid layer. While this produces efficient heat transfer at low supersaturations, superhydrophobicity has been shown to break down at increased supersaturations. As heat transfer increases, the random distribution and high density of nucleation sites produces pinned droplets, which lead to uncontrollable flooding. In this work, engineered variations in wettability are used to promote the self-organization of microscale droplets, which is shown to effectively delay flooding. Virus-templated superhydrophobic surfaces are patterned with an array of superhydrophilic islands designed to minimize surface adhesion while promoting spatial order. By use of optical and electron microscopy, the surfaces are optimized and characterized during condensation. Mixed wettability imparts spatial order not only through preferential nucleation but more importantly through the self-organization of coalescing droplets at high supersaturations. The self-organization of microscale droplets (diameters of <25 μm) is shown to effectively delay flooding and govern the global wetting behavior of larger droplets (diameters of >1 mm) on the surface. As heat transfer increases, the surfaces transition from jumping-mode to shedding-mode removal with no flooding. This demonstrates the ability to engineer surfaces to resist flooding and can act as the basis for developing robust superhydrophobic surfaces for condensation applications.

Flood prevention dams for arid regions at a micro-scale sub-catchment, case study: Tabuk, Saudi Arabia.

PubMed

Abushandi, Eyad

2016-12-01

Unexpected flash flooding is one of the periodic hydrological problems affecting the city of Tabuk in Saudi Arabia. The region has high potential for floods as it suffers high rainfall intensity in a short time and also has high urbanization rates and topographic complexity. Constructing flood prevention dams is one option to solve this problem. A cost-effective design requires a detailed feasibility study and analysis for the selection of suitable sites. The aim of this study was to develop a method for selecting a suitable site for flood protection dams in the Abu Saba'a district, the most affected part of the city of Tabuk during the flash flood in January 2013. Spatial analysis was applied using Landsat Thematic Mapper images and Shuttle Radar Topography Mission digital elevation model to select a site in the Abu Saba'a area. A simple model using ArcGIS was built including all suggested parameters. The results showed the best site for a dam was 2 km distance backfrom the area, where all parameter values matched. The results showed that the dynamic properties of land cover can affect site selection. It is therefore suggested that more field and hydrological data should be gathered for greater accuracy.

Assessing the performance of multi-purpose channel management measures at increasing scales

NASA Astrophysics Data System (ADS)

Wilkinson, Mark; Addy, Steve

2016-04-01

In addition to hydroclimatic drivers, sediment deposition from high energy river systems can reduce channel conveyance capacity and lead to significant increases in flood risk. There is an increasing recognition that we need to work with the interplay of natural hydrological and morphological processes in order to attenuate flood flows and manage sediment (both coarse and fine). This typically includes both catchment (e.g. woodland planting, wetlands) and river (e.g. wood placement, floodplain reconnection) restoration approaches. The aim of this work was to assess at which scales channel management measures (notably wood placement and flood embankment removal) are most appropriate for flood and sediment management in high energy upland river systems. We present research findings from two densely instrumented research sites in Scotland which regularly experience flood events and have associated coarse sediment problems. We assessed the performance of a range of novel trial measures for three different scales: wooded flow restrictors and gully tree planting at the small scale (<1 km2), floodplain tree planting and engineered log jams at the intermediate scale (5-60 km2), and flood embankment lowering at the large scale (350 km2). Our results suggest that at the smallest scale, care is needed in the installation of flow restrictors. It was found for some restrictors that vertical erosion can occur if the tributary channel bed is disturbed. Preliminary model evidence suggested they have a very limited impact on channel discharge and flood peak delay owing to the small storage areas behind the structures. At intermediate scales, the ability to trap sediment by engineered log jams was limited. Of the 45 engineered log jams installed, around half created a small geomorphic response and only 5 captured a significant amount of coarse material (during one large flood event). As scale increases, the chance of damage or loss of wood placement is greatest. Monitoring highlights the importance of structure design (porosity and degree of channel blockage) and placement in zones of high sediment transport to optimise performance. At the large scale, well designed flood embankment lowering can improve connectivity to the floodplain during low to medium return period events. However, ancillary works to stabilise the bank failed thus emphasising the importance of letting natural processes readjust channel morphology and hydrological connections to the floodplain. Although these trial measures demonstrated limited effects, this may be in part owing to restrictions in the range of hydroclimatological conditions during the study period and further work is needed to assess the performance under more extreme conditions. This work will contribute to refining guidance for managing channel coarse sediment problems in the future which in turn could help mitigate flooding using natural approaches.

A Fresh Start for Flood Estimation in Ungauged Basins

NASA Astrophysics Data System (ADS)

Woods, R. A.

2017-12-01

The two standard methods for flood estimation in ungauged basins, regression-based statistical models and rainfall-runoff models using a design rainfall event, have survived relatively unchanged as the methods of choice for more than 40 years. Their technical implementation has developed greatly, but the models' representation of hydrological processes has not, despite a large volume of hydrological research. I suggest it is time to introduce more hydrology into flood estimation. The reliability of the current methods can be unsatisfactory. For example, despite the UK's relatively straightforward hydrology, regression estimates of the index flood are uncertain by +/- a factor of two (for a 95% confidence interval), an impractically large uncertainty for design. The standard error of rainfall-runoff model estimates is not usually known, but available assessments indicate poorer reliability than statistical methods. There is a practical need for improved reliability in flood estimation. Two promising candidates to supersede the existing methods are (i) continuous simulation by rainfall-runoff modelling and (ii) event-based derived distribution methods. The main challenge with continuous simulation methods in ungauged basins is to specify the model structure and parameter values, when calibration data are not available. This has been an active area of research for more than a decade, and this activity is likely to continue. The major challenges for the derived distribution method in ungauged catchments include not only the correct specification of model structure and parameter values, but also antecedent conditions (e.g. seasonal soil water balance). However, a much smaller community of researchers are active in developing or applying the derived distribution approach, and as a result slower progress is being made. A change in needed: surely we have learned enough about hydrology in the last 40 years that we can make a practical hydrological advance on our methods for flood estimation! A shift to new methods for flood estimation will not be taken lightly by practitioners. However, the standard for change is clear - can we develop new methods which give significant improvements in reliability over those existing methods which are demonstrably unsatisfactory?

Flood-hazard mapping in Honduras in response to Hurricane Mitch

USGS Publications Warehouse

Mastin, M.C.

2002-01-01

The devastation in Honduras due to flooding from Hurricane Mitch in 1998 prompted the U.S. Agency for International Development, through the U.S. Geological Survey, to develop a country-wide systematic approach of flood-hazard mapping and a demonstration of the method at selected sites as part of a reconstruction effort. The design discharge chosen for flood-hazard mapping was the flood with an average return interval of 50 years, and this selection was based on discussions with the U.S. Agency for International Development and the Honduran Public Works and Transportation Ministry. A regression equation for estimating the 50-year flood discharge using drainage area and annual precipitation as the explanatory variables was developed, based on data from 34 long-term gaging sites. This equation, which has a standard error of prediction of 71.3 percent, was used in a geographic information system to estimate the 50-year flood discharge at any location for any river in the country. The flood-hazard mapping method was demonstrated at 15 selected municipalities. High-resolution digital-elevation models of the floodplain were obtained using an airborne laser-terrain mapping system. Field verification of the digital elevation models showed that the digital-elevation models had mean absolute errors ranging from -0.57 to 0.14 meter in the vertical dimension. From these models, water-surface elevation cross sections were obtained and used in a numerical, one-dimensional, steady-flow stepbackwater model to estimate water-surface profiles corresponding to the 50-year flood discharge. From these water-surface profiles, maps of area and depth of inundation were created at the 13 of the 15 selected municipalities. At La Lima only, the area and depth of inundation of the channel capacity in the city was mapped. At Santa Rose de Aguan, no numerical model was created. The 50-year flood and the maps of area and depth of inundation are based on the estimated 50-year storm tide.

Tacking Flood Risk from Watersheds using a Natural Flood Risk Management Toolkit

NASA Astrophysics Data System (ADS)

Reaney, S. M.; Pearson, C.; Barber, N.; Fraser, A.

2017-12-01

In the UK, flood risk management is moving beyond solely mitigating at the point of impact in towns and key infrastructure to tackle problem at source through a range of landscape based intervention measures. This natural flood risk management (NFM) approach has been trailed within a range of catchments in the UK and is moving towards being adopted as a key part of flood risk management. The approach offers advantages including lower cost and co-benefits for water quality and habitat creation. However, for an agency or group wishing to implement NFM within a catchment, there are two key questions that need to be addressed: Where in the catchment to place the measures? And how many measures are needed to be effective? With this toolkit, these questions are assessed with a two-stage workflow. First, SCIMAP-Flood gives a risk based mapping of likely locations that contribute to the flood peak. This tool uses information on land cover, hydrological connectivity, flood generating rainfall patterns and hydrological travel time distributions to impacted communities. The presented example applies the tool to the River Eden catchment, UK, with 5m grid resolution and hence provide sub-field scale information at the landscape extent. SCIMAP-Flood identifies sub-catchments where physically based catchment hydrological simulation models can be applied to test different NFM based mitigation measures. In this example, the CRUM3 catchment hydrological model has been applied within an uncertainty framework to consider the effectiveness of soil compaction reduction and large woody debris dams within a sub-catchment. It was found that large scale soil aeration to reduce soil compaction levels throughout the catchment is probably the most useful natural flood management measure for this catchment. NFM has potential for wide-spread application and these tools help to ensure that the measures are correctly designed and the scheme performance can be quantitatively assessed and predicted.

A Database of Historical Information on Landslides and Floods in Italy

NASA Astrophysics Data System (ADS)

Guzzetti, F.; Tonelli, G.

2003-04-01

For the past 12 years we have maintained and updated a database of historical information on landslides and floods in Italy, known as the National Research Council's AVI (Damaged Urban Areas) Project archive. The database was originally designed to respond to a specific request of the Minister of Civil Protection, and was aimed at helping the regional assessment of landslide and flood risk in Italy. The database was first constructed in 1991-92 to cover the period 1917 to 1990. Information of damaging landslide and flood event was collected by searching archives, by screening thousands of newspaper issues, by reviewing the existing technical and scientific literature on landslides and floods in Italy, and by interviewing landslide and flood experts. The database was then updated chiefly through the analysis of hundreds of newspaper articles, and it now covers systematically the period 1900 to 1998, and non-systematically the periods 1900 to 1916 and 1999 to 2002. Non systematic information on landslide and flood events older than 20th century is also present in the database. The database currently contains information on more than 32,000 landslide events occurred at more than 25,700 sites, and on more than 28,800 flood events occurred at more than 15,600 sites. After a brief outline of the history and evolution of the AVI Project archive, we present and discuss: (a) the present structure of the database, including the hardware and software solutions adopted to maintain, manage, use and disseminate the information stored in the database, (b) the type and amount of information stored in the database, including an estimate of its completeness, and (c) examples of recent applications of the database, including a web-based GIS systems to show the location of sites historically affected by landslides and floods, and an estimate of geo-hydrological (i.e., landslide and flood) risk in Italy based on the available historical information.

Hydraulics of outburst floods spilling over a steep-walled canyon: Implications for paleo-discharges on Mars

NASA Astrophysics Data System (ADS)

Lapotre, Mathieu; Lamb, Michael

2013-04-01

Canyons carved by outburst floods are common landforms on Earth and Mars. These canyons are generally found in fractured basalts and jointed sedimentary rocks. Flood-carved canyons commonly have steep headwalls and a roughly constant width, and are often thought to have formed from upstream headwall propagation due to waterfall erosion. Because morphology is readily available from satellite imagery, these canyons offer a unique opportunity to quantify the discharge of rare, catastrophic paleo-floods on Earth and Mars. However, mechanistic relationships that relate canyon size to flood discharge have yet to be developed. We propose that the width of a canyon headwall in fractured rock is set by the spatial distribution of erosion around the rim of the canyon, which is controlled by the distribution of shear stresses induced by the overflowing water as it is focused into the canyon head. We test this hypothesis by performing a series of numerical simulations of flood-water focusing using ANUGA Hydro, a 2D-depth averaged, fully turbulent, hydraulic numerical modeling suite allowing for Froude-number transitions. The numerical simulations were designed to explore five dimensionless variables: the aspect ratio of the canyon (length normalized by width), the canyon width to flood-water width ratio, the canyon width to normal-flow depth ratio, the Froude number, and the topographic gradient upstream of the canyon. Preliminary results show that flow focusing leads to increased shear stresses at the canyon head compared to the sides of the canyon for subcritical floods and higher canyon aspect ratios. This suggests that proto-canyons start growing from a topographic defect in all directions until they reach a critical length for the side walls to dry. Once this critical length is attained, canyons focus most of the flood waters into their heads, and propagate upstream only, maintaining roughly constant widths. Preliminary results suggest that canyon width may be used to reconstruct the discharge of paleo-flood events on Mars and Earth.

Do regional methods really help reduce uncertainties in flood frequency analyses?

NASA Astrophysics Data System (ADS)

Cong Nguyen, Chi; Payrastre, Olivier; Gaume, Eric

2013-04-01

Flood frequency analyses are often based on continuous measured series at gauge sites. However, the length of the available data sets is usually too short to provide reliable estimates of extreme design floods. To reduce the estimation uncertainties, the analyzed data sets have to be extended either in time, making use of historical and paleoflood data, or in space, merging data sets considered as statistically homogeneous to build large regional data samples. Nevertheless, the advantage of the regional analyses, the important increase of the size of the studied data sets, may be counterbalanced by the possible heterogeneities of the merged sets. The application and comparison of four different flood frequency analysis methods to two regions affected by flash floods in the south of France (Ardèche and Var) illustrates how this balance between the number of records and possible heterogeneities plays in real-world applications. The four tested methods are: (1) a local statistical analysis based on the existing series of measured discharges, (2) a local analysis valuating the existing information on historical floods, (3) a standard regional flood frequency analysis based on existing measured series at gauged sites and (4) a modified regional analysis including estimated extreme peak discharges at ungauged sites. Monte Carlo simulations are conducted to simulate a large number of discharge series with characteristics similar to the observed ones (type of statistical distributions, number of sites and records) to evaluate to which extent the results obtained on these case studies can be generalized. These two case studies indicate that even small statistical heterogeneities, which are not detected by the standard homogeneity tests implemented in regional flood frequency studies, may drastically limit the usefulness of such approaches. On the other hand, these result show that the valuation of information on extreme events, either historical flood events at gauged sites or estimated extremes at ungauged sites in the considered region, is an efficient way to reduce uncertainties in flood frequency studies.

Surfactant-Enhanced Aquifer Remediation (SEAR) Implementation Manual

DTIC Science & Technology

2003-04-01

UTCHEM University of Texas Chemical Flooding Simulator VOC volatile organic compound wt% weight percent iv Section 1.0: INTRODUCTION 1.1...proper sample spacing that captures the peak breakthrough curve and tailing concentrations caused by post- surfactant water flooding. UTCHEM design...90 100 110 120 130 140 Time Since Surf. Injection, days D iss ol ve d PC E C on c. , m g/ l Field data UTCHEM (Run ISA26m) End of surfactant

Guidelines for determining flood flow frequency—Bulletin 17C

USGS Publications Warehouse

England, John F.; Cohn, Timothy A.; Faber, Beth A.; Stedinger, Jery R.; Thomas, Wilbert O.; Veilleux, Andrea G.; Kiang, Julie E.; Mason, Robert R.

2018-03-29

Accurate estimates of flood frequency and magnitude are a key component of any effective nationwide flood risk management and flood damage abatement program. In addition to accuracy, methods for estimating flood risk must be uniformly and consistently applied because management of the Nation’s water and related land resources is a collaborative effort involving multiple actors including most levels of government and the private sector.Flood frequency guidelines have been published in the United States since 1967, and have undergone periodic revisions. In 1967, the U.S. Water Resources Council presented a coherent approach to flood frequency with Bulletin 15, “A Uniform Technique for Determining Flood Flow Frequencies.” The method it recommended involved fitting the log-Pearson Type III distribution to annual peak flow data by the method of moments.The first extension and update of Bulletin 15 was published in 1976 as Bulletin 17, “Guidelines for Determining Flood Flow Frequency” (Guidelines). It extended the Bulletin 15 procedures by introducing methods for dealing with outliers, historical flood information, and regional skew. Bulletin 17A was published the following year to clarify the computation of weighted skew. The next revision of the Bulletin, the Bulletin 17B, provided a host of improvements and new techniques designed to address situations that often arise in practice, including better methods for estimating and using regional skew, weighting station and regional skew, detection of outliers, and use of the conditional probability adjustment.The current version of these Guidelines are presented in this document, denoted Bulletin 17C. It incorporates changes motivated by four of the items listed as “Future Work” in Bulletin 17B and 30 years of post-17B research on flood processes and statistical methods. The updates include: adoption of a generalized representation of flood data that allows for interval and censored data types; a new method, called the Expected Moments Algorithm, which extends the method of moments so that it can accommodate interval data; a generalized approach to identification of low outliers in flood data; and an improved method for computing confidence intervals.Federal agencies are requested to use these Guidelines in all planning activities involving water and related land resources. State, local, and private organizations are encouraged to use these Guidelines to assure uniformity in the flood frequency estimates that all agencies concerned with flood risk should use for Federal planning decisions.This revision is adopted with the knowledge and understanding that review of these procedures will be ongoing. Updated methods will be adopted when warranted by experience and by examination and testing of new techniques.

Flood model for Brazil

NASA Astrophysics Data System (ADS)

Palán, Ladislav; Punčochář, Petr

2017-04-01

Looking on the impact of flooding from the World-wide perspective, in last 50 years flooding has caused over 460,000 fatalities and caused serious material damage. Combining economic loss from ten costliest flood events (from the same period) returns a loss (in the present value) exceeding 300bn USD. Locally, in Brazil, flood is the most damaging natural peril with alarming increase of events frequencies as 5 out of the 10 biggest flood losses ever recorded have occurred after 2009. The amount of economic and insured losses particularly caused by various flood types was the key driver of the local probabilistic flood model development. Considering the area of Brazil (being 5th biggest country in the World) and the scattered distribution of insured exposure, a domain covered by the model was limited to the entire state of Sao Paolo and 53 additional regions. The model quantifies losses on approx. 90 % of exposure (for regular property lines) of key insurers. Based on detailed exposure analysis, Impact Forecasting has developed this tool using long term local hydrological data series (Agencia Nacional de Aguas) from riverine gauge stations and digital elevation model (Instituto Brasileiro de Geografia e Estatística). To provide most accurate representation of local hydrological behaviour needed for the nature of probabilistic simulation, a hydrological data processing focused on frequency analyses of seasonal peak flows - done by fitting appropriate extreme value statistical distribution and stochastic event set generation consisting of synthetically derived flood events respecting realistic spatial and frequency patterns visible in entire period of hydrological observation. Data were tested for homogeneity, consistency and for any significant breakpoint occurrence in time series so the entire observation or only its subparts were used for further analysis. The realistic spatial patterns of stochastic events are reproduced through the innovative use of d-vine copula scheme to generate probabilistic flood event set. The derived design flows for selected rivers inside model domain were used as an input for 2-dimensional hydrodynamic inundation modelling techniques (using the tool TUFLOW by BMT WBM) on mesh size 30 x 30 metres. Outputs from inundation modelling and stochastic event set were implemented in the Aon Benfield's platform ELEMENTS developed and managed internally by Impact Forecasting; Aon Benfield internal catastrophe model development center. The model was designed to evaluate potential financial impact caused by fluvial flooding on portfolios of insurance and/or reinsurance companies. The structure of presented model follows typical scheme of financial loss catastrophe model and combines hazard with exposure and vulnerability to produce potential financial loss expressed in the form of loss exceedance probability curve and many other insured perspectives, such as average annual loss, event or quantile loss tables and etc. Model can take financial inputs as well as provide split of results for exact specified location or related higher administrative units: municipalities and 5-digit postal codes.

23 CFR 650.115 - Design standards.

Code of Federal Regulations, 2014 CFR

2014-04-01

..., STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains § 650.115 Design... a regulatory floodway. (b) Rest area buildings and related water supply and waste treatment... highway fills are to be used as dams to permanently impound water more than 50 acre-feet (6.17×104 cubic...

23 CFR 650.115 - Design standards.

Code of Federal Regulations, 2013 CFR

2013-04-01

..., STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains § 650.115 Design... a regulatory floodway. (b) Rest area buildings and related water supply and waste treatment... highway fills are to be used as dams to permanently impound water more than 50 acre-feet (6.17×104 cubic...

23 CFR 650.115 - Design standards.

Code of Federal Regulations, 2012 CFR

2012-04-01

..., STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains § 650.115 Design... a regulatory floodway. (b) Rest area buildings and related water supply and waste treatment... highway fills are to be used as dams to permanently impound water more than 50 acre-feet (6.17×104 cubic...

23 CFR 650.115 - Design standards.

Code of Federal Regulations, 2010 CFR

2010-04-01

..., STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains § 650.115 Design... a regulatory floodway. (b) Rest area buildings and related water supply and waste treatment... highway fills are to be used as dams to permanently impound water more than 50 acre-feet (6.17×104 cubic...

23 CFR 650.115 - Design standards.

Code of Federal Regulations, 2011 CFR

2011-04-01

..., STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains § 650.115 Design... a regulatory floodway. (b) Rest area buildings and related water supply and waste treatment... highway fills are to be used as dams to permanently impound water more than 50 acre-feet (6.17×104 cubic...

Waverly, Iowa Smart Planning Workshop: Policy Options and Project Designs

EPA Pesticide Factsheets

This report from the EPA-FEMA technical assistance project in Waverly, IA, presents policy options and project design ideas that could help new development be more resilient to disasters such as floods while bringing multiple benefits.

Perception of flood and landslide risk in Italy: a preliminary analysis

NASA Astrophysics Data System (ADS)

Salvati, P.; Bianchi, C.; Fiorucci, F.; Giostrella, P.; Marchesini, I.; Guzzetti, F.

2014-05-01

Inundations and landslides are widespread phenomena in Italy, where they cause severe damage and pose a threat to the population. Little is known on the perception of the population of landslides and floods. This is surprising, as an accurate perception is important for the successful implementation of many risk reduction or adaptation strategies. In an attempt to fill this gap, we have conducted two national surveys to measure the perception of landslide and flood risk of the population of Italy. The surveys were executed in 2012 and 2013, performing for each survey approximately 3100 computer assisted telephone interviews. The samples of the interviewees were statistically representative for a national scale quantitative assessment. The interviewees were asked questions designed to obtain information on their: (i) perception of natural, environmental, and technological risks, (ii) direct experience or general knowledge on the occurrence of landslides and floods in their municipality, (iii) perception of the possible threat posed by landslides and floods to their safety, (iv) general knowledge on the number of victims caused by landslides or floods, and on (v) the factors that they considered important to control landslide and flood risks in Italy. The surveys revealed that the population of Italy fears technological risks more than natural risks. Of the natural risks, earthquakes were considered more dangerous than floods, landslides, and volcanic eruptions. Examination of the temporal and geographical distribution of the responses revealed that the occurrence of recent damaging events influenced risk perception locally, and that the perception persisted longer for earthquakes and decreased more rapidly for landslides and floods. We justify the differentiation with the diverse consequences of the risks. The interviewees considered inappropriate land management the main cause of landslide and flood risk, followed by illegal construction, abandonment of the territory, and climate change. Comparison of the risk perception with actual measures of landslide and flood risk, including the number of fatal events, the number of fatalities, and the mortality rates, revealed that in most of the Italian regions the perception of the threat did not match the long-term risk posed by landslides and floods to the population. This outcome points to the need to fostering the understanding of the population of landslide and flood hazards and risks in Italy.

WMO's activities in gender mainstreaming in geosciences, with a special focus on integrated flood management

NASA Astrophysics Data System (ADS)

Manaenkova, Elena; Caponi, Claudio; Alexieva, Assia; Poissonnier, Maud; Tripathi, Ramesh

2017-04-01

Statistics show that women represent a minority in science, technology, engineering and mathematics (STEM). They are significantly underrepresented in governance, management and international negotiations. They further comprise only a third of the global workforce at National Meteorological and Hydrological Services and only one out of five senior managers is a woman. This paper presents historical trends and statistics on the participation of women and men in all structures and activities of the World Meteorological Organization (WMO). It explores the root causes of women's underrepresentation in the meteorological, hydrological and climatological profession as well as analyzes its adverse effects in terms of the scarcity of role models for young female professionals and the lack of gender considerations in the provision of weather, hydrological and climate services. The paper presents WMO's approach to addressing these issues through the adoption of a WMO Gender Equality Policy, a comprehensive Gender Action Plan, targeted leadership training, a series of awareness raising campaigns, and specific recommendations on how to make weather, hydrological and climate services more gender-sensitive. As a specific example, the Associated Programme on Flood Management (APFM) of WMO and the Global Water Partnership (GWP) is in the process of developing a training manual for gender mainstreaming in integrated flood management. This generic, instructive, at the same time informative training manual and facilitator's guide will strive to fill gaps in practical knowledge, decision-making and further provide assistance in gender sensitive approaches for both local policy makers and communities affected by floods. The format and contents of the manual are particularly focused on every phase of the flood management cycle, incorporating gender based needs, strategies and actions/approaches. The facilitator or training instructor is encouraged to adapt the materials with local case studies for conducting short exercises with the intended participants (women and men) using a participatory design approach. Keywords: Meteorological, Hydrological, Climatological, Gender equality, Integrated flood management, Training manual, Participatory design

Investigation of Chemical-Foam Design as a Novel Approach toward Immiscible Foam Flooding for Enhanced Oil Recovery

PubMed Central

2017-01-01

Strong foam can be generated in porous media containing oil, resulting in incremental oil recovery; however, oil recovery factor is restricted. A large fraction of oil recovered by foam flooding forms an oil-in-water emulsion, so that costly methods may need to be used to separate the oil. Moreover, strong foam could create a large pressure gradient, which may cause fractures in the reservoir. This study presents a novel chemical-foam flooding process for enhanced oil recovery (EOR) from water-flooded reservoirs. The presented method involved the use of chemically designed foam to mobilize the remaining oil after water flooding and then to displace the mobilized oil to the production well. A blend of two anionic surfactant formulations was formulated for this method: (a) IOS, for achieving ultralow interfacial tension (IFT), and (b) AOS, for generating a strong foam. Experiments were performed using Bentheimer sandstone cores, where X-ray CT images were taken during foam generation to find the stability of the advancing front of foam propagation and to map the gas saturation for both the transient and the steady-state flow regimes. Then the proposed chemical-foam strategy for incremental oil recovery was tested through the coinjection of immiscible nitrogen gas and surfactant solutions with three different formulation properties in terms of IFT reduction and foaming strength capability. The discovered optimal formulation contains a foaming agent surfactant, a low IFT surfactant, and a cosolvent, which has a high foam stability and a considerably low IFT (1.6 × 10–2 mN/m). Coinjection resulted in higher oil recovery and much less MRF than the same process with only using a foaming agent. The oil displacement experiment revealed that coinjection of gas with a blend of surfactants, containing a cosolvent, can recover a significant amount of oil (33% OIIP) over water flooding with a larger amount of clean oil and less emulsion. PMID:29093612

Investigation of Chemical-Foam Design as a Novel Approach toward Immiscible Foam Flooding for Enhanced Oil Recovery.

PubMed

Hosseini-Nasab, S M; Zitha, P L J

2017-10-19

Strong foam can be generated in porous media containing oil, resulting in incremental oil recovery; however, oil recovery factor is restricted. A large fraction of oil recovered by foam flooding forms an oil-in-water emulsion, so that costly methods may need to be used to separate the oil. Moreover, strong foam could create a large pressure gradient, which may cause fractures in the reservoir. This study presents a novel chemical-foam flooding process for enhanced oil recovery (EOR) from water-flooded reservoirs. The presented method involved the use of chemically designed foam to mobilize the remaining oil after water flooding and then to displace the mobilized oil to the production well. A blend of two anionic surfactant formulations was formulated for this method: (a) IOS, for achieving ultralow interfacial tension (IFT), and (b) AOS, for generating a strong foam. Experiments were performed using Bentheimer sandstone cores, where X-ray CT images were taken during foam generation to find the stability of the advancing front of foam propagation and to map the gas saturation for both the transient and the steady-state flow regimes. Then the proposed chemical-foam strategy for incremental oil recovery was tested through the coinjection of immiscible nitrogen gas and surfactant solutions with three different formulation properties in terms of IFT reduction and foaming strength capability. The discovered optimal formulation contains a foaming agent surfactant, a low IFT surfactant, and a cosolvent, which has a high foam stability and a considerably low IFT (1.6 × 10 -2 mN/m). Coinjection resulted in higher oil recovery and much less MRF than the same process with only using a foaming agent. The oil displacement experiment revealed that coinjection of gas with a blend of surfactants, containing a cosolvent, can recover a significant amount of oil (33% OIIP) over water flooding with a larger amount of clean oil and less emulsion.

Integrating Hydrologic and Water Quality Models as a Decision Support Tool for Implementation of Low Impact Development in a Coastal Urban Watershed under Climate Variability and Sea Level Rise

NASA Astrophysics Data System (ADS)

Chang, N. B.

2016-12-01

Many countries concern about development and redevelopment efforts in urban regions to reduce the flood risk by considering hazards such as high-tide events, storm surge, flash floods, stormwater runoff, and impacts of sea level rise. Combining these present and future hazards with vulnerable characteristics found throughout coastal communities such as majority low-lying areas and increasing urban development, create scenarios for increasing exposure of flood hazard. As such, the most vulnerable areas require adaptation strategies and mitigation actions for flood hazard management. In addition, in the U.S., Numeric Nutrient Criteria (NNC) are a critical tool for protecting and restoring the designated uses of a waterbody with regard to nitrogen and phosphorus pollution. Strategies such as low impact development (LID) have been promoted in recent years as an alternative to traditional stormwater management and drainage to control both flooding and water quality impact. LID utilizes decentralized multifunctional site designs and incorporates on-site storm water management practices rather than conventional storm water management approaches that divert flow toward centralized facilities. How to integrate hydrologic and water quality models to achieve the decision support becomes a challenge. The Cross Bayou Watershed of Pinellas County in Tampa Bay, a highly urbanized coastal watershed, is utilized as a case study due to its sensitivity to flood hazards and water quality management within the watershed. This study will aid the County, as a decision maker, to implement its stormwater management policy and honor recent NNC state policy via demonstration of an integrated hydrologic and water quality model, including the Interconnected Channel and Pond Routing Model v.4 (ICPR4) and the BMPTRAIN model as a decision support tool. The ICPR4 can be further coupled with the ADCIRC/SWAN model to reflect the storm surge and seal level rise in coastal regions.

Estimating magnitude and frequency of floods using the PeakFQ 7.0 program

USGS Publications Warehouse

Veilleux, Andrea G.; Cohn, Timothy A.; Flynn, Kathleen M.; Mason, Jr., Robert R.; Hummel, Paul R.

2014-01-01

Flood-frequency analysis provides information about the magnitude and frequency of flood discharges based on records of annual maximum instantaneous peak discharges collected at streamgages. The information is essential for defining flood-hazard areas, for managing floodplains, and for designing bridges, culverts, dams, levees, and other flood-control structures. Bulletin 17B (B17B) of the Interagency Advisory Committee on Water Data (IACWD; 1982) codifies the standard methodology for conducting flood-frequency studies in the United States. B17B specifies that annual peak-flow data are to be fit to a log-Pearson Type III distribution. Specific methods are also prescribed for improving skew estimates using regional skew information, tests for high and low outliers, adjustments for low outliers and zero flows, and procedures for incorporating historical flood information. The authors of B17B identified various needs for methodological improvement and recommended additional study. In response to these needs, the Advisory Committee on Water Information (ACWI, successor to IACWD; http://acwi.gov/, Subcommittee on Hydrology (SOH), Hydrologic Frequency Analysis Work Group (HFAWG), has recommended modest changes to B17B. These changes include adoption of a generalized method-of-moments estimator denoted the Expected Moments Algorithm (EMA) (Cohn and others, 1997) and a generalized version of the Grubbs-Beck test for low outliers (Cohn and others, 2013). The SOH requested that the USGS implement these changes in a user-friendly, publicly accessible program.

Adaptation to floods in future climate: a practical approach

NASA Astrophysics Data System (ADS)

Doroszkiewicz, Joanna; Romanowicz, Renata; Radon, Radoslaw; Hisdal, Hege

2016-04-01

In this study some aspects of the application of the 1D hydraulic model are discussed with a focus on its suitability for flood adaptation under future climate conditions. The Biała Tarnowska catchment is used as a case study. A 1D hydraulic model is developed for the evaluation of inundation extent and risk maps in future climatic conditions. We analyse the following flood indices: (i) extent of inundation area; (ii) depth of water on flooded land; (iii) the flood wave duration; (iv) the volume of a flood wave over the threshold value. In this study we derive a model cross-section geometry following the results of primary research based on a 500-year flood inundation extent. We compare two methods of localisation of cross-sections from the point of view of their suitability to the derivation of the most precise inundation outlines. The aim is to specify embankment heights along the river channel that would protect the river valley in the most vulnerable locations under future climatic conditions. We present an experimental design for scenario analysis studies and uncertainty reduction options for future climate projections obtained from the EUROCORDEX project. Acknowledgements: This work was supported by the project CHIHE (Climate Change Impact on Hydrological Extremes), carried out in the Institute of Geophysics Polish Academy of Sciences, funded by Norway Grants (contract No. Pol-Nor/196243/80/2013). The hydro-meteorological observations were provided by the Institute of Meteorology and Water Management (IMGW), Poland.

USGS environmental characterization of flood sediments left in the New Orleans area after Hurricanes Katrina and Rita, 2005--Progress Report

USGS Publications Warehouse

Plumlee, Geoffrey S.; Meeker, Gregory P.; Lovelace, John K.; Rosenbauer, Robert J.; Lamothe, Paul J.; Furlong, Edward T.; Demas, Charles R.

2006-01-01

Introduction: The flooding in the greater New Orleans area that resulted from Hurricanes Katrina and Rita in September, 2005, left behind accumulations of sediments up to many centimeters thick on streets, lawns, parking lots, and other flat surfaces. These flood sediment deposits have been the focus of extensive study by the US Environmental Protection Agency (EPA) and Louisiana Department of Environmental Quality (LDEQ) due to concerns that the sediments may contain elevated levels of heavy metals, organic contaminants, and microbes. The U.S. Geological Survey (USGS) is characterizing a limited number of flood sediment samples that were collected on September 15-16 and October 6-7, 2005, from the greater New Orleans area by personnel from the USGS Louisiana Water Science Center in Baton Rouge. Small samples (< 3 pints each) of wet to dry flood sediment were collected from 11 localities around downtown New Orleans on September 15, 2005, and two large samples (40 pints each) of wet flood sediment were collected from the Chalmette area on September 16. Twelve additional samples (8-10 pints each) were collected from New Orleans, Slidell, Rigolets, and Violet on October 6 and 7. The USGS characterization studies of these flood sediments are designed to produce data and interpretations regarding how the sediments and any contained contaminants may respond to environmental processes. This information will be of use to cleanup managers and DoI/USGS scientists assessing environmental impacts of the hurricanes and subsequent cleanup activities.

Scales of Natural Flood Management

NASA Astrophysics Data System (ADS)

Nicholson, Alex; Quinn, Paul; Owen, Gareth; Hetherington, David; Piedra Lara, Miguel; O'Donnell, Greg

2016-04-01

The scientific field of Natural flood Management (NFM) is receiving much attention and is now widely seen as a valid solution to sustainably manage flood risk whilst offering significant multiple benefits. However, few examples exist looking at NFM on a large scale (>10km2). Well-implemented NFM has the effect of restoring more natural catchment hydrological and sedimentological processes, which in turn can have significant flood risk and WFD benefits for catchment waterbodies. These catchment scale improvements in-turn allow more 'natural' processes to be returned to rivers and streams, creating a more resilient system. Although certain NFM interventions may appear distant and disconnected from main stem waterbodies, they will undoubtedly be contributing to WFD at the catchment waterbody scale. This paper offers examples of NFM, and explains how they can be maximised through practical design across many scales (from feature up to the whole catchment). New tools to assist in the selection of measures and their location, and to appreciate firstly, the flooding benefit at the local catchment scale and then show a Flood Impact Model that can best reflect the impacts of local changes further downstream. The tools will be discussed in the context of our most recent experiences on NFM projects including river catchments in the north east of England and in Scotland. This work has encouraged a more integrated approach to flood management planning that can use both traditional and novel NFM strategies in an effective and convincing way.

a Novel Methodology for Developing Inundation Maps Under Climate Change Scenarios Using One-Dimensional Model

NASA Astrophysics Data System (ADS)

Vu, M. T.; Liong, S. Y.; Raghavan, V. S.; Liew, S. C.

2011-07-01

Climate change is expected to cause increases in extreme climatic events such as heavy rainstorms and rising tidal level. Heavy rainstorms are known to be serious causes of flooding problems in big cities. Thus, high density residential and commercial areas along the rivers are facing risks of being flooded. For that reason, inundated area determination is now being considered as one of the most important areas of research focus in flood forecasting. In such a context, this paper presents the development of a floodmap in determining flood-prone areas and its volumes. The areas and volumes of flood are computed by the inundated level using the existing digital elevation model (DEM) of a hypothetical catchment chosen for study. The study focuses on the application of Flood Early Warning System (Delft — FEWS, Deltares), which is designated to work with the SOBEK (Delft) to simulate the extent of stormwater on the ground surface. The results from FEWS consist of time-series of inundation maps in Image file format (PNG) and ASCII format, which are subsequently imported to ArcGIS for further calculations. In addition, FEWS results provide options to export the video clip of water spreading out over the catchment. Consequently, inundated area and volume will be determined by the water level on the ground. Final floodmap is displayed in colors created by ArcGIS. Various flood map results corresponding to climate change scenarios will be displayed in the main part of the paper.

Data collection and documentation of flooding downstream of a dam failure in Mississippi

USGS Publications Warehouse

Van Wilson, K.; ,

2005-01-01

On March 12, 2004, the Big Bay Lake dam failed, releasing water and affecting lives and property downstream in southern Mississippi. The dam is located near Purvis, Mississippi, on Bay Creek, which flows into Lower Little Creek about 1.9 miles downstream from the dam. Lower Little Creek flows into Pearl River about 16.9 miles downstream from the dam. Knowledge of the hydrology and hydraulics of floods caused by dam breaks is essential to the design of dams. A better understanding of the risks associated with possible dam failures may help limit the loss of life and property that often occurs downstream of a dam failure. The USGS recovered flood marks at the one crossing of Bay Creek and eight crossings of Lower Little Creek. Additional flood marks were also flagged at three other bridges crossing tributaries where backwater occurred. Flood marks were recovered throughout the stream reach of about 3/4 to 15 miles downstream of the dam. Flood marks that were flagged will be surveyed so that a flood profile can be documented downstream of the Big Bay Lake dam failure. Peak discharges are also to be estimated where possible. News reports stated that the peak discharge at the dam was about 67,000 cubic feet per second. Preliminary data suggest the peak discharge from the dam failure attenuated to about 13,000 cubic feet per second at Lower Little Creek at State Highway 43, about 15 miles downstream of the dam.

Flash Flood Risk Perception in an Italian Alpine Region. From Research into Adaptive Strategies.

NASA Astrophysics Data System (ADS)

Scolobig, A.; de Marchi, B.; Borga, M.

2009-04-01

Flash floods are characterised by short lead times and high levels of uncertainty. Adaptive strategies to face them need to take into account not only the physical characteristics of the hydro-geological phenomena, but also peoples' risk perceptions, attitudes and behaviours in case of an emergency. It is quite obvious that a precondition for an effective adaptation, e.g. in the case of a warning, is the awareness of being endangered. At the same time the perceptions of those at risk and their likely actions inform hazard warning strategies and recovery programmes following such events. Usually low risk awareness or "wrong perceptions" of the residents are considered among the causes of an inadequate preparedness or response to flash floods as well as a symptom of a scarce self-protection culture. In this paper we will focus on flood risk perception and on how research on this topic may contribute to design adaptive strategies and give inputs to flood policy decisions. We will report on a flood risk perception study of the population residing in four villages in an Italian Alpine Region (Trentino Alto-Adige), carried out between October 2005 and January 2006. A total of 400 standardised questionnaires were submitted to local residents by face to face interviews. The surveys were preceded by focus groups with officers from agencies in charge of flood risk management and semi-structured and in-depth interviews with policy, scientific and technical experts. Survey results indicated that people are not so worried about hydro-geological phenomena, and think that their community is more endangered than themselves. The knowledge of the territory and danger sources, the unpredictability of flash floods and the feeling of safety induced by structural devices are the main elements which make the difference in shaping residents' perceptions. The study also demonstrated a widespread lack of adoption of preparatory measures among residents, together with a general low evaluation of individual preparedness to face the events. At the same time there is a widespread trust in officials dealing with risk and emergency management, which confirms a general trend in delegating responsibility for safety to the agencies in charge. It is clear from the research findings that the problem is not only a lack of risk awareness and that flash flood risk perceptions are socially constructed in the sense that norms and values, as well as belief systems, influence and possibly define them. Several factors intervene in this process and most of them are highly context dependent. Therefore we underline the importance of understanding the local contexts and engaging with local perspectives on risk in the design of adaptive strategies. Taking these perspectives seriously into account is a prerequisite for the inclusion of those at risk in awareness raising processes, in developing and delivering strategies and in planning flood management, as required also by the European Floods Directive (EU 2007), which foresees "the active involvement of interested parties in the production, review and updating of the flood risk management plans ..." (Article 10). We also underline that a major effort in understanding how risk perception research can inform adaptive strategies is still needed to improve individual capability to positively face future flash flood emergencies.

Base (100-year) flood elevations for selected sites in Livingston County, Missouri

USGS Publications Warehouse

Southard, Rodney E.; Richards, Joseph M.

2002-01-01

The primary criteria for community participation in the National Flood Insurance Program is the adoption and enforcement of floodplain management requirements that minimize the potential for flood damages to existing and proposed development in flood-hazard areas. This report provides base flood elevations (BFE) for a 100-year recurrence-interval flood for use in the management and regulation of 18 flood-hazard areas designated by the Federal Emergency Management Agency as approximate Zone A areas in Livingston County, Missouri. The one-dimensional surface-water flow models HEC-RAS and Water-Surface PROfile (WSPRO) were used to compute base (100-year) flood elevations for 18 Zone A sites. The HEC-RAS model was used at BFE sites 1 to 6, 9, 10, and 15 to 18. The WSPRO model was used at BFE sites 7, 8, and 11 to 14. The 18 sites are all located in Livingston County, Missouri, at U.S., State, or County road crossings, and the base flood elevation was determined at the upstream side of each crossing. The base (100-year) flood elevations for BFE 1, 2, and 3 on Shoal Creek at Dawn and Shoal Creek Drainage Ditch near Dawn are 701.0, 701.0, and 696.5 feet, respectively. The base (100-year) flood elevations for BFE 4 and 5 on Indian Branch near Sampsel and a tributary to Indian Branch near Sampsel are 711.7 and 755.4 feet, respectively. Site BFE 6 is located on Honey Creek near Farmersville and the base (100-year) flood elevation for this site is 730.8 feet. One site (BFE 7) is located on No Creek near Farmersville. The base (100-year) flood elevation for this site is 731.3 feet. Site BFE 8 is located on Crooked Creek near Chillicothe and the base (100-year) elevation is 716.4 feet. One site (BFE 9) is located on a tributary to Coon Creek at Chillicothe. The base (100-year) flood elevation for this site is 734.9 feet. Two sites (BFE 10 and 11) are located on Blackwell Branch at Chillicothe. The base (100-year) flood elevation for BFE 10 is 738.9 feet and for BFE 11 is 701.7 feet. The base (100-year) flood elevation for BFE 12 on Medicine Creek near Chula is 721.7 feet. Sites BFE 13 and 15 are on Muddy Creek and for BFE 14 is on Little Muddy Creek near Chula. The base (100-year) flood elevations for BFE 13 and 15 are 733.0 and 717.9 feet, respectively and for BFE 14 is 734.6 feet. Downstream from BFE 12 is site BFE 16 on Medicine Creek near Wheeling. The base (100-year) flood elevation for site BFE 16 is 686.1 feet. One site (BFE 17) is located on Campbell Creek near Bedford. The base (100-year) flood elevation at this site is 691.8 feet. Site BFE 18 is located on Towstring Creek near Hale. The base (100-year) flood elevation for site BFE 18 is 667.4 feet.

BN-FLEMOps pluvial - A probabilistic multi-variable loss estimation model for pluvial floods

NASA Astrophysics Data System (ADS)

Roezer, V.; Kreibich, H.; Schroeter, K.; Doss-Gollin, J.; Lall, U.; Merz, B.

2017-12-01

Pluvial flood events, such as in Copenhagen (Denmark) in 2011, Beijing (China) in 2012 or Houston (USA) in 2016, have caused severe losses to urban dwellings in recent years. These floods are caused by storm events with high rainfall rates well above the design levels of urban drainage systems, which lead to inundation of streets and buildings. A projected increase in frequency and intensity of heavy rainfall events in many areas and an ongoing urbanization may increase pluvial flood losses in the future. For an efficient risk assessment and adaptation to pluvial floods, a quantification of the flood risk is needed. Few loss models have been developed particularly for pluvial floods. These models usually use simple waterlevel- or rainfall-loss functions and come with very high uncertainties. To account for these uncertainties and improve the loss estimation, we present a probabilistic multi-variable loss estimation model for pluvial floods based on empirical data. The model was developed in a two-step process using a machine learning approach and a comprehensive database comprising 783 records of direct building and content damage of private households. The data was gathered through surveys after four different pluvial flood events in Germany between 2005 and 2014. In a first step, linear and non-linear machine learning algorithms, such as tree-based and penalized regression models were used to identify the most important loss influencing factors among a set of 55 candidate variables. These variables comprise hydrological and hydraulic aspects, early warning, precaution, building characteristics and the socio-economic status of the household. In a second step, the most important loss influencing variables were used to derive a probabilistic multi-variable pluvial flood loss estimation model based on Bayesian Networks. Two different networks were tested: a score-based network learned from the data and a network based on expert knowledge. Loss predictions are made through Bayesian inference using Markov chain Monte Carlo (MCMC) sampling. With the ability to cope with incomplete information and use expert knowledge, as well as inherently providing quantitative uncertainty information, it is shown that loss models based on BNs are superior to deterministic approaches for pluvial flood risk assessment.

The role of Natural Flood Management in managing floods in large scale basins during extreme events

NASA Astrophysics Data System (ADS)

Quinn, Paul; Owen, Gareth; ODonnell, Greg; Nicholson, Alex; Hetherington, David

2016-04-01

There is a strong evidence database showing the negative impacts of land use intensification and soil degradation in NW European river basins on hydrological response and to flood impact downstream. However, the ability to target zones of high runoff production and the extent to which we can manage flood risk using nature-based flood management solution are less known. A move to planting more trees and having less intense farmed landscapes is part of natural flood management (NFM) solutions and these methods suggest that flood risk can be managed in alternative and more holistic ways. So what local NFM management methods should be used, where in large scale basin should they be deployed and how does flow is propagate to any point downstream? Generally, how much intervention is needed and will it compromise food production systems? If we are observing record levels of rainfall and flow, for example during Storm Desmond in Dec 2015 in the North West of England, what other flood management options are really needed to complement our traditional defences in large basins for the future? In this paper we will show examples of NFM interventions in the UK that have impacted at local scale sites. We will demonstrate the impact of interventions at local, sub-catchment (meso-scale) and finally at the large scale. These tools include observations, process based models and more generalised Flood Impact Models. Issues of synchronisation and the design level of protection will be debated. By reworking observed rainfall and discharge (runoff) for observed extreme events in the River Eden and River Tyne, during Storm Desmond, we will show how much flood protection is needed in large scale basins. The research will thus pose a number of key questions as to how floods may have to be managed in large scale basins in the future. We will seek to support a method of catchment systems engineering that holds water back across the whole landscape as a major opportunity to management water in large scale basins in the future. The broader benefits of engineering landscapes to hold water for pollution control, sediment loss and drought minimisation will also be shown.

Geographic Information and Remotely Sensed Data For The Assessment and Monitoring of The Flood Hazard In Romania

NASA Astrophysics Data System (ADS)

Predescu, C.; Stancalie, G.; Savin, E.

Floodings represent an important risk in many areas around the globe and especially in Romania. In the latest years floodings occurred quite frequently in Romania, some of which isolated, others were affecting wide areas of the countrySs territory. The paper assumes a modern approach for the flooding risk indices, associated to the physic- geographical, morpho-hydrographical and vulnerability characteristics of a region, in view to establish a methodology which should further allow to determine the flooding risk, using representatives indices at a scale compatible with a synthetic representa- tion of the territory. There are stressed the facilities supplied by the Geographic Infor- mation System (GIS) and the remotely sensed data to manage flooding during their characteristic phases: before, during and after flooding. Accent is laid on the pre and post-crisis phases. An important research topic was the study of the parameters that can be extracted from satellite images in view of organising a hierarchy of the geo- graphical space versus the flooding risk. Information obtained from satellite images proved to be useful for the determination of certain parameters necessary to monitor flooding: hydrographic network, water accumulation, size of floodable surface, land impermeability degree, water absorption capacity over the basin surface, resilience to in-soil water infiltration. The study encompassed both the risk degree levels related with various parameters, which condition and determine floodings, and the one, which takes into consideration the human presence in the sensitive areas. It was planned to design and build a database, which will help to elaborate the flooding hydrological risk indices. The application was developed for the Arges hydrographic basin in Romania, a critical area, keeping in mind that it withholds many localities, including the capital and also important economic centres. The database allows obtaining synthetic repre- sentations of the hydrologic risk for the Arges basin, through separate or combined use of the risk parameters as well as for interfacing with the hydrological models in view to improve them as regards recovering results and the possibility to achieve scenarios.