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1

Evaluation of soil erosion as a basis of sediment yield in mountainous catchments: a preliminary study in the River Douro Basin (Northern Portugal)  

NASA Astrophysics Data System (ADS)

The River Corgo drains a meso-scale mountainous rural catchment with an area of 295 km2, underlain by crystalline rocks, in a temperate climate, which integrates the transboundary River Douro Basin, in the northeast of Portugal. A geochemical survey on oxic fluvial sediments of the river network shows considerable contents of metals associated to the finer particles (< 63um). The results on the study of the sediment properties indicate that these are essentially detrital in origin, derived from soils and weathering products. Moreover, taking into account the hydrological pattern of the catchment, the seasonal and spatial variability of metal contents associated to the sediments suggests that the control of metal in the sediments by their mineralogical, geochemical and physical properties is governed primarily at the level of the basin soils system, especially in the Wet Period, when the sediments are frequently remobilised (Reis, 2010). Although the soil particles are a common pathway of transport and entrance of metals in the fluvial network by runoff derived erosion, this mechanism is naturally more marked in mountainous catchments. Modelling sediment and adsorbed contaminant transport within catchments can help to identify possible contaminant sources, as well as to estimate the delivered quantities of eroded material and associated contaminants. In catchments with the described morphological features, monitoring the transport of sediments poses some issues concerning: (a) the low mass yield of suspended sediment from river water, under low-flow conditions; (b) the maintenance of the sediment sampler's devices in the streams, in periods of high-flow or storm events. This study describes the preliminary results of a GIS-based mass balance model of overland sediment transport to the River. The erosion, the first step of sediment transport, was estimated by an empirical model - The Universal Soil Loss Equation (USLE). The objective was to construct a GIS based potential soil loss spatial index model and posteriorly estimate the sediment yield for different locations within the catchment. The R factor was obtained from the literature; K factor was derived from the Soil Map of Trás-os-Montes; LS factor was calculated from the elevation digital model using the Simms et al. (2003) equation; C and P factors were derived from the Corin Land Cover Map produced for Portugal in 2006. The preliminary results indicate that the model is in accordance with the knowledge of the study area, and can be used as an initial indicator of areas of potential sediment source. So, the results show that potential loss is typically higher along the areas where the tributaries are deeply incised and bordered by steeper slopes, with locally extreme values. REFERENCES REIS, A. R. (2010) - Occurrence and mobilisation of non-organic micro-pollutants in mountainous riverine systems. PhD Thesis (unpublished), University of Trás-os-Montes e Alto Douro, Vila Real, 453 pp. SIMMS, A., WOODROFFE, C. & JONES, B. (2003) - Application of RUSLE for erosion management in a coastal catchment, southern NSW. MODSIM 2003: Intern. Congress on Modelling and Simulation, vol.2, Integrative Modelling of Biophysical, Social and Economic Systems for Resource Management Solutions, Australia, pp. 678-683.

Reis, Anabela; Martinho Lourenço, José M.; Parker, Andrew; Alencoão, Ana

2013-04-01

2

The Thames Catchment: A River Basin at the Tipping Point  

Microsoft Academic Search

The paper recapitulates the theory of catchment water deficits and the use of density analysis previously published in this journal. Thereafter theory and method are applied to the Thames River Basin in England where it is shown that the catchment is marginally in deficit but that future developments in population growth, output growth and climate change require the application of

Stephen Merrett

2005-01-01

3

Catchment salt balances in the Queensland Murray-Darling Basin, Australia  

NASA Astrophysics Data System (ADS)

Catchment salt balances were calculated for the Queensland Murray-Darling Basin.The Basin is accumulating salt at the regional scale.Small eastern catchments are exporting salt.Variation in method of calculation affects the result and interpretation.

Biggs, Andrew J. W.; Silburn, D. Mark; Power, R. Edward

2013-09-01

4

Analyzing catchment behavior through catchment modeling in the Gilgel Abay, Upper Blue Nile River Basin, Ethiopia  

NASA Astrophysics Data System (ADS)

Understanding catchment hydrological processes is essential for water resources management, in particular in data scarce regions. The Gilgel Abay catchment (a major tributary into Lake Tana, source of the Blue Nile) is undergoing intensive plans for water management, which is part of larger development plans in the Blue Nile basin in Ethiopia. To obtain a better understanding of the water balance dynamics and runoff generation mechanisms and to evaluate model transferability, catchment modeling has been conducted using the conceptual hydrological model HBV. Accordingly, the catchment of the Gilgel Abay has been divided into two gauged sub-catchments (Upper Gilgel Abay and Koga) and the un-gauged part of the catchment. All available data sets were tested for stationarity, consistency and homogeneity and the data limitations (quality and quantity) are discussed. Manual calibration of the daily models for three different catchment representations, i.e. (i) lumped, (ii) lumped with multiple vegetation zones, and (iii) semi-distributed with multiple vegetation and elevation zones, showed good to satisfactory model performances with Nash-Sutcliffe efficiencies Reff > 0.75 and > 0.6 for the Upper Gilgel Abay and Koga sub-catchments, respectively. Better model results could not be obtained with manual calibration, very likely due to the limited data quality and model insufficiencies. Increasing the computation time step to 15 and 30 days improved the model performance in both sub-catchments to Reff > 0.8. Model parameter transferability tests have been conducted by interchanging parameters sets between the two gauged sub-catchments. Results showed poor performances for the daily models (0.30 < Reff < 0.67), but better performances for the 15 and 30 days models, Reff > 0.80. The transferability tests together with a sensitivity analysis using Monte Carlo simulations (more than 1 million model runs per catchment representation) explained the different hydrologic responses of the two sub-catchments, which seems to be mainly caused by the presence of dambos in Koga sub-catchment. It is concluded that daily model transferability is not feasible, while it can produce acceptable results for the 15 and 30 days models. This is very useful for water resources planning and management, but not sufficient to capture detailed hydrological processes in an ungauged area.

Uhlenbrook, S.; Mohamed, Y.; Gragne, A. S.

2010-10-01

5

Exploratory Shaft Facility Preliminary Designs - Permian Basin.  

National Technical Information Service (NTIS)

The purpose of the Preliminary Design Report, Permian Basin, is to provide a description of the preliminary design for an Exploratory Shaft Facility in the Permian Basin, Texas. This issue of the report describes the preliminary design for constructing th...

1983-01-01

6

Isotope hydrology of catchment basins: lithogenic and cosmogenic isotopic systems  

SciTech Connect

A variety of physical processes affect solute concentrations within catchment waters. The isotopic compositions of the solutes can indicate which processes have determined the observed concentrations. These processes together constitute the physical history of the water. Many solutes in natural waters are derived from the interaction between the water and the rock and/or soil within the system - these are termed `lithogenic` solutes. The isotopic compositions of these solutes provide information regarding rock-water interactions. Many other solutes have their isotopic compositions determined both within and outside of the catchment - i.e., in addition to being derived from catchment rock and soil, they are solutes that are also transported into the catchment. Important members of this group include solutes that have isotopic compositions produced by atomic particle interactions with other nuclides. The source of the atomic particles can be cosmic radiation (producing `cosmogenic` nuclides in the atmosphere and land surface), anthropogenic nuclear reactions (producing `thermonuclear` nuclides), or radioactive and fission decay of naturally-occurring elements, principally {sup 238}U (producing `in-situ` lithogenic nuclides in the deep subsurface). Current language usage often combines all of the atomic particle-produced nuclides under the heading `cosmogenic nuclides`, and for simplicity we will often follow that usage here, although always indicating which variety is being discussed. This paper addresses the processes that affect the lithogenic and cosmogenic solute concentrations in catchment waters, and how the isotopic compositions of the solutes can be used in integrative ways to identify these processes, thereby revealing the physical history of the water within a catchment system. The concept of a `system` is important in catchment hydrology. A catchment is the smallest landscape unit that can both participate in all of the aspects of the hydrologic cycle and also be treated as a mostly closed system for mass balance considerations. It is the near closure of the system that permits well- constrained chemical mass balance calculations to be made. These calculations generally focus of lithogenic solutes, and therefore in our discussions of lithogenic nuclides in the paper, the concept of chemical mass balance in a nearly dosed system will play an important role. Examination of the isotopic compositions of solutes provides a better understanding of the variety of processes controlling mass balance. It is with this approach that we examined the variety of processes occurring within the catchment system, such as weathering and soil production, generation of stormflow and streamflow (hydrograph separation), movement of soil pore water, groundwater flow, and the overall processes involved with basinal water balance. In this paper, the term `nuclide` will be used when referring to a nuclear species that contains a particular number of protons and neutrons. The term is not specific to any element. The term `isotope` will be used to distinguish nuclear species of a given element (atoms with the same number of protons). That is to say, there are many nuclides in nature - for example, {sup 36}Cl, {sup 87}Sr, {sup 238}U; the element has four naturally-occurring isotopes - {sup 87}Sr, and {sup 88}Sr. This paper will first discuss the general principles that underlie the study of lithogenic and cosmogenic nuclides in hydrology, and provide references to some of the more important studies applying these principles and nuclides. We then turn in the second section to a discussion of their specific applications in catchment- scale systems. The final section of this paper discusses new directions in the application of lithogenic and cosmogenic nuclides to catchment hydrology, with some thoughts concerning possible applications that still remain unexplored.

Nimz, G. J., LLNL

1998-06-01

7

A Basin-Averaged Water Balance Approach to Estimate Catchment-Scale Groundwater Flow in a Semi-arid Mountainous Catchment  

NASA Astrophysics Data System (ADS)

Quantification of the contribution of groundwater flow from highland areas of mountainous watersheds to semi-arid and arid valley bottom unconsolidated aquifers is increasingly needed for the assessment of water resources in many populated areas. In mountainous environments, however, data for Darcy equation parameters are limited, leading to uncertainty in estimates of groundwater flow of up to two or more orders of magnitude. An alternative method for estimating regional groundwater flow from highland to valley bottom areas was developed for the semi-arid Okanagan Basin, British Columbia, Canada. The method involved a basin-averaged water balance approach, using mean annual surface water run-off (RO) data for 9 gauged tributaries with spatially distributed estimates of mean annual precipitation (P) and actual evapotranspiration (AET), to develop basin-averaged relationships for prediction of recharge-driven groundwater flow through the bedrock highland areas. Groundwater flow from highland bedrock areas to unconsolidated valley bottom aquifers was subsequently accounted for through a calibration exercise using a spreadsheet tool developed for the project. Average annual AET was the most difficult parameter to quantify at the tributary catchment scale. Spatially distributed AET estimates were developed using temperature and precipitation data, with consideration of expected AET ranges established based on available data for the region. Results for the bedrock areas in the Okanagan Basin indicated basin-averaged partitioning of mean annual precipitation as 68% AET, 19% to surface water run-off (in streams), and 13% to net recharge (groundwater flow). The influence of AET and surface water run-off parameter uncertainty on regional bedrock groundwater flow calculations was a factor of 2 (AET range of 60-70% catchment precipitation) and 1.2 (RO range of 14 to 26%), respectively. This approach allows for preliminary estimates of water budget constrained recharge- driven groundwater flow at the catchment or basin scale.

Neilson-Welch, L. A.; Allard, R.; Geller, D.; Allen, D. M.

2008-12-01

8

Preliminary investigation of catchment hydrology in response to agricultural water use innovations: A case study of the Potshini catchment South Africa  

NASA Astrophysics Data System (ADS)

Water use system innovations encompass various techniques for storing and conserving water resources in different mediums for domestic and livestock use including agricultural production. Although, several authors have indicated that rainwater harvesting techniques, especially for upgrading smallholder farming systems, are not new but have been practiced since ancient civilizations, the impacts of such water use innovations on eco-hydrological systems are rarely assessed, especially from a cascading spatial and temporal perspective. The need to quantify the supposedly potential and related hydrological impacts of water use innovations on a catchment and river basin at large, led to the on-going research study aimed at investigating the biophysical consequences at different spatial and temporal scales in the Thukela river basin, of increased productivity in smallholder rainfed agriculture enabled through adoption at larger spatial scale of integrated land use management and water use system innovations. In this paper we discuss and outline the approach used in setting up the research study in one of the catchments in the Thukela river basin, the Potshini catchment, in the KwaZulu-Natal Province of South Africa in an effort to seek answers to the question: “What is the impact of adapting water use innovations in a predominantly agricultural area on catchment ecology and hydrology?” The approach incorporates a catchment monitoring network, hydrological modelling and application of a remote sensing technique, the Surface Energy Balance Algorithm for Land (SEBAL), for spatially estimating the total evaporation in the region covering the Potshini catchment and beyond. Preliminary results indicate that water use innovations in the Potshini catchment have influenced the partitioning of rainfall, by significantly reducing surface runoff over agricultural lands under conservation tillage practices, with a reduction of above 100%, while encouraging infiltration and deeper percolation into the soil. It is envisaged that, on accomplishment, the study will contribute to formulation of sustainable adaptation of water use innovations and up-scaling strategies to enhance food production and hydro-ecological balance in semi-arid savannahs of Africa, at which stage hydrological modelling will form an important part of the study.

Kongo, V. M.; Jewitt, G. P. W.

9

Probabilistic forecasting at ungauged basins: using neighbour catchments for model calibration and updating  

Microsoft Academic Search

This study evaluates the quality of probabilistic streamflow forecasts at ungauged basins when using neighbour catchments for model calibration and updating. Many studies have been carried out to estimate the local parameters at ungauged basins for flow simulation and flow quantile estimation. However, approaches devoted to the question of streamflow forecasting at ungauged basins are rarer. In fact, in flow

Annie Randrianasolo; Maria-Helena Ramos; Vazken Andréassian

2010-01-01

10

Coupling catchment hydrology and landscape evolution: Interactive effects on hydrograph and basin shape  

NASA Astrophysics Data System (ADS)

The catchment hydrologic response to rainfall and the evolution of the river basin network and landscape morphology are closely linked phenomena, albeit active over different temporal scales. While the relation between hydrograph shape and catchment form has long been hypothesized, little is yet understood about the evolution of the basin hydrologic response with catchment age or geomorphic condition. Similarly, the long-term morphologic changes and feedbacks associated with a spatially-variable, evolving runoff response are still unknown. Understanding the complex interaction between basin hydrology and geomorphology was an important pursuit during Michael J. Kirkby's scientific career. In this study, we describe the interactive effects and feedbacks between the basin hydrograph (hydrologic response) and shape (geomorphic response) utilizing two state-of-the-art models: the Channel-Hillslope Integrated Landscape Development (CHILD) and the TIN-based Real-time Integrated Basin Simulator (tRIBS). We first illustrate the changes occurring in the basin hydrograph, variable source area and channel network as the catchment evolves. We then describe how the spatially-explicit hydrologic response from various mechanisms and its associated moisture field directly impacts the erosion and subsequently the basin shape. Quantitative comparisons are then made between a set of interactive and non-interactive simulations for idealized conditions. Our ultimate goal is to highlight the need for coupling distributed simulations of catchment hydrology and geomorphology for investigating the interaction between basin and hydrograph shape.

Vivoni, E. R.; Istanbulluoglu, E.; Bras, R. L.

2003-12-01

11

Climate change impacts on hydrological extremes (floods, low flows) along catchments in the Scheldt river basin  

Microsoft Academic Search

The potential climate change impacts on hydrological extremes (floods and low flows) have been investigated for rivers in highly urbanized catchments in the Scheldt river basin in Belgium. Results of 31 simulations with 11 Regional Climate Models (RCMs) from the EU PRUDENCE project were statistically analyzed for both the control period 1961-1990 and the scenario period 2071-2100. The more recent

Victor Ntegeka; Patrick Willems; Pierre Baguis; Emmanuel Roulin; Thomas Vansteenkiste; Katijn Holvoet

2010-01-01

12

Analysis of Annual Dissolved Solids Loading from Selected Natural and Irrigated Catchments in the Upper Colorado River Basin, 1974-2003.  

National Technical Information Service (NTIS)

Dissolved-solids loading from 17 natural catchments and 14 irrigated catchments in the Upper Colorado River Basin was examined for the period from 1974 through 2003. In general, dissolved-solids loading increased and decreased concurrently in natural and ...

2012-01-01

13

Hydrochemical Linkage of Groundwater and Surface Water in a Small Catchment Basin, SE Massachusetts  

Microsoft Academic Search

Wildcat and Third Herring Brooks drain a small catchment basin approximately 8.2 sq.mi in size located in a moderately populated region in southeastern Massachusetts. Both streams flow through a semi-urban partially developed forested land with no municipal sewer system and with varied density of roads serviced in the winter season with deicing chemicals. Two towns (Hanover and Norwell) share the

R. Hon; P. Dillon; N. Merritt

2004-01-01

14

A combined deterministic and self-adaptive stochastic algorithm for streamflow forecasting with application to catchments of the Upper Murray Basin, Australia  

Microsoft Academic Search

This paper describes the results of runoff modelling for nine catchments of the Upper Murray Basin (Basin 401) of the Murray-Darling Drainage Division (MDDD), Australia. The work aimed firstly to provide adequate models for long-term streamflow prediction in nine catchments of this Basin feeding the Hume and Dartmouth reservoirs. The development and testing of flow forecasting algorithms for operational management

S. Yu. Schreider; A. J. Jakeman; B. G. Dyer; R. I. Francis

1997-01-01

15

The 20th century whole-basin trophic history of an inter-drumlin lake in an agricultural catchment.  

PubMed

Eight 1-m sediment cores were extracted from across the basin of Friary Lough, a 5.4-ha eutrophic lake in a wholly grassland agricultural catchment in Co. Tyrone, Northern Ireland. Sedimentary TP, diatom inferred TP, Ca, Na, Fe, Mn, loss-on-ignition (LOI), dry weight and density were determined in the core profiles. Core dating and correlation gave a 210Pb, 137Cs and 241Am chronology from 1906 to 1995 and enabled a whole-basin estimate of chemical and sediment accumulation rate over the 20th Century. The major changes for all parameters occurred after c. 1946. Sediment accumulation rate was most influenced by organic matter accumulations, probably of planktonic origin, and increasing after c. 1946. Inorganic sediment accumulation rate was found to be largely unchanging through the century at 10 t km(-2) yr(-1) when expressed as catchment exports. All chemical accumulation rate changes occurred after c. 1946. Total phosphorus accumulation rate, however, was found to be the only chemical to be increasing throughout the epilimnion and hypolimnion areas of the sedimentary basin at an average of 22.5 mg m(-2) yr(-1) between 1946 and 1995. The other chemical parameters showed increasing accumulation rates after c. 1946 in the epilimnion part of the basin only. Interpreted in terms of whole-basin sedimentation and catchment export processes over time, it is suggested that diffuse TP inputs are independent of sediment inputs. This corresponds to hydrochemical models that suggest soluble P as the primary fraction that is lost from grassland catchments. The increase in sedimentary TP accumulation rate, and DI-TP concentration, are also explained with regard to current models that suggest increases in runoff P concentrations from elevated soil P concentrations. Increases in eplimnion chemical and sediment accumulation rate after c. 1946 may be due to local erosion that has limited impact on lake basin sedimentation. PMID:12389788

Jordan, Philip; Rippey, Brian; Anderson, N John

2002-10-01

16

Rainfall–interception–evaporation–runoff relationships in a semi-arid catchment, northern Limpopo basin, Zimbabwe  

Microsoft Academic Search

Characterizing the response of a catchment to rainfall, in terms of the production of runoff vs the interception, transpiration and evaporation of water, is the first important step in understanding water resource availability in a catchment. This is particularly important in small semi-arid catchments, where a few intense rainfall events may generate much of the season's runoff. The ephemeral Zhulube

David Love; Stefan Uhlenbrook; Gerald Corzo-Perez; Steve Twomlow; Pieter van der Zaag

2010-01-01

17

A Proposed Framework for the Identification of Habitat Utilisation Patterns of Macrophytes in River Po Catchment Basin Lakes (Italy)  

Microsoft Academic Search

The main aim of this study, which is based on cover-abundance values of 20 species of floating-leaved and submersed macrophytes collected in 18 lakes located within the River Po catchment basin (Italy), is to investigate the relationships between lake-scale environmental features (including morphology, hydrology, trophic state and water quality variables) and the changes in species composition and species richness in

Alessandro Ludovisi; Piera Pandolfi; M. Illuminata Taticchi

2004-01-01

18

Major ion chemistry, weathering processes and water quality assessment in upper catchment of Damodar River basin, India  

Microsoft Academic Search

The chemical characteristics of surface, groundwater and mine water of the upper catchment of the Damodar River basin were\\u000a studied to evaluate the major ion chemistry, geochemical processes controlling water composition and suitability of water\\u000a for domestic, industrial and irrigation uses. Water samples from ponds, lakes, rivers, reservoirs and groundwater were collected\\u000a and analysed for pH, EC, TDS, F, Cl,

Abhay Kumar Singh; G. C. Mondal; Suresh Kumar; T. B. Singh; B. K. Tewary; A. Sinha

2008-01-01

19

Mn-oxides and sequestration of heavy metals in a suburban catchment basin of the Chesapeake Bay watershed  

Microsoft Academic Search

The Chesapeake Bay is greatly impacted by numerous pollutants including heavy metals and understanding the controls on the\\u000a distribution of heavy metals in the watershed is critical to mitigation and remediation efforts in controlling this type of\\u000a pollution. Clasts from a stormwater catchment basin draining a subdivision near George Mason University, Fairfax VA (38°50.090°N\\u000a 78°19.204°W) were investigated using X-ray diffraction

James P. Adams; Robert Kirst; Lance E. Kearns; Mark P. S. Krekeler

2009-01-01

20

Geo-referenced modelling of metal concentrations in river basins at the catchment scale  

NASA Astrophysics Data System (ADS)

1. Introduction The European Water Framework Directive demands the good ecological and chemical state of surface waters [1]. This implies the reduction of unwanted metal concentrations in surface waters. To define reasonable environmental target values and to develop promising mitigation strategies a detailed exposure assessment is required. This includes the identification of emission sources and the evaluation of their effect on local and regional surface water concentrations. Point source emissions via municipal or industrial wastewater that collect metal loads from a wide variety of applications and products are important anthropogenic pathways into receiving waters. Natural background and historical influences from ore-mining activities may be another important factor. Non-point emissions occur via surface runoff and erosion from drained land area. Besides deposition metals can be deposited by fertilizer application or the use of metal products such as wires or metal fences. Surface water concentrations vary according to the emission strength of sources located nearby and upstream of the considered location. A direct link between specific emission sources and pathways on the one hand and observed concentrations can hardly be established by monitoring alone. Geo-referenced models such as GREAT-ER (Geo-referenced Regional Exposure Assessment Tool for European Rivers) deliver spatially resolved concentrations in a whole river basin and allow for evaluating the causal relationship between specific emissions and resulting concentrations. This study summarizes the results of investigations for the metals zinc and copper in three German catchments. 2. The model GREAT-ER The geo-referenced model GREAT-ER has originally been developed to simulate and assess chemical burden of European river systems from multiple emission sources [2]. Emission loads from private households and rainwater runoff are individually estimated based on average consumption figures, runoff rates and the site-specific population and surface area (roof, gutter, street) connected to the local sewer system. For emissions from industry and mine drainage quantitative data on average annual loads are collected. WWTP effluent loads additionally consider average removal during wastewater treatment. Runoff from non-point sources such as agricultural areas and unsealed soils is estimated from average wash-off rates per area multiplied with the total area drained into a specified river reach of the river system. Groundwater infiltration is considered in quantities equal to the base flow in the respective river stretch. The model simulates the steady-state concentration distribution in the whole river basin considering transport and removal processes in the river system. The only major removal process for metals in surface water is sedimentation. Simulations have been carried out exemplary for zinc and copper in the German river basins Main (27,292 km2), Ruhr (4,485 km2) and Sieg (2,832 km2). 3. Results and discussion Model estimations of effluent loads for selected WWTPs agreed well with available surveillance data so that the emission module outcome can be assumed as appropriate starting point for surface water modeling. A detailed comparison of simulated surface water concentrations with monitoring data was performed for zinc in the Ruhr river basin. Good agreement between monitoring data and model simulations was achieved at 20 monitoring sites in the Ruhr River and its major tributaries. GREAT-ER was able to simulate zinc concentrations in surface waters based on estimation of loads from several emission sources and via different emission pathways. A wide applicability of the model was corroborated by successful simulations of zinc concentrations in the Main river basin and simulations for copper in both catchments. The functionality of the model allows for running scenarios with different emission assumptions that can be easily compared. Such case studies can be used to demonstrate the effect of specific mitigation strategies such as improved treatment of ra

Hüffmeyer, N.; Berlekamp, J.; Klasmeier, J.

2009-04-01

21

Unusual seasonal patterns and inferred processes of nitrogen retention in forested headwater catchments of the Upper Susquehanna basin  

NASA Astrophysics Data System (ADS)

The Susquehanna River provides two-thirds of the annual nitrogen (N) load to the Chesapeake Bay, and atmospheric deposition is a major contributor to the basin's N inputs. Yet, there are few measurements of the retention of atmospheric N in the Upper Susquehanna's forested headwaters. We characterized the amount, form (nitrate, ammonium, and dissolved organic nitrogen), isotopic composition (del18O- and del15N-nitrate), and seasonality of stream N over two years from 8-15 small forested headwater catchments of the Susquehanna Basin. We expected high rates of N retention and seasonal nitrate patterns typical of other seasonally snow-covered catchments: dormant season peaks and growing season minima. Annual nitrate exports were approximately 0.1-0.7 kg N ha-1 y-1, and correlated positively with the percent of catchment free from historical agriculture. DON export averaged 0.6 +/- 0.1 kg N ha-1 y-1. All catchments had high rates of N retention but with atypical seasonal nitrate patterns, consisting of summer peaks, fall crashes, and modest rebounds during the dormant season. The fall nitrate crash coincided with carbon inputs at leaffall, indicating in-stream heterotrophic uptake. Stream del18O-nitrate values indicated microbial nitrification as the dominant source of stream nitrate, with modest contributions directly from precipitation in early stages of snowmelt. Three hypothesized sources of summer nitrate peaks include: delayed release of nitrate flushed to groundwater at snowmelt, weathering of geologic N, and increased net nitrate production. Measurements of shale del15N as well as soil, well-, and springwater nitrate within one catchment point toward a summer increase in net nitrification in surface soils. Rather than plant demand, processes governing the production, retention, and hydrologic transport of nitrate in surface mineral soils may drive the unusual nitrate seasonality in this and other systems, and provide insights on N retention in general.

Goodale, C. L.; Thomas, S. A.; Fredriksen, G.; Elliott, E. M.; Flinn, K. M.; Butler, T. J.

2008-12-01

22

Comparison of Late Quaternary Climate Development Between the Niger Catchment Area and the Amazon Basin  

NASA Astrophysics Data System (ADS)

The inorganic terrigenous fraction of marine sediments offers a great number of different and well established proxy parameters to investigate the development of continental climate. In this study we present high resolution records of terrigenous source elements from the Niger River and the Amazon River fans. Sediment cores are well dated by radiocarbon measurements. Elemental records from both regions reveal strong evidence for rapid continental climate change over the last 18.000 years, especially during last deglaciation. While major changes obviously occure nearly simultaneously, the timing of shorter events is clearly offset between the two regions. In addition, significant differences can be recorded for the development of the sedimentary terrigenous composition during the Late Holocene. While element ratios indicates increasing arid conditions in catchment area of the Niger since the end of the last African Humid Period at about 5.5 kyr ago, in consistency with other studies increasing humid conditions prevail in the Amazon Basin during the Holocene. This opposing climate development could be caused by the discussed E-W SST contrasts due to variations in the thermohaline circulation within the tropical Atlantic. However, in order to support our findings in marine sediments and because we know that the terrigenous fraction in marine sediments contains to a certain degree a filtered climatic information due to Land-ocean transport and depositinal processes, we try to verify information from the marine records by additional information from the adjacent region like on sea and lake level fluctuations.

Zabel, M.; Ettwein, V.; Maslin, M.; Schneider, R. R.

2003-04-01

23

Isotopic time-series partitioning of streamflow components in wetland-dominated catchments, lower Liard River basin, Northwest Territories, Canada  

NASA Astrophysics Data System (ADS)

The distribution of stable water isotopes provides valuable insight into runoff generation processes in subarctic wetland regions of the Mackenzie River basin, a major freshwater contributor to the Arctic Ocean and the focus of intensive hydrological research as part of Canada's contribution to the Global Energy and Water Cycle Experiment (GEWEX). This article describes a streamflow hydrograph separation analysis carried out over three complete annual cycles (1997-1999) for five subarctic catchments ranging in size from 202 to 2050 km2 situated near the confluence of the Liard and Mackenzie rivers. This heterogeneous landscape, characterized by extensive wetlands (fen and bog), shallow lakes and widespread discontinuous permafrost, is representative of vast flow-contributing areas of the upper Mackenzie Valley, and is suspected to be highly sensitive to climate variability and change. We document seasonal patterns and interannual variability in the isotopic composition of local streamflow, attributable to mixing of three distinctly labelled flow sources, namely groundwater, surface water plus rain, and direct snowmelt, and apply these isotopic signals to partition sources and their temporal variability. Although groundwater input is the dominant and most persistent streamflow source in all five catchments throughout the year, direct snowmelt runoff via surface and shallow subsurface pathways (during spring freshet) and surface waters from lakes and wetlands situated in low-lying areas of the basins (during summer and fall) are also significant seasonal contributors. Catchment-specific differences are also apparent, particularly in the generation of snowmelt runoff, which is more attenuated in fen-dominated than in bog-dominated catchments. The data set additionally reveals notable interannual variability in snow isotope signatures and snow water equivalent, apparently enhanced by the 1998 El Niño event. Copyright

St Amour, Natalie A.; Gibson, John J.; Edwards, Thomas W. D.; Prowse, Terry D.; Pietroniro, Alain

2005-11-01

24

Hydrochemical Linkage of Groundwater and Surface Water in a Small Catchment Basin, SE Massachusetts  

NASA Astrophysics Data System (ADS)

Wildcat and Third Herring Brooks drain a small catchment basin approximately 8.2 sq.mi in size located in a moderately populated region in southeastern Massachusetts. Both streams flow through a semi-urban partially developed forested land with no municipal sewer system and with varied density of roads serviced in the winter season with deicing chemicals. Two towns (Hanover and Norwell) share the underlying aquifer by pumping on average 1.5 Mgal per day, a rate which significantly influences infiltration / discharge patterns and seasonal water budget. The aquifer is situated in a buried valley filled with glacial outwash deposits in some parts and peat deposits underneath wetlands in others. Correspondingly, water quality within the aquifer reflects these two distinct geological surficial enviroregions. Anerobic reducing water enriched in Fe and Mn is associated with the peat layers and oxygenated, low Fe and Mn water exists in the outwash subregion. Normal flow of ground water parallels the boundary between these ecoregions with a minimal mixing between these two hydrochemical ground water domains. However, water withdrawal during pumping tests showed that both ground water types can mix with a formation of precipitates of Fe and Mn hydroxides. Water quality is also influenced by dissolution of deicing chemicals. Water drawn from wells located closer to the streams have higher sodium and chloride concentrations than water in the wells located further away. Planning and management of water supply resources has to take into account variations of hydrochemical characteristics within the aquifer as well as the extent of interactions between the streams and the ground water system.

Hon, R.; Dillon, P.; Merritt, N.

2004-05-01

25

Fine-Resolution Hydrologic Modeling of Semiarid River Basins: Preliminary Results from the Upper Rio Grande  

NASA Astrophysics Data System (ADS)

Water resources management and decision making in arid and semiarid regions require scientific knowledge and predictive capability of the physical processes occurring within hydrologic systems at scales sufficient to capture the variability inherent in the resource and its utilization. Our understanding of the interaction between water supply and demand is aided through numerical models that best represent our current knowledge of the hydrologic, ecological and meteorological processes in river basins. To this end, advances in distributed hydrologic modeling over large regional watersheds can aid in providing estimates of water availability and its susceptibility to climate variations, land-cover change and population growth. In this study, we utilize the TIN-based Real-time Integrated Basin Simulator (tRIBS) model to simulate continuous hydrological processes within subbasins of the Upper Río Grande in north-central New Mexico. First, we introduce the distributed model by highlighting the following salient features: (1) coupled unsaturated and saturated zones through a dynamic water table, (2) coupled energy and hydrologic balance at the land surface and (3) topographically-driven soil moisture redistribution, radiation and evapotranspiration. Accurate terrain representation at fine-resolution is achieved through the use of a triangulated irregular network (TIN) terrain model. Second, we present semiarid case studies in model setup, parameterization and continuous operation for the Upper Río Puerco and Jemez River. These river basins provide test cases for the calibration and validation of the tRIBS model through the use of in-situ measurement networks and long-term rainfall and stream gauging records. We will present the catchment hydrological response and its spatial organization by integrating geospatial data on topography, land-surface properties and precipitation obtained from geographic information systems, gauging networks and remote sensing. Although preliminary, our results indicate the potential for using fine-resolution hydrologic models over large semiarid regional watersheds such as the Upper Río Grande.

Wyckoff, R.; Vivoni, E. R.; Rinehart, A.

2004-12-01

26

A preliminary model for predicting heavy metal contaminant loading from an urban catchment  

Microsoft Academic Search

The toxicity of heavy metals to biota in urban catchments has been regarded as a very important non-point source pollution issue. Numerous studies on heavy metal pollution in urban receiving waters have found that metal transport by surface runoff is closely correlated to the partitioning of the metal forms between dissolved and particulate phases, where sediment plays an important role

Yi Yuan; Ken Hall; Carolyn Oldham

2001-01-01

27

Sediment budget for five millennia of tillage in the Rockenberg catchment (Wetterau loess basin, Germany)  

NASA Astrophysics Data System (ADS)

The long-cultivated loess landscapes of central Europe provide the opportunity to explore the long-term perspective on the evolution human-natural sediment systems that are driven by human-caused soil erosion processes. A balance of spatially non-uniform sediment production, sedimentation and delivery was developed to highlight the quantitative dimensions and functioning of anthropogenic sediment redistribution in an undulating loess catchment of temperate Europe. The presented long-term perspective relies on analysing pedostratigraphic and lithostratigraphic field data from 728 corings across ˜10-km2, GIS-based data processing, and the analysis of data uncertainty. For a period of 5000 years of tillage, anthropogenic sediment production equals ˜9425 t ha-1, of which 62% still reside as colluvial sediment on the catchment's hillsides. The valley floors fulfil a sediment-conveyor function through transporting 77% of the sediment received from the hillsides. Whole-catchment yield to the contiguous higher-order valley is 29% of the amount of anthropogenic sediment production. The average catchment-scale depth of soil truncation is 0.64 m while the remaining anthropogenic sediment cover has an average thickness of 0.46 m (effective surface denudation: ˜0.18 m). The long-term integral net erosion rate is ˜0.5 t ha-1 a-1 because of extensive sediment retention on hillsides. The inherited human imprint on the soilscape, eventually, can be judged as beneficial rather than detrimental: the ubiquitous cover of humic colluvia generally is more suitable for intense cultivation than pristine pedostratigraphies. The sediment budget, although build from a historic perspective, also provides a plausible reference for realistic objectives of managing the soil erosion problem in human-natural sediment systems.

Houben, Peter

2012-10-01

28

Simulating wind-affected snow accumulations at catchment to basin scales  

NASA Astrophysics Data System (ADS)

In non-forested mountain regions, wind plays a dominant role in determining snow accumulation and melt patterns. A new, computationally efficient algorithm for distributing the complex and heterogeneous effects of wind on snow distributions was developed. The distribution algorithm uses terrain structure, vegetation, and wind data to adjust commonly available precipitation data to simulate wind-affected accumulations. This research describes model development and application in three research catchments in the Reynolds Creek Experimental Watershed in southwest Idaho, USA. All three catchments feature highly variable snow distributions driven by wind. The algorithm was used to derive model forcings for Isnobal, a mass and energy balance distributed snow model. Development and initial testing took place in the Reynolds Mountain East catchment (0.36 km2) where R2 values for the wind-affected snow distributions ranged from 0.50 to 0.67 for four observation periods spanning two years. At the Upper Sheep Creek catchment (0.26 km2) R2 values for the wind-affected model were 0.66 and 0.70. These R2 values matched or exceeded previously published cross-validation results from regression-based statistical analyses of snow distributions in similar environments. In both catchments the wind-affected model accurately located large drift zones, snow-scoured slopes, and produced melt patterns consistent with observed streamflow. Models that did not account for wind effects produced relatively homogenous SWE distributions, R2 values approaching 0.0, and melt patterns inconsistent with observed streamflow. The Dobson Creek (14.0 km2) application incorporated elevation effects into the distribution routine and was conducted over a two-dimensional grid of 6.67 × 105 pixels. Comparisons with satellite-derived snow-covered-area again demonstrated that the model did an excellent job locating regions with wind-affected snow accumulations. This final application demonstrated that the computational efficiency and modest data requirements of this approach are ideally suited for large-scale operational applications.

Winstral, Adam; Marks, Danny; Gurney, Robert

2013-05-01

29

A semi-distributed integrated flow and nitrogen model for multiple source assessment in catchments (INCA): Part II — application to large river basins in south Wales and eastern England  

Microsoft Academic Search

The integrated nitrogen in catchments (INCA) model is applied to two large river basins, the River Tywi in south Wales and the Great Ouse in eastern England. These two catchments have contrasting hydrogeology, land use and climatic regimes and provide an interesting test of the INCA model. The model is calibrated and validated against hydrological and chemical data for the

P. G Whitehead; E. J Wilson; D Butterfield; K Seed

1998-01-01

30

Catchment-scale biogeochemical filtering: A preliminary evaluation of chemical export in four Experimental Watersheds. (Invited)  

NASA Astrophysics Data System (ADS)

Catchments may be conceptualized as hydrological, biological and geochemical filters, which, forced by precipitation, generate patterns of flow and chemical export. We examine these patterns to obtain insight into the operation of the filters, and consequently into key process interactions within catchments. This study examined patterns of precipitation, flow, nutrient and weathering export from four Experimental Watersheds (Hubbard Brook, Loch Vale, HJ Andrews and Fernow). The following questions guided the study: 1) How was precipitation linked to patterns in stream flow? 2) What patterns emerged with respect to hydrology and chemistry, and how did they vary across sites? 3) Which time scales appeared to be important? Hydrologically, large differences in precipitation-flow patterns emerged at annual and within-year timescales, which appeared to be linked to variability in snowpack density and timing of snowmelt. Across the majority of sites and for a majority of chemical species examined, apparent chemostatic behavior was observed at seasonal timescales, such that the variability in flow-weighted concentration was small in comparison to the variability in hydrological drivers. The variations in the magnitude of this concentration between sub-catchments and between research sites were influenced by geology and atmospheric deposition. Exceptions to the apparent chemostatic response were also observed, notably in bioactive compounds. Potential process controls and decoupling between hydrologic and biogeochemical processes that might lead to such chemostatic behavior are discussed.

Moravec, B. G.; Thompson, S. E.; Aubeneau, A. F.; Ye, S.; Rao, P. C.; Basu, N. B.; Brooks, P. D.; Troch, P. A.

2009-12-01

31

Stable Water Isotope Tracing and Model Evaluation in Large Basins: the `` Special Case'' of Semi-Arid Catchments  

NASA Astrophysics Data System (ADS)

The use of stable water isotopes in hydro-climate monitoring and modelling offers a new means of measuring and parameterizing critical processes. Here we review these specifically for the case of semi-arid basins where water resources are essential for potable supply and agriculture around the world. The verity and performance of existing models is examined using observations and simulations of stable water isotopes in rivers, aquifers and their precedent precipitations. Here we report on the Murray-Darling basin in Australia as one example of the `` special case'' of semi-arid catchments and use these data and results to examine evaluation and refinement of models and predictions on three time-scales: (i) minutes to months, (ii) years to decades and (iii) tens to thousands of years. We find that modelled isotopic depletions become increasingly sensitive to parameterized characteristics as the time period is decreased and/or a significant atmospheric circulation disturbance occurs. Minute to monthly isotope fluxes simulated by land surface schemes and river hydrology models allow comparison of the partition of precipitation between transpiration, run-off and open-water evaporation with isotope observations from 2002 and 2003. A range of atmospheric global circulation models (GCMs) simulations of key hydrological parameters over years to decades reveals poor results for the majority (13 in 20). We show that between 1979 and 1996 modelled groundwater is apparently being `tapped' in many of these GCMs at rates required to allow evaporation to greatly exceed precipitation (Ev>>Pr). Analysis of the `` good"'' versus the `` poor'' hydro-climate models reveals that unwitting application of `` poor'' models to current and future hydrological issues in semi-arid basins generates errors of over 100% in predictions. Isotopes demonstrate that in warm semi-arid regions, in contrast to the behaviour in cool temperate zones, groundwater recharge occurs only when rainfall intensities exceed a threshold suggesting a need to, and a method of, improving aquifer replenishment prediction of tens to thousands of years. Overall, these isotopic results clearly offer novel additions to the traditional tools used in evaluating and improving hydro-climate models and their sub- and super- components. The greatest benefits seem likely to be delivered in semi-arid catchments where subtle isotope tracing and measurement should be combined urgently with gross water flux monitoring to enhance simulation and management schemes.

Henderson-Sellers, A.; Airey, P.; McGuffie, K.; Bradd, J.; Stone, D.

2004-05-01

32

Landslide hazard and risk mapping at catchment scale in the Arno River basin  

Microsoft Academic Search

We present the methodologies adopted and the outcomes obtained in the analysis of landslide risk in the basin of the Arno\\u000a River (Central Italy) in the framework of a project sponsored by the Basin Authority of the Arno River, started in the year\\u000a 2002 and completed at the beginning of 2005. In particular, a complete set of methods and applications

F. Catani; N. Casagli; L. Ermini; G. Righini; G. Menduni

2005-01-01

33

Environmental flows allocation in river basins: Exploring allocation challenges and options in the Great Ruaha River catchment in Tanzania  

NASA Astrophysics Data System (ADS)

Provision for environmental flows is currently becoming a central issue in the debate of integrated water resources management in river basins. However, the theories, concepts and practical applications are still new in most developing countries with challenging situations arising in complex basins with multiple water uses and users and increasing water demands and conflicts exemplified by the Great Ruaha River catchment in Tanzania. The research has shown that a flow of 0.5 1 m3/s for Great Ruaha River through the Ruaha National Park is required to sustain the environment in the park during the dry season. But a question is how can this be achieved? This paper reviews the challenges and suggests some options for achieving environmental water allocation in river basins. The following challenges are identified: (a) the concept of environmental flows is still new and not well known, (b) there is limited data and understanding of the hydrologic and ecological linkages, (c) there is insufficient specialist knowledge and legislative support, (d) there are no storage reservoirs for controlled environmental water releases, and (e) there are contradicting policies and institutions on environmental issues. Notwithstanding these challenges, this paper identifies the options towards meeting environmental water allocation and management: (a) conducting purposive training and awareness creation to communities, politicians, government officials and decision makers on environmental flows, (b) capacity building in environmental flows and setting-up multidisciplinary environmental flows team with stakeholders involvement, (c) facilitating the development of effective local institutions supported by legislation, (d) water harvesting and storage and proportional flow structures design to allow water for the environment, and (e) harmonizing policies and reform in water utilization and water rights to accommodate and ensure water for the environment.

Kashaigili, Japhet J.; Kadigi, Reuben M. J.; Lankford, Bruce A.; Mahoo, Henry F.; Mashauri, Damus A.

34

Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Normalized Atmospheric Deposition for 2002, Ammonium (NH4)  

USGS Publications Warehouse

This tabular data set represents the average normalized (wet) deposition, in kilograms per square kilometer multiplied by 100, of ammonium (NH4) for the year 2002 compiled for every MRB_E2RF1 catchment of the Major River Basins (MRBs, Crawford and others, 2006). Estimates of NH4 deposition are based on National Atmospheric Deposition Program (NADP) measurements (B. Larsen, U.S. Geological Survey, written. commun., 2007). De-trending methods applied to the year 2002 are described in Alexander and others, 2001. NADP site selection met the following criteria: stations must have records from 1995 to 2002 and have a minimum of 30 observations. The MRB_E2RF1 catchments are based on a modified version of the U.S. Environmental Protection Agency's (USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011). Data were compiled for every MRB_E2RF1 catchment for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

35

Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Mean Annual R-factor, 1971-2000  

USGS Publications Warehouse

This tabular data set represents the average annual R-factor, rainfall-runoff erosivity measure, compiled for every MRB_E2RF1 catchment of selected Major River Basins (MRBs, Crawford and others, 2006). The source data are from Christopher Daly of the Spatial Climate Analysis Service, Oregon State University, and George Taylor of the Oregon Climate Service, Oregon State University (2002). The ERF1_2 catchments are based on a modified version of the U.S. Environmental Protection Agency's (USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011). Data were compiled for every MRB_E2RF1 catchment for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

36

Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Average Saturation Excess-Overland Flow, 2002  

USGS Publications Warehouse

This tabular data set represents the average value of saturation overland flow, in percent of total streamflow, compiled for every MRB_E2RF1 catchment of selected Major River Basins (MRBs, Crawford and others, 2006). The source data set is Saturation Overland Flow Estimated by TOPMODEL for the Conterminous United States (Wolock, 2003). The MRB_E2RF1 catchments are based on a modified version of the U.S. Environmental Protection Agency's (USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011). Data were compiled for every MRB_E2RF1 catchment for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

37

Catchment flow estimation using Artificial Neural Networks in the mountainous Euphrates Basin  

NASA Astrophysics Data System (ADS)

Developing an alternative snowmelt runoff modelling tool based on ANN. Running developed models by using basic hydro-meteorological data. Determining the best input data set for modelling snow runoffs in Euphrates Basin. Developing both annual and seasonal ANN based hydrological models.

Yilmaz, A. G.; Imteaz, M. A.; Jenkins, G.

2011-11-01

38

Major ion chemistry, weathering processes and water quality assessment in upper catchment of Damodar River basin, India  

NASA Astrophysics Data System (ADS)

The chemical characteristics of surface, groundwater and mine water of the upper catchment of the Damodar River basin were studied to evaluate the major ion chemistry, geochemical processes controlling water composition and suitability of water for domestic, industrial and irrigation uses. Water samples from ponds, lakes, rivers, reservoirs and groundwater were collected and analysed for pH, EC, TDS, F, Cl, HCO3, SO4, NO3, Ca, Mg, Na and K. In general, Ca, Na, Mg, HCO3 and Cl dominate, except in samples from mining areas which have higher concentration of SO4. Water chemistry of the area reflects continental weathering, aided by mining and other anthropogenic impacts. Limiting groundwater use for domestic purposes are contents of TDS, F, Cl, SO4, NO3 and TH that exceed the desirable limits in water collected from mining and urban areas. The calculated values of SAR, RSC and %Na indicate good to permissible use of water for irrigation. High salinity, %Na, Mg-hazard and RSC values at some sites limit use for agricultural purposes.

Singh, Abhay Kumar; Mondal, G. C.; Kumar, Suresh; Singh, T. B.; Tewary, B. K.; Sinha, A.

2008-04-01

39

Estimation of the Relative Severity of Floods in Small Ungauged Catchments for Preliminary Observations on Flash Flood Preparedness: A Case Study in Korea  

PubMed Central

An increase in the occurrence of sudden local flooding of great volume and short duration has caused significant danger and loss of life and property in Korea as well as many other parts of the World. Since such floods usually accompanied by rapid runoff and debris flow rise quite quickly with little or no advance warning to prevent flood damage, this study presents a new flash flood indexing methodology to promptly provide preliminary observations regarding emergency preparedness and response to flash flood disasters in small ungauged catchments. Flood runoff hydrographs are generated from a rainfall-runoff model for the annual maximum rainfall series of long-term observed data in the two selected small ungauged catchments. The relative flood severity factors quantifying characteristics of flood runoff hydrographs are standardized by the highest recorded maximum value, and then averaged to obtain the flash flood index only for flash flood events in each study catchment. It is expected that the regression equations between the proposed flash flood index and rainfall characteristics can provide the basis database of the preliminary information for forecasting the local flood severity in order to facilitate flash flood preparedness in small ungauged catchments.

Kim, Eung Seok; Choi, Hyun Il

2012-01-01

40

Catchment-scale contaminant transport under changing hydro-climatic conditions in the Aral Sea Drainage Basin, Central Asia  

NASA Astrophysics Data System (ADS)

Dependable projections of future water availability and quality are essential in the management of water resources. Changes in land use, water use and climate can have large impacts on water and contaminant flows across extensive catchments that may contain different administrative regions where shared water resources must be managed. We consider the extensive Aral Sea Drainage Basin (ASDB) and the Amu Darya River Delta in Central Asia, which are currently under severe water stress due to large-scale irrigation expansion. We interpret data on hydro-climatic conditions, main contaminants of surface water and shallow groundwater systems, location of rivers and canal networks, and groundwater flow directions. The data are used together with climate change projections from general circulation models (GCMs) as input to hydrological and (advective) transport modelling. The main goal is to assess how regional transport pathways and travel times have changed, and are likely to change further, in response to past and projected future hydro-climatic changes. More specifically, the hydrological modelling was based on temperature and precipitation change (?T and ?P) results from 65 GCM projections of 21st century conditions (specifically considering time periods around 2025, 2050, and 2100), relative to reference conditions around 1975 (taken from the reference period 1961-1990). Whereas ?T is robustly projected to increase with time, the projected magnitude of ?P differs more among projections for the distant future (2100) than for the near future (2025), with uncertainty remaining even about the direction of change (i.e., positive or negative ?P). However, mainly due to the projected temperature-driven increases in evapotranspiration, ensemble average results show that the Amu Darya river discharge Q in the downstream ASDB is likely to show a decreasing trend throughout the 21st century. Notably, projected changes in the upstream, mountainous regions have a relatively large impact on these Q-projections. For example, the locally created runoff of the downstream region is projected to be maintained or even increase slightly, in contrast to the decreasing Q-trend that reflects an integrated, average response of the entire catchment. A continued drying of surface waters within the Amu Darya river delta implies that advective travel times are increasingly governed by the groundwater system. Such diminished exchanges with surface waters imply increased mean travel times from shallow groundwaters to the (drying) river and drainage canal network by an order of magnitude (from months to years). This can considerably influence mass flow and retention of contaminants in the river delta region, which suffers from e.g. copper, chromium and lead contamination.

Jarsjö, Jerker; Törnqvist, Rebecka; Su, Ye

2013-04-01

41

Quantitative catchment profiling to apportion faecal indicator organism budgets for the Ribble system, the UK's sentinel drainage basin for Water Framework Directive research.  

PubMed

Under the EU Water Framework Directive (WFD) 20/60/EC and the US Federal Water Pollution Control Act 2002 management of water quality within river drainage basins has shifted from traditional point-source control to a holistic approach whereby the overall contribution of point and diffuse sources of pollutants has to be considered. Consequently, there is a requirement to undertake source-apportionment studies of pollutant fluxes within catchments. The inclusion of the Bathing Water Directive (BWD), under the list of 'protected areas' in the WFD places a requirement to control sources of faecal indicator organisms within catchments in order to achieve the objectives of both the BWD (and its revision - 2006/7/EC) and the WFD. This study was therefore initiated to quantify catchment-derived fluxes of faecal indicator compliance parameters originating from both point and diffuse sources. The Ribble drainage basin is the single UK sentinel WFD research catchment and discharges to the south of the Fylde coast, which includes a number of high profile, historically non-compliant, bathing waters. Faecal indicator concentrations (faecal coliform concentrations are reported herein) were measured at 41 riverine locations, the 15 largest wastewater treatment works (WwTWs) and 15 combined sewer overflows (CSOs) across the Ribble basin over a 44-day period during the 2002 bathing season. The sampling programme included targeting rainfall-induced high flow events and sample results were categorised as either base flow or high flow. At the riverine sites, geometric mean faecal coliform concentrations showed statistically significant elevation at high flow compared to base flow. The resultant faecal coliform flux estimates revealed that over 90% of the total organism load to the Ribble Estuary was discharged by sewage related sources during high flow events. These sewage sources were largely related to the urban areas to the south and east of the Ribble basin, with over half the load associated with the relatively small subcatchment of the River Douglas. The majority of this load was attributed to two WwTWs that discharge through a common outfall close to the tidal limit of this catchment. Budgets adjusted to accommodate the impact of proposed UV disinfection of these effluents showed that the load from these sources would be reduced significantly during base flow conditions. However, during high flow events loads would still remain high due to the operation of storm sewage overflows from stormwater retention tanks. The study identified untreated storm sewage spills from urban infrastructure and WwTW stormwater retention tanks as the dominant component of the high flow flux of faecal indicators to receiving waters of the Fylde coast and the associated bathing waters. PMID:18082929

Stapleton, C M; Wyer, M D; Crowther, J; McDonald, A T; Kay, D; Greaves, J; Wither, A; Watkins, J; Francis, C; Humphrey, N; Bradford, M

2007-12-20

42

Bromine species fluxes from Lake Constance’s catchment, and a preliminary lake mass balance  

NASA Astrophysics Data System (ADS)

Bromine was historically termed a cyclic salt in terrestrial freshwater environments due to its perceived conservative cycling between the oceans and the continents. This basic assumption has been challenged recently, with evidence that bromine is involved in dynamic chemical cycles in soils and freshwaters. We present here a study on dissolved bromine species (bromide, organically bound bromine, DOBr) concentrations and fluxes as well as sediment trap bromine levels and fluxes in Lake Constance, a large lake in southern Germany. Water samples were obtained from all major and some minor inflows and outflows over one year, where-after dissolved bromine species were measured by a combination of ICP-MS and ion chromatography coupled to an ICP-MS (IC-ICP-MS). Sediment traps were deployed at two locations for two years with Br, Ti and Zr levels being measured by ?-XRF. 190 t yr -1 of total dissolved bromine (TDBr) was delivered to the lake via 14 rivers and precipitation, with the rivers Alpenrhein (84 t TDBr yr -1) and the Schussen (50 t TDBr yr -1) providing the largest sources. The estimated particulate bromine flux contributed an extra 24-26 t Br yr -1. In comparison, only 40 t TDBr yr -1 was deposited to the lake's catchment by precipitation, and thus ˜80% of the riverine TDBr flux came from soils and rocks. Bromide was the dominant species accounting for, on average, 78% of TDBr concentrations and 93% of TDBr flux to the lake. Despite some high concentrations in the smaller lowland rivers, DOBr was only a minor component of the total riverine bromine flux (˜12 t yr -1, 7%), most of which came from the rivers Schussen, Bregenzer Ach and Argen. In contrast, most of the bromine in the sediment traps was bound to organic matter, and showed a clear seasonal pattern in concentrations, with a maximum in winter and minimum in summer. The summer minimum is thought to be due to dilution of a high Br autochthonous component by low bromine mineral and organic material from the catchment, which is supported by Ti, Zr and Br/C org data. In the lake bromine was irreversibly lost to the sediments, with best flux estimates based on mass-balance and sediment trap data of +50-90 ?g Br m -2 d -1. Overall, it appears that bromine is not simply a cyclic salt in the case of Lake Constance, with a clear geological component and dynamic lacustrine biogeochemistry.

Gilfedder, B. S.; Petri, M.; Wessels, M.; Biester, H.

2011-06-01

43

Mn-oxides and sequestration of heavy metals in a suburban catchment basin of the Chesapeake Bay watershed  

NASA Astrophysics Data System (ADS)

The Chesapeake Bay is greatly impacted by numerous pollutants including heavy metals and understanding the controls on the distribution of heavy metals in the watershed is critical to mitigation and remediation efforts in controlling this type of pollution. Clasts from a stormwater catchment basin draining a subdivision near George Mason University, Fairfax VA (38°50.090°N 78°19.204°W) were investigated using X-ray diffraction (XRD), Scanning electron microcopy (SEM) and energy dispersive spectroscopy (EDS) to determine the nature of Mn-oxide coatings and relationship to bound heavy metals. Mn-oxides are poorly crystalline and occur as subhedral to anhedral platy particles and more rarely as euhedral plates. Micronodules are a commonly observed texture. Chemical compositions of coatings are variable with average major constituent concentrations being Mn (33.38 wt%), Fe (11.88 wt%), Si (7.33 wt%), Al (5.03 wt%), and Ba (0.90 wt%). Heavy metals are found in the coatings with Zn being most prevalent, occurring in approximately 58% of analyses with an average concentration of (0.66 wt%). Minor amounts of Co, Ni, Pb, and Cl are observed. Heavy metals and Cl are interpreted as being derived from road pollution. Mn-oxides can serve as a sequestration mechanism for pollution but may also release heavy metals. Field and laboratory observations indicate Mn-oxides occurring on the surface of the clasts can be mechanically mobilized. This is a mechanism for transporting heavy metals into the Chesapeake Bay watershed. Deicing agents may serve as a mechanism to release heavy metals through cation exchange and increased ionic strength. This is the first detailed mineralogical investigation of Mn-oxides and the roles they may play in pollution in the Chesapeake Bay.

Adams, James P.; Kirst, Robert; Kearns, Lance E.; Krekeler, Mark P. S.

2009-09-01

44

How accurately are climatological characteristics and surface water and energy balances represented for the Colombian Caribbean Catchment Basin?  

NASA Astrophysics Data System (ADS)

In Colombia, the access to climate related observational data is restricted and their quantity is limited. But information about the current climate is fundamental for studies on present and future climate changes and their impacts. In this respect, this information is especially important over the Colombian Caribbean Catchment Basin (CCCB) that comprises over 80 % of the population of Colombia and produces about 85 % of its GDP. Consequently, an ensemble of several datasets has been evaluated and compared with respect to their capability to represent the climate over the CCCB. The comparison includes observations, reconstructed data (CPC, Delaware), reanalyses (ERA-40, NCEP/NCAR), and simulated data produced with the regional climate model REMO. The capabilities to represent the average annual state, the seasonal cycle, and the interannual variability are investigated. The analyses focus on surface air temperature and precipitation as well as on surface water and energy balances. On one hand the CCCB characteristics poses some difficulties to the datasets as the CCCB includes a mountainous region with three mountain ranges, where the dynamical core of models and model parameterizations can fail. On the other hand, it has the most dense network of stations, with the longest records, in the country. The results can be summarised as follows: all of the datasets demonstrate a cold bias in the average temperature of CCCB. However, the variability of the average temperature of CCCB is most poorly represented by the NCEP/NCAR dataset. The average precipitation in CCCB is overestimated by all datasets. For the ERA-40, NCEP/NCAR, and REMO datasets, the amplitude of the annual cycle is extremely high. The variability of the average precipitation in CCCB is better represented by the reconstructed data of CPC and Delaware, as well as by NCEP/NCAR. Regarding the capability to represent the spatial behaviour of CCCB, temperature is better represented by Delaware and REMO, while precipitation is better represented by Delaware. Among the three datasets that permit an analysis of surface water and energy balances (REMO, ERA-40, and NCEP/NCAR), REMO best demonstrates the closure property of the surface water balance within the basin, while NCEP/NCAR does not demonstrate this property well. The three datasets represent the energy balance fairly well, although some inconsistencies were found in the individual balance components for NCEP/NCAR.

Hoyos, Isabel; Baquero-Bernal, Astrid; Hagemann, Stefan

2013-02-01

45

How accurately are climatological characteristics and surface water and energy balances represented for the Colombian Caribbean Catchment Basin?  

NASA Astrophysics Data System (ADS)

In Colombia, the access to climate related observational data is restricted and their quantity is limited. But information about the current climate is fundamental for studies on present and future climate changes and their impacts. In this respect, this information is especially important over the Colombian Caribbean Catchment Basin (CCCB) that comprises over 80 % of the population of Colombia and produces about 85 % of its GDP. Consequently, an ensemble of several datasets has been evaluated and compared with respect to their capability to represent the climate over the CCCB. The comparison includes observations, reconstructed data (CPC, Delaware), reanalyses (ERA-40, NCEP/NCAR), and simulated data produced with the regional climate model REMO. The capabilities to represent the average annual state, the seasonal cycle, and the interannual variability are investigated. The analyses focus on surface air temperature and precipitation as well as on surface water and energy balances. On one hand the CCCB characteristics poses some difficulties to the datasets as the CCCB includes a mountainous region with three mountain ranges, where the dynamical core of models and model parameterizations can fail. On the other hand, it has the most dense network of stations, with the longest records, in the country. The results can be summarised as follows: all of the datasets demonstrate a cold bias in the average temperature of CCCB. However, the variability of the average temperature of CCCB is most poorly represented by the NCEP/NCAR dataset. The average precipitation in CCCB is overestimated by all datasets. For the ERA-40, NCEP/NCAR, and REMO datasets, the amplitude of the annual cycle is extremely high. The variability of the average precipitation in CCCB is better represented by the reconstructed data of CPC and Delaware, as well as by NCEP/NCAR. Regarding the capability to represent the spatial behaviour of CCCB, temperature is better represented by Delaware and REMO, while precipitation is better represented by Delaware. Among the three datasets that permit an analysis of surface water and energy balances (REMO, ERA-40, and NCEP/NCAR), REMO best demonstrates the closure property of the surface water balance within the basin, while NCEP/NCAR does not demonstrate this property well. The three datasets represent the energy balance fairly well, although some inconsistencies were found in the individual balance components for NCEP/NCAR.

Hoyos, Isabel; Baquero-Bernal, Astrid; Hagemann, Stefan

2013-09-01

46

Preliminary Hazards Analysis of K-Basin Fuel Encapsulation and Storage  

SciTech Connect

This Preliminary Hazards Analysis (PHA) systematically examines the K-Basin facilities and their supporting systems for hazards created by abnormal operating conditions and external events (e.g., earthquakes) which have the potential for causing undesirable consequences to the facility worker, the onsite individual, or the public. The operational activities examined are fuel encapsulation, fuel storage and cooling. Encapsulation of sludges in the basins is not examined. A team of individuals from Westinghouse produced a set of Hazards and Operability (HAZOP) tables documenting their examination of abnormal process conditions in the systems and activities examined in K-Basins. The purpose of this report is to reevaluate and update the HAZOP in the original Preliminary Hazard Analysis of K-Basin Fuel Encapsulation and Storage originally developed in 1991.

Strickland, G.C.

1994-08-19

47

Effects of catchment and riparian landscape setting on water chemistry and seasonal evolution of water quality in the upper Han River basin, China.  

PubMed

Six-year (2005-2010) evolution of water chemistry (Cl(-), NO(3)(-), SO(4)(2-), HCO(3)(-), Na(+), K(+), Ca(2+) and Mg(2+)) and their interactions with morphological properties (i.e., slope and area), land cover, and hydrological seasonality were examined to identify controlling factors and processes governing patterns of stream water quality in the upper Han River, China. Correlation analysis and stepwise multiple regression models revealed significant correlations between ions (i.e., Cl(-), SO(4)(2-), Na(+) and K(+)) and land cover (i.e., vegetation and bare land) over the entire catchment in both high- and low-flow periods, and in the buffer zone the correlation was much more stronger in the low-flow period. Catchment with steeper slope (>15°) was negatively correlated with major ions, largely due to multicollinearity of basin characteristics. Land cover within the buffer zone explained slightly less of major elements than at catchment scale in the rainy season, whereas in the dry season, land cover along the river networks in particular this within 100 m riparian zone much better explained major elements rather than this over the entire catchment. Anthropogenic land uses (i.e., urban and agriculture) however could not explain water chemical variables, albeit EC, TDS, anthropogenic markers (Cl(-), NO(3)(-), SO(4)(2)), Na(+), K(+) and Ca(2+) significantly increased during 2005-2010, which was corroborated by principal component analyses (PCA) that indicated anthropogenic inputs. Observations demonstrated much higher solute concentrations in the industrial-polluted river. Our results suggested that seasonal evolution of water quality in combined with spatial analysis at multiple scales should be a vital part of identifying the controls on spatio-temporal patterns of water quality. PMID:23349700

Li, Siyue; Xia, Xiaoling; Tan, Xiang; Zhang, Quanfa

2013-01-22

48

Effects of Catchment and Riparian Landscape Setting on Water Chemistry and Seasonal Evolution of Water Quality in the Upper Han River Basin, China  

PubMed Central

Six-year (2005–2010) evolution of water chemistry (Cl?, NO3?, SO42?, HCO3?, Na+, K+, Ca2+ and Mg2+) and their interactions with morphological properties (i.e., slope and area), land cover, and hydrological seasonality were examined to identify controlling factors and processes governing patterns of stream water quality in the upper Han River, China. Correlation analysis and stepwise multiple regression models revealed significant correlations between ions (i.e., Cl?, SO42?, Na+ and K+) and land cover (i.e., vegetation and bare land) over the entire catchment in both high- and low-flow periods, and in the buffer zone the correlation was much more stronger in the low-flow period. Catchment with steeper slope (>15°) was negatively correlated with major ions, largely due to multicollinearity of basin characteristics. Land cover within the buffer zone explained slightly less of major elements than at catchment scale in the rainy season, whereas in the dry season, land cover along the river networks in particular this within 100 m riparian zone much better explained major elements rather than this over the entire catchment. Anthropogenic land uses (i.e., urban and agriculture) however could not explain water chemical variables, albeit EC, TDS, anthropogenic markers (Cl?, NO3?, SO42), Na+, K+ and Ca2+ significantly increased during 2005–2010, which was corroborated by principal component analyses (PCA) that indicated anthropogenic inputs. Observations demonstrated much higher solute concentrations in the industrial-polluted river. Our results suggested that seasonal evolution of water quality in combined with spatial analysis at multiple scales should be a vital part of identifying the controls on spatio-temporal patterns of water quality.

Li, Siyue; Xia, Xiaoling; Tan, Xiang; Zhang, Quanfa

2013-01-01

49

Preliminary stratigraphic and paleomagnetic results from Neogene basins across the Anatolian Plateau (Turkey).  

NASA Astrophysics Data System (ADS)

An integrated paleomagnetic and stratigraphic study on Neogene basins across the Anatolian Plateau was carried out. This study is developed within the VAMP (Vertical Anatolian Movement Project), an interdisciplinary project aimed to the recent tectonic evolution of the central Anatolian Plateau. The studied areas are located in southern Turkey (Adana, Mut and Ermenek basins) and in northern Turkey (Kazan, Çankiri, Kastamonu, Boyabat and Sinop basins). For paleomagnetic analyses we sampled 1062 standard cylindrical samples from 13 stratigraphic sections, and 746 samples for paleontological analysis were taken from the same sections. AMS (Anisotropy of Magnetic Susceptibility), magnetic mineralogy and paleomagnetic polarity data are presented together with the results of the integrated stratigraphic analyses. In the Southern Turkey basins preliminary results show the diffuse presence of authigenic iron sulphides, together with magnetite, as main magnetic carriers. In these sections the iron-sulphides Characteristic Natural Magnetization (ChRM) component is characterized by inconsistent polarity record, suggesting that iron-sulphides have a late diagenetic origin. Conversely, magnetite bearing sediments show more reliable results in term of magnetic polarity interpretations. Preliminary stratigraphic and paleomagnetic results from the southern margin of the plateau allow us both to refine the stratigraphy for the late Miocene of the Adana Basin and to better constrain the age of the youngest marine deposits of the Mut and Ermenek basins. In the late Miocene of the Adana Basin evidence of the Messinian salinity crisis led to a new stratigraphic framework specially for the Messinian-Pliocene interval. Thick fluvial conglomerates from the uppermost Messinian deposits of the Adana Basin, which could be linked to the activation of the southern margin of the plateau, allow us to constrain at about 5.4 Ma the uplift of the central Anatolian Plateau. On the other hand, the preliminary results of the micropaleontological analyses carried out on the higher marine deposits sampled in the northern part of the Ermenek Basin (Basyayla section, 1840 m a.s.l.) point to a post-Tortonian age for the plateau uplift. The age of the basins at the northern margin of the plateau are very poor constrained, except for that basins containing vertebrate-bearing continental deposits. However, from a palaeogeographic point of view, our preliminary data suggest a possible Tortonian connection between the Çankiri Basin and the Paratethyan realm. This presentation was supported by the EUROCORE programme TOPO-EUROPE of the European Science Foundation.

Lucifora, Stella; Cifelli, Francesca; Mazzini, Ilaria; Cosentino, Domenico; Mattei, Massimo; Cipollari, Paola; Gliozzi, Elsa; Palolo Cavinato, Gian

2010-05-01

50

High frequency variations of water flux and sediment discharge during the Little Ice Age (1586–1725 AD) in the Rhône Delta (Mediterranean France). Relationship to the catchment basin  

Microsoft Academic Search

During the 17th and 18th centuries, the Rhône delta recorded high frequency fluctuations in water and sediment influx. These variations resulted from the drastic climatic changes that took place during the Little Ice Age, which were intensified by dense land settlement in the catchment basin. The use of complementary types of information (iconographic and textual archives, photo-interpretation of traces of

G. Arnaud-Fassetta; M. Provansal

1999-01-01

51

Preliminary design report for the K basins integrated water treatment system  

SciTech Connect

This Preliminary Design Report (PDR) provides a revised concept for the K Basins Integrated Water Treatment Systems (IWTS). This PDR incorporates the 11 recommendations made in a May 1996 Value Engineering session into the Conceptual Design, and provides new flow diagrams, hazard category assessment, cost estimate, and schedule for the IWTS Subproject.

Pauly, T.R., Westinghouse Hanford

1996-08-12

52

Paired Catchment Modeling Study for a Monsoon Flood Event in Neighboring Semi-Arid Basins, New Mexico  

Microsoft Academic Search

Flooding in ephemeral stream networks can significantly impact channel geomorphology, sediment transport, biogeochemical cycles, and water availability for consumptive and recreational use. In order to better understand the spatial patterns of flooding, distributed models may provide an opportunity for further investigation of rainfall-runoff dynamics in headwater semi-arid catchments including flood generation in ungauged portions of a watershed. For example, the

R. L. Wyckoff; E. R. Vivoni

2005-01-01

53

A Preliminary OBS Data Analysis in the West Philippine Basin  

NASA Astrophysics Data System (ADS)

During Leg 4 of TAIGER MCS/OBS experiment (June-July 2009), a long profile of 550 km was shot by R/V Langseth in the West Philippine Basin. We placed 28 short-period OBSs at a station-to-station distance of 15 km along this profile. This profile was designed to be 90 degree to the spreading fabric as previously mapped by the multi-beam echo-sounding data. Because of the Typhoon Molave, R/V Langseth shot 3 times to complete the whole track. The large air-gun sources and over-lapping shoots allow us to place the shoot geometry at either a single-combined profile or 3 separated profiles. We are investigating the best result from these two different geometry models. The age-depth relationship shows that the bathymetry is deeper toward the north, the Ryukyu Subduction Zone, however, the magnetic modeling suggest the older West Philippine Basin crust is in the south. An initial OBS model indicates the Pn arrival can be traced up to 80 more km away from the OBS station center. More interpretations will be elucidated for the crustal evolution of the West Philippine Basin in the near future. Drs. Shu-Kun Hsu and Kirk MacIntash were the chief scientists of Leg 4 TAIGER cruise on board R/V Langseth. We provided several ships to support the OBS experiment. These data were collected by a multi-ship operation.

Lai, W.; Huang, W.; Lee, C.

2009-12-01

54

Preliminary assessment of fluxes of priority pollutants in stormwater discharges in two urban catchments in Lyon, France  

Microsoft Academic Search

In urban catchments, diffuse stormwater discharges from both separate and combined sewers contribute significantly to the contamination of water bodies by numerous pollutants, including the priority substances listed in the European Water Framework Directive. Whereas concentrations and loads of traditional pollutants (suspended solids, BOD, COD, nutriments…) in stormwater discharges are well documented, very few information is available on the presence,

C. Becouze; A. Dembélé; M Coquery

55

Environmental flows allocation in river basins: Exploring allocation challenges and options in the Great Ruaha River catchment in Tanzania  

Microsoft Academic Search

Provision for environmental flows is currently becoming a central issue in the debate of integrated water resources management in river basins. However, the theories, concepts and practical applications are still new in most developing countries with challenging situations arising in complex basins with multiple water uses and users and increasing water demands and conflicts exemplified by the Great Ruaha River

Japhet J. Kashaigili; Reuben M. J. Kadigi; Bruce A. Lankford; Henry F. Mahoo; Damus A. Mashauri

2005-01-01

56

Las Vegas Basin Seismic Response Project: Preliminary Results From Seismic Refraction Experiments, Las Vegas, NV.  

NASA Astrophysics Data System (ADS)

In May and September 2002, seismic refraction data were acquired in the Las Vegas basin. Located in the southern Basin and Range province, the cities of Las Vegas, North Las Vegas, and Henderson sit atop a fault-bounded basin with a depth of up to 5 km and basin dimensions of roughly 60 km wide (east-west) by 50 km in length (north-south). Previous isostatic gravity, seismic reflection, and aeromagnetic studies indicate that a series of sub-basins exist beneath the unconsolidated basin fill, with the deepest sub-basin occurring 5 km west of the fault block bounding the eastern edge of the basin (Frenchman Mountain). The basin is significantly deeper along its northern extremity, following the path of the fault block bounding the northern edge of the basin (Las Vegas Valley Shear Zone), and along the western edge of Frenchman Mountain. Recent, paleoseismic studies have indicated that faults in the Las Vegas region have the potential for an earthquake of M6.5 to 7.0. It is estimated that a M6.9 earthquake in the basin could produce about 11 billion dollars in damage and a significant number of deaths and/or injuries. In addition, an equivalent or larger event in the Death Valley fault zone, 150 km distance, would also be devastating to the metropolitan area of approximately 1.5 million residents. Therefore, it is essential to understand the seismic hazard posed to the Las Vegas region. This project is part of a larger collaborative effort to characterize the basin and its response to ground shaking. The University of Nevada, Las Vegas with assistance from the University of Texas at El Paso, students from UNLV and UTEP, volunteers from the community and several students from Centennial High school deployed 432 portable seismic recorders ("Texans") throughout the valley. Shot point locations were located at three quarries in the valley, one to the north, one to the east and one to the southwest. The profiles cross the Las Vegas Valley Shear zone as well as a prominent NW/SE trending step in the basin floor across which the basement drops from 2 to 4 km in depth. In addition, the profiles cross several Quaternary fault scarps, which have recently been identified as tectonic in origin. Preliminary analyses of the seismic refraction data indicate that the basin has an average P-wave velocity of 4.5 km/s and is in agreement with the estimated basin depths from isostatic gravity studies (2 to 5 km depth). Both tomographic inversion and forward modeling techniques are being used to analyze these data. These data will be used to produce a velocity model of the basin and image the basin/bedrock contact. In addition, these data will be integrated into a community model, which is being produced by the Las Vegas Basin Seismic Response working group to further assess the site response of the basin.

Zaragoza, S. A.; Snelson, C. M.; Harder, S. H.; Kaip, G.; Luke, B.; Buck, B. J.; Hanson, A. D.

2002-12-01

57

Permian Basin, Texas: Volume 1, Text: Final preliminary design report  

SciTech Connect

This report is a description of the preliminary design for an Exploratory Shaft Facility (ESF) at the proposed 49 acre site located 21 miles north of Hereford, Texas in Deaf Smith County. Department of Energy must conduct in situ testing at depth to ascertain the engineering and environmental suitability of the site for further consideration for nuclear waste repository development. The ESF includes the construction of two 12-ft diameter engineered shafts for accessing the bedded salt horizon to conduct in situ tests to ascertain if the site should be considered a candidate site for the first High Level Nuclear Waste Repository. This report includes pertinent engineering drawings for two shafts and all support facilities necessary for shaft construction and testing program operation. Shafts will be constructed by conventional drill-and-blast methods employing ground freezing prior to shaft construction to stabilize the existing groundwater and soil conditions at the site. A watertight liner and seal system will be employed to prevent intermingling of aquifers and provide a stable shaft throughout its design life. 38 refs., 37 figs., 14 tabs.

Not Available

1988-01-01

58

Climate change impact on water and salt balances: an assessment of the impact of climate change on catchment salt and water balances in the Murray-Darling Basin, Australia  

Microsoft Academic Search

Climate change has potentially significant implications for hydrology and the quantity and quality of water resources. This\\u000a study investigated the impacts of climate change and revegetation on water and salt balance, and stream salt concentration\\u000a for catchments within the Murray-Darling Basin, Australia. The Biophysical Capacity to Change model was used with climate\\u000a change scenarios obtained using the CSIRO DARLAM 125

Jenet Austin; Lu Zhang; Roger N. Jones; Warrick Dawes; Peter Hairsine

2010-01-01

59

Variations of temperature and hydrologic regimes of the region of Ladoga Lake catchment basin in the 20th and 21st centuries according to data of modern climate models  

Microsoft Academic Search

In the region of the Ladoga Lake catchment basin, we perform data analysis on a set of different modern climate models with different Intergovernmental Panel on Climate Change (IPCC) scenarios in the 20th and 21st centuries; this set includes global models such as ECHAM4\\/OPYC3 (Max Planck Institute for Meteorology, Germany), HadCM3 (Hadley Centre Coupled Model, England), and RCAO (Rossby Centre

V. A. Rumyantsev; L. K. Efimova; G. S. Golitsyn; V. Ch. Khon

2010-01-01

60

Variations of temperature and hydrologic regimes of the region of Ladoga Lake catchment basin in the 20th and 21st centuries according to data of modern climate models  

Microsoft Academic Search

In the region of the Ladoga Lake catchment basin, we perform data analysis on a set of different modern climate models with\\u000a different Intergovernmental Panel on Climate Change (IPCC) scenarios in the 20th and 21st centuries; this set includes global\\u000a models such as ECHAM4\\/OPYC3 (Max Planck Institute for Meteorology, Germany), HadCM3 (Hadley Centre Coupled Model, England),\\u000a and RCAO (Rossby Centre

V. A. Rumyantsev; L. K. Efimova; G. S. Golitsyn; V. Ch. Khon

2010-01-01

61

Preparing public participation at the catchment level: comparison of three methodologies applied to the Hérault river basin.  

PubMed

Public participation in water resources management has increasingly been recommended to increase the effectiveness and the acceptability of proposed water management projects and plans. Different levels of public participation are possible depending on the governance context. This paper reports on the practical implementation of three different methodologies in the Hérault river catchment (France). The analysis of public view points, carried out using a quantitative opinion survey and focus groups, reveals important information needs which have to be fulfilled for any further consultation to be efficient. A complementary analysis of stakeholders' opinions, carried out through semi-structured interviews also highlights the need to construct a common knowledge base between stakeholders, expert and scientists. This is seen as a prerequisite to implementing more elaborated forms of participation. PMID:16477969

Loubier, S; Rinaudo, J D; Garin, P; Boutet, A

2005-01-01

62

Macroinvertebrate Index of Biotic Integrity (M-IBI) for monitoring rivers in the upper catchment of Lake Victoria Basin, Kenya  

Microsoft Academic Search

The water quality of many streams in Lake Victoria Basin, Kenya is affected by agricultural intensification, municipal and industrial effluent, as well as water abstraction, livestock and deforestation. Management efforts have been hampered by lack of clear standards against which to judge the degree of environmental degradation. To achieve this goal, a macroinvertebrate-based Index of Biotic Integrity was developed to

Phillip Okoth Raburu; Frank Onderi Masese; Christopher Aura Mulanda

2009-01-01

63

Quantifying uncertainty in the impacts of climate change on river discharge in sub-catchments of the Yangtze and Yellow River Basins, China  

NASA Astrophysics Data System (ADS)

Quantitative evaluations of the impacts of climate change on water resources are primarily constrained by uncertainty in climate projections from GCMs. In this study we assess uncertainty in the impacts of climate change on river discharge in two catchments of the Yangtze and Yellow River Basins that feature contrasting climate regimes (humid and semi-arid). Specifically we quantify uncertainty associated with GCM structure from a subset of CMIP3 AR4 GCMs (HadCM3, HadGEM1, CCSM3.0, IPSL, ECHAM5, CSIRO, CGCM3.1), SRES emissions scenarios (A1B, A2, B1, B2) and prescribed increases in global mean air temperature (1 °C to 6 °C). Climate projections, applied to semi-distributed hydrological models (SWAT 2005) in both catchments, indicate trends toward warmer and wetter conditions. For prescribed warming scenarios of 1 °C to 6 °C, linear increases in mean annual river discharge, relative to baseline (1961-1990), for the River Xiangxi and River Huangfuchuan are +9% and 11% per +1 °C respectively. Intra-annual changes include increases in flood (Q05) discharges for both rivers as well as a shift in the timing of flood discharges from summer to autumn and a rise (24 to 93%) in dry season (Q95) discharge for the River Xiangxi. Differences in projections of mean annual river discharge between SRES emission scenarios using HadCM3 are comparatively minor for the River Xiangxi (13 to 17% rise from baseline) but substantial (73 to 121%) for the River Huangfuchuan. With one minor exception of a slight (-2%) decrease in river discharge projected using HadGEM1 for the River Xiangxi, mean annual river discharge is projected to increase in both catchments under both the SRES A1B emission scenario and 2° rise in global mean air temperature using all AR4 GCMs on the CMIP3 subset. For the River Xiangxi, there is substantial uncertainty associated with GCM structure in the magnitude of the rise in flood (Q05) discharges (-1 to 41% under SRES A1B and -3 to 41% under 2° global warming) and dry season (Q95) discharges (2 to 55% under SRES A1B and 2 to 39% under 2° global warming). For the River Huangfuchuan, all GCMs project a rise in the Q05 flow but there is substantial uncertainty in the magnitude of this rise (7 to 70% under SRES A1B and 2 to 57% under 2° global warming). Differences in the projected hydrological changes are associated with GCM structure in both catchments exceed uncertainty in emission scenarios. Critically, estimated uncertainty in projections of mean annual flows is less than that calculated for extreme (Q05, Q95) flows. The common approach of reporting of climate change impacts on river in terms of mean annual flows masks the magnitude of uncertainty in flows that are of most importance to water management.

Xu, H.; Taylor, R. G.; Xu, Y.

2011-01-01

64

Quantifying uncertainty in the impacts of climate change on river discharge in sub-catchments of the River Yangtze and Yellow Basins, China  

NASA Astrophysics Data System (ADS)

Quantitative evaluations of the impacts of climate change on water resources are primarily constrained by uncertainty in climate projections from GCMs. In this study we assess uncertainty in the impacts of climate change on river discharge in two catchments of the River Yangtze and Yellow Basins that feature contrasting climate regimes (humid and semi-arid). Specifically we quantify uncertainty associated with GCM structure from a subset of CMIP3 AR4 GCMs (HadCM3, HadGEM1, CCSM3.0, IPSL, ECHAM5, CSIRO, CGCM3.1), SRES emissions scenarios (A1B, A2, B1, B2) and prescribed increases in global mean air temperature (1 °C to 6 °C). Climate projections, applied to semi-distributed hydrological models (SWAT 2005) in both catchments, indicate trends toward warmer and wetter conditions. For prescribed warming scenarios of 1 °C to 6 °C, linear increases in mean annual river discharge, relative to baseline (1961-1990), for the River Xiangxi and River Huangfuchuan are +9% and 11% per +1 °C, respectively. Intra-annual changes include increases in flood (Q05) discharges for both rivers as well as a shift in the timing of flood discharges from summer to autumn and a rise (24 to 93%) in dry season (Q95) discharge for the River Xiangxi. Differences in projections of mean annual river discharge between SRES emission scenarios using HadCM3 are comparatively minor for the River Xiangxi (13% to 17% rise from baseline) but substantial (73% to 121%) for the River Huangfuchuan. With one minor exception of a slight (-2%) decrease in river discharge projected using HadGEM1 for the River Xiangxi, mean annual river discharge is projected to increase in both catchments under both the SRES A1B emission scenario and 2° rise in global mean air temperature using all AR4 GCMs on the CMIP3 subset. For the River Xiangxi, there is great uncertainty associated with GCM structure in the magnitude of the rise in flood (Q05) discharges (-1% to 41% under SRES A1B and -3% to 41% under 2° global warming) and dry season (Q95) discharges (2% to 55% under SRES A1B and 2% to 39% under 2° global warming). For the River Huangfuchuan, all GCMs project a rise in the Q05 flow but there is substantial uncertainty in the magnitude of this rise (7% to 70% under SRES A1B and 2% to 57% under 2° global warming). Greatest differences in the projected hydrologic changes are associated with GCMs in both catchments than emission scenarios and climate sensitivity. Critically, estimated uncertainty in projections of mean annual flows is less than that calculated for extreme (Q05, Q95) flows. This research suggest that the common approach of reporting of climate change impacts on river in terms of mean annual flows may mask the magnitude of uncertainty in flows of most importance to water managers.

Xu, H.; Taylor, R. G.; Xu, Y.

2010-09-01

65

Controls on hydrologic similarity: role of nearby gauged catchments for prediction at an ungauged catchment  

NASA Astrophysics Data System (ADS)

Prediction of streamflows at ungauged catchments requires transfer of hydrologic information (e.g., model parameters, hydrologic indices, streamflow values) from gauged (donor) to ungauged (receiver) catchments. One of the most reliable metrics for selection of ideal donor catchments is the spatial proximity between donor and receiver catchments. However, it is not clear whether information transfer among nearby catchments is suitable across a wide range of climatic and geographic regions. We examine this issue using the data from 756 catchments within the continental United States. Each catchment is considered ungauged in turn and daily streamflow is simulated through distance-based interpolation of streamflows from neighboring catchments. Results show that distinct geographic regions exist in US where transfer of streamflow values from nearby catchments is useful for retrospective prediction of daily streamflow at ungauged catchments. Specifically, the high predictability catchments (Nash-Sutcliffe efficiency NS > 0.7) are confined to the Appalachian Mountains in eastern US, the Rocky Mountains, and the Cascade Mountains in the Pacific Northwest. Low predictability catchments (NS < 0.3) are located mostly in the drier regions west of Mississippi river, which demonstrates the limited utility of gauged catchments in those regions for predicting at ungauged basins. The results suggest that high streamflow similarity among nearby catchments (and therefore, good predictability at ungauged catchments) is more likely in humid runoff-dominated regions than in dry evapotranspiration-dominated regions. We further find that higher density and/or closer distance of gauged catchments near an ungauged catchment does not necessarily guarantee good predictability at an ungauged catchment.

Patil, S.; Stieglitz, M.

2011-10-01

66

Controls on hydrologic similarity: role of nearby gauged catchments for prediction at an ungauged catchment  

NASA Astrophysics Data System (ADS)

Prediction of streamflow at ungauged catchments requires transfer of hydrologic information (e.g., model parameters, hydrologic indices, streamflow values) from gauged (donor) to ungauged (receiver) catchments. A common metric used for the selection of ideal donor catchments is the spatial proximity between donor and receiver catchments. However, it is not clear whether information transfer among nearby catchments is suitable across a wide range of climatic and geographic regions. We examine this issue using the data from 756 catchments within the continental United States. Each catchment is considered ungauged in turn and daily streamflow is simulated through distance-based interpolation of streamflows from neighboring catchments. Results show that distinct geographic regions exist in US where transfer of streamflow values from nearby catchments is useful for retrospective prediction of daily streamflow at ungauged catchments. Specifically, the high predictability catchments (Nash-Sutcliffe efficiency NS > 0.7) are confined to the Appalachian Mountains in eastern US, the Rocky Mountains, and the Cascade Mountains in the Pacific Northwest. Low predictability catchments (NS < 0.3) are located mostly in the drier regions west of Mississippi river, which demonstrates the limited utility of gauged catchments in those regions for predicting at ungauged basins. The results suggest that high streamflow similarity among nearby catchments (and therefore, good predictability at ungauged catchments) is more likely in humid runoff-dominated regions than in dry evapotranspiration-dominated regions. We further find that higher density and/or closer distance of gauged catchments near an ungauged catchment does not necessarily guarantee good predictability at an ungauged catchment.

Patil, S.; Stieglitz, M.

2012-02-01

67

Nitrogen deposition and leaching from two forested catchments in Southwest China--preliminary data and research needs.  

PubMed

Increased nitrogen deposition has resulted in increased nitrogen pools and nitrogen leaching in European and North American forest soils. The development in Asia in general, and China in particular, suggests increased deposition of reduced nitrogen from changes in agricultural practices and of oxidized nitrogen from rapid growth of the transportation sector. Decreased nitrogen retention in forested areas in the future may cause increased NO3- leaching and, thus, acidification and eutrophication in surface waters. The differences in climate, ecosystems, land use, and deposition history make direct application of knowledge from studies in Europe and North America difficult. In Southwest China the potential for nitrogen mobilization from forest soils may be high because of the warm and humid climate, resulting in high decomposition rates of soil organic matter. However, there are very few data available for quantifying the suspected potential for increased nitrogen leaching in forest ecosystems. Here we present data from two forested catchments, dominated by Masson pine (Pinus massoniana), near Guiyang and Chongqing, respectively, in Southwest China. The present nitrogen deposition is moderate, estimated in the range from 10 to 40 kg N ha(-1) year(-1). The C/N ratios of the soils are generally below 15. Nitrate concentrations in soil water are rather variable in space, with highest values of several hundred microequivalents per liter. The turnover rate of nitrogen in the forest ecosystem is quite high compared to the atmospheric deposition rate. At present, nitrate runoff from the catchments is low and intermediate in Guiyang and Chongqing, respectively. More research is needed to improve our ability to predict future nitrogen leaching from subtropical Asian coniferous forests. PMID:12805807

Larssen, T; Mulder, J; Wang, Y; Chen, X; Xiao, J; Zhao, D

2001-11-15

68

Development of a spatial database for large-scale catchment management: Geology, soils, and landuse in the Namoi Basin, Australia  

Microsoft Academic Search

The ArcInfo Geographical Information System (GIS) was used to develop spatial databases for recording spatial data. The databases developed in this study provide a graphic and mapping display interface to assist the management of the Namoi Basin in New South Wales, Australia. In addition, the databases are used in the investigation of the impacts of spatio-temporal changes in landuse\\/management on

S. D. Gray

1999-01-01

69

Potential for chemical transport beneath a storm-runoff recharge (retention) basin for an industrial catchment in Fresno, California  

USGS Publications Warehouse

A wide variety of chemicals from urban runoff were found at elevated concentrations in sediment that accumulated in a storm-runoff recharge basin in an industrial part of the city of Fresno. The chemicals include as many as 20 inorganic elements and about the same number of organic compounds, primarily organochlorine pesticides and polycyclic aromatic hydrocarbons. Most of these contaminants were found to be sorbed to the upper 4 centimeters of sediment, which also is the maximum depth to which atmospheric lead-210 penetrated. None of the contaminants were detected above background concentrations in the sediment at depths greater than 16 centimeters. In shallow sediment, zinc is the inorganic element that showed the greatest enrichment; its concentration was 38 times higher in surface sediment (0-1 centimeter) than in deeper strata (below 16 centi- meters). Organic carbon enrichment in the surface sediment was nearly 1,000 times. Although batch- elutriation experiments demonstrated the potential for leaching of contaminants attached to sediments, a sharp decrease in concentrations with increasing sediment depth, and the extremely low level of contaminants in two monitor wells adjacent to the basin, confirmed the absence of contaminant transport to the water table. Continued long-term protection for ground water is afforded by an approximately 8-meter-thick unsaturated zone beneath the basin. On the basis of its hundredfold-higher concentration in the recharge pond then in ground water, zinc is indicated as the most sensitive surrogate for monitoring possible ground-water degradation by inorganic cations.

Schroeder, R. A.

1995-01-01

70

Viking bistatic radar observations of the hellas basin on Mars: preliminary results.  

PubMed

Preliminary reduction of Viking bistatic radar data gives root-mean-square surface slopes in the Hellas basin on Mars of about 4 degrees on horizontal scales averaged over 10 centimeters to 100 meters. This roughness decreases slightly with position along the ground track, south to north. The dielectric constant in this area appears to be approximately 3.1, greater than the martian average. These values are characteristic of lunar maria and are similar to those found near the Viking lander site in Chryse with the use of Earth-based radar. PMID:17840509

Simpson, R A; Tyler, G L; Brenkle, J P; Sue, M

1979-01-01

71

Isotope Tracers in Catchment Hydrology  

NASA Astrophysics Data System (ADS)

The drainage basin has been a fundamental unit of study in hydrology and geomorphology throughout the modern era of these Earth sciences. The basin, or catchment, is a convenient unit because it typically is well defined topographically, can be studied as a series of nested units of increasing size, and is an open system for which inputs and outputs of mass and energy can be defined and measured. Small catchments have been the “outdoor laboratories” for hydrologists interested in rainfall-runoff relationships, for geochemists interested in the export of weathering products from the landscape, and for ecosystem ecologists interested in biogeochemical cycling.Research studies on small catchments have evolved from a strong focus on strictly input-output relationships (a “black-box” approach) to a focus on understanding flow paths, residence times, and biological and chemical reactions within the catchment. Tracers are essential tools for such work. In catchment studies, tracers that move with the water but do not interact with biota, soils, and rocks are sought so that water itself can be followed. Other tracers are used to follow selected biogeochemical reactions. A multitude of stable and radioactive isotopes has been used as tracers in catchment studies.

Hornberger, George M.

72

Preliminary evaluation of nominal drainage basin volume as a potentially useful morphometric parameter for small mountain basins  

SciTech Connect

Morphometric basin parameters have been used in quantitative geomorphic assessments since Horton's Hydrophysical Approach in 1945. A relationship between basin form and dominant process in small mountain basins in the western United States would be valuable for use in differentiating basins which produce deep-seated landslides from those which produce debris flows from debris slides. Drainage basin volume seems like it should be a parameter directly related to the dominant process operating in a basin. Consequently, it may be a potentially useful morphometric parameter. Nominal drainage basin volume is herein defined as the volume creates by the basin topography and linear projection of topographic contours across the basin. Incremental volume is computed from area encompassed by topographic contours and projections and the contour interval using the formula for the volume of the frustrum of a cone. Seven basins in the Wasatch Range and five in the Wasatch Plateau of Utah show strong relationship of log Basin Area to log Basin Volume (r/sup 2/ = 0.97). The relationship between average Basin Slope and log Basin Volume was poorer (r/sup 2/ = 0.78) than between Basin Slope and log Basin Area (r/sup 2/ = 0.87). This suggests that basin area may be a more useful parameter than basin volume, especially since area is more easily measured.

Keaton, J.R.

1985-01-01

73

REACH-ER: a tool to evaluate river basin remediation measures for contaminants at the catchment scale  

NASA Astrophysics Data System (ADS)

The European Union (EU) adopted the Water Framework Directive (WFD) in 2000 ensuring that all aquatic ecosystems meet ‘good status' by 2015. However, it is a major challenge for river basin managers to meet this requirement in river basins with a high population density as well as intensive agricultural and industrial activities. The EU financed AQUAREHAB project (FP7) specifically examines the ecological and economic impact of innovative rehabilitation technologies for multi-pressured degraded water bodies. For this purpose, a generic collaborative management tool ‘REACH-ER' is being developed that can be used by stakeholders, citizens and water managers to evaluate the ecological and economical effects of different remedial actions on waterbodies. The tool is built using databases from large scale models simulating the hydrological dynamics of the river basing and sub-basins, the costs of the measures and the effectiveness of the measures in terms of ecological impact. Knowledge rules are used to describe the relationships between these data in order to compute the flux concentrations or to compute the effectiveness of measures. The management tool specifically addresses nitrate pollution and pollution by organic micropollutants. Detailed models are also used to predict the effectiveness of site remedial technologies using readily available global data. Rules describing ecological impacts are derived from ecotoxicological data for (mixtures of) specific contaminants (msPAF) and ecological indices relating effects to the presence of certain contaminants. Rules describing the cost-effectiveness of measures are derived from linear programming models identifying the least-cost combination of abatement measures to satisfy multi-pollutant reduction targets and from multi-criteria analysis.

van Griensven, Ann; Haest, Pieter Jan; Broekx, Steven; Seuntjens, Piet; Campling, Paul; Ducos, Geraldine; Blaha, Ludek; Slobodnik, Jaroslav

2010-05-01

74

Spatial and temporal variations of herbicide (triazines and phenylureas) concentrations in the catchment basin of the Marne river (France).  

PubMed

Triazine and phenylurea concentrations were investigated in four sub-basins of the Marne river (France) in 1992 and 1993. The peak concentrations of atrazine, simazine and isoproturon occurred between March and July. In the four basins, the peaks were in relation with the herbicide application periods and with the important rainfalls, except for the isoproturon. The peaks of terbutryne and ametryne came later in the year, due to their use for weed control on post-emergent corn. For the phenylureas, the peak concentrations were observed in March-April next to the spraying period on winter cereals. The fast transfer of those herbicides was related to their high water solubility. In all the samples, the deethylatrazine (DEA) was detected 1 month after the atrazine due to its degradation within the soils which is of minor importance as compared to its transport by surface waters and also, to interactions between the silt sheet and the stream itself. The DAR evolution showed that the atrazine residence time depends both on the run-off in the first centimetres of the soil and on the treatment periods, particularly in the Grand Morin. The Marne river contamination level was similar to that of the Mélarchez and of the Grand Morin. The minor pollution of the Orgeval was related to minor cultivated areas. PMID:9926428

Garmouma, M; Teil, M J; Blanchard, M; Chevreuil, M

1998-12-11

75

Soil water conservation and rainwater harvesting strategies in the semi-arid Mzingwane Catchment, Limpopo Basin, Zimbabwe  

NASA Astrophysics Data System (ADS)

Various soil water management practices have been developed and promoted for the semi arid areas of Zimbabwe. These include a variety of infield crop management practices that range from primary and seconday tillage approaches for crop establishment and weed management through to land forming practices such as tied ridges and land fallowing. Tillage methods evaluated in this study include deep winter ploughing, no till tied ridges, modified tied ridges, clean and mulch ripping, and planting basins. Data collected from the various trials since the 1990s show that mulch ripping and other minimum tillage practices consistently increased soil water content and crop yields compared to traditional spring ploughing. Trial results also showed higher soil loss from conventionally ploughed plots compared to plots under different minimum tillage practices.

Mupangwa, Walter; Love, David; Twomlow, Steve

76

Detecting changes in streamflow response to changes in non-climatic catchment conditions: farm dam development in the Murray–Darling basin, Australia  

Microsoft Academic Search

Anecdotal evidence suggests that farm dams have an impact on the streamflow regime of a catchment. There is however a notable absence of suitable information on the nature and magnitude of these impacts. This work seeks to address this knowledge gap by identifying the nature of the impact of farm dams on the hydrology of catchments in the Murray–Darling Drainage

S. Yu. Schreider; A. J. Jakeman; R. A. Letcher; R. J. Nathan; B. P. Neal; S. G. Beavis

2002-01-01

77

Relative weathering intensity of calcite versus dolomite in carbonate-bearing temperate zone watersheds: Carbonate geochemistry and fluxes from catchments within the St. Lawrence and Danube river basins  

NASA Astrophysics Data System (ADS)

Calcite and dolomite solubilities in open weathering environments are proportional to pCO2 and inversely proportional to temperature, and dolomite solubility is progressively greater than calcite below 25°C. The continent-scale weathering budget reveals the significance of the Northern Hemisphere (NH) to globally integrated riverine fluxes of Ca2+, Mg2+, and HCO3-. The NH contributes 70% of the global HCO3- flux while only 54% of the riverine discharge. We present results of a comparative hydrogeochemical study of carbonate mineral equilibria and weathering fluxes in two NH carbonate-rich river basins. Surface water geochemistry and discharge were determined for headwater streams in Michigan and Slovenia within the St. Lawrence and Danube river basins. Michigan watersheds are established atop carbonate-bearing glacial drift deposits derived from erosion of Paleozoic strata with thick soil horizons (100-300 cm). Slovenia watersheds drain Mesozoic bedrock carbonates in alpine and dinaric karst environments with thin soil horizons (0-70 cm). Carbonate weathering intensity is a parameter that normalizes river runoff and HCO3- concentration to catchment area (meq HCO3- km-2 s-1), summing calcite and dolomite contributions, and is used to gauge the effects of climate, land use, and soil thickness on organic-inorganic carbon processing rates. Importantly, Michigan riverine discharge is one-tenth of Slovenian rivers, providing the opportunity to evaluate the kinetics of carbonate mineral equilibration. The study rivers are HCO3- - Ca2+ - Mg2+ waters, supersaturated for calcite at pCO2 values in excess of the atmosphere. As discharge varies, HCO3- concentrations differ by less than 20% for any location, and Mg2+/Ca2+ remains relatively fixed for Michigan (0.5) and Slovenia streams (0.4), requiring that dolomite dissolution exceed calcite on a mole basis. The ability of calcite and dolomite dissolution to keep pace with increased discharge indicates carbonate weathering is limited only by water flux and temperature-dependent solubility in these watersheds. Carbonate weathering intensity in Michigan and Slovenia exceeds the world average by factors between 2 and 20, and dolomite weathering intensity, estimated from riverine Mg2+ fluxes, exceeds the world average by factors between 2 and 15. Thus global fluxes of carbonate-related weathering products appear heavily skewed toward carbonate-bearing environments at higher latitudes with relatively low mean annual temperatures and high discharge.

Szramek, Kathryn; McIntosh, Jennifer C.; Williams, Erika L.; Kanduc, Tjasa; Ogrinc, Nives; Walter, Lynn M.

2007-04-01

78

The effects of soil properties on the turbidity of catchment soils from the Yongdam dam basin in Korea.  

PubMed

Environmental concerns have been raised that suspended solids in turbid water adversely affect human health, and that their removal increases in the cost of water treatment. The Yongdam dam reservoir, located in the southwestern region of Korea, is severely affected by inflowing turbid water after storms. In this study, soil samples were collected from 37 sites in the Yongdam upstream basin to investigate mineralogical and environmental factors associated with the turbidity potential of soils in water environments. Turbidity potential was estimated by measuring the turbidity of soil-suspension solutions after settling for 24 h. The mineralogy of the soils was dominated by four minerals-quartz, microcline, albite, and muscovite-with lesser amounts of hornblende, chlorite, kaolinite, illite, and mixed layer illite. The quartz content was the most variable of the soil mineralogy among the collected samples. Principal-components analysis (PCA) was used to examine relationships between turbidity potential and other soil properties. The variables considered in the PCA included turbidity potential, quartz content, albite content, mean size of soil particles, clay content, clay mineral content, zeta potential, conductivity, and pH of the soil-suspension solution. The first two components of the PCA explained 52% of the overall variation of the selected variables. The first component was possibly explained by physical properties such as the size of the soil particles; the second was correlated with chemical properties of the soils, for example dissolution and extent of weathering. Closer examination of the PCA results revealed that the quartz content of the soils was negatively correlated with their turbidity potential. A linear correlation (r = 0.63) was obtained between measured turbidity potential and that predicted using multiple regression analysis based on the content of clay-sized particles, clay minerals, and quartz, and the conductivity of the soil-suspension solution. PMID:18473181

Hur, Jin; Jung, Myung Chae

2008-05-13

79

Large-scale single incised valley from a small catchment basin on the western Adriatic margin (central Mediterranean Sea)  

NASA Astrophysics Data System (ADS)

The Manfredonia Incised Valley (MIV) is a huge erosional feature buried below the Apulian shelf, on the western side of the Adriatic margin. The incision extends more than 60 km eastward, from the Tavoliere Plain to the outer shelf, not reaching the shelf edge. High-resolution chirp sonar profiles allow reconstruction of the morphology of the incision and its correlation at regional scale. The MIV records a single episode of incision, induced by the last glacial-interglacial sea level fall that forced the rivers draining the Tavoliere Plain to advance basinward, reaching their maximum extent at the peak of the Last Glacial Maximum. The valley was filled during a relatively short interval of about 10,000 yr during the Late Pleistocene-Holocene sea level rise and almost leveled-off at the time of maximum marine ingression, possibly recording the short-term climatic fluctuations that occurred. The accommodation space generated by the lowstand incision was exploited during the following interval of sea level rise by very high rates of sediment supply that allowed the preservation of up to 45 m of valley fill. High-resolution chirp sonar profiles highlight stratal geometries that are consistent with a typical transgressive valley fill of an estuary environment, including bay-head deltas, central basin and distal barrier-island deposits, organized in a backstepping configuration. The highest complexity of the valley fill is reached in the shallowest and most proximal area, where a kilometric prograding wedge formed during a period dominated by riverine input, possibly connected to high precipitation rates. Based on the depth of the valley margins during this interval, the fill was likely isochronous with the formation of sapropel S1 in the Mediterranean region and may have recorded significant fluctuations within the hydrological cycle.

Maselli, Vittorio; Trincardi, Fabio

2013-01-01

80

Preliminary report on coal pile, coal pile runoff basins, and ash basins at the Savannah River Site: effects on groundwater.  

National Technical Information Service (NTIS)

Coal storage piles, their associated coal pile runoff basins and ash basins could potentially have adverse environmental impacts, especially on groundwater. This report presents and summarizes SRS groundwater and soil data that have been compiled. Also, a...

E. Palmer

1997-01-01

81

Preliminary study on rapid bioassessment with benthic macroinvertebrates in the headwater streams of the Loei River and adjacent catchments, Thailand.  

NASA Astrophysics Data System (ADS)

Thailand currently lacks formal bioassessment approaches and protocols to assist management decisions for water quality. This study aims to develop recommendations for (1) a professional level of rapid bioassessment by using benthic macroinvertebrate assemblages for streams in Thailand and (2) an appropriate technique for the volunteer monitoring groups. Eleven physico-chemical parameters were measured at each of seven reference sites and eight test sites in the Loei River and adjacent areas. The biological research methods were designed around the USEPA Rapid Bioassessment Protocols using the multi-habitat approach. Four fixed count subsamplings (100, 200, 300 and 500) were randomly removed using a standardized gridded pan to evaluate an appropriate level for bioassessment in Thailand streams. The preliminary results revealed that the test sites had BOD5 and Chorophyll a significantly higher than those reference sites. Two hundred organisms counted are adequate for bioassessment purposes. The differences between multimetric and multivariate analyses were examined.

Boonsoong, B.; Sangpradub, N.; Barbour, M. T.

2005-05-01

82

Inferring the effect of catchment complexity on mesoscale hydrologic response  

NASA Astrophysics Data System (ADS)

The effect of catchment complexity on hydrologic and hydrochemical catchment response was characterized in the mesoscale Dill catchment (692 km2), Germany. This analysis was developed using multivariate daily stream concentration and discharge data at the basin outlet, in connection with less frequently sampled catchment-wide end-member chemistries. The link between catchment-wide runoff sources and basin output was observed through a combination of concentration-discharge (C-Q) analysis and multivariate end-member projection. Subsurface stormflow, various groundwater and wastewater sources, as well as urban surface runoff emerged in catchment output chemistry. Despite the identification of multiple sources, several runoff sources observed within the catchment failed to display consistent links with the output chemistry. This failure to associate known source chemistry with outlet chemistry may have resulted from a lack of hydraulic connectivity between sources and basin outlet, from different arrival times of subbasin-scale runoff contributions, and also from an overlap of source chemistries that subsumed discrete runoff sources in catchment output. This combination of catchment heterogeneity and complexity simply suggests that the internal spatial organization of the catchment impeded the application of lumped mixing calculations at the 692 km2 outlet. Given these challenges, we suggest that in mesoscale catchment research, the potential effects of spatial organization should be included in any interpretation of highly integrated response signals, or when using those signals to evaluate numerical rainfall-runoff models.

FröHlich, Holger L.; Breuer, Lutz; Vaché, Kellie B.; Frede, Hans-Georg

2008-09-01

83

A preliminary assessment of the spatial sources of contemporary suspended sediment in the Ohio River basin, United States, using water quality data from the NASQAN programme in a source tracing procedure  

USGS Publications Warehouse

Reliable information on catchment scale suspended sediment sources is required to inform the design of management strategies for helping abate the numerous environmental issues associated with enhanced sediment mobilization and off-site loadings. Since sediment fingerprinting techniques avoid many of the logistical constraints associated with using more traditional indirect measurement methods at catchment scale, such approaches have been increasingly reported in the international literature and typically use data sets collected specifically for sediment source apportionment purposes. There remains scope for investigating the potential for using geochemical data sets assembled by routine monitoring programmes to fingerprint sediment provenance. In the United States, routine water quality samples are collected as part of the US Geological Survey's revised National Stream Quality Accounting Network programme. Accordingly, the geochemistry data generated from these samples over a 10-year period (1996-2006) were used as the basis for a fingerprinting exercise to assess the key tributary sub-catchment spatial sources of contemporary suspended sediment transported by the Ohio River. Uncertainty associated with the spatial source estimates was quantified using a Monte Carlo approach in conjunction with mass balance modelling. Relative frequency weighted means were used as an alternative way of summarizing the spatial source contributions, thereby avoiding the need to use confidence limits. The results should be interpreted in the context of the routine, but infrequent nature, of the suspended sediment samples used to assemble geochemistry as a basis for the sourcing exercise. Nonetheless, the study demonstrates how routine monitoring samples can be used to provide some preliminary information on sediment provenance in large drainage basins. ?? 2011 John Wiley & Sons, Ltd.

Zhang, Y. S.; Collins, A. L.; Horowitz, A. J.

2012-01-01

84

Variations of temperature and hydrologic regimes of the region of Ladoga Lake catchment basin in the 20th and 21st centuries according to data of modern climate models  

NASA Astrophysics Data System (ADS)

In the region of the Ladoga Lake catchment basin, we perform data analysis on a set of different modern climate models with different Intergovernmental Panel on Climate Change (IPCC) scenarios in the 20th and 21st centuries; this set includes global models such as ECHAM4/OPYC3 (Max Planck Institute for Meteorology, Germany), HadCM3 (Hadley Centre Coupled Model, England), and RCAO (Rossby Centre Regional Atmosphere-Ocean) models. Two variants of the boundary conditions for these climate models (Rossby Center of Swedish Meteorological and Hydrological Institute, SMHI) are used. We present the results of a diagnosis of the model-predicted near-surface temperature (T), precipitation (P), evaporation (E), and water budget (P-E) in the Ladoga Lake catchment based on their comparison with empirical data in twentieth century. We obtain scenario estimates of the variations of temperature and hydrologic regimes of Ladoga Lake catchment when IPCC IS92a, A2, and B2 scenarios are fulfilled, describing the prognostic growth of anthropogenic emissions of greenhouse gases and aerosol to the atmosphere, and discuss the recommendations for their use.

Rumyantsev, V. A.; Efimova, L. K.; Golitsyn, G. S.; Khon, V. Ch.

2010-02-01

85

TOC fluctuations in a humic lake as related to catchment acidification, season and climate  

Microsoft Academic Search

Studies of fluctuations in total organic carbon (TOC) were performedin both the reference basin and the acidified basin of experimental LakeSkjervatjern, in order to separate effects of various catchment and in-lakeprocesses. Nearly five years of catchment acidification did not inducesignificant changes in TOC. TOC concentrations was not related clearly toprecipitation or runoff. In both basins, there was a regular, seasonal

Dag O. Hessen; Egil T. Gjessing; Johan Knulst; Eirik Fjeld

1997-01-01

86

Preliminary seismicity and focal mechanisms for the Southern Great Basin of Nevada and California, January 1992 - September 1992  

NASA Astrophysics Data System (ADS)

The telemetered southern Great Basin seismic network (SGBSN) is operated for the Department of Energy's Yucca Mountain Project (YMP). The US Geological Survey, Branch of Earthquake and Landslide Hazards, maintained this network until September 30, 1992, at which time all operational and analysis responsibilities were transferred to the University of Nevada at Reno Seismological Laboratory (UNRSL). This report contains preliminary earthquake and chemical explosion hypocenter listings and preliminary earthquake focal mechanism solutions for USGS/SGBSN data for the period January 1, 1992 through September 30, 1992, 15:00 UTC.

Harmsen, S. C.

87

Preliminary seismicity and focal mechanisms for the southern Great Basin of Nevada and California: January 1992 through September 1992  

SciTech Connect

The telemetered southern Great Basin seismic network (SGBSN) is operated for the Department of Energy`s Yucca Mountain Project (YMP). The US Geological Survey, Branch of Earthquake and Landslide Hazards, maintained this network until September 30, 1992, at which time all operational and analysis responsibilities were transferred to the University of Nevada at Reno Seismological Laboratory (UNRSL). This report contains preliminary earthquake and chemical explosion hypocenter listings and preliminary earthquake focal mechanism solutions for USGS/SGBSN data for the period January 1, 1992 through September 30, 1992, 15:00 UTC.

Harmsen, S.C.

1994-06-01

88

Las Vegas Basin Seismic Response Project: Preliminary Results From Seismic Refraction Experiments, Las Vegas, NV  

Microsoft Academic Search

In May and September 2002, seismic refraction data were acquired in the Las Vegas basin. Located in the southern Basin and Range province, the cities of Las Vegas, North Las Vegas, and Henderson sit atop a fault-bounded basin with a depth of up to 5 km and basin dimensions of roughly 60 km wide (east-west) by 50 km in length

S. A. Zaragoza; C. M. Snelson; S. H. Harder; G. Kaip; B. Luke; B. J. Buck; A. D. Hanson

2002-01-01

89

Lunar Orientale Basin Mineralogy as Viewed by Chandrayaan-1: Preliminary Results  

Microsoft Academic Search

The Orientale basin is the youngest and most well-preserved large basin on the Moon. Thus, analysis of Orientale permits us to assess: 1) the primary structure of fresh basin interiors including the nature and distribution of impact melts, and 2) the nature of the early stages of filling of basins with mare basalts. We have undertaken a joint analysis of

James W. Head; C. M. Pieters; J. Boardman; B. Buratti; R. Clark; J. Combe; R. Green; J. N. Goswami; M. Hicks; P. Isaacson; R. Klima; G. Kramer; S. Kumar; K. Kumar; S. Lundeen; E. Malaret; T. B. McCord; J. Mustard; J. Nettles; N. Petro; C. Runyon; M. Staid; J. Sunshine; L. Taylor; S. Tompkins; P. Varanasi

2009-01-01

90

Preliminary Tectonic Subsidence Results: Outer Shelf and Upper Slope Sites, Canterbury Basin from IODP Expedition 317  

NASA Astrophysics Data System (ADS)

Integrated Ocean Drilling Program (IODP) Expedition 317 drilled four sites, generating a transect from the shelf to the upper slope of the Canterbury Basin, South Island, New Zealand. One of the primary goals of the expedition was to determine the magnitude and timing of sea level change using backstripping analysis. Integration of moisture and density (MAD) data, smear slide data, lithologic descriptions, carbonate analyses, age estimates and benthic foraminiferal estimates of water depths from shipboard results provides a preliminary database for backstripping Site U1351 on the mid to outer shelf and Site U1352 on the upper slope. These boreholes penetrated to about 10 Ma and 35 Ma, respectively. In these preliminary analyses, older sediment thicknesses, ages and water depths were taken from the nearby industry Clipper-1 well. In the absence of water depth corrections, the two IODP sites and the Clipper-1 well show an increase in subsidence rate beginning 15 to 8 Ma and continuing to the present. The water depths observed in Clipper-1 shoal slightly through this time, reducing the magnitude of the subsidence event. Tectonics seem to have been more active at the two IODP sites. Both show significant tectonic uplift of at least 300 to 400 meters between about 6.5 and 4.5 Ma, after which, they follow the general, trend of rapid subsidence observed at the Clipper-1 well. Additionally, our oldest dataset (Site U1352) shows a large tectonic uplift event of at least 2000 m that occurred between 17.5 and 11 Ma. Higher frequency variations are superimposed on the long-term trends at both IODP sites. These fluctuations are most likely due to glacioeustasy. The magnitudes of these events are higher than those observed through other proxies. It is likely that data refinement in onshore studies will be able to resolve this issue.

Kominz, M. A.; Expedition 317 Shipboard Scientific Party

2010-12-01

91

Human impact variability on soil erosion during the Holocene based on valley floor sediments study in a Parisian basin fluvial catchment (France): crossing sedimentological, archaeological and palynological proxies  

Microsoft Academic Search

This work is part of the French CNRS ECLIPSE program « Impact anthropique sur l'érosion des sols et la sédimentation dans les zones humides associées durant l'Holocène ». It aims to reconstitute the evolution of human impact on soil erosion at various periods via the study of Holocene sedimentary archives. In this framework the Choisille catchment (288 km²; elevation: 50

E. Morin; A. L. Cyprien; I. Gay-Ovejero; F. Hinschberger; C. Joly; J. J. Macaire; N. Poirier; L. Visset; E. Zadora-Rio

2009-01-01

92

Managing the impact of gold panning activities within the context of integrated water resources management planning in the Lower Manyame SubCatchment, Zambezi Basin, Zimbabwe  

Microsoft Academic Search

Riverbed alluvial gold panning activities are a cause for degradation of river channels and banks as well as water resources, particularly through accelerated erosion and siltation, in many areas of Zimbabwe. The lower Manyame sub-catchment located in the Northern part of the country is one such area. This study analysed the implications of cross-sectoral coordination of the management of panning

Nonhlanhla Zwane; David Love; Zvikomborero Hoko; Dennis Shoko

2006-01-01

93

Analysis of suspended sediment transport in a mesoscale catchment in northern Mongolia  

NASA Astrophysics Data System (ADS)

The input of fine sediments has an important impact on the ecological status of rivers. In case of the investigated 15.000km2 Kharaa catchment in Mongolia it is assumed to be the main source for pollutants and nutrients. The identification of the sediment sources and the quantification of sediment transport are therefore important for river management measures, especially in semi-arid Mongolia where massive climate and land use changes are expected. Since data scarcity is a central problem in the investigated area a monitoring scheme has been developed, providing continuous data on discharge, turbidity and temperature at selected sites. In this study two different models are tested to describe sediment transport on a mesoscale. The semi distributed, conceptual hydrological and nutrient transport model HYPE is used to model the runoff in the catchment. The model has been development based on the HBV-model that allows the use of coupled sub basins. Secondly a regional catchment scale sediment budget model (SedNet) is employed to calculate the sediment budget. This model uses a DEM, land use- and soil maps and climate data and is taking into account also hill slope, gully- and riverbank erosion. Sediment source fingerprinting is used to identify and localize the most important sediment sources in the catchment. Geochemical tracer techniques for spatial source identification, using major elements (e.g. Si, Al, Mg, Fe, Na, K, P) and trace elements (e.g. Ba, Pb, Sr, Zn) are applied. Samples from the river junctions of the outlet of each sub basin into the main tributary were taken and the fine sediment fraction (<10?m) has been analysed. The contribution of each sub basin of the suspended sediment in the main tributary has been assessed with the help of a mixing model. Further sampling has been conducted on a selection of topsoil eroding surface reference sites and on stream banks, in order to gain information about the importance and proportions of surface-, stream bank and gully erosion in the catchment. These samples are used for an isotope fingerprinting using the atmospheric fallout radionuclides 137Cs, 210Pb and 7Be. Preliminary results suggest that only a small part of the catchment contributes considerably to total sediment load. The coupling of the catchment model with an in stream River Water Quality model in the future will lead to a better understanding of the influencing factors on the aquatic ecosystems in the Kharaa River and allow the analysis of land use and climate change scenarios.

Theuring, Philipp; Rode, Michael

2010-05-01

94

Resource appraisal and preliminary planning for surface mining of oil shale Piceance Creek Basin, Colorado  

Microsoft Academic Search

Methods used in the computerized resource mapping of the Piceance Creek Basin are discussed. Study of seven succeeding oil shale zones shows that the thickest and richest oil shale deposits in the Piceance Creek Basin occur in the central portions of the northern half of the basin. Information on resource recovery, environmental impacts, technical mining limitations, and cost was gathered

C. E. Banks; B. C. Franciscotti

1976-01-01

95

Preliminary Measurements Of N2O Partial Pressures In Rivers of Amazon Basin, Brazil  

NASA Astrophysics Data System (ADS)

The concentrations of nitrous oxide (N2O), an important component of the greenhouse effect and with a long residence time in the atmosphere, have significantly increased in this century. The reasons for this atmospheric increase in N2O are still partially unexplained. This uncertainty is worse in relation to aquatic environments. Here we report on preliminary measurements of N2O partial pressures in rivers of the Amazon basin. The study areas are in the state of Rondonia (rivers Ji Parana, Urupa, Comemoracao and Pimenta Bueno) and Amazonas (rivers Solimoes and Negro). The rivers were sampled from October 2005 to April 2006, using with immersion pumps, lowered in the middle of the channel to 60% of total depth. Water was pumped directly into a 1 l plastic bottle, which was overflown three times before closing. Using syringes, 60 ml of N2 were injected into the bottle, simultaenously to the withdrawn of 60 ml of sample. N2O was extracted into these 60 ml of N2 by shaking vigorously for 2 minutes. With the same syringes, the gas was taken from the bottles and injected into sealed evacuated 25 ml vials. Atmospheric samples were taken from one meter above the water column and stored the same way. N2O partial pressures were determined on a Shimadzu GC-14 Green House Gas Analyzer. All rivers showed little variations in N2O partial pressures. Average values in the rivers of Rondonia were around 0.41 ± 0.07 ? atm (n=46), whereas the Solimoes and Negro rivers, in the state of Amazonas, showed values around 0.43 ± 0.08 ? atm (n=131). Atmospheric averages were approximately 0.34 ± 0.04 ? atm (n=58) and 0.32 ± 0.03 ? atm (n=134) in the states of Rondonia and Amazonas, respectively. This means that, although these waters are supersatured in CO2, making evasive fluxes of this gas an important component of the C cycle in this basin, the same does not occur in the N cycle. Small differences in partial pressures of N2O between water and air will result in small fluxes of this gas to the atmosphere from the middle of the river channels. However, at the river margins and riparian zones, significantly different redox conditions may occur, which should be further investigated to fully understand the role of N2O fluxes in these riverine systems.

Oliveira, C. B.; Rasera, M. F.; Krusche, A. V.; Victoria, R. L.; Richey, J. E.; Cunha, H. B.; Gomes, B. M.

2006-12-01

96

Space-time observations in nested catchment experiments of representative basins—experiences gained and lessons learned to help the PUB initiative in the World's biomes  

Microsoft Academic Search

Field experiences with a Nested Catchment Experiment (NCE) layout sited in a biome of a developing country are outlined in terms of both space-time observational hydrology and modelling constraints. This NCE encompasses scales of 0.125 km2, 1.1 km2, 19.9 km2, 165 km2 and 560 km2, aided by experimental plots of 1 m2 under different land uses. To address the prediction

E. M. MENDIONDO; C. E. TUCCI; R. T. CLARKE; N. M. CASTRO; J. GOLDENFUM; P. CHEVALLIER

97

Preliminary paleomagnetic results from Miocene Monterey Formation, Shell Beach, Pismo Basin, central California  

SciTech Connect

An excellently exposed 300-m thick section of the Monterey Formation at Shell Beach, Pismo basin, has been sampled at intervals of 2-5 m for paleomagnetic analysis. This study is part of an ongoing research aimed at providing detailed magnetostratigraphy and geochronology of the Monterey Formation sections from northern and central California. Here they report on the detailed magnetostratigraphy and diatom biostratigraphy of the upper 150 m of the Shell Beach section, which spans a 2-m.y. long interval in the upper middle Miocene (upper lower Mohnian). Their preliminary data reveal two distinct components of magnetization in about 75% of the dolomite samples and 40-60% of the samples from calcareous to siliceous shales and cherty porcelanitic rocks. The first of these components (a), which is removed at T less than or equal to 200/sup 0/C, is presumably recent viscous magnetization. The thermally discrete second component (b) had dual polarity and stable and consistent directions with a relatively narrow unblocking temperature range (200/sup 0/-400/sup 0/C). Usually this component remains blocked on heating to 450/sup 0/-500/sup 0/C and is then masked by unusually high intensity components of magnetochemical origin produced during heating in the lab. In their best samples, orthogonal vector diagrams show that b is the early characteristic remanence, and all evidence to date suggests that this component is pre-Pliocene-Pleistocene folding and most likely primary. By using diatom data extracted from their samples, they are attempting to obtain detailed magnetostratigraphy for this section of the Monterey Formation.

Khan, S.M.; Coe, R.S.; Barron, J.A.

1988-03-01

98

Management of Dams in TransNational River Basins — a Preliminary Sustainability Impact Assessment for the Upper Elbe River Basin  

Microsoft Academic Search

Dams or systems of dams can significantly change the properties of river basins, such as flow, retention or the management\\u000a of the water resources in general. Furthermore, dams and their management are known to show relevant impacts on the environment,\\u000a economic activities and social structures in their very neighbourhood, upstream and downstream. Taking into consideration\\u000a that nowadays numerous dams in

Martin Socher; Stefan Dornack; Hans Ulrich Sieber

99

Managing waterway health in the Goulburn Broken Catchment, Victoria, Australia.  

PubMed

Historically within most catchments, resource management programs have been planned and implemented in isolation of one another. This was once the case in the Goulburn Broken Catchment, a major catchment of the Murray Darling Basin, Australia. Although only 2% of the Murray Darling Basin's land area, the catchment generates 11% of the basin's water resources. Learning from the past, a cooperative and collaborative approach to natural resource programs has developed. This approach is the envy of many other catchment communities and agencies. Through a combination of "Partnership Programs", "Operational Initiatives" and community involvement, significant programs have been implemented within the catchment, which will benefit not only the local community but communities further afield. The outcomes of the waterway health program highlight the benefits provided through the establishment of cooperative and partnership resource improvement programs. These programs were founded on the ability of the community to recognise the need for integration, base management decisions on best available science and an ability to work together. Their effective delivery has been provided through the resources provided, to the local community, by the Natural Heritage Trust with matching and State and local allocations. While programs have shown success, challenges still face the community. These challenges include verification and implementation of environmental flows, storage of the catchment's vital water resources, and maintaining community involvement and participation in on-going works programs. The Goulburn Broken Catchment community, with the support of Federal, State and Local Governments, is looking at opportunities for continued improvements in waterway health. PMID:11419136

Tennant, W; Sheed, J

2001-01-01

100

Hydrologic comparison between a lowland catchment (Kielstau, Germany) and a mountainous catchment (XitaoXi, China) using KIDS model in PCRaster  

NASA Astrophysics Data System (ADS)

The KIDS model (Kielstau Discharge Simulation model) is a simple rainfall-runoff model developed originally for the Kielstau catchment. To extend its range of application we applied it to a completely different catchment, the XitaoXi catchment in China. Kielstau is a small (51 km2) lowland basin in Northern Germany, with large proportion of wetland area. And XitaoXi is a mesoscale (2271 km2) mountainous basin in the south of China. Both catchments differ greatly in size, topography, landuse, soil properties, and weather conditions. We compared two catchments in these features and stress on the analysis how the specific catchment characteristics could guide the adaptation of KIDS model and the parameter estimation for streamflow simulation. The Nash and Sutcliffe coefficient was 0.73 for Kielstau and 0.65 for XitaoXi. The results suggest that the application of KIDS model may require adjustments according to the specific physical background of the study basin.

Zhang, X.; Hörmann, G.; Fohrer, N.

2009-08-01

101

Characterizing chromophoric dissolved organic matter in Lake Tianmuhu and its catchment basin using excitation-emission matrix fluorescence and parallel factor analysis.  

PubMed

Chromophoric dissolved organic matter (CDOM) is an important optically active substance that transports nutrients, heavy metals, and other pollutants from terrestrial to aquatic systems and is used as a measure of water quality. To investigate how the source and composition of CDOM changes in both space and time, we used chemical, spectroscopic, and fluorescence analyses to characterize CDOM in Lake Tianmuhu (a drinking water source) and its catchment in China. Parallel factor analysis (PARAFAC) identified three individual fluorophore moieties that were attributed to humic-like and protein-like materials in 224 water samples collected between December 2008 and September 2009. The upstream rivers contained significantly higher concentrations of CDOM than did the lake water (a(350) of 4.27±2.51 and 2.32±0.59 m(-1), respectively), indicating that the rivers carried a substantial load of organic matter to the lake. Of the three main rivers that flow into Lake Tianmuhu, the Pingqiao River brought in the most CDOM from the catchment to the lake. CDOM absorption and the microbial and terrestrial humic-like components, but not the protein-like component, were significantly higher in the wet season than in other seasons, indicating that the frequency of rainfall and runoff could significantly impact the quantity and quality of CDOM collected from the catchment. The different relationships between the maximum fluorescence intensities of the three PARAFAC components, CDOM absorption, and chemical oxygen demand (COD) concentration in riverine and lake water indicated the difference in the composition of CDOM between Lake Tianmuhu and the rivers that feed it. This study demonstrates the utility of combining excitation-emission matrix fluorescence and PARAFAC to study CDOM dynamics in inland waters. PMID:21840562

Zhang, Yunlin; Yin, Yan; Feng, Longqing; Zhu, Guangwei; Shi, Zhiqiang; Liu, Xiaohan; Zhang, Yuanzhi

2011-07-28

102

Implications for Fault and Basin Geometry in the Central California Coast Ranges from Preliminary Gravity and Magnetic Data  

NASA Astrophysics Data System (ADS)

Preliminary aeromagnetic and newly processed gravity data help define block-bounding faults and deep sedimentary basins in the central California Coast Ranges, ranging from the Hosgri fault east to the San Andreas fault and from Monterey Bay south to Pt. Conception. Interpretation of these data results in an improved framework for seismic hazard and groundwater studies. Aeromagnetic data include a new survey with a flight-line spacing of 800 m at a nominal 300 m above ground and covering 15,000 km2. More than 11,500 gravity measurements, reprocessed with terrain corrections calculated from 30-m DEMs, form a roughly 2-km grid over most of the study area. Combined potential-field data and existing geologic mapping, delineate major fault-bounded blocks in the central California Coast Ranges. Main block-bounding faults from west to east include the San Gregorio- Hosgri, San Luis-Willmar-Santa Maria River-Little Pine, Oceanic-West Huasna, Nacimiento, Rinconada-South Cuyama, San Juan-Chimineas-Morales, and San Andreas faults. Most of these faults have evidence of Quaternary activity. Gravity gradients indicate that the reach of the San Andreas fault bounding the Gabilan Range and the northern extension of the Rinconada fault bounding the Santa Lucia Range dip steeply southwestward and have a reverse component of slip. Magnetic and microseismicity data suggest that the northern reach of the Hosgri fault dips eastward. The potential-field data also delineate several deep sedimentary basins, such as the 3-4 km deep Cuyama basin, the Santa Maria basin, and several basins along and possibly offset by the Rinconada fault. Gravity data show that the main west-northwest-striking faults bounding the Cuyama basin dip away from the basin, indicating compression adjacent to the big bend in the San Andreas fault. Prominent gravity and magnetic highs northeast of the San Andreas fault immediately east of Cuyama Valley suggest that there the San Andreas fault dips southwest. Such dip information is important for estimating shaking potential of scenario earthquakes and for calculating geodetic deformation whereas basin shapes and fault locations are critical components for groundwater flow modeling.

Langenheim, V. E.; Jachens, R. C.; Graymer, R. W.; Wentworth, C. M.

2008-12-01

103

Effect of initial conditions of a catchment on seasonal streamflow prediction using ensemble streamflow prediction (ESP) technique for the Rangitata and Waitaki River basins on the South Island of New Zealand  

NASA Astrophysics Data System (ADS)

Increased access to water is a key pillar of the New Zealand government plan for economic growths. Variable climatic conditions coupled with market drivers and increased demand on water resource result in critical decision made by water managers based on climate and streamflow forecast. Because many of these decisions have serious economic implications, accurate forecast of climate and streamflow are of paramount importance (eg irrigated agriculture and electricity generation). New Zealand currently does not have a centralized, comprehensive, and state-of-the-art system in place for providing operational seasonal to interannual streamflow forecasts to guide water resources management decisions. As a pilot effort, we implement and evaluate an experimental ensemble streamflow forecasting system for the Waitaki and Rangitata River basins on New Zealand's South Island using a hydrologic simulation model (TopNet) and the familiar ensemble streamflow prediction (ESP) paradigm for estimating forecast uncertainty. To provide a comprehensive database for evaluation of the forecasting system, first a set of retrospective model states simulated by the hydrologic model on the first day of each month were archived from 1972-2009. Then, using the hydrologic simulation model, each of these historical model states was paired with the retrospective temperature and precipitation time series from each historical water year to create a database of retrospective hindcasts. Using the resulting database, the relative importance of initial state variables (such as soil moisture and snowpack) as fundamental drivers of uncertainties in forecasts were evaluated for different seasons and lead times. The analysis indicate that the sensitivity of flow forecast to initial condition uncertainty is depend on the hydrological regime and season of forecast. However initial conditions do not have a large impact on seasonal flow uncertainties for snow dominated catchments. Further analysis indicates that this result is valid when the hindcast database is conditioned by ENSO classification. As a result hydrological forecasts based on ESP technique, where present initial conditions with histological forcing data are used may be plausible for New Zealand catchments.

Singh, Shailesh Kumar; Zammit, Christian; Hreinsson, Einar; Woods, Ross; Clark, Martyn; Hamlet, Alan

2013-04-01

104

78 FR 16495 - Basin Farm Renewables, LLC; Notice of Preliminary Permit Application Accepted for Filing and...  

Federal Register 2010, 2011, 2012, 2013

...kilowatts; (4) a 2,800-foot- long, 15-kilovolt buried transmission line connected to the existing electrical distribution system at Basin Farm; and (5) appurtenant facilities. The proposed project would [[Page 16496

2013-03-15

105

Modeling sediment yields in Italian catchments  

NASA Astrophysics Data System (ADS)

Sediment yield observations, derived from 40 long-term sedimentation records in Italian reservoirs, were used to calibrate and validate the spatially distributed sediment delivery model WaTEM/SEDEM using the best data available at national scale. The sediment yield data set includes records from semi-natural catchments in northern Italy as well as agricultural and semi-natural basins in central and southern Italy. The average size of the catchments is 150 km2 with mean annual sediment yields ranging from 0.20 to 20 t ha-1 year-1. WaTEM/SEDEM estimates mean annual sediment fluxes to permanent river channels. Depending on the local transport capacity, the sediment flux is detachment-limited or transport-limited. The optimal transport capacity parameters for Italian conditions were derived via automatic calibration procedures. A global model calibration procedure taking into account all catchments in the dataset led to an overestimation of the sediment yield for the mountain catchments and an underestimation for the non-mountain catchments. Sediment yield estimates are more reliable when calibration procedures are applied separately for mountain and non-mountain catchments. The model performance of WaTEM/SEDEM is rather poor in the mountain catchments (R=0.25), which suggests that the model structure is too simplified to come to an adequate description of the sediment fluxes. The model performance for the non-mountain catchments, which are more important from a management point of view, is significantly better (R=0.51). Considering the fact that data layers with a 75×75 m resolution were used, the results are encouraging the further development and application of spatially distributed sediment yield models at regional and national scale levels.

Rompaey, Anton Van; Bazzoffi, Paolo; Jones, Robert J. A.; Montanarella, Luca

2005-02-01

106

Sulfur in submarine eruptions: Observations and preliminary data from West Mata, NE Lau Basin  

NASA Astrophysics Data System (ADS)

Sulfur in its various oxidation states is a major component of magmatic volatiles; its abundance and isotopic composition constrain degassing processes as well as sulfur sources, and have been used as a tool to study sulfur cycling at convergent plate margins. However, there are almost no sulfur isotope data on active submarine eruptions as such eruptions have only been witnessed in recent years. Little is known on the effect of water depth and eruptive processes on the isotopic composition of all sulfur-bearing phases, in particular on the relationship between ?33S and ?34S. Therefore, the active eruption observed at West Mata Volcano during a NOAA/NSF rapid response cruise to the NE Lau Basin in May 2009 provided a unique opportunity to study lavas, fluids and native sulfur from an ongoing submarine eruption. West Mata is situated about 40 km west of the northern termination of the Tonga Arc and its summit is at a water depth of 1193 m. Two main areas of active vents were discovered near the summit, named Hades and Prometheus. The observed eruptive processes consisted of pyroclastic activity and degassing at both vents; additionally, extrusion of tubular pillows was observed at Hades. The eruption plumes had a pronounced yellow color, due to the presence of large quantities of native sulfur globules. Five ROV Jason 2 dives on and around the summit area returned samples of pillows, sheet flows, spatter fragments, pyroclastic deposits, as well as gas and fluid samples. The pyroclastic deposits close to the vents contain numerous sulfur droplets, whereas sediment scoops taken further from the vents are free of native sulfur, suggesting that the droplets disintegrate and dissolve over time, so their presence may be a qualitative age indicator for the eruptive material. The sulfur globules are generally quasi perfect spheres up to 5 mm in diameter, mostly yellow, but sometimes pink, orange or grey. Several droplets were found to have elongated or twisted shapes, indicating that they may have been still molten whilst being entrained in the eruption plume. Additionally, some of the pillow samples featured native sulfur trapped in the vesicles. The glasses, inferred to be derived from boninitic parent melts, appear to have lost most of their volatiles, and typically contain between 20 and 60 ppm S; preliminary data indicate that olivine-hosted melt inclusions may contain an order of magnitude more S. The fresh glasses have ?34SV-CDT values between -0.2 and 2 ‰, overlapping mantle values (0 ‰) and the low end of the range for arc volanoes (0-10 ‰). Native sulfur globules have ?34S between -2 and -3 ‰. Similar pyroclastic material containing sulfur globules has been found at NW-Rota-1, an active submarine volcano in the Mariana Trough. Sulfur globules sampled with ROV Hyperdolphin in February 2009 have values around -4 ‰. In all cases, 33S was determined to behave mass-dependently, with ?33S ( = ?33S - 0.515*?34S) values of 0.

Keller, N. S.; Rubin, K. H.; Clague, D. A.; Michael, P. J.; Resing, J. A.; Cooper, L. B.; Shaw, A. M.; Ono, S.; Tamura, Y.

2009-12-01

107

Runoff Responses to Forest Thinning at Plot and Catchment Scales in a Headwater Catchment Draining Japanese Cypress Forest  

EPA Science Inventory

We examined the effect of forest thinning on runoff generation at plot and catchment scales in headwater basins draining a Japanese cypress (Chamaecyparis obtusa) forest. We removed 58.3% of the stems (corresponding to 43.2% of the basal area) in the treated headwater basin (catc...

108

Preliminary Assessment of the Social, Economic and Environmental Impacts of Water Hyacinth in the Lake Victoria Basin and the Status of Control  

Microsoft Academic Search

The paper presents preliminary data collected in an assessment of the social, economic and environmental impacts of water hyacinth in the Lake Victoria Basin. A summary of the status of control and strategies for the future is given. The report draws on field observations made, studies through interviews of affected communities and organisations, personal communications and published reports by scientists

A. M. Mailu

109

Hydrological process representation at the meso-scale: the potential of a distributed, conceptual catchment model  

Microsoft Academic Search

In order to achieve a process-oriented simulation of hydrological processes in a meso-scale basin (101–103km2), the spatially and temporally variable basin inputs (precipitation and energy) and runoff generation processes need to be adequately addressed by the model. The catchment model TACD (tracer aided catchment model, distributed) is based on experimental results including tracer studies at the mountainous Brugga basin (40

Stefan Uhlenbrook; Stefan Roser; Nils Tilch

2004-01-01

110

Quantitative catchment profiling to apportion faecal indicator organism budgets for the Ribble system, the UK's sentinel drainage basin for Water Framework Directive research  

Microsoft Academic Search

Under the EU Water Framework Directive (WFD) 20\\/60\\/EC and the US Federal Water Pollution Control Act 2002 management of water quality within river drainage basins has shifted from traditional point-source control to a holistic approach whereby the overall contribution of point and diffuse sources of pollutants has to be considered. Consequently, there is a requirement to undertake source-apportionment studies of

C. M. Stapleton; M. D. Wyer; J. Crowther; A. T. McDonald; D. Kay; J. Greaves; A. Wither; J. Watkins; C. Francis; N. Humphrey; M. Bradford

2008-01-01

111

Preliminary gravity inversion model of basins east of Yucca Flat, Nevada Test Site, Nevada.  

SciTech Connect

The Yucca Flat eastern extension study area, a 14 kilometer by 45 kilometer region contiguous to Yucca Flat on the west and Frenchman Flat on the south, is being studied to expand the boundary of the Yucca Flat hydrogeologic model. The isostatic residual gravity anomaly was inverted to create a model of the depth of the geologic basins within the study area. Such basins typically are floored by dense pre-Tertiary basement rocks and filled with less-dense Tertiary volcanic and sedimentary rocks and Quaternary alluvium, a necessary condition for the use of gravity modeling to predict the depth to the pre-Tertiary basement rocks within the basins. Three models were created: a preferred model to represent the best estimate of depth to pre-Tertiary basement rocks in the study area, and two end-member models to demonstrate the possible range of solutions. The preferred model predicts shallow basins, generally less than 1,000m depth, throughout the study area, with only Emigrant Valley reaching a depth of 1,100m. Plutonium valley and West Fork Scarp Canyon have maximum depths of 800m and 1,000m, respectively. The end-member models indicate that the uncertainty in the preferred model is less than 200m for most of the study area.

Geoffrey A. Phelps; Carter W. Roberts, and Barry C. Moring

2006-03-17

112

Tectonic Evolution of the Ohrid Basin (Macedonia/Albania): preliminary results for a future ICDP deep drilling site  

NASA Astrophysics Data System (ADS)

In the frame of the planned ICDP deep drilling site within the Lake Ohrid (Macedonia/Albania, SCOPSCO initiative), we are focusing on the tectonic framework of the site. The Ohrid basin is an important N-S trending graben structure in Macedonia/Albania and located within the Afro-European Convergence Zone a region with dispersed active seismicity. In contrast to the compressive coastal part of Albania the central and eastern part are presently subject to extension. Earthquake focal mechanisms showed active N-S normal faulting with horst and graben structures, in a basin and range like environment. Several pronounced scarps testify to an active, seismogenic landscape as revealed also from DEM data. Paleozoic metamorphic and magmatic rocks form the country rock of the Western Macedonian Zone around Lake Ohrid. Triassic carbonates and clastics are widely exposed to the southeast and northwest of the lake. These rocks bear the imprints of several deformation phases that affected the basin system since the Late Cretaceous to present. However, until today the different steps in the tectonic evolution of the graben is not clear. Therefore, we started to investigate the (neo)tectonic evolution of Lake Ohrid with a field campaign focusing on the collection of structural data, like paleostress data (fault-slip data) and mapping of folds, joints and fractures. We studied a total of 24 sites along the steep flanks and the mountains surrounding Lake Ohrid, with suitable fault-slip data for stress inversion. At each location we measured a representative number of fault planes concerning the spatial orientation of fault plane (dip direction, dip) and striae (azimuth, plunge) and additional the sense of slip (reverse, normal, dextral or sinistral). After separation and classification of the data the preliminary results already show a tendency of three major deformation phases affecting the surroundings of Ohrid Basin: NW-SE, NE-SW horizontal contraction and later an almost vertical uplift with E-W extension. The multiple inverse method of Yamaji (2000) was applied on datasets with a polyphase stress history and to investigate the spatial and temporal variations of paleostresses in the Ohrid Basin. The applied methods led us to the following preliminary results: - Three main phases of deformation can be assumed NW-SE shortening, NE-SW shortening and a present-day extension - Morphological lineations, which are directed NNE-SSW, NW-SE, and E-W fit in the assumed pattern of faults - Earthquake focal solutions and data of the world stress map data point to SW-NE directed extension and normal faulting acting presently - The origin of the lake formation is unclear, possibly an older tectonic transtensional phase or reactivation of inherited faults led to a pull-apart like opening of the basin, followed by E-W directed extension. Reference: Yamaji, A., 2000. The multiple inverse method: a new technique to separate stresses from heterogeneous fault-slip data. J. Struct. Geol. 22, 441-452

Hoffmann, N.; Reicherter, K.; Fernández-Steeger, T.; Arndt, M.

2009-04-01

113

A Preliminary Investigation of the Yallalie Basin: A Buried 15 KM Diameter Structure of Possible Impact Origin in the Perth Basin, Western Australia  

NASA Astrophysics Data System (ADS)

In late 1990, Ampol Exploration drew the attention of the senior author to an enigmatic structure located in Mesozoic rocks in the Dandaragan Trough of the Perth Basin about 200 km north of Perth, Western Australia. The basin-like Yallalie structure, centred on coordinates ca. 30 degrees 28'S, 115 degrees 47'E, is subcircular in plan view and about 15 km in diameter. Recognizing structures beneath the basin likely to contain oil, Ampol carried out an intensive geophysical survey of the area, and subsequently drilled a well (Yallalie 1). The well proved to be dry and exploration ceased. Generously, Ampol and their partners have made available the results of their exploration for a research project into the nature of the structure. Geology and regional setting: The exposed geology of the Yallalie basin area comprises discontinuous sequences of sedimentary rocks (sandstones, siltstones and shales) of Middle Jurassic to Late Cretaceous age that are capped by laterite and locally covered by thin (<50 m) Cenozoic eolian, colluvial and alluvial deposits (Cockbain, 1990). Modern, high-resolution, seismic reflection profiles across the Yallalie structure show a basin-shaped area of chaotic reflections that extend down to a depth of approximately 2 km below the surface. The structure has sharp boundaries with surrounding faulted, but otherwise relatively undisturbed rocks. At the base of the structure there is a central uplifted area approximately 3-4 km across similar to those described from complex impact structures (Dence et al., 1977). A preliminary survey of the area has shown that exposed rocks of the Yarragadee Formation (Middle Jurassic to Lower Cretaceous) and the succeeding Warnbro (Lower Cretaceous) and Coolyena (Late Cretaceous) Groups dip gently and their deposition appears to have postdated the underlying structure of intensely disturbed rocks. Although the structure is "draped" by a thin (a few hundred metres) veneer of late Jurassic to Cretaceous rocks it has some surface expression. A broad depression approximately 120 m deep is centered on Yallalie Well and is bounded to the west and north by a marked "rim." The area is characterized by a radial pattern of drainage that flows into the depression and which is gradually exhuming the buried structure. A southerly flowing stream drains the depression and has breached the "rim" to the south. Evidence for impact at Yallalie: Quartz grains taken from the core at a depth of 430-460 m in the Yallalie 1 well show widesprad development of prismatic cleavage fractures and irregular, slightly curved planes formed by brittle fracture. Quartz grains from a depth of 150-180 m in the well are essentially undeformed (McInerney, 1991). However, multiple sets of closely spaced planar features in quartz, characteristic of highly shocked rocks, have yet to be observed in core material from the Yallalie structure. Nevertheless, the morphology of the Yallalie structure determined from geophysical data suggests strongly that it is of impact origin. Work is continuing on the core material to search for diagnostic shock-metamorhic effects, and to constrain the age of the structure. References Cockbain A. E. (1990) In Geology and Mineral Resources of Western Australia, Western Australia Geological Survey, Memoir 3, pp. 514-516. Dence M. R., Grieve R. A. F., and Robertson P. B. (1977) In Impact and Explosion Cratering (eds. D. J. Roddy, R. O. Pepin, and R. B. Merrill), Pergamon Press, pp. 247-275. McInerney K. B. (1991) Honors Thesis (unpublished), University of Western Australia.

Dentith, M. C.; Bevan, A. W. R.; McInerney, K. B.

1992-07-01

114

Neural Networks for Real Time Catchment Flow Modeling and Prediction  

Microsoft Academic Search

Accurate prediction of catchment flow has been recognized as an important measures for effective flood-risk management strategy.\\u000a A neural network modeling approach was used to construct a real time catchment flow prediction model for a river basin. Two\\u000a types of neural network architectures i.e. feed forward and recurrent neural networks, and three types of training algorithm\\u000a i.e. Levenberg–Marquardt, Bayesian regularization,

Muhammad Aqil; Ichiro Kita; Akira Yano; Soichi Nishiyama

2007-01-01

115

New Seismic Reflection Profiling Across the Northern Newark Basin USA: Data Acquisition and Preliminary Results  

NASA Astrophysics Data System (ADS)

Deep saline formations in basins underlying major population centers represent opportunities for carbon (CO2) sequestration, but intensive surface development in such settings can hinder field operations to acquire geologic and geophysical data critical to effective characterization. Seismic-reflection is a tool that can be used to characterize basins and their potential capacity for carbon storage. The northern part of the Triassic-Jurassic Newark Rift Basin represents a potential storage opportunity for carbon as a result of its proximity to large-scale CO2 emitters; however, a lack of deep geologic and seismic data from this area has precluded evaluation of this basin to date. As part of the Department of Energy's (DOE) National Energy Technology Labs (NETL) Carbon Sequestration programs portion of the American Recovery and Reinvestment Act (ARRA)- and NYSERDA-funded TriCarb Consortium for Carbon Sequestration basin characterization project, two new seismic-reflection profiles were acquired in the northern portion of the Newark Basin in Rockland County, NY and Bergen County NJ. This densely developed region, proximal to New York City, presents a variety of challenges for seismic surveys, including route selection and access, community acceptance, high traffic volumes and associated data noise, in addition to regulatory requirements and private property limitations. In spite of these challenges, two high-resolution, perpendicular lines were successfully surveyed in late March and early April, 2011; one dip line extending 21 km (13 mi) across most of the basin (east-west), and a shorter strike line extending 8 km (5 mi, north-south). The survey lines intersected near the location of a planned 8,000 ft stratigraphic borehole to be drilled by the TriCarb consortium. Three vibroseis trucks comprised the source array. Source points were spaced at 36.5 m (120-ft) intervals and geophone accelerometers collected data at a 3.05 m (10 ft) intervals. Seismic-reflection data processing included three main objectives: 1) attenuate high levels of noise related to the high volume traffic, 2) constrain the depth and thickness of the diabase sill at the planned borehole site and 3) optimize the image of potential reservoirs relative to the diabase sill. The high volume traffic noise was successfully removed from the data using several attenuation algorithms. Refraction statics were selected individually to improve reflector coherency over the automated solution and single sensor data were used throughout to maximize frequency bandwidth and reduce smearing related to the offset 2D geometry. In general, these techniques revealed a well-defined basin image that exhibits structural characteristics of an eroded half graben. The diabase sill and potential reservoirs appear to be well-imaged near the planned borehole site. The successful completion of this survey and final product demonstrate that geophysical data acquisition can be achieved in highly developed regions that have carbon storage potential.

Tymchak, M.; Collins, D.; Brown, C.; Conrad, J.; Papadeas, P.; Coueslan, M. L.; Tamulonis, K.; Goldberg, D.; Olsen, P. E.

2011-12-01

116

Preliminary selection of sustainability indicators for a small lake basin in Western México  

Microsoft Academic Search

Lake Zapotlán is a small (1100 ha) lake in Jalisco state, western Mexico. Two communities are located within the basin (Ciudad Guzman, population ?93,000 and Gomez Farías, population ?12,000). The lake has a productive fishery (annual harvest between 200 and 570 tonnes) comprising tilapia and carp. Extensive beds of rooted and floating Typha latifolia are found in the lake and are

Harvey Shear; José de Anda

2009-01-01

117

Preliminary gravity inversion model of Frenchman Flat Basin, Nevada Test Site, Nevada  

SciTech Connect

The depth of the basin beneath Frenchman Flat is estimated using a gravity inversion method. Gamma-gamma density logs from two wells in Frenchman Flat constrained the density profiles used to create the gravity inversion model. Three initial models were considered using data from one well, then a final model is proposed based on new information from the second well. The preferred model indicates that a northeast-trending oval-shaped basin underlies Frenchman Flat at least 2,100 m deep, with a maximum depth of 2,400 m at its northeast end. No major horst and graben structures are predicted. Sensitivity analysis of the model indicates that each parameter contributes the same magnitude change to the model, up to 30 meters change in depth for a 1% change in density, but some parameters affect a broader area of the basin. The horizontal resolution of the model was determined by examining the spacing between data stations, and was set to 500 square meters.

Phelps, G.A.; Graham, S.E.

2002-10-01

118

Preliminary gravity inversion model of Frenchman Flat Basin, Nevada Test Site, Nevada  

USGS Publications Warehouse

The depth of the basin beneath Frenchman Flat is estimated using a gravity inversion method. Gamma-gamma density logs from two wells in Frenchman Flat constrained the density profiles used to create the gravity inversion model. Three initial models were considered using data from one well, then a final model is proposed based on new information from the second well. The preferred model indicates that a northeast-trending oval-shaped basin underlies Frenchman Flat at least 2,100 m deep, with a maximum depth of 2,400 m at its northeast end. No major horst and graben structures are predicted. Sensitivity analysis of the model indicates that each parameter contributes the same magnitude change to the model, up to 30 meters change in depth for a 1% change in density, but some parameters affect a broader area of the basin. The horizontal resolution of the model was determined by examining the spacing between data stations, and was set to 500 square meters.

Phelps, Geoffrey A.; Graham, Scott E.

2002-01-01

119

Meso-scale catchment sediment budgets: combining field surveys and modeling in the Dragonja catchment, SW Slovenia  

Microsoft Academic Search

In this paper, we present a methodology to construct a sediment budget for meso-scale catchments. We combine extensive field surveys and expert knowledge of the catchment with a sediment delivery model. The meso-scale Mediterranean drainage basin of the Dragonja (91 km2), southwest Slovenia, was chosen as case study area. During the field surveys, sheet wash was observed on sloping agricultural

S. D. Keesstra; L. A. Bruijnzeel; J. van Huissteden

2009-01-01

120

Regional stochastic estimation of the groundwater catchment for distributed hydrological modelling  

NASA Astrophysics Data System (ADS)

Rainfall-runoff modeling typically assumes that the groundwater catchment boundary coincide with the topographic one. While this is often a reasonable assumption for large and and mesoscale catchments (> 103 km2), this assumption may lead to large errors of streamflow in small scale catchments (? 102 km2), in particular in certain geological settings. The Ammer catchment (135 km2) in the upper Neckar river basin (Germany) is a prime example where groundwater and topographic catchment boundaries are significantly distinct from each other. The catchment is characterized by a complex sequence of fractured, karstic Triassic rock formations. These strata gently dip into ESE direction governing groundwater flow. Analysis of tracer experiments conducted in the 1970s indicates that the boundary overlap could be less than 80 percent. Further, a modelling study of the upper Neckar river basin using the distributed hydrological model mHM showed Nash-Sutcliff efficiencies (NSE) < 0.4 for simulated runoff in the Ammer sub-basin whereas higher efficiencies (NSE ~ 0.7) were obtained for most of the other 21 sub basins in the region. In this study we present a methodology to simultaneously estimate the regional groundwater catchment boundaries of the Ammer and its surrounding basins. In a first step we derive the best possible fit between mHM simulated and observed runoff for the individual sub-basins in the Ammer region and determine the trade-off between the fits of the individual basins using the muliobjective optimization method AMALGAM. We further present a strategy to estimate the regional groundwater catchment boundaries with the aim to improve runoff predictions in the Ammer catchment while not deteriorating runoff predictions in the surrounding basins. Our strategy involves a modification of the mHM model to account for ground water import/export from neighboring catchments while maintaining full mass balance of the surrounding basins. Groundwater catchment boundaries are then obtained by innovative stochastic optimization techniques based on Simulated Annealing that are constrained by expert knowledge about the hydrological system, e.g. a minimum overlap of groundwater and topographical catchment boundaries. The methods developed herein are useful for both plausibility and hypothesis testing as well as hydrological modelling of small scale catchments where conventional models fail due to the mismatch between groundwater and topographical catchment boundaries.

Wöhling, Th.; Samaniego, L.; Selle, B.; Kumar, R.; Zink, M.

2012-04-01

121

Nutrient removal using biosorption activated media: preliminary biogeochemical assessment of an innovative stormwater infiltration basin.  

PubMed

Soil beneath a stormwater infiltration basin receiving runoff from a 23 ha predominantly residential watershed in north-central Florida, USA, was amended using biosorption activated media (BAM) to study the effectiveness of this technology in reducing inputs of nitrogen and phosphorus to groundwater. The functionalized soil amendment BAM consists of a 1.0:1.9:4.1 mixture (by volume) of tire crumb (to increase sorption capacity), silt and clay (to increase soil moisture retention), and sand (to promote sufficient infiltration), which was applied to develop an innovative stormwater infiltration basin utilizing nutrient reduction and flood control sub-basins. Comparison of nitrate/chloride (NO(3)(-)/Cl(-)) ratios for the shallow groundwater indicates that prior to using BAM, NO(3)(-) concentrations were substantially influenced by nitrification or variations in NO(3)(-) input. In contrast, for the new basin utilizing BAM, NO(3)(-)/Cl(-) ratios indicate minor nitrification and NO(3)(-) losses with the exception of one summer sample that indicated a 45% loss. Biogeochemical indicators (denitrifier activity derived from real-time polymerase chain reaction and variations in major ions, nutrients, dissolved and soil gases, and stable isotopes) suggest that NO(3)(-) losses are primarily attributable to denitrification, whereas dissimilatory nitrate reduction to ammonium is a minor process. Denitrification was likely occurring intermittently in anoxic microsites in the unsaturated zone, which was enhanced by the increased soil moisture within the BAM layer and resultant reductions in surface/subsurface oxygen exchange that produced conditions conducive to increased denitrifier activity. Concentrations of total dissolved phosphorus and orthophosphate (PO(4)(3-)) were reduced by more than 70% in unsaturated zone soil water, with the largest decreases in the BAM layer where sorption was the most likely mechanism for removal. Post-BAM PO(4)(3-)/Cl(-) ratios for shallow groundwater indicate predominantly minor increases and decreases in PO(4)(3-) with the exception of one summer sample that indicated a 50% loss. Differences in nutrient variations between the unsaturated zone and shallow groundwater may be the result of the intensity and duration of nutrient removal processes and mixing ratios with water that had undergone little biogeochemical transformation. Observed nitrogen and phosphorus losses demonstrate the potential, as well as the future research needs to improve performance, of the innovative stormwater infiltration basin using BAM for providing passive, economical, stormwater nutrient-treatment technology to support green infrastructure. PMID:22742948

O'Reilly, Andrew M; Wanielista, Martin P; Chang, Ni-Bin; Xuan, Zhemin; Harris, Willie G

2012-06-26

122

Modeling sediment yields in Italian catchments  

Microsoft Academic Search

Sediment yield observations, derived from 40 long-term sedimentation records in Italian reservoirs, were used to calibrate and validate the spatially distributed sediment delivery model WaTEM\\/SEDEM using the best data available at national scale. The sediment yield data set includes records from semi-natural catchments in northern Italy as well as agricultural and semi-natural basins in central and southern Italy. The average

Anton Van Rompaey; Paolo Bazzoffi; Robert J. A. Jones; Luca Montanarella

2005-01-01

123

MODELLING SEDIMENT YIELDS IN ITALIAN CATCHMENTS  

Microsoft Academic Search

ABSTRACT Long term sediment yield observations, derived from 40 long term sedimentation records in Italian reservoirs, were used to calibrate and validate the spatially distributed sediment delivery model,WaTEM\\/SEDEM using the best data available at national scale. The sediment yield data set includes records from semi-natural catchments in northern Italy as well and agricultural and semi-natural basins in central and southern

Anton Van Rompaey; Paolo Bazzoffi; Robert J. A Jones; Luca Montanarella

2005-01-01

124

Towards a catchment-scale macro-ecological model to support integrated catchment management in Europe  

NASA Astrophysics Data System (ADS)

In Europe, the Water Framework Directive (WFD) is providing a powerful regulatory driver to adopt integrated catchment management, and so pressurizing researchers to build suitable supporting tools. The WFD requires agencies to drive towards `good ecological quality' by 2015. After the initial step of characterising water bodies and the pressures on them, the next substantive step is the preparation of river basin management plans and proposed programmes of measures by 2009. Ecological quality is a complex concept and poorly defined, unless it is taken as a simple measure such as the abundance of a particular species of organism. There is clearly substantial work to do to build a practical but sound definition of ecological quality; practical in the sense of being easy to measure and explain to stakeholders, and sound in the sense that it reflects ecological complexity within catchments, the variability between catchments, and the conflicts demands for goods and services that human society places upon the ecological system. However ecological quality is defined, it will be driven by four interacting groups of factors. These represent the physical, chemical, ecological and socio-economic environments within and encompassing the catchment. Some of these groupings are better understood than others, for example hydrological processes and the transport of solutes are reasonably understood, even though they remain research areas in their own right. There are much larger gaps in our understanding at the interfaces, i.e. predicting how, for example, hydrological processes such as flow and river morphology influence ecological quality. Overall, it is clear we are not yet in a position to build deterministic models of the overall ecological behaviour of catchment. But we need predictive tools to support catchment management agencies in preparing robust plans. This poster describes our current exploration of soft modelling options to build a comprehensive macro-ecological model of UK catchments. This is taking place within the Catchment Science Centre, a joint venture between the University of Sheffield and the Environment Agency.

Lerner, R. N.; Lerner, D. N.; Surridge, B.; Paetzold, A.; Harris, B.; Anderson, C. W.

2005-12-01

125

Preliminary Measurements Of N2O Partial Pressures In Rivers of Amazon Basin, Brazil  

Microsoft Academic Search

The concentrations of nitrous oxide (N2O), an important component of the greenhouse effect and with a long residence time in the atmosphere, have significantly increased in this century. The reasons for this atmospheric increase in N2O are still partially unexplained. This uncertainty is worse in relation to aquatic environments. Here we report on preliminary measurements of N2O partial pressures in

C. B. Oliveira; M. F. Rasera; A. V. Krusche; R. L. Victoria; J. E. Richey; H. B. Cunha; B. M. Gomes

2006-01-01

126

Preliminary Classification of Water Areas Within the Atchafalaya Basin Floodway System by Using Landsat Imagery  

USGS Publications Warehouse

The southern portion of the Atchafalaya Basin Floodway System (ABFS) is a large area (2,571 km2) in south central Louisiana bounded on the east and west sides by a levee system. The ABFS is a sparsely populated area that includes some of the Nation's most significant extents of bottomland hardwoods, swamps, bayous, and backwater lakes, holding a rich abundance and diversity of terrestrial and aquatic species. The seasonal flow of water through the ABFS is critical to maintaining its ecological integrity. Because of strong interdependencies among species, habitat quality, and water flow in the ABFS, there is a need to better define the paths by which water moves at various stages of the hydrocycle. Although river level gages have collected a long historical record of water level variation, very little synoptic information has been available regarding the distribution and character of water at more remote locations in the basin. Most water management plans for the ABFS strive to improve water quality by increasing water flow and circulation from the main stem of the Atchafalaya River into isolated areas. To describe the distribution of land and water on a basin-wide scale, we chose to use Landsat 5 and Landsat 7 imagery to determine the extent of water distribution from 1985 to 2006 and at a variety of river stages. Because the visual signature of river water is high turbidity, we also used Landsat imagery to describe the distribution of turbid water in the ABFS. The ability to track water flow patterns by tracking turbid waters will enhance the characterization of water movement and aid in planning.

Allen, Yvonne C.; Constant, Glenn C.; Couvillion, Brady R.

2008-01-01

127

Modeling the Caspian Sea and its catchment area using a coupled regional atmosphere-ocean model (RegCM-ROMS): model design and preliminary results  

NASA Astrophysics Data System (ADS)

We describe the development of a coupled regional atmosphere-ocean model (RegCM-ROMS) and its implementation over the Caspian Sea basin. The coupled model is run for the period 1999-2008 (after a spin up of 4 yr) and it is compared to corresponding stand alone model simulations and a simulation in which a distributed 1d lake model is run for the Caspian Sea. All model versions show a good performance in reproducing the climatology of the Caspian Sea basin, with relatively minor differences across them. The coupled ROMS produces realistic, although somewhat overestimated, lake surface temperatures (LSTs), with a considerable improvement compared to the use of the simpler coupled lake model. Simulated near surface salinity and sea currents are also realistic, although the upwelling over the eastern coastal regions is underestimated. The distribution of sea ice over the shallow northern shelf of the Caspian Sea and its seasonal evolution are well reproduced. ROMS also calculates the Caspian Sea Level (CSL), showing that for the present experiment excessive evaporation over the lake area leads to a drift in estimated CSL. Despite this problem which requires further analysis due to many uncertainties in the estimation of CSL, overall the coupled RegCM-ROMS system shows encouraging results in reproducing both the climatology of the region and the basic characteristics of the Caspian Sea.

Turuncoglu, U. U.; Giuliani, G.; Elguindi, N.; Giorgi, F.

2012-11-01

128

Modelling the Caspian Sea and its catchment area using a coupled regional atmosphere-ocean model (RegCM4-ROMS): model design and preliminary results  

NASA Astrophysics Data System (ADS)

We describe the development of a coupled regional atmosphere-ocean model (RegCM4-ROMS) and its implementation over the Caspian Sea basin. The coupled model is run for the period 1999-2008 (after a spin up of 4 yr) and it is compared to corresponding stand alone model simulations and a simulation in which a distributed 1d lake model is run for the Caspian Sea. All model versions show a good performance in reproducing the climatology of the Caspian Sea basin, with relatively minor differences across them. The coupled ROMS produces realistic, although somewhat overestimated, Caspian Sea Surface Temperature (SST), with a considerable improvement compared to the use of the simpler coupled lake model. Simulated near surface salinity and sea currents are also realistic, although the upwelling over the eastern coastal regions is underestimated. The sea ice extent over the shallow northern shelf of the Caspian Sea and its seasonal evolution are well reproduced, however, a significant negative bias in sea-ice fraction exists due to the relatively poor representation of the bathymetry. ROMS also calculates the Caspian Sea Level (CSL), showing that for the present experiment excessive evaporation over the lake area leads to a drift in estimated CSL. Despite this problem, which requires further analysis due to many uncertainties in the estimation of CSL, overall the coupled RegCM4-ROMS system shows encouraging results in reproducing both the climatology of the region and the basic characteristics of the Caspian Sea.

Turuncoglu, U. U.; Giuliani, G.; Elguindi, N.; Giorgi, F.

2013-03-01

129

Modeling the Caspian Sea and its catchment area using a coupled regional atmosphere-ocean model (RegCM-ROMS): model design and preliminary results  

NASA Astrophysics Data System (ADS)

We describe the development of a coupled regional atmosphere-ocean model (RegCM-ROMS) and its implementation over the Caspian Sea basin. The coupled model is run for the period 1999-2008 (after a spin up of 4 yr) and it is compared to corresponding stand alone model simulations and a simulation in which a distributed 1d lake model is run for the Caspian Sea. All model versions show a good performance in reproducing the climatology of the Caspian Sea basin, with relatively minor differences across them. The coupled ROMS produces realistic, although somewhat overestimated, lake surface temperatures (LSTs), with a considerable improvement compared to the use of the simpler coupled lake model. Simulated near surface salinity and sea currents are also realistic, although the upwelling over the eastern coastal regions is underestimated. The distribution of sea ice over the shallow northern shelf of the Caspian Sea and its seasonal evolution are well reproduced. ROMS also calculates the Caspian Sea Level (CSL), showing that for the present experiment excessive evaporation over the lake area leads to a drift in estimated CSL. Despite this problem which requires further analysis due to many uncertainties in the estimation of CSL, overall the coupled RegCM-ROMS system shows encouraging results in reproducing both the climatology of the region and the basic characteristics of the Caspian Sea.

Turuncoglu, Ufuk; Giuliani, Graziano; Elguindi, Nellie; Giorgi, Filippo

2013-04-01

130

Stream macroinvertebrate response to catchment urbanisation (Georgia, U.S.A.)  

Microsoft Academic Search

SUMMARY 1. The effects of catchment urbanisation on water quality were examined for 30 streams (stratified into 15, 50 and 100 km2 ±2 5% catchments) in the Etowah River basin, Georgia, U.S.A. We examined relationships between land cover (implying cover and use) in these catchments (e.g. urban, forest and agriculture) and macroinvertebrate assemblage attributes using several previously published indices to

A. H. R OY; A. D. R OSEMOND; J. B. W ALLACE; Owings Mills

2003-01-01

131

Inferring catchment precipitation by doing hydrology backward: A test in 24 small and mesoscale catchments in Luxembourg  

NASA Astrophysics Data System (ADS)

The complexity of hydrological systems and the necessary simplification of models describing these systems remain major challenges in hydrological modeling. Kirchner's (2009) approach of inferring rainfall and evaporation from discharge fluctuations by "doing hydrology backward" is based on the assumption that catchment behavior can be conceptualized with a single storage-discharge relationship. Here we test Kirchner's approach using a densely instrumented hydrologic measurement network spanning 24 geologically diverse subbasins of the Alzette catchment in Luxembourg. We show that effective rainfall rates inferred from discharge fluctuations generally correlate well with catchment-averaged precipitation radar estimates in catchments ranging from less than 10 to more than 1000 km2 in size. The correlation between predicted and observed effective precipitation was 0.8 or better in 23 of our 24 catchments, and prediction skill did not vary systematically with catchment size or with the complexity of the underlying geology. Model performance improves systematically at higher soil moisture levels, indicating that our study catchments behave more like simple dynamical systems with unambiguous storage-discharge relationships during wet conditions. The overall mean correlation coefficient for all subbasins for the entire data set increases from 0.80 to 0.95, and the mean bias for all basins decreases from -0.61 to -0.35 mm d-1. We propose an extension of Kirchner's approach that uses in situ soil moisture measurements to distinguish wet and dry catchment conditions.

Krier, R.; Matgen, P.; Goergen, K.; Pfister, L.; Hoffmann, L.; Kirchner, J. W.; Uhlenbrook, S.; Savenije, H. H. G.

2012-10-01

132

Elemental composition in sediments and water in the Trancão river basin. A preliminary study  

NASA Astrophysics Data System (ADS)

The Trancão river basin, located in the Lisbon area shows preoccupying pollution levels, that constitute a threat to public health and the ecological system. This work reports on the results obtained in the analysis of surface sediments (EDXRF) and water (PIXE) collected in the wet and dry season during 1996. In general, bulk sediments and water show high concentration levels for some heavy metals like Cr, Cu, Zn and Pb. The elemental contents variation of samples collected at the different sites of the river basin were large, owing apparently to pollution sources, seasonal variabilities and grain size distribution (sediments). In the dry season, effluents (industrial and domestic) showed a stronger influence on the sediment composition. High levels of As and Br were found in the water that can be attributed to extended sources like sewage sludge and fertilizers. In some locations, the metals, Ca and organic matter enrichment could be associated with a paper mill and metal processing industry (high levels of Cr). At the estuary, the decrease of metal content determined in the sampled water indicates the flocculation of dissolved organic and inorganic materials. However, no effects were found for the surface sediment metal content, probably due to a dilution with materials from the Tagus inner estuary (the largest in Portugal).

Araújo, F.; Pinheiro, T.; Alves, L. C.; Valério, P.; Gaspar, F.; Alves, J.

1998-03-01

133

Preliminary study of the hydrologic response of an urban drainage basin at two different scales  

NASA Astrophysics Data System (ADS)

Predicted changes in climate and urban sprawl areas are expected to cause significant modification in rainfall pattern and hydrological regimes. Urbanization can alter the hydrologic response by increasing streamflow, reducing time of concentration, altering soil moisture levels and increasing overland flow, thereby increasing the size, frequency and speed of peak flow responses. However, despite the profusion of works, effective methodologies to investigate the impacts of potential land-use change on how spatial variability of soil moisture and precipitation affect runoff production at a range of scales and on different land uses remain largely undeveloped. This has important implications for flood prediction accuracy. The main aim of this work is to assess the hydrological response and to understand the influence of different land uses. The study is based on a small urban drainage basin (7 Km2), undergoing rapid urbanization, located in central Portugal: Ribeira dos Covões. It considers a combined approach of field survey and data acquisition to access spatiotemporal dynamics and land uses contributions to surface hydrology, based on drainage basins and small plot scales. At drainage basin scale, the study is based on three years rainfall and stream flow data analysis (collected through an automatic water level recorder and rain gauges). Rainfall-runoff relationship was assessed over the time and isolated events were studied. To understand land uses on the hydrology, rainfall simulations were conducted at the small plot scale (0.25 m2) during a dry period, in forested and deforested areas, agricultural areas, including tilled and abandoned areas, as well as built-up areas (21 experiments with 1 hour duration, with a rain intensity of 43±3 mm h-1). During the experiments hydrophobicity was monitored (Molarity of an Ethanol Droplet technique), soil moisture content was assessed every minute, and runoff volume was measured every 5 minutes. This work has shown the existence of different spatial and temporal variations on hydrological processes. At drainage basin scale, runoff coefficient varied between around 5% of the rainfall for a dry year (2005), to around 15% in a wet year (2007). The hydrological response to rainfall simulation experiments is significantly different according to the land use. In agriculture areas overland flow did not occur or was negligible. However, in forest and clear felled areas the overland flow coefficient ranged between 20% and 80% of total rainfall, while in construction areas the values were higher: 55% and 95%. However, the overland flow did?t seem to be yielded by saturation. Considering the low moisture content when overland flow started, hydrological response in some plots can only be explained by the hydrophobic soil behaviour registered and/or macrospore collapse. This research confirms the importance of land use in overland flow processes and points out the difficulties in upscalling hydrologic response of complex urban drainage basins. The differences registered in both scales revealed contradictory results, so rainfall simulation results should be interpreted carefully according with the specific antecedent soil conditions and rainfall characteristics simulated. The abundance of different overland flow generating sources may increase and decrease depending on previous climatic conditions and land use.

Ferreira, Carla; Ferreira, António; Coelho, Celeste; de Lima João, Pedroso

2010-05-01

134

Total mercury concentrations in an industrialized catchment, the Thur River basin (north-eastern France): geochemical background level and contamination factors.  

PubMed

River bottom sediments and soils were collected from the industrialized Thur River basin (north-eastern France) to assess mercury contamination. The regional geochemical background level of total mercury was evaluated to calculate mercury contamination factors (Fc) in soils and river bottom sediments. Our estimate of the mean background mercury levels in river sediments and soils, not affected by human activities, was 232 ng x g(-1) (range: 27-406 ng x g(-1)). Sediments contaminated by the effluent from a chlor-alkali plant yielded the highest contamination factors (Fc=1784). Contamination factors of surficial soils within 1 km of the industrial site range from 6.3 to 43.6. This contamination is attributed to diffuse atmospheric deposition from this local plant. However, even upstream from this industrial area elevated contamination factors were recorded for river bottom sediments (Fc=3.2 to 26.4) and for one alluvial soil profile (Fc=10). This is possibly due to past pollution resulting from waste water discharges. Mercury contamination in the different horizons of alluvial soils is not correlated with soil organic carbon content, but may be the result of occasional accidental pollution arising from the introduction of contaminated suspended particulate matter by the Thur River during periods of flooding. PMID:12738301

Rémy, S; Prudent, P; Hissler, C; Probst, J L; Krempp, G

2003-07-01

135

Mid-Neolithic exploitation of mollusks in the Guanzhong Basin of Northwestern China: preliminary results.  

PubMed

Mollusk remains are abundant in archaeological sites in the Guanzhong Basin of Northwestern China, providing good opportunities for investigations into the use of mollusks by prehistoric humans. Here we report on freshwater gastropod and bivalve mollusks covering the time interval from about 5600 to 4500 cal. yrs BP from sites of Mid-Late Neolithic age. They are identified as Cipangopaludina chinensis and Unio douglasiae, both of which are currently food for humans. The shells are well preserved and have no signs of abrasion. They are all freshwater gastropods and bivalves found in pits without water-reworked deposits and have modern representatives which can be observed in rivers, reservoirs, and paddy fields in the studied region. Mollusk shells were frequently recovered in association with mammal bones, lithic artifacts, and pottery. These lines of evidence indicate that the mollusks are the remains of prehistoric meals. The mollusk shells were likely discarded into the pits by prehistoric humans after the flesh was eaten. However, these mollusk remains may not have been staple food since they are not found in large quantities. Mollusk shell tools and ornaments are also observed. Shell tools include shell knives, shell reaphooks and arrowheads, whereas shell ornaments are composed of pendants and loops. All the shell tools and ornaments are made of bivalve mollusks and do not occur in large numbers. The finding of these freshwater mollusk remains supports the view that the middle Holocene climate in the Guanzhong Basin may have been warm and moist, which was probably favorable to freshwater mollusks growing and developing in the region. PMID:23544050

Li, Fengjiang; Wu, Naiqin; Lu, Houyuan; Zhang, Jianping; Wang, Weilin; Ma, Mingzhi; Zhang, Xiaohu; Yang, Xiaoyan

2013-03-18

136

Design and development of a wireless sensor network to monitor snow depth in multiple catchments in the American River basin, California: hardware selection and sensor placement techniques  

NASA Astrophysics Data System (ADS)

A 100-node wireless sensor network (WSN) was designed for the purpose of monitoring snow depth in two watersheds, spanning 3 km2 in the American River basin, in the central Sierra Nevada of California. The network will be deployed as a prototype project that will become a core element of a larger water information system for the Sierra Nevada. The site conditions range from mid-elevation forested areas to sub-alpine terrain with light forest cover. Extreme temperature and humidity fluctuations, along with heavy rain and snowfall events, create particularly challenging conditions for wireless communications. We show how statistics gathered from a previously deployed 60-node WSN, located in the Southern Sierra Critical Zone Observatory, were used to inform design. We adapted robust network hardware, manufactured by Dust Networks for highly demanding industrial monitoring, and added linear amplifiers to the radios to improve transmission distances. We also designed a custom data-logging board to interface the WSN hardware with snow-depth sensors. Due to the large distance between sensing locations, and complexity of terrain, we analyzed network statistics to select the location of repeater nodes, to create a redundant and reliable mesh. This optimized network topology will maximize transmission distances, while ensuring power-efficient network operations throughout harsh winter conditions. At least 30 of the 100 nodes will actively sense snow depth, while the remainder will act as sensor-ready repeaters in the mesh. Data from a previously conducted snow survey was used to create a Gaussian Process model of snow depth; variance estimates produced by this model were used to suggest near-optimal locations for snow-depth sensors to measure the variability across a 1 km2 grid. We compare the locations selected by the sensor placement algorithm to those made through expert opinion, and offer explanations for differences resulting from each approach.

Kerkez, B.; Rice, R.; Glaser, S. D.; Bales, R. C.; Saksa, P. C.

2010-12-01

137

Exhumation of the Magallanes foreland basin, Patagonian Andes, Chile (51 °S): Preliminary results from apatite (U-Th)/He dating  

NASA Astrophysics Data System (ADS)

Deformation of the Magallanes foreland basin and the development and subsequent exhumation of the adjacent fold-and-thrust belt are integral processes that have influenced the modern structure, physiography, and climate of southern Patagonia. Despite recent work documenting these processes, fundamental aspects of the evolution of the Southern Andes remain ambiguous. In this study, apatite (U-Th)/He thermochronology documents the youngest stage in the thermal history of the deformed Magallanes basin. As a regional reconnaissance pilot-study, we conducted replicate, single grain apatite analyses to evaluate the timing and nature of the most recent thrust-related and/or erosional denudation of the dissected fold-thrust belt. Preliminary cooling ages broadly distributed from the Upper Cretaceous to Lower Tertiary Magallanes foreland basin deposits of the Cerro Toro, Tres Pasos, and Dorotea formations near 51 ° S indicate Late Miocene regional cooling through temperatures < ~40 ° C. A sample from the base of the Cerro Toro Formation yields a weighted mean cooling age of 7.55 ± 0.8 Ma. Approximately 40 km north of this locality, the (U-Th)/He cooling age of the overlying Tres Pasos Formation is 8.73 ± 0.81 Ma. Farther east, two samples from the base of the overlying Dorotea Formation document cooling ca. 5.5 Ma. These data document the youngest component of unroofing along the eastern-most part of the fold-and-thrust belt to within ~ 1-1.5 km of the Earth's surface. Here, Neogene shortening is accommodated by gentle folding. Additional thermochronologic constraints are necessary to develop a complete thermal history of these strata, including constraints on cooling rate, magnitude, and exhumational process. To better distinguish between the effects of Miocene thrust-related uplift, erosion, and regional heating on these cooling ages, additional sample coverage using a range of thermochronometers will be employed (specifically, across foreland strata incorporated into the main fold-and-thrust belt). North of this study area, between 44 and 51° S, fission track dating across the Cordillera documents accelerated cooling and denudation at ca. 30 Ma continuing until 12-8 Ma, during which time the location of maximum denudation migrated ~ 200 km eastward (Thomson et al., 2001). These findings, considered with new (U-Th)/He data, motivate the question of how this age-space progression compares to the exhumational history of the fold-and-thrust belt in the Magallanes basin area (~ 51 °S). Further studies of the post-depositional structural and thermal history of the Magallanes basin will clarify the timing of onset and cessation of thrusting, magnitude of shortening, the role of tectonic and erosion-driven denudation, all of which could be compared to the Cenozoic tectonic and climatic history in the northern Patagonian Andes.

Fosdick, J. C.; Romans, B. W.; Hubbard, S. M.

2006-12-01

138

Solid discharge and landslide activity at basin scale  

NASA Astrophysics Data System (ADS)

This work presents a preliminary analysis aimed at understanding the relationship between landslide sediment supply and sediment yield at basin scale in central and southern Italy. A database of solid discharge measurements regarding 116 gauging stations, located along the Apennines chain in Italy, has been compiled by investigating the catalogues, named Annali Idrologici, published by Servizio Idrografico e Mareografico Italiano in the period from 1917 to 1997. The database records several information about the 116 gauging stations, and especially reports the sediment yield monthly measurements (103 ton) and the catchments area (km2). These data have been used to calculate the average solid yield and the normalized solid yield for each station in the observation period. The Italian Landslide Inventory (Progetto IFFI) has been used to obtained the size of the landslides, in order to estimate the landslide mobilization rates. The IFFI Project funded by the Italian Government is realized by ISPRA (Italian National Institute for Environmental Protection and Research - Geological Survey of Italy) in partnership with the 21 Regions and Self Governing Provinces. 21 of the 116 gauging stations and the related catchments have been selected on the basis of the length of the solid discharge observation period and excluding the catchments with dams located upstream the stations. The landslides inside the selected catchments have been extracted from the IFFI inventory, calculating the planimetric area of each landslide. Considering both the shallow and deep landslides, the landslide volume has been estimated using an empirical power law relation (landslide area vs. volume). The total landslide volume in the study areas and the average sediment yield measured at the gauging stations have been compared, analysing the behaviour of the basins which drainage towards the Tyrrhenian sea and the basins which drainage towards the Adriatic sea.

Ardizzone, F.; Guzzetti, F.; Iadanza, C.; Rossi, M.; Spizzichino, D.; Trigila, A.

2012-04-01

139

Catchment classification and model parameter transfer with a view to regionalisation  

NASA Astrophysics Data System (ADS)

Physiographic and climatic catchment characteristics are responsible for catchment response behaviour, whereas hydrological model parameters describe catchment properties in such a way to transform input data (here: precipitation, evaporation) to runoff, hence describing the response behaviour of a catchment. In this respect, model parameters can thus be seen as catchment descriptors. A third catchment descriptor is runoff behaviour, depicted by indices derived from event runoff coefficients and Flow Duration Curves. In an ongoing research project founded by the Deutsche Forschungsgemeinschaft (DFG), we investigate the interdependencies of these three catchment descriptors for catchment classification with a view to regionalisation. The study area comprises about 80 meso-scale catchments in western Germany. These catchments are classified by Self Organising Maps (SOM) based on a) runoff behaviour and b) physical and climatic properties. The two classifications show an overlap of about 80% for all catchments and indicate a direct connection between the two descriptors for a majority of the catchments. Next, all catchments are calibrated with a simple and parsimonious conceptual model, stemming from the Superflex model framework. In this study we test the interdependencies between the classification and the calibrated model parameters by parameter transfer within and between the classes established by SOM. The model simulates total discharge, given observed precipitation and pre-estimated potential evaporation. Simulations with a few catchments show encouraging results: all simulations with the calibrated model show a good fit, which is indicated by Nash Sutcliff coefficients of about 0.8. Most of the simulations of runoff time series for catchments with parameter sets belonging to their own class display good performances too, while simulated runoff with model parameter sets from other classes display significant lower performance. This indicates that there is a strong connection between runoff behaviour, catchment properties and model parameter sets within the classes. The next step is the classification of the catchments based on calibrated model parameters with SOM. If the parameter sets show significant relation to the previous classification, model parameters may be used as an easy accessible start for catchment description. Physiographic and climatic properties can now be related directly to model parameters, corroborating a quantitative approach to basin classification. Furthermore, one representative parameter set for each class of catchments can describe the runoff behaviour for a whole class. The description of runoff behaviour by calibrated model parameters of a conceptual model in relation to classes of physically and climatically similar catchments can facilitates catchment description, classification and regionalisation and provides insight into the processes and functioning of catchments. The use of calibrated model parameters for classification instead of time-consuming description of the runoff behaviour with event runoff coefficients offers an attractive alternative for regionalisation.

Ley, Rita; Hellebrand, Hugo; Casper, Markus C.

2013-04-01

140

Preliminary report on coal resources of the Wyodak-Anderson coal zone, Powder River Basin, Wyoming and Montana  

USGS Publications Warehouse

The National Coal Resource Assessment (NCRA) project by the U.S. Geological Survey is designed to assess US coal with the greatest potential for development in the next 20 to 30 years. Coal in the Wyodak-Anderson (WA) coal zone in the Powder River Basin of Wyoming and Montana is plentiful, clean, and compliant with EPA emissions standards. This coal is considered to be very desirable for development for use in electric power generation. The purpose of this NCRA study was to compile all available data relating to the Wyodak- Anderson coal, correlate the beds that make up the WA coal zone, create digital files pertaining to the study area and the WA coal, and produce a variety of reports on various aspects of the assessed coal unit. This report contains preliminary calculations of coal resources for the WA coal zone and is one of many products of the NCRA study. Coal resource calculations in this report were produced using both public and confidential data from many sources. The data was manipulated using a variety of commercially available software programs and several custom programs. A general description of the steps involved in producing the resource calculations is described in this report.

Ellis, Margaret S.; Gunther, Gregory L.; Flores, Romeo M.; Ochs, Allen M.; Stricker, Gary D.; Roberts, Steven B.; Taber, Thomas T.; Bader, Lisa R.; Schuenemeyer, John H.

1998-01-01

141

Regional climate models for the Carpathian Basin: validation and preliminary results for the future  

NASA Astrophysics Data System (ADS)

Due to their coarse spatial resolution, the results from global climate models (GCM) are not capable to provide detailed regional estimations of future climate conditions. The 10-25 km horizontal resolution regional climate models (RCM) nested into GCMs are expected to improve the regional climate scenarios for the European subregions. Expected regional climate change in the Carpathian basin (located in Central/Eastern Europe) is modelled by four different RCMs. (1) Model PRECIS was developed at the UK Met Office, Hadley Centre. (2) Model RegCM was developed by Giorgi et al., it is available from the ICTP (International Centre for Theoretical Physics). (3) Model REMO was developed by the Max Planck Institute for Meteorology, Hamburg. (4) Model ALADIN/Climate was developed by Météo France on the basis of the internationally developed ALADIN modelling system. The latter one is a spectral model, while the other three RCMs use gridpoint derivatives. The horizontal resolution of the model experiments are 10 km in case of RegCM and ALADIN/Climate, and 25 km in case of PRECIS and REMO. Two of the RCMs (RegCM and PRECIS) are run by the Department of Meteorology, Eötvös Loránd University, Budapest, the other two RCMs are run by the Hungarian Meteorological Service: ALADIN/Climate and REMO. First, control runs of RegCM, PRECIS, REMO and ALADIN are compared for the 1961-1990 period using boundary conditions from the European Centre for Medium-Range Weather Forecast (ECMWF) reanalysis datasets (ERA-40). For the validation, monthly data sets of the Climate Research Unit (CRU) of the University of East Anglia are used. Then, future climate of the Carpathian basin have also been simulated by all RCMs: (1) PRECIS experiments are accomplished for 2071-2100 using A2 and B2 emission scenarios, (2) RegCM and ALADIN/Climate experiments are accomplished for 2021-2050 and 2071-2100 using A1B emission scenario, and (3) REMO experiments are accomplished for 1951-2050 using A1B emission scenario. Results of the future climate simulations are compared and evaluated.

Bartholy, J.; Csima, G.; Horanyi, A.; Hunyady, A.; Pieczka, I.; Pongracz, R.; Szepszo, G.; Torma, C. S.

2009-04-01

142

The relationship between diagenesis and physical properties of sediments in the Shikoku Basin; Preliminary Results  

NASA Astrophysics Data System (ADS)

Integrated Ocean Drilling Program (IODP) Site C0011 is located on the northwest flank of the Kashinosaki Knoll which is the crest of bathymetric high in the Shikoku Basin. In this site, the physical properties of sediment were measured to provide high-resolution data on the bulk physical properties and their downhole variations. All physical property (moisture and density, gamma ray attenuation density, magnetic susceptibility, P-wave velocity, thermal conductivity, vane shear, and electrical resistivity) measurements were made after cores had been imaged by X-ray CT and had equilibrated to room temperature (about 20 °C). From the surface to 50 mbsf, bulk density generally increases and porosity decreases along the downhole. The trend reverses between 50 and 80 mbsf and then remains relatively constant until 240 mbsf. A sharp increase in bulk density (decrease in porosity) occurs between 240 and 270 mbsf, after which a steady consolidation trend continues to the base of the borehole. The dramatic change of physical properties in this section was estimated to be caused by sediment diagenesis which is cementation by the opal-A and opal-CT transformation, because the sediment texture observing from core description and CT scan is unconverted in this section. In the result of sediment texture analysis for total 128 subsamples of Holes C0011C and C0011D, the sediment texture does not show the features related to the change of the physical property between 240 and 270 mbsf, except relatively high mean grain size and sand contents at 235 mbsf. In the quantitative analysis of opal contents for 11 subsamples of Holes C0011C and C0011D, using X-ray diffraction (XRD) and computer software based on Rietveld quantification method, the contents of clay mineral and opal-A are high and also unconverted in all samples, whereas the contents of opal-CT are few. The result of quantitative analysis of opal contents using XRD does not support the sediment diagenesis caused by the opal-A and opal-CT transformation. Therefore, the sediment diagenesis in Site C0011 may not be controlled by the opal-A/opal-CT and opal-CT/quartz transformation and additional study is required to determine the relationship between diagenesis and physical properties of sediments in the Shikoku Basin.

Lee, Gwang Soo; Kim, Gil Young; Kyo Seo, Young; Henry, Pierre; Kanamatsu, Toshiya; Kyaw Thu, Moe; 333 Scientists, Expedition

2013-04-01

143

Reframing water governance: a multi-perspective study of an over-engineered catchment in China  

Microsoft Academic Search

Climate change, over abstraction, pollution and questionable engineering-based paradigms are contributing to a state of crisis in water governance. This paper reports on preliminary research in Lake Baiyangdian catchment, China, which has the potential to realise more systemic and adaptive forms of water governance through development and use of a method that reframes water catchment management in the form of

Yongping Wei; Ray Ison; John Colvin; Kevin Collins

2012-01-01

144

Reframing water governance: a multi-perspective study of an over-engineered catchment in China  

Microsoft Academic Search

Climate change, over abstraction, pollution and questionable engineering-based paradigms are contributing to a state of crisis in water governance. This paper reports on preliminary research in Lake Baiyangdian catchment, China, which has the potential to realise more systemic and adaptive forms of water governance through development and use of a method that reframes water catchment management in the form of

Yongping Wei; Ray Ison; John Colvin; Kevin Collins

2011-01-01

145

A preliminary assessment of sources of nitrate in springwaters, Suwannee River basin, Florida  

USGS Publications Warehouse

A cooperative study between the Suwannee River Water Management District (SRWMD) and the U.S. Geological Survey (USGS) is evaluating sources of nitrate in water from selected springs and zones in the Upper Floridan aquifer in the Suwannee River Basin. A multi-tracer approach, which consists of the analysis of water samples for naturally occurring chemical and isotopic indicators, is being used to better understand sources and chronology of nitrate contamination in the middle Suwannee River region. In July and August 1997, water samples were collected and analyzed from six springs and two wells for major ions, nutrients, and dissolved organic carbon. These water samples also were analyzed for environmental isotopes [18O/16O, D/H, 13C/12C, 15N/14N] to determine sources of water and nitrate. Chlorofluorocarbons (CCl3F, CCl2F2, and C2Cl3F3) and tritium (3H) were analyzed to assess the apparent ages (residence time) of springwaters and water from the Upper Floridan aquifer. Delta 15N-NO3 values in water from the six springs range from 3.94 per mil (Little River Springs) to 8.39 per mil (Lafayette Blue Spring). The range of values indicates that nitrate in the sampled springwaters most likely originates from a mixture of inorganic (fertilizers) and organic (animal wastes) sources, although the higher delta 15N-NO3 value for Lafayette Blue Spring indicates that an organic source of nitrogen is likely at this site. Water samples from the two wells sampled in Lafayette County have high delta 15N-NO3 values of 10.98 and 12.1 per mil, indicating the likelihood of an organic source of nitrate. These two wells are located near dairy and poultry farms, where leachate from animal wastes may contribute nitrate to ground water. Based on analysis of chlorofluorocarbons in ground water, the mean residence time of water in springs ranges from about 12 to 25 years. Chlorofluorocarbons-modeled recharge dates for water samples from the two shallow zones in the Upper Floridan aquifer range from 1985 to 1989.

Katz, B. G.; Hornsby, H. D.

1998-01-01

146

Assessing the differences in sensitivities of runoff to changes in climatic conditions across a large basin  

NASA Astrophysics Data System (ADS)

Budyko curve used to assess runoff sensitivity to changes in climate. Runoff sensitivity assessed spatially across Murray Darling Basin in Australia. Sensitivity assessed spatially for Choudhury's ' n ' parameter. Runoff sensitivity low for whole basin, moderate-high in high-yielding catchments. These few high-yield catchments are critical for strategic basin water management.

Donohue, Randall J.; Roderick, Michael L.; McVicar, Tim R.

2011-09-01

147

Measures of catchment similarity  

NASA Astrophysics Data System (ADS)

Similarity of catchments is often defined on the basis of discharge series. Similarity measures are formulated using dependence measures (such as correlation or empirical copula based variables) relating these series. A major drawback of these approaches is that they can only detect similarity for catchments with the same weather. Further as weather of different time periods is different one would consider the same catchment as dissimilar to itself. The goal of this contribution is to introduce different similarity measures which reflect functional similarity (transformation of precipitation to discharge) and filter out the effects of weather. The alternative similarity measures are defined using: • Flow duration curves • Recession curve behaviour • Bivariate copulas between antecedent precipitation and discharge • Boundary curves of the response dynamics These measures enable the calculation of the self similarity of catchments, providing them reasonable limits and an objective evaluation. The methodology is applied to a large set of US catchments. The usefulness of the similarity measures is tested for the hydrological model HYMOD.

Bárdossy, A.; Huang, Y.; Wagener, T.

2012-04-01

148

Runoff processes, stream water residence times and controlling landscape characteristics in a mesoscale catchment: An initial evaluation  

Microsoft Academic Search

Tracer studies, using Gran alkalinity and ?18O, in nested sub-basins of the 230km2 Feshie catchment in the Cairngorm mountains, Scotland, were used to characterise hydrology in terms of groundwater contributions to annual runoff and mean residence times. Relationships between these fundamental hydrological descriptors and catchment characteristics were explored with the use of a GIS. Catchment soil distribution—mapped by the UK's

C. Soulsby; D. Tetzlaff; P. Rodgers; S. Dunn; S. Waldron

2006-01-01

149

Concentration and mineralogical residence of elements in rich oil shales of the Green River Formation, Piceance Creek basin, Colorado, and the Uinta Basin, Utah - A preliminary report  

USGS Publications Warehouse

Ten samples from drillcore of two rich oil-shale beds from the Parachute Creek Member of the Eocene Green River Formation, Piceance Creek basin, Colorado, and Uinta Basin, Utah, were analyzed for 37 major, minor, and trace elements. For 23 of these elements, principal mineralogical residence is established or suggested and such studies may provide data which are useful for predicting the kinds and amounts of elements and compounds that might be released into the environment by oil-shale mining operations. ?? 1976.

Desborough, G. A.; Pitman, J. K.; Huffman, Jr. , C.

1976-01-01

150

A preliminary assessment of in place coalbed methane resources in the Virginia portion of the central Appalachian Basin  

Microsoft Academic Search

In the central Appalachian basin, Virginia leads in coalbed methane drilling and production, even though it only contains a small fraction of the total coal resources and basin area. In 1992, coalbed methane surpassed conventional and shale gas as Virginia's largest source of natural gas. By the end of 1996 there were 814 wells producing coalbed methane in Virginia. Average

Jack E. Nolde; David Spears

1998-01-01

151

Comparative study of catchment hydrological response and topographic repartition variability. An approach based on field data  

NASA Astrophysics Data System (ADS)

Major stakes major to propose corrective actions with environmental problems would be to have models of simulation. However in the agrosystems, the passage between the field to the catchment is still an unsolved problem. This link runs up against scaling: a hillslope differently behaves from sum of the fields which make it up, a catchment does not always behaves as the juxtaposition of the hillslopes which make it up (Ambroise, 1999). Spatial integration of the data and the scale issues still remain like significant problems for which it always misses a general theory (Beven, 1991; Sivapalan and Kalma, 1995). Like Woods et al. (1995), we decided to explore this problem through observation of many different sizes catchment. The study area is the Sousson catchment (100 km^2, Gers, France). Its "fish-bone" structure allows to sample hydrologically independent catchments. For four campaigns in interstorm period, we collected on the whole 330 instantaneous discharge measurements at catchment's outlets which are temporally comparable by campaign. The relationship between specific and flows catchments area was studied. Two peaks of variability were observed for areas approximately from 1 km^2 and 10 to 20 km^2. This relationship was then compared with characteristics of intra and inter-catchment spatial heterogeneity derived from topography, soil cover and land use. The first peak of hydrological response variability seems to correspond to basins spatially pure and very different from each other (minimal intra-catchment heterogeneity and maximum inter-catchment heterogeneity). The second peak of hydrological response variability does not correspond to notable variations of spatial heterogeneities. These heterogeneity indexes are calculated overall by catchment without taking into account of catchment internal structure. So we may assume that representation of the catchment requires considering the spatial organization when their surface is less than about 10 to 20 km^2. So these ideas open discussions on advisability of using lumped or distributed models according to the spatial scales (Wood, 1995; Kavvas, 1999).

Colin, F.; Raclot, D.; Puech, C.

2003-04-01

152

INTERACTION BETWEEN CLIMATIC CONDITIONS AND WATER POLLUTION: A CASE STUDY FROM THE TRANSBOUNDARY CATCHMENT OF GUADIANA RIVER  

Microsoft Academic Search

The Guadiana catchment is one of the largest basins of the Iberian Peninsula with 66800 km 2 (83% in Spain and 17% in Portugal). Into this catchment, upper and lower Guadiana must be considered in order to their different characteristics, and the lower Guadiana appears in a part of its course as a natural border between Spain and Portugal. Water

Andrés Olay; Nuno Gomes; Rodrigo Álvarez; Sonia Sousa; Jorge Loredo; Marco Antonio Estrela; Cavaco Silva

153

THE EXPERIMENTAL URBAN CATCHMENT \\  

Microsoft Academic Search

An experimental catchment area was set up by the CEREVE in 1996 in the centre of Paris so as to study urban storm water from the atmosphere to the combined sewer's outlet. The distinctive characteristic of this site is its location in a town centre and the extent of the equipment used to monitor the water pollution over the whole

Ghassan Chebbo; Marie-Christine Gromaire; Stéphane Garnaud; Ana Gonzalez

154

Catchment Hydrology and Sustainable Management (CHASM): An Integrating Methodological Framework for Prediction  

NASA Astrophysics Data System (ADS)

New predictive methodologies are needed to support sustainable catchment management, as the EC Water Framework Directive is now upon us and the need for Prediction in Ungauged Basins increases. The CHASM research programme has been established to gain new understanding of the hydrological and ecological functioning of mesoscale catchments (102 - 103 km^2) and of how catchment response changes with scale, and to translate this new knowledge into enhanced predictive capability. In the UK, four mesoscale catchments are being instrumented at the patch/hillslope, micro-catchment (1 km^2) and mini-catchment (10 km^2) scales. A Generic Experimental Design (GED) involving the use of Permanent, Staged and Mobile Instrumentation is being employed to capture the heterogeneity in catchment response across this range of scales. The GED forms part of an Integrating Methodological Framework in which field experimentation and monitoring is linked with landscape classification, modelling and prediction in an iterative cycle in which experimentation is steered by the reduction of predictive uncertainty. The implementation of the CHASM approach on a global network of mesoscale basins would make a significant contribution to underpinning decision making at the catchment (policy) scale.

O Connell, P. E.; Team

2003-04-01

155

Development and Application of a Simple Hydrogeomorphic Model for Headwater Catchments  

EPA Science Inventory

We developed a catchment model based on a hydrogeomorphic concept that simulates discharge from channel-riparian complexes, zero-order basins (ZOB, basins ZB and FA), and hillslopes. Multitank models simulate ZOB and hillslope hydrological response, while kinematic wave models pr...

156

Creating a catchment perspective for river restoration  

NASA Astrophysics Data System (ADS)

One of the major challenges in river restoration is to identify the natural fluvial landscape in catchments with a long history of river control. Intensive land use on valley floors often predates the earliest remote sensing: levees, dikes, dams, and other structures alter valley-floor morphology, river channels and flow regimes. Consequently, morphological patterns indicative of the fluvial landscape including multiple channels, extensive floodplains, wetlands, and fluvial-riparian and tributary-confluence dynamics can be obscured, and information to develop appropriate and cost effective river restoration strategies can be unavailable. This is the case in the Pas River catchment in northern Spain (650 km2), in which land use and development have obscured the natural fluvial landscape in many parts of the basin. To address this issue we coupled general principles of hydro-geomorphic processes with computer tools to characterize the fluvial landscape. Using a 5-m digital elevation model, valley-floor surfaces were mapped according to elevation above the channel and proximity to key geomorphic processes. The predicted fluvial landscape is patchily distributed according to topography, valley morphology, river network structure, and fan and terrace landforms. The vast majority of the fluvial landscape in the main segments of the Pas River catchment is presently masked by human infrastructure, with only 15% not impacted by river control structures and development. The reconstructed fluvial landscape provides a catchment scale context to support restoration planning, in which areas of potential ecological productivity and diversity could be targeted for in-channel, floodplain and riparian restoration projects.

Benda, L.; Miller, D.; Barquín, J.

2011-03-01

157

Preliminary Study of Uranium Favorability of Upper Cretaceous, Paleocene, and Lower Eocene Rocks of the Bighorn Basin, Wyoming and Montana.  

National Technical Information Service (NTIS)

This report presents an evaluation of the uranium favorability of continental sediments of the Upper Cretaceous Lance, Paleocene Polecat Bench, and lower Eocene Willwood Formations in the Bighorn Basin of Wyoming and Montana, an intermontane structural ba...

J. F. Dunagan S. L. Hesse

1978-01-01

158

Nutrient loads exported from managed catchments reveal emergent biogeochemical stationarity  

NASA Astrophysics Data System (ADS)

Complexity of heterogeneous catchments poses challenges in predicting biogeochemical responses to human alterations and stochastic hydro-climatic drivers. Human interferences and climate change may have contributed to the demise of hydrologic stationarity, but our synthesis of a large body of observational data suggests that anthropogenic impacts have also resulted in the emergence of effective biogeochemical stationarity in managed catchments. Long-term monitoring data from the Mississippi-Atchafalaya River Basin (MARB) and the Baltic Sea Drainage Basin (BSDB) reveal that inter-annual variations in loads (LT) for total-N (TN) and total-P (TP), exported from a catchment are dominantly controlled by discharge (QT) leading inevitably to temporal invariance of the annual, flow-weighted concentration, $\\overline{Cf = (LT/QT). Emergence of this consistent pattern across diverse managed catchments is attributed to the anthropogenic legacy of accumulated nutrient sources generating memory, similar to ubiquitously present sources for geogenic constituents that also exhibit a linear LT-QT relationship. These responses are characteristic of transport-limited systems. In contrast, in the absence of legacy sources in less-managed catchments, $\\overline{Cf values were highly variable and supply limited. We offer a theoretical explanation for the observed patterns at the event scale, and extend it to consider the stochastic nature of rainfall/flow patterns at annual scales. Our analysis suggests that: (1) expected inter-annual variations in LT can be robustly predicted given discharge variations arising from hydro-climatic or anthropogenic forcing, and (2) water-quality problems in receiving inland and coastal waters would persist until the accumulated storages of nutrients have been substantially depleted. The finding has notable implications on catchment management to mitigate adverse water-quality impacts, and on acceleration of global biogeochemical cycles.

Basu, Nandita B.; Destouni, Georgia; Jawitz, James W.; Thompson, Sally E.; Loukinova, Natalia V.; Darracq, Amélie; Zanardo, Stefano; Yaeger, Mary; Sivapalan, Murugesu; Rinaldo, Andrea; Rao, P. Suresh C.

2010-12-01

159

Projecting Changes in Catchment Water Availability using a Budyko Framework (Invited)  

NASA Astrophysics Data System (ADS)

Making predictions about the future is always fraught with difficulty. Predictions about future water availability are no exception. To be credible, predictions have to consider possible changes in both climate and catchment characteristics. In this paper, we show how the well known Budyko theory of the catchment water balance can be adapted to derive predictions about changes in water availability as a function of changes in both climate and catchment properties. The power of the theoretical framework is demonstrated using the Murray-Darling Basin in southeast Australia as a case study.

Roderick, M. L.; Farquhar, G. D.

2009-12-01

160

Testing the Variable Source Area Hypothesis Using Tracers and GIS in an Nested Mesoscale Catchment  

NASA Astrophysics Data System (ADS)

Hydrometric and natural tracer investigations were combined with a GIS analysis of the 31km2 Girnock catchment (Cairngorm National Park, Scotland), to assess the significance of the variable source areas model in explaining dominant runoff process and mean residence times within the catchment. The catchment has a complex geology, soil cover and topographic organisation. Gran alkalinity was used to demonstrate that catchment geology has a dominant influence on baseflow chemistry, but low storm flow alkalinity indicated that flow paths originating in the acidic horizons in the upper profile of catchment soils dominated storm runoff generation. Chemically-based hydrograph separations at the catchment scale indicated that around 70% of annual runoff was derived from surface and near surface hydrological sources. Similar contributions (64-77%) were estimated for virtually all major sub-basins. delta18O ratios in precipitation (mean: -9.36, range: -16.10 to -5.02) and streamwaters (mean: -9.11, range: -11.65 to -7.42) were used to assess mean catchment and sub-basin residence times which were consistently in the order of 4-6 months. GIS analysis showed that these tracer-based diagnostic features of catchment functioning were consistent with the landscape organisation of the catchment. Soil maps derived from the UK HOST (Hydrology of Soil Type) data base indicated that the catchment as a whole, and individual sub-basins, were dominated by responsive soils such as Histosols and gleysols in valley bottom areas. Spatial analysis of soil cover - in combination with a catchment topographic index - predicted extensive areas of saturation in valley bottom areas that expand during hydrological events from return flow of hillslope groundwaters and direct precipitation generating saturation overland flow. Thus during storm events, a variable source area model agrees well with the high degree of hydrological connectivity between catchment hillslopes and the stream channel network. However, groundwater re-charge in the catchment is complex and characterised by much more marked heterogeneity than implied by the variable source area concept.

Tetzlaff, D.; Soulsby, C.; Waldron, S.; Malcolm, I.; Dunn, S.; Lilly, A.

2005-12-01

161

Catchment classification based on characterisation of streamflow and precipitation time-series, Part II: Application to ungauged catchments  

NASA Astrophysics Data System (ADS)

One of the primary practical objectives for delineating hydrological homogeneous regions is to assess the membership of ungauged sites, thus inferring indications on the response behaviour of such catchments. An important feature of a cluster analysis aimed at identifying homogeneous clusters is therefore the ability to discriminate between them on the basis of variables that are different from the streamflow signatures, that is, a set of physical and climatic characteristics of the watersheds. The first part of the study (companion presentation: Part I: Classification of streamflow signatures) illustrates a SOM-based approach for catchment grouping on the basis of their hydrological response, through a representation, albeit simplified, of the properties of fine time-scale flow series and in particular of the dynamic components of the hydrometric data. In order to assign ungauged sites to such groups, the catchments are here represented through a parsimonious set of morphometric and pluviometric variables, including also indexes that attempt to synthesize the variability and correlation properties of the precipitation time-series, thus providing information on the type of weather forcing that is specific to each basin. Following a principal components analysis, needed for synthesizing and better understanding the morpho-pluviometric catchment properties, a Discriminant Analysis finally classifies the ungauged catchments, through a leave-one-out cross-validation, to one of the above identified hydrologic response classes. The approach delivers quite satisfactory results for ungauged catchments, since the comparison of the two cluster sets shows an acceptable overlap. Overall results indicate that the inclusion of information on the properties of the fine time-scale streamflow and rainfall time-series may be a promising way for better representing the hydrologic and climatic character of the study catchments.

Toth, Elena

2013-04-01

162

Hydrological Catchment Similarity Assessment in Geum River Catchments, Korea  

NASA Astrophysics Data System (ADS)

Similarity measure of catchments is essential for regionalization studies, which provide in depth analysis in hydrological response and flood estimations at ungauged catchments. However, this similarity measure is often biased to the selected catchments and is notclearly explained in hydrological sense. This study applied a type of hydrological similarity distance measure-Flood Estimation Handbook to 25 Geum river catchments, Korea. Three Catchment Characteristics, Area (A)-Annual precipitation (SAAR)-SCS Curve Number (CN), are used in Euclidian distance measures. Furthermore, six index of Flow Duration Curve (ILow:Q275/Q185, IDrought:Q355/Q185, IFlood:Qmax/Q185, IAbundant:Q95/Q185, IFloodDuration:Q10/Q355 and IRiverRegime:Qmax/Qmin) are applied to clustering analysis of SPSS. The catchments' grouping of hydrological similarity measures suggests three groups: H1 (Cheongseong, Gidae, Bukil, Oksan, Seockhwa, Habgang and Sangyeogyo), H2 (Cheongju, Guryong, Ugon, Boksu, Useong and Seokdong) and H3 (Muju, Yangganggyo and YongdamDam). The four catchments (Cheoncheon, Donghyang, DaecheongDam and Indong) are not grouped in this study. The clustering analysis of FDC provides four Groups; CFDC1 (Muju, YongdamDam, Yangganggyo, DaecheongDam, Cheongseong, Gidae, Seokhwa, Bukil, Habgang, Cheongju, Oksan, Yuseong and Guryong), CFDC2 (Cheoncheon, Donghyang, Boksu, Indong, Nonsan, Seokdong, Ugon, Simcheon, Useong and Sangyeogyo), CFDC3 (Songcheon) and CFDC4 (Tanbu). The six catchments (out of seven) of H1 are grouped in CFDC1, while Sangyeogyo is grouped in CFDC2. The four catchments (out of six) of H2 are also grouped in CFDC2, while Cheongju and Guryong are grouped in CFDC1. The catchments of H3 are categorized in CFDC1. The authors examine the results (H1, H2 and H3) of similarity measure based on catchment physical descriptors with results (CFDC1 and CFDC2) of clustering based on catchment hydrological response. The results of hydrological similarity measures are supported by clustering analysis of FDC. This study shows a potential of hydrological catchment similarity measures in Korea. It will be used as a starting point for flood predictions at ungauged catchment.

Ko, Ara; Park, Kisoon; Lee, Hyosang

2013-04-01

163

Geochemical signature and properties of sediment sources and alluvial sediments within the Lago Paranoá catchment, Brasilia DF: a study on anthropogenic introduced chemical elements in an urban river basin.  

PubMed

One of the largest urban agglomerations in Brazil is the capital Brasilia and its surrounding area. Due to fast urban sprawl and accelerated land use changes, available water supplies are near their limits. The water supply depends largely on surface water collected in reservoirs. There are increasing concerns regarding water shortages due to sediment aggradations, and of water quality due to geochemical modification of sediments from human activities. The concentration of 18 chemical elements and five sediment properties was analyzed from different potential land-based sediment sources and deposited alluvial sediment within the Lago Paranoà catchment. The goal of this study was to assess the distribution of chemical elements and geochemical/physical properties of potential sediment sources in the Lago Paranoá catchment. Principal component analysis and hierarchical cluster analysis were used to investigate the influence of different land use types on the geochemistry of sediments. Geochemical fingerprints of anthropogenic activities were developed based on the results of the cluster analysis grouping. The anthropogenic input of land use specific geochemical elements was examined and quantified by the calculation of enrichment factors using the local geological background as reference. Through comparison of the geochemical signature of potential sediment sources and alluvial sediments of the Lago Paranoá and sub-catchments, the relative contribution of land use specific sediment sources to the sediment deposition of the main water reservoir were estimated. The existing findings suggest a strong relationship between land use and quantifiable features of sediment geochemistry and indicate that urban land use had the greatest responsibility for recent silting in the Lago Paranoá. This assessment helps to characterize the role of human activities in mixed-used watersheds on sediment properties, and provides essential information to guide management responses towards more effective source-reduction strategies. PMID:23542435

Franz, C; Makeschin, F; Weiß, H; Lorz, C

2013-03-27

164

Uncertainty analysis in model parameters regionalization: a case study involving the SWAT model in Mediterranean catchments (Southern France)  

NASA Astrophysics Data System (ADS)

In this study a method for propagating the hydrological model uncertainty in discharge predictions of ungauged Mediterranean catchments using a model parameter regionalization approach is presented. The method is developed and tested for the Thau catchment located in southern France using the SWAT hydrological model. Regionalization of model parameters based on physical similarity measured between gauged and ungauged catchments attributes is a popular methodology for discharge prediction in ungauged basins, but it is often confronted with an arbitrary criterion for selecting the "behavioral" model parameters sets (Mps) at the gauged catchment. A more objective method is provided in this paper where the transferrable Mps are selected based on the similarity between the donor and the receptor catchments. In addition, the method allows propagating the modeling uncertainty while transferring the Mps to the ungauged catchments. Results indicate that physically similar catchments located within the same geographic and climatic region may exhibit similar hydrological behavior and can also be affected by similar model prediction uncertainty. Furthermore, the results suggest that model prediction uncertainty at the ungauged catchment increases as the dissimilarity between the donor and the receptor catchments increases. The methodology presented in this paper can be replicated and used in regionalization of any hydrological model parameters for estimating streamflow at ungauged catchment.

Sellami, H.; La Jeunesse, I.; Benabdallah, S.; Baghdadi, N.; Vanclooster, M.

2013-04-01

165

Modelling sources of sediment at sub-catchment scale: An example from the Burdekin catchment, North Queensland, Australia  

Microsoft Academic Search

A detailed sediment budget has been derived for the Weany Creek sub-catchment (13.5km2) in North Queensland, Australia, using a sediment source, transport and depositional model known as SedNet (I. Prosser, P. Rustomji, W. Young, C. Moran, A. Hughes, CSIRO Land and Water Technical Report 15\\/01, Constructing River Basin Sediment Budgets for the National Land and Water Resources Audit, 2001, http:\\/\\/www.clw.csiro.au\\/publications\\/technical2001\\/tr15-01.pdf.).

Anne E. Kinsey-henderson; David A. Post; Ian P. Prosser

2005-01-01

166

Environmental care in agricultural catchments: Toward the communicative catchment  

NASA Astrophysics Data System (ADS)

Substantial land degradation of agricultural catchments in Australia has resulted from the importation of European farming methods and the large-scale clearing of land. Rural communities are now being encouraged by government to take responsibility for environmental care. The importance of community involvement is supported by the view that environmental problems are a function of interactions between people and their environment. It is suggested that the commonly held view that community groups cannot care for their resources is due to inappropriate social institutions rather that any inherent disability in people. The communicative catchment is developed as a vision for environmental care into the future. This concept emerges from a critique of resource management through the catchment metaphors of the reduced, mechanical, and the complex, evolving catchment, which reflect the development of systemic and people-centered approaches to environmental care. The communicative catchment is one where both community and resource managers participate collaboratively in environmental care. A methodology based on action research and systemic thinking (systemic action research) is proposed as a way of moving towards the communicative catchment of the future. Action research is a way of taking action in organizations and communities that is participative and informed by theory, while systemic thinking takes into account the interconnections and relationships between social and natural worlds. The proposed vision, methodology, and practical operating principles stem from involvement in an action research project looking at extension strategies for the implementation of total catchment management in the Hunter Valley, New South Wales.

Martin, Peter

1991-11-01

167

Exhumation of the Magallanes foreland basin, Patagonian Andes, Chile (51 °S): Preliminary results from apatite (U-Th)\\/He dating  

Microsoft Academic Search

Deformation of the Magallanes foreland basin and the development and subsequent exhumation of the adjacent fold-and-thrust belt are integral processes that have influenced the modern structure, physiography, and climate of southern Patagonia. Despite recent work documenting these processes, fundamental aspects of the evolution of the Southern Andes remain ambiguous. In this study, apatite (U-Th)\\/He thermochronology documents the youngest stage in

J. C. Fosdick; B. W. Romans; S. M. Hubbard

2006-01-01

168

Devonian Shelf to Basin Facies Distributions and Preliminary Shale Geochemistry for South-central and Southwestern New Mexico  

Microsoft Academic Search

The often poorly exposed Devonian section in southern New Mexico contains complex vertical and lateral ramp-to-basin facies changes that culminate in an elongate trough filled with up to 76 m of black shale. The trough trends east-west for over 350 km, and ranges from a width of ~30 km near Las Cruces to ~100 km near Deming. To the north,

William D. Raatz

169

Preliminary results comparing DHSVM and Sacramento Model simulations versus observed flows in the Cheat River Basin, WV  

NASA Astrophysics Data System (ADS)

The National Weather Service (NWS) Ohio River Forecast Center (OHRFC) has calibrated the Sacramento Soil Moisture Accounting (SAC-SMA) Model to approximately 100 subbasins in the Ohio River Basin for use in current daily operations. Many additional calibrations are expected to be completed in the coming months. However, research is also underway to evaluate the use of a fully distributed hydrologic model, the Distributed Hydrologic Soil-Vegetation Model (DHSVM), developed at the University of Washington. DHSVM has been implemented for the Cheat River Basin, a high terrain region of West Virginia, that experiences significant snowfall and orographically driven precipitation enhancement. Model simulation comparisons between the SAC-SMA model and DHSVM against observed flows will be presented. Distributed hydrologic models have long promised improvements over lumped conceptual models such as the SAC-SMA. Geographic Information Systems (GIS) combined with significant improvements in both the quantity and quality of soils, vegetation, terrain, landuse, and other geophysical data sets have made it feasible to objectively estimate model parameters for hydrologic models over broad areas, namely, the Ohio River Basin. The more physically-based hydrologic models become, the more quickly these models can be implemented and the more easily their model states can be interpreted and compared to remotely sensed observations, while minimizing subjective model calibrations. An additional benefit of the use of physically-based distributed hydrologic models, like DHSVM, is the capability of interfacing with atmospheric numerical weather prediction (NWP) models through their land-surface parameterizations.

Adams, T. E.

2001-05-01

170

Preliminary assessment of climatic change during late Wisconsin time, southern Great Basin and vicinity, Arizona, California, and Nevada  

SciTech Connect

Concentration and relative abundance of plant macrofossils illustrate compositional variations in samples from the Eleana Range-2 packrat midden. Nine macrofossil assemblages spanning 6500 radiocarbon years record local vegetational changes in the southern Great Basin of Nevada during the last one-half of the late Wisconsin glacial age. The vegetation of the Eleana Range-2 site, on a south-facing slope at 1810 meters altitude, was characterized by limber pine and steppe shrubs, from before 17,100 radiocarbon years before present to shortly after 13,200 radiocarbon years before present. Changes toward a more xerophytic plant association at the site began by 16,000 radiocarbon years before present, culminating in a major change to pinyon-juniper woodland between 13,200 and 11,700 radiocarbon years before present. The climatic reconstruction for the late full glacial episode (17,000 to 15,000 radiocarbon years before present) that is proposed to account for limber pine-shrub vegetation in the Eleana Range is characterized by increased winter precipitation, and very little summer rainfall. A major warming trend occurred between about 16,000 and 12,000 radiocarbon years before present and was largely concordant with major dessication of closed lakes in the southern Great Basin. A period of wetter conditions in the southern Great Basin during the latest Wisconsin may have incorporated increased precipitation during both the summer and winter, and lower temperatures during the winter, relative to the present. 93 references, 5 figures, 6 tables.

Spaulding, W.G.; Robinson, S.W.; Paillet, L.

1984-12-31

171

Temporal buffering of climate-driven sediment flux cycles by transient catchment response  

NASA Astrophysics Data System (ADS)

The marine sedimentary record can exhibit a systematic cyclicity that is consistent with climate variability driven by Milankovitch-scale forcing. Milankovitch-band cyclicity is widely interpreted in the hemipelagic and pelagic sediments of the marine realm, and in terrestrial paleoenvironments has been observed in lacustrine sediments, soils and river floodplain successions. It remains unclear, however, if and how mountain catchments, as a primary sediment source, respond to these high frequency (<106 yr) climatic cycles, and whether particulate sediment flux signals can be expected to be recorded in the clastic sedimentary record of adjacent basin-fills. Recent field and theoretical studies suggest that mountain catchments respond transiently to high frequency forcing, and so sediment discharge from the catchment is a non-linear function of forcing variables. Using a catchment-basin model, we demonstrate that climate-driven cyclicity in particulate sediment discharge is strongly damped when the period of climate variability is shorter than the response timescale of the eroding landscape. Given that the response timescale of landscapes is of the order of 106 yr, and that Milankovitch-driven climate cyclicity is of the order of 104-105 yr, it is likely that climate-driven perturbation of upland catchments at these periods will be strongly damped by transient landscape behaviour. Our results therefore suggest that stratigraphy built by particulate fluxes from upland catchments, and long-term trends in the sediment delivery to the ocean, may be relatively insensitive to short-term climate variability.

Armitage, John J.; Dunkley Jones, Tom; Duller, Robert A.; Whittaker, Alexander C.; Allen, Philip A.

2013-05-01

172

Decision Support System for Catawba River Basin  

Microsoft Academic Search

WARMF (Watershed Analysis Risk Management Framework) was developed as a decision support system for the entire 12,330 km2 (~5,000 mile2) Catawba River Basin of North and South Carolina. The watershed is divided into a network of land catchments, stream segments, and stratified lakes. WARMF applies daily meteorology data to land catchments to simulate runoff and nonpoint loads. The nonpoint loads

Laura H. Z. Weintraub; Larry Olmsted; Carl W. Chen; Robert Goldstein; Gene Vaughan; Steve Johnson; Ty Ziegler; Bill Foris; Andy Brown; Doug Besler; Dave Braatz

2001-01-01

173

Exploring the link between spatial hydrologic variability and catchment similarity for the purpose of regionalisation  

NASA Astrophysics Data System (ADS)

Catchments are complex systems, with a large number of strongly interdependent variables operating at many space and time scales. This makes it difficult to discover the processes in a particular catchment in greater detail as a prerequisite for runoff modelling. Instead of studying a particular catchment in much detail, we can explore spatial patterns of the runoff response to learn about the most important runoff generating processes in a study area. This can be done by linking the spatial variability of runoff signatures with that of climate and catchment characteristics through statistical techniques. The gained additional knowledge about catchment functioning can then be the departure for improved regionalisation models, which enable more reliable estimates at ungauged basins than models which do not take process information into account. This contribution explores the link between representations of hydrological variability and catchment similarity measures for the purpose of regionalisation. Guided by case studies of an Austrian and a German study area, we show how spatial patterns of the various runoff signatures, from droughts to floods, together with representations of climate and catchment characteristics can be jointly used to infer catchment functioning in terms of most important runoff generating processes. It is further shown how the information about similarly and differently functioning catchments can be employed to improve statistical regionalisation models. Results indicate that for seasonal climates, low flow processes are strongly linked with seasonality patterns. Grouping catchments according to seasonality can therefore significantly improve the predictive performance of regionalisation. The German study showed that shape and magnitude of the annual flood distributions are linked (i) to different catchment/climate characteristics (ii) in different (linear/non-linear) ways. This suggested a combined model of Top-kriging (linear model for flood magnitude) with the Index Flood method (non-linear model for flood shape) as suitable regionalisation method. A cross-validation analysis showed that the combined model performed indeed better than alternative statistical models which did not take process information into account. We conclude that the spatial patterns of runoff signatures, together with those of climate and catchment characteristics, contain a wealth of information, which can be profitably used for runoff predictions in ungauged basins.

Laaha, Gregor; Salinas, Jose L.; Blöschl, Günter

2013-04-01

174

Structure of the Palomares margin from preliminary results of the TOPOMED-GASSIS seismic survey (Algero-Balearic basin, Western Mediterranean)  

NASA Astrophysics Data System (ADS)

We present two deep seismic reflection lines acquired during the TOPOMED-GASSIS seismic survey across the Palomares margin at the northwestern side of the Algero-Balearic basin. Simultaneously 3.5 kHz multi parametric echo-sounder profiles and bathymetric data were acquired, in order to obtain information of the most recent sedimentary/tectonic records, to relate tectonic structure with seafloor features and find out a possible tectonic control on them. The deep seismic reflection and the 3.5 kHz multi parametric echo-sounder profiles evidence anticlines and synclines affecting the Quaternary sediments. The southeastern limbs of the anticlines are cut by reverse faults suggesting a fault propagation origin for the folds. The recent to present character of these structures is confirmed by the congruence between structural and bathymetric highs and lows. Indeed, the submarine channels that cut across the margin are deflected by the folds flowing parallel to the major synclines, although cutting and incising into one of the anticlines. The folds have a N40-50°E orientation oblique to the Palomares active N20°E sinistral strike-slip fault zone. The data obtained from the TOPOMED-GASSIS seismic survey highlight the presence of contractive structures along the Palomares margin oriented perpendicular to the present NW-SE shortening stress field and according with the present GPS geodetic displacements. This preliminary result depicts a contractive Palomares margin where NW-SE shortening is accommodated by Quaternary NE-SW folds and thrusts. In the coastline and on land the shortening is also accommodated by reverse faults that cut both limbs of the Sierra Cabrera anticline. These faults and folds accommodate the sinistral displacement of the more northerly striking Palomares fault zone. Thus, the Palomares fault zone probably terminates close to the coast line to the south of the Vera basin by merging into these more northeasterly oriented structures. These folds probably nucleated upon previous extensional tilted blocks formed during the late Miocene development of the Algero-Balearic basin.

Giaconia, F.; Guzman Vendrell, M.; Booth-Rea, G.; Ranero, C. R.; Grácia, E.; Lo Iacono, C.

2012-04-01

175

Towards Estimating the Nutrient Balance of the Hydrologic Open Air Laboratory (HOAL) Catchment, Lower Austria  

NASA Astrophysics Data System (ADS)

The fate of nutrients introduced by human activities have significant impacts on both nature and our civilization. Excessive nutrients can contaminate our drinking water as well as promote algae blooms that deplete the surrounding waters of oxygen for aquatic life. It is estimated that agriculture in Austria contributes approximately 60% to the total discharge of nitrogen and 40% to the total discharge of phosphorus. Understanding the specific pathways and sources of nitrogen and phosphorus from agriculture land could greatly improve our ability to mitigate for excessive discharges if the problems can be targeted more precisely. The objective of our research is to determine the complete nitrogen and phosphorous balance within a 66.7 hectare catchment in Lower Austria. The Hydrologic Open Air Laboratory (HOAL) catchment is located in Lower Austria approximately 100 km west of Vienna. The HOAL catchment was established in 2009 through funding by the Austrian Science Foundation to be used for multidisciplinary hydrologic research for understanding water flow and transport processes in catchments. The catchment land cover is characterized as 90% agriculture, 5% impermeable surface, and 3% forest. The predominant soil type is a clayey silt loam and a section of the catchment contain a subsurface tile drainage network that extend approximately 5.5 km. Nitrogen and phosphorus are the two primary nutrients assessed in this study. To accomplish the nutrient balance, the research is divided into three different scales: Field Scale, Subcatchment Scale, and Catchment Scale. The Catchment scale encompasses the entirety of the catchment, the subcatchment scale encompasses a 6.4 hectare area within the catchment that is completely underlain by the tile drainage network, and the field scale studies are performed on several square meter plots within the subcatchment. Each scale attempts to determine different parts of the total nutrient budget. The initial phase of the research focused on the identification of the magnitude of the contributing sources of nutrients within the catchment. Water quality data from the catchment outlet have been assessed and preliminary estimates of the spatial and temporal nature of the nutrient pathways have been determined. With estimates of source contribution, we have devised methodologies at every scale within the catchment to accurately estimate the nutrient fluxes and techniques to upscale from the field scale to the catchment scale.

Exner-Kittridge, Michael; Zessner, Matthias; Broer, Martine; Eder, Alexander; Strauss, Peter; Blöschl, Günter

2010-05-01

176

Inferences from a catchment-scale tracer circulation experiment  

NASA Astrophysics Data System (ADS)

The coherent description of water flow and solute transport within heterogeneous hydrologic media typically involved at basin scales in response to external rainfall forcings represents a challenge in hydrological modeling. The mechanisms determining the mobilization and transport of solutes in soils through the paths of runoff formation are investigated by analyzing the results of a tracer experiment conducted within an instrumented hillslope draining into a tributary of the Dese river basin (North-eastern Italy). The response of the test catchment has been analyzed by employing two different chemical tracers: nitrates from diffuse agricultural sources (NO3-) and lithium from a point injection (Li+). Rainfall depths, streamflows and pressure heads within different soil horizons have been suitably measured. Inferences from the modeling exercise simulating the observed hydro-chemical response are discussed. Comparative analyses prove instructive, in particular concerning issues on the age of runoff water, an issue that is central to our current understanding of the mechanisms of transport at basin scale.

Rinaldo, A.; Botter, G.; Bertuzzo, E.; Marani, M.

2008-12-01

177

Phosphorus and nitrate run?off in hill pasture and forest catchments, Taita, New Zealand  

Microsoft Academic Search

Phosphorus and nitrogen were measured in stream run?off from the four catchments of the Taita Experimental Basin (41° 11? S, 174° 58? E). The land is used as exotic conifer forest, native forest, and hill pasture. Multiple regression analysis was used to estimate chemical losses per unit area in floods and at low flows.At low flows, the hill pasture (fertilised

R. H. S. McColl; E. White; A. R. Gibson

1977-01-01

178

Microbial water pollution: A screening tool for initial catchment-scale assessment and source apportionment  

Microsoft Academic Search

The European Union Water Framework Directive requires that Management Plans are developed for individual River Basin Districts. From the point of view of faecal indicator organisms (FIOs), there is a critical need for screening tools that can provide a rapid assessment of the likely FIO concentrations and fluxes within catchments under base- and high-flow conditions, and of the balance (‘source

D. Kay; S. Anthony; J. Crowther; B. J. Chambers; F. A. Nicholson; D. Chadwick; C. M. Stapleton; M. D. Wyer

2010-01-01

179

COMMENTS ON THE CATCHMENT EXPERIMENT TO DETERMINE VEGETAL EFFECTS ON WATER YIELD1  

Microsoft Academic Search

So far most applicable knowledge about forests and water yield has come from catch- ment experiments. Perhaps even more practical information might have been secured during the past twenty years if more and better designed catchment experiments had been undertaken. At the very least, the old question of the main effects of vegetation on total basin water yield should now

John D. Hewlett

180

Functional streamflow disaggregation: Performance for headwater catchments from lowlands to alpine  

Microsoft Academic Search

The performance is demonstrated and evaluated, for headwater catchments across Central Europe, of the recently published Functional Streamflow Disaggregation (FSD) technique. To this end, some 16 gauging stations have been selected from river basins of the upper Danube (Southern Germany), the Danube tributary Ybbs (Central Austria), and the Elbe (German part). Independent simulations were available using three different distributed hydrologic

P. Carl; K. Gerlinger; F. F. Hattermann; V. Krysanova; C. Schilling; H. Behrendt

2009-01-01

181

Future climate scenarios and rainfall–runoff modelling in the Upper Gallego catchment (Spain)  

Microsoft Academic Search

Global climate change may have large impacts on water supplies, drought or flood frequencies and magnitudes in local and regional hydrologic systems. Water authorities therefore rely on computer models for quantitative impact prediction. In this study we present kernel-based learning machine river flow models for the Upper Gallego catchment of the Ebro basin. Different learning machines were calibrated using daily

C. M. Bürger; O. Kolditz; H. J. Fowler; S. Blenkinsop

2007-01-01

182

Snowmelt in a High Latitude Mountain Catchment: Effect of Vegetation Cover and Elevation  

Microsoft Academic Search

The energetics and mass balance of snowpacks in the premelt and melt period were compared from three elevation bands in a high latitude mountain catchment, Wolf Creek Research Basin, Yukon. Elevation is strongly correlated with vegetation cover and in this case the three elevation bands (low, middle, high) correspond to mature spruce forest, dense shrub tundra and sparse tundra (alpine).

J. W. Pomeroy; R. L. Essery; C. R. Ellis; N. R. Hedstrom; R. Janowicz; R. J. Granger

2004-01-01

183

The role of topography on catchment-scale water residence time  

NASA Astrophysics Data System (ADS)

The age, or residence time, of water is a fundamental descriptor of catchment hydrology, revealing information about the storage, flow pathways, and source of water in a single integrated measure. While there has been tremendous recent interest in residence time estimation to characterize watersheds, there are relatively few studies that have quantified residence time at the watershed scale, and fewer still that have extended those results beyond single catchments to larger landscape scales. We examined topographic controls on residence time for seven catchments (0.085-62.4 km2) that represent diverse geologic and geomorphic conditions in the western Cascade Mountains of Oregon. Our primary objective was to determine the dominant physical controls on catchment-scale water residence time and specifically test the hypothesis that residence time is related to the size of the basin. Residence times were estimated by simple convolution models that described the transfer of precipitation isotopic composition to the stream network. We found that base flow mean residence times for exponential distributions ranged from 0.8 to 3.3 years. Mean residence time showed no correlation to basin area (r2 < 0.01) but instead was correlated (r2 = 0.91) to catchment terrain indices representing the flow path distance and flow path gradient to the stream network. These results illustrate that landscape organization (i.e., topography) rather than basin area controls catchment-scale transport. Results from this study may provide a framework for describing scale-invariant transport across climatic and geologic conditions, whereby the internal form and structure of the basin defines the first-order control on base flow residence time.

McGuire, K. J.; McDonnell, J. J.; Weiler, M.; Kendall, C.; McGlynn, B. L.; Welker, J. M.; Seibert, J.

2005-05-01

184

Spatial and temporal patterns of off-slope sediment delivery for small catchments subject to shallow landslides within the Waipaoa catchment, New Zealand  

NASA Astrophysics Data System (ADS)

The Waipaoa catchment in New Zealand has one of the highest measured specific suspended sediment yields measured in New Zealand compared to basins of comparable size. A significant source of this sediment is from shallow landslides which are often triggered on a regional scale during large magnitude storm events, defined as ~ 200 mm rainfall within 72 h. The first step of this sediment cascade is removal of landslide material from the slope and into the fluvial system when the debris tail is in physical contact and hence considered connected. The difference between the volume of sediment liberated in the event and the volume remaining on the slope immediately following the event is termed the off-slope sediment delivery ratio. This value ranged from 0.12 to 0.28 for small sub-catchments within the Waipaoa catchment depending on catchment morphology, landslide and triggering event characteristics. In the Waipaoa catchment a decrease in the catchment sediment delivery ratio is observed as the sub-catchment size increased. A human induced process which may affect off-slope sediment delivery is regolith exhaustion, as scars move further upslope in response to removal of preferred weathered material during previous events on the lower sections of slope. However, it appears that temporal scar migration away from the channels is not prevalent. Therefore, the hypothesis that hillslope relaxation since deforestation is prevalent in this setting is considered null. Rather the temporal pattern to sediment delivery ratios supports the context of evolving catchment in response to deforestation in the Terrain Event Resistance Model.

Jones, Katie E.; Preston, Nicholas J.

2012-03-01

185

Contaminated soil and sediments in a highly developed catchment-estuary system (Sydney estuary, Australia): an innovative stormwater remediation strategy  

Microsoft Academic Search

Purpose  The objective of the current research was to provide a strategy to remediate stormwater from an old, high-developed catchment\\u000a dominated (94%) by diffuse sources. Contaminated catchment soils, a dense road network and extensive residential development\\u000a have resulted in degraded sediments in the receiving basin. Retrofitting stormwater remedial devices in such catchment-estuarine\\u000a systems is difficult, costly and long term.\\u000a \\u000a \\u000a \\u000a \\u000a Materials and

Gavin F. Birch

2011-01-01

186

The large-scale landslide risk classification in catchment scale  

NASA Astrophysics Data System (ADS)

The landslide disasters caused heavy casualties during Typhoon Morakot, 2009. This disaster is defined as largescale landslide due to the casualty numbers. This event also reflects the survey on large-scale landslide potential is so far insufficient and significant. The large-scale landslide potential analysis provides information about where should be focused on even though it is very difficult to distinguish. Accordingly, the authors intend to investigate the methods used by different countries, such as Hong Kong, Italy, Japan and Switzerland to clarify the assessment methodology. The objects include the place with susceptibility of rock slide and dip slope and the major landslide areas defined from historical records. Three different levels of scales are confirmed necessarily from country to slopeland, which are basin, catchment, and slope scales. Totally ten spots were classified with high large-scale landslide potential in the basin scale. The authors therefore focused on the catchment scale and employ risk matrix to classify the potential in this paper. The protected objects and large-scale landslide susceptibility ratio are two main indexes to classify the large-scale landslide risk. The protected objects are the constructions and transportation facilities. The large-scale landslide susceptibility ratio is based on the data of major landslide area and dip slope and rock slide areas. Totally 1,040 catchments are concerned and are classified into three levels, which are high, medium, and low levels. The proportions of high, medium, and low levels are 11%, 51%, and 38%, individually. This result represents the catchments with high proportion of protected objects or large-scale landslide susceptibility. The conclusion is made and it be the base material for the slopeland authorities when considering slopeland management and the further investigation.

Liu, Che-Hsin; Wu, Tingyeh; Chen, Lien-Kuang; Lin, Sheng-Chi

2013-04-01

187

Preliminary results of land subsidence monitoring project in Konya Closed Basin between 2006-2009 by means of GNSS observations  

NASA Astrophysics Data System (ADS)

One of the potential dangers that might arise as a result of bringing excessive amounts of groundwater to the surface of the Earth is land subsidence. Such surface deformations - these velocities may vary from a few millimetres to a few metres per year - do the greatest damage to infrastructure facilities and buildings in residential units. Agricultural lands, in which excessive irrigation is performed, and densely populated cities are more likely to suffer from land subsidence. Konya Closed Basin (KCB), where a rapid groundwater withdrawal has been observed during the last 30-40 years, is faced with such a threat. In this study, the possibility of the occurrence of land subsidence, related to groundwater withdrawal for the KCB, is assessed and the geodetic studies conducted up to now, with the intention of identifying land subsidence, are introduced. The vertical displacements of between -12 and -52 mm/year have been detected through GNSS observations collected on the 6-point test network. The land subsidence phenomenon has been developing in the areas where the groundwater is extensively used for irrigation and daily life. The results support the findings derived from the historical leveling records and point out the need of an extended study based on both GNSS and InSAR techniques for spatial and temporal mapping of land subsidence in the KCB.

Ustun, A.; Tusat, E.; Yalvac, S.

2010-06-01

188

Preliminary paleogeographic reconstruction of the Illinois basin during deposition of the Mississippian Aux Vases Formation: Implications for hydrocarbon recovery  

SciTech Connect

Extensive outcrop investigation and selective subsurface study allow definition of Illinois basin paleogeography during deposition of the Mississippian (Valmeyeran-Meramecian) Aux Vases Formation. The results incorporate an integrated approach utilizing field observations and petrographic analysis, wireline logs, subsurface maps, and cores. The Aux Vases Formation depositional system has been determined to be composed of subtidal to intertidal facies. Depositional facies in outcrop are based on rock body geometries, sedimentary structure assemblages, paleocurrent analysis, paleontology of body and trace fossils, facies relationships, and petrography. Depositional facies determined from subsurface data are based on correlation of lithologic interpretations from wireline logs, sand body geometries form isopach maps, and petrography. Specific depositional facies observed in outcrop and core and inferred from wireline logs and isopach maps are offshore bars and tidal channel complexes, extensive subtidal to lower intertidal, ripple-laminated, fine-grained quartzose sandstone. Carbonate facies occur as subtidal grainstones at or near the base of a sequence, or as high energy deposits which have been tidally reworked. This depositional system produces reservoir heterogeneities that complicate efficient hydrocarbon recovery. This diverse facies architecture is modified by tectonic and diagenetic overprinting, further segregating potential producing zones. To significantly improve recovery efficiency, predictions regarding compartmentalization can be used prior to designing a drilling program, an infill drilling program, or an application of enhanced recovery techniques.

Cole, R.D. (Illinois State Geological Survey, Champaign (United States))

1991-03-01

189

Assessing catchment hydrological functioning using discharge recession analysis based on the Kirchner's method. A case study in the Ardèche catchment (France)  

NASA Astrophysics Data System (ADS)

Catchments show a high degree of heterogeneity and variability, both in space and time. In order to deal with spatial heterogeneity and process variability in more efficient and more "natural and realistic" manner, model simplifications are needed. Governing equations such as the Darcy or Richards' equation, which are inherent in many hydrological models, are suitable for local scales. However, their application at much larger scales (e.g. catchment scale) remains problematic. The linear reservoir is a well-known and common approach in many catchment-based hydrological models. However, reality shows that those linear equations might not be representative enough for describing hydrological catchment behavior. Kirchner (2009), proposed a simple approach representing catchment behavior as a non-linear reservoir model, assuming that discharge at the outlet is only a function of catchment storage. He also proposed a method to determine non-linear reservoir parameters for this simple bucket model. The objective of this study is to investigate whether this approach is applicable to the Ardèche catchment (2355 km2), located in the southern part of France. The catchment is influenced by a Mediterranean climate with seasonal heavy rainfall events during autumn. The northern and north-western part of the catchment is characterized by steep slopes and igneous and metamorphic rock formations. A further objective is to relate the estimated parameters of the first-order dynamical system to catchment characteristics, in order to be able to develop a distributed model, adapted to the catchment response variability. The challenge for the Kirchner's method is the high geological and pedological heterogeneity of the Ardèche basin. We apply the Kirchner's method to 6 sub-catchments of the Ardèche ranging from 3.9 to 200 km2 using hourly rainfall and discharge data, in order to identify the discharge sensitivity function. We use the obtained corresponding parameters in a simple bucket model similar to the one proposed by Kirchner (2009). To have more representative potential evapotranspiration data used in the model, we introduce crop coefficient seasonality to better represent the data. Performance measurements with the Nash-Sutcliffe coefficient show performances above 80 %. These results clearly indicate that timing and magnitude of simulated discharge is correctly reproduced by the model. Additionally we assess the impact of the seasonality on the model parameterization yielding similar results in the discharge analysis. Our work shows that Kirchner's method can be applied successfully in the Ardèche catchment. Eventually, we observe that geology may be highlighted as a predictor that dominates the overall hydrological response in the basin. Kirchner, J. W. (2009), Catchments as simple dynamical systems: Catchment characterization, rainfall-runoff modeling, and doing hydrology backward, Water Resour. Res., 45, W02429, doi:10.1029/2008WR006912

Adamovic, Marko; Braud, Isabelle; Branger, Flora; Krier, Robert

2013-04-01

190

Preliminary results on the characterization of Cretaceous and lower Tertiary low-permeability (tight) gas-bearing rocks in the Wind River Basin, Wyoming.  

National Technical Information Service (NTIS)

The Wind River Basin is a structural and sedimentary basin in central Wyoming (Figure 1) that was created during the Laramide orogeny from Late Cretaceous through Eocene time. The objectives of the Wind River Basin tight gas sandstone project are to defin...

T. D. Fouch W. R. Keefer T. M. Finn

1993-01-01

191

Hydrochemical responses among nested catchments of the Sleepers River Research Watershed.  

NASA Astrophysics Data System (ADS)

We are probing chemical and isotopic tracers of dissolved organic carbon (DOC) and nitrate over both space and time to determine how stream nutrient dynamics change with increasing basin size and differ with flow conditions. At the Sleepers River Research Watershed in northeastern Vermont, USA, 20 to 30 nested sub-basins that ranged in size from 3 to 11,000 ha were sampled repeatedly under baseflow conditions. These synoptic surveys showed a pattern of heterogeneity in headwaters that converged to a consistent response at larger basin sizes and is consistent with findings of other studies. In addition to characterizing spatial patterns under baseflow, we sampled rainfall and snowmelt events over a gradient of basin sizes to investigate scaling responses under different flow conditions. During high flow events, DOC and nitrate flushing responses varied among different basins where high-frequency event samples were collected. While the DOC and nitrate concentration patterns were similar at four headwater basins, the concentration responses of larger basins were markedly different in that the concentration patterns, flushing duration, and maximum concentrations were attenuated from headwaters to the largest basin. We are using these data to explore how flow paths and solute mixing aggregate. Overall, these results highlight the complexities of understanding spatial scaling issues in catchments and underscore the need to consider event responses of hydrology and chemistry among catchments.

Sebestyen, S. D.; Boyer, E. W.; Shanley, J. B.; Kendall, C.

2005-12-01

192

Modeling ground water flow in alluvial mountainous catchments on a watershed scale.  

PubMed

In large mountainous catchments, shallow unconfined alluvial aquifers play an important role in conveying subsurface runoff to the foreland. Their relatively small extent poses a serious problem for ground water flow models on the river basin scale. River basin scale models describing the entire water cycle are necessary in integrated water resources management and to study the impact of global climate change on ground water resources. Integrated regional-scale models must use a coarse, fixed discretization to keep computational demands low and to facilitate model coupling. This can lead to discrepancies between model discretization and the geometrical properties of natural systems. Here, an approach to overcome this discrepancy is discussed using the example of the German-Austrian Upper Danube catchment, where a coarse ground water flow model was developed using MODFLOW. The method developed uses a modified concept from a hydrological catchment drainage analysis in order to adapt the aquifer geometry such that it respects the numerical requirements of the chosen discretization, that is, the width and the thickness of cells as well as gradients and connectivity of the catchment. In order to show the efficiency of the developed method, it was tested and compared to a finely discretized ground water model of the Ammer subcatchment. The results of the analysis prove the applicability of the new approach and contribute to the idea of using physically based ground water models in large catchments. PMID:18459959

Wolf, Jens; Barthel, Roland; Braun, Jürgen

2008-05-02

193

Hydrological Response of Semi-arid Degraded Catchments in Tigray, Northern Ethiopia  

NASA Astrophysics Data System (ADS)

To address water scarcity in the arid and semi-arid part of developing countries, accurate estimation of surface runoff is an essential task. In semi-arid catchments runoff data are scarce and therefore runoff estimation using hydrological models becomes an alternative. This research was initiated in order to characterize runoff response of semi-arid catchments in Tigray, North Ethiopia to evaluate SCS-CN for various catchments. Ten sub-catchments were selected in different river basins and rainfall and runoff were measured with automatic hydro-monitoring equipments for 2-3 years. The Curve Number was estimated for each Hydrological Response Unit (HRU) in the sub-catchments and runoff was modeled using the SCS-CN method at ? = 0.05 and ? = 0.20. The result showed a significant difference between the two abstraction ratios (P =0.05, df = 1, n= 132) and reasonable good result was obtained for predicted runoff at ? = 0.05 (NSE = -0.69; PBIAS = 18.1%). When using the CN values from literature runoff was overestimated compared to the measured value (e= -11.53). This research showed the importance of using measured runoff data to characterize semi-arid catchments and accurately estimate the scarce water resource. Key words: Hydrological response, rainfall-runoff, degraded environments, semi-arid, Ethiopia, Tigray

Teka, Daniel; Van Wesemael, Bas; Vanacker, Veerle; Hallet, Vincent

2013-04-01

194

Neogene tectonics in the Swiss Subalpine Molasse basin: Preliminary results from apatite (U-Th)/He ages and fault slip analyses in the Rigi area (Switzerland)  

NASA Astrophysics Data System (ADS)

Apatite fission-track (AFT) data from wells within the Swiss Subalpine Molasse basin suggest tectonic reactivation and km-scale thrusting in a triangle zone during Plio-Pleistocene times (Cederbom et al., in preparation). An offset in the AFT age/depth trend within and between wells penetrating the triangle zone suggest thrusting during or after major exhumation and basin erosion. The aims of this reconnaissance study were to test if: (1) the suggested erosion and thrusting can be verified by an independent low-temperature dating technique and if; (2) the exact location of reactivated faults can be identified. We applied apatite (U-Th)/He dating to a vertical profile of the Rigi Mountain (the hanging wall), and a horizontal transect across the Rigi thrust into the triangle zone. Additionally, detailed structural mapping was conducted in order to understand the local tectonic configuration and to document the paleo-stress. In total, 10 apatite samples from seven different locations were successfully dated with the (U-Th)/He technique. Granitic boulders were collected from the conglomeratic units in order to minimize the detrital age spread and to maximize the amount of crystal-shaped apatite grains. However, inclusions and defects were common in the apatites, so triplicates were picked and analysed for each sample. For the structural analysis, stereonets and stress inversion software were used to evaluate the collected fault slip data (mainly growth fibre and slicken-side lineations). Unfortunately, a comprehensive identification and mapping of individual faults were not possible in this densely populated and vegetated area. Single apatite (U-Th)/He ages vary between 3 and 84 Ma, probably due to unidentified inclusions or zonations. However, several sample aliquots replicate well and provide reasonable ages. In general, Pliocene ages are obtained on both sides of the Rigi thrust and the apatite ages increase with elevation along the vertical transect of the hanging wall. Moreover, two different sets of maximum horizontal stress orientations have been discerned from the fault slip analysis so far (N-S and NNW-SSE, respectively). Both represent a compression dominated stress regime for the Rigi region. The preliminary data confirm late Neogene km-scale erosion of the Subalpine Molasse (cf. Cederbom et al, 2004), but do not support more recent thrusting along the Rigi thrust. Nevertheless, thrusting further north cannot be excluded due to ambiguous results within the triangle zone. Additionally, the huge spread in single grain (U-Th)/He ages for some of the granitic boulders emphasizes the importance of analysing triplicates or more when applying the technique to crystalline apatites in this area. Cederbom, C.E. and Sinclair, H.D., Schlunegger, F., Rahn, M.K. (2004) Climate-induced rebound and exhumation of the European Alps. Geology, 32:709-712 Cederbom, C.E., Schlunegger, F., van der Beek, P., Sinclair, H., Oncken, O., Foreland basin erosion at 5-4 Ma reveals climatic, tectonic and geodynamic forcing on the European Alps (in preparation)

Lindow*, J.; Cederbom, C.; Oncken, O.; Schlunegger, F.; Gröpler, D.

2009-04-01

195

Sediment sources and its transport pathways in the Kharaa catchment, northern Mongolia  

NASA Astrophysics Data System (ADS)

Soil erosion and its subsequent transport towards and within rivers is complex, dependent on many catchment properties, hydrology and land use. However, little is known about the sources and fate of suspended sediment (SS) in the 15.000km2 Kharaa study catchment in Mongolia. This study focuses therefore on a qualitative identification of sediment sources and the quantification of the suspended sediment transport in the catchment. Geochemical sediment source fingerprinting in combination with isotope fingerprinting is used to identify and localize the most important sediment source areas in the catchment and assess their contribution to the suspended sediment load. More than 1000 grab samples from 22 river junctions of the outlet of each sub basin into the main tributary were taken in the period from 2009 to 2011. Their fine sediment fractions (<10?m) have been analysed for major elements (e.g. Si, Al, Mg) and trace elements (e.g. Ba, Pb, Sr,) using ICP-MS. The contribution of each sub basin to the SS in the main tributary has then been calculated using mixing model analysis. Additionally, isotope fingerprinting was used to assess the importance and contribution of surface, stream bank and gully erosion on total sediment load of the catchment. Biannual samples of 12 topsoil eroding surface reference sites, 4 stream banks and 4 suspended sediment samples were analysed for the atmospheric fallout radionuclides Cs-137, Pb-210 and Be-7 using gamma ray spectrometry. The sediment budget of the catchment was calculated with the help of the regional catchment scale sediment budget model (SedNet. Results suggest that only a small part of the catchment contributes considerably to the total sediment load and that gully and bank erosion might be the dominating sources in the catchment that lead to fine sediment intrusion and ecosystem degradation in the riverbed in the midstream regions. Also there seems to be a difference in erosion behaviour between spring and fall, with a higher contribution from surface erosion during summer rainfall. Future work will concentrate on scenario analysis modelling of the sediment transport in the catchment with HYPE as well as uncertainty analysis of the model.

Theuring, P.; Rode, M.

2012-04-01

196

Scenario analysis of nutrient management at the river basin scale  

Microsoft Academic Search

A new river basin model (TRANS) for studying the transport, removal and accumulation of nutrients in rivers, lakes and riparian areas has been developed and tested on data from a 115 km2 river basin in Denmark (river Gjern). The model combines catchment information on soil type and land use with a physical hydrodynamic modelling system and several semi-dynamic empirical models

B. Kronvang; L. M. Svendsen; J. P. Jensen; J. Dørge

1999-01-01

197

Runoff and Solute Mobilisation in a Semi-arid Headwater Catchment  

NASA Astrophysics Data System (ADS)

Runoff and solute transport processes contributing to stream flow were determined in a small headwater catchment in the eastern Murray-Darling Basin of Australia using hydrometric and tracer methods. Stream flow and electrical conductivity were monitored from two gauges draining a portion of upper catchment area (UCA), and a saline scalded area respectively. Results show that the bulk of catchment solute export, occurs via a small saline scald (< 2% of catchment area) where solutes are concentrated in the near surface zone (0-40 cm). Non-scalded areas of the catchment are likely to provide the bulk of catchment runoff, although the scalded area is a higher contributor on an areal basis. Runoff from the non-scalded area is about two orders of magnitude lower in electrical conductivity than the scalded area. This study shows that the scalded zone and non-scalded parts of the catchment can be managed separately since they are effectively de-coupled except over long time scales, and produce runoff of contrasting quality. Such differences are "averaged out" by investigations that operate at larger scales, illustrating that observations need to be conducted at a range of scales. EMMA modelling using six solutes shows that "event" or "new" water dominated the stream hydrograph from the scald. This information together with hydrometric data and soil physical properties indicate that saturated overland flow is the main form of runoff generation in both the scalded area and the UCA. Saturated areas make up a small proportion of the catchment, but are responsible for production of all run off in conditions experienced throughout the experimental period. The process of saturation and runoff bears some similarities to the VSA concept (Hewlett and Hibbert 1967).

Hughes, J. D.; Khan, S.; Crosbie, R.; Helliwell, S.; Michalk, D.

2006-12-01

198

Hydrological response of a Mediterranean agricultural catchment on a Vertic soil  

NASA Astrophysics Data System (ADS)

Hydrological response of vertic soils is strongly controlled by the modification of its hydraulic conditions by the shrinking and swelling cycles, which are controlled by the climatology of the year. This presents additional challenges to the already difficult task of hydrologic and erosion modelling at hillslope and catchment scale (Allen et al., 2005). However, there is limited experimental information on the hydrologic response of vertic soils at catchment scale. This communications presents a preliminary evaluation of the hydrologic impact of an small, 8 ha, catchment in Southern Spain covered by olive groves on a vertic soil. This evaluation is made on the runoff and rainfall records measured at catchment scale from September 2006 to August 2011, and at runoff plot scale from September 2000 to August 2004 and September 2009 to August 2011. These results are analyzed following the same statistical analysis described by Taguas et al. (2009) enlarging this analysis with an evaluation of the correlation between the hydrologic response of the catchment, with the evolution of the soil water content in the orchard simulated using a conceptual soil water balance model, WABOL (Abazi et al., 2012) The results of the analysis will be discussed in relation to the variability of the hydrologic response at different time and spatial scales (catchment and hillslope) and its implications for modelling and extrapolation to similar soils under different climate and crop conditions.

Gomez, J. A.; Taguas, E.; Licciardello, F.

2012-04-01

199

Rainfall/runoff processes in a small peri-urban catchment in the Andes mountains. The Rumihurcu Quebrada, Quito (Ecuador)  

NASA Astrophysics Data System (ADS)

Situated at the foot of the Pichincha volcano, the city of Quito is frequently subjected to hydroclimatic hazards. In 1995 an 11·2 km2 watershed, located in the vicinity of the city, was equipped with eight rain gauges and two flow gauges to better understand the local rainfall/runoff transformation processes. Rainfall simulation experiments were carried out on more than 40 one-square-metre plots to measure infiltration point-processes. The high density of measurement devices allowed us to identify the origin and nature of the various contributions to runoff for the different physiographic units of the watershed: urban area from an altitude of 2800 to 3200 m; farmland, pasture and forested land, and finally páramo above 3900 m. Runoff occurs mainly in the lower part of the basin and is caused by urbanization; however, the natural soils of this area can also produce Hortonian runoff, which is predominant in a few events. This contribution can be studied through rainfall simulation experiments. In the upper natural zone, the younger and more permeable soils generate less runoff on the slopes. However, almost permanently saturated contributing areas, which are located in the bottom of the quebradas, may generate flood events, the size of which depends on the extent of the area concerned. Variations in the runoff coefficients are related first to the baseflow and second to the amount of rainfall in the previous 24 h. This analysis, which underlines the complexity of a small, peri-urban, volcanic catchment, is a necessary preliminary to runoff modelling in an area where very few experiments have been carried out on small catchments.

Perrin, J. L.; Bouvier, C.; Janeau, J. L.; Ménez, G.; Cruz, F.

2001-04-01

200

Interpreting the suspended sediment dynamics in a mesoscale river basin of Central Mexico using a nested watershed approach  

NASA Astrophysics Data System (ADS)

The Cointzio river basin is located within the Mexican Transvolcanic Belt, in the Michoacán state. Land-use changes undergone over last decades lead to significant erosion processes, though affecting limited areas of the basin. Apart from generating a minor depletion of arable land by incising small headwater areas, this important sediment delivery contributed to siltation in the reservoir of Cointzio, situated right downstream of the basin. During 2009 rainy season, a detailed monitoring of water and sediment fluxes was undertaken in three headwater catchments located within the Cointzio basin (Huertitas, Potrerillos and La Cortina, respectively 2.5, 9.3 and 12.0 km2), as well as at the outlet of the main river basin (station of Santiago Undameo, 627 km2). Preliminary tests realized in 2008 underlined the necessity of carrying out a high-frequency monitoring strategy to assess the sediment dynamics in the basins of this region. In each site, water discharge time-series were obtained from continuous water-level measurements (5-min time-step), and stage-discharge rating curves. At the river basin outlet, Suspended Sediment Concentration (SSC) was estimated every 10 minutes through turbidity measurements calibrated with data from automatic sampling. In the three sub-catchments, SSC time-series were calculated using stage-triggered automatic water samplers. The three upland areas monitored in our study present distinct landforms, morphology and soil types. La Cortina is underlain by andisols, rich in organic matter and with an excellent microstructure under wet conditions. Huertitas and Potrerillos both present a severely gullied landscape, bare and highly susceptible to water erosion in degraded areas. As a result, suspended sediment yields in 2009 were expectedly much higher in these two sub-catchments (?320 t.km-2 in Huertitas and ?270 t.km-2 in Potrerillos) than in La Cortina (?40 t.km-2). The total suspended sediment export was approximately of 30 t.km-2 at the outlet, with a dominance of cohesive sediments (mainly silt and clay). Sediment delivery dynamics was found to be seasonally dependent and principally driven by the river network transport capacity. With the exception of events associated with a very high discharge peak, sub-catchments delivered very little sediment to the basin’s outlet during first events of the rainy season (corresponding to May-June period). Later on (from July until the end of the season), even low headwater sediment peaks were coupled with significant sediment fluxes at the outlet. An analysis of SSC-Q hysteresis patterns was also conducted for major flood events at each site. Anti-clockwise SSC-Q hysteresis loops were recorded most frequently at the three upland sub-catchments, while at the outlet a double-peaked SSC signal was repeatedly detected, outlining the variety in sediment contributions. The findings of this nested watershed approach suggest that during the first part of the rainy season, fine sediment loads exported from active hillslopes deposit as fluid mud layers in the lowland river channels. Once the in-channel storage capacity is loaded, the river transport potential guarantees a direct transit between headwater areas and delivery zones.

Duvert, C.; Némery, J.; Gratiot, N.; Prat, C.; Collet, L.; Esteves, M.

2009-12-01

201

Creating a catchment scale perspective for river restoration  

NASA Astrophysics Data System (ADS)

One of the major challenges in river restoration is to identify the natural fluvial landscape in catchments with a long history of river control. Intensive land use on valley floors often predates the earliest remote sensing: levees, dikes, dams, and other structures alter valley-floor morphology, river channels and flow regimes. Consequently, morphological patterns indicative of the fluvial landscape including multiple channels, extensive floodplains, wetlands, and fluvial-riparian and tributary-confluence dynamics can be obscured, and information to develop appropriate and cost effective river restoration strategies can be unavailable. This is the case in the Pas River catchment in northern Spain (650 km2), in which land use and development have obscured the natural fluvial landscape in many parts of the basin. To address this issue we used computer tools to examine the spatial patterns of fluvial landscapes that are associated with five domains of hydro-geomorphic processes and landforms. Using a 5-m digital elevation model, valley-floor surfaces were mapped according to elevation above the channel and proximity to key geomorphic processes. The predicted fluvial landscape is patchily distributed according to hillslope and valley topography, river network structure, and channel elevation profiles. The vast majority of the fluvial landscape in the main segments of the Pas River catchment is presently masked by human infrastructure, with only 15% not impacted by river control structures and development. The reconstructed fluvial landscape provides a catchment scale context to support restoration planning, in which areas of potential ecological productivity and diversity could be targeted for in-channel, floodplain and riparian restoration projects.

Benda, L.; Miller, D.; Barquín, J.

2011-09-01

202

Landscape genetic patterns of the rainbow darter Etheostoma caeruleum: a catchment analysis of mitochondrial DNA sequences and nuclear microsatellites.  

PubMed

Catchment population structure and divergence patterns of the rainbow darter Etheostoma caeruleum (Percidae: Teleostei), an eastern North American benthic fish, are tested using a landscape genetics approach. Allelic variation at eight nuclear DNA microsatellite loci and two mitochondrial DNA regions [cytochrome (cyt) b gene and control region; 2056 aligned base pairs (bp)] is analysed from 89 individuals and six sites in the Lake Erie catchment (Blanchard, Chagrin, Cuyahoga and Grand Rivers) v. the Ohio River catchment (Big Darby Creek and Little Miami River). Genetic and geographic patterning is assessed using phylogenetic trees, pair-wise F(ST) analogues, AMOVA partitioning, Mantel regression, Bayesian assignment, 3D factorial correspondence and barrier analyses. Results identify 34 cyt b haplotypes, 22 control region haplotypes and 137 microsatellite alleles whose distributions demonstrate marked genetic divergence between populations from the Lake Erie and Ohio River catchments. Etheostoma caeruleum populations in the Lake Erie and Ohio River catchments diverged c. 1.6 mya during the Pleistocene glaciations. Greater genetic separations characterize the Ohio River populations, reflecting their older habitat age and less recent connectivity. Divergence levels within the Lake Erie catchment denote more recent post-glacial origins. Notably, the western Lake Erie Blanchard River population markedly differs from the three central basin tributary samples, which are each genetically distinguishable using microsatellites. Overall relationships among the Lake Erie sites refute a genetic isolation by geographic distance hypothesis. Etheostoma caeruleum populations thus exchange few genes and have low migration among tributaries and catchments. PMID:20738685

Haponski, A E; Bollin, T L; Jedlicka, M A; Stepien, C A

2009-12-01

203

A spatially lumped model to investigate downstream sediment flux propagation within a fluvial catchment  

NASA Astrophysics Data System (ADS)

A spatially lumped process–response model, PaCMod, is presented, which calculates long time series (103–106 years) of fluvial water discharge and sediment load at the river catchment outlet, based on climatic data, drainage basin characteristics and user-defined parameters. Key aspects of the model are (i) the lumped approach, allowing for fast simulations and preserving the same resolution from palaeoclimatic conditions and geomorphological reconstructions; (ii) the parameterization of sediment routing and storage within the catchment. PaCMod was successfully tested on observed data from three present-day fluvial systems: the Meuse, the Waipaoa, and the Po Rivers. Moreover, the simulated sediment flux for the Meuse and for the Waipaoa Rivers in the late Quaternary is in agreement with published field and modelling work. PaCMod experiments show how the downstream propagation of the original climatic signal is hampered by sediment routing and storage within the catchment.

Forzoni, Andrea; de Jager, Gerben; Storms, Joep E. A.

2013-07-01

204

Determination of evaporation from a catchment water balance at a monthly time scale  

NASA Astrophysics Data System (ADS)

A method is presented to determine total evaporation from the earth's surface at a spatial scale that is adequate for linkage with climate models. The method is based on the water balance of catchments, combined with a calibrated autoregressive rainfall-runoff model. The time scale used is in the order of decades (10 days) to months. The rainfall-runoff model makes a distinction between immediate processes (interception and short term storage) and the remaining longer-term processes. Besides the calibrated rainfall-runoff model and the time series of observed rainfall and runoff, the method requires a relation between transpiration and soil moisture storage. The method is applied to data of the Bani catchment in Mali, a sub-catchment of the Niger river basin.

Savenije, H. H. G.

205

Hydrological approach using SWAT model to assess nutrient sources in a mesoscale agricultural catchment, Case study: Roxo Catchment, South Portugal.  

NASA Astrophysics Data System (ADS)

Control of diffuse pollution, caused particularly by agriculture activities, has posed effort in all EU Member Countries with most countries facing problems with the implementation of the EU Nitrate Directive (91/676/EEC). In Portugal, a considerable number of areas have been classified as "vulnerable zones" of nitrate contamination from agricultural sources. Roxo Catchment, located in Beja District, Alentejo Province, South Portugal, is inside the Alqueva area which has been classified as a vulnerable zone during 2006 by the Directive 91/767/CEE. From this agricultural catchment with 352 km2, water accumulates in a reservoir (dam) that provides water supply to Beja City, making it an important evaluation site for nutrients pollution. Therefore, this study explores the use of a spatially referenced hydrological model, Soil and Water Assessment Tool (SWAT) to evaluate stream networks of the catchment, in order to asses the effects of land use on water quality along hydrological pathways and denitrification processes, estimating the water balance and sources of nitrate and phosphate in the agricultural catchment. In this study we used data from eight years of climatic information (2001-2008), 4 different land uses and 12 soils units; final product were 12 sub-basin and 313 hydrologic response units (HRU). Comparison of the simulation results with literature data revealed that SWAT provides reasonable results, which can be used for assessing the land use impact in Roxo. The sensitivity analysis indicated low dependency of the model output to minor and moderate changes in model input. The hydrological model was calibrated using the stream flow data generated and nutrient time series from 2000-2003 and for the validation we used data from 2004 to 2008. Nutrients levels were used in order to estimate temporal variability of nutrient contributions from stream networks to the main reservoir. Scenario analysis allowed us to predict the impact of land use on the stream networks and the reservoir of the study area.

Yevenes-Burgos, M.; Mannaerts, C.

2009-04-01

206

Basin Economic Allocation Model (BEAM): An economic model of water use developed for the Aral Sea Basin  

NASA Astrophysics Data System (ADS)

The water resources of the Aral Sea basin are under increasing pressure, particularly from the conflict over whether hydropower or irrigation water use should take priority. The purpose of the BEAM model is to explore the impact of changes to water allocation and investments in water management infrastructure on the overall welfare of the Aral Sea basin. The BEAM model estimates welfare changes associated with changes to how water is allocated between the five countries in the basin (Kazakhstan, Kyrgyz Republic, Tajikistan, Turkmenistan and Uzbekistan; water use in Afghanistan is assumed to be fixed). Water is allocated according to economic optimization criteria; in other words, the BEAM model allocates water across time and space so that the economic welfare associated with water use is maximized. The model is programmed in GAMS. The model addresses the Aral Sea Basin as a whole - that is, the rivers Syr Darya, Amu Darya, Kashkadarya, and Zarafshan, as well as the Aral Sea. The model representation includes water resources, including 14 river sections, 6 terminal lakes, 28 reservoirs and 19 catchment runoff nodes, as well as land resources (i.e., irrigated croplands). The model covers 5 sectors: agriculture (crops: wheat, cotton, alfalfa, rice, fruit, vegetables and others), hydropower, nature, households and industry. The focus of the model is on welfare impacts associated with changes to water use in the agriculture and hydropower sectors. The model aims at addressing the following issues of relevance for economic management of water resources: • Physical efficiency (estimating how investments in irrigation efficiency affect economic welfare). • Economic efficiency (estimating how changes in how water is allocated affect welfare). • Equity (who will gain from changes in allocation of water from one sector to another and who will lose?). Stakeholders in the region have been involved in the development of the model, and about 10 national experts, including staff from the International Fund for Saving the Aral Sea (IFAS), have been trained in using the model. The model is publicly accessible through a web-based user interface that allows users to investigate scenarios and perform sensitivity analyses. Preliminary results suggest that: 1. At the margin, hydropower water use increases basin-wide welfare more than irrigation water use. 2. Under normal or average hydrological conditions, water scarcity is not a significant problem in the basin. 3. Under dry hydrological conditions, water scarcity is significant. Under these conditions, preliminary results suggest that cotton irrigation is less effective than other uses, particularly in Turkmenistan. 4. Investments in irrigation efficiency can have a significant impact on the effectiveness of water use for irrigation, thereby increasing the welfare of irrigation regions during dry periods.

Riegels, Niels; Kromann, Mikkel; Karup Pedersen, Jesper; Lindgaard-Jørgensen, Palle; Sokolov, Vadim; Sorokin, Anatoly

2013-04-01

207

Self Organising Maps and Canonical Correlation Analysis: application to catchment classification and PUB  

NASA Astrophysics Data System (ADS)

The scientific community indicates that the formulation of objective criteria for catchment classification is one of the main objectives for obtaining a better interpretation and representation of the spatiotemporal variability of streamflows. A promising approach to catchment classification, and in general to pattern recognition, makes use of unsupervised neural networks, and in particular Self Organising Maps (SOM), which organise input data through non-linear techniques depending on the intrinsic similarity of the data themselves (see e.g., Toth, HESS, 2009). This study considers a set of some 300 Italian catchments scattered nationwide, for which several descriptors of the streamflow regime and geomorphoclimatic characteristics are available. We qualitatively and quantitatively compared a reference classification, RC, with three alternative classifications, ACs. RC was identified by using indices of the streamflow regime as input to SOM, whereas ACs were identified on the basis of catchment descriptors available for ungauged basins. The first AC adopts the available catchment geomorphoclimatic descriptors as input to SOM. The other ACs were identified by applying SOM to sets of derived variables, which were obtained by applying Principal Component Analysis (PCA, second AC) and Canonical Correlation Analysis (CCA, third AC) to the available indices. First, the similarity between each AC and RC is assessed qualitatively, analysing how the study catchments were grouped together. Second, ACs are compared with RC in terms of accuracy of streamflow prediction. In particular, we performed an extensive cross-validation procedure to quantify nationwide the accuracy of estimates of the mean annual flow, mean annual flood and flood quantiles associated with given exceedance probabilities. Results of the study show that CCA can significantly improve the effectiveness of SOM classifications for the estimation of streamflow regime in ungauged basins.

di Prinzio, Monica; Castellarin, Attilio; Toth, Elena

2010-05-01

208

A physically-based Distributed Hydrologic Model for Tropical Catchments  

NASA Astrophysics Data System (ADS)

Hydrological models are mathematical formulations intended to represent observed hydrological processes in a watershed. Simulated watersheds in turn vary in their nature based on their geographic location, altitude, climatic variables and geology and soil formation. Due to these variations, available hydrologic models vary in process formulation, spatial and temporal resolution and data demand. Many tropical watersheds are characterized by extensive and persistent biological activity and a large amount of rain. The Agua Salud catchments located within the Panama Canal Watershed, Panama, are such catchments identified by steep rolling topography, deep soils derived from weathered bedrock, and limited exposed bedrock. Tropical soils are highly affected by soil cracks, decayed tree roots and earthworm burrows forming a network of preferential flow paths that drain to a perched water table, which forms at a depth where the vertical hydraulic conductivity is significantly reduced near the bottom of the bioturbation layer. We have developed a physics-based, spatially distributed, multi-layered hydrologic model to simulate the dominant processes in these tropical watersheds. The model incorporates the major flow processes including overland flow, channel flow, matrix and non-Richards film flow infiltration, lateral downslope saturated matrix and non-Darcian pipe flow in the bioturbation layer, and deep saturated groundwater flow. Emphasis is given to the modeling of subsurface unsaturated zone soil moisture dynamics and the saturated preferential lateral flow from the network of macrospores. Preliminary results indicate that the model has the capability to simulate the complex hydrological processes in the catchment and will be a useful tool in the ongoing comprehensive ecohydrological studies in tropical catchments, and help improve our understanding of the hydrological effects of deforestation and aforestation.

Abebe, N. A.; Ogden, F. L.

2010-12-01

209

Constraining the characteristics of sediment released from tectonically-perturbed catchments  

NASA Astrophysics Data System (ADS)

The depositional characteristics of any basin fill are the product of the coupled system of sediment release from hinterland catchments and its evolution during transport downstream. Changes to the tectonic boundary conditions governing the dynamics of erosion in upland catchments will therefore exert a significant effect on the nature and magnitude of sediment supply to channels, and subsequently neighbouring basins. While recent advances in tectonic geomorphology demonstrate the generic coupling between tectonic uplift and landscape denudation, there has been relatively little work to quantify the controls, timing, characteristics and locus of sediment release from tectonically-perturbed upland catchments, and the way in which this signal subsequently evolves downstream within the fluvial system. We address this challenge using (i) field data to evaluate the characteristics and source areas of sediment exported from modern fluvial catchments draining across active normal faults in the Italian Apennines and Greece and (ii) the CHILD landscape evolution model to investigate how the locus and volume of sediment exported from such catchments evolves through time and with the degree of tectonic perturbation. We demonstrate that rivers near the detachment limited end-member undergoing a transient response to an increase in fault uplift rate are associated with significant additional volumetric export of material derived largely from the incised zone upstream of the fault. This response produces bi-modal grain-size distributions with elevated D84 values within the transient reach for catchments eroding hard carbonate bedrock. Our data show the signal is substantially driven by landslide input from coupled hill-slopes, and we demonstrate the amplitude of the landscape response is modulated by the degree of tectonic perturbation. However, for more diffusive catchments, where weaker lithologies are eroded, the coarse fraction grain-size signal is reduced or absent despite a similar degree of tectonic perturbation. These results suggest that transient responses to tectonics control the locus, magnitude and calibre of sediment supply to basins. More widely, this work offers new insights for geomorphologists seeking to decode the interactions between hillslopes, sediment flux and channel incision in perturbed landscapes, and we provide a fresh perspective for sedimentologists trying to predict the characteristics of deposits in hangingwall basins.

Whittaker, A. C.; Attal, M.; Allen, P. A.; Cowie, P. A.

2009-12-01

210

Building SDI Bridges for Catchment Management  

Microsoft Academic Search

This research paper discusses the importance of spatial data and Spatial Data Infra- structure (SDI) for catchment management. It reviews four SDI theories including hier- archical spatial theory, diffusion theory, evolution theory and principal-agent (P-A) the- ory and discusses their characteristics and potential utilisation for catchment manage- ment. As catchment management issues are characterised by multi-level stakeholder participation in SDI

Dev Raj Paudyal; Kevin McDougall; Armando Apan

2009-01-01

211

Modelling sediment delivery ratio over the Murray Darling Basin  

Microsoft Academic Search

This paper presents a scientific and technical description of the modelling framework and the main results of modelling the long-term average sediment delivery at hillslope to medium-scale catchments over the entire Murray Darling Basin (MDB). A theoretical development that relates long-term averaged sediment delivery to the statistics of rainfall and catchment parameters will be presented. The derived flood frequency approach

Hua Lu; C. J. Moran; Ian P. Prosser

2006-01-01

212

Geochemistry of Daihai Lake sediments, Inner Mongolia, north China: Implications for provenance, sedimentary sorting, and catchment weathering  

Microsoft Academic Search

To advance the understanding of sediment distribution, catchment weathering, hydraulic sorting, and sediment provenance in a tectonically stable basin, the geochemistry of surface sediment samples from Daihai Lake in north China is presented. Mud bulk sediments were analyzed for 10 major and 30 trace elements, organic carbon, and nitrogen and for 87Sr\\/86Sr ratios in silicate fraction (acid insoluble, AI) and

Zhangdong Jin; Fuchun Li; Junji Cao; Sumin Wang; Jimin Yu

2006-01-01

213

Catchments as simple dynamical systems: Catchment characterization, rainfall-runoff modeling, and doing hydrology backward  

Microsoft Academic Search

Water fluxes in catchments are controlled by physical processes and material properties that are complex, heterogeneous, and poorly characterized by direct measurement. As a result, parsimonious theories of catchment hydrology remain elusive. Here I describe how one class of catchments (those in which discharge is determined by the volume of water in storage) can be characterized as simple first-order nonlinear

James W. Kirchner

2009-01-01

214

How tritium illuminates catchment structure  

NASA Astrophysics Data System (ADS)

Streams contain water which has taken widely-varying times to pass through catchments, and the distribution of ages is likely to change with the flow. Part of the water has 'runoff' straight to the stream with little delay, other parts are more delayed and some has taken years (in some cases decades) to traverse the deeper regolith or bedrock of the catchment. This work aims to establish the significance of the last component, which is important because it can cause catchments to have long memories of contaminant inputs (e.g. nitrate). Results of tritium studies on streams world-wide were accessed from the scientific literature. Most of the studies assumed that there were just two age-components present in the streams (i.e. young and old). The mean ages and proportions of the components were found by fitting simulations to tritium data. It was found that the old component in streams was substantial (average was 50% of the annual runoff) and had considerable age (average mean age was 10 years) (Stewart et al., 2010). Use of oxygen-18 or chloride variations to estimate streamflow mean age usually does not reveal the age or size of this old component, because these methods cannot detect water older than about four years. Consequently, the use of tritium has shown that substantial parts of streamflow in headwater catchments are older than expected, and that deep groundwater plays an active and sometimes even a dominant role in runoff generation. Difficulties with interpretation of tritium in streams in recent years due to interference from tritium due to nuclear weapons testing are becoming less serious, because very accurate tritium measurements can be made and there is now little bomb-tritium remaining in the atmosphere. Mean ages can often be estimated from single tritium measurements in the Southern Hemisphere, because there was much less bomb-tritium in the atmosphere. This may also be possible for some locations in the Northern Hemisphere. Age determination on single samples allows the variation of mean age with streamflow to be investigated, as observed in the Toenepi Catchment in New Zealand where baseflow mean ages varied from 4 to 155 years depending on flow (Morgenstern et al., 2010).

Stewart, M.; Morgenstern, U.; McDonnell, J.

2012-04-01

215

Forest management for water: a hydro-ecological modeling exercise of headwater catchments in the mixed-conifer belt of the Sierra Nevada  

NASA Astrophysics Data System (ADS)

Hydro-ecological modeling provides a cost-effective method for evaluating the effects of vegetation change on water cycling within a catchment. In mountain watersheds, change in forest vegetation not only has direct effects on transpiration rates, but also energy exchanges that influence patterns of snow ablation. In this study, treatment scenarios were implemented using the Regional Hydro-Ecological Simulation System (RHESSys) to estimate impacts on key elements of the hydrologic cycle affected by forest harvesting - snowpack accumulation, ablation, transpiration, and streamflow. Twelve headwater catchments (0.5 - 2.6 km2, 1460 - 2450m) in the mixed-conifer zone of the central Sierra Nevada, within the Sierra and Tahoe National Forests, were included for analysis. These research sites are part of the Sierra Nevada Adaptive Management Project (SNAMP), located in the headwaters of the American and Merced Rivers, and the Southern Sierra Critical Zone Observatory (CZO) in the Kings River basin. Two methods of forest harvesting were simulated in the study watersheds: 1) uniform canopy thinning, through reduction of Leaf Area Index (LAI) values and 2) strip-cut treatments, suggested as the best method for retaining snowpack. Results from this study compare the influence of vegetation on water cycle dynamics through the two harvesting treatments, initial vegetation densities, and individual catchment size. Model simulations for pre-treatment snow depth, soil moisture, and streamflow were validated with SNAMP and CZO in-situ measurements. Preliminary results show that a linear reduction of forest canopy reduces transpiration accordingly, but produces a non-linear increase in streamflow. Peak discharges also increased, occurring earlier in the spring and having more pronounced effects in the smaller catchments. Based on these results, harvesting thresholds required for obtaining increases in water yield are evaluated. Investigating the impact of forest management on these elements of the hydrologic cycle is essential in the mountain west, where ecosystem services are provided by the snowpack acting as a natural water reservoir, and streamflow which supplies a significant portion of water for hydropower, agricultural irrigation, and urban areas during the spring melt period.

Saksa, P. C.; Bales, R. C.; Ray, R. L.

2011-12-01

216

Nutrient sources in a Mediterranean catchment and their improvement for water quality management  

NASA Astrophysics Data System (ADS)

Changes in land-use or management strategies may affect water outflow, sediment and nutrients loads. Thus, there is an increasing demand for quantitative information at the catchment scale that would help decision makers or planners to take appropriate decisions. The characterisation of water status, the description of pollution sources impact, the establishment of monitoring programs and the implementation of river basin management plans require an analysis of the current basin status and estimates of the relative significance of the different sources of pollution. Particularly, in this study the Soil and Water Assessment Tool (SWAT2000) model was considered since it is an integrated hydrological model that simulates both the qualitative as well as quantitative terms of hydrological balances. It is a spatially distributed hydrological model that operates on a daily time step at catchment scale developed by the Agricultural Research Service at the U.S. Department of Agriculture. Its purpose is to simulate water sediment and chemical yields on large river basins and possible impacts of land use, climate changes and watershed management. Integrated hydrological models are, nowadays, needed to support the implementation of integrated water management plans and to comply with the current requirements of the European Water Directive. Actually, they can help in evaluating current water resources, identify pollution sources, evaluate alternative management policies. More specifically, the analysis has been applied to the Oreto catchment (77 Km2), an agricultural and urbanised catchment located in Sicily (Italy). Residential, commercial, farm and industrial settlements cover almost the entire area. The climate is Mediterranean with hot dry summer and rainy winter season. The hydrological response of this basin is dominated by long dry seasons and following wetting-up periods, during which even large inputs of rainfall may produce little or no response at the basin outlet. Regarding the inventory of point and non-point pollutants sources, the river receives a number of point source pollutants from small villages and some outskirts of Palermo, most of them untreated, and non point source pollutants from agricultural cropland and zoo-technical farms. In particular, the Oreto river receives untreated wastewater and stormwater from Altofonte (8200 inhabitants) and Pioppo (2500 inhabitants) . The model was first calibrated using meteorological, flow and water quality data collected at various stations through-out the catchment, in order to predict water and nutrient concentrations at the catchment outlet and then was used to evaluate the potential impact of various management strategies on surface water quality. The results demonstrates that point and non-point polluting sources have to be contiguously analysed because they concur to the definition of river water quality both during wet and dry periods.

Candela, Angela; Viviani, Gaspare

2010-05-01

217

K Basin Hazard Analysis  

SciTech Connect

The 105-K East (KE) and 105-K West (KW) Basins in the 100 K Area of the Hanford Site have been used for storage of irradiated N Reactor and single-pass reactor fuel. Remaining spent fuel is continuing to be stored underwater in racks and canisters in the basins while fuel retrieval activities proceed to remove the fuel from the basins. The Spent Nuclear Fuel (SNF) Project is adding equipment to the facility in preparation for removing the fuel and sludge from the basins. In preparing this hazard analysis, a variety of hazard analysis techniques were used by the K Basins hazard analysis teams, including hazard and operability studies, preliminary hazard analyses, and ''what if'' analyses. This document summarizes the hazard analyses performed as part of the safety evaluations for the various modification projects and combines them with the original hazard analyses to create a living hazard analysis document.

MCCALL, T.B.

2002-03-21

218

K Basins hazard analysis  

SciTech Connect

The 105-K East (KE) and 105-K West (KW) Basins in the 100 K Area of the Hanford Site have been used for storage of irradiated N Reactor and single-pass reactor fuel. Remaining spent fuel is continuing to be stored underwater in racks and canisters in the basins while fuel retrieval activities proceed to remove the fuel from the basins. The Spent Nuclear Fuel (SNF) Project is adding equipment to the facility in preparation for removing the fuel and sludge from the basins. In preparing this hazard analysis, a variety of hazard analysis techniques were used by the K Basins hazard analysis teams, including hazard and operability studies, preliminary hazard analyses, and ''what if'' analyses. This document summarizes the hazard analyses performed as part of the safety evaluations for the various modification projects and combines them with the original hazard analyses to create a living hazard analysis document.

MCCALL, T.B.

2002-10-09

219

An Operational Approach for Probabilistic Discharge Forecasting in Small and Medium Sized Catchments  

NASA Astrophysics Data System (ADS)

The forecast of floods related to intense rainfall events is one of the main themes of analysis in hydrometeorology and a key issue for Civil Protection systems. In this work we present a hydrometeorological probabilistic forecast system for small and medium size basins, designed for operational applications. The probabilistic approach presented here allows to face the problems related to the reduced dimension of the basins and to properly account for uncertainty sources in the prediction chain. Starting from Quantitative Precipitation Forecasts (QPF) provided by the regional center which is in charge of hydrometeorological predictions in Liguria Region, the system is able to issue probabilistic warnings both following a catchment-based criterion (single site) or following an area-based approach (multi-catchment).

Boni, G.; Ferraris, L.; Rebora, N.; Silvestro, F.

2011-12-01

220

Sediment yield estimation in mountain catchments of the Camastra reservoir, southern Italy: a comparison among different empirical methods  

NASA Astrophysics Data System (ADS)

Sedimentary budget estimation is an important topic for both scientific and social community, because it is crucial to understand both dynamics of orogenic belts and many practical problems, such as soil conservation and sediment accumulation in reservoir. Estimations of sediment yield or denudation rates in southern-central Italy are generally obtained by simple empirical relationships based on statistical regression between geomorphic parameters of the drainage network and the measured suspended sediment yield at the outlet of several drainage basins or through the use of models based on sediment delivery ratio or on soil loss equations. In this work, we perform a study of catchment dynamics and an estimation of sedimentary yield for several mountain catchments of the central-western sector of the Basilicata region, southern Italy. Sediment yield estimation has been obtained through both an indirect estimation of suspended sediment yield based on the Tu index (mean annual suspension sediment yield, Ciccacci et al., 1980) and the application of the Rusle (Renard et al., 1997) and the USPED (Mitasova et al., 1996) empirical methods. The preliminary results indicate a reliable difference between the RUSLE and USPED methods and the estimation based on the Tu index; a critical data analysis of results has been carried out considering also the present-day spatial distribution of erosion, transport and depositional processes in relation to the maps obtained from the application of those different empirical methods. The studied catchments drain an artificial reservoir (i.e. the Camastra dam), where a detailed evaluation of the amount of historical sediment storage has been collected. Sediment yield estimation obtained by means of the empirical methods have been compared and checked with historical data of sediment accumulation measured in the artificial reservoir of the Camastra dam. The validation of such estimations of sediment yield at the scale of large catchments using sediment storage in reservoirs provides a good opportunity: i) to test the reliability of the empirical methods used to estimate the sediment yield; ii) to investigate the catchment dynamics and its spatial and temporal evolution in terms of erosion, transport and deposition. References Ciccacci S., Fredi F., Lupia Palmieri E., Pugliese F., 1980. Contributo dell'analisi geomorfica quantitativa alla valutazione dell'entita dell'erosione nei bacini fluviali. Bollettino della Società Geologica Italiana 99: 455-516. Mitasova H, Hofierka J, Zlocha M, Iverson LR. 1996. Modeling topographic potential for erosion and deposition using GIS. International Journal of Geographical Information Systems 10: 629-641. Renard K.G., Foster G.R., Weesies G.A., McCool D.K., Yoder D.C., 1997. Predicting soil erosion by water: a guide to conservation planning with the Revised Universal Soil Loss Equation (RUSLE), USDA-ARS, Agricultural Handbook No. 703.

Lazzari, Maurizio; Danese, Maria; Gioia, Dario; Piccarreta, Marco

2013-04-01

221

Preliminary Assessment of Infiltration Rates and Effects on Water Quality of Selected Infiltration Media for Use in Highway Runoff Retention Basins in Washington State.  

National Technical Information Service (NTIS)

Infiltration experiments were undertaken to investigate an infiltration medium that could be used in retention basins to decrease the infiltration rate to between 5 and 10 inches per hour and to also decrease the concentrations of some pollutants in highw...

K. C. Ames E. L. Inkpen L. M. Frans W. R. Bidlake

2001-01-01

222

Preliminary Basin Analysis of Latest Miocene Conglomerate Near Bahía Kino, Coastal Sonora: A New Record of Crustal Deformation During Initial Opening of the Northern Gulf of California  

Microsoft Academic Search

In coastal Sonora northwest of Bahía Kino, we have initiated a basin-analysis study of nonmarine conglomerate (Tcg) that overlies and is locally interbedded with the 6.4-Ma Tuff of Mesa Cuadrada (Tmc). Tcg conglomerate is deeply eroded and cut by a complex set of syn- to post-basinal, N- to NNE-striking normal faults and NW-striking dextral strike-slip faults. We carried out detailed

R. J. Dorsey; T. C. Peryam; S. Bennett; M. E. Oskin; A. Iriondo

2008-01-01

223

Epiphytic diatoms associated with a submerged macrophyte, Vallisneria aethiopica , in the shallow marginal areas of Sanyati Basin (Lake Kariba): a preliminary assessment of their use as biomonitoring tools  

Microsoft Academic Search

Diatom assemblages attached to the leaves of the submerged macrophyte Vallisneria aethiopica in the shallow waters of the Sanyati Basin in Lake Kariba were analysed to assess their response to human impact. Human activities\\u000a occurring within approximately 500 m of the shoreline were assessed at ten sampling sites along the shores of the basin. Eleven\\u000a human activity factors were assessed and

C. Phiri; J. Day; M. Chimbari; E. Dhlomo

2007-01-01

224

Evaluation of erosion in equipped basins: preliminary results of a comparison between the Gavrilovic model and direct measurements of sediment transport  

Microsoft Academic Search

The study of the hydrologic characters of a water course permits the correct management of the corresponding basin and a greater\\u000a control over the water resources of the whole basin; therefore, a suitable planning and maintenance of the necessary interventions\\u000a along the water course, especially in proximity of the outlet to sea, becomes necessary. An evaluation of the solid transport

A. Tazioli

2009-01-01

225

Surface runoff in a torrent catchment area in Middle Europe and its prevention  

Microsoft Academic Search

The Schesa, a sinister contributory torrent to the Ill river near Bludenz (federal province of Vorarlberg) is the largest\\u000a basin-shaped gully of Middle Europe and endangers the underlying villages by torrential debris flow and gigantic mass movements.\\u000a The catchment is characterized by a complex geological situation, high annual precipitation and torrential rains from spring\\u000a to early autumn, which cause enormous

G. Markart; B. Kohl; R. Kirnbauer; H. Pirkl; H. Bertle; R. Stern; A. Reiterer; P. Zanetti

2006-01-01

226

Sources and yields of dissolved carbon in northern Wisconsin stream catchments with differing amounts of peatland  

Microsoft Academic Search

In five tributary streams (four inflowing and one outflowing) of 1600-ha Trout Lake in northern Wisconsin, USA, we examined\\u000a factors that can affect the magnitude of stream flow and transport of dissolved organic and inorganic carbon (DOC and DIC)\\u000a through the streams to the lake. One catchment, the Allequash Creek basin, was investigated in more detail to describe the\\u000a dynamics

John F. Elder; Nancy B. Rybicki; Virginia Carter; Victoria Weintraub

2000-01-01

227

A physically based distributed subsurface-surface flow dynamics model for forested mountainous catchments  

NASA Astrophysics Data System (ADS)

This study was designed to develop a physically based hydrological model to describe the hydrological processes within forested mountainous river basins. The model describes the relationships between hydrological fluxes and catchment characteristics that are influenced by topography and land cover. Hydrological processes representative of temperate basins in steep terrain that are incorporated in the model include intercepted rainfall, evaporation, transpiration, infiltration into macropores, partitioning between preferential flow and soil matrix flow, percolation, capillary rise, surface flow (saturation-excess and return flow), subsurface flow (preferential subsurface flow and baseflow) and spatial water-table dynamics. The soil-vegetation-atmosphere transfer scheme used was the single-layer Penman-Monteith model, although a two-layer model was also provided. The catchment characteristics include topography (elevation, topographic indices), slope and contributing area, where a digital elevation model provided flow direction on the steepest gradient flow path. The hydrological fluxes and catchment characteristics are modelled based on the variable source-area concept, which defines the dynamics of the watershed response. Flow generated on land for each sub-basin is routed to the river channel by a kinematic wave model. In the river channel, the combined flows from sub-basins are routed by the Muskingum-Cunge model to the river outlet; these comprise inputs to the river downstream. The model was applied to the Hikimi river basin in Japan. Spatial decadal values of the normalized difference vegetation index and leaf area index were used for the yearly simulations. Results were satisfactory, as indicated by model efficiency criteria, and analysis showed that the rainfall input is not representative of the orographic lifting induced rainfall in the mountainous Hikimi river basin. Also, a simple representation of the effects of preferential flow within the soil matrix flow has a slight significance for soil moisture status, but is insignificant for river flow estimations. Copyright

Mulungu, Deogratias M. M.; Ichikawa, Yutaka; Shiiba, Michiharu

2005-12-01

228

Hydrograph prediction in ungauged basins - a comparative assessment of studies  

NASA Astrophysics Data System (ADS)

The objective of this assessment is to compare studies predicting runoff hydrographs in ungauged catchments. The aim is to learn from the similarities and differences between catchments in different places, and to interpret the differences in performance in terms of the underlying climate-landscape controls. The assessment is performed at two levels. The Level 1 assessment is a meta-analysis of 33 studies reported in the literature involving 3874 catchments. The Level 2 assessment consists of a more focused and detailed analysis of individual basins from selected studies from Level 1 in terms of how the leave-one-out cross-validation performance depends on climate and catchment characteristics as well as on the chosen regionalisation method. The results indicate that runoff hydrograph predictions in ungauged catchments tend to be more accurate in humid than in arid catchments and more accurate in large than in small catchments. The dependence of performance on elevation differs by regions and depends on how aridity varies with elevation and air temperature. The effect of parameter regionalisation method on model performance differs between studies. However, there is a tendency towards a somewhat lower performance of regressions than other methods in those studies that apply different methods in the same region. In humid catchments spatial proximity and similarity methods perform best while in arid catchments similarity and parameter regression methods perform slightly better. For studies with a large number of catchments (dense stream gauge network) there is a tendency for spatial proximity and geostatistics to perform better than regression or regionalisation based on simple averaging of model parameters from gauged catchments. There was no clear relationship between predictive performance and the number of regionalised model parameters. The implications of the findings are discussed in the context of model building.

Parajka, Juraj; Viglione, Alberto; Rogger, Magdalena; Salinas, Jose Luis; Sivapalan, Murugesu; Bloeschl, Guenter

2013-04-01

229

Catchment management and the Great Barrier Reef  

Microsoft Academic Search

Pollution of coastal regions of the Great Barrier Reef is dominated by runoff from the adjacent catchment. Catchment land-use is dominated by beef grazing and cropping, largely sugarcane cultivation, with relatively minor urban development. Runoff of sediment, nutrients and pesticides is increasing and for nitrogen is now four times the natural amount discharged 150 years ago. Significant effects and potential

J. Brodie; C. Christie; M. Devlin; D. Haynes; S. Morris; M. Ramsay; J. Waterhouse; H. Yorkston

230

Constraining sediment fluxes and grain-size characteristics in tectonically-perturbed catchments.  

NASA Astrophysics Data System (ADS)

The depositional characteristics of any basin fill (the sink) are fundamentally a product of the coupled system of sediment release from hinterland catchments (the source) and its evolution during transport downstream. Changes to the tectonic boundary conditions governing the dynamics of erosion in upland catchments will therefore exert a significant effect on the nature and magnitude of sediment supply to neighbouring basins. While recent advances in tectonic geomorphology demonstrate the generic coupling between tectonic uplift and landscape denudation, there has been relatively little work to quantify the timing, characteristics and locus of sediment release from tectonically-perturbed upland catchments, and the way in which this signal subsequently evolves downstream within the fluvial system. We address this challenge using (i) field data to evaluate the characteristics and source areas of sediment exported from modern fluvial catchments draining across active normal faults in the Central Apennines in Italy and (ii) the CHILD landscape evolution model to investigate how the locus and volume of sediment exported from such catchments evolves through time and with the degree of tectonic perturbation. We demonstrate that catchments undergoing a transient response to an increase in fault uplift rate at 0.8 Ma are associated with significant volumetric export of material derived largely from an incised zone upstream of the fault, producing bi-modal grain-size distributions with elevated D84values within the transient reach. This response is substantially driven by input from coupled hill-slopes, and we show the amplitude and timescale of the landscape response is modulated by the degree of tectonic perturbation. Our results challenge the view the sediment is sourced uniformly from tectonically active catchments, and demonstrate that transient responses to tectonics control the locus, magnitude and calibre of sediment supply to basins. More widely, this work offers new insights for geomorphologists seeking to decode the interactions between hill-slopes, sediment flux and channel incision in transient landscapes, and we provide a fresh perspective for sedimentologists trying to predict proximal hanging-wall stratigraphy in normal fault bounded terrains.

Whittaker, A. C.; Attal, M.; Allen, P. A.

2009-04-01

231

Preliminary results on the characterization of Cretaceous and lower Tertiary low-permeability (tight) gas-bearing rocks in the Wind River Basin, Wyoming  

SciTech Connect

The Wind River Basin is a structural and sedimentary basin in central Wyoming (Figure 1) that was created during the Laramide orogeny from Late Cretaceous through Eocene time. The objectives of the Wind River Basin tight gas sandstone project are to define the limits of the tight gas accumulation in the basin and to estimate in-place and recoverable gas resources. The approximate limits of the tight gas accumulation are defined from available drillhole information. Geologic parameters, which controlled the development of the accumulation, are studied in order to better understand the origins of tight gas accumulations, and to predict the limits of the accumulation in areas where little drillhole information is available. The architecture of sandstone reservoirs are studied in outcrop to predict production characteristics of similar reservoirs within the tight gas accumulation. Core and cuttings are used to determine thermal maturities, quality of source rocks, and diagenetic histories. Our work thus far has concentrated in the Wind River Indian Reservation in the western part of the basin.

Fouch, T.D.; Keefer, W.R.; Finn, T.M. [and others

1993-12-31

232

Hydrogeochemical responses of forested catchments  

NASA Astrophysics Data System (ADS)

The AGU Chapman Conference on Hydrogeochemical Responses of Forested Catchments was held September 18-21, 1989, in Bar Harbor, Maine, and brought together geochemists with interests in determining the effects of different geochemical processes on resulting surface water chemistry and hydrologists with interests in explaining flow generation in catchments with the aim of fostering better communication between the two groups on the topic of geochemical and hydrological interactions in intermediate-size watersheds. An important point of consideration was the emphasis on intermediate-size watersheds, which we defined operationally as watersheds of sufficient size to yield flow and habitat suitable for supporting at least a marginal recreational fishery, for example, on the order of at least a few square kilometers in the northeast United States. This emphasis is important because it is the potential effects of pollutants, as modified by watershed geochemical and hydrological processes, in watersheds of this scale that drive much of the concern of the nation's regulatory agencies with regard to adverse environmental effects and required water quality legislation. A good example of this is the current concern over potential adverse effects of acidic deposition on surface water quality, especially in streams that support upland sport fisheries.

Robbins Church, M.; Hornberger, George; Driscoll, Charles; Sklash, Michael; Hemond, Harold

233

Undiscovered Petroleum of the Brazilian Interior Sag Basins  

Microsoft Academic Search

This paper, the second in a series dealing with undiscovered petroleum in South American basins (exclusive of Venezuela and Colombia), focuses on the four large intracratonic (or interior) sag basins of Brazil: the Solimoes, Amazonas, Parnaiba, and Parana. The smaller Chaco basin also is discussed, although in less detail. Preliminary estimates of undiscovered hydrocarbons in the five basins are 0.228

John Kingston; John R. Matzko

1995-01-01

234

Runoff and solute mobilization processes in a semiarid headwater catchment  

NASA Astrophysics Data System (ADS)

Runoff and solute transport processes contributing to streamflow were determined in a small headwater catchment in the eastern Murray-Darling Basin of Australia using hydrometric and tracer methods. Streamflow and electrical conductivity were monitored from two gauges draining a portion of the upper catchment area (UCA) and a saline scalded area, respectively. Runoff in the UCA was related to the formation of a seasonally perched aquifer in the near-surface zone (0-0.4 m). A similar process was responsible for runoff generation in the saline scalded area. However, saturation in the scald area was related to the proximity of groundwater rather than low subsurface hydraulic conductivity. Because of higher antecedent water content, runoff commenced earlier in winter from the scald than did the UCA. Additionally, areal runoff from the scald was far greater than from the UCA. Total runoff from the UCA was higher than the scald (15.7 versus 3.5 mL), but salt export was far lower (0.6 and 5.4 t for the UCA and scald area, respectively) since salinity of the scald runoff was far higher than that from the UCA, indicating the potential impact of saline scalded areas at the catchment scale. End-member mixing analysis modeling using six solutes indicated that most runoff produced from the scald was "new" (40-71%) despite the proximity of the groundwater surface and the high antecedent moisture levels. This is a reflection of the very low hydraulic conductivity of soils in the study area. Nearly all chloride exported to the stream from the scald emanated from the near-surface zone (77-87%). Runoff and solute mobilization processes depend upon seasonal saturation occurring in the near-surface zone during periods of low evaporative demand and generation of saturated overland flow.

Hughes, Justin D.; Khan, Shahbaz; Crosbie, Russell S.; Helliwell, Stuart; Michalk, David L.

2007-09-01

235

The hydrological effects of fire in South African mountain catchments  

Microsoft Academic Search

Streamflow and its storm-flow elements in four catchments were analyzed by the paired catchment method for a response to fire. Prior to burning two of the catchments were vegetated with over-mature fynbos (the indigenous scrub vegetation of the southwestern Cape, South Africa), one was afforested with Pinus radiata and the fourth with Eucalyptus fastigata. One of the fynbos catchments was

D. F. Scott

1993-01-01

236

Temporal inequality in catchment discharge and solute export  

NASA Astrophysics Data System (ADS)

A framework is developed for characterizing the temporal inequality of stream discharge and solute loads to receiving waters using Lorenz diagrams and the associated Gini coefficient, G. These descriptors are used to illustrate a broad range of observed flow variability with a synthesis of multidecadal flow data from 22 rivers in Florida. Multidecadal phosphorus load data from four of the primary tributaries to Lake Okeechobee, Florida, and sodium and nitrate load data from nine of the Hubbard Brook, New Hampshire, long-term study site catchments are used to examine the relation between the inequality of flow and load. The intra-annual loads to Lake Okeechobee are shown to be highly unequal, such that 90% of the annual load is delivered in as little as 15% of the time. Analytic expressions are developed for measures of inequality in terms of parameters of the lognormal distribution under general conditions that include periods of zero flow. In cases where variability of concentrations is low compared to that of flows (chemostatic conditions), such as for phosphorus in the Lake Okeechobee basin and sodium in Hubbard Brook, the temporal inequality of flow is a strong surrogate for load inequality. However, in cases where variability of concentrations is high compared to that of flows (chemodynamic conditions), such as for nitrate in the Hubbard Brook catchments, load inequality is greater than flow inequality. The measured degree of correspondence between flow and load inequality for these data sets is shown to be well described using the general inequality framework introduced here.

Jawitz, James W.; Mitchell, Jennifer

2011-10-01

237

Catchment similarity and classification in areas of high hydrologic gradients: the case of Chilean Patagonia  

NASA Astrophysics Data System (ADS)

The Baker River Basin is located in Patagonia, Southern South America, with a total drainage area of 26,726 km2 (second-largest river basin in Chile). The Baker River has the highest mean annual discharge rate of all Chilean rivers (1,133 m3/s), and flows out of Bertrand Lake, which in turn receives the draining waters from the General Carrera Lake (surface area of about 1800 km2, Latin America's second largest). Geology and climate gradients are even more extreme than in the rest of the country, from mountain to sea, and sometimes having mean annual rainfalls change from 8000 mm to 400 mm in less than 60 km. Bigger basins, like the Baker, have Eastern sub-basins with even a semi-arid character, whereas Western sub-catchments drain from ice fields. Thus, flow regimes may have very diverse characters in combination. And regarding sediment, although many rivers are born in lakes (many bi-national), they have important profile slopes and plenty of sediment available (partly due to glacial deposits). In spite of this huge natural variability, there is scant data due to low resources and remoteness: few meteorological and flow stations (having few decades or much shorter data series), and lack of stations in Western areas, linked to mountainous terrain, glaciers, and the ice fields. Nevertheless, decisions are being made with what seems extremely limited hydro-meteorological, streamflow, and in general, river data. In fact, Chile is currently in a crossroad due to mega projects being planned in Aysén, Chilean Patagonia (at least 5 hydropower dams producing more than 2000 MW). We characterize streamflows for ungauged basins, such as floods, mean annual flows, and flow duration curves, which can then be used related to a more sustainable design and operation of dams for hydropower. Relations extracted from gauged catchments to their geomorphologic characteristics and indices will be used to transfer those relations to ungauged catchments.

Dussaillant, A.; Buytaert, W.; Maturana, O.; Arias, M.

2009-04-01

238

Going With the Flow: Participatory Action Research and River Catchment Management  

NASA Astrophysics Data System (ADS)

Public participation, now mainstreamed as a desirable goal in research and policy has a wide variety of different models, classifications, approaches, tools, mechanisms and processes that are utilized across science and social science utilise. Demands for public participation in environmental issues have found particular resonance within recent European water legislation, specifically the Water Framework Directive (2000/60/EC). In the UK River Basin Plans are under the jurisdiction of the Environment Agency (EA) and the practice of their management is currently being trialed through the EA's management of 10 trial catchments. In these trials, the Environment Agency has outlined its wish to explore improved ways of engaging with people so as to develop shared understandings of problems within catchments. In this work, we report on project outcomes funded under the Rural Economy and Land Use Program (Relu) in which we worked with the Lune Rivers Trust. The project was the first in the UK to use a Participatory Action Research (PAR) approach to understanding and creating tools to address problems in river catchments. PAR is a distinct approach to participation because it is driven by participants (people who have a stake in the issue being researched) rather than an outside sponsor, funder or academic (although they may be invited to help); it offers a democratic model of who can produce, own and use knowledge; it is collaborative at every stage, involving discussion, pooling skills and working together; and it is intended to result in some action, change or improvement on the issue being researched, towards more socially and environmentally just outcomes. Both the project and the tools we coproduced resonate very strongly with current policy objects for river catchments as outlined above. We argue that PAR has particular resonance with the above focus of catchment management particularly in light of future uncertainties with climate change. As such, it offers a critical reflection on approaches to catchment management that characterize themselves as 'participatory'.

Whitman, G.; Pain, R.

2012-04-01

239

Adaptations of a physical-based hydrological model for alpine catchments. Application to the upper Durance catchment.  

NASA Astrophysics Data System (ADS)

The impact of global change on water resources is expected to be especially pronounced in mountainous areas. Future hydrological scenarios required for impact studies are classically simulated with hydrological models from future meteorological scenarios based on GCMs outputs. Future hydrological regimes of French rivers were estimated following this methodology by Boé et al. (2009) with the physical-based hydrological model SAFRAN-ISBA-MODCOU (SIM), developed by Météo-France. Scenarios obtained for the Alps seem however not very reliable due to the poor performance achieved by the model for the present climate over this region. This work presents possible improvements of SIM for a more relevant simulation of alpine catchments hydrological behavior. Results obtained for the upper Durance catchment (3580 km2) are given for illustration. This catchment is located in Southern French Alps. Its outlet is the Serre-Ponçon lake, a large dam operated for hydropower production, with a key role for water supply in southeastern France. With altitudes ranging from 700 to 4100 meters, the catchment presents highly seasonal flows: minimum and maximum discharges are observed in winter and spring respectively due to snow accumulation and melt, low flows are sustained by glacier melt in late summer (39 km2 are covered by glaciers), major floods can be observed in fall due to large liquid precipitation amounts. Two main limitations of SIM were identified for this catchment. First the 8km-side grid discretization gives a bad representation of the spatial variability of hydrological processes induced by elevation and orientation. Then, low flows are not well represented because the model doesn't include deep storage in aquifers nor ice melt from glaciers. We modified SIM accordingly. For the first point, we applied a discretization based on topography : we divided the catchment in 9 sub-catchments and further 300 meters elevation bands. The vertical variability of meteorological inputs and vegetation cover could be thus better accounted for. Then, each elevation band is divided in 7 exposure classes, in order to represent the influence on snow cover of the solar radiation spatial variability . This discretisation results in 539 Hydrological Units where hydrological processes are assumed to be homogeneous. For the second point, we first included the possibility for glacier melt in previous discretization. We next added a conceptual non-linear underground reservoir in order to simulate water retention by aquifers. These adaptations lead to a clear improvement of simulations for all the hydrometric stations. Daily simulated discharges fit well with measurements (Nash score = 0.8). The model has a good ability to simulate interannual variability and it is robust under a long simulation period (1959-2006). This encourages us to use it in a modified climate context. We studied the effect of each model improvement with a set of sensitivity tests. Accounting for elevation bands allows simulating more persistent snow cover at high altitudes, contributing later to river flows. Adding underground storage leads to delay the snowmelt runoff transfer in river. The exposure influence is not so sensitive for discharges simulation, but it gives a more accurate description of the spatial variability of snow cover. Although glaciered areas are very small compared to total basin area, a better simulation of summer low flows is obtained including a glacier melt module. Despite previous improvements, winter low flows are still slightly underestimated. As suggested by a simple sensitivity analysis, this could be partly due to the fact that the model doesn't correctly simulate basal snowmelt by ground heat flow.

Lafaysse, Matthieu; Hingray, Benoit

2010-05-01

240

Water quantity and quality optimization modeling of dams operation based on SWAT in Wenyu River Catchment, China.  

PubMed

Water quantity and quality joint operation is a new mode in the present dams' operation research. It has become a hot topic in governmental efforts toward integrated basin improvement. This paper coupled a water quantity and quality joint operation model (QCmode) and genetic algorithm with Soil and Water Assessment Tool (SWAT). Together, these tools were used to explore a reasonable operation of dams and floodgates at the basin scale. Wenyu River Catchment, a key area in Beijing, was selected as the case study. Results showed that the coupled water quantity and quality model of Wenyu River Catchment more realistically simulates the process of water quantity and quality control by dams and floodgates. This integrated model provides the foundation for research of water quantity and quality optimization on dam operation in Wenyu River Catchment. The results of this modeling also suggest that current water quality of Wenyu River will improve following the implementation of the optimized operation of the main dams and floodgates. By pollution control and water quantity and quality joint operation of dams and floodgates, water quality of Wenyu river will change significantly, and the available water resources will increase by 134%, 32%, 17%, and 82% at the downstream sites of Sha River Reservoir, Lutong Floodgate, Xinpu Floodgate, and Weigou Floodgate, respectively. The water quantity and quality joint operation of dams will play an active role in improving water quality and water use efficiency in Wenyu River Basin. The research will provide the technical support for water pollution control and ecological restoration in Wenyu River Catchment and could be applied to other basins with large number of dams. Its application to the Wenyu River Catchment has a great significance for the sustainable economic development of Beijing City. PMID:20237841

Zhang, Yongyong; Xia, Jun; Chen, Junfeng; Zhang, Minghua

2010-03-17

241

The relationship between soil heterotrophic activity, soil dissolved organic carbon (DOC) leachate, and catchment-scale DOC export in headwater catchments  

NASA Astrophysics Data System (ADS)

Dissolved organic carbon (DOC) from terrestrial sources forms the major component of the annual carbon budget in many headwater streams. In high-elevation catchments in the Rocky Mountains, DOC originates in the upper soil horizons and is flushed to the stream primarily during spring snowmelt. To identify controls on the size of the mobile soil DOC pool available to be transported during the annual melt event, we measured soil DOC production across a range of vegetation communities and soil types together with catchment DOC export in paired watersheds in Summit County, Colorado. Both surface water DOC concentrations and watershed DOC export were lower in areas where pyrite weathering resulted in lower soil pH. Similarly, the amount of DOC leached from organic soils was significantly smaller (p < 0.01) at sites having low soil pH. Scaling point source measurements of DOC production and leaching to the two basins and assuming only vegetated areas contribute to DOC production, we calculated that the amount of mobile DOC available to be leached to surface water during melt was 20.3 g C m-2 in the circumneutral basin and 17.8 g C m-2 in the catchment characterized by pyrite weathering. The significant (r2=0.91 and p < 0.05), linear relationship between over-winter CO2 flux and the amount of DOC leached from upper soil horizons during snowmelt suggests that the mechanism for the difference in production of mobile DOC was heterotrophic processing of soil carbon in snow-covered soil. Furthermore, this strong relationship between over-winter heterotrophic activity and the size of the mobile DOC pool present in a range of soil and vegetation types provides a likely mechanism for explaining the interannual variability of DOC export observed in high-elevation catchments.

Brooks, P. D.; McKnight, D. M.; Bencala, K. E.

1999-06-01

242

Prediction in Ungauged Basin Based on Hydrological Similarity Analysis  

NASA Astrophysics Data System (ADS)

Extrapolation of response information from gauged to ungauged basins is a appropriate and widely used method for Prediction in Ungauged Basin (PUB). Hydrological similarity between gauged and ungauged basins, derived from their similarity in how they respond to precipitation input, is the basis for classification, for transferability and regionalization. Usual measure of similarity is the correlation coefficient calculated pair wise from discharge time series. Unfortunately this measure mixes meteorological and hydrological effects. If the same catchment would have a different weather then the correlation becomes low and the catchments are considered as dissimilar. Two catchments are similar if in the common domain of meteorological forcing the resulting discharge is similar. Similarity can be defined as apparent similarity as well as behavioral similarity. Apparent similarity is defined on the basis of observable catchment properties, while behavioral similarity can be judged through the utilization of hydrological models. The fact that the hydrological similarity requires some kind of a model is not necessarily a good thing; this is why hydrological models usually agree with each other concerning the similarity of catchments. Under changing hydrological regimes, many standard procedures in hydrology are no longer valid and new analytical procedures need to be developed (or existing ones modified). This study is concentrating on developing new way for prediction in ungauged basins by analyzing the hydrological similarity between catchments. Empirical Copula density based dissimilarity measure is one of the approaches to predict ungauged basins in my research. Improve process understanding through research, as it is about prediction, where the increased focus on process is seen as the pathway to better model estimates for the future.

Huang, Y.; Bárdossy, A.; Wagener, T.

2011-12-01

243

Geomorphological characterization of endorheic basins in northern Chile  

NASA Astrophysics Data System (ADS)

Quantitative geomorphology regroups a large number of interesting tools to characterize natural basins across scales. The application of these tools to several river basins allows the description and comparison of geomorphological properties at different spatial scales as oppose to more traditional descriptors that are typically applied at a single scale, meaning the catchment scale. Most of the recent research using these quantitative geomorphological tools has focused on open catchments and no specific attention has been given to endorheic basins, and the possibility of having particular features that distinguish them from exorheic catchments. The main objective of our study is to characterize endorheic basins and investigate whether these special geomorphological features can be identified. Because scaling invariance is a widely observed and relatively well quantified property of open basins, it provides a suitable tool to characterize differences between the geomorphology of closed and open basins. Our investigation focuses on three closed basins located in northern Chile which describe well the diversity in the geomorphology and geology of this arid region. Results show that endhoreic basins exhibit different slope-area and flow paths sinuosity regimes compared to those observed in open basins. These differences are in agreement with the particular self-similar behavior across spatial scales of the Euclidean length of subcatchments, as well as the Hack's law and Horton's ratios. These regimes imply different physical processes inside the channel network regardless of the basin area, and they seem to be related to the endorheic character of these basins. The analysis of the probability density functions of contributing areas and lengths to the lower region shows that the hypothesis of self-similarity can also be applied to closed basins. Theoretical expressions for these distributions were derived and validated by the data. Future research will focus on (1) applying similar analyses in other locations and comparing the results, and (2) understanding and modeling the effects of groundwater in forming the landscape of these arid regions.

Dorsaz, J.; Gironas, J. A.; Escauriaza, C. R.; Rinaldo, A.

2011-12-01

244

Water Catchment and Storage Monitoring  

NASA Astrophysics Data System (ADS)

Sensors and Sensor Networks technologies provide the means for comprehensive understanding of natural processes in the environment by radically increasing the availability of empirical data about the natural world. This step change is achieved through a dramatic reduction in the cost of data acquisition and many orders of magnitude increase in the spatial and temporal granularity of measurements. Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) is undertaking a strategic research program developing wireless sensor network technology for environmental monitoring. As part of this research initiative, we are engaging with government agencies to densely monitor water catchments and storages, thereby enhancing understanding of the environmental processes that affect water quality. In the Gold Coast hinterland in Queensland, Australia, we are building sensor networks to monitor restoration of rainforest within the catchment, and to monitor methane flux release and water quality in the water storages. This poster will present our ongoing work in this region of eastern Australia. The Springbrook plateau in the Gold Coast hinterland lies within a World Heritage listed area, has uniquely high rainfall, hosts a wide range of environmental gradients, and forms part of the catchment for Gold Coast's water storages. Parts of the plateau are being restored from agricultural grassland to native rainforest vegetation. Since April 2008, we have had a 10-node, multi-hop sensor network deployed there to monitor microclimate variables. This network will be expanded to 50-nodes in February 2010, and to around 200-nodes and 1000 sensors by mid-2011, spread over an area of approximately 0.8 square kilometers. The extremely dense microclimate sensing will enhance knowledge of the environmental factors that enhance or inhibit the regeneration of native rainforest. The final network will also include nodes with acoustic and image sensing capability for monitoring higher level parameters such as fauna diversity. The regenerating rainforest environment presents a number of interesting challenges for wireless sensor networks related to energy harvesting and to reliable low-power wireless communications through dense and wet vegetation. Located downstream from the Springbrook plateau, the Little Nerang and Hinze dams are the two major water supply storages for the Gold Coast region. In September 2009 we fitted methane, light, wind, and sonar sensors to our autonomous electric boat platform and successfully demonstrated autonomous collection of methane flux release data on Little Nerang Dam. Sensor and boat status data were relayed back to a human operator on the shore of the dam via a small network of our Fleck™ nodes. The network also included 4 floating nodes each fitted with a string of 6 temperature sensors for profiling temperature at different water depths. We plan to expand the network further during 2010 to incorporate floating methane nodes, additional temperature sensing nodes, as well as land-based microclimate nodes. The overall monitoring system will provide significant data to understand the connected catchment-to-storage system and will provide continuous data to monitor and understand change trends within this world heritage area.

Bruenig, Michael; Dunbabin, Matt; Moore, Darren

2010-05-01

245

Monitoring the runoff response of an ephemeral rocky basin: a case study in the Dolomites (North-Eastern Italy)  

NASA Astrophysics Data System (ADS)

In high elevation alpine catchments, first-order streams are often constituted by steep and narrow channels bound by cliffs. These channels frequently have a structural control imposed by fractures and faults in bedrock and typically constitute temporary streams where snowmelt processes strongly influence runoff. Rocky headwater basins show a different hydrological response with respect to soil-mantled basins and their hydrology is poorly known due to the lack of widespread monitoring sites. Herein we present the preliminary results achieved through an experimental hydro-meteorological monitoring network setup in a 0.1 km2 rocky headwater basin located on the southern flank of the Sella Group in the Dolomites (North-Eastern Italy). Elevation ranges between 2700 m, at the outlet, and 3174 m, with an average value of 2950 m. Geology is constituted mainly by the Norian "Dolomia Principale" (Dolomite) featuring a complex structural setting. The monitoring network, active since 2009, is designed with three rain gauges with a time rate of 5 minutes. Two are located at 2609 and 2597 m (close to the outlet), and the third is located on the divide in the central part of the basin (2911 m). Runoff at the outlet is monitored by a pressure transducer. The time interval was set at 5 minutes in the summer months in order to capture the stream response due to intense and spatially-concentrated rainfall events. In winter the pressure transducer is maintained active with a time rate of 30 minutes so as to be ready to register in spring the stream response due to snowmelt. In the summer 2011, some precipitation, runoff, snow and spring water samples for isotopic analysis (?18O and ?2H) were collected aiming to better characterize the origin of subsurface water and the main sources to runoff. Preliminary results show ephemeral presence of runoff, mostly occurring during snowmelt (from May to early July) and after intense summer rainstorms. The lag-time from precipitation centroid to runoff peak (on the order of about 1 hour) is rather long for a very small and steep basin. This is likely due to the presence of fractured bedrock that creates a shallow, subsurface reservoir and increases the catchment response time. Isotopic data of water samples well reflect the precipitation signal indicating reduced evaporation processes during the transfer of the water input to the outlet. Moreover, the isotopic composition of streamflow is close to that of the sampled springs but less depleted than snowmelt samples, revealing a possible contribution to runoff of snowmelt water mixed with subsurface water previously stored in the system.

Cavalli, M.; Trevisani, S.; Marchi, L.; Penna, D.; Borga, M.; Dalla Fontana, G.

2012-04-01

246

Hydrological characteristics of the Czerniejówka river basin  

NASA Astrophysics Data System (ADS)

This paper is focused on an analysis of conditions of groundwaters occurrence in the Czerniejówka river basin. The paper also presents the outflow rate from the upper and middle course of the river, where the natural environment is only slightly influenced by human activity. The lower part of the catchment is under city impact, intensified since 1954, when the water intake Dziesi?ta has started exploitation of groundwater resources. The middle part of the catchment is influenced by exploitation of water resources in the water intake Wilczopole, since 1988. Ten-year (1979-1988) water gauge observations and discharge measurement and water levels in the upper and middle part of the catchment, in the period of documentation of water resources of the water intake Wilczopole, are the basis of analysis. The Czerniejówka river basin is under strong and diversified human impact. Two water intakes constructed in the catchment of the river assure the water for 40% of the city demand. Hydrogeological conditions, fissured rocks and low elevation of the water division, determine the possibilities of underground water flow from the left part of the catchment to the Bystrzyca river basin, which significantly influences the reduced water resources of the Czerniejówka river. Good permeability of rocks is favourable for retention of water that steadily inflows to the river channel. Surface runoff occurs sporadically, usually in the frozen ground period rather than in the summer, which determines the high share of the ground feeding in total runoff. Average specific runoff for the upper and middle part of the basin was estimated as 4.2 dm3·s-1·km-2 in the ten-year period. At present conditions of catchment land use and exploitation of Dziesi?ta and Wilczopole water intakes, the Czerniejówka river discharge will decrease with the only feeding from the upper part of the catchment. In dry periods, in the middle and lower course of the Czerniejówka river infiltration of river water to underground resources, as well as in the Skrzyniczanka river, will take place.

Michalczyk, Zdzis?aw; Bartoszewski, Stefan; G?owacki, S?awomir; Sposób, Joanna

2011-01-01

247

Climatic warming, glacier recession and runoff from Alpine basins after the Little Ice Age maximum  

Microsoft Academic Search

Records of discharge of rivers draining Alpine basins with between 0 and ˜70% ice cover, in the upper Aare and Rhône catchments, Switzerland, for the period 1894-2006 have been examined together with climatic data for 1866-2006, with a view to assessing the effects on runoff from glacierized basins of climatic warming coupled with glacier recession following the Little Ice Age

David N. Collins

2008-01-01

248

Climatic warming, glacier recession and runoff from Alpine basins after the Little Ice Age maximum  

Microsoft Academic Search

Records of discharge of rivers draining Alpine basins with between 0 and ?? 70% ice cover, in the upper Aare and Rhone catchments, Switzerland, for the period 1894-2006 have been examined together with climatic data for 1866-2006, with a view to assessing the effects on runoff from glacierized basins of climatic warming coupled with glacier recession following the Little Ice

David N. Collins

2008-01-01

249

TIN-based topographic modelling and runoff prediction using a basin geomorphic information system  

Microsoft Academic Search

A geographic information system in hydrological modelling, BGIS, Basin Geomorphic Information System is presented for topographic modelling of a river basin, and it is combined with a distributed rainfall-runoff simulation system. BGIS is a set of computer programs which (a) model natural landscapes using TIN-based DEMs, (b) partition a catchment taking into account the direction of water flow for dealing

Y. TACHIKAWA; T. TAKASAO

1996-01-01

250

Historical land use changes and their impact on sediment fluxes in the Balaton basin (Hungary)  

Microsoft Academic Search

Agricultural land use changes can influence soil erosion process. The objective of this study was to investigate impact of historical land use changes on soil erosion and sediment transport in the Kali Basin study area, a small catchment located in a national park at Lake Balaton, Hungary. The Kali Basin is of high landscape value where vine (Vitis spp.) growing

Gyozo Jordan; Anton van Rompaey; Peter Szilassi; Gabor Csillag; Chris Mannaerts; Tsehaie Woldai

2005-01-01

251

Capturing dominant runoff processes in a complex, heterogenous mesoscale catchment: integrating tracers and modelling  

NASA Astrophysics Data System (ADS)

Dominant hydrological processes in complex meso-scale catchments are strongly influenced by landscape characteristics such as topography, geology and soils. In this study, we examine differences in the hydrological response and how small scale processes integrate at larger scales in seven contrasting sub-catchments (21 km2 - 307 km2) of a large river basin (749 km2) in north east Scotland. We use hydrometric and tracer data in conjunction with GIS analyses and simple model applications. The catchment covers two contrasting geomorphological landscape units: a mountainous upland with distinct glacial features and underlying metamorphic bedrock, and a lowland unit with an extensive sandstone aquifer. Gran alkalinity and stream water chemistry are used as environmental tracers to identify major runoff sources and to assess how small scale processes are integrated at larger spatial scale. A multivariate analysis of tracer data, spatial catchment characteristics and runoff response is applied to delineate first order controls for hydrological behaviour. This is used as a basis to conceptualise dominant runoff processes at multiple spatial scales.

Capell, R.; Tetzlaff, D.; Soulsby, C.; Malcolm, I. A.; Hartley, A. J.

2009-12-01

252

Capturing dominant runoff processes in a heterogeneous mesoscale catchment: Integrating tracers and modelling  

NASA Astrophysics Data System (ADS)

Dominant hydrological processes in complex meso-scale catchments are strongly influenced by landscape characteristics such as topography, geology and soils. In this study, we examine differences in the hydrological response and how small scale processes integrate at larger scales in seven contrasting sub-catchments (21 km2 - 307 km2) of a large river basin (749 km2) in north east Scotland. We use hydrometric and tracer data in conjunction with GIS analyses and simple model applications. The catchment covers two contrasting geomorphological landscape units: a mountainous upland with distinct glacial features and underlying metamorphic bedrock, and a lowland unit with an extensive sandstone aquifer. Gran alkalinity and stream water chemistry are used as environmental tracers to identify major runoff sources and to assess how small scale processes are integrated at larger spatial scale. A multivariate analysis of tracer data, spatial catchment characteristics and runoff response is applied to delineate first order controls for hydrological behaviour. This is used as a basis to conceptualise dominant runoff processes at multiple spatial scales.

Capell, René; Tetzlaff, Dörthe; Soulsby, Chris; Malcolm, Iain; Hartley, Adrian

2010-05-01

253

Urban Catchment Models: A Brief Examination.  

National Technical Information Service (NTIS)

Guidelines for the use of various commonly available urban catchment models are provided in the report. The models described in this report include: Chicago Hydrologic Model; Road Research Laboratory Model; University of Cincinnati Urban Runoff Model; and...

F. O. Agyei K. Mahmood M. I. Haque

1981-01-01

254

Sewered Drainage Catchments in Major Cities.  

National Technical Information Service (NTIS)

The size distribution and number of sewered drainage catchments in San Francisco, Washington, D. C., Milwaukee, Houston, and Philadelphia are summarized to provide data for urban rainfall-runoff-water quality studies. The 4 cities are in 4 distinctly diff...

L. S. Tucker

1969-01-01

255

Wildife Water Catchment Construction in Nevada.  

National Technical Information Service (NTIS)

This technical note describes two artificial water catchment (guzzler) construction methods that are used in northern and southern Nevada. In northern Nevada, a standard guzzler unit is constructed, and a site is located in which to install it. In souther...

C. Stevenson W. R. Brighman

2003-01-01

256

Forested Water Catchments in a Changing Environment  

Microsoft Academic Search

\\u000a In the past, headwater catchments have often been studied to elucidate the effect of forests on the water cycle. This has\\u000a been of interest since centuries and we recall here this historical context. We review the quantitative effects found in numerous\\u000a studies around the world, especially those from paired-catchment experiments. As a rule, they indicate a lower water yield\\u000a of

Patrick Schleppi

257

A preliminary biogeochemistry-based quantification of primary productivity of end-Permian deep-water basin in Dongpan Section, Guangxi, South China  

Microsoft Academic Search

In this paper, the mean primary productivity of the Talung Formation in the deep-water basin (50–500 m depth) of Dongpan,\\u000a Guangxi, South China, was calculated, roughly ranging from 0.1 to 0.6 g C·m?2·day?1 on the basis of the content of the trace element Cu. Results showed that the primary productivity obtained was comparable\\u000a with the previously-reported data for the black

Yang Zhang; Weihong He; Qinglai Feng

2007-01-01

258

Preliminary report on fluid inclusions from halites in the Castile and lower Salado formations of the Delaware Basin, southeastern New Mexico. [Freezing-point depression  

Microsoft Academic Search

A suite of samples composed primarily of halite from the upper Castile and lower Salado Formations of the Permian Basin was selected from Waste Isolation Pilot Plant (WIPP) core for a reconnaissance study of fluid inclusions. Volume percent of these trapped fluids averaged 0.7% to 1%. Freezing-point depressions varied widely and appeared to be unrelated to fluid-inclusion type, to sedimentary

2010-01-01

259

Late Quaternary landscape evolution in the Kunlun Mountains and Qaidam Basin, Northern Tibet: A framework for examining the links between glaciation, lake level changes and alluvial fan formation  

Microsoft Academic Search

The Qaidam Basin in Northern Tibet is one of the largest hyper-arid intermontane basins on Earth. Alluvial fans, pediment surfaces, shorelines and a thick succession of sediments within the basin, coupled with moraines and associated landforms in the adjacent high mountain catchments of the Kunlun Mountains, record a complex history of Late Quaternary paleoenvironmental change and landscape evolution. The region

Lewis A. Owen; Robert C. Finkel; M. Haizhou; Patrick L. Barnard

2006-01-01

260

Runoff evolution according to land use change in a small Sahelian catchment  

NASA Astrophysics Data System (ADS)

Significant land use changes have been observed in West Africa, particularly in the Sahel region where climatic and demographic factors have led to a rise in cultivated areas, in recent decades. These changes caused strong modifications in the water cycle and in river regimes. By comparing the rainfall-runoff relationships for two periods (1991-1994 and 2004-2010) in two small neighbouring catchments (approx. 0.1 km2 each) of the Sahel, this study highlights the different hydrological consequences of land use change, particularly vegetation clearing and the consequent degradation of topsoil. Runoff increased in the upper basin, while it decreased in the lower basin, due to a strong increase in in-channel infiltration. Flood peak durations have become shorter in the downstream part of the catchment due to the huge increase of runoff water transmission losses within the gullies. Further study will consist of equipping one of the catchments with anti-erosion devices (mainly "half-moons" and terraces) in order to evaluate the influence of anti-erosion devices on runoff and suspended load.

Descroix, L.; Esteves, M.; Souley Yéro, K.; Rajot, J.-L.; Malam Abdou, M.; Boubkraoui, S.; Lapetite, J. M.; Dessay, N.; Zin, I.; Amogu, O.; Bachir, A.; Bouzou Moussa, I.; Le Breton, E.; Mamadou, I.

2011-02-01

261

Development of regionalisation procedures using a multi-model approach for flow simulation in an ungauged catchment  

NASA Astrophysics Data System (ADS)

Flow simulation in ungauged catchments is presently regarded as one of the most challenging tasks in surface water hydrology. Many of the ungauged catchments are located in the headwaters of rivers in mountainous regions of the world having enormous potential for sustainable water resource development. However, due to inaccessibility, rugged and inhospitable terrain, and historical lack of foresight concerning the need to have these headwaters adequately gauged, their potential is not readily realizable. Many downstream sites also suffer from non-availability of site-specific data as even in countries having extensive networks of gauged stations data may not be available at sites where these are most needed. As predictive tools for water resources, water quality, natural hazard mitigation and water availability assessment are generally data-driven, the lack of adequate hydrometric records poses difficult problems for planners, engineers, managers, and stake-holders alike. In this study, a methodology is developed for flow simulation in ungauged catchments using a regionalisation and multi-model approach involving a suite of rainfall runoff models and combination techniques. Daily observed hydrometeorological data for 12 French catchments are used for illustrating the procedures. Following a preliminary investigation of the regional homogeneity of that group of catchments, three regional flow simulation techniques are applied. Although all 12 catchments are gauged, initially each catchment is successively considered as being ungauged for the purpose of flow simulation in that catchment, their actual discharges being subsequently used for evaluating the performance of the flow estimation procedures for the catchment. The Nash-Sutcliffe efficiency index (R2) is used for assessing and ranking the relative performances of the regionalisation model couples to identify the most appropriate couple for the region. The final step of applying that couple to a truly ungauged (13th) catchment in the region is described. Results are presented and conclusions drawn on the efficacy of the regional-multi-model approach. Of the couples considered, the pooling method of regionalisation coupled with the conceptual soil moisture accounting and routing (SMAR) model is deemed to be the best for simulating flow in an ungauged catchment in the region.

Goswami, M.; O'Connor, K. M.; Bhattarai, K. P.

2007-02-01

262

Ring spacing of Mercurian multi-ring basins and basin ring formation  

NASA Astrophysics Data System (ADS)

Recent systematic mapping of Mercury has revealed many ancient and previously unrecognized multi-ring basins. The population of these basins now stands at 20, possibly is as large as 25, and includes at least 76 measurable rings. From the new data base, the authors present some systematics of basin ring spacing on Mercury, compare them with similar data for the Moon, and draw some preliminary conclusions on conditions of ring formation for basins on the terrestrial planets.

Pike, R. J.; Spudis, P. D.

1984-04-01

263

Streamflow Forecasts in Poorly Documented Basins from Meteorological Fields  

Microsoft Academic Search

This paper describes research undertaken in support of a project that seeks to enable the interpretation of predicted meteorological fields in terms of the streamflow in poorly documented catchments. The focus in this presentation is on addressing the issues involved in parameterizing and calibrating the hydrological model to do this in basins where available local data is limited. Hydrological modeling

E. M. Uribe; J. W. Shuttleworth; H. V. Gupta; S. L. Mullen; X. Zeng

2006-01-01

264

Urban and agricultural contribution of annual loads of glyphosate and AMPA towards surface waters at the Orge River catchment scale (France)  

Microsoft Academic Search

The general use of pesticides in the Orge Basin, located in the southern part of the Paris suburb (France), is damaging surface water quality. Consequently, an increase in the water supply costs is registered by the water supply agencies that are situated downstream the Orge confluence with the Seine River. In this catchment, high uses of glyphosate are registered for

Fabrizio Botta; Marc Chevreuil; Hélène Blanchoud

2010-01-01

265

Simulation of terrain and forest shelter effects on patterns of snow deposition, snowmelt and runoff over a semi-arid mountain catchment  

Microsoft Academic Search

In mountainous regions, topographic structure and vegetation control patterns of snow deposition, climate conditions, and snowmelt. A topographically distributed snow accumulation and melt model (ISNOBAL) was coupled to a wind field and snow redistribution model to simulate the development and ablation of the seasonal snow cover over a small mountainous catchment, the Reynolds Mountain East basin (0·38 km2) in southwestern

Danny Marks; Adam Winstral; Mark Seyfried

2002-01-01

266

Relating variations in runoff to variations in climatic conditions and catchment properties  

NASA Astrophysics Data System (ADS)

We use the Budyko framework to calculate catchment-scale evapotranspiration (E)and runoff (Q) as a function of two climatic factors, precipitation (P) and evaporative demand (Eo = 0.75 times the pan evaporation rate), and a third parameter that encodes the catchment properties (n) and modifies how P is partitioned between E and Q. We use examples from the Murray-Darling Basin in Australia, and elsewhere, to examine the effects on run-off of perturbations to the underlying parameters. We include an examination of projections based on Intergovernmental Panel on Climate Change AR4 climate model output. We conclude that the modern version of the Budyko framework is a useful tool for making simple and transparent estimates of changes in water availability.

Farquhar, Graham; Sun, Fubao; Roderick, Michael

2013-04-01

267

Pervious and impervious runoff in urban catchments  

Microsoft Academic Search

Rainfall and runoff depths were examined for 763 storms on 26 urban basins located in 12 countries. For 17 of the basins, impervious surfaces were the major contributors to storm runoff. These basins were generally smaller than 25 ha and had small to medium storms in the data set. Nine basins had significant amounts of runoff from pervious as well

M. J. BOYD

268

Controls on old and new water contributions to stream flow at some nested catchments in Vermont, USA  

NASA Astrophysics Data System (ADS)

Factors controlling the partitioning of old and new water contributions to stream flow were investigated for three events in four catchments (three of which were nested) at Sleepers River Research Watershed in Danville, Vermont. In the 1993 snowmelt period, two-component isotopic hydrograph separations showed that new water (meltwater) inputs to the stream ranged widely from 41 to 74%, and increased with catchment size (41 to 11 125 ha) (with one exception) and with open land cover (0-73%). Peak dissolved organic carbon concentrations and relative alkalinity dilution in stream water ranked in the same order among catchments as the new water fractions, suggesting that new water followed shallow flow paths. During the 1994 snowmelt, despite similar timing and magnitude of melt inputs, the new-water contribution to stream flow ranged only from 30 to 36% in the four catchments. We conclude that the uncommonly high and variable new water fractions in streamwater during the 1993 melt were caused by direct runoff of meltwater over frozen ground, which was prevalent in open land areas during the 1993 winter. In a high-intensity summer rainstorm in 1993, new water fractions were smaller relative to the 1993 snowmelt, ranging from 28 to 46%, but they ranked in the identical catchment order. Reconciliation of the contrasting patterns of new-old water partitioning in the three events appears to require an explanation that invokes multiple processes and effects, including: 1.topographically controlled increase in surface-saturated area with increasing catchment size;2.direct runoff over frozen ground;3.low infiltration in agriculturally compacted soils;4.differences in soil transmissivity, which may be more relevant under dry antecedent conditions. These data highlight some of the difficulties faced by catchment hydrologists in formulating a theory of runoff generation at varying basin scales.

Shanley, James B.; Kendall, Carol; Smith, Thor E.; Wolock, David M.; McDonnell, Jeffrey J.

2002-02-01

269

Modelling runoff using optical satellite remote sensing data in a high mountainous alpine catchment of Italy  

NASA Astrophysics Data System (ADS)

Development of hydrological models for seasonal and real-time runoff forecast in rivers of high alpine catchments is useful for management of water resources. The conceptual models for this purpose are based on a temperature index and/or energy budget and can be either lumped or distributed over the catchment area. Remote sensing satellite data are most useful to acquire near real-time geophysical parameters in order to input to the distributed forecasting models. In the present study, integration of optical satellite remote sensing-derived information was made with ground meteorological and hydrological data, and predetermined catchment morphological parameters, to study the feasibility of application of a distributed temperature index snowmelt runoff model to one of the high mountainous catchments in the Italian Alps, known as Cordevole River Basin. Five sets of Landsat Multispectral Scanning System (MSS) and Thematic Mapper (TM) computer-compatible tapes (CCTs) were processed using digital image processing techniques in order to evaluate the snow cover variation quantitatively. Digital elevation model, slope and aspect parameters were developed and used during satellite data processing. The satellite scenes were classified as snow, snow under transition and snow free areas. A second-order polynomial fit has been attempted to approximate the snow depletion and to estimate daily snow cover areal extent for three elevation zones of the catchment separately. Model performance evaluation based on correlation coefficient, Nash-Sutcliffe coefficient and percentage volume deviation indicated very good simulation between measured and computed discharges for the entire snowmelt period. The use of average temperature values computed from the maximum and minimum temperatures into the model was studied and a suitable algorithm was proposed.

Narayana Swamy, A.; Brivio, Pietro Alessandro

1997-09-01

270

Impact of Climate Change on Hydrological Regimes and Water Resources Management in the Rhine Basin  

Microsoft Academic Search

The International Commission for the Hydrology of the Rhine basin (CHR) hascarried out a researchproject to assess the impact of climate change on the river flow conditionsin the Rhine basin. Along abottom-up line, different detailed hydrological models with hourly and dailytime steps have beendeveloped for representative sub-catchments of the Rhine basin. Along atop-down line, a water balancemodel for the entire

H. Middelkoop; K. Daamen; D. Gellens; W. Grabs; J. C. J. Kwadijk; H. Lang; B. W. A. H. Parmet; B. Schädler; J. Schulla; K. Wilke

2001-01-01

271

Hydrologic flowpaths and biogeochemical cycles in the subalpine Como Creek catchment, Colorado Front Range, USA  

NASA Astrophysics Data System (ADS)

An outstanding question for snowmelt-dominated watersheds of the western US are the responses of biogeochemical processes to two major drivers of environmental change: directional changes in climate and increasing dissolved inorganic nitrogen (DIN) deposition in wetfall. In the Colorado Front Range, atmospheric deposition of DIN has increased several-fold in the last 25 years. In response, nitrate concentrations at the alpine Green Lakes 4 (GL4) catchment have increased from 1985 to 2009 by 0.27 ?eq L-1 yr-1. In contrast, we see no directional change in either nitrate concentrations or fluxes in the subalpine Como Creek catchment. We hypothesize that differences in surface/groundwater interactions result in the differing behavior of stream nitrate between the alpine and subalpine catchments that are receiving similar amounts of DIN from atmospheric deposition. For both basins we sampled precipitation, snowpack, snowmelt, surface water, and subsurface waters. All water samples are analyzed for geochemical, nutrient and isotopic (?18O, ?D) composition. Stream chemistry data from the last ten years at Como Creek show increases in nitrate concentration during baseflow conditions and then a sharp decline during snowmelt. In contrast, in the alpine basin there is sharp increase in surface water nitrate during snowmelt. Hydrograph separation at the alpine GL4 using end member mixing analysis (EMMA) shows that stream flow is a mixture of three components, groundwater, talus, and new snowmelt that each contribute to roughly a third of discharge, with talus flow supplying the majority of nitrate. In contrast, and somewhat surprisingly, EMMA shows that for the subalpine Como Creek basin, annual streamflow is a mixture of only two components, groundwater and new snowmelt. During snowmelt the groundwater and snow contributions are nearly equal and subsurface flows dominate the remainder of the year. Newly installed piezometers at Como Creek provide evidence that the basin is largely a losing reach during snowmelt, with water levels in the piezometers increasing 5-7 m. After peak snowmelt however, Como Creek becomes a gaining stream, with piezometer levels dropping. Thus, both EMMA and piezometers show that surface-groundwater interactions are tightly coupled during snowmelt, with snowmelt at Como first replenishing the subsurface water deficit and increasing groundwater levels before contributing to discharge. Thus, in contrast to the alpine GL4 basin, DIN released in snowmelt is assimilated belowground as snowmelt infiltrates the subsurface in the subalpine basin. Interestingly, at the subalpine Como Creek basin, isotopic and geochemical solute concentrations undergo shifts during periods of winter baseflow prior to snowmelt. In winter much of the stream is frozen and we hypothesize that cryo-concentration of solutes and fractionation of isotopes may influence the concentrations of winter stream samples.

Cowie, R. M.; Williams, M. W.; Zeliff, M. M.; Parman, J.

2011-12-01

272

Flash flood modelling for ungauged catchments  

NASA Astrophysics Data System (ADS)

Flash flood is a very intense and quick hydrologic response of a catchment to rainfall. This phenomenon has a high spatial-temporal variability as its generating storm, often hitting small catchments (few km2). Data collected by (Gaume et al. 2009) about 500 flash floods over the last 50 years showed that they could occur everywhere in Europe and more often in the Mediterranean regions, Alpine regions and continental Europe. Given the small spatial-temporal scales and high variability of flash floods, their prediction remains a hard exercise as the necessary data are often scarce. Flash flood prediction on ungauged catchments is one of the challenges of hydrological modelling as defined by (Sivapalan et al. 2003). Several studies have been headed up with the MARINE model (Modélisation de l'Anticipation du Ruissellement et des Inondations pour des évèNements Extrêmes) for the Gard region (France), (Roux et al. 2011), (Castaings et al. 2009). This physically based spatially distributed rainfall runoff model is dedicated to flash flood prediction. The study aims at finding a methodology for flash flood prediction at ungauged locations in the Cévennes-Vivarais region in particular. The regionalization method is based on multiple calibrations on gauged catchments in order to extract model structures (model + parameter values) for each catchment. Several mathematical methods (multiple regressions, transfer functions, krigging…) will then be tested to calculate a regional parameter set. The study also investigates the usability of additional hydrologic indices at different time scales to constrain model predictions from parameters obtained using these indices, and this independently of the model considered. These hydrologic indices gather information on hydrograph shape or catchment dynamic for instance. Results explaining global catchments behaviour are expected that way. The spatial-temporal variability of storms is also described through indices and linked with hydrograph shape descriptors in order to constrain model at ungauged locations. In a multi scale point of view, regional characteristics about catchments geomorphology or rainfall fields' statistics should provide useful insight to find pertinent hydrologic response indices. These considerations with physically based distributed modelling may bring better understanding on flash floods generating mechanisms and catchment responses.

Garambois, P.-A.; Roux, H.; Larnier, K.; Dartus, D.

2012-04-01

273

In Lieu of the Paired-Catchment Approach - Hydrologic Model Change Detection at the Catchment Scale  

NASA Astrophysics Data System (ADS)

Knowledge of the effects of forest management on hydrology primarily comes from paired-catchment studies conducted world-wide. While this approach has been useful for discerning changes in small experimental catchments and has contributed fundamental knowledge of the effects of forest and natural resources management on hydrology, results from experimental catchment studies exhibit temporal variability, have limited spatial inference, and lack insight into internal catchment processes. To address these limitations, traditional field experiments can be supplemented with numerical models to isolate the effects of disturbance on catchment behavior. Outlined in this study is an alternative method of change detection for daily time-series streamflow that integrates hydrologic modeling and statistical change detection methods used to discern the effects of contemporary forest management on the hydrology of western Oregon Cascades headwater catchments. In this study, a simple rainfall-runoff model was used to generate virtual reference catchments using attributes that reflect streamflow conditions absent of forest disturbance. Streamflow was simulated under three levels of model uncertainty using GLUE and were used to construct generalized least squares regression models to discern changes in hydrologic behavior. By considering processes within a single experimental catchment rather than the two spatially explicit catchments used in traditional paired experiments, it was possible to reduce unexplained variation and increase the likelihood of correctly detecting hydrologic effects following forest harvesting. In order to evaluate the stability of the hydrologic and statistical models and catchment behavior over time, the change detection method was applied to a contemporary reference catchment. By applying the change detection model to reference catchments, it was possible to eliminate unexpected variation as a cause for detected changes in observed hydrology. Further, it was possible to attribute increased streamflow to forest management with greater certainty. Shown is the importance and necessity of coupling hydrologic modeling studies with reference catchments in order to evaluate model performance and reduce false detections from statistical models. The proposed method appears to be a useful alternative to change detection using highly variable daily streamflow.

Zegre, N. P.

2009-05-01

274

What makes catchment management groups "tick"?  

PubMed

The work of catchment management groups throughout Australia represents a significant economic and social investment in natural resource management. Institutional structures and policies, the role of on-ground coordinators, facilitation processes, citizen participation and social capital are critical factors influencing the success of catchment management groups. From a participant-researcher viewpoint, this paper signposts research directions and themes that are being pursued from the participant/coordinator, catchment group, and lead government/non-government agency perspective on the influence of these factors on the success of a catchment management group in the Pumicestone Region of Southeast Queensland, Australia. Research directions, themes and discussion/reflection points for practitioners include--the importance of understanding milieu; motivation; success; having fun; "networking networks"; involvement of "nontraditional" stakeholders; development of stakeholder/participant partnerships; learning from other practitioners; methods of stakeholder/participant representation; evaluation; the need for guiding principles or philosophy; the equivalence of planning, implementation, evaluation, and resourcing; catchments as fundamental units of Nature; continuity of support for groups; recognising a new role for government; working with existing networks; and the need for an eclectic approach to natural resource management. PMID:11424936

Oliver, P

2001-01-01

275

Towards an Objective Model of Catchment Hydrology  

NASA Astrophysics Data System (ADS)

The internal structure of catchment hydrologic models remains one of the most subjective elements of coupled hydrologic and biogeochemical models, despite the recognized sensitivity of predictions to the chosen model structure. Hillslope hydrologic studies indicate the high degree of complexity in transport processes at this spatial scale (e.g., variably saturated media, macropore-dominated transport). How can the complexities observed at the hillslope scale be translated into a general catchment model with modest data requirements, yet retain structure that is defined objectively by data? Observations from a hillslope trench study at Panola Mountain Research Watershed (GA, USA) suggest that residence time of water within a landscape unit may be the single most important physical characteristic determining the observed chemistry for a given setting. We contrast the chemistry of the saturated zone in the hillslope with stream chemistry at three catchments that exhibit a range of residence times. Stream chemistry at the catchment with the shortest residence time is most similar to hillslope chemistry, suggesting that a simple model structure, with few reservoirs, may be appropriate at this site. By contrast, at the site with the longest residence time, the greatest difference is observed between stream and hillslope chemistry, suggesting that more reservoirs are needed to model the catchment. The organizing principle in designing the structure of coupled hydrologic and biogeochemical models is to choose a model structure that reproduces the residence times matching those of the rate constants of critical biogeochemical processes.

Hooper, R. P.; McDonnell, J. J.; Hjerdt, K. N.; McGlynn, B. L.

2001-12-01

276

Influence of Catchment Scale and Landscape Controls on Runoff Sources and Mean Residence Times in Montane Watersheds  

Microsoft Academic Search

The influence of catchment scale and landscape controls on hydrological sources and mean residence times were assessed in nested sub-basins of 3 separate montane watersheds (30-230km2) in northern Scotland. Geochemical and isotopic tracers were used to carry out chemical hydrograph separations to quantify the relative contribution of different hydrological sources to annual runoff and estimate mean residence times in 24

C. Soulsby; D. Tetzlaff; S. Waldron; S. Dunn

2005-01-01

277

Predicting faecal indicator fluxes using digital land use data in the UK's sentinel Water Framework Directive catchment: The Ribble study  

Microsoft Academic Search

The Ribble drainage basin is the single UK sentinel study area chosen for examining the implementation of the EU Water Framework Directive (WFD 20\\/60\\/EC). The study which has generated the data for this paper was initiated to quantify ‘catchment-derived’ fluxes of faecal indicators originating from both point and diffuse sources to inform the competent authorities on the potential for, and

David Kay; Mark Wyer; John Crowther; Carl Stapleton; Michael Bradford; Adrian McDonald; Jon Greaves; Carol Francis; John Watkins

2005-01-01

278

Estimating Post-Wildfire Catchment Sediment Budgets, South Fork Salmon River, Idaho  

NASA Astrophysics Data System (ADS)

Fire is an important agent of hydrological, biological and geomorphological change in Idaho forests. Vegetation mortality, loss of root strength, and increased soil hydrophobicity contribute to increase post-fire hillslope erosion rates. Over longer time scales, warmer, drier periods are linked to more frequent forest fires, which in turn helps to drive long-term sediment flux. Increasing annual temperature and drought occurrence associated with current climate change have the potential to amplify forest fire frequency and severity, and thus to increase hillslope erosion rates. Hillslope erosion rates affect forest vegetation recovery and the sediment supplied to channels, which impacts aquatic habitat and downstream reservoir longevity. Severe fires in 2007 on the Payette National Forest, Idaho, affected much of the South Fork Salmon River basin. This research estimates the quantity of sediment delivered to the channel of a small catchment within the South Fork Salmon River basin. For this event, sediment volumes delivered by landslides and debris flows were measured using ground surveys, and overland flow input is being measured using 210Pb and 137Cs soil profiles. Our results suggest that in the absence of major landslides or debris flows, the contribution of overland flow may be a major component of post-wildfire sediment budgets in steep alluvial valleys. Basin-wide disturbances like the 2007 fires have the potential to contribute substantially to long-term catchment-scale sediment budgets, and may occur more frequently as an effect of current climate change.

Perreault, L. M.; Yager, E. M.; Aalto, R. E.

2009-12-01

279

Spatial variability in river-catchment interaction: Combining radon measurements and salt tracer experiments  

NASA Astrophysics Data System (ADS)

Hydrological modeling is commonly based on a discharge calibration. This approach, however, is often insufficient to properly reproduce conditions that exceed the range of calibrated conditions and is therefore inadequate for predicting reactions to a changing environment. Small headwater catchments are often characterized by manifold morphological attributes (e.g. changes in river course, variable depth to bedrock...) and complex topography, resulting in potentially high spatial variability of river-catchment interactions. Such systems are often poorly represented by simple rainfall runoff models. For that reason, increasing effort is taken to investigate the functional organization of river catchments. From a river's point of view, the first questions to be solved are: How variable is river-catchment interaction in space? Where along the river do we find exfiltrating or infiltrating conditions? Which pathway did the water take before entering the stream? To investigate these questions we used an approach that combined salt tracer experiments with Radon-222 (referred to as radon) measurements. Radon is a natural occurring radionuclide that is accumulated in water traveling through saturated bedrock and mineral material. In contact with air the inert noble gas degases quickly and is thus a reliable environmental tracer for groundwater-surface water interactions. Measurements were carried out at a 650 m long tributary of the Colpach, which is part of the Attert basin in Luxembourg. In the first phase of the experiment radon was sampled every 50 m along the tributary. At the same time, salt tracer experiments were conducted over 100 m sections, providing information on discharge at the up- and downstream end of each 100 m section, absolute gain and loss along the 100 m section and travel times between all radon sampling sites. In the second phase, three sections where investigated in more detail. The chosen sections were divided according to changes of morphological attributes like river course (e.g. braided, meandering, straight), changes in stream bed substrate (e.g. loam, gravel, bedrock) or certain landmarks (e.g. ephemeral tributaries, river widening). Radon was sampled at the beginning and end of every subsection and the travel time between every radon sampling site was determined with salt tracer injections. Based on this information we accomplished a simple mass balance calculation to distinguish the respective groundwater and event water components of the measured gain and loss along all river sections. The results show that there is a high spatial variability in discharge quantity and composition down to the scale of few meters. With regard to the functional organization of river catchments, these observations imply that the interpretation of both, discharge dynamics as well as catchment processes requires a thorough understanding of the spatially varying connectedness between river, catchment and groundwater.

Angermann, Lisa; Tecklenburg, Christina; Blume, Theresa

2013-04-01

280

What is the Source? Post-glacial sediment flux from the Waipaoa Catchment, New Zealand  

NASA Astrophysics Data System (ADS)

In the Waipaoa, and for much of the eastern North Island, the shift from the last glacial coldest period to the current interglacial climatic regime resulted in Late Pleistocene-Holocene catchment-wide channel incision (Berryman et al., 2000; Litchfield and Berryman, 2005). Only ~25% of the total post 18 ka sediment yield for the Waipaoa Catchment can be accounted for by channel incision, one of the most widespread and most effective erosive processes in the catchment (Orpin et al., 2006; Marden et al., 2008). We find that deep-seated landslides, which are pervasive, cannot make up this apparent source area sediment deficit. This presents a challenge to our current understanding of the Waipaoa Sedimentary System. New high resolution topographic data sets (lidar and photogrammetry) combined with tephrochronology and field mapping have enabled us to approximate the sediment flux from post 18 ka deep-seated landslides. The sediment delivered to the offshore sink from these upper Waipaoa landslides is likely to be less than 20% of the sediment volume calculated for channel incision. A further GIS analysis of the ~2500 km2 Waipaoa catchment using work from Crosby and Whipple (2006) delineating relict topography and Marden et al. (2008) accounting for river incision and slopes stabilized behind terrace remnants indicates that only about half of the available catchment area could have contributed additional large volumes of sediment to the offshore post 18 ka sink. The presence of tephra cover older than 18 ka on landforms ranging from flat ridgelines to steep (>30 degree) slopes in this remaining terrestrial source area suggests that it has not been eroded en mass. The apparent source deficit remains even though many of the major erosive processes available to fill this deficit have been studied and the potentially contributing catchment area is dramatically reduced by these studies. This analysis raises questions about erosive processes and our ability to balance large scale sediment budgets. Does costal erosion contribute a significant volume to the offshore sink? Was sediment from other catchments trapped in the Poverty Bay postglacial shelf basin? Are the uncertainties in any of these source and sink calculations large enough that the previous questions are essentially irrelevant? We believe that it is an achievable goal to account for the major processes that generate sediment in the Waipaoa Sedimentary System and that this budget tuning can inform our understanding of active landscapes.

Bilderback, E. L.; Pettinga, J. R.; Litchfield, N. J.; Quigley, M.; Marden, M.

2011-12-01

281

The Humber catchment and its coastal area: from UK to European perspectives.  

PubMed

The present water quality of the Humber rivers and coastal zone depends on a complex interplay of factors, including physical ones, such as the underlying geology, which influences soil type, climatic ones, such as the rainfall, which influences runoff, socio-economic ones, which influence present-day human activities in the catchment, and the legacy of former activities, such as contaminated sediments from mining. All of these factors affect the fluxes of nutrients and other contaminants to the rivers and coastal zone. The Water Framework Directive (WFD) requires the production of a river basin management plan intended to lead to the achievement of good chemical and ecological status for all water bodies in the catchment over the next two decades. This paper provides an overview of the current environmental and socio-economic state of the Humber catchment and coastal zone, and broadly examines how socio-economic drivers affect the fluxes of nutrients and contaminants to the coastal zone, using the driver-pressure-state-impact-response (DPSIR) approach. This is followed by an overview of future research, describing the use of scenarios to simulate future fluxes and provide a consistent framework to evaluate potential policies to improve water quality in the estuary. The Humber catchment is one of eight case studies within a European research project, EUROCAT (EVK1-CT-2000-00044), which aims to achieve integrated catchment and coastal zone management by analysing the response of the coastal sea to changes in fluxes of nutrients and contaminants from the catchments. For the Humber case study, the research focuses on the fluxes of two nutrient elements, N and P, and four metal contaminants, As, Cu, Pb and Zn. The project requires the integration of scientific and socio-economic approaches, bringing together quantitative environmental data garnered for individual river catchments and coastal zones in previous research programmes, and local and regional socio-economic data, to aid decision-makers in their search for integrated and sustainable coastal zone management strategies. PMID:14499525

Cave, R R; Ledoux, L; Turner, K; Jickells, T; Andrews, J E; Davies, H

2003-10-01

282

Temporal variation in sediment budget components for a small incised upland catchment in southeastern Australia  

NASA Astrophysics Data System (ADS)

Temporal variation in process rates, sediment storage and exports can result in substantial changes to components of catchment sediment budgets over both short and long timescales. Quantifying the magnitude of temporal change in sediment budgets is important for interpretation of current and future processes and in understanding landform change. In this study, we develop a fine (900 m) plateau, with channel incision extending along the valley floor to mid-catchment. Land use is predominantly sheep and cattle grazing of pasture, with unrestricted stock access to channels. Various process-based techniques were used to examine temporal variation in sediment budget components over seasonal timescales (3-4 monthly) for a period of nearly two years. This included monitoring of hillslope and channel bank erosion, channel cross-sectional change, and suspended sediment output in conjunction with USLE-based hillslope erosion modelling and sediment source tracing using 137Cs and 210Pbex. Over the total study period, the sediment budget developed from these datasets indicated channel bank erosion accounted for an estimated 80% (41.6 t) of total sediment inputs. Valley floor and in-channel sediment storage represented 53% of total inputs and the remaining 47% was exported from the catchment. Temporal variation in catchment suspended sediment exports was largely dependent on the dynamics of sediment supply and storage within eroding channels. This was reflected in the sediment delivery ratios (SDR) for individual measurement intervals, which ranged from 1 to 153%. Bank sediment supply during low rainfall periods was reduced but subaerial processes - including rainsplash and sheetwash, freeze-thaw, and stock trampling effects - continued delivering sediment to channels, resulting in net accumulation on the channel bed with insufficient flow to transport this material to the catchment outlet. Following the higher flow period in spring of the first year of monitoring, sediment supplied to channels during the 3-month measurement interval was removed as well as an estimated 72% of the sediment accumulated on the channel bed since the start of the study period. The variation in rainfall patterns, pasture vegetation growth, and antecedent soil moisture with seasons and drought conditions contributed to observed hydrological response and sediment flux patterns. Given the seasonal and drought-dependent variability in sediment storage and delivery, the period of monitoring may have an important influence on the overall SDR and interpretation of sediment transfer through catchments. This study also highlighted the potential significance of sediment dynamics in channels for determining contemporary sediment yields from small gullied upland catchments in southeastern Australia, which are widespread in parts of the southern Murray-Darling Basin and appear to represent an important source of fine sediment delivered to lowlands.

Smith, Hugh; Dragovich, Deirdre

2010-05-01

283

Towards the determination of an optimal scale for stormwater quality management: micropollutants in a small residential catchment.  

PubMed

Stormwater and atmospheric deposits were collected on a small residential urban catchment (0.8 ha) near Paris in order to determine the levels of certain micropollutants (using a preliminary scan of 69 contaminants, followed by a more detailed quantification of PAHs, PCBs, alkylphenols and metals). Atmospheric inputs accounted for only 10%-38% of the stormwater contamination (except for PCBs), thus indicating substantial release within the catchment. On this small upstream catchment however, stormwater contamination is significantly lower than that observed downstream in storm sewers on larger adjacent urban catchments with similar land uses. These results likely stem from cross-contamination activity during transfers inside the sewer system and underscore the advantages of runoff management strategies at the source for controlling stormwater pollutant loads. Moreover, it has been shown that both contamination levels and contaminant speciation evolve with the scale of the catchment, in correlation with a large fraction of dissolved contaminants in upstream runoff, which differs from what has been traditionally assumed for stormwater. Consequently, the choice of treatment device/protocol must be adapted to the management scale as well as to the targeted type of contaminant. PMID:22204938

Bressy, A; Gromaire, M-C; Lorgeoux, C; Saad, M; Leroy, F; Chebbo, G

2011-12-13

284

Nitrogen and Carbon Cycling in Deforested and Pristine Upland (2400m) Forest Catchments in the Peruvian Andes  

NASA Astrophysics Data System (ADS)

Nitrogen and carbon cycling were examined within two upland (2400m) forest catchments in the Peruvian Andes. One catchment was partially deforested within the last 3 years, while the other has remained untouched. Tracer amended samples were analyzed to determine the pathways and rates of nitrogen cycling in streams draining each catchment. Both streams exhibited very low inorganic nitrogen levels, on the order of 1 to 2 uM. A large percentage (>1/3) of the total fixed nitrogen flux from these systems was in the form of particulates. Preliminary results suggest a very high rate of nitrogen cycling in these systems. Isotopic measurements of plant samples from both catchments also suggest that these forests are highly efficient in trapping and using atmospheric nitrogen sources. The partially deforested catchment had significantly more species using C4 and CAM carbon fixation pathways. Leaf litter from both streams and leaves from trees in the area were also analyzed for carbon and nitrogen isotopes to compare and contrast nitrogen and carbon cycling between the two sites. This and other data to be presented suggest that deforestation has subtle but significant effects upon the ability of tropical upland forests to retain and use nutrients.

Townsend-Small, A.; Haberer, J.; McClain, M.; Ramos, O.; Gardner, W.; McCarthy, M.; Brandes, J.

2001-12-01

285

Analyzing Catchment Hydrologic Function through Process-based Behavioral Modeling  

NASA Astrophysics Data System (ADS)

Catchment classification should be based on the understanding of how climatic conditions and catchment characteristics control catchment function (partitioning, storage, and release). Such understanding can come from the reconciliation of data and theory, requiring both top-down and bottom-up approaches. While a top-down approach can be used to classify catchments by constructing groups of hydrologically similar catchments, a bottom-up approach is needed to further understand the internal functional differences of catchments within each group. In this study a parsimonious process based model was developed to analyze catchment function across climatic gradients. The soil moisture hillslope-storage Boussinesq Catchment Model (SM-hsB) simulates the diurnal dynamics of the energy and water fluxes at the land surface, vertical recharge/capillary rise to/from the water table, the lateral movement of water from the unconfined hillslope aquifers into the channel network, and the routing of surface water to the catchment’s outlet. SM-hsB was used to define behavioral parameter sets for 12 catchments from the MOPEX database. Comparison of these parameter sets provides insight on how catchments functions interact to produce distinctive hydrologic response. These behavioral models were then used to perform “virtual experiments”. For example, catchments were “geographical relocated” to analyze their filtering effect on different climatic signals. Geology, geomorphology, and vegetation descriptors of the catchment were shuffled, providing interesting insights on their relative roles on catchment responses. Results of these experiments complement an empirical analysis of catchment responses, climate drivers and landscape characteristics (Sawicz et al., this session).

Carrillo, G. A.; Troch, P. A.; Sivapalan, M.; Wagener, T.; Sawicz, K. A.

2010-12-01

286

Mixed Groundwater Ages in a Small Alpine Catchment  

NASA Astrophysics Data System (ADS)

Groundwater in alpine headwater catchments provides a year-round water source that supplies residential and recreation development, and sustains riparian and aquatic ecosystems with stream baseflow. The age of groundwater in these systems has implications for predicting the impact of climate changes that may include an increase in the rain to snow ratio, an earlier onset of snowmelt, and potentially a decrease in total precipitation. We find a wide range of groundwater residence times in a small (22 km2), high-altitude (1890 to over 2700 meters above MSL) catchment located in the Sierra Nevada mountains near Lake Tahoe. The Olympic Valley groundwater basin consists of alluvial valley fill on top of fractured bedrock, and is accessible through numerous monitoring and production wells. Olympic Valley groundwater samples fall into three groupings: 1)samples with very young mean apparent ages and little pre-modern water, which have detectable 35S and no significant tritiogenic 3He, 2)samples produced from wells screened near the alluvium/bedrock interface, which have a component of relatively young, tritiated water mixed with older, pre-modern water containing radiogenic 4He, and 3)samples from wells near a recently active fault that have a smaller component of young water mixed with older water and magmatic fluids. The aquifer is dominated by the young (<1 year apparent age) water, and it is likely this component that predominantly drives stream baseflow that is observed during the snowmelt season using 222Rn and fiber-optic distributed temperature sensing, and is visible as sustained pools along the stream during the dry season. It is also this youngest component that is most vulnerable to changes in precipitation behavior. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Singleton, M. J.; Moran, J. E.; Esser, B.; Hatch, C. E.; Tyler, S. W.; Cox, C.

2009-12-01

287

Influence of Catchment Scale and Landscape Controls on Runoff Sources and Mean Residence Times in Montane Watersheds  

NASA Astrophysics Data System (ADS)

The influence of catchment scale and landscape controls on hydrological sources and mean residence times were assessed in nested sub-basins of 3 separate montane watersheds (30-230km2) in northern Scotland. Geochemical and isotopic tracers were used to carry out chemical hydrograph separations to quantify the relative contribution of different hydrological sources to annual runoff and estimate mean residence times in 24 individual catchments at scales ranging from 0.9km to 230km2. Mean annual groundwater contributions varied between 23 and 54% of annual runoff, and mean residence times varied between 83 days and 443 days. A GIS was used for watershed analysis to assess the relative importance of landscape controls on hydrological sources and residence times. Neither of these hydrological descriptors exhibited significant correlations with catchment scale. Both were influenced by various topographic indices (eg mean slope and flowpath length), but were most strongly related to catchment soil cover mapped using the UK HOST (Hydrology Of Soil Types) national digital data base. Soils could be sub-divided between more hydrologically "responsive" montane soils (eg peats, regosols, and gleysols), which generate storm runoff by overland flow and shallow subsurface storm flow and more "free-draining" soils (eg podsols and inceptisols) that facilitate groundwater recharge. For the 24 catchments, the percentage cover of "responsive soils" was negatively correlated with groundwater contributions to annual flows were (r2 0.58, p <0.0001) and mean residence times (r2 0.82, p<0.0001). The study shows that accurate digital soil maps can provide excellent insights into hydrological functioning in catchments at a range of scales in montane environments. Despite their significance in water resource management as river headwaters, such catchments are often remote and logistically difficult to instrument, particularly at large scales. As soils integrate the effects of heterogeneities in catchment topography, geology, climate and vegetation, the paper will stress that soil maps have considerable potential for rapid impact assessment and modelling studies in ungauged basins in montane areas.

Soulsby, C.; Tetzlaff, D.; Waldron, S.; Dunn, S.

2005-12-01

288

Characterization and cartography of topsoil hydraulic properties in a French mountainous peri-urban catchment  

NASA Astrophysics Data System (ADS)

Due to the increase of urbanization and modification of agricultural practices, peri-urban areas experiment a quick change in land use. The impact of such change on the catchment hydrological cycle must be quantified. To achieve this goal, distributed hydrological models offer the ability to take into account land use change, and more specifically its effect on surface infiltration capacity. A distributed assessment of infiltration properties and their variability at the catchment scale is thus of great importance if accurate simulation of the water balance are expected on such catchments. This paper presents a field campaign conducted in a 7 km2 peri-urban catchment, located in the "Mont du Lyonnais" area, close to the city of Lyon (France) in order to document the topsoil hydraulic properties. The sampling strategy was set up in order to sample the largest number of soil/land use combinations. The locations were chosen from a GIS analysis based on the overlapping of the pedology and land use maps, and accessibility consideration. At each location, two types of infiltration tests were performed: infiltration tests under suction using mini-disk infiltrometers and single ring infiltration tests under positive head. Three replicates were performed for each method. Particle size data and organic matter analysis were also conducted at each location. Results will be discussed in terms of soil hydraulic properties and particle size data statistics. Relationship with external factors such as pedological unit, land use, slope, texture will be explored. Preliminary results show that forest and pasture soils exhibit the highest hydraulic conductivity and sorptivity. In order to provide models with values at the modelling unit scale (field and/or sub-catchment scale), existing pedotransfer function will be assessed and if necessary calibrated using the local measurements. Finally a methodology for the cartography of the soil hydraulic properties will be proposed.

Gonzalez-Sosa, E.; Braud, I.; Gonzalez-Sosa, E.; Dehotin, J.; Branger, F.; Lagouy, M.

2009-04-01

289

Medium to long-term impacts of forest fires on slope to catchment-scale processes under current and future climate  

NASA Astrophysics Data System (ADS)

Forest wildfires can have important impacts on hydrological and soil erosion processes in burnt areas due to a variety of changes to soil properties and vegetation cover. The relevance of these impacts varies with wildfire characteristics, post-fire rainfall regime, and pre- and post-fire land management. The complex interactions between the various factors and processes have been one of the major obstacles to assessing wildfire impacts, particularly at larger spatial scales and over medium to long-term periods. This presentation will show ongoing research on a forested region in north-central Portugal, the Vouga river basin, aiming at: (i) quantifying medium and long-term impacts of wildfires, and (ii) estimating the impacts of climate change on wildfire regimes and assess their implications in terms of hydrological and soil erosion processes, and land degradation in general. The focus will be in the methodology and some preliminary results. To quantify medium and long-term impacts, existing information and data on the hydrological and soil erosion impacts of forest fires at small spatial and temporal scales has been compiled and analyzed. This information is the product of various international and national projects occurring since 1992, consisting of numerous observations on hydrological and erosion processes at the plot and hillslope. Ongoing work is also focusing on collecting data at the micro-catchment scale, and remote sensing imagery is being explored as a complementary information source, especially for large-scale landcover recovery patterns. The ultimate goal is to up-scale this information to meso and regional-scale catchments (100-250 km2) as well as to decade and longer periods. A simple modeling tool is being developed for impact assessment across spatial scales, addressing both on-site effects such as land degradation, and off-site effects such as flood risks and sediment export rates. Preliminary results for a slope-scale application of the model will be presented. The above-mentioned modeling tool, combined with climate change scenarios, will afterwards be used to estimate changes to wildfire regimes (frequency and intensity), and to assess their implications in terms of hydrological and soil erosion processes, and land degradation in general.

Nunes, João. Pedro; Alves Coelho, Celeste; Keizer, Jan Jacob

2010-05-01

290

Climate change and runoff from agricultural catchments in Norway  

Microsoft Academic Search

Purpose – The purpose of this paper is to investigate the effects of extreme weather conditions on runoff, nutrient, and soil loss from agriculture-dominated catchments at different locations in Norway. Design\\/methodology\\/approach – Four catchments have been selected to study the potential effects of climate change on runoff and nutrient loss. The catchments are part of the Agricultural Environmental Monitoring Programme

Johannes Deelstra; Lillian Øygarden; Anne-Grete B. Blankenberg; Hans Olav Eggestad

2011-01-01

291

Conflict, Cooperation, and the New 'Great Game' in the Kura-Araks Basin of the South Caucasus  

Microsoft Academic Search

The Kura-Araks river basin, the largest in the South Caucasus, is an international catchment with five countries - Armenia, Azerbaijan, Georgia, Iran, and Turkey - comprising its watershed. About 65% of the basin area (total = 188,200 km2) falls within the former Soviet republics of Armenia, Azerbaijan, and Georgia, who share many similar circumstances: location in a politically unstable region;

Berrin Basak Vener; Michael E. Campana

292

Contemporary changes in sediment yield in an alpine mountain basin due to afforestation (the upper Drôme in France)  

Microsoft Academic Search

The Baurières plain within the upper Drôme River basin was used to reconstruct recent changes in sediment supply in relation to changes in land use within an alpine catchment. A considerable body of archival information is available. Furthermore, the plain acts as a natural sediment trap and the reach–basin interaction has not been disrupted by human activity. Based on archival

Hervé Piégay; Desmond E. Walling; Norbert Landon; Qinping He; Fred Liébault; Robert Petiot

2004-01-01

293

Modeling anomalous surface - wave propagation across the Southern Caspian basin  

Microsoft Academic Search

The crust of the south Caspian basin consists of 15-25 km of low velocity, highly attenuating sediment overlying high velocity crystalline crust. The Moho depth beneath the basin is about 30 km as compared to about 50 km in the surrounding region. Preliminary modeling of the phase velocity curves shows that this thick sediments of the south Caspian basin are

K. F. Priestly; H. J. Patton; C. A. Schultz

1998-01-01

294

Comparative analysis of base flow recession curves for different Andean catchments  

NASA Astrophysics Data System (ADS)

Little is known in the Paute River basin, Ecuador about the groundwater resources, the relation between aquifers and their recharge zones and interaction with rivers. The pressure from human activities in the river basin is increasing and impacting the surface water quality and quantity, therefore it becomes increasingly useful to estimate the potential of groundwater exploitation as an alternative resource. Due to the lack of specific groundwater data and information, assessment of suitable alternative methods for groundwater research at different scales is considered. In low flow hydrology literature it is noted that the majority of natural gains to streamflow during low-flow periods are derived from releases from groundwater storage, moreover baseflow is generally suggested to be an indicator of groundwater or other delayed sources. Analysis of flow recession curves allows the determination of characteristics of the groundwater reservoir, which is a prerequisite for the separation of baseflow from total discharge and the estimation of groundwater storage and recharge. The flow recession curve at a river cross section is defined as the discharge hydrograph of the basin during a rainless or dry period. Its analysis yields information on the retention characteristics of the basin and of groundwater storage and depletion. In the Paute River basin baseflows are assumed to be originating from Paramo storage, which is largely determined by the high water retention capacity of the soils in combination with their slopes. In the case of the sub-catchment of the Tarqui River, there are evidences based on topography, hydromorphology, discharges and soils that suggest the presence of a major aquifer in the valley. Hence, the goal of this contribution is the comparison and analysis of groundwater conditions based on baseflow recession analysis for the Tarqui and Yanuncay River sub-catchments. Baseflow analyses are translated in recharge and groundwater resources characteristics, as well as relationships with land cover, morphology, geology and rainfall are established and presented. The results are discussed within the framework of increasing pressures on the water system.

Guzman, P.; Batelaan, O.; Wyseure, G.

2012-04-01

295

Coupling a basin erosion and river sediment transport model into a large scale hydrological model: an application in the Amazon basin  

NASA Astrophysics Data System (ADS)

This study presents the first application and preliminary results of the large scale hydrodynamic/hydrological model MGB-IPH with a new module to predict the spatial distribution of the basin erosion and river sediment transport in a daily time step. The MGB-IPH is a large-scale, distributed and process based hydrological model that uses a catchment based discretization and the Hydrological Response Units (HRU) approach. It uses physical based equations to simulate the hydrological processes, such as the Penman Monteith model for evapotranspiration, and uses the Muskingum Cunge approach and a full 1D hydrodynamic model for river routing; including backwater effects and seasonal flooding. The sediment module of the MGB-IPH model is divided into two components: 1) prediction of erosion over the basin and sediment yield to river network; 2) sediment transport along the river channels. Both MGB-IPH and the sediment module use GIS tools to display relevant maps and to extract parameters from SRTM DEM (a 15" resolution was adopted). Using the catchment discretization the sediment module applies the Modified Universal Soil Loss Equation to predict soil loss from each HRU considering three sediment classes defined according to the soil texture: sand, silt and clay. The effects of topography on soil erosion are estimated by a two-dimensional slope length (LS) factor which using the contributing area approach and a local slope steepness (S), both estimated for each DEM pixel using GIS algorithms. The amount of sediment releasing to the catchment river reach in each day is calculated using a linear reservoir. Once the sediment reaches the river they are transported into the river channel using an advection equation for silt and clay and a sediment continuity equation for sand. A sediment balance based on the Yang sediment transport capacity, allowing to compute the amount of erosion and deposition along the rivers, is performed for sand particles as bed load, whilst no erosion or deposition is allowed for silt and clay. The model was first applied on the Madeira River basin, one of the major tributaries of the Amazon River (~1.4*106 km2) accounting for 35% of the suspended sediment amount annually transported for the Amazon river to the ocean. Model results agree with observed data, mainly for monthly and annual time scales. The spatial distribution of soil erosion within the basin showed a large amount of sediment being delivered from the Andean regions of Bolivia and Peru. Spatial distribution of mean annual sediment along the river showed that Madre de Dios, Mamoré and Beni rivers transport the major amount of sediment. Simulated daily suspended solid discharge agree with observed data. The model is able to provide temporaly and spatialy distributed estimates of soil loss source over the basin, locations with tendency for erosion or deposition along the rivers, and to reproduce long term sediment yield at several locations. Despite model results are encouraging, further effort is needed to validate the model considering the scarcity of data at large scale.

Buarque, D. C.; Collischonn, W.; Paiva, R. C. D.

2012-04-01

296

Evaluation of Catchment Storage Volume for Moderating Flow Fluctuations  

NASA Astrophysics Data System (ADS)

Any catchment has a storage volume to some extent as compared with a virtual catchment covered with impervious surface, e.g., glass. Such storage volume (or capacity) contributes to moderate fluctuations of discharge from the catchment. That is, any catchment has a lower peak discharge at flood and higher discharge at drought than the virtual catchment. With respect to comprehensive water management including flood prevention and effective use of water resources, it is important to evaluate the storage capacity in various catchments. In this study, the following two indices calculated by daily rainfall, discharge and evapotranspiration data: water use storage depth (WUSD) and total storage depth (TSD) are used for evaluating the catchment storage capacity. The WUSD is derived as the water storage that is performing for assuring the minimum daily flow. That is, it is the minimum storage capacity when the daily water demand rate is equal to the discharge that gives a stable water supply through the year. Meanwhile, the TSD can be obtained from the changes in storage volume in a catchment. The TDS means the maximum difference of deposited water within one year when the catchment is considered as a vessel. Taking up two forest catchments and one reclaimed farmland catchment in a snow area as case studies, those storage depths are compared. The WUSD and the TSD in the forest catchments within one year are 57-287mm and 166-444mm, respectively, while those in the reclaimed farmland catchment are about 47-159mm and 142-285mm. The results show that the forest catchments are on average more excellent for the function to ensure a stable water supply and regulate floods, although both the WUSD and the TSD in any catchment range widely depending on the climate conditions in each year, and that the amount of snow cover has a significant effect especially on the TSD.

Takimoto, H.; Horino, H.; Tanakamaru, H.

2007-12-01

297

Seasonal variability of suspended sediment transport in the Seine river catchment area (France)  

NASA Astrophysics Data System (ADS)

This study consists in an innovative application of environmental physico-chemical techniques on fluvial sediments with the aim to trace the seasonal changes in suspended sediment transport of the complex Seine river catchment area in northern France. The aim of this project is to develop a detailed understanding for the discrimination of naturally triggered and anthropogenic induced processes and their temporal changes with weather conditions. With a focus on the heavy metal fraction, we determine the regional distribution of the suspended material and search for environmental fingerprints demonstrating the influence of fluvial transport mechanisms, changes in concentration related to discharge variations or different sediment sources, and in-situ alteration caused by variations in the geochemical conditions (oxy-redox, pH, Eh, etc.). To achieve these goals, we apply a combination of straightforward rock magnetic hysteresis measurements (performed using an AGM2900 at the LSCE) and advanced scanning electron microscopy analyses (SEM). This interdisciplinary approach allows refining the detailed analysis of sediment trap samples, originating from Tessier et al. (2003), as recently shown by Franke et al. (2009). In our preliminary results, we observe a general increase in magnetic concentrations from summer to winter conditions, coupled with a magneto-mineralogic change to rather reduced metallic mineral phases. However, each riversection of the Seine system shows its specific trend line depending on the regional initial input, weathering conditions, drainage area and potential pollution sources. A systematic analysis of the detailed results will allow highlighting the climatic/seasonal influence on the metallic particle assembly. Keywords: Seine river system, environmental magnetism, suspended particulate matter, anthropogenic and natural input, magnetic hysteresis, scanning electron microscopy (SEM),, heavy metal pollution, seasonal variability References: Franke, C., Kissel, C., Robin, E., Bonté, P. and Lagroix, F., 2009, Magnetic particle characterization in the Seine river system: Implications for the determination of natural versus anthropogenic input, Geochem. Geophys. Geosyst., doi:10.1029/2009GC002544. Tessier, L., Bonté, P., Mouchel, J.M., Lefevre, I., Sogon, S., Ayrault, S., Le Cloarec, M.F., 2003, Transport et characterisation des matieres en suspension dans le basin de la Seine : Identification des signatures naturelles et anthropiques, 14èmes Journées Scientifiques de l'Environnement : l'Eau, la Ville, la Vie, Créteil : France 2003. http://hal.archives-ouvertes.fr/docs/00/20/30/84/PDF/4-JSE-2003-Manuscrit-Tessier-HAL-2008-01-08.pdf

Franke, Christine; Baati, Selma; Ayrault, Sophie; Bonte, Philippe; Evrard, Olivier; Kissel, Catherine

2010-05-01

298

Comparative assessment of predictions in ungauged basins - Part 1: Runoff-hydrograph studies  

NASA Astrophysics Data System (ADS)

The objective of this assessment is to compare studies predicting runoff hydrographs in ungauged catchments. The aim is to learn from the differences and similarities between catchments in different locations, and to interpret the differences in performance in terms of the underlying climate and landscape controls. The assessment is performed at two levels. The Level 1 assessment is a meta-analysis of 34 studies reported in the literature involving 3874 catchments. The Level 2 assessment consists of a more focused and detailed analysis of individual basins from selected studies from Level 1 in terms of how the leave-one-out cross-validation performance depends on climate and catchment characteristics as well as on the chosen regionalisation method. The results indicate that runoff-hydrograph predictions in ungauged catchments tend to be more accurate in humid than in arid catchments and more accurate in large than in small catchments. The dependence of performance on elevation differs by regions and depends on how aridity varies with elevation and air temperature. The effect of the parameter regionalisation method on model performance differs between studies. However, there is a tendency towards a somewhat lower performance of regressions than other methods in those studies that apply different methods in the same region. In humid catchments spatial proximity and similarity methods perform best while in arid catchments similarity and parameter regression methods perform slightly better. For studies with a large number of catchments (dense stream gauge network) there is a tendency for spatial proximity and geostatistics to perform better than regression or regionalisation based on simple averaging of model parameters from gauged catchments. There was no clear relationship between predictive performance and the number of regionalised model parameters. The implications of the findings are discussed in the context of model building.

Parajka, J.; Viglione, A.; Rogger, M.; Salinas, J. L.; Sivapalan, M.; Blöschl, G.

2013-05-01

299

Comparative assessment of predictions in ungauged basins - Part 2: Flood and low flow studies  

NASA Astrophysics Data System (ADS)

The objective of this paper is to assess the performance of methods that predict low flows and flood runoff in ungauged catchments. The aim is to learn from the similarities and differences between catchments in different places, and to interpret the differences in performance in terms of the underlying climate-landscape controls. The assessment is performed at two levels. The Level 1 assessment is a meta-analysis of 14 low flow prediction studies reported in the literature involving 3112 catchments, and 20 flood prediction studies involving 3023 catchments. The Level 2 assessment consists of a more focused and detailed analysis of individual basins from selected studies from Level 1 in terms of how the leave-one-out cross-validation performance depends on climate and catchment characteristics as well as on the regionalisation method. The results indicate that both flood and low flow predictions in ungauged catchments tend to be less accurate in arid than in humid climates and more accurate in large than in small catchments. There is also a tendency towards a somewhat lower performance of regressions than other methods in those studies that apply different methods in the same region, while geostatistical methods tend to perform better than other methods. Of the various flood regionalisation approaches, index methods show significantly lower performance in arid catchments than regression methods or geostatistical methods. For low flow regionalisation, regional regressions are generally better than global regressions.

Salinas, J. L.; Laaha, G.; Rogger, M.; Parajka, J.; Viglione, A.; Sivapalan, M.; Blöschl, G.

2013-07-01

300

Floods and low flows prediction in ungauged basins - a comparative assessment of studies  

NASA Astrophysics Data System (ADS)

The objective of this study is to assess the performance of methods that predict low flows and flood runoff in ungauged catchments. The aim is to learn from the similarities and differences between catchments in different places, and to interpret the differences in performance in terms of the underlying climate-landscape controls. The assessment is performed at two levels. The Level 1 assessment is a meta-analysis of 14 low flow prediction studies reported in the literature involving 3112 catchments, and 20 flood prediction studies involving 3023 catchments. The Level 2 assessment consists of a more focused and detailed analysis of individual basins from selected studies from Level 1 in terms of how the leave-one-out cross-validation performance depends on climate and catchment characteristics as well as on the regionalisation method. The results indicate that both flood and low flow predictions in ungauged catchments tend to be less accurate in arid than in humid climates and more accurate in large than in small catchments. There is also a tendency towards a somewhat lower performance of regressions than other methods in those studies that apply different methods in the same region, while geostatistical methods tend to perform better than other methods. Of the various flood regionalisation approaches, index methods show significantly lower performances in arid catchments than regression methods or geostatistical methods. For low flow regionalisation, regional regressions are generally better than global regressions.

Salinas, Jose Luis; Laaha, Gregor; Rogger, Magdalena; Parajka, Juraj; Viglione, Alberto; Sivapalan, Murugesu; Bloeschl, Guenter

2013-04-01

301

Bacterial source tracking and shellfish contamination in a coastal catchment.  

PubMed

Introduced pathogens from faecal material can make their way into the aquatic environment from a number of catchment sources. These sources typically include sewage outfalls, seepage from septic tanks, and urban and agricultural runoff. Shellfish as filter feeders are particularly susceptible to contamination in faecally contaminated waters and a range of microbiological indicators have been developed to assess the levels of contamination and likely risks to public health (Hackney and Pierson, 1994). This paper outlines the application of bacterial source tracking (BST) in a shellfish growing area in part of the Port Stephens estuary along the NSW north coast. The approach is based on the premise that bacterial isolates from different faecal sources will have significantly different resistance patterns to the battery of antibiotics and concentrations tested. Faecal streptococci (FS) were isolated from several possible faecal sources: beef and dairy cattle, chickens and humans. The resistance patterns of these isolates to four different concentrations of four antibiotics were compared to those of FS isolates obtained from samples collected upstream and in the vicinity of the oyster leases. Discriminant analysis was performed using the patterns from the known source isolates and the rate of correct classification was determined for each source. The predictive function of discriminant analysis was then used to determine the most probable source of each of the unknown isolates from Tilligerry Creek, the drainage channels to the estuary, and the shellfish leases. Preliminary results are presented here and suggest that there is no single significant source of faecal contamination, rather there are contributions from a range of sources. The findings may have implications for the ways in which land use activities and catchments are managed in similar estuarine locations with a shellfish industry. PMID:12793667

Geary, P M; Davies, C M

2003-01-01

302

Preliminary report on fluid inclusions from halites in the Castile and lower Salado formations of the Delaware Basin, southeastern New Mexico. [Freezing-point depression  

SciTech Connect

A suite of samples composed primarily of halite from the upper Castile and lower Salado Formations of the Permian Basin was selected from Waste Isolation Pilot Plant (WIPP) core for a reconnaissance study of fluid inclusions. Volume percent of these trapped fluids averaged 0.7% to 1%. Freezing-point depressions varied widely and appeared to be unrelated to fluid-inclusion type, to sedimentary facies, or to stratigraphic depth. However, because very low freezing points were usually associated with anhydrite, a relation may exist between freezing-point data and lithology. Dissolved sulfate values were constant through the Castile, then decreased markedly with lesser depth in the lower Salado. This trend correlates very well with observed mineralogy and is consistent with an interpretation of the occurrence of secondary polyhalite as a result of gypsum or anhydrite alteration with simultaneous consumption of dissolved sulfate from the coexisting fluids. Together with the abundance and distribution of fluid inclusions in primary or ''hopper'' crystal structures, this evidence suggests that inclusions seen in these halites did not migrate any significant geographical distance since their formation. 28 refs., 17 figs., 2 tabs.

Stein, C.L.

1985-09-01

303

Phosphorus sources and losses in two arable catchments and implications for catchment management  

NASA Astrophysics Data System (ADS)

Multi-scale catchment experiments allow assessment of the impact of policy measures on nutrient losses from agriculture and water quality and testing of conceptual models of nutrient loss. The potential for catchment-specific responses to be extrapolated to similar catchments country-wide can then help guide future policy measures to achieve water quality targets, such as those in the EU Water Framework Directive (WFD). This paper presents results from the Agricultural Catchments Programme; an integrated advisory/research programme working with stakeholders to assess the efficacy of Ireland's National Action Programme (NAP) of measures in meeting the targets of the Nitrates Directive and WFD. Results are presented for P sources and losses over two water years in two catchments (9.5 and 11.2 km2) with intensive arable agriculture but contrasting soil drainage and geology and resultant hydrologic and nutrient transfer pathways. Phosphorus source pressures were characterised in terms of field-scale soil P status and P balances. Phosphorus loss was characterised in terms of P concentration and loads monitored with high-resolution bank-side analysers. Despite having similar P soil status (18-19 % in excess of agronomic optimum), P losses were much greater from the catchment with more poorly drained soils (0.7 kg ha-1 yr-1) than from the catchment with more freely drained soils (0.2 kg ha-1 yr-1). This paper considers the factors controlling P loss in the two catchments (farm nutrient management, soils, topography and hydrology) to explain the differences between the two catchments and the spatio-temporal variability observed. Agricultural and non-agricultural point sources, in addition to diffuse agricultural sources, are considered. Although both catchments are subject to the same NAP measures, the outcomes, in terms of both P loads and concentrations, showed that inter-annual hydrological patterns and inter-catchment hydrological properties are critical. This highlights the importance of considering soil, geological and landscape factors when considering policy measures to decrease nutrient losses to water and improve the sustainability of agricultural production systems.

Murphy, P. N. C.; Melland, A. R.; Mellander, P.-E.; Shortle, G.; Wall, D.; Jordan, P.

2012-04-01

304

Calibration of hydrological models in glacierized catchments  

NASA Astrophysics Data System (ADS)

Glacierized catchments are important source regions for water, and detailed knowledge of water availability is a prerequisite for good resource management strategies. Reliable and physically consistent runoff simulations become even more important if climate change impacts on alpine water resources are to be assessed. However, hydrological modeling of glacierized catchments is challenging ice melt which represents an additional source of water. Thus, adequate calibration strategies are needed especially in data scarce regions. An important question is how powerful a limited amount of data might be for model calibration. Accordingly, we analyzed the calibration power of limited discharge measurements, mass balance observations and the combination of by means of both Monte Carlo analyzes and multi-criteria model performance evaluation. Ensembles of 100 parameter sets were selected by evaluating the simulations based on a limited and discrete number of discharge measurements, glacier mass balance, and the combination of discharge and mass balance observations. Using these ensembles then the runoff was simulated and evaluated for the entire runoff series. The results for the Vernagtferner catchment and the Venter Ache catchment in Austria indicated that a single annual glacier mass balance observation contained useful information to constrain hydrological models. Combining mass balance observations with a few discharge data improved the internal consistency and significantly reduced the uncertainties compared to parameter set selections based on discharge measurements alone. Information on discharge was required for at least 3 days during the melting season to obtain good ensemble predictions.

Konz, Markus; Seibert, Jan; Braun, Ludwig; Burlando, Paolo

2010-05-01

305

Catchment scale multi-objective flood management  

Microsoft Academic Search

Rural land management is known to affect both the generation and propagation of flooding at the local scale, but there is still a general lack of good evidence that this impact is still significant at the larger catchment scale given the complexity of physical interactions and climatic variability taking place at this level. The National Trust, in partnership with the

Steve Rose; Peter Worrall; Zdenka Rosolova; Gene Hammond

2010-01-01

306

Towards an Objective Model of Catchment Hydrology  

Microsoft Academic Search

The internal structure of catchment hydrologic models remains one of the most subjective elements of coupled hydrologic and biogeochemical models, despite the recognized sensitivity of predictions to the chosen model structure. Hillslope hydrologic studies indicate the high degree of complexity in transport processes at this spatial scale (e.g., variably saturated media, macropore-dominated transport). How can the complexities observed at the

R. P. Hooper; J. J. McDonnell; K. N. Hjerdt; B. L. McGlynn

2001-01-01

307

Integrated catchment assessment of riverine landscape dynamics  

Microsoft Academic Search

The traditional approach to study riverine environments focuses on the river reach scale, with streamflow as a steady state driving force. Here, the accent is on the dynamic nature of streamflow. Impacts of the hydrological regime, of floods and streamflow variability, on riverine landscapes are reviewed. To evaluate such impacts, it is necessary to focus on the entire catchment in

Peter Molnar; Paolo Burlando; Wolfgang Ruf

2002-01-01

308

Hydrologic response of upland catchments to wildfires  

Microsoft Academic Search

To which extent do wildfires affect runoff production, soil erosion and sediment transport in upland catchments? This transient effect is investigated here by combining data of long term precipitation, sediment yield and wildfire records with a fine resolution spatially distributed modeling approach to flow generation and surface erosion. The model accounts for changes in the structure and properties of soil

Maria Cristina Rulli; Renzo Rosso

2007-01-01

309

Deposition, persistence and turnover of pollutants: First results from the EU project AquaTerra for selected river basins and aquifers.  

PubMed

Deposition, turnover and movement of persistent organic pollutants (POP) were investigated in the EU integrated project "AquaTerra", which is among the first funded environmental projects within the 6th Framework Program by the European Commission. Project work integrates across various disciplines that range from biogeochemistry, environmental engineering, computer modelling and chemistry to socio-economic sciences. Field study areas are the river basins of the Ebro, the Meuse, the Elbe and the Danube as well as the 3-km(2) French catchment of the Brévilles Spring. Within the first 2 years of the project more than 1700 samples of atmospherically deposited particles, sediments, and water have been collected in the above-mentioned systems. Results show clear spatial patterns of deposition of polyaromatic hydrocarbons (PAHs) with the highest rates in the Meuse Basin. For local inputs, in the Brévilles sandy aquifer, the contamination of the groundwater by the pesticides atrazine (AT) and deethylatrazine did not decrease even 5 years after their agricultural inputs were stopped. On the other hand, herbicides such as mecroprop (MCPP), and PAHs, were at least partially degraded microbiologically in laboratory studies with soils and aquifer material from selected sites. For sediment transport of contaminants, new flood sampling techniques revealed highest deposition rates of beta-hexachlorocyclohexane (beta-HCH) in river sediments at hotspot areas on the Mulde River in the Bitterfeld region (Elbe Basin, Germany). These selected preliminary results of AquaTerra help to improve fundamental understanding of persistent organic pollutants (POP) in the environment. PMID:17307233

Barth, J A C; Steidle, D; Kuntz, D; Gocht, T; Mouvet, C; von Tümpling, W; Lobe, I; Langenhoff, A; Albrechtsen, H-J; Janniche, G S; Morasch, B; Hunkeler, D; Grathwohl, P

2007-02-20

310

Sediment yield model implementation based on check dam infill stratigraphy in a semiarid Mediterranean catchment  

NASA Astrophysics Data System (ADS)

Soil loss and sediment transport in Mediterranean areas are driven by complex non-linear processes which have been only partially understood. In order to facilitate the comprehension of these phenomena, distributed models can be very helpful tools for sediment yield estimation. In this work, a modelling approach is proposed to reproduce and evaluate erosion and sediment yield processes in a Mediterranean catchment (Rambla del Poyo, Valencia, Spain). Due to the lack of sediment transport records for model calibration and validation, a detailed description of the alluvial stratigraphy infilling a check dam that drains a 12.9 km2 sub-catchment was used as an indirect evidence of sediment yield data. These dam infill sediments showed evidences of at least 15 depositional events (floods) over the time period 1990-2009. The TETIS-SED model, a distributed conceptual hydrological and sediment model, was coupled to the Sediment Trap Efficiency for Small Ponds (STEP) model for reproducing reservoir retention, and it was calibrated and validated using the sedimentation volume estimated for the depositional units associated with discrete runoff events. The results show relatively low net erosion rates compared to other Mediterranean catchments (14 t km-2 yr-1), probably due to the extensive outcrops of limestone bedrock and rather homogeneous vegetation cover, and confirms the ephemeral behaviour of the stream. The modelled sediment production rates offer satisfactory results, further supported by palaeohydrological evidences, showing its great potential for the quantitative analysis of sediment dynamics in ungauged Mediterranean basins.

Bussi, G.; Rodríguez-Lloveras, X.; Francés, F.; Benito, G.; Sánchez-Moya, Y.; Sopeña, A.

2013-03-01

311

A simple framework for relating variations in runoff to variations in climatic conditions and catchment properties  

NASA Astrophysics Data System (ADS)

We use the Budyko framework to calculate catchment-scale evapotranspiration (E) and runoff (Q) as a function of two climatic factors, precipitation (P) and evaporative demand (Eo = 0.75 times the pan evaporation rate), and a third parameter that encodes the catchment properties (n) and modifies how P is partitioned between E and Q. This simple theory accurately predicted the long-term evapotranspiration (E) and runoff (Q) for the Murray-Darling Basin (MDB) in southeast Australia. We extend the theory by developing a simple and novel analytical expression for the effects on E and Q of small perturbations in P, Eo, and n. The theory predicts that a 10% change in P, with all else constant, would result in a 26% change in Q in the MDB. Future climate scenarios (2070-2099) derived using Intergovernmental Panel on Climate Change AR4 climate model output highlight the diversity of projections for P (±30%) with a correspondingly large range in projections for Q (±80%) in the MDB. We conclude with a qualitative description about the impact of changes in catchment properties on water availability and focus on the interaction between vegetation change, increasing atmospheric [CO2], and fire frequency. We conclude that the modern version of the Budyko framework is a useful tool for making simple and transparent estimates of changes in water availability.

Roderick, Michael L.; Farquhar, Graham D.

2011-12-01

312

Numerical investigation of saturated source area behavior at the small catchment scale  

NASA Astrophysics Data System (ADS)

The objective of this research is to explore the relationship between small catchment properties and the temporal growth and decay of saturated source areas (SSA). A simple physics-based hydrologic model, which we call the Sandbox model, is developed for this purpose. A thorough sensitivity analysis is undertaken to evaluate model response to variations in model parameters. Sandbox model output is compared to that from the semi-distributed conceptual model, TOPMODEL, a model with a wide spread acceptance. Plotting the temporal evolution of the extent of saturated source area versus catchment average soil water content during a number of wetting and drying cycles shows a wide variety of trajectories or hysteretic loops. A parametric analysis was performed to quantify the impact of hypothetical catchment properties on the relationship between saturated area extent and basin-average soil water content, revealing hysteretic behavior. It is shown that this hysteresis is the result of changes in groundwater table slope, which is usually less than, and seldom equal to, the land-surface slope in non-saturated areas.

Niedzialek, Justin M.; Ogden, Fred L.

2004-09-01

313

Catchment features controlling nitrogen dynamics in running waters above the tree line (central Italian Alps)  

NASA Astrophysics Data System (ADS)

The study of nitrogen cycling in mountain areas has a long tradition, as it was applied to better understand and describe ecosystem functioning, as well as to quantify long-distance effects of human activities on remote environments. Nonetheless, very few studies, especially in Europe, have considered catchment features controlling nitrogen dynamics above the tree line with focus on running waters. In this study, relationships between some water chemistry descriptors - including nitrogen species and dissolved organic carbon (DOC) - and catchment characteristics were evaluated for a range of sites located above the tree line (1950-2650 m a.s.l.) at Val Masino, in the central Italian Alps. Land cover categories as well as elevation and slope were assessed at each site. Water samples were collected during the 2007 and 2008 snow free periods, with a nearly monthly frequency. In contrast to dissolved organic nitrogen, nitrate concentrations in running waters showed a spatial pattern strictly connected to the fractional extension of tundra and talus in each basin. Exponential models significantly described the relationships between maximum NO3 and the fraction of vegetated soil cover (negative relation) and talus (positive relation), explaining almost 90% of nitrate variation in running waters. Similarly to nitrate but with an opposite behavior, DOC was positively correlated with vegetated soil cover and negatively correlated with talus. Therefore, land cover can be considered one of the most important factors affecting water quality in high-elevation catchments with contrasting effects on N and C pools.

Balestrini, R.; Arese, C.; Freppaz, M.; Buffagni, A.

2013-03-01

314

Catchment features controlling nitrogen dynamics in running waters above the tree line (Central Italian Alps)  

NASA Astrophysics Data System (ADS)

The study of nitrogen cycling in mountain areas has a long tradition, both to better understand and describe ecosystem functioning and to quantify the long-distance effect of human activities on remote environments. Nonetheless, especially in Europe, very few studies paid attention on catchment features controlling nitrogen dynamics above the tree line, with focus on running waters. In this study, relationships between some water chemistry descriptors, including nitrogen species and dissolved organic carbon (DOC), and catchment characteristics were evaluated for a range of sites located above the tree line (1950-2650 m a.s.l.) at Val Masino, in the Central Italian Alps. Land cover categories as well as elevation and slope were assessed at each site. Water samples were collected during the 2007 and 2008 snow free periods, with a nearly monthly frequency. Differently to dissolved organic nitrogen, nitrate concentration in running waters showed a spatial pattern strictly connected to the fractional extension of tundra and talus in each basin. Exponential models significantly described the relationships between maximum NO3-N and the fraction of vegetated soil cover (negative relation) and talus (positive relation), explaining almost 90% of nitrate variation in running waters. Similarly to nitrate, but with an opposite behavior, DOC was positively correlated with vegetated soil cover and negatively correlated with talus. Therefore, land cover can be considered one of the most important factors affecting water quality in high elevation catchments, with a contrasting effect on N and C pools.

Balestrini, R.; Arese, C.; Freppaz, M.; Buffagni, A.

2012-09-01

315

Hydrological functional unit identification - linking observables and concepts towards a minimal adequate catchment representation  

NASA Astrophysics Data System (ADS)

Understanding catchment structures and properties as most probable result of past work during their evolution under the continuous depletion of gradients opens a connection of landscape properties to dominating processes. While a qualitative description from the expert's perspective can comprehend most of these; a distinct objective delineation into functional units, their topology and their connectivity appears far more problematic as a) spatio-temporal scale, b) degrees of freedom and c) aspects of self-organisation have to be brought in accordance. Our study highlights several conceptual approaches aiming to link hydrological landscape understanding, observation and modelling. Moreover, a GIS-based case study for the Attert basin is presented, which shows that from a multitude of possible class combinations, already very few cover the vast majority of the catchment. Consequently, dominating processes, prevailing topologies, most insightful data demands and possible non ad hoc model representations are outlined. The result is a step towards a minimal adequate catchment representation. To base this on physical descriptions with truly observable parameters, we further revise most insightful data for functional unit identification and observation and if and how it can be derived in the landscape and from products available.

Jackisch, C.

2012-04-01

316

A tracer-based assessment of hydrological pathways at different spatial scales in a mesoscale Scottish catchment  

Microsoft Academic Search

Geochemically based hydrograph separation techniques were used in a preliminary assessment to infer how runoff processes change with landscape characteristics and spatial scale (1-233 km2) within a mesoscale catchment in upland Scotland. A two-component end-member mixing analysis (EMMA) used Gran alkalinity as an assumed conservative tracer. Analysis indicated that, at all scales investigated, acidic overland flow and shallow subsurface storm

C. Soulsby; P. Rodgers; R. Smart; J. Dawson; S. Dunn

2003-01-01

317

Geohydrology, water quality, and preliminary simulations of ground-water flow of the alluvial aquifer in the Upper Black Squirrel Creek basin, El Paso County, Colorado  

USGS Publications Warehouse

The upper Black Squirrel Creek basin in eastern El Paso County, Colorado, is underlain by an alluvial aquifer and four bedrock aquifers. Groundwater pumpage from the alluvial aquifer has increased since the mid-1950's, and water level declines have been substantial; the bedrock aquifers virtually are undeveloped. Groundwater pumpage for domestic, stock, agricultural, and municipal uses have exceeded recharge for the past 25 years. The present extent of the effect of pumpage on the alluvial aquifer was evaluated, and a groundwater flow model was used to simulate the future effect of continued pumpage on the aquifer. Measured water level declines from 1974 through 1984 were as much as 30 ft in an area north of Ellicott, Colorado. On the basis of the simulations, water level declines from October 1984 to April 1999 north of Ellicott might be as much as 20 to 30 ft and as much as 1 to 10 ft in most of the aquifer. The groundwater flow models provided a means of evaluating the importance of groundwater evapotranspiration at various stages of aquifer development. Simulated groundwater evapotranspiration was about 43% of the outflow from the aquifer during predevelopment stages but was less than 3% of the outflow from the aquifer during late-development stages. Analyses of 36 groundwater samples collected during 1984 indicated that concentrations of dissolved nitrite plus nitrate as nitrogen generally were large. Samples from 5 of the 36 wells had concentrations of dissolved nitrite plus nitrate as nitrogen that exceeded drinking water standards. Water from the alluvial aquifer generally is of suitable quality for most uses. (USGS)

Buckles, D. R.; Watts, K. R.

1988-01-01

318

Quantitative reconstruction of past soil erosion in the Kirschgraben catchment (Spessart mountains, Central Europe)  

NASA Astrophysics Data System (ADS)

An important problem in Holocene landscape reconstruction is quantifying the relative roles of climatic change and human impact. This project aims to quantify and mass-balance sediment flux in high temporal and spatial resolution, therefore a relatively small gully catchment (Kirschgraben) in the low mountain range Spessart (Germany, Lower Franconia) was chosen as a research area. The catchment is 42 ha in size and total relief is ~200 m. Bedrock is composed of Bunter Sandstone, large areas of which are loess mantled. In the intersection between Kirschgraben fan and the alluvial plain of the Elsava River a moated archaeological site was recently excavated. On the basis of process-based stratigraphy and preliminary chronology, a detailed sequence of landscape changes can be interpreted. Gully incision into Pleistocene sand and gravel sediments during early Holocene resulted in rapid fan development. Non-deposition on the fan surface and minor infilling of the gully system suggests relative catchment stability persisted during prehistoric times, at least until the early iron ages, when human occupation of the fan surface is first recorded. The first evidence of human impact, although minor, is represented by thin colluvial layers on the lower slopes during late Neolithic period. Subsequently, almost the entire catchment has been under agricultural use from the early medieval periods on, and well preserved within field terraces along ancient tenure borders. These features demonstrate widespread and intensive soil loss from the slopes, and eroded material is also preserved in various sediment traps within the catchment. Charcoal production in the catchment probably began at the same time as the widespread soil loss, and lasted until ca. 1900 AD. Anthracological investigations provide the opportunity to reconstruct the vegetation composition on a local scale, and is combined with paleobotanical macro remains and pollen analysis. Initial results indicate a rotating wood - pasture - agriculture cultivation system was used within the catchment on slopes with a north west aspect. The fan area was again occupied in the form of a medieval castle from around 1200 until 1462 AD, coinciding with a rise in the ground water table (due to either dam construction in the trunk stream, a decrease in evapotranspiration, or both) intense gully cut and fill cycles, and high slope instability in the catchment. These erosional processes continue due to the persistence of agricultural and pastural land use and also intense charcoal production until the present day. Initial quantification of the sediment masses in the catchment suggest that most of the eroded material is stored in the gully infills and lower slopes and are not excavated to the fan or the trunk stream. Further work will improve the spatial mass-balance calculations, and in combination with the chronological data, will enable the quantification of a high resolution Holocene sediment flux for the catchment.

Kranz, Annegret; Bork, Hans-Rudolf; Nelle, Oliver; Müller, Ulrich; Fuchs, Markus; Fuelling, Alexander

2010-05-01

319

Creating a Geologic Play Book for Trenton-Black River Appalachian Basin Exploration  

Microsoft Academic Search

Preliminary isopach and facies maps, combined with a literature review, were used to develop a sequence of basin geometry, architecture and facies development during Cambrian and Ordovician time. The main architectural features--basins, sub basins and platforms--were identified and mapped as their positions shifted with time. This is significant because a better understanding of the control of basin geometry and architecture

Douglas G. Patchen; Taury Smith; Ron Riley; Mark Baranoski; David Harris; John Hickman; John Bocan; Michael Hohn

2005-01-01

320

Modelling sediment yield of a highly erodible catchment based on reservoir siltation volumes  

NASA Astrophysics Data System (ADS)

Distributed sediment models are a fundamental tool for the estimation of soil erosion and basins sediment yield. One of the main restrictions for its implementation at the catchment scale is data availability. Sediment yield records are necessary for a correct model calibration and validation. Nevertheless, continuous sediment yield measurements are very scarce, and almost exclusively available for small catchments or experimental plots. This problem can be overcome by using bottom reservoir and lake deposits as estimates of the total sediment yield. In this study, the TETIS model is applied to the Ésera catchment (Central Southern Pyrenees), which flows into the Barasona Reservoir. The TETIS model is a distributed conceptual hydrological model widely used in the last two decades, and it includes a sedimentological extension. Hydrological processes such as soil static storage, infiltration and runoff generation are conceptualized by means of a simple tank structure, while sediment production is estimated by the modified Kilinc-Richardson equation and the sediment channel transport capacity is calculated by means of the Engelund-Hansen formula. The Ésera and its main tributary, the River Isabena, are highly erodible catchments due to presence of badlands stripes on marls located in the middle parts of the basins. Rivers drain into the Barasona Reservoir, a lake that experiences severe siltation. The reservoir has lost most of its original capacity and must be dredged regularly. Five bathymetrical surveys are available, carried out by the Experimental Studies Centre (CEDEX - 1986, 1993, and 1998) and the University of Lleida (2006 and 2007). The depositional history of the Barasona Reservoir has been reconstructed using these measurements and other studies carried out at the reservoir deposits in the last 20 years. This historical reconstruction provides estimated siltation volumes, which have been used for calibrating and validating the sediment submodel. Sediment dry bulk density was incorporated using the Miller formula, and the sediment trap efficiency of the reservoir was calculated by the Brune's formula. Model outcomes were compared to suspended sediment measurements on the River Isábena. Overall, results show a good behaviour of the model, which is able to estimate total deposited volumes into the reservoir and to detect high erosion zones all over the catchment. Nevertheless, some relevant differences with gauged sediments are observed, above all for the period 88-93 (the model error on the total volume is -60%, i.e. the model underestimates the observed sediment accumulation), which are worth a more detailed analysis, e.g. taking into account possible errors in trap efficiency estimation and in reservoir storage capacity estimation.

Bussi, Gianbattista; Francés, Félix; Andrés López-Tarazón, José; Batalla, Ramón J.

2013-04-01

321

Anthropogenic Signatures in Nutrient Loads Exported from Managed Catchments: Emergence of Effective Biogeochemical Stationarity  

NASA Astrophysics Data System (ADS)

Examining the impacts of large-scale human modifications of watersheds (e.g., land-use intensification for food production; hydrologic modification though extensive tile-drainage, etc.) on the hydrologic and biogeochemical responses, and ecological impacts at various scales has been the focus of monitoring and modeling studies over the past two decades. Complex interactions between hydrology and biogeochemistry and the need to predict responses across scales has led to the development of detailed process based models that are computation intensive and calibration dependent. Despite the perceived complexity, our overall hypothesis is that human modifications and intensive management of these watersheds have led to more predictable responses, typical of an engineered, less-complex system rather than natural, complex systems. Thus, simpler and more efficient approaches can be used in these systems for predicting hydrologic and biogeochemical responses. It has been argued that human interferences and climate change may have contributed to the demise of hydrologic stationarity. However, our synthesis of observational data shows that anthropogenic impacts have also resulted in the emergence of effective biogeochemical stationarity in managed catchments. Long-term monitoring data from the Mississippi-Atchafalaya River Basin (MARB) and the Baltic Sea Drainage Basin (BSDB) reveal that inter-annual variations in loads (LT) for total-N (TN) and total-P (TP), and for geogenic constituents exported from a catchment are linearly correlated to discharge (QT), leading to temporal invariance of the flow-weighted concentration, Cf = (LT/QT). Emergence of this consistent pattern across diverse catchments is attributed to the anthropogenic legacy of accumulated nutrient sources generating memory, similar to ubiquitously present sources for geogenic constituents. These responses are characteristic of transport-limited systems. In contrast, in the absence of legacy sources in less-managed catchments, Cf values were highly variable and supply limited. We offer a theoretical explanation for the observed patterns at the event scale, and extend it to consider the stochastic nature of rainfall/flow patterns at annual scales. Our analysis suggests that (1) expected inter-annual variations in nutrient loads can be robustly predicted given discharge variations from hydro-climatic or anthropogenic forcing, and (2) water quality problems in receiving inland and coastal waters would persist until the accumulated storages of nutrients have been substantially depleted. The synthesis bears notable implications on catchment management and on global biogeochemical cycles.

Basu, N. B.; Destouni, G.; Jawitz, J. W.; Thompson, S. E.; Rinaldo, A.; Sivapalan, M.; Rao, P. C.

2010-12-01

322

Spatial variability of herbicide mobilisation and transport at catchment scale: insights from a field experiment  

NASA Astrophysics Data System (ADS)

During rain events, herbicides can be transported from their point of application to surface waters where they may harm aquatic organisms. Since the spatial pattern of mobilisation and transport is heterogeneous, the contributions of different fields to the herbicide load in the stream may differ considerably within one catchment. Therefore, the prediction of contributing areas could help to target mitigation measures efficiently to those locations where they reduce herbicide pollution the most. Such spatial predictions require sufficient insight into the underlying transport processes. To improve the understanding of the process chain of herbicide mobilisation on the field and the subsequent transport through the catchment to the stream, we performed a controlled herbicide application on corn fields in a small agricultural catchment (ca. 1 km2) with intensive crop production in the Swiss Plateau. For two months after application in 2009, water samples were taken at different locations in the catchment (overland flow, tile drains and open channel) with a high temporal resolution during rain events. We also analysed soil samples from the experimental fields and measured discharge, groundwater level, soil moisture and the occurrence of overland flow at several locations. Several rain events with varying intensities and magnitudes occurred during the study period. Overland flow and erosion were frequently observed in the entire catchment. Infiltration excess and saturation excess overland flow were both observed. However, the main herbicide loss event was dominated by infiltration excess. This is in contrast to earlier studies in the Swiss Plateau, demonstrating that saturation excess overland flow was the dominant process. Despite the frequent and wide-spread occurrence of overland flow, most of this water did not directly reach the channel. It mostly got retained in small sinks in the catchment. From there, it reached the stream via macropores and tile drains. Manholes of the drainage system and catch basins for road and farmyard runoff acted as additional shortcuts to the stream. Although fast flow processes like overland and macropore flow reduce the influence of herbicide properties due to short travel times, sorption properties influenced the herbicide transfer from ponding overland flow to tile drains (macropore flow). However, no influence of sorption was observed during the mobilisation of the herbicides from soil to overland flow. These two observations on the role of herbicide properties contradict, to some degrees, previous findings. They demonstrate that valuable insight can be gained by spatially detailed observations along the flow paths.

Doppler, T.; Camenzuli, L.; Hirzel, G.; Krauss, M.; Lück, A.; Stamm, C.

2012-02-01

323

Modeling pesticide transfer during flood events in an agricultural catchment using the SWAT model  

NASA Astrophysics Data System (ADS)

Pesticide monitoring, understanding of pesticide fate and pollution quantification have become major concerns in Europe since the introduction of the Water Framework Directive in 2000. Pesticides can be transported from agricultural catchments to stream networks in either the soluble or particulate phase, depending on their physicochemical properties (solubility, partition coefficient). Quick flood events therefore have a major impact on molecule transport. This study - part of the EU AguaFlash project (http://www.aguaflash-sudoe.eu/) - examined pesticide load dynamics in both the soluble and particulate phases and attempted to quantify their fluxes from various contributing compartments (surface runoff and subsurface and groundwater flows). The hydrological and water quality model SWAT (Soil and Water Assessment Tool, 2005 version) was tested at daily time step to assess the fate and transport of two pesticides with a wide range of solubility (Trifluralin and Metolachlor). SWAT was applied on an 1100 km² agricultural catchment (Save catchment, South-west France). The model was calibrated on discharge, suspended sediment, nitrate and pesticide data collected at the catchment outlet from March 2008 to March 2009, with weekly measurements during base flow and daily during flood events. Agricultural management practices (crop rotation, planting date, fertilizers and pesticide application) were entered into the model in a dominant simplifying land use approach (one rotation by sub-basin, same management operation dates throughout the catchment). Calibration for discharge fluctuations and suspended sediment and nitrate concentration variations was satisfactory. SWAT was able to accurately reproduce observed pesticide concentrations during base flows and peaks during flood events, despite the ‘dominant land use' approximation being used and management practices inputs being averaged for the whole catchment. During the simulation period, simulated preferred pathway for pesticide transport from land area to stream network was surface runoff. In surface runoff, Trifluralin was mainly transferred in the particulate phase, while Metolachlor was mainly transferred in the dissolved phase. Flood events were responsible of most of pesticide transfer. In this case, both the Trifluralin and the Metolachlor were mainly transferred in the dissolved phase. These results are consistent with pesticides loads observed during flood flushes.

Boithias, Laurie; Taghavi, Lobat; Oeurng, Chantha; Polard, Thierry; Ferrant, Sylvain; Jean, Séverine; Probst, Jean-Luc; Merlina, Georges; Sauvage, Sabine; Sánchez-Pérez, José-Miguel

2010-05-01

324

Hydrothermal deposits in the Southern Trough of Guaymas Basin, Gulf of California: Observations and Preliminary Results from the 2003 MBARI Dive Program  

NASA Astrophysics Data System (ADS)

During Leg 2 of the 2003 MBARI expedition to the Gulf of California, the ROV Tiburon completed eight dives to active vent fields in the Southern Trough of Guaymas Basin. Six venting areas were investigated in detail. Tiburon operations included (1) sampling mineral deposits that range from mini-chimneys a few centimeters high to 10-meter-tall sulfide-carbonate structures with wide flanges; (2) collection of 90C to 303C methane, carbon dioxide, and hydrogen-rich vent fluids in gas-tight samplers and plume-laden particulates in Niskin samplers; 3) collection of warm (up to 83C) hydrocarbon-rich sediment push cores; 4) long-term monitoring of three vent sites using thermocouple arrays (see adjacent Tivey et al poster) and osmotically-driven fluid samplers. Seventy days later, the ROV returned to recover the thermocouple arrays and ingrown chimneys. At the lowest temperature sites, fluid (up to 90C) discharged from orifices in sediment surrounded by white to yellow microbial mats. Combined Eh-ISUS (InSitu Ultraviolet Spectrophotometer) sensors mounted on Tiburon identified local increases in bisulfide and decreases in the oxidation/reduction potential (a proxy for methane and hydrogen sulfide) associated with these sites. Massive barite chimneys recovered from the margins of moderate-temperature vent sites are permeated with oil. Chimneys from higher temperature sites, in contrast, lack the liquid hydrocarbon component, and are largely composed of calcium carbonate with lesser anhydrite, amorphous silica, barite, pyrrhotite, Mg-silicate, galena, sphalerite, and chalcopyrite. Mineral precipitation at the southernmost site (Toadstool) is characterized by the formation of carbonate-rich flanges directly above a substrate of altered diatomaceous sediment. The upper sediment crust lies above a stockwork of calcite veins. High-temperature structures at Rebecca's Roost and Broken Mushroom have pagoda-like carbonate-rich flanges trapping pools of hydrothermal fluids that facilitate the growth of centimeter-thick layers of euhedral carbonate and pyrrhotite. Rapidly formed, anhydrite-rich chimneys are present at the summit of the pagoda structures. In-situ laser ablation Sr isotopic analyses of calcite and anhydrite indicate that minerals within flanges precipitate from vent fluids with less than 5% seawater dilution, whereas minerals within the more permeable anhydrite-dominant chimneys precipitate from mixtures of vent fluid with up to 70% seawater.

Stakes, D. S.; Tivey, M. K.; Koski, R. A.; Ortego-Osorio, A.; Preston, C. M.; McCulloch, M. T.; Nakamura, K.; Seewald, J.; Wheat, C. G.

2003-12-01

325

Multicriteria design of rain gauge networks for flash flood prediction in semiarid catchments with complex terrain  

NASA Astrophysics Data System (ADS)

Despite the availability of weather radar data at high spatial (1 km2) and temporal (5-15 min) resolution, ground-based rain gauges continue to be necessary for accurate estimation of storm rainfall input to catchments during flash flood events, especially in mountainous catchments. Given economical considerations, a long-standing problem in catchment hydrology is to establish optimal placement of a small number of rain gauges to acquire data on both rainfall depth and spatiotemporal variability of intensity during extreme storm events. Using weather radar observations and a dense network of 40 tipping bucket rain gauges, this study examines whether it is possible to determine a reliable "best" set of rain gauge locations for the Sabino Canyon catchment near Tucson, Arizona, USA, given its complex topography and dominant storm track pattern. High-quality rainfall data are used to evaluate all possible configurations of a "practical" network having from one to four rain gauges. A multicriteria design strategy is used to guide rain gauge placement, by simultaneously minimizing the residual percent bias and maximizing the coefficient of correlation between the estimated and true mean areal rainfall and minimizing the normalized spatial mean squared error between the estimated and true spatiotemporal rainfall distribution. The performance of the optimized rain gauge network was then compared against randomly designed network ensembles by evaluating the quality of streamflows predicted using the Kinematic Runoff and Erosion (KINEROS2) event-based rainfall-runoff model. Our results indicate that the multicriteria strategy provided a robust design by which a sparse but accurate network of rain gauges could be implemented for semiarid basins such as the one studied.

Volkmann, Till H. M.; Lyon, Steve W.; Gupta, Hoshin V.; Troch, Peter A.

2010-11-01

326

An evaluation of catchment-scale phosphorus mitigation using load apportionment modelling.  

PubMed

Functional relationships between phosphorus (P) discharge and concentration mechanisms were explored using a load apportionment model (LAM) developed for use in a freshwater catchment in Ireland with fourteen years of data (1995-2008). The aim of model conceptualisation was to infer changes in point and diffuse sources from catchment P loading during P mitigation, based upon a dataset comprising geospatial and water quality data from a 256km(2) lake catchment in an intensively farmed drumlin region of the midlands of Ireland. The model was calibrated using river total P (TP), molybdate reactive P (MRP) and runoff data from seven subcatchments. Temporal and spatial heterogeneity of P sources existed within and between subcatchments; these were attributed to differences in agricultural intensity, soil type and anthropogenically-sourced effluent P loading. Catchment rivers were sensitive to flow regime, which can result in eutrophication of rivers during summer and lake enrichment from frequent flood events. For one sewage impacted river, the LAM estimated that point sourced P contributed up to of 90% of annual MRP load delivered during a hydrological year and in this river point P sources dominated flows up to 92% of days. In the other rivers, despite diffuse P forming a majority of the annual P exports, point sources of P dominated flows for up to 64% of a hydrological year. The calibrated model demonstrated that lower P export rates followed specific P mitigation measures. The LAM estimated up to 80% decreases in point MRP load after enhanced P removal at waste water treatments plants in urban subcatchments and the implementation of septic tank and agricultural bye-laws in rural subcatchments. The LAM approach provides a way to assess the long-term effectiveness of further measures to reduce P loadings in EU (International) River Basin Districts and subcatchments. PMID:21429559

Greene, S; Taylor, D; McElarney, Y R; Foy, R H; Jordan, P

2011-03-22

327

Sediment yield model implementation based on check dam infill stratigraphy in a semiarid Mediterranean catchment  

NASA Astrophysics Data System (ADS)

Soil loss and sediment transport in Mediterranean areas are driven by complex non-linear processes which have been only partially understood. Distributed models can be very helpful tools for understanding the catchment-scale phenomena which lead to soil erosion and sediment transport. In this study, a modelling approach is proposed to reproduce and evaluate erosion and sediment yield processes in a Mediterranean catchment (Rambla del Poyo, Valencia, Spain). Due to the lack of sediment transport records for model calibration and validation, a detailed description of the alluvial stratigraphy infilling a check dam that drains a 12.9 km2 sub-catchment was used as indirect information of sediment yield data. These dam infill sediments showed evidences of at least 15 depositional events (floods) over the time period 1990-2009. The TETIS model, a distributed conceptual hydrological and sediment model, was coupled to the Sediment Trap Efficiency for Small Ponds (STEP) model for reproducing reservoir retention, and it was calibrated and validated using the sedimentation volume estimated for the depositional units associated with discrete runoff events. The results show relatively low net erosion rates compared to other Mediterranean catchments (0.136 Mg ha-1 yr-1), probably due to the extensive outcrops of limestone bedrock, thin soils and rather homogeneous vegetation cover. The simulated sediment production and transport rates offer model satisfactory results, further supported by in-site palaeohydrological evidences and spatial validation using additional check dams, showing the great potential of the presented data assimilation methodology for the quantitative analysis of sediment dynamics in ungauged Mediterranean basins.

Bussi, G.; Rodríguez-Lloveras, X.; Francés, F.; Benito, G.; Sánchez-Moya, Y.; Sopeña, A.

2013-08-01

328

Hipsometric analysis and denudation rates in coastal catchments of the Cantabrian Mountains (northern Spain)  

NASA Astrophysics Data System (ADS)

A GIS based analysis including hipsometry and morphometry was performed in four small coastal catchments located in the northern coast of Spain (Porcía, Negro, Esva and Esqueiro). The catchment basins range in area from 56 to 466 km2, and maximum elevations range from 900 to 1200 m. They erode similar substrates made of Paleozoic metamorphic slates, sandstones and quartzites. Digital Terrain Models show values of slope greater that 30° concentrated along the lowest hill slope sections. The catchments cut across a 1.5 M.a. old uplifted wave cut platform, in which the inner edge angle (assumed paleo coast line) is at 100 to 120 m elevations. The Hipsometric integrals show different stages of maturity of the rivers. The largest river (Esva) shows the largest uneroded volume (45%) in contrast to 25% in the other three. In order to obtain an estimation of denudation rates we performed a GIS based analysis to determine the volume of eroded material. A reconstruction of non-eroded topography was made using the Inverse Distance Weighting interpolation method. This interpolation provides the surface that better adjusts the present elevation of the points belonging to the basin boundary. By subtracting the DEM from the reconstructed marker were estimated an eroded total volume and denuded volumes since marine platform uplift (1.5 M.a.). The denudation rates obtained form 1.5 M.a. are 3.3, 3.7, 5.2, and 3.8 cm Kyr-1 for Porcía, Negro, Esva and Esqueiro, respectively. Studies of denudation rates based on in situ cosmogenic nuclides were also performed. Quartz from alluvial bar sediments of the lower part in 3 of the 4 catchments yielded no measurable cosmogenic 21Ne. A lower limit of 3 cm Kyr-1 for basin-average denudation rates could be proposed, assuming that cosmogenic 21Ne is present at the limit of detection (5 x 105 atoms/g). These values are in agreement with the ones calculated in the GIS. In contrast, in the Esquiero River provided a denudation rate of 5 mm Kyr-1.

Fernández Menéndez, Susana; Menendez-Duarte, R.; Stuart, F.; Alvarez-Marrón, J.

2010-05-01

329

Relative impact of topography and soil characteristics on the modelling of hydrological patterns in the Upper Ouémé catchment (North Benin)  

NASA Astrophysics Data System (ADS)

Topography is often a dominant control on hydrological, geomorphological and biological processes within a catchment. Topographic indexes calculated from parameters such as the upslope drained area and the local slope are generally used as measures of hydrological similarity between different locations, thus as indirect measures of the spatial variability of these processes. Soil characteristics such as the hydraulic transmissivity can also be taken into account, as proposed by Beven (1997), but they are commonly neglected because of the general lacking of any information about their spatial pattern. Now, a bias in modelling and predicting hydrological features (notably, the soil water content) can be induced by this approximation, especially where or when the ranges of soil properties vary more significantly than the altitude range, as in the considered catchment: the Upper Ouémé basin (15 000 km², 230-620 m a.s.l.), in Northern Benin. In the framework of the African Monsoon Multidisciplinary Analyses (AMMA) program, a field campaign has been achieved for characterising the hydraulic properties of upper soils and their spatial variability over the whole catchment, according to land use and pedology. Different simulations have been performed, with or without taking into account the transmissivity map, by using TopAMMA, a model based on topographic indexes as TOPMODEL and adapted to the Sudanian region (Le Lay et al., 2008). We will show how the transmissivity pattern impacts the discharge simulations, as well as the simulation of the spatial extent of saturated areas and the changes in catchment wetness over time and space.

Richard, Aloïs; Galle, Sylvie; Peugeot, Christophe; Zin, Isabella

2013-04-01

330

Multi-scale assessment of hydrological behaviour using tracer and GIS techniques in mesoscale catchments in Scotland  

NASA Astrophysics Data System (ADS)

Process conceptualisation is fundamentally important to understanding and predicting the hydrological behaviour of catchments. Here, we present investigations on the spatial and temporal dynamics of hydrometric and tracer data in a large river basin in north east Scotland with seven contrasting subcatchments. We apply an integrated approach using GIS analysis to characterise landscape organisation (land use, topography, geomorphology, and geology) and tracer monitoring to identify runoff sources under different hydrological conditions. This is used as a basis to conceptualise dominant runoff processes at multiple spatial scales. The catchment covers two contrasting geomorphological provinces; (a) a mountainous upland with distinct glacial features and underlying metamorphic bedrock, and (b) the coastal plain with an extensive sandstone aquifer. Isotopes, Gran alkalinity and stream water chemistry are used as environmental tracers to identify major runoff sources and to assess how small scale processes are integrated at the larger spatial scale. Such conceptualization of process understanding is crucial to allow the development of model approaches to predict hydrological response in these catchments. This is obviously important for effective environmental management and provides the basis for improved predictions of climate change impacts on catchment hydrological behaviour.

Capell, R.; Tetzlaff, D.; Soulsby, C.; Hartley, A.

2009-04-01

331

PRELIMINARY PALEOMAGNETIC RESULTS FROM OUTFLOW EOCENE-OLIGOCENE ASH FLOW TUFFS FROM THE WESTERN MARGIN OF THE SAN LUIS BASIN: IMPLICATION FOR THE KINEMATIC EVOLUTION OF THE RIO GRANDE RIFT  

NASA Astrophysics Data System (ADS)

In the Rio Grande rift (RGR), a late Cenozoic continental rift from central Colorado to southern New Mexico, hanging wall margins typically contain en echelon normal fault systems with intervening areas of typically complex structure, called relay zones. Relay zones transfer displacement through complex strain patterns and eventual linkage of faults and hold clues as to how fault zones initiate and grow. The western margin of the RGR at the latitude of the San Luis basin (SLB) exposes laterally continuous Eocene-Oligocene volcanic rocks, well-correlated by 40Ar/39Ar data, and well-preserved rift structures. Ash flow tuffs are usually excellent recorders of the instantaneous geomagnetic field and five ash flow tuffs (ca. 32.3 to 27.3 Ma; including the Saguache Creek, La Jara Canyon, Masonic Park, Fish Canyon, and Carpenter Ridge tuffs) have been sampled in spatial detail along west to east transects of the eastern San Juan volcanic field to the westernmost margin of the RGR at the SLB. Data obtained from our sampling approach will yield a comprehensive definition of relative vertical-axis rotations across the area and will be used to assess the timing of RGR fault linkages. Preliminary paleomagnetic data from the Masonic Park tuff (ca. 28.2 Ma) suggest up to ~17° clockwise rotation between sample locations on the Colorado Plateau and locations to the east, nearest the western margin of the RGR. Preliminary data from the Fish Canyon tuff (ca. 27.8 Ma) show a ~12° clockwise rotation. The relative clockwise vertical-axis rotation of sampling sites in both ash flow tuffs nearest the RGR margin suggests that relay zone development with attending vertical-axis rotation played an important role in the opening of the northern RGR. Our data set is not sufficiently robust at present to test the hypothesis that rotation was taking place concurrently with eruption of these large-volume ash flow tuffs in the early Oligocene, but it is a possibility and if so, the RGR at the latitude of the SLB began to open by about 28 Ma, some 1.5 Ma earlier than previously thought and coeval with late-stage volcanism in the San Juan region.

Mason, S. N.; Geissman, J. W.; Sussman, A. J.

2009-12-01

332

Characterizing hot spots throughout the catchment  

NASA Astrophysics Data System (ADS)

Few catchments in the world are left truly undisturbed. Rather, they are under anthropogenic stress for a variety of reasons ranging from climate forcing to meeting the basic water allocation needs of the population. Reduction in the number of inundation areas has significantly decreased the nutrient and organic matter retention capacity along the river corridor, with major consequences for the both the riverine and coastal ecosystems. Cumulative stress may build up to a "tipping point" which can cause a change or set of changes which could occur non-linearly. In order to mitigate the environmental stress on these ecosystems, management plans are created to balance the needs of the dependent populations and those of ecology. While these catchment-wide plans aim to improve the ecological function of aquatic areas over the large scale, this sledge-hammer approach ignores the inherent heterogeneity in the catchment. Societal (and policy) decisions involve more than abiotic quantification of water storage and flow. A more encompassing ecohydrological view facilitates a more rounded policy framework that has flexibility to accommodate multiple social drivers, and one that can accommodate an "ecosystem improvement" rather than single species improvement. Not every spot in the landscape is equally valuable for specific societal values. Areas of high activity may provide the resilience capacity necessary to prevent catastrophic changes. In times of ecological instability, ecosystem resilience is of paramount importance in maintaining essential ecosystem services. Hot spots of biogeochemical cycling will occur where unique situations arise, such as areas of surface and groundwater interaction, creating spots of localized, high activity. In order to understand the systems' potential to support various habitat niches in the large scale, the identification of specific hot spots or hot moments is necessary. A basal understanding of the concurrent biogeochemical cycles enables the subsequent predictions of the alternative ecosystem responses. This study aims to understand the where and why of hot spots in selected catchments in southeastern Australia and Midwestern United States. The ecosystem response to changes in the catchment will be generated based on various biotic parameters, with the ultimate goal of incorporation into a policy framework at the catchment scale.

Welti, N.; Lockington, D.; Jakeman, T.; Hunt, R.

2012-04-01

333

Inverse distributed hydrological modelling of alpine catchments  

NASA Astrophysics Data System (ADS)

Even in physically based distributed hydrological models, various remaining parameters must be estimated for each sub-catchment. This can involve tremendous effort, especially when the number of sub-catchments is large and the applied hydrological model is computationally expensive. Automatic parameter estimation tools can significantly facilitate the calibration process. Hence, we combined the nonlinear parameter estimation tool PEST with the distributed hydrological model WaSiM. PEST is based on the Gauss-Marquardt-Levenberg method, a gradient-based nonlinear parameter estimation algorithm. WaSiM is a fully distributed hydrological model using physically based algorithms for most of the process descriptions. WaSiM was applied to the alpine/prealpine Ammer River catchment (southern Germany, 710 km2) in a 100×100 m2 horizontal resolution. The catchment is heterogeneous in terms of geology, pedology and land use and shows a complex orography (the difference of elevation is around 1600 m). Using the developed PEST-WaSiM interface, the hydrological model was calibrated by comparing simulated and observed runoff at eight gauges for the hydrologic year 1997 and validated for the hydrologic year 1993. For each sub-catchment four parameters had to be calibrated: the recession constants of direct runoff and interflow, the drainage density, and the hydraulic conductivity of the uppermost aquifer. Additionally, five snowmelt specific parameters were adjusted for the entire catchment. Altogether, 37 parameters had to be calibrated. Additional a priori information (e.g. from flood hydrograph analysis) narrowed the parameter space of the solutions and improved the non-uniqueness of the fitted values. A reasonable quality of fit was achieved. Discrepancies between modelled and observed runoff were also due to the small number of meteorological stations and corresponding interpolation artefacts in the orographically complex terrain. A detailed covariance analysis was performed allowing to derive confidence bounds for all estimated parameters. The correlation between the estimated parameters was in most cases negligible, showing that parameters were estimated independently from each other.

Kunstmann, H.; Krause, J.; Mayr, S.

2005-12-01

334

Inverse distributed hydrological modelling of Alpine catchments  

NASA Astrophysics Data System (ADS)

Even in physically based distributed hydrological models, various remaining parameters must be estimated for each sub-catchment. This can involve tremendous effort, especially when the number of sub-catchments is large and the applied hydrological model is computationally expensive. Automatic parameter estimation tools can significantly facilitate the calibration process. Hence, we combined the nonlinear parameter estimation tool PEST with the distributed hydrological model WaSiM. PEST is based on the Gauss-Marquardt-Levenberg method, a gradient-based nonlinear parameter estimation algorithm. WaSiM is a fully distributed hydrological model using physically based algorithms for most of the process descriptions. WaSiM was applied to the alpine/prealpine Ammer River catchment (southern Germany, 710 km2 in a 100×100 m2 horizontal resolution. The catchment is heterogeneous in terms of geology, pedology and land use and shows a complex orography (the difference of elevation is around 1600 m). Using the developed PEST-WaSiM interface, the hydrological model was calibrated by comparing simulated and observed runoff at eight gauges for the hydrologic year 1997 and validated for the hydrologic year 1993. For each sub-catchment four parameters had to be calibrated: the recession constants of direct runoff and interflow, the drainage density, and the hydraulic conductivity of the uppermost aquifer. Additionally, five snowmelt specific parameters were adjusted for the entire catchment. Altogether, 37 parameters had to be calibrated. Additional a priori information (e.g. from flood hydrograph analysis) narrowed the parameter space of the solutions and improved the non-uniqueness of the fitted values. A reasonable quality of fit was achieved. Discrepancies between modelled and observed runoff were also due to the small number of meteorological stations and corresponding interpolation artefacts in the orographically complex terrain. Application of a 2-dimensional numerical groundwater model partly yielded a slight decrease of overall model performance when compared to a simple conceptual groundwater approach. Increased model complexity therefore did not yield in general increased model performance. A detailed covariance analysis was performed allowing to derive confidence bounds for all estimated parameters. The correlation between the estimated parameters was in most cases negligible, showing that parameters were estimated independently from each other.

Kunstmann, H.; Krause, J.; Mayr, S.

2006-06-01

335

Effect of catchment aspect ratio on geomorphological descriptors  

NASA Astrophysics Data System (ADS)

In recent years several geomorphic measures have been used to test the ability of landscape evolution models to simulate field catchments. These are the hypsometric curve, area-slope relationship, width function and cumulative area distribution. The geomorphic modelling community is only now developing the statistical tools to assess whether these measures are sufficiently discriminatory for use in comparisons between model and field data. To examine this question and the effect of catchment geometry (and especially catchment aspect ratio), a series of synthetic catchments with varying aspect ratio and area matching that of a well understood field catchment were used. This field catchment, for which a set of calibrated hydrology and erosion parameters had been determined, has been used in previous studies to test the ability of the SIBERIA landscape evolution model to simulate field catchments. These synthetic catchments were then allowed to evolve using the calibrated SIBERIA model and the hypsometric curve, areaslope relationship, width function and cumulative area compared with field catchment data. Results show that for a good match to be obtained between simulation and field data using these descriptors as tools of comparison, all that is needed is a catchment with an aspect ratio matching that of the field data (given calibrated erosion parameters). The findings highlight the strengths and weaknesses of the above geomorphic measures when used as a means of comparison between model and field data.

Hancock, Gregory R.

336

A 1000-year history of large floods in the Upper Ganga catchment, central Himalaya, India  

NASA Astrophysics Data System (ADS)

Determining the frequency, magnitude and causes of large floods over long periods in the flood-prone Himalaya is important for estimating the likelihood of future floods. A thousand year record (with some information from 2600 years ago) of the frequency and some estimates of velocities and discharges of large floods has been reconstructed in the Upper Ganga catchment, India, using written reports, litho-stratigraphy and sedimentology, and dated by optical and radiocarbon methods. In the Upper Ganga catchment rainfall triggers large landslides that dam rivers and release large amounts of water when they burst, thereby amplifying the effects of rainfall. The large floods in the catchment may be the result of landslide dam bursts rather than glacial lake bursts, and these are likely to continue and possibly worsen as the monsoon intensifies over the next century. However preliminary information suggests that the recent devastating flood of June 2013 was the result of heavy rainfall not landslide dam bursts. The frequency record is non-random and shows a high frequency between AD 1000 and AD 1300 (omitting uncertainties), then a low frequency until a cluster of floods occurred about 200 years ago, then increased frequency. This temporal pattern is like but not identical with that in Peninsular India, and both appear to be the result of variations in the monsoon.

Wasson, R. J.; Sundriyal, Y. P.; Chaudhary, Shipra; Jaiswal, Manoj K.; Morthekai, P.; Sati, S. P.; Juyal, Navin

2013-10-01

337

Catchment Engineering: A New Paradigm in Water Management  

NASA Astrophysics Data System (ADS)

Recent catchment initiatives have highlighted the need for new holistic approaches to sustainable water management. Here, a catchment engineering approach seeks to describe catchment 'function' (or role) as the principal driver for evaluating how it should be managed in the future. Catchment engineering does not seek to re-establish a natural system but seeks to work with natural processes in order to engineer landscapes so that multiple benefits accrue. This approach involves quantifying and assessing catchment change and impacts but most importantly suggests an urgent and proactive agenda for future planning. In particular, an interventionist approach to managing hydrological flow pathways across scale is proposed. It is already accepted that future management will require a range of scientific expertise and full engagement with stakeholders, namely the general public and policy makers. This inclusive concept under a catchment engineering agenda forces any consortia to commit to actively changing and perturbing the catchment system and thus learn, in situ, how to manage the environment for collective benefits. The shared cost, the design, the implementation, the evaluation and any subsequent modifications should involve all relevant parties in the consortia. This joint ownership of a 'hands on' interventionist agenda to catchment change is at the core of catchment engineering. In this paper we show a range of catchment engineering projects from the UK that have addressed multi-disciplinary approaches to flooding, pollution and ecosystem management whilst maintaining economic food production. Local scale demonstration activities, led by local champions, have proven to be an effective means of encouraging wider uptake. Catchment engineering is a concept that relies on all relevant parties within a catchment to take responsibility for the water quantity and quality that arises from the catchment. Further, any holistic solution requires a bottom up, problem solving agenda which is facilitated by policy makers and is underpinned by scientific knowledge.

Quinn, P. F.; Burke, S.; O'Donnell, G. M.; Wilkinson, M.; Jonczyk, J.; Barber, N.; Nicholson, A.; Proactive Team

2011-12-01

338

Development and evaluation of a new catchment-scale model of floodplain sedimentation  

NASA Astrophysics Data System (ADS)

Fine-sediment storage within floodplain systems typically represents a significant component of the catchment sediment budget and a primary control on sediment-associated nutrient and contaminant fluxes at the basin scale. However, quantitative modeling of floodplain sedimentation within whole catchments represents a significant challenge, not least because hydraulic controls on sediment transport and deposition processes operate at fine spatial scales that cannot be resolved by basin-scale models. This paper outlines a new approach to addressing this problem in order to develop a computationally efficient model of floodplain sedimentation, which retains a strong physical basis. The approach involves two stages. First, a simple theoretical model of overbank sedimentation is presented, which quantifies the relationship between floodplain geometry, overbank discharge, and total sedimentation rate. Second, the precise form that such a relationship should take is established by analysis of the output from high-resolution flow and suspended sediment transport models applied to 22 floodplain reaches along three U.K. rivers. This analysis supports a simple power law model between discharge in excess of bankfull and sedimentation rate per unit valley floor length per unit sediment concentration. The power law model is then incorporated within a sediment budget framework and implemented using a Monte Carlo approach to allow an assessment of uncertainty in the model parameterization. The relative likelihood of competing model structures is determined using estimates of mean annual floodplain sediment storage derived by analysis of the 137Cs content of floodplain sediment cores. Comparison of 137Cs-derived sedimentation rates with uncertainty-bounded model predictions highlights the potential for assessing the significance of overbank sedimentation within catchment sediment budgets using the simple power law model.

Nicholas, A. P.; Walling, D. E.; Sweet, R. J.; Fang, X.

2006-10-01

339

Attributes for NHDPlus Catchments (Version 1.1) for the Conterminous United States: NLCD 2001 Imperviousness  

USGS Publications Warehouse

This data set represents the mean percent impervious surface from the Imperviousness Layer of the National Land Cover Dataset 2001 (LaMotte and Wieczorek, 2010), compiled for every catchment of NHDPlus for the conterminous United States. The source data set represents imperviousness for the conterminous United States for 2001. The Imperviousness Layer of the National Land Cover Data Set for 2001 was produced through a cooperative project conducted by the Multi-Resolution Land Characteristics (MRLC) Consortium. The MRLC Consortium is a partnership of Federal agencies (http://www.mrlc.gov), consisting of the U.S. Geological Survey (USGS), the National Oceanic and Atmospheric Administration (NOAA), the U.S. Environmental Protection Agency (USEPA), the U.S. Department of Agriculture (USDA), the U.S. Forest Service (USFS), the National Park Service (NPS), the U.S. Fish and Wildlife Service (USFWS), the Bureau of Land Management (BLM), and the USDA Natural Resources Conservation Service (NRCS). The NHDPlus Version 1.1 is an integrated suite of application-ready geospatial datasets that incorporates many of the best features of the National Hydrography Dataset (NHD) and the National Elevation Dataset (NED). The NHDPlus includes a stream network (based on the 1:100,00-scale NHD), improved networking, naming, and value-added attributes (VAAs). NHDPlus also includes elevation-derived catchments (drainage areas) produced using a drainage enforcement technique first widely used in New England, and thus referred to as "the New England Method." This technique involves "burning in" the 1:100,000-scale NHD and when available building "walls" using the National Watershed Boundary Dataset (WBD). The resulting modified digital elevation model (HydroDEM) is used to produce hydrologic derivatives that agree with the NHD and WBD. Over the past two years, an interdisciplinary team from the U.S. Geological Survey (USGS), and the U.S. Environmental Protection Agency (USEPA), and contractors, found that this method produces the best quality NHD catchments using an automated process (USEPA, 2007). The NHDPlus dataset is organized by 18 Production Units that cover the conterminous United States. The NHDPlus version 1.1 data are grouped by the U.S. Geologic Survey's Major River Basins (MRBs, Crawford and others, 2006). MRB1, covering the New England and Mid-Atlantic River basins, contains NHDPlus Production Units 1 and 2. MRB2, covering the South Atlantic-Gulf and Tennessee River basins, contains NHDPlus Production Units 3 and 6. MRB3, covering the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy River basins, contains NHDPlus Production Units 4, 5, 7 and 9. MRB4, covering the Missouri River basins, contains NHDPlus Production Units 10-lower and 10-upper. MRB5, covering the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf River basins, contains NHDPlus Production Units 8, 11 and 12. MRB6, covering the Rio Grande, Colorado and Great Basin River basins, contains NHDPlus Production Units 13, 14, 15 and 16. MRB7, covering the Pacific Northwest River basins, contains NHDPlus Production Unit 17. MRB8, covering California River basins, contains NHDPlus Production Unit 18.

Wieczorek, Michael E.; LaMotte, Andrew E.

2010-01-01

340

N Retention in Urbanizing Headwater Catchments  

Microsoft Academic Search

Urbanization can potentially alter watershed nitrogen (N) retention via combined changes in N loading, water runoff, and N\\u000a processing potential. We examined N export and retention for two headwater catchments (?4 km2) of contrasting land use (16% vs. 79% urban) in the Plum Island Ecosystem (PIE-LTER) watershed, MA. The study period included\\u000a a dry year (2001–2002 water year) and a

Wilfred M. Wollheim; Brian A. Pellerin; Charles J. Vörösmarty; Charles S. Hopkinson

2005-01-01

341

Hydrologic and biogeochemical functioning of intensively managed catchments: A synthesis of top-down analyses  

NASA Astrophysics Data System (ADS)

This paper synthesizes a 3-year collaborative effort to characterize the biogeochemical and hydrological features of intensively managed agricultural catchments by combining data analysis, modeling, and preliminary hypothesis testing. The specific focus was on the Midwestern region of the United States. The results suggest that: (1) water management, specifically the homogenization of evapotranspiration losses driven by mono-cultural vegetation cover, and the homogenization of runoff generation driven by artificial drainage, has created engineered, predictable hydrologic systems; (2) nutrient and pesticide management, specifically their regular applications have created two kinds of biogeochemical export regimes: chemostatic (low variability in concentration as exhibited by nitrate) and episodic (high variability in concentration as exhibited by pesticides); (3) coupled mass-balance models for water and solutes reproduce these two regimes as a function of chemical rate constants. Phosphorus transport regimes were found to be episodic at smaller spatial scales, but chemostatic at larger scales. Chemostatic response dominates in transport-limited catchments that have internal sources of the solute to buffer the periodicity in episodic inputs, while episodic response dominates in source-limited catchments. The shift from episodic nitrate export in pristine catchments to chemostatic regimes in managed watersheds was attributed to legacy stores of nitrogen (built from continued fertilizer applications) that buffer interannual variations in biogeochemical processing. Fast degradation kinetics of pesticides prevents the build-up of legacy sources, and leads to episodic export. Analytical expressions were derived for the probability density functions of solute delivery ratio as a function of the stochastics of rainfall-runoff events and biogeochemical controls.

Basu, Nandita B.; Thompson, Sally E.; Rao, P. Suresh C.

2011-10-01

342

Distribution of soil organic carbon in two small agricultural Mediterranean catchments.  

NASA Astrophysics Data System (ADS)

Soil organic carbon (SOC) is a key indicator of soil quality and a major factor for evaluating carbon sequestration schemes in forest and agricultural soils. However, at the farm or catchment scale SOC presents a large spatial variability which complicates the evaluation of soil quality (Gomez et al., 2009) and the certification of the potential for carbon sequestration. We hypothesize that the typical row crop configuration of olive orchards, with cover crops or bare soil in-between the rows, can explain a vast proportion of this variability. However, it is also expected that agricultural activities and topography-driven erosion processes at different scales (Van Oost et al., 2007) will contribute to SOC variability. Given the complexity of this problem and the important experimental effort required to resolve it, there are to our knowledge relatively few studies that have addressed this issue, especially in agricultural soils under Mediterranean conditions. This communications presents a preliminary evaluation of the top 1-m SOC content at two small, 8 and 6.7-ha, catchments in Southern Spain, covered by olive groves, that were intensively sampled in 2011. Spatial variability of SOC is analyzed across tree rows, areas in-between tree rows, and at different depths. The SOC distribution is evaluated against the topography of the catchment and the intensity of the water erosion processes analyzed by a simple model, such as SEDD, as used by Ferro and Porto (2000) and Taguas et al. (2011). The results of this communication will explore and discuss the differences between both catchments, and suggest guidelines for further exploring the sources of SOC variability, while providing guidelines to improve SOC estimation at the field scale for certification purposes.

Gomez, J. A.; Burguet, M.; Taguas, M. E.; Perez, R.; Ayuso, J. L.; Vanwallgehem, T.; Giraldez, J. V.; Vanderlinden, K.

2012-04-01

343

Catchment similarity across hydrological indicators - a data based approach  

NASA Astrophysics Data System (ADS)

We say that a flow duration curve, a flood frequency curve, low flow indices, runoff seasonality, measures of runoff generation and dynamics, among many others are all signatures and can be used to describe catchment similarity. Since they are all signatures of the one catchment, to what extent are they linked? Do we get the same grouping of similar catchments, if we cluster in respect to different signatures or combination of signatures? Does knowledge of one signature provide information on other signatures of the same catchment? How do answers to these questions vary with the hydro-climatic setting? We answer these question using a data based approach based on a data set of about 400 Austrian catchments from 10-130000km² and a set of about 20 signatures describing the variability and dynamics of catchment runoff, runoff generation and the ratio of rainfall and evaporation.

Merz, Ralf; Merz, Bruno

2013-04-01

344

Hydrologic response of upland catchments to wildfires  

NASA Astrophysics Data System (ADS)

To which extent do wildfires affect runoff production, soil erosion and sediment transport in upland catchments? This transient effect is investigated here by combining data of long term precipitation, sediment yield and wildfire records with a fine resolution spatially distributed modeling approach to flow generation and surface erosion. The model accounts for changes in the structure and properties of soil and vegetation cover by combining the tube-flux approach to topographic watershed partition with a parsimonious parametrization of hydrologic processes. This model is used to predict hydrologic and sediment fluxes for nine small catchments in Saint Gabriel mountains of southern California under control (pre-fire) and altered (post-fire) conditions. Simulation runs using a 45 years record of hourly precipitation show the passage of fire to significantly modify catchment response to storms with a major effect on erosion and flood flows. The probability of occurrence of major floods in the post-fire season is shown to increase up to an order of magnitude under same precipitation conditions. Also, the expected anomaly of sediment yield can increase dramatically the desertification hazard in upland wildfire prone areas. One should further consider the role of firefloods produced by the combined occurrence of wildfires and storms as a fundamental source of non-stationarity in the assessment of hydrologic hazard.

Rulli, Maria Cristina; Rosso, Renzo

2007-10-01

345

New boundary conditions for the West Antarctic Ice Sheet: Subglacial topography of the Thwaites and Smith glacier catchments  

NASA Astrophysics Data System (ADS)

Airborne radar sounding over the Thwaites Glacier (TG) catchment and its surroundings provides the first comprehensive view of subglacial topography in this dynamic part of the West Antarctic Ice Sheet (WAIS) and reveals that TG is underlain by a single, broad basin fed by a dendritic pattern of valleys, while Smith Glacier lies within an extremely deep, narrow trench. Subglacial topography in the TG catchment slopes inland from a broad, low-relief coastal sill to the thickest ice of the WAIS and makes deep connections to both Pine Island Glacier and the Ross Sea Embayment enabling dynamic interactions across the WAIS during deglaciation. Simple isostatic rebound modeling shows that most of this landscape would be submarine after deglaciation, aside from an island chain near the present-day Ross-Amundsen ice divide. The lack of topographic confinement along TG's eastern margin implies that it may continue to widen in response to grounding line retreat.

Holt, John W.; Blankenship, Donald D.; Morse, David L.; Young, Duncan A.; Peters, Matthew E.; Kempf, Scott D.; Richter, Thomas G.; Vaughan, David G.; Corr, Hugh F. J.

2006-05-01

346

Hydrological Dynamics In High Mountain Catchment Areas of Central Norway  

NASA Astrophysics Data System (ADS)

Large-scaled landscape structure is regarded as a mosaic of ecotopes where pro- cess dynamics of water and energy fluxes are analysed due to its effects on ecosys- tem functioning. The investigations have been carried out in the continental most Vågå/Oppland high mountains in central Norway since 1994 (LÖFFLER WUN- DRAM 1999, 2000, 2001). Additionally, comparable investigations started in 2000 dealing with the oceanic high mountain landscapes on same latitudes (LÖFFLER et al. 2001). The theoretical and methodological framework of the project is given by the Landscape-Ecological Complex Analysis (MOSIMANN 1984, 1985) and its variations due to technical and principle methodical challenges in this high moun- tain landscape (KÖHLER et al. 1994, LÖFFLER 1998). The aim of the project is to characterize high mountain ecosystem structure, functioning and dynamics within small catchment areas, that are chosen in two different altitudinal belts each in the eastern continental and the western oceanic region of central Norway. In the frame of this research project hydrological and meteorological measurements on ground water, percolation and soil moisture dynamics as well as on evaporation, air humidity and air-, surface- and soil-temperatures have been conducted. On the basis of large-scaled landscape-ecological mappings (LÖFFLER 1997) one basic meteorological station and several major data logger run stations have been installed in representative sites of each two catchment areas in the low and mid alpine belts of the investigation re- gions (JUNG et al. 1997, LÖFFLER WUNDRAM 1997). Moreover, spatial differ- entiations of groundwater level, soil moisture and temperature profiles have been in- vestigated by means of hand held measurements at different times of the day, during different climatic situations and different seasons. Daily and annual air-, surface- and soil-temperature dynamics are demonstrated by means of thermoisopleth-diagrams for different types of ecotopes of the different altitudinal belts. The local differences of temperature dynamics are illustrated in a map as an example of the low alpine al- titudinal belt showing a 4-dimensional characterization (in space and time) of high mountain ecosystem functioning. Hydrological aspects derived from those results are presented showing the large-scaled hydrological dynamics of high mountain catch- ment basins in central Norway. The results of the process analysis of hydrological dynamics in the central Norwegian high mountains are discussed within the frame of 1 investigations on altitudinal changes of mountain ecosystem structure and function- ing (LÖFFLER WUNDRAM [in print]). The poster illustrates the theoretical and methodological conception, methods and techniques, examples from complex data material as well as general outcomes of the project (RÖSSLER [in prep.]. 2

Löffler, J.; Rössler, O.

347

Report card--Murray-Darling Basin--2001.  

PubMed

Ongoing deterioration of the riverine environments of the Murray-Darling Basin led the Murray-Darling Basin Ministerial Council to introduce a Cap in 1995 to halt the growth in diversions of water for consumptive use. This initiative recognised the finite nature of water resources in the Basin and sought to introduce a balance between off-stream use of water and protection of the riverine environment. But the cap is only one step, albeit a fundamental one, in restoring the Basin's rivers--it is a "stake in the ground". Parties to the Murray-Darling Basin Initiative recognise the need to reverse decades of creeping decline if the Basin's rivers and riverine environments are to return to a more ecologically sustainable condition. In the last 12 months, Council and Commission have taken far-reaching decisions designed to restore the Basin's Rivers. Many of these decisions, even 10 years ago, would have been unimaginable. The Report Card will explain the need for a number of recent decisions that will impact on the future of the Basin's rivers. For example, Council's decision to establish an Environmental Manager function in the Office of the Commission was made in the context of the recently agreed Integrated Catchment Management (ICM) Policy, and supporting Sustainable Rivers Audit. The role of targets and accountabilities under the ICM Policy will also be discussed. The Report Card will also present a snapshot of the state of the Basin's rivers and the actions being taken at a range of scales and locations in response to identified problems. Because some of the key initiatives are still in development, this Report Card will set the scene by describing where our attention is being focused and why. PMID:12171345

Goss, K

2002-01-01

348

Groundwater salt accessions to land in the Queensland Murray-Darling Basin, Australia  

NASA Astrophysics Data System (ADS)

Salt accessions from artesian and sub-artesian bores have been calculated for the Queensland Murray-Darling Basin (QMDB), Australia, using available water chemistry, licensing data and a number of assumptions. The majority (~90%) of the salt accessions come from sub-artesian bores used for irrigation (including intensive livestock) purposes. Historically, free-flowing artesian bores in the west of the basin have contributed large quantities of salt, but their contributions have declined with capping and piping of these bores. The highest salt yields (t/km2) are in the Condamine catchment, which also contains 70% of the bores in the region. Groundwater salt accessions are considerably less than atmospheric (rainfall) accessions in all catchments except the Condamine. Further expansion of the coal seam gas industry may substantially increase non-cyclic groundwater accessions, further reducing catchment salt export/import ratios.

Biggs, Andrew J. W.

2011-05-01

349

12 Non-stationarity of basin scale sediment delivery in response to climate change  

Microsoft Academic Search

Results from a cellular river basin evolution model (CAESAR) that contains a detailed multi-grain size sediment-transport model, indicate that over longer time scales (greater than 50 years) the relationship between sediment discharges (Qs) and water discharges (Qw) is not stable when routed through a prototype catchment. By modelling how the daily bedload yield from a medium sized river basin (383km2)

Tom J. Coulthard; John Lewin; Mark G. Macklin

2007-01-01

350

An application of the Kalman filtering technique for Streamflow forecasting in the Upper Murray Basin  

Microsoft Academic Search

In [1], the IHACRES rainfall-runoff model is calibrated for the purpose of predicting streamflow discharge in ten catchments of the Upper Murray Basin using a four-hourly time step. A map and description of the basin can be found in [1,2]. The major aim of the present paper is to describe the subsequent development and testing of a four-hourly time step

A. J. Jakeman

2001-01-01

351

Non-linearity of runoff generation processes in an alpine headwater catchment  

NASA Astrophysics Data System (ADS)

Hydrological systems are often characterized by non-linear behaviours. Particularly, threshold effects due to the complex interactions of many physical controls are frequently observed at the hillslope and catchment scale. The presence of such non-linear behaviours at different scales can reduce our prediction capabilities of hydrological responses. Therefore, investigating the occurrence of hydrological thresholds can help to improve our understanding of the phenomenon and increase our ability to make reliable predictions. In this study we analyzed the runoff response of the small Bridge Creek Catchment (BBC, 0.11 km², North-Eastern Italian Alps). This headwater catchment consists of hillslopes and a distinctive, relatively narrow, riparian zone and is characterized by a fast runoff response. As such, BBC can be considered a representative catchment of the Dolomitic region. Forty rainfall-runoff events occurred between June to mid-October 2005 and 2006 were analyzed. In addition to precipitation and stream discharge measurements, soil moisture at 0-30 cm depth and water table level in 9 piezometers were monitored in two experimental hillslopes located in the lower part of the catchment. In this work we address the following questions: i) what is the dominant control on the threshold in runoff response at BBC? ii) what is the contribution of the hillslopes and riparian zone to the storage and release of water? iii) what controls do soil moisture and precipitation exert on the runoff volume? iv) what influence do soil moisture and precipitation have on the water table variations and the hysteretic relationship between streamflow and groundwater level? Results highlight the strong control exerted by soil moisture on runoff in this catchment: a sharp threshold exists in the relationship between soil water content and runoff coefficient, streamflow, and basin-averaged depth to water table. Low runoff ratios were related to the fast response of the nearly saturated riparian zone. During wetter conditions, when a threshold of soil moisture was exceeded, hillslopes started to contribute to runoff. The riparian contribution to total stormflow was assessed and quantified by comparing the potential runoff from the riparian zone to total storm runoff. A decrease in riparian contribution with increasing antecedent soil moisture underlines the essential role of hillslopes and riparian zones as fundamental landscape units in controlling the catchment hydrological response. A threshold effect was also identified in the relationship between catchment-averaged water table level and antecedent precipitation. Low initial groundwater levels required a slightly larger precipitation depth in order to cause a piezometric response. Finally, a highly non-linear relationship was detected between groundwater level and streamflow at the rainstorm scale. This relation showed a hysteretic behaviour due to the difference in timing of the two responses. The analysis revealed that the extent of the hysteretic loops is dependent on total precipitation and antecedent moisture conditions, with increasing loop size corresponding to higher rainfall and antecedent moisture. These two factors were also related to the total stormflow volume, stressing the importance of soil moisture as a key control in threshold-related runoff generation processes. Key words: threshold behaviour, riparian zone, runoff generation, soil moisture

Penna, Daniele; Tromp van-Meerveld, H. J.; Gobbi, Alberto; Borga, Marco

2010-05-01

352

Rainfall estimation using an optical and a microwave link in the Ardèche catchment.  

NASA Astrophysics Data System (ADS)

The Mediterranean basin is considered to be one of the "hotspots" for climate change. One of the main factors in these changes is the availability and distribution of water, both in time and space. To gain more understanding about the hydrological cycle in the Mediterranean basin and to quantify the related processes, the HYdrological cycle in the Mediterranean EXperiment (HyMeX) was set up. This experiment focuses on inter-annual to decadal variability in the coupled Mediterranean system, running during the second decade of the 21st century. During this long experiment, special intensive observation periods are planned, of which the first passed during the autumn of 2012. Within the HyMeX framework, one working group pays special attention to (flash) floods and heavy rainfall. To investigate this, several (small) catchments were heavily instrumented during the first special observation period. We show the first results on rainfall estimation employing an optical link, a microwave link, and a disdrometer in the Ardèche catch