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1

Runoff simulation in the Ferghana Valley (Central Asia) using conceptual hydrological HBV-light model  

NASA Astrophysics Data System (ADS)

Glaciers and permafrost on the ranges of the Tien Shan mountain system are primary sources of water in the Ferghana Valley. The water artery of the valley is the Syr Darya River that is formed by confluence of the Naryn and Kara Darya rivers, which originate from the mountain glaciers of the Ak-Shyrak and the Ferghana ranges accordingly. The Ferghana Valley is densely populated and main activity of population is agriculture that heavily depends on irrigation especially in such arid region. The runoff reduction is projected in future due to global temperature rise and glacier shrinkage as a consequence. Therefore, it is essential to study climate change impact on water resources in the area both for ecological and economic aspects. The evaluation of comparative contribution of small upper catchments (n=24) with precipitation predominance in discharge and the large Naryn and Karadarya River basins, which are fed by glacial melt water, to the Fergana Valley water balance under current and future climatic conditions is general aim of the study. Appropriate understanding of the hydrological cycle under current climatic conditions is significant for prognosis of water resource availability in the future. Thus, conceptual hydrological HBV-light model was used for analysing of the water balance of the small upper catchments that surround the Ferghana Valley. Three trial catchments (the Kugart River basin, 1010 km²; the Kurshab River basin, 2010 km2; the Akbura River basin, 2260 km²) with relatively good temporal quality data were chosen to setup the model. Due to limitation of daily temperature data the MODAWEC weather generator, which converts monthly temperature data into daily based on correlation with rainfall, was tested and applied for the HBV-light model.

Radchenko, Iuliia; Breuer, Lutz; Forkutsa, Irina; Frede, Hans-Georg

2013-04-01

2

Simulation of the water balance in the Elbe River basin using weather forecast data - A comparison of the hydrological models SWIM and HBV  

NASA Astrophysics Data System (ADS)

The ecohydrological model SWIM (Soil and Water Integrated Model) is applied to the German part of the Elbe River basin since 2012 on a semi-operational basis. In this context, semi-operational means that soil water balance, plant growth and runoff is simulated continuously on different spatial scales, using measured meteorological data of the previous day. In order to extend the prediction range and to include the Czech part of the river basin, we implement weather forecast data from the Global Forecast System (GFS), which is available for the years 2012-2014. At the same time we conduct simulations with the hydrological model HBV using the same input data. The consistency of the data allows a comparison of the results, which fosters the evaluation of the models and helps to improve their deficits. Initially, the calibration of both models is carried out with weather data of the last decade from the German weather service (DWD). Different parameter sets are tested and compared; uncertainties of the simulations can be shown. The validity of the results indicates the strength and weaknesses of each model and therefore determines its predictive capacity. A successful calibration and validation of the models is the basis for simulations with GFS-data of the previous two years and the prospective use of the model system for short (day)- to medium-term (week) predictions of high- and low water, of the soil water balance and of the agricultural plant growth in the Elbe river basin.

Roers, Michael; Vetter, Tobias; Hoffmann, Peter; Wechsung, Frank

2014-05-01

3

Torrential rainfall event in Genoa: Coupled WRF-NMM and HBV model  

NASA Astrophysics Data System (ADS)

On November 4 th, 2011, the city of Genoa was affected by a torrential convective rainfall episode. The finger-shape mesoscale system remained stationary for a significant number of hours on the same area of few square kilometers. About 500 millimeters of rain, one third of the average annual precipitation amount, fell in approximately six hours. A flash flood occurred in the Bisagno river and Fereggiano creek, causing six causalities and the inundation of the Brignole area. For the catchments, where flood events usually occur in a few hours time and peak discharge generally last only a few minutes, it is necessary to use high resolution meteorological data as an input to hydrological model. The effectiveness of flood warning is dependent on the forecast accuracy of certain physical parameters, such as the peak magnitude of the flood, its timing, location and duration. The conceptual HBV rainfall - runoff models enable the estimation of these parameters and provide useful operational forecasts. This paper presents the results of coupled meteorological WRF-NMM and hydrological HBV model. Hourly quantitative precipitation forecasts, for three days ahead, were used as input to the conceptual hydrological model. HBV model was able to predict significant increase of water level with exceedance of regular defence level and exact time of the flood peak on the observed hydrological profile even weather forecast model wasn't successful in the predicition of the hourly amount of precipitation.

Ivkovic, Marija; Dekic, Ljiljana; Mihalovic, Ana

2013-04-01

4

The HBV spatially distributed flash flood forecasting model - The Slovenia case study  

NASA Astrophysics Data System (ADS)

The HBV distributed flash flood forecasting model which is in operational use in northern Austria is applied to a watershed in northwest Slovenia, a case study for the FP6 project HYDRATE. The selected watershed consists of 6 sub-basins with a total area of 646 Km2. Model setup and calibration was performed in this watershed and three long duration rainfall - runoff periods were simulated in order to examine the efficiency of the model. The selected periods included rainfall events that produced high outflows on the exit of the watershed, such as the September 2007 event that caused a flash flooding and severe damages to the towns of Zali Log and Zelezniki. The model uses 1km grid rainfall and temperature data of fifteen minute time intervals in order to simulate the rainfall - runoff process. Inverse distance weighting interpolation is used in order to generate the spatially distributed rainfall and temperature while the hydrological parameters are defined for each 1km grid cell that correspond to one hydrological response units (HRU - areas with analogous hydrogeological characteristics). The basic calibration of the HBV model is based on hydrological parameters of each HRU, parameters that control the rainfall - runoff process within the basin and non HRU parameters that control the river routing between the basins. The model performance is based on seven efficiency criteria that were selected as appropriate for long simulation periods, e.g. coefficient of determination R2 and Nash Sutcliffe efficiency E. The HBV model produced satisfactory results for the three rainfall periods and could be used as an operational model in Slovenia as well.

Tsanis, I. K.; Grillakis, M. G.; Blöschl, G.; Poga?nik, N.

2009-04-01

5

Immunosuppressive Drugs Modulate the Replication of Hepatitis B Virus (HBV) in a Hydrodynamic Injection Mouse Model  

PubMed Central

Hepatitis B virus (HBV) reactivation and recurrence are common in patients under immunosuppression and can be controlled by hepatitis B immunoglobulin, antivirals, and hepatitis B vaccine. However, the detailed analysis of HBV infection under immunosuppression is essential for the prophylaxis and therapy for HBV reactivation and recurrence. In this study, HBV replication and T cell responses were analyzed in a HBV-transfected mouse model under immunosuppressive therapy. During the treatment, HBV replication was at a high level in mice treated with dexamethasone, cyclosporine, and cyclophosphamide, whereas was terminated in mice treated with mycophenolate mofetil. After the withdrawal, HBV replication was at low or high levels in the dexamethasone-treated mice or in both cyclosporine- and cyclophosphamide-treated mice. The early withdrawal of cyclosporine allowed the recovery of suppressed T cell responses and led to subsequent HBV clearance, while the adoptive immune transfer to the mice with HBV persistence led to HBV suppression. Taken together, long-term HBV persistence under immunosuppression depends on the immunosuppressive drugs used and on the treatment duration and is mediated by the suppressed intrahepatic CD8 T cell response. These data may be helpful for individualized immunosuppressive therapy in patients with high risk of HBV reactivation and recurrence, and the mouse system is suitable for studying HBV reactivation and recurrence under immunosuppression. PMID:24465734

Huang, Shunmei; Song, Zhitao; Wu, Jun; Zhang, Ejuan; Zhu, Zhenni; Zhu, Bin; Yin, Ying; Lin, Yong; Xu, Yang; Zheng, Xin; Lu, Mengji; Yang, Dongliang

2014-01-01

6

Modeling the adaptive immune response in HBV infection  

Microsoft Academic Search

The aim of this work is to investigate a new mathematical model that describes the interactions between Hepatitis B virus\\u000a (HBV), liver cells (hepatocytes), and the adaptive immune response. The qualitative analysis of this as cytotoxic T lymphocytes\\u000a (CTL) cells and the antibodies. These outcomes are (1) a disease free steady state, which its local stability is characterized\\u000a as usual

Noura Yousfi; Khalid Hattaf; Abdessamad Tridane

7

A Stochastic Model and Monte-Carlo Simulation of HBV  

Microsoft Academic Search

The world health organization has estimated that around 300 million persons world wide suer from chronic hepatitis B virus (HBV) infection 25-30 % of whom eventually will die from chronic sequel (4). Interest in HBV epidemiology has increased due to the HIV (AIDS) epidemic. Transmission routs and clinical features show many similarities for these infections, and better understanding of HBV

I. A. Moneim; G. A. Mosa

8

Estimation of instantaneous peak flow from simulated maximum daily flow using the HBV model  

NASA Astrophysics Data System (ADS)

Instantaneous peak flow (IPF) data are the foundation of the design of hydraulic structures and flood frequency analysis. However, the long discharge records published by hydrological agencies contain usually only average daily flows which are of little value for design in small catchments. In former research, statistical analysis using observed peak and daily flow data was carried out to explore the link between instantaneous peak flow (IPF) and maximum daily flow (MDF) where the multiple regression model is proved to have the best performance. The objective of this study is to further investigate the acceptability of the multiple regression model for post-processing simulated daily flows from hydrological modeling. The model based flood frequency analysis allows to consider change in the condition of the catchments and in climate for design. Here, the HBV model is calibrated on peak flow distributions and flow duration curves using two approaches. In a two -step approach the simulated MDF are corrected with a priory established regressions. In a one-step procedure the regression coefficients are calibrated together with the parameters of the model. For the analysis data from 18 mesoscale catchments in the Aller-Leine river basin in Northern Germany are used. The results show that: (1) the multiple regression model is capable to predict the peak flows with the simulated MDF data; (2) the calibrated hydrological model reproduces well the magnitude and frequency distribution of peak flows; (3) the one-step procedure outperforms the two-step procedure regarding the estimation of peak flows.

Ding, Jie; Haberlandt, Uwe

2014-05-01

9

netherland hydrological modeling instrument  

NASA Astrophysics Data System (ADS)

Netherlands Hydrological Modeling Instrument A decision support system for water basin management. J.C. Hoogewoud , W.J. de Lange ,A. Veldhuizen , G. Prinsen , The Netherlands Hydrological modeling Instrument (NHI) is the center point of a framework of models, to coherently model the hydrological system and the multitude of functions it supports. Dutch hydrological institutes Deltares, Alterra, Netherlands Environmental Assessment Agency, RWS Waterdienst, STOWA and Vewin are cooperating in enhancing the NHI for adequate decision support. The instrument is used by three different ministries involved in national water policy matters, for instance the WFD, drought management, manure policy and climate change issues. The basis of the modeling instrument is a state-of-the-art on-line coupling of the groundwater system (MODFLOW), the unsaturated zone (metaSWAP) and the surface water system (MOZART-DM). It brings together hydro(geo)logical processes from the column to the basin scale, ranging from 250x250m plots to the river Rhine and includes salt water flow. The NHI is validated with an eight year run (1998-2006) with dry and wet periods. For this run different parts of the hydrology have been compared with measurements. For instance, water demands in dry periods (e.g. for irrigation), discharges at outlets, groundwater levels and evaporation. A validation alone is not enough to get support from stakeholders. Involvement from stakeholders in the modeling process is needed. There fore to gain sufficient support and trust in the instrument on different (policy) levels a couple of actions have been taken: 1. a transparent evaluation of modeling-results has been set up 2. an extensive program is running to cooperate with regional waterboards and suppliers of drinking water in improving the NHI 3. sharing (hydrological) data via newly setup Modeling Database for local and national models 4. Enhancing the NHI with "local" information. The NHI is and has been used for many decision supports and evaluations. The main focus of the instrument is operational drought management and evaluating adaptive measures for different climate scenario's. It has also been used though as a basis to evaluate water quality of WFD-water bodies and measures, nutrient-leaching and describing WFD groundwater bodies. There is a toolkit to translate the hydrological NHI results to values for different water users. For instance with the NHI results agricultural yields can be calculated, effects on ground water dependant ecosystems, subsidence, shipping, drinking water supply. This makes NHI a valuable decision support system in Dutch water management.

Hoogewoud, J. C.; de Lange, W. J.; Veldhuizen, A.; Prinsen, G.

2012-04-01

10

A comparison of SRM and HBV models for real time runoff forecasting in the Upper Euphrates Basin, Turkey  

NASA Astrophysics Data System (ADS)

Predicting snowmelt runoff in the mountainous eastern part of Turkey at a daily time step is important in water resource management as it constitutes nearly 2/3 in volume of the total yearly runoff during spring and early summer months. Keeping track of snow dynamics as well as forecasting the amount and timing of snowmelt runoff in the headwaters of the trans-boundary Euphrates River, where large dams are located, is a crucial and challenging task concerning the practical importance and great demand for real time forecasting of melt water. In mountainous regions, data limitations prevent detailed understanding of the variability of snow cover and melt. In situ snowpack measurements are sparsely distributed relative to snowpack heterogeneity therefore, to supplement ground measurement networks, remotely sensed images of snow covered area (SCA) provide useful information for runoff prediction during the snowmelt season. SCA has been used as a direct input to hydrological models such as Snowmelt Runoff Model (SRM) or as a means of assimilating hydrologic model snowpack and checking the internal validity as in the case of HBV model. Alternative ways of handling melt water modeling using satellite derived SCA is discussed, with emphasis on the contrasting treatments in two widely used hydrologic models, SRM and HBV. The greatest similarity between the two models is that each uses a temperature index method to predict melt rate whereas the greatest difference lies in the way snow cover is handled. Moderate Resolution Imaging Spectroradiometer (MODIS) daily snow cover products with 500 m spatial resolution are used to derive SCA data in this study. Since the cloud obscuring problem degrades the use of satellites with optical sensors, a special combination and filtering methodology is utilized to reduce cloud coverage of the product. Both models are used to simulate runoff for the years 2001-2010 with model efficiency above 0.86 and volume difference less than 2.5%. Finally, operational snowmelt runoff forecasting is carried out for 2011 ablation season using numerical weather prediction (Mesoscale Model 5) data as forcing input variables. Discussion of results are supervised to reflect the general debates in hydrologic modeling in terms of parameters and calibration, internal validation, the value and limitations of using satellite derived and numerical weather prediction data. Key words: snow, SRM, HBV, forecasting, Upper Euphrates Basin

Sorman, A. A.; Sensoy, A.; Yamankurt, E.; Gozel, E.

2012-04-01

11

PATHS groundwater hydrologic model  

SciTech Connect

A preliminary evaluation capability for two-dimensional groundwater pollution problems was developed as part of the Transport Modeling Task for the Waste Isolation Safety Assessment Program (WISAP). Our approach was to use the data limitations as a guide in setting the level of modeling detail. PATHS Groundwater Hydrologic Model is the first level (simplest) idealized hybrid analytical/numerical model for two-dimensional, saturated groundwater flow and single component transport; homogeneous geology. This document consists of the description of the PATHS groundwater hydrologic model. The preliminary evaluation capability prepared for WISAP, including the enhancements that were made because of the authors' experience using the earlier capability is described. Appendixes A through D supplement the report as follows: complete derivations of the background equations are provided in Appendix A. Appendix B is a comprehensive set of instructions for users of PATHS. It is written for users who have little or no experience with computers. Appendix C is for the programmer. It contains information on how input parameters are passed between programs in the system. It also contains program listings and test case listing. Appendix D is a definition of terms.

Nelson, R.W.; Schur, J.A.

1980-04-01

12

Mathematical Modeling of Watershed Hydrology  

Microsoft Academic Search

Mathematical modeling of watershed hydrology is employed to address a wide spectrum of environmental and water re- sources problems. A historical perspective of hydrologic modeling is provided, and new developments and challenges in watershed models are discussed. These include data acquisition by remote sensing and space technology, digital terrain and elevation models, chemical tracers, geographic information and data management systems,

Vijay P. Singh

2002-01-01

13

Complexity regularized hydrological model selection  

NASA Astrophysics Data System (ADS)

Ill-posed hydrological model selection problems (that may be unstable or have non-unique solutions) are regularized with hydrological model complexity as the stabilizer. We propose and apply a notion of model complexity, based on Vapnik-Chervonenkis generalization theory, to complexity regularized hydrologic model selection. Better hydrologic models (better performance on future unseen data) on small sample sizes are identified using complexity regularized model selection than when using traditional model selection (without regularization) while both converge in performance for large samples (i.e. regularized model selection is 'consistent'). Case studies using SAC-SMA, SIXPAR and flexible model structures are used to 1) compute and compare model complexities of different model structures, 2) demonstrate the 'consistency' of complexity regularized model selection and 3) demonstrate that regularized model selection identifies the best model structure (out of a set of competing structures) on small sample sizes better than un-regularized model selection.

Arkesteijn, Liselot; Pande, Saket; Savenije, Hubert

2014-05-01

14

A comparison of SRM and HBV models for real time runoff forecasting in the Upper Euphrates Basin, Turkey  

NASA Astrophysics Data System (ADS)

Predicting snowmelt runoff in the mountainous eastern part of Turkey at a daily timescale is important in water resource management as it constitutes nearly 2/3 in volume of the total yearly runoff during spring and early summer months. Keeping track of snow dynamics and forecasting the amount and the timing of snowmelt runoff in the headwaters of the trans-boundary Euphrates River, where large dams are located, is a crucial and challenging task concerning the practical importance and great demand for real time forecasting of meltwater. In mountainous regions, data limitations prevent detailed understanding of the variability of snow cover and melt. In situ snowpack measurements are sparsely distributed relative to snowpack heterogeneity therefore to supplement ground measurement networks, remotely derived images of snow covered area (SCA) provides useful information for runoff prediction during the snowmelt season. SCA has been used as a direct input to hydrological models such as Snowmelt Runoff Model (SRM) or as a means of updating hydrologic model snowpack simulations and checking the internal validity of snowmelt runoff model as in the case of HBV model. Alternative ways of handling meltwater modeling using satellite derived SCA is discussed, with emphasis on the contrasting treatments in two widely used models, HBV and SRM. The greatest similarity between two models is that each uses a temperature index method to predict melt rate and the greatest difference between the models is in the way snow cover is handled. Moderate Resolution Imaging Spectroradiometer (MODIS) daily snow cover products with 500 m spatial resolution are used to derive SCA data in this study. Since the cloud obscuring problem degrades the use of satellites with optical sensors, a special combination and filtering methodology is used to reduce cloud coverage of the product. Both models are used to simulate runoff for the years 2003-2010 with model efficiency above 0.85 and volume difference around 2.5% and model parameters are calibrated in these applications. Finally, an operational snowmelt runoff forecasting is carried out for 2011 ablation season using numerical weather prediction Mesoscale Model 5 (MM5) data as forcing input variables. Discussion of results are supervised to reflect the general debates in hydrological modeling in terms of parameters and calibration, internal validation, the value and limitations of using satellite derived data.

Sorman, A.; Sensoy, A.; Gozel, E.; Yamankurt, E.; Sorman, U.

2011-12-01

15

Pollution control and hydrologic Modeling  

NSDL National Science Digital Library

Eugenio Y. Arima, Hobart and William Smith Colleges Summary This assignment will introduce students to surface hydrologic modeling in GIS and derived products such as stream power and wetness indices. Context Type ...

Arima, Eugenio

16

Modeling the effects of covalently closed circular DNA and dendritic cells in chronic HBV infection.  

PubMed

The contribution of covalently closed circular DNA (cccDNA) and dendritic cells (DCs) to the progression of chronic hepatitis B virus (HBV) infection remains largely unknown. A dynamic model with seven cell types was proposed based on the biological mechanisms of viral replication and the host immune response. The cccDNA self-amplification rate was found to be closely related to both the basic reproduction number of the virus and the immune response. The combination of the cccDNA self-amplification rate and the initial activated DC count induces rich dynamics. Applying our model to the clinical data of untreated patients, we found that chronic patients have a high cccDNA self-amplification rate. For antiviral treatment, an overall drug effectiveness was introduced and the critical drug effectiveness was obtained. The model predicts that timely long-term therapy is needed to reduce the symptoms of HBV and to maintain the benefits of treatment. PMID:24816182

Li, Qiang; Lu, Furong; Deng, Guohong; Wang, Kaifa

2014-09-21

17

The influence of HBV model calibration on flood predictions for future climate  

NASA Astrophysics Data System (ADS)

The temporal variability of HBV rainfall-runoff model parameters was tested to address the influence of climate characteristics on the values of model optimal parameters. HBV is a conceptual model with a physically-based structure that takes into account soil moisture, snow-melt and dynamic runoff components. The model parameters were optimized by the DEGL method (Differential Evolution with Global and Local neighbours) for a set of catchments located in Poland. The methodology consisted of the calibration and cross-validation of the HBV models on a series of five-year periods within a moving window. The optimal parameter values show large temporal variability and dependence on climatic conditions described by the mean and standard deviation of precipitation, air temperature and PET. Derived regressions models between parameters and climatic indices were statistically significant at the 0.05 level. The set of model optimal values was applied to simulate future flows in a changed climate. We used the precipitation and temperature series from 6 RCM/GCM models for 2071-2100 following the A1B climate change scenario. The climatic variables were obtained from the KLIMADA project. The resulting flow series for the future climate scenario were used to derive flow indices, including the flood quantiles. Results indicate a large influence of climatic variability on flow indices. This work was partly supported by the project "Stochastic flood forecasting system (The River Vistula reach from Zawichost to Warsaw)" carried out by the Institute of Geophysics, Polish Academy of Sciences by order of the National Science Centre (contract No. 2011/01/B/ST10/06866). The rainfall and flow data were provided by the Institute of Meteorology and Water Management (IMGW), Poland.

Osuch, Marzena; Romanowicz, Renata

2014-05-01

18

Weather Radar and Hydrology 1 Influence of rainfall spatial variability on hydrological modelling: a  

E-print Network

Weather Radar and Hydrology 1 Influence of rainfall spatial variability on hydrological modelling variability as well as characteristics and hydrological behavior of catchments, we have proceeded simulator and a distributed hydrological model (with four production functions and a distributed transfer

Paris-Sud XI, Université de

19

On the predictability of hydrological droughts with a conceptual model  

NASA Astrophysics Data System (ADS)

Since the extreme summer of 2003 the importance of early drought warning is increasingly recognized also in apparently water-rich countries like Switzerland. The year 2011 provided additional examples of drought conditions in Switzerland, which are expected to become more frequent in the future. So far, little has been done regarding drought forecasting in Europe. A fundamental question related to drought forecasting is: How long before a hydrological drought actually occurs, can it be predicted? To address this question, we assessed the relative importance of current hydrological state and weather during the prediction period. A conceptual catchment model, the HBV model, was calibrated to 21 Swiss catchments and for each of them two modeling experiments were performed: 1) Streamflow was simulated starting with the same initial hydrological state but with different observed series (i.e., from different years) of precipitation and temperature to derive 'predictions'. 2) Streamflow was simulated using various initial hydrological states, but the same longterm means of precipitation and temperature as forcing. Both experiments were repeated four times, shifting the start of the simulations to different seasons. The relative importance of initial hydrological state and weather during the prediction period was evaluated by estimating the persistence of the initial hydrological states in the prediction for both experiments. To further distinguish between effects of weather and catchment properties, the resulting persistences were tested on their sensitivity to changes in total precipitation amounts and air temperature. For the investigated catchments the persistence in streamflow appeared to be more depending on catchment characteristics and less on the start of the prediction period. Drier initial conditions of soil moisture and deeper groundwater storage resulted for most catchments in longer persistence estimates, while the initial conditions of snow and upper groundwater storage showed no clear effect on the persistence. From the preliminary results of the sensitivity analysis, the persistence estimates seem not sensitive to changes in precipitation.

Staudinger, Maria; Seibert, Jan

2013-04-01

20

Exploring the effect of spatial disaggregation of conceptual hydrologic models for improved flow forecasting  

NASA Astrophysics Data System (ADS)

The availability of gridded climatic data, high resolution Digital Elevation Maps (DEM), soil, land-use and land-cover data has motivated researchers to exploit these data for more accurate distributed hydrologic modeling. However, with increased disaggregation there is the introduction of numerous parameters and conceptualized processes that are unobservable. In this study we explore the advantage of employing spatially distributed climatic and geographic information in the context of a disaggregated conceptual hydrologic modeling framework by developing distributed model versions for three hydrologic models: HYMOD (Hydrologic Model), HBV (Hydrologiska Byrans Vattenbalansavdelning), and SAC-SMA (Sacramento Soil Moisture Accounting). This study proposes a general framework for building a distributed conceptual hydrological model by coupling a rainfall-runoff model to a routing model which is based on the formularized sub-basin unit hydrograph and the linearized Saint-Venant equation. To deal with a very large number of model parameters resulting from the distributed system modeling approach, hydrological similarity and landscape classification derived from the geospatial database is used to reduce the complexity in the process of model parameter estimation. Tests for the Iowa River basin show that three distributed models outperform lumped model versions in terms of reproducing observed streamflow for both calibration and validation periods. Model calibration strategies informed by geospatial information yield flow predictions comparable to the fully distributed model simulations. Results from this study are encouraging and indicate that the proposed framework holds promise for making improved predictions of hydrologic system response.

Wi, S.; Brown, C. M.

2013-12-01

21

Model Discrepancy in the Saturated Path Hydrology Model: Initial Analysis  

E-print Network

Model Discrepancy in the Saturated Path Hydrology Model: Initial Analysis Tom Fricker University discrepancy in the Saturated Path Hydrology Model (logSPM, Kuczera et al., 2006). The purpose). 1 #12;3 The Saturated Path Hydrology Model We consider the Saturated Path Hydrology Model (log

Oakley, Jeremy

22

Hydrological model parameter uncertainty in investigations of climate change impacts on peak flow across Europe  

NASA Astrophysics Data System (ADS)

Mulit-model ensemble approaches are usually used to investigate the hydrological impacts of climate change and their associated uncertainties. Uncertainties introduced by differing GCM/RCM combinations are assumed to have the largest influence on the overall uncertainty whereas the uncertainty derived from the hydrological model parameterisation is often assumed to have only a minor influence within the entire model chain. However, this does not always need to be the case, especially when changes in flood seasonality are likely. Since hydrological model calibration is a well-established tool for hydrologists, this comprises a possible field for improvements within climate impact studies. In this study we investigate the effect of using four different objective functions for the calibration of the HBV hydrological model in seven catchments across Europe, which represent differing geographical and climatological conditions. The objective functions used here are either modifications or extensions of the Nash-Sutcliffe criterion (NSE). Two of the objective functions are especially tailored to fit the model with respect to peak flows, while the other two are designed to estimate an optimal NSE whilst also minimising the volumetric bias. The global Dynamically Dimensioned Search (DDS) algorithm and a subsequent Monte-Carlo simulation was used to calibrate the HBV models for all seven catchments and to detect 4x25 best-fit parameter sets. These parameter sets are then applied to model the observed and future climate with respect to peak flows in all seven catchments. The aims of this study are (1) to address the parameter uncertainties associated by the 4x25 best-fit parameter sets and (2) to identify the objective functions that are best suited for calibrating the HBV model with respect to investigating changes in the frequency and intensity of flooding.

Vormoor, Klaus; Lawrence, Deborah; Engin, Batuhan; Martinkova, Marta; Osuch, Marzena; Willems, Patrick; Yücel, Ismail

2014-05-01

23

Integration of Local Hydrology into Regional Hydrologic Simulation Model  

NASA Astrophysics Data System (ADS)

South Florida hydrology is dominated by the Central and South Florida (C&SF) Project that is managed to provide flood protection, water supply and environmental protection. A complex network of levees canals and structures provide these services to the individual drainage basins. The landscape varies widely across the C&SF system, with corresponding differences in the way water is managed within each basin. Agricultural areas are managed for optimal crop production. Urban areas maximize flood protection while maintaining minimum water levels to protect adjacent wetlands and local water supplies. "Natural" areas flood and dry out in response to the temporal distribution of rainfall. The evaluation of planning, regulation and operational issues require access to a simulation model that captures the effects of both regional and local hydrology. The Regional Simulation Model (RSM) uses a "pseudo-cell" approach to integrate local hydrology within the context of a regional hydrologic system. A 2-dimensional triangulated mesh is used to represent the regional surface and ground water systems and a 1-dimensional canal network is superimposed onto this mesh. The movement of water is simulated using a finite volume formulation with a diffusive wave approximation. Each cell in the triangulated mesh has a "pseudo-cell" counterpart, which represents the same area as the cell, but it is conceptualized such that it simulates the localized hydrologic conditions Protocols have been established to provide an interface between a cell and its pseudo-cell counterpart. . A number of pseudo-cell types have already been developed and tested in the simulation of Water Conservation Area 1 and several have been proposed to deal with specific local issues in the Southwest Florida Feasibility Study. This presentation will provide an overview of the overall RSM design, describe the relationship between cells and pseudo-cells, and illustrate how pseudo-cells are be used to simulate agriculture, urban and wetland hydrology.

Van Zee, R. J.; Lal, W. A.

2002-05-01

24

Remote sensing applications to hydrologic modeling  

NASA Technical Reports Server (NTRS)

An energy balance snowmelt model for rugged terrain was devised and coupled to a flow model. A literature review of remote sensing applications to hydrologic modeling was included along with a software development outline.

Dozier, J.; Estes, J. E.; Simonett, D. S.; Davis, R.; Frew, J.; Marks, D.; Schiffman, K.; Souza, M.; Witebsky, E.

1977-01-01

25

The skill of seasonal ensemble low flow forecasts for four different hydrological models  

NASA Astrophysics Data System (ADS)

This paper investigates the skill of 90 day low flow forecasts using two conceptual hydrological models and two data-driven models based on Artificial Neural Networks (ANNs) for the Moselle River. One data-driven model, ANN-Indicator (ANN-I), requires historical inputs on precipitation (P), potential evapotranspiration (PET), groundwater (G) and observed discharge (Q), whereas the other data-driven model, ANN-Ensemble (ANN-E), and the two conceptual models, HBV and GR4J, use forecasted meteorological inputs (P and PET), whereby we employ ensemble seasonal meteorological forecasts. We compared low flow forecasts without any meteorological forecasts as input (ANN-I) and five different cases of seasonal meteorological forcing: (1) ensemble P and PET forecasts; (2) ensemble P forecasts and observed climate mean PET; (3) observed climate mean P and ensemble PET forecasts; (4) observed climate mean P and PET and (5) zero P and ensemble PET forecasts as input for the other three models (GR4J, HBV and ANN-E). The ensemble P and PET forecasts, each consisting of 40 members, reveal the forecast ranges due to the model inputs. The five cases are compared for a lead time of 90 days based on model output ranges, whereas the four models are compared based on their skill of low flow forecasts for varying lead times up to 90 days. Before forecasting, the hydrological models are calibrated and validated for a period of 30 and 20 years respectively. The smallest difference between calibration and validation performance is found for HBV, whereas the largest difference is found for ANN-E. From the results, it appears that all models are prone to over-predict low flows using ensemble seasonal meteorological forcing. The largest range for 90 day low flow forecasts is found for the GR4J model when using ensemble seasonal meteorological forecasts as input. GR4J, HBV and ANN-E under-predicted 90 day ahead low flows in the very dry year 2003 without precipitation data, whereas ANN-I predicted the magnitude of the low flows better than the other three models. The results of the comparison of forecast skills with varying lead times show that GR4J is less skilful than ANN-E and HBV. Furthermore, the hit rate of ANN-E is higher than the two conceptual models for most lead times. However, ANN-I is not successful in distinguishing between low flow events and non-low flow events. Overall, the uncertainty from ensemble P forecasts has a larger effect on seasonal low flow forecasts than the uncertainty from ensemble PET forecasts and initial model conditions.

Demirel, M. C.; Booij, M. J.; Hoekstra, A. Y.

2014-05-01

26

Hydrological model selection: A Bayesian alternative  

NASA Astrophysics Data System (ADS)

The evaluation and comparison of hydrological models has long been a challenge to the practicing hydrological community. No single model can be identified as ideal over the range of possible hydrological situations. With the variety of models available, hydrologic modelers are faced with the problem of determining which model is best applied to a catchment for a particular modeling exercise. The model selection problem is well documented in hydrologic studies, but a broadly applicable as well as theoretically and practically sound method for comparing model performance does not exist in the literature. Bayesian statistical inference, with computations carried out via Markov chain Monte Carlo (MCMC) methods, offers an attractive alternative to conventional model selection methods allowing for the combination of any preexisting knowledge about individual models and their respective parameters with the available catchment data to assess both parameter and model uncertainty. The aim of this study is to present a method by which hydrological models may be compared in a Bayesian framework. The study builds on previous work (Marshall et al., 2004) in which a Bayesian approach implemented using MCMC algorithms was presented as a simple and efficient basis for assessing parameter uncertainty in hydrological models. In this study, a model selection framework is developed in which an adaptive Metropolis algorithm is used to calculate the model's posterior odds. The model used to illustrate our approach is a version of the Australian Water Balance Model (Boughton, 1993) reformulated such that it can have a flexible number of soil moisture storages. To assess the model selection method in a controlled setting, artificial runoff data were created corresponding to a known model configuration. These data were used to evaluate the accuracy of the model selection method and its sensitivity to the size of the sample being used. An application of the Bayesian model identification methodology to 11 years of daily streamflow data from the Murrumbidgee River at Mittagang Crossing in southeastern Australia concludes our study.

Marshall, Lucy; Nott, David; Sharma, Ashish

2005-10-01

27

Covariance Models for Hydrological Applications  

NASA Astrophysics Data System (ADS)

This methodological contribution aims to present some new covariance models with applications in the stochastic analysis of hydrological processes. More specifically, we present explicit expressions for radially symmetric, non-differentiable, Spartan covariance functions in one, two, and three dimensions. The Spartan covariance parameters include a characteristic length, an amplitude coefficient, and a rigidity coefficient which determines the shape of the covariance function. Different expressions are obtained depending on the value of the rigidity coefficient and the dimensionality. If the value of the rigidity coefficient is much larger than one, the Spartan covariance function exhibits multiscaling. Spartan covariance models are more flexible than the classical geostatatistical models (e.g., spherical, exponential). Their non-differentiability makes them suitable for modelling the properties of geological media. We also present a family of radially symmetric, infinitely differentiable Bessel-Lommel covariance functions which are valid in any dimension. These models involve combinations of Bessel and Lommel functions. They provide a generalization of the J-Bessel covariance function, and they can be used to model smooth processes with an oscillatory decay of correlations. We discuss the dependence of the integral range of the Spartan and Bessel-Lommel covariance functions on the parameters. We point out that the dependence is not uniquely specified by the characteristic length, unlike the classical geostatistical models. Finally, we define and discuss the use of the generalized spectrum for characterizing different correlation length scales; the spectrum is defined in terms of an exponent ?. We show that the spectrum values obtained for exponent values less than one can be used to discriminate between mean-square continuous but non-differentiable random fields. References [1] D. T. Hristopulos and S. Elogne, 2007. Analytic properties and covariance functions of a new class of generalized Gibbs random fields, IEEE Transactions on Information Theory, 53(12), 4667 - 4679. [2] D. T. Hristopulos and M. Zukovic, 2011. Relationships between correlation lengths and integral scales for covariance models with more than two parameters, Stochastic Environmental Research and Risk Assessment, 25(1), 11-19. [3] D. T. Hristopulos, 2014. Radial Covariance Functions Motivated by Spatial Random Field Models with Local Interactions, arXiv:1401.2823 [math.ST] .

Hristopulos, Dionissios

2014-05-01

28

ARMA Model identification of hydrologic time series  

Microsoft Academic Search

In recent years, ARMA models have become popular for modeling geophysical time series in general and hydrologic time series in particular. The identification of the appropriate order of the model is an important stage in ARMA modeling. Such model identification is generally based on the autocorrelation and partial autocorrelation functions, although recently improvements have been obtained using the inverse autocorrelation

J. D. Salas; J. T. B. Obeysekera

1982-01-01

29

Effect of different uncertainty sources on the skill of 10 day ensemble low flow forecasts for two hydrological models  

NASA Astrophysics Data System (ADS)

This paper aims to investigate the effect of uncertainty originating from model inputs, parameters and initial conditions on 10 day ensemble low flow forecasts. Two hydrological models, GR4J and HBV, are applied to the Moselle River and performance in the calibration, validation and forecast periods, and the effect of different uncertainty sources on the quality of low flow forecasts are compared. The forecasts are generated by using meteorological ensemble forecasts as input to GR4J and HBV. The ensembles provided the uncertainty range for the model inputs. The Generalized Likelihood Uncertainty Estimation (GLUE) approach is used to estimate parameter uncertainty. The quality of the probabilistic low flow forecasts has been assessed by the relative confidence interval, reliability and hit/false alarm rates. The daily observed low flows are mostly captured by the 90% confidence interval for both models. However, GR4J usually overestimates low flows whereas HBV is prone to underestimate them, particularly when the parameter uncertainty is included in the forecasts. The total uncertainty in GR4J outputs is higher than in HBV. The forecasts issued by HBV incorporating input uncertainty resulted in the most reliable forecast distribution. The parameter uncertainty was the main reason reducing the number of hits. The number of false alarms in GR4J is twice the number of false alarms in HBV when considering all uncertainty sources. The results of this study showed that the parameter uncertainty has the largest effect whereas the input uncertainty had the smallest effect on the medium range low flow forecasts.

Demirel, Mehmet C.; Booij, Martijn J.; Hoekstra, Arjen Y.

2013-07-01

30

Satellite-derived digital elevation model accuracy: hydrological modelling requirements  

Microsoft Academic Search

Hydrological models can benefit from satellite-derived digital elevation models (DEMs) only after determining the hydrological model sensitivity to DEM inaccuracies. This study examined how vertical errors within a SPOT satellite-derived DEM of the 532 km2 Little Washita River, OK, watershed aÄected hydrological predictions in the TOPLATS (topographically based land-atmosphere transfer scheme) water and energy balance model. Model predictions based on

T. A. Endreny; E. F. Wood; D. P. Lettenmaier

2000-01-01

31

INTRODUCTION TO THE INTEGRATED HYDROLOGIC MODEL (IHM)  

Microsoft Academic Search

The public domain Integrated Hydrologic Model (IHM) combines the EPA surface water model HSPF and the USGS groundwater model MODFLOW with near simultaneous integration and fundamentally new interpretations of vadose zone process dynamics. The two model components are concurrently run, linked through an in terface that provides a surface - water to groundwater transition that maintains strict water balance and

Jeff Geurink; Ken Trout; Mark Ross

32

Water Quality Modeling Hydraulics and Hydrology Group  

E-print Network

Water Quality Modeling Cary Troy Hydraulics and Hydrology Group School of Civil Engineering) Thermal Model (DYRESM) Water Quality Model (CAEDYM) Fish Habitat Quality Model (GRP) #12;Examples of lake water quality issues · Dissolved oxygen ­ Low oxygen bottom waters > fish kils · Algal blooms ­ Human

33

On the Use of Models in Hydrology.  

ERIC Educational Resources Information Center

This discussion article addresses the nature of models used in hydrology. It proposes a minimalist classification of models into two categories: models built on data from observations of the processes involved, and those for which there are no observation data on any of these processes, at the scale of interest. (LZ)

de Marsily, G.

1994-01-01

34

High-resolution, multi-scale modeling of watershed hydrology  

E-print Network

High-resolution, multi-scale modeling of watershed hydrology CUAHSI Cyber Seminar October 3, 2003 and Distributed Modeling in a Hydrologic Observatory Assistant Professor of Hydrology Department of Earth and Environmental Science New Mexico Institute of Mining and Technology #12;2 Real and Virtual Hydrologic

Vivoni, Enrique R.

35

ARMA Model Identification of Hydrologic Time Series  

NASA Astrophysics Data System (ADS)

In recent years, ARMA models have become popular for modeling geophysical time series in general and hydrologic time series in particular. The identification of the appropriate order of the model is an important stage in ARMA modeling. Such model identification is generally based on the autocorrelation and partial autocorrelation functions, although recently improvements have been obtained using the inverse autocorrelation and the inverse partial autocorrelation functions. This paper demonstrates the use of the generalized partial autocorrelation function (GPAF) and the R and S functions of Gray et al. (1978) for ARMA model identification of hydrologic time series. These functions are defined, and some recursive relations are given for ease of computation. All three functions, when presented in tabular form, have certain characteristic patterns that are useful in ARMA model identification. Several examples are included to demonstrate the usefulness of the proposed identification technique. Actual applications are made using the Saint Lawrence River and Nile River annual streamflow series.

Salas, J. D.; Obeysekera, J. T. B.

1982-08-01

36

HYDROLOGIC EVALUATION OF LANDFILL PERFORMANCE (HELP) MODEL  

EPA Science Inventory

Hydrologic Evaluation Of Landfill Performance (HELP) model was developed by the US Army Corps of Engineers to facilitate rapid, economic estimation of the amounts of surface runoff, subsurface drainage, and leachate that may be expected to result from the operation of a wide vari...

37

Netherlands Hydrological Modeling Instrument - Unifying Dutch hydrological modeling expertise for national policy analysis  

NASA Astrophysics Data System (ADS)

Dutch hydrological institutes Alterra, Deltares, Netherlands Environmental Assessment Agency and RWS Waterdienst have cooperated to build a new national hydrological model. The instrument will be used by all three ministries involved in national water policy matters, for instance drought management, manure policy and climate change issues. The basis of the modeling instrument is a state-of-the-art on-line coupling of the groundwater system (MODFLOW) and the unsaturated zone (metaSWAP). Optionally a national surface water module (MOZART-DM) can be added, in which surface water distribution, discharge and supply are accounted for. The data for the instrument is derived from several national databases, including the subsoil, groundwater abstractions, topsoil, land use, drainage, water distribution, water management and meteorological data. The Netherlands Hydrological modeling Instrument will be the center point of a framework of models, to coherently model the hydrological system and the multitude of functions it supports. This framework will assist in national policy making. Our ambition is to also make the instrument suitable on a regional and local water board scale. Therefore, for the future refinement of the model, local knowledge of hydrological system needs to be implemented in cooperation with the water boards. The development of the new Netherlands Hydrological modeling Instrument is a quality boost for national water management, thanks to a unique cooperation of all major research institutes and policy makers. It constitutes an essential instrument in implementing the right policy in a changing climate.

Delsman, J.; Kukuric, N.; Veldhuizen, A.; Tiktak, A.; Kroon, T.

2009-04-01

38

TUWmodel: an educational hydrologic model in R  

NASA Astrophysics Data System (ADS)

In order to show the advantages of using hydrologic models in R environment, particularly for educational purposes, we have implemented a conceptual rainfall-runoff model, originally written in Fortran language into R. This hydrologic model is used in many scientific studies and operational engineering applications in Austria. The model consisting of a snow, a soil moisture and a flow routing routine and run on a daily time step in a lumped or a semi-lumped way. The R environment allows to compile and use this model on different platforms and operating system, taking advantage of many additional routines already available in R (i.e. visualisation or optimisation tools). In this poster we present a set of examples that are used in a graduate level course on engineering hydrology at the Vienna University of Technology, which include: - Multi-objective calibration of the model; - Manual vs. automatic calibration; - Visualisation of model outputs and efficiencies; - Model application in ungauged catchments; - Operational runoff forecast. The flexibility of R is ideal for education, since students can easily play with the extensive list of existing functionalities and define new functions and extensions.

Parajka, J.; Rogger, M.; Kobler, U.; Salinas, J.; Nester, T.; Bloeschl, G.

2013-12-01

39

Assimilating GRACE terrestrial water storage data into a conceptual hydrology model for the River Rhine  

NASA Astrophysics Data System (ADS)

Terrestrial water storage (TWS) is a key component of the terrestrial and global hydrological cycles, and plays a major role in the Earth’s climate. The Gravity Recovery and Climate Experiment (GRACE) twin satellite mission provided the first space-based dataset of TWS variations, albeit with coarse resolution and limited accuracy. Here, we examine the value of assimilating GRACE observations into a well-calibrated conceptual hydrology model of the Rhine river basin. In this study, the ensemble Kalman filter (EnKF) and smoother (EnKS) were applied to assimilate the GRACE TWS variation data into the HBV-96 rainfall run-off model, from February 2003 to December 2006. Two GRACE datasets were used, the DMT-1 models produced at TU Delft, and the CSR-RL04 models produced by UT-Austin . Each center uses its own data processing and filtering methods, yielding two different estimates of TWS variations and therefore two sets of assimilated TWS estimates. To validate the results, the model estimated discharge after the data assimilation was compared with measured discharge at several stations. As expected, the updated TWS was generally somewhere between the modeled and observed TWS in both experiments and the variance was also lower than both the prior error covariance and the assumed GRACE observation error. However, the impact on the discharge was found to depend heavily on the assimilation strategy used, in particular on how the TWS increments were applied to the individual storage terms of the hydrology model.

Widiastuti, E.; Steele-Dunne, S. C.; Gunter, B.; Weerts, A.; van de Giesen, N.

2009-12-01

40

Calibrating a spatially distributed conceptual hydrological model using runoff, annual mass balance and winter mass balance  

NASA Astrophysics Data System (ADS)

SummaryWe modified the well-known HBV-ETH model to develop a partially distributed hydrological model that was able to simulate runoff in a highly glacierised basin. By introducing additional calibration criteria (annual and winter glacier mass balance) we reduced the goodness-of-fit for runoff, but improved the description of the accumulation and ablation processes involved. Final adjustment of the model parameters, after choosing the best out of 10,000 random parameter sets, allowed us to find a parameter calibration with acceptable errors for all criteria, which was then confirmed by good model performance during the validation period. The glacier-wide winter mass balance and the annual mass balance in the ablation area were simulated well, while the annual mass balance in the accumulation area showed inaccuracies. Good simulation of the processes during the 2003 heat wave in Europe proved that the model also delivers reliable results for meteorological conditions different from those used during calibration.

Mayr, Elisabeth; Hagg, Wilfried; Mayer, Christoph; Braun, Ludwig

2013-01-01

41

Assessment of The Uncertainties of a Conceptual Hydrologic Model By Using Artificially Generated Flows  

NASA Astrophysics Data System (ADS)

Most of the studies that assess the performance of various calibration techniques have to deal with a certain amount of uncertainty in the calibration data. In this study we tested HBV model calibration procedures in hypothetically ideal conditions under the assumption of no errors in the measured data. This was achieved by creating an artificial time series of the flows created by the HBV model using the parameters obtained from calibrating the measured flows. The artificial flows were then used to replace the original flows in the calibration data, which was then used for testing how calibration procedures can reproduce known model parameters. The results showed that in performing one hundred independent calibration runs of the HBV model, we did not manage to obtain parameters that were almost identical to those used to create the artificial flow data without a certain degree of uncertainty. Although the calibration procedure of the model works properly from a practical point of view, it can be regarded as a demonstration of the equifinality principle, since several parameter sets were obtained which led to equally acceptable or behavioural representations of the observed flows. The study demonstrated that this concept for assessing how uncertain hydrological predictions can be applied in the further development of a model or the choice of calibration method using artificially generated data.

Valent, Peter; Szolgay, Ján; Riverso, Carlo

2012-12-01

42

Towards Better Coupling of Hydrological Simulation Models  

NASA Astrophysics Data System (ADS)

Standards for model interoperability and scientific workflow software provide techniques and tools for coupling hydrological simulation models. However, model builders are yet to realize the benefits of these and continue to write ad hoc implementations and scripts. Three case studies demonstrate different approaches to coupling models, the first using tight interfaces (OpenMI), the second using a scientific workflow system (Trident) and the third using a tailored execution engine (Delft Flood Early Warning System - Delft-FEWS). No approach was objectively better than any other approach. The foremost standard for coupling hydrological models is the Open Modeling Interface (OpenMI), which defines interfaces for models to interact. An implementation of the OpenMI standard involves defining interchange terms and writing a .NET/Java wrapper around the model. An execution wrapper such as OatC.GUI or Pipistrelle executes the models. The team built two OpenMI implementations for eWater Source river system models. Once built, it was easy to swap river system models. The team encountered technical challenges with versions of the .Net framework (3.5 calling 4.0) and with the performance of the execution wrappers when running daily simulations. By design, the OpenMI interfaces are general, leaving significant decisions around the semantics of the interfaces to the implementer. Increasingly, scientific workflow tools such as Kepler, Taverna and Trident are able to replace custom scripts. These tools aim to improve the provenance and reproducibility of processing tasks. In particular, Taverna and the myExperiment website have had success making many bioinformatics workflows reusable and sharable. The team constructed Trident activities for hydrological software including IQQM, REALM and eWater Source. They built an activity generator for model builders to build activities for particular river systems. The models were linked at a simulation level, without any daily time-step feedbacks. There was no obvious way to add daily time-step feedbacks without incurring a considerable performance penalty. The Delft-FEWS system connects hydrological models for flood warnings and forecasts in a workflow system. It provides a range of custom facilities for connecting real-time data services. A Delft-FEWS system was constructed to connect a series of eWater Source hydrological models using the batch forecast mode to orchestrate a time-stepping system. The system coupled a series of river models running daily through a service interface. The implementation did not easily support interoperability with other models; however, using command line calls and the file-system did allow a level of language independence. The case-studies covered the coupling of hydrological models through tight interfaces (OpenMI), broad scientific workflow software (Trident) and a tailored execution engine (Delft-FEWS). We found that no approach was objectively better than any other approach. OpenMI had the most flexible interfaces, Trident the best handling of provenance and Delft-FEWS provided a significant set of tools for ingesting and transforming data. The case studies revealed a need for stable execution wrappers, patterns for efficient cross-language interoperability, targeted semantics for hydrological simulation and better handling of daily simulation.

Penton, D.; Stenson, M.; Leighton, B.; Bridgart, R.

2012-12-01

43

Enhancements for Hydrological Modeling in ESMF  

NASA Astrophysics Data System (ADS)

Hydrological systems connect Earth's global physical phenomena with the local environmental impacts that affect our food, health, finances, and homes. The scales and processes that hydrological modelers must span are reflected in the challenges of developing infrastructure for this community. The basic requirements - the need to assemble and couple model components, the need for efficient I/O, the need for integrated visualization, analysis, and data services - are shared with other domains, such as climate and space weather. Where hydrology goes beyond other domains is in its terrific heterogeneity. The diversity of models, data structures, grids, computing platforms, computing languages, and specialized sub-domains involved is daunting. It's not surprising that the hydrological community has spawned a variety of different integrative efforts and frameworks, with distinctly different approaches. This talk will outline how the Earth System Modeling Framework (ESMF), which began in realm of high performance computing for the climate and weather domain, has begun to address the needs of hydrological modelers. We will describe ESMF's new mesh and observational data stream data structures, which join its structured grids and lower-level, index-space constructs as options for data representation, and the flexible, parallel regridding services that can interpolate data between them. The ESMF team is exploring a service oriented architecture approach to computing language and platform diversity, and to interfacing with other standard frameworks. We have also implemented C interfaces for optimized coupling between C and Fortran codes on traditional high performance computing platforms. To address the variety of components available, distributed communities, and integration with data and other services, ESMF has been exhancing its ability to store and write standard component and field metadata, and to link that metadata with full-service science portals. This enables components to be browsed and linked to the data they ingest and produce. The hope is that these enhancements will facilitate integration with other efforts in the hydrology community, and coupling interfaces to the domains such as weather prediction where ESMF is becoming part of the standard infrastructure.

Deluca, C.; Oehmke, R.; Neckels, D.; Theurich, G.; O'Kuinghttons, R.; de Fainchtein, R.; Murphy, S.; Dunlap, R.

2008-12-01

44

Operational hydrological ensemble forecasts in France, taking into account rainfall and hydrological model uncertainties.  

NASA Astrophysics Data System (ADS)

In operational conditions, the actual quality of meteorological and hydrological forecasts do not allow decision-making in a certain future. In this context, meteorological and hydrological ensemble forecasts allow a better representation of forecasts uncertainties. Compared to classical deterministic forecasts, ensemble forecasts improve the human expertise of hydrological forecasts, which is essential to synthesize available informations, coming from different meteorological and hydrological models and human experience. In this paper, we present a hydrological ensemble forecasting system under development at EDF (French Hydropower Company). Our results were updated, taking into account a longer rainfall forecasts archive. Our forecasting system both takes into account rainfall forecasts uncertainties and hydrological model forecasts uncertainties. Hydrological forecasts were generated using the MORDOR model (Andreassian et al., 2006), developed at EDF and used on a daily basis in operational conditions on a hundred of watersheds. Two sources of rainfall forecasts were used : one is based on ECMWF forecasts, another is based on an analogues approach (Obled et al., 2002). Two methods of hydrological model forecasts uncertainty estimation were used : one is based on the use of equifinal parameter sets (Beven & Binley, 1992), the other is based on the statistical modelisation of the hydrological forecast empirical uncertainty (Montanari et al., 2004 ; Schaefli et al., 2007). Daily operational hydrological 7-day ensemble forecasts during 4 years (from 2005 to 2008) in few alpine watersheds were evaluated. Finally, we present a way to combine rainfall and hydrological model forecast uncertainties to achieve a good probabilistic calibration. Our results show that the combination of ECMWF and analogues-based rainfall forecasts allow a good probabilistic calibration of rainfall forecasts. They show also that the statistical modeling of the hydrological forecast empirical uncertainty has a better probabilistic calibration, than the equifinal parameter set approach. Andreassian et al., 2006. Catalogue of the models used in MOPEX 2004/2005. Large sample basin experiments for hydrological mode parameterisation : results of the Model Parameter Experiment, IAHS Publ. 307, 41-94. Beven & Binley, 1992. The future of distributed models : model calibration and uncertainty prediction. Hydrological Processes, 6, 279-298. Obled, C., Bontron, G., Garçon, R., 2002. Quantitative precipitation forecasts: a statistical adaptation of model outputs though an analogues sorting approach. Atmospheric Research, 63, 303-324. Montanari, A. and Brath, A., (2004). A stochastic approach for assessing the uncertainty of rainfall-runoff simulations. Water Resources Research, 40, W01106, doi:10.1029/2003WR002540. Schaefli, B., Balin Talamba, D. and Musy, A., (2007). Quantifying hydrological modeling errors through a mixture of normal distributions. Journal of Hydrology, 332, 303-315.

Mathevet, T.; Garavaglia, F.; Gailhard, J.; Garçon, R.; Dubus, L.

2009-09-01

45

Integration of Local Hydrology into Regional Hydrologic Simulation Model  

Microsoft Academic Search

South Florida hydrology is dominated by the Central and South Florida (C&SF) Project that is managed to provide flood protection, water supply and environmental protection. A complex network of levees canals and structures provide these services to the individual drainage basins. The landscape varies widely across the C&SF system, with corresponding differences in the way water is managed within each

R. J. Van Zee; W. A. Lal

2002-01-01

46

Hydrology  

ERIC Educational Resources Information Center

The past year saw a re-emphasis on the practical aspects of hydrology due to regional drought patterns, urban flooding, and agricultural and energy demands on water resources. Highlights of hydrologic symposia, publications, and events are included. (MA)

Sharp, John M., Jr.

1978-01-01

47

Distributed Hydrologic Models for Flow Forecasts - Part 1  

NSDL National Science Digital Library

Distributed Hydrologic Models for Flow Forecasts â Part 1 provides a basic description of distributed hydrologic models and how they work. This module is the first in a two-part series focused on the science of distributed models and their applicability in different situations. Presented by Dr. Dennis Johnson, the module begins with a review of hydrologic models, and then examines the differences between lumped and distributed models. It explains how lumped models may be distributed by subdividing the basin and suggests when distributed hydrologic models are most appropriate. Other topics covered include the advantages of physically-based versus conceptual approaches and some strengths and challenges associated with distributed modeling.

Comet

2009-07-28

48

An operational GLS model for hydrologic regression  

USGS Publications Warehouse

Recent Monte Carlo studies have documented the value of generalized least squares (GLS) procedures to estimate empirical relationships between streamflow statistics and physiographic basin characteristics. This paper presents a number of extensions of the GLS method that deal with realities and complexities of regional hydrologic data sets that were not addressed in the simulation studies. These extensions include: (1) a more realistic model of the underlying model errors; (2) smoothed estimates of cross correlation of flows; (3) procedures for including historical flow data; (4) diagnostic statistics describing leverage and influence for GLS regression; and (5) the formulation of a mathematical program for evaluating future gaging activities. ?? 1989.

Tasker, G.D.; Stedinger, J.R.

1989-01-01

49

Hybrid Modelling Approach to Prairie hydrology: Fusing Data-driven and Process-based Hydrological Models  

NASA Astrophysics Data System (ADS)

Modeling the hydrological response in prairie regions, characterized by flat and undulating terrain, and thus, large non-contributing areas, is a known challenge. The hydrological response (runoff) is the combination of the traditional runoff from the hydrologically contributing area and the occasional overflow from the non-contributing area. This study provides a unique opportunity to analyze the issue of fusing the Soil and Water Assessment Tool (SWAT) and Artificial Neural Networks (ANNs) in a hybrid structure to model the hydrological response in prairie regions. A hybrid SWAT-ANN model is proposed, where the SWAT component and the ANN module deal with the effective (contributing) area and the non-contributing area, respectively. The hybrid model is applied to the case study of Moose Jaw watershed, located in southern Saskatchewan, Canada. As an initial exploration, a comparison between ANN and SWAT models is established based on addressing the daily runoff (streamflow) prediction accuracy using multiple error measures. This is done to identify the merits and drawbacks of each modeling approach. It has been found out that the SWAT model has better performance during the low flow periods but with degraded efficiency during periods of high flows. The case is different for the ANN model as ANNs exhibit improved simulation during high flow periods but with biased estimates during low flow periods. The modelling results show that the new hybrid SWAT-ANN model is capable of exploiting the strengths of both SWAT and ANN models in an integrated framrwork. The new hybrid SWAT-ANN model simulates daily runoff quite satisfactorily with NSE measures of 0.80 and 0.83 during calibration and validation periods, respectively. Furthermore, an experimental assessment was performed to identify the effects of the ANN training method on the performance of the hybrid model as well as the parametric identifiability. Overall, the results obtained in this study suggest that the fusion of process-based and data driven models can provide an alternative modelling approach to prairie hydrology. The approach is capable of representing the highly non-linear nature of the hydrological processes and in particular, the challenging response originating from the hydrologically non-contributing areas.

Mekonnen, B.; Nazemi, A.; Elshorbagy, A.; Mazurek, K.; Putz, G.

2012-04-01

50

Modeling hydrologic and ecologic responses using a new eco-hydrological model for identification of droughts  

NASA Astrophysics Data System (ADS)

severely damages water and agricultural resources, and both hydrological and ecological responses are important for its understanding. First, precipitation deficit induces soil moisture deficiency and high plant water stress causing agricultural droughts. Second, hydrological drought characterized by deficit of river discharge and groundwater follows agricultural drought. However, contributions of vegetation dynamics to these processes at basin scale have not been quantified. To address this issue, we develop an eco-hydrological model that can calculate river discharge, groundwater, energy flux, and vegetation dynamics as diagnostic variables at basin scale within a distributed hydrological modeling framework. The model is applied to drought analysis in the Medjerda River basin. From model inputs and outputs, we calculate drought indices for different drought types. The model shows reliable accuracy in reproducing observed river discharge in long-term (19 year) simulation. Moreover, the drought index calculated from the model-estimated annual peak of leaf area index correlates well (correlation coefficient r = 0.89) with the drought index from nationwide annual crop production, which demonstrates that the modeled leaf area index is capable of representing agricultural droughts related to historical food shortages. We show that vegetation dynamics have a more rapid response to meteorological droughts than river discharge and groundwater dynamics in the Medjerda basin because vegetation dynamics are sensitive to soil moisture in surface layers, whereas soil moisture in deeper layers strongly contributes to streamflow and groundwater level. Our modeling framework can contribute to analyze drought progress, although analyses for other climate conditions are needed.

Sawada, Yohei; Koike, Toshio; Jaranilla-Sanchez, Patricia Ann

2014-07-01

51

Evaluating spatial patterns in hydrological modeling  

NASA Astrophysics Data System (ADS)

Recent advances in hydrological modeling towards fully distributed grid based model codes, increased availability of spatially distributed data (remote sensing and intensive field studies) and more computational power allow a shift towards a spatial model evaluation away from the traditional aggregated evaluation. The consideration of spatially aggregated observations, in form of river discharge, in the evaluation process does not ensure a correct simulation of catchment-inherent distributed variables. The integration of spatial data and hydrological models is limited due to a lack of suitable metrics to evaluate similarity of spatial patterns. This study is engaged with the development of a novel set of performance metrics that capture spatial patterns and go beyond global statistics. The metrics are required to be easy, flexible and especially targeted to compare observed and simulated spatial patterns of hydrological variables. Four quantitative methodologies for comparing spatial patterns are brought forward: (1) A fuzzy set approach that incorporates both fuzziness of location and fuzziness of category. (2) Kappa statistic that expresses the similarity between two maps based on a contingency table (error matrix). (3) An extended version of (2) by considering both fuzziness in location and fuzziness in category. (4) Increasing the information content of a single cell by aggregating neighborhood cells at different window sizes; then computing mean and standard deviation. The identified metrics are tested on observed and simulated land surface temperature maps in a groundwater dominated catchment in western Denmark. The observed data originates from the MODIS satellite and MIKE SHE, a coupled and fully distributed hydrological model, serves as the modelling tool. Synthetic land surface temperature maps are generated to further address strengths and weaknesses of the metrics. The metrics are tested in different parameter optimizing frameworks, where they are defined as objective functions individually and collectively. Additionally discharge data, representing a different observational dataset, is included in the optimization process which enables a multi constrained evaluation of the model. This allows testing different optimization frameworks under consideration of observable spatial patterns and discharge data which represents a spatially aggregated catchment observation.

Koch, Julian; Stisen, Simon; Høgh Jensen, Karsten

2014-05-01

52

Attributing spatial patterns of hydrological model performance  

NASA Astrophysics Data System (ADS)

Global hydrological models and land surface models are used to understand and simulate the global terrestrial water cycle. They are, in particular, applied to assess the current state of global water resources, to identify anthropogenic pressures on the global water system, and to assess impacts of global and climate change on water resources. Especially in data-scarce regions, the growing availability of remote sensing products, e.g. GRACE estimates of changes in terrestrial water storage, evaporation or soil moisture estimates, has added valuable information to force and constrain these models as they facilitate the calibration and validation of simulated states and fluxes other than stream flow at large spatial scales. Nevertheless, observed discharge records provide important evidence to evaluate the quality of water availability estimates and to quantify the uncertainty associated with these estimates. Most large scale modelling approaches are constrained by simplified physical process representations and they implicitly rely on the assumption that the same model structure is valid and can be applied globally. It is therefore important to understand why large scale hydrological models perform good or poor in reproducing observed runoff and discharge fields in certain regions, and to explore and explain spatial patterns of model performance. We present an extensive evaluation of the global water model WaterGAP (Water - Global Assessment and Prognosis) to simulate 20th century discharges. The WaterGAP modeling framework comprises a hydrology model and several water use models and operates in its current version, WaterGAP3, on a 5 arc minute global grid and . Runoff generated on the individual grid cells is routed along a global drainage direction map taking into account retention in natural surface water bodies, i.e. lakes and wetlands, as well as anthropogenic impacts, i.e. flow regulation and water abstraction for agriculture, industry and domestic purposes as calculated by the water use models. Simulated discharges for the period 1958-2001 are evaluated against more than 1500 observed discharge records provided by the Global Runoff Data Centre (GRDC). Globally, the selected gauging stations differ substantially in terms of upstream area (3000 -- 3.6 mill sqkm) and their available time series (between 5 and > 100 yrs). We assess the model performance by applying complementary metrics such as Nash-Sutcliffe-Efficiency or water balance related coefficients. Moreover, based on these metrics, we investigate if and how physiographic catchment characteristics and climate conditions impact model efficiency and identify possible underlying determinants of spatial patterns of model performance.

Eisner, S.; Malsy, M.; Flörke, M.

2013-12-01

53

Hydrological change detection using modeling: Half a century of runoff from four rivers in the Blue Nile Basin  

NASA Astrophysics Data System (ADS)

Land cover changes can have significant impacts on hydrological regime. The objective of this study was to detect possible hydrological changes of four watersheds in the Blue Nile Basin using a model-based method for hydrological change detection. The four watersheds, Birr, Upper-Didesa, Gilgel Abbay, and Koga range in size from 260 to 1800 km2. The changes were assessed based on model parameters, model residuals, and in the overall function of the watersheds in transferring rainfall into runoff. The entire time series (1960-2004) was divided into three periods based on political and land management policy changes. A conceptual rainfall-runoff model, the HBV (Hydrologiska Byråns Vattenbalansavdelning) model, was used for the analysis, and suitable parameter sets for each period were found based on a Monte Carlo approach. The values of six out of nine parameters changed significantly between the periods. Model residuals also showed significant changes between the three periods in three of the four watersheds. On the other hand, the overall functioning of the watersheds in processing rainfall to runoff changed little. So even though the individual parameters and model residuals were changing, the integrated functioning of the watersheds showed minimal changes. This study demonstrated the value of using different approaches for detecting hydrological change and highlighted the sensitivity of the outcome to the applied modeling and statistical methods.

Gebrehiwot, Solomon Gebreyohannis; Seibert, Jan; Gärdenäs, Annemieke I.; Mellander, Per-Erik; Bishop, Kevin

2013-06-01

54

Hydrological model uncertainty assessment in southern Africa  

NASA Astrophysics Data System (ADS)

The importance of hydrological uncertainty analysis has been emphasized in recent years and there is an urgent need to incorporate uncertainty estimation into water resources assessment procedures used in the southern Africa region. The region is characterized by a paucity of accurate data and limited human resources, but the need for informed development decisions is critical to social and economic development. One of the main sources of uncertainty is related to the estimation of the parameters of hydrological models. This paper proposes a framework for establishing parameter values, exploring parameter inter-dependencies and setting parameter uncertainty bounds for a monthly time-step rainfall-runoff model (Pitman model) that is widely used in the region. The method is based on well-documented principles of sensitivity and uncertainty analysis, but recognizes the limitations that exist within the region (data scarcity and accuracy, model user attitudes, etc.). Four example applications taken from different climate and physiographic regions of South Africa illustrate that the methods are appropriate for generating behavioural stream flow simulations which include parameter uncertainty. The parameters that dominate the model response and their degree of uncertainty vary between regions. Some of the results suggest that the uncertainty bounds will be too wide for effective water resources decision making. Further work is required to reduce some of the subjectivity in the methods and to investigate other approaches for constraining the uncertainty. The paper recognizes that probability estimates of uncertainty and methods to include input climate data uncertainties need to be incorporated into the framework in the future.

Hughes, D. A.; Kapangaziwiri, E.; Sawunyama, T.

2010-06-01

55

Reality and fiction of models and data in soil hydrology  

Microsoft Academic Search

The objective of this paper is to contribute to the ongoing discussion on strengths, weaknesses, opportunities and trends of existing modeling approaches in soil hydrology. In modern hydrology, complexity of models and detail of data grow at increasing pace. The prevailing attitude has been that if a model is comprehensive enough, it should be possible to represent the site uniqueness

Y. A. Pachepsky; K. R. J. Smettem; J. Vanderborght; M. Herbst; H. Vereecken; J. H. M. Wösten

2004-01-01

56

Analyzing Spatio-Temporal Hydrological Processes and Related Gradients to Improve Hydrological Modeling in High Mountains  

Microsoft Academic Search

\\u000a Mountain hydrology suffers from insufficient data availability and partly coarse process understanding. But the improvement\\u000a of our process knowledge is the key to manage the mountain water resources in present and future. Hydrological models like\\u000a WaSiM-ETH are used to simulate the water balance in areas were less data are available. The validation and estimation of (un-)certainties\\u000a of the model are

Ole Rößler; Jörg Löffler

2010-01-01

57

Modelling the hydrological cycle in assessments of climate change  

NASA Technical Reports Server (NTRS)

The predictions of climate change studies depend crucially on the hydrological cycles embedded in the different models used. It is shown here that uncertainties in hydrological processes and inconsistencies in both climate and impact models limit confidence in current assessments of climate change. A future course of action to remedy this problem is suggested.

Rind, D.; Rosenzweig, C.; Goldberg, R.

1992-01-01

58

HYDROLOGICAL MODELLING OF MARANHÃO AND PRACANA BASINS, A FIRST APPROACH  

Microsoft Academic Search

Modelling the hydrology of hydrographic basins has shown itself as a useful tool in environment management. The hydrological models can be used for multiple purposes: estimate runoff from sequences of rainfall, access stream water quality, quantify the diffuse pollution that reaches water masses such as estuaries, rivers and lakes, etc. This study has as final objective to simulate and analyse

A. Venâncio; F. Martins; R. Neves

59

A RETROSPECTIVE ANALYSIS OF MODEL UNCERTAINTY FOR FORECASTING HYDROLOGIC CHANGE  

EPA Science Inventory

GIS-based hydrologic modeling offers a convenient means of assessing the impacts associated with land-cover/use change for environmental planning efforts. Alternative future scenarios can be used as input to hydrologic models and compared with existing conditions to evaluate pot...

60

Updating of states in operational hydrological models  

NASA Astrophysics Data System (ADS)

Operationally the main purpose of hydrological models is to provide runoff forecasts. The quality of the model state and the accuracy of the weather forecast together with the model quality define the runoff forecast quality. Input and model errors accumulate over time and may leave the model in a poor state. Usually model states can be related to observable conditions in the catchment. Updating of these states, knowing their relation to observable catchment conditions, influence directly the forecast quality. Norway is internationally in the forefront in hydropower scheduling both on short and long terms. The inflow forecasts are fundamental to this scheduling. Their quality directly influence the producers profit as they optimize hydropower production to market demand and at the same time minimize spill of water and maximize available hydraulic head. The quality of the inflow forecasts strongly depends on the quality of the models applied and the quality of the information they use. In this project the focus has been to improve the quality of the model states which the forecast is based upon. Runoff and snow storage are two observable quantities that reflect the model state and are used in this project for updating. Generally the methods used can be divided in three groups: The first re-estimates the forcing data in the updating period; the second alters the weights in the forecast ensemble; and the third directly changes the model states. The uncertainty related to the forcing data through the updating period is due to both uncertainty in the actual observation and to how well the gauging stations represent the catchment both in respect to temperatures and precipitation. The project looks at methodologies that automatically re-estimates the forcing data and tests the result against observed response. Model uncertainty is reflected in a joint distribution of model parameters estimated using the Dream algorithm.

Bruland, O.; Kolberg, S.; Engeland, K.; Gragne, A. S.; Liston, G.; Sand, K.; Tøfte, L.; Alfredsen, K.

2012-04-01

61

Hydrology  

ERIC Educational Resources Information Center

Lists many recent research projects in hydrology, including flow in fractured media, improvements in remote-sensing techniques, effects of urbanization on water resources, and developments in drainage basins. (MLH)

Sharp, John M.

1977-01-01

62

Hydrological Modelling of Small Catchments Using Swat  

NASA Astrophysics Data System (ADS)

The data from a 142ha catchment in Eastern England(Colworth, Bedfordshire)are be- ing used to investigate the performance of the USDA SWAT software for modelling hydrology of small catchments. Stream flow at the catchment outlet has been mon- itored since October 1999. About 50% of the total catchment is directly controlled within one farm and a rotation of wheat, oil seed rape, grass, linseed, beans and peas is grown. Three years of stream flow and climate data are available. Calibration and validation of stream flow was carried out with both runoff modelling options in the SWAT model (USDA curve number method and the Green and Ampt method). The Nash and Sutcliffe efficiencies for the calibration period were 66% and 63% respec- tively. The performance of SWAT was better in the validation period as a whole, with regard to timing of peaks, baseflow values and Nash and Sutcliffe efficiency. An ef- ficiency of 70% was obtained using the curve number method, which is comparable with the efficiencies obtainable with more complex models. Despite this performance, SWAT is under predicting stream flow peaks. A detailed investigation of important model components, has allowed us to identify some of the reasons for under predic- tion of stream flow peaks.

Kannan, N.; White, S. M.; Worrall, F.; Groves, S.

63

Assimilation of hydrologic and hydrometeorological data into lumped and distributed hydrologic models for improved operational hydrologic forecasting in NWS  

NASA Astrophysics Data System (ADS)

Despite the long history and the renewed interest in recent years, automatic data assimilation in operational hydrology is yet to find widespread acceptance and use at the National Weather Service (NWS) River Forecast Centers (RFCs). To meet the new service needs for uncertainty-quantified high-resolution soil moisture and streamflow information, however, a new paradigm is necessary for operational data assimilation that fully capitalizes on automatic techniques and fast-advancing computing power, and that recognizes, and takes full advantage of, the role of human forecasters in the forecast process. Toward that goal, the NWS Office of Hydrologic Development in collaboration with RFCs and other partners is carrying out a number of data assimilation and related projects. In this talk, we present an overview of these activities in the context of hydrologic ensemble prediction, describe in some detail research, development and research-to-operations transition activities for automatic assimilation of streamflow, soil moisture, precipitation and potential evaporation into lumped and distributed soil moisture accounting and routing models, present results, and identify challenges in assimilating hydrologic and hydrometeorological data toward improving operational hydrologic forecasting.

Seo, D.; Lee, H.; Restrepo, P.

2007-12-01

64

Potential for Remotely Sensed Soil Moisture Data in Hydrologic Modeling  

NASA Technical Reports Server (NTRS)

Many hydrologic processes display a unique signature that is detectable with microwave remote sensing. These signatures are in the form of the spatial and temporal distributions of surface soil moisture and portray the spatial heterogeneity of hydrologic processes and properties that one encounters in drainage basins. The hydrologic processes that may be detected include ground water recharge and discharge zones, storm runoff contributing areas, regions of potential and less than potential ET, and information about the hydrologic properties of soils and heterogeneity of hydrologic parameters. Microwave remote sensing has the potential to detect these signatures within a basin in the form of volumetric soil moisture measurements in the top few cm. These signatures should provide information on how and where to apply soil physical parameters in distributed and lumped parameter models and how to subdivide drainage basins into hydrologically similar sub-basins.

Engman, Edwin T.

1997-01-01

65

Distributed Hydrologic Models for Flow Forecasts - Part 2  

NSDL National Science Digital Library

Distributed Hydrologic Models for Flow Forecasts Part 2 is the second release in a two-part series focused on the science of distributed models and their applicability to different flow forecasting situations. Presented by Dr. Dennis Johnson, the module provides a more detailed look at the processes and mechanisms involved in distributed hydrologic models. It examines the rainfall/runoff component, snowmelt, overland flow routing, and channel response in a basin as represented in a distributed model. Calibration issues and situations in which distributed hydrologic models might be most appropriate are also addressed.

Comet

2010-09-28

66

Modelling impacts of climate change on the hydrology of a Mongolian catchment using an appropriate permafrost conceptualization  

NASA Astrophysics Data System (ADS)

Climate change is expected to have considerable impacts on global water resources. Regional impacts will vary considerably depending on climatological, geographical and hydrological characteristics. A region which is particularly vulnerable to climate change is Central Asia. Precipitation in this area is low and highly variable in space and time, and river discharges are largely dependent on the melting of snow and ice. Changes in temperature and precipitation may seriously affect the timing, duration and intensity of high and low flows and hence water availablity in downstream areas. Mongolia is an example of a country where several of these vulnerable catchments can be found. Permafrost conditions prevail in large parts of the country and have a substantial influence on catchment hydrology, which might be altered by climate change. The objective of this study is to determine the impacts of future climate change on the hydrology of a Mongolian catchment, the Buyant River, taking into account permafrost conditions. This is done in two steps. First, four different permafrost conceptualizations within an existing conceptual hydrological model (HBV) are compared to select the most appropriate one. Two conceptualizations take permafrost into account by only calibrating under non-permafrost (summer) conditions and differ in their elevation representation of the catchment (single and multiple elevation zones). The other two conceptualizations explicitly simulate permafrost conditions by adding freezing and melt functions and an ice store to each of the three water stores of HBV. Five years have been used for calibration and five years for validation. Second, the impact of climate change on the hydrology of the Buyant River is determined by using the outputs of four Global Circulation Models (GCMs) for three SRES emission scenarios in HBV with the most appropriate permafrost conceptualization. The delta change method is used to translate output from GCMs to climate time series for future conditions. Results in the calibration are moderate to good for the conceptualizations with an explicit simulation of permafrost, where the model with one elevation zone performs better in the validation than the model with multiple elevation zones. The other two conceptualizations perform poor to moderate, particularly because groundwater flow persists in winter despite that this period is not considered in the calibration of these cases. The HBV model with explicit permafrost simulation and one elevation zone is used for climate change impact assessment. For the period 2080-2100, the discharge of the Buyant River is likely to increase in spring and most probably will decrease in summer and autumn, for some combinations of GCMs and scenarios considerably. Uncertainties in climate change impacts are large, where the uncertainty due to different GCMs is found to be more important than the uncertainty due to different scenarios. Additionally, uncertainties in downscaling, data and hydrological model structure and parameters can further complicate the analysis of the catchment's response to climate change.

Heerema, Kor; Booij, Martijn J.; Huting, Ric; Warmink, Jord J.; van Beek, Eelco; Jigjsuren, Odgarav

2013-04-01

67

Hydrology  

NASA Astrophysics Data System (ADS)

Water in its different forms has always been a source of wonder, curiosity and practical concern for humans everywhere. Hydrology - An Introduction presents a coherent introduction to the fundamental principles of hydrology, based on the course that Wilfried Brutsaert has taught at Cornell University for the last thirty years. Hydrologic phenomena are dealt with at spatial and temporal scales at which they occur in nature. The physics and mathematics necessary to describe these phenomena are introduced and developed, and readers will require a working knowledge of calculus and basic fluid mechanics. The book will be invaluable as a textbook for entry-level courses in hydrology directed at advanced seniors and graduate students in physical science and engineering. In addition, the book will be more broadly of interest to professional scientists and engineers in hydrology, environmental science, meteorology, agronomy, geology, climatology, oceanology, glaciology and other earth sciences. Emphasis on fundamentals Clarification of the underlying physical processes Applications of fluid mechanics in the natural environment

Brutsaert, Wilfried

2005-08-01

68

From local hydrological process analysis to regional hydrological model application in Benin: Concept, results and perspectives  

NASA Astrophysics Data System (ADS)

This paper presents the concept, first results and perspectives of the hydrological sub-project of the IMPETUS-Benin project which is part of the GLOWA program funded by the German ministry of education and research. In addition to the research concept, first results on field hydrology, pedology, hydrogeology and hydrological modelling are presented, focusing on the understanding of the actual hydrological processes. For analysing the processes a 30 km 2 catchment acting as a super test site was chosen which is assumed to be representative for the entire catchment of about 15,000 km 2. First results of the field investigations show that infiltration, runoff generation and soil erosion strongly depend on land cover and land use which again influence the soil properties significantly. A conceptual hydrogeological model has been developed summarising the process knowledge on runoff generation and subsurface hydrological processes. This concept model shows a dominance of fast runoff components (surface runoff and interflow), a groundwater recharge along preferential flow paths, temporary interaction between surface and groundwater and separate groundwater systems on different scales (shallow, temporary groundwater on local scale and permanent, deep groundwater on regional scale). The findings of intensive measurement campaigns on soil hydrology, groundwater dynamics and soil erosion have been integrated into different, scale-dependent hydrological modelling concepts applied at different scales in the target region (upper Ouémé catchment in Benin, about 15,000 km 2). The models have been applied and successfully validated. They will be used for integrated scenario analyses in the forthcoming project phase to assess the impacts of global change on the regional water cycle and on typical problem complexes such as food security in West African countries.

Bormann, H.; Faß, T.; Giertz, S.; Junge, B.; Diekkrüger, B.; Reichert, B.; Skowronek, A.

69

On the Predictive Uncertainty of a Distributed Hydrologic Model  

E-print Network

-temporal validation). These val- idations assessed the applicability under different scenarios of the model parameters obtained by calibration. The Nash-Sutcliffe coefficient (NS) (Nash and Sutcliffe, 1970) is recommended to assess the performance of hydrologic models...-temporal validation). These val- idations assessed the applicability under different scenarios of the model parameters obtained by calibration. The Nash-Sutcliffe coefficient (NS) (Nash and Sutcliffe, 1970) is recommended to assess the performance of hydrologic models...

Cho, Huidae

2009-05-15

70

Assessing hydrological model behaviors by intercomparison of the simulated stream flow compositions: case study in a steep forest watershed in Taiwan  

NASA Astrophysics Data System (ADS)

The accurate stream flow composition simulated by different models is rarely discussed, and few studies addressed the model behaviors affected by the model structures. This study compared the simulated stream flow composition derived from two models, namely HBV and TOPMODEL. A total of 23 storms with a wide rainfall spectrum were utilized and independent geochemical data (to derive the stream composition using end-member mixing analysis, EMMA) were introduced. Results showed that both hydrological models generally perform stream discharge satisfactory in terms of the Nash efficiency coefficient, correlation coefficient, and discharge volume. However, the three simulated flows (surface flow, interflow, and base flow) derived from the two models were different with the change of storm intensity and duration. Both simulated surface flows showed the same patterns. The HBV simulated base flow dramatically increased with the increase of storm duration. However, the TOP-derived base flow remained stable. Meanwhile, the two models showed contrasting behaviors in the interflow. HBV prefers to generate less interflow but percolates more to the base flow to match the stream flow, which implies that this model might be suited for thin soil layer. The use of the models should consider more environmental background data into account. Compared with the EMMA-derived flows, both models showed a significant 2 to 4 h time lag, indicating that the base-flow responses were faster than the models represented. Our study suggested that model intercomparison under a wide spectrum of rainstorms and with independent validation data (geochemical data) is a good means of studying the model behaviors. Rethinking the characterization of the model structure and the watershed characteristics is necessary in selecting the more appropriate hydrological model.

Huang, J.-C.; Lee, T.-Y.; Lee, J.-Y.; Hsu, S.-C.; Kao, S.-J.; Chang, F.-J.

2013-01-01

71

Uncertainties of the extreme high flows under climate change impact due to emission scenarios, hydrological models and parameters  

NASA Astrophysics Data System (ADS)

Climate change has exerted a significant impact on the hydrological cycle which is closely related to human's daily life. Due to the fact that the extreme precipitation is happening with increasing frequency and intensity, the study of extreme high flows has been an issue of great importance in recent years. Normally the future discharges are simulated by hydrological models with outputs from the RCMs. However the uncertainties are involved in every step of the processes, including GCMs, emission scenarios, downscaling methods, hydrological models and etc. In this study, the uncertainties in extreme high flows originating from greenhouse gas emission scenarios, hydrological model structures and their parameters were evaluated for the Jinhua River basin, East China. The baseline (1961-1990) climate and future (2011-2040) climate for scenario A1B, A2 and B2 were downscaled by the PRECIS Regional Climate Model with a spatial resolution of 50km×50km from the General Circulation Model (GCM). The outputs of the PRECIS (daily temperature and daily precipitation) were bias corrected by a distribution based method and a linear correction method. Three hydrological models (GR4J, HBV and Xinanjiang) were applied to simulate the daily discharge. The parameter uncertainty in hydrological models were taken into account and quantified by means of the Generalized Likelihood Uncertainty Estimation (GLUE) method. The GLUE was applied for each hydrological model in three emission scenarios. In total 30000 parameter sets were randomly generated within the parameter ranges, in which about 10% parameter sets were above the pre-assigned threshold and represented as the parameter uncertainty. The annual maximum discharge was used for the extreme high flow analysis. There was an overestimation for the monthly precipitation in July, August and September and an overestimation of 6.3-7.8 oC for monthly temperature all year round in the PRECIS output. The biases were reduced after bias correction. It is found that the major source of uncertainty is from parameters in hydrological models, followed by the uncertainties from emission scenarios and the hydrological model structures had the smallest uncertainty contribution. The uncertainty intervals become wider as the discharge increased. Compared with the extreme high flows in 1961-1990, those under scenarios A2 and B2 would not change much and there would be a decrease under scenario A1B. As to the uncertainty intervals for different models, sequence of the uncertainty intervals in the extreme high flows from wide to narrow was: HBV, Xinanajing and GR4J. The uncertainties in the extreme high flow assessment cannot be neglected since they could vary from hundreds to thousands cubic millimeters per second contributed by different uncertainty sources. Meanwhile, the uncertainty intervals became larger with an increasing discharge. Key words: climate change; hydrological models; extreme high flows; parameter uncertainty

Tian, Ye; Booij, Martijn; Zhu, Qian; Pan, Suli; Xu, Yue-Ping

2013-04-01

72

Incorporating landscape classifications in hydrological conceptual models A case study for a central European meso-scale catchment  

NASA Astrophysics Data System (ADS)

Landscape classification into meaningful hydrological units has important implications for hydrological modeling. Conceptual hydrological models, such as HBV- type models, are most commonly designed to represent catchments in a lumped or semi-distributed way at best, i.e. treating them as single entities or sometimes accounting for topographical and land cover variability by introducing some level of stratification. These oversimplifications can frequently lead to substantial misrepresentations of flow generating processes in the catchments in question, as feedback processes between topography, land cover and hydrology in different landscape units can arguably lead to distinct hydrological patterns. By making use of readily available topographical information, hydrological units can be identified based on the concept of "Height above Nearest Drainage" (HAND; Rennó et al., 2008; Nobre et al., 2011). These hydrological units are characterized by different distinct hydrological behavior and can thus be assigned different model structures (Savenije, 2010). In this study we classified the Wark Catchment in Grand Duchy of Luxembourg which exhibits three distinct landscape units: plateau, wetland and hillslope using a 5-5 m2 DEM. A revised and extended version of HAND gave preliminary estimates of uncertainty in the landscape unit identification as they were implemented in a stochastic framework. As the transition thresholds between the landscape units are a priori unknown, they were calibrated against landscape units observed in the field using a single probability based objective function. As a result, each grid cell of the DEM was characterized by a certain probability of being a certain landscape unit, producing maps of dominant landscape and therefore hydrological units. The maps of the landscape classification using HAND and slope in a probabilistic framework were then used to determine the proportions of the three individual hydrological response units in the catchment. The classified landscapes were used to assign different model structures to the individual hydrological response units. As an example deep percolation was defined as dominant process for plateaus, rapid subsurface flow as dominant process for hillslopes and saturation overland flow as dominant process for wetlands. The modeled runoffs from each hydrological unit were combined in a parallel set-up to proportionally contribute to the total catchment runoff. The hydrological units are, in addition, linked by a common groundwater reservoir. The parallel hydrological units, although increasing the number of parameters, have the benefit of comparative calibration. As an example, one may consider the lag time of wetland to be shorter than the lag time of water traveling to the outlet from a plateau. Moreover, due to the dominance of forest on hillslopes in this catchment, hillslope interception should be higher than interception on plateaus which are mainly used for agriculture in the Wark catchment. Furthermore fluxes and processes can be compared. For example, actual evaporation from wetland can potentially be higher than other entities within a catchment as wetland is water logged and evaporation thus less supply limited than on plateaus. To include all the comparisons and criteria in calibration, an evolutionary algorithm was used. The algorithm was adapted and applied in a way that in subsequent steps more and more comparative criteria are forced to be satisfied. At the end of the calibration it is expected that all the criteria should be satisfied. Including landscape classification into hydrological models seems to be a powerful tool which not only allows to consider and to make use of crucial feedback processes controlling the evolution of the hydrological system together with the eco-system but may also lead to more detailed information on how a catchment may work than a simple lumped model.

Gharari, S.; Hrachowitz, M.; Fenicia, F.; Savenije, H. H. G.

2012-04-01

73

An open-source distributed mesoscale hydrologic model (mHM)  

NASA Astrophysics Data System (ADS)

The mesoscale hydrological model (mHM) is based on numerical approximations of dominant hydrological processes that have been tested in various hydrological models such as: HBV and VIC. In general, mHM simulates the following processes: canopy interception, snow accumulation and melting, soil moisture dynamics (n-horizons), infiltration and surface runoff, evapotranspiration, subsurface storage and discharge generation, deep percolation and baseflow, and discharge attenuation and flood routing. The main characteristic of mHM is the treatment of the sub-grid variability of input variables and model parameters which clearly distinguishes this model from existing precipitation-runoff models or land surface models. It uses a Multiscale Parameter Regionalization (MPR) to account for the sub-grid variability and to avoid continuous re-calibration. Effective model parameters are location and time dependent (e.g., soil porosity). They are estimated through upscaling operators that link sub-grid morphologic information (e.g., soil texture) with global transfer-function parameters, which, in turn, are found through multi-basin optimization. Global parameters estimated with the MPR technique are quasi-scale invariant and guarantee flux-matching across scales. mHM is an open source code, written in Fortran 2003 (standard), fully modular, with high computational efficiency, and parallelized. It is portable to multiple platforms (Linux, OS X, Windows) and includes a number of algorithms for sensitivity analysis, analysis of parameter uncertainty (MCMC), and optimization (DDS, SA, SCE). All simulated state variables and outputs can be stored as netCDF files for further analysis and visualization. mHM has been evaluated in all major river basins in Germany and over 80 US and 250 European river basins. The model efficiency (NSE) during validation at proxy locations is on average greater than 0.6. During last years, mHM had been used for number of hydrologic applications such as, for example, a) to investigate the influence of the antecedent soil moisture on extreme floods in Germany (2002 and 2013), b) for establishing benchmark agricultural drought events for Germany since 1950. A 60-year reconstruction of the daily mHM soil moisture fields over Germany at high resolution 4 × 4 km2 was used for this purpose, and c) to investigate the potential benefits of a high resolution modeling approach for the drought monitoring and forecasting system over Pan-EU. We invite the community to take advantage of this open-source code which is freely available (after nominal registration) at: http://www.ufz.de/index.php?en=31389.

Samaniego, Luis; Kumar, Rohini; Zink, Matthias; Thober, Stephan; Mai, Juliane; Cuntz, Matthias; Schäfer, David; Schrön, Martin; Musuuza, Jude; Prykhodko, Vladyslav; Dalmasso, Giovanni; Attinger, Sabine; Spieler, Diana; Rakovec, Oldrich; Craven, John; Langenberg, Ben

2014-05-01

74

Hydrological modeling of the Jiaoyi watershed (China) using HSPF model.  

PubMed

A watershed hydrological model, hydrological simulation program-Fortran (HSPF), was applied to simulate the spatial and temporal variation of hydrological processes in the Jiaoyi watershed of Huaihe River Basin, the heaviest shortage of water resources and polluted area in China. The model was calibrated using the years 2001-2004 and validated with data from 2005 to 2006. Calibration and validation results showed that the model generally simulated mean monthly and daily runoff precisely due to the close matching hydrographs between simulated and observed runoff, as well as the excellent evaluation indicators such as Nash-Sutcliffe efficiency (NSE), coefficient of correlation (R (2)), and the relative error (RE). The similar simulation results between calibration and validation period showed that all the calibrated parameters had a certain representation in Jiaoyi watershed. Additionally, the simulation in rainy months was more accurate than the drought months. Another result in this paper was that HSPF was also capable of estimating the water balance components reasonably and realistically in space through the whole watershed. The calibrated model can be used to explore the effects of climate change scenarios and various watershed management practices on the water resources and water environment in the basin. PMID:25013863

Yan, Chang-An; Zhang, Wanchang; Zhang, Zhijie

2014-01-01

75

Hydrological Modeling of the Jiaoyi Watershed (China) Using HSPF Model  

PubMed Central

A watershed hydrological model, hydrological simulation program-Fortran (HSPF), was applied to simulate the spatial and temporal variation of hydrological processes in the Jiaoyi watershed of Huaihe River Basin, the heaviest shortage of water resources and polluted area in China. The model was calibrated using the years 2001–2004 and validated with data from 2005 to 2006. Calibration and validation results showed that the model generally simulated mean monthly and daily runoff precisely due to the close matching hydrographs between simulated and observed runoff, as well as the excellent evaluation indicators such as Nash-Sutcliffe efficiency (NSE), coefficient of correlation (R2), and the relative error (RE). The similar simulation results between calibration and validation period showed that all the calibrated parameters had a certain representation in Jiaoyi watershed. Additionally, the simulation in rainy months was more accurate than the drought months. Another result in this paper was that HSPF was also capable of estimating the water balance components reasonably and realistically in space through the whole watershed. The calibrated model can be used to explore the effects of climate change scenarios and various watershed management practices on the water resources and water environment in the basin. PMID:25013863

Yan, Chang-An; Zhang, Wanchang; Zhang, Zhijie

2014-01-01

76

Hydrological responses to dynamically and statistically downscaled climate model output  

USGS Publications Warehouse

Daily rainfall and surface temperature series were simulated for the Animas River basin, Colorado using dynamically and statistically downscaled output from the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) re-analysis. A distributed hydrological model was then applied to the downscaled data. Relative to raw NCEP output, downscaled climate variables provided more realistic stimulations of basin scale hydrology. However, the results highlight the sensitivity of modeled processes to the choice of downscaling technique, and point to the need for caution when interpreting future hydrological scenarios.

Wilby, R.L.; Hay, L.E.; Gutowski, W.J., Jr.; Arritt, R.W.; Takle, E.S.; Pan, Z.; Leavesley, G.H.; Clark, M.P.

2000-01-01

77

Coupling Quantitative Precipitation Estimate and Great Lakes Hydrologic Models  

E-print Network

Coupling Quantitative Precipitation Estimate and Great Lakes Hydrologic Models Primary Investigator responsible for changes in the Great Lakes aquatic ecosystem; rainfall and associated run-off are those Severe Storms Laboratory (NSSL) and the Great Lakes Environmental Research Laboratory (GLERL

78

Evaluating the performance in the Swedish operational hydrological forecasting systems  

NASA Astrophysics Data System (ADS)

The production of hydrological forecasts generally involves the selection of model(s) and setup, calibration and initialization, verification and updating, generation and evaluation of forecasts. Although, field data are commonly used to calibrate and initiate hydrological models, technological advancements have allowed the use of additional information, i.e. remote sensing data and meteorological ensemble forecasts, to improve hydrological forecasts. However, the precision of hydrological forecasts is often subject to uncertainty related to various components of the production chain and data used. The Swedish Meteorological and Hydrological Institute (SMHI) operationally produces hydrological medium-range forecasts in Sweden using two modeling systems based on the HBV and S-HYPE hydrological models. The hydrological forecasts use both deterministic and ensemble (in total 51 ensemble members which are further reduced to 5 statistical members; 2, 25, 50, 75, 98% percentiles) meteorological forecasts from ECMWF to add information on the uncertainty of the predicted values. In this study, we evaluate the performance of the two operational hydrological forecasting systems and identify typical uncertainties in the forecasting production chain and ways to reduce them. In particular, we investigate the effect of autoregressive updating of the forecasted discharge, and of using the median of the ensemble instead of deterministic forecasts. Medium-range (10 days) hydrological forecasts across 71 selected indicator stations are used. The Kling-Gupta Efficiency and its decomposed terms are used to analyse the performance in different characteristics of the flow signal. Results show that the HBV and S-HYPE models with AR updating are both capable of producing adequate forecasts for a short lead time (1 to 2 days), and the performance steadily decreases in lead time. The autoregressive updating method can improve the performance of the two systems by 30 to 40% in terms of the KGE. This is mainly because the method has a significant impact on the improvement of discharge volume. S-HYPE seems to perform slightly better than HBV in the longer lead time, probably because the S-HYPE system is capable of updating the lake water level, which has an impact on the longer lead times. Moreover, the deterministic and ensemble HBV systems with AR updating perform fairly similar for all lead times. Keywords: Hydrological forecasting, S-HYPE, HBV, Operational production, Kling-Gupta Efficiency, Uncertainty.

Pechlivanidis, Ilias; Bosshard, Thomas; Spångmyr, Henrik; Lindström, Göran; Olsson, Jonas; Arheimer, Berit

2014-05-01

79

The model of the water balance and nutrient uptake as a basis for hydrological, agro-hydrological and other projects  

Microsoft Academic Search

models. The hydrological model can best be based on the water balance, which is a consequence of the law of conservation of matter. The agro-hydrological model is based on the diffusion equation, which leads to the law of limiting factors. The importance of these models is that the underlying principles are generally accepted. Further a wide range of processes can

W. C. Visser

80

New insights for the hydrology of the Rhine based on the new generation climate models  

NASA Astrophysics Data System (ADS)

Decision makers base their choices of adaptation strategies on climate change projections and their associated hydrological consequences. New insights of climate change gained under the new generation of climate models belonging to the IPCC 5th assessment report may influence (the planning of) adaption measures and/or future expectations. In this study, hydrological impacts of climate change as projected under the new generation of climate models for the Rhine were assessed. Hereto we downscaled 31 General Circulation Models (GCMs), which were developed as part of the Coupled Model Intercomparison Project Phase 5 (CMIP5), using an advanced Delta Change Method for the Rhine basin. Changes in mean monthly, maximum and minimum flows at Lobith were derived with the semi-distributed hydrological model HBV of the Rhine. The projected changes were compared to changes that were previously obtained in the trans-boundary project Rheinblick using eight CMIP3 GCMs and Regional Climate Models (RCMs) for emission scenario A1B. All eight selected CMIP3 models (scenario A1B) predicted for 2071-2100 a decrease in mean monthly flows between June and October. Similar decreases were found for some of the 31 CMIP5 models for Representative Concentration Pathways (RCPs) 4.5, 6.0 and 8.5. However, under each RCP, there were also models that projected an increase in mean flows between June and October and on average the decrease was smaller than for the eight CMIP3 models. For 2071-2100, also the mean annual minimum 7-days discharge decreased less in the CMIP5 model simulations than was projected in CMIP3. When assessing the response of mean monthly flows of the CMIP5 simulation with the CSIRO-Mk3-6-0 and HadGEM2-ES models with respect to initial conditions and RCPs, it was found that natural variability plays a dominant role in the near future (2021-2050), while changes in mean monthly flows are dominated by the radiative forcing in the far future (2071-2100). According to RCP 8.5 model simulations, the change in mean monthly flow from May to November may be half the change in mean monthly flow projected by RCP 4.5. From January to March, RCP 8.5 simulations projected higher changes in mean monthly flows than RCP 4.5 simulations. These new insights based on the CMIP5 simulations imply that for the Rhine, the mean and low flow extremes might not decrease as much in summer as was expected under CMIP3. Stresses on water availability during summer are therefore also less than expected from CMIP3.

Bouaziz, Laurène; Sperna Weiland, Frederiek; Beersma, Jules; Buiteveld, Hendrik

2014-05-01

81

Hydrologic Predictions in the Anthropocene: Exploration with Co-evolutionary Socio-hydrologic Models  

NASA Astrophysics Data System (ADS)

Socio-hydrology studies the co-evolution and self-organization of humans in the hydrologic landscape, which requires a thorough understanding of the complex interactions between humans and water. On the one hand, the nature of water availability greatly impacts the development of society. On the other hand, humans can significantly alter the spatio-temporal distribution of water and in this way provide feedback to the society itself. The human-water system functions underlying such complex human-water interactions are not well understood. Exploratory models with the appropriate level of simplification in any given area can be valuable to understand these functions and the self-organization associated with socio-hydrology. In this study, a simple coupled modeling framework for socio-hydrology co-evolution is developed, and is used to illustrate the explanatory power of such models. In the Tarim River, humans depend heavily on agricultural production (other industries can be ignored for a start), and the social processes can be described principally by two variables, i.e., irrigated-area and human population. The eco-hydrological processes are expressed in terms of area under natural vegetation and stream discharge. The study area is the middle and the lower reaches of the Tarim River, which is divided into two modeling units, i.e. middle reach and lower reach. In each modeling unit, four ordinary differential equations are used to simulate the dynamics of the hydrological system represented by stream discharge, ecological system represented by area under natural vegetation, the economic system represented by irrigated area under agriculture and social system represented by human population. The four dominant variables are coupled together by several internal variables. For example, the stream discharge is coupled to irrigated area by the colonization rate and mortality rate of the irrigated area in the middle reach and the irrigated area is coupled to stream discharge by water used for irrigation. In a similar way, the stream discharge and natural vegetation are coupled together. The irrigated area is coupled to population by the colonization rate and mortality rate of the population. The discharge of the lower reach is determined by the discharge from the middle reach. The natural vegetation area in the lower reach is coupled to the discharge in the middle reach by water resources management policy. The co-evolution of the Tarim socio-hydrological system is then analyzed within this modeling framework to gain insights into the overall system dynamics and sensitivity to the external drivers and internal system variables.

Sivapalan, Murugesu; Tian, Fuqiang; Liu, Dengfeng

2013-04-01

82

Coupled Hydrological and Hydraulic Modeling for Flood Mapping  

NASA Astrophysics Data System (ADS)

The delineation of the flooded areas involves both hydrological and hydraulic modeling. Usually, the hydrological and hydraulic processes are separately treated. In the proposed methodology, the coupled modeling of the hydrological and hydraulic processes is used. The calibration and validation of the hydrological parameters is undertaken based on historical floods using the corresponding precipitations for the same period. The calibration process was more complicated in the presence of reservoirs, when not only the discharges downstream but also the water level in the reservoirs had to be accurately reproduced. The time step for precipitation is 1 hour, corresponding to the concentration time of the smallest catchments. The maximum annual precipitation for different time steps (1; 3; 6; 24 hours) were statistically processed and based on these results the cumulative rainfall curves and the synthetic hyetographs were derived. The rainfall duration is depending on the concentration time. Mike 11 with UHM module based on SCS model was used for coupled hydrological and hydraulic modeling. The coupled hydrological and hydraulic simulation for the scaled precipitation leads both at the computation of the components which contribute to the generation of the P% flood at the Hydrometric stations as well as to the determination of the discharge hydrograph along the main river. Based on these results the flood hazard maps were obtained using a DTM based on Lidar data. The methodology was applied for a river basin in Romania of 12500 km2.

Drobot, Radu; Draghia, Aurelian

2014-05-01

83

Hydrologic Modeling Strategy for the Islamic Republic of Mauritania, Africa  

USGS Publications Warehouse

The government of Mauritania is interested in how to maintain hydrologic balance to ensure a long-term stable water supply for minerals-related, domestic, and other purposes. Because of the many complicating and competing natural and anthropogenic factors, hydrologists will perform quantitative analysis with specific objectives and relevant computer models in mind. Whereas various computer models are available for studying water-resource priorities, the success of these models to provide reliable predictions largely depends on adequacy of the model-calibration process. Predictive analysis helps us evaluate the accuracy and uncertainty associated with simulated dependent variables of our calibrated model. In this report, the hydrologic modeling process is reviewed and a strategy summarized for future Mauritanian hydrologic modeling studies.

Friedel, Michael J.

2008-01-01

84

HESS Opinions ``Classification of hydrological models for flood management"  

NASA Astrophysics Data System (ADS)

Hydrological models for flood management are components of flood risk management, which is the set of actions to be taken to prevent flood disasters. It is a cyclical process: initiated by occurrence of an extreme flood it leads through the reconstruction and rehabilitation phase to risk assessment and project planning and implementation, and finally to operation and preparedness for a next extreme flood when the cycle starts again. We subdivide the tasks of flood management into two consecutive parts: planning and operation, which basically require different kinds of hydrological models. For planning, real time runoff is not needed, one works with design scenarios. For this task models should be used appropriate to the tasks at hand, which reflect characteristics of landscape as well as of hydrological scale. For operation, hydrological forecast models are needed which have to meet a different set of conditions. In this paper, requirements for hydrological models as functions of application, geology and topography, and of area size are surveyed and classified, as a first approach for guiding users to the correct type of model to be used in a given location. It is suggested that one always should start flood modeling with an analysis of local conditions and select or develop task and locality specific models.

Plate, E. J.

2009-10-01

85

A sensitivity analysis of regional and small watershed hydrologic models  

NASA Technical Reports Server (NTRS)

Continuous simulation models of the hydrologic behavior of watersheds are important tools in several practical applications such as hydroelectric power planning, navigation, and flood control. Several recent studies have addressed the feasibility of using remote earth observations as sources of input data for hydrologic models. The objective of the study reported here was to determine how accurately remotely sensed measurements must be to provide inputs to hydrologic models of watersheds, within the tolerances needed for acceptably accurate synthesis of streamflow by the models. The study objective was achieved by performing a series of sensitivity analyses using continuous simulation models of three watersheds. The sensitivity analysis showed quantitatively how variations in each of 46 model inputs and parameters affect simulation accuracy with respect to five different performance indices.

Ambaruch, R.; Salomonson, V. V.; Simmons, J. W.

1975-01-01

86

Radar data bias correction implementing quantile mapping and investigation of its influence in a hydrological model  

NASA Astrophysics Data System (ADS)

Weather radar is an important source of data for estimating rainfall rate with relatively high temporal and spatial resolution covering large areas. Although weather radar provides fine temporal and spatial resolution data, it is subject to different sources of error. Beside casual problems associated with radar, e.g. clutter and attenuation, weather radar either underestimates or overestimates the rainfall amount. Additionally, time steps with strangely high values result in destroying the structure of time series derived from radar data. In order to estimate areal precipitation for hydrological analyses, radar data could be merged with rain gauge network data. The merging product quality is strongly dependent on radar data quality. The main purpose of this study is to illustrate a method for improving radar data quality and to investigate the influence of radar data quality on merging products by means of cross validation. Quantile mapping on the two sources of data, the radar and rain gauge network, is implemented in this study to improve the radar data quality. After correcting the radar data, considering rain gauge data as the truth, the data is implemented into a hydrological model, HBV-IWW, to investigate the influence of the different input sources regarding model performance. It has been observed that implementing quantile mapping improves radar data quality significantly. On the other hand, using radar data after correction not only improves interpolation performances but also reveals other possible applications like disaggregation of daily rainfall data into finer temporal resolutions. Beside radar data quality, there are other factors influencing the model performance like network density and the applied interpolation technique. The study area is a mesoscale catchment located in Lower Saxony, northern Germany.

Rabiei, Ehsan; Wallner, Markus; Haberlandt, Uwe

2014-05-01

87

Models of atmosphere-ecosystem-hydrology interactions: Approaches and testing  

NASA Technical Reports Server (NTRS)

Interactions among the atmosphere, terrestrial ecosystems, and the hydrological cycle have been the subject of investigation for many years, although most of the research has had a regional focus. The topic is broad, including the effects of climate and hydrology on vegetation, the effects of vegetation on hydrology, the effects of the hydrological cycle on the atmosphere, and interactions of the cycles via material flux such as solutes and trace gases. The intent of this paper is to identify areas of critical uncertainty, discuss modeling approaches to resolving those problems, and then propose techniques for testing. I consider several interactions specifically to illustrate the range of problems. These areas are as follows: (1) cloud parameterizations and the land surface, (2) soil moisture, and (3) the terrestrial carbon cycle.

Schimel, David S.

1992-01-01

88

Improved Process Representation in a Distributed Hydrological Model  

Microsoft Academic Search

The coupled hydrologic model - land surface scheme WATCLASS is used to simulate spring snowmelt runoff in a small arctic basin dominated by open tundra and shrub tundra vegetation. The model calculates snowmelt rates from a full surface energy balance, while a three layer soil model is used to simulate the infiltration into and the exchange of heat and moisture

B. Davison; S. Pohl; P. Dornes; P. Marsh; A. Pietroniro

2004-01-01

89

Modelling hydrological effects of wetland restoration: a differentiated view.  

PubMed

The paper presents findings of a conjunctive hydrological and ecological study into habitat restoration and catchment hydrology. Physically-based, fully distributed hydrological modelling was coupled with spatial analysis and wetland scenario generation techniques to simulate potential effects of restoring lower, middle, and upper catchment wetlands. In the past, anthropogenic interference of this catchments' landscape for agriculture and settlement has left most wetland areas drained, and brought the natural functioning of the ecosystem into conflict with human needs. Many eco-hydrology studies conclude that such disturbances result in a more extreme hydrological regime. The study objectives were to develop and study innovative methods for habitat restoration, and understand the potential hydrological impacts of each approach. The study aims to analyze the scenarios and whether the hydrological response is influenced by the topological placement of the restoration sites. Land-use change scenarios are developed on the basis of physical characteristics and consider the credibility of transitions from current land-use. This study focused on the position of the wetlands in the catchment and hydrological typology. Wetland restoration scenarios are created for different geographical settings within the catchment. A distinction is made between groundwater dependent wetlands and wetlands that are influenced by in-stream water tables or surface water inundations. Results show that there is little effect on the total annual water budget. The results point to river valley rewetting as having the effect of decreasing the paved overland component of stream flow, and increasing the saturated zone flow component. It promoted groundwater recharge. There was no increase of peak flows due to headwater wetlands, contrary to some sources (Bullock & Acreman 2003). The catchments' actual evapotranspiration and root zone water responses were found to be varied over the analysis points, and were the consequence of a number of factors. As a second conclusion we point out the main knowledge gaps and demerits that could compromise the modelling exercise. Land-use classification for hydrological modelling is subject to important ambiguities. Different maps often have different class definitions and methods for classification. Many in-between land use/land cover types do not fit any particular class definition in map classification. Wetlands were often found to be classified as grassland, leaf forest, or open water. How do we deal with the diversity of wetland types and how to incorporate their specific hydrological behaviour in models? These issues will be thoroughly illustrated for the case of the Grote Nete and put in a larger perspective. PMID:19213997

Staes, J; Rubarenzya, M H; Meire, P; Willems, P

2009-01-01

90

Calibration of a Hydrological Model using Ensemble Satellite Rainfall Inputs  

NASA Astrophysics Data System (ADS)

A combination of satellite rainfall estimates (SRFE) and hydrological models can provide useful information for many remote areas of the planet. However, each component contains its own uncertainties and these uncertainties will interact when SRFE are used as inputs for hydrological models. For any assessment of a coupled system such as this there is a requirement for a comprehensive analysis of all sources of uncertainty, with full consideration of both facets. SRFE have been shown to be useful in many areas that lack the infrastructure to make timely and accurate estimations of rainfall from the ground. Sub-Saharan Africa is typical of this, where a paucity of rain recording radar and sparse gauging networks combine with a highly variable climate and a reliance on rain-fed agriculture. When operating at higher spatial and temporal resolutions, SRFE contain large uncertainties which will propagate through a hydrological model if used as a driving input. This study used a sequential method to produce ensemble SRFE based around the full conditional distribution of recorded rainfall from a sparse, historic raingauge network. The TAMSIM method (introduced by Teo, 2006) was used to produce 200 unique yet equiprobable SRFE, each used as a driver to a downstream hydrological model. Traditional hydrological modelling uses the adjustment of variable parameters within the model to reduce the error between a recorded record of discharge and the modelled one, and many automatic procedures have been produced to refine this calibration process. When SRFE have been used as a driver, little consideration has been paid to this process and often a calibration using the raingauge data has been used, without any consideration to the resulting uncertainty within the hydrological model and its calibration. A similar issue arises when ensemble inputs are used to a hydrological model that has been calibrated using a deterministic estimate of rainfall. This study has shown that such approaches are not suitable for use with ensemble SRFE inputs, and that a calibration approach that incorporates each ensemble input individually and as a whole is required. Finally, the study showed that temporal biases within the SRFE, due to interannual variations of the seasonal rainfall, were directly transferred to the biases in the modelled discharges, yet spatial biases, due to climatic variations across the catchment, where compensated for by the automatic calibration of the hydrological model.

Skinner, Christopher; Bellerby, Timothy

2014-05-01

91

Modelling floods in hydrologically complex lowland river reaches  

Microsoft Academic Search

This paper considers the modelling of lowland river reaches which contain complex within-reach hydrological interactions. It is clear that river and floodplain flow are the most important processes in terms of flood modelling in lowland systems, although there are often important lateral inflows from catchments and hillslopes bounding the floodplain and from interactions between the river and the floodplain, which

M. D. Stewart; P. D. Bates; M. G. Anderson; D. A. Price; T. P. Burt

1999-01-01

92

Surface Hydrology in Global Climate Models: How Good is It?  

Microsoft Academic Search

SUMMARY Land surface schemes are used in general circulation models (GCMs) to simulate the surface processes and the surface-atmosphere interactions. This paper addresses several aspects of land surface modelling from a hydrological perspective. It investigates the e nergy and water fluxes estimated by a typical l and surface scheme (CSIRO9) for the Amazon and Mississippi River Basins, using river runoff

V. K. ARORA; F. H. S. CHIEW; R. B. GRAYSON

1997-01-01

93

MODELING OF THERMALLY DRIVEN HYDROLOGICAL PROCESSES IN PARTIALLY  

E-print Network

such as that originating from the decay of radionuclides. The rationale is then given for numerical modeling being a keyMODELING OF THERMALLY DRIVEN HYDROLOGICAL PROCESSES IN PARTIALLY SATURATED FRACTURED ROCK Y. W to an in- depth understanding of flow and transport processes under strong heat stimulation in fractured

Jellinek, Mark

94

The Use of Simulation Models in Teaching Geomorphology and Hydrology.  

ERIC Educational Resources Information Center

Learning about the physical environment from computer simulation models is discussed in terms of three stages: exploration, experimentation, and calibration. Discusses the effective use of models and presents two computer simulations written in BBC BASIC, STORFLO (for catchment hydrology) and SLOPEK (for hillslope evolution). (Author/GEA)

Kirkby, Mike; Naden, Pam

1988-01-01

95

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

96

Description of the Hydrologic Engineering Center's Hydrologic Modeling System (HEC-HMS) and Application to Watershed Studies  

Microsoft Academic Search

PURPOSE: The objective of this document is to describe the Hydrologic Engineering Center's Hydrologic Modeling System (HEC-HMS) program and its application to watershed studies. HMS has the capability to serve as a cornerstone program with respect to the watershed perspective approach. HMS can simulate the rainfall-runoff at any point within a watershed given physical characteristics of the watershed. It is

Matt Fleming

97

Strategies to eliminate HBV infection  

PubMed Central

Chronic HBV infection is a major public health concern affecting over 240 million people worldwide. Although suppression of HBV replication is achieved in the majority of patients with currently available newer antivirals, discontinuation of therapy prior to hepatitis B surface antigen loss or seroconversion is associated with relapse of HBV in the majority of cases. Thus, new therapeutic modalities are needed to achieve eradication of the virus from chronically infected patients in the absence of therapy. The basis of HBV persistence includes viral and host factors. Here, we review novel strategies to achieve sustained cure or elimination of HBV. The novel approaches include targeting the viral and or host factors required for viral persistence, and novel immune-based therapies, including therapeutic vaccines. PMID:25309617

Kapoor, Rama; Kottilil, Shyam

2014-01-01

98

Legacy model integration for enhancing hydrologic interdisciplinary research  

NASA Astrophysics Data System (ADS)

Many challenges are introduced to interdisciplinary research in and around the hydrologic science community due to advances in computing technology and modeling capabilities in different programming languages, across different platforms and frameworks by researchers in a variety of fields with a variety of experience in computer programming. Many new hydrologic models as well as optimization, parameter estimation, and uncertainty characterization techniques are developed in scripting languages such as Matlab, R, Python, or in newer languages such as Java and the .Net languages, whereas many legacy models have been written in FORTRAN and C, which complicates inter-model communication for two-way feedbacks. However, most hydrologic researchers and industry personnel have little knowledge of the computing technologies that are available to address the model integration process. Therefore, the goal of this study is to address these new challenges by utilizing a novel approach based on a publish-subscribe-type system to enhance modeling capabilities of legacy socio-economic, hydrologic, and ecologic software. Enhancements include massive parallelization of executions and access to legacy model variables at any point during the simulation process by another program without having to compile all the models together into an inseparable 'super-model'. Thus, this study provides two-way feedback mechanisms between multiple different process models that can be written in various programming languages and can run on different machines and operating systems. Additionally, a level of abstraction is given to the model integration process that allows researchers and other technical personnel to perform more detailed and interactive modeling, visualization, optimization, calibration, and uncertainty analysis without requiring deep understanding of inter-process communication. To be compatible, a program must be written in a programming language with bindings to a common implementation of the message passing interface (MPI), which includes FORTRAN, C, Java, the .NET languages, Python, R, Matlab, and many others. The system is tested on a longstanding legacy hydrologic model, the Soil and Water Assessment Tool (SWAT), to observe and enhance speed-up capabilities for various optimization, parameter estimation, and model uncertainty characterization techniques, which is particularly important for computationally intensive hydrologic simulations. Initial results indicate that the legacy extension system significantly decreases developer time, computation time, and the cost of purchasing commercial parallel processing licenses, while enhancing interdisciplinary research by providing detailed two-way feedback mechanisms between various process models with minimal changes to legacy code.

Dozier, A.; Arabi, M.; David, O.

2013-12-01

99

Reducing equifinality of hydrological models by integrating Functional Streamflow Disaggregation  

NASA Astrophysics Data System (ADS)

A universal problem of the calibration of hydrological models is the equifinality of different parameter sets derived from the calibration of models against total runoff values. This is an intrinsic problem stemming from the quality of the calibration data and the simplified process representation by the model. However, discharge data contains additional information which can be extracted by signal processing methods. An analysis specifically developed for the disaggregation of runoff time series into flow components is the Functional Streamflow Disaggregation (FSD; Carl & Behrendt, 2008). This method is used in the calibration of an implementation of the hydrological model SWIM in a medium sized watershed in Thailand. FSD is applied to disaggregate the discharge time series into three flow components which are interpreted as base flow, inter-flow and surface runoff. In addition to total runoff, the model is calibrated against these three components in a modified GLUE analysis, with the aim to identify structural model deficiencies, assess the internal process representation and to tackle equifinality. We developed a model dependent (MDA) approach calibrating the model runoff components against the FSD components, and a model independent (MIA) approach comparing the FSD of the model results and the FSD of calibration data. The results indicate, that the decomposition provides valuable information for the calibration. Particularly MDA highlights and discards a number of standard GLUE behavioural models underestimating the contribution of soil water to river discharge. Both, MDA and MIA yield to a reduction of the parameter ranges by a factor up to 3 in comparison to standard GLUE. Based on these results, we conclude that the developed calibration approach is able to reduce the equifinality of hydrological model parameterizations. The effect on the uncertainty of the model predictions is strongest by applying MDA and shows only minor reductions for MIA. Besides further validation of FSD, the next steps include an extension of the study to different catchments and other hydrological models with a similar structure.

Lüdtke, Stefan; Apel, Heiko; Nied, Manuela; Carl, Peter; Merz, Bruno

2014-05-01

100

Influence of chronic HBV infection on superimposed acute hepatitis E  

PubMed Central

AIM: To investigate the influence of chronic hepatitis B virus (HBV) infection [based on the status of hepatitis B e antigen (HBeAg), HBV DNA, and cirrhosis] on superimposed acute hepatitis E. METHODS: A total of 294 patients were recruited from the Department of Infectious Diseases of the Third Affiliated Hospital, Sun Yat-sen University, from January 2003 to January 2012. The patients were classified into two groups: an HBV + hepatitis E virus (HEV) group (a group with chronic HBV infection that was superinfected with acute hepatitis E, n = 118) and an HEV group (a group with acute hepatitis E, n = 176). We retrospectively analyzed and compared the clinical features of the two groups. Statistical analyses were performed using the ?2 test or Fisher’s exact test for categorical variables and the Student’s t test for continuous variables. A P value < 0.05 was considered statistically significant. RESULTS: The peak values of prothrombin time, serum total bilirubin, and Model for End-Stage Liver Disease scores were significantly higher in the HBV + HEV group. More patients in the HBV + HEV group had complications (39.8% vs 16.5%, P = 0.000) and developed liver failure (35.6% vs 8.5%, P = 0.000). Additionally, the mortality of the HBV + HEV group was significantly higher (20.3% vs 7.4%, P = 0.002). Further analysis of the HBV + HEV group showed that there were no significant differences in complication occurrence, liver failure incidence, or mortality between patients with different HBeAg and HBV DNA statuses. However, in patients with underlying cirrhosis, complication occurrence and liver failure incidence significantly increased. In total, 12.7% of the patients in the HBV + HEV group received anti-HBV treatment, but this therapy failed to reduce mortality in patients who developed liver failure. CONCLUSION: The presence of underlying cirrhosis in chronic HBV infection results in more severe clinical outcomes with superimposed acute hepatitis E. Anti-HBV treatment cannot improve the prognosis of liver failure caused by HBV-HEV superinfection. PMID:24124337

Cheng, Si-Hong; Mai, Li; Zhu, Feng-Qin; Pan, Xing-Fei; Sun, Hai-Xia; Cao, Hong; Shu, Xin; Ke, Wei-Min; Li, Gang; Xu, Qi-Huan

2013-01-01

101

Green roof hydrologic performance and modeling: a review.  

PubMed

Green roofs reduce runoff from impervious surfaces in urban development. This paper reviews the technical literature on green roof hydrology. Laboratory experiments and field measurements have shown that green roofs can reduce stormwater runoff volume by 30 to 86%, reduce peak flow rate by 22 to 93% and delay the peak flow by 0 to 30 min and thereby decrease pollution, flooding and erosion during precipitation events. However, the effectiveness can vary substantially due to design characteristics making performance predictions difficult. Evaluation of the most recently published study findings indicates that the major factors affecting green roof hydrology are precipitation volume, precipitation dynamics, antecedent conditions, growth medium, plant species, and roof slope. This paper also evaluates the computer models commonly used to simulate hydrologic processes for green roofs, including stormwater management model, soil water atmosphere and plant, SWMS-2D, HYDRUS, and other models that are shown to be effective for predicting precipitation response and economic benefits. The review findings indicate that green roofs are effective for reduction of runoff volume and peak flow, and delay of peak flow, however, no tool or model is available to predict expected performance for any given anticipated system based on design parameters that directly affect green roof hydrology. PMID:24569270

Li, Yanling; Babcock, Roger W

2014-01-01

102

Adaptive Modelling of Coupled Hydrological Processes with Application in Water  

E-print Network

and the design of efficient flood protection measures are tasks that engineering companies for water management, given by hyperbolic conservation laws for the water height h and the discharge q th+divq = Sh , tqAdaptive Modelling of Coupled Hydrological Processes with Application in Water Management Peter

103

Adaptive Modelling of Coupled Hydrological Processes with Application in Water  

E-print Network

and the design of efficient flood protection measures are tasks that engineering companies for water management, given by hyperbolic conservation laws for the water height h and the discharge q th +divq = Sh , tqAdaptive Modelling of Coupled Hydrological Processes with Application in Water Management Peter

Kornhuber, Ralf

104

A two-layer model of soil hydrology  

Microsoft Academic Search

A two-layer model of soil hydrology is developed for applications where only limited computer time and complexity are allowed. Volumetric soil water is computed in a thin upper layer for use in calculation of surface evaporation. Storage of water is computed for an underlying deeper layer.

L. Mahrt; H. Pan

1984-01-01

105

Test plan for hydrologic modeling of protective barriers  

SciTech Connect

Pacific Northwest Laboratory prepared this test plan for the Model Applications and Validation Task of the Hanford Protective Barriers Program, which is managed by Westinghouse Hanford Company. The objectives of this plan are to outline the conceptual hydrologic model of protective barriers, discuss the available computer codes, describe the interrelationships between the modeling task and the other tasks of the Protective Barriers Program, present the barrier modeling tests, and estimate the schedule and costs of the hydrologic modeling task for planning purposes by the Protective Barriers Program. The purpose of the tests is to validate models that will be used to confirm the long-term performance of the barrier in minimizing drainage. A second purpose of the tests is to provide information to other parts of the Protective Barriers Program that require such information. 26 refs., 2 figs., 3 tabs.

Fayer, M.J.

1990-03-01

106

Hydrologic Modeling of the Iroquois River Watershed Using HSPF and SWAT  

Microsoft Academic Search

Watershed scale hydrologic simulation models HSPF (Hydrologic Simulation Program - FORTRAN) and SWAT (Soil and Water Assessment Tool) were used to model the hydrology of the 2150 square mile Iroquois River watershed (IRW) located in the east central Illinois. Both models are part of the BASINS modeling system that facilitates pre- and post-processing of data, as well as data input

Jaswinder Singh; H. Vernon Knapp; Misganaw Demissie

2004-01-01

107

An educational model for ensemble streamflow simulation and uncertainty analysis  

NASA Astrophysics Data System (ADS)

This paper presents the hands-on modeling toolbox, HBV-Ensemble, designed as a complement to theoretical hydrology lectures, to teach hydrological processes and their uncertainties. The HBV-Ensemble can be used for in-class lab practices and homework assignments, and assessment of students' understanding of hydrological processes. Using this modeling toolbox, students can gain more insights into how hydrological processes (e.g., precipitation, snowmelt and snow accumulation, soil moisture, evapotranspiration and runoff generation) are interconnected. The educational toolbox includes a MATLAB Graphical User Interface (GUI) and an ensemble simulation scheme that can be used for teaching uncertainty analysis, parameter estimation, ensemble simulation and model sensitivity. HBV-Ensemble was administered in a class for both in-class instruction and a final project, and students submitted their feedback about the toolbox. The results indicate that this educational software had a positive impact on students understanding and knowledge of uncertainty in hydrological modeling.

AghaKouchak, A.; Nakhjiri, N.; Habib, E.

2013-02-01

108

Modeling Soil Depth Based Upon Topographic and Land Cover Attributes to Improve Models of Hydrological Response  

Microsoft Academic Search

Soil depth is an important input parameter in hydrological modeling. Presently, the soil depth data available in national soil databases (STATSGO, SSURGO) is provided as averages within generalized map units. Spatial uncertainty within these units limits their applicability for distributed hydrological modeling in complex terrain. Statistical models were developed for prediction of soil depth in a semiarid mountainous watershed based

T. K. Tesfa; D. G. Tarboton; D. G. Chandler; J. P. McNamara

2008-01-01

109

Is there a need for hydrological modelling in decision support systems for nuclear emergencies.  

PubMed

This paper discusses the role of hydrological modelling in decision support systems for nuclear emergencies. In particular, most recent developments such as, the radionuclide transport models integrated in to the decision support system RODOS will be explored. Recent progress in the implementation of physically-based distributed hydrological models for operational forecasting in national and supranational centres, may support a closer cooperation between national hydrological services and therefore, strengthen the use of hydrological and radiological models implemented in decision support systems. PMID:15238667

Raskob, W; Heling, R; Zheleznyak, M

2004-01-01

110

Variational data assimilation with the YAO platform for hydrological forecasting  

NASA Astrophysics Data System (ADS)

In this study data assimilation based on variational assimilation was implemented with the HBV hydrological model using the YAO platform of University Pierre and Marie Curie (France). The principle of the variational assimilation is to consider the model state variables as control variables and optimise them by minimizing a cost function measuring the disagreement between observations and model simulations. The variational assimilation is used for the hydrological forecasting. In this case four state variables of the rainfall-runoff model HBV (those related to soil water content in the water balance tank and to water contents in rooting tanks) are considered as control variables. They were updated through the 4D-VAR procedure using daily discharge incoming information. The Serein basin in France was studied and a high level of forecasting accuracy was obtained with variational assimilation allowing flood anticipation.

Abbaris, A.; Dakhlaoui, H.; Thiria, S.; Bargaoui, Z.

2014-09-01

111

The application of remote sensing to the development and formulation of hydrologic planning models  

NASA Technical Reports Server (NTRS)

The development of a remote sensing model and its efficiency in determining parameters of hydrologic models are reviewed. Procedures for extracting hydrologic data from LANDSAT imagery, and the visual analysis of composite imagery are presented. A hydrologic planning model is developed and applied to determine seasonal variations in watershed conditions. The transfer of this technology to a user community and contract arrangements are discussed.

Fowler, T. R.; Castruccio, P. A.; Loats, H. L., Jr.

1977-01-01

112

Coevolution and HBV drug resistance.  

PubMed

A high rate of mutation sets a strong foundation for the development of resistance to antiviral drugs. However, the ubiquitous presence of drug resistance mutations in the HBV population does not explain variations in the rate and specific types of drug resistance among patients. These variations can be explained by consideration of coevolution among individual sites in the HBV genome, viral variants and subpopulations, as well as coevolution between the entire intrahost HBV population and the host. The concept of coevolution offers a more complete framework for understanding drug resistance. PMID:20516572

Khudyakov, Yury

2010-01-01

113

A distributed hydrology-vegetation model for complex terrain  

Microsoft Academic Search

A distributed hydrology-vegetation model is described that includes canopy interception, evaporation, transpiration, and snow accumulation and melt, as well as runoff generation via the saturation excess mechanisms. Digital elevation data are used to model topographic controls on incoming solar radiation, air temperature, precipitation, and downslope water movement. Canopy evapotranspiration is represented via a two-layer Penman-Monteith formulation that incorporates local net

Mark S. Wigmosta; D. P. Lettenmaier; L. W. Vail

1994-01-01

114

Dalton Lecture: How far can we go in distributed hydrological modelling?Hydrology and Earth System Sciences, 5(1), 1-12 (2001) EGS How far can we go in distributed hydrological modelling?  

E-print Network

of learning about places. The Dalton Lecture THE 2001 EGS DALTON MEDAL WAS AWARDED TO KEITH JOHN BEVEN FOR HIS1 Dalton Lecture: How far can we go in distributed hydrological modelling?Hydrology and Earth Dalton medallist K.J. Beven is Professor of Hydrology at Lancaster University. He has made fundamental

Paris-Sud XI, Université de

115

Hydrological trend analysis in the Yellow River basin using a distributed hydrological model  

NASA Astrophysics Data System (ADS)

The hydrological cycle has been highly influenced by climate change and human activities, and it is significant for analyzing the hydrological trends that occurred in past decades in order to understand past changes and to predict future trends. The water crisis of the Yellow River basin has drawn much attention from around the world, especially the drying up of the main river along the lower reaches during the 1990s. By incorporating historical meteorological data and available geographic information related to the conditions of the landscape, a distributed hydrological model has been employed to simulate the natural runoff without consideration of artificial water intake. On the basis of the data observed and the results simulated by the model, the hydrological trends have been analyzed quantitatively for evaluating the impact from climate change and human activity. It is found that the simulated natural runoff follows a similar trend as the precipitation in the entire area being studied during the last half century, and this implies that changes in the natural runoff are mainly controlled by the climate change rather than land use change. Changes in actual evapotranspiration upstream of the Lanzhou gauge are controlled by changes in both precipitation and potential evaporation, while changes of actual evapotranspiration downstream of the Lanzhou gauge are controlled mainly by the changes in precipitation. The difference between the annual observed runoff and the simulated runoff indicates that there is little artificial water consumption upstream of the Lanzhou gauge, but the artificial water consumption becomes larger downstream of the Lanzhou gauge. The artificial water consumption shows a significant increasing trend during the past 50 years and is the main cause of the drying up of the Yellow River. However, in contrast to the common perception that the serious drying up downstream of the Yellow River during the 1990s is caused by the rapid increase of artificial water consumption during the same period, it has been found that the main cause of this aggravation is the drier climate that has existed since the 1990s. The main reason that the drying-up situation became better in the 21st century is because of the enhanced water resources management since 2000.

Cong, Zhentao; Yang, Dawen; Gao, Bing; Yang, Hanbo; Hu, Heping

2009-07-01

116

Hydrological Modelling and Parameter Identification for Green Roof  

NASA Astrophysics Data System (ADS)

Green roofs, a multilayered system covered by plants, can be used to replace traditional concrete roofs as one of various measures to mitigate the increasing stormwater runoff in the urban environment. Moreover, facing the high uncertainty of the climate change, the present engineering method as adaptation may be regarded as improper measurements; reversely, green roofs are unregretful and flexible, and thus are rather important and suitable. The related technology has been developed for several years and the researches evaluating the stormwater reduction performance of green roofs are ongoing prosperously. Many European counties, cities in the U.S., and other local governments incorporate green roof into the stormwater control policy. Therefore, in terms of stormwater management, it is necessary to develop a robust hydrologic model to quantify the efficacy of green roofs over different types of designs and environmental conditions. In this research, a physical based hydrologic model is proposed to simulate water flowing process in the green roof system. In particular, the model adopts the concept of water balance, bringing a relatively simple and intuitive idea. Also, the research compares the two methods in the surface water balance calculation. One is based on Green-Ampt equation, and the other is under the SCS curve number calculation. A green roof experiment is designed to collect weather data and water discharge. Then, the proposed model is verified with these observed data; furthermore, the parameters using in the model are calibrated to find appropriate values in the green roof hydrologic simulation. This research proposes a simple physical based hydrologic model and the measures to determine parameters for the model.

Lo, W.; Tung, C.

2012-12-01

117

Scale effects in conceptual hydrological modeling  

Microsoft Academic Search

We simulate the water balance dynamics of 269 catchments in Austria ranging in size from 10 to 130,000 km2 using a semidistributed conceptual model with 11 parameters based on a daily time step. The simulation results suggest that the Nash-Sutcliffe model efficiencies increase over the scale range of 10 and 10,000 km2. The scatter of the model performances decreases with

R. Merz; J. Parajka; G. Blöschl

2009-01-01

118

RECURSIVE PARAMETER ESTIMATION OF HYDROLOGIC MODELS  

EPA Science Inventory

Proposed is a nonlinear filtering approach to recursive parameter estimation of conceptual watershed response models in state-space form. he conceptual model state is augmented by the vector of free parameters which are to be estimated from input-output data, and the extended Kal...

119

A double-layer hydrological model dedicated to glacier sliding  

NASA Astrophysics Data System (ADS)

Field observations show that subglacial hydrology and glacier dynamics are tightly linked. The basal friction law that controls sliding velocities via subglacial water-pressure has been developed but, unfortunately, subglacial water pressure cannot be easily assessed. In the existing physically-based hydrological models, the effective pressure is even set to zero, which prevents from using these models to accurately compute the basal water pressure. In the proposed approach, the water pressure is computed from Darcy's equations for a confined aquifer. These equations are applied to two different layers. The first one features a classical sediment drainage system. The second one, with an appropriate equivalent conductivity, consist of an efficient channel-type drainage system. This second layer is activated when the effective pressure tends toward zero and allows the drainage of the excess of water from the sediment layer. This hydrological model is coupled with a full Stokes ice flow model including a water-pressure dependant friction law used to compute the basal boundary condition. This modelling attempt is first carried out over a synthetic bedrock which is consistent with the specific characteristics of an Antarctic test outlet glacier. These characteristics result from a preliminary survey carried out during the 2007-2009 field seasons on the Astrolabe glacier (Terre Adélie French sector) in the framework of the DACOTA programme.

de Fleurian, B.; Gagliardini, O.; Lemeur, E.; Durand, G.

2009-12-01

120

Chapman Conference on Spatial Variability in Hydrologic Modeling  

NASA Astrophysics Data System (ADS)

The AGU Chapman Conference on Spatial Variability in Hydrologic Modeling was held July 21-23, 1981, at the Colorado State University Pingree Park Campus, located in the mountains some 88.5 km (55 miles) west of Fort Collins, Colorado. The conference was attended by experimentalists and theoreticians from a wide range of disciplines, including geology, hydrology, civil engineering, watershed science, chemical engineering, geography, statistics, mathematics, meteorology, and soil science. The attendees included researchers at various levels of research experience, including a large contingent of graduate students and many senior scientists.The conference goal was to review progress and discuss research approaches to the spatial variability of catchment surface and subsurface properties in a distributed modeling context. Mathematical models of water movement dynamics within a catchment consist of linked partial differential equations that describe free surface flow and unsaturated and saturated flow in porous media. Such models are utilized extensively in attempts to understand and predict the environmental consequences of human activities such as agricultural land management, waste disposal, urbanization, etc. We are concerned with the spatial structure of the parameters in such models, the precipitation input, and the geometric complexity of the system boundaries. The emphasis of this conference was on surface and subsurface hydrological process and their interactions.

Woolhiser, D. A.; Morel-Seytoux, H. J.

121

Model selection techniques for the frequency analysis of hydrological extremes  

NASA Astrophysics Data System (ADS)

The frequency analysis of hydrological extremes requires fitting a probability distribution to the observed data to suitably represent the frequency of occurrence of rare events. The choice of the model to be used for statistical inference is often based on subjective criteria, or it is considered a matter of probabilistic hypotheses testing. In contrast, specific tools for model selection, like the well-known Akaike information criterion (AIC) and the Bayesian information criterion (BIC), are seldom used in hydrological applications. The objective of this study is to verify whether the AIC and BIC work correctly when they are applied to identifying the probability distribution of hydrological extremes, i.e., when the available samples are small and the parent distribution is highly asymmetric. An additional model selection criterion, based on the Anderson-Darling goodness-of-fit test statistic, is here proposed, and the performances of the three methods are compared through an extensive numerical analysis. The capability of the three criteria to recognize the correct parent distribution from the available data samples varies from case to case, and it is rather good in some cases (in particular when the parent is a two-parameter distribution) and unsatisfactory in others. An application to flood peak time series from 1000 catchments located in the United Kingdom provides some further information on the qualities and drawbacks of the considered criteria. From the numerical simulations and data-based analyses it can be concluded that the three model selection techniques considered here produce results of comparable quality.

Laio, Francesco; di Baldassarre, Giuliano; Montanari, Alberto

2009-07-01

122

Eco-hydrological Modeling in the Framework of Climate Change  

NASA Astrophysics Data System (ADS)

A blueprint methodology for studying climate change impacts, as inferred from climate models, on eco-hydrological dynamics at the plot and small catchment scale is presented. Input hydro-meteorological variables for hydrological and eco-hydrological models for present and future climates are reproduced using a stochastic downscaling technique and a weather generator, "AWE-GEN". The generated time series of meteorological variables for the present climate and an ensemble of possible future climates serve as input to a newly developed physically-based eco-hydrological model "Tethys-Chloris". An application of the proposed methodology is realized reproducing the current (1961-2000) and multiple future (2081-2100) climates for the location of Tucson (Arizona). A general reduction of precipitation and a significant increase of air temperature are inferred. The eco-hydrological model is successively applied to detect changes in water recharge and vegetation dynamics for a desert shrub ecosystem, typical of the semi-arid climate of south Arizona. Results for the future climate account for uncertainties in the downscaling and are produced in terms of probability density functions. A comparison of control and future scenarios is discussed in terms of changes in the hydrological balance components, energy fluxes, and indices of vegetation productivity. An appreciable effect of climate change can be observed in metrics of vegetation performance. The negative impact on vegetation due to amplification of water stress in a warmer and dryer climate is offset by a positive effect of carbon dioxide augment. This implies a positive shift in plant capabilities to exploit water. Consequently, the plant water use efficiency and rain use efficiency are expected to increase. Interesting differences in the long-term vegetation productivity are also observed for the ensemble of future climates. The reduction of precipitation and the substantial maintenance of vegetation cover ultimately leads to the depletion of soil moisture and recharge to deeper layers. Such an outcome can affect the long-tem water availability in semi-arid systems and expose plants to more severe and frequent periods of stress.

Fatichi, Simone; Ivanov, Valeriy Y.; Caporali, Enrica

2010-05-01

123

A NEW APPROACH TO HYDROLOGIC MODELING: DERIVED DISTRIBUTIONS REVISITED. (R824780)  

EPA Science Inventory

A fractal geometric procedure to model hydrologic (geophysical) phenomena is introduced. The method consists of using derived distributions, obtained by transforming arbitrary multinomial multifractal measures via fractal interpolating functions, to represent observed hydrologic ...

124

Parameter Differences And Their Impact On Distributed Hydrologic Modeling Using HL RDHM  

Microsoft Academic Search

Improved estimation of a priori gridded parameters is an important element in the development and testing of distributed hydrologic models in the Office of Hydrologic Development (OHD) of the U.S. National Oceanic and Atmospheric Administration's National Weather Service (NOAA\\/NWS). The NWS continues to implement distributed hydrologic modeling to improve water resources and flash flood forecasting capability for the United States.

Z. Zhang; V. Koren; S. Reed; M. Smith; F. Moreda; Y. Zhang

2008-01-01

125

Distributed Hydrologic Modeling Apps for Decision Support in the Cloud  

NASA Astrophysics Data System (ADS)

Advances in computation resources and greater availability of water resources data represent an untapped resource for addressing hydrologic uncertainties in water resources decision-making. The current practice of water authorities relies on empirical, lumped hydrologic models to estimate watershed response. These models are not capable of taking advantage of many of the spatial datasets that are now available. Physically-based, distributed hydrologic models are capable of using these data resources and providing better predictions through stochastic analysis. However, there exists a digital divide that discourages many science-minded decision makers from using distributed models. This divide can be spanned using a combination of existing web technologies. The purpose of this presentation is to present a cloud-based environment that will offer hydrologic modeling tools or 'apps' for decision support and the web technologies that have been selected to aid in its implementation. Compared to the more commonly used lumped-parameter models, distributed models, while being more intuitive, are still data intensive, computationally expensive, and difficult to modify for scenario exploration. However, web technologies such as web GIS, web services, and cloud computing have made the data more accessible, provided an inexpensive means of high-performance computing, and created an environment for developing user-friendly apps for distributed modeling. Since many water authorities are primarily interested in the scenario exploration exercises with hydrologic models, we are creating a toolkit that facilitates the development of a series of apps for manipulating existing distributed models. There are a number of hurdles that cloud-based hydrologic modeling developers face. One of these is how to work with the geospatial data inherent with this class of models in a web environment. Supporting geospatial data in a website is beyond the capabilities of standard web frameworks and it requires the use of additional software. In particular, there are at least three elements that are needed: a geospatially enabled database, a map server, and geoprocessing toolbox. We recommend a software stack for geospatial web application development comprising: MapServer, PostGIS, and 52 North with Python as the scripting language to tie them together. Another hurdle that must be cleared is managing the cloud-computing load. We are using HTCondor as a solution to this end. Finally, we are creating a scripting environment wherein developers will be able to create apps that use existing hydrologic models in our system with minimal effort. This capability will be accomplished by creating a plugin for a Python content management system called CKAN. We are currently developing cyberinfrastructure that utilizes this stack and greatly lowers the investment required to deploy cloud-based modeling apps. This material is based upon work supported by the National Science Foundation under Grant No. 1135482

Swain, N. R.; Latu, K.; Christiensen, S.; Jones, N.; Nelson, J.

2013-12-01

126

How to Reduce Computational Time in Distributed Hydrological Modeling?  

NASA Astrophysics Data System (ADS)

One of the key limitations of distributed hydrologic modeling for large scale simulations of soil moisture and land surface fluxes is the computational time spent in simulating hydrological processes. It is for this reason that applications involving assessment of model uncertainty, or simulating multiple input realizations as often needed to assess climate change impacts on a catchment, are not attempted, and models applied to understand hydrological processes in small sized, experimental catchments. The questions asked in this presentation are (a) whether one can simulate the catchment hydrology by simulating across multiple cross sections in a hillslope ; and (b) can one improve these simulations further by simulating on a single (or selected few) "Equivalent" cross-sections in the catchment. This new concept of an Equivalent Cross-section informed by the catchment landform is developed for upland catchments, to reduce computational time while maintaining the same order of accuracy in simulating hydrologic fluxes. The Unsaturated Soil Moisture Movement model (U3M-2d), based on a 2-dimensional solution of the Richards' equation, is used to simulate hydrologic fluxes. In this method, simulations with U3M-2d are first done for a number of uniformly spaced cross-sections in each Strahler's first order sub-basin and the total fluxes are estimated (reference case). Single or multiple Equivalent Cross-sections are then derived for each Strahler's first order sub-basin and results are compared against the reference case. To formulate the Equivalent Cross-section, the catchment is divided into four major landforms using the methodology developed by Khan et al. [2009] and then a range of weighting schemes for topographic variables and soil types are investigated. The Equivalent Cross-section approach is investigated for seven first order sub-basins of McLaughlin catchment of Snowy River and Wagga Wagga experimental catchment of NSW, Australia. Simulated fluxes by the Equivalent Cross-sections approach are close to the reference fluxes while the computational time is reduced significantly of the order of ~7 to ~10 times. The U3M-2d model evaluation is performed by comparing the simulated soil moisture of hillslope cross-sections with the observed soil moisture at several locations in the Wagga Wagga experimental catchment. Results illustrates that the model has capability to produce consistent results and capture daily soil moisture dynamics. Results from this study indicate that an Equivalent Cross-section based distributed hydrological modeling approach has the potential to reduce the computational time significantly while retaining the same order of accuracy. References Khan, U., A. Sharma, and N. K. Tuteja (2009), A new approach for delineation of hydrologic response units in large catchments, in 18th IMACS World Congress MODSIM 2009, International Conference, Modelling and Simulation Society of Australia and New Zealand, edited by R. S. Anderssen, R.D. Braddock and L.T.H. Newham, pp. 3521-3527, Cairns, Australia.

Khan, U.; Tuteja, N. K.; Ajami, H.; Sharma, A.

2012-12-01

127

Physically Based Mountain Hydrological Modelling using Reanalysis Data in Patagonia  

NASA Astrophysics Data System (ADS)

Remote regions in South America are often characterized by insufficient observations of meteorology for robust hydrological model operation. Yet water resources must be quantified, understood and predicted in order to develop effective water management policies. Here, we developed a physically based hydrological model for a major river in Patagonia using the modular Cold Regions Hydrological Modelling Platform (CRHM) in order to better understand hydrological processes leading to streamflow generation in this remote region. The Baker River -with the largest mean annual streamflow in Chile-, drains snowy mountains, glaciers, wet forests, peat and semi-arid pampas into a large lake. Meteorology over the basin is poorly monitored in that there are no high elevation weather stations and stations at low elevations are sparsely distributed, only measure temperature and rainfall and are poorly maintained. Streamflow in the basin is gauged at several points where there are high quality hydrometric stations. In order to quantify the impact of meteorological data scarcity on prediction, two additional data sources were used: the ERA-Interim (ECMWF Re-analyses) and CFSR (Climate Forecast System Reanalysis) atmospheric reanalyses. Precipitation temporal distribution and magnitude from the models and observations were compared and the reanalysis data was found to have about three times the number of days with precipitation than the observations did. Better synchronization between measured peak streamflows and modeled precipitation was found compared to observed precipitation. These differences are attributed to: (i) lack of any snowfall observations (so precipitation records does not consider snowfall events) and (ii) available rainfall observations are all located at low altitude (<500 m a.s.l), and miss the occurrence of high altitude precipitation events. CRHM parameterization was undertaken by using local physiographic and vegetation characteristics where available and transferring locally unknown hydrological process parameters from cold regions mountain environments in Canada. Some soil moisture parameters were calibrated from streamflow observations. Model performance was estimated through comparison with observed streamflow records. Simulations using observed precipitation had negligible representativeness of streamflow (Nash-Sutcliffe coefficient, NS ? 0.2), while those using any of the two reanalyses as forcing data had reasonable model performance (NS ? 0.7). In spite of the better spatial resolution of the CFSR, the ability to simulate streamflow were not significantly different using either CFSR or ERA-Interim. The modeled water balance shows that snowfall is about 30% of the total precipitation input, but snowmelt superficial runoff comprises about 10% of total runoff. About 75% of all precipitation is infiltrated, and approximately 15% of the losses are attributed to evapotranspiration from soil and lake evaporation.

Krogh, S.; Pomeroy, J. W.; McPhee, J. P.

2013-05-01

128

A Coupled Surface/Subsurface Model for Hydrological Drought Investigations  

NASA Astrophysics Data System (ADS)

Hydrological droughts occur when storage in the ground and surface-water bodies falls below statistical average. Due to the inclusion of regional groundwater, hydrological droughts evolve relatively slowly. The atmospheric and surface components of the hydrological cycle have been widely studied, are well understood, and their prognoses are fairly accurate. In large-scale land surface models on the other hand, subsurface (groundwater) flow processes are usually assumed unidirectional and limited to the vertically-downward percolation and the horizontal runoffs. The vertical feedback from groundwater to the unsaturated zone as well as the groundwater recharge from surface waters are usually misrepresented, resulting in poor model performance during low-flow periods. The feedback is important during meteorological droughts because it replenishes soil moisture from ground- and surface water, thereby delaying the onset of agricultural droughts. If sustained for long periods however, the depletion can significantly reduce surface and subsurface storage and lead to severe hydrological droughts. We hypothesise that an explicit incorporation of the groundwater component into an existing land surface model would lead to better representation of low flows, which is critical for drought analyses. It would also improve the model performance during low-flow periods. For this purpose, we coupled the process-based mHM surface model (Samaniego et al. 2010) with MODFLOW (Harbaugh 2005) to analyse droughts in the Unstrut catchment, one of the tributaries of the Elbe. The catchment is located in one of the most drought-prone areas of Germany. We present results for stand-alone and coupled mHM simulations for the period 1970-2000. References Arlen W. Harbaugh. MODFLOW-2005, The U.S. Geological Survey Modular Ground-water Model-the Ground-water Flow Process, chapter Modelling techniques, sec. A. Ground water, pages 1:1-9:62. USGS, 2005. Luis Samaniego, Rohini Kumar, and Sabine Attinger. Multiscale parameter regionalization of a grid-based hydrologic model at the mesoscale. Water Resour. Res., 46(W05523), 2010. doi: 10.1029/2008WR007327.

Musuuza, J. L.; Kumar, R.; Samaniego, L. E.; Fischer, T.; Kolditz, O.; Attinger, S.

2013-12-01

129

Development of a "Hydrologic Equivalent Wetland" Concept for Modeling Cumulative Effects of Wetlands on Watershed Hydrology  

NASA Astrophysics Data System (ADS)

Wetlands are one of the most important watershed microtopographic features that affect, in combination rather than individually, hydrologic processes (e.g., routing) and the fate and transport of constituents (e.g., sediment and nutrients). Efforts to conserve existing wetlands and/or to restore lost wetlands require that watershed-level effects of wetlands on water quantity and water quality be quantified. Because monitoring approaches are usually cost or logistics prohibitive at watershed scale, distributed watershed models, such as the Soil and Water Assessment Tool (SWAT), can be a best resort if wetlands can be appropriately represented in the models. However, the exact method that should be used to incorporate wetlands into hydrologic models is the subject of much disagreement in the literature. In addition, there is a serious lack of information about how to model wetland conservation-restoration effects using such kind of integrated modeling approach. The objectives of this study were to: 1) develop a "hydrologic equivalent wetland" (HEW) concept; and 2) demonstrate how to use the HEW concept in SWAT to assess effects of wetland restoration within the Broughton's Creek watershed located in southwestern Manitoba of Canada, and of wetland conservation within the upper portion of the Otter Tail River watershed located in northwestern Minnesota of the United States. The HEWs were defined in terms of six calibrated parameters: the fraction of the subbasin area that drains into wetlands (WET_FR), the volume of water stored in the wetlands when filled to their normal water level (WET_NVOL), the volume of water stored in the wetlands when filled to their maximum water level (WET_MXVOL), the longest tributary channel length in the subbasin (CH_L1), Manning's n value for the tributary channels (CH_N1), and Manning's n value for the main channel (CH_N2). The results indicated that the HEW concept allows the nonlinear functional relations between watershed processes and wetland characteristics (e.g., size and morphology) to be accurately represented in the models. The loss of the first 10 to 20% of the wetlands in the Minnesota study area would drastically increase the peak discharge and loadings of sediment, total phosphorus (TP), and total nitrogen (TN). On the other hand, the justifiable reductions of the peak discharge and loadings of sediment, TP, and TN in the Manitoba study area may require that 50 to 80% of the lost wetlands be restored. Further, the comparison between the predicted restoration and conservation effects revealed that wetland conservation seems to deserve a higher priority while both wetland conservation and restoration may be equally important. Moreover, although SWAT was used in this study, the HEW concept is generic and can also be applied with any other hydrologic models.

Wang, X.; Liu, T.; Li, R.; Yang, X.; Duan, L.; Luo, Y.

2012-12-01

130

Distributed Hydrologic Modeling of LID in The Woodlands, Texas  

NASA Astrophysics Data System (ADS)

As early as the 1960s, the Woodlands, TX employed stormwater management similar to modern Low Impact Development (LID) design. Innovative for its time, the master drainage plan attempted to minimize adverse impact to the 100-year floodplain and reduce the impact of development on the natural environment. Today, it is Texas's most celebrated master-planned community. This paper employs the use of NEXRAD radar rainfall in the distributed hydrologic model, VfloTM, to evaluate the effectiveness of The Woodlands master drainage design as a stormwater management technique. Three models were created in order to analyze the rainfall-runoff response of The Woodlands watershed under different development conditions: two calibrated, fully distributed hydrologic models to represent the (A) undeveloped and (B) 2006-development conditions and (C) a hypothetical, highly urbanized model, representing Houston-style development. Parameters, such as imperviousness and land cover, were varied in order to represent the different developed conditions. The A and B models were calibrated using NEXRAD radar rainfall for two recent storm events in 2008 and 2009. All three models were used to compare peak flows, discharge volumes and time to peak of hydrographs for the recent radar rainfall events and a historical gaged rainfall event that occurred in 1974. Results show that compared to pre-developed conditions, the construction of The Woodlands resulted in an average increase in peak flows of only 15% during small storms and 27% during a major event. Furthermore, when compared to the highly urbanized model, peak flows are often two to three times smaller for the 2006-model. In the 2006-model, the peak flow of the 100 year event was successfully attenuated, suggesting that the design of The Woodlands effectively protects the development from the 1% occurrence storm event using LID practices and reservoirs. This study uses a calibrated hydrologic distributed-model supported by NEXRAD radar rainfall to show that innovative LID strategies have been an effective stormwater management technique in The Woodlands, TX.

Bedient, P.; Doubleday, G.; Sebastian, A.; Fang, N.

2012-12-01

131

Resolving structural errors in a spatially distributed hydrologic model  

NASA Astrophysics Data System (ADS)

In hydrological modeling, model structures are developed in an iterative cycle as more and different types of measurements become available and our understanding of the hillslope or watershed improves. However, with increasing complexity of the model, it becomes more and more difficult to detect which parts of the model are deficient, or which processes should also be incorporated into the model during the next development step. In this study, we use two methods (SCEM-UA and SODA) to calibrate a purposely deficient 3-D hillslope-scale model to error-free, artificially generated observations. We use a multi-objective approach based on distributed pressure head at the soil-bedrock interface and hillslope-scale discharge and water balance. SODA's usefulness as a diagnostic methodology is demonstrated by its ability to identify the timing and location of processes that are missing in the model. We further show that SODA's state updates provide information that could readily be incorporated into an improved model structure, and that this type of information cannot be gained from parameter estimation methods such as SCEM-UA. We conclude that SODA can help guide the discussion between experimentalists and modelers by providing accurate and detailed information on how to improve spatially distributed hydrologic models.

Spaaks, J. H.; Bouten, W.

2013-02-01

132

Quantifying and Generalizing Hydrologic Responses to Dam Regulation using a Statistical Modeling Approach  

SciTech Connect

Despite the ubiquitous existence of dams within riverscapes, much of our knowledge about dams and their environmental effects remains context-specific. Hydrology, more than any other environmental variable, has been studied in great detail with regard to dam regulation. While much progress has been made in generalizing the hydrologic effects of regulation by large dams, many aspects of hydrology show site-specific fidelity to dam operations, small dams (including diversions), and regional hydrologic regimes. A statistical modeling framework is presented to quantify and generalize hydrologic responses to varying degrees of dam regulation. Specifically, the objectives were to 1) compare the effects of local versus cumulative dam regulation, 2) determine the importance of different regional hydrologic regimes in influencing hydrologic responses to dams, and 3) evaluate how different regulation contexts lead to error in predicting hydrologic responses to dams. Overall, model performance was poor in quantifying the magnitude of hydrologic responses, but performance was sufficient in classifying hydrologic responses as negative or positive. Responses of some hydrologic indices to dam regulation were highly dependent upon hydrologic class membership and the purpose of the dam. The opposing coefficients between local and cumulative-dam predictors suggested that hydrologic responses to cumulative dam regulation are complex, and predicting the hydrology downstream of individual dams, as opposed to multiple dams, may be more easy accomplished using statistical approaches. Results also suggested that particular contexts, including multipurpose dams, high cumulative regulation by multiple dams, diversions, close proximity to dams, and certain hydrologic classes are all sources of increased error when predicting hydrologic responses to dams. Statistical models, such as the ones presented herein, show promise in their ability to model the effects of dam regulation effects at large spatial scales as to generalize the directionality of hydrologic responses.

McManamay, Ryan A [ORNL

2014-01-01

133

The CRISPR/Cas9 System Facilitates Clearance of the Intrahepatic HBV Templates In Vivo  

PubMed Central

Persistence of hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) under current antiviral therapy is a major barrier to eradication of chronic hepatitis B (CHB). Curing CHB will require novel strategies for specific disruption of cccDNA. The clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system is a newly developed tool for site-specific cleavage of DNA targets directed by a synthetic guide RNA (gRNA) base-paired to the target DNA sequence. To examine whether this system can cleave HBV genomes, we designed eight gRNAs against HBV of genotype A. With the HBV-specific gRNAs, the CRISPR/Cas9 system significantly reduced the production of HBV core and surface proteins in Huh-7 cells transfected with an HBV-expression vector. Among eight screened gRNAs, two effective ones were identified. Interestingly, one gRNA targeting the conserved HBV sequence acted against different genotypes. Using a hydrodynamics-HBV persistence mouse model, we further demonstrated that this system could cleave the intrahepatic HBV genome-containing plasmid and facilitate its clearance in vivo, resulting in reduction of serum surface antigen levels. These data suggest that the CRISPR/Cas9 system could disrupt the HBV-expressing templates both in vitro and in vivo, indicating its potential in eradicating persistent HBV infection. PMID:25137139

Lin, Su-Ru; Yang, Hung-Chih; Kuo, Yi-Ting; Liu, Chun-Jen; Yang, Ta-Yu; Sung, Ku-Chun; Lin, You-Yu; Wang, Hurng-Yi; Wang, Chih-Chiang; Shen, Yueh-Chi; Wu, Fang-Yi; Kao, Jia-Horng; Chen, Ding-Shinn; Chen, Pei-Jer

2014-01-01

134

The CRISPR/Cas9 System Facilitates Clearance of the Intrahepatic HBV Templates In Vivo.  

PubMed

Persistence of hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) under current antiviral therapy is a major barrier to eradication of chronic hepatitis B (CHB). Curing CHB will require novel strategies for specific disruption of cccDNA. The clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system is a newly developed tool for site-specific cleavage of DNA targets directed by a synthetic guide RNA (gRNA) base-paired to the target DNA sequence. To examine whether this system can cleave HBV genomes, we designed eight gRNAs against HBV of genotype A. With the HBV-specific gRNAs, the CRISPR/Cas9 system significantly reduced the production of HBV core and surface proteins in Huh-7 cells transfected with an HBV-expression vector. Among eight screened gRNAs, two effective ones were identified. Interestingly, one gRNA targeting the conserved HBV sequence acted against different genotypes. Using a hydrodynamics-HBV persistence mouse model, we further demonstrated that this system could cleave the intrahepatic HBV genome-containing plasmid and facilitate its clearance in vivo, resulting in reduction of serum surface antigen levels. These data suggest that the CRISPR/Cas9 system could disrupt the HBV-expressing templates both in vitro and in vivo, indicating its potential in eradicating persistent HBV infection. PMID:25137139

Lin, Su-Ru; Yang, Hung-Chih; Kuo, Yi-Ting; Liu, Chun-Jen; Yang, Ta-Yu; Sung, Ku-Chun; Lin, You-Yu; Wang, Hurng-Yi; Wang, Chih-Chiang; Shen, Yueh-Chi; Wu, Fang-Yi; Kao, Jia-Horng; Chen, Ding-Shinn; Chen, Pei-Jer

2014-01-01

135

Parallelization of a hydrological model using the message passing interface  

USGS Publications Warehouse

With the increasing knowledge about the natural processes, hydrological models such as the Soil and Water Assessment Tool (SWAT) are becoming larger and more complex with increasing computation time. Additionally, other procedures such as model calibration, which may require thousands of model iterations, can increase running time and thus further reduce rapid modeling and analysis. Using the widely-applied SWAT as an example, this study demonstrates how to parallelize a serial hydrological model in a Windows® environment using a parallel programing technology—Message Passing Interface (MPI). With a case study, we derived the optimal values for the two parameters (the number of processes and the corresponding percentage of work to be distributed to the master process) of the parallel SWAT (P-SWAT) on an ordinary personal computer and a work station. Our study indicates that model execution time can be reduced by 42%–70% (or a speedup of 1.74–3.36) using multiple processes (two to five) with a proper task-distribution scheme (between the master and slave processes). Although the computation time cost becomes lower with an increasing number of processes (from two to five), this enhancement becomes less due to the accompanied increase in demand for message passing procedures between the master and all slave processes. Our case study demonstrates that the P-SWAT with a five-process run may reach the maximum speedup, and the performance can be quite stable (fairly independent of a project size). Overall, the P-SWAT can help reduce the computation time substantially for an individual model run, manual and automatic calibration procedures, and optimization of best management practices. In particular, the parallelization method we used and the scheme for deriving the optimal parameters in this study can be valuable and easily applied to other hydrological or environmental models.

Wu, Yiping; Li, Tiejian; Sun, Liqun; Chen, Ji

2013-01-01

136

NRCS GeoHydro—A GIS interface for hydrologic modeling  

NASA Astrophysics Data System (ADS)

The US Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) has developed NRCS GeoHydro 9x, a new ArcGIS application, to complement the WinTR-20 application and assist USDA field staff, and other government, private, and foreign organizations. WinTR-20 is a storm event hydrologic model used to evaluate impacts of structural and land treatment measures. NRCS GeoHydro 9x, using geographic information systems (GIS) tools and techniques, performs hydrologic modeling on a drainage area to compute its catchments, drainage points, drainage lines, slope, runoff curve number, longest flow path, time of concentration ( T c), and cross-section details. The application acts as a GIS interface to WinTR-20 by exporting the results of GIS analyses of the drainage area in the input format of WinTR-20. NRCS GeoHydro 9x reinforces the idea that GIS tools and techniques enhance productivity by doing preliminary hydrologic analysis of the drainage area in an objective and accurate manner in a relatively short duration.

Merkel, William H.; Kaushika, Ravichandran M.; Gorman, Eddy

2008-08-01

137

Self-Organizing Basal Hydrology for Ice Sheet Flowline Models  

NASA Astrophysics Data System (ADS)

Subglacial water pressure is a fundamental control on basal drag and glacier sliding rates. However, it has seldom been included as a variable in glacier flow models, mainly due to the great difficulty in calculating water pressure in a realistic yet tractable way. Here we present preliminary results of a simple basal hydrological model designed for coupling to ice sheet flow models. A key feature of the model is that hydraulic conductivity k evolves in response to water discharge Q (which melts ice and increases the capacity of the system) and effective pressure pi - pw (reducing system capacity through ice creep). The timescales of these processes relative to temporal variations in surface water inputs produces contrasting pressure-discharge relationships as an emergent property of the model. Specifically, pw varies directly with Q over diurnal timescales, whereas pw is inversely proportional to Q on seasonal timescales. In combination with suitable friction laws, the hydrology model provides an adaptive basal boundary condition for flowline models. Despite its simplicity, the model allows a rich variety of behaviour to be simulated, including spring 'speed-up' events and summer 'slowdowns'.

Rutt, I. C.; Benn, D.; Cook, S.; Hulton, N. R.

2013-12-01

138

The hydrology of malaria : field observations and mechanistic modeling of the malaria transmission response to environmental climatic variability  

E-print Network

A coupled HYDrology, Entomology and MAlaria Transmission Simulator (HYDREMATS) has been developed. The model simulates the hydrological and climatological determinants of malaria transmission mechanistically and at high ...

Bomblies, Arne

2009-01-01

139

Graduate Opportunities in Earth Systems Modeling and Climate Impacts on Hydrology and Water Resources  

E-print Network

Graduate Opportunities in Earth Systems Modeling and Climate Impacts on Hydrology and Water on hydrology and water resources. Our research focuses on studying the relationship between large scale hydrological processes and climate change in managed and natural ecosystems, water and energy fluxes, land

140

The value of regionalised information for hydrological modelling  

NASA Astrophysics Data System (ADS)

A recurrent problem in hydrology is the absence of runoff data to calibrate conceptual models. This has implications for the reliable application of such models for prediction of streamflow and water resource management. Whilst a large and increasing number of regions are insufficiently gauged, there are also many highly monitored catchments. Transferring the knowledge gained in data-rich areas to ungauged catchments offers possibilities to overcome the absence of runoff observations in data-scarce regions. Here, we transfer knowledge in the form of response signatures, which reflect the hydrological response characteristics of a particular catchment (e.g. runoff ratio and base flow index). A large data set from the Model Parameter Estimation Experiment (MOPEX) is used to regionalise five different response signatures. Observed response signatures are regressed against physical and climatic characteristics of the catchments. Signatures (with uncertainty) for an ungauged location with known physical and climatic characteristics are then estimated utilising the derived relationships. A Bayesian procedure is subsequently used to condition a hydrological model for the target ungauged catchment on the estimated response signatures with formal uncertainty estimation. Particular challenges related to the Bayesian approach include the specification of the prior distribution and the likelihood functions. In this research we introduce and test a method that considers all five regionalised response signatures, where sources of information are not necessarily independent. By explicitly taking account of the inter-signature error covariance structure, regional information is neither neglected nor double-counted. To avoid masking effects of the model structural error, the value of quantity and quality of regionalised information is assessed employing a ';perfect model' approach. Bayes factor is used to evaluate hydrological predictions, as the commonly used performance measures, such as QQ plots or Nash-Sutcliffe, are shown to be unsuitable. Our results demonstrate that the explicit representation of the uncertainty introduced by the regionalisation procedure (including the inter-dependencies between the regionalised signatures) contributes to an improved specification of the optimal model parameter set. Further, it is shown that higher quality (more precise) information leads to a stronger parameter identification. Lastly, the choice of signature is shown to have a strong impact on the estimation of model parameters. Where resources are finite we therefore suggest that modelling should focus initially on those signatures that give the greatest marginal gains for streamflow estimation.

Almeida, S.; Bulygina, N.; McIntyre, N.; Wagener, T.; Buytaert, W.

2013-12-01

141

A Hydrologic and Geomorphic Model of Estuary Breaching and Closure  

NASA Astrophysics Data System (ADS)

Many coastal estuaries are separated seasonally from the ocean by a swash-deposited beach berm. The opening of the inlet may occur by fluvial erosion of the beach berm and closure occurs when sand deposition outpaces erosion of the inlet. To better understand how the hydrology of estuaries affects breaching and closing patterns, a model is developed that incorporates an estuary hydrologic budget with a geormorphic model of the inlet system. When calibrated, the model is able to reproduce the initial seasonal breaching, seasonal closure, intermittent closures and breaches, and the low-streamflow estuary hydrology of the Carmel Lagoon, located in Central California. For two years when the estuary inlet drains directly across the beach-berm in accordance with model assumptions, the calibrated model predicts the observed 48-hour estuary stage amplitude with correlation coefficients of 0.77 and 0.65. For the calibrated model, streamflow is the predominant control on whether the estuary inlet is open or closed. In a series of sensitivity analyses, it is seen that the function of bar-built, coastal estuaries are sensitive to morphologic and hydrologic variations of the beach berm, and changes to the estuary storage itself. By varying individual components of the berm-system and estuary storage, the amount of the time the estuary is open changes -43 - 28% for the 18.2 model period. The morphology of the berm affects barrier groundwater flow, inlet hydraulics, and estuary storage. Importantly, the elevation of the berm determines the volume of water that must enter the estuary in order to breach, and it modulates the wave-overtopping flux. A high berm renders streamflow the predominant control on function and decreases the amount of time that the estuary is open by 4%, whereas a lower berm allows wave-overtopping to contribute to function and increases time open by 24%. By excavating an estuary, it will breach less frequently (-32% change in open) and store water up to 3 months later into the summer. Beach aquifer hydraulic conductivity significantly alters the amount of time the estuary is open or closed; a high hydraulic conductivity berm remains open 43% less than the calibrated model, but a decreased hydraulic conductivity causes only an 11% increase in time open. As a result of sea level rise of 1.67m by 2100, and a beach berm that remains in its current location and accretes vertically, the amount of time the estuary remains open may decrease up to 22%. Model results indicate that the amount of time the estuary is open is more sensitive to changes in wave run-up than the amount of sand deposited in the inlet per each overtopping wave.

Rich, A.; Keller, E. A.

2012-12-01

142

Multi-variable calibration of a semi-distributed hydrological model using streamflow data and satellite-based evapotranspiration  

NASA Astrophysics Data System (ADS)

A procedure is tested to complete energy balance based daily ETa series by MODIS data.The HVB model is calibrated on 2 water balance terms; ETa and stream flow (Q).HBV calibration on Q shows poor ETa results for inter-rainfall and recession periods.Multi-variable (MV) vs. single variable calibration showed best HBV performance.Large volume differences in Q and ETa do not essentially effect MV calibration.

Rientjes, T. H. M.; Muthuwatta, L. P.; Bos, M. G.; Booij, M. J.; Bhatti, H. A.

2013-11-01

143

HBV life cycle is restricted in mouse hepatocytes expressing human NTCP  

PubMed Central

Recent studies have revealed that human sodium taurocholate cotransporting polypeptide (SLC10A1 or NTCP) is a functional cellular receptor for hepatitis B virus (HBV). However, whether human NTCP can support HBV infection in mouse hepatocyte cell lines has not been clarified. Because an HBV-permissible mouse model would be helpful for the study of HBV pathogenesis, it is necessary to investigate whether human NTCP supports the susceptibility of mouse hepatocyte cell lines to HBV. The results show that exogenous human NTCP expression can render non-susceptible HepG2 (human), Huh7 (human), Hepa1–6 (mouse), AML-12 (mouse) cell lines and primary mouse hepatocyte (PMH) cells susceptible to hepatitis D virus (HDV) which employs HBV envelope proteins. However, human NTCP could only introduce HBV susceptibility in human-derived HepG2 and Huh7 cells, but not in mouse-derived Hepa1–6, AML-12 or PMH cells. These data suggest that although human NTCP is a functional receptor that mediates HBV infection in human cells, it cannot support HBV infection in mouse hepatocytes. Our study indicated that the restriction of HBV in mouse hepatocytes likely occurs after viral entry but prior to viral transcription. We have excluded the role of mouse hepatocyte nuclear factors in the restriction of the HBV life cycle and showed that knockdown or inhibition of Sting, TBK1, IRF3 or IRF7, the components of the anti-viral signaling pathways, had no effect on HBV infection in mouse hepatocytes. Therefore, murine restriction factors that limit HBV infection need to be identified before a HBV-permissible mouse line can be created. PMID:24509445

Li, Hanjie; Zhuang, Qiuyu; Wang, Yuze; Zhang, Tianying; Zhao, Jinghua; Zhang, Yali; Zhang, Junfang; Lin, Yi; Yuan, Quan; Xia, Ningshao; Han, Jiahuai

2014-01-01

144

Hydrological trend analysis in the Yellow River basin using a distributed hydrological model  

Microsoft Academic Search

The hydrological cycle has been highly influenced by climate change and human activities, and it is significant for analyzing the hydrological trends that occurred in past decades in order to understand past changes and to predict future trends. The water crisis of the Yellow River basin has drawn much attention from around the world, especially the drying up of the

Zhentao Cong; Dawen Yang; Bing Gao; Hanbo Yang; Heping Hu

2009-01-01

145

Flood modelling in complex hydrologic systems with sparsely resolved data  

NASA Astrophysics Data System (ADS)

The European Directive on Assessment and Management of Flood Risks places significant emphasis on establishing tools suitable for simulating the relevant hydrologic processes in areas of high flood risk. Because flood modelling requires relatively detailed spatial and temporal resolutions, the model selection is controlled by the available distributed hydrologic information. The value of data (mainly stage/discharge records) is indisputable, since the quality of calibration and, consequently, the model predictive capacity, depends on the availability of reliable observations at multiple sites. On the other hand, data scarcity is a global problem in hydrologic engineering that is getting increasingly severe as the monitoring infrastructure is shrinking and degraded. It is therefore crucial to build reliable models that are parsimonious. In this vein, we have adapted the HYDROGEIOS model (Efstratiadis et al., 2008), initially developed as a conjunctive surface-groundwater simulation and water management tool at the monthly time scale, to run in daily time steps. In typical flood simulation packages inputs are time series of precipitation, which are resolved in hourly or finer increment, and detailed hydro-morphologic properties of the stream network. In contrast, the enhanced version of HYDROGEIOS only uses daily rainfall depths and a limited number of parameters that are estimated or calibrated on the basis of once-a-day discharge data. The character of HYDROGEIOS as a conjunctive model enables to represent simultaneously the interactions among the surface and sub-surface processes and the human interventions, and to route the runoff across the stream network. Lacking finely resolved precipitation data and for the purpose of flood routing, we have applied a disaggregation technique to analyse the simulated daily hydrographs in finer time steps. Flood routing is implemented via either a kinematic-wave or a Muskingum diffusive-wave scheme, introducing only one or two parameters per stream reach, respectively. The new version of HYDROGEIOS is being tested on the Boeotikos Kephisos River Basin for flood forecasting in real-time, using as input precipitation forecasts from numerical weather prediction simulations (European project FLASH). The basin is heavily modified, with strong physical heterogeneities, involving multiple peculiarities such as significant karst springs, which rapidly contribute to the streamflow, thus reflecting a strong interaction between surface and ground water processes, and a drainage canal and network in the lower basin with extremely small slopes. Reference Efstratiadis, A., I. Nalbantis, A. Koukouvinos, E. Rozos, and D. Koutsoyiannis, HYDROGEIOS: a semi-distributed GIS-based hydrological model for modified river basins, Hydrol. Earth Syst. Sci., 12, 989-1006, 2008.

Efstratiadis, A.; Mazi, K.; Koussis, A. D.; Koutsoyiannis, D.

2009-04-01

146

Input Variable Selection for Hydrologic Modeling Using Anns  

NASA Astrophysics Data System (ADS)

The use of artificial neural network (ANN) models in water resources applications has grown considerably over the last couple of decades. In learning problems, where a connectionist network is trained with a finite sized training set, better generalization performance is often obtained when unneeded weights in the network are eliminated. One source of unneeded weights comes from the inclusion of input variables that provide little information about the output variables. Hence, in the ANN modeling methodology, one of the approaches that has received little attention, is the selection of appropriate model inputs. In the past, different methods have been used for identifying and eliminating these input variables. Normally, linear methods of Auto Correlation Function (ACF) and Partial Auto Correlation Function (PACF) have been adopted. For nonlinear physical systems e.g. hydrological systems, model inputs selected based on the linear correlation analysis among input and output variables cannot assure to capture the non-linearity in the system. In the present study, two of the non-linear methods have been explored for the Input Variable Selection (IVS). The linear method employing ACF and PACF is also used for comparison purposes. The first non-linear method utilizes a measure of the Mutual Information Criterion (MIC) to characterize the dependence between a potential model input and the output, which is a step wise input selection procedure. The second non-linear method is improvement over the first method which eliminates redundant inputs based on a partial measure of mutual information criterion (PMIC), which is also a step wise procedure. Further, the number of input variables to be considered for the development of ANN model was determined using the Principal Component Analysis (PCA), which previously used to be done by trial and error approach. The daily river flow data derived from Godavari River Basin @ Polavaram, Andhra Pradesh, India, and the daily average rainfall data of three rain gauge stations spatially distributed in Godavari River Basin have been employed to evaluate all the IVS methods for ANN hydrologic model development. Single hidden layer architecture trained using Levenberg-Marquardt algorithm (LMA) has been employed. A wide range of error statistics was used to evaluate the performance of all the models developed with different input selection methods in this study. It has been found that PCA helps to fix the number of input variables to be considered for the model development. The results obtained show that the ANN hydrologic model developed using the inputs based on the first non-linear method performed better than the model developed using the inputs based on the linear method. Further, the ANN hydrologic model developed using the inputs based on the second non-linear method performed the best among all the models developed on various IVS methods investigated in this study. It is recommended that PCA should first be used to determine the number of inputs to be selected and then the second non-linear method should be used to select the specific inputs for the development of ANN hydrologic model.

Ganti, R.; Jain, A.

2011-12-01

147

Genetic Algorithm Optimization of Artificial Neural Networks for Hydrological Modelling  

NASA Astrophysics Data System (ADS)

This paper will consider the case for genetic algorithm optimization in the development of an artificial neural network model. It will provide a methodological evaluation of reported investigations with respect to hydrological forecasting and prediction. The intention in such operations is to develop a superior modelling solution that will be: \\begin{itemize} more accurate in terms of output precision and model estimation skill; more tractable in terms of personal requirements and end-user control; and/or more robust in terms of conceptual and mechanical power with respect to adverse conditions. The genetic algorithm optimization toolbox could be used to perform a number of specific roles or purposes and it is the harmonious and supportive relationship between neural networks and genetic algorithms that will be highlighted and assessed. There are several neural network mechanisms and procedures that could be enhanced and potential benefits are possible at different stages in the design and construction of an operational hydrological model e.g. division of inputs; identification of structure; initialization of connection weights; calibration of connection weights; breeding operations between successful models; and output fusion associated with the development of ensemble solutions. Each set of opportunities will be discussed and evaluated. Two strategic questions will also be considered: [i] should optimization be conducted as a set of small individual procedures or as one large holistic operation; [ii] what specific function or set of weighted vectors should be optimized in a complex software product e.g. timings, volumes, or quintessential hydrological attributes related to the 'problem situation' - that might require the development flood forecasting, drought estimation, or record infilling applications. The paper will conclude with a consideration of hydrological forecasting solutions developed on the combined methodologies of co-operative co-evolution and operational specialization. The standard approach to neural-evolution is at the network level such that a population of working solutions is manipulated until the fittest member is found. SANE [Symbiotic Adaptive Neuro-Evolution]1 source code offers an alternative method based on co-operative co-evolution in which a population of hidden neurons is evolved. The task of each hidden neuron is to establish appropriate connections that will provide: [i] a functional solution and [ii] performance improvements. Each member of the population attempts to optimize one particular aspect of the overall modelling process and evolution can lead to several different forms of specialization. This method of adaptive evolution also facilitates the creation of symbiotic relationships in which individual members must co-operate with others - who must be present - to permit survival. 1http://www.cs.utexas.edu/users/nn/pages/software/abstracts.html#sane-c

Abrahart, R. J.

2004-05-01

148

Hydrologic Modeling of a Bioinfiltration Best Management Practice  

NASA Astrophysics Data System (ADS)

The goal of this research was to develop a methodology for modeling a bioinfiltration best management practice (BMP) built in a dormitory area on the campus of Villanova University in Pennsylvania. The objectives were to quantify the behavior of the BMP through the different seasons and rainfall events; better understand the physical processes governing the system's behavior; and develop design criteria. The BMP was constructed in 2001 by excavating within an existing traffic island, backfilling with a sand/soil mixture, and planting with salt tolerant grasses and shrubs native to the Atlantic shore. It receives runoff from the asphalt (0.26 hectare) and turf (0.27 hectare) surfaces of the watershed. Monitoring supported by the hydrologic model shows that the facility infiltrates a significant fraction of the annual precipitation, substantially reducing the delivery of nonpoint source pollution and erosive surges downstream. A hydrologic model was developed using HECHMS to represent the site and the BMP using Green-Ampt and kinematic wave methods. Instruments allow comparison of the modeled and measured water budget parameters. The model, incorporating seasonally variable parameters, predicts the volumes infiltrated and bypassed by the BMP, confirming the applicability of the selected methods for the analysis of bioinfiltration BMPs.

Heasom, William; Traver, Robert G.; Welker, Andrea

2006-10-01

149

Mid-Holocene hydrologic model of the Shingobee watershed, Minnesota  

USGS Publications Warehouse

A hydrologifc model of the Shingobee Watershed in north-central Minnesota was developed to reconstruct mid-Holocene paleo-lake levels for Williams Lake, a surface-water body located in the southern portion of the watershed. Hydrologic parameters for the model were first estimated in a calibration exercise using a 9-yr historical record (1990-1998) of climatic and hydrologic stresses. The model reproduced observed temporal and spatial trends in surface/groundwater levels across the watershed. Mid-Holocene aquifer and lake levels were then reconstructed using two paleoclimatic data sets: CCM1 atmospheric general circulation model output and pollen-transfer functions using sediment core data from Williams Lake. Calculated paleo-lake levels based on pollen-derived paleoclimatic reconstructions indicated a 3.5-m drop in simulated lake levels and were in good agreement with the position of mid-Holocene beach sands observed in a Williams Lake sediment core transect. However, calculated paleolake levels based on CCM1 climate forcing produced only a 0.05-m drop in lake levels. We found that decreases in winter precipitation rather than temperature increases had the largest effect on simulated mid-Holocene lake levels. The study illustrates how watershed models can be used to critically evaluate paleoclimatic reconstructions by integrating geologic, climatic, limnologic, and hydrogeologic data sets. ?? 2002 University of Washington.

Filby, S.K.; Locke, S.M.; Person, M.A.; Winter, T.C.; Rosenberry, D.O.; Nieber, J.L.; Gutowski, W.J.; Ito, E.

2002-01-01

150

Climate change impact on available water resources obtained using multiple global climate and hydrology models  

NASA Astrophysics Data System (ADS)

Climate change is expected to alter the hydrological cycle resulting in large-scale impacts on water availability. However, future climate change impact assessments are highly uncertain. For the first time, multiple global climate (three) and hydrological models (eight) were used to systematically assess the hydrological response to climate change and project the future state of global water resources. This multi-model ensemble allows us to investigate how the hydrology models contribute to the uncertainty in projected hydrological changes compared to the climate models. Due to their systematic biases, GCM outputs cannot be used directly in hydrological impact studies, so a statistical bias correction has been applied. The results show a large spread in projected changes in water resources within the climate-hydrology modelling chain for some regions. They clearly demonstrate that climate models are not the only source of uncertainty for hydrological change, and that the spread resulting from the choice of the hydrology model is larger than the spread originating from the climate models over many areas. But there are also areas showing a robust change signal, such as at high latitudes and in some midlatitude regions, where the models agree on the sign of projected hydrological changes, indicative of higher confidence in this ensemble mean signal. In many catchments an increase of available water resources is expected but there are some severe decreases in Central and Southern Europe, the Middle East, the Mississippi River basin, southern Africa, southern China and south-eastern Australia.

Hagemann, S.; Chen, C.; Clark, D. B.; Folwell, S.; Gosling, S. N.; Haddeland, I.; Hanasaki, N.; Heinke, J.; Ludwig, F.; Voss, F.; Wiltshire, A. J.

2013-05-01

151

A one-parameter Budyko model for water balance captures emergent behavior in darwinian hydrologic models  

NASA Astrophysics Data System (ADS)

models can be categorized as being either Newtonian or Darwinian in nature. The Newtonian approach requires a thorough understanding of the individual physical processes acting in a watershed in order to build a detailed hydrologic model based on the conservation equations. The Darwinian approach seeks to explain the behavior of a hydrologic system as a whole by identifying simple and robust temporal or spatial patterns that capture the relevant processes. Darwinian-based hydrologic models include the Soil Conservation Service (SCS) curve number model, the "abcd" model, and the Budyko-type models. However, these models were developed based on widely differing principles and assumptions and applied to distinct time scales. Here, we derive a one-parameter Budyko-type model for mean annual water balance which is based on a generalization of the proportionality hypothesis of the SCS model and therefore is independent of temporal scale. Furthermore, we show that the new model is equivalent to the key equation of the "abcd" model. Theoretical lower and upper bounds of the new model are identified and validated based on previous observations. Thus, we illustrate a temporal pattern of water balance amongst Darwinian hydrologic models, which allows for synthesis with the Newtonian approach and offers opportunities for progress in hydrologic modeling.

Wang, Dingbao; Tang, Yin

2014-07-01

152

Assessing model state and forecasts variation in hydrologic data assimilation  

NASA Astrophysics Data System (ADS)

Data assimilation (DA) has been widely used in hydrological models to improve model state and subsequent streamflow estimates. However, for poor or non-existent state observations, the state estimation in hydrological DA can be problematic, leading to inaccurate streamflow updates. This study evaluates the soil moisture and flow variations and forecasts by assimilating streamflow and soil moisture. Three approaches of Ensemble Kalman Filter (EnKF) with dual state-parameter estimation are applied: (1) streamflow assimilation, (2) soil moistue assimilation, and (3) combined assimilation of soil moisture and streamflow. The assimilation approaches are evaluated using the Sacramento Soil Moisture Accounting (SAC-SMA) model in the Spencer Creek catchment in southern Ontario, Canada. The results show that there are significant differences in soil moisture variations and streamflow estimates when the three assimilation approaches were applied. In the streamflow assimilation, soil moisture states were markedly distorted, particularly soil moisture of lower soil layer; whereas, in the soil moisture assimilation, streamflow estimates are inaccurate. The combined assimilation of streamflow and soil moisture provides more accurate forecasts of both soil moisture and streamflow, particularly for shorter lead times. The combined approach has the flexibility to account for model adjustment through the time variation of parameters together with state variables when soil moisture and streamflow observations are integrated into the assimilation procedure. This evaluation is important for the application of DA methods to simultaneously estimate soil moisture states and watershed response and forecasts.

Samuel, Jos; Coulibaly, Paulin; Dumedah, Gift; Moradkhani, Hamid

2014-05-01

153

Evaluating Hydrological Model Outputs with Satellite derived Land Surface Temperature  

NASA Astrophysics Data System (ADS)

A combined investigation of the water and energy balance in hydrologic models is needed for a better understanding of exchange, transport, and feedback processes in the soil-vegetation-atmosphere system. These models, however, are often only evaluated at gauging stations. While this evaluation does not provide any information about the spatial distribution of hydrological variables, such as evapotranspiration and soil moisture, additional methods have to be found. The objective of this study is to indirectly evaluate such variables using satellite derived Land Surface Temperature (LST) fields. Therefore, we calculate the Land Surface Temperature with the hydrological model mHM from the sensible heat formulation. The sensible heat is determined as residual of the energy balance, assuming that the soil heat flux and the storage term is negligible at the daily time scale. Additionally, the evapotranspiration is determined due to solving the water balance with mHM. Furthermore, the remaining term of the energy balance, the net radiation, is obtained by solving the radiation budget using long and shortwave incoming radiation, albedo and emissivity data from the Land Surface Analysis - Satellite Application Facility (LSA-SAF, landsaf.meteo.pt). Finally, to determine the LST, the aerodynamic resistance is parameterized to solve the sensible heat formulation. The calculated fields of land surface temperature are evaluated against those provided by LSA-SAF for a period from 2005-2010. The study is carried out in Germany, whereas sets of good performing global transfer parameters are estimated in seven German river basins: Danube, Ems, Main, Mulde, Neckar, Saale and Weser. The average Nash Sutcliffe Efficiencies exceeds 0.7 in the validation period from 2005 to 2010. Preliminary results indicate that the estimated mHM LST agrees quite well with the satellite observations. This result indirectly indicates that the simulated evapotranspiration and corresponding soil moisture fields are reasonable estimates. This assertion will be corroborated by comparison with hourly evapotranspiration fluxes obtained at nine eddy covariance measurement stations (www.fluxdata.org).

Zink, M.; Samaniego, L.; Cuntz, M.; Kumar, R.

2012-04-01

154

A hydrological model of New Zealand - version 2  

NASA Astrophysics Data System (ADS)

We report recent progress on a long-term hydrological modelling project whose goal is to make reliable estimates of all water fluxes and storages of New Zealand, and reliable estimates of potential changes in those water resources. This is an ambitious scientific project, with many practical implications for water use and water planning. The model assumes a single model structure (TopNet, see Clark et al 2008), and uses a priori parameter estimation, based on national datasets, without calibration. The model uses an hourly timestep and was run for 40 years. New Zealand's 260,000 sq km area is subdivided into 35,000 subcatchments of about 7 sq km each. Experience with practical applications of a priori parameter estimation have shown that the two parameters of TopNet which lead to the greatest source of uncertainty in river flows are TOPMODF and HYDCON0. These describe the rate of change of saturated soil hydraulic conductivity with depth, and the saturated soil hydraulic conductivity at the ground surface, respectively. We will show results for selected regions and river basins, and assess the model performance against measured soil moisture and snow storage, as well as measured streamflow. As well as being useful as regional and national models, the results provide a sound start for model calibration, if needed. There are opportunities to improve on these results through improved mapping of recession characteristics, improved use of recording raingauge data, and selection of model structure to match the spatial variations in hydrological processes which are not captured by a fixed model structure. This model underpins new regional and national forecasts and climate change assessments which are now in development.

Woods, Ross; Zammit, Christian; Singh, Shailesh; McMillan, Hilary; Henderson, Roddy

2013-04-01

155

Hydrological Ensemble Simulation in Huaihe Catchment Based on VIC Model  

NASA Astrophysics Data System (ADS)

Huaihe catchment plays a very important role in the political, economic, and cultural development in China. However, hydrological disasters frequently occur in Huaihe catchment, and thus hydrological simulation in this area has very important significance. The Variable Infiltration Capacity(VIC)model, a macroscale distributed hydrological model is applied to the upper Huaihe Catchment, to simulate the discharge of the basin outlet Bengbu station from 1970 to 1999. The uncertainty in the calibration of VIC model parameters has been analyzed, and the best set of parameters in the training period of 1970~1993 is achieved using the Generalized Likelihood Uncertainty Estimation (GLUE) method. The study also addresses the influence of different likelihood functions for the parameter sensitivity as well as the uncertainty of discharge simulation. Results show that among the six chosen parameters, the soil thickness of the second layer (d2) is the most sensitive one, followed by the saturation capacity curve shape parameter (B). Moreover, the parameter selection is sensitive to different likelihood functions. For example, the soil thickness of the third layer (d3) is sensitive when using Nash coefficient as the likelihood function, while d3 is not sensitive when using relative error as the likelihood function. With the 95% confidence interval, the coverage rate of the simulated discharge versus the observed discharge is small (around 0.4), indicating that the uncertainty in the model is large. The coverage rate of selecting relative error as the likelihood function is bigger than that of selecting Nash coefficient. Based on the calibration and sensitivity studies, hydrological ensemble forecasts have been established using multiple parameter sets. The ensemble mean forecasts show better simulations than the control forecast (i.e. the simulation using the best set of parameters) for the long-term trend of discharge, while the control forecast is better in the simulation of peak value. Probabilistic streamflow forecasts are also evaluated in the simulation of extreme peak flow. In addition, the influence of different training periods for the parameter sensitivity is discussed. Parameter scatter diagrams Discharge of Bengbu station

Sun, R.; Yuan, H.

2013-12-01

156

Hidden Markov model segmentation of hydrological and enviromental time series  

E-print Network

Motivated by Hubert's segmentation procedure we discuss the application of hidden Markov models (HMM) to the segmentation of hydrological and enviromental time series. We use a HMM algorithm which segments time series of several hundred terms in a few seconds and is computationally feasible for even longer time series. The segmentation algorithm computes the Maximum Likelihood segmentation by use of an expectation / maximization iteration. We rigorously prove algorithm convergence and use numerical experiments, involving temperature and river discharge time series, to show that the algorithm usually converges to the globally optimal segmentation. The relation of the proposed algorithm to Hubert's segmentation procedure is also discussed.

Ath. Kehagias

2002-06-25

157

Validating a spatially distributed hydrological model with soil morphology data  

NASA Astrophysics Data System (ADS)

Spatially distributed models are popular tools in hydrology claimed to be useful to support management decisions. Despite the high spatial resolution of the computed variables, calibration and validation is often carried out only on discharge time series at specific locations due to the lack of spatially distributed reference data. Because of this restriction, the predictive power of these models, with regard to predicted spatial patterns, can usually not be judged. An example of spatial predictions in hydrology is the prediction of saturated areas in agricultural catchments. These areas can be important source areas for inputs of agrochemicals to the stream. We set up a spatially distributed model to predict saturated areas in a 1.2 km2 catchment in Switzerland with moderate topography and artificial drainage. We translated soil morphological data available from soil maps into an estimate of the duration of soil saturation in the soil horizons. This resulted in a data set with high spatial coverage on which the model predictions were validated. In general, these saturation estimates corresponded well to the measured groundwater levels. We worked with a model that would be applicable for management decisions because of its fast calculation speed and rather low data requirements. We simultaneously calibrated the model to observed groundwater levels and discharge. The model was able to reproduce the general hydrological behavior of the catchment in terms of discharge and absolute groundwater levels. However, the the groundwater level predictions were not accurate enough to be used for the prediction of saturated areas. Groundwater level dynamics were not adequately reproduced and the predicted spatial saturation patterns did not correspond to those estimated from the soil map. Our results indicate that an accurate prediction of the groundwater level dynamics of the shallow groundwater in our catchment that is subject to artificial drainage would require a model that better represents processes at the boundary between the unsaturated and the saturated zone. However, data needed for such a more detailed model are not generally available. This severely hampers the practical use of such models despite their usefulness for scientific purposes.

Doppler, T.; Honti, M.; Zihlmann, U.; Weisskopf, P.; Stamm, C.

2014-09-01

158

Long-term Regional Drought Forecasting by Combining Seasonal Weather Outlook, Hydrological Model and System Dynamic Model  

NASA Astrophysics Data System (ADS)

This study integrated the rainfall-runoff model, seasonal weather outlook, and VENSIM system dynamic model to construct a long-term regional drought forecasting system. Central Taiwan contains several river basins. The water supplies and demands in these river basins compose several water resources systems in the region. To develop a long-term regional drought forecasting system for this region, the simulations of interaction among the water resources systems are required. The future inflows of reservoir for each individual water resources system are forecasted based on the seasonal (3 months ahead) weather outlook and the rainfall-runoff model. Then, the future water usage (trade-off between water demand and supply) of all water resources systems can be simulated by using the VENSIM system dynamic model. Therefore, the long-term regional drought can be forecasted based on the future water usage. The seasonal weather outlook provided by the Central Weather Bureau of Taiwan is the trend probabilities of the monthly rainfall and monthly mean temperature for the three months ahead. By using the re-sampling approach, the trend probabilities for the future three months are converted to daily series as the input of rainfall-runoff model. The inflows of reservoir for each water resources system are simulated by the rainfall-runoff model (i.e., the HBV-based hydrological model) with corresponding calibrated model parameters. Then, the study can simulate the daily inflow series in the next 3 months. Since the study area contains several water resources systems, the VENSIM system dynamic model is used to simulate the trade-off between water supply and demand on the whole region. In the system dynamic model, the interactions among the available water, demand of each location and the adjustable water for neighbor system are simulated. Based on the simulations of VENSIM system dynamic model, the study can forecast the deficit amounts and the locations of possible drought in the next 3 months. Combining the rainfall-runoff model, long-term weather outlook, and VENSIM system dynamic model with user friendly interfaces, the proposed regional drought forecast system will be very useful for the policy making when the area faces a possible drought in the future three months.

Kuo, C.; Wang, Y.; Yang, T.; Yu, P.

2012-12-01

159

Integrating water resources management in eco-hydrological modelling.  

PubMed

In this paper the integration of water resources management with regard to reservoir management in an eco-hydrological model is described. The model was designed to simulate different reservoir management options, such as optimized hydropower production, irrigation intake from the reservoir or optimized provisioning downstream. The integrated model can be used to investigate the impacts of climate variability/change on discharge or to study possible adaptation strategies in terms of reservoir management. The study area, the Upper Niger Basin located in the West African Sahel, is characterized by a monsoon-type climate. Rainfall and discharge regime are subject to strong seasonality. Measured data from a reservoir are used to show that the reservoir model and the integrated management options can be used to simulate the regulation of this reservoir. The inflow into the reservoir and the discharge downstream of the reservoir are quite distinctive, which points out the importance of the inclusion of water resources management. PMID:23552241

Koch, H; Liersch, S; Hattermann, F F

2013-01-01

160

Disaggregation, aggregation and spatial scaling in hydrological modelling  

NASA Astrophysics Data System (ADS)

A typical feature of the land surface is its heterogeneity in terms of the spatial variability of land surface characteristics and parameters controlling physical/hydrological, biological, and other related processes. Different forms and degrees of heterogeneity need to be taken into account in hydrological modelling. The first part of the article concerns the conditions under which a disaggregation of the land surface into subareas of uniform or "quasihomogeneous" behaviour (hydrotopes or hydrological response units - HRUs) is indispensable. In a case study in northern Germany, it is shown that forests in contrast to arable land, areas with shallow groundwater in contrast to those with deep, water surfaces and sealed areas should generally be distinguished (disaggregated) in modelling, whereas internal heterogeneities within these hydrotopes can be assessed statistically, e.g., by areal distribution functions (soil water holding capacity, hydraulic conductivity, etc.). Models with hydrotope-specific parameters can be applied to calculate the "vertical" processes (fluxes, storages, etc.), and this, moreover, for hydrotopes of different area, and even for groups of distributed hydrotopes in a reference area (hydrotope classes), provided that the meteorological conditions are similar. Thus, a scaling problem does not really exist in this process domain. The primary domain for the application of scaling laws is that of lateral flows in landscapes and river basins. This is illustrated in the second part of the article, where results of a case study in Bavaria/Germany are presented and discussed. It is shown that scaling laws can be applied efficiently for the determination of the Instantaneous Unit Hydrograph (IUH) of the surface runoff system in river basins: simple scaling for basins larger than 43 km 2, and multiple scaling for smaller basins. Surprisingly, only two parameters were identified as important in the derived relations: the drainage area and, in some cases, the elevation a.s.l.. The scaling exponent was determined as equal or approximately equal to the exponent 0.566 in Hack's law. Therefore, it is suggested that there is some relation between the scaling laws and the fractal nature of river networks, and accordingly with the complex dynamics of the interacting hydrological and geomorphological processes in river basins.

Becker, Alfred; Braun, Peter

1999-04-01

161

One-Water Hydrologic Flow Model (MODFLOW-OWHM)  

USGS Publications Warehouse

The One-Water Hydrologic Flow Model (MF-OWHM) is a MODFLOW-based integrated hydrologic flow model (IHM) that is the most complete version, to date, of the MODFLOW family of hydrologic simulators needed for the analysis of a broad range of conjunctive-use issues. Conjunctive use is the combined use of groundwater and surface water. MF-OWHM allows the simulation, analysis, and management of nearly all components of human and natural water movement and use in a physically-based supply-and-demand framework. MF-OWHM is based on the Farm Process for MODFLOW-2005 (MF-FMP2) combined with Local Grid Refinement (LGR) for embedded models to allow use of the Farm Process (FMP) and Streamflow Routing (SFR) within embedded grids. MF-OWHM also includes new features such as the Surface-water Routing Process (SWR), Seawater Intrusion (SWI), and Riparian Evapotrasnpiration (RIP-ET), and new solvers such as Newton-Raphson (NWT) and nonlinear preconditioned conjugate gradient (PCGN). This IHM also includes new connectivities to expand the linkages for deformation-, flow-, and head-dependent flows. Deformation-dependent flows are simulated through the optional linkage to simulated land subsidence with a vertically deforming mesh. Flow-dependent flows now include linkages between the new SWR with SFR and FMP, as well as connectivity with embedded models for SFR and FMP through LGR. Head-dependent flows now include a modified Hydrologic Flow Barrier Package (HFB) that allows optional transient HFB capabilities, and the flow between any two layers that are adjacent along a depositional or erosional boundary or displaced along a fault. MF-OWHM represents a complete operational hydrologic model that fully links the movement and use of groundwater, surface water, and imported water for consumption by irrigated agriculture, but also of water used in urban areas and by natural vegetation. Supply and demand components of water use are analyzed under demand-driven and supply-constrained conditions. From large- to small-scale settings, MF-OWHM has the unique set of capabilities to simulate and analyze historical, present, and future conjunctive-use conditions. MF-OWHM is especially useful for the analysis of agricultural water use where few data are available for pumpage, land use, or agricultural information. The features presented in this IHM include additional linkages with SFR, SWR, Drain-Return (DRT), Multi-Node Wells (MNW1 and MNW2), and Unsaturated-Zone Flow (UZF). Thus, MF-OWHM helps to reduce the loss of water during simulation of the hydrosphere and helps to account for “all of the water everywhere and all of the time.” In addition to groundwater, surface-water, and landscape budgets, MF-OWHM provides more options for observations of land subsidence, hydraulic properties, and evapotranspiration (ET) than previous models. Detailed landscape budgets combined with output of estimates of actual evapotranspiration facilitates linkage to remotely sensed observations as input or as additional observations for parameter estimation or water-use analysis. The features of FMP have been extended to allow for temporally variable water-accounting units (farms) that can be linked to land-use models and the specification of both surface-water and groundwater allotments to facilitate sustainability analysis and connectivity to the Groundwater Management Process (GWM). An example model described in this report demonstrates the application of MF-OWHM with the addition of land subsidence and a vertically deforming mesh, delayed recharge through an unsaturated zone, rejected infiltration in a riparian area, changes in demand caused by deficiency in supply, and changes in multi-aquifer pumpage caused by constraints imposed through the Farm Process and the MNW2 Package, and changes in surface water such as runoff, streamflow, and canal flows through SFR and SWR linkages.

Hanson, Randall T.; Boyce, Scott E.; Schmid, Wolfgang; Hughes, Joseph D.; Mehl, Steffen W.; Leake, Stanley A.; Maddock, Thomas, III; Niswonger, Richard G.

2014-01-01

162

EFFICIENT HYDROLOGICAL TRACER-TEST DESIGN (EHTD) MODEL  

EPA Science Inventory

Hydrological tracer testing is the most reliable diagnostic technique available for establishing flow trajectories and hydrologic connections and for determining basic hydraulic and geometric parameters necessary for establishing operative solute-transport processes. Tracer-test...

163

Spatiotemporal variability of hydrologic response : an entropy-based approach using a distributed hydrologic model  

E-print Network

Basin hydrologic response pertains to the partitioning of precipitation into stream-flow, evapotranspiration, and change in storage. The ability to explain or predict the response has many applications e.g. flood forecasting, ...

Castillo, Aldrich Edra

2014-01-01

164

An energetic perspective on hydrological cycle changes in the Geoengineering Model Intercomparison Project  

E-print Network

An energetic perspective on hydrological cycle changes in the Geoengineering Model Intercomparison-ocean general circulation models simulating experiment G1 of the Geoengineering Model Intercomparison Project perspective on hydrological cycle changes in the Geoengineering Model Intercomparison Project, J. Geophys. Res

Robock, Alan

165

Quantifying and generalizing hydrologic responses to dam regulation using a statistical modeling approach  

NASA Astrophysics Data System (ADS)

Despite the ubiquitous existence of dams within riverscapes, much of our knowledge about dams and their environmental effects remains context-specific. Hydrology, more than any other environmental variable, has been studied in great detail with regard to dam regulation. While much progress has been made in generalizing the hydrologic effects of regulation by large dams, many aspects of hydrology show site-specific fidelity to dam operations, small dams (including diversions), and regional hydrologic regimes. A statistical modeling framework is presented as a predictive tool to quantify and generalize hydrologic responses to varying degrees of dam regulation at large spatial scales. In addition, the approach provides a method to expand sample sizes beyond that of traditional dam-hydrologic-effect analyses. Model performance was relatively poor with models explaining 10-31% of the variation in hydrologic responses. However, models had relatively high accuracies (61-89%) in classifying the direction of hydrologic responses as negative or positive. Responses of many hydrologic indices to dam regulation were highly dependent upon regional hydrology, the purpose of the dam, and the presence of diversion dams. In addition, models revealed opposite effects of dam regulation in systems regulated by individual dams versus many upstream dams, suggesting that the effects of dams may be countered by other dams in basins experiencing intensified cumulative disturbance. Results also suggested that particular contexts, including multipurpose dams, high cumulative regulation, diversions, and regions of unpredictable hydrology are all sources of increased error when predicting hydrologic responses to dams. Statistical models, such as the ones presented herein, show promise in their ability to generalize the directionality of hydrologic responses to dam regulation and provide parameter coefficients to inform future site-specific modeling efforts.

McManamay, Ryan A.

2014-11-01

166

Real Time Land-Surface Hydrologic Modeling Over Continental US  

NASA Technical Reports Server (NTRS)

The land surface component of the hydrological cycle is fundamental to the overall functioning of the atmospheric and climate processes. Spatially and temporally variable rainfall and available energy, combined with land surface heterogeneity cause complex variations in all processes related to surface hydrology. The characterization of the spatial and temporal variability of water and energy cycles are critical to improve our understanding of land surface-atmosphere interaction and the impact of land surface processes on climate extremes. Because the accurate knowledge of these processes and their variability is important for climate predictions, most Numerical Weather Prediction (NWP) centers have incorporated land surface schemes in their models. However, errors in the NWP forcing accumulate in the surface and energy stores, leading to incorrect surface water and energy partitioning and related processes. This has motivated the NWP to impose ad hoc corrections to the land surface states to prevent this drift. A proposed methodology is to develop Land Data Assimilation schemes (LDAS), which are uncoupled models forced with observations, and not affected by NWP forcing biases. The proposed research is being implemented as a real time operation using an existing Surface Vegetation Atmosphere Transfer Scheme (SVATS) model at a 40 km degree resolution across the United States to evaluate these critical science questions. The model will be forced with real time output from numerical prediction models, satellite data, and radar precipitation measurements. Model parameters will be derived from the existing GIS vegetation and soil coverages. The model results will be aggregated to various scales to assess water and energy balances and these will be validated with various in-situ observations.

Houser, Paul R.

1998-01-01

167

Development of an Open Source GIS based Distributed Hydrological model System - MWEasyDHM  

NASA Astrophysics Data System (ADS)

Spatially distributed hydrological model is an important tool for studying the hydrological cycle, making flood forecasting, simulating environmental and ecological processes and estimating crop water demand and so on. Successful distributed hydrological model and systems have been further achieved in many developed countries. However, there needs one GIS based Distributed Hydrological Model system to carry out hydrological simulation suitable for current conditions of China. In this paper a distributed hydrological model system for easy manipulation, MWEasyDHM (MapWindow based Distributed Hydrological Model), was developed based on MapWindow GIS platform, an open source GIS software. The system contains pretreatment, model parameters optimization and posttreatment modules to simplify the works of building distributed hydrological model. The pretreatment module includes hydrological analysis, model parameters estimation and weather data interpolation parts based on huge amount of spatial and temporal data sets such as weather, land use, soil type, etc. With the pretreatment results, distributed hydrological model could be calculated and optimal model parameters could be obtained with LH-OAT parameters sensitivity analysis and SCE-UA parameters optimization. After model simulation, the model results could be displayed with tables, charts and GIS forms, in addition, spatial and temporal statistics and analysis could be easily achieved with the postreatment. Finally, a brief application of MWEasyDHM will be described to demonstrate the flexibilities and capacities of the model system. With the successful development of MWEasyDHM, the processes of model building, calibration and application could be much easier and distributed hydrological model could be easily applied to the areas of water resources management.

Lei, Xiaohui; Wang, Yuhui; Jiang, Yunzhong; Wang, Hao; Tian, Yu; Liao, Weihong

2010-05-01

168

ANNIE - INTERACTIVE PROCESSING OF DATA BASES FOR HYDROLOGIC MODELS.  

USGS Publications Warehouse

ANNIE is a data storage and retrieval system that was developed to reduce the time and effort required to calibrate, verify, and apply watershed models that continuously simulate water quantity and quality. Watershed models have three categories of input: parameters to describe segments of a drainage area, linkage of the segments, and time-series data. Additional goals for ANNIE include the development of software that is easily implemented on minicomputers and some microcomputers and software that has no special requirements for interactive display terminals. Another goal is for the user interaction to be based on the experience of the user so that ANNIE is helpful to the inexperienced user and yet efficient and brief for the experienced user. Finally, the code should be designed so that additional hydrologic models can easily be added to ANNIE.

Lumb, Alan M.; Kittle, John L.

1985-01-01

169

Advances in Modeling of Coupled Hydrologic-Socioeconomic Systems  

NASA Astrophysics Data System (ADS)

River flooding is the most common natural disaster in Europe, causing deaths and huge amount of economic losses. Disastrous flood events are often related to extreme meteorological conditions; therefore, climate change is expected to have an important influence over the intensity and frequency of major floods. While approximated large-scale assessments of flood risk scenarios have been carried out, the knowledge of the effects at smaller scales is poor or incomplete, with few localized studies. Also, the methods are still coarse and uneven. The approach of this study starts from the definition of the risk paradigm and the elaboration of local climatic scenarios to track a methodology aimed at elaborating and combining the three elements concurring to the determination of risk: hydrological hazard, value exposure and vulnerability. First, hydrological hazard scenarios are provided by hydrological and hydrodynamic models, used in to a flood forecasting system capable to define "what-if" scenario in a flexible way. These results are then integrated with land-use data (exposure) and depth-damage functions (vulnerability) in a GIS environment, to assess the final risk value (potential flood damage) and visualize it in form of risk maps. In this paper results from a pilot study in the Polesine area are presented, where four simulated levee breach scenarios are compared. The outcomes of the analysis may be instrumental to authorities to increase the knowledge of possible direct losses and guide decision making and planning processes also. As future perspective, the employed methodology can also be extended at the basin scale through integration with the existent flood warning system to gain a real-time estimate of floods direct costs.

Amadio, Mattia; Mysiak, Jaroslav; Pecora, Silvano; Agnetti, Alberto

2013-04-01

170

Modeling Soil Depth Based Upon Topographic and Land Cover Attributes to Improve Models of Hydrological Response  

NASA Astrophysics Data System (ADS)

Soil depth is an important input parameter in hydrological modeling. Presently, the soil depth data available in national soil databases (STATSGO, SSURGO) is provided as averages within generalized map units. Spatial uncertainty within these units limits their applicability for distributed hydrological modeling in complex terrain. Statistical models were developed for prediction of soil depth in a semiarid mountainous watershed based upon topographic and land cover attributes. Soil depth was surveyed by driving a rod into the ground until refusal at 819 calibration and 130 independent testing locations selected to represent the topographic and land cover variation in Dry Creek Experimental Watershed, Boise, Idaho. Topographic attributes derived from a Digital Elevation Model (DEM) and Land cover attributes derived from remote sensing were used in Generalized Additive and Random Forest models to predict soil depth over the watershed. The models were able to explain about 50% of the soil depth spatial variation with a significant part of this capability due to new DEM derived topographic variables. The soil depths obtained from these models are being used as input to a spatially distributed hydrological model to evaluate the sensitivity of hydrological response and potential for improvement in hydrological model estimates due to better soil depth information.

Tesfa, T. K.; Tarboton, D. G.; Chandler, D. G.; McNamara, J. P.

2008-12-01

171

Hydrological Modelling in the Lake Tana Basin, Ethiopia Using SWAT Model  

Microsoft Academic Search

The SWAT2005 model was applied to the Lake Tana Basin for modeling of the hydrological water balance. The main objective of this study was to test the performance and feasibility of the SWAT model for prediction of stream- flow in the Lake Tana Basin. The model was calibrated and validated on four tributaries of Lake Tana; Gumera, GilgelA- bay, Megech

Shimelis G. Setegn; Ragahavan Srinivasan; Bijan Dargahi

2008-01-01

172

Data-based mechanistic modelling of hydrological systems  

NASA Astrophysics Data System (ADS)

Data-based Mechanistic (DBM) modelling is an inductive approach to model identification and estimation in which the parsimonious model structure and associated parameter estimates are inferred directly from the available time series data with a minimum of a priori assumptions about the model form. It differs from "black-box" modelling because the resulting model is only considered acceptable if it can be interpreted in a physically meaningful manner. This paper will consider DBM modelling in the context of characterizing hydrology process dynamics at the catchment scale and, in particular, the transfer function modelling of nonlinear rainfall-flow processes for the purpose of flow and flood forecasting. Transfer function models of rainfall-flow processes have a number of advantages when applied in the context of flood forecasting. They are simple; capable of physical interpretation when estimated in a DBM manner; and, most importantly in the context of this Special Session, inherently stochastic in form, so allowing for the quantification of the uncertainty associated with physically meaningful parameters and multi-step-ahead forecasts. The paper will report on recent results relating to the identification and estimation of both discrete and continuous-time, nonlinear transfer function models from rainfall-flow data. It will also address a number of other topics including the selection of appropriate estimation methods.

Young, P. C.

2003-04-01

173

Integration of the variable infiltration capacity model soil hydrology scheme into the community land model  

NASA Astrophysics Data System (ADS)

Enhancements to the soil hydrology scheme in the NCAR Community Land Model version 3 (CLM3) are described, which are intended to improve the ability of CLM to represent land surface hydrologic processes. Specifically, the CLM3 soil hydrology scheme has been replaced with the scheme used in the Variable Infiltration Capacity model (VIC). While the modified model incorporates VIC soil hydrology, the original model structure in CLM3 is unchanged in most other respects, such as the representation of vegetation and its controls on surface energy exchanges. The modified version of CLM3 makes direct use of VIC soil parameters that have been developed for off-line regional, continental, and global simulations. The performance of the new model and CLM3 are evaluated through a comparison with observations at three flux tower sites: ABRACOS, a pasture clearing in the Brazilian rain forest, HAPEX-MOBILHY, a midlatitude agricultural site in France, and Valdai, a midlatitude grassland in Russia, as well as two large river basins (Arkansas-Red and Colorado in the United States). Overall, the results show that the merged model better reproduces observed soil hydrological variability, in particular, the seasonal evolution and amplitude of soil moisture, as compared to CLM3. The river basin simulations show that in the merged model, total runoff is generally less than in CLM3 and better agrees with observations. Owing to the interaction of runoff and soil moisture, the simulation of total evapotranspiration (or latent heat) is also improved in the merged model.

Wang, Aihui; Li, Kaiyuan Y.; Lettenmaier, Dennis P.

2008-05-01

174

Hydrological modelling of slopes from field monitoring data  

NASA Astrophysics Data System (ADS)

A simplified hydrological model of a steep slope covered with loose granular pyroclastic deposits is presented. The slope is located in the mountains northern of Naples, and the soil cover, constituted by layers of loose volcanic ashes and pumices with a total thickness of 2.5m, lays upon a fractured limestone bedrock. At the interface between the bedrock and the soil cover, a layer of weathered ashes, with significant clay fraction, is sometimes observed. The slope has a fairly regular inclination of 40°, and is covered by chestnut woods and thick brushwood growing in late spring. The inclination of the slope is comparable with the internal friction angle of the ashes, thus the equilibrium is possible thanks to the contribution offered to the shear strength by the soil suction in unsaturated conditions. Indeed, in December 1999, a landslide was triggered by prolonged and intense precipitations. As it frequently happens with similar pyroclastic covers, the triggered slide exhibited a flow-like behavior, covering 2km in few minutes, heavily hitting the nearby town of Cervinara (AV). Since then, the slope has been constantly monitored, and during the last two years an automated station with seven TDR probes for the measurement of soil water content, eight tensiometers for the measurement of soil suction, and a rain gauge, has been operating. The data, collected every two hours, allowed getting more insight of the hydrological behavior of the slope and building up an effective hydrological model. In the model, the layered soil profile has been replaced with a single homogeneous layer, with water retention curve estimated by coupling the values of water content and suction measured at various depths. A seasonal top boundary condition has been introduced, related to the annual cycle of the vegetation: the observed precipitations quickly caused changes of soil suction at the depth of -50cm during the entire year, with the exception of the period between the end of May and the early August. To reproduce the observed behavior of soil suction at the bottom of the profile, a linear reservoir model has been introduced as bottom boundary condition, related to the presence of a small aquifer in the fractured bedrock, which water table, affecting the hydraulic conditions of the soil cover, rapidly deepens during the dry season. The developed model, calibrated with the data of one year of observation, satisfactorily reproduces the observed soil hydraulic behaviour also during other periods.

Comegna, Luca; Damiano, Emilia; Greco, Roberto; Guida, Andrea; Olivares, Lucio; Picarelli, Luciano

2013-04-01

175

The application of remote sensing to the development and formulation of hydrologic planning models  

NASA Technical Reports Server (NTRS)

A hydrologic planning model is developed based on remotely sensed inputs. Data from LANDSAT 1 are used to supply the model's quantitative parameters and coefficients. The use of LANDSAT data as information input to all categories of hydrologic models requiring quantitative surface parameters for their effects functioning is also investigated.

Castruccio, P. A.; Loats, H. L., Jr.; Fowler, T. R.

1976-01-01

176

Improved Ground Hydrology Calculations for Global Climate Models (GCMs): Soil Water Movement and Evapotranspiration  

Microsoft Academic Search

A physically based ground hydrology model is developed to improve the land-surface sensible and latent heat calculations in global climate models (GCMs). The processes of transpiration, evaporation from intercepted precipitation and dew, evaporation from bare soil, infiltration, soil water flow, and runoff are explicitly included in the model. The amount of detail in the hydrologic calculations is restricted to a

F. Abramopoulos; C. Rosenzweig; B. Choudhury

1988-01-01

177

Hydrological excitation of polar motion by different variables of the GLDAS models  

NASA Astrophysics Data System (ADS)

Continental hydrological loading, by land water, snow, and ice, is an element that is strongly needed for a full understanding of the excitation of polar motion. In this study we compute different estimations of hydrological excitation functions of polar motion (Hydrological Angular Momentum - HAM) using various variables from the Global Land Data Assimilation System (GLDAS) models of land hydrosphere. The main aim of this study is to show the influence of different variables for example: total evapotranspiration, runoff, snowmelt, soil moisture to polar motion excitations in annual and short term scale. In our consideration we employ several realizations of the GLDAS model as: GLDAS Common Land Model (CLM), GLDAS Mosaic Model, GLDAS National Centers for Environmental Prediction/Oregon State University/Air Force/Hydrologic Research Lab Model (Noah), GLDAS Variable Infiltration Capacity (VIC) Model. Hydrological excitation functions of polar motion, both global and regional, are determined by using selected variables of these GLDAS realizations. First we compare a timing, spectra and phase diagrams of different regional and global HAMs with each other. Next, we estimate, the hydrological signal in geodetically observed polar motion excitation by subtracting the atmospheric -- AAM (pressure + wind) and oceanic -- OAM (bottom pressure + currents) contributions. Finally, the hydrological excitations are compared to these hydrological signal in observed polar motion excitation series. The results help us understand which variables of considered hydrological models are the most important for the polar motion excitation and how well we can close polar motion excitation budget in the seasonal and inter-annual spectral ranges.

Wi?ska, Ma?gorzata; Nastula, Jolanta

178

Testing calibration routines for LISFLOOD, a distributed hydrological model  

NASA Astrophysics Data System (ADS)

Traditionally hydrological models are considered as difficult to calibrate: their highly non-linearity results in rugged and rough response surfaces were calibration algorithms easily get stuck in local minima. For the calibration of distributed hydrological models two extra factors play an important role: on the one hand they are often costly on computation, thus restricting the feasible number of model runs; on the other hand their distributed nature smooths the response surface, thus facilitating the search for a global minimum. Lisflood is a distributed hydrological model currently used for the European Flood Alert System - EFAS (Van der Knijff et al, 2008). Its upcoming recalibration over more then 200 catchments, each with an average runtime of 2-3 minutes, proved a perfect occasion to put several existing calibration algorithms to the test. The tested routines are Downhill Simplex (DHS, Nelder and Mead, 1965), SCEUA (Duan et Al. 1993), SCEM (Vrugt et al., 2003) and AMALGAM (Vrugt et al., 2008), and they were evaluated on their capability to efficiently converge onto the global minimum and on the spread in the found solutions in repeated runs. The routines were let loose on a simple hyperbolic function, on a Lisflood catchment using model output as observation, and on two Lisflood catchments using real observations (one on the river Inn in the Alps, the other along the downstream stretch of the Elbe). On the mathematical problem and on the catchment with synthetic observations DHS proved to be the fastest and the most efficient in finding a solution. SCEUA and AMALGAM are a slower, but while SCEUA keeps converging on the exact solution, AMALGAM slows down after about 600 runs. For the Lisflood models with real-time observations AMALGAM (hybrid algorithm that combines several other algorithms, we used CMA, PSO and GA) came as fastest out of the tests, and giving comparable results in consecutive runs. However, some more work is needed to tweak the stopping criteria. SCEUA is a bit slower, but has very transparent stopping rules. Both have closed in on the minima after about 600 runs. DHS equals only SCEUA on convergence speed. The stopping criteria we applied so far are too strict, causing it to stop too early. SCEM converges 5-6 times slower. This is a high price for the parameter uncertainty analysis that is simultaneously done. The ease with which all algorithms find the same optimum suggests that we are dealing with a smooth and relatively simple response surface. This leaves room for other deterministic calibration algorithms being smarter than DHS in sliding downhill. PEST seems promising but sofar we haven't managed to get it running with LISFLOOD. • Duan, Q.; Gupta, V. & Sorooshian, S., 1993, Shuffled complex evolution approach for effective and efficient global minimization, J Optim Theory Appl, Kluwer Academic Publishers-Plenum Publishers, 76, 501-521 • Nelder, J. & Mead, R., 1965, A simplex method for function minimization, Comput. J., 7, 308-313 • Van Der Knijff, J. M.; Younis, J. & De Roo, A. P. J., 2008, LISFLOOD: a GIS-based distributed model for river basin scale water balance and flood simulation, International Journal of Geographical Information Science, • Vrugt, J.; Gupta, H.; Bouten, W. & Sorooshian, S., 2003, A Shuffled Complex Evolution Metropolis algorithm for optimization and uncertainty assessment of hydrologic model parameters, Water Resour. Res., 39 • Vrugt, J.; Robinson, B. & Hyman, J., 2008, Self-Adaptive Multimethod Search for Global Optimization in Real-Parameter Spaces, IEEE Trans Evol Comput, IEEE,

Pannemans, B.

2009-04-01

179

GIS embedded hydrological modeling: the SID&GRID project  

NASA Astrophysics Data System (ADS)

The SID&GRID research project, started April 2010 and funded by Regione Toscana (Italy) under the POR FSE 2007-2013, aims to develop a Decision Support System (DSS) for water resource management and planning based on open source and public domain solutions. In order to quantitatively assess water availability in space and time and to support the planning decision processes, the SID&GRID solution consists of hydrological models (coupling 3D existing and newly developed surface- and ground-water and unsaturated zone modeling codes) embedded in a GIS interface, applications and library, where all the input and output data are managed by means of DataBase Management System (DBMS). A graphical user interface (GUI) to manage, analyze and run the SID&GRID hydrological models based on open source gvSIG GIS framework (Asociación gvSIG, 2011) and a Spatial Data Infrastructure to share and interoperate with distributed geographical data is being developed. Such a GUI is thought as a "master control panel" able to guide the user from pre-processing spatial and temporal data, running the hydrological models, and analyzing the outputs. To achieve the above-mentioned goals, the following codes have been selected and are being integrated: 1. Postgresql/PostGIS (PostGIS, 2011) for the Geo Data base Management System; 2. gvSIG with Sextante (Olaya, 2011) geo-algorithm library capabilities and Grass tools (GRASS Development Team, 2011) for the desktop GIS; 3. Geoserver and Geonetwork to share and discover spatial data on the web according to Open Geospatial Consortium; 4. new tools based on the Sextante GeoAlgorithm framework; 5. MODFLOW-2005 (Harbaugh, 2005) groundwater modeling code; 6. MODFLOW-LGR (Mehl and Hill 2005) for local grid refinement; 7. VSF (Thoms et al., 2006) for the variable saturated flow component; 8. new developed routines for overland flow; 9. new algorithms in Jython integrated in gvSIG to compute the net rainfall rate reaching the soil surface, as input for the unsaturated/saturated flow model. At this stage of the research (which will end April 2013), two primary components of the master control panel are being developed: i. a SID&GRID toolbar integrated into gvSIG map context; ii. a new Sextante set of geo-algorithm to pre- and post-process the spatial data to run the hydrological models. The groundwater part of the code has been fully integrated and tested and 3D visualization tools are being developed. The LGR capability has been extended to the 3D solution of the Richards' equation in order to solve in detail the unsaturated zone where required. To be updated about the project, please follow us at the website: http://ut11.isti.cnr.it/SIDGRID/

Borsi, I.; Rossetto, R.; Schifani, C.

2012-04-01

180

Parameterization of potential evapotranspiration approaches for distributed hydrologic modeling  

NASA Astrophysics Data System (ADS)

Reliable soil moisture products are needed for the estimation of plant available water or agricultural droughts. For the simulation of hydrological states, e.g. soil moisture, the estimation of evapotranspiration is crucial since it has the largest contribution to the water balance besides precipitation. In hydrological modeling the evapotranspiration is usually estimated based on potential evapotranspiration (PET). The common approaches for PET estimation and their parameterization are sufficient at the point or field scale for which they have been developed. But for spatially distributed estimations on the mesoscale, e.g. 4 km, their robust parameterization is still a challenge in current research. The aim of this study is to find scale and location independent parameters for three different potential evapotranspiration formulations, which are applied in the mesoscale Hydrologic Model (mHM). PET is estimated using the 1) Hargreaves-Samani, 2) Priestley-Taylor, and 3) Penman-Monteith equations. The Hargreaves-Samani method is a temperature driven approach, whereas the other two methods are based on radiation. For estimating the parameters of the above mentioned PET formulations, the Multiscale Parameter Regionalization technique is used. This technique accounts for subgrid variabilities by connecting morphological terrain properties, which are available in a higher resolution than the model resolution, with the parameters for the particular PET approach. The parameters, which needed to be estimated, are the coefficient of the Hargreaves-Samani equation, the Priestley-Taylor coefficient, and the aerodynamic and bulk surface resistance for the Penman-Monteith equation. The Hargreaves-Samani coefficient is regionalized based on the aspect of the terrain. The Priestley-Taylor coefficient as well as the aerodynamic and bulk surface resistance have been estimated using static land cover information combined with leaf area index (LAI) development curves and thus an approximation for vegetation information. This new parameterized PET approaches are evaluated in six different German river basins ranging from 6,000 km2 to 38,000 km2 including a spatial variety from catchments in the northern German lowlands to alpine catchments in the south. The comparison of the results is focusing on evapotranspiration, soil moisture and discharge. Whereas only slight changes in the discharge hydrograph have been observed in the comparison of the three PET equations, the impact on soil moisture is significant. Especially during the summer period the soil moisture is lower for the Priestley-Taylor and Penman-Monteith formulation compared to the Hargreaves-Samani equation. This effect is due to higher estimates in PET for those two methods. Furthermore a validation against eddy covariance measurements showed that the dynamics of evapotranspiration is captured well by the three methods.

Zink, Matthias; Mai, Juliane; Cuntz, Matthias; Samaniego, Luis

2014-05-01

181

Hydrologic Modeling of the White Sands Dune Field, New Mexico  

NASA Astrophysics Data System (ADS)

The shallow groundwater flow system of White Sands dune field, located within the Tularosa Basin of Southern New Mexico, likely stabilizes the base of the largest gypsum dunefield in the world. Water table geometry and elevation play a critical role in controlling dune thickness, spatial extent, and migration rates. The White Sands National Monument (WHSA) is concerned that lowering the water table may lead to increased scour and migration of the dune field, which could be unfavorable to the preservation of the flora and fauna that have adapted to survive there. In response to projected increases in groundwater pumping in the regional Tularosa Basin groundwater system, changes in surface water use, and the threat of climate change, the WHSA is interested in understanding how these changes on a regional scale may impact the shallow dune aquifer. We have collected hydrological, geochemical, and geophysical data in order to identify the sources of recharge that contribute to the shallow dune aquifer and to assess interactions between this water table aquifer and the basin-scale, regional system. Vertical head gradients, temperature, and water quality data strongly suggest that local precipitation is the primary source of recharge to the dune aquifer today. This suggests that the modern dune system is relatively isolated from the deeper regional system. However, geochemical and electrical resistivity data indicates that the deeper basin groundwater system does contribute to the shallow system and suggests that hydrologic conditions have changed on geologic time scales. We have constructed a preliminary cross-sectional hydrologic model to attempt to characterize the interaction of the shallow dune aquifer with the deeper basin groundwater. The model cross-section extends about 80 km across the Tularosa Basin in a NW-SE direction parallel to the primary flow path. We represented 6 km of Precambrian crystalline basement, Paleozoic sedimentary rocks as well as Pleistocene and Quaternary units. Preliminary results indicate a component of deep groundwater flows to a depth of 5 km and is discharged near Lake Lucero located west of the WHSA. Computed and observed salinity and groundwater residence times are the primary means of model calibration. The results will allow for an improved understanding of the interaction between the basin- and dune-scale groundwater flow systems.

Bourret, S. M.; Newton, B. T.; Person, M. A.

2013-12-01

182

A simple hydrologically based model of land surface water and energy fluxes for general circulation models  

Microsoft Academic Search

A generalization of the single soil layer variable infiltration capacity (VIC) land surface hydrological model previously implemented in the Geophysical Fluid Dynamics Laboratory (GFDL) general circulation model (GCM) is described. The new model is comprised of a two-layer characterization of the soil column, and uses an aerodynamic representation of the latent and sensible heat fluxes at the land surface. The

Xu Liang; Dennis P. Lettenmaier; S. J. Burges

1994-01-01

183

Multiobjective sensitivity analysis and optimization of distributed hydrologic model MOBIDIC  

NASA Astrophysics Data System (ADS)

Calibration of distributed hydrologic models usually involves how to deal with the large number of distributed parameters and optimization problems with multiple but often conflicting objectives that arise in a natural fashion. This study presents a multiobjective sensitivity and optimization approach to handle these problems for the MOBIDIC (MOdello di Bilancio Idrologico DIstribuito e Continuo) distributed hydrologic model, which combines two sensitivity analysis techniques (the Morris method and the state-dependent parameter (SDP) method) with multiobjective optimization (MOO) approach ?-NSGAII (Non-dominated Sorting Genetic Algorithm-II). This approach was implemented to calibrate MOBIDIC with its application to the Davidson watershed, North Carolina, with three objective functions, i.e., the standardized root mean square error (SRMSE) of logarithmic transformed discharge, the water balance index, and the mean absolute error of the logarithmic transformed flow duration curve, and its results were compared with those of a single objective optimization (SOO) with the traditional Nelder-Mead simplex algorithm used in MOBIDIC by taking the objective function as the Euclidean norm of these three objectives. Results show that (1) the two sensitivity analysis techniques are effective and efficient for determining the sensitive processes and insensitive parameters: surface runoff and evaporation are very sensitive processes to all three objective functions, while groundwater recession and soil hydraulic conductivity are not sensitive and were excluded in the optimization. (2) Both MOO and SOO lead to acceptable simulations; e.g., for MOO, the average Nash-Sutcliffe value is 0.75 in the calibration period and 0.70 in the validation period. (3) Evaporation and surface runoff show similar importance for watershed water balance, while the contribution of baseflow can be ignored. (4) Compared to SOO, which was dependent on the initial starting location, MOO provides more insight into parameter sensitivity and the conflicting characteristics of these objective functions. Multiobjective sensitivity analysis and optimization provide an alternative way for future MOBIDIC modeling.

Yang, J.; Castelli, F.; Chen, Y.

2014-10-01

184

Operational hydrological ensemble forecasts in France. Recent development of the French Hydropower Company (EDF), taking into account rainfall and hydrological model uncertainties.  

NASA Astrophysics Data System (ADS)

In operational conditions, the actual quality of meteorological and hydrological forecasts do not allow decision-making in a certain future. In this context, meteorological and hydrological ensemble forecasts allow a better representation of forecasts uncertainties. Compared to classical deterministic forecasts, ensemble forecasts improve the human expertise of hydrological forecasts, which is essential to synthesize available informations, coming from different meteorological and hydrological models and human experience. In this paper, we present a hydrological ensemble forecasting system under development at EDF (French Hydropower Company). This forecasting system both takes into account rainfall forecasts uncertainties and hydrological model forecasts uncertainties. Hydrological forecasts were generated using the MORDOR model (Andreassian et al., 2006), developed at EDF and used on a daily basis in operational conditions on a hundred of watersheds. Two sources of rainfall forecasts were used : one is based on ECMWF forecasts, another is based on an analogues approach (Obled et al., 2002). Two methods of hydrological model forecasts uncertainty estimation were used : one is based on the use of equifinal parameter sets (Beven & Binley, 1992), the other is based on the statistical modelisation of the hydrological forecast empirical uncertainty (Montanari et al., 2004 ; Schaefli et al., 2007). Daily operational hydrological 7-day ensemble forecasts during 2 years in 3 alpine watersheds were evaluated. Finally, we present a way to combine rainfall and hydrological model forecast uncertainties to achieve a good probabilistic calibration. Our results show that the combination of ECMWF and analogues-based rainfall forecasts allow a good probabilistic calibration of rainfall forecasts. They show also that the statistical modeling of the hydrological forecast empirical uncertainty has a better probabilistic calibration, than the equifinal parameter set approach. Andreassian et al., 2006. Catalogue of the models used in MOPEX 2004/2005. Large sample basin experiments for hydrological mode parameterisation : results of the Model Parameter Experiment, IAHS Publ. 307, 41-94. Beven & Binley, 1992. The future of distributed models : model calibration and uncertainty prediction. Hydrological Processes, 6, 279-298. Obled, C., Bontron, G., Garçon, R., 2002. Quantitative precipitation forecasts: a statistical adaptation of model outputs though an analogues sorting approach. Atmospheric Research, 63, 303-324. Montanari, A. and Brath, A., 2004. A stochastic approach for assessing the uncertainty of rainfall-runoff simulations. Water Resources Research, 40, W01106, doi:10.1029/2003WR002540. Schaefli, B., Balin Talamba, D. and Musy, A., 2007. Quantifying hydrological modeling errors through a mixture of normal distributions. Journal of Hydrology, 332, 303-315.

Mathevet, T.; Garavaglia, F.; Garçon, R.; Gailhard, J.; Paquet, E.

2009-04-01

185

Multi-model ensemble hydrologic prediction and uncertainties analysis  

NASA Astrophysics Data System (ADS)

Modelling uncertainties (i.e. input errors, parameter uncertainties and model structural errors) inevitably exist in hydrological prediction. A lot of recent attention has focused on these, of which input error modelling, parameter optimization and multi-model ensemble strategies are the three most popular methods to demonstrate the impacts of modelling uncertainties. In this paper the Xinanjiang model, the Hybrid rainfall-runoff model and the HYMOD model were applied to the Mishui Basin, south China, for daily streamflow ensemble simulation and uncertainty analysis. The three models were first calibrated by two parameter optimization algorithms, namely, the Shuffled Complex Evolution method (SCE-UA) and the Shuffled Complex Evolution Metropolis method (SCEM-UA); next, the input uncertainty was accounted for by introducing a normally-distributed error multiplier; then, the simulation sets calculated from the three models were combined by Bayesian model averaging (BMA). The results show that both these parameter optimization algorithms generate good streamflow simulations; specifically the SCEM-UA can imply parameter uncertainty and give the posterior distribution of the parameters. Considering the precipitation input uncertainty, the streamflow simulation precision does not improve very much. While the BMA combination not only improves the streamflow prediction precision, it also gives quantitative uncertainty bounds for the simulation sets. The SCEM-UA calculated prediction interval is better than the SCE-UA calculated one. These results suggest that considering the model parameters' uncertainties and doing multi-model ensemble simulations are very practical for streamflow prediction and flood forecasting, from which more precision prediction and more reliable uncertainty bounds can be generated.

Jiang, S.; Ren, L.; Yang, X.; Ma, M.; Liu, Y.

2014-09-01

186

Feedback Loop of Data Infilling Using Model Result of Actual Evapotranspiration from Satellites and Hydrological Model  

NASA Astrophysics Data System (ADS)

Using satellite data in a hydrological model has long been occurring in modelling of hydrological processes, as a source of low cost regular data. The methods range from using satellite products as direct input, model validation, and data assimilation. However, the satellite data frequently face the missing value problem, whether due to the cloud cover or the limited temporal coverage. The problem could seriously affect its usefulness in hydrological model, especially if the model uses it as direct input, so data infilling becomes one of the important parts in the whole modelling exercise. In this research, actual evapotranspiration product from satellite is directly used as input into a spatially distributed hydrological model, and validated by comparing the catchment's end discharge with measured data. The instantaneous actual evapotranspiration is estimated from MODIS satellite images using a variation of the energy balance model for land (SEBAL). The eight-day cumulative actual evapotranspiration is then obtained by a temporal integration that uses the reference evapotranspiration calculated from meteorological data [1]. However, the above method cannot fill in a cell if the cell is constantly having no-data value during the eight-day periods. The hydrological model requires full set of data without no-data cells, hence, the no-data cells in the satellite's evapotranspiration map need to be filled in. In order to fills the no-data cells, an output of hydrological model is used. The hydrological model is firstly run with reference evapotranspiration as input to calculate discharge and actual evapotranspiration. The no-data cells in the eight-day cumulative map from the satellite are then filled in with the output of the first run of hydrological model. The final data is then used as input in a hydrological model to calculate discharge, thus creating a loop. The method is applied in the case study of Rijnland, the Netherlands where in the winter, cloud cover is persistent and leads to many no-data cells in the satellite products. The Rijnland area is a low-lying area with tight water system control. The satellite data is used as input in a SIMGRO model, a spatially distributed hydrological model that is able to handle the controlled water system and that is suitable for the low-lying areas in the Netherlands. The application in the Rijnland area gives overall a good result of total discharge. By using the method, the hydrological model is improved in term of spatial hydrological state, where the original model is only calibrated to discharge in one location. [1] Alexandridis, T.K., Cherif, I., Chemin, Y., Silleos, G.N., Stavrinos, E. & Zalidis, G.C. (2009). Integrated Methodology for Estimating Water Use in Mediterranean Agricultural Areas. Remote Sensing. 1

Murdi Hartanto, Isnaeni; Alexandridis, Thomas K.; van Andel, Schalk Jan; Solomatine, Dimitri

2014-05-01

187

Calibration of hydrological models using flow-duration curves  

NASA Astrophysics Data System (ADS)

The degree of belief we have in predictions from hydrologic models will normally depend on how well they can reproduce observations. Calibrations with traditional performance measures, such as the Nash-Sutcliffe model efficiency, are challenged by problems including: (1) uncertain discharge data, (2) variable sensitivity of different performance measures to different flow magnitudes, (3) influence of unknown input/output errors and (4) inability to evaluate model performance when observation time periods for discharge and model input data do not overlap. This paper explores a calibration method using flow-duration curves (FDCs) to address these problems. The method focuses on reproducing the observed discharge frequency distribution rather than the exact hydrograph. It consists of applying limits of acceptability for selected evaluation points (EPs) on the observed uncertain FDC in the extended GLUE approach. Two ways of selecting the EPs were tested - based on equal intervals of discharge and of volume of water. The method was tested and compared to a calibration using the traditional model efficiency for the daily four-parameter WASMOD model in the Paso La Ceiba catchment in Honduras and for Dynamic TOPMODEL evaluated at an hourly time scale for the Brue catchment in Great Britain. The volume method of selecting EPs gave the best results in both catchments with better calibrated slow flow, recession and evaporation than the other criteria. Observed and simulated time series of uncertain discharges agreed better for this method both in calibration and prediction in both catchments. An advantage with the method is that the rejection criterion is based on an estimation of the uncertainty in discharge data and that the EPs of the FDC can be chosen to reflect the aims of the modelling application, e.g. using more/less EPs at high/low flows. While the method appears less sensitive to epistemic input/output errors than previous use of limits of acceptability applied directly to the time series of discharge, it still requires a reasonable representation of the distribution of inputs. Additional constraints might therefore be required in catchments subject to snow and where peak-flow timing at sub-daily time scales is of high importance. The results suggest that the calibration method can be useful when observation time periods for discharge and model input data do not overlap. The method could also be suitable for calibration to regional FDCs while taking uncertainties in the hydrological model and data into account.

Westerberg, I. K.; Guerrero, J.-L.; Younger, P. M.; Beven, K. J.; Seibert, J.; Halldin, S.; Freer, J. E.; Xu, C.-Y.

2011-07-01

188

Calibration of hydrological models using flow-duration curves  

NASA Astrophysics Data System (ADS)

The degree of belief we have in predictions from hydrologic models depends on how well they can reproduce observations. Calibrations with traditional performance measures such as the Nash-Sutcliffe model efficiency are challenged by problems including: (1) uncertain discharge data, (2) variable importance of the performance with flow magnitudes, (3) influence of unknown input/output errors and (4) inability to evaluate model performance when observation time periods for discharge and model input data do not overlap. A new calibration method using flow-duration curves (FDCs) was developed which addresses these problems. The method focuses on reproducing the observed discharge frequency distribution rather than the exact hydrograph. It consists of applying limits of acceptability for selected evaluation points (EPs) of the observed uncertain FDC in the extended GLUE approach. Two ways of selecting the EPs were tested - based on equal intervals of discharge and of volume of water. The method was tested and compared to a calibration using the traditional model efficiency for the daily four-parameter WASMOD model in the Paso La Ceiba catchment in Honduras and for Dynamic TOPMODEL evaluated at an hourly time scale for the Brue catchment in Great Britain. The volume method of selecting EPs gave the best results in both catchments with better calibrated slow flow, recession and evaporation than the other criteria. Observed and simulated time series of uncertain discharges agreed better for this method both in calibration and prediction in both catchments without resulting in overpredicted simulated uncertainty. An advantage with the method is that the rejection criterion is based on an estimation of the uncertainty in discharge data and that the EPs of the FDC can be chosen to reflect the aims of the modelling application e.g. using more/less EPs at high/low flows. While the new method is less sensitive to epistemic input/output errors than the normal use of limits of acceptability applied directly to the time series of discharge, it still requires a reasonable representation of the distribution of inputs. Additional constraints might therefore be required in catchments subject to snow. The results suggest that the new calibration method can be useful when observation time periods for discharge and model input data do not overlap. The new method could also be suitable for calibration to regional FDCs while taking uncertainties in the hydrological model and data into account.

Westerberg, I. K.; Guerrero, J.-L.; Younger, P. M.; Beven, K. J.; Seibert, J.; Halldin, S.; Freer, J. E.; Xu, C.-Y.

2010-12-01

189

Visualization in hydrological and atmospheric modeling and observation  

NASA Astrophysics Data System (ADS)

In recent years, visualization of geoscientific and climate data has become increasingly important due to challenges such as climate change, flood prediction or the development of water management schemes for arid and semi-arid regions. Models for simulations based on such data often have a large number of heterogeneous input data sets, ranging from remote sensing data and geometric information (such as GPS data) to sensor data from specific observations sites. Data integration using such information is not straightforward and a large number of potential problems may occur due to artifacts, inconsistencies between data sets or errors based on incorrectly calibrated or stained measurement devices. Algorithms to automatically detect various of such problems are often numerically expensive or difficult to parameterize. In contrast, combined visualization of various data sets is often a surprisingly efficient means for an expert to detect artifacts or inconsistencies as well as to discuss properties of the data. Therefore, the development of general visualization strategies for atmospheric or hydrological data will often support researchers during assessment and preprocessing of the data for model setup. When investigating specific phenomena, visualization is vital for assessing the progress of the ongoing simulation during runtime as well as evaluating the plausibility of the results. We propose a number of such strategies based on established visualization methods that - are applicable to a large range of different types of data sets, - are computationally inexpensive to allow application for time-dependent data - can be easily parameterized based on the specific focus of the research. Examples include the highlighting of certain aspects of complex data sets using, for example, an application-dependent parameterization of glyphs, iso-surfaces or streamlines. In addition, we employ basic rendering techniques allowing affine transformations, changes in opacity as well as variation of transfer functions. We found that similar strategies can be applied for hydrological and atmospheric data such as the use of streamlines for visualization of wind or fluid flow or iso-surfaces as indicators of groundwater recharge levels in the subsurface or levels of humidity in the atmosphere. We applied these strategies for a wide range of hydrological and climate applications such as groundwater flow, distribution of chemicals in water bodies, development of convection cells in the atmosphere or heat flux on the earth's surface. Results have been evaluated in discussions with experts from hydrogeology and meteorology.

Helbig, C.; Rink, K.; Kolditz, O.

2013-12-01

190

Parameterising hydrological models - Comparing optimisation and robust parameter estimation  

NASA Astrophysics Data System (ADS)

SummaryIn most conditions, calibration is a prerequisite for successfully applying conceptual and physically based rainfall-runoff models. The goal of this paper is to comparatively analyse the potential of both event-based automatic calibration (PEST) as described in Skahill and Doherty (2006) and robust parameter estimation (ROPE) as proposed by Bárdossy and Singh (2008). The results of our modelling study in the Rietholzbach catchment (Switzerland) show that ROPE performs better in validation of small to medium sized events. This indicates that ROPE might be better suited to parameterise models when the modellers intention is focussed on a maximising the generalisation capacity of the model, e.g. for evaluating transient process characteristics. We base our study on the hydrological model WaSiM-ETH, using a combined ROPE and automatic parameter estimation approach to investigate optimal parameter sets. The PEST algorithm used in this study outperforms the ROPE application by a factor of roughly 100 in terms of time required for computation.

Cullmann, Johannes; Krausse, Thomas; Saile, Phillip

2011-07-01

191

An eco-hydrologic model of malaria outbreaks  

NASA Astrophysics Data System (ADS)

Malaria is a geographically widespread infectious disease that is well known to be affected by climate variability at both seasonal and interannual timescales. In an effort to identify climatic factors that impact malaria dynamics, there has been considerable research focused on the development of appropriate disease models for malaria transmission and their consideration alongside climatic datasets. These analyses have focused largely on variation in temperature and rainfall as direct climatic drivers of malaria dynamics. Here, we further these efforts by considering additionally the role that soil water content may play in driving malaria incidence. Specifically, we hypothesize that hydro-climatic variability should be an important factor in controlling the availability of mosquito habitats, thereby governing mosquito growth rates. To test this hypothesis, we reduce a nonlinear eco-hydrologic model to a simple linear model through a series of consecutive assumptions and apply this model to malaria incidence data from three South African provinces. Despite the assumptions made in the reduction of the model, we show that soil water content can account for a significant portion of malaria's case variability beyond its seasonal patterns, whereas neither temperature nor rainfall alone can do so. Future work should therefore consider soil water content as a simple and computable variable for incorporation into climate-driven disease models of malaria and other vector-borne infectious diseases.

Montosi, E.; Manzoni, S.; Porporato, A.; Montanari, A.

2012-03-01

192

A coupled energy transport and hydrological model for urban canopies  

NASA Astrophysics Data System (ADS)

Urban land-atmosphere interaction has been attracting more research efforts in order to understand the complex physics of flow and mass and heat transport in urban surfaces and the lower urban atmosphere. In this work, we developed and implemented a new physically-based single-layer urban canopy model, coupling the surface exchange of energy and the subsurface transport of water/soil moisture. The new model incorporates sub-facet heterogeneity for each urban surface (roof, wall or ground). This better simulates the energy transport in urban canopy layers, especially over low-intensity built (suburban type) terrains that include a significant fraction of vegetated surfaces. We implemented detailed urban hydrological models for both natural terrains (bare soil and vegetation) and porous engineered materials with water-holding capacity (concrete, gravel, etc). The skill of the new scheme was tested against experimental data collected through a wireless sensor network deployed over the campus of Princeton University. The model performance was found to be robust and insensitive to changes in weather conditions or seasonal variability. Predictions of the volumetric soil water content were also in good agreement with field measurements, highlighting the model capability of capturing subsurface water transport for urban lawns. The new model was also applied to a case study assessing different strategies, i.e. white versus green roofs, in the mitigation of urban heat island effect.

Wang, Z.; Bou-Zeid, E.; Smith, J. A.

2011-12-01

193

Dynamic Neural Networks for Nonstationary Hydrological Time Series Modeling  

Microsoft Academic Search

Evidence of nonstationary trends in hydrological time series, which result from natural and\\/or anthropogenic climatic variability\\u000a and change, has raised a number of questions as to the adequacy of conventional statistical methods for long-term (seasonal\\u000a to annual) hydrologic time series forecasting. Most conventional statistical methods that are used in hydrology will suffer\\u000a from severe limitations as they assume a stationary

P. Coulibaly; C. K. Baldwin

194

Stimulation from Simulation? A Teaching Model of Hillslope Hydrology for Use on Microcomputers.  

ERIC Educational Resources Information Center

The design and use of a simple computer model which simulates a hillslope hydrology is described in a teaching context. The model shows a relatively complex environmental system can be constructed on the basis of a simple but realistic theory, thus allowing students to simulate the hydrological response of real hillslopes. (Author/TRS)

Burt, Tim; Butcher, Dave

1986-01-01

195

Simulated Climatology of a General Circulation Model with a Hydrologic CYCLE1  

Microsoft Academic Search

A numerical experiment with a general circulation model with a simple hydrologic cycle is performed. The basic framework of this model is identical with that adopted for the previous study (35) except for the incorporation of a simplified hydrologic cycle which consists of the advection of water vapor by large-scale motion, evaporation from t.he surface, precipitation, and an artificial adjustment

Syukuro Manabe; Joseph Smagorinsky; Robert F. Strickler

1965-01-01

196

Hydrologic modeling of two glaciated watersheds in Northeast Pennsylvania  

USGS Publications Warehouse

A hydrologic modeling study, using the Hydrologic Simulation Program - FORTRAN (HSPF), was conducted in two glaciated watersheds, Purdy Creek and Ariel Creek in northeastern Pennsylvania. Both watersheds have wetlands and poorly drained soils due to low hydraulic conductivity and presence of fragipans. The HSPF model was calibrated in the Purdy Creek watershed and verified in the Ariel Creek watershed for June 1992 to December 1993 period. In Purdy Creek, the total volume of observed streamflow during the entire simulation period was 13.36 x 106 m3 and the simulated streamflow volume was 13.82 x 106 m3 (5 percent difference). For the verification simulation in Ariel Creek, the difference between the total observed and simulated flow volumes was 17 percent. Simulated peak flow discharges were within two hours of the observed for 30 of 46 peak flow events (discharge greater than 0.1 m3/sec) in Purdy Creek and 27 of 53 events in Ariel Creek. For 22 of the 46 events in Purdy Creek and 24 of 53 in Ariel Creek, the differences between the observed and simulated peak discharge rates were less than 30 percent. These 22 events accounted for 63 percent of total volume of streamflow observed during the selected 46 peak flow events in Purdy Creek. In Ariel Creek, these 24 peak flow events accounted for 62 percent of the total flow observed during all peak flow events. Differences in observed and simulated peak flow rates and volumes (on a percent basis) were greater during the snowmelt runoff events and summer periods than for other times.A hydrologic modeling study, using the Hydrologic Simulation Program - FORTRAN (HSPF), was conducted in two glaciated watersheds, Purdy Creek and Ariel Creek in northeastern Pennsylvania. Both watersheds have wetlands and poorly drained soils due to low hydraulic conductivity and presence of fragipans. The HSPF model was calibrated in the Purdy Creek watershed and verified in the Ariel Creek watershed for June 1992 to December 1993 period. In Purdy Creek, the total volume of observed streamflow during the entire simulation period was 13.36??106 m3 and the simulated streamflow volume was 13.82??106 m3 (5 percent difference). For the verification simulation in Ariel Creek, the difference between the total observed and simulated flow volumes was 17 percent. Simulated peak flow discharges were within two hours of the observed for 30 of 46 peak flow events (discharge greater than 0.1 m3/sec) in Purdy Creek and 27 of 53 events in Ariel Creek. For 22 of the 46 events in Purdy Creek and 24 of 53 in Ariel Creek, the differences between the observed and simulated peak discharge rates were less than 30 percent. These 22 events accounted for 63 percent of total volume of streamflow observed during the selected 46 peak flow events in Purdy Creek. In Ariel Creek, these 24 peak flow events accounted for 62 percent of the total flow observed during all peak flow events. Differences in observed and simulated peak flow rates and volumes (on a percent basis) were greater during the snowmelt runoff events and summer periods than for other times.

Srinivasan, M.S.; Hamlett, J.M.; Day, R.L.; Sams, J.I.; Petersen, G.W.

1998-01-01

197

Integrating an open source dynamic river model in hydrology modeling frameworks  

NASA Astrophysics Data System (ADS)

A challenge for hydrology modeling is linking landscape runoff models with river network models. Although some hydrological models directly implement a river routing scheme within their code, such a monolithic approach is too rigid because it does not allow the latest river routing advances to be used. Unlike the 2D interface between atmospheric and landscape models, the interface between landscape runoff models and river network models is more difficult to define. In this PICO presentation, we address problems with model interfaces, which are related to issues such as time and space-scale differences between the models. We also provide an overview of SPRINT, an open source river network model, which has adapted the model interface architecture and numerical methods widely used in semiconductor microchip design. Finally, we propose two model integration mechanisms: the file-based "net-list" and the API (application programming interface) approach.

Liu, Frank; Hodges, Ben

2014-05-01

198

A METHODOLOGY FOR ESTIMATING UNCERTAINTY OF A DISTRIBUTED HYDROLOGIC MODEL: APPLICATION TO POCONO CREEK WATERSHED  

EPA Science Inventory

Utility of distributed hydrologic and water quality models for watershed management and sustainability studies should be accompanied by rigorous model uncertainty analysis. However, the use of complex watershed models primarily follows the traditional {calibrate/validate/predict}...

199

Hydrologic Setting and Conceptual Hydrologic Model of the Walker River Basin, West-Central Nevada  

USGS Publications Warehouse

The Walker River is the main source of inflow to Walker Lake, a closed-basin lake in west-central Nevada. Between 1882 and 2008, agricultural diversions resulted in a lake-level decline of more than 150 feet and storage loss of 7,400,000 acre-ft. Evaporative concentration increased dissolved solids from 2,500 to 17,000 milligrams per liter. The increase in salinity threatens the survival of the Lahontan cutthroat trout, a native species listed as threatened under the Endangered Species Act. This report describes the hydrologic setting of the Walker River basin and a conceptual hydrologic model of the relations among streams, groundwater, and Walker Lake with emphasis on the lower Walker River basin from Wabuska to Hawthorne, Nevada. The Walker River basin is about 3,950 square miles and straddles the California-Nevada border. Most streamflow originates as snowmelt in the Sierra Nevada. Spring runoff from the Sierra Nevada typically reaches its peak during late May to early June with as much as 2,800 cubic feet per second in the Walker River near Wabuska. Typically, 3 to 4 consecutive years of below average streamflow are followed by 1 or 2 years of average or above average streamflow. Mountain ranges are comprised of consolidated rocks with low hydraulic conductivities, but consolidated rocks transmit water where fractured. Unconsolidated sediments include fluvial deposits along the active channel of the Walker River, valley floors, alluvial slopes, and a playa. Sand and gravel deposited by the Walker River likely are discontinuous strata throughout the valley floor. Thick clay strata likely were deposited in Pleistocene Lake Lahontan and are horizontally continuous, except where strata have been eroded by the Walker River. At Walker Lake, sediments mostly are clay interbedded with alluvial slope, fluvial, and deltaic deposits along the lake margins. Coarse sediments form a multilayered, confined-aquifer system that could extend several miles from the shoreline. Depth to bedrock in the lower Walker River basin ranges from about 900 to 2,000 feet. The average hydraulic conductivity of the alluvial aquifer in the lower Walker River basin is 10-30 feet per day, except where comprised of fluvial sediments. Fluvial sediments along the Walker River have an average hydraulic conductivity of 70 feet per day. Subsurface flow was estimated to be 2,700 acre-feet per year through Double Spring. Subsurface discharge to Walker Lake was estimated to be 4,400 acre-feet per year from the south and 10,400 acre-feet per year from the north. Groundwater levels and groundwater storage have declined steadily in most of Smith and Mason Valleys since 1960. Groundwater levels around Schurz, Nevada, have changed little during the past 50 years. In the Whisky Flat area south of Hawthorne, Nevada, agricultural and municipal pumpage has lowered groundwater levels since 1956. The water-level decline in Walker Lake since 1882 has caused the surrounding alluvial aquifer to drain and groundwater levels to decline. The Wabuska streamflow-gaging station in northern Mason Valley demarcates the upper and lower Walker River basin. The hydrology of the lower Walker River basin is considerably different than the upper basin. The upper basin consists of valleys separated by consolidated-rock mountains. The alluvial aquifer in each valley thins or pinches out at the downstream end, forcing most groundwater to discharge along the river near where the river is gaged. The lower Walker River basin is one surface-water/groundwater system of losing and gaining reaches from Wabuska to Walker Lake, which makes determining stream losses and the direction and amount of subsurface flow difficult. Isotopic data indicate surface water and groundwater in the lower Walker River basin are from two sources of precipitation that have evaporated. The Walker River, groundwater along the Wassuk Range, and Walker Lake plot along one evaporation line. Groundwater along th

Lopes, Thomas J.; Allander, Kip K.

2009-01-01

200

Validation and Calibration of the SWAT Hydrological Model and SNTHERM Snowpack Model in Watersheds of Cannonsville, New York  

NASA Astrophysics Data System (ADS)

The science behind hydrology is on the move for major advances in the hydrological measurements, new methods for analyzing data about hydrology, and on the move for new approaches to simulate the hydrological systems. The focus in this research is to advance the hydrological science. The main objective is to ask: how to develop better hydrological measurements, analyses, and simulate calibrated models in order to get accurate readings. Quantitative amount of data was collected to get a better visualization and understanding of what the research goal was. The two models that were used were the SWAT Model and the SNTHERM Model. They were calibrated to see which model was most accurate and closest to the NOHRSC product. Future research is still needed to improve the results.

Joseph, B. J.; Lakhankar, T.; Infante, J.; Molla, M.; Siu, J.

2013-12-01

201

A New Global River Network Database for Macroscale Hydrologic modeling  

SciTech Connect

Coarse resolution (upscaled) river networks are critical inputs for runoff routing in macroscale hydrologic models. Recently, Wu et al. (2011) developed a hierarchical Dominant River Tracing (DRT) algorithm for automated extraction and spatial upscaling of basin flow directions and river networks using fine-scale hydrography inputs (e.g., flow direction, river networks, and flow accumulation). The DRT was initially applied using HYDRO1K baseline fine-scale hydrography inputs and the resulting upscaled global hydrography maps were produced at several spatial scales, and verified against other available regional and global datasets. New baseline fine-scale hydrography data from HydroSHEDS are now available for many regions and provide superior scale and quality relative to HYDRO1K. However, HydroSHEDS does not cover regions above 60°N. In this study, we applied the DRT algorithms using combined HydroSHEDS and HYDRO1K global fine-scale hydrography inputs, and produced a new series of upscaled global river network data at multiple (1/16° to 2°) spatial resolutions in a consistent (WGS84) projection. The new upscaled river networks are internally consistent and congruent with the baseline fine-scale inputs. The DRT results preserve baseline fine-scale river networks independent of spatial scales, with consistency in river network, basin shape, basin area, river length, and basin internal drainage structure between upscaled and baseline fine-scale hydrography. These digital data are available online for public access (ftp://ftp.ntsg.umt.edu/pub/data/DRT/) and should facilitate improved regional to global scale hydrological simulations, including runoff routing and river discharge calculations.

Wu, Huan; Kimball, John S.; Li, Hongyi; Huang, Maoyi; Leung, Lai-Yung R.; Adler, Robert F.

2012-09-28

202

Influences of Soil Dataset Resolution on Hydrologic Modeling  

NASA Astrophysics Data System (ADS)

Soils represent a fundamental abiotic parameter in defining the characteristics of an ecosystem. The U.S. Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) produces the most detailed digital spatial soil datasets that are publicly available. The Soil Survey Geographic (SSURGO) database contains basic attributes for the continuous coverage of soils across the United States. In its standard format, the SSURGO database is incompatible for use within the ArcView Soil and Water Assessment Tool (SWAT). A modified version of the State Soil and Geographic (STATSGO) database is the template soils dataset used by ArcView SWAT. This paper presents the methodology and development of a SSURGO database preprocessor extension for the ArcView SWAT model. A case study for the Upper Sabinal River Watershed near Uvalde, Texas, is given. Results indicate that hydrologic output parameter differences occur when comparing the STATSGO and SSURGO database information in the ArcView SWAT model under identical modeling conditions. Specifically, the SSURGO model produced a greater daily mean water yield with evapotranspiration and surface runoff being found consistently lower across the watershed. The most likely causes assigned to this phenomenon were higher percolation and resulting ground water return flow values due to significantly larger saturated hydraulic conductivity values associated with the SSURGO 2.x database.

Peschel, Joshua M.; Haan, Patricia K.; Lacey, Ronald E.

2006-10-01

203

Hydrologic Characterization for Spring Creek and Hydrologic Budget and Model Scenarios for Sheridan Lake, South Dakota, 1962-2007  

USGS Publications Warehouse

The U.S. Geological Survey cooperated with South Dakota Game, Fish and Parks to characterize hydrologic information relevant to management of water resources associated with Sheridan Lake, which is formed by a dam on Spring Creek. This effort consisted primarily of characterization of hydrologic data for a base period of 1962 through 2006, development of a hydrologic budget for Sheridan Lake for this timeframe, and development of an associated model for simulation of storage deficits and drawdown in Sheridan Lake for hypothetical release scenarios from the lake. Historically, the dam has been operated primarily as a 'pass-through' system, in which unregulated outflows pass over the spillway; however, the dam recently was retrofitted with an improved control valve system that would allow controlled releases of about 7 cubic feet per second (ft3/s) or less from a fixed depth of about 60 feet (ft). Development of a hydrologic budget for Sheridan Lake involved compilation, estimation, and characterization of data sets for streamflow, precipitation, and evaporation. The most critical data need was for extrapolation of available short-term streamflow records for Spring Creek to be used as the long-term inflow to Sheridan Lake. Available short-term records for water years (WY) 1991-2004 for a gaging station upstream from Sheridan Lake were extrapolated to WY 1962-2006 on the basis of correlations with streamflow records for a downstream station and for stations located along two adjacent streams. Comparisons of data for the two streamflow-gaging stations along Spring Creek indicated that tributary inflow is approximately proportional to the intervening drainage area, which was used as a means of estimating tributary inflow for the hydrologic budget. Analysis of evaporation data shows that sustained daily rates may exceed maximum monthly rates by a factor of about two. A long-term (1962-2006) hydrologic budget was developed for computation of reservoir outflow from Sheridan Lake for the historical pass-through operating system. Two inflow components (stream inflow and precipitation) and one outflow component (evaporation) were considered. The hydrologic budget uses monthly time steps within a computational year that includes two 6-month periods - May through October, for which evaporation is accounted for, and November through April, when evaporation is considered negligible. Results indicate that monthly evaporation rates can substantially exceed inflow during low-flow periods, and potential exists for outflows to begin approaching zero-flow conditions substantially prior to the onset of zero-inflow conditions, especially when daily inflow and evaporation are considered. Results also indicate that September may be the month for greatest potential benefit for enhancing fish habitat and other ecosystem values in downstream reaches of Spring Creek with managed releases of cool water. Computed monthly outflows from Sheridan Lake for September are less than 1.0 ft3/s for 8 of the 44 years (18 percent) and are less than 2.0 ft3/s for 14 of the 44 years (32 percent). Conversely, none of the computed outflows for May are less than 2.0 ft3/s. A short-term (July through September 2007) data set was used to calculate daily evaporation from Sheridan Lake and to evaluate the applicability of published pan coefficients. Computed values of pan coefficients of approximately 1.0 and 1.1 for two low-flow periods are larger than the mean annual pan coefficient of 0.74 for the area that is reported in the literature; however, the computed values are consistent with pan coefficients reported elsewhere for similar late summer and early fall periods. Thus, these results supported the use of variable monthly pan coefficients for the long-term hydrologic budget. A hydrologic model was developed using the primary components of the hydrologic budget and was used to simulate monthly storage deficits and drawdown for Sheridan Lake using hypothetical

Driscoll, Daniel G.; Norton, Parker A.

2009-01-01

204

Use of regional climate model output for hydrologic simulations  

USGS Publications Warehouse

Daily precipitation and maximum and minimum temperature time series from a regional climate model (RegCM2) configured using the continental United States as a domain and run on a 52-km (approximately) spatial resolution were used as input to a distributed hydrologic model for one rainfall-dominated basin (Alapaha River at Statenville, Georgia) and three snowmelt-dominated basins (Animas River at Durango. Colorado; east fork of the Carson River near Gardnerville, Nevada: and Cle Elum River near Roslyn, Washington). For comparison purposes, spatially averaged daily datasets of precipitation and maximum and minimum temperature were developed from measured data for each basin. These datasets included precipitation and temperature data for all stations (hereafter, All-Sta) located within the area of the RegCM2 output used for each basin, but excluded station data used to calibrate the hydrologic model. Both the RegCM2 output and All-Sta data capture the gross aspects of the seasonal cycles of precipitation and temperature. However, in all four basins, the RegCM2- and All-Sta-based simulations of runoff show little skill on a daily basis [Nash-Sutcliffe (NS) values range from 0.05 to 0.37 for RegCM2 and -0.08 to 0.65 for All-Sta]. When the precipitation and temperature biases are corrected in the RegCM2 output and All-Sta data (Bias-RegCM2 and Bias-All, respectively) the accuracy of the daily runoff simulations improve dramatically for the snowmelt-dominated basins (NS values range from 0.41 to 0.66 for RegCM2 and 0.60 to 0.76 for All-Sta). In the rainfall-dominated basin, runoff simulations based on the Bias-RegCM2 output show no skill (NS value of 0.09) whereas Bias-All simulated runoff improves (NS value improved from - 0.08 to 0.72). These results indicate that measured data at the coarse resolution of the RegCM2 output can be made appropriate for basin-scale modeling through bias correction (essentially a magnitude correction). However, RegCM2 output, even when bias corrected, does not contain the day-to-day variability present in the All-Sta dataset that is necessary for basin-scale modeling. Future work is warranted to identify the causes for systematic biases in RegCM2 simulations, develop methods to remove the biases, and improve RegCM2 simulations of daily variability in local climate.

Hay, L.E.; Clark, M.P.; Wilby, R.L.; Gutowski, W.J.; Leavesley, G.H.; Pan, Z.; Arritt, R.W.; Takle, E.S.

2002-01-01

205

Calibration of a Hydrologic Model Considering Input Uncertainty in Assessing Climate Change Impact on Streamflow  

NASA Astrophysics Data System (ADS)

Studies on impact assessment and the corresponding uncertainties in hydrologic regime predictions is of paramount in developing water resources management plans under climate change scenarios,. The variability in hydrologic model parameters is one of the major sources of uncertainties associated with climate change impact on streamflow. Uncertainty in hydrologic model parameters may arise from the choice of model calibration technique, model calibration period, model structure and response variables. The recent studies show that consideration of uncertainties in input variables (precipitation, evapotranspiration etc.) during calibration of a hydrologic model has resulted in decrease in prediction uncertainty. The present study has examined the significance of input uncertainty in hydrologic model calibration for climate change impact studies. A physically distributed hydrologic model, Soil and Water Assessment Tool (SWAT), is calibrated considering uncertainties in (i) model parameters only, and (ii) both model parameters and precipitation input. The Markov chain Monte Carlo algorithm is used to estimate the posterior probability density function of hydrologic model parameters. The observed daily precipitation and streamflow data of the Canard River watershed of Essex region, Ontario, Canada are used as input and output variables, respectively, during calibration. The parameter sets of the 100 most skillful hydrologic model simulations obtained from each calibration technique are used for predicting streamflow by 2070s under climate change conditions. In each run, the climate predictions of the Canadian Regional Climate Model (CRCM) for SRES scenario A2 are used as input to the hydrologic model for streamflow prediction. The paper presents the results of uncertainty in seasonal and annual streamflow prediction. The outcome of the study is expected to contribute to the assessment of uncertainty in climate change impact studies and better management of available water resources.

Bolisetti, T.; Datta, A. R.; Balachandar, R.

2009-05-01

206

Significance of hydrological model choice and land use changes when doing climate change impact assessment  

NASA Astrophysics Data System (ADS)

Uncertainty in impact studies arises both from Global Climate Models (GCM), emission projections, statistical downscaling, Regional Climate Models (RCM), hydrological models and calibration techniques (Refsgaard et al. 2013). Some of these uncertainties have been evaluated several times in the literature; however few studies have investigated the effect of hydrological model choice on the assessment results (Boorman & Sefton 1997; Jiang et al. 2007; Bastola et al. 2011). These studies have found that model choice results in large differences, up to 70%, in the predicted discharge changes depending on the climate input. The objective of the study is to investigate the impact of climate change on hydrology of the Odense catchment, Denmark both in response to (a) different climate projections (GCM-RCM combinations); (b) different hydrological models and (c) different land use scenarios. This includes: 1. Separation of the climate model signal; the hydrological model signal and the land use signal 2. How do the different hydrological components react under different climate and land use conditions for the different models 3. What land use scenario seems to provide the best adaptation for the challenges of the different future climate change scenarios from a hydrological perspective? Four climate models from the ENSEMBLES project (Hewitt & Griggs 2004): ECHAM5 - HIRHAM5, ECHAM5 - RCA3, ARPEGE - RM5.1 and HadCM3 - HadRM3 are used, assessing the climate change impact in three periods: 1991-2010 (present), 2041-2060 (near future) and 2081-2100 (far future). The four climate models are used in combination with three hydrological models with different conceptual layout: NAM, SWAT and MIKE SHE. Bastola, S., C. Murphy and J. Sweeney (2011). "The role of hydrological modelling uncertainties in climate change impact assessments of Irish river catchments." Advances in Water Resources 34: 562-576. Boorman, D. B. and C. E. M. Sefton (1997). "Recognising the uncertainty in the quantification of the effects of climate change on hydrological response." Climate Change 35: 415-434. Hewitt, C. D. and D. J. Griggs (2004). "Ensembles-based predictions of climate changes and their impacts." Eos, Transactions American Geophysical Union 85: 1-566. Jiang, T., Y. D. Chen, C. Xu, X. Chen, X. Chen and V. P. Singh (2007). "Comparison of hydrological impacts of climate change simulated by six hydrological models in the Dongjiang Basin, South China." Journal of hydrology 336: 316-333. Refsgaard, J. C., K. Arnbjerg-Nielsen, M. Drews, K. Halsnæs, E. Jeppesen, H. Madsen, A. Markandya, J. E. Olesen, J. R. Porter and J. H. Christensen (2013). "The role of uncertainty in climate change adaptation strategies - A Danish water management example." Mitigation and Adaptation Strategies for Global Change 18: 337-359.

Bjørnholt Karlsson, Ida; Obel Sonnenborg, Torben; Refsgaard, Jens Christian; Høgh Jensen, Karsten

2014-05-01

207

Satellite Remote Sensing and Hydrological Modeling for Flood Inundation Mapping in Lake Victoria Basin: Implications for Hydrologic Prediction in Ungauged Basins  

NASA Astrophysics Data System (ADS)

Floods are among the most catastrophic natural disasters around the globe impacting human lives and infrastructure. Implementation of a flood prediction system can potentially reduce these losses. Typically, the set up and calibration of a hydrologic model requires in situ observations (e.g. rain gauges and stream gauges). Satellite remote sensing data have emerged as viable alternatives or supplements to in situ observations due to their coverage over ungauged regions. The focus of this study is to utilize the best available satellite products and integrate them in a state-of-the-art hydrologic model to characterize the spatial extent of flooding and associated hazards over sparsely-gauged or ungauged basins. This study presents a methodology based entirely on satellite remote sensing data to calibrate a hydrologic model, simulate the spatial extent of flooding, and evaluate the probability of detecting inundated areas. A raster-based distributed hydrologic model, CREST, was implemented for the Nzoia basin, a sub-basin of Lake Victoria (Africa). MODIS- and ASTER-based flood inundation maps were retrieved over the region and used to benchmark the distributed hydrologic model simulations of streamflow and inundation areas. The analysis showed the applicability of integrating satellite data products as input for a distributed hydrological model as well as direct estimation of flood extent maps. The quantification of flooding spatial extent through orbital sensors can help to evaluate hydrologic models and hence potentially improve hydrologic prediction and flood management strategies in ungauged catchments.

Khan, S. I.; Hong, Y.; Wang, J.; Yilmaz, K. K.; Gourley, J. J.; Adler, R. F.; Brakenridge, G. R.; Policelli, F.; Habib, S.; Irwin, D.

2009-12-01

208

Relationship between HBV cccDNA expression in the human ovary and vertical transmission of HBV.  

PubMed

This study aimed to investigate the relationship between hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) in the ovary and vertical transmission of HBV. HBV DNA and HBV cccDNA were assayed in the ovaries of 33 pregnant women who were positive for HBV DNA. The HBVM (HBV markers, including HBsAg, HBsAb, HBeAg, HBeAb, HBcAb) level and the HBV DNA content in peripheral blood of infants were measured. The overall positive rate of HBV DNA and HBV cccDNA in samples was 51·52% (17/33). The intrauterine infection rate of the infants was 12·12% (4/33). When HBV DNA and HBV cccDNA were both positive, the intrauterine infection rate of infants was significantly higher than when they were both negative (P<0·05). Levels of HBV cccDNA and the rate of positive samples were significantly higher in mothers with infants with intrauterine infection than in those without (P<0·01 and P<0·05, respectively). HBV can infect the human ovary and may transmit to the filial generation via the ovum. PMID:22000033

Yu, M M; Gu, X J; Xia, Y; Wang, G J; Kan, N Y; Jiang, H X; Wu, K H; Ji, Y; Ju, L L

2012-08-01

209

Regional scale hydrology with a new land surface processes model  

NASA Technical Reports Server (NTRS)

Through the CaPE Hydrometeorology Project, we have developed an understanding of some of the unique data quality issues involved in assimilating data of disparate types for regional-scale hydrologic modeling within a GIS framework. Among others, the issues addressed here include the development of adequate validation of the surface water budget, implementation of the STATSGO soil data set, and implementation of a remote sensing-derived landcover data set to account for surface heterogeneity. A model of land surface processes has been developed and used in studies of the sensitivity of surface fluxes and runoff to soil and landcover characterization. Results of these experiments have raised many questions about how to treat the scale-dependence of land surface-atmosphere interactions on spatial and temporal variability. In light of these questions, additional modifications are being considered for the Marshall Land Surface Processes Model. It is anticipated that these techniques can be tested and applied in conjunction with GCIP activities over regional scales.

Laymon, Charles; Crosson, William

1995-01-01

210

Impact of modellers' decisions on hydrological a priori predictions  

NASA Astrophysics Data System (ADS)

In practice, the catchment hydrologist is often confronted with the task of predicting discharge without having the needed records for calibration. Here, we report the discharge predictions of 10 modellers - using the model of their choice - for the man-made Chicken Creek catchment (6 ha, northeast Germany, Gerwin et al., 2009b) and we analyse how well they improved their prediction in three steps based on adding information prior to each following step. The modellers predicted the catchment's hydrological response in its initial phase without having access to the observed records. They used conceptually different physically based models and their modelling experience differed largely. Hence, they encountered two problems: (i) to simulate discharge for an ungauged catchment and (ii) using models that were developed for catchments, which are not in a state of landscape transformation. The prediction exercise was organized in three steps: (1) for the first prediction the modellers received a basic data set describing the catchment to a degree somewhat more complete than usually available for a priori predictions of ungauged catchments; they did not obtain information on stream flow, soil moisture, nor groundwater response and had therefore to guess the initial conditions; (2) before the second prediction they inspected the catchment on-site and discussed their first prediction attempt; (3) for their third prediction they were offered additional data by charging them pro forma with the costs for obtaining this additional information. Holländer et al. (2009) discussed the range of predictions obtained in step (1). Here, we detail the modeller's assumptions and decisions in accounting for the various processes. We document the prediction progress as well as the learning process resulting from the availability of added information. For the second and third steps, the progress in prediction quality is evaluated in relation to individual modelling experience and costs of added information. In this qualitative analysis of a statistically small number of predictions we learned (i) that soft information such as the modeller's system understanding is as important as the model itself (hard information), (ii) that the sequence of modelling steps matters (field visit, interactions between differently experienced experts, choice of model, selection of available data, and methods for parameter guessing), and (iii) that added process understanding can be as efficient as adding data for improving parameters needed to satisfy model requirements.

Holländer, H. M.; Bormann, H.; Blume, T.; Buytaert, W.; Chirico, G. B.; Exbrayat, J.-F.; Gustafsson, D.; Hölzel, H.; Krauße, T.; Kraft, P.; Stoll, S.; Blöschl, G.; Flühler, H.

2014-06-01

211

ORIGINAL ARTICLE Integration of hydrologic and water allocation models in basin-  

E-print Network

hydropower production of Karkheh dam is 600 GWH (Iran Water and Power Resources Development Co 2010ORIGINAL ARTICLE Integration of hydrologic and water allocation models in basin- scale water water resources management requires coupled analysis of hydrology and water resources in a river basin

212

Root Zone Soil Moisture Assessment Using Passive Microwave Remote Sensing and Distributed Hydrologic Modeling  

Microsoft Academic Search

Soil moisture is a fundamental state variable and it varies spatially due to topography, soil, precipitation variability and landuse-landcover, and temporally, due to difference in hydrologic characteristics and controls. Estimation of profile soil moisture using remotely sensed land surface moisture data with the combination of forward soil hydrologic modeling is very promising. This integrated method may become resourceful solution to

N. N. Das; B. Mohanty

2004-01-01

213

Evaluation of ensemble-based distributed hydrologic model response with disaggregated precipitation products  

Microsoft Academic Search

The disaggregation of coarse precipitation products is desirable for spatially distributed hydrological applications where high-resolution rainfall fields are required. In this study, we generate an ensemble of satellite-based precipitation estimates using a spatiotemporal disaggregation framework for use in a spatially explicit hydrologic model. The framework effectively reproduced small, localized storm events using coarse precipitation estimates while simultaneously including known error

Barton A. Forman; Enrique R. Vivoni; Steven A. Margulis

2008-01-01

214

Land Surface Hydrology Parameterization for Atmospheric General Circulation models Including Subgrid Scale Spatial Variability  

Microsoft Academic Search

Parameterizations are developed for the representation of subgrid hydrologic processes in atmospheric general circulation models. Reasonable a priori probability density functions of the spatial variability of soil moisture and of precipitation are introduced. These are used in conjunction with the deterministic equations describing basic soil moisture physics to derive expressions for the hydrologic processes that include subgrid scale variation in

D. Entekhabi; P. S. Eagleson

1989-01-01

215

PREDICTIVE UNCERTAINTY IN HYDROLOGIC AND WATER QUALITY MODELING: APPROACHES, APPLICATION TO ENVIRONMENTAL MANAGEMENT, AND FUTURE CHALLENGES  

EPA Science Inventory

Extant process-based hydrologic and water quality models are indispensable to water resources planning and environmental management. However, models are only approximations of real systems and often calibrated with incomplete and uncertain data. Reliable estimates, or perhaps f...

216

Developing a TeraGrid Based Land Surface Hydrology and Weather Modeling Interface  

E-print Network

on the quality of air, land, and water resources. The computation-intensive models are supported by resourcesDeveloping a TeraGrid Based Land Surface Hydrology and Weather Modeling Interface Hsin-I Chang1

Jiang, Wen

217

Modeling the impact of hydrological changes on nitrate transport in the Mississippi River Basin from 1955 to 1994  

Microsoft Academic Search

The export of nitrate by the Mississippi River to the Gulf of Mexico has tripled since the 1950s primarily due to an increase in agricultural fertilizer application and hydrological changes. Here we have adapted two physically based models, the Integrated Biosphere Simulator (IBIS) terrestrial ecosystem model and the Hydrological Routing Algorithm (HYDRA) hydrological transport model, to simulate the nitrate export

Simon D. Donner; Michael T. Coe; John D. Lenters; Tracy E. Twine; Jonathan A. Foley

2002-01-01

218

Statistical procedures for evaluating daily and monthly hydrologic model predictions  

USGS Publications Warehouse

The overall study objective was to evaluate the applicability of different qualitative and quantitative methods for comparing daily and monthly SWAT computer model hydrologic streamflow predictions to observed data, and to recommend statistical methods for use in future model evaluations. Statistical methods were tested using daily streamflows and monthly equivalent runoff depths. The statistical techniques included linear regression, Nash-Sutcliffe efficiency, nonparametric tests, t-test, objective functions, autocorrelation, and cross-correlation. None of the methods specifically applied to the non-normal distribution and dependence between data points for the daily predicted and observed data. Of the tested methods, median objective functions, sign test, autocorrelation, and cross-correlation were most applicable for the daily data. The robust coefficient of determination (CD*) and robust modeling efficiency (EF*) objective functions were the preferred methods for daily model results due to the ease of comparing these values with a fixed ideal reference value of one. Predicted and observed monthly totals were more normally distributed, and there was less dependence between individual monthly totals than was observed for the corresponding predicted and observed daily values. More statistical methods were available for comparing SWAT model-predicted and observed monthly totals. The 1995 monthly SWAT model predictions and observed data had a regression Rr2 of 0.70, a Nash-Sutcliffe efficiency of 0.41, and the t-test failed to reject the equal data means hypothesis. The Nash-Sutcliffe coefficient and the R r2 coefficient were the preferred methods for monthly results due to the ability to compare these coefficients to a set ideal value of one.

Coffey, M. E.; Workman, S. R.; Taraba, J. L.; Fogle, A. W.

2004-01-01

219

An educational model for ensemble streamflow simulation and uncertainty analysis  

NASA Astrophysics Data System (ADS)

This paper presents a hands-on modeling toolbox, HBV-Ensemble, designed as a complement to theoretical hydrology lectures, to teach hydrological processes and their uncertainties. The HBV-Ensemble can be used for in-class lab practices and homework assignments, and assessment of students' understanding of hydrological processes. Using this model, students can gain more insights into how hydrological processes (e.g., precipitation, snowmelt and snow accumulation, soil moisture, evapotranspiration and runoff generation) are interconnected. The model includes a MATLAB Graphical User Interface (GUI) and an ensemble simulation scheme that can be used for not only hydrological processes, but also for teaching uncertainty analysis, parameter estimation, ensemble simulation and model sensitivity.

AghaKouchak, A.; Nakhjiri, N.; Habib, E.

2012-06-01

220

An Open Source modular platform for hydrological model implementation  

NASA Astrophysics Data System (ADS)

An implementation framework for setup and evaluation of spatio-temporal models is developed, forming a highly modularized distributed model system. The ENKI framework allows building space-time models for hydrological or other environmental purposes, from a suite of separately compiled subroutine modules. The approach makes it easy for students, researchers and other model developers to implement, exchange, and test single routines in a fixed framework. The open-source license and modular design of ENKI will also facilitate rapid dissemination of new methods to institutions engaged in operational hydropower forecasting or other water resource management. Written in C++, ENKI uses a plug-in structure to build a complete model from separately compiled subroutine implementations. These modules contain very little code apart from the core process simulation, and are compiled as dynamic-link libraries (dll). A narrow interface allows the main executable to recognise the number and type of the different variables in each routine. The framework then exposes these variables to the user within the proper context, ensuring that time series exist for input variables, initialisation for states, GIS data sets for static map data, manually or automatically calibrated values for parameters etc. ENKI is designed to meet three different levels of involvement in model construction: • Model application: Running and evaluating a given model. Regional calibration against arbitrary data using a rich suite of objective functions, including likelihood and Bayesian estimation. Uncertainty analysis directed towards input or parameter uncertainty. o Need not: Know the model's composition of subroutines, or the internal variables in the model, or the creation of method modules. • Model analysis: Link together different process methods, including parallel setup of alternative methods for solving the same task. Investigate the effect of different spatial discretization schemes. o Need not: Write or compile computer code, handle file IO for each modules, • Routine implementation and testing. Implementation of new process-simulating methods/equations, specialised objective functions or quality control routines, testing of these in an existing framework. o Need not: Implement user or model interface for the new routine, IO handling, administration of model setup and run, calibration and validation routines etc. From being developed for Norway's largest hydropower producer Statkraft, ENKI is now being turned into an Open Source project. At the time of writing, the licence and the project administration is not established. Also, it remains to port the application to other compilers and computer platforms. However, we hope that ENKI will prove useful for both academic and operational users.

Kolberg, Sjur; Bruland, Oddbjørn

2010-05-01

221

An international standard conceptual model for sharing references to hydrologic features  

NASA Astrophysics Data System (ADS)

SummaryConcepts such as catchment, basin, watershed and river are commonly understood in many fields of discourse, but are described differently according to the focus on various aspects of the hydrology phenomenon. The effective exchange of hydrologic data containing references to hydrologic features requires standardised semantics of the concepts that allow identification of these features. Here, the scope of common approaches to information modelling of hydrologic features is examined, and is compared to the requirements for feature identification in multiple contexts. A conceptual model is presented that reconciles the underlying differences in representation of hydrologic features and levels of detail in typical datasets. By providing a stable and common referencing system for hydrologic features, the model will assist in the organization of observation and modelling of such features, and in the aggregation of generated data on a global, regional, national or basin scale. The model encompasses a number of approaches used in different contexts to identify and model hydrologic features and enforce the semantics of relationships between different levels of detail. Thus, it provides a semantic framework for common feature identifiers to be developed and embedded in individual data products, while providing the flexibility to model complex hydrological processes at fine detail. The common identifiers can be used in aggregating data generated using high-detail models of processes, and in partitioning large and complex hydrologic feature datasets into local study areas. Different local models can be applied according to the dominant hydrologic processes and the amount of hydrometric monitoring available for each region. The model is intended to form the basis for standard practices under the auspices of the World Meteorological Organization Commission for Hydrology. It is presented here to invite further testing, feedback and engagement in the process of its acceptance and implementation as an international standard for hydrologic feature identification. Based on the accepted International Organization for Standardization General Feature Model, it will be possible to realise, in a standardised way, the semantics of feature identification in tools for managing metadata documenting hydrologic datasets and products.

Atkinson, Robert; Dornblut, Irina; Smith, Darren

2012-03-01

222

Sensitivity of an ecological model to soil moisture simulations from two different hydrological models  

Microsoft Academic Search

Summary  Although advanced land surface schemes have been developed in the past decade, many biosphere models still use the simple\\u000a bucket model, partly due to its efficiency when it is coupled with an CGCM model. In this paper, we use a sophisticated land\\u000a surface model, the Simulator for Hydrology and Energy Exchange at the Land Surface (SHEELS), including an explicit vegetation

D. Ren; L. M. Leslie; D. J. Karoly

2008-01-01

223

Test and Sensitivity Analysis of Hydrological Modeling in the Coupled WRF-Urban Modeling System  

NASA Astrophysics Data System (ADS)

Rapid urbanization has emerged as the source of many adverse effects that challenge the environmental sustainability of cities under changing climatic patterns. One essential key to address these challenges is to physically resolve the dynamics of urban-land-atmospheric interactions. To investigate the impact of urbanization on regional climate, physically-based single layer urban canopy model (SLUCM) has been developed and implemented into the Weather Research and Forecasting (WRF) platform. However, due to the lack of realistic representation of urban hydrological processes, simulation of urban climatology by current coupled WRF-SLUCM is inevitably inadequate. Aiming at improving the accuracy of simulations, recently we implemented urban hydrological processes into the model, including (1) anthropogenic latent heat, (2) urban irrigation, (3) evaporation over impervious surface, and (4) urban oasis effect. In addition, we couple the green roof system into the model to verify its capacity in alleviating urban heat island effect at regional scale. Driven by different meteorological forcings, offline tests show that the enhanced model is more accurate in predicting turbulent fluxes arising from built terrains. Though the coupled WRF-SLUCM has been extensively tested against various field measurement datasets, accurate input parameter space needs to be specified for good model performance. As realistic measurements of all input parameters to the modeling framework are rarely possible, understanding the model sensitivity to individual parameters is essential to determine the relative importance of parameter uncertainty to model performance. Thus we further use an advanced Monte Carlo approach to quantify relative sensitivity of input parameters of the hydrological model. In particular, performance of two widely used soil hydraulic models, namely the van Genuchten model (based on generic soil physics) and an empirical model (viz. the CHC model currently adopted in WRF-SLUCM) is investigated. Results show that the CHC model requires a much finer time step for numerical stability in hydrological modeling and thus is more computationally expensive in the coupled WRF-SLUCM modeling environment.

Wang, Z.; yang, J.

2013-12-01

224

What have we learned by applying the data driven modelling techniques in the field of hydrological modelling?  

NASA Astrophysics Data System (ADS)

Hydrologic data analysis and hydrologic modelling have become major techniques in hydrology and are used for building hydrologic models to generate synthetic hydrologic records, to forecast hydrologic events, to detect trends and shifts in hydrologic records and to fill in missing data and extend the data sets. Well known, praised and widely used are the so-called conceptual models that are based on the prior theoretical knowledge of all the hydrological processes in the form of theoretically developed or empirically derived equations. A modeller needs a lot of detailed data like river network, land cover, soil characteristics and other geographical data or topographical maps to sucessfully calibrate a conceptual model. The availability of all of the aforementioned data can present quite a significant problem in the process of modelling. On the basis of different approaches to the inclusion of geographical, topographical and other data in conceptual models, we distinguish between distributed, semi-distributed and lumped conceptual models. Empirical, mostly black box models simply connecting input and output hydrolgical data have also been widely used in the field of hydrology, especially in the hydrological praxis. Data driven modelling on the other hand is based on the analysis of the data characterising the system being modelled, which in most cases means finding the best type of model or combination of those to connect the input and output data characterising the system being modelled, while the assumptions or learning about the physical bases of the system being modelled are not the top priority. Also, there is still a lot of scepticism among many hydrologists regarding the usage of data driven modelling techniques in hydrology, because the development of the models from the data is usually seen as a computational exercise and is not related to physical principles and mathematical reasoning. This presentation will give a quick overview of more and less successfull applications of some of the data driven modelling techniques in Slovenian hydrological practice (modelling the flow duration curves and estimation of the regional flow duration curve, precipitation interception modelling, low flow and flood forecasting, etc.) and will try to systematically list the pros and cons of using these methods in hydrology. Based on our experience these methods present a very useful way for quick (especially by reducing the man-power spent in the process of model calibration and verification) development of empirically based forecasting models, which in some cases can also provide a firm basis for learning more about the hydrological processes in the particular river basin.

Stravs, Luka; Brilly, Mitja

2010-05-01

225

Accesible hydrological monitoring for better decision making and modelling: a regional initiative in the Andes  

NASA Astrophysics Data System (ADS)

The goal of the Hydrological Monitoring of Andean Ecosystems Initiative is to improve the conservation and management of High-Andean ecosystems by providing information on the hydrological response of these ecosystems and how different land-uses affect their water yield and regulation capacity. The initiative fills a gap left by widespread hydrological modeling exercises that suffer from lack of data, and by glacier monitoring under climate change. The initiative proposes a hydrological monitoring system involving precipitation, discharge and land cover monitoring in paired catchments. The methodology is accessible for non-specialist organizations, and allows for generation of evidence of land use impact on hydrology on the short term (i.e. a few years). Nevertheless, long term monitoring is pursued with the aim of identifying trends in hydrological response (as opposed to trends in climate) under global change. In this way it supports decision making on the preservation of the hydrological services of the catchment. The initiative aims at a high number of paired catchment sites along the Andes, in order to draw regional conclusions and capture variability, and is connected to more detailed hydrological research sites of several Andean universities. We present preliminary results of a dozen of sites from Venezuela to Bolivia, summarized in hydrological performance indicators that were agreed upon among hydrologists, local stakeholders, and water authorities. The success factors, as well as limitations, of the network are discussed.

De Bievre, B.; Célleri, R.; Crespo, P.; Ochoa, B.; Buytaert, W.; Tobón, C.; Villacís, M.; Villazon, M. F.; Llerena, C.; Rodriguez, M.; Viñas, P.

2013-05-01

226

New hydrologic model of fluid migration in deep porous media  

NASA Astrophysics Data System (ADS)

The authors present a new hydrological model of mantle processes that effect on formation of oil-and-gas bearing basins, fault tectonics and thermal convection. Any fluid migration is initially induced by lateral stresses in the crust and lithosphere which result from global geodynamic processes related to the mantle convection. The global processes are further transformed into regional movements in weakness zones. Model of porous media in deep fractured zones and idea of self-oscillation processes in mantle layers and fractured zones of the crust at different depths was used as the basis for developed concept. The content of these notions resides in the fact that there are conditions of dynamic balance in mantle layers originating as a result of combination and alternate actions of compaction and dilatance mechanisms. These mechanisms can be manifested in different combinations and under different conditions as well as can be complemented by other processes influencing on regime of fluid migration. They can act under condition of passive margin, ocean rift and ocean subduction zones as well as in consolidated platform and sheet. Self-oscillation regime, sub vertical direction of fluid flows, anomalously high layer pressure, and high level of anomalies of various geophysical fields are common for them. A certain class of fluid dynamic models describing consolidation of sedimentary basins, free oscillation processes slow and quick (at the final stage) fluid dynamic processes of the evolution of a sedimentary basin in subduction zones is considered for the first time. The last model of quick fluid dynamic processes reflects the process of formation of hydrocarbon deposits in the zones of collision of lithosphere plates. The results of numerical simulation and diagrams reflecting consecutive stages of the gas-fluid dynamic front propagation are assessed of the Pri-Caspian depression as the example. Calculations with this model will simultaneously be carried out for the sedimentary basins of Timan-Pechora region, Barents Sea, Volga-Ural area, etc. Hydrologic model of deep porous media and the idea of self-oscillation processes in fractured layers of the crust at different depths were used as the basis for developed concept. The content of these notions resides in the fact that there are conditions of dynamic balance in fractured layers originating as a result of combination and alternate actions of compaction and dilatance mechanisms. These mechanisms can be manifested in different combinations and under different conditions as well as can be complemented by other processes influencing on regime of fluid migration. They can act under condition of passive margin, rift and subduction zones as well as in consolidated platform and sheet. Self-oscillation regime, sub vertical direction of fluid flows, anomalously high layer pressure, and high level of anomalies of various geophysical fields are common for them. Specific manifestations of these mechanisms can vary in dependence on geological settings and geodynamic situations. In particular, periods of self-oscillations and depths of fractured layers can be various. Orientation of layers can be not only horizontal, but vertical as well, that is, self-oscillations can occur not only in deep porous media, but in faults and impaired fractured zones as well. Predominating vertical fluid migration can be accompanied by horizontal migration along crust waveguide. A set of fluid dynamic models is considered. Mathematical modeling of geodynamic and fluid dynamic processes in these zones seems very promising. Combined consideration of geodynamic and fluid dynamic aspects in a model of lithosphere plates collision enables to understand the influence of P-T conditions and shear deformations on the mechanism of hydrocarbon generation and to look after their migration and to explain these processes, but also to predict some features essential for the search and exploration of hydrocarbon fields in these regions and their classification. In terms of compaction models, multiphase filtration in a

Dmitrievsky, A.; Balanyuk, I.

2009-04-01

227

Hydrological improvements for nutrient and pollutant emission modeling in large scale catchments  

NASA Astrophysics Data System (ADS)

An estimation of emissions and loads of nutrients and pollutants into European water bodies with as much accuracy as possible depends largely on the knowledge about the spatially and temporally distributed hydrological runoff patterns. An improved hydrological water balance model for the pollutant emission model MoRE (Modeling of Regionalized Emissions) (IWG, 2011) has been introduced, that can form an adequate basis to simulate discharge in a hydrologically differentiated, land-use based way to subsequently provide the required distributed discharge components. First of all the hydrological model had to comply both with requirements of space and time in order to calculate sufficiently precise the water balance on the catchment scale spatially distributed in sub-catchments and with a higher temporal resolution. Aiming to reproduce seasonal dynamics and the characteristic hydrological regimes of river catchments a daily (instead of a yearly) time increment was applied allowing for a more process oriented simulation of discharge dynamics, volume and therefore water balance. The enhancement of the hydrological model became also necessary to potentially account for the hydrological functioning of catchments in regard to scenarios of e.g. a changing climate or alterations of land use. As a deterministic, partly physically based, conceptual hydrological watershed and water balance model the Precipitation Runoff Modeling System (PRMS) (USGS, 2009) was selected to improve the hydrological input for MoRE. In PRMS the spatial discretization is implemented with sub-catchments and so called hydrologic response units (HRUs) which are the hydrotropic, distributed, finite modeling entities each having a homogeneous runoff reaction due to hydro-meteorological events. Spatial structures and heterogeneities in sub-catchments e.g. urbanity, land use and soil types were identified to derive hydrological similarities and classify in different urban and rural HRUs. In this way the hydrological system is simulated spatially differentiated and emissions from urban and rural areas into river courses can be detected separately. In the Ruhr catchment (4.485 km2) as a right tributary of the Rhine located in the lower mountain range of North Rhine-Westphalia in Germany for the validation period 2002-2006 the hydrological model showed first satisfying results. The feasibility study in the Ruhr shows the suitability of the approach and illustrates the potentials for further developments in terms of an implementation throughout the German and contiguous watersheds. IWG, Karlsruhe Institute of Technology (KIT). 2011. http://isww.iwg.kit.edu/MoRE.php. [Online] Institute for Water and River Basin Management, Department of Aquatic Environmental Engineering, October 2011. USGS, U.S. Geological Survey. 2009. PRMS-2009, the Precipitation-Runoff Modeling System. Denver, Colorado : s.n., 2009. Bd. U.S. Geologic Survey Open File Report.

Höllering, S.; Ihringer, J.

2012-04-01

228

Climate Change: Coupling Hydrologic Modeling with Policy Making  

E-print Network

on regional hydrologic processes. And yet, this may be the most beneficial application of hydro scenarios for water managers and policy makers. This analysis benefits the inclusion of a climatic component:......................................................................................................5 2.2.2- Regional hydro

Fay, Noah

229

Coupled Atmosphere-Biophysics-Hydrology Models for Environmental Modeling  

Microsoft Academic Search

The formulation and implementation of LEAF-2, the Land Ecosystem-Atmosphere Feedback model, which comprises the representation of land-surface processes in the Regional Atmospheric Modeling System (RAMS), is described. LEAF-2 is a prognostic model for the temperature and water content of soil, snow cover, vegetation, and canopy air, and includes turbulent and radiative exchanges between these components and with the atmosphere. Subdivision

Robert L. Walko; Larry E. Band; Jill Baron; Timothy G. F. Kittel; Richard Lammers; Tsengdar J. Lee; Dennis Ojima; Roger A. Pielke Sr.; Chris Taylor; Christina Tague; Craig J. Tremback; Pier Luigi Vidale

2000-01-01

230

The Impact of Microwave-Derived Surface Soil Moisture on Watershed Hydrological Modeling  

NASA Technical Reports Server (NTRS)

The usefulness of incorporating microwave-derived soil moisture information in a semi-distributed hydrological model was demonstrated for the Washita '92 experiment in the Little Washita River watershed in Oklahoma. Initializing the hydrological model with surface soil moisture fields from the ESTAR airborne L-band microwave radiometer on a single wet day at the start of the study period produced more accurate model predictions of soil moisture than a standard hydrological initialization with streamflow data over an eight-day soil moisture drydown.

ONeill, P. E.; Hsu, A. Y.; Jackson, T. J.; Wood, E. F.; Zion, M.

1997-01-01

231

Improving student comprehension of the interconnectivity of the hydrologic cycle with a novel 'hydrology toolbox', integrated watershed model, and companion textbook  

NASA Astrophysics Data System (ADS)

Concepts in introductory hydrology courses are often taught in the context of process-based modeling that ultimately is integrated into a watershed model. In an effort to reduce the learning curve associated with applying hydrologic concepts to real-world applications, we developed and incorporated a 'hydrology toolbox' that complements a new, companion textbook into introductory undergraduate hydrology courses. The hydrology toolbox contains the basic building blocks (functions coded in MATLAB) for an integrated spatially-distributed watershed model that makes hydrologic topics (e.g. precipitation, snow, radiation, evaporation, unsaturated flow, infiltration, groundwater, and runoff) more user-friendly and accessible for students. The toolbox functions can be used in a modular format so that students can study individual hydrologic processes and become familiar with the hydrology toolbox. This approach allows such courses to emphasize understanding and application of hydrologic concepts rather than computer coding or programming. While topics in introductory hydrology courses are often introduced and taught independently or semi-independently, they are inherently interconnected. These toolbox functions are therefore linked together at the end of the course to reinforce a holistic understanding of how these hydrologic processes are measured, interconnected, and modeled. They are integrated into a spatially-distributed watershed model or numerical laboratory where students can explore a range of topics such as rainfall-runoff modeling, urbanization, deforestation, watershed response to changes in parameters or forcings, etc. Model output can readily be visualized and analyzed by students to understand watershed response in a real river basin or a simple 'toy' basin. These tools complement the textbook, each of which has been well received by students in multiple hydrology courses with various disciplinary backgrounds. The same governing equations that students have studied in the textbook and used in the toolbox have been encapsulated in the watershed model. Therefore, the combination of the hydrology toolbox, integrated watershed model, and textbook tends to eliminate the potential disconnect between process-based modeling and an 'off-the-shelf' watershed model.

Huning, L. S.; Margulis, S. A.

2013-12-01

232

Virtual Hydrologic Environment (VHE) - Design and implementation of a GIS data model for the integration with hydrologic modeling and its application to Meijiang watershed area in East China  

NASA Astrophysics Data System (ADS)

Virtual Hydrologic Environment (VHE) is an integrated approach where two major data systems are included: integration of different types of GIS and water resources data, integration of data and modeling. The Unified Modeling Language (UML) facilitates the design of GIS based relational database model GeoHydro/DataBase(GH/DB) and is used to create a specialized set of geo- and hydro-objects from both surface and subsurface hydrology in a consistent manner. Feather classes were created to store spatial data, such as sub-catchments and steam network. Tables were created to store time series and other parameters. Relationship classes were developed to link related objects. Furthermore, a graphical user interface is implemented as a link between object- and process-oriented numerical model GeoSys/RockFlow and GH/DB for the pre- and post-processing of model data and parameters. This VHE concept is applied to the Meijiang watershed area which belongs to the Poyang lake basin, the biggest freshwater drainage area in East China. A coupled regional hydrologic soil model is developed for the understanding of surface/subsurface water interaction. The GH/DB has been populated with data from the Meijiang site. The soil compartment is directly coupled to the atmosphere via the land surface and to the aquifers. The high-resolution modeling is achieved by parallel computation techniques. VHE as a bridge between surface and subsurface hydrology can improve our understanding of the hydrologic cycle, the interactions between water, earth, ecosystems and man and its role in the context of climate change. The integration of databases and modeling by the use of methods from scientific computing and information technology leads to a comprehensive and consistent representation of the VHE and thus enhances our understanding about the interactions and coupling processes between the different compartments of the hydrologic system.

Chen, C.; Sun, F.; Lai, G. Y.; Kalbacher, T.; Kolditz, O.

2009-04-01

233

Modeling and monitoring the hydrological effects of the Sand Engine.  

NASA Astrophysics Data System (ADS)

Since 1887, Dunea Water Company produces high quality drinking water using the dune area at Monster (Province of South Holland, the Netherlands). Annually, 8 billion liters of water is produced here using artificial recharge and recovery with shallow wells and infiltration lakes. The dunes are an important step in producing drinking water serving as an underground buffer, leveling fluctuating in temperature and quality and removing bacteria and viruses from the infiltrated water in a natural way. Since space is limited in the Netherlands, the drinking water production of Dunea is closely matched with surrounding land uses and natural constraints. This prevents groundwater nuisance, upconing and intrusion of salt water and, in this case, movement of a nearby groundwater pollution. This is especially true in the Monster area where the dunes are fairly low and small; the coast is less than 350 meters from the recovery wells. The coast of Monster was identified as a weak link in the coastal defense of The Netherlands. Because of this, two coastal defense projects were carried out between 2009 and 2011. The first project involved creating an extra dune ridge in front of existing dunes which leads to intrusion of a large volume of seawater. Directly after completion, the Sand Engine was constructed. This hook shaped sand peninsula will supply the coast with sand for the coming decades due to erosion and deposition along the coast. These two large coastal defense projects would obviously influence the tightly balanced hydrological system of Monster. Without hydrological intervention, the drinking water production would no longer be sustainable in this area. To study the effects of these projects and to find a solution to combine coastal defense and drinking water supply, field research and effect (geochemical) modeling were used interactively. To prevent negative effects it was decided to construct interception wells on top of the new dune ridge (28 in total). A comprehensive monitoring system was built to keep track of the salt groundwater and the groundwater heads. The zero measurement included groundwater heads, water samples, but also geophysical methods such as SkyTEM and CVES. We will also show the monitoring system we use to keep track of the groundwater heads and salt water intrusion in the future.

Schaars, Frans; Hoogmoed, Merel; van Vliet, Frank; Stuyfzand, Pieter; Groen, Michel; van der Made, Kees-Jan; Caljé, Ruben; Auken, Esben; Bergsted Pedersen, Jesper

2013-04-01

234

Application of remote sensing to hydrology. [for the formulation of watershed behavior models  

NASA Technical Reports Server (NTRS)

Streamflow forecasting and hydrologic modelling are considered in a feasibility assessment of using the data produced by remote observation from space and/or aircraft to reduce the time and expense normally involved in achieving the ability to predict the hydrological behavior of an ungaged watershed. Existing watershed models are described, and both stochastic and parametric techniques are discussed towards the selection of a suitable simulation model. Technical progress and applications are reported and recommendations are made for additional research.

Ambaruch, R.; Simmons, J. W.

1973-01-01

235

Using remotely sensed precipitation in large-scale distributed hydrological modelling  

Microsoft Academic Search

The combination of satellite-based remote sensing and distributed hydrological modelling provides a powerful tool for hydrological prediction and forecasting. Remote sensing (RS) data can be incorporated in distributed models in a number of ways including; static input data (e.g land use classification) calibration and validation (e.g. soil moisture, vegetation status, surface temperature, evapotranspiration), data assimilation (í.e. update model variables to

Michael Butts; G. Dybkjær; M. Rasmussen; Geoff Wilson

236

Development and test of a spatially distributed hydrological\\/water quality model for mesoscale watersheds  

Microsoft Academic Search

The new watershed model SWIM was developed in order to provide a comprehensive GIS-based tool for hydrological and water quality modelling in mesoscale watersheds (from 100 to 10?000 km2), which can be parametrized using regionally available information. SWIM is based on two previously developed tools—SWAT and MATSALU. The model integrates hydrology, vegetation, erosion and nitrogen dynamics at the watershed scale.

Valentina Krysanova; Dirk-Ingmar Müller-Wohlfeil; Alfred Becker

1998-01-01

237

SWAT hydrologic model parameter uncertainty and its implications for hydroclimatic projections in snowmelt-dependent watersheds  

NASA Astrophysics Data System (ADS)

The effects of climate change on water resources have been studied extensively throughout the world through the use of hydrologic models coupled with General Circulation Model (GCM) output or climate sensitivity scenarios. This paper examines the effects of hydrologic model parameterization uncertainty or equifinality, where multiple unique hydrologic model parameter sets can result in adequate calibration metrics, on hydrologic projections from downscaled GCMs for three snowmelt-dependent watersheds (upper reaches of the Clearwater, Gunnison, and Sacramento River watersheds) in the western United States. The hydrologic model used in this study is the Soil and Water Assessment Tool (SWAT) and is calibrated for discharge at the watershed outlet in each watershed. Despite achieving similar calibration metrics, a majority of hydrologic projections of average annual streamflow during the 2080s were statistically different, with differences in magnitude and direction (increase or decrease) compared to historical annual streamflows. At the average monthly time-scale, a majority of the hydrologic projections varied in peak streamflow timing, peak streamflow magnitude, summer streamflows, as well as overall increases or decreases compared to the historical monthly streamflows. Snowmelt projections from the SWAT model also widely varied, both in depth and snowmelt peak timing, for all watersheds. Since a large portion of the runoff-producing regions in the western United States is snowmelt-dependent, this has large implications for the prediction of the amount and timing of streamflow in the coming century. This paper shows that hydrologic model parameterizations that give similar adequate calibration metrics can lead to statistically significant differences in hydrologic projections under climate change. Therefore, researchers and water resource managers should account for this uncertainty by assembling ensemble projections from both multiple parameter sets and GCMs.

Ficklin, Darren L.; Barnhart, Bradley L.

2014-11-01

238

Integration of a timeseries of remote sensing derived sub-pixel impervious maps into hydrological rainfall-runoff modelling  

Microsoft Academic Search

Hydrological models are indispensable to describe and study hydrological conditions in catchments. In case of fully distributed hydrological models there is a need for spatially distributed input data, which is often difficult and\\/or expensive to collect. Remote sensing potentially offers a relatively easy and cheap way of collecting spatially distributed information of the earth surface. Within the framework of the

B. Verbeiren; T. van de Voorde; F. Canters; O. Batelaan

2009-01-01

239

Hydrological modelling of a small catchment using SWAT-2000 Ensuring correct flow partitioning for contaminant modelling  

NASA Astrophysics Data System (ADS)

SummaryThe performance of the SWAT-2000 model was evaluated using stream flow at the outlet of the 142 ha Colworth catchment (Bedfordshire, UK). This catchment has been monitored since October 1999. The soil type consists of clay loam soil over stony calcareous clay and a rotation of wheat, oil seed rape, grass, beans and peas is grown. Much of the catchment is tile drained. Acceptable performance in hydrological modelling, along with correct simulation of the processes driving the water balance were essential first requirements for predicting contaminant transport. Initial results from SWAT-2000 identified some necessary modifications in the model source code for correct simulation of processes driving water balance. After modification of the code, hydrological simulation, crop growth and evapotranspiration (ET) patterns were realistic when compared with empirical data. Acceptable model performance (based on a number of error measures) was obtained in final model runs, with reasonable runoff partitioning into overland flow, tile drainage and base flow.

Kannan, N.; White, S. M.; Worrall, F.; Whelan, M. J.

2007-02-01

240

Hydrologic modeling using triangulated irregular networks : terrain representation, flood forecasting and catchment response  

E-print Network

Numerical models are modern tools for capturing the spatial and temporal variability in the land-surface hydrologic response to rainfall and understanding the physical relations between internal watershed processes and ...

Vivoni, Enrique R. (Enrique Rafael), 1975-

2003-01-01

241

Image use in the characterization of field parameters: incorporation of remote sensing with hydrologic simulation modeling  

E-print Network

The incorporation of hydrologic/crop growth models and remote sensing could lead to the development of improved precision farming systems. This research focused on strategies for incorporating these two individual devices. The first objective...

Fox, Garey Alton

2012-06-07

242

Investigations of Sensitivity and Uncertainty in Some Hydrologic Models of Yucca Mountain and Vicinity.  

National Technical Information Service (NTIS)

The uncertainty in travel time for water through unsaturated and saturated zones of Yucca Mountain and vicinity was determined by considering uncertainty associated with input parameters to the hydrologic models of these zones. A first-order analysis was ...

E. A. Jacobson, M. D. Freshley, F. H. Dove

1985-01-01

243

APPLICATION OF SWAT HYDROLOGIC MODEL FOR TMDL DEVELOPMENT ON CHAPEL BRANCH CREEK WATERSHED, SC  

Microsoft Academic Search

Watershed-scale hydrologic\\/water quality models are frequently used to characterize flow dynamics, pathways, and pollutant loading rates as a function of land use, soils, topography, management practices, and their interactions with variability in climate. SWAT (Soil and Water Assessment Tool) is a widely used GIS-based basin scale model to quantify the impact of land management practices on hydrology and water quality

D. M. Amatya; T. M. Williams; A. E. Edwards; N. S. Levine; D. R. Hitchcock

244

Land surface hydrology parameterization for atmospheric general circulation models including subgrid scale spatial variability  

NASA Technical Reports Server (NTRS)

Parameterizations are developed for the representation of subgrid hydrologic processes in atmospheric general circulation models. Reasonable a priori probability density functions of the spatial variability of soil moisture and of precipitation are introduced. These are used in conjunction with the deterministic equations describing basic soil moisture physics to derive expressions for the hydrologic processes that include subgrid scale variation in parameters. The major model sensitivities to soil type and to climatic forcing are explored.

Entekhabi, D.; Eagleson, P. S.

1989-01-01

245

Numerical prediction of subsidence with coupled geomechanical-hydrological modeling  

SciTech Connect

A coupled finite element geomechanical-hydrology code is currently under development for application to the problem of predicting groundwater disturbances associated with mine subsidence. The structural-fluid coupling is addressed by calculating the subsided mine geometry, with emphasis placed on determining the strata disturbance and locating damaged regions, for input into a hydrology code, which determines localized volume flow rates and aquifer fluctuations. Benefits from coupling will be best realized when field measurements, an additional aspect of the study concurrent with analytical investigations, indicating the relationship between increasing rock strain and increasing permeability are incorporated into hydraulic material descriptions. Hydrologic and structural calculations are presented to demonstrate computational capabilities applicable to mine subsidence.

Girrens, S.P.; Anderson, C.A.; Bennett, J.G.; Kramer, M.

1981-01-01

246

eWaterCycle: Developing a hyper resolution global hydrological model  

NASA Astrophysics Data System (ADS)

The development of a high resolution global hydrological model has recently been put forward as Grand Challenge for the hydrological community (Wood et al., 2011). The current version of the global hydrological model PCR-GLOBWB (van Beek et al., 2011) runs at a relatively coarse spatial grid (i.e. 0.1° or about 10 km at the equator), which is well above the hyper resolution envisioned in the Grand Challenge (i.e. 100 m). The eWaterCycle project aims at developing a high resolution global hydrological model allowing for a better representation of the effects of spatial heterogeneity in topography, soil, and vegetation on hydrological dynamics. Here we modify PCR-GLOBWB so that it runs at much higher resolution, on the order of 1 km or finer, that will be relevant for addressing critical water cycle science questions and many hydrological applications such as assessing water resources sustainability, flood and drought frequency under climate change. The development of such a hyper resolution model requires utilizing recent computational advances and massive parallel computer systems. So far, the hydrological community has not yet made full use of such possibilities. The eWaterCycle is a close cooperation between hydrologists (Delft University of Technology and Utrecht University) and the Netherlands eScience Center (NleSC) - that intends to supports and reinforce data-intensive research through creative and innovative use of information and communication technology (ICT). The hyper resolution model built in this project will contribute to the current scientific state-of-the-art by combining hydrological knowledge with ICT challenges. The refinement of the current model would be a huge step forward, because increasing resolution also requires adding an explicit spatial representation of local processes (groundwater flow, water diversions, glaciers, etc.) that will greatly enhance the regional to local applicability of global models. We also argue that the result envisions a qualitative jump in the quality of existing hydrological models. The scientific community will benefit in the field of hydrology, as well as in the fields of ICT and mathematics. As the results will be shared, the novel hydrological model will be available for other researchers and other organizations in order to elaborate further and to enrich and extend the model.

Sutanudjaja, Edwin; Hut, Rolf; Drost, Niels; Steele-Dunne, Susan; de Jong, Kor; van Beek, Ludovicus; Karssenberg, Derek; van de Giesen, Nick; Bierkens, Marc

2013-04-01

247

A simple hydrologically based model of land surface water and energy fluxes for general circulation models  

NASA Technical Reports Server (NTRS)

A generalization of the single soil layer variable infiltration capacity (VIC) land surface hydrological model previously implemented in the Geophysical Fluid Dynamics Laboratory (GFDL) general circulation model (GCM) is described. The new model is comprised of a two-layer characterization of the soil column, and uses an aerodynamic representation of the latent and sensible heat fluxes at the land surface. The infiltration algorithm for the upper layer is essentially the same as for the single layer VIC model, while the lower layer drainage formulation is of the form previously implemented in the Max-Planck-Institut GCM. The model partitions the area of interest (e.g., grid cell) into multiple land surface cover types; for each land cover type the fraction of roots in the upper and lower zone is specified. Evapotranspiration consists of three components: canopy evaporation, evaporation from bare soils, and transpiration, which is represented using a canopy and architectural resistance formulation. Once the latent heat flux has been computed, the surface energy balance is iterated to solve for the land surface temperature at each time step. The model was tested using long-term hydrologic and climatological data for Kings Creek, Kansas to estimate and validate the hydrological parameters, and surface flux data from three First International Satellite Land Surface Climatology Project Field Experiment (FIFE) intensive field campaigns in the summer-fall of 1987 to validate the surface energy fluxes.

Liang, XU; Lettenmaier, Dennis P.; Wood, Eric F.; Burges, Stephen J.

1994-01-01

248

Comparison between fully distributed model and semi-distributed model in urban hydrology modeling  

NASA Astrophysics Data System (ADS)

Water management in urban areas is becoming more and more complex, especially because of a rapid increase of impervious areas. There will also possibly be an increase of extreme precipitation due to climate change. The aims of the devices implemented to handle the large amount of water generate by urban areas such as storm water retention basins are usually twofold: ensure pluvial flood protection and water depollution. These two aims imply opposite management strategies. To optimize the use of these devices there is a need to implement urban hydrological models and improve fine-scale rainfall estimation, which is the most significant input. In this paper we suggest to compare two models and their sensitivity to small-scale rainfall variability on a 2.15 km2 urban area located in the County of Val-de-Marne (South-East of Paris, France). The average impervious coefficient is approximately 34%. In this work two types of models are used. The first one is CANOE which is semi-distributed. Such models are widely used by practitioners for urban hydrology modeling and urban water management. Indeed, they are easily configurable and the computation time is reduced, but these models do not take fully into account either the variability of the physical properties or the variability of the precipitations. An alternative is to use distributed models that are harder to configure and require a greater computation time, but they enable a deeper analysis (especially at small scales and upstream) of the processes at stake. We used the Multi-Hydro fully distributed model developed at the Ecole des Ponts ParisTech. It is an interacting core between open source software packages, each of them representing a portion of the water cycle in urban environment. Four heavy rainfall events that occurred between 2009 and 2011 are analyzed. The data comes from the Météo-France radar mosaic and the resolution is 1 km in space and 5 min in time. The closest radar of the Météo-France network is a C-band one located at 37 km West. In this work we compare the hydrological response of two models for the 4 rainfall events first with the available radar data. Then a particular focus is made on the impact of small-scale unmeasured rainfall variability (i.e. occurring at scales below the available one). More precisely scaling properties of rainfall are used to generate an ensemble of downscaled rainfall fields (simply by continuing the underlying cascade process whose relevant parameters are estimated on the available range of scales). An ensemble of hydrological responses is then simulated, and the variability within it analyzed. It appears that the associated uncertainty is significant and should be taken into account. Finally we will discuss the interest of deploying X-band radars (which provide an hectometric resolution) in urban environment and the potential benefits of using these models and small-scale rainfall data for the management of sewerage and retentions basin. Further analysis on these issues will be carried out next year with the installation of an X-band radar near Marne-la-Vallée (located at roughly 10 Km of the studied catchment) in the framework of the RainGain project (European project financed by the Interreg IVB funds).

Ichiba, Abdellah; Gires, Auguste; Giangola-Murzyn, Agathe; Tchiguirinskaia, Ioulia; Schertzer, Daniel; Bompard, Philippe

2013-04-01

249

High performance computing (HPC) based hydrological modelling framework to support complex model-coupling and uncertainty studies  

NASA Astrophysics Data System (ADS)

We have recently initiated a framework of HPC based hydrological modelling system that intends to couple hydrological model and numerical weather prediction on a unified platform. The framework is intended to achieve 1) seamlessly coupling of the hydrological models with the climate/numerical weather models that are supported by the same HPC platform; 2) supporting large-scale hydrological modelling in greater details; 3) conducting joint ensemble runs of coupled modelling systems so as to account for the modelling uncertainty; 4) supporting multi-model ensembles to identify potential extreme storms with certain climate projections; 5) the ability of processing large volume of data (terabyte level). At current stage, we are focusing on the design and implementation of a versatile interface between the two backend NWPs (Unified Model from UK Met Office & WRF from NCAR) to a number of preferred hydrological models. The expected outcome will serve well the research community and practitioners in terms of providing an easy-access modelling platform as well as providing benchmarking datasets from tailor-made experiments. Keywords: Coupled models, Hydrological modelling, High Performance Computing, Unified Model, WRF, Multi-model ensembles

Xuan, Yunqing; Zhu, Dehua

2014-05-01

250

Marrying Hydrological Modelling and Integrated Assessment for the needs of Water Resource Management  

NASA Astrophysics Data System (ADS)

This paper discusses the integration of hydrology with other disciplines using an Integrated Assessment (IA) and modelling approach to the management and allocation of water resources. Recent developments in the field of socio-hydrology aim to develop stronger relationships between hydrology and the human dimensions of Water Resource Management (WRM). This should build on an existing wealth of knowledge and experience of coupled human-water systems. To further strengthen this relationship and contribute to this broad body of knowledge, we propose a strong and durable "marriage" between IA and hydrology. The foundation of this marriage requires engagement with appropriate concepts, model structures, scales of analyses, performance evaluation and communication - and the associated tools and models that are needed for pragmatic deployment or operation. To gain insight into how this can be achieved, an IA case study in water allocation in the Lower Namoi catchment, NSW, Australia is presented.

Croke, B. F. W.; Blakers, R. S.; El Sawah, S.; Fu, B.; Guillaume, J. H. A.; Kelly, R. A.; Patrick, M. J.; Ross, A.; Ticehurst, J.; Barthel, R.; Jakeman, A. J.

2014-09-01

251

A method for coupling a parameterization of the planetary boundary layer with a hydrologic model  

NASA Technical Reports Server (NTRS)

Deardorff's parameterization of the planetary boundary layer is adapted to drive a hydrologic model. The method converts the atmospheric conditions measured at the anemometer height at one site to the mean values in the planetary boundary layer; it then uses the planetary boundary layer parameterization and the hydrologic variables to calculate the fluxes of momentum, heat and moisture at the atmosphere-land interface for a different site. A simplified hydrologic model is used for a simulation study of soil moisture and ground temperature on three different land surface covers. The results indicate that this method can be used to drive a spatially distributed hydrologic model by using observed data available at a meteorological station located on or nearby the site.

Lin, J. D.; Sun, Shu Fen

1986-01-01

252

Improved ground hydrology calculations for global climate models (GCMs) - Soil water movement and evapotranspiration  

NASA Technical Reports Server (NTRS)

A physically based ground hydrology model is presented that includes the processes of transpiration, evaporation from intercepted precipitation and dew, evaporation from bare soil, infiltration, soil water flow, and runoff. Data from the Goddard Institute for Space Studies GCM were used as inputs for off-line tests of the model in four 8 x 10 deg regions, including Brazil, Sahel, Sahara, and India. Soil and vegetation input parameters were caculated as area-weighted means over the 8 x 10 deg gridbox; the resulting hydrological quantities were compared to ground hydrology model calculations performed on the 1 x 1 deg cells which comprise the 8 x 10 deg gridbox. Results show that the compositing procedure worked well except in the Sahel, where low soil water levels and a heterogeneous land surface produce high variability in hydrological quantities; for that region, a resolution better than 8 x 10 deg is needed.

Abramopoulos, F.; Rosenzweig, C.; Choudhury, B.

1988-01-01

253

Coupling socio-economic factors and eco-hydrological processes using a cascade-modeling approach  

NASA Astrophysics Data System (ADS)

Most hydrological studies do not account for the socio-economic influences on eco-hydrological processes. However, socio-economic developments often change the water balance substantially and are highly relevant in understanding changes in hydrological responses. In this study a multi-disciplinary approach was used to study the cascading impacts of socio-economic drivers of land use and land cover (LULC) changes on the eco-hydrological regime of the Lake Naivasha Basin. The basin has recently experienced substantial LULC changes exacerbated by socio-economic drivers. The simplified cascade models provided insights for an improved understanding of the socio-ecohydrological system. Results show that the upstream population has transformed LULC such that runoff during the period 1986-2010 was 32% higher than during the period 1961-1985. Cut-flower export volumes and downstream population growth explain 71% of the water abstracted from Lake Naivasha. The influence of upstream population on LULC and upstream hydrological processes explained 59% and 30% of the variance in lake storage volumes and sediment yield respectively. The downstream LULC changes had significant impact on large wild herbivore mammal species on the fringe zone of the lake. This study shows that, in cases where observed socio-economic developments are substantial, the use of a cascade-modeling approach, that couple socio-economic factors to eco-hydrological processes, can greatly improve our understanding of the eco-hydrological processes of a catchment.

Odongo, V. O.; Mulatu, D. W.; Muthoni, F. K.; van Oel, P. R.; Meins, F. M.; van der Tol, C.; Skidmore, A. K.; Groen, T. A.; Becht, R.; Onyando, J. O.; van der Veen, A.

2014-10-01

254

Modeling the effect of glacier recession on streamflow response using a coupled glacio-hydrological model  

SciTech Connect

We describe an integrated spatially distributed hydrologic and glacier dynamic model, and use it to investigate the effect of glacier recession on streamflow variations for the Upper Bow River basin, a tributary of the South Saskatchewan River. Several recent studies have suggested that observed decreases in summer flows in the South Saskatchewan River are partly due to the retreat of glaciers in the river's headwaters. Modeling the effect of glacier changes on streamflow response in river basins such as the South Saskatchewan is complicated due to the inability of most existing physically-based distributed hydrologic models to represent glacier dynamics. We compare predicted variations in glacier extent, snow water equivalent and streamflow discharge made with the integrated model with satellite estimates of glacier area and terminus position, observed streamflow and snow water equivalent measurements over the period of 1980 2007. Simulations with the coupled hydrology-glacier model reduce the uncertainty in streamflow predictions. Our results suggested that on average, the glacier melt contribution to the Bow River flow upstream of Lake Louise is about 30% in summer. For warm and dry years, however, the glacier melt contribution can be as large as 50% in August, whereas for cold years, it can be as small as 20% and the timing of glacier melt signature can be delayed by a month.

Naz, Bibi S [ORNL] [ORNL; Frans, Chris [University of Washington, Seattle] [University of Washington, Seattle; Clarke, Garry [University of British Columbia, Vancouver] [University of British Columbia, Vancouver; Burns, [Watershed Sciences Inc. (WSI), Portland] [Watershed Sciences Inc. (WSI), Portland; Lettenmaier, Dennis [University of Washington, Seattle] [University of Washington, Seattle

2014-01-01

255

Modeling the effect of glacier recession on streamflow response using a coupled glacio-hydrological model  

NASA Astrophysics Data System (ADS)

We describe an integrated spatially distributed hydrologic and glacier dynamic model, and use it to investigate the effect of glacier recession on streamflow variations for the Upper Bow River basin, a tributary of the South Saskatchewan River. Several recent studies have suggested that observed decreases in summer flows in the South Saskatchewan River are partly due to the retreat of glaciers in the river's headwaters. Modeling the effect of glacier changes on streamflow response in river basins such as the South Saskatchewan is complicated due to the inability of most existing physically-based distributed hydrologic models to represent glacier dynamics. We compare predicted variations in glacier extent, snow water equivalent and streamflow discharge made with the integrated model with satellite estimates of glacier area and terminus position, observed streamflow and snow water equivalent measurements over the period of 1980-2007. Simulations with the coupled hydrology-glacier model reduce the uncertainty in streamflow predictions. Our results suggested that on average, the glacier melt contribution to the Bow River flow upstream of Lake Louise is about 30% in summer. For warm and dry years, however, the glacier melt contribution can be as large as 50% in August, whereas for cold years, it can be as small as 20% and the timing of glacier melt signature can be delayed by a month.

Naz, B. S.; Frans, C. D.; Clarke, G. K. C.; Burns, P.; Lettenmaier, D. P.

2013-04-01

256

Modeling the effect of glacier recession on streamflow response using a coupled glacio-hydrological model  

NASA Astrophysics Data System (ADS)

We describe an integrated spatially distributed hydrologic and glacier dynamic model, and use it to investigate the effect of glacier recession on streamflow variations for the upper Bow River basin, a tributary of the South Saskatchewan River, Alberta, Canada. Several recent studies have suggested that observed decreases in summer flows in the South Saskatchewan River are partly due to the retreat of glaciers in the river's headwaters. Modeling the effect of glacier changes on streamflow response in river basins such as the South Saskatchewan is complicated due to the inability of most existing physically based distributed hydrologic models to represent glacier dynamics. We compare predicted variations in glacier extent, snow water equivalent (SWE), and streamflow discharge with satellite estimates of glacier area and terminus position, observed glacier mass balance, observed streamflow and snow water-equivalent measurements, respectively over the period of 1980-2007. Observations of multiple hydroclimatic variables compare well with those simulated with the coupled hydrology-glacier model. Our results suggest that, on average, the glacier melt contribution to the Bow River flow upstream of Lake Louise is approximately 22% in summer. For warm and dry years, however, the glacier melt contribution can be as large as 47% in August, whereas for cold years, it can be as small as 15% and the timing of the glacier melt signature can be delayed by a month. The development of this modeling approach sets the stage for future predictions of the influence of warming climate on streamflow in partially glacierized watersheds.

Naz, B. S.; Frans, C. D.; Clarke, G. K. C.; Burns, P.; Lettenmaier, D. P.

2014-02-01

257

Development of An Integrated Hydrologic Model in Yolo County, California  

NASA Astrophysics Data System (ADS)

To more efficiently use the Cache Creek flows and the groundwater basin as the sources of water supply and to restore the riparian ecosystem along the Cache Creek, Yolo County Flood Control and Water Conservation District (YCFCWCD) in Woodland, California plans to conduct the Cache Creek Groundwater Recharge and Recovery Program (CCGRRP). The concept of this program is to operate the groundwater basin to induce greater amounts of groundwater recharge from Cache Creek directly along the creek and to increase the recharge even further by diverting rainy season water at the District's Capay Diversion Dam into the West Adams Canal to a few recharge basins outside the active channel of Cache Creek. Besides the CCGRRP, cities of Woodland and Davis are in the process of conducting groundwater management plans, and the stakeholders in Yolo County developing a long-term integrated regional water management plan (IRWMP) for the entire county. To effectively evaluate the benefits and impacts of CCGRRP, local groundwater management plans, and the Yolo County IRWMP, the Integrated Groundwater and Surface water Model (IGSM) was applied to the Yolo groundwater basin. The IGSM is a comprehensive integrated hydrologic model that simulates both surface water and groundwater flow systems, including rainfall-runoff, soil moisture accounting and unsaturated flow, crop consumptive module, stream-aquifer interaction, and groundwater flow. The finite element code was originally developed in 1990 for the California Department of Water Resources and the State Water Resources Control Board. The IGSM code has subsequently been applied to more than 25 groundwater basins in California and other states. The model code has been peer reviewed and upgraded throughout its application to various projects, with the latest upgrade in 2004, as part of the application to the Stony Creek Fan area of Sacramento Valley. The Yolo County IGSM (YCIGSM) was calibrated against the historical (1970-2000) groundwater level records at 105 monitoring wells, and three streamflow gages along Cache Creek. Calibration results show that the YCIGSM is able to reasonably simulate the long-term groundwater level trends and short-term seasonal fluctuations. The YCIGSM will be used to develop operational guidelines to manage the groundwater basin, to determine the optimum yield of water projects, to identify benefits and impacts of projects on existing groundwater users, and to assess the environmental benefits and impacts during the development of projects, as well as during the environmental permitting process.

Liang, Y.; Taghavi, A.; Stevenson, M.; Najmus, S.

2006-12-01

258

Rainfall-Runoff Modeling to Compare Hydrological Processes Governing Solute Transport in Five Different Agricultural Watersheds  

NASA Astrophysics Data System (ADS)

Non-point sources of fertilizers and pesticides from agricultural areas can impair the water quality of streams. A better understanding of how hydrological processes affect the transport of agricultural chemicals to streams is required to improve management of fresh water resources. Examining how hydrological processes vary in agricultural landscapes and subsequently affect solute transport is a focus of the U.S. Geological Survey's (USGS) National Water Quality Assessment (NAWQA) Program. As part of the NAWQA Program, the quantities of precipitation, irrigation, recharge, ground water, seepage and streamflow are being monitored along with reported application rates of agricultural chemicals within five agricultural watersheds in California, Washington, Nebraska, Indiana, and Maryland. Two quasi-distributed hydrological models capable of simulating solute transport (the Soil and Water Assessment Tool (SWAT) and the Water, Energy, Biogeochemical Model (WEBMOD)) were applied to each watershed. Although the underlying environmental processes were represented differently in each model, both models were capable of simulating the expected hydrological characteristics and dominant flow paths in each watershed. In each model, the relative contributions of infiltration-excess overland flow, saturation-excess overland flow, shallow subsurface flow, preferential flow, and deep ground water flow were estimated. These fluxes then were compared to measured in-stream solute concentrations to assess how each hydrological flow path affected water quality. Generally, soil profile characteristics, land management practices, and irrigation methods regulated hydrological connections between watershed hillslopes and receiving streams.

Linard, J. I.; Webb, R. M.; Wieczorek, M. E.; Wolock, D. M.

2004-12-01

259

Modelling hydrological responses of Nerbioi River Basin to Climate Change  

Microsoft Academic Search

Future climate change will affect aquatic systems on various pathways. Regarding the hydrological cycle, which is a very important pathway, changes in hydrometeorological variables (air temperature, precipitation, evapotranspiration) in first order impact discharges. The fourth report assessment of the Intergovernmental Panel for Climate Change indicates there is evidence that the recent warming of the climate system would result in more

Maddalen Mendizabal; Roberto Moncho; Guillem Chust; Peter Torp

2010-01-01

260

Digital terrain modeling applications in surface mining hydrology  

Microsoft Academic Search

In the Eastern Appalachian Region unique problems are created by the rugged mountainous terrain, necessitating contour mining or mountain top removal mining practices that leave the terrain highly modified. These activities result in a major disruption of the antecedent hydrologic and hydraulic conditions. Infiltration rates, overland flow paths, subsurface flow paths, soils and cover conditions are all modified. No existing

R. N. Eli; B. L. Palmer; R. L. Hamric

1980-01-01

261

Remote Sensing Data and Information for Hydrological Monitoring and Modeling  

E-print Network

remote sensing sensors are carried out using visible (VIS), infrared (IR) and microwave (MW) wavelengths are typically sparse. Remote sensing technology used electromagnetic spectrum in the range of wavelengths to 100 cm, visible, infrared and microwave spectrum is commonly used in retrieval of hydrological

Krakauer, Nir Y.

262

Data Mining for Generating Predictive Models of Local Hydrology  

Microsoft Academic Search

The problem of downscaling the effects of global scale climate variability into predictions of local hydrology has important implications for water resource management. Our research aims to identify predictive relationships that can be used to integrate solar and ocean-atmospheric conditions into forecasts of regional water flows. In recent work we have developed an induction technique called second-order table compression, in

Rattikorn Hewett

2003-01-01

263

Hydrological storage variations in a lake water balance, observed from multi-sensor satellite data and hydrological models.  

NASA Astrophysics Data System (ADS)

Freshwater lakes and reservoirs account for 74.5% of continental water storage in surface water bodies and only 1.8% resides in rivers. Lakes and reservoirs are a key component of the continental hydrological cycle but in-situ monitoring networks are very limited either because of sparse spatial distribution of gauges or national data policy. Monitoring and predicting extreme events is very challenging in that case. In this study we demonstrate the use of optical remote sensing, satellite altimetry and the GRACE gravity field mission to monitor the lake water storage variations in the Aral Sea. Aral Sea is one of the most unfortunate examples of a large anthropogenic catastrophe. The 4th largest lake of 1960s has been decertified for more than 75% of its area due to the diversion of its primary rivers for irrigation purposes. Our study is focused on the time frame of the GRACE mission; therefore we consider changes from 2002 onwards. Continuous monthly time series of water masks from Landsat satellite data and water level from altimetry missions were derived. Monthly volumetric variations of the lake water storage were computed by intersecting a digital elevation model of the lake with respective water mask and altimetry water level. With this approach we obtained volume from two independent remote sensing methods to reduce the error in the estimated volume through least square adjustment. The resultant variations were then compared with mass variability observed by GRACE. In addition, GARCE estimates of water storage variations were compared with simulation results of the Water Gap Hydrology Model (WGHM). The different observations from all missions agree that the lake reached an absolute minimum in autumn 2009. A marked reversal of the negative trend occured in 2010 but water storage in the lake decreased again afterwards. The results reveal that water storage variations in the Aral Sea are indeed the principal, but not the only contributor to the GRACE signal of mass variations in this region; this is also verified by WGHM simulations. An important implication of this finding is the possibility of GRACE to analyses storage changes in other hydrological compartments (soil moisture, snow and groundwater) once the signal has been reduced for surface water storage changes. Therefore the congruent use of multi-sensor satellite data for hydrological studies proves to be a great source of information for assessing terrestrial water storage variations.

Singh, Alka; Seitz, Florian; Schwatke, Christian; Guentner, Andreas

2013-04-01

264

Climate change impact on available water resources obtained using multiple global climate and hydrology models  

NASA Astrophysics Data System (ADS)

Climate change is expected to alter the hydrological cycle resulting in large-scale impacts on water availability. However, future climate change impact assessments are highly uncertain. For the first time, multiple global climate (three) and hydrological models (eight) were used to systematically assess the hydrological response to climate change and project the future state of global water resources. The results show a large spread in projected changes in water resources within the climate-hydrology modelling chain for some regions. They clearly demonstrate that climate models are not the only source of uncertainty for hydrological change. But there are also areas showing a robust change signal, such as at high latitudes and in some mid-latitude regions, where the models agree on the sign of projected hydrological changes, indicative of higher confidence. In many catchments an increase of available water resources is expected but there are some severe decreases in central and Southern Europe, the Middle East, the Mississippi river basin, Southern Africa, Southern China and south eastern Australia.

Hagemann, Stefan; Chen, Cui; Clark, Douglas B.; Folwell, Sonja; Gosling, Simon N.; Haddeland, Ingjerd; Hanasaki, Naota; Heinke, Jens; Ludwig, Fulco; Voss, Frank; Wiltshire, Andrew J.

2013-04-01

265

Climate change impact on available water resources obtained using multiple global climate and hydrology models  

NASA Astrophysics Data System (ADS)

Climate change is expected to alter the hydrological cycle resulting in large-scale impacts on water availability. However, future climate change impact assessments are highly uncertain. For the first time, multiple global climate (three) and hydrological models (eight) were used to systematically assess the hydrological response to climate change and project the future state of global water resources. The results show a large spread in projected changes in water resources within the climate-hydrology modelling chain for some regions. They clearly demonstrate that climate models are not the only source of uncertainty for hydrological change. But there are also areas showing a robust change signal, such as at high latitudes and in some mid-latitude regions, where the models agree on the sign of projected hydrological changes, indicative of higher confidence. In many catchments an increase of available water resources is expected but there are some severe decreases in central and Southern Europe, the Middle East, the Mississippi river basin, Southern Africa, Southern China and south eastern Australia.

Hagemann, S.; Chen, C.; Clark, D. B.; Folwell, S.; Gosling, S. N.; Haddeland, I.; Hanasaki, N.; Heinke, J.; Ludwig, F.; Voß, F.; Wiltshire, A. J.

2012-12-01

266

Evaluating the SWAT Model for Hydrological Modeling in the Xixian Watershed and A Comparison with the XAJ Model  

SciTech Connect

Already declining water availability in Huaihe River, the 6th largest river in China, is further stressed by climate change and intense human activities. There is a pressing need for a watershed model to better understand the interaction between land use activities and hydrologic processes and to support sustainable water use planning. In this study, we evaluated the performance of SWAT for hydrologic modeling in the Xixian River Basin, located at the headwaters of the Huaihe River, and compared its performance with the Xinanjiang (XAJ) model that has been widely used in China

Shi, Peng; Chen, Chao; Srinivasan, Raghavan; Zhang, Xuesong; Cai, Tao; Fang, Xiuqin; Qu, Simin; Chen, Xi; Li, Qiongfang

2011-09-10

267

Definition of Hydrologic Response Units in Depression Plagued Digital Elevation Models  

NASA Astrophysics Data System (ADS)

Definition of hydrologic response units using digital elevation models (DEMs) is sensitive to the occurrence of topographic depressions. Real depressions can be important to the hydrology and biogeochemistry a catchment, often coinciding with areas of surface saturation. Artifact depressions, in contrast, result in digital "black holes", artificially truncating the hydrologic flow lengths and altering hydrologic flow directions, parameters that are often used in defining hydrologic response units. Artifact depressions must be removed from DEMs prior to definition of hydrologic response units. Depression filling or depression trenching techniques can be used to remove these artifacts. Depression trenching methods are often considered more appropriate because they preserve the topographic variability within a depression thus avoiding the creation of spurious flat areas. Current trenching algorithms are relatively slow and unable to process very large or noisy DEMs. A new trenching algorithm that overcomes these limitations is described. The algorithm does not require finding depression catchments or outlets, nor does it need special handling for nested depressions. Therefore, artifacts can be removed from large or noisy DEMs efficiently, while minimizing the number of grid elevations requiring modification. The resulting trench is a monotonically descending path starting from the lowest point in a depression, passing through the depression's outlet, and ending at a point of lower elevation outside the depression. The importance of removing artifact depressions is demonstrated by showing hydrologic response units both before and after the removal of artifact depressions from the DEM.

Lindsay, J. B.; Creed, I. F.

2002-12-01

268

Further testing of the integrated hydrology model (InHM): multiple-species sediment transport  

Microsoft Academic Search

The sediment-transport version of the Integrated Hydrology Model (InHM) is further tested for the case of multiple-species sediment transport with both rainsplash and hydraulic erosion using data from the Johansen et al. (2001) field experiments. The ability to simulate sub-plot scale interactions between surface water hydrology and multiple-species sediment transport with InHM is clearly demonstrated. Sensitivity analysis reveals that the

Qihua Ran; Christopher S. Heppner; Joel E. VanderKwaak; Keith Loague

2007-01-01

269

The Temporal Variability of Soil Moisture and Surface Hydrological Quantities in a Climate Model  

Microsoft Academic Search

The variance budget of land surface hydrological quantities is analyzed in the second Atmospheric Model Intercomparison Project (AMIP2) simulation made with the Canadian Centre for Climate Modelling and Analysis (CCCma) third-generation general circulation model (AGCM3). The land surface parameteriza- tion in this model is the comparatively sophisticated Canadian Land Surface Scheme (CLASS). Second- order statistics, namely variances and covariances, are

Vivek K. Arora; George J. Boer

2006-01-01

270

Issues of experimental design for comparing the performance of hydrologic models  

Microsoft Academic Search

Research to compare the performance of precipitation-runoff models (and indeed models of other hydrologic and geophysical processes) is increasingly reported in the literature. A characteristic of almost all such intercomparisons at present is that each model is tested only by the research group (the “operator”) that has developed it, so that differences between models are confounded with differences between operators.

Robin T. Clarke

2008-01-01

271

Development and application of a storage-release based distributed hydrologic model using GIS  

NASA Astrophysics Data System (ADS)

SummaryThe objective of this paper is to present the development and application of a grid based hydrologic model using an object oriented framework within geographic information systems (GIS). The proposed model is called Storage Released based Distributed Hydrologic Model (STORE DHM). Development of STORE DHM is a part of a broader objective to develop a modular hydrologic modeling system within GIS. In this paper, the conceptual framework of STORE DHM including its application to three watersheds in Indiana is presented. The model is tested in the study watersheds by first calibrating it against observed flow hydrograph for a single event, and then verifying it for three additional storm events using both point (gauged) and continuous (radar) rainfall data. Results show that SOTRE DHM is able to predict runoff hydrographs for different types of events in terms of storm duration, peak flow magnitude and time-to-peak. The average Nash-Sutcliffe coefficient is greater than 0.8 for all runoff hydrograph during validation, and the errors in peak flow and time-to-peak predictions are within 5% and 15%, respectively. In addition, STORE DHM output is compared with outputs from two hydrologic models including Hydrologic Engineering Center's Hydrologic Modeling System (HEC-HMS) and time variant Spatially Distributed Direct Hydrograph travel time method (SDDH). Results from these comparisons show that STORE DHM outperforms both HEC-HMS and SDDH in terms of overall hydrograph shape and flow magnitude. Although the results from application of STORE DHM are encouraging, the work presented in this paper is just an initial step towards developing a comprehensive tightly coupled GIS modeling framework for hydrology.

Kang, Kwangmin; Merwade, Venkatesh

2011-06-01

272

Ensemble Kalman Filter Data Assimilation for the ParFlow Hydrologic Model  

NASA Astrophysics Data System (ADS)

Research in hydrometeorology has demonstrated repeatedly that atmospheric models benefit from detailed formulations of the land surface, and that energy and moisture fluxes between the land surface and atmosphere are coupled strongly not only with atmospheric conditions, but also with subsurface hydrology—particularly soil moisture distribution. Improving the representation of hydrologic processes should lead to better predictive skill in a fully-coupled weather forecasting model, and the hydrologic model itself can be improved by incorporating observed data values. For this work, we apply the Ensemble Kalman Filter functionality included in the Data Assimilation Assimilation Research Testbed (DART), a collection of data assimilation tools maintained at the National Center for Atmospheric Research, to the ParFlow hydrologic model—the hydrologic component of the TerrSysMP fully coupled hydrologic - land surface - atmospheric model system. This generalized data assimilation tool allows observations of variables in the hydrologic component of the system to be incorporated into the overall error covariance matrix thus guiding the development of quantities that define the model state. Single dimension column tests, two-dimensional hillslope tests, and a three-dimensional drainage and dry-out test were performed with the ParFlow-DART system to evaluate the effects of assimilating pressure head, soil moisture, and outflow observations on the development of the model through time. The success of these tests will allow the ParFlow-DART system to be developed into a complete data assimilation package for the TerrSysMP fully-coupled modeling system.

Williams, John

2014-05-01

273

Treatment of HBV-related cirrhosis.  

PubMed

The goal of antiviral therapy in HBV cirrhotic patients is to prevent progression of the disease to decompensated cirrhosis, end-stage liver disease, hepatocellular carcinoma and death. This goal can be achieved if HBV replication can be suppressed, leading to biochemical remission, histological improvement and prevention of complications. If finite treatment with pegylated interferon is not contraindicated in compensated cirrhosis, long-term treatment with nucleoside/nucleotide analogues is recommended in patients with HBV-related cirrhosis, especially in decompensated cirrhosis. Patients with cirrhosis require careful monitoring to detect resistance and prevent flares, and also to screen for hepatocellular carcinoma, portal hypertension and liver failure. PMID:19485793

Vallet-Pichard, Anais; Mallet, Vincent; Costentin, Charlotte E; Pol, Stanislas

2009-06-01

274

New insight into unstable hillslopes hydrology from hydrogeochemical modelling.  

NASA Astrophysics Data System (ADS)

In the black marl outcrops of the French South Alps, sub surface flow conditions are considered as the main triggering factor for initiation and reactivation of landslides. The problem is traditionally addressed in term of hydrological processes (how does percolation to the water table occur?) but in some cases the origin of water is also in question. Direct rainfall is generally assumed as the only water source for groundwater recharge in shallow hillslope aquifers. The bedrock is also supposed impervious and continuous. Yet the geological environment of the study area is very complex owing to the geological history of this alpine sector. The autochthonous callovo-oxfordian black marl bedrock is highly tectonized (Maquaire et al., 2003) and may be affected by large, possibly draining discontinuities. A deep water inflow at the slip surface may at least locally result in increase the pore pressure and decrease the effective shearing resistance of the landslide material. In the active slow-moving landslide of Super-Sauze (Malet and Maquaire, 2003), this question has been addressed using hydrochemical investigations. The groundwater was sampled during five field campaigns uniformly spread out over the year from a network of boreholes. Water chemistry data were completed by geochemical and mineralogical analyses of the marl material. The major hydro-geochemical processes over area proved (1) mixing processes, (2) pyrite alteration, (3) dissolution/precipitation of carbonates and (4) cations exchange (de Montety et al., 2007). A geochemical modelling was carried out using the model Phreeqc (Parkhurst and Appelo, version 2.15, 2008) to check how suitable was observed water chemistry with the reservoir characteristics. The modelling exercise was based on a kinetics approach of soil-water interactions. The model simulates the rock alteration by the dissolution of the primary minerals and the precipitation of new phases. Initial parameters were obtained from geochemical and mineralogical analyses or from the literature (kinetics constants). The simulations showed that pH, sulphate and calcium concentrations in groundwater could be reproduced from reasonable assumptions. However, the observed high concentrations in magnesium and sodium were not correctly simulated by the model. Furthermore, a particular anomaly in the Na+ concentration was observed in the most active part of the landslide. Lastly, isotopic investigation showed that groundwater 3H content in this sector was significantly lower than groundwater content in the other parts of the landslide and lower than the mean rainwater content. This result showed that the mean groundwater age in the active part was probably higher than elsewhere in the landslide. All these arguments led us to conclude that groundwater was locally recharged with saline waters from areas outside the watershed, coming up through the bedrock using major discontinuities. This assumption is in agreement with the geological context. de Montety, V., V. Marc, C. Emblanch, J.-P. Malet, C. Bertrand, O. Maquaire, and T. A. Bogaard, 2007, Identifying the origin of groundwater and flow processes in complex landslides affecting black marls: insights from a hydrochemical survey.: Earth Surface Processes and Landforms, v. 32, p. 32-48. Malet, J.-P. and Maquaire, O., 2003. Black marl earthflows mobility and long-term seasonal dynamic in southeastern France. In: Picarelli, L. (Ed). Proceedings of the International Conference on Fast Slope Movements: Prediction and Prevention for Risk Mitigation. Patron Editore, Bologna: 333-340. Maquaire, O., Malet, J.-P., Remaître, A., Locat, J., Klotz, S. and Guillon, J., 2003. Instability conditions of marly hillslopes: towards landsliding or gullying? The case of the Barcelonnette Bassin, South East France. Engineering Geology, 70(1-2): 109-130. Parkhurst, D.L. and Appelo, C.A.J., 1999, User's guide to PHREEQC (version 2)--A computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations: U.S. Geological Survey Water-Resources I

Bertrand, C.; Marc, V.; Malet, J.-P.

2010-05-01

275

Snow Hydrology Model Combined with Remotely Sensed Snow Observations in the Upper Helmand Watershed, Afghanistan (Invited)  

NASA Astrophysics Data System (ADS)

In many regions of the world snowmelt can be an important source of water resources. However, limited data availability can make water resources planning and management difficult, particularly in developing countries. For this study, a temperature index snow model in conjunction with a hydrologic model was used to analyze the snowpack and hydrology of the Upper Helmand Watershed in Afghanistan. Limited ground data and remotely sensed precipitation data were used to develop and force the model. The snow model was calibrated using high-resolution multispectral imagery of the snow covered area (SCA). The calibrated snow model was compared to passive microwave estimates of snow water equivalent (SWE). Finally the peak snowpack, derived using the passive microwave SWE data, was used to initialize the hydrologic model prior to melt onset. The model’s ability to simulate runoff was validated using reservoir measurements at the basin outlet. This study improved our understanding of the hydrologic processes in this remote, data-scarce region. In particular, the snow extent and mass as well as the contribution of snow to runoff are quantified with enhanced confidence by using both the model simulations and remotely sensed data. The temperature index snow model accurately simulates the snow accumulation and melt process as demonstrated in the temporal and spatial comparison to the high-resolution SCA imagery. Inflows to the reservoir were reasonably simulated using the hydrologic model, though the model exhibited sensitivity to input precipitation data. The passive microwave SWE data provided reasonable estimates of snow mass and distribution in the Upper Helmand Watershed, and has potential for initializing hydrological models to add value to water supply planning and dam management.

Vuyovich, C. M.; Jacobs, J. M.; Daly, S. F.; Scharffenberg, W.

2010-12-01

276

Regional Hydrological Modeling in Africa: Calibration and Performance Test of IBIS  

NASA Astrophysics Data System (ADS)

Freshwater availability is a particularly important issue in Africa where large portions of the continent are arid or semi-arid and the precipitation and runoff are highly variable. As part of a larger study we are using two numerical models the Integrated BIosphere Simulator (IBIS) and the Hydrological Routing Algorithm (HYDRA), to address the relative impacts of the three major determinants of the observed changes in terrestrial hydrology in Africa since 1950: (1) climate variability, (2) land use/land cover change, and (3) water management practices. IBIS simulates a wide range of processes, including land surface physics, surface and soil water balance, canopy physiology, vegetation phenology, terrestrial carbon balance and vegetation dynamics. While IBIS has been widely tested globally and regionally, the stand-alone hydrological performance for arid and semi-arid region has not been fully evaluated yet. In this study, the hydrology of IBIS was calibrated and tested against data from the HAPEX-SAHEL experiment and long-term discharge observations from the Lake Chad Basin. Firstly, we tested the simulated hydrological sensitivity to soil physical properties, vegetation types, and weather generation parameters -- all of these parameters have substantial impacts on the water balance. Secondly, parameters dictating the generation of weather in IBIS were adapted to the African climatic conditions. Thirdly, the original soil water infiltration model was enhanced with a Green-Ampt model, which significantly improved the hydrological simulation in arid and semi-arid African regions. Lastly, the hydrological performance of IBIS was tested against the observations in Africa, and the results show that with proper calibration IBIS satisfactorily simulates the large-scale hydrology of this region.

Li, K. Y.; Coe, M. T.; Ramankutty, N.

2003-04-01

277

Examination of Soil Moisture Retrieval Using SIR-C Radar Data and a Distributed Hydrological Model  

NASA Technical Reports Server (NTRS)

A major objective of soil moisture-related hydrological-research during NASA's SIR-C/X-SAR mission was to determine and compare soil moisture patterns within humid watersheds using SAR data, ground-based measurements, and hydrologic modeling. Currently available soil moisture-inversion methods using active microwave data are only accurate when applied to bare and slightly vegetated surfaces. Moreover, as the surface dries down, the number of pixels that can provide estimated soil moisture by these radar inversion methods decreases, leading to less accuracy and, confidence in the retrieved soil moisture fields at the watershed scale. The impact of these errors in microwave- derived soil moisture on hydrological modeling of vegetated watersheds has yet to be addressed. In this study a coupled water and energy balance model operating within a topographic framework is used to predict surface soil moisture for both bare and vegetated areas. In the first model run, the hydrological model is initialized using a standard baseflow approach, while in the second model run, soil moisture values derived from SIR-C radar data are used for initialization. The results, which compare favorably with ground measurements, demonstrate the utility of combining radar-derived surface soil moisture information with basin-scale hydrological modeling.

Hsu, A. Y.; ONeill, P. E.; Wood, E. F.; Zion, M.

1997-01-01

278

Modeling of forest roads impact on hydrological response  

NASA Astrophysics Data System (ADS)

Forest roads can influence the hydrologic response of upland catchments, this including river geomorphology. The presence of compacted or paved roads increases overland flow because infiltration is reduced, and the natural flow pathways are modified due to interception by road cutslopes, that convey upslope runoff, this including both surface and part of subsurface flows. Roadways, and especially roadside ditches, route road-generated runoff to the stream network. This occurs at river crossing culverts or through gullies that can be incised below road drainage facilities that are not directly stream connected, depending on the characteristics of the receiving areas. This can lead to significant changes of the natural stream network and of storm hydrographs in small catchments. The capture and redirection of road-generated water fluxes involve also geomorphic effects as the formation of gullies, the migration of channel, the triggering of shallow landslide and debris-flows. To understand the impact of forest roads on hydrologic response one need to represent the geometric and topologic interconnectivity between forest roads, road drainage systems, watershed topography and stream network. This allows for the detection of each road segment sub basin, the computation of the relative contributing area, and the extraction of a drainage network that takes into account the presence of the road network. This approach is developed here to represent the distributed hydrologic fluxes and the resulting catchment response for an experimental basin where a number of roads built in the fifties are monitored. The study area is the H.J.Andrews Experimental Forest Watershed 3 (WS3), located in the Lookout Creek basin, Western Oregon Cascades. Hydrologic simulations show that one requires a detailed description of catchment topography to capture the effect of forest roads on water flows.

Rulli, M.; Rosso, R.; Moreni, S.; Vigany, M.

2005-12-01

279

Exploring the Therapeutic Potentials of iNKT Cells for Anti-HBV Treatment  

PubMed Central

CD1d-restricted invariant NKT (iNKT) cells are a group of innate-like regulatory T cells that recognize lipid antigens. Both mouse modeling experiments and human clinical studies have suggested a key role for iNKT cells in anti-HBV immunity and these potent T cells can be explored as a novel therapeutic target for anti-HBV treatment. We aim to humanize mice in the CD1d/iNKT cell lipid presentation system and provide new research tools for identifying novel anti-HBV agents.

Lawrenczyk, Agnieszka; Kim, Seil; Wen, Xiangshu; Xiong, Ran; Yuan, Weiming

2014-01-01

280

Full implementation of a distributed hydrological model based on check dam trapped sediment volumes  

NASA Astrophysics Data System (ADS)

Lack of hydrometeorological data is one of the most compelling limitations to the implementation of distributed environmental models. Mediterranean catchments, in particular, are characterised by high spatial variability of meteorological phenomena and soil characteristics, which may prevents from transferring model calibrations from a fully gauged catchment to a totally o partially ungauged one. For this reason, new sources of data are required in order to extend the use of distributed models to non-monitored or low-monitored areas. An important source of information regarding the hydrological and sediment cycle is represented by sediment deposits accumulated at the bottom of reservoirs. Since the 60s, reservoir sedimentation volumes were used as proxy data for the estimation of inter-annual total sediment yield rates, or, in more recent years, as a reference measure of the sediment transport for sediment model calibration and validation. Nevertheless, the possibility of using such data for constraining the calibration of a hydrological model has not been exhaustively investigated so far. In this study, the use of nine check dam reservoir sedimentation volumes for hydrological and sedimentological model calibration and spatio-temporal validation was examined. Check dams are common structures in Mediterranean areas, and are a potential source of spatially distributed information regarding both hydrological and sediment cycle. In this case-study, the TETIS hydrological and sediment model was implemented in a medium-size Mediterranean catchment (Rambla del Poyo, Spain) by taking advantage of sediment deposits accumulated behind the check dams located in the catchment headwaters. Reservoir trap efficiency was taken into account by coupling the TETIS model with a pond trap efficiency model. The model was calibrated by adjusting some of its parameters in order to reproduce the total sediment volume accumulated behind a check dam. Then, the model was spatially validated by obtaining the simulated sedimentation volume at the other eight check dams and comparing it to the observed sedimentation volumes. Lastly, the simulated water discharge at the catchment outlet was compared with observed water discharge records in order to check the hydrological sub-model behaviour. Model results provided highly valuable information concerning the spatial distribution of soil erosion and sediment transport. Spatial validation of the sediment sub-model provided very good results at seven check dams out of nine. This study shows that check dams can be a useful tool also for constraining hydrological model calibration, as model results agree with water discharge observations. In fact, the hydrological model validation at a downstream water flow gauge obtained a Nash-Sutcliffe efficiency of 0.8. This technique is applicable to all catchments with presence of check dams, and only requires rainfall and temperature data and soil characteristics maps.

Bussi, Gianbattista; Francés, Félix

2014-05-01

281

Epirubicin directly promotes hepatitis B virus (HBV) replication in stable HBV-expressing cell lines: a novel mechanism of HBV reactivation following anticancer chemotherapy.  

PubMed

Chronic hepatitis B virus (HBV) infection is a worldwide problem and HBV reactivation following anticancer chemotherapy has become an emerging clinical challenge. However, the mechanisms of HBV reactivation following chemotherapy remain unclear. Epirubicin is an anthracycline drug used in chemotherapy to treat numerous types of malignancy, including breast cancer, acute leukemia, malignant lymphoma, lung cancer, ovarian cancer and stomach cancer. Epirubicin acts by intercalating DNA strands and inhibiting DNA and RNA synthesis. In this study, it was demonstrated that epirubicin directly upregulated the levels of in vitro HBV replication in a concentration-dependent manner. Exposure to epirubicin for 24 h induced >11- and 6-fold increases in the levels of intracellular and secreted HBV DNA, respectively. In concordance with the elevated levels of HBV DNA, the expression levels of HBV pregenomic RNA, intracellular HBV surface and HBV core antigens, and secreted HBV e antigen were significantly increased by treatment with 0.5 µM epirubicin. Notably, epirubicin promoted cellular excretion of HBV nucleocapsids, which are closely associated with the pathological effects of HBV, including acute liver failure. In conclusion, epirubicin exhibited a direct stimulatory effect on HBV replication and this may be a novel mechanism of HBV reactivation following cytotoxic anticancer chemotherapy. PMID:24566498

Xu, Lei; Tu, Zeng; Xu, Ge; Wang, Yuwei; Pan, Wanlong; Zhan, Xingxing; Luo, Qiang; Huang, Yuan; Chen, Juan; Huang, Ailong

2014-04-01

282

Satellite remote sensing and hydrologic modeling for flood monitoring in data poor environments  

NASA Astrophysics Data System (ADS)

Study of hydroclimatology at a range of temporal scales is important in understanding and ultimately mitigating the potential severe impacts of hydrological extreme events such as floods and droughts. Using daily in-situ data combined with the recently available satellite remote sensing data, the hydroclimatology of Nzoia basin, one of the contributing sub-catchments of Lake Victoria in the East African highlands is analyzed. The basin, with a semi-arid climate, has no sustained base flow contribution to Lake Victoria. The short spell of high discharge showed that rain is the primary cause of floods in the basin. There is only a marginal increase in annual mean discharge over the last 21 years. The 2-, 5- and 10- year peak discharges, for the entire study period showed that more years since the mid 1990s have had high peak discharges despite having relatively less annual rain. The study also presents the hydrologic model calibration and validation results over the Nzoia basin. The spatiotemporal variability of the water cycle components were quantified using a hydrologic model, with in-situ and multi-satellite remote sensing datasets. The model is calibrated using daily observed discharge data for the period between 1985 and 1999, for which model performance is estimated with a Nash Sutcliffe Efficiency (NSCE) of 0.87 and 0.23% bias. The model validation showed an error metrics with NSCE of 0.65 and 1.04% bias. Moreover, the hydrologic capability of satellite precipitation (TRMM-3B42 V6) is evaluated. In terms of reconstruction of the water cycle components the spatial distribution and time series of modeling results for precipitation and runoff showed considerable agreement with the monthly model runoff estimates and gauge observations. Runoff values responded to precipitation events that occurred across the catchment during the wet season from March to early June.The spatially distributed model inputs, states, and outputs, were found to be useful for understanding the hydrologic behavior at the catchment scale. The monthly peak runoff is observed in the months of April, May and November. The analysis revealed a linear relationship between rainfall and runoff for both wet and dry seasons. Satellite precipitation forcing data showed the potential to be used not only for the investigation of water balance but also for addressing issues pertaining to sustainability of the resources at the catchment scale. Implementation of a flood prediction system can potentially help mitigate flood induced hazards. Such a system typically requires implementation and calibration of a hydrologic model using in-situ observations (e.g. rain gauges and stream gauges). Recently, satellite remote sensing data has emerged as a viable alternative or supplement to the in-situ observations due to its availability over vast ungauged regions. The focus of this study is to integrate the best available satellite products within a semi-distributed hydrologic model to characterize the spatial extent of flooding over sparsely-gauged or ungauged basins. A satellite remote sensing based approach is proposed to calibrate a hydrologic model, simulate the spatial extent of flooding, and evaluate the probability of detecting inundated areas. A raster-based semi-distributed hydrologic model, CREST, is implemented for the Nzoia basin, a sub-basin of Lake Victoria in Africa. MODIS Terra and ASTER-based raster flood inundation maps were produced over the region and used to benchmark the hydrologic model simulations of inundated areas. The analysis showed the value of integrating satellite data such as precipitation, land cover type, topography and other data products along with space based flood inundation extents as inputs for the hydrologic model. It is concluded that the quantification of flooding spatial extent through optical sensors can help to evaluate hydrologic models and hence potentially improve hydrologic prediction and flood management strategies in ungauged catchments.

Khan, Sadiq Ibrahim

283

State updating of a distributed hydrological model with Ensemble Kalman Filtering: Effects of updating frequency and observation network density on forecast accuracy  

NASA Astrophysics Data System (ADS)

This paper presents a study on the optimal setup for discharge assimilation within a spatially distributed hydrological model (Rakovec et al., 2012a). The Ensemble Kalman filter (EnKF) is employed to update the grid-based distributed states of such an hourly spatially distributed version of the HBV-96 model. By using a physically based model for the routing, the time delay and attenuation are modelled more realistically. The discharge and states at a given time step are assumed to be dependent on the previous time step only (Markov property). Synthetic and real world experiments are carried out for the Upper Ourthe (1600 km2), a relatively quickly responding catchment in the Belgian Ardennes. The uncertain precipitation model forcings were obtained using a time-dependent multivariate spatial conditional simulation method (Rakovec et al., 2012b), which is further made conditional on preceding simulations. We assess the impact on the forecasted discharge of (1) various sets of the spatially distributed discharge gauges and (2) the filtering frequency. The results show that the hydrological forecast at the catchment outlet is improved by assimilating interior gauges. This augmentation of the observation vector improves the forecast more than increasing the updating frequency. In terms of the model states, the EnKF procedure is found to mainly change the pdfs of the two routing model storages, even when the uncertainty in the discharge simulations is smaller than the defined observation uncertainty. Rakovec, O., Weerts, A. H., Hazenberg, P., Torfs, P. J. J. F., and Uijlenhoet, R.: State updating of a distributed hydrological model with Ensemble Kalman Filtering: effects of updating frequency and observation network density on forecast accuracy, Hydrol. Earth Syst. Sci. Discuss., 9, 3961-3999, doi:10.5194/hessd-9-3961-2012, 2012a. Rakovec, O., Hazenberg, P., Torfs, P. J. J. F., Weerts, A. H., and Uijlenhoet, R.: Generating spatial precipitation ensembles: impact of temporal correlation structure, Hydrol. Earth Syst. Sci. Discuss., 9, 3087-3127, doi:10.5194/hessd-9-3087-2012, 2012b.

Rakovec, O.; Weerts, A.; Hazenberg, P.; Torfs, P.; Uijlenhoet, R.

2012-12-01

284

Improvements to the Community Land Model and their impact on the hydrological cycle  

Microsoft Academic Search

The Community Land Model version 3 (CLM3) is the land component of the Community Climate System Model (CCSM). CLM3 has energy and water biases resulting from deficiencies in some of its canopy and soil parameterizations related to hydrological processes. Recent research by the community that utilizes CLM3 and the family of CCSM models has indicated several promising approaches to alleviating

K. W. Oleson; G.-Y. Niu; Z.-L. Yang; D. M. Lawrence; P. E. Thornton; P. J. Lawrence; R. Stöckli; R. E. Dickinson; G. B. Bonan; S. Levis; A. Dai; T. Qian

2008-01-01

285

Evaluating and improving CLM hydrologic processes for integrated earth system modeling at regional scales  

Microsoft Academic Search

The community land model (CLM) was designed for coupling with atmospheric models to simulate water, energy, and carbon fluxes between the land surface and atmosphere. These fluxes are regulated in various degrees by its hydrologic processes, which have not been vigorously evaluated for applications at watershed or regional scales. In the framework of an integrated regional earth system model being

M. Huang; L. Leung; M. S. Wigmosta; A. M. Coleman; Y. Ke; T. K. Tesfa; H. Li

2010-01-01

286

Validation of a Hydrological Model for Transport of Chemicals in Rivers  

Microsoft Academic Search

Hydrologic Transport Assessment System (HYTRAS) is a software package that models contaminant transport in rivers and streams, including volatilization, adsorption\\/desorption, sedimentation, settling, and resuspension. Biodegradation, photolysis, and any other process that can be modeled using a first-order decay constant can be included as well. HYTRAS originally modeled the transport of radionuclides and has recently been expanded to include transport of

David M. Hetrick; Andrea L. Sjoreen

2004-01-01

287

Towards a regional climate model coupled to a comprehensive hydrological model  

NASA Astrophysics Data System (ADS)

When planing new ground water abstractions wells, building areas, roads or other land use activities information about expected future groundwater table location for the lifetime of the construction may be critical. The life time of an abstraction well can be expected to be more than 50 years, while if for buildings may be up to 100 years or more. The construction of an abstraction well is expensive and it is important to know if clean groundwater is available for its expected life time. The future groundwater table is depending on the future climate. With climate change the hydrology is expected to change as well. Traditionally, this assessment has been done by driving hydrological models with output from a climate model. In this way feedback between the groundwater hydrology and the climate is neglected. Neglecting this feedback can lead to imprecise or wrong results. The goal of this work is to couple the regional climate model HIRHAM (Christensen et al. 2006) to the hydrological model MIKE SHE (Graham and Butts, 2006). The coupling exploits the new OpenMI technology that provides a standardized interface to define, describe and transfer data on a time step basis between software components that run simultaneously (Gregersen et al., 2007). HIRHAM runs on a UNIX platform whereas MIKE SHE and OpenMI are under WINDOWS. Therefore the first critical task has been to develop an effective communication link between the platforms. The first step towards assessing the coupled models performance are addressed by looking at simulated land-surface atmosphere feedback through variables such as evapotranspiration, sensible heat flux and soil moisture content. Christensen, O.B., Drews, M., Christensen, J.H., Dethloff, K., Ketelsen, K., Hebestadt, I. and Rinke, A. (2006) The HIRHAM Regional Climate Model. Version 5; DMI Scientific Report 0617. Danish Meteorological Institute. Graham, D.N. and Butts, M.B. (2005) Flexible, integrated watershed modelling with MIKE SHE, In Watershed Models, (Eds. V.P. Singh & D.K. Frevert) CRC Press. Pages 245-272, ISBN: 0849336090. Gregersen, J.B., Gijsbers, P.J.A. and Westen, S.J.P. (2007) OpenMI: Open modelling interface. Journal of Hydroinformatics, 09.3, 175191. doi: 10.2166/hydro.2007.023.

Rasmussen, S. H.; Drews, M.; Christensen, J. H.; Butts, M. B.; Jensen, K. H.; Refsgaard, J.; Hydrological ModellingAssessing Climate Change Impacts At Different Scales (Hyacints)

2010-12-01

288

Multi-objective optimization for construction of prediction interval of hydrological models based on ensemble simulations  

NASA Astrophysics Data System (ADS)

Practice experience reveals that prediction interval is more reliable and informative compared to single simulation, as it indicates the precision of the forecast. However, traditional ways to implement the construction of prediction interval is very difficult. This paper proposed a novel method for constructing prediction interval based on a hydrological model ensemble. The excellent multi-objective shuffled complex differential evolution algorithm was introduced to calibrate the parameters of hydrological models so as to construct an ensemble of hydrological models, which ensures a maximum of the observed data to fall within the estimated prediction interval, and whose width is also minimized simultaneously. Meanwhile, the mean of the hydrological model ensemble can be used as single simulation. The proposed method was applied to a real world case study in order to identify the effectiveness of the construction of prediction interval for the Leaf River Watershed. The results showed that the proposed method is able to construct prediction interval appropriately and efficiently. Meanwhile, the ensemble mean can be used as single simulation because it maintains comparative forecasting accuracy as the traditional single hydrological model.

Ye, Lei; Zhou, Jianzhong; Zeng, Xiaofan; Guo, Jun; Zhang, Xinxin

2014-11-01

289

Using the SWAT model to improve process descriptions and define hydrologic partitioning in South Korea  

NASA Astrophysics Data System (ADS)

Watershed-scale modeling can be a valuable tool to aid in quantification of water quality and yield; however, several challenges remain. In many watersheds, it is difficult to adequately quantify hydrologic partitioning. Data scarcity is prevalent, accuracy of spatially distributed meteorology is difficult to quantify, forest encroachment and land use issues are common, and surface water and groundwater abstractions substantially modify watershed-based processes. Our objective is to assess the capability of the Soil and Water Assessment Tool (SWAT) model to capture event-based and long-term monsoonal rainfall-runoff processes in complex mountainous terrain. To accomplish this, we developed a unique quality-control, gap-filling algorithm for interpolation of high-frequency meteorological data. We used a novel multi-location, multi-optimization calibration technique to improve estimations of catchment-wide hydrologic partitioning. The interdisciplinary model was calibrated to a unique combination of statistical, hydrologic, and plant growth metrics. Our results indicate scale-dependent sensitivity of hydrologic partitioning and substantial influence of engineered features. The addition of hydrologic and plant growth objective functions identified the importance of culverts in catchment-wide flow distribution. While this study shows the challenges of applying the SWAT model to complex terrain and extreme environments; by incorporating anthropogenic features into modeling scenarios, we can enhance our understanding of the hydroecological impact.

Shope, C. L.; Maharjan, G. R.; Tenhunen, J.; Seo, B.; Kim, K.; Riley, J.; Arnhold, S.; Koellner, T.; Ok, Y. S.; Peiffer, S.; Kim, B.; Park, J.-H.; Huwe, B.

2014-02-01

290

A method of correction of regional climate model data for hydrological modelling  

NASA Astrophysics Data System (ADS)

Reasonable and consistent meteorological input data is a crucial factor for modelling of the river run-off at the catchment scale. The regional climate models (RCM) provide sufficient information for the hydrological modelling of impact of expected climate change on the river run-off. However, one must avoid direct usage of RCM data for the forcing of hydrological models without analysing RCM compliance with observations for the reference period. The aim of this study was to provide reasonable meteorological input data for the hydrological models to predict river run-off changes in the future. We considered the calculations made by European RCMs organised in a database at Danish Meteorological Institute under European Commission research project "PRUDENCE" EVK2-CT2001-00132. We used the observations of air temperature and precipitation for the period 1961-1990 by Hydrometeorological Agency of the former USSR in Eastern Baltic at 32 meteorological stations for comparison with RCM data. Generally, all models reasonably represent the seasonal cycle of temperature, though they overestimate winter precipitation and underestimate summer precipitation in the study area. We employed a method of RCM data correction, based on the shifting of the occurrence distribution of particular daily parameter (temperature or precipitation). Two cumulative probability curves - one of the observed data, and one of RCM data - were constructed for each day-of-the-year, for each parameter in each observation station. The correction function was constructed in a way to have equal probabilities of particular daily parameter. The correction functions are spatially interpolated, giving the possibility to create modified RCM. The time-series for the future climatic scenarios are obtained assuming that histogram modification algorithm is the same for present and future climate.

Sennikovs, J.; Bethers, U.

2009-04-01

291

Inverse modeling for field-scale hydrologic and transport parameters of fractured basalt  

SciTech Connect

A large-scale test of infiltration into a thick sequence Of fractured Snake River Plain basalts was performed during the summer of 1994 on the Idaho National Engineering Laboratory. Monitoring of moisture and tracer movement during this test provided a set of quantitative measurements from which to obtain a field-scale hydrologic description of the fractured basalts. An inverse modeling study using these quantitative measurements was performed to obtain the representative hydrologic description. This report describes the results of the inverse modeling study and includes the background and motivation for conducting the infiltration test; a brief overview of the infiltration test; descriptions of the calibration targets chosen for the simulation study, the simulation model, and the model implementation; and the simulation results with comparisons to hydrologic and tracer breakthrough data obtained from the infiltration test.

Magnuson, S.O.

1995-12-01

292

Assessment of Required Accuracy of Digital Elevation Data for Hydrologic Modeling  

NASA Technical Reports Server (NTRS)

The effect of vertical accuracy of Digital Elevation Models (DEMs) on hydrologic models is evaluated by comparing three DEMs and resulting hydrologic model predictions applied to a 7.2 sq km USDA - ARS watershed at Mahantango Creek, PA. The high resolution (5 m) DEM was resempled to a 30 m resolution using method that constrained the spatial structure of the elevations to be comparable with the USGS and SIR-C DEMs. This resulting 30 m DEM was used as the reference product for subsequent comparisons. Spatial fields of directly derived quantities, such as elevation differences, slope, and contributing area, were compared to the reference product, as were hydrologic model output fields derived using each of the three DEMs at the common 30 m spatial resolution.

Kenward, T.; Lettenmaier, D. P.

1997-01-01

293

Impact of microwave derived soil moisture on hydrologic simulations using a spatially distributed water balance model  

NASA Technical Reports Server (NTRS)

Spatial distributions of soil moisture over an agricultural watershed with a drainage area of 60 ha were derived from two NASA microwave remote sensors, and then used as a feedback to determine the initial condition for a distributed water balance model. Simulated hydrologic fluxes over a period of twelve days were compared with field observations and with model predictions based on a streamflow derived initial condition. The results indicated that even the low resolution remotely sensed data can improve the hydrologic model's performance in simulating the dynamics of unsaturated zone soil moisture. For the particular watershed under study, the simulated water budget was not sensitive to the resolutions of the microwave sensors.

Lin, D. S.; Wood, E. F.; Famiglietti, J. S.; Mancini, M.

1994-01-01

294

Brief summary of LADHS: Los Alamos distributed hydrologic modeling system.  

SciTech Connect

This report describes the current state of the fourth Thrust Area of the NSF Science and Technology Center for the Sustainability of Semi-Arid Hydrology and Riparian Areas (SAHRA). Sustainability of semi-arid regions has become a serious political and scientific concern. Increasing population has added stress to the water supply and other natural resources, notably, underground aquifers. Recent controversies in the Rio Grande Basin involving the competing interests of endangered species and humans for water have highlighted the delicate balance of biologically diverse southwestern riparian areas. Potentially, the warming climate may intensify summer storms and affect the amount and timing of snow melt, the largest renewable source of water in the southwest. It is, therefore, of great political, social and scientific interest to determine ways in which human activities can coexist with healthy riparian areas and a plentiful, clean water supply over the long run. An understanding of how all of these processes interrelate would allow regional decision-makers to consider a wide range of options and thereby develop useful plans for meeting societal needs. To make the best use of limited fresh water resources, decision makers must be able to make predictions about the entire hydrologic cycle, which is a complex combination of physical, chemical, and biological processes. Only then could they explore the potential effects of increased water use and of changes in the regional climate. The important processes in the hydrologic cycle include rainfall, snowmelt, storms, runoff, and flow in ephemeral streams, rivers, and underground aquifers. Riparian communities and evaporation play key roles in reducing the available water.

Murray, R. E. (Regan E.); Winter, C. L. (C. Larrabee); Springer, E. P.; Costigan, K. R. (Keeley R.); Tseng, P. H. (Peng-Hsiang)

2001-01-01

295

Estimation of climate change impacts on river flow and catchment hydrological connectivity incorporating uncertainty from multiple climate models, stochastic downscaling and hydrological model parameterisation error sources  

NASA Astrophysics Data System (ADS)

When estimating climate change impacts, there are many sources of uncertainty which must be considered. The main sources of uncertainty arise from the structure and parameterisation of physically based simulation models, downscaling methods, stochastic realisations of future weather time series and the underlying emission scenarios. This work focuses on the uncertainties resulting from the use of multiple climate models and the joint impact of the stochastic realisations of future weather time series from a weather generator, EARWIG, and from parameter estimation uncertainty of a hydrological model, CAS-Hydro. These tools have been applied to the River Rye, Yorkshire. A suite of model parameter sets and weather realisations have been used to project likely changes to the hydrological functioning under climate change. Results are presented on the projected changes in flow duration curves and the potential changes in the hydrological connectivity by overland flow within the catchment. The statistical sensitivity of the impact predictions to these sources of uncertainty and the use of a multi-model ensemble to enable the production of probabilistic estimates of change is assessed. These estimates of potential changes in flow can then be used to inform the adaptation of water resources design and management.

Reaney, S. M.; Fowler, H. J.

2008-12-01

296

Automatic Calibration of a Semi-Distributed Hydrologic Model Using Particle Swarm Optimization  

NASA Astrophysics Data System (ADS)

Hydrologic simulation models need to be calibrated and validated before using them for operational predictions. Spatially-distributed hydrologic models generally have a large number of parameters to capture the various physical characteristics of a hydrologic system. Manual calibration of such models is a very tedious and daunting task, and its success depends on the subjective assessment of a particular modeler, which includes knowledge of the basic approaches and interactions in the model. In order to alleviate these shortcomings, an automatic calibration model, which employs an evolutionary optimization technique known as Particle Swarm Optimizer (PSO) for parameter estimation, is developed. PSO is a heuristic search algorithm that is inspired by social behavior of bird flocking or fish schooling. The newly-developed calibration model is integrated to the U.S. Department of Agriculture's Soil and Water Assessment Tool (SWAT). SWAT is a physically-based, semi-distributed hydrologic model that was developed to predict the long term impacts of land management practices on water, sediment and agricultural chemical yields in large complex watersheds with varying soils, land use, and management conditions. SWAT was calibrated for streamflow and sediment concentration. The calibration process involves parameter specification, whereby sensitive model parameters are identified, and parameter estimation. In order to reduce the number of parameters to be calibrated, parameterization was performed. The methodology is applied to a demonstration watershed known as Big Creek, which is located in southern Illinois. Application results show the effectiveness of the approach and model predictions are significantly improved.

Bekele, E. G.; Nicklow, J. W.

2005-12-01

297

Identifying Droughts by Modeling the Hydrologic and Ecologic Responses in the Medjerda River Basin, Tunisia  

NASA Astrophysics Data System (ADS)

Drought brings severe damage to water and agricultural resources, and both of hydrological and ecological responses are important for understanding droughts. However, the ecological contributions to drought characteristics at the basin scale have not been quantified. To address this issue, we developed an eco-hydrological model that can calculate vegetation dynamics as a diagnostic valuable in a distributed-hydrological modeling framework and identified different drought types in the Medjerda River Basin where drought is a predominant issue. From the inputs and outputs of the model, we calculate drought indices for different drought types. The model shows reliable accuracy in reproducing the observed river discharge and the satellite observed leaf area index in the long-term (19-year) simulation. Moreover, the drought index calculated from model estimated annual peak of leaf area index is well correlated (correlation coefficient; r = 0.89; see Figure) with drought index from nationwide annual crop production, which show the modeled leaf area index has enough capacity to reproducing agricultural droughts that can be related with historical food shortage on 1988-1989 and 1993-1995. Our model can estimate vegetation dynamics and water cycle simultaneously in the enough accuracy to analyze the basin-scale agricultural and hydrological droughts separately. We clarify that vegetation dynamics has quicker response to meteorological droughts than river discharge and groundwater dynamics in Medjerda River Basin because vegetation dynamics is sensitive to soil moisture in surface layers while soil moisture in deeper layers strongly contributes to stream flow and depth of groundwater level. Therefore, historical agricultural droughts predominantly occurred prior to hydrological droughts and in the 1988-1989 drought, the hydrological drought lasted much longer even after crop production recovered. Standardized anomaly index (SA) for estimated annual maximum leaf area index (green line) from model and observed annual crop production in Tunisia (orange line).

Sawada, Y.; Koike, T.; Jaranilla-sanchez, P. A.

2013-12-01

298

A digital hydrological model of high, cold alpine areas and its application  

NASA Astrophysics Data System (ADS)

In a watershed of high cold alpine areas mainly supplemented with melted snow, glacier water and rainfall, the spatial distribution of runoff is extremely uneven over the whole region. With the development of DEMs and the advances on GIS technology, digital hydrology was developed, digital hydrology construction was enriched, and powerful technical support was provided to the discipline in recent years. Models can preferably reappear represent real hydrology processes; moreover the selection of partial parameters has the persuasive power to overcome the influences of artificial and subjective factors. Utilizing the technology of remote sensing (RS) and GIS the space distribution of underlying information, intermediate-state information and cover information of basin snow cover each time RS images are acquired and portrayed in the study of basin hydrologic processes. Based on the Xinanjiang Model, a digital hydrological model which suits streams mainly supplemented with melted snow, glacial water and rainfall in alpine regions was established. The model was applied to simulate snowmelt-runoff in 2005.The results were good and reflect the actual changing trend of in runoff. The deterministic coefficient of forecast projections is 0.812.

Mu, Zhenxia; Jiang, Huifang; Peng, Liang; He, Ying

2010-11-01

299

Prospective comparison of Abbott RealTime HBV DNA and Versant HBV DNA 3.0 assays for hepatitis B DNA quantitation: impact on HBV genotype monitoring.  

PubMed

The quantitation of human hepatitis B virus (HBV) in the serum of infected patients is recommended to characterize the course of chronic HBV infection. The aim of this prospective study was to evaluate the performance of the Abbott RealTime PCR assay for HBV DNA quantitation by comparison with the standard Versant HBV DNA 3.0 assay. The better sensitivity and broader dynamic range of HBV DNA quantitation using the Abbott RealTime PCR assay was confirmed by the study of 362 serum samples from 311 patients. In addition, data analysis revealed the concordance of HBV DNA quantitations between the two assays. When this evaluation was assessed as a function of HBV genotype, there was discordance for HBV genotype C samples. Thus, we performed an in-house PCR to confirm the discrepancy observed regarding the HBV genotypes. The in-house PCR results agreed better with the Abbott RealTime PCR method when compared with the standard hybridization assay. In conclusion, the wide dynamic range of HBV DNA quantitation achieved with the Abbott RealTime PCR assay makes it appropriate for the clinical monitoring of HBV infected patients. However, a change of HBV DNA quantitation method could influence results on the follow-up of HBV genotype C infected patients. PMID:18929599

Pol, Jonathan; Le Pendeven, Catherine; Beby-Defaux, Agnes; Rabut, Elodie; Jais, Jean Philippe; Pilloux, Marilyse; Osada, Catherine; Zatla, Fadila; Assami, Hichem; Grange, Jean Didier; Kremsdorf, Dina; Nicolas, Jean Claude; Soussan, Patrick

2008-12-01

300

Synthesis and biological evaluation of nucleoside analogues than contain silatrane on the basis of the structure of acyclovir (ACV) as novel inhibitors of hepatitis B virus (HBV).  

PubMed

Hepatitis B virus (HBV) infection causes major public health problems worldwide. Acyclovir (ACV) is mainly used to inhibit herpes simplex virus (HSV) rather than HBV. In this study, we used the combination principle to design and synthesize nucleoside analogues that contain silatrane on the basis of the structure of ACV. We found that the compounds were effective inhibitors of HBV, both in vitro and in vivo. All of the compounds showed suppressive activity on the expression of HBV surface antigen (HBsAg) and HBV e antigen (HBeAg) in the HepG2.2.15 cell line with low cytotoxicity. One of compounds was studied in HBV transgenic mice model, and the test results showed its ability to reduce the levels of HBsAg, HBeAg and HBV DNA by ELASE and qPCR. Furthermore, significant improvement of T lymphocyte was observed after treatment, as evaluated by flow cytometry (FCM). PMID:23369536

Han, Anyue; Li, Lingna; Qing, Kuiyou; Qi, Xiaolu; Hou, Leping; Luo, Xintong; Shi, Shaohua; Ye, Faqing

2013-03-01

301

Upscaling Empirically Based Conceptualisations to Model Tropical Dominant Hydrological Processes for Historical Land Use Change  

NASA Astrophysics Data System (ADS)

Surface runoff and percolation to ground water are two hydrological processes of concern to the Atlantic slope of Costa Rica because of their impacts on flooding and drinking water contamination. As per legislation, the Costa Rican Government funds land use management from the farm to the regional scale to improve or conserve hydrological ecosystem services. In this study, we examined how land use (e.g., forest, coffee, sugar cane, and pasture) affects hydrological response at the point, plot (1 m2), and the field scale (1-6ha) to empirically conceptualize the dominant hydrological processes in each land use. Using our field data, we upscaled these conceptual processes into a physically-based distributed hydrological model at the field, watershed (130 km2), and regional (1500 km2) scales. At the point and plot scales, the presence of macropores and large roots promoted greater vertical percolation and subsurface connectivity in the forest and coffee field sites. The lack of macropores and large roots, plus the addition of management artifacts (e.g., surface compaction and a plough layer), altered the dominant hydrological processes by increasing lateral flow and surface runoff in the pasture and sugar cane field sites. Macropores and topography were major influences on runoff generation at the field scale. Also at the field scale, antecedent moisture conditions suggest a threshold behavior as a temporal control on surface runoff generation. However, in this tropical climate with very intense rainstorms, annual surface runoff was less than 10% of annual precipitation at the field scale. Significant differences in soil and hydrological characteristics observed at the point and plot scales appear to have less significance when upscaled to the field scale. At the point and plot scales, percolation acted as the dominant hydrological process in this tropical environment. However, at the field scale for sugar cane and pasture sites, saturation-excess runoff increased as irrigation intensity and duration (e.g., quantity) increased. Upscaling our conceptual models to the watershed and regional scales, historical data (1970-2004) was used to investigate whether dominant hydrological processes changed over time due to land use change. Preliminary investigations reveal much higher runoff coefficients (<30%) at the larger watershed scales. The increase in importance of runoff at the larger geographic scales suggests an emerging process and process non-linearity between the smaller and larger scales. Upscaling is an important and useful concept when investigating catchment response using the tools of field work and/or physically distributed hydrological modeling.

Toohey, R.; Boll, J.; Brooks, E.; Jones, J.

2009-12-01

302

Coupling urban expansion models and hydrological models: how important are spatial patterns?  

NASA Astrophysics Data System (ADS)

It is well known that urban expansion has a significant impact on the surface water balance by transforming vegetated covers into sealed surfaces, such as buildings, roads and parking spaces. These changes alter several hydrological processes at various spatial and temporal scales and thus cause changing fluxes of evapotranspiration, surface runoff and groundwater recharge. In order to estimate the impact of urban expansion on the surface hydrology, hydrological models are often ‘loosely' coupled with different types of urban expansion models. It is, however, not clear to what extent spatially-explicit urban expansion scenarios provide an added value in comparison with non-spatial urban expansion models at different scale levels. The objective of this study is to acquire a better insight in the importance of scale effects involved in the loose coupling of urban expansion scenarios and hydrological models. The relative importance of using different projections of both (i) quantity and (ii) spatial patterns of urban expansion was analysed at four different scale levels. The highly urbanised Flanders-Brussels region was taken as an example application. A number of urban expansion scenarios for 2025 and 2050, that varied in terms of quantity and spatial pattern of urban expansion, was developed and subsequently used as an input in the hydrological model WetSpass. WetSpass is a physically based spatially-distributed water balance model for simulating seasonal and yearly groundwater recharge, actual evapotranspiration and surface runoff. The results obtained suggest that at the level of the Flanders-Brussels region, an accurate estimation of the quantity of urban expansion should get priority over an accurate projection of the spatial patterns. The quantity uncertainty related to the use of different urban expansion scenarios resulted in a 17% uncertainty on the assessed runoff values, 1.5% on the evapotranspiration values and 4.5% on the estimated groundwater recharge. Comparable uncertainty values could be observed on all four analysed scale levels. On the other hand, the importance of using accurate projections of the spatial pattern of urban expansion increased systematically with an increasing spatial resolution. At the level of individual subcatchments the uncertainty related to the spatial patterns of urban expansion equalled the uncertainty related to the quantity assessment. At the level of individual pixels, an accurate projection of the spatial patterns was even found to be more important than an accurate assessment of the quantities of urban growth. Based on the results from this study it can be concluded that a uniform strategy for coupling urban expansion models and hydrological models seems inappropriate. The smaller the area under investigation, the more effort should be put in an accurate simulation of the spatial patterns of land cover change. These findings are highly relevant for water management and spatial planning policymakers that typically operate at different administrative levels.

Poelmans, Lien; van Rompaey, Anton; Batelaan, Okke

2010-05-01

303

Hydrological forecasting  

SciTech Connect

The authors present a report on the technologies now available in the rapidly growing field of hydrological forecasting. The volume covers the major hydrological areas relevant to the watershed, as opposed to the hillslope, scale, and discusses the latest simulation models in use. Included is material on modeling strategies, soil water modeling, the use of radar for precipitation measurements, remote sensing of soil moisture, modeling changes in forest evapotranspiration, and snow and ice. Also presented is information on groundwater forecasting, water quality, lumped catchment models, variable source area models, and distributed models.

Anderson, M.G.; Burt, T.P.

1985-01-01

304

Reducing hydrologic model uncertainty in monthly streamflow predictions using multimodel combination  

NASA Astrophysics Data System (ADS)

Model errors are inevitable in any prediction exercise. One approach that is currently gaining attention in reducing model errors is by combining multiple models to develop improved predictions. The rationale behind this approach primarily lies on the premise that optimal weights could be derived for each model so that the developed multimodel predictions will result in improved predictions. A new dynamic approach (MM-1) to combine multiple hydrological models by evaluating their performance/skill contingent on the predictor state is proposed. We combine two hydrological models, "abcd" model and variable infiltration capacity (VIC) model, to develop multimodel streamflow predictions. To quantify precisely under what conditions the multimodel combination results in improved predictions, we compare multimodel scheme MM-1 with optimal model combination scheme (MM-O) by employing them in predicting the streamflow generated from a known hydrologic model (abcd model orVICmodel) with heteroscedastic error variance as well as from a hydrologic model that exhibits different structure than that of the candidate models (i.e., "abcd" model or VIC model). Results from the study show that streamflow estimated from single models performed better than multimodels under almost no measurement error. However, under increased measurement errors and model structural misspecification, both multimodel schemes (MM-1 and MM-O) consistently performed better than the single model prediction. Overall, MM-1 performs better than MM-O in predicting the monthly flow values as well as in predicting extreme monthly flows. Comparison of the weights obtained from each candidate model reveals that as measurement errors increase, MM-1 assigns weights equally for all the models, whereas MM-O assigns higher weights for always the best-performing candidate model under the calibration period. Applying the multimodel algorithms for predicting streamflows over four different sites revealed that MM-1 performs better than all single models and optimal model combination scheme, MM-O, in predicting the monthly flows as well as the flows during wetter months.

Li, Weihua; Sankarasubramanian, A.

2012-12-01

305

Moving university hydrology education forward with community-based geoinformatics, data and modeling resources  

NASA Astrophysics Data System (ADS)

In this opinion paper, we review recent literature related to data and modeling driven instruction in hydrology, and present our findings from surveying the hydrology education community in the United States. This paper presents an argument that that data and modeling driven geoscience cybereducation (DMDGC) approaches are essential for teaching the conceptual and applied aspects of hydrology, as a part of the broader effort to improve science, technology, engineering, and mathematics (STEM) education at the university level. The authors have undertaken a series of surveys and a workshop involving university hydrology educators to determine the state of the practice of DMDGC approaches to hydrology. We identify the most common tools and approaches currently utilized, quantify the extent of the adoption of DMDGC approaches in the university hydrology classroom, and explain the community's views on the challenges and barriers preventing DMDGC approaches from wider use. DMDGC approaches are currently emphasized at the graduate level of the curriculum, and only the most basic modeling and visualization tools are in widespread use. The community identifies the greatest barriers to greater adoption as a lack of access to easily adoptable curriculum materials and a lack of time and training to learn constantly changing tools and methods. The community's current consensus is that DMDGC approaches should emphasize conceptual learning, and should be used to complement rather than replace lecture-based pedagogies. Inadequate online material publication and sharing systems, and a lack of incentives for faculty to develop and publish materials via such systems, is also identified as a challenge. Based on these findings, we suggest that a number of steps should be taken by the community to develop the potential of DMDGC in university hydrology education, including formal development and assessment of curriculum materials, integrating lecture-format and DMDGC approaches, incentivizing the publication by faculty of excellent DMDGC curriculum materials, and implementing the publication and dissemination cyberinfrastructure necessary to support the unique DMDGC digital curriculum materials.

Merwade, V.; Ruddell, B. L.

2012-08-01

306

Moving university hydrology education forward with geoinformatics, data and modeling approaches  

NASA Astrophysics Data System (ADS)

In this opinion paper, we review recent literature related to data and modeling driven instruction in hydrology, and present our findings from surveying the hydrology education community in the United States. This paper presents an argument that that Data and Modeling Driven Geoscience Cybereducation (DMDGC) approaches are valuable for teaching the conceptual and applied aspects of hydrology, as a part of the broader effort to improve Science, Technology, Engineering, and Mathematics (STEM) education at the university level. The authors have undertaken a series of surveys and a workshop involving the community of university hydrology educators to determine the state of the practice of DMDGC approaches to hydrology. We identify the most common tools and approaches currently utilized, quantify the extent of the adoption of DMDGC approaches in the university hydrology classroom, and explain the community's views on the challenges and barriers preventing DMDGC approaches from wider use. DMDGC approaches are currently emphasized at the graduate level of the curriculum, and only the most basic modeling and visualization tools are in widespread use. The community identifies the greatest barriers to greater adoption as a lack of access to easily adoptable curriculum materials and a lack of time and training to learn constantly changing tools and methods. The community's current consensus is that DMDGC approaches should emphasize conceptual learning, and should be used to complement rather than replace lecture-based pedagogies. Inadequate online material-publication and sharing systems, and a lack of incentives for faculty to develop and publish materials via such systems, is also identified as a challenge. Based on these findings, we suggest that a number of steps should be taken by the community to develop the potential of DMDGC in university hydrology education, including formal development and assessment of curriculum materials integrating lecture-format and DMDGC approaches, incentivizing the publication by faculty of excellent DMDGC curriculum materials, and implementing the publication and dissemination cyberinfrastructure necessary to support the unique DMDGC digital curriculum materials.

Merwade, V.; Ruddell, B. L.

2012-02-01

307

Water regime of Playa Lakes from southern Spain: conditioning factors and hydrological modeling.  

PubMed

Andalusia's lowland countryside has a network of small geographically isolated playa lakes scattered across an area of 9000 km2 whose watersheds are mostly occupied by clayey rocks. The hydrological model proposed by the authors seeks to find equilibrium among usefulness, simplicity, and applicability to isolated playas in a semiarid context elsewhere. Based in such model, the authors have used monthly climatic data, water stage measurements, and the basin morphometry of a particular case (Los Jarales playa lake) to calibrate the soil water budget in the catchment and the water inputs from the watershed (runoff plus groundwater flow) at different scales, from monthly to daily. After the hydrologic model was calibrated, the authors implemented simulations with the goal of reproducing the past hydrological dynamics and forecasting water regime changes that would be caused by a modification of the wetland morphometry. PMID:23944145

Moral, Francisco; Rodriguez-Rodriguez, Miguel; Beltrán, Manuel; Benavente, José; Cifuentes, Victor Juan

2013-07-01

308

Gravity effects obtained from global hydrology models in comparison with high precision gravimetric time series  

NASA Astrophysics Data System (ADS)

Water mass changes are a major source of variations in residual gravimetric time series obtained from the combination of observations with superconducting and absolute gravimeters. Changes in the local water storage are the main influence, but global variations contribute to the signal significantly. For three European gravity stations, Bad Homburg, Wettzell and Medicina, different global hydrology models are compared. The influence of topographic effects is discussed and due to the long-term stability of the combined gravity time series, inter-annual signals in model data and gravimetric observations are compared. Two sources of influence are discriminated, i.e., the effect of a local zone with an extent of a few kilometers around the gravimetric station and the global contribution beyond 50km. Considering their coarse resolution and uncertainties, local effects calculated from global hydrological models are compared with the in-situ gravity observations and, for the station Wettzell, with local hydrological monitoring data.

Wziontek, Hartmut; Wilmes, Herbert; Güntner, Andreas; Creutzfeldt, Benjamin

2010-05-01

309

COMPARISON OF SIMULATION RESULTS USING SSURGO-BASED AND STATSGO-BASED PARAMETERS IN A DISTRIBUTED HYDROLOGIC MODEL  

Microsoft Academic Search

Better estimation of a priori gridded parameters is a significant element in the operational implementation of a distributed hydrologic model in the National Oceanic and Atmospheric Administration's (NOAA) National Weather Service. Improved a priori parameters have the potential to reduce the cost of calibration of distributed hydrologic models. Calibration costs are a key hurdle to overcome in using distributed models

Ziya Zhang; Victor Koren; Seann Reed

310

Incorporating a Spatially Dynamic Conceptualization of Dominant Processes into Hydrological Models  

NASA Astrophysics Data System (ADS)

In certain applications of hydrological models, such as the prediction of diffuse pollution transfers, the spatial distribution of hydrological processes need to be conceptualized in a physical meaningful way. In this study, results from GPS-based field mapping were used to conceptualize spatially distributed processes that control the dynamics of fast, near-surface runoff generation processes, which dominate the hydrological response of a mesoscale catchment in the Scottish Highlands. The catchment is dominated by responsive soils such as histosols and gleysols in wide valley bottom saturated areas that are characterized by their dynamic expansion and contraction. We observed a maximum expansion of up to 30 % of the total catchment area under wet conditions when the catchment is highly connected and less than 5 % during prolonged dry periods. The conceptualization of such processes formed the basis for the implementation of simple low-parameterized model approaches highlighting the need for a spatially dynamic representation of the catchment functioning. Preliminary results for wet and dry extreme periods indicate that the model agrees well with the observed dynamics of saturated zones hydrologically connected to the stream channel network and their subsequent disconnection. We conclude that such characterization of hydrological process heterogeneity is important for an improved understanding of these catchment systems and predicting water and solute fluxes.

Birkel, C.; Tetzlaff, D.; Dunn, S. M.; Soulsby, C.

2009-04-01

311

Incorporating a Spatially Dynamic Conceptualization of Dominant Processes into Hydrological Models  

NASA Astrophysics Data System (ADS)

In certain applications of hydrological models, such as the prediction of diffuse pollution transfers, the spatial distribution of hydrological processes need to be conceptualized in a physical meaningful way. In this study, results from GPS-based field mapping were used to conceptualize spatially distributed processes that control the dynamics of fast, near-surface runoff generation processes, which dominate the hydrological response of a mesoscale catchment in the Scottish Highlands. The catchment is dominated by responsive soils such as histosols and gleysols in wide valley bottom saturated areas that are characterized by their dynamic expansion and contraction. We observed a maximum expansion of up to 30 % of the total catchment area under wet conditions when the catchment is highly connected and less than 5 % during prolonged dry periods. The conceptualization of such processes formed the basis for the implementation of simple low- parameterized model approaches highlighting the need for a spatially dynamic representation of the catchment functioning. Preliminary results for wet and dry extreme periods indicate that the model agrees well with the observed dynamics of saturated zones hydrologically connected to the stream channel network and their subsequent disconnection. We conclude that such characterization of hydrological process heterogeneity is important for an improved understanding of these catchment systems and predicting water and solute fluxes.

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

2008-12-01

312

The implementation and validation of improved land-surface hydrology in an atmospheric general circulation model  

NASA Technical Reports Server (NTRS)

New land-surface hydrologic parameterizations are implemented into the NASA Goddard Institute for Space Studies (GISS) General Circulation Model (GCM). These parameterizations are: 1) runoff and evapotranspiration functions that include the effects of subgrid-scale spatial variability and use physically based equations of hydrologic flux at the soil surface and 2) a realistic soil moisture diffusion scheme for the movement of water and root sink in the soil column. A one-dimensional climate model with a complete hydrologic cycle is used to screen the basic sensitivities of the hydrological parameterizations before implementation into the full three-dimensional GCM. Results of the final simulation with the GISS GCM and the new land-surface hydrology indicate that the runoff rate, especially in the tropics, is significantly improved. As a result, the remaining components of the heat and moisture balance show similar improvements when compared to observations. The validation of model results is carried from the large global (ocean and land-surface) scale to the zonal, continental, and finally the regional river basin scales.

Johnson, Kevin D.; Entekhabi, Dara; Eagleson, Peter S.

1993-01-01

313

Digital Hydrologic Networks Supporting Applications Related to Spatially Referenced Regression Modeling1  

PubMed Central

Abstract Digital hydrologic networks depicting surface-water pathways and their associated drainage catchments provide a key component to hydrologic analysis and modeling. Collectively, they form common spatial units that can be used to frame the descriptions of aquatic and watershed processes. In addition, they provide the ability to simulate and route the movement of water and associated constituents throughout the landscape. Digital hydrologic networks have evolved from derivatives of mapping products to detailed, interconnected, spatially referenced networks of water pathways, drainage areas, and stream and watershed characteristics. These properties are important because they enhance the ability to spatially evaluate factors that affect the sources and transport of water-quality constituents at various scales. SPAtially Referenced Regressions On Watershed attributes (SPARROW), a process-based/statistical model, relies on a digital hydrologic network in order to establish relations between quantities of monitored contaminant flux, contaminant sources, and the associated physical characteristics affecting contaminant transport. Digital hydrologic networks modified from the River Reach File (RF1) and National Hydrography Dataset (NHD) geospatial datasets provided frameworks for SPARROW in six regions of the conterminous United States. In addition, characteristics of the modified RF1 were used to update estimates of mean-annual streamflow. This produced more current flow estimates for use in SPARROW modeling. PMID:22457575

Brakebill, JW; Wolock, DM; Terziotti, SE

2011-01-01

314

GIS/RS-based Integrated Eco-hydrologic Modeling in the East River Basin, South China  

NASA Astrophysics Data System (ADS)

Land use/cover change (LUCC) has significantly altered the hydrologic system in the East River (Dongjiang) Basin. Quantitative modeling of hydrologic impacts of LUCC is of great importance for water supply, drought monitoring and integrated water resources management. An integrated eco-hydrologic modeling system of Distributed Monthly Water Balance Model (DMWBM), Surface Energy Balance System (SEBS) was developed with aid of GIS/RS to quantify LUCC, to conduct physically-based ET (evapotranspiration) mapping and to predict hydrologic impacts of LUCC. To begin with, in order to evaluate LUCC, understand implications of LUCC and provide boundary condition for the integrated eco-hydrologic modeling, firstly the long-term vegetation dynamics was investigated based on Normalized Difference Vegetation Index (NDVI) data, and then LUCC was analyzed with post-classification methods and finally LUCC prediction was conducted based on Markov chain model. The results demonstrate that the vegetation activities decreased significantly in summer over the years. Moreover, there were significant changes in land use/cover over the past two decades. Particularly there was a sharp increase of urban and built-up area and a significant decrease of grassland and cropland. All these indicate that human activities are intensive in the East River Basin and provide valuable information for constructing scenarios for studying hydrologic impacts of LUCC. The physically-remote-sensing-based Surface Energy Balance System (SEBS) was employed to estimate areal actual ET for a large area rather than traditional point measurements . The SEBS was enhanced for application in complex vegetated area. Then the inter-comparison with complimentary ET model and distributed monthly water balance model was made to validate the enhanced SEBS (ESEBS). The application and test of ESEBS show that it has a good accuracy both monthly and annually and can be effectively applied in the East River Basin. The results of ET mapping based on ESEBS demonstrate that actual ET in the East River Basin decreases significantly in the last two decades, which is probably caused by decrease of sunshine duration. In order to effectively simulate hydrologic impact of LUCC, an integrated model of ESEBS and distributed monthly water balance model has been developed in this study. The model is capable of considering basin terrain and the spatial distribution of precipitation and soil moisture. Particularly, the model is unique in accounting for spatial and temporal variations of vegetation cover and ET, which provides a powerful tool for studying the hydrologic impacts of LUCC. The model was applied to simulate the monthly runoff for the period of 1980-1994 for model calibration and for the period of 1995-2000 for validation. The calibration and validation results show that the newly integrated model is suitable for simulating monthly runoff and studying hydrologic impacts ofLUCC in the East River Basin. Finally, the newly integrated model was firstly applied to analyze the relationship of land use and hydrologic regimes based on the land use maps in 1980 and 2000. Then the newly integrated model was applied to simulate the potential impacts of land use change on hydrologic regimes in the East River Basin under a series of hypothetical scenarios. The results show that ET has a positive relationship with Leaf Area Index (LAI) while runoff has a negative relationship with LAI in the same climatic zone, which can be elaborated by surface energy balance and water balance equation. Specifically, on an annual basis, ET of forest scenarios is larger than that of grassland or cropland scenarios. On the contrary, runoff of forest scenarios is less than that of grassland or cropland scenarios. On a monthly basis, for most of the scenarios, particularly the grassland and cropland scenarios, the most significant changes occurred in the rainy season. The results indicate that deforestation would cause increase of runoff and decrease of ET on an annual basis in the East River Basin. On a monthly basis, de

Wang, Kai

315

A LAND-SURFACE HYDROLOGY PARAMETERIZATION WITH SUBGRID VARIABILITY FOR GENERAL CIRCULATION MODELS  

EPA Science Inventory

Most of the existing generation of general circulation models (GCMs) use so-called bucket algorithms to represent land-surface hydrology. iosphere-atmosphere models that include the transfer of energy, mass, and momentum between the atmosphere and the land surface are a recent al...

316

Hydrologic Modeling of a Canal-Irrigated Agricultural Watershed with Irrigation Best Management  

E-print Network

Case Study Hydrologic Modeling of a Canal-Irrigated Agricultural Watershed with Irrigation Best Management Practices: Case Study N. Kannan1 ; J. Jeong2 ; and R. Srinivasan3 Abstract: Simulating irrigation canal-irrigated watersheds. The existing approaches to modeling canal irrigation use situation

317

The application of remote sensing to the development and formulation of hydrologic planning models  

NASA Technical Reports Server (NTRS)

Regional hydrologic planning models built upon remote sensing capabilities and suited for ungaged watersheds are developed. The effectiveness of such models is determined along with which parameters impact most the minimization of errors associated with the prediction of peak flow events (floods). Emphasis is placed on peak flood prediction because of its significance to users for the purpose of planning, sizing, and designing waterworks.

Castruccio, P. A.; Loats, H. L., Jr.; Fowler, T. R.; Frech, S. L.

1975-01-01

318

Energy conservative algorithm for phase change in freezing unsaturated soils using the hydrological model GEOtop  

Microsoft Academic Search

GEOtop is a distributed physically-based hydrological model with coupled water and energy budgets, and is currently under development to suit the requirements of permafrost research in complex mountain terrains. The phase transition is extremely important if the soil temperature in permafrost regions has to be modeled. At the same time, the transport of water and thus variable water (or ice)

M. Dall'Amico; S. Endrizzi; S. Gruber; R. Rigon

2009-01-01

319

The Hydrology of Malaria: Model Development and Application to a Sahelian Village  

NASA Astrophysics Data System (ADS)

We present a coupled hydrology and entomology model for the mechanistic simulation of local-scale response of malaria transmission to hydrological and climatological determinants in semi-arid, desert fringe environments. The model is applied to the Sahel village of Banizoumbou, Niger, to predict interannual variability in malaria vector mosquito populations which lead to variations in malaria transmission. Using a high-resolution, small-scale distributed hydrology model that incorporates remotely-sensed data for land cover and topography, we simulate the formation and persistence of the pools constituting the primary breeding habitat of Anopheles gambiae s.l. mosquitoes, the principal regional malaria vector mosquitoes. An agent-based mosquito population model is coupled to the distributed hydrology model, with aquatic stage and adult stage components. For each individual adult mosquito, the model tracks attributes relevant to population dynamics and malaria transmission, which are updated as mosquitoes interact with their environment, humans, and animals. Weekly field observations were made in 2005 and 2006. The model reproduces mosquito population variability at seasonal and interannual time scales, and highlights individual pool persistence as a dominant control. Future developments to the presented model can be used in the evaluation of impacts of climate change on malaria, as well as the a priori evaluation of environmental management-based interventions.

Bomblies, A.; Duchemin, J.; Eltahir, E. A.

2008-12-01

320

Improved treatment of uncertainty in hydrologic modeling: Combining the strengths of global optimization and data assimilation  

Microsoft Academic Search

Hydrologic models use relatively simple mathematical equations to conceptualize and aggregate the complex, spatially distributed, and highly interrelated water, energy, and vegetation processes in a watershed. A consequence of process aggregation is that the model parameters often do not represent directly measurable entities and must therefore be estimated using measurements of the system inputs and outputs. During this process, known

Jasper A. Vrugt; Cees G. H. Diks; Hoshin V. Gupta; Willem Bouten; Jacobus M. Verstraten

2005-01-01

321

Use of boundary layer scintillometer data for spatially distributed hydrologic model validation  

Microsoft Academic Search

An accurate understanding of the behavior of the different water and energy balance terms at the catchment scale is of interest for hydrologic modeling and operational flood forecasting. Flood forecast models are usually based on two different kinds of meteorological inputs, more specifically the catchment averaged precipitation and evapotranspiration rates. These are then related to the catchment discharge through a

B. Samain; B. V. A. Ferket; W. Defloor; V. R. N. Pauwels

2009-01-01

322

VERIFICATION OF THE HYDROLOGIC EVALUATION OF LANDFILL PERFORMANCE (HELP) MODEL USING FIELD DATA  

EPA Science Inventory

The report describes a study conducted to verify the Hydrologic Evaluation of Landfill Performance (HELP) computer model using existing field data from a total of 20 landfill cells at 7 sites in the United States. Simulations using the HELP model were run to compare the predicted...

323

HBV cccDNA in patients' sera as an indicator for HBV reactivation and an early signal of liver damage  

Microsoft Academic Search

AIM: To evaluate the covalently closed circle DNA (cccDNA) level of hepatitis B virus (HBV) in patients' liver and sera. METHODS: HBV DNA was isolated from patients' liver biopsies and sera. A sensitive real-time PCR method, which is capable of differentiation of HBV viral genomic DNA and cccDNA, was used to quantify the total HBV cccDNA. The total HBV viral

Ying Chen; Johnny Sze; Ming-Liang He

2004-01-01

324

Hydrological Forecasting in the Oder Estuary using a ThreeDimensional Hydrodynamic Model  

Microsoft Academic Search

A three-dimensional operational hydrodynamic model, developed at the Institute of Oceanography, University of Gda?sk was used to forecast hydrological conditions in the Oder Estuary. The model was based on the coastal ocean circulation model known as the Princeton Ocean Model (POM). Because of wind-driven water backup in the Oder mouth, a simplified operational model of river discharge, based on water

Halina Kowalewska-Kalkowska; Marek Kowalewski

2006-01-01

325

Hydrologic modelling for Lake Basaka: development and application of a conceptual water budget model.  

PubMed

Quantification of fluxes of water into and out of terminal lakes like Basaka has fundamental challenges. This is due to the fact that accurate measurement and quantification of most of the parameters of a lake's hydrologic cycle are difficult. Furthermore, quantitative understanding of the hydrologic systems and hence, the data-intensive modelling is difficult in developing countries like Ethiopia due to limitation of sufficient recorded data. Therefore, formulation of a conceptual water balance model is extremely important as it presents a convenient analytical tool with simplified assumptions to simulate the magnitude of unknown fluxes. In the current study, a conceptual lake water balance model was systematically formulated, solved, calibrated, and validated successfully. Then, the surface water and groundwater interaction was quantified, and a mathematical relationship developed. The overall agreement between the observed and simulated lake stage at monthly time step was confirmed based on the standard performance parameters (R(2), MAE, RMSE, E(f)). The result showed that hydrological water balance of the lake is dominated by the groundwater (GW) component. The net GW flux in recent period (post-2000s) accounts about 56% of the total water inflow. Hence, GW plays a leading role in the hydrodynamics and existence of Lake Basaka and is mostly responsible for the expansion of the lake. Thus, identification of the potential sources/causes for the GW flux plays a leading role in order to limit the further expansion of the lake. Measurement of GW movement and exchange in the area is a high priority for future research. PMID:24816590

Dinka, Megersa O; Loiskandl, Willibald; Ndambuki, Julius M

2014-09-01

326

eWaterCycle: Developing a hyper resolution global hydrological model  

NASA Astrophysics Data System (ADS)

The development of a high resolution global hydrological model has recently been put forward as Grand Challenge for the hydrological community (Wood et al., 2011). The eWaterCycle project aims at developing a high resolution global hydrological model allowing for a better representation of the effects of spatial heterogeneity in topography, soil, and vegetation on hydrological dynamics. The original version of the global hydrological model PCR-GLOBWB (van Beek et al., 2011) runs at a relatively coarse spatial grid (i.e. 0.5° or about 50 km at the equator), which is well below the hyper resolution envisioned in the Grand Challenge (i.e. 100 m). The development of such a hyper resolution model requires utilizing recent computational advances and massive parallel computer systems. So far, the hydrological community has not yet made full use of such possibilities. The eWaterCycle is a close cooperation between hydrologists (Delft University of Technology and Utrecht University) and the Netherlands eScience Center (NLeSC) - that intends to supports and reinforce data-intensive research through creative and innovative use of information and communication technology (ICT). In this project, we modify and extend PCR-GLOBWB so that it runs at much higher resolution, on the order of 1 km or finer. This model refinement is a huge step forward as increasing resolution also requires adding an explicit spatial representation of local processes (groundwater flow, water diversions, glaciers, etc.) that greatly enhance the regional to local applicability of the model. In this project, we also aim to run the model operationally with a data assimilation scheme that incorporates satellite soil moisture observations and other relevant variables. The outcome of the eWaterCycle project will be relevant for addressing critical water cycle science questions and hydrological applications such as assessing water resources sustainability, flood and drought frequency under climate change. For this session, we intend to share and discuss some first results of this novel hydrological model.

Drost, N.; Sutanudjaja, E.; Hut, R.; Steele-Dunne, S. C.; de Jong, K.; Van Beek, L. P.; Karssenberg, D.; Bierkens, M. F.; Van De Giesen, N.

2013-12-01

327

Predicting the natural flow regime: Models for assessing hydrological alteration in streams  

USGS Publications Warehouse

Understanding the extent to which natural streamflow characteristics have been altered is an important consideration for ecological assessments of streams. Assessing hydrologic condition requires that we quantify the attributes of the flow regime that would be expected in the absence of anthropogenic modifications. The objective of this study was to evaluate whether selected streamflow characteristics could be predicted at regional and national scales using geospatial data. Long-term, gaged river basins distributed throughout the contiguous US that had streamflow characteristics representing least disturbed or near pristine conditions were identified. Thirteen metrics of the magnitude, frequency, duration, timing and rate of change of streamflow were calculated using a 20-50 year period of record for each site. We used random forests (RF), a robust statistical modelling approach, to develop models that predicted the value for each streamflow metric using natural watershed characteristics. We compared the performance (i.e. bias and precision) of national- and regional-scale predictive models to that of models based on landscape classifications, including major river basins, ecoregions and hydrologic landscape regions (HLR). For all hydrologic metrics, landscape stratification models produced estimates that were less biased and more precise than a null model that accounted for no natural variability. Predictive models at the national and regional scale performed equally well, and substantially improved predictions of all hydrologic metrics relative to landscape stratification models. Prediction error rates ranged from 15 to 40%, but were 25% for most metrics. We selected three gaged, non-reference sites to illustrate how predictive models could be used to assess hydrologic condition. These examples show how the models accurately estimate predisturbance conditions and are sensitive to changes in streamflow variability associated with long-term land-use change. We also demonstrate how the models can be applied to predict expected natural flow characteristics at ungaged sites. ?? 2009 John Wiley & Sons, Ltd.

Carlisle, D.M.; Falcone, J.; Wolock, D.M.; Meador, M.R.; Norris, R.H.

2010-01-01

328

Integrating Satellite-Derived Snow Covered Area Information with a Hydrologic Forecast Model  

NASA Astrophysics Data System (ADS)

A NASA sponsored Regional Earth Science Application Center (RESAC) has been established to develop hydrologic modeling and analysis tools for operational management of water resources in the southwestern United States. An important component of the RESAC is development of methods to integrate satellite derived information about snow covered area (SCA) and station measurements of snow water equivalent with hydrologic models to improve forecasts of the amount and timing of runoff from mountain drainage basins. Images from satellite borne sensors with moderate spatial resolution and short revisit times can be used to produce frequent maps of snow cover. This satellite-derived information can be used to calibrate and validate model snow routines, and to initialize and update SCA during model runs. We have developed procedures to assimilate satellite-derived maps of SCA into a distributed hydrologic model. The Precipitation Runoff Modeling System, developed by the U.S. Geological Survey is used as the hydrologic model. Snowmaps produced by National Operational Hydrologic Remote Sensing Center of the National Weather Service at a resolution of 1km and temporal resolution of about a week are used to update initial model estimates of SCA. Basin runoff is then simulated based on these updated initial conditions. Runoff has been simulated for two high elevation, gauged headwater basins of the Gunnison River, a tributary of the Upper Colorado River, U.S.A. These basins present a challenge to modeling and snow mapping because a much of the basins areas are forested. Simulations of basin daily total runoff using model estimates of SCA and model estimates of SCA updated with satellite maps are compared with observed runoff.

Barrett, A. P.; Leavesley, G. H.; Hay, L. E.

2001-12-01

329

High resolution weather data for urban hydrological modelling and impact assessment, ICT requirements and future challenges  

NASA Astrophysics Data System (ADS)

Hydrological analysis of urban catchments requires high resolution rainfall and catchment information because of the small size of these catchments, high spatial variability of the urban fabric, fast runoff processes and related short response times. Rainfall information available from traditional radar and rain gauge networks does no not meet the relevant scales of urban hydrology. A new type of weather radars, based on X-band frequency and equipped with Doppler and dual polarimetry capabilities, promises to provide more accurate rainfall estimates at the spatial and temporal scales that are required for urban hydrological analysis. Recently, the RAINGAIN project was started to analyse the applicability of this new type of radars in the context of urban hydrological modelling. In this project, meteorologists and hydrologists work closely together in several stages of urban hydrological analysis: from the acquisition procedure of novel and high-end radar products to data acquisition and processing, rainfall data retrieval, hydrological event analysis and forecasting. The project comprises of four pilot locations with various characteristics of weather radar equipment, ground stations, urban hydrological systems, modelling approaches and requirements. Access to data processing and modelling software is handled in different ways in the pilots, depending on ownership and user context. Sharing of data and software among pilots and with the outside world is an ongoing topic of discussion. The availability of high resolution weather data augments requirements with respect to the resolution of hydrological models and input data. This has led to the development of fully distributed hydrological models, the implementation of which remains limited by the unavailability of hydrological input data. On the other hand, if models are to be used in flood forecasting, hydrological models need to be computationally efficient to enable fast responses to extreme event conditions. This presentation will highlight ICT-related requirements and limitations in high resolution urban hydrological modelling and analysis. Further ICT challenges arise in provision of high resolution radar data for diverging information needs as well as in combination with other data sources in the urban environment. Different types of information are required for such diverse activities as operational flood protection, traffic management, large event organisation, business planning in shopping districts and restaurants, timing of family activities. These different information needs may require different configurations and data processing for radars and other data sources. An ICT challenge is to develop techniques for deciding how to automatically respond to these diverging information needs (e.g., through (semi-)automated negotiation). Diverse activities also provide a wide variety of information resources that can supplement traditional networks of weather sensors, such as rain sensors on cars and social media. Another ICT challenge is how to combine data from these different sources for answering a particular information need. Examples will be presented of solutions are currently being explored.

ten Veldhuis, Marie-claire; van Riemsdijk, Birna

2013-04-01

330

On the dialog between experimentalist and modeler in catchment hydrology: Use of soft data for multicriteria model calibration  

Microsoft Academic Search

The dialog between experimentalist and modeler in catchment hydrology has been minimal to date. The experimentalist often has a highly detailed yet highly qualitative understanding of dominant runoff processes; thus there is often much more information content on the catchment than we use for calibration of a model. While modelers often appreciate the need for ``hard data'' for the model

Jan Seibert; Jeffrey J. McDonnell

2002-01-01

331

Flash flood prediction using an uncalibrated hydrological model and radar rainfall data in a Mediterranean watershed under changing hydrological conditions  

NASA Astrophysics Data System (ADS)

SummaryFlash floods cause some of the most severe natural disasters in Europe but Mediterranean areas are especially vulnerable. They can cause devastating damage to property, infrastructures and loss of human life. The complexity of flash flood generation processes and their dependency on different factors related to watershed properties and rainfall characteristics make flash flood prediction a difficult task. In this study, as part of the EU-FLASH project, we used an uncalibrated hydrological model to simulate flow events in a 27 km2 Mediterranean watershed in Israel to analyze and better understand the various factors influencing flows. The model is based on the well-known SCS curve number method for rainfall-runoff calculations and on the kinematic wave method for flow routing. Existing data available from maps, GIS and field studies were used to define model parameters, and no further calibration was conducted to obtain a better fit between computed and observed flow data. The model rainfall input was obtained from the high temporal and spatial resolution radar data adjusted to rain gauges. Twenty flow events that occurred within the study area over a 15 year period were analyzed. The model shows a generally good capability in predicting flash flood peak discharge in terms of their general level, classified as low, medium or high (all high level events were correctly predicted). It was found that the model mainly well predicts flash floods generated by intense, short-lived convective storm events while model performances for low and moderate flows generated by more widespread winter storms were quite poor. The degree of urban development was found to have a large impact on runoff amount and peak discharge, with higher sensitivity of moderate and low flow events relative to high flows. Flash flood generation was also found to be very sensitive to the temporal distribution of rain intensity within a specific storm event.

Rozalis, Shahar; Morin, Efrat; Yair, Yoav; Price, Colin

2010-11-01

332

Hydrological Validation of The Lpj Dynamic Global Vegetation Model - First Results and Required Actions  

NASA Astrophysics Data System (ADS)

Dynamic global vegetation models are developed with the main purpose to describe the spatio-temporal dynamics of vegetation at the global scale. Increasing concern about climate change impacts has put the focus of recent applications on the sim- ulation of the global carbon cycle. Water is a prime driver of biogeochemical and biophysical processes, thus an appropriate representation of the water cycle is crucial for their proper simulation. However, these models usually lack thorough validation of the water balance they produce. Here we present a hydrological validation of the current version of the LPJ (Lund- Potsdam-Jena) model, a dynamic global vegetation model operating at daily time steps. Long-term simulated runoff and evapotranspiration are compared to literature values, results from three global hydrological models, and discharge observations from various macroscale river basins. It was found that the seasonal and spatial patterns of the LPJ-simulated average values correspond well both with the measurements and the results from the stand-alone hy- drological models. However, a general underestimation of runoff occurs, which may be attributable to the low input dynamics of precipitation (equal distribution within a month), to the simulated vegetation pattern (potential vegetation without anthro- pogenic influence), and to some generalizations of the hydrological components in LPJ. Future research will focus on a better representation of the temporal variability of climate forcing, improved description of hydrological processes, and on the consider- ation of anthropogenic land use.

Haberlandt, U.; Gerten, D.; Schaphoff, S.; Lucht, W.

333

A common framework for the development and analysis of process-based hydrological models  

NASA Astrophysics Data System (ADS)

Building an environmental model requires making a series of decisions regarding the appropriate representation of natural processes. While some of these decisions can already be based on well-established physical understanding, gaps in our current understanding of environmental dynamics, combined with incomplete knowledge of properties and boundary conditions of most environmental systems, make many important modeling decisions far more ambiguous. There is consequently little agreement regarding what a "correct" model structure is, especially at relatively larger spatial scales such as catchments and beyond. In current practice, faced with such a range of decisions, different modelers will generally make different modeling decisions, often on an ad hoc basis, based on their balancing of process understanding, the data available to evaluate the model, the purpose of the modeling exercise, and other considerations. This presentation describes the application of the multiple-hypothesis methodology for developing and evaluating process-based hydrological models. Multiple-hypothesis methods provide a flexible (and extensible) approach to model development, including capabilities to 1) support multiple alternative decisions regarding process selection and representation; 2) accommodate different options for the model architecture, representing the connectivity between different model components; and 3) separate the hypothesized model equations from their solutions. Such flexibility in the selection of model architecture and components can be exploited to design various strategies for a controlled and thorough exploration of the hypothesis space, increasing the explanatory power of stringent model diagnostics that challenge both individual constituent hypotheses and the overall model architecture. Moreover, the availability of multiple modeling options improves representation of model uncertainty. In our application of multiple hypothesis methods in hydrology we seek to provide a common framework for model development and analysis. We recognize that the majority of process-based hydrological models use the same set of physics - most models use Darcy's Law to represent the flow of water through the soil matrix and Fourier's Law for thermodynamics. Our numerical model uses robust solutions of the hydrology and thermodynamic governing equations as the structural core, and incorporates multiple options to represent the impact of different modeling decisions, including different methods to represent spatial variability and different parameterizations of surface fluxes and shallow groundwater. Our analysis isolates individual modeling decisions and uses orthogonal diagnostic signatures to evaluate model behavior. Application of this framework in research basins demonstrates that the combination of (1) flexibility in the numerical model and (2) comprehensive scrutiny of orthogonal signatures provides a powerful approach to identify the suitability of different modeling options and different model parameter values. We contend that this common framework has general utility, and its widespread application in both research basins and at larger spatial scales will help accelerate the development of process-based hydrologic models.

Clark, Martyn; Kavetski, Dmitri; Fenicia, Fabrizio; Gupta, Hoshin

2013-04-01

334

Development of a Coupled Hydrological/Sediment Yield Model for a Watershed at Regional Level  

NASA Technical Reports Server (NTRS)

Development of a hydrologic model for the study of environmental conservation requires a comprehensive understanding of individual-storm affecting hydrologic and sedimentologic processes. The hydrologic models that we are currently coupling are the Simulator for Hydrology and Energy Exchange at the Land Surface (SHEELS) and the Distributed Runoff Model (DRUM). SHEELS runs continuously to estimate surface energy fluxes and sub-surface soil water fluxes, while DRUM operates during and following precipitation events to predict surface runoff and peak flow through channel routing. The lateral re-distribution of surface water determined by DRUM is passed to SHEELS, which then adjusts soil water contents throughout the profile. The model SHEELS is well documented in Smith et al. (1993) and Laymen and Crosson (1995). The model DRUM is well documented in Vieux et al. (1990) and Vieux and Gauer (1994). The coupled hydrologic model, SHEELS/DRUM, does not simulate sedimentologic processes. The simulation of the sedimentologic process is important for environmental conservation planning and management. Therefore, we attempted to develop a conceptual frame work for coupling a sediment yield model with SHEELS/DRUM to estimate individual-storm sediment yield from a watershed at a regional level. The sediment yield model that will be used for this study is the Universal Soil Loss Equation (USLE) with some modifications to enable the model to predict individual-storm sediment yield. The predicted sediment yield does not include wind erosion and erosion caused by irrigation and snow melt. Units used for this study are those given by Foster et al. (1981) for SI units.

Rajbhandaril, Narayan; Crosson, William; Tsegaye, Teferi; Coleman, Tommy; Liu, Yaping; Soman, Vishwas

1998-01-01

335

Hydrology of malaria: Model development and application to a Sahelian village  

NASA Astrophysics Data System (ADS)

We present a coupled hydrology and entomology model for the mechanistic simulation of local-scale response of malaria transmission to hydrological and climatological determinants in semiarid, desert fringe environments. The model is applied to the Sahel village of Banizoumbou, Niger, to predict interannual variability in malaria vector mosquito populations that lead to variations in malaria transmission. Using a high-resolution, small-scale distributed hydrology model that incorporates remotely sensed data for land cover and topography, we simulate the formation and persistence of the pools constituting the primary breeding habitat of Anopheles gambiae s.l. mosquitoes, the principal regional malaria vector mosquitoes. An agent-based mosquito population model is coupled to the distributed hydrology model, with aquatic-stage and adult-stage components. Through a dependence of aquatic-stage mosquito development and adult emergence on pool persistence, we model small-scale hydrology as a dominant control of mosquito abundance. For each individual adult mosquito, the model tracks attributes relevant to population dynamics and malaria transmission, which are updated as mosquitoes interact with their environment, humans, and animals. Weekly field observations were made in 2005 and 2006. A 16% increase in rainfall between the two years was accompanied by a 132% increase in mosquito abundance between 2005 and 2006. The model reproduces mosquito population variability at seasonal and interannual timescales and highlights individual pool persistence as a dominant control. Future developments of the presented model can be used in the evaluation of impacts of climate change on malaria, as well as the a priori evaluation of environmental management-based interventions.

Bomblies, Arne; Duchemin, Jean-Bernard; Eltahir, Elfatih A. B.

2008-12-01

336

The use of coupled atmospheric and hydrological models for water-resources management in headwater basins  

USGS Publications Warehouse

Coupled atmospheric and hydrological models provide an opportunity for the improved management of water resources in headwater basins. Issues currently limiting full implementation of coupled-model methodologies include (a) the degree of uncertainty in the accuracy of precipitation and other meteorological variables simulated by atmospheric models, and (b) the problem of discordant scales between atmospheric and bydrological models. Alternative methodologies being developed to address these issues are reviewed.

Leavesley, G.; Hay, L.

1998-01-01

337

Assessing agriculture–water links at the basin scale: hydrologic and economic models of the São Francisco River Basin, Brazil  

Microsoft Academic Search

This article uses a basin-wide hydrologic model to assess the hydrologic and economic effects of expanding agriculture in the São Francisco River Basin, Brazil. It then uses a basin-wide economic model of agriculture to examine the effects of implementing water use regulations. Preliminary results suggest that substantially expanding agriculture would put pressure on some of the river's environmental flows. Agricultural

Marco Maneta; Marcelo Torres; Stephen A. Vosti; Wesley W. Wallender; Summer Allen; Luís H. Bassoi; Lisa Bennett; Richard Howitt; Lineu Rodrigues; Julie Young

2009-01-01

338

Inverse Modeling of Hydrologic Parameters Using Surface Flux and Streamflow Observations in the Community Land Model  

NASA Astrophysics Data System (ADS)

This study aims at demonstrating the possibility of calibrating hydrologic parameters using surface flux and streamflow observations in version 4 of the Community Land Model (CLM4). Previously we showed that surface flux and streamflow calculations are sensitive to several key hydrologic parameters in CLM4, and discussed the necessity and possibility of parameter calibration. In this study, we evaluate performances of several different inversion strategies, including least-square fitting, quasi Monte-Carlo (QMC) sampling based Bayesian updating, and a Markov-Chain Monte-Carlo (MCMC) Bayesian inversion approach. The parameters to be calibrated include the surface and subsurface runoff generation parameters and vadose zone soil water parameters. We discuss the effects of surface flux and streamflow observations on the inversion results and compare their consistency and reliability using both monthly and daily observations at various flux tower and MOPEX sites. We find that the sampling-based stochastic inversion approaches behaved consistently - as more information comes in, the predictive intervals of the calibrated parameters as well as the misfits between the calculated and observed observations decrease. In general, the parameters that are identified to be significant through sensitivity analyses and statistical tests are better calibrated than those with weak or nonlinear impacts on flux or streamflow observations. We also evaluated the possibility of probabilistic model averaging for more consistent parameter estimation.

Sun, Y.; Hou, Z.; Huang, M.; Tian, F.; Leung, L.

2012-12-01

339

Hepatitis B virus (HBV) and autoimmune disease.  

PubMed

The etiology and pathogenesis of autoimmune diseases have long been an enigmatic subject that have involved genetic and environmental factors. Recent intriguing data has contributed to the mechanisms involved, including the relationship of infectious agents and loss of tolerance. This loss of tolerance is illustrated by the data on the immune response to Hepatitis B virus such as the molecular mimicry between HBV antigens and self proteins, the generation of immune complexes between HBV antigens and antibodies, and apoptosis/tissue damage resulting in the exposure of intracellular antigens to the immune system. In this paper, we review the current database related to HBV infection and a variety of autoimmune conditions, including autoimmune hepatitis, systemic lupus erythematosus, aplastic anemia, antiphospholipid syndrome, polyarteritis nodosa, rheumatoid arthritis, type 1 diabetes, multiple sclerosis, thyroid disease and uveitis. PMID:18270862

Maya, Ram; Gershwin, M Eric; Shoenfeld, Yehuda

2008-02-01

340

The clinical significance of occult HBV infection  

PubMed Central

The presence of hepatitis B virus (HBV) DNA in HBV surface antigen (HBsAg)-negative individuals is defined as occult HBV infection (OBI). OBI is related in some cases to infection with variant viruses (S-escape mutants) undetectable by HBsAg commercial kits. More frequently, however, it is due to infection with wild-type viruses that are strongly suppressed in their replication activity. OBI may be involved in different clinical contexts, including the transmission of the infection by blood transfusion or liver transplantation and its acute reactivation when an immunosuppressive status occurs. Moreover, much evidence suggests that it may contribute to the development of cirrhosis and may have an important role in hepatocarcinogenesis. PMID:24714731

Squadrito, Giovanni; Spinella, Rosaria; Raimondo, Giovanni

2014-01-01