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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

Modeling Runoff on the North Slope of Alaska Using the HBV Model  

Microsoft Academic Search

The Arctic fresh water hydrologic cycle is dominated by the melting of the seasonal snow cover and scattered precipitation events during the summer months. The HBV model has been applied in the Imnavait and Upper Kuparuk basins, located in the headwaters of the Kuparuk River on the North Slope, to examine runoff during spring and summer months. HBV is a

E. K. Youcha; E. Trochim; D. L. Kane

2007-01-01

4

Modeling Runoff on the North Slope of Alaska Using the HBV Model  

NASA Astrophysics Data System (ADS)

The Arctic fresh water hydrologic cycle is dominated by the melting of the seasonal snow cover and scattered precipitation events during the summer months. The HBV model has been applied in the Imnavait and Upper Kuparuk basins, located in the headwaters of the Kuparuk River on the North Slope, to examine runoff during spring and summer months. HBV is a semi-distributed conceptual model and was developed in 1975 by the Swedish Meteorological and Hydrological Institute. Simple data inputs and robust predictive capacity make HBV an attractive method for modeling discharge, particularly in basins with limited data. Current work has focused on calibrating the Imnaviat model with greater precision using historical meteorological and discharge data from 1988 to present. We are now developing new models for the larger Upper Kuparuk and Putuligayuk watersheds on the North Slope. Additional uses for the model include predicting discharge for ungaged North Slope basins east of the Kuparuk such as the Kadleroshilik and the Kavik. Parameter calibration initially begins with HBV-light, a scaled-down version of the model which is used to examine parameter sensitivity using a Monte Carlo procedure. Principle component analysis is then used to examine the interaction between the parameters and each year of the model run. An optimized set of parameters common to all calibrating years is developed and tested on additional data from gaged and ungaged basins. Existing research on ablation characteristics and precipitation correction is used to modify the associated parameters in HBV. Permafrost affects, such as the timing of active layer development, are integrated into the runoff response routine to produce a more accurate physical representation. Challenges associated with modeling larger watersheds include more spatially distributed processes and limited available data for model calibration.

Youcha, E. K.; Trochim, E.; Kane, D. L.

2007-12-01

5

Inhibition of hepatitis B virus (HBV) gene expression and replication by HBx gene silencing in a hydrodynamic injection mouse model with a new clone of HBV genotype B  

PubMed Central

Background It has been suggested that different hepatitis B virus (HBV) genotypes may have distinct virological characteristics that correlate with clinical outcomes during antiviral therapy and the natural course of infection. Hydrodynamic injection (HI) of HBV in the mouse model is a useful tool for study of HBV replication in vivo. However, only HBV genotype A has been used for studies with HI. Methods We constructed 3 replication-competent clones containing 1.1, 1.2 and 1.3 fold overlength of a HBV genotype B genome and tested them both in vitro and in vivo. Moreover, A HBV genotype B clone based on the pAAV-MCS vector was constructed with the 1.3 fold HBV genome, resulting in the plasmid pAAV-HBV1.3B and tested by HI in C57BL/6 mice. Application of siRNA against HBx gene was tested in HBV genotype B HI mouse model. Results The 1.3 fold HBV clone showed higher replication and gene expression than the 1.1 and 1.2 fold HBV clones. Compared with pAAV-HBV1.2 (genotype A), the mice HI with pAAV-HBV1.3B showed higher HBsAg and HBeAg expression as well as HBV DNA replication level but a higher clearance rate. Application of two plasmids pSB-HBxi285 and pSR-HBxi285 expressing a small/short interfering RNA (siRNA) to the HBx gene in HBV genotype B HI mouse model, leading to an inhibition of HBV gene expression and replication. However, HBV gene expression may resume in some mice despite an initial delay, suggesting that transient suppression of HBV replication by siRNA may be insufficient to prevent viral spread, particularly if the gene silencing is not highly effective. Conclusions Taken together, the HI mouse model with a HBV genotype B genome was successfully established and showed different characteristics in vivo compared with the genotype A genome. The effectiveness of gene silencing against HBx gene determines whether HBV replication may be sustainably inhibited by siRNA in vivo. PMID:23805945

2013-01-01

6

Assimilating H-SAF and MODIS Snow Cover Data into the Conceptual Models HBV and SRM  

NASA Astrophysics Data System (ADS)

Conceptual hydrological models are widely used for operational and scientific water resources management applications in mountain catchments. However, current model-based forecasting approaches are jeopardized by input data and model uncertainties. Data assimilation provides a suitable tool to merge information from remotely sensed observations and hydrological model predictions for improving the lead time performance of streamflow forecasts in the context of operational hydrological forecasting systems. In this study, we present a novel variational approach based on Moving Horizon Estimation (MHE). It includes a highly flexible formulation of distance metrics for penalizing the introduction of noise into the model and enforcing the agreement between simulated and observed variables. Furthermore, the MHE setup shows a high robustness regarding non-equidistant, noisy and sometimes missing data and enables the modification of model input as well as state variables. In situ snowpack measurements are sparsely distributed in mountainous regions. Therefore the data limitations in combination with snowpack heterogeneity prevent a detailed understanding of the variability of snow cover and melt. Remotely sensed images offer an opportunity to supplement ground measurements for performing runoff predictions during the snowmelt season. In this context, EUMETSAT initiated the H-SAF (Satellite Application Facility on Support to Operational Hydrology and Water Management) project for deriving novel products from satellite data and applying it to operational hydrology. This research contributes to the H-SAF product validation by applying a generic data assimilation test bed for H-SAF snow products in comparison to snow cover data of MODIS. A preliminary performance assessment of the data assimilation framework using the conceptual models HBV and SRM with satellite derived snow data is evaluated for a snow dominated test site of 10250 km2 at the headwaters of Euphrates River in Turkey.

Sensoy, Aynur; Schwanenberg, Dirk; Sorman, Arda; Akkol, Bulut; Alvarado Montero, Rodolfo; Uysal, Gokcen

2014-05-01

7

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

8

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

9

3, 36293653, 2006 Hydrological model  

E-print Network

HESSD 3, 3629­3653, 2006 Hydrological model coupling with ANNs R. G. Kamp and H. H. G. Savenije System Sciences Hydrological model coupling with ANNs R. G. Kamp 1,2 and H. H. G. Savenije 1 1 Section Correspondence to: R. G. Kamp (robert.kamp@mx-groep.nl) 3629 #12;HESSD 3, 3629­3653, 2006 Hydrological model

Boyer, Edmond

10

Hydrological models are mediating models  

NASA Astrophysics Data System (ADS)

Despite the increasing role of models in hydrological research and decision-making processes, only few accounts of the nature and function of models exist in hydrology. Earlier considerations have traditionally been conducted while making a clear distinction between physically-based and conceptual models. A new philosophical account, primarily based on the fields of physics and economics, transcends classes of models and scientific disciplines by considering models as "mediators" between theory and observations. The core of this approach lies in identifying models as (1) being only partially dependent on theory and observations, (2) integrating non-deductive elements in their construction, and (3) carrying the role of instruments of scientific enquiry about both theory and the world. The applicability of this approach to hydrology is evaluated in the present article. Three widely used hydrological models, each showing a different degree of apparent physicality, are confronted to the main characteristics of the "mediating models" concept. We argue that irrespective of their kind, hydrological models depend on both theory and observations, rather than merely on one of these two domains. Their construction is additionally involving a large number of miscellaneous, external ingredients, such as past experiences, model objectives, knowledge and preferences of the modeller, as well as hardware and software resources. We show that hydrological models convey the role of instruments in scientific practice by mediating between theory and the world. It results from these considerations that the traditional distinction between physically-based and conceptual models is necessarily too simplistic and refers at best to the stage at which theory and observations are steering model construction. The large variety of ingredients involved in model construction would deserve closer attention, for being rarely explicitly presented in peer-reviewed literature. We believe that devoting more importance to identifying and communicating on the many factors involved in model development might increase transparency of model building.

Babel, L. V.; Karssenberg, D.

2013-08-01

11

Thermal-hydrological models  

SciTech Connect

This chapter describes the physical processes and natural and engineered system conditions that affect thermal-hydrological (T-H) behavior in the unsaturated zone (UZ) at Yucca Mountain and how these effects are represented in mathematical and numerical models that are used to predict T-H conditions in the near field, altered zone, and engineered barrier system (EBS), and on waste package (WP) surfaces.

Buscheck, T., LLNL

1998-04-29

12

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

13

Understanding the molecular basis of HBV drug resistance by molecular modeling.  

PubMed

Despite the significant successes in the area of anti-HBV agents, resistance and cross-resistance against available therapeutics are the major hurdles in drug discovery. The present investigation is to understand the molecular basis of drug resistance conferred by the B and C domain mutations of HBV-polymerase on the binding affinity of five anti-HBV agents [lamivudine (3TC, 1), adefovir (ADV, 2), entecavir (ETV, 3), telbivudine (LdT, 4) and clevudine (l-FMAU, 5)]. In this regard, homology modeled structure of HBV-polymerase was used for minimization, conformational search and induced fit docking followed by binding energy calculation on wild-type as well as on mutant HBV-polymerases (L180M, M204V, M204I, L180M+M204V, L180M-M204I). Our studies suggest a significant correlation between the fold resistances and the binding affinity of anti-HBV nucleosides. The binding mode studies reveals that the domain C residue M204 is closely associated with sugar/pseudosugar ring positioning in the active site. The positioning of oxathiolane ring of 3TC (1) is plausible due the induced fit orientation of the M204 residue in wild-type, and further mutation of M204 to V204 or I204 reduces the final binding affinity which leads to the drug resistance. The domain B residue L180 is not directly close ( approximately 6A) to the nucleoside/nucleoside analogs, but indirectly associated with other active-site hydrophobic residues such as A87, F88, P177 and M204. These five hydrophobic residues can directly affect on the incoming nucleoside analogs in terms of its association and interaction that can alter the final binding affinity. There was no sugar ring shifting observed in the case of adefovir (2) and entecavir (3), and the position of sugar ring of 2 and 3 is found similar to the sugar position of natural substrate dATP and dGTP, respectively. The exocyclic double bond of entecavir (3) occupied in the backside hydrophobic pocket (made by residues A87, F88, P177, L180 and M204), which enhances the overall binding affinity. The active site binding of LdT (4) and l-FMAU (5) showed backward shifting along with upward movement without enforcing M204 residue and this significant different binding mode makes these molecules as polymerase inhibitors, without being incorporated into the growing HBV-DNA chain. Structural results conferred by these l- and d-nucleosides, explored the molecular basis of drug resistance which can be utilized for future anti-HBV drug discovery. PMID:18765256

Sharon, Ashoke; Chu, Chung K

2008-12-01

14

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

15

Toll-like receptor 4 plays an anti-HBV role in a murine model of acute hepatitis B virus expression  

PubMed Central

AIM: Toll-like receptor 4 (TLR4) has been shown to be important for bacterial infection, especially to lipopolysaccharide signaling. Its possible role in HBV infection is studied in the present study. MATERIALS AND METHODS: pHBV3.6 plasmid, containing full-length HBV genome was used in the murine model of acute HBV expression by hydrodynamics in vivo transfection. TLR4 normal or mutant mouse strain was compared to investigate the possible role of TLR4 in acute HBV expression. RESULTS: After pHBV3.6 injection, the infiltrating leukocytes expressed TLR4 were observed nearby the HBsAg-expressing hepatocytes. The HBV antigenemia as well as the replication and transcription were higher in TLR4-mutant C3H/HeJ mice than in normal C3H/HeN mice. The HBV-specific immune responses were impaired in the liver or spleen of the C3H/HeJ mice. Their inducible nitric oxide synthase (iNOS) expression on the hepatic infiltrating cells was also impaired. When adoptively transferring splenocytes from C3H/HeN mice to C3H/HeJ mice, the HBV replication was inhibited to the level as that of C3H/HeN. CONCLUSION: These results suggest that TLR4 plays an anti-HBV role in vivo through the induction of iNOS expression and HBV-specific immune responses after HBV expression. PMID:16425356

Chang, Wen-Wei; Su, Ih-Jen; Lai, Ming-Derg; Chang, Wen-Tsan; Huang, Wenya; Lei, Huan-Yao

2005-01-01

16

Effect of Trichinella spiralis infection on the immune response to HBV vaccine in a mouse model.  

PubMed

Vaccination is the most effective and cost-effective way to treat hepatitis B virus (HBV) infection. Collective data suggest that helminth infections affect immune responses to some vaccines. Therefore, it is important to reveal the effects of helminth infections on the efficacy of protective vaccines in countries with highly prevalent helminth infections. In the present work, effects of Trichinella spiralis infection on the protective efficacy of HBV vaccine in a mouse model were investigated. This study demonstrated that the enteric stage of T. spiralis infection could inhibit the proliferative response of spleen lymphocytes to hepatitis B surface antigen (HBsAg) and lead to lower levels of anti-HBsAg antibodies, interferon-?, and interleukin (IL)-2, along with higher levels of IL-4 and IL-5. However, these immunological differences are absent in the muscle stage of T. spiralis infection. The results suggest that the muscle stage of T. spiralis infection does not affect the immune response to HBV vaccination, while the enteric-stage infection results in a reduced immune response to HBsAg. PMID:23883369

Guan, Fei; Hou, Xiao; Nie, Ge; Xiao, Yan; Zhang, Qi; Liu, Wen-qi; Li, Yong-long; Lei, Jia-hui

2013-10-01

17

Ensemble stream flow predictions, a way towards better hydrological forecasting  

Microsoft Academic Search

The hydrological forecasting division at SMHI has been using hydrological EPS and hydrological probabilities forecasts operationally since some years ago. The inputs to the hydrological model HBV are the EPS forecasts from ECMWF. From the ensemble, non-exceedance probabilities are estimated and final correction of the ensemble spread, based on evaluation is done. Ensemble stream flow predictions are done for about

C. Edlund

2009-01-01

18

Importance of temporal and spatial resolution on modelling hydrological extremes in a small catchment  

NASA Astrophysics Data System (ADS)

Under the conditions of changing climate the more frequent extremes in hydrological regime are expected. For the small watershed management it is therefore of big interest what the possible range of these changes could be, since it is essential for design of appropriate mitigation measures. An exemplary case study of possible impacts of the climate change was carried out. The conceptual model HBV was applied in a small hilly pre-alpine Rietholzbach catchment with the aim to assess the frequency and magnitude of hydrological extremes under different climatic conditions. The effect of the time and spatial distribution on the model output characteristics was also investigated. For impact evaluation a conceptual lumped model HBV was chosen because of its robustness, easy applicability for long-term simulations and perceptually straight-forward parameters. Two different modelling approaches were used, in the first one the catchment of interest was treated as a lumped system and in the other where it was divided into several subcatchments. As a first step HBV was applied to the historical data set to evaluate his performance and suitability for hydrological predictions. One half of the data time-series was used for HBV parameter calibration, the other one for model validation, wherefore several objective functions were used for goodness of fit evaluation. In order to obtain the range of changes in hydrological characteristics which can be expected due to the changing climate, two extreme scenarios were then applied to the catchment model. A standard daily step was used to obtain data for water balance and long-term droughts analysis and a study of applicability of the model with the hourly computational step was performed, so that occurrance of maximum discharges could be evaluated. The poster presents the model outcomes with focus on flood and long-drought characteristics. The uncertainty of the impacts is illustrated by the range of characteristics obtained from different climatic scenarios, spatial resolution of the model and considers the model reliability as well.

Strouhal, L.; Seibert, J.; David, V.

2012-04-01

19

Stochastic Modelling of Hydrologic Systems  

E-print Network

are to be used for automatic control in the waste water treatment plant. The conditional parametric modellingStochastic Modelling of Hydrologic Systems Harpa Jonsdottir Kongens Lyngby 2006 IMM-PHD-2006 to stiff systems. The system in one of the papers is stiff. In Paper [A] a conditional parametric modelling

20

Model Calibration in Watershed Hydrology  

NASA Technical Reports Server (NTRS)

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 as model calibration, the parameters are adjusted so that the behavior of the model approximates, as closely and consistently as possible, the observed response of the hydrologic system over some historical period of time. This Chapter reviews the current state-of-the-art of model calibration in watershed hydrology with special emphasis on our own contributions in the last few decades. We discuss the historical background that has led to current perspectives, and review different approaches for manual and automatic single- and multi-objective parameter estimation. In particular, we highlight the recent developments in the calibration of distributed hydrologic models using parameter dimensionality reduction sampling, parameter regularization and parallel computing.

Yilmaz, Koray K.; Vrugt, Jasper A.; Gupta, Hoshin V.; Sorooshian, Soroosh

2009-01-01

21

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

22

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

23

Environmental Observatories and Hydrologic Modeling  

NASA Astrophysics Data System (ADS)

During the past several years, the environmental sciences community has been attempting to design large- scale obsevatories that will transform the science. A watershed-based observatory has emerged as an effective landscape unit for a broad range of environmental sciences and engineering. For an effective observatory, modeling is a central requirement because models are precise statements of the hypothesized conceptual organization of watersheds and of the processes believed to be controlling hydrology of the watershed. Furthermore, models can serve to determine the value of existing data and the incremental value of any additional data to be collected. Given limited resources, such valuation is mandatory for an objective design of an observatory. Modeling is one part of a "digital watershed" that must be constructed for any observatory, a concept that has been developed by the CUAHSI Hydrologic Information Systems project. A digital watershed has three functions. First, it permits assembly of time series (such as stream discharge or precipitation measurements), static spatial coverages (such as topography), and dynamic fields (such as precipitation radar and other remotely sensed data). Second, based upon this common data description, a digital observatory permits multiple conceptualizations of the observatory to be created and to be stored. These conceptualizations could range from lumped box-and-arrow watershed models, to semi-distributed topographically based models, to three-dimensional finite element models. Finally, each conceptualization can lead to multiple models--that is, a set of equations that quantitatively describe hydrologic (or biogeochemical or geomorphologic) processes through libraries of tools that can be linked as workflow sequences. The advances in cyberinfrastructure that allow the storage of multiple conceptualizations and multiple model formulations of these conceptualizations promise to accelerate advances in environmental science both by permitting greater efficiency in modeling but, more importantly, by permitting a deeper exchange of ideas among scientists from multiple disciplines.

Hooper, R. P.; Duncan, J. M.

2006-12-01

24

Committee of machine learning predictors of hydrological models uncertainty  

NASA Astrophysics Data System (ADS)

In prediction of uncertainty based on machine learning methods, the results of various sampling schemes namely, Monte Carlo sampling (MCS), generalized likelihood uncertainty estimation (GLUE), Markov chain Monte Carlo (MCMC), shuffled complex evolution metropolis algorithm (SCEMUA), differential evolution adaptive metropolis (DREAM), particle swarm optimization (PSO) and adaptive cluster covering (ACCO)[1] used to build a predictive models. These models predict the uncertainty (quantiles of pdf) of a deterministic output from hydrological model [2]. Inputs to these models are the specially identified representative variables (past events precipitation and flows). The trained machine learning models are then employed to predict the model output uncertainty which is specific for the new input data. For each sampling scheme three machine learning methods namely, artificial neural networks, model tree, locally weighted regression are applied to predict output uncertainties. The problem here is that different sampling algorithms result in different data sets used to train different machine learning models which leads to several models (21 predictive uncertainty models). There is no clear evidence which model is the best since there is no basis for comparison. A solution could be to form a committee of all models and to sue a dynamic averaging scheme to generate the final output [3]. This approach is applied to estimate uncertainty of streamflows simulation from a conceptual hydrological model HBV in the Nzoia catchment in Kenya. [1] N. Kayastha, D. L. Shrestha and D. P. Solomatine. Experiments with several methods of parameter uncertainty estimation in hydrological modeling. Proc. 9th Intern. Conf. on Hydroinformatics, Tianjin, China, September 2010. [2] D. L. Shrestha, N. Kayastha, and D. P. Solomatine, and R. Price. Encapsulation of parameteric uncertainty statistics by various predictive machine learning models: MLUE method, Journal of Hydroinformatic, in press, 2013. [3] N., Kayastha, J. Ye, F. Fenicia, V. Kuzmin, and D. P. Solomatine. Fuzzy committees of specialized rainfall-runoff models: further enhancements and tests. Hydrol. Earth Syst. Sci., 17, 4441-4451, 2013

Kayastha, Nagendra; Solomatine, Dimitri

2014-05-01

25

MODEL ABSTRACTION IN HYDROLOGIC MODELING  

Technology Transfer Automated Retrieval System (TEKTRAN)

Model abstraction (MA) is a methodology for reducing the complexity of a simulation model while maintaining the validity of the simulation results with respect to the question that the simulation is being used to address. The MA explicitly deals with uncertainties in model structure and in model par...

26

When are multiobjective calibration trade-offs in hydrologic models meaningful?  

NASA Astrophysics Data System (ADS)

This paper applies a four-objective calibration strategy focusing on peak flows, low flows, water balance, and flashiness to 392 model parameter estimation experiment (MOPEX) watersheds across the United States. Our analysis explores the influence of model structure by analyzing how the multiobjective calibration trade-offs for two conceptual hydrologic models, the Hydrology Model (HYMOD) and the Hydrologiska Byråns Vattenbalansavdelning (HBV) model, compare for each of the 392 catchments. Our results demonstrate that for modern multiobjective calibration frameworks to identify any meaningful measure of model structural failure, users must be able to carefully control the precision by which they evaluate their trade-offs. Our study demonstrates that the concept of epsilon-dominance provides an effective means of attaining bounded and meaningful hydrologic model calibration trade-offs. When analyzed at an appropriate precision, we found that meaningful multiobjective trade-offs are far less frequent than prior literature has suggested. However, when trade-offs do exist at a meaningful precision, they have significant value for supporting hydrologic model selection, distinguishing core model deficiencies, and identifying hydroclimatic regions where hydrologic model prediction is highly challenging.

Kollat, J. B.; Reed, P. M.; Wagener, T.

2012-03-01

27

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

28

Hydrologic Modeling of Boreal Forest Ecosystems  

NASA Technical Reports Server (NTRS)

This study focused on the hydrologic response, including vegetation water use, of two test regions within the Boreal-Ecosystem-Atmosphere Study (BOREAS) region in the Canadian boreal forest, one north of Prince Albert, Saskatchewan, and the other near Thompson, Manitoba. Fluxes of moisture and heat were studied using a spatially distributed hydrology soil-vegetation-model (DHSVM).

Haddeland, I.; Lettenmaier, D. P.

1995-01-01

29

Hepatitis B (HBV)  

MedlinePLUS

... for Kids for Teens Teens Home Body Mind Sexual Health Food & Fitness Diseases & Conditions Infections Q&A School & ... Dealing With Anger Hepatitis B (HBV) KidsHealth > Teens > Sexual Health > STDs & Other Infections > Hepatitis B (HBV) Print A ...

30

Impacts of Operator Order in Hydrological Models  

NASA Astrophysics Data System (ADS)

Operator-Splitting errors are inherent in many hydrological models and can lead to computational inefficiencies, parameter estimation issues and inaccurate model results. A detailed study of the operator splitting errors produced by standard implementations of VIC and TOPMODEL has been performed both to assess their significance and to evaluate methods to correct them. Both VIC and TOPMODEL have been incorporated into RAVEN, an object-oriented hydrological model developed at the University of Waterloo. RAVEN has been developed to model hydrological processes using flexible numerical algorithms. RAVEN's structure is specifically designed to separate the numerical methods from the conceptual design to provide flexibility and to allow a separation of the numerics from the physical representations. The advantages of this numerical and conceptual separation has led to a better understanding of the impacts that operator splitting has on existing hydrological models and has allowed for improvements within models that increase accuracy and minimize errors.

Snowdon, A. P.; Craig, J. R.

2009-05-01

31

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

32

Hydrologic Models for Inverse Climate Change Impact Modeling  

Microsoft Academic Search

It is expected that the global climate change will have significant impacts on the regime of hydrologic extremes. As a consequence, the design and management of water resource systems will have to adapt to the changing hydrologic extremes. An inverse approach to the modeling of hydrologic risk and vulnerability to changing climatic conditions was developed in this project to improve

Juraj M. Cunderlik; Slobodan P. Simonovic

33

Quantile hydrologic model selection and uncertainty assessment  

NASA Astrophysics Data System (ADS)

Inapplicability of state of the art hydrological models due to scarce data motivates the need for a modeling approach that can be well constrained to available data and still model dominant processes. Such an approach requires embedded model relationships to be simple and parsimonious in parameters for robust model selection. Simplicity in functional relationship is also important from water management point of view if these models are to be coupled with economic system models for meaningful policy assessment. We propose a semi-distributed approach wherein we model already known dominant processes in dryland areas of Western India (evaporation, Hortonian overland flows, transmission loses and subsurface flows) in a simple but constrained manner through mathematical programming of relevant equations and constraints. Diverse data sources such as GRACE, MERRA reanalysis data, FAO soil texture map and even Indian Agricultural Census data are used. Such a modeling approach allows uncertainty quantification through quantile parameter estimation, which we present in this talk. Quantile estimation transfers uncertainty due to hydrologic model misspecification or data uncertainty, based on quantiles of residuals, onto parameters of the hydrologic model with a fixed structure. An adaptation of quantile regression to parsimonious hydrologic model estimation, this frequentist approach seeks to complement existing Bayesian approaches to model parameter and prediction uncertainty.

Pande, S.; Keyzer, M. A.; Savenije, H.; Gosain, A. K.

2010-12-01

34

Uncertainty in hydrologic modeling: Toward an integrated data assimilation framework  

Microsoft Academic Search

Despite significant recent developments in computational power and distributed hydrologic modeling, the issue of how to adequately address the uncertainty associated with hydrological predictions remains a critical and challenging one. This issue needs to be properly addressed for hydrological modeling to realize its maximum practical potential in environmental decision-making processes. Arguably, the key to properly addressing hydrologic uncertainty is to

Yuqiong Liu; Hoshin V. Gupta

2007-01-01

35

Evaluation of statistical models for forecast errors from the HBV model  

NASA Astrophysics Data System (ADS)

SummaryThree statistical models for the forecast errors for inflow into the Langvatn reservoir in Northern Norway have been constructed and tested according to the agreement between (i) the forecast distribution and the observations and (ii) median values of the forecast distribution and the observations. For the first model observed and forecasted inflows were transformed by the Box-Cox transformation before a first order auto-regressive model was constructed for the forecast errors. The parameters were conditioned on weather classes. In the second model the Normal Quantile Transformation (NQT) was applied on observed and forecasted inflows before a similar first order auto-regressive model was constructed for the forecast errors. For the third model positive and negative errors were modeled separately. The errors were first NQT-transformed before conditioning the mean error values on climate, forecasted inflow and yesterday's error. To test the three models we applied three criterions: we wanted (a) the forecast distribution to be reliable; (b) the forecast intervals to be narrow; (c) the median values of the forecast distribution to be close to the observed values. Models 1 and 2 gave almost identical results. The median values improved the forecast with Nash-Sutcliffe R eff increasing from 0.77 for the original forecast to 0.87 for the corrected forecasts. Models 1 and 2 over-estimated the forecast intervals but gave the narrowest intervals. Their main drawback was that the distributions are less reliable than Model 3. For Model 3 the median values did not fit well since the auto-correlation was not accounted for. Since Model 3 did not benefit from the potential variance reduction that lies in bias estimation and removal it gave on average wider forecasts intervals than the two other models. At the same time Model 3 on average slightly under-estimated the forecast intervals, probably explained by the use of average measures to evaluate the fit.

Engeland, Kolbjørn; Renard, Benjamin; Steinsland, Ingelin; Kolberg, Sjur

2010-04-01

36

Evaluation Of Statistical Models For Forecast Errors From The HBV-Model  

NASA Astrophysics Data System (ADS)

Three statistical models for the forecast errors for inflow to the Langvatn reservoir in Northern Norway have been constructed and tested according to how well the distribution and median values of the forecasts errors fit to the observations. For the first model observed and forecasted inflows were transformed by the Box-Cox transformation before a first order autoregressive model was constructed for the forecast errors. The parameters were conditioned on climatic conditions. In the second model the Normal Quantile Transformation (NQT) was applied on observed and forecasted inflows before a similar first order autoregressive model was constructed for the forecast errors. For the last model positive and negative errors were modeled separately. The errors were first NQT-transformed before a model where the mean values were conditioned on climate, forecasted inflow and yesterday's error. To test the three models we applied three criterions: We wanted a) the median values to be close to the observed values; b) the forecast intervals to be narrow; c) the distribution to be correct. The results showed that it is difficult to obtain a correct model for the forecast errors, and that the main challenge is to account for the auto-correlation in the errors. Model 1 and 2 gave similar results, and the main drawback is that the distributions are not correct. The 95% forecast intervals were well identified, but smaller forecast intervals were over-estimated, and larger intervals were under-estimated. Model 3 gave a distribution that fits better, but the median values do not fit well since the auto-correlation is not properly accounted for. If the 95% forecast interval is of interest, Model 2 is recommended. If the whole distribution is of interest, Model 3 is recommended.

Engeland, K.; Kolberg, S.; Renard, B.; Stensland, I.

2009-04-01

37

Balancing model complexity and measurements in hydrology  

NASA Astrophysics Data System (ADS)

The Data Processing Inequality implies that hydrological modeling can only reduce, and never increase, the amount of information available in the original data used to formulate and calibrate hydrological models: I(X;Z(Y)) ? I(X;Y). Still, hydrologists around the world seem quite content building models for "their" watersheds to move our discipline forward. Hydrological models tend to have a hybrid character with respect to underlying physics. Most models make use of some well established physical principles, such as mass and energy balances. One could argue that such principles are based on many observations, and therefore add data. These physical principles, however, are applied to hydrological models that often contain concepts that have no direct counterpart in the observable physical universe, such as "buckets" or "reservoirs" that fill up and empty out over time. These not-so-physical concepts are more like the Artificial Neural Networks and Support Vector Machines of the Artificial Intelligence (AI) community. Within AI, one quickly came to the realization that by increasing model complexity, one could basically fit any dataset but that complexity should be controlled in order to be able to predict unseen events. The more data are available to train or calibrate the model, the more complex it can be. Many complexity control approaches exist in AI, with Solomonoff inductive inference being one of the first formal approaches, the Akaike Information Criterion the most popular, and Statistical Learning Theory arguably being the most comprehensive practical approach. In hydrology, complexity control has hardly been used so far. There are a number of reasons for that lack of interest, the more valid ones of which will be presented during the presentation. For starters, there are no readily available complexity measures for our models. Second, some unrealistic simplifications of the underlying complex physics tend to have a smoothing effect on possible model outcomes, thereby preventing the most obvious results of over-fitting. Thirdly, dependence within and between time series poses an additional analytical problem. Finally, there are arguments to be made that the often discussed "equifinality" in hydrological models is simply a different manifestation of the lack of complexity control. In turn, this points toward a general idea, which is actually quite popular in sciences other than hydrology, that additional data gathering is a good way to increase the information content of our descriptions of hydrological reality.

Van De Giesen, N.; Schoups, G.; Weijs, S. V.

2012-12-01

38

Hydrological Distributed Model for Flash Flood  

E-print Network

parameters, soil texture, soil erodibility LAND USE / LAND COVER: roughness coefficient, interception depth Julien, PY; Saghafian, B. 1991. CASC2D Users Manual - A Two Dimensional Watershed Rainfall-Runoff Model; Saghafian, B; Ogden, FL. 1995. Raster-Based Hydrologic Modeling of Spatially- Varied Surface Runoff. Water

Julien, Pierre Y.

39

Multi-criteria evaluation of hydrological models  

NASA Astrophysics Data System (ADS)

Over the last years, there is a tendency in the hydrological community to move from the simple conceptual models towards more complex, physically/process-based hydrological models. This is because conceptual models often fail to simulate the dynamics of the observations. However, there is little agreement on how much complexity needs to be considered within the complex process-based models. One way to proceed to is to improve understanding of what is important and unimportant in the models considered. The aim of this ongoing study is to evaluate structural model adequacy using alternative conceptual and process-based models of hydrological systems, with an emphasis on understanding how model complexity relates to observed hydrological processes. Some of the models require considerable execution time and the computationally frugal sensitivity analysis, model calibration and uncertainty quantification methods are well-suited to providing important insights for models with lengthy execution times. The current experiment evaluates two version of the Framework for Understanding Structural Errors (FUSE), which both enable running model inter-comparison experiments. One supports computationally efficient conceptual models, and the second supports more-process-based models that tend to have longer execution times. The conceptual FUSE combines components of 4 existing conceptual hydrological models. The process-based framework consists of different forms of Richard's equations, numerical solutions, groundwater parameterizations and hydraulic conductivity distribution. The hydrological analysis of the model processes has evolved from focusing only on simulated runoff (final model output), to also including other criteria such as soil moisture and groundwater levels. Parameter importance and associated structural importance are evaluated using different types of sensitivity analyses techniques, making use of both robust global methods (e.g. Sobol') as well as several alternative local sensitivity analysis methods. The latter methods can yield similar results, however they are much more computationally frugal than the global methods and often are better suited to analysis of complex models. Simple models are used to compare the global and local methods, and insights used to interpret results for complex model for which the local methods are much more convenient. The analyses are carried out for a medium-sized catchment (200 km2) in the Belgian Ardennes, for which meteorological, fluxnet data, in situ soil moisture and groundwater time series are available.

Rakovec, Oldrich; Clark, Martyn; Weerts, Albrecht; Hill, Mary; Teuling, Ryan; Uijlenhoet, Remko

2013-04-01

40

Approaches to modelling hydrology and ecosystem interactions  

NASA Astrophysics Data System (ADS)

As the pressures of industry, agriculture and mining on groundwater resources increase there is a burgeoning un-met need to be able to capture these multiple, direct and indirect stresses in a formal framework that will enable better assessment of impact scenarios. While there are many catchment hydrological models and there are some models that represent ecological states and change (e.g. FLAMES, Liedloff and Cook, 2007), these have not been linked in any deterministic or substantive way. Without such coupled eco-hydrological models quantitative assessments of impacts from water use intensification on water dependent ecosystems under changing climate are difficult, if not impossible. The concept would include facility for direct and indirect water related stresses that may develop around mining and well operations, climate stresses, such as rainfall and temperature, biological stresses, such as diseases and invasive species, and competition such as encroachment from other competing land uses. Indirect water impacts could be, for example, a change in groundwater conditions has an impact on stream flow regime, and hence aquatic ecosystems. This paper reviews previous work examining models combining ecology and hydrology with a view to developing a conceptual framework linking a biophysically defensable model that combines ecosystem function with hydrology. The objective is to develop a model capable of representing the cumulative impact of multiple stresses on water resources and associated ecosystem function.

Silberstein, Richard P.

2014-05-01

41

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

42

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

43

Models capture hydrological processes in coastal environments  

NASA Astrophysics Data System (ADS)

It is inherently difficult, if not impossible, to observe and make adequate measurement of certain types of natural processes. For instance, whether it is the formation of landscapes, such as deltas, or fine-scale processes, such as the transport of fluids and solutes, water flowing over surfaces has presented major challenges for scientists interested in studying hydrologic processes occurring at the interface of the surface and flowing water. Although researchers have relied on numerical models to simulate hydrological processes that operate along a sediment-water interface, the method has been criticized for not being verified by in situ observations. However, new research shows that numerical simulations based on fluid dynamical properties do broadly mimic hydrological processes at the sediment and flowing water interface, at least in systems where water flows over, below, or adjacent to porous sedimentary surfaces, such as in coastal marine environments.

Bhattacharya, Atreyee

2012-10-01

44

Watershed, Climate, Hydrology Modeling Joint Projects of  

E-print Network

of Agriculture & Home EconomicsCollege of Agriculture & Home Economics ­­ WaterWater Task ForceTask ForceWatershed, Climate, Hydrology Modeling Joint Projects of NMSU Water Task Force and Center for Applied Remote Sensing in Agriculture, Meteorology, and Environment #12;Purpose A cooperative effort

45

Catchment classification by means of hydrological models  

NASA Astrophysics Data System (ADS)

An important hydrological objective is catchment classification that will serve as a basis for the regionalisation of discharge parameters or model parameters. The main task of this study is the development and assessment of two classification approaches with respect to their efficiency in catchment classification. The study area in western Germany comprises about 80 catchments that range in size from 8 km2 up to 1500 km2, covering a wide range of geological substrata, soils, landscapes and mean annual precipitation. In a first approach Self Organising Maps (SOMs) use discharge characteristics or catchment characteristics to classify the catchments of the study area. Next, a reference hydrological model calibrates the catchments of the study area and tests the possibilities of parameter transfer. Compared to the transfer of parameters outside a class, for most catchments the model performance improves when parameters within a class are transferred. Thus, it should be possible to distinguish catchment classes by means of a hydrological model. The classification results of the SOM are compared to the classification results of the reference hydrological model in order to determine the latter validity. The second approach builds on the first approach in such a way that it uses the Superflex Modelling Framework instead of only one reference model. Within this framework multiple conceptual model structures can be calibrated and adapted. Input data for each calibration of a catchment are hourly time series of runoff, precipitation and evaporation for at least eight years. The calibration of multiple models for each catchment and their comparison allows for the assessment of the influence of different model structures on model performance. Learning loops analyse model performance and adapt model structures accordingly with a view to performance improvement. The result of the modelling exercise is a best performing model structure for each catchment that serves as a basis for catchment description and clustering. Hence, the classes do not only represent a distinctive hydrological regime, but also provide information on specific quantitative aspects that are directly linked to a certain model structure. The clustering that is based on model structures or model parameters are validated by the classifications based on SOM and are thus related to physiographic and climatic catchment properties and runoff behaviour, which provides insight into catchment functioning. Clustering based on model structures can be a fast and simple way of catchment classification. A database consistently relates input data and output data; model structures and model performance and allows formulating distinctive processes that are attached to a class. Thus, the final result of the study is a powerful classification tool that helps to formulate generalizations based on observations and testable hypotheses (i.e. model structures).

Hellebrand, Hugo; Ley, Rita; Casper, Markus

2013-04-01

46

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

47

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 of neglecting rainfall spatial variability for runoff modelling at the outlet of catchments of about ten to several hundred km². In order to overcome modelling and rainfall data errors, to control the rainfall

Paris-Sud XI, Université de

48

Integration of stream and watershed data for hydrologic modeling  

E-print Network

This thesis presents the development of a hydrologic model in the vector environment. Establishing spatial relationship between flow elements is the key for flow routing techniques. Such a relationship is called hydrologic topology, making each flow...

Koka, Srikanth

2004-09-30

49

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

50

Grid based calibration of SWAT hydrological models  

NASA Astrophysics Data System (ADS)

The calibration and execution of large hydrological models, such as SWAT (soil and water assessment tool), developed for large areas, high resolution, and huge input data, need not only quite a long execution time but also high computation resources. SWAT hydrological model supports studies and predictions of the impact of land management practices on water, sediment, and agricultural chemical yields in complex watersheds. The paper presents the gSWAT application as a web practical solution for environmental specialists to calibrate extensive hydrological models and to run scenarios, by hiding the complex control of processes and heterogeneous resources across the grid based high computation infrastructure. The paper highlights the basic functionalities of the gSWAT platform, and the features of the graphical user interface. The presentation is concerned with the development of working sessions, interactive control of calibration, direct and basic editing of parameters, process monitoring, and graphical and interactive visualization of the results. The experiments performed on different SWAT models and the obtained results argue the benefits brought by the grid parallel and distributed environment as a solution for the processing platform. All the instances of SWAT models used in the reported experiments have been developed through the enviroGRIDS project, targeting the Black Sea catchment area.

Gorgan, D.; Bacu, V.; Mihon, D.; Rodila, D.; Abbaspour, K.; Rouholahnejad, E.

2012-07-01

51

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

52

Use of different sampling schemes in machine learning-based prediction of hydrological models' uncertainty  

NASA Astrophysics Data System (ADS)

In recent years, a lot of attention in the hydrologic literature is given to model parameter uncertainty analysis. The robustness estimation of uncertainty depends on the efficiency of sampling method used to generate the best fit responses (outputs) and on ease of use. This paper aims to investigate: (1) how sampling strategies effect the uncertainty estimations of hydrological models, (2) how to use this information in machine learning predictors of models uncertainty. Sampling of parameters may employ various algorithms. We compared seven different algorithms namely, Monte Carlo (MC) simulation, generalized likelihood uncertainty estimation (GLUE), Markov chain Monte Carlo (MCMC), shuffled complex evolution metropolis algorithm (SCEMUA), differential evolution adaptive metropolis (DREAM), partical swarm optimization (PSO) and adaptive cluster covering (ACCO) [1]. These methods were applied to estimate uncertainty of streamflow simulation using conceptual model HBV and Semi-distributed hydrological model SWAT. Nzoia catchment in West Kenya is considered as the case study. The results are compared and analysed based on the shape of the posterior distribution of parameters, uncertainty results on model outputs. The MLUE method [2] uses results of Monte Carlo sampling (or any other sampling shceme) to build a machine learning (regression) model U able to predict uncertainty (quantiles of pdf) of a hydrological model H outputs. Inputs to these models are specially identified representative variables (past events precipitation and flows). The trained machine learning models are then employed to predict the model output uncertainty which is specific for the new input data. The problem here is that different sampling algorithms result in different data sets used to train such a model U, which leads to several models (and there is no clear evidence which model is the best since there is no basis for comparison). A solution could be to form a committee of all models U and to sue a dynamic averaging scheme to generate the final output. [1] N. Kayastha, D. L. Shrestha and D. P. Solomatine. Experiments with several methods of parameter uncertainty estimation in hydrological modeling. Proc. 9th Intern. Conf. on Hydroinformatics, Tianjin, China, September 2010. [2] D. L. Shrestha, N. Kayastha, and D. P. Solomatine. A novel approach to parameter uncertainty analysis of hydrological models using neural networks. Hydrol. Earth Syst. Sci., 13, 1235-1248, 2009.

Kayastha, Nagendra; Solomatine, Dimitri; Lal Shrestha, Durga; van Griensven, Ann

2013-04-01

53

Modeling of surface microtopography and its impacts on hydrologic processes  

NASA Astrophysics Data System (ADS)

Understanding the impacts of surface microtopography on hydrologic processes is critical. The objectives of this thesis research are: (1) to evaluate the effects of DEM resolution on microtopographic characteristics, hydrologic connectivity, and modeling of hydrologic processes; and (2) to assess the influences of multiple rainfall events on surface and subsurface hydrologic processes with the use of a puddle-to-puddle (P2P) modeling system. The change in DEM resolution has a significant effect on how surface microtopography is depicted, which in turn alters the hydrologic response of a topographic surface. The smoothing of reduced DEM resolution tends to enhance hydrologic connectivity, reduce the depression storage and infiltration, and increase surface runoff. Temporal rainfall distribution results in spatio-temporal variations in soil water dynamics, depression storage, infiltration, hydrologic connectivity, and surface runoff. The reduction in ponding time and infiltration, and the enhancement of hydrologic connectivity further caused earlier and greater surface runoff generation.

Habtezion, Noah Lebassi

54

Distributed Hydrologic Models for Flow Forecasts - Part 1  

NSDL National Science Digital Library

Distributed Hydrologic Models for Flow Forecasts – 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

55

Improvement in calibration strategy of a conceptual distributed hydrological model using spatial data analysis  

NASA Astrophysics Data System (ADS)

Using Hydrological Models is the most common way for forecasting, water management or design to provide information for decision making. The most difficult and, at the same time, challenging part is the identification of model parameters. The calibration based on temporal investigations has been under study by many researchers, but less important has been given for spatial similarities. The purpose of this study is to investigate how a critical HRU (Hydrological Response Unit) can be formulated using catchment characteristics. Data depth function was used to identify critical HRU. Mostly calibrating the parameters for big catchments is time-consuming and costly computation. To compensate these difficulties, we would focus on grids which have the biggest effect on the catchment area and which influence model parameters most. Using Tukey's half space depth function depth of all grid cells for N catchments properties were calculated. The grid cells which have lower depth are critical for identifying the model parameters. A comparison was made by calibrating a distributed conceptual HBV model using all the grid cells and also on only selected critical grid cells. It has been found that Model calibrated only on Selected critical grid cells have very similar performance as we could have calibrated on all grid cells. This has reduced the complexity in parameter estimation and decrease the time of computation. The Upper Neckar catchment located in south west of Germany was used in order to demonstrate its methodology.

Rabiei, Ehsan; Singh, Shailesh Kumar; Bárdossy, András.

2010-05-01

56

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

NASA Astrophysics Data System (ADS)

Drought 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

57

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

58

The skill of seasonal ensemble low-flow forecasts in the Moselle River for three 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 one data-driven model based on Artificial Neural Networks (ANNs) for the Moselle River. The three models, i.e. HBV, GR4J and ANN-Ensemble (ANN-E), all use forecasted meteorological inputs (precipitation P and potential evapotranspiration PET), whereby we employ ensemble seasonal meteorological forecasts. We compared low-flow forecasts for 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 models. 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 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 runoff during low-flow periods 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. The results of the comparison of forecast skills with varying lead times show that GR4J is less skilful than ANN-E and HBV. 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.

2015-01-01

59

Scientists unite to improve models coupling atmosphere and hydrology  

NASA Astrophysics Data System (ADS)

It was right down to business at a workshop organized by the Global Energy and Water-cycle Experiment Continental-scale International Project (GCIP) in Silver Spring, Md., from May 9 to 10, 1996. More than 40 atmospheric and hydrological scientists from government and academia met to review past progress and guide scientific priorities within NOAA's and NASA's research programs into coupled hydrologic-atmospheric modeling.Given GCIP's dual goals of improving weather and climate prediction for North America at timescales up to interannual, and of providing hydrological interpretation of these predictions, the workshop focused on research that addresses three questions: To what extent is meteorological prediction at daily to seasonal timescales sensitive to hydrologic-atmospheric coupling processes? To what extent can meteorological predictions be hydrologically interpreted? And how can models of relevant hydrologic-atmospheric coupling processes be improved to enhance meteorological and hydrological prediction?

Shuttleworth, W. James

60

Hydrological validation of multifractal rainfall simulation models  

NASA Astrophysics Data System (ADS)

The observed scaling invariance properties of rainfall time series have often been put forward to justify the choice of multifractal (scaling) models for rainfall stochastic modelling. These models are nevertheless seldom validated on real hydrological applications. Two types of multifractal models - the first one with a Log-Poisson generator and the second one with a uniform generator - were calibrated on a 8 year point rainfall series with a five minute time step. The results obtained with the rainfall series simulated with these models on two hydrological applications (the computation of intensity-duration-frequency, IDF, curves and the conception of a urban drainage storage volume) were compared with those obtained with the original measured rainfall series. The disagreements reveal some limitations of the multifractal models. On the one hand, using the vocabulary of the multifractalists, the models are calibrated on the basis of the statistical properties of the simulated undressed series while the IDF curves are computed on the dressed series. The statistical properties of both types of series clearly differ if a canonical model is used : here the model with the Log-Poisson generator. On the other hand, the optimal dimensions of the storage volume depend on the shape of the hyetographs. The discordances between the volumes obtained with the simulated or measured rainfall series indicate that the temporal structure of the simulated rainfall intensity series (i.e. the shapes of the simulated hyetographs) are not comparable with the one of the measured series. As a conclusion, multifractal models appear to reproduce accuratly only some of the properties of the real measured series. Their appropriateness should not be a priori asserted but verified for each considered application.

Mouhous, N.; Gaume, E.; Andrieu, H.

2003-04-01

61

Hydrologic Process Modules of the Regional Simulation Model: An Overview  

Microsoft Academic Search

The Regional Simulation Model is a regional finite-volume, aquifer-stream-surface hydrology model under development by the South Florida Water Management District. The Hydrologic Process Modules (HPM) are designed to solve the local surface water hydrology for RSM, where an HPM is assigned to each cell in the irregular mesh. The HPMs are solved explicitly at the beginning of each model time

Eric Flaig; Randy VanZee; Wasantha Lal

62

Plant growth simulation for landscape scale hydrologic modeling  

Technology Transfer Automated Retrieval System (TEKTRAN)

Landscape scale hydrologic models can be improved by incorporating realistic, process-oriented plant models for simulating crops, grasses, and woody species. The objective of this project was to present some approaches for plant modeling applicable to hydrologic models like SWAT that can affect the...

63

Validation of uncertainty estimates in hydrologic modelling  

NASA Astrophysics Data System (ADS)

Meaningful characterization of uncertainties affecting conceptual rainfall-runoff (CRR) models remains a challenging research area in the hydrological community. Numerous methods aimed at quantifying the uncertainty in hydrologic predictions have been proposed over the last decades. In most cases, the outcome of such methods takes the form of a predictive interval, computed from a predictive distribution. Regardless of the method used to derive it, it is important to notice that the predictive distribution results from the assumptions made during the inference. Consequently, unsupported assumptions may lead to inadequate predictive distributions, i.e. under- or over-estimated uncertainties. It follows that the estimated predictive distribution must be thoroughly scrutinized ("validated"); as discussed by Hall et al. [2007] "Without validation, calibration is worthless, and so is uncertainty estimation". The aim of this communication is to study diagnostic tools aimed at assessing the reliability of uncertainty estimates. From a methodological point of view, this requires diagnostic approaches that compare a time-varying distribution (the predictive distribution at all times t) to a time series of observations. This is a much more stringent test than validation methods currently used in hydrology, which simply compare two time series (observations and "optimal" simulations). Indeed, standard goodness-of-fit assessments (e.g. using the Nash-Sutcliff statistic) can not check if the predictive distribution is consistent with the observed data. The usefulness of the proposed diagnostic tools will be illustrated with a case study comparing the performance of several uncertainty quantification frameworks. In particular, it will be shown that standard validation approaches (e.g. based on the Nash-Sutcliff statistic or verifying that about p% of the observations lie within the p% predictive interval) are not able to discriminate competing frameworks whose performance (in terms of uncertainty quantification) is evidently different.

Thyer, M.; Engeland, K.; Renard, B.; Kuczera, G.; Franks, S.

2009-04-01

64

Plant adaptive behaviour in hydrological models (Invited)  

NASA Astrophysics Data System (ADS)

Models that will be able to cope with future precipitation and evaporation regimes need a solid base that describes the essence of the processes involved [1]. Micro-behaviour in the soil-vegetation-atmosphere system may have a large impact on patterns emerging at larger scales. A complicating factor in the micro-behaviour is the constant interaction between vegetation and geology in which water plays a key role. The resilience of the coupled vegetation-soil system critically depends on its sensitivity to environmental changes. As a result of environmental changes vegetation may wither and die, but such environmental changes may also trigger gene adaptation. Constant exposure to environmental stresses, biotic or abiotic, influences plant physiology, gene adaptations, and flexibility in gene adaptation [2-6]. Gene expression as a result of different environmental conditions may profoundly impact drought responses across the same plant species. Differences in response to an environmental stress, has consequences for the way species are currently being treated in models (single plant to global scale). In particular, model parameters that control root water uptake and plant transpiration are generally assumed to be a property of the plant functional type. Assigning plant functional types does not allow for local plant adaptation to be reflected in the model parameters, nor does it allow for correlations that might exist between root parameters and soil type. Models potentially provide a means to link root water uptake and transport to large scale processes (e.g. Rosnay and Polcher 1998, Feddes et al. 2001, Jung 2010), especially when powered with an integrated hydrological, ecological and physiological base. We explore the experimental evidence from natural vegetation to formulate possible alternative modeling concepts. [1] Seibert, J. 2000. Multi-criteria calibration of a conceptual runoff model using a genetic algorithm. Hydrology and Earth System Sciences 4(2): 215-224. [2] McClintock B. The significance of responses of the genome to challenge. Science 1984; 226: 792-801 [3] Ries G, Heller W, Puchta H, Sandermann H, Seldlitz HK, Hohn B. Elevated UV-B radiation reduces genome stability in plants. Nature 2000; 406: 98-101 [4] Lucht JM, Mauch-Mani B, Steiner H-Y, Metraux J-P, Ryals, J, Hohn B. Pathogen stress increases somatic recombination frequency in Arabidopsis. Nature Genet. 2002; 30: 311-314 [5] Kovalchuk I, Kovalchuk O, Kalck V., Boyko V, Filkowski J, Heinlein M, Hohn B. Pathogen-induced systemic plant signal triggers DNA rearrangements. Nature 2003; 423: 760-762 [6] Cullis C A. Mechanisms and control of rapid genomic changes in flax. Ann. Bot. (Lond.) 2005; 95: 201-206 [7] de Rosnay, P. and J. Polcher. 1998. Modelling root water uptake in a complex land surface scheme coupled to a GCM. Hydrology and Earth System Sciences 2: 239-255. [8] Feddes, R.A., H. Hoff, M. Bruen, T. Dawson, P. de Rosnay, P. Dirmeyer, R.B. Jackson, P. Kabat, A. Kleidon, A. Lilly, and A.J. Pitman. 2001. Modeling root water uptake in hydrological and climate models. Bulletin of the American Meteorological Society 82: 2797-2809. [9] Jung, M., M. Reichstein, P. Ciais, S.I. Seneviratne, J. Sheffield et al. 2010. Recent decline in the global land evaporation trend due to limited moisture supply. Nature 476: 951-954, doi:10.1038/nature09396.

van der Ploeg, M. J.; Teuling, R.

2013-12-01

65

Recursive parameter estimation of hydrologic models  

NASA Astrophysics Data System (ADS)

Proposed is a nonlinear filtering approach to recursive parameter estimation of conceptual watershed response models in state-space form. The conceptual model state is augmented by the vector of free parameters which are to be estimated from input-output data, and the extended Kaiman filter is used to recursively estimate and predict the augmented state. The augmented model noise covariance is parameterized as the sum of two components: one due to errors in the augmented model input and another due to errors in the specification of augmented model constants that were estimated from other than input-output data (e.g., topographic and rating curve constants). These components depend on the sensitivity of the augmented model to input and uncertain constants. Such a novel parameterization allows for nonstationary model noise statistics that are consistent with the dynamics of watershed response as they are described by the conceptual watershed response model. Prior information regarding uncertainty in input and uncertain constants in the form of degree-of-belief estimates of hydrologists can be used directly within the proposed formulation. Even though model structure errors are not explicitly parameterized in the present formulation, such errors can be identified through the examination of the one-step ahead predicted normalized residuals and the parameter traces during convergence. The formulation is exemplified by the estimation of the parameters of a conceptual hydrologic model with data from the 2.1-km2 watershed of Woods Lake located in the Adirondack Mountains of New York.

Rajaram, Harihar; Georgakakos, Konstantine P.

1989-02-01

66

Comparing TRMM 3B42, CFSR and ground-based rainfall estimates as input for hydrological models, in data scarce regions: the Upper Blue Nile Basin, Ethiopia  

NASA Astrophysics Data System (ADS)

Accurate prediction of hydrological models requires accurate spatial and temporal distribution of rainfall observation network. In developing countries rainfall observation station network are sparse and unevenly distributed. Satellite-based products have the potential to overcome these shortcomings. The objective of this study is to compare the advantages and the limitation of commonly used high-resolution satellite rainfall products as input to hydrological models as compared to sparsely populated network of rain gauges. For this comparison we use two semi-distributed hydrological models Hydrologiska Byråns Vattenbalansavdelning (HBV) and Parameter Efficient Distributed (PED) that performed well in Ethiopian highlands in two watersheds: the Gilgel Abay with relatively dense network and Main Beles with relatively scarce rain gauge stations. Both are located in the Upper Blue Nile Basin. The two models are calibrated with the observed discharge from 1994 to 2003 and validated from 2004 to 2006. Satellite rainfall estimates used includes Climate Forecast System Reanalysis (CFSR), Tropical Rainfall Measuring Mission (TRMM) 3B42 version 7 and ground rainfall measurements. The results indicated that both the gauged and the CFSR precipitation estimates were able to reproduce the stream flow well for both models and both watershed. TRMM 3B42 performed poorly with Nash Sutcliffe values less than 0.1. As expected the HBV model performed slightly better than the PED model, because HBV divides the watershed into sub-basins resulting in a greater number of calibration parameters. The simulated discharge for the Gilgel Abay was better than for the less well endowed (rain gauge wise) Main Beles. Finally surprisingly, the ground based gauge performed better for both watersheds (with the exception of extreme events) than TRMM and CFSR satellite rainfall estimates. Undoubtedly in the future, when improved satellite products will become available, this will change.

Worqlul, A. W.; Collick, A. S.; Tilahun, S. A.; Langan, S.; Rientjes, T. H. M.; Steenhuis, T. S.

2015-02-01

67

Operational use of distributed hydrological models. Experiences and challenges at a Norwegian hydropower company (Agder Energi).  

NASA Astrophysics Data System (ADS)

The Scandinavian hydropower industry has traditionally adopted the lumped conceptual hydrological model - HBV, as the tool for producing forecasts of inflows and mountain snow packs. Such forecasting systems - based on lumped conceptual models - have several drawbacks. Firstly, a lumped model does not produce spatial data, and comparisons with remote sensed snow cover data (which are now available) are complicated. Secondly, several climate parameters such as wind speed are now becoming more available and can potentially improve forecasts due to improved estimates of precipitation gauge efficiency, and more physically correct calculation of turbulent heat fluxes. At last, when the number of catchments increases, it is cumbersome and slow to run multiple hydrology models compared to running one model for all catchments. With the drawbacks of the lumped hydrology models in mind, and with inspiration from other forecasting systems using distributed models, Agder Energy decided to develop a forecasting system applying a physically based distributed model. In this paper we describe an operational inflow and snowpack forecast system developed for the Scandinavian mountain range. The system applies a modern macroscale land surface hydrology model (VIC) which in combination with historical climate data and weather predictions can be used to produce both short-term, and seasonal forecasts of inflow and mountain snowpack. Experiences with the forecast system are illustrated using results from individual subcatchments as well as aggregated regional forecasts of inflow and snowpack. Conversion of water volumes into effective energy inflow are also presented and compared to data from the Nordic hydropower system. Further on, we document several important "lessons-learned" that may be of interest to the hydrological research community. Specifically a semi-automatic data cleansing system combining spatial and temporal visualization techniques with statistical procedures are combined into a robust and fast data cleansing and interpolation system. One experience from this work is that advanced interpolation techniques (kriging), do not outperform calibrated inverse distance methods when also computational speed is used as a criteria for model selection. The paper also discusses several challenges related to uncertainty in simulated snow reservoir, regionalization of parameters, choice of spatial resolution, techniques for reducing computational needs without compromising information needs, amongst others.

Viggo Matheussen, Bernt; Andresen, Arne; Weisser, Claudia

2014-05-01

68

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

69

Adenoviral-vector mediated transfer of HBV-targeted ribonuclease can inhibit HBV replication in vivo  

Microsoft Academic Search

Hepatitis B virus (HBV)-targeted ribonuclease (HBV-TR) is a fused protein of HBV core protein and a ribonuclease, human eosinophil-derived neurotoxin (hEDN). Our previous results showed that HBV-TR could effectively inhibit HBV replication in vitro. To test whether HBV-TR can inhibit HBV replication in vivo, we constructed a recombinant adenoviral vector expressing HBV-TR (Ad-TR) and used it to treat HBV-transgenic mice.

Ya Zhao; Yinghui Li; Jun Liu; Zhongxiang Liu; Yuxiao Huang; Junchuan Lei; Shumei Li; Caifang Xue

2008-01-01

70

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...

71

Multi-Objective Calibrationo of Hydrologic Model Using Satellite Data  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hydrologic modeling often involves a large number of parameters, some of which cannot be measured directly and may vary with land cover, soil or even seasons. Therefore parameter estimation is a critical step in applying a hydrologic model to any study area. Parameter estimation is typically done by...

72

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

73

Climate Change: Coupling Hydrologic Modeling with Policy Making  

E-print Network

1 Climate Change: Coupling Hydrologic Modeling with Policy Making Aleix Serrat-Capdevila1 Program #12;2 Climate Change: Coupling Hydrologic Modeling with Policy Making Summary The US Southwest publications seem to focus on the long term evolution of a basin's water balance due to climate change impacts

Fay, Noah

74

Flood modelling in complex hydrologic systems with sparsely resolved data  

Microsoft Academic Search

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

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

2009-01-01

75

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

76

Coupling meteorological and hydrological models for flood forecasting Hydrology and Earth System Sciences, 9(4), 333346 (2005) EGU  

E-print Network

Coupling meteorological and hydrological models for flood forecasting 333 Hydrology and Earth System Sciences, 9(4), 333346 (2005) © EGU Coupling meteorological and hydrological models for flood.bartholmes@jrc.it Abstract This paper deals with the problem of analysing the coupling of meteorological meso

Paris-Sud XI, Université de

77

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

78

Hydrology  

USGS Publications Warehouse

Hydrologic process are the main determinants of the type of wetland located on a site. Precipitation, groundwater, or flooding interact with soil properties and geomorphic setting to yield a complex matrix of conditions that control groundwater flux, water storage and discharge, water chemistry, biotic productivity, biodiversity, and biogeochemical cycling. Hydroperiod affects many abiotic factors that in turn determine plant and animal species composition, biodiversity, primary and secondary productivity, accumulation, of organic matter, and nutrient cycling. Because the hydrologic regime has a major influence on wetland functioning, understanding how hydrologic changes influence ecosystem processes is essential, especially in light of the pressures placed on remaining wetlands by society's demands for water resources and by potential global changes in climate.

Eisenbies, Mark H.; Hughes, W. Brian

2000-01-01

79

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

80

FIELD AND POND HYDROLOGIC ANALYSES WITH THE SPAW MODEL  

Technology Transfer Automated Retrieval System (TEKTRAN)

The SPAW (Soil-Plant-Air-Water) computer model simulates the daily hydrology of agricultural fields and ponds including wetlands, lagoons and reservoirs. Field hydrology is represented by daily climatic descriptions of rainfall, temperature and evaporation; a layered soil profile with automated wat...

81

Water storage concepts in hydrological catchment models  

NASA Astrophysics Data System (ADS)

In most hydrological catchment model some form of water storage is simulated, but the concepts of storage differ largely. While the simplest concepts might be appropriate when the main focus is runoff quantity, more complex concepts might be needed when also other variables are of interest. Besides its importance for the precipitation-runoff dynamics, water storage is also important because of its relation to catchment mean transit times. The water storage concepts range from simple lumped, box-type approaches to fully-distributed representations of soil water storage. The concepts differ also in which water stores are included; while conceptual runoff models often only consider the dynamic storage, more physically-based descriptions consider the entire water storage including, for instance, immobile water stores. Depending on model structure, the possible interactions between different water stores are represented in varying complexity. Yet another concept of water storage is used when water storage is estimated through tracer hydrological time series analysis. In this contribution the different concepts of water storage are compared both in principle and with concrete examples. One important aspect of water storage concepts is also the distinction between saturated and unsaturated water storage. A simple approach to quantify total storage amounts in the saturated and unsaturated zone, including the dynamic variations of these two stores, is demonstrated for a small Swedish catchment and compared to other approaches of storage estimations. In another study, it was found that catchment storage estimates based on a tracer respective modeling approach were highly correlated for a number of Scottish catchments, but differed in orders of magnitude. This example is used to discuss the effect of using different concepts when estimating water storage. It is generally important to be careful when interpreting water storage estimates, as they might largely depend on the concept used for quantification. The simplest approaches often only consider a fraction of the total water storage and do therefore not represent the real processes. More complex storage concepts, on the other hand, imply the need for more parameters and, thus, increased parameter uncertainty.

Seibert, J.

2011-12-01

82

Data Mining of Hydrological Model Performances  

NASA Astrophysics Data System (ADS)

Multi-objective criteria have long been used to infer hydrological simulations and fit the natural world. On the other hand, modelling frameworks are also becoming more and more popular as identification of the processes occurring in a catchment is still a very uncertain matter. In theory, multi-objective criteria and multi-model frameworks should be used in combination so that the 'representation' of the catchment is fitted to the observations, not only the simulated results. In practise those approaches are highly computationally demanding. The modeller is often obliged to find a compromise reducing either the number of objective functions or model structures taken into consideration. This compromise is becoming obsolete using parallel computing. In the present study we investigate the extend to which model selection algorithms and regionalisation techniques can be improved by such facilities and highlight the challenges that still need to be addressed. The model simulations are obtained using an ensemble of conceptual lumped models (FUSE by Clark et al. 2008), but techniques and suggestions are of general use and applicable to any modelling frameworks. In particular we developed a novel model selection algorithm tuned to drastically reduce the subjectivity in the analysis. The procedure was automated and coupled with redundancy reduction techniques such as PCA and Cluster Analysis. Results show that the actual model 'representation' has the shape of a set of complementing model structures. It is also possible to capture intra-annum dynamics of the response as the algorithm recognises subtle variations in the selected model structures in different seasons. Similar variations can be found analysing different catchments. This suggests the same methodology would be suitable for analysing spatial patterns in the distribution of suitable model structures and maybe long term dynamics in relation with expedited climate modifications. Although the mentioned methodology has proven to be successful with regards to the case study, some limitations are worth noting. If this is going to be applied to the more general case of 'models of everywhere', for instance, there could be dominant processes not described in the FUSE framework. Further studies could therefore extend the current framework to include routines able to simulate missing processes.

Vitolo, Claudia; Buytaert, Wouter

2013-04-01

83

Assessing the response of subgrid hydrologic processes to atmospheric forcing with a hydrologic model system  

NASA Astrophysics Data System (ADS)

An integrated hydrologic model system (HMS) was developed and used to study hydrologic processes and systems responding to various climatic forcings. The modeling system operates with a time step of minutes to days to facilitate coupling with a mesoscale meteorological model (MM). The major emphasis with HMS is on the interaction among climate, land surface, surface water, and ground water. HMS utilizes spatially detailed information on climate, soil type, land use, digital elevation, and hydrologic parameters. The focus of this study was to improve the presentation of rainfall-runoff partitioning by implementing subgrid-scale spatial variability in precipitation and hydraulic conductivity. The practical application of HMS is demonstrated in the hydrologic simulation of a major sub-basin of the Susquehanna River Basin in Pennsylvania. Questions concerning data preparation, model calibration, and subgrid-scale spatial variability are addressed in the hydrologic simulation. The simulation without considering subgrid-scale spatial variability using both observed and MM5-simulated precipitations significantly underestimates the streamflow. The simulated and observed streamflows compare well in the simulation with consideration of the subgrid-scale spatial variability in hydraulic conductivity using observed precipitation. With the implementation of subgrid-scale spatial variability in precipitation and hydraulic conductivity, the simulated results using MM5-simulated precipitation were improved in terms of fit between the simulated and observed streamflows.

Yu, Z.

2000-07-01

84

The TopoFlow Hydrologic Model: A New Community Project  

Microsoft Academic Search

TopoFlow is a powerful, spatially-distributed hydrologic model with a user-friendly, wizard-style point-and-click interface. It is an open-source model that was designed to be easily modified and extended by a user community of hydrologists. Its main purpose is to model many different physical processes in a watershed with the goal of accurately predicting how various hydrologic variables will evolve in time

S. D. Peckham

2004-01-01

85

Progress Towards Community Modeling in Hydrologic Science (Invited)  

NASA Astrophysics Data System (ADS)

In this presentation we review CUAHSI-led activities to advance community modeling in hydrologic science. In particular, these include the Community Hydrologic Modeling Platform (CHyMP) and the HydroHUB. The goal of CHyMP is to significantly advance the development, availability and support of hydrologic models in order to enable transformative science. We make the case that an accelerated, community-wide effort is required in order to address a host of high-priority issues related to hydrology and global change, including food, energy and water security. HydroHUB is website that will improve access to models broadly related to water, including models developed under the CHyMP activity. The status of these activities and results from recent workshops will be discussed, as will near- and long-term plans for the advancing CHyMP and HydroHUB.

Famiglietti, J. S.; Murdoch, L. C.; Lakshmi, V.; Hooper, R. P.

2009-12-01

86

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

87

Hydrologic impact of climate change in the Saguenay watershed: comparison of downscaling methods and hydrologic models  

NASA Astrophysics Data System (ADS)

Changes in global climate will have significant impact on local and regional hydrological regimes, which will in turn affect ecological, social and economical systems. However, climate-change impact studies on hydrologic regime have been relatively rare until recently, mainly because Global Circulation Models, which are widely used to simulate future climate scenarios, do not provide hourly or daily rainfall reliable enough for hydrological modeling. Nevertheless, more reliable rainfall series corresponding to future climate scenarios can be derived from GCM outputs using the so called 'downscaling techniques'. This study applies two types of statistical (a stochastic and a regression based) downscaling techniques to generate the possible future values of local meteorological variables such as precipitation and temperature in the Chute-du-Diable sub-basin of the Saguenay watershed in northern Québec, Canada. The downscaled data is used as input to two different hydrologic models to simulate the corresponding future flow regime in the catchment. In addition to assessing the relative potential of the downscaling methods, the paper also provides comparative study results of the possible impact of climate change on river flow and total reservoir inflow in the Chute-du-Diable basin. Although the two downscaling techniques do not provide identical results, the time series generated by both methods indicates a general increasing trend in the mean daily temperature values. While the regression based downscaling technique resulted in an increasing trend in the mean and variability of daily precipitation values, such a trend is not obvious in the case of precipitation time series downscaled with the stochastic weather generator. Moreover, the hydrologic impact analysis made with the downscaled precipitation and temperature time series as input to the two hydrological models suggest an overall increasing trend in mean annual river flow and reservoir inflow as well as earlier spring peak flows in the basin.

Dibike, Yonas B.; Coulibaly, Paulin

2005-06-01

88

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

89

ENHANCING HYDROLOGICAL SIMULATION PROGRAM - FORTRAN MODEL CHANNEL HYDRAULIC REPRESENTATION  

EPA Science Inventory

The Hydrological Simulation Program? FORTRAN (HSPF) is a comprehensive watershed model that employs depth-area - volume - flow relationships known as the hydraulic function table (FTABLE) to represent the hydraulic characteristics of stream channel cross-sections and reservoirs. ...

90

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

91

Modelling the hydrology of the Greenland ice sheet   

E-print Network

This thesis aims to better understand the relationships between basal water pressure, friction, and sliding mechanisms at ice sheet scales. In particular, it develops a new subglacial hydrology model (Hydro) to explicitly ...

Karatay, Mehmet Rahmi

2011-06-28

92

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

93

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

94

Toward improved calibration of hydrologic models: Multiple and noncommensurable measures of information  

Microsoft Academic Search

Several contributions to the hydrological literature have brought into question the continued usefulness of the classical paradigm for hydrologic model calibration. With the growing popularity of sophisticated \\

Hoshin Vijai Gupta; Soroosh Sorooshian; Patrice Ogou Yapo

1998-01-01

95

Ensemble stream flow predictions, a way towards better hydrological forecasting  

NASA Astrophysics Data System (ADS)

The hydrological forecasting division at SMHI has been using hydrological EPS and hydrological probabilities forecasts operationally since some years ago. The inputs to the hydrological model HBV are the EPS forecasts from ECMWF. From the ensemble, non-exceedance probabilities are estimated and final correction of the ensemble spread, based on evaluation is done. Ensemble stream flow predictions are done for about 80 indicator basins in Sweden, where there is a real-time discharge gauge. The EPS runs are updated daily against the latest observed discharge. Flood probability maps for exceeding a certain threshold, i.e. a certain warning level, are produced automatically once a day. The flood probabilistic forecasts are based on a HBV- model application, (called HBV-Sv, HBV Sweden) that covers the whole country and consist of 1001 subbasins with an average size between 200 and 700 km2. Probabilities computations for exceeding a certain warning level are made for each one of these 1001 subbasins. Statistical flood levels have been calculated for each river sub-basin. Hydrological probability forecasts should be seen as an early warning product that can give better support in decision making to end-users communities, for instance Civil Protections Offices and County Administrative Boards, within flood risk management. The main limitations with probability forecasts are: on one hand, difficulties to catch small-scale rain (mainly due to resolution of meteorological models); on the other hand, the hydrological model can't be updated against observations in all subbasins. The benefits of working with probabilities consist, first of all, of a new approach when working with flood risk management and scenarios. A probability forecast can give an early indication for Civil Protection that "something is going to happen" and to gain time in preparing aid operations. The ensemble stream flow prediction at SMHI is integrated with the national forecasting system and the products are available to specialized end-users via Internet.

Edlund, C.

2009-04-01

96

Rapid Post Fire Hydrologic Watershed Assessment using the AGWA GIS -based Hydrologic Modeling Tool  

Microsoft Academic Search

Rapid post -fire watershed assessment to identify potential trouble spots for erosion and flooding can potentially aid land managers and Bu rned Area Emergency Rehabilitation (BAER) teams in deploying mitigation and rehabilitation resources. These decisions are inherently complex and spatial in nature and require a distributed hydrological modeling approach. The extensive data requirements an d the task of building input

D. C. Goodrich; H. Evan Canfield; I. Shea Burns; D. J. Semmens; S. N. Miller; M. Hernandez; L. R. Levick; D. P. Guertin; W. G. Kepner

97

Limited Effects of Fasting on Hepatitis B Virus (HBV) Biosynthesis in HBV Transgenic Mice?  

PubMed Central

Nuclear receptors have a unique role in governing hepatitis B virus (HBV) transcription and replication. Hepatocyte nuclear factor 4? (HNF4?) and retinoid X receptor ? (RXR?) plus peroxisome proliferator-activated receptor ? (PPAR?) have been shown to support viral biosynthesis in nonhepatoma cells in the absence of additional liver-enriched transcription factors. However, the in vivo importance of these nuclear receptors in HBV biosynthesis has been investigated only to a limited extent. Fasting has been shown to activate gluconeogenesis, in part, by activating PPAR? coactivator 1 ?, which in turn leads to activation of HNF4?- and RXR?/PPAR?-mediated transcription. As HBV pregenomic RNA synthesis is primarily believed to be regulated by HNF4? under normal physiological conditions, it was of interest to determine the effect of fasting on the levels of HBV RNA and DNA synthesis. Fasting was shown to rather modestly increase the levels of viral proteins, transcripts, and replication intermediates in the HBV transgenic mouse model of chronic viral infection, suggesting that caloric restriction may modulate viremia to some extent during natural infection. PMID:19073739

Li, Lie; Oropeza, Claudia E.; Kaestner, Klaus H.; McLachlan, Alan

2009-01-01

98

Limited effects of fasting on hepatitis B virus (HBV) biosynthesis in HBV transgenic mice.  

PubMed

Nuclear receptors have a unique role in governing hepatitis B virus (HBV) transcription and replication. Hepatocyte nuclear factor 4alpha (HNF4alpha) and retinoid X receptor alpha (RXRalpha) plus peroxisome proliferator-activated receptor alpha (PPARalpha) have been shown to support viral biosynthesis in nonhepatoma cells in the absence of additional liver-enriched transcription factors. However, the in vivo importance of these nuclear receptors in HBV biosynthesis has been investigated only to a limited extent. Fasting has been shown to activate gluconeogenesis, in part, by activating PPARgamma coactivator 1 alpha, which in turn leads to activation of HNF4alpha- and RXRalpha/PPARalpha-mediated transcription. As HBV pregenomic RNA synthesis is primarily believed to be regulated by HNF4alpha under normal physiological conditions, it was of interest to determine the effect of fasting on the levels of HBV RNA and DNA synthesis. Fasting was shown to rather modestly increase the levels of viral proteins, transcripts, and replication intermediates in the HBV transgenic mouse model of chronic viral infection, suggesting that caloric restriction may modulate viremia to some extent during natural infection. PMID:19073739

Li, Lie; Oropeza, Claudia E; Kaestner, Klaus H; McLachlan, Alan

2009-02-01

99

Assessing hydrologic response to climate change of a stream watershed using SLURP hydrological model  

Microsoft Academic Search

The impact on streamflow and groundwater recharge considering future potential climate and land use changes was assessed using\\u000a Semi-distributed Land-Use Runoff Process (SLURP) continuous hydrologic model. The model was calibrated and verified using\\u000a 4 years (1999–2002) daily observed streamflow data for a 260.4 km2 watershed which has been continuously urbanized during the past couple of decades. The model was calibrated

So Ra Ahn; Geun Ae Park; In Kyun Jung; Kyoung Jae Lim; Seong Joon Kim

2011-01-01

100

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

101

A flexible modeling package for topographically based watershed hydrology  

Microsoft Academic Search

An OBJect-oriented TOPographic-based (OBJTOP) hydrological model with a graphical user interface (GUI) was created using object-oriented design (OOD) methods and the objected-oriented programming (OOP) language-C++. OBJTOP presents an array of alternative TOPMODEL hydrological processes of (1) saturation excess or the mixture of infiltration\\/saturation excess overland flow, (2) exponential or power law decay of hydraulic conductivity with soil depth, (3) topographic

Jun Wang; Theodore A. Endreny; James M. Hassett

2005-01-01

102

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

103

Strategies for using remotely sensed data in hydrologic models  

NASA Technical Reports Server (NTRS)

Present and planned remote sensing capabilities were evaluated. The usefulness of six remote sensing capabilities (soil moisture, land cover, impervious area, areal extent of snow cover, areal extent of frozen ground, and water equivalent of the snow cover) with seven hydrologic models (API, CREAMS, NWSRFS, STORM, STANFORD, SSARR, and NWSRFS Snowmelt) were reviewed. The results indicate remote sensing information has only limited value for use with the hydrologic models in their present form. With minor modifications to the models the usefulness would be enhanced. Specific recommendations are made for incorporating snow covered area measurements in the NWSRFS Snowmelt model. Recommendations are also made for incorporating soil moisture measurements in NWSRFS. Suggestions are made for incorporating snow covered area, soil moisture, and others in STORM and SSARR. General characteristics of a hydrologic model needed to make maximum use of remotely sensed data are discussed. Suggested goals for improvements in remote sensing for use in models are also established.

Peck, E. L.; Keefer, T. N.; Johnson, E. R. (principal investigators)

1981-01-01

104

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

105

Groundwater level simulations using a mesoscale hydrological model SWIM  

NASA Astrophysics Data System (ADS)

Integrated water resources management based on the profound understanding of the hydrological cycle may be a suitable tool for alleviating the upcoming water resource crisis. The application of the physically based distributed hydrological models is a significant tool for studies of hydrological behavior of river basins under the change of natural condition and. The SWIM (Soil and Water Integrated Model) is physically based hydrological models that could be used for impact studies. It is a continuous-time model which works on a daily step and integrates hydrology, vegetation, erosion and nutrients (N-nitrogen and P-phosphorus) at the river basin scale. Its hydrological module is based on the water balance equation, taking into account precipitation, evapotranspiration, percolation, surface runoff and subsurface runoff for the soil column subdivided into several layers. The catchment is spatially subdivided into hydrotops (or hydrologically similar response units) by GIS. The aim of this study was to examine the ability of this type of the model to simulate the course of the groundwater level in the mesoscale catchment in the Czech Republic. The weekly values of the groundwater table height were compared to the simulated ones at several uniformly distributed locations. In one particular site, the results were also discussed in the context of the soil moisture content. It was found that in the warm period of the year the model is able to simulate satisfactorily both the course of groundwater and soil moisture. Nevertheless, in the winter season the rate of percolation is probably underestimated as the simulated groundwater height is lower than observed and at the same time the soil moisture content is overestimated. Acknowledgement: The study was supported by the research grant GA AS CR IAA 300600901

Sipek, Vaclav

2013-04-01

106

A strategy for diagnosing and interpreting hydrological model nonstationarity  

NASA Astrophysics Data System (ADS)

This paper presents a strategy for diagnosing and interpreting hydrological nonstationarity, aiming to improve hydrological models and their predictive ability under changing hydroclimatic conditions. The strategy consists of four elements: (i) detecting potential systematic errors in the calibration data; (ii) hypothesizing a set of "nonstationary" parameterizations of existing hydrological model structures, where one or more parameters vary in time as functions of selected covariates; (iii) trialing alternative stationary model structures to assess whether parameter nonstationarity can be reduced by modifying the model structure; and (iv) selecting one or more models for prediction. The Scott Creek catchment in South Australia and the lumped hydrological model GR4J are used to illustrate the strategy. Streamflow predictions improve significantly when the GR4J parameter describing the maximum capacity of the production store is allowed to vary in time as a combined function of: (i) an annual sinusoid; (ii) the previous 365 day rainfall and potential evapotranspiration; and (iii) a linear trend. This improvement provides strong evidence of model nonstationarity. Based on a range of hydrologically oriented diagnostics such as flow-duration curves, the GR4J model structure was modified by introducing an additional calibration parameter that controls recession behavior and by making actual evapotranspiration dependent only on catchment storage. Model comparison using an information-theoretic measure (the Akaike Information Criterion) and several hydrologically oriented diagnostics shows that the GR4J modifications clearly improve predictive performance in Scott Creek catchment. Based on a comparison of 22 versions of GR4J with different representations of nonstationarity and other modifications, the model selection approach applied in the exploratory period (used for parameter estimation) correctly identifies models that perform well in a much drier independent confirmatory period.

Westra, Seth; Thyer, Mark; Leonard, Michael; Kavetski, Dmitri; Lambert, Martin

2014-06-01

107

Diagnostic calibration of a hydrological model in an alpine area  

NASA Astrophysics Data System (ADS)

Hydrological modeling depends on single- or multiple-objective strategies for parameter calibration using long time sequences of observed streamflow. Here, we demonstrate a diagnostic approach to the calibration of a hydrological model of an alpine area in which we partition the hydrograph based on the dominant runoff generation mechanism (groundwater baseflow, glacier melt, snowmelt, and direct runoff). The partitioning reflects the spatiotemporal variability in snowpack, glaciers, and temperature. Model parameters are grouped by runoff generation mechanism, and each group is calibrated separately via a stepwise approach. This strategy helps to reduce the problem of equifinality and, hence, model uncertainty. We demonstrate the method for the Tailan River basin (1324 km2) in the Tianshan Mountains of China with the help of a semi-distributed hydrological model (THREW).

He, Z.; Tian, F.; Hu, H. C.; Gupta, H. V.; Hu, H. P.

2014-01-01

108

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

109

Modeller subjectivity and calibration impacts on hydrological model applications: an event-based comparison for a road-adjacent catchment in south-east Norway.  

PubMed

Identifying a 'best' performing hydrologic model in a practical sense is difficult due to the potential influences of modeller subjectivity on, for example, calibration procedure and parameter selection. This is especially true for model applications at the event scale where the prevailing catchment conditions can have a strong impact on apparent model performance and suitability. In this study, two lumped models (CoupModel and HBV) and two physically-based distributed models (LISEM and MIKE SHE) were applied to a small catchment upstream of a road in south-eastern Norway. All models were calibrated to a single event representing typical winter conditions in the region and then applied to various other winter events to investigate the potential impact of calibration period and methodology on model performance. Peak flow and event-based hydrographs were simulated differently by all models leading to differences in apparent model performance under this application. In this case-study, the lumped models appeared to be better suited for hydrological events that differed from the calibration event (i.e., events when runoff was generated from rain on non-frozen soils rather than from rain and snowmelt on frozen soil) while the more physical-based approaches appeared better suited during snowmelt and frozen soil conditions more consistent with the event-specific calibration. This was due to the combination of variations in subsurface conditions over the eight events considered, the subsequent ability of the models to represent the impact of the conditions (particularly when subsurface conditions varied greatly from the calibration event), and the different approaches adopted to calibrate the models. These results indicate that hydrologic models may not only need to be selected on a case-by-case basis but also have their performance evaluated on an application-by-application basis since how a model is applied can be equally important as inherent model structure. PMID:25262294

Kalantari, Zahra; Lyon, Steve W; Jansson, Per-Erik; Stolte, Jannes; French, Helen K; Folkeson, Lennart; Sassner, Mona

2015-01-01

110

WEB-DHM: A distributed biosphere hydrological model developed by coupling a simple biosphere scheme with a hillslope hydrological model  

Technology Transfer Automated Retrieval System (TEKTRAN)

The coupling of land surface models and hydrological models potentially improves the land surface representation, benefiting both the streamflow prediction capabilities as well as providing improved estimates of water and energy fluxes into the atmosphere. In this study, the simple biosphere model 2...

111

Modeling Hydrology-Habitat-Fish Population Linkages for Lake Erie  

Microsoft Academic Search

Most large scale ecological models focus on population dynamics or nutrient and energy flows without explicitly considering habitat limitations. For example, in Lake Erie, tributary and near-shore habitat limit recruitment; yet these effects are not represented in existing models. Habitats will change with alterations of hydrology (e.g., due to climate change) or land use; moreover, such alterations can be deliberate

RICHARD M. ANDERSON; BENJAMIN F. HOBBS; JOSEPH F. KOONCE; ANA B. LOCCI

112

Step wise calibration of hydrological model using unusual events  

NASA Astrophysics Data System (ADS)

The length of the observation period used for hydrological model calibration has a great influence on the identification of the parameters, because the main information lies at a certain time period of the data series. Hydrologically unusual events play a great role to identify the parameters of the model. These unusual time periods can be identified from anticipated precipitation index (API) time series using statistical concept of Tukey’s Halfspace depth function. The result of this study shows that model calibrated on hydrologically unusual events can indentify the model parameters reasonably in gauged catchments. This same concept can be extended in ungauged catchments provided we start measuring unusual events. Possibility of days becoming unusual can be defined by the help of predicted precipitation. With the help of the data depth we can decide whether the predicted precipitation will lead to critical events or not. If it is a critical event we can measure the discharge and if it is not a critical then it is not important for the identification of the model parameters. This way from data scarce regions we can measure hydrological critical events and the model can be calibrated on these events. The methodology has been demonstrated using the HYMOD model on Upper Neckar catchment of Germany. The results of the study show that smartly selected and measured events are sufficient to identify the parameters of the model. Indeed, the prediction is as good as that arising from the calibration using the whole time period.

Singh, S.; Bárdossy, A.

2009-12-01

113

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

114

Performance measures and criteria for hydrologic and water quality models  

Technology Transfer Automated Retrieval System (TEKTRAN)

Performance measures and criteria are essential for model calibration and validation. This presentation will include a summary of one of the papers that will be included in the 2014 Hydrologic and Water Quality Model Calibration & Validation Guidelines Special Collection of the ASABE Transactions. T...

115

Hydrologic Modeling A SIMULATION OF THE HURRICANE CHARLEY STORM  

E-print Network

approach scenarios the potential for hurricane storm surge in the Charlotte Harbor may be catastrophic. KeyHydrologic Modeling A SIMULATION OF THE HURRICANE CHARLEY STORM SURGE AND ITS BREACH OF NORTH storm surge in the Charlotte Harbor vicinity. The model-simulated surge is in sufficiently good

Chen, Changsheng

116

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

117

Ensemble catchment hydrological modelling for climate change impact analysis  

NASA Astrophysics Data System (ADS)

It is vital to investigate how the hydrological model structure affects the climate change impact given that future changes not in the range for which the models were calibrated or validated are likely. Thus an ensemble modelling approach which involves a diversity of models with different structures such as spatial resolutions and process descriptions is crucial. The ensemble modelling approach was applied to a set of models: from the lumped conceptual models NAM, PDM and VHM, an intermediate detailed and distributed model WetSpa, to the highly detailed and fully distributed model MIKE-SHE. Explicit focus was given to the high and low flow extremes. All models were calibrated for sub flows and quick flows derived from rainfall and potential evapotranspiration (ETo) time series. In general, all models were able to produce reliable estimates of the flow regimes under the current climate for extreme peak and low flows. An intercomparison of the low and high flow changes under changed climatic conditions was made using climate scenarios tailored for extremes. Tailoring was important for two reasons. First, since the use of many scenarios was not feasible it was necessary to construct few scenarios that would reasonably represent the range of extreme impacts. Second, scenarios would be more informative as changes in high and low flows would be easily traced to changes of ETo and rainfall; the tailored scenarios are constructed using seasonal changes that are defined using different levels of magnitude (high, mean and low) for rainfall and ETo. After simulation of these climate scenarios in the five hydrological models, close agreement was found among the models. The different models predicted similar range of peak flow changes. For the low flows, however, the differences in the projected impact range by different hydrological models was larger, particularly for the drier scenarios. This suggests that the hydrological model structure is critical in low flow predictions, more than in high flow conditions. Hence, the mechanism of the slow flow component simulation requires further attention. It is concluded that a multi-model ensemble approach where different plausible model structures are applied, is extremely useful. It improves the reliability of climate change impact results and allows decision making to be based on uncertainty assessment that includes model structure related uncertainties. References: Ntegeka, V., Baguis, P., Roulin, E., Willems, P., 2014. Developing tailored climate change scenarios for hydrological impact assessments. Journal of Hydrology, 508C, 307-321 Vansteenkiste, Th., Tavakoli, M., Ntegeka, V., Willems, P., De Smedt, F., Batelaan, O., 2013. Climate change impact on river flows and catchment hydrology: a comparison of two spatially distributed models. Hydrological Processes, 27(25), 3649-3662. Vansteenkiste, Th., Tavakoli, M., Ntegeka, V., Van Steenbergen, N., De Smedt, F., Batelaan, O., Pereira, F., Willems, P., 2014. Intercomparison of five lumped and distributed models for catchment runoff and extreme flow simulation. Journal of Hydrology, in press. Vansteenkiste, Th., Tavakoli, M., Ntegeka, V., De Smedt, F., Batelaan, O., Pereira, F., Willems, P., 2014. Intercomparison of climate scenario impact predictions by a lumped and distributed model ensemble. Journal of Hydrology, in revision.

Vansteenkiste, Thomas; Ntegeka, Victor; Willems, Patrick

2014-05-01

118

Data assimilation of GRACE terrestrial water storage estimates into a regional hydrological model of the Rhine River basin  

NASA Astrophysics Data System (ADS)

Terrestrial water storage (TWS) can be defined as an integrated measure of surface water, soil moisture, snow water, and groundwater. TWS data is valuable for water resources management and hydrology. The ability to simulate realistic TWS is essential for understanding past hydrological events and predicting future changes of the hydrological cycle. Inadequacies in physics, deficiencies in land characteristics and uncertainties in meteorological data commonly limit the performance of hydrological models in estimating TWS. In this study, we investigated the benefits of assimilating TWS derived from the Gravity Recovery And Climate Experiment (GRACE) into the Wflow HBV-96 model using the Ensemble Kalman Filter (EnKF). Since hydrological model parameters are often uncertain over a large part of the Earth, we investigated the impact of GRACE assimilation in different model scenarios representing different degrees of data availability. Four case studies were considered comparing calibrated and non-calibrated model parameters and local and global forcing data. The chosen study area is the Rhine River basin. Our results were validated using in-situ stream gauge data. In all scenarios, the temporal signatures of the averaged TWS are similar after assimilating GRACE while the spatial distribution is heavily influenced by the model parameters and input data as well as their uncertainties. Assimilation using the EnKF reduced the standard deviation at every updating stage, resulting in lower standard deviations than the model or the observations alone. Discrepancies between the local and global precipitation products had a significant impact on discharge estimates. For instance, when the global forcing data were used, discharge was drastically overestimated when spurious heavy rainfall occurred during the winter. Based on the correlation coefficient, Nash-Sutcliffe coefficient (NS), and root-mean-square error (RMSE) computed between the estimated and measured discharges at 13 gauge stations, we concluded that GRACE assimilation slightly improves the model performance when the model is well calibrated (calibrated parameters with local forcing data). More importantly, the improvement observed for the non-calibrated model (non-calibrated parameters with global forcing data), suggests that the impact of GRACE assimilation may be more significant in data-sparse regions.

Tangdamrongsub, Natthachet; Steele-Dunne, Susan; Gunter, Brian C.; Widiastuti, Endang; Weerts, Albrecht; Ditmar, Pavel; Tsompanopoulos, Efstratios

2014-05-01

119

A Catchment-Based Hydrologic and Routing Modeling System with explicit river channels  

Microsoft Academic Search

In this paper, we present a macroscale hydrologic modeling system with an explicit representation of storage and movement of water in river channels and floodplains. The overall modeling system, called the Catchment-Based Hydrologic and Routing Modeling System (CHARMS), is composed of a land surface model and a river routing model that operate on a network of hydrologic catchments (or watersheds).

Gopi Goteti; James S. Famiglietti; Kwabena Asante

2008-01-01

120

Integrating Geophysics, Geology, and Hydrology for Enhanced Hydrogeological Modeling  

NASA Astrophysics Data System (ADS)

Geophysical measurements are important for providing information on the geological structure to hydrological models. Regional scale surveys, where several watersheds are mapped at the same time using helicopter borne transient electromagnetic, results in a geophysical model with a very high lateral and vertical resolution of the geological layers. However, there is a bottleneck when it comes to integrating the information from the geophysical models into the hydrological model. This transformation is difficult, because there is not a simple relationship between the hydraulic conductivity needed for the hydrological model and the electrical conductivity measured by the geophysics. In 2012 the Danish Council for Strategic Research has funded a large research project focusing on the problem of integrating geophysical models into hydrological models. The project involves a number of Danish research institutions, consulting companies, a water supply company, as well as foreign partners, USGS (USA), TNO (Holland) and CSIRO (Australia). In the project we will: 1. Use statistical methods to describe the spatial correlation between the geophysical and the lithological/hydrological data; 2. Develop semi-automatic or automatic methods for transforming spatially sampled geophysical data into geological- and/or groundwater-model parameter fields; 3. Develop an inversion method for large-scale geophysical surveys in which the model space is concordant with the hydrological model space 4. Demonstrate the benefits of spatially distributed geophysical data for informing and updating groundwater models and increasing the predictive power of management scenarios. 5. Develop a new receiver system for Magnetic Resonance Sounding data and further enhance the resolution capability of data from the SkyTEM system. 6. In test areas in Denmark, Holland, USA and Australia we will use data from existing airborne geophysical data, hydrological and geological data and also collect new airborne data, MRS surface and downhole data, and pump test data. The project is still in a startup phase but we already have results from two existing algorithms. The first one is an algorithm making a full joint inversion of Magnetic Resonance Sounding (MRS) data, Transient Electromagnetic Data (TEM) and pump test data. The second one is an algorithm using geostatistic and linear inverse theory to link boreholes categorized into clay and sand sequences together with electrical resistivities measured in spatially distributed soundings resulting in 3D models of clay and sand. We will present the HyGEM project and show results from the first two algorithms developed in the project.

Auken, E.

2012-12-01

121

Hydrological Modelling of a Canadian Prairie Wetland Basin  

NASA Astrophysics Data System (ADS)

The eastern Canadian Prairies are a region of cropland, pasture, woodland and wetlands. The region is characterized with many poor and internal drainage systems and large surface water storage terms, so watersheds here have proven challenging to hydrological models that assume good drainage to a stream. The cold climate means that snow redistribution, snowmelt and infiltration to frozen soils are important in regulating runoff generation. The Cold Regions Hydrological Modelling platform (CRHM) is an assembly system to create physically based, flexible, object oriented models. It was used to develop a prairie hydrological model to simulate the hydrological cycling in prairie watersheds and eventually the impact of land use and wetland change on hydrology. Smith Creek Basin (˜445 km2) was divided into five sub- basins, and a modelling feature - 'Groups' or representative basins was applied to model these sub-basins. Within each sub-basin, seven hydrological response units (HRUs): fallow, stubble, grassland, river channel, open water, woodland, and wetland were derived from supervised classification of SPOT 5 imagery. Physically based modules were sequentially assembled in CRHM and applied to all HRUs to simulate hydrological processes, including redistribution of snow by wind, snowmelt, infiltration, evaporation, soil moisture balance, wetland storage and runoff routing. Almost all parameters were set from values determined by remote sensing or field observations; however calibration was used to determine upland depressional storage capacity which could not be measured. Model performance in simulating snow accumulation during the winter of 2007-08 and the subsequent spring freshet was evaluated. Results show the model had generally good performance in estimating snow accumulation, with Root Mean Square Difference (RMSD) ranging from 1.8 mm to 7.9 mm for fallow, stubble, open water and woodland HRUs. Grassland, river channel and wetland HRUs had moderately large values of RMSD, ranging from 6.4 mm to 18.1 mm. The model estimated springtime basin streamflow fairly well; RMSD and Model Bias (MB) were 0.16 m3/s and -0.22, respectively. The model was also tested on an extremely wet year, 1995, and a drought year 2002. In the wet year, wetland storage was nearly full at the time of snowmelt; in the drought year wetland storage was severely depleted. The model showed satisfactory performance in both years though parameter uncertainty was affected by the lack of intense field observations.

Fang, X.; Pomeroy, J.; Brown, T.; Guo, X.; Westbrook, C.

2009-05-01

122

HBV life cycle is restricted in mouse hepatocytes expressing human NTCP.  

PubMed

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

2014-03-01

123

HBV Genotypic Variability in Cuba  

PubMed Central

The genetic diversity of HBV in human population is often a reflection of its genetic admixture. The aim of this study was to explore the genotypic diversity of HBV in Cuba. The S genomic region of Cuban HBV isolates was sequenced and for selected isolates the complete genome or precore-core sequence was analyzed. The most frequent genotype was A (167/250, 67%), mainly A2 (149, 60%) but also A1 and one A4. A total of 77 isolates were classified as genotype D (31%), with co-circulation of several subgenotypes (56 D4, 2 D1, 5 D2, 7 D3/6 and 7 D7). Three isolates belonged to genotype E, two to H and one to B3. Complete genome sequence analysis of selected isolates confirmed the phylogenetic analysis performed with the S region. Mutations or polymorphisms in precore region were more common among genotype D compared to genotype A isolates. The HBV genotypic distribution in this Caribbean island correlates with the Y lineage genetic background of the population, where a European and African origin prevails. HBV genotypes E, B3 and H isolates might represent more recent introductions. PMID:25742179

Loureiro, Carmen L.; Aguilar, Julio C.; Aguiar, Jorge; Muzio, Verena; Pentón, Eduardo; Garcia, Daymir; Guillen, Gerardo; Pujol, Flor H.

2015-01-01

124

Physical Modeling of Hydrologic Processes in South Central Texas  

NASA Astrophysics Data System (ADS)

Flood magnitude and recurrence modeling and analysis play an important role in water resources planning, management, and permitting. In both urban and rural situations, flood analysis is important to flood plain mapping and the development of best management practices for both environmental and engineering concerns. The majority of annual precipitation in South Texas results from extreme, large storm events, which produce flash floods (the number one cause of weather-related deaths in Texas). Surface geology such as such as Edward out crop faulting zone at Balcones escarpment has different properties than the classified soil; affect the soil parameters such as infiltration or hydraulic conductivity. This result in a very high infiltration and channel loss as a recharge component to the Edward aquifer from the surface runoff and rivers that are crossing the recharge zone, such as Nueces, San Antonio, Guadalupe and Colorado Rivers. Water quality is another issue in hydrological modeling, specifically in south central Texas. Water quality assessment is another issue on hydrological modeling in south central Texas. SWAT Soil and water assessment tool model is used for water quality assessment in San Antonio River basin since the rainfall runoff simulation is a necessity to derive the surface water quality process especially in the streams. With the advances in the Geographical information system (GIS) and instant precipitation products such as next generation radar (NEXRAD) and data acquisition for these products, the accuracy of the hydrological models has improved. Different hydrological models were used to evaluate the surface water and other hydrological cycle components in different watersheds in south central Texas through different events and their different causes and effects in these watersheds. Some of them are semi distributed and lumped models such as Soil and Water Assessment Tool (SWAT), Hydrologic Modeling System (HEC-HMS) and physically based distributed model Girded Surface Subsurface Hydrologic Assessment GSSHA taking the advances of GIS, NEXRAD product, remote sensing and other product such as gridded land use and soil map to achieve the highest accuracy of these models.

El Hassan, A.; Sharif, H.; Xie, H.; Terrance, J.; Mcclelland, J.

2012-04-01

125

Flash flood modeling with the MARINE hydrological distributed model  

NASA Astrophysics Data System (ADS)

Flash floods are characterized by their violence and the rapidity of their occurrence. Because these events are rare and unpredictable, but also fast and intense, their anticipation with sufficient lead time for warning and broadcasting is a primary subject of research. Because of the heterogeneities of the rain and of the behavior of the surface, spatially distributed hydrological models can lead to a better understanding of the processes and so on they can contribute to a better forecasting of flash flood. Our main goal here is to develop an operational and robust methodology for flash flood forecasting. This methodology should provide relevant data (information) about flood evolution on short time scales, and should be applicable even in locations where direct observations are sparse (e.g. absence of historical and modern rainfalls and streamflows in small mountainous watersheds). The flash flood forecast is obtained by the physically based, space-time distributed hydrological model "MARINE'' (Model of Anticipation of Runoff and INondations for Extreme events). This model is presented and tested in this paper for a real flash flood event. The model consists in two steps, or two components: the first component is a "basin'' flood module which generates flood runoff in the upstream part of the watershed, and the second component is the "stream network'' module, which propagates the flood in the main river and its subsidiaries. The basin flash flood generation model is a rainfall-runoff model that can integrate remotely sensed data. Surface hydraulics equations are solved with enough simplifying hypotheses to allow real time exploitation. The minimum data required by the model are: (i) the Digital Elevation Model, used to calculate slopes that generate runoff, it can be issued from satellite imagery (SPOT) or from French Geographical Institute (IGN); (ii) the rainfall data from meteorological radar, observed or anticipated by the French Meteorological Service (Météo France); and (iii) the spatially distributed soil and other surface properties viewed from space (land cover map from SPOT or LANDSAT, main rivers, ...). The stream flood propagation model simulates flood propagation in main rivers by solving 1-D Saint Venant equations. The data required for this part of the model are the river morphology, topography and roughness. The MARINE model has already been used previously for real time flash floods forecasting in the frame of the PACTES project on "forecasting and anticipation of floods with spatial techniques'' (funded by the CNES and the French Ministry of Research) concerning the catastrophic 1999 flash flood that occurred in the South of France. The main advantages of MARINE are its ability to run on insufficiently gauged basins (with the help of satellite information) and to run in an operational mode for real-time flood forecasting.

Estupina-Borrell, V.; Dartus, D.; Ababou, R.

2006-11-01

126

Calibration of conceptual hydrological models revisited: 1. Overcoming numerical artefacts  

NASA Astrophysics Data System (ADS)

Conceptual hydrological modelling has traditionally been plagued by calibration difficulties due to the roughness and complex shape of objective functions. These problems led to the abandonment of powerful classical analysis methods (Newton-type optimisation, derivative-based uncertainty analysis) and have motivated extensive research into nonsmooth optimisation and even new parameter estimation philosophies (e.g. GLUE). This paper shows that some of these complexities are not inherent features of hydrological models, but are numerical artefacts due to model thresholds and poorly selected time stepping schemes. We present a numerically robust methodology for implementing conceptual models, including rainfall-runoff and snow models, that ensures micro-scale smoothness of objective functions and guarantees macro-scale model stability. The methodology employs robust and unconditionally stable time integration of the models, complemented by careful threshold smoothing. A case study demonstrates the benefits of these techniques.

Kavetski, Dmitri; Kuczera, George; Franks, Stewart W.

2006-03-01

127

Advances in Parameter Estimation and Data Assimilation for Hydrologic Modeling  

NASA Astrophysics Data System (ADS)

In the past two decades, the availability of new data sources (particularly remotely sensed information) and improved computational tools has resulted in significant developments in the field of hydrologic modeling, from simple flow models to complex numerical models which simulate the coupled behavior of multiple fluxes (hydrologic, chemical, energy, etc.). At the same time, significant improvements have taken place in the data assimilation and parameter estimation methods. Although the increasing complexity of models has outpaced the development of appropriate systems identification methodologies, there is a need to design models that are properly constrained by observational data. Independent and collaborative research efforts by various groups worldwide have led to improved modeling techniques, optimization methods for parameter estimation, methods for estimating predictive uncertainty, and methods for evaluating the relative merits of competing models. This talk will review some of the key developments during the past 20 years and speculate on future directions.

Sorooshian, S.

2001-12-01

128

HESS Opinions: Hydrologic predictions in a changing environment: behavioral modeling  

NASA Astrophysics Data System (ADS)

Most hydrological models are valid at most only in a few places and cannot be reasonably transferred to other places or to far distant time periods. Transfer in space is difficult because the models are conditioned on past observations at particular places to define parameter values and unobservable processes that are needed to fully characterize the structure and functioning of the landscape. Transfer in time has to deal with the likely temporal changes to both parameters and processes under future changed conditions. This remains an important obstacle to addressing some of the most urgent prediction questions in hydrology, such as prediction in ungauged basins and prediction under global change. In this paper, we propose a new approach to catchment hydrological modeling, based on universal principles that do not change in time and that remain valid across many places. The key to this framework, which we call behavioral modeling, is to assume that there are universal and time-invariant organizing principles that can be used to identify the most appropriate model structure (including parameter values) and responses for a given ecosystem at a given moment in time. These organizing principles may be derived from fundamental physical or biological laws, or from empirical laws that have been demonstrated to be time-invariant and to hold at many places and scales. Much fundamental research remains to be undertaken to help discover these organizing principles on the basis of exploration of observed patterns of landscape structure and hydrological behavior and their interpretation as legacy effects of past co-evolution of climate, soils, topography, vegetation and humans. Our hope is that the new behavioral modeling framework will be a step forward towards a new vision for hydrology where models are capable of more confidently predicting the behavior of catchments beyond what has been observed or experienced before.

Schaefli, B.; Harman, C. J.; Sivapalan, M.; Schymanski, S. J.

2011-02-01

129

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

130

Hydrologic and water quality modeling: spatial and temporal considerations  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hydrologic and water quality models are used to help manage water resources by investigating the effects of climate, land use, land management, and water management on water resources. Each water-related issue is better investigated at a specific scale, which can vary spatially from point to watersh...

131

Hydrologic and water quality models: Use, calibration, and validation  

Technology Transfer Automated Retrieval System (TEKTRAN)

This paper introduces a special collection of 22 research articles that present and discuss calibration and validation concepts in detail for hydrologic and water quality models by their developers and presents a broad framework for developing the American Society of Agricultural and Biological Engi...

132

Information and complexity measures for hydrologic model evaluation  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hydrological models are commonly evaluated through the residual-based performance measures such as the root-mean square error or efficiency criteria. Such measures, however, do not evaluate the degree of similarity of patterns in simulated and measured time series. The objective of this study was to...

133

Modeling Sensor Knowledge of a National Hydrologic Information System  

E-print Network

river basins of Spain (SAIH is the Span- ish acronym for Automatic System Information in Hydrology the model. #12;2 2 The SAIH Information System The SAIH National Program (Spanish acronym for Automatic about water flows in rivers. The SAIH system includes different types of sensors such as pluviometers

Molina, Martín

134

Modeling the Hydrologic Processes of a Permeable Pavement System  

EPA Science Inventory

A permeable pavement system can capture stormwater to reduce runoff volume and flow rate, improve onsite groundwater recharge, and enhance pollutant controls within the site. A new unit process model for evaluating the hydrologic performance of a permeable pavement system has be...

135

Remote Sensing Data and Information for Hydrological Monitoring and Modeling  

E-print Network

1 Remote Sensing Data and Information for Hydrological Monitoring and Modeling Reza Khanbilvardi Springs, MD, USA 1 Introduction Remote sensing data and information are shown great potential in supplying measurements, remote sensing based measurements are spatially averages over the pixels can appropriate

Krakauer, Nir Y.

136

The definition of hydrologic model parameters using remote sensing techniques  

NASA Technical Reports Server (NTRS)

The reported investigation is concerned with the use of Landsat remote sensing to define input parameters for an array of hydrologic models which are used to synthesize streamflow and water quality parameters in the planning or management process. The ground truth sampling and problems involved in translating the remotely sensed information into hydrologic model parameters are discussed. Questions related to the modification of existing models for compatibility with remote sensing capabilities are also examined. It is shown that the input parameters of many models are presently overdefined in terms of the sensitivity and accuracy of the model. When this overdefinition is recognized many of the models currently considered to be incompatible with remote sensing capabilities can be modified to make possible use with sensors having rather low resolutions.

Ragan, R. M.; Salomonson, V. V.

1978-01-01

137

Evaluation of hydrological model parameter transferability for simulating the impact of land use on catchment hydrology  

NASA Astrophysics Data System (ADS)

During the past decades, the use of hydrological models for predicting the impact of land use on catchment hydrology increased considerably. The performance of those models is often judged by a simple split-sample test using historical discharge series. The derived parameter values are then assumed to be identical for the new land use scenario, apart from the crop and management characteristics that are adapted to the land use under study. This paper checks the validity of this assumption in an indirect way, by evaluating the transferability of the main controlling parameters of the semi-distributed SWAT model in a stepwise fashion: within the catchment, a neighbouring catchment and a catchment under a different environmental setting. The results indicate that there is a decline in model performance when parameters are transferred in time and space. Transfer within the catchment and to a neighbouring catchment gives for the case study still a reasonable performance, yet one should be careful when exchanging parameter values between regions with a different topography, soil and land use. These factors might influence the infiltration and percolation of water and so affect the associated model parameters.

Heuvelmans, Griet; Muys, Bart; Feyen, Jan

138

Hydrological modelling in a "big data" era: a proof of concept of hydrological models as web services  

NASA Astrophysics Data System (ADS)

Dealing with the massive increase in global data availability of all sorts is increasingly being known as "big data" science. Indeed, largely leveraged by the internet, a new resource of data sets emerges that are so large and heterogeneous that they become awkward to work with. New algorithms, methods and models are needed to filter such data to find trends, test hypotheses, make predictions and quantify uncertainties. As a considerable share of the data relate to environmental processes (e.g., satellite images, distributed sensor networks), this evolution provides exciting challenges for environmental sciences, and hydrology in particular. Web-enabled models are a promising approach to process large and distributed data sets, and to provide tailored products for a variety of end-users. It will also allow hydrological models to be used as building blocks in larger earth system simulation systems. However, in order to do so we need to reconsider the ways that hydrological models are built, results are made available, and uncertainties are quantified. We present the results of an experimental proof of concept of a hydrological modelling web-service to process heterogeneous hydrological data sets. The hydrological model itself consists of a set of conceptual model routines implemented with on a common platform. This framework is linked to global and local data sets through web standards provided by the Open Geospatial Consortium, as well as to a web interface that enables an end-user to request stream flow simulations from a self-defined location. In essence, the proof-of-concept can be seen as an implementation of the "Models of Everywhere" concept introduced by Beven in 2007. Although the setup is operational and effectively simulates stream flow, we identify several bottlenecks for optimal hydrological simulation in a web-context. The major challenges we identify are related to (1) model selection; (2) uncertainty quantification, and (3) user interaction and scenario analysis. Model selection is inherent to hydrological modelling, because of the large spatial and temporal variability of processes, which inhibits the use of one optimal model structure. However, in a web context it becomes paramount that such selection is automatic, yet objective and transparent. Similarly, uncertainty quantification is a mainstream practice in hydrological modelling, but in a web-context uncertainty analysis face unprecedented challenges in terms of tracking uncertainties throughout a possibly geographically distributed workflow, as well as dealing with an extreme heterogeneity of data availability. Lastly, the ability of end-users to interact directly with hydrological models poses specific challenges in terms of mapping user scenarios (e.g., a scenario of land-use change) into the model parameter space for prediction and uncertainty quantification. The setup has been used in several scientific experiments, including the large-scale UK consortium project on an Environmental Virtual Observatory pilot.

Buytaert, Wouter; Vitolo, Claudia

2013-04-01

139

Large-scale hydrological modelling: Parameterisation of runoff generation with high-resolution topographical data  

Microsoft Academic Search

Runoff generation is one of the most important components in hydrological cycle and in hydrological models at all spatial scales. The spatial distribution of the effective storage capacity accounts largely for the non-linearity of runoff generation dynamic. Many Hydrological models account for this spatial variability of storage in terms of statistical distributions; those models are generally proven to perform well.

Lebing Gong; Sven Halldin; C.-Y. Xu

2010-01-01

140

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

141

A real-time hydrological model for flood prediction using GIS and the WWW  

E-print Network

A real-time hydrological model for flood prediction using GIS and the WWW W. Al-Sabhan *, M hydrological models used for flood nowcasting and hazard mitigation and indicate how WWW-based systems can of such a system and the requirements for interfacing model output with these users for hydrological nowcasting

Blackburn, Alan

142

Stream temperature modeling and its integration with watershed hydrologic simulation  

NASA Astrophysics Data System (ADS)

Assessments of aquatic habitat and ecosystem risk depend on reliable representation of water quality variables including stream temperature. Presented in this paper is the modeling effort by integrating stream temperature prediction with hydrologic simulations at watershed scale. In specific, the Soil and Water Assessment Tool (SWAT) was adapted as a framework of watershed hydrology simulation for the integration of two modeling approaches for stream temperature, (1) a regression relationship between air-water temperature adjusted by river discharge, and (2) a hydroclimatological model considering lumped heat contribution and exchange. A watershed-scale model accounting for landscape processes and stream connectivity would provide more flexibility and extensibility to a stream temperature predictor, and facilitate the evaluation of stream temperature effects on water quality and ecosystem health. The resultant modeling system was applied to a snowmelt-dominated mountain system in the Boise River Basin, Idaho, with a high-quality stream temperature monitoring network maintained by the U.S. Forest Service. Model evaluation was conducted at both annual and seasonal time scales. Results suggested that modeling performance was associated with the temporal variations of the hydrologic and weather conditions. Seasonally varying parameters are required for more accurate predictions of stream temperature especially for a snowmelt-driven system such as the Boise River Basin. The integrated model is anticipated to support potentially novel ecological applications including habitat assessment and recovery, as well as watershed management and planning for water quality variables sensitive to stream temperature.

Luo, Y.; Ficklin, D. L.; Stewart, I. T.; Isaak, D.

2012-12-01

143

Hydrological modelling under non-stationarity - climate change and floods  

NASA Astrophysics Data System (ADS)

Understanding and modelling climate effects on floods, often, are essential parts of developing climate adaptation strategies. The traditional scenario method of climate impact studies is problematic due to the large uncertainties which are difficult to estimate. Moreover, it is rarely clear how the uncertainties in the assumptions propagate to the results. The focus of this work is on the mechanisms to allow a more transparent assessment of cause-effect than is possible by scenarios alone. This allows us to separate changes that are likely to occur (hard facts) from changes that are possible but not supported by data evidence (soft facts). For instance, we found that some mechanisms allow us to suggest likely changes of floods with some confidence, e.g. the increase of winter floods due to higher temperatures (rising snow fall line) and the decreasing summer floods due to earlier snowmelt. We will contrast this assessment with our views on the current state of change prediction and outline the opportunities in this area of hydrologic research. Improving the understanding of hydrological processes under the current climate, focusing on why impact studies predict changes rather than on the magnitudes of the change, improving hydrologically-driven uncertainty methods, being more transparent about what we can and cannot predict and being realistic about the role of adaptation measures in the context of water management, we believe, are the cornerstones of modelling hydrological processes in a transient climate.

Bloeschl, G.; Salinas, J.; Viglione, A.; Merz, R.

2012-12-01

144

Vegetation Dynamics And Soil Moisture: Consequences For Hydrologic Modeling  

NASA Astrophysics Data System (ADS)

Current global population growth and economical development accelerates land cover conversion in many parts of the world. Introducing non-native species and woody species encroachment, with different water demands, can affect the partitioning of hydrological fluxes. The impacts on the hydrologic cycle at local to regional scales are poorly understood. The present study investigates the hydrologic implications of land use conversion from native vegetation to rubber. We first compare the vegetation dynamics of rubber (Hevea brasiliensis), a non- native specie in Southeast Asia, to the other main vegetation types in the study area. The experimental catchment, Nam Ken (69km 2), is located in the Xishuangbanna Prefecture (21 °N, 100 °E), in the south of Yunnan province in South China. From 2005 to 2006, we collected continuous records of 2 m deep soil moisture profiles in four different land covers (tea, secondary forest, grassland and rubber), and measured surface radiation in tea and rubber canopies. Our observations show that root water uptake by rubber during the dry season is controlled by the change of day-length, whereas water demand of the native vegetation starts with the arrival of the first monsoon rainfall. The different root water uptake dynamics of rubber result in distinct depletion of deeper layer soil moisture. Traditional evapotranspiration and soil moisture models are unable to simulate this specific behavior, thus a different conceptual model is needed to predict hydrologic changes due to land use conversion in the area.

Guardiola-Claramonte, M.; Troch, P. A.

2007-12-01

145

Postexposure Prophylactic Effect of Hepatitis B Virus (HBV)-Active Antiretroviral Therapy against HBV Infection  

PubMed Central

Retrospective study indicates that hepatitis B virus (HBV)-active nucleoside (nucleotide) analogues (NAs) used for antiretroviral therapy reduce the incidence of acute HBV infections in human immunodeficiency virus (HIV)-infected patients. Learning from HIV postexposure prophylaxis (PEP), we explored the possibility of using NAs in PEP following HBV exposure, if preexposure prophylaxis is feasible clinically. Using freshly isolated primary human hepatocytes cultured in vitro, we analyzed the effect of HBV-active tenofovir and lamivudine in primary HBV infection and also the effect of treatment with these NAs after HBV infection. HBV-active NAs applied from 24 h before inoculation could not prevent the secretion of hepatitis B surface antigen into the culture medium, and cessation of the NAs after inoculation allowed the cells to establish an apparent HBV infection. In contrast, hepatitis B immune globulin was able to prevent HBV infection completely. NA treatment before infection, however, can control the spread of HBV infection, as detected by immunohistochemistry. Practically, starting NA treatment within 2 days of primary HBV infection inhibited viral spread effectively, as well as preexposure treatment. We demonstrated that preexposure NA treatment was not able to prevent the acquisition of HBV infection but prevented viral spread by suppressing the production of mature progeny HBV virions. The effect of postexposure treatment within 2 days was similar to the effect of preexposure treatment, suggesting the possibility of HBV PEP using HBV-active NAs in HIV- and HBV-susceptible high-risk groups. PMID:25512419

Watanabe, Tsunamasa; Hamada-Tsutsumi, Susumu; Yokomaku, Yoshiyuki; Imamura, Junji; Sugiura, Wataru

2014-01-01

146

Distribution of HBV genotypes among HBV carriers in Benin:phylogenetic analysis and virological characteristics of HBV genotype E  

PubMed Central

AIM: To determine the distribution of Hepatitis B virus (HBV) genotypes in Benin, and to clarify the virological characteristics of the dominant genotype. METHODS: Among 500 blood donors in Benin, 21 HBsAg-positive donors were enrolled in the study. HBV genotypes were determined by enzyme immunoassay and restriction fragment length polymorphism. Complete genome sequences were determined by PCR and direct sequencing. RESULTS: HBV genotype E (HBV/E) was detected in 20/21 (95.2%), and HBV/A in 1/21 (4.8%). From the age-specific prevalence of HBeAg to anti-HBe seroconversion (SC) in 19 HBV/E subjects, SC was estimated to occur frequently in late teens in HBV/E. The comparison of four complete HBV/E genomes from HBeAg-positive subjects in this study and five HBV/E sequences recruited from the database revealed that HBV/E was distributed throughout West Africa with very low genetic diversity (nucleotide homology 96.7-99.2%). Based on the sequences in the basic core promoter (BCP) to precore region of the nine HBV/E isolates compared to those of the other genotypes, a nucleotide substitution in the BCP, G1757A, was observed in HBV/E. CONCLUSION: HBV/E is predominant in the Republic of Benin, and SC is estimated to occur in late teens in HBV/E. The specific nucleotide substitution G1757A in BCP, which might influence the virological characteristics, is observed in HBV/E. PMID:16425408

Fujiwara, Kei; Tanaka, Yasuhito; Orito, Etsuro; Ohno, Tomoyoshi; Kato, Takanobu; Sugihara, Kanji; Hasegawa, Izumi; Sakurai, Mayumi; Ito, Kiyoaki; Ozasa, Atsushi; Sakamoto, Yuko; Arita, Isao; El-Gohary, Ahmed; Benoit, Agossou; Ogoundele-Akplogan, Sophie I; Yoshihara, Namiko; Ueda, Ryuzo; Mizokami, Masashi

2005-01-01

147

Nitrogen RiskAssessment Model for Scotland:II.Hydrological transport and model testing Hydrology and Earth System Sciences, 8(2), 205219 (2004) EGU  

E-print Network

Nitrogen RiskAssessment Model for Scotland:II.Hydrological transport and model testing 205 Hydrology and Earth System Sciences, 8(2), 205219 (2004) © EGU Nitrogen Risk Assessment Model for Scotland represented within the Nitrogen Risk Assessment Model for Scotland (NIRAMS); it demonstrates their influence

Boyer, Edmond

148

Distributed hydrological model for mapping evapotranspiration using remote sensing inputs  

NASA Astrophysics Data System (ADS)

A distributed hydrological model [Wigmosta, M.S., Vail, L.W., Lettenmaier, D.P., 1994. A distributed hydrology-vegetation model for complex terrain. Water Resource Research 30 (6), 1665-1679] is further developed to simulate the detailed spatial and temporal variation patterns of evapotranspiration (ET) around a flux tower site. In addition to meteorological, topographical and soil data, the model utilizes optical remote sensing data (Landsat TM at 30 m resolution) to characterize the distributions of vegetation types and the leaf area index (LAI). The use of LAI allows process-based modeling of major hydrological processes including transpiration, precipitation interception, and evaporation from vegetation and soil. Water flows within and between five strata (overstore, understore, moss/litter, soil unsaturated zone, and soil saturated zone) are modeled on a daily basis. A moving window of nine pixels is used to consider the lateral subsurface flow. The model is applied to a small watershed of dimension of about 16 km×12 km in Saskatchewan, Canada. The temporal variations of simulated ET are compared with eddy-covariance ET measurements over a black spruce stand located within the watershed. The stand was the Old Black Spruce in the Southern Study Area during the Boreal Ecosystem-Atmosphere Study (BOREAS) in 1994. Although the black spruce site is located in a flat area with less than 1.5 m topographical variation within 150 m of the flux tower, there was about 10.5 mm water loss through saturated subsurface flow during the growing season of 1994, accounting for 5.7% of the rainfall in same period. Even though the watershed studied had gentle terrain variations, the topography had considerable influence not only on the water table but also on the soil moisture and saturated water redistribution. This suggests the importance of modeling hydrological processes as influenced by topography in mapping ET.

Chen, Jing M.; Chen, Xiaoyong; Ju, Weimin; Geng, Xiaoyuan

2005-04-01

149

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

150

Hydrologic modeling to screen potential environmental management methods for malaria vector control in Niger  

E-print Network

This paper describes the first use of Hydrology-Entomology and Malaria Transmission Simulator (HYDREMATS), a physically based distributed hydrology model, to investigate environmental management methods for malaria vector ...

Gianotti, Rebecca Louise

151

Modeling Hydrologic Response to Land Cover Change in the Inland Pacific Northwest  

Microsoft Academic Search

Although physically based hydrologic models have been applied to understand the mechanisms by which land use change affects watershed hydrology, these models are not always directly transferable from region to region. This is partly because many different mechanisms may be responsible for producing runoff alterations. Perfect fitting of the hydrograph does not necessarily mean that all the internal hydrologic mechanisms

E. Du; T. Link; J. Hubbart; J. Gravelle

2007-01-01

152

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.

153

eWaterCycle: A high resolution global hydrological model  

NASA Astrophysics Data System (ADS)

In 2013, the eWaterCycle project was started, which has the ambitious goal to run a high resolution global hydrological model. Starting point was the PCR-GLOBWB built by Utrecht University. The software behind this model will partially be re-engineered in order to enable to run it in a High Performance Computing (HPC) environment. The aim is to have a spatial resolution of 1km x 1km. The idea is also to run the model in real-time and forecasting mode, using data assimilation. An on-demand hydraulic model will be available for detailed flow and flood forecasting in support of navigation and disaster management. The project faces a set of scientific challenges. First, to enable the model to run in a HPC environment, model runs were analyzed to examine on which parts of the program most CPU time was spent. These parts were re-coded in Open MPI to allow for parallel processing. Different parallelization strategies are thinkable. In our case, it was decided to use watershed logic as a first step to distribute the analysis. There is rather limited recent experience with HPC in hydrology and there is much to be learned and adjusted, both on the hydrological modeling side and the computer science side. For example, an interesting early observation was that hydrological models are, due to their localized parameterization, much more memory intensive than models of sister-disciplines such as meteorology and oceanography. Because it would be deadly to have to swap information between CPU and hard drive, memory management becomes crucial. A standard Ensemble Kalman Filter (enKF) would, for example, have excessive memory demands. To circumvent these problems, an alternative to the enKF was developed that produces equivalent results. This presentation shows the most recent results from the model, including a 5km x 5km simulation and a proof of concept for the new data assimilation approach. Finally, some early ideas about financial sustainability of an operational global hydrological model are presented.

van de Giesen, Nick; Bierkens, Marc; Drost, Niels; Hut, Rolf; Sutanudjaja, Edwin

2014-05-01

154

Drought Analysis for River Basins, Using the Hydrological Model SIMGRO  

NASA Astrophysics Data System (ADS)

Drought is a recurring and worldwide phenomenon, with spatial and temporal characteristics that vary significantly from one region to another. Drought has major impacts on society and affects among others the environment and the economy. Impacts are likely to increase with time as societies demands higher services for water and the environment. This will even be more pronounced in the coming decades with the projected climate change, i.e. droughts are becoming more severe in large parts of the world. The prediction of droughts is an essential part of impact assessment for current and future conditions, as part of integrated land and water management. An important question is how changes in meteorological drought will propagate into hydrological droughts in terms of changes in the groundwater system or in the river flow. The objective of our study is to develop and test tools that quantify the space-time development of droughts in a river basin. The spatial aspect of a hydrological drought (spatially-distributed recharge and groundwater heads), in a river basin brings different challenges with respect to describing the characteristics of a drought, such as: onset, duration, severity and extend. We used the regional hydrological model SIMGRO as a basis to generate the necessary data for the drought analysis. SIMGRO is a distributed physically-based model that simulates regional transient saturated groundwater flow, unsaturated flow, actual evapotranspiration, sprinkler irrigation, stream flow, groundwater and surface water levels as a response to rainfall, reference evapotranspiration, and groundwater abstraction. The model is used within the GIS environment Arc-View, which enables the use of digital data, such as soil map, land use, watercourses, as input data for the model. It is also a tool for analysis, because interactively data and results can be presented, as will be shown. Droughts in different hydrological variables (recharge, groundwater heads, river flow) are identified by applying the fixed threshold concept to spatially-distributed simulated time series. The method captures the development of both the duration and the severity for the area in a drought. For the analysis we applied the model to the Taquari river basin (about 106.000 km2), which is situated in the Pantanal region, the upper part of the Paraguay River Basin, Brazil. The question we will address is: how does a hydrological drought develop and what are the spatial characteristics and what are the underlying mechanisms. Examples of the analysis will be shown that aim at a better understanding of the process involved which are essential; to assess the vulnerability of river basins for hydrological droughts.

Querner, E.; van Lanen, H.; Rhebergen, W.

2009-05-01

155

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

156

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

157

A rangeland hydrology and erosion model  

Technology Transfer Automated Retrieval System (TEKTRAN)

Soil loss rates on rangelands are considered one of the few quantitative indicators for assessing rangeland health and conservation practice effectiveness. An erosion model to predict soil loss specific for rangeland applications is needed because existing erosion models were developed from cropland...

158

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...

159

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

160

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

161

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

162

Hydrologic modeling of soil water storage in landfill cover systems  

SciTech Connect

The accuracy of modeling soil water storage by two hydrologic models, CREAMS and HELP, was tested by comparing simulation results with field measurements of soil moisture in eight experimental landfill cover systems having a range of well-defined soil profiles and vegetative covers. Regression analysis showed that CREAMS generally represented soil moisture more accurately than HELP simulations. Soil profiles that more closely resembled natural agricultural soils were more accurately modeled than highly artificial layered soil profiles. Precautions for determining parameter values for model input and for interpreting simulation results are discussed.

Barnes, F.J.; Rodgers, J.C.

1987-01-01

163

Defining prior probabilities for hydrologic model structures in UK catchments  

NASA Astrophysics Data System (ADS)

The selection of a model structure is an essential part of the hydrological modelling process. Recently flexible modeling frameworks have been proposed where hybrid model structures can be obtained by mixing together components from a suite of existing hydrological models. When sufficient and reliable data are available, this framework can be successfully utilised to identify the most appropriate structure, and associated optimal parameters, for a given catchment by maximizing the different models ability to reproduce the desired range of flow behaviour. In this study, we use a flexible modelling framework to address a rather different question: can the most appropriate model structure be inferred a priori (i.e without using flow observations) from catchment characteristics like topography, geology, land use, and climate? Furthermore and more generally, can we define priori probabilities of different model structures as a function of catchment characteristics? To address these questions we propose a two-step methodology and demonstrate it by application to a national database of meteo-hydrological data and catchment characteristics for 89 catchments across the UK. In the first step, each catchment is associated with its most appropriate model structure. We consider six possible structures obtained by combining two soil moisture accounting components widely used in the UK (Penman and PDM) and three different flow routing modules (linear, parallel, leaky). We measure the suitability of a model structure by the probability of finding behavioural parameterizations for that model structure when applied to the catchment under study. In the second step, we use regression analysis to establish a relation between selected model structures and the catchment characteristics. Specifically, we apply Classification And Regression Trees (CART) and show that three catchment characteristics, the Base Flow Index, the Runoff Coefficient and the mean Drainage Path Slope, can be used to predict which model structure is more appropriate. The study constitutes a first step to enhance the choice of model structures in hydrological modeling across regions, with potentially interesting applications for predictions in ungauged basins, that was made possible by the analyses of large datasets.

Clements, Michiel; Pianosi, Francesca; Wagener, Thorsten; Coxon, Gemma; Freer, Jim; Booij, Martijn

2014-05-01

164

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

165

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

166

Distributed parameter hydrologic modeling usinsg object-oriented simulation  

E-print Network

parameter model for use in infiltration and runoff predictions from small watersheds. The overall objective of the research was to design and implement the object structure for hydrologic simulation. Land use, soil type, slope, and aspect categories... are used to discretize a watershed and capture the heterogeneity of a watershed, maintaining the irregular geometry of the resulting polygons. Watershed map information is prepared in the Geographical Resources Analysis Support System (GRASS...

Klanika, Kenneth Ray

1994-01-01

167

Digital elevation model grid size, landscape representation, and hydrologic simulations  

Microsoft Academic Search

High-resolution digital elevation data from two small catchments in the western United States are used to examine the effect of digital elevation model (DEM) grid size on the portrayed of the land surface and hydrologic simulations. Elevation data were gridded at 2-, 4-, 10-, 30-, and 90-m scales to generate a series of simulated landscapes. Frequency distributions of slope (tanB),

Weihua Zhang; David R. Montgomery

1994-01-01

168

Understanding hydrologic partitioning: Combining mechanistic modelling with signature analysis to understand controls on hydrologic behaviour in headwater catchments  

NASA Astrophysics Data System (ADS)

Headwater streams are the most abundant portion of the river network but the least monitored. As such, we have a limited understanding of headwater stream behaviors and how they are influenced by watershed properties such as topography, geology, and vegetation. Given the lack of runoff monitoring within headwater streams, improving an understanding of how catchment properties influence hydrologic behavior is necessary for transferring information from instrumented areas to ungauged sites. We utilize this concept to understand physical controls on similarities and differences in hydrologic behavior for five adjacent sub-catchments located in the Tenderfoot Creek Experimental Forest in central Montana with variable topographies and vegetative cover. We use an uncalibrated, distributed, physically-based watershed model, the Distributed Hydrology-Soil-Vegetation Model (DHSVM) combined with global, variance-based sensitivity analysis to investigate physical controls on a range of model-predicted hydrologic behavior (i.e. states) across multiple time scales. We implement comparative hydrology to improve our understanding of headwater watershed runoff behavior within this framework by directly relating physical properties of a given catchment to process-based predictions of hydrologic behavior, i.e. signatures. We find that across different hydrologic fluxes, including streamflow, evapotranspiration, and snow water equivalent change, only a few vegetation and soil parameters control the variability in hydrologic behavior for all sub-catchments. These controls are similar at the annual and weekly scale, though parameter influence varies seasonally from wet to dry periods. Three of the five watersheds exhibited different controls on hydrologic behavior, likely resulting from past vegetation treatments and differing surficial geology within these sub-watersheds. This framework has strong potential to inform how similarities and differences in headwater watershed characteristics can influence the variability in spatially and temporally varying hydrologic signatures. We ultimately demonstrate that the influences of soil and vegetation across headwater watersheds vary, using a modeling framework to understand physical controls on hydrologic signatures at a high resolution. We suggest that this approach can especially enhance estimation of controls on headwater watershed behavior at unmonitored sites.

Wagener, Thorsten; Kelleher, Christa; Pianosi, Francesca; McGlynn, Brian

2014-05-01

169

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

170

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

171

Hydrologic effects of evapotranspiration representation in a Richards equation based distributed hydrologic model at the catchment scale  

NASA Astrophysics Data System (ADS)

Evapotranspiration (ET) is a key water budget term that is rarely evaluated in hydrologic modeling due to the scarcity of observed actual ET fluxes. However, the ET process representation within a hydrologic model is important as it affects the simulated hydrologic response. Here we illustrate how different ET representations affect both the hydrograph and the soil moisture states within MODHMS, a Richards' equation based distributed hydrologic model at the catchment scale. MODHMS, a MODFLOW based model, has a flexible modular structure that allowed testing of 4 different base case ET scenarios: two MODFLOW ET representations (linear and piece-wise linear) and one physically based ET model in two configurations. These 4 ET sub-models were applied sequentially for the case of the well-studied 10.5 ha - Tarrawarra catchment in Australia keeping the soil parameterization constant. The hydrologic response sensitivity to each of the ET sub-models parameterization was evaluated. The ET process representation chosen for use in MODHMS is important for adequately representing soil saturation areas, lateral flow and drying of the upslope areas of the catchment as well as the outflow hydrograph.

Cristea, N. C.; Burges, S. J.

2013-12-01

172

USING DIGITAL TERRAIN ANALYSIS MODELING TECHNIQUES FOR THE PARAMETERIZATION OF A HYDROLOGIC MODEL.  

Technology Transfer Automated Retrieval System (TEKTRAN)

This paper discusses the application of digital terrain analysis modeling techniques to the parameterization of a semi-distributed hydrologic model. Most current techniques for deriving physiographic parameters in watershed analyses, including those using commercial geographic information systems (...

173

Characterising the hydrological response to climate change of a remote tropical mountainous catchment: a multi-model approach  

NASA Astrophysics Data System (ADS)

Process-based conceptual rainfall-runoff models are useful to understand runoff generation at different time and spatial resolutions. Contrary to physically-based models, they do not rely much on field observations (e.g. soil physical properties) which may not be available everywhere. Instead, these mathematical tools close the water balance and predict runoff as a function of some empirical parameters. Since corresponding values are hardly measurable, modellers usually proceed to a calibration against available observations to obtain an acceptable match between observations and predictions. However, in the case of poorly monitored areas such as elevated catchments in the Andean Cordillera, good high frequency calibration data available over a long time span are scarce. Therefore, in spite of the development of multiple effective automatized calibration techniques in recent years, results remain uncertain because of the non-uniqueness of optimal parameter sets. A state-of-the-art option to cope with this predictive uncertainty is to consider ensembles of predictions rather than single ones. Furthermore, by gathering more independent parameterisations of the same processes, multi-model approaches allow a better representation of the uncertainty than multiple realisations of the same, eventually biased, model structure subjectively chosen by the modeller based on previous experience or project requirements. As a demonstration of the usefulness of this approach in scarcely-monitored areas, we present here results of an ensemble of heterogeneous rainfall-runoff models applied to the remote San Francisco (75 km2) tropical montane forest catchment, located in the southern part of Ecuador. Each of the 7 models (CHIMP, HBV-D, HBV-light, HMS, LASCAM, NAM, SWAT) is applied to simulate runoff whilst being forced by 6 increasingly uncertain meteorological data: on-site precipitation gauges record (also used for calibration), bias-corrected downscaled re-analysis (SDSM) output of the CCSM Regional Climate Model (RCM) over the first decade of the 21st century, and output of the same RCM forced by two different IPCC emission scenarios (A1B, B1) for two decades of the middle (2050-2059) and the end of the current century (2090-2099). Results show that the annual cumulative runoff and maximum flows should increase in this area during the 21st century. Furthermore, in spite of a good agreement in the timing of seasonal runoff patterns between rainfall-runoff models forced by the same input data, there is a great variability in the magnitude of predicted extreme values. The uncertainty in the RCM emission scenarios is not greater than the uncertainty between hydrological model predictions but the ensemble still allows targeting the most probable future.

Exbrayat, J.-F.; Timbe, E.; Plesca, I.; Kraft, P.; Windhorst, D.; Trachte, K.; Buytaert, W.; Breuer, L.

2012-04-01

174

Intercomparison of hydrologic processes in global climate models  

NASA Technical Reports Server (NTRS)

In this report, we address the intercomparison of precipitation (P), evaporation (E), and surface hydrologic forcing (P-E) for 23 Atmospheric Model Intercomparison Project (AMIP) general circulation models (GCM's) including relevant observations, over a variety of spatial and temporal scales. The intercomparison includes global and hemispheric means, latitudinal profiles, selected area means for the tropics and extratropics, ocean and land, respectively. In addition, we have computed anomaly pattern correlations among models and observations for different seasons, harmonic analysis for annual and semiannual cycles, and rain-rate frequency distribution. We also compare the joint influence of temperature and precipitation on local climate using the Koeppen climate classification scheme.

Lau, W. K.-M.; Sud, Y. C.; Kim, J.-H.

1995-01-01

175

Integrated hydrological SVAT model for climate change studies in Denmark  

NASA Astrophysics Data System (ADS)

In a major Danish funded research project (www.hyacints.dk) a coupling is being established between the HIRHAM regional climate model code from Danish Meteorological Institute and the MIKE SHE distributed hydrological model code from DHI. The linkage between those two codes is a soil vegetation atmosphere transfer scheme, which is a module of MIKE SHE. The coupled model will be established for the entire country of Denmark (43,000 km2 land area) where a MIKE SHE based hydrological model already exists (Henriksen et al., 2003, 2008). The present paper presents the MIKE SHE SVAT module and the methodology used for parameterising and calibrating the MIKE SHE SVAT module for use throughout the country. As SVAT models previously typically have been tested for research field sites with comprehensive data on energy fluxes, soil and vegetation data, the major challenge lies in parameterisation of the model when only ordinary data exist. For this purpose annual variations of vegetation characteristics (Leaf Area Index (LAI), Crop height, Root depth and the surface albedo) for different combinations of soil profiles and vegetation types have been simulated by use of the soil plant atmosphere model Daisy (Hansen et al., 1990; Abrahamsen and Hansen, 2000) has been applied. The MIKE SHE SVAT using Daisy generated surface/soil properties model has been calibrated against existing data on groundwater heads and river discharges. Simulation results in form of evapotranspiration and percolation are compared to the existing MIKE SHE model and to observations. To analyse the use of the SVAT model in climate change impact assessments data from the ENSEMBLES project (http://ensembles-eu.metoffice.com/) have been analysed to assess the impacts on reference evapotranspiration (calculated by the Makkink and the Penmann-Monteith equations) as well as on the individual elements in the Penmann-Monteith equation (radiation, wind speed, humidity and temperature). The differences on the hydrological impacts of characterising climate change in terms of changes in the reference evapotranspiration or in the individual climate variables have been analysed. References Abrahamsen, P., and Hansen, S. (2000) Daisy: An Open Soil-Crop-Atmosphere System Model. Environ. Model. Software 15, 313-330. Hansen, S., Jensen, H. E., Nielsen, N. E., and Svendsen, H. (1990). Daisy - soil plant atmostphere system model. Technical Report A10, Miljostyrelsen. Henriksen, H. J., Troldborg, L., Nyegaard, P., Sonnenborg, T. O., Refsgaard, J. C. and Madsen, B. (2003) Methodology for construction, calibration and validation of a national hydrological model for Denmark. Journal of Hydrology 280(1-4), 52-71. Henriksen, H. J., Troldborg, L., Hojberg, A. L. and Refsgaard, J. C. (2008) Assessment of exploitable groundwater resources of Denmark by use of ensemble resource indicators and a numerical groundwater-surface water model. Journal of Hydrology 348(1-2), 224-240.

Mollerup, M.; Refsgaard, J.; Sonnenborg, T. O.

2010-12-01

176

Hierarchical Modeling of Fen Hydrology across Multiple Scales  

NASA Astrophysics Data System (ADS)

Significantly increased groundwater withdrawals, intensive agriculture, and urbanization have caused a loss of biodiversity in wetland habitats; especially evident in groundwater dependent wetlands. An example of this phenomenon is Michigan’s prairie fens - habitats to some of the rarest and globally unique species, including the federally listed endangered species. Efforts to conserve and restore these groundwater dependent ecosystems are, however, hampered by lack of understanding of complex fen hydrology. In this paper, we investigate 10 carefully selected fen sites, with a goal to systematically improve our understanding of the underlying fen flow regimes, landscape connections, and how local and regional groundwater flow systems interact to control fen ecology. We achieve this by applying the Michigan “hierarchical” groundwater modeling system live-linked a GIS-based, statewide hydrological and ecological database.

Li, S.; Abbas, H.; Liao, H.

2010-12-01

177

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

178

Modeling Hydrologic and Vegetation Responses in Freshwater Wetlands  

NASA Astrophysics Data System (ADS)

Wetlands constitute 6 - 7 % of the Earth's land surface and provide various critical ecosystem services such as purifying the air and water, mitigating floods and droughts, and supporting wildlife habitats. Despite the importance of wetlands, they are under threat of degradation by human-induced land use changes and climate change. Even if the value of wetlands is recognized, they are often not managed properly or restored successfully due to an inadequate understanding of the ecosystems and their responses to management scenarios. A better understanding of the main components of wetlands, namely the interdependent hydrologic and vegetation systems, and the sensitivity of their responses to engineering works and climate change, is crucial for the preservation of wetlands. To assess these potential impacts, a model is developed in this study for characterizing the coupled dynamics between soil moisture and plant biomass in wetland habitats. The hydrology component of the model is based on the Richards' equation and simulates spatially-varying groundwater movement and provides information on soil moisture at different depths. The plant growth component of the model is described through an equation of the Lotka-Volterra type modified for plant growth dynamics and is adapted from published literature. The two components are coupled via transpiration and ecosystem carrying capacity for plants. Transpiration is modeled for both unsaturated and saturated zones, while the carrying capacity describes limiting oxygen and subsequent nutrient availability in the soil column as a function of water table depth. Vegetation is represented by two species characteristic of mudflat herbaceous plants ranging from facultative wetland to upland plants. The model is first evaluated using a simplified domain and the hydrological information available in the RG2 site of the Everglades wetlands region. The modeled water table fluctuations in general are comparable to field data collected on-site, indicating the potential of the model in capturing soil moisture dynamics. Further application of the model for impact assessments demonstrates that drainage of wetlands resulting in groundwater drawdown is expected to produce appreciable effects on vegetation biomass response. The model developed in this study simulates the coupled and spatially-varying groundwater movement and plant growth dynamics, which allows researchers to better understand and protect the integrated hydrologic and vegetation systems of wetlands worldwide.

Chui, Ting Fong May; Low, Swee Yang; Liong, Shie-Yui

2010-05-01

179

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

180

Hydrologic effects of fire in sagebrush plant communities: Implications for rangeland hydrology and erosion modeling  

Technology Transfer Automated Retrieval System (TEKTRAN)

Millions of dollars are spent annually in the United States mitigating fire effects on rangeland hydrology and erosion. Rangeland managers and scientists need predictive tools to simulate hydrologic processes dictating post-fire responses, assist mitigation and risk assessments, and predict post-fir...

181

Semidistributed hydrologic modeling using remotely sensed data and GIS  

NASA Astrophysics Data System (ADS)

A semi-distributed, physically based hydrologic model (called DPHM-RS) is designed to take advantage of distributed hydrologic information retrieved from various space platform and topographic information processed from Digital Terrain Elevation Data (DTED). DPHM-RS was applied to the Paddle River Basin of central Alberta which was characterized by 5 sub-basins with each sub-basin having its own land cover types and terrain features. Input data to the model included meteorological data collected from 2 meteorological towers set up at the study site, field soil moisture data, topographic information derived from DTED, and distributed hydrologic information retrieved from NOAA-AVHRR, Landsat-TM, and Radarsat SAR data. DPHM-RS was calibrated with the data of summer, 1996 and validated with data of summer, 1997 and 1998. Excellent agreements between simulated and observed runoff at the basin outlet, energy fluxes and surface temperature demonstrated that DPHM-RS is capable of modeling basin-scale hydrologic processes. This is further confirmed by logical differences in the actual evapotranspiration (ET) simulated for different land covers and by sensible temporal variations of soil moisture simulated for each sub-basin. Given that in many aspects the performance of DPHM-RS is creditable, the ET component is used, the two-source model, to assess two popular ET models, the Penman-Menteith equation and the modified Penman equation of Granger and Gray (1989) for non-saturated surface. Based on the ET simulated for several land use classes, it seems that the closed canopy assumption of Penman-Menteith is applicable to coniferous forest and agricultural lands but not to mixed forest and pasturelands of the Canadian Prairies. The modified Penman model is generally applicable under dry environment but could estimate ET that is biased under cloudy, rainy days and wet environment. From 6 scenes of Radarsat SAR images acquired for the Paddle River Basin, and 1350 soil moisture samples collected in the same days from 9 selected sites of the Basin, we demonstrated the feasibility of retrieving near-surface soil moisture from Radarsat SAR images using a linear regression and the theoretical integration equation model (IEM) of Fung et al. (1992). From these data, we also found that for a single land use, the relationship between the cross-correlation of soil moisture and inter-site distance breaks down at a distance of about 250 m.

Biftu, Getu Fana

1998-12-01

182

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

183

Remote sensing inputs to landscape models which predict future spatial land use patterns for hydrologic models  

NASA Technical Reports Server (NTRS)

A tropical forest area of Northern Thailand provided a test case of the application of the approach in more natural surroundings. Remote sensing imagery subjected to proper computer analysis has been shown to be a very useful means of collecting spatial data for the science of hydrology. Remote sensing products provide direct input to hydrologic models and practical data bases for planning large and small-scale hydrologic developments. Combining the available remote sensing imagery together with available map information in the landscape model provides a basis for substantial improvements in these applications.

Miller, L. D.; Tom, C.; Nualchawee, K.

1977-01-01

184

Calibrating hydrologic models in flow-corrected time  

NASA Astrophysics Data System (ADS)

Modeling streamflow hydrographs can be a highly complex problem, particularly due to difficulties caused by multiple dominant streamflow states, switching of dominant streamflow generation mechanisms temporally, and dynamic catchment responses to precipitation inputs based on antecedent conditions. Because of these complexities and the extreme heterogeneity that can exist within a single catchment, model calibration techniques are generally required to obtain reasonable estimates of the model parameters. Models are typically calibrated such that a best fit is determined over the entire period of simulation. In this way, each time step explicitly carries equal weight during the calibration process. Data transformations (e.g., logarithmic or square root) are a common way of modifying the calibration process by scaling the magnitude of the observations. Here we consider a data transformation that is focused on the time domain rather than the data domain. This approach, previously employed in transit time modeling literature, conceptually stretches time during high streamflows and compresses it during low streamflow periods, dynamically weighting streamflows in the time domain. The transformation, known as flow-corrected time, is designed to provide greater weight to time periods with larger hydrologic flux. Here the flow-corrected time transformation is compared to a baseline untransformed case and the commonly employed logarithmic transformation. Considering both visual and numerical (Nash-Sutcliffe efficiency) assessments, we demonstrate that over the time periods that dominate hydrologic flux the flow-corrected time transformation resulted in improved fits to the observed hydrograph.

Smith, Tyler; Marshall, Lucy; McGlynn, Brian

2014-01-01

185

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

186

Development of a Hydrologic Modeling Platform Using a Workflow Engine  

NASA Astrophysics Data System (ADS)

Hydrologic communities around the world have developed a plethora of codes in a multitude of programming languages over the past few decades in order to assess environmental processes and to predict changes in the hydrologic realm. While these codes represent a vast amount of knowledge, expertise and resources spent and also have been extremely useful for the purposes they were designed, increasingly the realization emerges that a better coordination and coupling of both models among each other and also to data sources that drive the models is essential. The emergence of the idea of community models or integrated modeling systems (such as CSDMS, ESMF, or WRF) as well as coupling frameworks (such as openMI) have opened up new ways of thinking about how to link up legacy codes or integrate them into frameworks that allow for a more holistic modeling approach than before. This paper discusses the effort that has been undertaken to utilize a workflow engine (MicroSoft’s TRIDENT system) for the purpose of designing a modeling environment that permits the seamless integration of data flows from source, to preparation (preprocessing), to ingestion, to model execution, to harvesting (postprocessing) and analysis of the generated result data through the design of workflow sequences. While this approach has the great benefit of documenting the modeling effort from A to Z so it is repeatable (this is very important for provenance) it also permits the creation and collection of actors (or activities) that can be reused by others either in the same or other workflow environments. For example, this allows for creating a number of alternative execution modules that can be linked together in a workflow sequence and then automatically compared via sets of post processing activities thus providing great time savings. We will be demonstrating how data sources can be directly tapped into via the use of web services, how they can be interpreted and prepared for model preparation (for example, to convert digital elevation model (DEM) data to a TIN and then a modeling grid for the delineated watershed), how legacy code can be integrated into the workflow, and how modular process actors van be liked to form a complex hydrologic modeling system, and how these numerical kernels can be executed. The resulting data volumes can then be stored in common data stores (such a netCDF) or be analyzed via statistical actors to automatically extract information about the generated data before it is been stored. We will address issues of scalability of these systems, and also offer an opinion on the ease of use and feasibility of a system like this for community modeling purposes.

Piasecki, M.; Lu, B.

2010-12-01

187

Using the Workflow Engine TRIDENT as a Hydrologic Modeling Platform  

NASA Astrophysics Data System (ADS)

This is an invited contribution. Hydrologic communities around the world have developed a plethora of codes in a multitude of programming languages over the past few decades in order to assess environmental processes and to predict changes in the hydrologic realm. While these codes represent a vast amount of knowledge, expertise and resources spent and also have been extremely useful for the purposes they were designed, increasingly the realization emerges that a better coordination and coupling of both models among each other and also to data sources that drive the models is essential. The emergence of the idea of community models or integrated modeling systems (such as CSDMS, ESMF, or WRF) as well as coupling frameworks (such as openMI) have opened up new ways of thinking about how to link up legacy codes or integrate them into frameworks that allow for a more holistic modeling approach than before. This paper discusses the effort that has been undertaken to utilize a workflow engine (MicroSoft's TRIDENT system) for the purpose of designing a modeling environment that permits the seamless integration of data flows from source, to preparation (preprocessing), to ingestion, to model execution, to harvesting (postprocessing) and analysis of the generated result data through the design of workflow sequences. While this approach has the great benefit of documenting the modeling effort from A to Z so it is repeatable (this is very important for provenance) it also permits the creation and collection of actors (or activities) that can be reused by others either in the same or other workflow environments. For example, this allows for creating a number of alternative execution modules that can be linked together in a workflow sequence and then automatically compared via sets of post processing activities thus providing great time savings. We will be demonstrating how data sources can be directly tapped into via the use of web services, how they can be interpreted and prepared for model preparation (for example, to convert digital elevation model (DEM) data to a TIN and then a modeling grid for the delineated watershed), how legacy code can be integrated into the workflow, and how modular process actors van be liked to form a complex hydrologic modeling system, and how these numerical kernels can be executed. The resulting data volumes can then be stored in common data stores (such a netCDF) or be analyzed via statistical actors to automatically extract information about the generated data before it is been stored. We will address issues of scalability of these systems, and also offer an opinion on the ease of use and feasibility of a system like this for community modeling purposes.

Piasecki, Michael; Lu, Bo

2010-05-01

188

Assessing spatial patterns to characterize performance in hydrological modeling  

NASA Astrophysics Data System (ADS)

In Hydrology, spatially distributed models are traditionally evaluated against a single spatially aggregated catchment scale observation in form of river discharge with the conviction that it features the correct simulation of catchment-inherent distributed variables. Recent advances in fully distributed grid based model codes, the availability of spatially distributed data (remote sensing and intensive field studies) and computational power allow a shift towards a spatial model evaluation away from the traditional aggregated evaluation. The need of this paradigm shift is demanded in literature; however no single spatial performance metric was identified yet that proofed suitable for comparing observed and simulated spatial patterns. The goal of this study is to develop and test simple and flexible metrics for assessing spatial patterns of distributed hydrological variables that go beyond global statistics. These metrics, individually or collectively can later be used as performance criteria in the calibration process of hydrological models. Observed and simulated land surface temperature, by the MODIS satellite and by MIKE SHE, a coupled and fully distributed hydrological model, respectively are used as a benchmark to test promising spatial metrics. Additionally a synthetic dataset which contains systematic temperature perturbations, e.g. a general bias or a shift/displacement of data, is generated to test strengths and weaknesses of the spatial metrics. Four quantitative methodologies for comparing spatial patterns are brought forward in this study: (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. All algorithms except (2) require subjective judgment: E.g. a distance decay function is utilized to compute the similarity values of neighborhood cells for the fuzziness of location. Therefore a web-based survey is set up where participants are asked to grade similarity of maps in the synthetic dataset. These results are used to calibrate the subjective parameters in the algorithms accordingly and to generally test how well the four algorithms can perform relative to the visual comparison.

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

2014-05-01

189

HBV and the immune response.  

PubMed

Hepatitis B virus (HBV) infection acquired in adult life is generally self-limited while chronic persistence of the virus is the prevalent outcome when infection is acquired perinatally. Both control of infection and liver cell injury are strictly dependent upon protective immune responses, because hepatocyte damage is the price that the host must pay to get rid of intracellular virus. Resolution of acute hepatitis B is associated with functionally efficient, multispecific antiviral T-cell responses which are preceded by a poor induction of intracellular innate responses at the early stages of infection. Persistent control of infection is provided by long-lasting protective memory, which is probably sustained by continuous stimulation of the immune system by trace amounts of virus which are never totally eliminated, persisting in an occult episomic form in the nucleus of liver cells even after recovery from acute infection. Chronic virus persistence is instead characterized by a lack of protective T-cell memory maturation and by an exhaustion of HBV-specific T-cell responses. Persistent exposure of T cells to high antigen loads is a key determinant of functional T-cell impairment but also other mechanisms can contribute to T-cell inhibition, including the tolerogenic effect of the liver environment. The degree of T-cell impairment is variable and its severity is related to the level of virus replication and antigen load. The antiviral T-cell function is more efficient in patients who can control infection either partially, such as inactive HBsAg carriers with low levels of virus replication, or completely, such as patients who achieve HBsAg loss either spontaneously or after antiviral therapy. Thus, understanding the features of the immune responses associated with control of infection is needed for the successful design of novel immune modulatory therapies based on the reconstitution of efficient antiviral responses in chronic HBV patients. PMID:25529097

Ferrari, Carlo

2015-01-01

190

An Integrated Hydrologic Bayesian Multi-Model Combination Framework: Confronting Input, parameter and model structural uncertainty in Hydrologic Prediction  

SciTech Connect

This paper presents a new technique--Integrated Bayesian Uncertainty Estimator (IBUNE) to account for the major uncertainties of hydrologic rainfall-runoff predictions explicitly. The uncertainties from the input (forcing) data--mainly the precipitation observations and from the model parameters are reduced through a Monte Carlo Markov Chain (MCMC) scheme named Shuffled Complex Evolution Metropolis (SCEM) algorithm which has been extended to include a precipitation error model. Afterwards, the Bayesian Model Averaging (BMA) scheme is employed to further improve the prediction skill and uncertainty estimation using multiple model output. A series of case studies using three rainfall-runoff models to predict the streamflow in the Leaf River basin, Mississippi are used to examine the necessity and usefulness of this technique. The results suggests that ignoring either input forcings error or model structural uncertainty will lead to unrealistic model simulations and their associated uncertainty bounds which does not consistently capture and represent the real-world behavior of the watershed.

Ajami, N K; Duan, Q; Sorooshian, S

2006-05-05

191

Spatial interpolation schemes of daily precipitation for hydrologic modeling  

USGS Publications Warehouse

Distributed hydrologic models typically require spatial estimates of precipitation interpolated from sparsely located observational points to the specific grid points. We compare and contrast the performance of regression-based statistical methods for the spatial estimation of precipitation in two hydrologically different basins and confirmed that widely used regression-based estimation schemes fail to describe the realistic spatial variability of daily precipitation field. The methods assessed are: (1) inverse distance weighted average; (2) multiple linear regression (MLR); (3) climatological MLR; and (4) locally weighted polynomial regression (LWP). In order to improve the performance of the interpolations, the authors propose a two-step regression technique for effective daily precipitation estimation. In this simple two-step estimation process, precipitation occurrence is first generated via a logistic regression model before estimate the amount of precipitation separately on wet days. This process generated the precipitation occurrence, amount, and spatial correlation effectively. A distributed hydrologic model (PRMS) was used for the impact analysis in daily time step simulation. Multiple simulations suggested noticeable differences between the input alternatives generated by three different interpolation schemes. Differences are shown in overall simulation error against the observations, degree of explained variability, and seasonal volumes. Simulated streamflows also showed different characteristics in mean, maximum, minimum, and peak flows. Given the same parameter optimization technique, LWP input showed least streamflow error in Alapaha basin and CMLR input showed least error (still very close to LWP) in Animas basin. All of the two-step interpolation inputs resulted in lower streamflow error compared to the directly interpolated inputs. ?? 2011 Springer-Verlag.

Hwang, Y.; Clark, M.; Rajagopalan, B.; Leavesley, G.

2012-01-01

192

Modeling Vernal Pool Hydrology and Vegetation in the Sierra Nevadas  

NASA Astrophysics Data System (ADS)

Vernal pools are geographic depressions with relatively impermeable substrates that are subject to four distinct seasons in mountainous regions: they fill with snow in the winter, melt into inundated pools in the spring, become unsaturated and vegetated by summer, then dry and become fully desiccated by fall. Vernal pools in California are greatly threatened. Over 90% of the pools in California have been destroyed by urbanization and other land use changes and continue to disappear with population growth. Furthermore, these pools face threats posed by climate change due to altered precipitation and temperature regimes. In the context of anthropogenic climate change, we are evaluating the direct and indirect effects of grazing management on ecohydrology and plant community structure in vernal pools Northern Sierra Nevada mountains. Hydrologic models of vernal pool basins, driven by climatic variables, are used to 1) determine if a changing climate will alter the magnitude and spatial distribution of inundation period within the pools; 2) determine how the available habitat for vernal pool vegetation specialists will change with climate change; 3) determine if increased soil compaction due to cattle grazing can help mitigate effects of climate change resulting from changes in hydraulic conductivity; and 4) determine the importance of spatial resolution in constructing the physical representation of the pools within the hydrologic models. Preliminary results from the models including calibration error metrics and hydroperiod impacts of grazing for models with varying spatial complexity will be presented.

Montrone, A. K.; Saito, L.; Weisberg, P.; Gosejohan, M.

2012-12-01

193

Characterizing components of uncertainty in hydrologic modeling using an ensemble approach  

Microsoft Academic Search

In hydrologic modeling, uncertainties are known to reside in model inputs, i.e., rainfall estimates, model parameters, observations of streamflow, and in some cases in the model structure itself. Estimation of the total prediction uncertainty for a hydrologic forecast first requires knowledge of the error characteristics of input rainfall estimates. Traditionally, evaluation of quantitative precipitation estimates (QPEs) has been accomplished by

Jonathan Joseph Gourley

2003-01-01

194

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

195

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

196

The Coupling and Modeling of Eco-hydrological Processes in the Upper Reaches of Heihe River  

NASA Astrophysics Data System (ADS)

Developing new watershed models to couple the ecological, hydrological and social-economical processes for improving the understanding and regulation ability of the processes involved in water resources generation and transformation in the inland watersheds, is one important general scientific target of the NSFC Major Plan of "Integrated Research on the Eco-Hydrological Processes of Heihe Basin". With aims at this scientific target, the proposed research project will carry out a multi-scales and multi-processes study on eco-hydrology in the upper reaches of the Heihe River, identify the key eco-hydrological processes in the study region, develop a distributed eco-hydrological model for this region, and build a data assimilation and uncertainty analysis system for the developed model. Then this model will be used to assess the impacts of climate change and human activity on the runoff in the upper reaches of Heihe River. This study will improve the ability in simulating and predicting the runoff responses to environment changes in this basin, and also to promote the realization of the target of the NSFC Major Plan. This project will focus on the following three major researches: 1) the identification of key eco-hydrological processes and the overall structure designing of eco-hydrological model; 2) the development of distributed eco-hydrological watershed model; 3) the simulation and prediction of the eco-hydrological changes in the upper reaches of Heihe River. Through this study, it is expected to establish a benchmark eco-hydrological model for the mountainous watersheds with arid-cold climate and high elevation, where there are the most complex landscape, closely coupled ecological and hydrological system, and the most comprehensive hydrological processes. Also a breakthrough in the simulation of coupled eco-hydrological processes is expected.

Yang, Dawen; Cong, Zhentao; Yang, Hanbo

2013-04-01

197

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

198

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...

199

Modeling Hydrologic Response to Land Cover Change in the Inland Pacific Northwest  

NASA Astrophysics Data System (ADS)

Although physically based hydrologic models have been applied to understand the mechanisms by which land use change affects watershed hydrology, these models are not always directly transferable from region to region. This is partly because many different mechanisms may be responsible for producing runoff alterations. Perfect fitting of the hydrograph does not necessarily mean that all the internal hydrologic mechanisms have been accurately simulated. A detailed study has been designed to validate internal watershed mechanisms simulated by the Distributed Hydrology Soil Vegetation Model (DHSVM), to assess the hydrologic effects of land use change an interior Pacific Northwest experimental watershed. Hydrological measurements in the experimental area include streamflow, snowpack properties, canopy throughfall, soil moisture, and sap flow to assess the simulated hydrologic components, and hence the model's ability of predict the effects of land cover change. Model simulations span a 5-year pre-treatment, 4-year post-road construction without harvesting, and 5-year post-treatment period to ensure that the model parameterizations accurately quantify the effects of land cover alteration. The validated model was used to make a retrospective simulation of when the entire watershed was clear-cut to predict historical flow regimes. The historical fully clear-cut scenario was then used to provide a baseline to compare to contemporary harvest patterns characterized by sequential canopy removal and regrowth over smaller spatial units. Preliminary modeling results will be presented to illustrate the capability of hydrology model in predicting and forecasting hydrological responses to a range of contemporary forest practices.

Du, E.; Link, T.; Hubbart, J.; Gravelle, J.

2007-12-01

200

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

201

Epidemiology of HBV subgenotypes D.  

PubMed

The natural history of hepatitis B virus infection is not uniform and affected from several factors including, HBV genotype. Genotype D is a widely distributed genotype. Among genotype D, several subgenotypes differentiate epidemiologically and probably clinically. D1 is predominant in Middle East and North Africa, and characterized by early HBeAg seroconversion and low viral load. D2 is seen in Albania, Turkey, Brazil, western India, Lebanon, and Serbia. D3 was reported from Serbia, western India, and Indonesia. It is a predominant subgenotype in injection drug use-related acute HBV infections in Europe and Canada. D4 is relatively rare and reported from Haiti, Russia and Baltic region, Brazil, Kenya, Morocco and Rwanda. Subgenotype D5 seems to be common in Eastern India. D6 has been reported as a rare subgenotype from Indonesia, Kenya, Russia and Baltic region. D7 is the main genotype in Morocco and Tunisia. D8 and D9 are recently described subgenotypes and reported from Niger and India, respectively. Subgenotypes of genotype D may have clinical and/or viral differences. More subgenotype studies are required to conclude on subgenotype and its clinical/viral characteristics. PMID:25037178

Ozaras, Resat; Inanc Balkan, Ilker; Yemisen, Mucahit; Tabak, Fehmi

2015-02-01

202

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

203

Techniques to Access Databases and Integrate Data for Hydrologic Modeling  

SciTech Connect

This document addresses techniques to access and integrate data for defining site-specific conditions and behaviors associated with ground-water and surface-water radionuclide transport applicable to U.S. Nuclear Regulatory Commission reviews. Environmental models typically require input data from multiple internal and external sources that may include, but are not limited to, stream and rainfall gage data, meteorological data, hydrogeological data, habitat data, and biological data. These data may be retrieved from a variety of organizations (e.g., federal, state, and regional) and source types (e.g., HTTP, FTP, and databases). Available data sources relevant to hydrologic analyses for reactor licensing are identified and reviewed. The data sources described can be useful to define model inputs and parameters, including site features (e.g., watershed boundaries, stream locations, reservoirs, site topography), site properties (e.g., surface conditions, subsurface hydraulic properties, water quality), and site boundary conditions, input forcings, and extreme events (e.g., stream discharge, lake levels, precipitation, recharge, flood and drought characteristics). Available software tools for accessing established databases, retrieving the data, and integrating it with models were identified and reviewed. The emphasis in this review was on existing software products with minimal required modifications to enable their use with the FRAMES modeling framework. The ability of four of these tools to access and retrieve the identified data sources was reviewed. These four software tools were the Hydrologic Data Acquisition and Processing System (HDAPS), Integrated Water Resources Modeling System (IWRMS) External Data Harvester, Data for Environmental Modeling Environmental Data Download Tool (D4EM EDDT), and the FRAMES Internet Database Tools. The IWRMS External Data Harvester and the D4EM EDDT were identified as the most promising tools based on their ability to access and retrieve the required data, and their ability to integrate the data into environmental models using the FRAMES environment.

Whelan, Gene; Tenney, Nathan D.; Pelton, Mitchell A.; Coleman, Andre M.; Ward, Duane L.; Droppo, James G.; Meyer, Philip D.; Dorow, Kevin E.; Taira, Randal Y.

2009-06-17

204

A high-resolution European dataset for hydrologic modeling  

NASA Astrophysics Data System (ADS)

There is an increasing demand for large scale hydrological models not only in the field of modeling the impact of climate change on water resources but also for disaster risk assessments and flood or drought early warning systems. These large scale models need to be calibrated and verified against large amounts of observations in order to judge their capabilities to predict the future. However, the creation of large scale datasets is challenging for it requires collection, harmonization, and quality checking of large amounts of observations. For this reason, only a limited number of such datasets exist. In this work, we present a pan European, high-resolution gridded dataset of meteorological observations (EFAS-Meteo) which was designed with the aim to drive a large scale hydrological model. Similar European and global gridded datasets already exist, such as the HadGHCND (Caesar et al., 2006), the JRC MARS-STAT database (van der Goot and Orlandi, 2003) and the E-OBS gridded dataset (Haylock et al., 2008). However, none of those provide similarly high spatial resolution and/or a complete set of variables to force a hydrologic model. EFAS-Meteo contains daily maps of precipitation, surface temperature (mean, minimum and maximum), wind speed and vapour pressure at a spatial grid resolution of 5 x 5 km for the time period 1 January 1990 - 31 December 2011. It furthermore contains calculated radiation, which is calculated by using a staggered approach depending on the availability of sunshine duration, cloud cover and minimum and maximum temperature, and evapotranspiration (potential evapotranspiration, bare soil and open water evapotranspiration). The potential evapotranspiration was calculated using the Penman-Monteith equation with the above-mentioned meteorological variables. The dataset was created as part of the development of the European Flood Awareness System (EFAS) and has been continuously updated throughout the last years. The dataset variables are used as inputs to the hydrological calibration and validation of EFAS as well as for establishing long-term discharge "proxy" climatologies which can then in turn be used for statistical analysis to derive return periods or other time series derivatives. In addition, this dataset will be used to assess climatological trends in Europe. Unfortunately, to date no baseline dataset at the European scale exists to test the quality of the herein presented data. Hence, a comparison against other existing datasets can therefore only be an indication of data quality. Due to availability, a comparison was made for precipitation and temperature only, arguably the most important meteorological drivers for hydrologic models. A variety of analyses was undertaken at country scale against data reported to EUROSTAT and E-OBS datasets. The comparison revealed that while the datasets showed overall similar temporal and spatial patterns, there were some differences in magnitudes especially for precipitation. It is not straightforward to define the specific cause for these differences. However, in most cases the comparatively low observation station density appears to be the principal reason for the differences in magnitude.

Ntegeka, Victor; Salamon, Peter; Gomes, Goncalo; Sint, Hadewij; Lorini, Valerio; Thielen, Jutta

2013-04-01

205

Linking hydrologic models and data: The OpenMI approach  

NASA Astrophysics Data System (ADS)

Modeling frameworks provide the ability to create open, flexible modeling systems where simulations can be constructed from a set of computational modules interlinked for a given application. Various modeling frameworks have been proposed and developed with varying degrees of success. This paper investigates a more recent modeling framework, the Open Modeling Interface (OpenMI). OpenMI, which is freely available and open source (http://www.openmi.org), was developed by a consortium of public and private organizations in Europe. Various models are either already or in the process of becoming OpenMI compliant (e.g. MIKE-SHE, HEC-RAS, and Modflow). While using OpenMI to link existing models is one application of the framework, we are interested in determining the appropriateness of OpenMI as the underlying architecture for a community based hydrologic modeling system. We investigate this question by showing how the framework would allow a simulation model and database to be coupled, how OpenMI orchestrates the communication between these two components, and how OpenMI could be expanded to accommodate models and databases that are exposed as web services. We conclude with a discussion of the advantages and disadvantages of the OpenMI modeling framework and provide a vision for how a community model might be structured using an OpenMI-based approach.

Goodall, J. L.; Robinson, B. F.; Shatnawi, F. M.; Castronova, A. M.

2007-12-01

206

Hydrologic and geochemical modeling of a karstic Mediterranean watershed  

NASA Astrophysics Data System (ADS)

The SWAT model was modified to simulate the hydrologic and chemical response of karstic systems and assess the impacts of land use management and climate change of an intensively managed Mediterranean watershed in Crete, Greece. A methodology was developed for the determination of the extended karst area contributing to the spring flow as well as the degree of dilution of nitrates due to permanent karst water volume. The modified SWAT model has been able to capture the temporal variability of both karst flow and surface runoff using high frequency monitoring data collected since 2004 in addition to long term flow time series collected since 1973. The overall hydrologic budget of the karst was estimated and its evaporative losses were calculated to be 28% suggesting a very high rate of karst infiltration. Nitrate chemistry of the karst was simulated by calibrating a dilution factor allowing for the estimation of the total karstic groundwater volume to approximately 500 million m3 of reserve water. The nitrate simulation results suggested a significant impact of livestock grazing on the karstic groundwater and on surface water quality. Finally, simulation results for a set of climate change scenarios suggested a 17% decrease in precipitation, 8% decrease in ET and 22% decrease in flow in 2030-2050 compared to 2010-2020. A validated tool for integrated water management of karst areas has been developed, providing policy makers an instrument for water management that could tackle the increasing water scarcity in the island.

Nikolaidis, N. P.; Bouraoui, F.; Bidoglio, G.

2012-01-01

207

Hydrologic and geochemical modeling of a karstic Mediterranean watershed  

NASA Astrophysics Data System (ADS)

SummaryThe SWAT model was modified to simulate the hydrologic and chemical response of karstic systems and assess the impacts of land use management and climate change of an intensively managed Mediterranean watershed in Crete, Greece. A methodology was developed for the determination of the extended karst area contributing to the spring flow as well as the degree of dilution of nitrates due to permanent karst water volume. The modified SWAT model has been able to capture the temporal variability of both karst flow and surface runoff using high frequency monitoring data collected since 2004 and long term flow time series collected since 1973. The overall hydrologic budget of the karst was estimated and its evaporative losses were calculated to be 28% suggesting a very high rate of karst infiltration. Nitrate chemistry of the karst was simulated by calibrating a dilution factor allowing for the estimation of the total karstic groundwater volume to approximately 500 million m3 of reserve water. The nitrate simulation results suggested a significant impact of livestock grazing on the karstic groundwater and on surface water quality. Finally, simulation results for a set of climate change scenarios suggested a 17% decrease in precipitation, 8% decrease in ET and 22% decrease in flow in 2030-2050 compared to 2010-2029. A tool for integrated water management of karst areas has been developed, providing policy makers an instrument for water management that could tackle the increasing water scarcity in the island.

Nikolaidis, N. P.; Bouraoui, F.; Bidoglio, G.

2013-01-01

208

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

209

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

210

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

211

There are no hydrological monsters, just models and observations with large uncertainties!  

E-print Network

1 There are no hydrological monsters, just models and observations with large uncertainties! George) There are no hydrological monsters, just models and observations with large uncertainties! Hydrol. Sci. J. 55(6), xxx ignored or treated simplistically, these errors develop into monsters that destroy our ability to model

Paris-Sud XI, Université de

212

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

213

Spatial calibration and temporal validation of flow for regional scale hydrologic modeling  

Technology Transfer Automated Retrieval System (TEKTRAN)

Physically based regional scale hydrologic modeling is gaining importance for planning and management of water resources. Calibration and validation of such regional scale model is necessary before applying it for scenario assessment. However, in most regional scale hydrologic modeling, flow validat...

214

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 canal-irrigated watersheds. The existing approaches to modeling canal irrigation use situation a hydrologic perspective. In this study, an approach is developed to model canal irrigation systems

215

Intercomparsion of global hydrological models in terms of water storage simulations  

NASA Astrophysics Data System (ADS)

Global hydrology modeling is an indispensable tool to study hydrological processes on continental scales. Furthermore, the output of global hydrological models provides an important input for studies on water availability or climate change. Until now, differences between global hydrological models are larger than predicted signals within many regions. This challenges the reliability of single model predictions. In order to understand reasons and sources of these differences, we compare the output of total water storage variations as well as groundwater, soil, snow and canopy storages simulated with three global hydrological models: the Global Land Data Assimilation System (GLDAS), the Land Dynamics model (LaD) and the WaterGAP Global Hydrology Model (WGHM). The main source of model inconsistency originates from the differences in global simulations of soil moisture. The differences between the models are mainly due to different model strategies (including the definition of storage compartments), different process formulations and errors in the input data. We suggest improving model simulations by an increased effort into research of process understandings on continental scales. Furthermore, a successful and world-wide integration of satellite observations of hydrological variables into these models is desirable to reduce uncertainties in global hydrological simulations. For instance, the GRACE (Gravity Recovery and Climate Experiment) mission depicts a useful measurement system to detect and assimilate total water storage changes on the continents.

Guentner, A.; Werth, S.

2008-12-01

216

Implications of the choice and configuration of hydrologic models on the portrayal of climate change impact  

NASA Astrophysics Data System (ADS)

Climate change studies involve several methodological choices that impact the hydrological sensitivities obtained. Among these, hydrologic model structure selection and parameter identification are particularly relevant and usually have a strong subjective component. This subjectivity is not only limited to engineering applications, but also extends to many of our research studies, resulting in problems such as missing processes in our models, inappropriate parameterizations and compensatory effects of model parameters. The goal of this research is to identify the role of model structures and parameter values on the assessment of hydrologic sensitivity to climate change. We conduct our study in three basins located in the Colorado Headwaters Region, using four different hydrologic models (PRMS, VIC, Noah and Noah-MP). We first compare both model performance and climate sensitivities using default parameterizations and parameter values calibrated with the Shuffled Complex Evolution algorithm. Our results demonstrate that calibration doesn't necessarily improve the representation of hydrological processes or decrease inter-model differences in the change of signature measures of hydrologic behavior with respect to a future climate scenario. We found that inter-model differences in hydrologic sensitivities to climate change may be larger than the climate change signal even after models have been calibrated. Results demonstrate that both model choice (after calibration) and parameter selection have important effects in the portrayal of climate change impacts, and work is ongoing to identify more robust modeling strategies that explicitly account for the subjectivity in these choices. Location of the basins of interest Hydrological models used in this study

Mendoza, P. A.; Clark, M. P.; Rajagopalan, B.; Mizukami, N.; Gutmann, E. D.

2013-12-01

217

Can global hydrological models reproduce large scale river flood regimes?  

NASA Astrophysics Data System (ADS)

River flooding remains one of the most severe natural hazards. On the one hand, major flood events pose a serious threat to human well-being, causing deaths and considerable economic damage. On the other hand, the periodic occurrence of flood pulses is crucial to maintain the functioning of riverine floodplains and wetlands, and to preserve the ecosystem services the latter provide. In many regions, river floods reveal a distinct seasonality, i.e. they occur at a particular time during the year. This seasonality is related to regionally dominant flood generating processes which can be expressed in river flood types. While in data-rich regions (esp. Europe and North America) the analysis of flood regimes can be based on observed river discharge time series, this data is sparse or lacking in many other regions of the world. This gap of knowledge can be filled by global modeling approaches. However, to date most global modeling studies have focused on mean annual or monthly water availability and their change over time while simulating discharge extremes, both floods and droughts, still remains a challenge for large scale hydrological models. This study will explore the ability of the global hydrological model WaterGAP3 to simulate the large scale patterns of river flood regimes, represented by seasonal pattern and the dominant flood type. WaterGAP3 simulates the global terrestrial water balance on a 5 arc minute spatial grid (excluding Greenland and Antarctica) at a daily time step. The model accounts for human interference on river flow, i.e. water abstraction for various purposes, e.g. irrigation, and flow regulation by large dams and reservoirs. Our analysis will provide insight in the general ability of global hydrological models to reproduce river flood regimes and thus will promote the creation of a global map of river flood regimes to provide a spatially inclusive and comprehensive picture. Understanding present-day flood regimes can support both flood risk analysis and the assessment of potential regional impacts of climate change on river flooding.

Eisner, Stephanie; Flörke, Martina

2013-04-01

218

Modelling of green roof hydrological performance for urban drainage applications  

NASA Astrophysics Data System (ADS)

Green roofs are being widely implemented for stormwater management and their impact on the urban hydrological cycle can be evaluated by incorporating them into urban drainage models. This paper presents a model of green roof long term and single event hydrological performance. The model includes surface and subsurface storage components representing the overall retention capacity of the green roof which is continuously re-established by evapotranspiration. The runoff from the model is described through a non-linear reservoir approach. The model was calibrated and validated using measurement data from 3 different extensive sedum roofs in Denmark. These data consist of high-resolution measurements of runoff, precipitation and atmospheric variables in the period 2010-2012. The hydrological response of green roofs was quantified based on statistical analysis of the results of a 22-year (1989-2010) continuous simulation with Danish climate data. The results show that during single events, the 10 min runoff intensities were reduced by 10-36% for 5-10 years return period and 40-78% for 0.1-1 year return period; the runoff volumes were reduced by 2-5% for 5-10 years return period and 18-28% for 0.1-1 year return period. Annual runoff volumes were estimated to be 43-68% of the total precipitation. The peak time delay was found to greatly vary from 0 to more than 40 min depending on the type of event, and a general decrease in the time delay was observed for increasing rainfall intensities. Furthermore, the model was used to evaluate the variation of the average annual runoff from green roofs as a function of the total available storage and vegetation type. The results show that even a few millimeters of storage can reduce the mean annual runoff by up to 20% when compared to a traditional roof and that the mean annual runoff is not linearly related to the storage. Green roofs have therefore the potential to be important parts of future urban stormwater management plans.

Locatelli, Luca; Mark, Ole; Mikkelsen, Peter Steen; Arnbjerg-Nielsen, Karsten; Bergen Jensen, Marina; Binning, Philip John

2014-11-01

219

The ultraviolet variability of the symbiotic star HBV 475. III - The periodicity of HBV 475  

NASA Astrophysics Data System (ADS)

The symbiotic star HBV 475 (= V1329 Cyg) shows periodic variations in its spectrum, both in flux and in the wavelength positions of the emission lines. New IUE observations, extending to the October 1985 flux maximum, allow an improved period and phase determination. The periodic variation of the line profiles are interpreted as being due to illumination effects from a hot star on a stellar wind around a cool star, the hot star moving on an elliptical orbit. This model is consistent with the line flux variations observed in this object.

Nussbaumer, H.; Vogel, M.; Schmutz, W.

1986-11-01

220

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

221

Development and comparison of Bayesian modularization method in uncertainty assessment of hydrological models  

NASA Astrophysics Data System (ADS)

With respect to model calibration, parameter estimation and analysis of uncertainty sources, different approaches have been used in hydrological models. Bayesian method is one of the most widely used methods for uncertainty assessment of hydrological models, which incorporates different sources of information into a single analysis through Bayesian theorem. However, none of these applications can well treat the uncertainty in extreme flows of hydrological models' simulations. This study proposes a Bayesian modularization method approach in uncertainty assessment of conceptual hydrological models by considering the extreme flows. It includes a comprehensive comparison and evaluation of uncertainty assessments by a new Bayesian modularization method approach and traditional Bayesian models using the Metropolis Hasting (MH) algorithm with the daily hydrological model WASMOD. Three likelihood functions are used in combination with traditional Bayesian: the AR (1) plus Normal and time period independent model (Model 1), the AR (1) plus Normal and time period dependent model (Model 2) and the AR (1) plus multi-normal model (Model 3). The results reveal that (1) the simulations derived from Bayesian modularization method are more accurate with the highest Nash-Sutcliffe efficiency value, and (2) the Bayesian modularization method performs best in uncertainty estimates of entire flows and in terms of the application and computational efficiency. The study thus introduces a new approach for reducing the extreme flow's effect on the discharge uncertainty assessment of hydrological models via Bayesian. Keywords: extreme flow, uncertainty assessment, Bayesian modularization, hydrological model, WASMOD

Li, L.; Xu, C.-Y.; Engeland, K.

2012-04-01

222

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

223

HYDROLOGIC EVALUATION OF LANDFILL PERFORMANCE (HELP) MODEL: USER'S GUIDE FOR VERSION 3  

EPA Science Inventory

The Hydrologic Evaluation of Landfill Performance (HELP) computer program is a quasi-two-dimensional hydrologic model of water movement across, into, through and out of landfills. he model accepts weather, soil and design data. andfill systems including various combinations of ve...

224

Evapotranspiration estimates from eddy covariance towers and hydrologic modeling in managed forests in  

E-print Network

Evapotranspiration estimates from eddy covariance towers and hydrologic modeling in managed forests management plays a great role in regulating the hydrological cycle, such as streamflow and evapotranspiration a r t i c l e i n f o Keywords: Evapotranspiration Eddy covariance MIKE SHE modeling Management

Noormets, Asko

225

HYDROLOGIC MODEL UNCERTAINTY ASSOCIATED WITH SIMULATING FUTURE LAND-COVER/USE SCENARIOS: A RETROSPECTIVE ANALYSIS  

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...

226

AUTOMATIC CALIBRATION OF A HYDROLOGIC MODEL FOR SIMULATING GROUNDWATER TABLE FLUCTUATIONS ON FARMS IN THE EVERGLADES  

E-print Network

AUTOMATIC CALIBRATION OF A HYDROLOGIC MODEL FOR SIMULATING GROUNDWATER TABLE FLUCTUATIONS ON FARMS; hydrologic model; groundwater table management; Everglades Agricultural Area Received 2 August 2013; Revised, utilizing an ontology-based simulation (OntoSim-Sugarcane) framework adapted to analyze ground- water table

Grunwald, Sabine

227

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

228

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

229

A distributed hydrology-vegetation model for complex terrain  

SciTech Connect

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 solar radiation, surface meteorology, soil characteristics and moisture status, and species-dependent leaf area index and stomatal resistance. Snow accumulation and ablation are modeled using an energy balance approach that includes the effects of local topography and vegetation cover. Saturated subsurface flow is modeled using a quasi three-dimensional routing scheme. The model was applied at a 180-m scale to the Middle Fork Flathead River basin in northwestern Montana. This 2900-km{sup 2}, snowmelt-dominated watershed ranges in elevation from 900 to over 3000 m. The model was calibrated using 2 years of recorded precipitation and streamflow. The model was verified against 2 additional years of runoff and against advanced very high resolution radiometer based spatial snow cover data at the 1-km{sup 2} scale. Simulated discharge showed acceptable agreement with observations. The simulated areal patterns of snow cover were in general agreement with the remote sensing observations, but were lagged slightly in time. 42 refs., 10 figs., 1 tab.

Wigmosta, M.S.; Lettenmaier, D.P. [Univ. of Washington, Seattle, WA (United States)] [Univ. of Washington, Seattle, WA (United States); Vail, L.W. [Pacific Northwest Lab., Richland, WA (United States)] [Pacific Northwest Lab., Richland, WA (United States)

1994-06-01

230

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

231

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}...

232

Simulation of hydrologic response in an arid and a humid watershed using a distributed hydrologic model system  

NASA Astrophysics Data System (ADS)

Arid and humid watersheds are likely to show different spatial and temporal variation of runoff generation and groundwater table levels. In this study, we simulate and compare hydrologic response to rainfall in both the arid Lower Virgin Valley in Nevada and the humid Meiling Watershed in southeastern China, using a physically distributed watershed model system that can incorporate spatial variability of hydraulic parameters. In the Lower Virgin Valley, precipitation, groundwater level, discharge and aquifer test data are used for the development of surface runoff and floodplain aquifer interaction model. In the Meiling Watershed, precipitation, groundwater level and discharge data will be used to model rainfall-runoff partitioning. In both watersheds, a Terrestrial Hydrology Model is used to simulate surface runoff while the USGS MODFLOW-2005 is used to simulate groundwater flow in the floodplain. The precipitation data from each watershed are used to drive simulations of hydrologic processes in response to rainfall events at a one-hour time step, which will then be validated by groundwater level data collected from the riparian areas as well as discharge from each watershed. The modeling results are used to compare the changes of floodplain water table levels in arid and humid watersheds. The developed model also provides practical tools for water management problems in both environments.

Baron, A.; Yu, Z.; Kreamer, D.; Zhu, J.

2006-12-01

233

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

234

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

235

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

236

Plug-and-Play Hydrologic Modeling: Is That Really Possible?  

NASA Astrophysics Data System (ADS)

The vision of a community of modelers that shares reusable and well-tested process components that can easily be linked together to create new models is very appealing. In this vision, trying a new method for modeling a physical process, comparing two methods from different groups or coupling two models together to do something new is painless and straightforward. Scientists get to spend more time on understanding the natural world, making predictions and analyzing model results. Students quickly learn how different approaches differ and how sensitive models are to various input parameters. They begin to understand how the whole system works instead of just one part of it. Believe it or not, this vision is on the verge of becoming a reality but we aren't quite there yet. In order for the hydrologic modeling community to achieve this vision and work together in this way it isn't necessary for us to drastically change the way we do things. However, we do need to agree on some minimum set of standards and these have mostly to do with providing standardized metadata decriptions of our models and our data sets. We already have great software tools for accommodating differences between models that allow them to be coupled and work together. These include tools for spatial regridding, time interpolation, unit conversion, format conversion and even computer language interoperability. But in order to write software that automatically invokes these tools when needed, we need standardized machine and human-readable metadata descriptions of our models and data sets. The purpose of this talk is to review some of the technical problems that have already been solved, including the tools mentioned above, and then explain why we need standardized metadata in order to achieve the vision of seamless model integration. A new standard called the CSDMS Standard Names that is being developed for the Community Surface Dynamics Modeling System (CSDMS) project to address this problem will also be introduced.

Peckham, S. D.

2012-12-01

237

The use of distributed hydrological models for the Gard 2002 Flash-Flood event.1 Analysis of associated hydrological processes2  

E-print Network

1 The use of distributed hydrological models for the Gard 2002 Flash-Flood event.1 Analysis 2010: The use of distributed hydrological models for the Gard 2002 Flash-Flood event.21 Analysis. The river bed roughness also influences the peak intensity16 and time. Soil spatial representation is shown

Paris-Sud XI, Université de

238

Effects of soil parameterization on distributed hydrologic response: Testing a distributed hydrologic model using a hypothetical reality dataset  

NASA Astrophysics Data System (ADS)

Hydrologic data scarcity and discrepancies between model scale and point measurements are often identified as the most important limitations in evaluating distributed hydrologic models. To overcome data limitation issues, we present a framework for testing and evaluating distributed hydrologic models at the catchment scale using a hypothetical reality (HR) dataset. The HR is a synthetically generated dataset using the finite element 3D fully coupled surface-subsurface Integrated Hydrology Model (VanderKwaak, 1999) that emulates the hydrologic behavior of the real Tarrawarra catchment located in southeastern Australia. The long term HR dataset is composed of continuous outflow hydrograph and internal states at 55 observation nodes for an 11-year period as well as daily snapshots of the internal states at all nodes during the six months wet period of each year. A test model, MODHMS (HydroGeoLogic, Inc, 2000, Panday and Huyakorn, 2004), is used against the HR to illustrate the framework flexibility and functionality. We use examples from the long-term simulations to show the effects of the shape of the soil moisture retention curve and saturated hydraulic conductivity Ksat on both the integrated and distributed MODHMS hydrologic responses. We consider three base cases where we use class average van Genuchten parameters from the ROSETTA database (Schaap et al., 2001) for three soil types: clay loam, loamy sand and silty clay and one common Ksat value that is within one standard deviation interval of all three classes. For each of the three base cases we then vary Ksat sequentially to the one standard deviation interval limits for each class, according to ROSETTA, to illustrate the effects of Ksat variability for the same soil water retention curve. We examine a wet period and a dry period and discuss the range of simulated hydrographs and soil moisture states that result from different MODHMS soil parameterizations, as compared with the HR. We show soil moisture patterns in the top 2cm of soil during the wet and dry periods and illustrate the variability of surface runoff production in MODHMS for the range of parameters used.

Cristea, N. C.; Kampf, S. K.; Mirus, B. B.; Loague, K.; Burges, S. J.

2010-12-01

239

Parameterization of a hydrological model using remote sensing data  

NASA Astrophysics Data System (ADS)

The alteration of land cover by humans has multiple consequences on biological systems ranging from local to global scales. The United Nations have rated land use changes as one of the major issues for the coming centuries. In Northern Germany a significant land use change can be observed since 2004, i.e. the amendment of the Renewable Energies Act. Since then, an increasing number of biogas plants have been built resulting in an increased cultivation of so-called energy crops, especially in direct neighbourhood to these plants. Conversion of land is known to alter hydrological processes such as the exchange of energy and water. To investigate the effects of land use change on the water cycle in lowland river catchments in Northern Germany, we used a series of land cover data for the Upper Stoer, a sub-catchment of the river Elbe, as the input for a hydrological model. To derive the land cover data, we applied maximum-likelihood classifications of Landsat TM data for the years 2003 and 2010. The open source model suite SWAT (Soil Water Assessment Tool) was used to model the water cycle. SWAT has proven to be a useful tool for simulating the effect of watershed processes and management practices on water resources. A comparison of the modelled and observed discharge at the outlet of the catchment (gauge Willenscharen) showed good results (Nash Sutcliffe = 0.62). However, the land use change had no measurable effect on the discharge at the outlet due to the masking influence of high groundwater levels in the catchment. Therefore focusing on the discharge at the outlet is not a suitable approach in such cases. To represent the spatial characteristics of a catchment as realistically as possible, the catchment area must be spatially discretized. The configuration used primarily within SWAT is the sub-watershed discretization scheme. This results in a loss of spatial information, which is problematic for our intended applications. Therefore we developed an alternative model interface to manage input and output data based on grid cells. This enabled us to model the changes in evapotranspiration patterns in the catchment with changing land use more realistically and to calculate the water balance for each grid cell without losing its geographic reference. Therefore, the grid cells can interact with each other and exchange matter and energy, which was not possible using the sub-watershed approach. Therefore, the grid-cell interface enables the implementation of remote sensing data to provide a spatially distributed modelling.

Oppelt, N.; Rathjens, H.; Müller, T.-L.

2012-04-01

240

Predicting hydrological signatures in ungauged catchments using spatial interpolation, index model, and rainfall-runoff modelling  

NASA Astrophysics Data System (ADS)

Understanding a catchment's behaviours in terms of its underlying hydrological signatures is a fundamental task in surface water hydrology. It can help in water resource management, catchment classification, and prediction of runoff time series. This study investigated three approaches for predicting six hydrological signatures in southeastern Australia. These approaches were (1) spatial interpolation with three weighting schemes, (2) index model that estimates hydrological signatures using catchment characteristics, and (3) classical rainfall-runoff modelling. The six hydrological signatures fell into two categories: (1) long-term aggregated signatures - annual runoff coefficient, mean of log-transformed daily runoff, and zero flow ratio, and (2) signatures obtained from daily flow metrics - concavity index, seasonality ratio of runoff, and standard deviation of log-transformed daily flow. A total of 228 unregulated catchments were selected, with half the catchments randomly selected as gauged (or donors) for model building and the rest considered as ungauged (or receivers) to evaluate performance of the three approaches. The results showed that for two long-term aggregated signatures - the log-transformed daily runoff and runoff coefficient, the index model and rainfall-runoff modelling performed similarly, and were better than the spatial interpolation methods. For the zero flow ratio, the index model was best and the rainfall-runoff modelling performed worst. The other three signatures, derived from daily flow metrics and considered to be salient flow characteristics, were best predicted by the spatial interpolation methods of inverse distance weighting (IDW) and kriging. Comparison of flow duration curves predicted by the three approaches showed that the IDW method was best. The results found here provide guidelines for choosing the most appropriate approach for predicting hydrological behaviours at large scales.

Zhang, Yongqiang; Vaze, Jai; Chiew, Francis H. S.; Teng, Jin; Li, Ming

2014-09-01

241

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

242

Possibilities of modelling of local and global hydrological changes from high-resolution Global Hydrological Model in the absolute gravity observations - the case of Józefos?aw Observatory  

NASA Astrophysics Data System (ADS)

Geodynamical use of epoch gravimetric relative and absolute observations requires the elimination of one from the most significant effect related to local and global changes of hydrological conditions. It is understood that hydrological effect is associated with changes in groundwater levels and soil moisture around the gravimetric station. In Poland, the quasi - permanent observations of gravity changes by absolute method carried out since 2005 on gravity station located in the Astronomical - Geodetic Observatory in Józefos?aw. In the poster will be shortly described measurement strategy of absolute observations and different approaches to the elimination of the local and global effects associated with changes in hydrology. This paper will discuss the results of the analysis of tidal observations relevant to the development of absolute observations - seasonal changes in barometric correction factor and differences in the locally designated tidal corrections model. Analysis of the possibility of elimination the impact of global hydrological influence is based on the model GLDAS a spatial resolution of 0.25 degree independently on a local scale and global. Józefos?aw Observatory is equipped with additional sensors linked to the monitoring of local hydrological conditions. It gives a possibility to verify the quality of modeling of hydrological changes using global models in local and global scale.

Olszak, Tomasz; Barlik, Marcin; Pachuta, Andrzej; Próchniewicz, Dominik

2014-05-01

243

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

244

The value of environmental modelling languages for building distributed hydrological models  

NASA Astrophysics Data System (ADS)

An evaluation is made of the suitability of programming languages for hydrological modellers to create distributed, process-based hydrological models. Both system programming languages and high-level environmental modelling languages are evaluated based on a list of requirements for the optimal programming language for such models. This is illustrated with a case study, implemented using the PCRaster environmental modelling language to create a distributed, process-based hydrological model based on the concepts of KINEROS-EUROSEM. The main conclusion is that system programming languages are not ideal for hydrologists who are not computer programmers because the level of thinking of these languages is too strongly related to specialized computer science. A higher level environmental modelling language is better in the sense that it operates at the conceptual level of the hydrologist. This is because it contains operators that identify hydrological processes that operate on hydrological entities, such as two-dimensional maps, three-dimensional blocks and time-series. The case study illustrates the advantages of using an environmental modelling language as compared with system programming languages in fulfilling requirements on the level of thinking applied in the language, the reusability of the program code, the lack of technical details in the program, a short model development time and learnability. The study shows that environmental modelling languages are equally good as system programming languages in minimizing programming errors, but are worse in generic application and performance. It is expected that environmental modelling languages will be used in future mainly for development of new models that can be tailored to modelling aims and the field data available.

Karssenberg, Derek

2002-10-01

245

A process-based diagnostic approach to model evaluation: Application to the NWS distributed hydrologic model  

Microsoft Academic Search

Distributed hydrological models have the potential to provide improved streamflow forecasts along the entire channel network, while also simulating the spatial dynamics of evapotranspiration, soil moisture content, water quality, soil erosion, and land use change impacts. However, they are perceived as being difficult to parameterize and evaluate, thus translating into significant predictive uncertainty in the model results. Although a priori

Koray K. Yilmaz; Hoshin V. Gupta; Thorsten Wagener

2008-01-01

246

HYDROLOGY AND SEDIMENT MODELING USING THE BASINS NON-POINT SOURCE MODEL  

EPA Science Inventory

The Non-Point Source Model (Hydrologic Simulation Program-Fortran, or HSPF) within the EPA Office of Water's BASINS watershed modeling system was used to simulate streamflow and total suspended solids within Contentnea Creek, North Carolina, which is a tributary of the Neuse Rive...

247

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

248

Soil hydrologic characterization for modeling large scale soil remediation protocols  

NASA Astrophysics Data System (ADS)

In Campania Region (Italy), the Ministry of Environment identified a National Interest Priority Sites (NIPS) with a surface of about 200,000 ha, characterized by different levels and sources of pollution. This area, called Litorale Domitio-Agro Aversano includes some polluted agricultural land, belonging to more than 61 municipalities in the Naples and Caserta provinces. In this area, a high level spotted soil contamination is moreover due to the legal and outlaw industrial and municipal wastes dumping, with hazardous consequences also on the quality of the water table. The EU-Life+ project ECOREMED (Implementation of eco-compatible protocols for agricultural soil remediation in Litorale Domizio-Agro Aversano NIPS) has the major aim of defining an operating protocol for agriculture-based bioremediation of contaminated agricultural soils, also including the use of crops extracting pollutants to be used as biomasses for renewable energy production. In the framework of this project, soil hydrologic characterization plays a key role and modeling water flow and solute transport has two main challenging points on which we focus on. A first question is related to the fate of contaminants infiltrated from stormwater runoff and the potential for groundwater contamination. Another question is the quantification of fluxes and spatial extent of root water uptake by the plant species employed to extract pollutants in the uppermost soil horizons. Given the high variability of spatial distribution of pollutants, we use soil characterization at different scales, from field scale when facing root water uptake process, to regional scale when simulating interaction between soil hydrology and groundwater fluxes.

Romano, Nunzio; Palladino, Mario; Di Fiore, Paola; Sica, Benedetto; Speranza, Giuseppe

2014-05-01

249

OBJTOP - A New Model to Simulate Hydrological Processes  

NASA Astrophysics Data System (ADS)

Object-Oriented Design (OOD) methods and the Objected-Oriented Programming (OOP) language-C++ were used to create a new version of TOPMODEL, a spatially explicit and topographically based watershed runoff model. The new model, referred to as OBJTOP, both a) realizes the benefits of the OOD and OOP compared with traditional procedural based programming, as well as b) allows for easy relaxation of four hydrological defaults in the traditional TOPMODEL scheme. The OOD and OOP benefits of OBJTOP include features of encapsulation, inheritance, reusability, and polymorphism. More pertinent to non-programmers, the OOD and OOP enable OBJTOP to efficiently simulate watersheds of any size and for any duration without redimensionalzing arrays and recompiling the source code. Further, OBJTOP provides model routines, and an interactive graphical user interface (GUI), that allows users to simulate 1) saturation excess or infiltration excess overland flow, 2) exponential or power law decay of hydraulic conductivity with depth, 3) soil topographic index or topographic index weighting of runoff likelihood, 4) multiple of single watershed simulation, and 5) with or without channel routing. This presentation will present the underlying OOD and OOP structure used to create OBJTOP and illustrate the model calibration advantages of easy relaxation of TOPMODEL assumptions.

Wang, J.; Endreny, T. A.

2002-05-01

250

Apply a hydrological model to estimate local temperature trends  

NASA Astrophysics Data System (ADS)

Continuous times series {f(x)} such as a depth of water is written f(x) = T(x)+P(x)+S(x)+C(x) in hydrological science where T(x),P(x),S(x) and C(x) are called the trend, periodic, stochastic and catastrophic components respectively. We simplify this model and apply it to the local temperature data such as given E. Halley (1693), the UK (1853-2010), Germany (1880-2010), Japan (1876-2010). We also apply the model to CO2 data. The model coefficients are evaluated by a symbolic computation by using a standard personal computer. The accuracy of obtained nonlinear curve is evaluated by the arithmetic mean of relative errors between the data and estimations. E. Halley estimated the temperature of Gresham College from 11/1692 to 11/1693. The simplified model shows that the temperature at the time rather cold compared with the recent of London. The UK and Germany data sets show that the maximum and minimum temperatures increased slowly from the 1890s to 1940s, increased rapidly from the 1940s to 1980s and have been decreasing since the 1980s with the exception of a few local stations. The trend of Japan is similar to these results.

Igarashi, Masao; Shinozawa, Tatsuya

2014-03-01

251

On the Concepts of Information Content and Likelihood in Parameter Calibration for Hydrological Simulation Models (Invited)  

NASA Astrophysics Data System (ADS)

There remains a great deal of uncertainty about appropriate uncertainty estimation in hydrological modelling. Given that hydrology is still a subject limited by the available measurement techniques; and we cannot go back in time to take better observations of the past; the issue of epistemic error in hydrological data will not go away for the foreseeable future. It is therefore necessary to find a way of allowing for robust model conditioning and more subjective treatments of potential epistemic errors in prediction. This paper offers an analysis of how the epistemic uncertainties inherent in the hydrological modelling process impact on model conditioning, hypothesis testing and forecasting. We propose an assessment of the information in hydrological data used for calibration based upon hydrological reasoning and prior to the assessment of any of the proposed hydrological models. This can then inform the evaluation of competing models and resulting prediction uncertainties. An illustration of how this information assessment might influence model conditioning is provided by an application; the rainfall-runoff modelling of a catchment in Northern England where inconsistent data for some events can introduce disinformation into the model conditioning process. The construction of the resulting prediction uncertainties is also considered.

Smith, P. J.; Beven, K.

2013-12-01

252

The risk factors of transmission after the implementation of the routine immunization among children exposed to HBV infected mothers in a developing area in northwest China.  

PubMed

We aimed to evaluate the present situation and possible risk factors of HBV transmission after the implementation of the routine immunization among children exposed to HBV infected mothers in a developing area in northwest China. Two hundred and twenty one HBsAg carrier mothers and 247 children born to them were finally recruited in Wuwei city, Gangsu province, China in 2010. Serum samples were taken from those HBsAg carrier mothers and their children. Children who had detectable HBsAg or HBV DNA were considered to be HBV infection. Conditional logistic regression model was used to identify potential risk factors of HBV mother-to-child transmission. Of the 247 children born to HBsAg carrier mothers, 8 (3.24%) were HBsAg positive, 15 (6.07%) were HBV DNA positive. The rate of HBV mother-to-child transmission was 7.29% (18/247). The univariate analysis and multivariate analysis showed that maternal HBV DNA positive (OR=4.83, 95% CI: 1.38-16.98, p=0.0140), the delayed injection of the first dose of HBV vaccine after premature birth (OR=9.73, 95% CI: 1.78-53.21, p=0.0087) and the missing use of HBV vaccine (OR=8.29, 95% CI: 1.42-48.23, p=0.0186) were significantly associated with an increased risk for HBV mother-to-child transmission. The rate of HBV infection of the children received HBV vaccine and HBIG together after birth (2.56%, 4/156) was lower than those children received HBV vaccine alone (11.39%, 9/79) (?(2)=7.83, p=0.0052). In conclusion, the rate of mother-to-child transmission of HBV was still high in the northwest of China. Besides the positivity of maternal HBV DNA and the missing of HBV vaccination after birth, the delayed injection of the first dose of HBV vaccine after premature birth was also a possible independent risk factor for HBV mother-to-child transmission. The HBV prevention and treatment guidelines should make it clear that all of the new born infants need to receive HBV vaccine injection after birth in 24 h, including the premature infants. PMID:23022150

Li, Fan; Wang, Qixia; Zhang, Lei; Su, Haixia; Zhang, Jingxia; Wang, Tingcai; Huang, Dahong; Wu, Jun; Yan, Yongping; Fan, Daiming

2012-11-19

253

The TopoFlow Hydrologic Model: A New Community Project  

NASA Astrophysics Data System (ADS)

TopoFlow is a powerful, spatially-distributed hydrologic model with a user-friendly, wizard-style point-and-click interface. It is an open-source model that was designed to be easily modified and extended by a user community of hydrologists. Its main purpose is to model many different physical processes in a watershed with the goal of accurately predicting how various hydrologic variables will evolve in time in response to climatic forcings. The streamlined graphical interface makes it easy to perform multiple runs with different settings and different methods for parameterizing various physical processes; this makes it an excellent tool for research and teaching. Time evolutions for single pixels (such as hydrographs), collections of pixels, or entire grids (as animations) are all supported as output options. The currently supported physical processes are: Snowmelt (degree-day or energy balance method), Precipitation (uniform or varying in space/time), Evapotranspiration (Priestley-Taylor or energy balance), Infiltration (Green-Ampt coming soon), Channel/overland flow (Manning or law of wall) and Darcian, multi-layer subsurface flow. For each physical process, the user selects a "method" to be used to model that process from a droplist of options, and then specifies the input data that is required for that method and the output variables that are of interest. The ability to handle springs, sinks and canals was recently added. TopoFlow is designed so that users can use existing methods, share methods with others, or add their own methods and incorporate them into the graphical user interface. A method called "None" is always available to turn off any given physical process, and cleanly-written templates are provided to simplify the task of adding new methods. Input variables may be specified as a scalar (to be distributed uniformly), a time series, a spatial grid, or a grid seqence indexed by time. Many of the physical process methods used in TopoFlow are based on those in the ARHYTHM model, as documented by Zhang et el. (2000). ARHYTHM has been validated with data for many Arctic watersheds. TopoFlow is a work in progress and we are very interested in getting other groups involved as users, testers, and developers.

Peckham, S. D.

2004-05-01

254

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

255

A comparative analysis of projected impacts of climate change on river runoff from global and catchment-scale hydrological models  

Microsoft Academic Search

We present a comparative analysis of projected impacts of climate change on river runoff from two types of distributed hydrological model, a global hydrological model (GHM) and catchment-scale hydrological models (CHM). Analyses are conducted for six catchments that are global in coverage and feature strong contrasts in spatial scale as well as climatic and developmental conditions. These include the Liard

S. N. Gosling; R. G. Taylor; N. W. Arnell; M. C. Todd

2010-01-01

256

A comparative analysis of projected impacts of climate change on river runoff from global and catchment-scale hydrological models  

Microsoft Academic Search

We present a comparative analysis of projected impacts of climate change on river runoff from two types of distributed hydrological model, a global hydrological model (GHM) and catchment-scale hydrological models (CHM). Analyses are conducted for six catchments that are global in coverage and feature strong contrasts in spatial scale as well as climatic and developmental conditions. These include the Liard

S. N. Gosling; R. G. Taylor; N. W. Arnell; M. C. Todd

2011-01-01

257

Niger River Basin - Hydrological Modeling: Inter-changeability of parameters between models versions  

NASA Astrophysics Data System (ADS)

An enhanced hydrological framework from the existing conceptual model GR2M leads to significant results in inter-changing the models parameters, using the parameters obtained during the calibration process of a first model version in the validation process of a second model version. A two parameters and three input variables' conceptual framework called SimulHyd is used to simulate the runoff of sixteen watersheds on the Niger River and its tributaries, over eighteen years to forty six years. The first parameter controls the three model input variables and the second controls its output runoff information. Between either a lumped version and a semi-distributed version or the GR2M model and SimulHyd model, a set of three significant models parameters inter-changeability are detected: SimulHyd is better in validation process after 1970 using the calibrated parameters from GR2M before 1970, in forward modeling; GR2M is better in validation process before 1970 using the calibrated parameters from SimulHyd after 1970; and in some cases the models are more efficient in validation than in calibration. The combination both of two hydrological models drifting one of the other and of two concepts of modeling are used to demonstrate a success in the synergy of four models versions to simulate more accurately the behaviors of hydrological systems. This particularity (of these models version), responding positively in models parameters importing and exporting between different models versions, can be explored in the context of the assessment of climate change impact on water resources.INTER-CHANGED PARAMETERS NON-DISTRIBUTED MODELING VS SEMI-DISTRIBUTED MODELING SimulHyd (Simulation of hydrological Systems)N-D : Non-Distributed modelingS-D : Semi-Distributed modeling

KONE, S.

2013-12-01

258

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. PMID:25438012

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

2014-01-01

259

Coupling of the simultaneous heat and water model with a distributed hydrological model and evaluation of the combined model in a cold region watershed  

Technology Transfer Automated Retrieval System (TEKTRAN)

To represent the effects of frozen soil on hydrology in cold regions, a new physically based distributed hydrological model has been developed by coupling the simultaneous heat and water model (SHAW) with the geomorphology based distributed hydrological model (GBHM), under the framework of the water...

260

Development and application of a simple hydrologic model for water simulation for a Brazilian Headwater Basin  

Technology Transfer Automated Retrieval System (TEKTRAN)

Physically based hydrologic models for watershed are important tools to support water resources management and predicting hydrologic impacts produced by land-use change. Rio Grande Basin is located in south of Minas Gerais State, and the Rio Grande is the main tributary of basin which has 2080 km2 d...

261

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

E-print Network

of the world. This is particularly relevant in arid and semiarid regions where water scarcity poses a severeORIGINAL 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

262

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

NASA Technical Reports Server (NTRS)

Methods for the reduction of remotely sensed data and its application in hydrologic land use assessment, surface water inventory, and soil property studies are presented. LANDSAT data is used to provide quantitative parameters and coefficients to construct watershed transfer functions for a hydrologic planning model aimed at estimating peak outflow from rainfall inputs.

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

1977-01-01

263

A model for simulation of the climate and hydrology of the Great Lakes basin  

E-print Network

A model for simulation of the climate and hydrology of the Great Lakes basin Brent M. Lofgren Great Lakes Environmental Research Laboratory, NOAA, Ann Arbor, Michigan, USA Received 4 February 2004 of the land hydrology of the Great Lakes basin and of the evaporation and thermodynamics of the Great Lakes

264

Evaluating Satellite-based Rainfall Estimates for Basin-scale Hydrologic Modeling  

Microsoft Academic Search

The reliability of any hydrologic simulation and basin outflow prediction effort depends primarily on the rainfall estimates. The problem of estimating rainfall becomes more obvious in basins with scarce or no rain gauges. We present an evaluation of satellite-based rainfall estimates for basin-scale hydrologic modeling with particular interest in ungauged basins. The initial phase of this study focuses on comparison

K. K. Yilmaz; T. S. Hogue; K. Hsu; H. V. Gupta; S. E. Mahani; S. Sorooshian

2003-01-01

265

The impact of groundwater-land surface interactions on hydrologic persistence in macroscale modeling  

E-print Network

The impact of groundwater-land surface interactions on hydrologic persistence in macroscale, and vegetation TEST BASINS OVERVIEW Shallow groundwater interacts with the hydrologic cycle by influencing Capacity (VIC) model does not explicitly represent shallow groundwater. This might impact an LSM's ability

Washington at Seattle, University of

266

Evapotranspiration and irrigation algorithms in hydrologic modeling:Present Status and Opportunities  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hydrologic models are used extensively for predicting water availability and water quality responses to alternative irrigation, tillage, crop, and fertilizer management practices and global climate change. Modeling results have been frequently used by regulatory agencies for developing remedial meas...

267

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...

268

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

269

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

270

Integrating fire with hydrological projections: model evaluation to identify uncertainties and tradeoffs in model complexity  

NASA Astrophysics Data System (ADS)

It is imperative for resource managers to understand how a changing climate might modify future watershed and hydrological processes, and such an understanding is incomplete if disturbances such as fire are not integrated with hydrological projections. Can a robust fire spread model be developed that approximates patterns of fire spread in response to varying topography wind patterns, and fuel loads and moistures, without requiring intensive calibration to each new study area or time frame? We assessed the performance of a stochastic model of fire spread (WMFire), integrated with the Regional Hydro-Ecological Simulation System (RHESSys), for projecting the effects of climatic change on mountain watersheds. We first use Monte Carlo inference to determine that the fire spread model is able to replicate the spatial pattern of fire spread for a contemporary wildfire in Washington State (the Tripod fire), measured by the lacunarity and fractal dimension of the fire. We then integrate a version of WMFire able to replicate the contemporary wildfire with RHESSys and simulate a New Mexico watershed over the calibration period of RHESSys (1941-1997). In comparing the fire spread model to a single contemporary wildfire we found issues in parameter identifiability for several of the nine parameters, due to model input uncertainty and insensitivity of the mathematical function to certain ranges of the parameter values. Model input uncertainty is caused by the inherent difficulty in reconstructing fuel loads and fuel moistures for a fire event after the fire has occurred, as well as by issues in translating variables relevant to hydrological processes produced by the hydrological model to those known to affect fire spread and fire severity. The first stage in the model evaluation aided the improvement of the model in both of these regards. In transporting the model to a new landscape in order to evaluate fire regimes in addition to patterns of fire spread, we find reasonable outcomes with respect to both. This two-stage model evaluation against multiple criteria and for more than one landscape demonstrates that a relatively simple model of fire spread can be sufficiently robust to simulate fire regimes for varying ecosystems and time periods. A careful model evaluation allows for identification of model uncertainties, which are then reduced by improvements to model structure. When integrating a fire spread model with a hydrological model for watershed projections it is insufficient to determine the adequacy of the fire spread module independently of the hydrological model. The integration of the two models should be assessed as vigorously as the individual modules.

Kennedy, M.; McKenzie, D.

2013-12-01

271

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

272

Simulation of flood reduction by natural river rehabilitation using a distributed hydrological model Hydrology and Earth System Sciences, 8(6), 11291140 (2004) EGU  

E-print Network

Simulation of flood reduction by natural river rehabilitation using a distributed hydrological model 1129 Hydrology and Earth System Sciences, 8(6), 11291140 (2004) © EGU Simulation of flood The effects of river rehabilitation on flood reduction in the Steinsel sub-basin of the Alzette River basin

Boyer, Edmond

273

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

274

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

275

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

276

Impact of modellers' decisions on hydrological a priori predictions  

NASA Astrophysics Data System (ADS)

The purpose of this paper is to stimulate a re-thinking of how we, the catchment hydrologists, could become reliable forecasters. A group of catchment modellers predicted the hydrological response of a man-made 6 ha catchment in its initial phase (Chicken Creek) without having access to the observed records. They used conceptually different model families. Their modelling experience differed largely. The prediction exercise was organized in three steps: (1) for the 1st prediction modellers received a basic data set describing the internal structure of the catchment (somewhat more complete than usually available to a priori predictions in ungauged catchments). They did not obtain time series of stream flow, soil moisture or groundwater response. (2) Before the 2nd improved prediction they inspected the catchment on-site and attended a workshop where the modellers presented and discussed their first attempts. (3) For their improved 3rd 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 decisions in accounting for the various processes based on what they learned during the field visit (step 2) and add the final outcome of step 3 when the modellers made use of additional data. We document the prediction progress as well as the learning process resulting from the availability of added information. For the 2nd and 3rd step, the progress in prediction quality could be evaluated in relation to individual modelling experience and costs of added information. 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.

2013-07-01

277

Activity of HBV475 from its Spectral Variations  

NASA Astrophysics Data System (ADS)

Spectroscopic analyses on HBV 475 are presented. From the data in the term between 1974-1978, it is found that (i) variations in the emission lines are caused by temperature variations of the exciting star, T*, which extend over the range 120,000?T*?180,000 K; (ii) the dimensions of the Fe+6 and He+ zones are estimated to be 7 × 1016-18 cm on the assumption that the radius of the central star is equal to the solar one. We prefer a single star model for HBV 475 in order to interpret our observational data. This hypothesis is supported by the data of line profiles which are qualitatively consistent with the interacting stellar winds model.

Tamura, S.

278

Modelling of green roofs' hydrologic performance using EPA's SWMM.  

PubMed

Green roofs significantly affect the increase in water retention and thus the management of rain water in urban areas. In Poland, as in many other European countries, excess rainwater resulting from snowmelt and heavy rainfall contributes to the development of local flooding in urban areas. Opportunities to reduce surface runoff and reduce flood risks are among the reasons why green roofs are more likely to be used also in this country. However, there are relatively few data on their in situ performance. In this study the storm water performance was simulated for the green roofs experimental plots using the Storm Water Management Model (SWMM) with Low Impact Development (LID) Controls module (version 5.0.022). The model consists of many parameters for a particular layer of green roofs but simulation results were unsatisfactory considering the hydrologic response of the green roofs. For the majority of the tested rain events, the Nash coefficient had negative values. It indicates a weak fit between observed and measured flow-rates. Therefore complexity of the LID module does not affect the increase of its accuracy. Further research at a technical scale is needed to determine the role of the green roof slope, vegetation cover and drying process during the inter-event periods. PMID:23823537

Burszta-Adamiak, E; Mrowiec, M

2013-01-01

279

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

280

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

281

Inhibition of hepatitis B virus (HBV) by LNA-mediated nuclear interference with HBV DNA transcription  

SciTech Connect

Highlights: {yields} LNA-modified oligonucleotides can pass through the plasma membrane of cultured cells even without using transfection machinery. {yields} LNA-modified oligonucleotides passed efficiently across the cell membrane, and lipid-coating facilitated translocation from the cytoplasm to the nucleus. {yields} LNA-oligonucleotide designed to target nuclear HBV DNA efficiently suppresses HBV replication and transcription in cultured hepatic cells. -- Abstract: Silencing target genes with small regulatory RNAs is widely used to investigate gene function and therapeutic drug development. Recently, triplex-based approaches have provided another attractive means to achieve targeted gene regulation and gene manipulation at the molecular and cellular levels. Nuclear entry of oligonucleotides and enhancement of their affinity to the DNA targets are key points of such approaches. In this study, we developed lipid-based transport of a locked-nucleic-acid (LNA)-modified oligonucleotide for hepatitis B virus (HBV) DNA interference in human hepatocytes expressing HBV genomic DNA. In these cells, the LNA-modified oligonucleotides passed efficiently across the cell membrane, and lipid-coating facilitated translocation from the cytoplasm to the nucleus. The oligonucleotide specifically targeting HBV DNA clearly interfered with HBV DNA transcription as shown by a block in pregenomic RNA (pgRNA) production. The HBV DNA-targeted oligonucleotide suppressed HBV DNA replication and HBV protein production more efficiently than small interfering RNAs directed to the pgRNA. These results demonstrate that fusion with lipid can carry LNA-modified oligonucleotides to the nucleus where they regulate gene expression. Interfering with HBV DNA transcription by LNA-modified oligonucleotides has strong potential as a new strategy for HBV inhibition.

Sun, Zhen [The State Key Laboratory of Genetic Engineering and The MOE Key Laboratory of Contemporary Anthropology, School of Life Science, Fudan University, Shanghai 200433 (China) [The State Key Laboratory of Genetic Engineering and The MOE Key Laboratory of Contemporary Anthropology, School of Life Science, Fudan University, Shanghai 200433 (China); Department of Biochemistry and Molecular Biology, Program in Molecular Cell Biology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058 (China); Xiang, Wenqing; Guo, Yajuan [Department of Biochemistry and Molecular Biology, Program in Molecular Cell Biology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058 (China)] [Department of Biochemistry and Molecular Biology, Program in Molecular Cell Biology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058 (China); Chen, Zhi [The State Key Laboratory for Infectious Disease, Institute of Infectious Disease, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003 (China)] [The State Key Laboratory for Infectious Disease, Institute of Infectious Disease, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003 (China); Liu, Wei, E-mail: liuwei666@zju.edu.cn [Department of Biochemistry and Molecular Biology, Program in Molecular Cell Biology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058 (China)] [Department of Biochemistry and Molecular Biology, Program in Molecular Cell Biology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058 (China); Lu, Daru, E-mail: drlu@fudan.edu.cn [The State Key Laboratory of Genetic Engineering and The MOE Key Laboratory of Contemporary Anthropology, School of Life Science, Fudan University, Shanghai 200433 (China)] [The State Key Laboratory of Genetic Engineering and The MOE Key Laboratory of Contemporary Anthropology, School of Life Science, Fudan University, Shanghai 200433 (China)

2011-06-10

282

Review of soil water models with respect to savanna hydrology   

E-print Network

Effective management leading towards sustainable rangeland production in arid and semi-arid regions will stem from effective soil water management and comprehension of the hydrological properties of the soil in relation to pastoralism. However...

Derry, Julian F; Russell, Graham; Liedloff, Adam C

2006-07-21

283

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

284

Occult HBV infection among Egyptian hepatocellular carcinoma patients  

PubMed Central

Background Occult HBV infection accelerates the progression of liver fibrosis, cirrhosis, and finally leading to hepatocellular carcinoma (HCC). This study analyzed the occult HBV-genotypes in HCC patients. Methods To achieve our objective, matched serum and tissue samples were collected from 40 HCC patients. Three sets of primers were used for the HBV-DNA detection by nested-PCR, which cover the HBV-genome; Core, Surface and X genes. Genotyping system based on PCR using type-specific primers was applied on HBV-DNA positive samples. Results Intrahepatic occult HBV-DNA was detected in 62.5%, whereas; Serum occult HBV-DNA were detected in only 22.5% of HCC patients. In patients' positive for both anti-HBs and anti-HBc, 10% had occult HBV in serum. In serologically negative HCV patients, 63% had intrahepatic HBV-DNA, and 21% had HBV-DNA in serum samples. HBV-genotype D (32%) and B (24%) attributed predominantly to intrahepatic HBV infections in HCC patients, whereas HBV-genotype A (4%) and C (8%) infections were the least observed. Conclusion This is the first study to show the genotypes of occult HBV infection in HCC Patients. We suggest that B or D may influence the outcome of HBV infection which may lead to the development of HCC. PMID:21371325

2011-01-01

285

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

286

Integrated hydrologic modeling: Effects of spatial scale, discretization and initialization  

NASA Astrophysics Data System (ADS)

Groundwater discharge contributes significantly to the annual flows of Chesapeake Bay tributaries and is presumed to contribute to the observed lag time between the implementation of management actions and the environmental response in the Chesapeake Bay. To investigate groundwater fluxes and flow paths and interaction with surface flow, we have developed a fully distributed integrated hydrologic model of the Chesapeake Bay Watershed using ParFlow. Here we present a comparison of model spatial resolution and initialization methods. We have studied the effect of horizontal discretization on overland flow processes at a range of scales. Three nested model domains have been considered: the Monocacy watershed (5600 sq. km), the Potomac watershed (92000 sq. km) and the Chesapeake Bay watershed (400,000 sq. km). Models with homogeneous subsurface and topographically-derived slopes were evaluated at 500-m, 1000-m, 2000-m, and 4000-m grid resolutions. Land surface slopes were derived from resampled DEMs and corrected using stream networks. Simulation results show that the overland flow processes are reasonably well represented with a resolution up to 2000 m. We observe that the effects of horizontal resolution dissipate with larger scale models. Using a homogeneous model that includes subsurface and surface terrain characteristics, we have evaluated various initialization methods for the integrated Monocacy watershed model. This model used several options for water table depths and two rainfall forcing methods including (1) a synthetic rainfall-recession cycle corresponding to the region's average annual rainfall rate, and (2) an initial shut-off of rainfall forcing followed by a rainfall-recession cycling. Results show the dominance of groundwater generated runoff during a first phase of the simulation followed by a convergence towards more balanced runoff generation mechanisms. We observe that the influence of groundwater runoff increases in dissected relief areas characterized by high slope magnitudes. This is due to the increase in initial water table gradients in these regions. As a result, in the domain conditions for this study, an initial shut-off of rainfall forcing proved to be the more efficient initialization method. The initialized model is then coupled with a Land Surface Model (CLM). Ongoing work includes coupling a heterogeneous subsurface field with spatially variable meteorological forcing using the National Land Data Assimilation System (NLDAS) data products. Seasonal trends of groundwater levels for current and pre-development conditions of the basin will be compared.

Seck, A.; Welty, C.; Maxwell, R. M.

2011-12-01

287

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

288

Improving statistical forecasts of seasonal streamflows using hydrological model output  

NASA Astrophysics Data System (ADS)

Statistical methods traditionally applied for seasonal streamflow forecasting use predictors that represent the initial catchment condition and future climate influences on future streamflows. Observations of antecedent streamflows or rainfall commonly used to represent the initial catchment conditions are surrogates for the true source of predictability and can potentially have limitations. This study investigates a hybrid seasonal forecasting system that uses the simulations from a dynamic hydrological model as a predictor to represent the initial catchment condition in a statistical seasonal forecasting method. We compare the skill and reliability of forecasts made using the hybrid forecasting approach to those made using the existing operational practice of the Australian Bureau of Meteorology for 21 catchments in eastern Australia. We investigate the reasons for differences. In general, the hybrid forecasting system produces forecasts that are more skilful than the existing operational practice and as reliable. The greatest increases in forecast skill tend to be (1) when the catchment is wetting up but antecedent streamflows have not responded to antecedent rainfall, (2) when the catchment is drying and the dominant source of antecedent streamflow is in transition between surface runoff and base flow, and (3) when the initial catchment condition is near saturation intermittently throughout the historical record.

Robertson, D. E.; Pokhrel, P.; Wang, Q. J.

2013-02-01

289

Integration of models for better quantification of urban hydrology: Coupling urban drainage system models and distributed groundwater models  

NASA Astrophysics Data System (ADS)

There is a growing need to simulate and predict hydrological system responses in urban environments as infrastructure becomes increasingly threatened by the effects of climate change (e.g. more frequent and severe flooding). Urban hydrology can cause flooding by drainage systems reaching maximum capacity, precipitation exceeding soil infiltration capacity, groundwater rising above surface, or a combination of these processes. The high complexity of urban hydrology is strained by the interaction between natural hydrological systems with precipitation, overland flow, recharge, groundwater flow, and drainage systems with routing of water from paved areas toward finite drainage networks. In order to asses flood risks in the urban environment, a modelling system integrating the different interacting parts in the urban hydrology should be applied. In the presented study a well-known drainage water and sewage water model, MIKE URBAN based on MOUSE is coupled with a spatially distributed groundwater - surface water model including vadoze zone processes. The primary objective for the study is to improve subsurface urban hydrological predictability because previous studies have illustrated the incapability of a stand-alone groundwater model to simulate measured groundwater head variability beneath an urbanized area. The investigated urban area is located in the western part of Denmark where urban infrastructure is vulnerable against high groundwater levels. Groundwater head predictions benefit from the coupled modelling approach where paved urban zones (with drainage runoff) and green areas (with more naturally occurring recharge) are separated, thereby affecting dynamic groundwater levels.

Kidmose, J.; Troldborg, L.; Refsgaard, J.; Randall, M. T.

2012-12-01

290

Enhancing Hydrologic Modelling in the Coupled Weather Research and Forecasting-Urban Modelling System  

NASA Astrophysics Data System (ADS)

Urbanization modifies surface energy and water budgets, and has significant impacts on local and regional hydroclimate. In recent decades, a number of urban canopy models have been developed and implemented into the Weather Research and Forecasting (WRF) model to capture urban land-surface processes. Most of these models are inadequate due to the lack of realistic representation of urban hydrological processes. Here, we implement physically-based parametrizations of urban hydrological processes into the single layer urban canopy model in the WRF model. The new single-layer urban canopy model features the integration of, (1) anthropogenic latent heat, (2) urban irrigation, (3) evaporation from paved surfaces, and (4) the urban oasis effect. The new WRF-urban modelling system is evaluated against field measurements for four different cities; results show that the model performance is substantially improved as compared to the current schemes, especially for latent heat flux. In particular, to evaluate the performance of green roofs as an urban heat island mitigation strategy, we integrate in the urban canopy model a multilayer green roof system, enabled by the physical urban hydrological schemes. Simulations show that green roofs are capable of reducing surface temperature and sensible heat flux as well as enhancing building energy efficiency.

Yang, Jiachuan; Wang, Zhi-Hua; Chen, Fei; Miao, Shiguang; Tewari, Mukul; Voogt, James A.; Myint, Soe

2015-04-01

291

Modelling hydrology and water quality in a Mediterranean catchment  

NASA Astrophysics Data System (ADS)

In this study the SWAT model has been used in order to analyse and quantify pollution dynamics at basin scale depending on concentrated and diffuse sources. Nowadays, the receiving water bodies quality safeguarding is of growing importance due to the promulgation of recent laws as well as the growing sensitivity regarding the environment issues by the scientific and practitioner committee. Recently the EU 2000/60 (Water Framework Directive) makes the analysis of receiving water bodies even more complex by integrating the pollution in urban areas in a framework of the pollution sources at catchment scale. and making necessary further integration of environmental impacts associated with discharges concentrates civilian and productive with the widespread pollution linked mainly to agriculture and zoo-technical activities. The complexity of natural systems and the large number of polluting sources and variables to be monitored requires the adoption of models able to get a better view of the whole system in a simplified way without neglecting the most important physical phenomena. Particularly, in this study the SWAT model was considered since it is an integrated hydrological model that are, nowadays, needed to support the implementation of integrated water management plans and to comply with the current requirements of the WFD. In addition, the SWAT model is interfaced with the ARC-VIEW software which allows easy pre-and post processing of the spatially distributed input data, driving the rainfall-runoff process. The model has been applied to the experimental Nocella catchment located in Sicily (Italy), with an area of about 50 km2. The river receives wastewater and stormwater from two urban areas drained by combined sewers. The study demonstrates that the analysis of water quality in partially urbanised natural basins is complex depending on variable polluting contributions of the different parts of the system depending on specific polluting compounds. The model was calibrated and then validated, obtaining satisfactory performance. The estimation of loads from diffuse sources was difficult due to limited data availability. Thus, it was only possible to include constant diffuse pollution concentrations at present. In spite of these limitations, the model captured rather well the dynamic of flow generation and was able to predict the range of nutrient concentrations in surface water. The contribution of urban areas to the polluting loads at catchment scale is relevant especially during the dry season.

Candela, Angela; Viviani, Gaspare

2010-05-01

292

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

293

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

294

Parsimonious Hydrologic and Nitrate Response Models For Silver Springs, Florida  

NASA Astrophysics Data System (ADS)

Silver Springs with an approximate discharge of 25 m3/sec is one of Florida's first magnitude springs and among the largest springs worldwide. Its 2500-km2 springshed overlies the mostly unconfined Upper Floridan Aquifer. The aquifer is approximately 100 m thick and predominantly consists of porous, fractured and cavernous limestone, which leads to excellent surface drainage properties (no major stream network other than Silver Springs run) and complex groundwater flow patterns through both rock matrix and fast conduits. Over the past few decades, discharge from Silver Springs has been observed to slowly but continuously decline, while nitrate concentrations in the spring water have enormously increased from a background level of 0.05 mg/l to over 1 mg/l. In combination with concurrent increases in algae growth and turbidity, for example, and despite an otherwise relatively stable water quality, this has given rise to concerns about the ecological equilibrium in and near the spring run as well as possible impacts on tourism. The purpose of the present work is to elaborate parsimonious lumped parameter models that may be used by resource managers for evaluating the springshed's hydrologic and nitrate transport responses. Instead of attempting to explicitly consider the complex hydrogeologic features of the aquifer in a typically numerical and / or stochastic approach, we use a transfer function approach wherein input signals (i.e., time series of groundwater recharge and nitrate loading) are transformed into output signals (i.e., time series of spring discharge and spring nitrate concentrations) by some linear and time-invariant law. The dynamic response types and parameters are inferred from comparing input and output time series in frequency domain (e.g., after Fourier transformation). Results are converted into impulse (or step) response functions, which describe at what time and to what magnitude a unitary change in input manifests at the output. For the hydrologic response model, frequency spectra of groundwater recharge and spring discharge suggest an exponential response model, which may explain a significant portion of spring discharge variability with only two fitting parameters (mean response time 2.4 years). For the transport model, direct use of nitrate data is confounded by inconsistent data and a strong trend. Instead, chloride concentrations in rainfall and at the spring are investigated as a surrogate candidate. Preliminary results indicate that the transport response function of the springshed as a whole may be of the gamma type, which possesses both a larger initial peak as well as a longer tail than the exponential response function. This is consistent with the large range of travel times to be expected between input directly into fast conduits connected to the spring (e.g., though sinkholes) and input or back-diffusion from the rock matrix. The result implies that reductions in nitrate input, especially at remote and hydraulically not well connected locations, will only manifest in a rather delayed and smoothed out form in concentration observed at the spring.

Klammler, Harald; Yaquian-Luna, Jose Antonio; Jawitz, James W.; Annable, Michael D.; Hatfield, Kirk

2014-05-01

295

Addressing the Challenges of Distributed Hydrologic Modeling for Operational Forecasting  

NASA Astrophysics Data System (ADS)

Operational forecasting systems must provide reliable, accurate and timely flood forecasts for a range of catchments from small rapidly responding mountain catchments and urban areas to large, complex but more slowly responding fluvial systems. Flood forecasting systems have evolved from simple forecasting for flood mitigation to real-time decision support systems for real-time reservoir operations for water supply, navigation, hydropower, for managing environmental flows and habitat protection, cooling water and water quality forecasting. These different requirements lead to a number of challenges in applying distributed modelling in an operational context. These challenges include, the often short time available for forecasting that requires a trade-off between model complexity and accuracy on the one hand and on the other hand the need for efficient calculations to reduce the computation times. Limitations in the data available in real-time require modelling tools that can not only operate on a minimum of data but also take advantage of new data sources such as weather radar, satellite remote sensing, wireless sensors etc. Finally, models must not only accurately predict flood peaks but also forecast low flows and surface water-groundwater interactions, water quality, water temperature, optimal reservoir levels, and inundated areas. This paper shows how these challenges are being addressed in a number of case studies. The central strategy has been to develop a flexible modelling framework that can be adapted to different data sources, different levels of complexity and spatial distribution and different modelling objectives. The resulting framework allows amongst other things, optimal use of grid-based precipitation fields from weather radar and numerical weather models, direct integration of satellite remote sensing, a unique capability to treat a range of new forecasting problems such as flooding conditioned by surface water-groundwater interactions. Results from flood modelling on the Odra River in Poland show that this model system can perform as well as traditional models and gives good predictions in mountainous catchments. By allowing different process representations to be applied within the same framework, it is possible to develop hydrological models in a phased manner. This phased approach was used for example in the Napa Valley, California where it is important to balance water demands for urban areas, agriculture, and ecosystem preservation while maintaining flood protection and water quality. A first regional model was developed with a detailed description of the surface process and a simple linear reservoir was used to simulate the groundwater component. Then a more detailed fully-distributed finite-difference groundwater model was constructed within the same framework while maintaining the surface water components. In the DMIP case study, Blue River, Oklahoma, this flexibility has been used to evaluate the performance of different model structures, and to determine the impact of grid resolution on model accuracy. The results show clear limits to the benefit attained by increasing model complexity and resolution. In contrast, detailed flood mapping using high resolution topography carried out with this tool in South Boulder Creek, Colorado show that very detailed description of the topography and flows paths are required for accurate flood mapping and determination of the flood risk. This framework is now being used to develop a flood forecasting system for the Big Cypress Basin in Florida.

Butts, M. B.; Yamagata, K.; Kobor, J.; Fontenot, E.

2008-05-01

296

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

Microsoft Academic Search

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

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

2008-01-01

297

Hydrologic Modeling on a 4km Grid over the Conterminous United States (CONUS)  

Microsoft Academic Search

The Hydrology Laboratory (HL) of the NOAA\\/National Weather Service's Office of Hydrologic Development (OHD) is developing advanced water resources products to meet the expanding demands of the public. Recently, the HL distributed modeling research program embarked on an exciting new development for large-scale, fine-resolution soil moisture modeling. We expect this work to provide important contributions to meet the Nation's need

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

2005-01-01

298

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

299

Coupling of a climate model and a hydrological model and implications on land surface fluxes  

NASA Astrophysics Data System (ADS)

In recent years there has been an increasing focus on the need to establish coupled climate-hydrological models to better describe the feedback processes in the energy and water fluxes between the atmosphere and the land surface. Such improved descriptions may be important for two main reasons. First, they may enable developments of improved climate models with more correct land surface feedbacks than the existing simple land surface schemes which have a poor representation of soil moisture and basically neglect the effects of groundwater. Secondly, they may be able to reduce the uncertainty in climate change impact predictions on water resources, which today are performed in an uncoupled two-step process, where output from a climate model is used to force a hydrological model. Within the HYACINTS project (www.hyacints.dk) we have by use of the Open Modelling Interface (OpenMI) standard developed a coupling between two model codes, the regional climate model HIRHAM and the hydrological model MIKE SHE. HIRHAM is a regional climate model (RCM) being used for dynamically downscaling of GCM results to a finer resolution (5-25 km). It is run on a high performance computer at the Danish Meteorological Institute using Linux. MIKE SHE is a distributed model with coupled descriptions of groundwater, unsaturated zone, overland flow, river flow and including a component for simulating energy and water fluxes between the land surface and the atmosphere. MIKE SHE is run on Windows PCs and typically operates on spatial grid scales between 25 m and 1 km depending on the modelling objectives. In contrary to other existing coupling approaches using the same model grid for the same domain in the climate and hydrological models, our coupling uses the large RCM domain with usual resolution and a hydrological model with a much finer resolution for a smaller domain. We show test results from a catchment in the US (225 km2 FIFE area) and a catchment inDenmark (2500 km2 Skjern River catchment) with focus on the effects on simulation of fluxes and the importance of groundwater. Furthermore, we discuss the potentials and limitations of coupled models at these scales.

Refsgaard, J.; Rasmussen, S.; Larsen, M. A.; Drews, M.; Butts, M. B.; Christensen, J. H.; Jensen, K. H.

2012-12-01

300

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

301

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

302

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

303

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

304

Stepwise calibration procedure for regional coupled hydrological-hydrogeological models  

NASA Astrophysics Data System (ADS)

Stream-aquifer interaction is a complex process depending on regional and local processes. Indeed, the groundwater component of hydrosystem and large scale heterogeneities control the regional flows towards the alluvial plains and the rivers. In second instance, the local distribution of the stream bed permeabilities controls the dynamics of stream-aquifer water fluxes within the alluvial plain, and therefore the near-river piezometric head distribution. In order to better understand the water circulation and pollutant transport in watersheds, the integration of these multi-dimensional processes in modelling platform has to be performed. Thus, the nested interfaces concept in continental hydrosystem modelling (where regional fluxes, simulated by large scale models, are imposed at local stream-aquifer interfaces) has been presented in Flipo et al (2014). This concept has been implemented in EauDyssée modelling platform for a large alluvial plain model (900km2) part of a 11000km2 multi-layer aquifer system, located in the Seine basin (France). The hydrosystem modelling platform is composed of four spatially distributed modules (Surface, Sub-surface, River and Groundwater), corresponding to four components of the terrestrial water cycle. Considering the large number of parameters to be inferred simultaneously, the calibration process of coupled models is highly computationally demanding and therefore hardly applicable to a real case study of 10000km2. In order to improve the efficiency of the calibration process, a stepwise calibration procedure is proposed. The stepwise methodology involves determining optimal parameters of all components of the coupled model, to provide a near optimum prior information for the global calibration. It starts with the surface component parameters calibration. The surface parameters are optimised based on the comparison between simulated and observed discharges (or filtered discharges) at various locations. Once the surface parameters have been determined, the groundwater component is calibrated. The calibration procedure is performed under steady state hypothesis (to minimize the procedure time length) using recharge rates given by the surface component calibration and imposed fluxes boundary conditions given by the regional model. The calibration is performed using pilot point where the prior variogram is calculated from observed transmissivities values. This procedure uses PEST (http//:www.pesthomepage.org/Home.php) as the inverse modelling tool and EauDyssée as the direct model. During the stepwise calibration process, each modules, even if they are actually dependant from each other, are run and calibrated independently, therefore contributions between each module have to be determined. For the surface module, groundwater and runoff contributions have been determined by hydrograph separation. Among the automated base-flow separation methods, the one-parameter Chapman filter (Chapman et al 1999) has been chosen. This filter is a decomposition of the actual base-flow between the previous base-flow and the discharge gradient weighted by functions of the recession coefficient. For the groundwater module, the recharge has been determined from surface and sub-surface module. References : Flipo, N., A. Mourhi, B. Labarthe, and S. Biancamaria (2014). Continental hydrosystem modelling : the concept of nested stream-aquifer interfaces. Hydrol. Earth Syst. Sci. Discuss. 11, 451-500. Chapman,TG. (1999). A comparison of algorithms for stream flow recession and base-flow separation. hydrological Processes 13, 701-714.

Labarthe, Baptiste; Abasq, Lena; de Fouquet, Chantal; Flipo, Nicolas

2014-05-01

305

Open Source assimilation tool for distributed hydrological model  

NASA Astrophysics Data System (ADS)

An advanced GIS data assimilation interface is a requisite to obtain a distributed hydrological model that is both transportable from catchment to catchment and is easily adaptable to data resolution. This tool is achieved for the cartographic data as well as the linked information data. In the case of the Multi-Hydro-Version2 model (A. Giangola-Murzyn et al. 2012), several types of information are distributed on a regular grid. The grid cell size has to be chosen by the user and each cell has to be filled up with information. In order to be the most realistic as possible, the Multi-Hydro model takes into account several data. For that, the assimilation tool (MH-AssimTool) has to be able to import all these different information. The needed flexibility of the studied area and grid size requires that the GIS interface must be easy to take in hand and also practical. The solution of a main window for the geographical visualisation and hierarchical menus coupled with checkboxes was chosen. For example, the geographical information, like the topography or the land use can be visualized in the main window. For the other data, like the soil conductivity, the geology or the initial moisture, the information is demanded through several pop-up windows. Once the needed information imported, MH-AssimTool prepares automatically the data. For the topography data conversion, if the resolution is too small, an interpolation is done during the processing. As a result, all the converted data is in a good resolution for the modelling. As Multi-Hydro, MH-AssimTool is open source. It's coded in Visual Basic language coupled with a GIS library. The interface is built in such a way then it can be used by a non specialist. We will illustrate the efficiency of the tool with some case studies of peri-urban catchments of widely different sizes and characteristics. We will also explain some parts of the coding of the interface.

Richard, Julien; Giangola-Murzyn, Agathe; Tchiguirinskaia, Ioulia; Schertzer, Daniel

2013-04-01

306

Multi-objective optimization of empirical hydrological model for streamflow prediction  

NASA Astrophysics Data System (ADS)

Traditional calibration of hydrological models is performed with a single objective function. Practical experience with the calibration of hydrologic models reveals that single objective functions are often inadequate to properly measure all of the characteristics of the hydrologic system. To circumvent this problem, in recent years, a lot of studies have looked into the automatic calibration of hydrological models with multi-objective functions. In this paper, the multi-objective evolution algorithm MODE-ACM is introduced to solve the multi-objective optimization of hydrologic models. Moreover, to improve the performance of the MODE-ACM, an Enhanced Pareto Multi-Objective Differential Evolution algorithm named EPMODE is proposed in this research. The efficacy of the MODE-ACM and EPMODE are compared with two state-of-the-art algorithms NSGA-II and SPEA2 on two case studies. Five test problems are used as the first case study to generate the true Pareto front. Then this approach is tested on a typical empirical hydrological model for monthly streamflow forecasting. The results of these case studies show that the EPMODE, as well as MODE-ACM, is effective in solving multi-objective problems and has great potential as an efficient and reliable algorithm for water resources applications.

Guo, Jun; Zhou, Jianzhong; Lu, Jiazheng; Zou, Qiang; Zhang, Huajie; Bi, Sheng

2014-04-01

307

Simulation of groundwater and surface water over the continental US using a hyperresolution, integrated hydrologic model  

NASA Astrophysics Data System (ADS)

Interactions between surface and groundwater systems are well-established theoretically and observationally. While numerical models that solve both surface and subsurface flow equations in a single framework (matrix) are increasingly being applied, computational limitations have restricted their use to local and regional studies. Regional or watershed, scale simulations have been effective tools in understanding hydrologic processes, however there are still many questions, such as the adaptation of water resources to anthropogenic stressors and climate variability, that need to be answered across large spatial extents at high resolution. In response to this "grand challenge" in hydrology, we present the results of a parallel, integrated hydrologic model simulating surface and subsurface flow at high spatial resolution (1 km) over much of continental North America (~ 6 300 000 or 6.3 million km2). These simulations provide predictions of hydrologic states and fluxes, namely water table depth and streamflow, at unprecedented scale and resolution. The physically-based modeling approach used here requires limited parameterizations and relies only on more fundamental inputs, such as topography, hydrogeologic properties and climate forcing. Results are compared to observations and provide mechanistic insight into hydrologic process interaction. This study demonstrates both the feasibility of continental scale integrated models and their utility for improving our understanding of large-scale hydrologic systems; the combination of high resolution and large spatial extent facilitates novel analysis of scaling relationships using model outputs.

Maxwell, R. M.; Condon, L. E.; Kollet, S. J.

2014-11-01

308

Modeling Root Water Uptake in Hydrological and Climate Models  

Microsoft Academic Search

From 30 September to 2 October 1999 a workshop was held in Gif-sur-Yvette, France, with the central objective to develop a research strategy for the next 3-5 years, aiming at a systematic description of root functioning, rooting depth, and root distribution for modeling root water uptake from local and regional to global scales. The goal was to link more closely

Reinder A. Feddes; Holger Hoff; Michael Bruen; Todd Dawson; Patricia de Rosnay; Paul Dirmeyer; Robert B. Jackson; Pavel Kabat; Axel Kleidon; Allan Lilly; Andrew J. Pitman

2001-01-01

309

Consistency between hydrological models and field observations: Linking processes at the hillslope scale to hydrological responses at the watershed scale  

USGS Publications Warehouse

The purpose of this paper is to identify simple connections between observations of hydrological processes at the hillslope scale and observations of the response of watersheds following rainfall, with a view to building a parsimonious model of catchment processes. The focus is on the well-studied Panola Mountain Research Watershed (PMRW), Georgia, USA. Recession analysis of discharge Q shows that while the relationship between dQ/dt and Q is approximately consistent with a linear reservoir for the hillslope, there is a deviation from linearity that becomes progressively larger with increasing spatial scale. To account for these scale differences conceptual models of streamflow recession are defined at both the hillslope scale and the watershed scale, and an assessment made as to whether models at the hillslope scale can be aggregated to be consistent with models at the watershed scale. Results from this study show that a model with parallel linear reservoirs provides the most plausible explanation (of those tested) for both the linear hillslope response to rainfall and non-linear recession behaviour observed at the watershed outlet. In this model each linear reservoir is associated with a landscape type. The parallel reservoir model is consistent with both geochemical analyses of hydrological flow paths and water balance estimates of bedrock recharge. Overall, this study demonstrates that standard approaches of using recession analysis to identify the functional form of storage-discharge relationships identify model structures that are inconsistent with field evidence, and that recession analysis at multiple spatial scales can provide useful insights into catchment behaviour. Copyright ?? 2008 John Wiley & Sons, Ltd.

Clark, M.P.; Rupp, D.E.; Woods, R.A.; Tromp-van, Meerveld, H. J.; Peters, N.E.; Freer, J.E.

2009-01-01

310

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

311

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

312

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

313

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

314

Flood forecasting with DDD-application of a parsimonious hydrological model in operational flood forecasting in Norway  

NASA Astrophysics Data System (ADS)

A new parameter-parsimonious rainfall-runoff model, DDD (Distance Distribution Dynamics) has been run operationally at the Norwegian Flood Forecasting Service for approximately a year. DDD has been calibrated for, altogether, 104 catchments throughout Norway, and provide runoff forecasts 8 days ahead on a daily temporal resolution driven by precipitation and temperature from the meteorological forecast models AROME (48 hrs) and EC (192 hrs). The current version of DDD differs from the standard model used for flood forecasting in Norway, the HBV model, in its description of the subsurface and runoff dynamics. In DDD, the capacity of the subsurface water reservoir M, is the only parameter to be calibrated whereas the runoff dynamics is completely parameterised from observed characteristics derived from GIS and runoff recession analysis. Water is conveyed through the soils to the river network by waves with celerities determined by the level of saturation in the catchment. The distributions of distances between points in the catchment to the nearest river reach and of the river network give, together with the celerities, distributions of travel times, and, consequently unit hydrographs. DDD has 6 parameters less to calibrate in the runoff module than the HBV model. Experiences using DDD show that especially the timing of flood peaks has improved considerably and in a comparison between DDD and HBV, when assessing timeseries of 64 years for 75 catchments, DDD had a higher hit rate and a lower false alarm rate than HBV. For flood peaks higher than the mean annual flood the median hit rate is 0.45 and 0.41 for the DDD and HBV models respectively. Corresponding number for the false alarm rate is 0.62 and 0.75 For floods over the five year return interval, the median hit rate is 0.29 and 0.28 for the DDD and HBV models, respectively with false alarm rates equal to 0.67 and 0.80. During 2014 the Norwegian flood forecasting service will run DDD operationally at a 3h temporal resolution. Running DDD at a 3h resolution will give a better prediction of flood peaks in small catchments, where the averaging over 24 hrs will lead to a underestimation of high events, and we can better describe the progress floods in larger catchments. Also, at a 3h temporal resolution we make better use of the meteorological forecasts that for long have been provided at a very detailed temporal resolution.

Skaugen, Thomas; Haddeland, Ingjerd

2014-05-01

315

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

316

Hydrologic Sensitivity to Climate Change of Precipitation Patterns via Integrated Modeling  

NASA Astrophysics Data System (ADS)

Understanding the impacts of climate change on water resources is critical to ecosystems and to human well being. Most previous work has involved coupling hydrologic models to global and regional climate models. While there is impressive agreement among climate models on temperature increase, unfortunately precipitation estimates present "wildly diverging pictures" [Schiermeier, Nature 2010]. In the IPCC AR4 WG1 SPM on page 16 one sees for most of the mid-latitudes that more than 1/3 of the models disagree with the majority on even the sign of any precipitation change and significant agreement of 90% is typically only found in the polar reaches [Oreskes, Philosophy of Science 2010]. Since precipitation is the primary driver of hydrology, therefore coupling of these climate models to hydrology can only yield projections that are highly uncertain. This work instead offers basic insight into the connections between all sorts of climate possibilities and hydrology. The observational climate inputs to GSFLOW basin models have been tweaked to compute the sensitivity of hydrological components to change in many climate variables. Impacts were evaluated from individual changes from a precipitation pattern such as total amounts, event intensities, event rates, durations, frequencies, and season lengths. By considering each precipitation pattern separately, we separate the confounding factors when all are changing at the same time and can then observe the impact of each factor by itself. Sensitivities have been computed for some 20 hydrologic flow components, such as runoff, infiltration, soil ET, interflow, recharge, baseflow, and streamflows. This hydrological system is highly non-linear and so a single set of computed hydrologic sensitivity values only describes the hydrologic partitioning for a single environmental condition. For a more complete picture, hydrological sensitivities have been computed over wide ranges of climate variables, such as a warmer to a colder environment and also a wetter to a drier environment. The trends of sensitivities over these multi-dimensional environmental ranges can provide fundamental insight to how the hydrologic system responds to extensive climate possibilities. Part of this work involves the establishment of metrics for the trends and certainty of each of these precipitation patterns. For example, a century of past precipitation records are analyzed to yield the long-term direction and magnitude of change of each precipitation pattern. Computation of the standard deviation and a correlation coefficient and comparison with values of other patterns gives indications of which patterns are most reliable.

Daniels, B. K.

2011-12-01

317

Hydrologic modelling for climate change impacts analysis of shifts in future hydrologic regimes: implications for stream temperature and salmon habitat  

NASA Astrophysics Data System (ADS)

The challenges faced by climate change impact analysts must be solved through interdisciplinary collaboration between research scientists, institutions and stakeholders. In particular, hydrologic modelers, climate scientists, biologists, ecologists, engineers and water resource managers must interact to pool expertise and provide tools to address the complex issues associated with future climate change. The current study examines the results of an application of the VIC macro-scale hydrologic model to predict future changes to soil moisture, snowpack, evapo-transpiration, and streamflow in the Fraser Basin of British Columbia - and then apply these results to stream temperature and fish habitat models to predict future impacts on freshwater ecosystems. The results of this work will be presented to fisheries managers to provide them with the information needed to develop adaptation strategies that will help mitigate the adverse effects of climate change. This presentation will focus on the hydrologic modelling results of a number of downscaled scenarios to examine the projected differences for the 2050s (2041 - 2070) as compared to the historical baseline (1961- 1990). By the 2050s, although the magnitude of change varies by GCM and emissions scenarios, overall precipitation and temperature is projected to increase, particularly in the winter, which leads to increased winter time runoff for many basins. However, this is combined with declines in snow water equivalent (SWE) for many sites, which coupled with lower early season soil moisture, leads to declines in summer runoff and baseflow. SWE increases in some basins under the cgcm3 A1B and echam5 A1B scenarios at high elevations. A similar result was found in this region with the Canadian Regional Climate Model (CRCM) 4, driven with run 4 of the CGCM3 under the A2 emissions scenario. Lack of water availability during the summer time periods appears to limit evaporation, causing declines in summer ET across most sites. Higher peak flows, a shift in the spring melt (earlier) and increased winter runoff are characteristics observed at many of the streamflow sites analysed. These results suggest that while an increase in winter rain events will cause higher peak flows, winter warming generally leads to lower snowpacks and soil moisture stores, leading to a decline in summer water availability in this region. Lessons learned from the applications of modelling data and results across different model frameworks and for different scales will be discussed.

Bennett, K. E.; Werner, A. T.; Schnorbus, M.; Salathé, E. P.; Nelitz, M.

2009-05-01

318

Develop hydrological relationships using a modeling approach in Mississippi delta  

Technology Transfer Automated Retrieval System (TEKTRAN)

Agriculture management practices such as tillage and crop rotations alter the hydrological budget of watersheds. Changes happen to surface runoff can be easily identify with the help of intensive USGS stream gage network, available in Mississippi, but changes to ground water table is less understood...

319

The ability of a GCM-forced hydrological model to reproduce global discharge variability  

Microsoft Academic Search

Data from General Circulation Models (GCMs)\\u000aare often used to investigate hydrological impacts of climate\\u000achange. However GCM data are known to have large biases,\\u000aespecially for precipitation. In this study the usefulness of\\u000aGCM data for hydrological studies, with focus on discharge\\u000avariability and extremes, was tested by using bias-corrected\\u000adaily climate data of the 20CM3 control experiment from

F. C. Sperna Weiland; L. P. H. van Beek; J. C. J. Kwadijk; M. F. P. Bierkens

2010-01-01

320

Evaluating Satellite Rainfall Products and Their Impacts in Hydrologic Model Simulations  

Microsoft Academic Search

High-resolution rainfall products across the globe are increasingly becoming available from space-based platforms. However, examples of the operational uses of these products are rare. In this study, we evaluate the accuracy of high-resolution satellite rainfall products by comparing them with high-quality and dense ground-based rainfall observations, and assess their hydrological impacts by comparing observed streamflows with hydrologic model simulations forced

D. A. Zeweldi; M. Gebremichael

2009-01-01

321

Modeling and Analysis of Global and Regional Climate Change in Relation to Atmospheric Hydrologic Processes  

NASA Technical Reports Server (NTRS)

This research was directed to the development and application of global isentropic modeling and analysis capabilities to describe hydrologic processes and energy exchange in the climate system, and discern regional climate change. An additional objective was to investigate the accuracy and theoretical limits of global climate predictability which are imposed by the inherent limitations of simulating trace constituent transport and the hydrologic processes of condensation, precipitation and cloud life cycles.

Johnson, Donald R.

2001-01-01

322

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

323

Coupling a distributed hydrological model with a vegetated slope stability model  

NASA Astrophysics Data System (ADS)

Vegetation significantly influences the hydrological and mechanical properties which are relevant for the stability of shallow soils along sloping surfaces. In view of the complexity of soil plant hydrological interactions, the quantification of root mechanical reinforcement remains a challenge. In this paper we couple root reinforcement models with a quasi-dynamic wetness index (QDI), which is specifically designed for estimating the local wetness conditions by accounting for the character of the upslope topography and the time of the lateral soil moisture distribution. The overall modelling strategy can be effectively employed for assessing the relative hazard of shallow landslides accounting for vegetation patterns and dominant forest management practices. The methodology is applied to an area located in Northern Tuscany to assess the effect of root degradation after tree logging on the spatial occurrence of shallow landslides during extreme rainfall events.

Preti, F.; Dani, A.; Chirico, G. B.

2012-04-01

324

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

325

A linked global model of terrestrial hydrologic processes: Simulation of modern rivers, lakes, and wetlands  

Microsoft Academic Search

A terrain-based hydrologic model is developed to simulate rivers, lakes, and wetlands on the continental scale as a linked dynamical system. This surface water area model (SWAM) is an extension of earlier work [Coe, 1997] and is based on a linear reservoir model. The model requires, as input, estimates of runoff, precipitation, and evaporation from either observations or climate simulations.

Michael T. Coe

1998-01-01

326

A linked global model of terrestrial hydrologic processes: Simulation of modern rivers, lakes, and wetlands  

Microsoft Academic Search

A terrain-based hydrologic model is developed to simulate rivers, lakes, and wetlands on the continental scale as a linked dynamical system. This surface water area model (SWAM) is an extension of earlier work (Coe, 1997) and is based on a linear reservoir model. The model re- quires, as input, estimates of runoff, precipitation, and evaporation from either observations or climate

Michael T. Coe

1998-01-01

327

Terrestrial vegetation and water balance—hydrological evaluation of a dynamic global vegetation model  

Microsoft Academic Search

Earth's vegetation plays a pivotal role in the global water balance. Hence, there is a need to model dynamic interactions and feedbacks between the terrestrial biosphere and the water cycle. Here, the hydrological performance of the Lund–Potsdam–Jena model (LPJ), a prominent dynamic global vegetation model, is evaluated. Models of this type simulate the coupled terrestrial carbon and water cycle, thus

Dieter Gerten; Sibyll Schaphoff; Uwe Haberlandt; Wolfgang Lucht; Stephen Sitch

2004-01-01

328

Application of Hierarchy Theory to Cross-Scale Hydrologic Modeling of Nutrient Loads  

EPA Science Inventory

We describe a model called Regional Hydrologic Modeling for Environmental Evaluation 16 (RHyME2) for quantifying annual nutrient loads in stream networks and watersheds. RHyME2 is 17 a cross-scale statistical and process-based water-quality model. The model ...

329

Toward improving the reliability of hydrologic prediction: Model structure uncertainty and its quantification using ensemble-based genetic programming framework  

Microsoft Academic Search

Uncertainty analysis is starting to be widely acknowledged as an integral part of hydrological modeling. The conventional treatment of uncertainty analysis in hydrologic modeling is to assume a deterministic model structure, and treat its associated parameters as imperfectly known, thereby neglecting the uncertainty associated with the model structure. In this paper, a modeling framework that can explicitly account for the

Kamban Parasuraman; Amin Elshorbagy

2008-01-01

330

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

331

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

332

An ensemble modeling framework for understanding differences in hydrological model performance across the contiguous US  

NASA Astrophysics Data System (ADS)

Given rapid increases in computing power, the field of "large sample hydrology" is becoming increasingly popular as a way to understand model shortcomings and improve model performance. This presentation summarizes (1) development of an ensemble Contiguous United States (CONUS), gridded, daily, station based historical precipitation and temperature dataset used to understand how uncertainty in precipitation and temperature affects regional variability in hydrological model performance; and (2) analysis of the performance of the Snow17-Sacramento model for 670 basins across the contiguous USA. This work allows for characterization of model strengths and weaknesses over a large number of basins, spanning a wide range of hydro-climatic conditions. Analysis of the ensemble forcing data in an uncertainty framework provides an improved understanding of how climate station density and the hydro-climatic regime affect the relative importance of input data uncertainties and model structural weaknesses. Results show that model Nash-Sutcliffe efficiency (NSE), a popular measure of hydrologic model performance, varies regionally over the CONUS with skill in 90% of basins ranging from 0.55 to 0.94. Poor model performance is found in arid and semi-arid regions (e.g. high Plains of the U.S). Physically-based diagnostic measures show that, for example, low flow periods are generally over-predicted in rain-dominated basins and under-predicted in arid regions and basins with large seasonal snowpack. Reasons for poor NSE in arid and semi-arid basins point to uncertainties in the model forcing data and possible relationships between basin flashiness and forcing uncertainties. Future work will include a quantitative total error analysis using the Bayesian Total Error Analysis (BATEA) methodology.

Newman, Andy; Clark, Martyn; Wood, Andy; Craig, Jason; Sampson, Kevin; Hay, Lauren; Bock, Andy; Brekke, Levi; Arnold, Jeff

2014-05-01

333

Assessing anthropogenic influence on the hydrology of small peri-urban catchments: Development of the object-oriented PUMMA model by integrating urban and rural hydrological models  

NASA Astrophysics Data System (ADS)

Distributed hydrological models are useful tools for process understanding and water management, especially in peri-urban catchments where the landscape heterogeneity is large, caused by a patchwork of natural and urbanized areas. This paper presents the Peri-Urban Model for landscape MAnagement (PUMMA) built within the LIQUID® modeling framework, specifically designed to study the hydrology of peri-urban catchments. It combines rural and urban hydrological models, and is used for process understanding. The originality of PUMMA is to follow a fully object-oriented approach, for both model mesh building and process representation. Urban areas, represented by cadastral units and rural areas divided in Hydrological Response Units are thus modeled with different interacting process modules. This provides a detailed representation of the runoff generation on natural and impervious areas. Furthermore, the exchange between process modules facilitates the simulation of subsurface and overland flow, as well as groundwater drainage by sewer pipes. Several drainage networks can coexist and interact (e.g. via storm water overflow devices) and water can be stored in retention basins, which allows the modeling of complex suburban drainage systems with multiple outlets. The model is then applied to the Chaudanne catchment (2.7 km2), located in the suburbs of Lyon, France. The uncalibrated model results show the importance of surface runoff from impervious areas for summer events and flow contributions from rural zones for winter events. Furthermore, the model reveals that the retention capacity of the Chaudanne catchment is larger than for classical urban catchments due to the peri-urban character of the catchment.

Jankowfsky, S.; Branger, F.; Braud, I.; Rodriguez, F.; Debionne, S.; Viallet, P.

2014-09-01

334

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

335

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

336

Lamivudine treatment for severe acute HBV hepatitis  

Microsoft Academic Search

Treatment for acute hepatitis B is recommended in order to reduce the risk of progression to fulminant hepatitis and the need of OLT. We report our experience on treatment with high dose lamivudine, in patients with severe acute HBV infection. The diagnosis was based on clinical and virological findings and exclusion of other known causes of liver damage. The decision

Andrea Lisotti; Francesco Azzaroli; Federica Buonfiglioli; Marco Montagnani; Flavio Alessandrelli; Giuseppe Mazzella

337

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

2011-12-01

338

A model of hydrological and mechanical feedbacks of preferential fissure flow in a slow-moving landslide  

NASA Astrophysics Data System (ADS)

The importance of hydrological processes for landslide activity is generally accepted. However, the relationship between precipitation, hydrological responses and movement is not straightforward. Groundwater recharge is mostly controlled by the hydrological material properties and the structure (e.g., layering, preferential flow paths such as fissures) of the unsaturated zone. In slow-moving landslides, differential displacements caused by the bedrock structure complicate the hydrological regime due to continuous opening and closing of the fissures, creating temporary preferential flow paths systems for infiltration and groundwater drainage. The consecutive opening and closing of fissure aperture control the formation of a critical pore water pressure by creating dynamic preferential flow paths for infiltration and groundwater drainage. This interaction may explain the seasonal nature of the slow-moving landslide activity, including the often observed shifts and delays in hydrological responses when compared to timing, intensity and duration of precipitation. The main objective of this study is to model the influence of fissures on the hydrological dynamics of slow-moving landslide and the dynamic feedbacks between fissures, hydrology and slope stability. For this we adapt the spatially distributed hydrological and slope stability model (STARWARS) to account for geotechnical and hydrological feedbacks, linking between hydrological response of the landside and the dynamics of the fissure network and applied the model to the hydrologically controlled Super-Sauze landslide (South French Alps).

Krzeminska, D. M.; Bogaard, T. A.; Malet, J.-P.; van Beek, L. P. H.

2013-03-01

339

A model of hydrological and mechanical feedbacks of preferential fissure flow in a slow-moving landslide  

NASA Astrophysics Data System (ADS)

The importance of hydrological processes for landslide activity is generally accepted. However, the relationship between precipitation, hydrological responses and movement is not straightforward. Groundwater recharge is mostly controlled by the hydrological material properties and the structure (e.g. layering, preferential flow paths such as fissures) of the unsaturated zone. In slow-moving landslides, differential displacements caused by the bedrock structure complicate the hydrological regime due to continuous opening and closing of the fissures, creating temporary preferential flow paths systems for infiltration and groundwater drainage. The consecutive opening and closing of fissure aperture control the formation of a critical pore water pressure by creating dynamic preferential flow paths for infiltration and groundwater drainage. This interaction may explain the seasonal nature of the slow-moving landslide activity, including the often observed shifts and delays in hydrological responses when compared to timing, intensity and duration of precipitation. The main objective of this study is to model the influence of fissures on the hydrological dynamics of slow-moving landslide and the dynamic feedbacks between fissures, hydrology and slope stability. For this we adapt the spatially distributed hydrological and slope stability model (STARWARS) to account for geotechnical and hydrological feedbacks, linking between hydrological response of the landside and the dynamics of the fissure network and applied the model to the hydrologically controlled Super-Sauze landslide (South French Alps).

Krzeminska, D. M.; Bogaard, T. A.; Malet, J.-P.; van Beek, L. P. H.

2012-10-01

340

Assessing impacts of hydropower schemes in upland rivers and sensitivity to hydrological change: new modelling tools for evaluating environmental flows  

NASA Astrophysics Data System (ADS)

Upland river systems provide a suite of critical ecosystem services, such as the provision of high quality downstream water supplies and the maintenance of in-stream habitats. Environmental legislation dictates that exploiting the hydro-power potential of such headwaters requires that the ecological status of in-stream habitats is maintained. This requires that decision makers have adequate scientific understanding of natural flow regimes, the nature of regulation impacts, and the sensitivity of managed systems to future change. This is often limited by a lack of adequate pre- regulation data. Here we present a new modelling tool that can be used in data sparse mountain river ecosystems to assess current impacts, evaluate sensitivity to future change and provide a basis for discussing the development of new adaptive management strategies. The HBV rainfall-runoff model was adapted to incorporate regulation components (reservoirs, water transfers), and applied to the heavily regulated River Lyon (391 km2), Scotland, UK. The Lyon has long been subjected to hydropower generation, which is supported by several river impoundments and a complex network of inter- and intra-catchment water transfers, and there are concerns that these are affecting high conservation status freshwater populations of Atlantic Salmon (Salmo salar). In the absence of adequate pre-regulation data, the model was used to characterise the natural flow regime, assess the regulation impacts, and explore sensitivities to hydrological changes in water management. Overall, changes following regulation in the Lyon include decreases in inter-and intra annual variability of all parameters of the flow regime in terms of magnitude, frequency, duration and timing that are important in various life stages of the Atlantic Salmon. Although these effects are most pronounced closest to the impoundments, the regulation affects the regime for a considerable distance downstream. Sensitivity tests showed that a more variable release regime, as opposed to changes in the efficiency of the present regulation regime, could be most beneficial for the ecological status of the Lyon. The simple, conceptual modelling approach presented here captures the dominant catchment and regulation processes well, especially at the time scale at which operation rules apply. Consequentially, it is data undemanding, flexible, widely applicable, and its results are easily communicated to stakeholders. Hence, it is providing a basis for assessing impacts on flow regimes and informing environmental flows in other (data sparse) regions with heavily regulated mountain river ecosystems.

Tetzlaff, D.; Geris, J.; Seibert, J.; Vis, M.; Soulsby, C.

2013-12-01

341

Application of a Conceptual Hydrologic Model in Teaching Hydrologic Processes  

E-print Network

a conceptual rainfall-runoff model, Doctoral Dissertation,models that are based on analyzing observed input (e.g. rainfall) andmodel includes a module that processes the input precipitation either as rainfall

Aghakouchak, Amir; Habib, Emad

2010-01-01

342

Disaggregation of spatial rainfall fields for hydroloigcal modelling Hydrology and Earth System Sciences, 5(2), 165173 (2001) EGS  

E-print Network

Disaggregation of spatial rainfall fields for hydroloigcal modelling 165 Hydrology and Earth System Sciences, 5(2), 165­173 (2001) © EGS Disaggregation of spatial rainfall fields for hydrological modelling N for the downscaling of meteorological model outputs. Keywords: Rainfall, disaggregation, General Circulation Model

Boyer, Edmond

2001-01-01

343

Development and comparison in uncertainty assessment based Bayesian modularization method in hydrological modeling  

NASA Astrophysics Data System (ADS)

SummaryWith respect to model calibration, parameter estimation and analysis of uncertainty sources, various regression and probabilistic approaches are used in hydrological modeling. A family of Bayesian methods, which incorporates different sources of information into a single analysis through Bayes' theorem, is widely used for uncertainty assessment. However, none of these approaches can well treat the impact of high flows in hydrological modeling. This study proposes a Bayesian modularization uncertainty assessment approach in which the highest streamflow observations are treated as suspect information that should not influence the inference of the main bulk of the model parameters. This study includes a comprehensive comparison and evaluation of uncertainty assessments by our new Bayesian modularization method and standard Bayesian methods using the Metropolis-Hastings (MH) algorithm with the daily hydrological model WASMOD. Three likelihood functions were used in combination with standard Bayesian method: the AR(1) plus Normal model independent of time (Model 1), the AR(1) plus Normal model dependent on time (Model 2) and the AR(1) plus Multi-normal model (Model 3). The results reveal that the Bayesian modularization method provides the most accurate streamflow estimates measured by the Nash-Sutcliffe efficiency and provide the best in uncertainty estimates for low, medium and entire flows compared to standard Bayesian methods. The study thus provides a new approach for reducing the impact of high flows on the discharge uncertainty assessment of hydrological models via Bayesian method.

Li, Lu; Xu, Chong-Yu; Engeland, Kolbjørn

2013-04-01

344

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

345

Developments on informal approaches to multi-criteria calibration and uncertainty analysis of hydrologic models  

NASA Astrophysics Data System (ADS)

Uncertainty analysis is known as a crucially important step in the calibration phase of hydrologic models. A variety of techniques have been suggested to quantify uncertainties in hydrological modeling ranging from simple Monte Carlo approaches to more complex Bayesian methods. Despite the robust theoretical underpinnings of the latter, since complex hydrological modeling experiments might challenge the statistical assumptions involved, a variety of informal methods have been alternatively proposed for calibration and uncertainty analysis studies. These methods have been shown to be simple, practical, and usually perform well (in comparison with formal techniques) in terms of providing general insights into prediction uncertainty. Our study provides new developments on sampling-based informal methods for multi-criteria calibration and uncertainty analysis of hydrologic models. It first provides a formalized framework for comparison among multi-criteria calibration and uncertainty analysis methods and applies it to evaluate a number of recently developed methods in the literature. Moreover, the study develops a new informal multi-criteria uncertainty analysis approach through Markov Chain Monte Carlo (MCMC) sampling. Instead of aggregating the criteria (as the commonly used approach in the literature), the proposed method utilizes the concept of Pareto dominance within MCMC sampling to explicitly account for different criteria. The preliminary results demonstrate that the comparison framework is very practical. Furthermore, in terms of the predictive capability of hydrologic models, the Pareto-based MCMC sampling performs better than the aggregation-based approach.

Shafii Hassanabadi, M.; Tolson, B.; Matott, L. S.

2013-12-01

346

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

347

Using the cloud to speed-up calibration of watershed-scale hydrologic models (Invited)  

NASA Astrophysics Data System (ADS)

This research focuses on using the cloud to address computational challenges associated with hydrologic modeling. One example is calibration of a watershed-scale hydrologic model, which can take days of execution time on typical computers. While parallel algorithms for model calibration exist and some researchers have used multi-core computers or clusters to run these algorithms, these solutions do not fully address the challenge because (i) calibration can still be too time consuming even on multicore personal computers and (ii) few in the community have the time and expertise needed to manage a compute cluster. Given this, another option for addressing this challenge that we are exploring through this work is the use of the cloud for speeding-up calibration of watershed-scale hydrologic models. The cloud used in this capacity provides a means for renting a specific number and type of machines for only the time needed to perform a calibration model run. The cloud allows one to precisely balance the duration of the calibration with the financial costs so that, if the budget allows, the calibration can be performed more quickly by renting more machines. Focusing specifically on the SWAT hydrologic model and a parallel version of the DDS calibration algorithm, we show significant speed-up time across a range of watershed sizes using up to 256 cores to perform a model calibration. The tool provides a simple web-based user interface and the ability to monitor the calibration job submission process during the calibration process. Finally this talk concludes with initial work to leverage the cloud for other tasks associated with hydrologic modeling including tasks related to preparing inputs for constructing place-based hydrologic models.

Goodall, J. L.; Ercan, M. B.; Castronova, A. M.; Humphrey, M.; Beekwilder, N.; Steele, J.; Kim, I.

2013-12-01

348

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

349

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

350

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

351

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

352

Assessment of NASA's Physiographic and Meteorological Datasets as Input to HSPF and SWAT Hydrological Models  

NASA Technical Reports Server (NTRS)

This paper documents the use of simulated Moderate Resolution Imaging Spectroradiometer land use/land cover (MODIS-LULC), NASA-LIS generated precipitation and evapo-transpiration (ET), and Shuttle Radar Topography Mission (SRTM) datasets (in conjunction with standard land use, topographical and meteorological datasets) as input to hydrological models routinely used by the watershed hydrology modeling community. The study is focused in coastal watersheds in the Mississippi Gulf Coast although one of the test cases focuses in an inland watershed located in northeastern State of Mississippi, USA. The decision support tools (DSTs) into which the NASA datasets were assimilated were the Soil Water & Assessment Tool (SWAT) and the Hydrological Simulation Program FORTRAN (HSPF). These DSTs are endorsed by several US government agencies (EPA, FEMA, USGS) for water resources management strategies. These models use physiographic and meteorological data extensively. Precipitation gages and USGS gage stations in the region were used to calibrate several HSPF and SWAT model applications. Land use and topographical datasets were swapped to assess model output sensitivities. NASA-LIS meteorological data were introduced in the calibrated model applications for simulation of watershed hydrology for a time period in which no weather data were available (1997-2006). The performance of the NASA datasets in the context of hydrological modeling was assessed through comparison of measured and model-simulated hydrographs. Overall, NASA datasets were as useful as standard land use, topographical , and meteorological datasets. Moreover, NASA datasets were used for performing analyses that the standard datasets could not made possible, e.g., introduction of land use dynamics into hydrological simulations

Alacron, Vladimir J.; Nigro, Joseph D.; McAnally, William H.; OHara, Charles G.; Engman, Edwin Ted; Toll, David

2011-01-01

353

Risk stratification of HBV infection in Asia-Pacific region.  

PubMed

Hepatitis B virus (HBV) infection is the major etiology of chronic liver disease worldwide and thus a global health problem, especially in Asia-Pacific region. The long-term outcomes of Asian HBV carriers vary widely; however, a significant proportion of them will finally develop end-stage liver disease. Over the past decade, several host and HBV factors predictive of clinical outcomes in Asian HBV carriers have been identified. The community-based REVEAL-HBV study illustrated the strong association between HBV-DNA level at study entry and risk of HCC over time, and male gender, older age, high serum alanine aminotransferase (ALT) level, positive HBeAg, higher HBV-DNA level, HBV genotype C infection and core promoter mutation are independently associated with a higher hepatocellular carcinoma (HCC) risk. Another hospital-based ERADICATE-B cohort further validated the HCC risk started to increase when HBV-DNA level was higher than 2,000 IU/mL. Of particular note, in patients with low viral load (HBV-DNA level <2,000 IU/mL), HBsAg level ?1,000 IU/mL was a new independent risk factor for HCC. With the results from REVEAL-HBV study, a risk calculator for predicting HCC in adult non-cirrhotic patients has been developed and validated by independent international cohorts (REACH-B). With the combination of HBV-DNA, HBsAg, and ALT levels, ERADICATE-B study proposed an algorithm to predict disease progression and categorize risk levels of HCC as well as corresponding management in Asian HBV carriers. The introduction of transient elastography may further enhance the predictive power. In conclusion, HBsAg level can complement HBV-DNA level for the risk stratification of disease progression in Asian adult patients with chronic HBV infection. PMID:25320724

Kao, Jia-Horng

2014-09-01

354

Steroid-free chemotherapy decreases risk of hepatitis B virus (HBV) reactivation in HBV-carriers with lymphoma  

Microsoft Academic Search

Reactivation of hepatitis is one of the most serious complications of chemotherapy in lymphoma patients who are carriers of the hepatitis B virus (HBV). Glucocorticoids are linked to increased risk of HBV reactivation. This study seeks to clarify whether removal of glucocorticoids from chemotherapy regimens may decrease the risk of HBV reactivation. Eligible patients were seropositive for hepatitis B surface

Ann-Lii Cheng; Chao A. Hsiung; Ih-Jen Su; Ming-Chih Chang; Chao-Jung Tsao; Woei-Yao Kao; Wu-Ching Uen; Chih-Hung Hsu; Hwei-Fan Tien; Tsu-Yi Chao; Li-Tzong Chen; Jacqueline Whang-Peng

2003-01-01

355

Are Hydrologic Model Parameters Scalable? An Investigation into the Catchment Connectivity Model  

NASA Astrophysics Data System (ADS)

Rainfall-runoff models are often able to match streamflow dynamics (following calibration), while at the same time failing to produce simulations that are consistent with internal watershed processes. This well-recognized fact led to the development of the recently introduced Catchment Connectivity Model (CCM). Developed following a dominant process conceptualization based on hillslope hydrologic connectivity at the Tenderfoot Creek Experimental Forest (TCEF; Montana, USA), the three-parameter CCM is a spatially explicit model structure. The CCM has been validated against extensive field observations of hillslope hydrologic connectivity (an internal process simulated by the model) to demonstrate its internal consistency, in addition to a traditional