Hydrological Simulation Program Research Articles

Estimation of dynamic load of mercury in a river with BASINS-HSPF model

Purpose Mercury (Hg) is a naturally occurring element and a pervasive toxic pollutant. This study investigated the dynamic loads of Hg from the Cedar–Ortega Rivers watershed into the Lower St. Johns River (LSJR), Florida, USA, using the better assessment science integrating point and nonpoint sources (BASINS)-hydrologic simulation program—FORTRAN (HSPF) model.

Mass Balance and Water Quality Modeling for Load Allocation of Escherichia coli in an Urban Watershed

A modeling approach based on mass balance coupled with the Hydrologic Simulation Program in FORTRAN (HSPF) is developed in this study to evaluate bacteria reduction strategies and their impact on water quality for an urban watershed in Texas. This approach allowed for spatial and temporal representation of bacteria loading from the adjacent watershed that was balanced with in-stream loading. This decreased the uncertainty in source loading estimates and reduced the number of variables requiring calibration. The resulting model is used to investigate whether reduction goals calculated by using the mass balance data alone would actually achieve water quality standards. Results indicate that 100% elimination of runoff loads would be required to achieve the applicable standards, which is a somewhat unrealistic and costly endeavor. The utility of the developed model is further demonstrated by investigating spatial reduction strategies targeting the various bacteria sources in the watershed. Results indicate th...

Predicting plausible impacts of sets of climate and land use change scenarios on water resources

Our world is changing at an unprecedented rate in terms of climate and land use, but these changes can affect our water resources. Hence, we need a methodology that can predict both their individual and agglomerative ramifications. Using the Little Miami River (LMR) watershed as a case study, this paper describes a spatial analytical approach integrating mathematical modeling and geographical information sciences to quantitatively examine the relative importance of the separate and combined hydrologic and water quality impacts of climate and land use changes. The Hydrologic Simulation Program – Fortran (HSPF) model was chosen in this study to simulate stream flow and nutrient transport process. Five hypothetical climate change scenarios were used to cover the possible ranges of variability in the year 2050. An enhanced population-coupled Markov-Cellular Automata (CA-Markov) land use model was developed to predict the 2050 land use pattern. When these scenarios were incorporated into the HSPF model, the future conditions in the LMR basin were postulated. The findings demonstrated that: 1) the LMR watershed would experience an increase in flow and nutrients under the 2050 land use projection, 2) stream flow and water quality impacts would be amplified when both climate and land use changes were simultaneously considered, 3) land use change (and in the case of the LMR watershed, urbanization) could help to alleviate water shortage during the dry years, 4) total phosphorus and nitrogen would increase under all future climate and land use scenarios; the highest increase was found under the combined wettest and future land use scenarios, and 5) the described approach is effective in simulating the hydrologic and water quality effects of climate and land use changes in a basin scale. These results are relevant to planners; they can be useful in formulating realistic watershed management policies and mitigation measures.

Integrating hydrologic modeling and land use projections for evaluation of hydrologic response and regional water supply impacts in semi-arid environments

Semi-arid environments are generally more sensitive to urbanization than humid regions in terms of both hydrologic modifications and water resources sustainability. The current study integrates hydrologic modeling and land use projections to predict long-term impacts of urbanization on hydrologic behavior and water supply in semi-arid regions. The study focuses on the Upper Santa Clara River basin in northern Los Angeles County, CA, USA, which is undergoing rapid and extensive development. The semi-distributed Hydrologic Simulation Program Fortran (HSPF) model is parameterized with land use, soil, and channel characteristics of the study watershed. Model parameters related to hydrologic processes are calibrated at the daily time step using various spatial configurations of precipitation and parameters. Potential urbanization scenarios are generated on the basis of a regional development plan. The calibrated (and validated) model is run under the proposed development scenarios for a 10 year period. Results reveal that increasing development increases total annual runoff and wet season flows, while decreases are observed in existing baseflow and groundwater recharge during both dry and wet seasons. As development increases, medium-sized storms increase in both peak flow and overall volume, while low and high flow events (extremes) appear less affected. Urbanization is also shown to decrease natural recharge and, when considered at the regional scale, may result in a loss of critical water supply to Southern California. The current study provides a coupled framework for a decision support tool that can guide efforts involved in regional urban development planning and water supply management.

Effect of Temporal and Spatial Rainfall Resolution on HSPF Predictive Performance and Parameter Estimation

Watershed-scale rainfall-runoff models are used for environmental management and regulatory modeling applications, but their effectiveness is limited by predictive uncertainties associated with model input data. This study evaluated the effect of temporal and spatial rainfall resolution on the predictive performance of Hydrological Simulation Program—Fortran (HSPF) using manual and automatic calibration procedures. Furthermore, the effect of automatic parameter estimation on the physical significance of calibrated parameter values was evaluated. Temporal resolutions examined included 15 min, 30 min, 1 h, and 2 h, and spatial resolution effects evaluated included the effect of a spatially averaged network of four rain gauges and Next-Generation Radar (NEXRAD) for selected rain events. Model efficiencies ranged from 0.31 to 0.86 when individual rain gauges (RG71, RG73, RG74, and RG77) were used one at a time. Model efficiency improved and ranged from 0.86 to 0.94 when a spatially averaged network of four ra...

The relative impacts of climate change and urbanization on the hydrological response of a Korean urban watershed

AbstractWe assessed the relative hydrological impacts of climate change and urbanization using an integrated approach that links the statistical downscaling model (SDSM), the Hydrological Simulation Program—Fortran (HSPF) and the impervious cover model (ICM). A case study of the Anyangcheon watershed, a representative urban region in Korea, illustrates how the proposed framework can be used to analyse the impacts of climate change and urbanization on water quantity and quality. The evaluation criteria were measurements of low flow (99, 95, and 90 percentile flow), high flow (10, 5, and 1 percentile value), pollutant concentration (30, 10, and 1 percentile value), and the numbers of days required to satisfy the target water quantity and quality for a sensitive comparison of subtle impacts of variations in these measures. Nine scenarios, including three climate scenarios (present conditions, A1B, and A2) and three land use change scenarios, were analysed using the HSPF model. The impacts of climate change on low flow (34·1–59·8% increase) and high flow (29·1–37·1% increase) were found to be much greater than those on the biochemical oxygen demand (BOD) (3·8–10·0% decrease). On the other hand, the impacts of urbanization on water quality (19·0–44·6% increase) are more significant than those on high (1·0–4·4% increase) and low flow (11·4–25·6% decrease). Furthermore, low flows are more sensitive to urbanization than high flows. The number of days required to satisfy the target water quantity and quality can be a sensitive criterion to compare the subtle impacts of climate and urbanization on human society, especially as they are much more sensitive than low flow and pollutant concentration. Finally, urbanization has a potent impact on BOD while climate change has a high impact on flow rate. Therefore, the impacts of both climate change and urbanization must be included in watershed management and water resources planning for sustainable development. Copyright © 2010 John Wiley & Sons, Ltd.

Estimating Water Budgets and Vertical Leakages for Karst Lakes in North-Central Florida (United States) Via Hydrological Modeling1

Lin, Zhulu, 2011. Estimating Water Budgets and Vertical Leakages for Karst Lakes in North-Central Florida (United States) Via Hydrological Modeling. Journal of the American Water Resources Association (JAWRA) 1-16. DOI: 10.1111/j.1752-1688.2010.00513.x Abstract: Newnans, Lochloosa, and Orange Lakes are closely hydrologically connected karst lakes located in north-central Florida, United States. The complex karst hydrology in this region poses a great challenge to the hydrological modeling that is essential to the development of Total Maximum Daily Loads for these lakes. We used a Hydrological Simulation Program – Fortran model coupled with the parallel Parameter ESTimation model calibration and uncertainty analysis software to estimate effectively the hydrological interactions between the lakes and the underlying upper Floridan aquifer and the water budgets for these three lakes. The net results of the lake-groundwater interactions in Newnans and Orange Lakes are that both lakes recharge the underlying upper Floridan aquifer, with the recharge rate of the latter one magnitude greater than that of the former. However, for Lochloosa Lake, the net lake-groundwater interaction is that the lake gains water from groundwater in a significant amount, approximately 40% of its total terrestrial water input. The annual average vertical leakages estimated for Newnans, Lochloosa, and Orange Lakes are 6.0 × 106, −8.9 × 106, and 44.4 × 106 m3, respectively. The average vertical hydraulic conductance (Kv/b) of the units between a lake bottom and the underlying upper Floridan aquifer in this region are also estimated to be from 1.26 × 10−4 to 1.01 × 10−3 day−1.

Analysis of Hydrological Processes Applying the HSPF Model in Selected Watersheds in Alabama, Mississippi, and Puerto Rico

The goal of this study was to evaluate the Hydrological Simulation Program FORTRAN (HSPF) to gain more insight in the underlying causes and mechanisms of hydrological processes in an upland basin in Alabama and Mississippi (1,856-km2 Luxapallila Creek), a humid subtropical watershed in coastal Alabama (140-km2 Fish River), and a steep-slope tropical catchment in Puerto Rico (99-km2 Rio Caonillas). For each watershed model, rainfall, potential evapotranspiration, and streamflow time series from January 1999 to December 2000 were used to calibrate model parameters and 2001 time series were applied to verify model results. In each study area, actual evapotranspiration was the main mechanism of water loss followed by river discharge. Annual baseflow values ranged from 58% of total discharge in Luxapallila Creek basin to 84% of total discharge in Fish River watershed. In Luxapallila Creek and Fish River, interflow was the primary mechanism of direct runoff; however, surface runoff was the main process of direct runoff in Rio Caonillas. The HSPF model was successfully adapted to model daily streamflow processes in Luxapallila Creek basin and Rio Caonillas catchment with coefficient of determination and Nash and Sutcliffe coefficient values between 0.61 and 0.71 for the entire period; however, the Fish River watershed model performance was poor. The poor performance is likely due to the lack of rainfall time series available within the watershed boundaries. In general, this study showed the robustness of the HSPF model in extreme environments (small catchments vs. large basins, flat vs. hilly areas, low vs. moderate/high runoff potential, tropical marine vs. humid subtropical climates).

Modeling Escherichia Coli and Its Sources in an Urban Bayou with Hydrologic Simulation Program—FORTRAN

Bacterial levels in Buffalo Bayou in Houston commonly exceed contact recreation standards. Potential sources of bacteria include wastewater treatment plants, sanitary sewer overflows, septic systems, wet and dry nonpoint-source discharges via direct runoff and pipes, direct deposition, and sediment. A water-quality model in the Hydrologic Simulation Program—FORTRAN (HSPF) was calibrated and validated for hydrology, sediment, and Escherichia coli and subsequently used to evaluate the impacts of the bacterial sources in the watershed. In addition, simple estimates of bacterial loads were calculated along with source evaluations from load duration curves. Load reductions based upon the simple estimates indicated that water-quality standards were met by reducing dry-weather indicator bacterial loads by 69% and wet-weather loads by 98%. When these load reductions were implemented in the HSPF model, however, standards were not met under dry-weather conditions. Residual nonpoint-source loading was found to cause the discrepancy between simple load estimate calculations and the developed water-quality model. This paper demonstrates that runoff can play a significant role in maintaining high levels of bacteria under all flow conditions and that understanding the temporal variations in bacterial source loading is critical to ensure that load reductions will achieve water-quality standards.

Modeling of Nitrogen Retention in Amite River

This paper presents an efficient and effective modeling approach to estimation of nitrogen retention in streams and rivers. The approach involves an extension of a newly developed longitudinal solute transport model, variable residence time (VART), by incorporating a first-order nitrogen reaction term. Parameters involved in the VART model are estimated using monthly mean flow and water quality data obtained through both field measurements and watershed modeling using the Hydrologic Simulation Program Fortran model. It is found that there is a strong correlation between nitrate-nitrogen removal rate and water temperature. In addition, low nitrate-nitrogen concentrations commonly occur when total organic carbon (TOC) and dissolved oxygen (DO) are also low, and high nitrogen concentrations correspond to high DO and TOC, indicating that denitrification is the primary biogeochemical process controlling nitrogen removal in natural rivers. The new approach is demonstrated through the computation of nitrogen removal in the Amite River, LA, USA. Functional relationships between the nitrate-nitrogen removal rate and water temperature are established for the Amite River. Monthly mean nitrate-nitrogen concentrations along the river are computed using the extended VART model, and computed nitrogen concentrations fit observed ones very well. The estimated annual nitrate-nitrogen removal in the Amite River is 27.4 tons or 15.5% of total nitrate-nitrogen transported annually through the Amite River.

Applications of simulation technique on debris-flow hazard zone delineation: a case study in Hualien County, Taiwan

Abstract. Debris flows pose severe hazards to communities in mountainous areas, often resulting in the loss of life and property. Helping debris-flow-prone communities delineate potential hazard zones provides local authorities with useful information for developing emergency plans and disaster management policies. In 2003, the Soil and Water Conservation Bureau of Taiwan proposed an empirical model to delineate hazard zones for all creeks (1420 in total) with potential of debris flows and utilized the model to help establish a hazard prevention system. However, the model does not fully consider hydrologic and physiographical conditions for a given creek in simulation. The objective of this study is to propose new approaches that can improve hazard zone delineation accuracy and simulate hazard zones in response to different rainfall intensity. In this study, a two-dimensional commercial model FLO-2D, physically based and taking into account the momentum and energy conservation of flow, was used to simulate debris-flow inundated areas. Sensitivity analysis with the model was conducted to determine the main influence parameters which affect debris flow simulation. Results indicate that the roughness coefficient, yield stress and volumetric sediment concentration dominate the computed results. To improve accuracy of the model, the study examined the performance of the rainfall-runoff model of FLO-2D as compared with that of the HSPF (Hydrological Simulation Program Fortran) model, and then the proper values of the significant parameters were evaluated through the calibration process. Results reveal that the HSPF model has a better performance than the FLO-2D model at peak flow and flow recession period, and the volumetric sediment concentration and yield stress can be estimated by the channel slope. The validation of the model for simulating debris-flow hazard zones has been confirmed by a comparison of field evidence from historical debris-flow disaster data. The model can successfully replicate the influence zone of the debris-flow disaster event with an acceptable error and demonstrate a better result than the empirical model adopted by the Soil and Water Conservation Bureau of Taiwan.

Fecal coliform modeling under two flow scenarios in St. Louis Bay of Mississippi

St. Louis Bay, along with its two major tributaries, Wolf River and Jourdan River, are included in the Mississippi 1998 Section 303(d) List for violation of the designated water use of recreation and shellfish harvesting. Fecal coliform was identified as one of the pollutants that caused the water quality impairment. In order to facilitate the total maximum daily loads (TMDL) development, the fecal coliform dynamics was investigated under 2 flow scenarios with a calibrated and validated modeling framework by integration of Environmental Fluid Dynamic Code (EFDC) and Hydrological Simulation Program Fortran (HSPF). EFDC was used to model the hydrodymics and fecal coliform transportation in the Bay and the tributaries, whereas HSPF was applied to compute the flow and fecal coliform loadings from the watersheds. The total amount of precipitation in the dry year simulation corresponds to a 50-year return period of low flow condition, and a 10-year return period of high flow condition for wet weather simulation. For EFDC modeling, the fecal coliform sources considered were the contributions from the 2 upper watersheds (no tidal influence), the 28 small surrounding watershed, and 12 municipal, industrial, and domestic point sources. When simulating the fecal coliform loadings from the 2 upper watersheds using HSPF, the simulated non-point source loadings of fecal coliform included wildlife, land application of hog and cattle manure, land application of poultry litter, and grazing animals. The EFDC modeling results indicated that the wet weather exerted greater stress on fecal coliform water quality conditions. The number of exceedance of fecal coliform water quality standard in wet year simulation is much higher than that in dry year simulation. The impact of the upper rural watersheds loads on fecal coliform levels in the St. Louis Bay is much less significant than that from the surrounding urban runoff. Fecal coliform TMDL development should be based on high flow conditions since the decision makers are more concerned about worse scenarios. This fecal coliform modeling research would provide useful information of critical condition selection for TMDLs development in similar coastal areas.

Improving HSPF Modeling Accuracy from FTABLES: Case Study for the Illinois River Basin

An application of the Hydrologic Simulation Program–FORTRAN (HSPF) model was developed for the entire Illinois River basin. During the simulation period from 1985 to 1995, simulated monthly and annual flows correlated well with observed data. However, its performance for daily flows in the lower portion of the basin was not satisfactory because of the complicated hydraulic condition of the Illinois River. In order to compensate the weakness of HSPF for flow routing, we have coupled a calibrated hydraulic model, one-dimensional unsteady flow through a full network of open channels (UNET), to improve flow routing accuracy and the overall performance of the HSPF model. In this study we intended to test how HSPF modeling accuracy can be improved from modifying function tables (FTABLES). We proposed four alternative sets of FTABLES: three (Sets B, C, and D) were based on Manning’s equation and one (Set E) used the flow-stage relationship. Simulations from these four alternatives were compared to the default FTABLES (Set A) and the coupled HSPF-UNET model. A comparison showed that improving the estimation on hydraulic gradients from flood frequency analysis (Set B) or improving the computation of reach geometry from surveyed cross sections (Set C) could only improve model accuracy. However, much better modeling accuracy can be obtained by improving both reach geometry and hydraulic gradients (Set D). Using the stage-discharge relationships simulated from a hydraulic model (Set E) also provided better results. The proposed methods have been successfully applied to watershed modeling with HSPF in the Illinois River basin. This study demonstrated that better HSPF modeling accuracy can be achieved with minimum effort from representative channel geometries and hydraulic gradients.

Latis: A Spatial Decision Support System to Assess Low-Impact Site Development Strategies

Significant advances have been made in the use of spatial and hydrologic models to quantify the impact of Best Management Practices (BMPs) and Low-Impact Development (LID) practices on water quality. Further advances are the goal of this work to add selection of BMP/LID and calculation of implementation costs, all integrated into a spatial decision support system (DSS). The Hydrologic Simulation Program in FORTRAN (HSPF), an unsteady flow model, was combined with links to desktop spatial data analysis tools, a spreadsheet listing BMP/LID and their implementation, operation, and maintenance cost data. Testing of the DSS, named Latis, allowed improvements in direct design of BMP, and a survey of landscape and engineering practitioners provided the impetus for a simplified version, Latis-LIDIA.

Autocalibration of HSPF for Simulation of Streamflow Using a Genetic Algorithm

Hydrologic models are essential to watershed planning and management, particularly in the San Antonio River watershed where competition for scarce water resources is a challenge. As a result, the calibration and validation of hydrologic models are essential steps for their successful application. In this study, we examined the use of a loosely coupled genetic algorithm (GA) as an autocalibration tool for optimization of model parameters for the Hydrologic Simulation Program - Fortran (HSPF), a model frequently used in surface hydrology and water quality modeling. The GA-HSPF model is a more objective and less time-consuming alternative to traditional trial-and-error methods. The objective function was optimized by minimizing the mean absolute error (MAE) between corresponding simulated and observed average daily streamflow in the San Antonio River watershed. The MAE was used to evaluate the fitness of the parameter set in the GA. The calibrated model parameters (LZSN, INFILT, AGWRC, UZSN, DEEPFR, LZETP, and INTFW) were selected based on a sensitivity analysis from a previous study. Goodness-of-fit of the GA calibrated model was evaluated using the Nash-Sutcliffe coefficient of efficiency, MAE, root mean square error, flow duration curves, wavelet analysis, and total volume error. Overall simulation time with 2000 model simulations was 11 days, which can be improved significantly under parallel computing, as GA-HSPF simulations are highly independent. The objective function ceased improvement after approximately 250 simulations, with a minimized MAE of 25.8 m3/s. With the exception of DEEPFR, all optimized model parameter values were within the range cited in the literature. Nash-Sutcliffe coefficients in all simulations were above 0.5, suggesting that the simulated flows were in good agreement with the observed flows. Visual comparison between observed and simulated stream flow using time series and flow duration curves showed that the GA calibrated model was unable to simulate peak flow events accurately, particularly in the 0% to 10% exceedence range. It is hypothesized that the storage-based routing scheme in HSPF limits its ability to predict peak flows in this watershed. Comparison between observed and simulated flows in the wavelet domain indicated that the GA calibrated model was not able to preserve the scale and location of some high frequencies, but the scale and location of lower frequencies were preserved. The cyclic nature of the streamflow in this watershed was more prominent in lower frequencies. While overall flow rates were adequately predicted using a GA-HSPF approach, future work in this watershed needs to focus on multi-objective optimization that optimizes both volumes and peak flows. The GA-HSPF model offers an objective and efficient method for calibration and validation, a useful tool in watershed planning efforts.

기후변화 및 도시화를 고려한 수자원관리 대안의 효과 분석

본 연구에서는 도시화와 기후변화에 대한 미래시나리오를 구성하고 각각의 시나리오별로 수자원 관리 대안들에 대한 효과분석을 수행하였다. 기후변화 시나리오는 SDSM (Statiatical Downscaling Method) 모형을 이용하여 구축하였으며 도시화는 불투수면 모형(Impervious cover model, ICM)을 이용하였다. 안양천 유역에 대해 하수처리수 재이용, 저수지 재개발 대안들을 유황곡선(flow duration curve)과 BOD 농도지속곡선(concentration duration curve)의 변화측면에서 연속유출모형인 HSPF (Hydrological Simulation Program - Fortran) 모형을 이용하여 분석하였다. 그 결과, 시나리오별 하천 유출량에 대한 대안 효과의 차이가 고수량 (<TEX>$Q_{10},\;Q_5,\;Q_1$</TEX>)에 비해 저수량(<TEX>$Q_{99},\;Q_{95},\;Q_{90}$</TEX>)과, 수질오염(<TEX>$C_{30},\;C_{10},\;C_1$</TEX>) 측면에서 크게 나타남을 알 수 있다. 즉 도시화는 물 순환을 크게 악화시키나 대안의 적용이 이러한 현상을 크게 막아줌을 알 수 있다. 또한 목표 유지유량 및 목표 수질 만족일수는 도시화에 대해 매우 민감한 것으로 나타났다. 따라서 향후 수자원 관리 대안을 수립할 때 기후변화와 도시화에 대한 분석을 포함시키는 것이 바람직하다. This study derived the analysis results of alternatives for integrated watershed management under urbanization and climate change scenarios. Climate change and urbanization scenarios were obtained by using SDSM (Statistical Downscaling Method) model and ICM (Impervious Cover Model), respectively. Alternatives for the Anyangcheon watershed are reuse of wastewater treatment plant effluent, and redevelopment of existing reservoir. Flow and BOD concentration duration curves were derived by using HSPF (Hydrological Simulation Program - Fortran) model. As a result, low flow (<TEX>$Q_{99},\;Q_{95},\;Q_{90}$</TEX>) and BOD concentration (<TEX>$Q_{10},\;Q_5,\;Q_1$</TEX>) were very sensitive to the alternatives comparing to high flow(<TEX>$C_{30},\;C_{10},\;C_1$</TEX>). Although urbanization makes the hydrological cycle distorted, effective alternatives can reduce its damage. The numbers of days to satisfy the instreamflow requirements and target water quality were also sensitive to urbanization. This result showed that the climate change and urbanization should be considered in the water resources/watershed and environmental planning.

An integrated framework for the hydrologic simulation of a complex geomorphological river basin

Summary The purpose of this study was to simulate the surface and groundwater flow in a karstic river basin where flood phenomena appear from time to time. The Koiliaris River Basin is located east of the city of Chania on the island of Crete in Greece. This river basin has a complex hydrogeology that consists of temporary – ephemeral rivers (tributaries), high mountainous karstic areas, springs, downstream karstic areas and karstic channel parts. In order to simulate all of these processes, a combination of four models was employed. The four models used in the present study were: (a) a two-part Maillet karstic model, used to determine the spring discharge, (b) a GIS-based Energy Budget Snow Melt model, developed to simulate the snow melt rate and compute the snow melt flow that enters the karstic system of the high mountainous area, A matlab code developed in this work combines the previous two independent models, (c) an empirical karstic channel model, developed to simulate the flow in the downstream karstic part of the Koiliaris River Basin, and (d) the Hydrological Simulation Program – FORTRAN (HSPF) model was used to model the hydrology of the watershed. Besides the karstic model, developed in this work, a significant contribution is that for the computation of the snow melt rate the energy budget considers the topography of the area (using GIS) that is incorporated with seven important parameters: elevation, slope, curvature, aspect, illumination, land use, and radiation. The main steps of this study included calibration, validation and sensitivity analysis of the HSPF model. The simulated results are in a very good agreement with the observed field data.

Calibration of the HSPF model with a new coupled FTABLE generation method

The hydrological simulation program FORTRAN (HSPF) is a comprehensive watershed model designed to simulate water quantity and quality processes. It is used widely throughout the world. Calculating discharge from a stream reach by HSPF is based mainly on function tables (FTABLEs), which describe the relationship between surface area, stream stage, volume, and discharge. The traditional method of FTABLE generation (using general stream cross-sections and the Manning equation or other discharge relationships) can be time-consuming and inaccurate when there are limited calibration stations and survey data. Recent insights into generalized coupled stage/storage and stage/discharge relationships, however, offer the potential to improve both the speed and accuracy of compiling FTABLEs and thus HSPF models. This study tested the application of these insights in generating FTABLEs. The study domain included 18 gauging stations in a coastal plain environment on the Peace River watershed in West-Central Florida. In the calibration of this model, wetlands were treated as reaches in HSPF with storage-attenuation characteristics. Over the simulation period, the modeled daily flow and stage correlated well with observed data at all gauging stations along the Peace River. The Nash-Sutcliffe efficiency and correlation coefficient computed using observed and simulated daily flows were 0.90 and 0.91, respectively, at the Peace River outlet. Rigorous testing found that the new system for calibrating the FTABLEs improved the model predictive ability and efficiency. Uncertainty in un-calibrated station performance was also reduced. The model parameters obtained in this study could potentially serve as reference values for model application in similar climatic regions. They may also have particular relevance in disaster management, as the simulation period extended over the hurricane season of 2004, and the model domain was within a high hurricane impact zone. The possible effects of hurricanes on discharge are also briefly discussed.

Multicriteria Review of Nonpoint Source Water Quality Models for Nutrients, Sediments, and Pathogens

Abstract There now exists a large number of nonpoint source models that have been developed for watershed management issues. As part of the National Agri-Environmental Standards Initiative (NAESI), it was necessary to evaluate which model or models would be the best choice for examining various best management practices for nutrients, sediments, and pathogens in test watersheds. Environment Canada has committed to the development of environmental performance standards that will guide environmentally sustainable agricultural practices and management. A literature review was carried out and a short list of 13 models was selected that met the basic needs of the project. These models were subsequently evaluated based on a multicriteria analysis that considered 21 model characteristics. A weight and a total score quantify the relative importance of each criterion. The top six models were SWAT (Soil and Water Assessment Tool), AnnAGNPS (Annualized Agricultural Nonpoint Source), BASINS (Better Assessment Science Integrating Point and Nonpoint Sources), GIBSI (Gestion Intégrée des Bassins versants á l'aide d'un Systéme Informatisé), AGNPS (Agricultural Nonpoint Source), and HSPF (Hydrologic Simulation Program - Fortran).

Modeling Climate Change Effects on Streams and Reservoirs with HSPF

This study deals with the effects of the expected climate change on the hydrology of watersheds and on water resources. HSPF (Hydrological Simulation Program—Fortran) has been used to model streamflow and reservoir volume as realizations of watershed response. Climate change scenarios have been prepared based on trends expected in western Turkey in the first half of the twenty-first century and a hypothetical watershed with different land uses has been simulated. Changes in streamflow due to landuse, soil type and climate change have been examined using flood frequency and low flow analysis. The simulations have revealed quantitatively the difference among the responses of watersheds with no vegetative cover and with forests or pasture to trends in temperature and precipitation. It has also been found that monthly variations are very important in predicting the future response of watersheds. Significant differences have been observed in streamflows and reservoir volumes on a monthly basis between scenarios, soil types and land uses. Though the effects of temperature and precipitation act to counterbalance their effects on a long-term scale, on a monthly basis they can act to reinforce their effects and create drought periods and floods.