A validation study has been performed using the Soil and Water Assessment Tool (SWAT) model with data collected for the Upper Maquoketa River Watershed (UMRW), which drains over 16,000 ha in northeast Iowa. This validation assessment builds on a previous study with nested modeling for the UMRW that required both the Agricultural Policy EXtender (APEX) model and SWAT. In the nested modeling appr...

Models of habitat selection have been developed primarily for mobile animals with well-defined home ranges. The assumptions made by traditional techniques about habitat availability are inappropriate for species with low mobility and large home ranges, such as the wood turtle. We used paired logistic regression, typically used in medical case 2 control studies, to model selection of habitat wit...

Watershed models have been widely used for creating the scientific basis for management decisions regarding nonpoint source pollution. In this study, we evaluated the current state of watershed scale, spatially distributed, process-based, water quality modeling of nutrient pollution. Beginning from 1992, the year when Beven and Binley published their seminal paper on uncertainty analysis in hyd...

the estimation of instantaneous peak discharge is important for watershed management because there is ainsufficient climatic and hydrologic data in countries such as iran. researchers have been forced to link constantparameters (geomorphology) and variable parameters (hydrology) to models with minimum dependence on climaticand hydrologic data for hydrologic estimation. the present study used a ...

Watershed delineation is a process for defining a land area that contributes surface water flow to a single outlet point. It is a commonly used in water resources analysis to define the domain in which hydrologic process calculations are applied. There has been a growing effort over the past decade to improve surface elevation measurements in the U.S., which has had a significant impact on the ...

Soil erosion has been recognized as one of the major threats to our environment and water quality worldwide, especially in China. To mitigate nonpoint source water quality problems caused by soil erosion, best management practices (BMPs) and/or conservation programs have been adopted. Watershed models, such as the Annualized Agricultural Non-Point Source Pollutant Loading model (AnnAGNPS), have...

Calibration of large watershed models requires multi-gage calibration, however there are limited tools available for performing these calibrations of SWAT models. Non-Dominated Sorting Genetic Algorithm II (NSGA-II) has been shown to be an effective and efficient multi-objective calibration algorithm in various disciplines. Although NSGA-II has been used with SWAT before, there is no publically...

Water quality modeling efforts for developing total maximum daily loads often use geographical information system data of varying quality in watershed-scale models and have shown varying impacts on model results. Several streams in the southern Piedmont are listed for sediment total maximum daily loads. The objective of this study was to test the effect of spatial resolution of soil data on the...

Accurate predictions of sediment yield from distributed models of runoff and sediment yield depends in part of how well matched the model structure is to input data spatial representation. This study investigated how model structure and input data representation affect sediment predictions made using the Soil and Water Assessment Tool (SWAT). The study focused on the integration of two specific...