This study evaluates the performance of four evapotranspiration methods (Priestley-Taylor, Penman-Monteith, Hargreaves and Makkink) of differing complexity in a semiarid environment in north China. The results are compared to observed water vapour fluxes derived from eddy flux measurements. The analysis became necessary after discharge simulations using an automatically calibrated version of th...

The SWAT (Soil and Water Assessment Tool) model was used to estimate terrestrial sediment and nutrients loads to the Galveston and Matagorda bays from their contributing watersheds. In this report, the term "terrestrial loads" represents the sum of gauged loads from gauged subbasins and model-generated loads from ungauged subbasins. Because we did not have access to the point sources data, the ...

The Soil and Water Assessment Tool (SWAT) nitrogen (N) water quality model considers the artificial inputs associated with human activities, including point and nonpoint source pollution loads. Although SWAT has the ability to simulate atmospheric N deposition and fixation, they were not considered in the modeling research. N deposition from the air is an important and considerable pathway for ...

Spatial accuracy of hydrologic modeling inputs influences the output from hydrologic models. A pertinent question is to know the optimal level of soil sampling or how many soil samples are needed for model input, in order to improve model predictions. In this study, measured soil properties were clustered into five different configurations as inputs to the Soil and Water Assessment Tool (SWAT) ...

Rapid land use change due to intensive agricultural practices in the Ethiopian Highlands, results in increasing rates of soil erosion. This manifested in significant impacts downstream by reducing the storage capacity of reservoirs (e.g., Roseires, Sennar), and high desilting costs of irrigation canals. Therefore, this paper aims to provide a better understanding of the process at basin scale. ...

Implementation of sensitivity analysis (SA) procedures is helpful in calibration of models and also for their transposition to different watersheds. The reported studies on SA of Soil and Water Assessment Tool (SWAT) model were mostly focused on identifying parameters for pruning or modifying during the calibration process. This paper presents a sensitivity and identifiability analysis of model...

This paper describes the effect of DEM data resolution on predictions from the SWAT model. Measured hydrologic, meteorological, watershed characteristics and water quality data from Moores Creek watershed (near Lincoln, AR, USA) were used in the simulation. The effect of input data resolution was evaluated by running seven scenarios at increasing DEM grid sizes (30 ð 30 m, 100 ð 100 m, 150 ð 15...

Environmental models typically possess large uncertainty due to contributions from model structure, assumptions, parameterization, and data errors, not to mention lack of consideration of problem framing and the associated choice and justification of objective function. Sensitivity analysis (SA) is a fundamental tools to help identify uncertainties relevant to the modelling objectives. It provi...