DEVELOPMENT OF MODELS AND CONSERVATION PRACTICES FOR WATER QUALITY MANAGEMENT AND RESOURCE ASSESSMENTS
Location: Grassland, Soil and Water Research Laboratory
Title: Development of an automated procedure for estimation of the spatial variation of runoff in large river basins
Submitted to: Journal of Hydrology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 3, 2008
Publication Date: September 15, 2008
Citation: Kannan, N., Santhi, C., Arnold, J.G. 2008. Development of an automated procedure for estimation of the spatial variation of runoff in large river basins. Journal of Hydrology. 359(1-2):1-15.
Interpretive Summary: The Conservation Effects Assessment Project (CEAP) was developed to determine the environmental impact of USDA conservation practices in the U.S. A modeling system was developed to take climate, soils, topographic and land management information and determine the fate and transport of sediment, nutrients and pesticides in the nation’s waters. To assure accurate results, the model is calibrated and validated with measured data. Using current calibration procedures, the calibration process can take days to run on a desktop computer. In this study, an automated calibration procedure was developed that is efficient (running in a few hours instead of days or weeks) and gives satisfactory results. The new procedure is simple, efficient and improves spatial accuracy of model calibration.
The use of distributed parameter models to address water resource management
problems has increased in recent years. Calibration is necessary to reduce the uncertainties associated with model input parameters. Manual calibration of a distributed
parameter model is a very time consuming effort. Therefore, more attention is given to
automated calibration procedures. This paper describes the development and demonstration of such an automated procedure developed for a national/continental scale assessment study called Conservation Effects Assessment Project (CEAP). The automated procedure is developed to calibrate spatial variation of annual average runoff components for each USGS eight-digit watershed of the United States. It uses nine parameters to calibrate water yield, surface runoff and sub-surface flow respectively. If necessary, the procedure uses a linear interpolation method to arrive at a better value of a model parameter. When tested for the Upper Mississippi river basin of the United States, the automated calibration procedure gave satisfactory results. Other test results from the
procedure are very encouraging and show potential for its use in very large-scale hydrologic modeling studies.