Rainfall runoff modeling in agricultural watershed using 2D shallow water equations

摘要

A 2D numerical model based on shallow-water equations is used for rainfall-runoff modeling. The rainfall intensity and infiltration rate are added as source and sink terms in the continuity equation. The Green-Ampt method is used for calculation of the infiltration rate. The model considers the spatial variability of rainfall, infiltration parameters and the Manning's friction coefficient. The GIS layers such as DEM, soil type, and land use can be directly used as input for the model. Spatio-temporal distribution of the rainfall over the watershed is determined based on rain gauge records. The model is applied to Goodwin Creek experimental watershed located in northern Mississippi. The model parameters are first calibrated using a single storm event. Using the calibrated parameters, the model is then applied to a serried of consecutive storm events. The comparison of computed and measured runoff discharge at the outlet of the watersheds shows good agreement. The results of this study indicate that this model can be used for modeling rainfall-runoff in large watersheds based on a historical or predicted rainfall distribution.