Evaluating Hydrological Model Performances on Stream Flow Simulation with Agricultural Management

Abstract

Two comprehensive agricultural watershed-scale hydrological models: Soil and Water Assessment Tool (SWAT), and Annualized Agricultural Non-Point Source Pollution Model (AnnAGNPS), have been widely used for evaluating agricultural Best Management Practice (BMP). In this study, models were developed for the Big Sunflower River Watershed (BSRW) in Mississippi, USA. Both hydrological models were successfully calibrated and validated for predicting monthly stream flow discharges from three USGS gages (Merigold, Sunflower, and Leland) within the BSRW. The model performances were reasonable with R² and NSE values range from 0.45 to 0.84 for SWAT, and from 0.34 to 0.66 for AnnAGNPS. Both models predicted lower stream flow discharge with conservation tillage practice as compare to conventional tillage practice BMP evaluated in this study. Overall, results showed that both SWAT and AnnAGNPS models successfully simulated hydrological conditions of the watershed with agricultural BMP, and these models can be useful for making hydrological decisions related to agricultural watershed managements.

Keywords: SWAT, AnnAGNPS, tillage, streamflow, hydrology, BMP

DOI: 10.7176/JEP/12-3-03

Publication date: January 31^st 2021