Evaluating the Effectiveness of BMPs with Future Climate Scenarios in a Forested Watershed in Mississippi

Abstract

Abstract. Future climate changes, such as precipitation, temperature, and carbon dioxide (CO2) can have dramatic impacts on the hydrological cycle. These climatic changes can also increase the intensity and occurrence of peak flow events, which may cause damage to agriculture and infrastructure. This study is conducted in the Lower Pearl River Watershed (LPRW) in southern Mississippi, which is dominated by forests and pastures and is characterized by its high peak flows. The Soil and Water Assessment Tool (SWAT) was utilized to evaluate the performance of structural BMPs on attenuating peak flows under future climate scenarios. The SWAT model was calibrated and validated for streamflow at four United States Geological Survey (USGS) gage stations (Jackson, Strong River, Monticello, and Bogalusa) with good model performance based on the coefficient of determination, Nash-Sutcliffe Efficiency index, and root mean square error statistics. Future climate change scenarios were based on climate model projections of precipitation, temperature, and CO2. Observed daily precipitation and temperature data for the years 1981 to 2010 were used as inputs in the LARS-WG stochastic weather generator model to generate future climate data. The CO2 emission scenarios were incorporated in the SWAT model by increasing the average CO2 concentrations based on Inter-governmental Panel on Climate Change (IPCC) reports. The future climate scenarios were coupled with BMP implementation strategies (detention ponds, terracing, and grassed waterways) to quantify the effects on peak flow attenuation. This study will help to identify BMPs that have the greatest potential for reducing peak discharges in the LPRW.