Impact of Land use Land Cover Change on Streamflow of upper
Baitarani River Basin using SWAT

Abstract

Change in land use and land cover(LULC)pattern influences the hydrology of a watershed by altering its stream flow and groundwater characteristics. This study focuses on LULC change impact on streamflow of the Upper Baitarani river basin in India using Soil and Water Assessment Tool (SWAT). Initially,SWAT is run on daily time step using land use data of 1995 and 2013, slope and soil data for 1979-2013 with a warm-up period of five years to obtain the simulated streamflow. Sensitivity analysis is performed to identify the most influential parameters for streamflow. Calibration and validation are carried out using global sensitivity approach of Sequential Uncertainty Fitting (SUFI2) algorithm in SWAT Calibration and Uncertainty Procedure (SWAT-CUP) software. The simulated streamflow resulted from 1995 land use are calibrated for the period 1986-1992 and validated for 1993 -1995 using observed daily streamflow data at Anandapur hydrological gauge station. On the other hand, the simulated streamflow which are obtained from 2013 land use, are calibrated for the period 2004-2010 and validated for 2011-2013. The objective functions in terms of R2, NSE, PBIAS and RSR in SWAT-CUP shows the SWAT model has worked satisfactorily. Results show in eighteen years (1995-2013) the built-up area has increased by 8.26% whereas forest cover, barren land, and agricultural area have decreased by 0.59%, 1.62%,and6.18% respectively. To assess the impact of this LULC change on streamflow, calibrated SWAT model is run under two scenarios (climate of 2008-2013 with 1995 LU data and climate of 2008-2013 with 2013 LU data)on daily time step. The comparison between streamflow resulted from 1995 and 2013 LU data, shows due to LULC change (mainly urbanization) 2013 LU scenario has more annual average streamflow than 1995 LU scenario. The average increment in annual streamflow for 2008-2013 in the Upper Baitarani basin is 6.73%.