Effect of Drainage Area Threshold on Stream Flow Modelling Using Arcswat

Abstract

The present study explores the effect of varying threshold values of drainage area on the stream flow and water balance characteristics of the Burhanpur sub-catchment in the Upper Tapi River basin, India. Stream network and flow characteristics were derived by threshold-based stream definition in ArcSWAT 2012.10_5.24 using Shuttle Radar Topographic Mission (SRTM) Digital Elevation Model (DEM) of 30 m resolution. The SWAT models with drainage area threshold values of 50, 100, 200, 300, 400, 500, 600 and 700 km2 were calibrated and validated on a monthly time scale. The performance of each model was evaluated in terms of statistical performance indices, i.e. Nash Sutcliffe Efficiency (NSE) and Coefficient of Determination (R2). All the models were found to perform efficiently in estimating the stream flow from the sub-catchment. The respective NSE and R2 values ranged between 0.8–0.85 and 0.84–0.89 during the calibration and 0.91–0.93 and 0.90–0.93 during the validation periods. The simulated stream flow and water balance were found to be optimum at 200 km2 drainage area threshold, both during calibration (NSE = 0.85 and R2 = 0.89) and validation (NSE = 0.93 and R2 = 0.93) period. The results imply that an appropriate drainage area threshold value has to be used to generate optimum stream flows and water balance to enhance the performance of hydrological models.