Hydrological modeling with respect to impact of land-use and land-cover change on the runoff dynamics in Budhabalanga river basing using ArcGIS and SWAT model

Catchment area is observed to be standard unit for management of the natural resources. The origin of catchment area parameters using Remote Sensing (RS) and Geographical Information System (GIS) and use Soil Conservation Services Curve Number (SCS–CN) methods is the running trend for hydrologic estimation of catchment areas. Urban runoff increases significantly due to increased impervious area and decreased the forest area. Estimation of land use in built-up area plays a vital role as input to the evaluation of runoff. The broadcast specification model Soil and Water Assessment Tool (SWAT) has been tested on monthly basis for evaluating surface runoff from a small gauging station of Govindpur in NH5 road located along the Budhabalanga river basin. By using the GIS technique there have been generated several maps like watershed boundaries, drainage line, land use/cover, soil map and slope map. Potential of the model for generating rainfall has been calculated for 6 Years interval (2000, 2006, 2012 and 2018) period. The results depict that SWAT model usually performs well in simulating runoff according to Nash-Sutcliffe Efficiency (NSE) and Coefficient of Determination (R2) values. For monthly stream flow the NSE and R2 values were 0.827 and 0.957 during the simulation period respectively. The results of the study indicated that the though land use patterns have changed resulting in increase in agricultural, built-up, water land and decrease in forest and barren land.