Impact of LULC Dynamics and Climate Change on Streamflow Regime - A Case Study of the Budhabalanga River Basin on the East Coast of India

Intensifying anthropogenic activities to meet the demand of the burgeoning population has become a big challenge for watershed managers. Further, climate change aggravates the situation. Streamflow is the crucial parameter for maintaining and monitoring watershed health. It carries the signature of the cause and effects of various natural and human-induced processes occurring within the basin boundary. This study focuses on the influence of land use land cover (LULC) change and precipitation on streamflow with the help of remote sensing and hydrological modelling in the Budhabalanga River basin situated on the east coast of India. Google Earth Engine platform is used for the supervised LULC classification of the Landsat images for the years 2000, 2005, 2010, 2015 and 2020. The kappa statistics of 0.875, 0.850, 0.873, 0.89 and 0.895 is achieved for the classified LULC images of the year 2000, 2005, 2010, 2015 and 2020, respectively. The results of the LULC change study show that the built-up area increased by 53.04% during the period 2000 to 2020 in the study area. Soil & Water Assessment Tool (SWAT) is used to study the hydrological response of the river basin. The SWAT model was calibrated with daily streamflow data from 1995 to 2009 and validated for 2010 to 2017 with NSE > 0.65, R2 > 0.70, and PBIAS < ±10. Mann Kendall test was used to find the trend in the rainfall and streamflow for each sub-basin. Daily rainfall at four rainfall stations out of sixteen and daily streamflow at the Govindpur stream gauging station (main outlet) show an increasing trend at a 5% significance level. Partial least squares regression (PLSR) model and correlation analysis was carried out to find the influence of each LULC class on streamflow. The study revealed that the changes in the LULC in upstream catchments have significantly influenced the streamflow during the period 2000 to 2020.