Hydrologic Response to Land Use Change and Climate Variability in an Ungauged Basin, North-Western Himalaya, India

Hydrological models are overwhelmingly used for gauged basins to simulate variations in water balance components from environmental changes. In the present study, we used Soil and Water Assessment Tool (SWAT) to investigate the impacts of land use land cover (LULC) change and climate variability on hydrological regime of an ungauged river basin (Sirsa river) in north-western Himalaya, India for the period 1983–2008. The model was calibrated and validated (2004–2008) using MODIS actual evapotranspiration data (MOD16A2) with high monthly concordance (R2=0.81). The results showed that remotely sensed evapotranspiration data could be used as a proxy of gauge discharge data to calibrate the physically-based model. The substantial increase in built-up area (6.5%) and cropland (9.8%) over forest cover and barren land caused a corresponding increase in average annual surface runoff (12%) and a decrease in lateral flow (6.7%) from base level LULC of 1989 to 2009. The climate variability alone was found significant to reduce average annual streamflow (26.5%) in monsoon season (wet), baseflow (6.5%) and lateral flow (4.6%) in the dry period. As the water resources of the study area are expected to be adversely effected in the near future, this study will effectively benefit stakeholders and administrators for the management of water resources