Assessing The Implications of Extension of Rubber Plantation on The Hydrology of Humid Tropical River Basin

The impacts of land cover change on the hydrologic cycle from local to regional scales are not fully understood with regard to humid tropical river basins of Kerala, India. This study provides an approach to identify the effects of land cover changes on streamflowof a river basin in the humid tropical zone of Kerala, India using the Soil and Water Assessment Tool (SWAT).The SWAT model was calibrated and validated for two river gauging stations for a period of 18 years (1987 – 2004).The model performed well for predicting the streamflow in Meenachil river basin under changing landcover conditions. The study carried for temporal variation of the surface runoff and evapotranspiration showed that more water is lost by evapotranspiration from the rubber plantation than that from the mixed crop cultivated landscapes. This supports the popular saying of the local people that rubber plantations act as “water pumps”.