Recommendations to rejuvenate river bharathapuzha usin GIS and watershed simulation model

Abstract

Bharathapuzha, the second largest river of Kerala is the lifeline of several millions of people in the state, but now facing tremendous pressure due to encroachments, sand and clay mining and illegal diversions of water. One of the major issues of the river is that the river is live only during monsoon season and in summer, the flow is practically nil. Considering these circumstances, our study focused on measures for sustaining this water source round the year with the specific objectives of modeling the topography of the river using Geographical Information System (GIS), studying the existing flow pattern of the river using simulation model and on the light of the study, suggesting sustainable interventions to improve summer flow regimes of the river. The project area covers the entire catchment area of the river Bharathapuzha with 6186km 2 . Sub watershed delineation was the most important preliminary task involved in the whole exercise. For the quick and efficient delineation of micro watersheds, GIS and Soil and Water Assessment Tool (SWAT) were made use of. Micro watershed delineations and their topographic analysis have been carried out with the help of ILWIS and SWAT. Digital Elevation Model (DEM), drainage network, soil map and land use map for the catchment were prepared by utilizing the integrated GIS and image processing capability of ILWIS. SWAT was set up and calibrated for the basin with good simulation efficiency and the calibrated.s model was used to analyze the water balance of the whole basin and that of the individual subbasins. Based on the detailed hydrologic analysis at micro level, appropriate interventions to improve the summer flow regimes of the river is recommended.