STUDY OF THE ENVIRONMENTAL STATUS OF FOUR RIVER SYSTEMS USING REMOTE SENSING DATA AND GIS

Funding Agency: Ministry of Environment and Forests, Government of India

Land and Water are the two basic components that support the very foundation of any economy. The uniqueness of the inter-linkage is manifested by river basins, which not only control the diversity of the surface of the earth but also act as a definite determining factor of land use structure. The water system of Kuttanad is mainly controlled by four river systems originating from the Western Ghats region viz., Meenachil, Manimala, Pamba and Achenkovil, which ultimately drain into Kuttanad. Many studies have been carried out in Kuttanad but a comprehensive study covering the upstream of the catchment areas of the river systems to the downstream is essential for formulation of management action plan for the area. This project studies the environmental aspects of the entire area with a Systems Approach to evolve a detailed Action Plan for Conservation and Management of the Hill system as well as the unique ecosystem of Kuttanad. The main objectives were to study the change in land use, geomorphology, soil and drainage pattern of catchment areas of four river systems draining into Kuttanad using Remote Sensing Data and Geographical Information System (GIS), to study the influence of land use changes on flood zones by comparing the land use changes and flood zones from remote sensing data and rainfall data over the years, to identify ecologically fragile zones both in the upstream and downstream areas of Kuttanad especially the four river basin areas, to assess the special hydrologic characteristics of the backwaters and the rivers discharging into it with special reference to rainfall, run off, evaporation, infiltration etc., to assess the quality of water in the river basins in terms of physical, chemical and biological factors; assessing the dispersion and relative influence of pollutants arising from various natural and man made activities in the upstream and downstream of the river catchments and suggesting measures for improvement in water quality, to formulate Catchment Area Treatment Plan and Eco-development in the upper catchments of the four river systems and also to formulate sustainable development programmes for the six agro ecological zones of Kuttanad

The change in land use, geomorphology, soil and drainage pattern in both the upstream and downstream of four river systems and other areas of Kuttanad region were studied. Delineation of the boundaries of the Vembanad backwaters and the surrounding ecosystem wherever necessary was done using GTS maps, and satellite images. Collection, compilation and analysis of the available hydrological, meteorological, estuarine and hydraulic data from the different river basins draining into the Vembanad and from the backwaters were carried out. Evaluation of the impact of man-made activities like Thaneermukkom Regulator, Thottappally Spillway, Harbour at the Mouth (dredging operations), Coir Retting, reclamation of Lands etc., were done. Regular monitoring of water quality in different regions of the water bodies including the lake and other fresh water sources was carried out for all the seasons. Detailed study was conducted to assess the impact of land use changes, geomorphology, soil etc., both in upstream and downstream of the four river systems on the flood situation in Kuttanad using multidate remote sensing data. Based on the data collected and the analysis using GIS, the ecologically fragile and sensitive areas in both the upstream and downstream of Kuttanad were identified and a detailed Catchment Area Treatment Plan formulated.