Hydro-geomorphological Analysis of a Water Logged area of South Tripura District using RS and GIS Technology

摘要

The main objective of the study was two-fold. First, to map the natural drainage course in the wetland and its catchments area and to prepare geo-morphological and ground water prospective map to explore and utilize the subsurface water potential for irrigation during Rabi season using RS and GIS Technology. Second, to compare the results of RS and GIS data with ground truth to explore the possible causes of water logging. The total watershed area contributing water to the wetland system is about 265001 ha. The core waterlogged area of the wetland ecosystem having an area of 1750 ha (31.46 %) is covering five revenue villages. Hydro-geomorphologic maps have been prepared depicting the important geomorphic units, landforms and underlying geology. Geomorphological and geological (lithology and structural geological) interpretations (visual) were made on LISS III as well as LISS IV imagery on 1:25,000 scale. These maps were verified with limited field checks. Geomorphologically the area is young and immature and landforms are mainly of erosional and depositional origin. Average depth to water level during pre-monsoon is 2.50m bgl and during post-monsoon season is 1.5m bgl. Because of alternate sandstone and shale layers of Dupitila and Tipam Sandstone formation, ground water prospect in this region is very good to moderate but in few places it is excellent. Presence of shale layer in near surface condition created water logging in some places especially where proper drainage is absent. It is found that most of the study area is good to very good in ground water prospect. So ground water can be used extensively for various purposes taking required measures for timely recharge of the aquifers.