Role of remote sensing in demarcation of alluvial fan deposits in Tarai-Bhabar belt of Nainital District (U.P.) and the environmental impact assessment

Remotely sensed data has unique advantage aver conventional data collection techniques in the study of geomorphology, as physiographical and geo-structural parameters are mostly discernible on the imagery. In the present study an attempt has been made to identify and evaluate the process of geomorphological evolution and hydrogeological conditions, temporal changes in pattern of geomorphic elements and overall impact on environment in alluvial fan region in Nainital District using multidate satellite data from Landsat (1975, 1986) and IRS (1993), through visual interpretation technique. The landuse changes are quite prominent in alluvial fan of upper and lower zone. As a consequence of deforestation, an area of 16 sq. km. of natural forest cover has been lost over a span of 18 years (1975–1993) leading to the increase in rate of erosion as well as environmental degradation in upstream areas. The study suggests that the ground water utilization in Tarai belt without replenishment of confined aquifers and installation of more tubewells in Bhabar belt may lead to total failure of flowing wells and subsequently disturb the balanced ecosystem.