ESTIMATION OF SOIL EROSION & SEDIMENT YIELD USING GIS

Abstract

Problems associated with soil erosion, movement and deposition of sediment in watershed and catchment persist through the geologic ages in almost all parts of the earth. The situation is more aggravated in recent times with humankind's increasing intervention with the environment such as rapid transformation of virgin lands into agricultural use and also due to faulty agricultural practices, mismanagement and over exploitation of forests, over-grazing of pasture, mining, and developmental works but not accounting for counter mitigative measures. This environmental impact makes drainage network dry and consequently land slide problem commences and further increment in degradation and deterioration of watershed. At present, the quality of available data may be uneven. Land use planning based on unreliable data can lead to lots of expenditures and gross errors in results. Soil erosion research is a capital-intensive and time-consuming exercise. Global extrapolation on the basis of few data collected by diverse and unstandardized methods can lead to gross errors. Soil Erosion involves the processes of detachment, transportation & accumulation of soil from soil surface due to either of raindrop impact and splash, the shearing force of flowing water, wind, sea waves or moving ice. During- the process of erosion and transportation to downstream side, some part of the eroded material may get opportunity to deposit. The net amount of sediment flowing. through the watershed is termed as sediment yield. Empirical models such as Universal soil Loss Equation (LISLE), Modified Universal Soil Loss Equation (MUSLE) and Revised Universal Soil Loss Equation (RUSLE) are simple most commonly used soil erosion estimation models and are employed for quantitative assessment of soil loss. Soil erosion is a function of physical systems, such as climate, soil, crop and topography. Remote Sensing provides affordable and easy solution for capturing the authentic remotely sensed data. Voluminous data gathered with the help of remote sensing techniques are better handled and utilized with the help of Geographic 111 Information Systems (GIS). In this case, GIS Software helped to a great extent for assessment of soil erosion and sediment yield inventory and for their result analysis...