CS(AR)-30/99-2000 : Soil erosion studies for forested watershed

Abstract

Soil erosion and sedimentation are the two important natural processes which need immediate attention from the scientific community. Two major types of erosion are geological erosion and erosion from human or animal activities Geological erosion includes soil-forming as well as soil eroding processes that maintain the soil in a favourable balance, suitable for the growth of most plants. Geological erosion has contributed to the formation of our soils and caused many of our present topographic features, such as canyons, stream channels, and valleys. Conversely human tillage or vegetation removal by animals or other natural events may cause accelerated erosion, which leads to loss of soil productivity.

Water erosion is the detachment and transport of soil from the land by water, including rainfall and runoff from melted snow and ice. Types of water erosion inter-rill (raindrop and sheet), rill, gully, and stream channel erosion. Water erosion is accelerated by farming, forestry, grazing and construction. Due to these activities in the upper catchments most of the reservoirs get silted up and the storage capacity gets reduced to a minimum. Therefore, it is necessary to understand the process of soil erosion and also to identify the erosion prone areas in the catchment.

In the present study an attempt is made to estimate the soil erosion rate in Malaprabha representative basin by using WEPP model and Universal soil loss equation. It is observed that the WEPP model results are more comparable with the actual erosion rate than USLE. However, due to lack of observed data study provide a general outlook of the severity of the soil erosion problem in the catchment. The study is carried out by Dr. B. K. Purandara, Sc 'B', with the assistance of Mr. N. Varadarajan, SRA Regional Centre, Belgaum.