Management of Soil Losses in South Mahanadi Delta, India

Arc GIS and RUSLE software’s are used for classification and estimation of the annual average soil loss of four watersheds in the South Mahanadi delta along east coast of India. The uplands between the distributaries constitute the West of Daya, Daya-Bhargovi, Bhargovi-Kushabhadra and the coastal watersheds. The major water shed is the upland bounded by the rivers Daya and Bhargovi which decant to the Chilika lagoon which has unique ecosystem and hotspot biodiversity. The lagoon receives 70-80% of its inland flow from the Mahanadi system. About 6-8% of total sediment of the total Mahanadi system debouches into the lagoon threating the lagoon to be a depleted wetland in future. The sediment due to reel and the gully erosion of the local catchments plays important role in soil management. To study the average annual loss of soil of the watersheds, the rainfall erodent factor (R), soil erosion factor (K), basin length (L), gradient (S), crop type coefficient (Cc), tilling practice coefficient (Cp) and support practice factor (P) have been derived using rainfall data, satellite imageries and agriculture statistics of the area. The West of Daya watershed shows higher soil erosion rate than others. The average erosion rate of the south Mahanadi delta is estimated as 8.347 MT/ha/yr. and the coastal sandy area as 0.393 MT/ha/yr. Management strategies for reducing erosion rate are check dams, stone terraces, contour ploughing and cultivating salinity tolerant crops by proper catchment treatment plan for the area.