Assessment of soil loss from a Trans-National Rapti River Basin using empirical and InVEST-based models
Adesh Patel, M. M. Singh, Shruti Bhatt, José Francisco de Oliveira-Júnior, Sudhir Kumar Singh, Vijay Kumar Singh Rathore, Suraj Kumar Sahu, Hrithik Sachan
Abstract
Presently soil erosion is a severe environmental issue. Human-induced activities and various natural processes have intensified it over time, making it one of the most concerning problem worldwide. The Himalayan River Rapti, has been selected for evaluating soil loss along with soil erosion rates using the Revised Universal Soil Loss Equation (RUSLE) in Geographic Information System (GIS) and the InVEST model. The results show that the minimum and maximum soil loss was estimated at 5 tons/hectare/year and 1185 ton/hectare/year, respectively, in the north-eastern (NE) and north-western (NW) sides of the Lesser Himalayan and Siwalik ranges situated in the upper Rapti River Basin (RRB). Three erosion susceptibility sites were identified in the RRB. The areas around Bhutwal and basin’s northern part experienced significantly intensive rainfall erosivity, whereas upper-middle to lower-middle sections of the basin exhibit relatively moderate to low intensity of rainfall erosivity. The large flatter alluvial plains are characterized by low (0.178 ton/hectare/year) erosion potential zones. Whereas the mountainous and foothills are represented by high erosion potential zones. The high sediment delivery (17,604.30 ton/hectare/year) was observed in the north along with north-east fringes of the RRB. While the low-lying flatter plains are represented by low sediment delivery (0.178). The Himalayan areas characterized by steep slopes are prone to erosion to a greater extent when contrasted with the flatter plains situated in the RRB. The results will aid in strategizing preventive actions against soil erosion and provide valuable information to planners for identifying areas of heightened soil erosion intensity. The higher degree of erosion could be minimized by introducing the agricultural activities and by enhancing the soil conservation practices and implementing effective watershed management.