Vishalkumar R. Gor^1,, Vinodkumar M. Patel²

Soil erosion is the most critical environmental problem in the semi-arid region of the sabarkantha-Aravalli districts of Gujarat state. The present study is carried out on micro-watersheds of Mazum and Vatrak tributaries of the Sabarmati river basin of Gujarat state, west India, having an area of 8638 sq. km. In this paper, the Universal Soil Loss Equation (USLE) model has been used to quantify soil loss in micro watersheds. Five essential parameters such as Runoff-rainfall erosivity factor (R), soil erodibility Factor (K), slope length and steepness (LS), cropping management factor (C), and support practice factor (P) have been used to estimate the soil loss amount in the study area. All of these factors have been calculated using various data sources and data preparation methods. The soil erodibility (K) factor in the study area ranged from 0.46 to 0.93. All essential parameters have been calculated for before-after watershed scenarios. Changes in soil erosion have been estimated after the implementation of micro-watershed development projects under various government schemes. The average annual predicted soil loss ranges between 45 and 230 t/ha/y before implementation and 14.50 and 138 t/ha/y after implementation. Low decreases in soil loss areas (<30%) have been recorded under very slopy undulating and less treated areas. The high rate of decrease (>111%) in soil erosion was found to have a good provision of land treatment with watershed interventions along the watersheds on the main course of the Mazum and Watrak rivers.

soil erosion, watershed development, USLE, Soil conservation, watershed conservation practices