Hydrological Model-Based Planning of Soil and Water Conservation Practices for Enhanced Watershed Saturation and Sustainable Development in a Semi-Arid Region

Abstract

Strategic use of Soil and Water Conservation (SWC) techniques is essential for the efficient watershed management and managing hydrological processes in semi-arid areas. This study elaborates on a scientific framework following ridge-to-valley approach for model based planning of land and drainage line treatments to develop a stage of watershed known as watershed saturation where maximum generated runoff is conserved while maintaining environmental flow downstream. Using Soil and Water Assessment Tool (SWAT), the study modelled hydrologic processes in the Chikkodi subwatershed- semi-arid region. Assessment of existing SWC measures (bunding, trenching, Checkdam, etc.) formed a key baseline analysis; revealed a significant 26.17% runoff reduction due to combined effect of existing SWCs and provided insights for subsequent planning. Based on model outputs, study recommends land treatment i.e. bunding and trenching in identified critical areas which effectively intercept the runoff at the source and maximize infiltration. Conservation of remaining runoff through drainage line treatments (check dams) are proposed as the next crucial step in the ridge-to-valley strategy. This work highlights the necessity for a science-based framework for the sustainable management of semi-arid watersheds, emphasizing that with improved watershed saturation, there is increased local water availability which supports environmental flow. By combining the assessment of existing treatments with hydrological modeling for proactive planning, the proposed methodology provides a flexible and transferable approach to SWC practices optimization in enhancing watershed water storage in similar semi-arid landscapes.