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

The strategic use of Soil and Water Conservation (SWC) techniques is essential for efficient watershed management and hydrological processes in semi-arid areas. This study elaborates on a scientific framework following a ridge-to-valley approach for model-based planning of land and drainage line treatments to develop a stage of the watershed known as watershed saturation, where the maximum generated runoff is conserved while maintaining environmental flow downstream. Using the Soil and Water Assessment Tool (SWAT), the study modelled the hydrologic processes in the Chikkodi sub-watershed, a semi-arid region. The assessment of existing SWC measures (bunding, trenching, Checkdam, etc.) formed a key baseline analysis; it revealed a significant 26.17% runoff reduction due to the combined effect of existing SWCs and provided insights for subsequent planning. Based on the model outputs, this study recommends land treatment, that is, bunding and trenching, in the identified critical areas, which effectively intercept the runoff at the source and maximize infiltration. Conservation of the remaining runoff through drainage line treatments (check dams) is proposed as the next crucial step in the ridge-to-valley strategy. This study highlights the necessity of 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 practice optimization for enhancing watershed water storage in similar semi-arid landscapes.