Comparative Analysis of Runoff–Sediment Dynamics in Controlled and Uncontrolled Micro-Watershed

Abstract

This study investigates the runoff-sediment dynamics across three controlled micro-watersheds, with an uncontrolled micro-watershed serving as a reference. The event-based analysis was based on 9 years of monitoring data. The statistical and hydrological regime classification results indicated a significant difference in the distribution of regimes across watersheds. The controlled micro-watersheds showed reduced frequency of high runoff–high sediment regime by 23-26% and increased occurrence of controlled regimes by 10-17% points, compared to uncontrolled micro-watershed. Pairwise chi-square tests and higher residual values indicated that differences among micro-watersheds are primarily driven by variations in high-runoff and sediment events. These findings suggest that Best Management Practices (BMPs) not only help reduce sediment transport, but also redistribute the frequency of runoff –sediment response events. The observed responses are likely influenced by both BMPs and physiographic characteristics of the micro-watersheds. The study provides a strong scientific basis for watershed-scale BMP planning and sustainable sediment management.