Assessing the effectiveness of watershed management projects and their influence on watershed hydrology is essential for achieving sustainable water and land management. This study aimed to evaluate the hydrological impacts of implemented watershed management interventions in the Fariman Dam watershed. Hydro-meteorological data, including streamflow and sediment records, were collected from monitoring stations for periods before and after the watershed management measures were executed. Statistical analyses were conducted to compare pre- and post-intervention data, employing the Mann-Kendall trend test and Sen’s slope estimator to detect trends and quantify changes, respectively. Flow duration curves were also generated to assess alterations in flow regimes. The results indicated that the mean streamflow decreased from 0.52 m³/s to 0.3 m³/s and the average sediment yield declined from 5.8 tons/day to 0.78 tons/day after the interventions; both reductions were statistically significant. Annual precipitation exhibited no significant trend over the study period, underscoring that observed changes stem from the management measures rather than climatic variability. Furthermore, the flow duration analysis revealed a reduction in the probability of both high-flow floods and hydrological droughts following the implemented projects. Analysis of maximum instantaneous discharge across various return periods showed an increased frequency of low discharges (short recurrence intervals) and a decreased frequency of high discharges (long recurrence intervals). Overall, watershed management measures in the Fariman Dam watershed have demonstrably and effectively reduced streamflow and sediment loads, improving hydrological stability in the region.