Three Gorges Reservoir (TGR) area, China. Based on 108 effective rainfall events from 2021 to 2023, runoff and sediment data from six land use plots and one bare slope (BS) control plot were analyzed, together with rainfall classification and characteristics. Key indicators including critical rainfall thresholds, runoff and sediment yield, and reduction efficiencies were compared across rainfall types, and the contributions of measure type, rainfall pattern and their interaction were quantified. Type A rainfall dominated slope runoff and sediment production despite the high frequency of Type C events. Conservation measures raised critical rainfall thresholds to 2.0–4.6 times that of BS and reduced sediment yield by 4.79–13.24 times under different rainfall types. Under Type A, B, and C rainfall events, sediment yields from BS exceeded that of conservation plots by factors of 4.79, 8.12, and 13.24, respectively. The evaluated conservation measures achieved average runoff reduction efficiencies of 60.48 %, 74.53 %, and 75.83 %, and average sediment reduction efficiencies of 78.83 %, 93.22 %, and 89.58 % under type A, B, and C, respectively. Over 90 % of total sediment was generated by only five extreme rainfall events. Measure type, rainfall pattern and their interaction explained 81 %, 13 %, 6 % of runoff reduction efficiency and 41 %, 23 %, 36 % of sediment reduction efficiency. These results support regional soil and water conservation planning and integrated erosion control. • Type A drives 59∼99 % sediment yield, measures raising erosion thresholds 2.0–4.6 times. • Conservation measures achieve 69.02 %/84.44 % mean runoff/sediment reduction. • Woodlands require 3-year establishment; extreme events contribute > 90 % total sediment.
Li et al. (Fri,) studied this question.