Abstract: Xiangjiaba Reservoir and Xiluodu Reservoir have successively entered impoundment stage since 2012, and in the meantime intercepted sediment from the lower Jinsha River. According to field data of runoff, sediment and some cross-sections, the amount and distribution features of sediment deposition in the cascade reservoirs since their operation are calculated, and their influences on the Three Gorges Reservoir (TGR) are studied. Results indicate that sediment deposition in Xiluodu Reservoir and Xiangjiaba Reservoir are both less than the estimated amount. The cascade reservoirs reduced the incoming sediment of TGR, and correspondingly reduced the deposition in its tail reach. The research results are of great significance for the operation of cascade reservoirs and the regulation optimization of TGR.

Key words: hydropower stations in the lower Jinsha River, cascade reservoirs, sediment deposition in reservoir, Three Gorges Reservoir, runoff and sediment