Abstrcat The water loss and soil erosion on the Loess Plateau severely hampers the development of local economy and society. Therefore

a lot of measures of soil and water conservation are carried

and obvious benefits of sediment deduction are achieved. However

there are no reasonable methods considering the effect of soil and water conservation on the design of water conservancy projects

especially on the determination of mean annual sediment discharge for reservoir design. With two cases of reservoir design

considering the effect of soil and water conservation as well as ecological construction

the reasonable calculation ways of reservoir mean annual sediment discharge are discussed by means of comprehensively analyzing measured sediment deposition data in building reservoirs and sediment discharge records from hydrologic stations in similar watersheds