The reservoirs of Qingshuihe basin in Ningxia have important role on sediment-retaining effect

which is also an important factor to be considered in the revert calculation of sediment yield. However

how to calculate the annual sediment-retaining amount based on the total amount of sedimentation has ever been rarely reported. Based on the measured data

the basic situation was analyzed and the total sediment-retaining volume of the Qingshui River Basin reservoirs was estimated in this paper. Three factors of control area

average erosion intensity and sediment-retaining rate were introduced to establish the calculation formula for the annual sediment retention by reservoirs. Analysis based on statistics showed that there were 100 reservoirs in the Qingshuihe basin

the total capacity was 12.23×108 m3

the controlled drainage area was 9 184.70 km2

the total storage capacity was 1.235 billion m3

the sediment-retaining capacity was 686 million m3

and the sediment-retaining volume was 571 million m3

which accounted for 78.25% of sediment transported at Quanyanshan Hydrological Station in 1957 to 2012. The verification of the calculation results showed that the model had good calculation accuracy when the number of reservoirs was large and the distribution was relatively uniform. According to the calculation results

the sediment retaining volume of the reservoir was relatively large before 1979. Since 1960

the remaining sediment-retaining capacity of the reservoir declined. After 2000

the sediment-retaining ratio of the reservoirs remained about 83.00%

it showed that the reservoirs showed a limited capacity in the sediment-retaining.