Study on the sediment interception by reservoirs in the lower Jinsha River Basin
With the construction and operation of numerous reservoirs in the lower Jinsha River Basin,sediment retention by reservoirs has become the main reason for sediment reduction.From 1956 to 2021,a total of 504 reservoirs with a capacity of over 1 billion m3 were built in the mainstream of the middle Jinsha River and the Yalong River,and in the tributaries of the lower Jinsha River,with a total reservoir capacity of 68.76 billion m3.After the operation of the reservoirs,there is no significant change in the annual runoff of the lower Jinsha River,while the annual sediment transport significantly decreases.Sediment concentration in the LJRB has decreased significantly since 1998 and 2013,the average sediment concentration was reduced to 1.22 kg/m3 during 1998 to 2012 and 0.01 kg/m3 during 2013 to 2021 from the average value of 1.75 kg/m3 during 1956 to 1997.The contribution of reservoir sediment retention and soil and water conservation engineering to sediment reduction in the lower Jinsha River was analyzed using the double mass curve method and reservoir trap efficiency equation.The results show that the reduction of sediment in the lower Jinsha River is mainly caused by the retention of sediment by reservoirs.The average annual sediment reduction in the lower Jinsha River from 1998 to 2012 are 97 million tons,with the contribution of sediment reduction by reservoir retention of 0.67 and by soil and water conservation of 0.33.From 2013 to 2021,the average annual sediment reduction are 243 million tons,with the contribution of sediment reduction by reservoir retention of 0.97 and by soil and water conservation of 0.03.
lower Jinsha River Basinreservoirs distributionsediment retention effectrunoff and sediment change
万方数据
维普
