Influence of Operation of Main Reservoirs on the Yellow River on Runoff

The paper analyzes the influence of variations of storage of three multi-purpose reservoirs of Longyangxia, Liujiaxia and Sanmenxia located on the main Yellow River on its runoff. The results are shown as follows: ① The building of the 3 reservoirs has changed monthly correlation coefficient of runoff observed by hydrometric stations on the upper and lower reaches. Before the storage, the correlation coefficients of observed runoff of 2 stations on the upper stream and downstream of the reservoir are very big, but reduced after storing. ② The proportion of observed runoff of the downstream reservoir in flood season with annual runoff is getting reduced and increased in non flood season. The variation ranges of reservoirs are different. ③ The peak cutting effect is related with inflow and reservoir operation. ④ The operation of multi-purpose reservoirs has changed the exchanging period of waters of the main Yellow River and generated a certain influence on evaporation and percolation of the channel.