The authors analyzed the data and problems of Sanmenxia reservoir operation since 1974 and demonstrated the capacity of sediment transport of the lower reaches downstream of Tongguan station when practicing the mode of "impounding clear water and releasing muddy water".

The conclusions are as follows: a) the two-reservoir operation has changed the annual runoff distribution of inflow and outflow of the reservoir and the runoff proportion of the flood season reduced from 60% before the reservoir to about 40%;the duration of big outflow discharge has reduced and the duration of small discharge increased;the o.

The incoming sediment from upstream of Tongguan is the unique source to leading the Tongguan river bed rising,but it is the only source of silt body to balance the impact on Tongguan river bed between the incoming water and reservoir operation mode.

Research method on reservoir operation performance in drought;

The key indexes commonly used to express characteristics of reservoir operation performance during drought are described,and their practical formulas,which are easy to deal with for computation procedure,are proposed.

According to the study on the highway soil bank slope in the areas of Three Gorges,through the influential effect analysis of the action of reservoir water,the parameter and index assessment system and the corresponding grading standards of bank slope stability analysis are established.