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一、问题的提出为了防止推移质底砂及下层多砂水流进入取水构筑物,取含砂量少、颗粒细的上层水,取水构筑物要加设常水位进水口。但是,进水口设置高程现实情况采用得比较混乱,水位表示类型很多。如平均水位,多年平均水位、中水位、中常水位、中洪水位、频率50％水位及常年水位等,因此出现问题较多。如按中洪水位作为常水位进水口水位,则年利用率很低,经常取不上水。而按高于最低水位的水位设计则能取表层水的时间就很少,不能充分发挥经常水位取水口应有的效益。而对于常水位这个概念及推算方法的差异,往往是造成该取水口不合理设计的原因。经常有这种情况:同一段河流几个取水构筑物都取用常水位值,但高程相差很大。例如:某电厂和某钢厂取水泵房,建在
First, the problem is proposed in order to prevent the bed bottom sand and sand into the water intake of the lower multi-layered structure, take the sand with a small amount of fine upper water, water intake structure to increase the normal water level intake. However, the actual situation of setting the inlet height of the inlet is rather confusing and the water level indicates many types. Such as average water level, multi-year average water level, medium water level, medium and constant water level, flood level, frequency 50% water level, and perennial water level, so there are many problems. If the flood level is used as the water level at the inlet of the normal water level, the annual utilization rate is very low, and it is not always possible to take water. However, if the water level is designed to be higher than the minimum water level, there will be very little time to take surface water, and the benefits of regular water level water intakes will not be fully realized. The difference between the concept of constant water level and the method of calculation is often the cause of the unreasonable design of the water intake. It is often the case that several water intake structures in the same stretch of river use regular water levels, but the elevations are quite different. For example: a power plant and a steel plant pumping house, built in