Evaluating Effects Of Artificial Precipitation And Runoff By Man Of Longyangxia Reservoir

Longyangxia Reservoir in Qinghai Province on upper Yellow River is a large-hydroelectric station whose functions are included electric generation storage and flood protection, and once it have been brought huge economic efficiency. However water coming from upper Yellow River reduced year by year because of atmosphere exceptional changes in recent years, and the reservoir storage had occupied low water for a long time. Shorting storage has induced huge economic loss. Thus, it is very important that increasing storage of Longyangxia Reservoir by any means.Reservoir storage can be increased by many methods. But one of them which is economical and effective is to exploit aerial water resources. That is to say, increased runoff in the basin and the reservoir storage by manual intervention. The thesis is evaluated artificial rain effects on upper Yellow River in 1997.Effect evaluation is the key problem after artificial rain. And the precondition is to know natural precipitation during operation carried in operational area. The method based on terrain factors, such as longitude, latitude and altitude, to estimate the natural precipitation in operational area is not only used very well but also validated the applicability which can be used both in mountainous areas and great plains.In addition, compared analysis method and regressive analysis method are to be used to evaluate how much precipitation can be increased in the basin. And its attempted to seek the common law between multi-annual runoff coefficient and ratio of multi-annual evapotranspiration and the value of evaporation gauge at the same time in arid (half-arid) area and moist (half-moist) region, combined double-layer evaporation mode to compose a simple runoff model. The paper is chosen the simple runoff model and vertical-mixed runoff model to evaluate how much reservoir storage can be increased, the average increased storage of the two models is acted as the credible increased reservoir storage because of their respective structure mechanism. After calculation, the evaluation results are showed that the artificial rain on upper Yellow River in 1997 increases the precipitation in the basin and the reservoir storage. The artificial rain is successful and recommendable.