Study On The Water Supply Scale Variation And Its Influencing Factors In The Lower Yellow River

1 Since the 90s in the 20th century, the water supplies show the trend of decrease and irrigation area increasing in Quote Yellow River water irrigation area in the Lower Yellow River. On the basis of the large quantity of data, the reason why the scale of diversion is decreasing, it mainly is (1)water supply from the yellow river is decreasing year by year.(2) The coefficient of the irrigation water use is improving, (3) water resources from the local area increases.Inflow variation of the Yellow River is the main reason for the scale decrease in diversion in the lower reaches. Especially the irrigation season, unable to divert at the suitable time and quantity results to the diversion scale decreasing. The research shows that the agriculture irrigation is the supplementary irrigation; the rainfall is inversely proportional to the water needs in agriculture. Since the 90s, the rainfall shows the trends of increasing, which leads to the water diversion from the yellow river decreasing. At the same time, the experiment of Adjusting water and the sand relation leads to the river bed erosion and the diversion capacity reduce. In addition, because of not considering the silt rush out and erosion in the channel of the irrigation area at the end of the experiment, diversion channel is silted and some channel cannot be diverted.This paper adopts the analysis method of Multivariate Regression and Analyses the measured flow, the water resources utilization, the rainfall, irrigation area and water supply scale from the yellow river. The factorswhich are close to the water supply scale are the discharge and rainfall of the local area. The further analysis shows that the two influences the water supply scale equally.Through the expert evaluation, the step analysis model of water supply scale is build. Using Delphi method, I assign mark to each factor according to its relative importance, construct the comparisons and judge matrix and determine the relative importance of Factor stratification and Index stratification. In Author's opinion the main factors by order are discharge, rainfall in the local area, the channel condition, local water resources utilization and sluice diversion capacity.On the basis of the water supply scale analysis and its influencing factors, this paper presented some advice about improving water supply efficiency such as the direct supply to user patterns, adjusting Xiaolangdi run mode, management anticipation of the user, broaden the non-agriculture water supply and improve the water price gradually and so on.