Analysis On The Characteristics Of The Water Resources In The Loess Irrigation District On The Weibei Mesa

The water resources which is one kind of important natural resources, Especially in the edge of the loess plateau—the loess district on the Weibei mesa,appears particularly important. The paper in view of the characteristics of the water resources in the loess irrigation district on the Weibei mesa, including the precipitation, the surface water and the ground water characteristics, has made the comprehensive and systematic analysis, simultaneously studied the condition of the evaporation in the area. And basing on the condition of water resources development and use, the paper puts forward the sustainable use proposal.The paper puts emphasis on the analysis and study of precipitation resources and the characteristics of distribution in the area, including climate and precipitation characteristic, the change cycle of the precipitation and so on; simultaneously the paper has studied the distribution. The research indicated that: Average annual precipitation is 4.43 billion m3, which converts into annual precipitation depth, is 58.78mm. The distribution tendency of precipitation is decreasing from the mountainous area to the plain river valley, decreasing from the west to the eastern part. The average of Coefficient of variation is 0.24, which lies from 0.20 to 0.26 in the whole area, and the same time, the distribution of precipitation in a year is non-uniformity.In view of the characteristics of surface water resources, mainly including formation, distribution and regularity of runoff, the paper selects the typical rivers, analyzes regularity, and divorces different district to research the surface water resources, the research indicated: The average multi- annual runoff is 247 million m3, which converts into runoff depth is 31.2mm. The water volume which is consumed approximately is about 265 million m3 in a year, which is increasing year by year. The distribution of annual runoff of the main rivers is non-uniformity in a year. The runoff depth of most of places is lower than 50mm, and the distribution is non-uniformity, the regularity is that the depth in mountainous area is bigger than the one in original area, the depth in west is bigger than the eastern part. The regularity of evaporation volume is that which in summer is bigger than in winter, spring and autumn Period comes between them. The Coefficient of variation of Evaporation is between 0.09...