| China, one of the water-shortage countries in the world, is rather abundant in total water resources volume, but poor in per-capita resource volume. Average per-capita of water resources in China is only one fourth of that of world average, ranking 122nd in the world. There are 60% cities among all cities of the country encountering severe water supply shortage, among which 110 cities are particularly serious in water shortage. The water deficit of all cities in the country is enormous, up to 60 billion per cubic meter in annual amount.Wifang city is seriously short in water resources, having an obvious contradiction of water supply and demand. There is uneven interannual and seasonal distribution of water resources in different areas in this city. The precipitation in flood season accounts for 3/4 of that throughout the year, and natural runoff volume accounts for 4/5. Since the fall of 2013, Weifang city suffered continuous droughts, which are the most severe ones since the founding of new nation. The annual rainfall of whole city is only 539.9 millimeters, reaching the lowest point compared to the precipitation of the corresponding period according to hydrological data recorded since 1952. Reservoirs are in serious shortage in water and the city suffered a shortage in water supply, too. Xiashan Reservoir and Bailang River Reservoir are the two largest water sources for water supply in Weifang city. Apart from dead storage capacity, the water supply capacity of these two reservoirs is 126 million per cubic meter till August,2014, but it can hardly meet the water demand by local industry, agriculture and urban life. Xiashan reservoir is the largest reservoir project in Shandong Province. The average annual volume of surplus water from 1960 to 2013 is 202 million per cubic meter,369 million per cubic meter from 2003 to 2013 and even 1 billion and 118 million per cubic meter in 2008, a single year. From these data, it can be drawn a clear conclusion that a plenty of water in flood season wasn’t taken full advantage of. Therefore, it turns out to be an important method and practical choice to solve the problem of water shortage in Weifang city by raising water levels of reservoirs to convert part of the rain and flood resources into available water resources and supply sufficient water to right place in right time, in order to maintain the city’s economic and social development and the eco-environment’s virtuous cycle.This paper will take Xiashan reservoir for an example, calculating and operating conservancy regulation of the reservoir before and after capacity increase, analyzing water supply benefits after raising the normal water level by 0.6 meter. Calculating and adjusting by chronological series method is based on analysis of water storage and supply situation from 1951 to 2011 (hydrological years) of current Xiashan reservoir. After concise calculation, by raising the water level from 37.4m to 38m, the average annual water supply capacity will increase 38.91 million per cubic meter and the largest increased capacity in high flow year will be 6.49 million per cubic meter, which will help Xiashan reservoir create more water supply benefits. |
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