[Tim] net current situation analysis of water resources of the author: Tim net water purification Views: 283 Published: 2018-8-23 15:46:59 With the social and economic development, human demand for water is increasing . In this century the worlds fresh water usage increased 8 times, including a sevenfold increase agricultural water, urban water increased 12-fold, 20-fold growth in industrial water, and the worlds freshwater usage rate of 5% per year. Currently there are about 90 countries in the world, 40% of the population appear water crisis, three billion people lack water and sanitation facilities, there are 3000000-400 million people die from water-related diseases every year and, by 2005, the water crisis will spread to 48 countries and 35 million people trapped by the water. China is rich in water resources, but uneven distribution. A per capita basis, only about 75% and 35% of the world average Asian average (World Resources Institute, 1988). National total annual runoff is 2.71 trillion cubic meters, corresponding runoff is 284 mm, equivalent to 45% of the precipitation (Ministry of Water Resources Assessment >><< China 1992). About 65% of the land area of 鈥嬧€媡he outflow area, 35% of the inland river basin. Approximately 27% of the natural runoff (732 billion cubic meters) flow into the collar too, mainly international rivers southwest and northeast. Northwest of Hubei Irtysh River north into Siberia. Immigration is about 17 billion cubic meters of water, less than one percent of the total runoff. Glacier water storage is about 5.1 trillion cubic meters, the annual 56 billion cubic meters of water melted, about 20% of the total runoff of inland river. Groundwater recharge to 830 billion cubic meters, in the most natural conditions into river runoff, has been included in river runoff. Calculated by subtracting the amount of repetition, a net total water (surface water plus ground) was 2.81 trillion cubic meters, which is about 100 billion cubic meters of net groundwater. This is mainly due to rainfall infiltration plains formed, and almost all included mountain groundwater base flow, comprising in the runoff. The early fifties, the size of China 2480 natural lakes, lakes with a total area 83,000 square kilometers, of which, the surface area of 鈥嬧€媜ver 1 square kilometer lake is 2848, the total area accounting for 97% of the total area of 鈥嬧€媡he lake. Early in the last three decades, due to the sand and mud siltation, reclamation and other reasons, reduced lake areaLess than 12,000 square kilometers, with a total storage of about 709 billion cubic meters, equivalent to 17% of the total annual runoff.
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