Study On The Eco-environmental Water Demand And The Sustainable Utilization Of Water Resources In River Basin

For a long time, human society predatory exploitation and utilization of waterresources has caused fluvial ecosystem varying degrees of damage, water has becomea "bottleneck" of some of the regions’ economic development. The middle and lowerreaches of GanJiang is the traditional four fish spawning grounds，it is also the mainsource of drinking water of the surrounding residents. Water resources of GanJiangmiddle and lower reaches are relatively abundant, but encountered dry years or dryseasons, various types of water diverted each other, the quality of water environmentdecline overall. If this phenomenon can’t be soluted reasonably, the water resourcessituation of the middle and lower reaches of GanJiang River Basin will graduallydeteriorate and sustained socio-economic development will be restricted. Therefore,Eco-environmental water and the sustainable use of water resources is an importantguarantee for the sustainable development of the middle and lower reaches ofGanJiang River Basin.This paper carried out detailed study in the progress of the domestic and interna-tional eco-environmental water, related concepts, characteristics, methods of com-putation of the ecological environment water. So eco-environmental water demand ofGanJiang middle and lower reaches divide into the inside river and outside river waterdemand. Based on the function of the river and the actual of GanJiang River Basin,the Eco-environment water requirement is divided into basic eco-environment waterof river, sediment transmission water, evaporation and seepage water, selfpurificationwater. Carring out reasonable test and dividing grade by the method of Tennant.Finally, according to compatibility characteristics of the instream Eco-environmentwater demand, Let the basic eco-environment water’s "ideal" and "appropriate" levelof the GanJiang middle and lower reaches as the the instream Eco-environment waterdemand, get the main control section of each grade eco-environmental waterallocation process during the year. Calculating outside river eco-environmental waterdemand and summing it with the instream Eco-environment water demand,determining in the present status year2010, the "ideal" and "appropriate" level Eco-environment water demand is169.09billion m~3and120.28billion m~3in the middleand lower reaches of GanJiang River Basin; In the planning year2030."ideal" and"appropriate" level Eco-environment water demand is171.69billion m~3and122.88billion m~3.The ultimate goal of Eco-environmental water research is providing reference forrational development and utilization of water resources, therefore, on the basis ofeco-environmental water, the paper will study sustainable utilization of water re-sources of the middle and lower reaches of GanJiang River Basin. Through thebalance analysis of water resources based on the available water resources and socio-economic water consumption in different hydrological conditions of the presentstatus year2010and planning year2030. We can draw that: in terrible dry years, ifkeep the ecological environment achieving "ideal" level, socio-economic waterwill be scarce. Therefore, it is recommended that in terrible dry years, we shouldadopt "appropriate" level of eco-environmental water for optimal allocation of waterresources. Each hydrological years of non-flood prone socio-economic water is scarce.Therefore, we need to take a series of measures to ensure the coordination of the"Sansei" water to achieve the sustainable use of water resources. Finally, somesuggestions are given according to the problems in studying.