| Danghe River,located at the western end of Hexi Corridor in Gansu Province,is a first-grade tributary of the Shule River;meanwhile,it is also the main water source which maintains the stability and sustainable socioeconomic development of Dunhuang City,Subei Mongolian Autonomous County and Aksay Kazak Autonomous County.As the development of all cities within the Danghe River basin with sustained growth of population,economy,and agricultural acreage and cultivated land area increases constantly,the contradiction between supply and demand of water resources has become increasingly prominent.The continued deterioration of the basin ecology has already been a serious threat to urban safety and people's livelihood.The thorny problem that the local government can not avoid is how to strike a balance between social development,economic development and ecological protection within limited water resources for achieving the sustainable development of the whole basin.Based on the previous research results,this paper establishes the Water Evaluation and Planning System Model for the Danghe River basin by using the statistical data about water resources,social and economic development of for the Danghe River basin many years;moreover,this paper simulates the development of water resource and utilization of the basin in the future according to the current development trend.This paper discusses the sustainable development capacity of society,economy and ecology of the basin,and then calculates the maximum water saving capacity and water saving cost of the basin under the current technical conditions.Through simulation and calculation,this paper mainly comes to the following conclusions:1.If the impacts of the population growth within the basin is considered only,in view of high,medium and low population growth plans,the water consumption of urban and rural residents due to the increase of population will be about 340 m3,270 m3 and 240 m3 respectively by 2030,and the growth rate will be 47.89%,38.03% and 33.8% of the base year.Because the base number is small,the population growth has a relatively small influence on the balance between water supply and demand in the basin before 2030,but it still has a certain impact on the pipe network demand of water supply for urban and rural residents.2.If the impact caused by economic growth within the basin is considered only,in view of the high,medium and low economic growth plans,the water demands for economic development of Danghe River basin will reach 238 million m3,112 million m3 and 81 million m3 respectively by 2030,which are about 30 times,15 times and 10 times of the water demand for the economic development of the Danghe River basin in 2007 and occupies 67%,34% and 23% of the average inflow of the Danghe River separately for many years.As such,it will make a big difference in the balance of water resource within the base.3.By calculation,in accordance with the high,medium and low agricultural water-saving plans,332 million m3,298 million m3 and 280 million m3 of water can be saved respectively by 2030;the water demands for agricultural production will be 70%,63% and 59% of the base year.4.This paper stimulates and analyzes the eight plans of “inefficient agricultural water-saving plan under the conditions of high population and high economic growth”as well as the impacts under the combined effects of population,economic development and agricultural water-saving measures.If the rapid economic growths of all counties are still maintained,it is not conducive to the sustainable development of the basin.Supposin g that the ecological deterioration of the basin cannot be eased,it is possible to become worse.5.If the measure of saving water of the whole basin within an individual basin in the Danghe River is relied on merely,it will be not yet enough to solve the ecological deterioration problem in the Danghe River basin.The social,economic and ecological development of the basin will become unsustainable in the future. |
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