Joint Assessment Of Ecological Water Demand And Quality And Water Resources Allocation In The Four Waters Basin Of Hunan Province

Wateris a basic natural resource,strategic economic resource and an part of the national comprehensive strength.It is not only related to the survival of human being,but also affects the economic and social development and the harmony of the natural ecosystem.There is an abundance of water resources in Hunan Province,however,the problems of water pollution,ecological destruction,waste of resources have become more and more serious.Meanwhile,this is the overwhelming fact that there has been a lot of cases squeezed out ecological water requirement by production and living water requirement.In view of the importance and the research status in Four Rivers(Xiangjiang,Zijiang,Yuanjiang,Lijiang)basin of Hunan Province.The ecological water requirement have been evaluated based on the joint of water quality and water quantity,by making full use of hydrological stations and water quality monitoring datas and national economic statistics in 2000~2015.And according to the results of joint evaluation of ecological water requirement,the supply and demand balance of water resources is analyzed in Xiangjiang River basin.Then the allocation of water resources in Xiangjiang River basin is preliminary studied in the layout years of 2020 and 2030.The main contents are as follows.(1)The ecological water requirement of the Four Rivers basin in Hunan Province,includes the basic ecological water demand in rivers and the water demand for sediment transport in flood season.And the ecological water requirement of Xiangjiang River,Zijiang River,Yuanjiang River and Lijiang River is 418.40 million m~3,291.02 million m~3,291.02 million m~3 and 101.50 million m~3,respectively.(2)The ecological water requirement is evaluated which based on dualistic water cycle by using the model of joint evaluation of water quality and water quantity.The results show that Yuanjiang River and Lijiang River can achieve the criterion,and Xiangjiang River and Zijiang River can not.(3)Based on the bad results of Xiangjiang Basin,the water demand of different departments in 2020 and 2030 are predicted by using the method of index analysis.And the water supply under the guaranteed rate of 25%,50%,75%in 2020 and 2030 are calculated,according to the water supply for many years.The forecast of water supply and water demand can be contribute to analyse the supply and demand balance of water resources.(4)Study on allocation of water resources according to the balance between water supply and water demand in Xiangjiang basin,the results show that water resources is more than enough under the guaranteed rate of 25%,50%in 2020 and 2030,while water shortage is96.16 million m~3and 104.37 millionm~3 under the guaranteed rate of 75%in 2020 and 2030,respectively.Based on the analysis of ecological water requirement,water quality and water quantity,it is concluded that the water shortage is not scarcity of water resources,but in quality.Finally,this article puts forward several prevention and control measures for it.