Optimal Allocation Of Water Resources Based On The Ecological Water Demand And Eco-compensation In Lake Dianchi Basin

Water resources are important for survival and development of human being.Nowadays,the water crisis has become a worldwide problem due to the unreasonable utilization of water resources and the aggravation of environmental pollution.Lake Dianchi Basin is located in Kunming City,Yunnan Province,economic and social water use for a long time squeezes ecological water,resulting in serious shortage of water for rivers and lakes in the basin,the contradiction in water use is very prominent.In order to alleviate the pressure of water use and improve the quality of water in the Lake Dianchi Basin,the Kunming Municipal Government has implemented a number of water diversion projects to provide water for the Lake Dianchi Basin.This study explored the ecological water demand of the lake-rivers coupled ecosystem based on the water volume relationship and water quality relationship between rivers and lakes.The economic valuation techniques were adopted in this study to evaluate the ecosystem service value and economic loss before and after the construction of water diversion project in Niulanjiang River Basin,and based on this,the eco-compensation of the Niulanjiang River diversion project was determined.Finally,based on ecological water use of rivers-lake coupled ecosystem and eco-compensation,the allocation of available water resources in the Lake Dianchi Basin were optimized to provide reference for water resources planning and water allocation.The main results are as follows:(1)The ecological water demand of rivers-lake coupled ecosystem is much higher than the sum of the ecological water demand of lake and rivers,and the ecological water demand cannot be met currently.Water environmental pollution seriously affects the ecological water demand in the basin,and the ecological water demand decreases exponentially with the decrease of pollution load.(2)The ecosystem service value of the Niulanjiang River Basin increased on the whole(?39.81×10~8CNY/a),but not in the upstream and downstream,and the ecosystem service value in the downstream decreased because of the loss of water volume(?3.15×10~8CNY/a).Although the value of ecosystem services in the upstream has increased,land acquisition for the construction of reservoir has caused economic losses for local residents(?0.64×10~8CNY/a).Based on the eco-compensation of the upstream and downstream of Niulanjiang River Basin,the total eco-compensation of the project is?3.79×10~8 CNY/a.(3)The results of optimized water resources allocation based on ecological water use and eco-compensation show that to ensure the water requirements of the Lake Dianchi Basin,the minimum cost is?32.96×10~8 CNY,of which the water transfer cost accounts for 99%,and the cost of reservoir water only accounts for 1%.The demand for transfer water accounts for 56%of the total water consumption,2.43 times the current designed water transfer.The utilization rate of the reservoir and the natural runoff of river is 100%,but only 19%and 24%of the total water consumption respectively.The water scarcity and poor water quality are still important issues in Lake Dianchi Basin.