Study On Calculation Method And Protection Compensation Mechanism Of The River Ecological Base Flow

Facing the actual situation of water environment deterioration,cut-off and shrinking of rivers in water shortage areas,it is urgent to focus on the protection of river ecological base flow,so as to promote the restoration of river water ecological health in water shortage areas.Protection of base flow is the key to the restoration of river water ecological environment.However,there are still some deficiencies in research on calculation method,compensation mechanism and compensation fund sharing of protection of river ecological base flow,which urgently need further research.According to characteristics of typical rivers in water shortage areas,four calculation methods of river ecological base flow were established.Compensation model of protection of the ecological base flow was established;Fund sharing model of main body of protection compensation of river ecological base flow was established.Compensation mechanism of river ecological base flow was constructed.Taking Baoji section of Weihe River as an example,the main results are as follows:(1)Through empirical formula method,hydraulics and one-dimensional water quality model,the ecological flow velocity for maintaining the balance of flow and sediment,protecting aquatic biodiversity and purifying water quality were calculated,respectively.Combined with above three ecological flow velocity,a coupling ecological flow velocity which can meet the three ecological protection objectives at the same time was determined.Combined with above ecological velocity and the hydraulic relation of river section,we established the calculation method of the ecological base flow of rivers.Taking Baoji section of the Weihe River as an example,the results show that:l)The range of coupling ecological flow velocity in non-flood season is[0.39,0.46m/s],and 0.80 m/s is the bottom limit in flood season.2)The river ecological base flow in non-flood season is[5.66,7.42 m3/s]and 21.69 m3/s is the bottom limit in flood season,respectively.3)From 2000 to 2015,the average protection rate of ecological base flow was 28.95%,which could not meet the standard required buy the Government(90%).(2)The river service functions was divided into economic and ecological service functions.The C-D production function and the equivalent factor method were used to calculate two service function values,and the two values are added together.When the total value reaches the maximum,the water requirement of river ecological service functions is the river ecological base flow.The agricultural economic loss of protection of river ecological base flow was calculated,which was divided into acceptable and unacceptable economic loss,and acceptable economic loss probability of different river ecological base flow was determined,combined with above acceptable economic loss of water resource managers,the calculation method of ecological base flow was established.The river system service functions was divided into economic and ecological service functions,the economic and ecological services function values were calculated.The former was regarded as the opportunity cost of the latter.Combined with maximizing the marginal benefit of ecological base flow,calculation method of river ecological base flow was established.Taking Baoji section of Weihe River as an example,the calculation results show:Based on maximization of total value of river system service functions,acceptable loss probability of the water resource decision-makers and maximum marginal benefit of ecological base flow are 35.02%,21.59%and 33.83%of runoff,respectively.(3)Based on the definition,connotation,calculation method of river ecological base flow and regional economic development,a quantitative method for determining suitable river ecological base flow was established.Based on the analysis of protection goal of river ecological base flow,the calculation model of compensation amount of protection of the river ecological base flow was proposed.Taking Baoji section of Weihe River as an example,the research results show that:1)the suitable base limit of river ecological base flow in non-flood season is 5.66 m3/s.2)Based on the input cost,compensation amount of protection of the river ecological base flow is 269 million yuan.3)The compensation amount based on the value increment of river ecological base flow is 95 million yuan.4)The big difference between the two compensation amounts is due to people's recognition of the value of base flow and external effect,in this paper,the compensation of value increment is recommended,which is in line with the current living standard.(4)The subject and object of compensation were identified by using the interest relationship of protection of river ecological base flow.Combined with advantages and disadvantages of the five compensation ways,the best compensation ways was defined.On the basis of the proportion of the ecological base flow value shared by the compensation subject and its total value,the fund sharing model of compensation subjects was established.On the basis of above compensation subject and object,compensation standard,the best compensation ways and fund sharing amount,compensation mechanism of protection of river ecological base flow was established.Taking Baoji section of Weihe River in 2010 as an example,the research results show that:1)the subjects of compensation are Shaanxi Province,Baoji City,Xianyang City,Xi'an City and Weinan City,and the objects of compensation are damaged farmers and irrigation district administration;2)The best combination of the intelligence compensation and project compensation is the best compensation ways;3)Fund sharing coefficient of compensation subjects are 70.81%,22.84%and 6.35%.Funds sharing of compensation subjects are 67,22 and 6 million yuan.