Study On Optimum Layout Of Water Function Areas

In the 21 st century,with the development of society and the improvement of scientific level,the demand for water resources and the requirement of quality are also increasing.The deterioration of water environment limits the long-term development of society and increases the pressure of global water resources protection.The present situation of water pollution in China is relatively serious.A large number of polluted water is discharged into rivers,which destroys the use function of river water,reduces the efficiency of water resources and hinders the development of society."Water Function Regionalization of National Important Rivers and Lakes(2011-2030)",approved by the State in 2011,marks that the management of water resources protection in China has risen to a new height.However,in recent years,due to the rapid development of economy and the constant adjustment of urban development planning,the existing water function areas have gradually shown such problems as incomplete coverage,unreasonable function orientation,too high or too low water quality objective setting,and incoherence between upstream and downstream water quality objectives.It is urgent to optimize the layout of regional water function areas,standardize the development and utilization of water resources,and protecting water resources environment.This paper summarizes the general situation of water function areas in China,puts forward the need of optimizing the layout of water function areas,and chooses Shaying River in Huaihe River Basin as the research area,analyses the need of optimizing the layout of water function areas in Shaying River Basin,and formulates the optimizing layout scheme of water function areas in the research area.The water quality model was used to verify the pollution carrying capacity of water function areas,and the suitable calculation method of ecological flow was selected.The control index of ecological flow was studied and formulated.The current situation of water quality and water quantity in water function area was evaluated and analyzed.The conclusions are as follows:(1)Put forward the requirement of optimizing the layout of water function areas in China,and formulate the requirements,principles and constraints of optimizing the layout of water function areas.By summarizing the general situation of water function areas in China,the significance and effectiveness of water function area management,the problems and shortcomings encountered in the management and practice of water function areas in China are analyzed,and the demand for optimal layout of water function areas in China is put forward.On this basis,the requirements,principles and constraints for optimal layout of water function areas are studied and formulated.(2)The optimal layout scheme of water function areas in Shaying River Basin was formulated.Based on the analysis of the present situation of water resources and water function areas in Shaying River,the optimal layout requirements of water function areas in the river basin are put forward.On the basis of the water function area criteria and the requirements,principles and constraints,the optimal layout scheme of water function areas in the river basin is formulated.(3)After optimizing the layout of water function areas,the pollution carrying capacity and the index of ecological flow control has been increased.The river water quality model was selected to verify the pollution carrying capacity of the water function area after the optimized layout,and the pollution carrying capacity of the water function areas before and after the optimized layout were compared and analyzed.The appropriate calculation method of ecological flow was selected,and the control index of ecological flow in water function areas were calculated,which ensure the basic demand of ecological flow.(4)In the current year,the amount of pollution entering the river in some water function areas is relatively large,resulting in the water quality not up to the standard and the rate of water quantity reaching the standard is low.According to the verification and calculation results of pollution carrying capacity and ecological flow in water function areas,the water quality and quantity of current annual water function areas are evaluated,due to the large amount of river-entering pollution in some water function areas in the current year,the water quality is not up to the standard.The current situation of water quantity reaching the standard in the year is not satisfactory,the rate of reaching the standard is 41.8%.