Study On The Protection Of River Ecological Base Flow In Guanzhong Section Of Weihe River Mainstream

In order to scientifically coordinate the contradiction between river diversion and ecological base flow in water shortage areas and promote th,e development of ecological base flow protection,taking the guanzhong section of the Weihe River mainstream as an example,this paper focuses on the degree of ecological base flow protection;the loss of agriculture caused by ecological base flow protection,and the ecological base flow value after ensuring;and the sustainable protection of ecological base flow measures.The main research results are as follows:(1)This section analyzes the ecological base flow target values of each section of the Guanzhong section of the Weihe River.Focusing on the ecological base flow guarantee rate and the maximum regulation value of the Linjia Village section of Baoji section of the Weihe River with serious shortage of ecological base flow.The ecological base flow water shortage under the target guarantee value is calculated.The results show:①The sections of Weijiabao,Xianyang,Linyi and Huaxian can meet the requirements of ecological base flow protection value,while the shortage of ecological base flow in Linjiacun section is serious.②As the frequency of incoming water increases,the overall rate of ecological base flow protection decreases.Before and after the project diversion,the maximum regulation value of the ecological base flow in the Linjia Village section of the Baoji section of the Weihe River is quite different.The water diversion outside the channel has a s.ignificant impact on the river flow,and reducing the water diversion to improve the guarantee rate of the ecological base flow has certain feasibility.③There are different degrees of water shortage in the ecological base flow of Linjia Village section of Baoji section in different years,especially in the non-flood periods when the ecological base flow needs to be guaranteed.(2)Based on the calculation of the amount of water diversion outside the river,the Jensen model of crop growth and the calculation model of social security loss were used to calculate the direct loss and indirect loss of agricultural production in Baojixia Irrigation District after the guarantee of base flow,the change of the guarantee rate before and after the protection,and the value of base flow after guaranteed.The results show:①The upper and lower limits of direct agricultural losses in typical years are 661 million yuan and 104 million yuan respectively.The upper and lower limits of the average annual direct loss are 397 million yuan and 251 million yuan respectively.The upper and lower limits of indirect total losses in typical years are 420 million yuan and 122 million yuan,respectively.The upper and lower average annual indirect losses are 328 million yuan and 135 million yuan respectively.The amount of loss caused by the river ecological base flow protection increases with the increasing of the guarantee value.②After the implementation of the ecological base flow protection measures,the river ecological base flow protection rate has significantly improved,and the ecological base flow protection effect is remarkable.③As the value of ecological base flow regulation increases,its value increases.The social and ecological benefits brought by ensuring the ecological flow of rivers are far greater than the losses caused by them.Keeping the water filled in the river is conducive to restoring and maintaining a healthy river ecosystem,and taking full advantage of the functions of the river.④The minimum limited flow of the Linjiacun section is 5 m3/s,the maximum regulation value of the base flow in the normal year and the dry year can be controlled to 10 m3/s,while the maximum regulation value of the extremely dry year can be controlled to 9 m3/s.The ecological benefits and economic development are negatively correlated,so the decision-making department can set the ecological base flow regulation value according to the ecological health status of the river or the expected ecological base flow value and the economic loss that can be expected.The Baojixia Irrigation District bears important food supply tasks.In the actual guarantee process,factors such as food security should be considered.If necessary,the regulation value can be appropriately adjusted or lowered.(3)According to the water use situation of Baojixia Irrigation District and Guanzhong City,the ecological base flow sustainable guarantee measures are proposed.The results show:①In terms of agricultural water saving,the upper and lower limits of water saving in the recent planning level of Baojixia Irrigation District are 104 million m3 and 418 million m3 respectively,the upper and lower limits of water saving under the long-term planning level are 223 million 11m3 and 490 million 11m3 respectively.②In terms of industrial water saving,Guanzhong City,Xi’an,Xianyang and Weinan have the greatest water saving potential.In the planning level,the amount of industrial water saving is 293 million m3.(3)In terms of water saving in life.The main factors affecting the water saving situation of households are:the concern degree on household water fees,occupation and education level of residents.The main factors affecting the water saving situation in the public areas of the residents are:the publicity of water saving in the area where the residents live,the shortage of water resources,occupation,and the level of education of residents.Therefore,we should increase the propaganda of water conservation,comprehensively promote the implementation of the ladder water price system,improve the water delivery efficiency of the water supply network,and promote the reuse of water reuse technology to promote life and water conservation.④The compensation subject is the Shaanxi Provincial Government,Baoji and Xianyang Municipal Governments.The compensation object is the farmers of Baojixia Irrigation District and Weijiapu Power Station.Compensation methods usually include financial compensation,physical compensation,policy compensation and technical compensation.⑤Joint operation of reservoirs,water transfer across river basins and strict control of water diversion power generation are all effective ways to achieve sustainable protection of ecological base flows.