| The Xi Cao-hai Wetland(XCW)in Heqing County is one of the typical wetland types in Yunnan Plateau,and it was listed as a Dali Prefecture Nature Reserve in 2001.XCW is an important migratory habitat for migratory birds and overwintering habitat for a large number of migratory birds.It is also an important water source for agricultural irrigation in surrounding communities,which plays an vital role in maintaining biodiversity,providing water resources,adjusting regional climate,and conserving water resources.XCW can meet both irrigation and ecosystem service function at most of the time in a year,but the multiple pump stations centralized pumping from XCW every year during the transplanting and preservating rice seedlings(May to June),which has certain impact on the ecological service function of XCW.In particular,due to excessive water intaking from XCW in arid years,most of its area dried up and cracked,which severely affected its ecosystem service function.Based on the analysis of the main ecological service functions of the XCW,this paper evaluates the ecological service function of XCW by the method of environmental value evaluation.Through the field investigation of the research area to distinguish the main contradiction between wetland ecosystem function and community social production.It means that achieving the balance between the wetland ecological water demand for maintaining wetland ecosystem healthily and the water resources supply for community agricultural production activities.Using high precision terrain measurement to obtain Three-dimensional terrain of XCW,construct a simplified water level-the concept of surface area-water volume model,and combine with the minimum and suitable ecological water level of XCW,to calculate the minimum wetland suitable ecological water demand.According to the demand of wetland agricultural water to design the wetlands available for agricultural water in different rain frequency scenarios.At last,the water resources control measures and the ecological compensation scheme of the control measures are put forward at different time node conflicts,and the water resource utilization optimization management mode of XCW is put forward to balance the wetland protection and the community economic development.The main conclusions are as follows:(1)According to the identification of themajorecological service function of XCW,the nine service values of the XCW ecosystem in 2015 were quantitatively evaluated,and the total value of the wetlands was 33.2031 million yuan which accounts for 0.60%of the total production value of Heqing County in the same year.The direct use value of the XCW in three aspects:material production,leisure and entertainment,education and research was 8.5737 million yuan which accounted for25.82%of the total value.The indirect use value of the XCW in three aspects:water conservation,climate regulation and biodiversity conservation was 3.5747 million yuan,which accounted for 10.77%of the total value.The non-use value of the XCW was calculated to be 21.0547 million yuan through a questionnaire survey on individual willingness to pay by the method of conditional value,which accounted for63.41%of the total value.(2)According to the years of experience in management and operation of wetland management department,combine the water level of the wetland and curve of surface area relationship to keep thewater surface elevation in central part of Xi Cao-hai is 2192.497m,which is the minimum ecological water level of the wetland.The suitable ecological water level for the XCW is 2193.189m,which is comprehensive determined by geological land-forms and restrictions on water level produced by major birds.The minimum ecological water requirement of the XCW was calculated to be 9.808×10~4m~3,and thesuitable ecological water requirement was58.265×10~4m~3 by the method of ecological water level to calculate the ecological water requirement.(3)Through the investigation and analysis of wetland agricultural water conditions,it was calculated that the amount of water pumped from the Xi Cao-hai for irrigation is 242.64×10~4m~3 each year,of which transplanting and preservatingrice seedlings are centralized in May to June each year,and a total of 162.55×10~4m~3 of water was pumped away.Five differentrain frequency scenarios are selected during the key water using:P=10%,P=25%,P=50%,P=75%,and P=90%.The amount of water available in wetlands is greater than the amount of water used in agriculture,and there is no water gap when the rain frequency P?50%.Under the condition of P=75%and P=90%rain frequency,in order to meet the minimum ecological water requirement of the XCW,the ecological water transfer volume needs to be 2.94×10~4m~3 and 54.53×10~4m~3.(4)The water resources control measures and the ecological compensation scheme of the control measures are put forward at different time node conflicts.It should meet the minimum ecological water level of the wetland during the key ecological water level in the May to June,the elevation of the water surface in central part of Xi Cao-hai is 2192.497m.It should be stopped that taking water from Xi cao-hai when the water levelbelows it,the water shortage is considered to be transferred from the Dong Cao-hai.It is suggested that suitable ecological water level in wetlands should be 2193.189m when migratory birds wintering from October to march every year.At this time,the water volume of the three water bodies is58.265×10~4m~3.It is the foundation of the protection management and scientific utilization that quantifying the ecological service value of XCW,clarifying the core conflict between the protection of the XCW and the direct utilization of the community.By comparing the ecosystem service value of the XCW with the economic value of agriculture generated by the supply of water resources,we can know that priority should be given to ensuring the ecological water demand of wetlands In the face of conflicts of water resources utilization,and then maintain the health of wetland ecosystems.It provides a quantitative basis that to balance the contradiction between the service function of"water resources regulation and supply"and the service function of wetland ecosystem services simultaneously. |
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