Assessment Of Water Conservation Capacity And Delineation Of Ecological Red Line Of Mineral Water In Antu County

Antu County is located in Changbai Mountain Nature Reserve,with high quality natural mineral water resources,is a rare mineral water resources gathering place in China.In recent years,well-known mineral water enterprises such as Uni-President,Evergrande Group,Nongshim and Yili have settled in Antu County.Mineral water industry has become a pillar industry of local social and economic development.In order to achieve sustainable utilization under the premise of ensuring ecological security,it is necessary to carry out systematic research on the supply source and formation process of mineral water resources.In this paper,the geo-statistical analysis software and isotope technology are combined to carry out the spatial and temporal characteristics analysis of mineral water chemistry and typical components,calculate the formation time of mineral resources,determine the supply source and restore its formation mechanism.Based on InVEST model and geographic information system（GIS）,the interannual variation,spatial and temporal distribution of water conservation capacity and its relationship with land use types in Andu area were studied.The analytic hierarchy process（AHP）is used to construct the evaluation index system of the importance of water conservation.The water conservation capacity level and the importance level of water conservation capacity are superimposed to delineate the water conservation type zoning and delineate the ecological protection red line of water conservation.The results are as follows:（1）Through water chemistry and isotope analysis,the chemical types of mineral water in Antu County are mainly HCO₃-Ca-Na type water and HCO₃-Ca-Mg type;the formation time is 27.7–77.8 a,with an average of 39.8 a.The recharge elevation is998-1467 m and the recharge sources are atmospheric precipitation and condensed water.The metasilicate component is the main water-bearing medium in the study area where groundwater is continuously dissolved.During the close contact between groundwater and surrounding rock（water-bearing medium）,the soluble SiO₂ of silicate rock is continuously dissolved through the interaction of water and rock,and the metasilicate component is formed.Deep confined groundwater gushes up along the water flowing fracture,CO₂ solubility decreases during the process,and escapes from the water in free form to form’gas bearing mineral spring’.（2）Through the InVEST model simulation and geographic information system operation,the average water conservation in Antu County from 1995 to 2018 was365.14 mm,365.83 mm,332.08 mm,364.27 mm,392.82 mm and 444.24 mm,respectively.According to the water conservation per unit area of land use types,woodland and grassland contribute the most;According to the township administrative divisions,Erdaobaihe Town contributed the most,followed by Xinhe Town and Songjiang Town.The average water conservation in the mineral spring concentrated distribution area from 1995 to 2018 was 459.37 mm,402.79 mm,428.32 mm,446.25mm,447.28 mm and 499.28 mm,respectively,which was significantly higher than the average level of Andu County.（3）According to the analytic hierarchy process（AHP）,the evaluation index system of water conservation importance is established.The main factors include precipitation P,evapotranspiration Ep,digital elevation DEM and land use types.After the data are standardized,the judgment matrix is constructed to solve the weight of each factor,and the calculation formula of water conservation importance evaluation index is obtained.Finally,the importance of water conservation in Antu County was divided into five categories,namely general importance,comparative importance,moderate importance,high importance and extremely important,which were 18.26%,19.02%,21.82%,22.79%and 18.11%,respectively.（4）Using geographic information system software ArcGIS,the water conservation capacity is divided into low,low,medium,high and high by natural discontinuity classification method.The water conservation capacity level and importance level are superimposed to obtain 25 water conservation types.The red line of water conservation ecological protection is mainly distributed in the south-central of Erdaobaihe Town,the southeast of Songjiang Town,and the east of Yongqing Town,which includes the mineral spring supply area,and can effectively ensure the water conservation of mineral springs.