Multi-Scale Evaluation Model Of Water And Soil Environmental Quality In Watershed Ecological Restoration Project And Its Application

Based on the integrated protection and restoration project of the Liaohe River Basin(Huntai Water system),this paper established a water quality evaluation model combining hierarchical clustering and water quality identification index based on the on-site soil and water environment survey and monitoring data of sub-projects,ecological restoration units and watershed before and after the implementation of the project.A soil quality evaluation model combining single factor index method,compound index method and potential ecological risk index method was established.The comprehensive index method and the comprehensive evaluation model of water and soil improvement rate were established to carry out multi-scale evaluation of water and soil environmental quality in Fushun Section of the upper reaches of Huntai Basin.The specific research results are as follows:(1)Compared with the water environment before restoration,the water quality of five monitoring sites in the Haixin River treatment project,a tributary of Hunhe River around the subsidence area,improved,and one monitoring site had no change;In the Dahuofang Reservoir water environment protection and water purification wetland project,the water quality of 2 monitoring sites improved,and4 monitoring sites did not change;The water quality categories of the four monitoring sites in the upstream water source fence protection and ecological bank protection project of Dahuofang Reservoir were improved.Class II water quality was added to mine ecological restoration units in open-pit mines and surrounding areas,the proportion of Class III water quality increased,and the proportion of class IV water quality decreased,and the water quality improved.Class II water quality was added to the unit of forest ecological restoration and water environment management in Hunhe River Basin,and the proportion of Class III and Class IV water quality decreased,and the water quality improved.At the watershed scale,Class II water quality was newly added in Fushun Section of the upper reaches of Huntai Water system,while the proportion of Class III and Class IV water quality decreased,and the overall water quality was improved.(2)Compared with the soil environment before restoration,there are no warning and risk elements in the ecological restoration projects of the eastern and western open-pit mines and surrounding mine closures at the subproject scale;A new point of lead in the comprehensive improvement project of land in the dump and subsidence area is in alert.In the rural land comprehensive consolidation project in Hunhe River Basin,8 risk points and 5 risk elements were reduced,the types of compound risks were reduced,and the grade of compound risks was reduced.Two new lead warning points were added to the ecological restoration units of the open-pit mines and the surrounding areas.In the unit of forest ecological restoration and water environment management in Hunhe River Basin,31 risk points and 4 risk elements were reduced,the types of complex risks were reduced,and the level of complex risks did not change.At the watershed scale,31 risk points and 4 risk elements were reduced in the middle and upper reaches of Fushun section,the types of complex risks were reduced,and the level of complex risks was increased by 4.In general,the risk points decreased,the types of compound risks decreased,the proportion of clean areas increased,the proportion of warning and mild risk areas decreased,and the soil environmental quality improved.The comprehensive potential ecological risks before and after the restoration of agricultural land and construction land belong to slight ecological hazards.(3)Compared with the comprehensive water and soil environment before restoration,the scores of 3 indexes in the water environment decreased,the scores of 11 indexes increased,and the comprehensive scores increased.The water quality improvement rate was rated as low,and the water environment quality improved.The overall score of agricultural land was improved,and the improvement rate of soil environmental quality was rated as higher.The comprehensive score of construction land increased,and the improvement rate of soil environmental quality was rated as low.The score of three indexes of comprehensive soil decreased,the score of five indexes increased,and the overall score increased.The improvement rate of soil and water quality was rated as low,and the soil environmental quality improved.The comprehensive score of water and soil environment was improved,the comprehensive improvement rate was rated as low,and the overall water and soil environment was improved.