Systematic protection and restoration of water bodies in collapse areas based on surface runoff regulation

In order to solve the problems of surface runoff disorder, poor water connectivity, and weak hydrodynamic water circulation capacity in high groundwater level mining areas in the east, and to reduce the non-point source pollution and point source pollution caused by agricultural and industrial production spaces around a large number of collapsed water bodies entering the water bodies of collapsed areas through surface runoff, which leads to water quality degradation and water ecological environment risks, this paper innovatively proposes a new technology for the systematic protection and restoration of water bodies in coal mining collapsed areas and the health of the ecological system in collapsed areas through a systematic protection and restoration approach. Based on the concept of systematic protection and restoration of mountains, rivers, forests, fields, lakes, grasses, and sands, the optimization of landscape patterns in key areas, and the principle of systematic regulation of surface runoff, a new technology for the systematic protection and restoration of water bodies in collapsed areas combining "connectivity+pollution interception" is proposed. The main technical contents include: Analysis of surface runoff network using precision DEM Various water body identification and precise monitoring of water surface elevation, construction of water connected corridor network and evaluation of hydrodynamic enhancement effect, calculation of suitable range of water vegetation buffer zone, spatial identification of missing vegetation buffer zone, evaluation of water protection and restoration effect, and other technical aspects. This article takes the Yanzhou mining area in Shandong Province as an example to conduct simulation analysis on the application of systematic protection and restoration technology for collapsed water bodies based on surface runoff regulation. The results show that: ① by building water connection corridors at key locations and using hydrodynamic enhancement technology based on water connection, 45 ecological source areas were effectively connected. After connection, the maximum connection distance from east to west in the study area increased by 5 times, and the overall connectivity of the watershed was improved. The average water velocity in the corridors reached 0.067m/s, significantly improving the hydrodynamic conditions in the mining area; ② By using the pollutant interception technology based on the spatial optimization layout of vegetation buffer zones in key areas, with water connected corridors and ecological source areas as key areas, the Phillips hydrological model was used to calculate that the required vegetation buffer zone width in the Yanzhou mining area is mainly concentrated between 15-35m, with a total area of 5.59 km, of which .18 km2 is already covered by vegetation and .41 km2 is missing vegetation buffer zone to be constructed; ③ The results of SWAT scenario simulation analysis further verified that the model has a significant effect on the protection and restoration of water bodies in mining areas. Through this model, pollution can be reduced by at least 10.14% ～15.5%, and the removal effect of phosphorus element is particularly significant. The systematic protection and restoration technology proposed in this article for coal mine subsidence areas is a typical combination of landscape ecology and ecological hydrology in the ecological protection and restoration of mining areas. It has important reference value for other types of areas to achieve regional systematic protection and restoration through surface runoff regulation.