A method for ecological geological environment restoration level zoning in ecologically fragile mining areas

Abstract

The present invention relates to a method for classifying and zoning the ecological geological environment restoration levels in ecologically fragile mining areas, comprising the following steps: determining the total ecological water demand before and after coal seam mining according to the ecological water demand of vegetation, the water surface evaporation of surface water areas, and the evaporation of underground phreatic water; obtaining the change in ecological water demand before and after coal seam mining based on the total ecological water demand before and after coal seam mining, determining the ecological water shortage status in the mining area and conducting zoning; obtaining the landscape pattern indices before and after mining in the mining area; determining the ecological risk status in the mining area and conducting zoning according to the changes in the landscape pattern indices before and after mining in the mining area; determining and zoning the ecological geological environment restoration levels in ecologically fragile mining areas based on the zoning of the water shortage status and the zoning of the ecological risk status. Using the method of the present invention can effectively improve the accuracy of the delineation range of the ecological geological environment restoration levels in mining areas, providing a theoretical reference for the decision-making on the protection and restoration of the ecological geological environment in ecologically fragile mining areas.

Description

Technical Field

[0001] The present invention relates to the technical field of mine ecological geological environment protection and restoration, and particularly relates to a method for zoning the restoration grades of the ecological geological environment in ecologically fragile mining areas. Background Art

[0002] The statements herein only provide background art related to the present invention and do not necessarily constitute prior art.

[0003] With the large-scale development of coal resources and the continuous expansion of the scale, due to the shallow burial depth and large thickness of coal seams, the contradiction between the rich coal resources and the fragile ecological geological environment in the western mining areas has become increasingly prominent and serious, causing ecological geological environment damage problems such as surface subsidence, surface landscape damage, reduction of biodiversity, decline of the underground water table, river valley interruption, withering and death of vegetation, and aggravation of desertification. Among them, the most prominent problems are the lack of ecological water in the mining area and the fragmentation of the landscape pattern, which have had an important impact on the regional economic and social development. Therefore, proposing the restoration grades of the ecological geological environment in ecologically fragile mining areas and zoning them has important significance for the restoration of environmental problems and the sustainable economic development in ecologically fragile mining areas.

[0004] At present, for the research on the determination and zoning method of the restoration grades of the ecological geological environment in mining areas, mathematical theory evaluation methods are often adopted, such as the fuzzy Delphi analytic hierarchy process, the weighted fuzzy C-means clustering method, etc. For example, patents CN201910187343.6 and CN201810089353.1. However, there is no report on the method for restoring the ecological geological environment in ecologically fragile mining areas from the perspectives of ecological water shortage and landscape pattern in the mining area. If the prominent problems such as ecological water shortage and landscape pattern in the mining area are ignored, it will cause problems such as unclear zoning of the restoration grades of the ecological geological environment, being affected by objective factors, and low accuracy in delineating the ranges of different grades, making it difficult to provide a solid scientific basis for the method of restoring the ecological geological environment in the mining area and even greatly increasing the cost of restoring the ecological geological environment. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art, and provides a method for zoning the restoration grades of the ecological geological environment in ecologically fragile mining areas, to solve the related problems such as unclear zoning of the restoration grades of the ecological geological environment in ecologically fragile mining areas, being affected by objective factors, and low accuracy in delineating the ranges of different grades, and to provide a theoretical reference basis for restoring the ecological geological environment in ecologically fragile mining areas.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions

[0007] An embodiment of the present invention provides a method for zoning the restoration grades of the ecological geological environment in ecologically fragile mining areas, including the following steps:

[0008] The total ecological water demand before and after coal mining is determined based on the ecological water demand of vegetation, surface evaporation of surface waters and underground phreatic water evaporation;

[0009] According to the total ecological water demand before and after coal seam mining, the change of ecological water demand before and after coal seam mining is obtained, and the ecological water shortage status of the mining area is determined and divided into zones;

[0010] Obtain the landscape pattern index before and after mining in the mining area;

[0011] Determine the ecological risk status of the mining area and divide it into different zones according to the changes in the landscape pattern index before and after mining;

[0012] The ecological geological environment restoration level zoning of ecologically fragile mining areas is determined based on the zoning of water shortage status and ecological risk status.

[0013] Alternatively, the method for obtaining the ecological water demand of vegetation is as follows: the NDVI distribution of the mining area before and after coal mining is obtained in advance, and based on the ecological water demand quota method and combined with ArcGIS spatial analysis, the spatial distribution of the ecological water demand quota of vegetation before and after mining and the ecological water demand of vegetation are obtained.

[0014] Optionally, the method for obtaining the surface evaporation of the surface water area is: determine the area of the surface water area before and after mining in the mining area, and obtain the surface evaporation of the surface water area in the mining area before and after coal seam mining in combination with the previously obtained surface evaporation of the mining area.

[0015] Optionally, the method for obtaining underground groundwater evaporation is:

[0016] Obtain post-mining groundwater level;

[0017] The underground phreatic water evaporation is obtained according to the underground phreatic water level and the pre-acquired water surface evaporation.

[0018] Optionally, the specific method for obtaining the groundwater level after mining is as follows:

[0019] Combined with the pre-acquired hydrogeological conditions of the rock formations containing / isolating water and the surface elevation of the mining area, the numerical simulation boundary conditions, parameter partitioning, grid division, and source and sink assignment are determined to establish a three-dimensional hydrogeological numerical model of the mining area;

[0020] The established three-dimensional hydrogeological numerical model of the mining area is used to set the hydrogeological parameters of the overburden aquifer and aquiclude to simulate and reproduce the underground water level after mining.

[0021] Optionally, the feasibility of the three-dimensional hydrogeological numerical model of the mining area is verified by trial calculation using the measured points of the groundwater level. If it is not feasible, the three-dimensional hydrogeological numerical model of the mining area is adjusted.

[0022] Optionally, the change in ecological water demand before and after coal seam mining is the total ecological water demand after mining minus the total ecological water demand before mining. If the difference is negative, it indicates a water shortage situation; otherwise, it means there is no water shortage.

[0023] Optionally, the landscape pattern indices before and after mining include the landscape shape index, landscape patch density, largest patch index, Shannon diversity index, proportion of the largest patch in the landscape area, and landscape fragmentation index before and after mining in the mining area.

[0024] Optionally, for the same landscape pattern index, compare the evolution and distribution law of its value before and after coal seam mining; respectively compare multiple landscape pattern indices before and after mining in the mining area, and combine the spatial analysis function of ArcGIS and the ecological significance of landscape pattern indices to determine the ecological risk status of the mining area and divide it into zones.

[0025] Optionally, when the ecological risk is high and in a water shortage state, it is regarded as an area that urgently needs artificial restoration; when the ecological risk is high and in a non - water - shortage state, it is regarded as a natural restoration area; when the ecological risk is low and in a water shortage state, it is regarded as an area combining natural restoration and artificial restoration; when the ecological risk is low and in a non - water - shortage state, it is regarded as an area with no impact.

[0026] Advantages of the present invention:

[0027] The method of the present invention calculates the total ecological water demand before and after coal seam mining in the mining area from three aspects: vegetation ecological water demand, surface water evaporation, and groundwater evaporation; calculates the change in ecological water demand before and after coal seam mining in the mining area, determines the ecological water shortage status of the mining area and divides it into zones; calculates the landscape pattern indices before and after mining in the mining area respectively; compares the changes in landscape pattern indices before and after mining in the mining area to determine the ecological risk status of the mining area and divide it into zones; combines the water shortage degree of the mining area and the ecological risk zones to propose the ecological geological environment restoration grades and zoning for ecologically fragile mining areas. Considering the prominent problems of ecological water shortage and landscape pattern in the mining area, this method has clear basis, is simple and easy to implement, can effectively improve the accuracy of the delineation range of the ecological geological environment restoration grade in the mining area, and provides a theoretical reference for the decision - making of ecological geological environment protection and restoration in ecologically fragile mining areas. Description of the Drawings

[0028] The specification drawings forming a part of this application are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute a limitation to this application.

[0029] Figure 1 It is the flowchart of the method in Embodiment 1 of the present invention;

[0030] Figure 2 It is the zoning map of the ecological geological environment restoration grade of a certain mining area in the practical application of Embodiment 1 of the present invention; Detailed Embodiments

[0031] Example 1

[0032] This embodiment provides a method for zoning ecological geological environment restoration levels in ecologically fragile mining areas. Figure 1 As shown, the following steps are included:

[0033] Step S1: Obtain the measured data of groundwater level in the mining area, rock formation water-bearing / water-blocking hydrogeological conditions, mining area land use type, NDVI, surface elevation, surface water area, rainfall and other data. Among them, rock formation water-bearing / water-blocking hydrogeological conditions refer to: mining area rock formation structure, aquifer permeability, water supply, boundary conditions, hydraulic characteristics and recharge and discharge conditions; obtain the land use type, NDVI, surface elevation and surface water area (mainly rivers and lakes) before and after coal mining in the mining area based on remote sensing data; obtain the multi-year average rainfall based on the data of meteorological stations around the mining area.

[0034] Step S2: Establish a three-dimensional hydrogeological numerical model of the mining area to simulate and reproduce the underground water level.

[0035] Step S2 specifically includes the following steps:

[0036] Step S21. Combined with the hydrogeological conditions of the rock formation containing / isolating water and the surface elevation of the mining area obtained in step S1, determine the numerical simulation boundary conditions, parameter partitioning, grid division, assign source and sink items, and establish a three-dimensional hydrogeological numerical model of the mining area;

[0037] Step S22: adopt trial calculation means and use the actual groundwater level measurement points to identify and verify the feasibility of the three-dimensional hydrogeological numerical model of the mining area. If it is not feasible, adjust the three-dimensional hydrogeological numerical model of the mining area. By adjusting parameter partitioning, grid division and other means, adjust the three-dimensional hydrogeological vertical model until the requirements are met.

[0038] Step S23: using the constructed three-dimensional hydrogeological numerical model of the mining area, according to the mining conditions, taking into account factors such as rainfall, the hydrogeological parameters of the overburden aquifer and the aquiclude are set to simulate and reproduce the underground water level after mining.

[0039] Step S3: Calculate the total ecological water demand before and after coal seam mining in the mining area from three aspects: vegetation ecological water demand, surface evaporation of surface waters, and underground groundwater evaporation. The steps are as follows:

[0040] Step S31: Calculate the ecological water demand of vegetation: Based on the NDVI distribution of the mining area before and after coal mining obtained in step S1, based on the ecological water demand quota method (commonly used Penman-Monteith formula, formula 1), combined with ArcGIS spatial analysis function, obtain the spatial distribution of the ecological water demand quota of vegetation before and after mining in the mining area and the ecological water demand of vegetation;

[0041] Q e,q = K S × K q × Q e,0 (1)

[0042] In the formula, Q e,q is the vegetation ecological water requirement quota, in mm; K q is the proportionality coefficient of the maximum water requirement and potential water consumption of vegetation, that is, the vegetation ecological water consumption coefficient; K S is the soil moisture regulation coefficient; Q e,0 is the potential evapotranspiration of vegetation, in mm.

[0043] Step S32: Calculate the water surface evaporation of surface water areas: Considering that most of the ecologically fragile mining areas are in arid and semi-arid regions, mainly calculate the surface water evaporation during the wet season (from June to September), that is: Use remote sensing monitoring technology to determine the areas of surface water areas, namely rivers and lakes, before and after mining in the mining area respectively, and combine the water surface evaporation of the existing data obtained in advance in this area to calculate the evaporation of surface water areas of rivers and lakes in the mining area before and after coal seam mining, that is, the water surface evaporation of surface water areas, as shown in Formula 2;

[0044] W = A × E0 (2)

[0045] In the formula, W is the water surface evaporation of surface water areas, in mm; A is the area of surface water areas, in m 2 ; E0 is the water surface evaporation, in mm.

[0046] Step S33: Calculate the phreatic evaporation: Based on the Avetianov phreatic evaporation model formula (Formula 3), combined with the numerical simulation values of the phreatic water level in Step S2, calculate the phreatic evaporation in the mining area before and after coal seam mining respectively

[0047] E = a × (1 - H / H max ) b × E0 (3)

[0048] In the formula, E is the phreatic evaporation, in mm; H is the phreatic water level, in m; H max is the buried depth of the phreatic water level at which evaporation stops, in m; H max is between 1.5 - 4.0 m; E0 is the water surface evaporation, in mm; a, b are undetermined coefficients related to vegetation.

[0049] Step S34. Calculate the vegetation ecological water requirements, water surface evaporation of surface water areas, and phreatic evaporation in the mining area before and after coal seam mining respectively, and generate thematic maps of the total ecological water requirement distribution before and after coal seam mining based on ArcGIS.

[0050] Step S4: Calculate the change in ecological water demand before and after coal seam mining in the mining area, determine the ecological water shortage status of the mining area and divide it into zones. The specific process is as follows: Obtain the above-mentioned thematic maps of vegetation ecological water demand, surface water evaporation in surface water areas, and phreatic evaporation respectively. Through the spatial analysis function of ArcGIS, overlay the three thematic maps to obtain the total ecological water demand before and after coal seam mining. Subtract the total ecological water demand before mining from the total ecological water demand after mining to obtain the thematic map of the ecological water shortage status of the mining area. If the difference between the two is negative, it indicates a water shortage status; otherwise, it is a non-water shortage status. When the difference is zero, the total ecological water demand before and after mining in the mining area remains unchanged, and it can be classified as a non-ecological water shortage status.

[0051] Step S5. Calculate the landscape pattern indices before and after coal seam mining in the mining area respectively. The specific process is as follows: Based on obtaining the land use types in the mining area before and after coal seam mining, calculate six landscape pattern indices including landscape shape index, landscape patch density, largest patch index, Shannon diversity index, proportion of the largest patch in the landscape area, and landscape division index before and after mining respectively based on Fragstats, and generate 12 corresponding thematic maps based on ArcGIS.

[0052] Step S6: Compare the changes in landscape pattern indices before and after coal seam mining in the mining area, determine the ecological risk status of the mining area and divide it into zones. The specific process is as follows: For the same landscape pattern index, compare the evolution and distribution law of its value before and after coal seam mining; compare the six landscape pattern indices before and after coal seam mining in the mining area respectively, and combine the spatial analysis function of ArcGIS and the ecological significance of landscape pattern indices to determine the ecological risk status of the mining area and divide it into zones.

[0053] Step S7: Combine the water shortage degree of the mining area and the ecological risk zones, and propose the ecological geological environment restoration grades and zoning for the ecologically fragile mining area. The specific process is as follows: Combine the water shortage degree of the mining area and the ecological risk zones, and propose four ecological geological environment restoration grades for the ecologically fragile mining area: urgent need for artificial restoration, natural restoration + artificial restoration, natural restoration, and no-impact area; Based on the spatial analysis function of ArcGIS, according to the following combinations of water shortage and ecological risk zones: When the ecological risk is high and in a water shortage state, it is an area urgently in need of artificial restoration. When the ecological risk is high and in a non-water shortage state, it is a natural restoration area. When the ecological risk is low and in a water shortage state, it is an area combining natural restoration and artificial restoration. When the ecological risk is low and in a non-water shortage state, it is a no-impact area.

[0054] Using the method of this embodiment to zone the ecological geological environment protection grades of ecologically fragile mining areas, the applications in actual projects include: (1) providing a scientific basis for the selection of ecological geological environment protection and restoration methods in different areas of the mining area; (2) being able to plan the mining area in advance and guide coal mining production; (3) formulating restoration plans according to different ecological geological environment restoration grades.

[0055] In a practical application of the method of this embodiment:

[0056] A certain mining area is located in an arid - semi - arid region with scarce water resources and a fragile ecological geological environment, belonging to an ecologically fragile mining area. The shallow - layer groundwater in the Quaternary system is an important factor in maintaining the surface ecological environment. After coal seam mining, the groundwater level drops, the surface water area changes, the growth of vegetation is stressed, and it is easy to induce changes in the ecological water demand and landscape pattern in the mining area, causing varying degrees of damage to the ecological geological environment.

[0057] Accordingly, according to the steps of a method for zoning the ecological geological environment restoration level in an ecologically fragile mining area, the ecological geological environment restoration level of this ecologically fragile mining area is zoned, as Figure 2 shown. In addition, different surface areas are investigated to verify the accuracy of this method.

[0058] Facts have proved that this method not only has good practicability, but also has clear basis and is simple and easy to implement. It can effectively improve the accuracy of delineating the scope of the ecological geological environment restoration level area in an ecologically fragile mining area, providing a theoretical reference for the protection and restoration of the ecological geological environment in the mining area.

[0059] Although the specific implementation manners of the present invention are described above in conjunction with the accompanying drawings, it is not a limitation to the protection scope of the present invention. Those skilled in the art should understand that based on the technical solutions of the present invention, various modifications or deformations that can be made without creative efforts by those skilled in the art are still within the protection scope of the present invention.

Claims

1. A method for ecological geological environment restoration grade zoning in ecologically fragile mining areas, characterized in that, The following steps are involved: The total ecological water demand before and after coal mining is determined based on the ecological water demand of vegetation, surface evaporation of surface waters and underground phreatic water evaporation; According to the total ecological water demand before and after coal seam mining, the change of ecological water demand before and after coal seam mining is obtained, and the ecological water shortage status of the mining area is determined and divided into zones; Obtain the landscape pattern index before and after mining in the mining area; Determine the ecological risk status of the mining area and divide it into different zones according to the changes in the landscape pattern index before and after mining; Determine the ecological geological environment restoration level and zoning of ecologically fragile mining areas according to the zoning of water shortage status and ecological risk status; The method for obtaining the ecological water demand of vegetation is as follows: the NDVI distribution of the mining area before and after coal mining is obtained in advance, and based on the ecological water demand quota method, combined with ArcGIS spatial analysis, the spatial distribution of the ecological water demand quota of vegetation before and after mining and the ecological water demand of vegetation are obtained; The method for obtaining the evaporation of the surface water area is as follows: determine the area of the surface water area before and after mining in the mining area respectively, and obtain the evaporation of the surface water area before and after coal seam mining by combining the previously obtained evaporation of the surface water area in the mining area; The method for obtaining underground groundwater evaporation is: Obtain the underground water level after mining; obtain the underground water evaporation according to the underground water level and the pre-obtained water surface evaporation; The landscape pattern index before and after mining includes the mining area landscape shape index before and after mining, landscape patch density, maximum patch index, Shannon diversity index, the proportion of the largest patch in the landscape area, and landscape segmentation index; For the same landscape pattern index, the value evolution and distribution law before and after coal seam mining are compared; various landscape pattern indices before and after mining in the mining area are compared respectively, and the ecological risk status of the mining area is determined and zoned by combining the ArcGIS spatial analysis function and the ecological significance of the landscape pattern index.

2. The ecological geological environment restoration grade zoning method for an ecologically fragile mining area according to claim 1, wherein, Specific methods for obtaining the groundwater level after mining: Combined with the pre-acquired hydrogeological conditions of the rock formations containing / isolating water and the surface elevation of the mining area, the numerical simulation boundary conditions, parameter partitioning, grid division, and source and sink assignment are determined to establish a three-dimensional hydrogeological numerical model of the mining area; The established three-dimensional hydrogeological numerical model of the mining area is used to set the hydrogeological parameters of the overburden aquifer and aquiclude to simulate and reproduce the underground water level after mining.

3. The ecological geological environment restoration grade zoning method for an ecologically fragile mining area as described in claim 2, wherein Using the measured points of groundwater level, trial calculations are used to verify the feasibility of the three-dimensional hydrogeological numerical model of the mining area. If it is not feasible, the three-dimensional hydrogeological numerical model of the mining area is adjusted.

4. A method for ecological geological environment restoration grade zoning in an ecologically fragile mining area as described in claim 1, characterized in that, The change in ecological water demand before and after coal mining is the total ecological water demand after mining minus the total ecological water demand before mining. If the difference is negative, the surface is in a water-scarce state, otherwise it is not in a water-scarce state.

5. The ecological geological environment restoration grade zoning method for an ecologically fragile mining area according to claim 1, characterized in that, When the ecological risk is high and the state is water-scarce, it is regarded as an area in urgent need of artificial restoration; when the ecological risk is high and there is no water shortage, it is regarded as a natural recovery area; when the ecological risk is low and there is a water shortage, it is regarded as an area combining natural and artificial restoration; when the ecological risk is low and there is no water shortage, it is regarded as a no-impact area.

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