Discriminating method for elevation interval of topographic reconstruction of ecological restoration engineering of retrofit and beach returning

Abstract

The invention discloses a method for discriminating a topographic reconstruction elevation interval of a retrofit beach-returning ecological restoration project, and relates to the technical field of topographic reconstruction, and the method comprises the steps: building an elevation relation between a tidal water level and an actually measured topography of a to-be-restored region of a culture pond, and carrying out the elevation assignment of the actually measured tidal water level in a hydrological annual period range, determining a regional tide submerging elevation; determining a terrain reconstruction elevation interval of the retrofit beach restoration area through calculation of a tide water level elevation and a spatial elevation between current actual measurement terrains of a to-be-restored area of the culture pond; and according to the determined elevation transformation interval, a filling area, a bulldozing area and a reserved area of the rebay beach restoration area are defined so as to guide construction of rebay beach restoration ecological restoration engineering. By utilizing the method provided by the invention, accurate judgment of the topographic reconstruction elevation interval of the retrofit beach-returning ecological restoration area can be realized, implementation of retrofit beach-returning ecological restoration engineering is effectively guided, restoration of a water system of the retrofit beach-returning ecological restoration area is facilitated, and the ecological restoration efficiency of the coastal culture wasteland is improved.

Description

Technical Field

[0001] The invention relates to the technical field of terrain transformation, and in particular to a method for determining elevation intervals of terrain transformation in a beach ecological restoration project. Background Art

[0002] With the rapid social and economic development of coastal cities, coastal tidal flats have been continuously transformed into marine aquaculture ponds, which have seriously squeezed the coastal tidal flats, causing the shrinkage of tidal flat areas and the degradation of tidal flat water systems.

[0003] In recent years, with the continuous advancement of ecological civilization construction and the continuous implementation of coastal tidal flat ecological restoration projects, a large number of marine aquaculture ponds have been withdrawn, forming large-scale aquaculture wastelands at the front edge of coastal wetlands, which are in urgent need of ecological restoration. As the main way to restore abandoned marine aquaculture land, the implemented projects usually rely on experience to design restoration plans and engineering construction. Due to the lack of necessary scientific methods for guidance, the restoration effect is not ideal. The main reason is that the areas where restoration has been carried out have not carried out the necessary analysis of the relationship between hydrological processes and terrain. The ecological restoration project of retiring aquaculture to the beach has no clear elevation transformation threshold or interval as a guide in terrain transformation, resulting in the inability of tidal water flow to effectively reach the retiring and beach restoration area after the transformation, and the tidal water system cannot be restored, causing the vegetation landscape in the retiring and beach restoration area to recover slowly or not at all, and it is difficult to build the retiring and beach restoration area into a potential habitat for water birds.

[0004] Therefore, in view of the practical problems existing in the ecological restoration project of the abandoned land of aquaculture in coastal wetlands mentioned above, there is an urgent need for a scientific and effective method to accurately identify the elevation range of terrain transformation in the restoration area, so as to effectively carry out the basic terrain transformation of the restoration area and promote the restoration of water system and vegetation in the restoration area. Summary of the invention

[0005] The purpose of the present invention is to provide a method for determining the elevation interval of terrain transformation in a beach ecological restoration project to solve the problems raised in the background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for determining the elevation interval of terrain transformation in a beach reclamation and ecological restoration project comprises the following steps:

[0008] Step 1: Topographic data collection, obtain the topographic data of the abandoned marine aquaculture pond to be restored, and determine the surface elevation H of the beach ecological restoration area. i , where the maximum elevation is H max , the minimum elevation is H min and the average elevation is ˉH;

[0009] Step 2: Tidal water level observation: obtain the measured tidal water level L at different times according to the tidal hydrological observation equipment. i The maximum tidal level that can reach the beach restoration area is determined to be L max , the minimum tidal level is L min , the average tidal water level is Lˉ;

[0010] Step 3: Calculate the tidal inundation elevation. Based on the known bottom elevation of the tidal hydrological observation equipment installation point and the measured tidal water levels at different times, calculate the elevation range h of the beach restoration area that the tide can reach. i , where the maximum elevation is h max , the minimum elevation is h min , the average elevation is h;

[0011] Step 4: Analyze the elevation range of terrain transformation. According to the tidal water level and the measured terrain data of the proposed restoration area of ​​abandoned marine aquaculture ponds, the elevation range that can be reached by tide in the ecological restoration area of ​​the abandoned aquaculture ponds is determined as [h min ,h max ], the average elevation is hˉ, and the area below the average elevation h is the frequently flooded area. Considering that the habitat of waterbirds requires certain plant belts and high-platform habitat islands, the terrain elevation change interval of the regional reclamation and beach restoration ecological restoration project is determined to be [hˉ, h max ];

[0012] Step 5: Divide the transformation area. Based on the measured topography of the abandoned marine aquaculture pond restoration area, and using the calculated terrain transformation elevation range as the control range, transform the abandoned aquaculture pond restoration area into a nearly natural undulating basic terrain.

[0013] On the basis of the above technical solution, the present invention also provides the following optional technical solution:

[0014] In an optional scheme: In step 1, the method of obtaining the topographic data of the area to be restored of the abandoned marine aquaculture pond is to use a lidar drone aerial survey.

[0015] In one optional scheme, the tidal water level observation data is obtained by accumulating the tidal water level observation data within a hydrological year based on the tidal hydrological observation equipment with known accurate elevation installed in the same area as the beach reclamation and restoration ecological restoration area; the scope of the same area is: the radius is two kilometers; the spatial calculation of water flow inundation by GIS is used, and the maximum tidal water level that can reach the beach reclamation and restoration ecological restoration area is determined by comprehensive analysis to be L max , the minimum tidal level is L min , the average tidal water level is Lˉ.

[0016] In one optional scheme, the specific calculation steps for the inundation elevation that the tide can reach in the beach restoration ecological restoration area are:

[0017] Step (1) Calculation of the underwater elevation of the instrument installation point: The underwater elevation K of the tidal hydrological observation equipment installation point is calculated based on the measured elevation K' of the tidal hydrological observation equipment installation point, minus the installation height h' of the instrument from the water surface and the measured water depth L' at the time when the instrument is installed and put into operation;

[0018] K=K'-h'-L' Formula 1

[0019] Where K is the seabed elevation of the instrument installation point, K' is the elevation of the instrument installation point measured by handheld RTK, h' is the actual installation height of the instrument from the water surface when the instrument is installed, and L' is the water depth measured by the sonar depth sounder when the instrument is installed and put into operation;

[0020] Step (2) assigning tidal water level elevation is based on the water level observation data of the instrument installation point accumulated by the tidal hydrological observation equipment, i.e., the water depth L i , plus the water bottom elevation K of the instrument installation point to calculate the tidal water level elevation h i

[0021] h i =L i +K Formula 2

[0022] In the formula, h i is the elevation value corresponding to the tidal water level at different time periods, L i is the measured tidal water level at different periods, and K is the seabed elevation at the instrument installation point;

[0023] Step (3) The tidal flooding range is determined by the tidal water level h i After screening the water level data within a hydrological year, the maximum tidal water level is determined to be h max 、The minimum tidal water level is h min , the average tidal water level elevation is hˉh. Combined with the measured topographic data of the abandoned marine aquaculture pond restoration area, GIS spatial analysis was performed to determine the maximum, minimum and average inundation range of the tidal zone that can be reached in the beach restoration ecological restoration area.

[0024] In an optional solution: in step 5, the specific method of dividing the transformation area is: based on the actual measured topography of the abandoned marine aquaculture pond to be restored area, combined with the determined terrain transformation elevation interval;

[0025] The low-lying areas with elevation lower than h are filled with soil from the breeding pond dam;

[0026] Keep less than h min The original channel below serves as a tidal channel within the habitat;

[0027] Keep the elevation greater than h max , large platforms with a width of more than 30m are used as resting places for birds during high tide;

[0028] Other areas will be leveled according to the terrain transformation elevation range with a gentle slope of no more than 5° to create a nearly natural undulating basic terrain.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The discrimination method provided by the present invention can realize the accurate judgment of the elevation range of terrain transformation of the ecological restoration project of retiring aquaculture to the beach, effectively guide the implementation of the ecological restoration project of retiring aquaculture to the beach, be beneficial to the restoration of water system and vegetation in the restoration area of ​​retiring aquaculture to the beach, and improve the ecological restoration efficiency of abandoned coastal aquaculture land. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the flow structure of the discrimination method in the present invention.

[0032] Figure 2 It is a schematic diagram of the terrain transformation design of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. The various embodiments listed in the present invention are only used to illustrate the present invention and are not used to limit the scope of the present invention. Any obvious modifications or changes made to the present invention do not depart from the spirit and scope of the present invention.

[0034] In one embodiment, Figure 1 and Figure 2 As shown, a method for determining the elevation interval of terrain transformation in a beach reclamation and beach restoration project includes the following steps:

[0035] 1. Derivation of tidal inundation elevation range

[0036] 1) Topographic data collection: Use laser radar drone aerial survey to obtain the topographic data of the abandoned marine aquaculture pond to be restored, and determine the surface elevation H of the beach ecological restoration area. i , where the maximum elevation is H max , the minimum elevation is H min and the average elevation is ˉH;

[0037] (2) Tidal water level observation: Based on the tidal hydrological observation equipment with known accurate elevation installed in the same area as the restoration area (control radius less than 2 km), the tidal water level observation data within a hydrological year are accumulated, and the spatial calculation of water flow inundation by GIS is used to comprehensively analyze and determine that the maximum tidal water level that can reach the beach restoration ecological restoration area is Lmax , the minimum tidal level is L min , the average tidal water level is Lˉ;

[0038] (3) Calculation of tidal inundation elevation: Based on the known bottom elevation of the tidal hydrological observation equipment installation point and the measured tidal water levels at different time periods, the elevation range h of the beach restoration area that the tide can reach is calculated. i , where the maximum elevation is h max , the minimum elevation is h min , the average elevation is h; the specific tidal flooding elevation that can reach the restoration area is shown in the attached Figure 1 And the following formula;

[0039] Calculation of the bottom elevation of the instrument installation point: The bottom elevation K of the tidal hydrological observation equipment installation point is calculated based on the measured elevation K' of the tidal hydrological observation equipment installation point, minus the installation height h' of the instrument from the water surface and the measured water depth L' at the time the instrument is installed and put into operation.

[0040] K=K'-h'-L' (Formula 1)

[0041] Where K is the seabed elevation of the instrument installation point, K' is the elevation of the instrument installation point measured by handheld RTK, h' is the actual installation height of the instrument from the water surface when the instrument is installed, and L' is the water depth measured by the sonar depth sounder when the instrument is installed and put into operation.

[0042] Tidal water level elevation assignment: based on the tidal water level observation data of the instrument installation point accumulated by the tidal hydrological observation equipment, that is, the water depth L i , plus the water bottom elevation K of the instrument installation point to calculate the tidal water level elevation h i .

[0043] h i =L i +K (Formula 2)

[0044] In the formula, h i is the elevation value corresponding to the tidal water level at different time periods, L i is the measured tidal water level at different periods of time, and K is the seabed elevation at the instrument installation point.

[0045] Tidal flooding range: According to the tidal water level h determined by calculation i , after screening the water level data within a hydrological year cycle, the maximum tidal water level elevation h is determined max 、Minimum tidal water level elevation h min , average tidal water level elevation h, combined with the acquired measured topographic data of the status quo of the abandoned marine aquaculture ponds to be restored, and through GIS spatial analysis, the maximum, minimum and average inundation ranges that the tides can reach in the beach restoration ecological restoration area are determined.

[0046] 2 Analysis of elevation intervals of terrain transformation

[0047] Based on the tidal water level and the measured topographic data of the abandoned aquaculture pond restoration area, the elevation range of the tidal reach of the beach restoration area was determined by joint analysis. min ,h max ], the average elevation is ˉh, and the area below the average elevation ˉh is the frequently flooded area. Considering that the habitat of waterbirds requires certain plant belts and high-platform habitat islands, the elevation interval of the terrain modification for the regional reclamation and beach restoration project is determined to be [hˉ, h max ].

[0048] 3. Renovation area division

[0049] See attached Figure 2 According to the actual measured topography of the abandoned marine aquaculture pond restoration area, the low-lying areas with elevations lower than hˉ will be filled with the soil of the aquaculture pond dam body; the areas with elevations lower than hˉ will be reserved. min The original channel below and above is used as the internal tidal channel of the habitat; the elevation greater than h max , large platforms with a width of more than 30m are used as resting places for birds during high tide; other areas are flattened according to the elevation range of the terrain transformation with a gentle slope of no more than 5° to create a basic terrain with nearly natural ups and downs.

[0050] Implementation case: Liaohe Estuary Wetland Nanxiaohe Retreat Beach Area Terrain Reconstruction Project

[0051] As an important coastal tidal flat, Liaohekou Wetland has large-scale aquaculture ponds, which have been orderly withdrawn in recent years, forming a large area of ​​abandoned aquaculture land. The method for distinguishing the elevation interval of terrain transformation proposed in the present invention is applied in the ecological restoration of Liaohekou Wetland.

[0052] According to the technical principles and technical implementation requirements of the patent of this invention, the terrain transformation project of the Nanxiaohe Retreat and Beach Restoration Area of ​​the Liaohe Estuary Wetland during 2022-2023 was completed with guidance. The main technical applications are as follows:

[0053] (1) Obtaining the elevation of the restoration area. A high-precision LiDAR drone was used to obtain the elevation data DEM of the restoration area, and it was determined that the average elevation of the beach restoration area was 8.8 m, the maximum elevation was 15.4 m, and the minimum elevation was 3.1 m.

[0054] (2) Determination of the tidal inundation range of the restoration area. Based on the hydrological observation equipment (RQ-30a) installed on the west bank of the Liaohe River estuary, combined with the measured elevation of the tidal observation station and the measured terrain elevation of the restoration area, a joint analysis determined that the average tidal water level at the Liaohe River estuary is 2.22m, and the average water level elevation is 7.12m; the highest tidal level at the Liaohe River estuary is 5.1m, and the maximum elevation that can be reached is 10m; the lowest water level at low tide is 0.168m, and the lowest elevation that can be reached is 5.068m. It was comprehensively determined that the elevation range that the Liaohe River estuary tide can reach in the Nanxiaohe Retreat and Beach Restoration Ecological Restoration Area is 5.068m to 10m, with an average elevation of 7.12m.

[0055] (3) Elevation range of terrain transformation in the restoration area. Based on the tidal water level of the Liaohe Estuary Wetland and the elevation range reached during high and low tides, a comprehensive analysis determined that the elevation range of terrain transformation in the Nanxiaohe Retreat and Beach Restoration Ecological Restoration Area is 7.1 to 10 meters. The low-lying areas with elevations below 7.1 meters will be filled with soil from the aquaculture pond dam body; the original channels less than 5.068 meters and below will be retained as tidal channels within the habitat.

[0056] (4) Technology implementation recovery effect

[0057] According to the interpretation of the 2023 image of the restoration area of ​​the Liaohe Estuary South Xiaohe River, the vegetation in the restoration area has increased by 18.052 km 2 , of which Suaeda salsa accounted for 88%, and the water area also increased by 2.304km 2 , environmental conditions have been significantly improved; according to sampling surveys, the average salinity of the saltwort growing zone in the restoration area is 6.18g / kg, and the average salinity in the concentrated growth area is 12.4g / kg, which meets the upper limit of salt for the growth of saltwort in Liaohe Estuary Wetland, 10g / kg-15g / kg. This shows that the soil base conditions after restoration are suitable for the growth of saltwort, and the regional habitat quality has been significantly improved. There are also migratory birds such as plovers and black-headed gulls, which is conducive to the creation of potential water bird habitats.

[0058] The above is only a specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A method for determining the elevation interval of terrain transformation in a beach reclamation and ecological restoration project, characterized in that: The following steps are involved: Step 1: Topographic data collection, obtain the topographic data of the abandoned marine aquaculture pond to be restored, and determine the surface elevation H of the beach ecological restoration area. i , where the maximum elevation is H max , the minimum elevation is H min and the average elevation is Step 2: Tidal water level observation: obtain the measured tidal water level L at different times according to the tidal hydrological observation equipment. i The analysis determined that the maximum tidal water level that can reach the beach restoration area is L max , the minimum tidal level is L min The average tidal level is Step 3: Calculate the tidal inundation elevation. Based on the known bottom elevation of the tidal hydrological observation equipment installation point and the measured tidal water levels at different times, calculate the elevation range h of the beach restoration area that the tide can reach. i , where the maximum elevation is h max , the minimum elevation is h min The average elevation is Step 4: Analyze the elevation range of terrain transformation. According to the tidal water level and the measured terrain data of the proposed restoration area of ​​abandoned marine aquaculture ponds, the tidal elevation range of the beach restoration area is determined as [h min ,h max ], the average elevation is Average elevation The following areas are often flooded areas. Considering that the habitat of waterbirds requires certain plant belts and high-platform habitat islands, the terrain elevation change interval of the regional reclamation and beach restoration project is determined as follows: Step 5: Divide the transformation area. Based on the measured topography of the abandoned marine aquaculture pond restoration area, and using the calculated terrain transformation elevation range as the control range, transform the beach ecological restoration area into a near-natural undulating basic terrain.

2. The method for determining the elevation interval of terrain transformation for the beach reclamation and beach restoration project according to claim 1 is characterized in that: In step 1, the terrain data of the area to be restored for the abandoned marine aquaculture pond is obtained by using a LiDAR drone aerial survey.

3. The method for determining the elevation interval of terrain transformation for the beach reclamation and beach restoration project according to claim 1 is characterized in that: The tidal water level observation data are obtained by accumulating the tidal water level observation data within a hydrological year based on the tidal hydrological observation equipment installed in the same area as the restoration area with known accurate elevation; the scope of the same area is: the radius is two kilometers; the spatial calculation of water flow inundation by GIS is used, and the maximum tidal water level that can reach the ecological restoration area of ​​retreat and beach restoration is determined by comprehensive analysis to be L max , the minimum tidal level is L min The average tidal level is 4. The method for determining the elevation interval of terrain transformation in the beach reclamation and beach restoration project according to claim 1 is characterized in that: The specific calculation steps for the flooded elevation of the restoration area that can be reached by tides are as follows: Step (1) Calculation of the underwater elevation of the instrument installation point: The underwater elevation K of the tidal hydrological observation equipment installation point is calculated based on the measured elevation K' of the tidal hydrological observation equipment installation point, minus the installation height h' of the instrument from the water surface and the measured water depth L' at the time when the instrument is installed and put into operation; K=K'-h'-L' Formula 1 Where K is the seabed elevation of the instrument installation point, K' is the elevation of the instrument installation point measured by handheld RTK, h' is the actual installation height of the instrument from the water surface when the instrument is installed, and L' is the water depth measured by the sonar depth sounder when the instrument is installed and put into operation; Step (2) assigning tidal water level elevation is based on the tidal water level observation data of the instrument installation point accumulated by the tidal hydrological observation equipment, i.e., the water depth L i , plus the water bottom elevation K of the instrument installation point to calculate the tidal water level elevation h i h i =L i +K Formula 2 In the formula, h i is the elevation value corresponding to the tidal water level at different time periods, L i is the measured tidal water level at different periods, and K is the seabed elevation at the instrument installation point; Step (3) The tidal flooding range is determined by the tidal water level h i , after screening the water level data within a hydrological year cycle, the maximum tidal water level elevation h is determined max 、Minimum tidal water level elevation h min , the average tidal water level elevation h, combined with the acquired measured topographic data of the existing status of the proposed restoration area of ​​abandoned marine aquaculture ponds, and through GIS spatial analysis, the maximum, minimum and average inundation range of the tidal restoration area were determined.

5. The method for determining the elevation interval of terrain transformation in the beach reclamation and beach restoration project according to claim 1 is characterized in that: In step 5, the specific method of dividing the transformation area is: based on the actual measured terrain of the abandoned marine aquaculture pond to be restored area, combined with the terrain transformation elevation interval determined by calculation; Lower the elevation The low-lying areas are filled with soil from the breeding pond dam; Keep less than h min The original channel below serves as a tidal channel within the habitat; Keep the elevation greater than h max , large platforms with a width of more than 30m are used as resting places for birds during high tide; Other areas will be leveled according to the terrain transformation elevation range with a gentle slope of no more than 5° to create a nearly natural undulating basic terrain.

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