Marsh wetland degradation restoration method based on contour surface water interception

Abstract

The invention discloses a marsh wetland degradation restoration method based on contour surface water interception, which is suitable for degraded marsh wetlands which are large in water source shortage and rainfall seasonal difference, have no obvious surface water system and depend on underground water and overland flow to maintain the wetland habitat. Comprising the following steps that a restoration area is defined, the gradient direction and the water flow direction are measured, restoration units are divided, local materials are used, soil is 3, stones are 1, a ridge is rammed, the width of the ridge is 35-100 cm, the height of the ridge is 25-35 cm, the construction time is selected, and vegetation is restored and patrolled and maintained; the waterlogging area is formed by ramming the ridge along the contour line to intercept overland overflow and rainfall, and the wetland habitat and vegetation communities are restored and maintained by utilizing the self-restoration capability of the ecological system; the method is easy to operate, small in manual intervention, eco-friendly, remarkable and stable in restoration effect and suitable for ecological restoration of the degraded marsh wetland.

Description

Technical Field

[0001] The present invention relates to the technical field of wetland ecological restoration, and in particular to a method for restoring degraded swamp wetlands based on contour line surface water interception. The method is suitable for the restoration of degraded swamp wetlands that have no obvious surface water system before degradation due to water shortage and large seasonal differences in precipitation, rely on groundwater and surface flow as the main water supply, and are affected by seasonal precipitation changes, resulting in habitat degradation or decreased vegetation community dominance. This is an ecological restoration technology that achieves hydrological stabilization and vegetation community recovery through contour line micro-topography transformation and local material use. Background Art

[0002] As important ecosystems, marsh wetlands play a key role in hydrological regulation, biodiversity conservation, and carbon sequestration. However, due to climate change, declining groundwater levels, overgrazing, and human activities (such as agricultural reclamation and infrastructure development), many marsh wetlands are experiencing degradation, manifested by reduced surface water, loss of wetland habitat, and a decline or even disappearance of dominant vegetation communities. This is particularly true in marsh wetlands without significant surface water systems (rivers and streams), where hydrology primarily depends on groundwater recharge and overland flow. These hydrology is significantly affected by seasonal precipitation variations, making restoration difficult and leaving clear evidence of human intervention.

[0003] Existing wetland restoration technologies primarily target different types of wetland environments, with diverse approaches, but they still have numerous shortcomings. First, restoration technologies for coastal or lake wetlands are relatively mature, such as those that regulate hydrological conditions through the construction of ditches, the installation of dams, or artificial water replenishment. Patent CN118619496A discloses a method for ecological restoration of degraded wetlands, which regulates hydrology through the construction of ditches and restoration of vegetation. However, this method is primarily applicable to wetlands with well-developed surface water systems and does not consider the characteristics of swamp wetlands without surface water systems.

[0004] Secondly, some technologies attempt to restore wetland habitats through soil improvement and vegetation reintroduction. For example, patent CN109853461A proposes an ecological restoration method for plateau swamp wetland erosion gullies. By building different buffer dams in different gully sections, such as tower head buffer dams, gravel buffer dams, and peat buffer dams, the water flow rate is slowed down, the vegetation coverage rate is increased, and water erosion is avoided. However, this method is more suitable for plateau swamp wetland erosion gullies with obvious surface water systems, and is not specifically targeted at swamp wetlands without obvious surface water systems. In addition, the patent does not describe in detail the specific parameters of the buffer dam (such as size and material ratio), resulting in insufficient construction operability. At the same time, this method does not consider the impact of construction time on hydrology and vegetation, and may cause secondary disturbance to the wetland during construction during the dry season or heavy rainfall period.

[0005] Third, the concept of "near-natural" restoration has gained increasing attention in recent years, emphasizing the utilization of the natural successional capacity of ecosystems for restoration. Patent CN110915344A discloses a near-natural wetland restoration technology that uses local materials to construct microtopography to promote vegetation and hydrological recovery. While this method reduces the interference of foreign materials, its implementation lacks specificity. For example, it lacks clarity on how to adapt to the hydrological characteristics of marsh wetlands that lack surface water systems and rely on groundwater recharge. Furthermore, the technology lacks specific construction parameters (such as microtopography structure dimensions and construction timing), making it difficult to ensure the stability of the restoration results.

[0006] Fourth, in recent years, the concept of “near-natural” restoration has attracted attention in the field of wetland ecological restoration. Patent CN113802511A discloses a method for constructing an ecological buffer zone, which intercepts runoff through structures such as wave-shaped energy-dissipating grass-planted ditches and surface runoff interception ditches, and promotes ecological recovery by using vegetation and microbial restoration blocks. This method utilizes the ability of natural succession and reduces interference from external materials. However, it does not clearly adapt to the hydrological characteristics of swamp wetlands without surface water systems and relying on groundwater recharge, nor does it provide specific parameters such as micro-topography structure size and construction time selection. As a result, its application in special wetland types is limited, and the stability of the restoration effect is difficult to guarantee.

[0007] In addition, research on special wetland types such as alpine wetlands is gradually increasing. Alpine wetlands (such as the Jingning Wangdongyan alpine wetland in southeastern China) are usually located in areas with high altitudes, complex hydrological conditions, scarce surface water systems, and mainly rely on groundwater and surface runoff for recharge. They are greatly affected by seasonal precipitation. The restoration of alpine wetlands often adopts a combination of vegetation replanting and small-scale hydrological engineering, but existing technologies often ignore the importance of terrain fine-tuning, and construction materials are mostly foreign soil or artificial components, which can easily destroy the original landscape and ecological balance of alpine wetlands. In addition, the climatic conditions of alpine wetlands (such as low temperature and high rainfall) place higher requirements on construction time and vegetation restoration, while existing technologies lack targeted construction time selection and long-term maintenance strategies.

[0008] In summary, existing wetland restoration technologies have the following deficiencies: (1) There is a lack of specialized restoration methods for marsh wetlands without obvious surface water systems, especially alpine wetlands; (2) The parameters and construction processes for micro-topography transformation are not clear enough and are not practical enough; (3) They often rely on external materials or artificial water sources, which can easily damage the original wetland habitat and landscape; (4) The selection of construction time lacks scientific basis, which may cause secondary disturbance to the wetland; (5) There is a lack of long-term inspection and maintenance mechanisms, and the restoration effect is difficult to sustain. Therefore, there is an urgent need for a restoration method for degraded marsh wetlands without obvious surface water systems that utilizes local materials and the self-repair ability of the ecosystem to achieve long-term hydrological stability and vegetation community recovery. Summary of the Invention

[0009] The purpose of the present invention is to solve the defects of the existing technology in the restoration of degraded swamp wetlands without obvious surface water systems, such as poor restoration effect, foreign construction materials and insufficient habitat stability. A method for restoring degraded swamp wetlands based on contour surface water interception is proposed. By measuring the slope and aspect, using local materials to build earth ridges and choosing a reasonable construction time, a water accumulation area is constructed, and the self-sustaining and self-repairing ability of the swamp wetland ecosystem is utilized to form a long-term stable wetland habitat and vegetation community.

[0010] In order to achieve the above object, the present invention adopts the following technical solutions: A method for restoring degraded marsh wetlands based on contour line surface water interception comprises the following steps: S1: Define the restoration area: Determine the scope of the degraded marsh wetland through field surveys or aerial photography and remote sensing analysis, confirm its hydrological characteristics without obvious surface water systems and the degree of vegetation degradation; S2: Determine the slope, aspect, and water flow direction: Use surveying instruments to measure the slope, aspect, water flow direction, and topographic change trends of the restoration area, and draw contour maps; S3: Divide the restoration unit: According to the contour map, divide the restoration area into multiple restoration units along the contour lines, and control the slope change of each unit within 5%; S4: Local materials: Soil and stones are collected from the restoration area or adjacent areas, and mixed in a volume ratio of 3:1 as rammed earth materials; S5: Rammed earth ridges: Rammed earth ridges are built along the contour lines in each restoration unit. The width of the ridges is 35-100 cm and the height is 25-35 cm, forming a waterlogged area enclosed by 1-3 sides. S6: Construction time selection: Avoid the rainy season, flood season and vegetation growth season. It is recommended to avoid heavy rainfall in March and April each year. S7: Vegetation Restoration: Transplant or propagate some wetland vegetation near the surface of the rammed earth bank, relying on the hydrological improvement of the waterlogged area and utilizing the self-repairing ability of the marsh wetland ecosystem to promote the natural regeneration of wetland vegetation; S8: Inspection and maintenance: After construction, regularly inspect the embankment structure and the hydrological conditions of the waterlogged area, especially the integrity of the embankment after rainfall and heavy rainfall, and the duration of surface water retention. Adjustments and maintenance should be made in a timely manner according to local conditions until the hydrological environment and vegetation community are stabilized.

[0011] As a further technical solution of the present invention, in S1, the restoration area is defined according to the typical characteristics of the degraded swamp wetland, such as lack of water source and moisture and change of vegetation community.

[0012] As a further technical solution of the present invention, in said S1, the typical characteristics of the degraded swamp wetland include: no obvious overland flow, low soil moisture content; formation of seasonal gullies, discharge of surface water; reduction or even disappearance of swamp vegetation, and invasion of terrestrial vegetation.

[0013] As a further technical solution of the present invention, in S2, the slope range is 0.1%-5%, and the contour line accuracy requirement is within 500mm.

[0014] As a further technical solution of the present invention, in S5, the ridge is compacted by a mixed process, with a volume ratio of soil: stone = 3:1 to ensure structural stability; the width of the ridge is preferably 50 cm, and the height is preferably 25 cm.

[0015] As a further technical solution of the present invention, in S6, the construction time is preferably spring every year.

[0016] As a further technical solution of the present invention, in S7, the vegetation restoration includes artificially introducing local vegetation seeds or seedlings on the top of the ridge, with a planting density of 10-20 plants / m².

[0017] As a further technical solution of the present invention, in said S8, the inspection and maintenance cycle is once every 3-6 months, and inspections are increased after precipitation and heavy precipitation. The inspection content includes the damage of the earth embankment and the duration of intercepting surface water. The maintenance content includes repairing damaged earth embankments and removing silt.

[0018] The beneficial effects of the present invention are: 1. Highly targeted: For degraded swamp wetlands without obvious surface water systems and relying on groundwater and surface overland flow, the overland flow can be effectively intercepted through the transformation of contour micro-topography, thereby improving hydrological conditions and adapting to seasonal precipitation changes.

[0019] 2. Eco-friendly: Using local materials (3 soil: 1 stone) to avoid interference of foreign materials on wetland habitats and landscapes, in line with the concept of near-natural restoration.

[0020] 3. Precise construction: Through slope and aspect measurement and contour line division, the position and size of the earthen embankment are precisely designed (width 35-100cm, height 25-35cm) to ensure the hydrological regulation effect in the waterlogged area.

[0021] 4. Long-term stability: By utilizing the self-sustaining and self-repairing capabilities of the ecosystem, combined with regular inspections and maintenance, we can achieve long-term stability of hydrology and vegetation, and ensure sustainable restoration effects.

[0022] 5. Easy to operate: The method and steps are clear, the construction process is simple, and it is suitable for degraded swamp wetlands of different sizes, with strong promotion and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic plan view of the contour division of the restoration area and the rammed earth ridge in Example 1. In the figure, 1, restoration area; 2, contour lines; 3, original water system; 4, native vegetation; 5, earth ridge; 6, waterlogged area (designed intercepted water surface); Figure 2 This is a schematic diagram of the cross-sectional structure of the earth ridge and vegetation restoration in Example 1. In the figure, 4 is native vegetation; 5 is earth ridge; 6 is waterlogging area (designed interception water level); 7 is planted vegetation; Figure 3 This is a flow chart of a method for restoring swamp wetland degradation based on contour surface water interception proposed by the present invention. DETAILED DESCRIPTION

[0024] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0025] Please see the attached Figure 3 A method for remediating marsh wetland degradation based on contour surface water interception comprises the following steps: S1: Define the restoration area: Determine the scope of the degraded marsh wetland through field surveys or aerial photography and remote sensing analysis, confirm its hydrological characteristics without obvious surface water systems and the degree of vegetation degradation; The restoration area is defined based on the typical characteristics of degraded marsh wetlands, including lack of water and moisture and changes in vegetation communities; typical characteristics of degraded marsh wetlands include: no obvious surface flow, low soil moisture content; formation of seasonal gullies and discharge of surface water; reduction or even disappearance of marsh vegetation, and invasion of terrestrial vegetation.

[0026] S2: Determine the slope, aspect, and water flow direction: Use surveying instruments to measure the slope, aspect, water flow direction, and topographic change trends of the restoration area, and draw contour maps; The slope range is 0.1%-5%, and the contour line accuracy requirement is within 500mm.

[0027] S3: Divide the restoration unit: According to the contour map, divide the restoration area into multiple restoration units along the contour lines, and control the slope change of each unit within 5%; S4: Local materials: Soil and stones are collected from the restoration area or adjacent areas, and mixed in a volume ratio of 3:1 as rammed earth materials; S5: Rammed earth ridges: Rammed earth ridges are built along the contour lines in each restoration unit. The width of the ridges is 35-100 cm and the height is 25-35 cm, forming a waterlogged area enclosed by 1-3 sides. The earth embankment adopts a mixed compaction process, with a volume ratio of soil: stone = 3:1 to ensure structural stability; the width of the earth embankment is preferably 50cm and the height is preferably 25cm.

[0028] S6: Construction time selection: Avoid the rainy season, flood season and vegetation growth season. It is recommended to avoid heavy rainfall in March and April each year. The preferred construction time is spring every year.

[0029] S7: Vegetation Restoration: Transplant or propagate some wetland vegetation near the surface of the rammed earth bank, relying on the hydrological improvement of the waterlogged area and utilizing the self-repairing ability of the marsh wetland ecosystem to promote the natural regeneration of wetland vegetation; Vegetation restoration involves artificially introducing native plant seeds or seedlings on top of the ridge, with a planting density of 10-20 plants / m².

[0030] S8: Inspection and maintenance: After construction, regularly inspect the embankment structure and the hydrological conditions of the waterlogged area, especially the integrity of the embankment after rainfall and heavy rainfall, and the duration of surface water retention. Adjustments and maintenance should be made in a timely manner according to local conditions until the hydrological environment and vegetation community are stabilized.

[0031] The inspection and maintenance cycle is once every 3-6 months, with additional inspections after rainfall and heavy rainfall. The inspection content includes the damage to the earthen embankment and the duration of surface water interception. The maintenance content includes repairing damaged earthen embankments and removing silt.

[0032] Example 1 The degraded marsh wetlands of the Jingning Wangdongyan Alpine Wetland Nature Reserve (located in Jingning She Autonomous County, Lishui City, Zhejiang Province, China) are located in a high mountain area at an altitude of approximately 1,300 meters. Prior to degradation, the wetland had no significant surface drainage system, and its hydrology relied on groundwater and overland flow. This was significantly influenced by seasonal precipitation, with annual precipitation of approximately 1,800 mm, primarily concentrated between May and August. The wetland vegetation community is dominated by Alnus chinensis, Miscanthus sinensis, Marsh Grass, Juncus citriodora, and Scirpus chinensis. Agricultural reclamation and canal construction in the 1990s damaged the wetland ecosystem, leading to drought, falling water levels, and decreased vegetation cover.

[0033] The repair method of the present invention is adopted, and the specific steps are as follows: S1: Define the restoration area: Determine the degraded area through drone aerial photography and field surveys ( Figure 1 1) is 10 hectares, with no obvious surface water systems such as rivers and streams, and the hydrological characteristics are groundwater recharge and surface flow, and the vegetation is severely degraded; S2: Determine the slope and direction: Use RTK surveying equipment to measure the terrain, with a slope range of 0.1%-5% (such as Figure 1 As shown), the slope direction is southeast, draw the contour map ( Figure 1 2 in the figure, height spacing 500mm); S3: Divide the repair area: According to the contour map ( Figure 1 ), the restoration area was divided into 8 blocks, each with an area of ​​approximately 1.25 hectares, and the slope change was controlled within 0.3%; S4: Local materials: Collect surface soil and stones (stone particle size 5-20cm) in the restoration area, mix them in a volume ratio of 3:1, and the total amount of mixed materials is about 500m³; S5: Rammed earth ridge: Rammed earth ridge along the contour line ( Figure 1 5), ridge width 500mm, height 250mm (reference Figure 2 ), using mixed compaction technology, with a volume ratio of 3 soil: 1 stone, each block forms a 2-sided enclosed water area ( Figure 1 6), the total length of the rammed earth embankment is about 2000m, the groundwater level ( Figure 1 3) 100 mm below the ridge; S6: Construction time selection: Choose autumn (mid-October) to avoid the flood season and heavy rainfall from May to August. The construction period is 15 days. S7: Vegetation restoration: relying on waterlogged areas ( Figure 1 6) of the water supply, and the natural germination of Carex tricholoma and Carex sphaerocarpa was observed ( Figure 1 4 in ); to accelerate recovery, plant vegetation on top of the ridge ( Figure 2 7) artificial sowing of marsh grass seeds (15 plants / m²), with a coverage rate of 90%; S8: Inspection and maintenance: Inspections are carried out every three months. If some earthen embankments are found to be slightly damaged due to rainfall erosion, they are promptly repaired. 18 months after the repairs, the water depth in the accumulated water area stabilizes at 5-10cm, and the wetland vegetation coverage rate recovers to 75%, forming a stable habitat.

[0034] From the above description, it can be seen that the above-mentioned embodiments of the present invention achieve the following technical effects: strong targeting: for degraded swamp wetlands without obvious surface water systems and relying on groundwater and surface flow, the contour micro-topography transformation is used to effectively intercept the flow, improve the hydrological conditions, and adapt to seasonal precipitation changes.

[0035] Eco-friendly: Using local materials (3 soil: 1 stone) to avoid interference of foreign materials on wetland habitats and landscapes, in line with the concept of near-natural restoration.

[0036] Precise construction: Through slope and aspect measurement and contour line division, the position and size of the earthen embankment are precisely designed (width 35-100cm, height 25-35cm) to ensure the hydrological regulation effect in the waterlogged area.

[0037] Long-term stability: Utilizing the self-maintenance and self-repair capabilities of the ecosystem, combined with regular inspections and maintenance, we can achieve long-term stability of hydrology and vegetation, and ensure sustainable restoration effects.

[0038] Easy to operate: The method and steps are clear, the construction process is simple, and it is suitable for degraded swamp wetlands of different sizes, with strong promotion and application value.

[0039] It should be understood by those skilled in the art that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples. Within the scope of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0040] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for restoring swamp wetland degradation based on contour line surface water interception, characterized in that: The following steps are involved: S1: Define the restoration area: Determine the scope of the degraded marsh wetland through field surveys or aerial photography and remote sensing analysis, confirm its hydrological characteristics without obvious surface water systems and the degree of vegetation degradation; S2: Determine the slope, aspect, and water flow direction: Use surveying instruments to measure the slope, aspect, water flow direction, and topographic change trends of the restoration area, and draw contour maps; S3: Divide the restoration unit: According to the contour map, divide the restoration area into multiple restoration units along the contour lines, and control the slope change of each unit within 5%; S4: Local materials: Soil and stones are collected from the restoration area or adjacent areas, and mixed in a volume ratio of 3:1 as rammed earth materials; S5: Rammed earth ridges: Rammed earth ridges are built along the contour lines in each restoration unit. The width of the ridges is 35-100 cm and the height is 25-35 cm, forming a waterlogged area enclosed by 1-3 sides. S6: Construction time selection: Avoid the rainy season, flood season and vegetation growth season during construction; S7: Vegetation restoration: Transplant or propagate some wetland vegetation near the surface of the rammed earth embankment; S8: Inspection and maintenance: After construction, regularly inspect the embankment structure and the hydrological conditions of the waterlogged area, and make appropriate adjustments and maintenance according to local conditions until the hydrological environment and vegetation community are stabilized.

2. The method for restoring swamp wetland degradation based on contour surface water interception according to claim 1, characterized in that: In said S1, the restoration area is defined according to the typical characteristics of degraded marsh wetlands, such as lack of water source and moisture and change of vegetation community.

3. The method for restoring swamp wetland degradation based on contour surface water interception according to claim 2, characterized in that: In S1, the typical characteristics of degraded marsh wetlands include: no obvious overland flow and low soil moisture content; formation of seasonal gullies and discharge of surface water; reduction or even disappearance of marsh vegetation and invasion of terrestrial vegetation.

4. The method for restoring swamp wetland degradation based on contour surface water interception according to claim 1, characterized in that: In S2, the slope range is 0.1%-5%, and the contour line accuracy requirement is within 500mm.

5. The method for restoring swamp wetland degradation based on contour surface water interception according to claim 1, characterized in that: In S5, the earth ridge is compacted by a mixed compaction process, with a volume ratio of soil: stone = 3:1 to ensure structural stability; the width of the earth ridge is preferably 50 cm, and the height is preferably 25 cm.

6. The method for restoring swamp wetland degradation based on contour surface water interception according to claim 1, characterized in that: In the above S6, the construction time is preferably every spring.

7. The method for restoring degraded marsh wetlands based on contour surface water interception according to claim 1, characterized in that: In S7, the vegetation restoration includes artificially introducing native vegetation seeds or seedlings on the top of the ridge at a planting density of 10-20 plants / m².

8. The method for restoring degraded marsh wetlands based on contour surface water interception according to claim 1, characterized in that: In said S8, the inspection and maintenance cycle is once every 3-6 months, and inspections are increased after rainfall or heavy rainfall. The inspection content includes the damage of the earthen ridge and the duration of intercepting surface water. The maintenance content includes repairing the damaged earthen ridge and removing silt.

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