An erosion ditch composite ecological restoration method suitable for a freeze-thaw erosion environment of a hilly and flat region

Abstract

The present application provides an erosion ditch composite ecological restoration method suitable for the freeze-thaw erosion environment of hilly and rolling areas, which combines engineering measures and biological measures, and integrates local farming patterns to realize the coordinated development of rapid ditch consolidation, ecological restoration and agricultural production, and can effectively solve the problems of single, poor adaptability and low sustainability of the prior art.

Description

Technical Field

[0001] This invention relates to the field of soil and water conservation and ecological restoration technology for freeze-thaw erosion environments in hilly and undulating areas, specifically to a composite ecological restoration method for erosion gullies. Background Technology

[0002] The soil and water conditions in the hilly and rolling hill areas are affected by multiple factors, such as concentrated summer rainfall, intense freeze-thaw cycles, and disturbance from sloping farmland cultivation. As a result, erosion gullies are densely developed and expand rapidly. Problems such as headwater erosion, bank collapse, and gully bed incision occur frequently. Large areas of contiguous farmland are damaged and fragmented, soil fertility continues to degrade, and the risk of flooding and siltation in the surrounding areas is exacerbated, which seriously restricts regional agricultural production and sustainable land use.

[0003] Current technologies for controlling gully erosion under freeze-thaw erosion conditions in hilly and rolling hilly areas have significant shortcomings. Most methods rely on single engineering or biological measures. Traditional engineering measures, such as masonry stone embankments, concrete revetments, and gabion slope protection, can stabilize gullies in the short term, but they are expensive, complex to construct, and have poor ecological compatibility. They are not suitable for the freeze-thaw cycle characteristics of the land under these conditions and are prone to problems such as frost heave cracking, local collapse, and failure, and they also damage the original ecological structure of the gully. Simple biological measures rely solely on the planting of native forests and grasses, which are slow to stabilize the soil and control erosion. For actively developing gullies, they cannot quickly curb the advance of the gully head and the expansion of the gully banks. In addition, the gully sites are barren and have poor water retention capacity, resulting in low vegetation survival rates, making it difficult to maintain the control effect in the long term.

[0004] Meanwhile, existing restoration technologies generally lack local adaptability. Most solutions fail to consider regional sloping farmland cultivation patterns, resulting in a disconnect between restoration projects and agricultural production. This leads to low farmer participation and inadequate post-remediation management, making it difficult to consolidate the restoration results. Furthermore, some technologies rely on externally purchased specialized restoration materials, further increasing costs and failing to meet the demand for low-cost, large-scale restoration of large, scattered erosion gullies in the region. Therefore, developing a composite restoration method that does not involve new materials, relies solely on local resources, is adapted to regional characteristics, and balances erosion control effectiveness with ecological benefits has become an urgent technical problem to be solved in the field of frozen-thaw erosion gully management in hilly and rolling hill areas. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies and solve the technical problems of single-technology erosion gully management, poor erosion control effect, weak freeze-thaw adaptability, high cost, and disconnect between management and agricultural production, the purpose of this invention is to provide a composite ecological restoration method for erosion gullies adapted to the freeze-thaw erosion environment of hilly and rolling hill areas. It abandons the research and use of new materials and constructs a full-section layered restoration system of "engineering solidification + biological revegetation + agricultural synergy". It does not rely on purchased special materials, but uses local materials to achieve rapid erosion control and long-term ecological restoration. It is suitable for the management of various small and medium-sized active erosion gullies in hilly and rolling hill areas, and is easy for grassroots teams and farmers to implement.

[0006] This invention is achieved through the following technical solution: a composite ecological restoration method for erosion gullies adapted to the freeze-thaw erosion environment of hilly and rolling hill areas, the method comprising: Step 1: Preliminary survey and site preparation. Conduct on-site surveys of the length, depth, slope and degree of erosion of the gully. Clear loose gravel, weeds and debris from the gully and slope. Manually level steep slopes. Compact the gully bottom and slope toe foundations. Plan the runoff diversion route and determine the locations of each protective structure. Step 2: Construction of protection for the bank top and ditch head. Prioritize the completion of the intercepting ditch and buffer zone on the bank top, build the arc-shaped intercepting embankment at the ditch head, and compact and reinforce it to ensure no leakage or collapse; Step 3: Construction of the ditch bottom and slope toe. Along the longitudinal direction of the ditch bottom, build gabion energy dissipation embankments at the set intervals, and simultaneously build gabion toe protection at the slope toe to ensure that the gabion structure is tightly connected, buried to the standard depth, and is not easily deformed in freeze-thaw climate. Step 4: Slope protection and vegetation planting. After the slope is trimmed, ecological bags or old tires are laid to protect the slope. Then, live willow stumps, sea buckthorn, and native shrubs such as Caragana korshinskii are planted at the head of the ditch, the foot of the slope, and the entire slope. Herb seeds are evenly sown and thoroughly watered to ensure that the vegetation is in close contact with the local soil. Step 5: Post-repair management. After the restoration is completed, implement a short-term grazing ban for 3-6 months to prevent livestock and poultry from trampling and damaging the gabion structure. Regularly inspect the integrity of the gabion structure and the survival of the vegetation every month, and promptly replant dead seedlings and repair damaged engineering structures. After the vegetation has grown into a forest, no meticulous management is required, and long-term erosion control can be achieved by relying on natural succession. Example

[0007] Preliminary surveys and site preparation involved on-site mapping combined with drone aerial photography to determine the length, depth, slope, and erosion level distribution of the entire erosion gully. Key treatment areas, such as the headwaters erosion zone and the toe scouring zone, were marked. Subsequently, 150 m³ of silt, loose gravel, weeds, and debris were cleared from the gully. The 38° natural steep slope was manually leveled to a uniform 28°. A frog-type rammer was used in conjunction with manual layering to compact the gully bottom and toe foundation, with a compaction degree controlled above 85%. Based on the cultivation direction and runoff direction of the surrounding sloping farmland, four runoff diversion routes were planned, and the specific locations and construction dimensions of protective structures such as the intercepting gully on the bank, the arc-shaped intercepting embankment at the gully head, the gabion energy dissipation embankment, and the gabion toe protection were precisely determined.

[0008] For the protection construction of the riverbank top and gully head, priority is given to the riverbank top protection project. At the boundary between the riverbank top and the cultivated land, an earthen interception ditch is excavated. The interception ditch is 0.9m wide and 0.7m deep. A 2.0m wide herbaceous buffer zone is prepared on the outside of the interception ditch to prevent agricultural runoff from directly flowing into the erosion gully. In the core area of ​​source erosion at the gully head, an arc-shaped interception embankment is constructed using a layered compaction process with local clay mixed with crushed stone. The interception embankment is 0.6m wide at the top, 1.3m wide at the bottom, and 0.8m high. A layer of crushed stone is laid for every 30cm of compacted soil to enhance structural stability. After the construction is completed, the surface of the interception embankment is treated with anti-seepage to ensure that the overall structure does not leak or collapse, thus curbing source erosion at the gully head from the source.

[0009] For the construction of the gully bottom and slope toe, gabion energy dissipation embankments filled with natural pebbles are laid longitudinally along the bottom of the erosion gully at intervals of 18m, perpendicular to the direction of water flow. The gabions are made of locally sourced galvanized iron wire mesh and filled with natural pebbles with a particle size of 15-35cm. The overall height of the energy dissipation embankment is 18cm and the burial depth is 35cm, with the burial depth portion being compacted and fixed with clay. Simultaneously, gabion toe protection is constructed on both sides of the slope toe of the erosion gully. The gabion toe protection is constructed strictly according to the dimensions of 50cm wide, 40cm high, and 50cm burial depth. The structural units of the gabion energy dissipation embankment and the gabion toe protection are tightly connected, and the gaps are filled with fine pebbles to ensure the overall structure is solid and adaptable to the regional freeze-thaw cycle climate characteristics, avoiding frost heave deformation problems.

[0010] After the slope was trimmed to meet standards, ecological bags were selected as the slope protection material due to the overall slope angle of 28°. The ecological bags were filled with a mixture of local topsoil and well-rotted farmyard manure. The bags were laid in layers from bottom to top along the slope, with adjacent bags secured using fasteners to ensure the slope protection structure remained stable and did not slip or detach. Following the slope protection construction, vegetation was planted throughout the area. At the toe of the slope, multiple rows of live willow stumps were laid in a staggered pattern. The stumps were healthy branches with a diameter of 3-6cm, buried at a depth of 80cm, with a spacing of 0.25m, for a total of 9 stumps. Arrange the slope to form a soil-stabilizing zone; plant sea buckthorn and caragana native shrubs at the head of the ditch, to the foot of the slope, and on the entire slope surface, with a plant spacing of 1.0m × 1.2m; then evenly sow seeds of perennial herbs such as alfalfa, sand fern, and Kentucky bluegrass at a sowing rate of 20g / m²; after the vegetation is planted, thoroughly irrigate to ensure that the vegetation roots are in close contact with the local soil, thereby improving the soil-stabilizing ability of the roots and the survival rate of the vegetation.

[0011] In the later stages of management and maintenance, after the overall restoration project is completed, protective fences will be set up around the erosion gully, and a short-term grazing ban will be implemented for four months to prohibit livestock and poultry from entering and trampling on the vegetation seedlings. During the grazing ban, local residents will be arranged to conduct a comprehensive inspection once a month, focusing on checking the structural integrity of the gabion energy dissipation embankment and gabion footing, as well as the ecological bag slope protection and vegetation growth. Ecological bags that are partially damaged by rainstorms will be repaired in a timely manner, and dead sea buckthorn, caragana seedlings and willow stumps will be replanted in a timely manner. After the vegetation has grown into a forest, intensive artificial management will be discontinued, and the self-repair and long-term erosion control of the erosion gully ecosystem will be achieved by relying on the natural succession of the region. At the same time, the normal cultivation function of the surrounding sloping farmland will be preserved to achieve the coordinated development of ecological governance and agricultural production.

Claims

1. A composite ecological restoration method for erosion gullies adapted to the freeze-thaw erosion environment of hilly and rolling hill areas, characterized in that, The method includes: It does not involve new materials and adopts a full-section layered treatment model of "gully head control + gully bottom erosion control + slope toe protection + slope greening + bank top interception". It integrates localized engineering measures and native biological measures to achieve rapid erosion control and long-term ecological restoration of erosion gullies, which is suitable for the freeze-thaw erosion environment of hilly and rolling hill areas. Step 1: Preliminary survey and site preparation. Conduct on-site surveys of the length, depth, slope and degree of erosion of the gully. Clear loose gravel, weeds and debris from the gully and slope. Manually level steep slopes. Compact the gully bottom and slope toe foundations. Plan the runoff diversion route and determine the locations of each protective structure. Step 2: Construction of protection for the bank top and ditch head. Prioritize the completion of the intercepting ditch and buffer zone on the bank top, build the arc-shaped intercepting embankment at the ditch head, and compact and reinforce it to ensure no leakage or collapse; Step 3: Construction of the ditch bottom and slope toe. Along the longitudinal direction of the ditch bottom, build gabion energy dissipation embankments at the set intervals, and simultaneously build gabion toe protection at the slope toe to ensure that the gabion structure is tightly connected, buried to the standard depth, and is not easily deformed in freeze-thaw climate. Step 4: Slope protection and vegetation planting. After the slope is trimmed, ecological bags or old tires are laid to protect the slope. Then, live willow stumps, sea buckthorn, and native shrubs such as Caragana korshinskii are planted at the head of the ditch, the foot of the slope, and the entire slope. Herb seeds are evenly sown and thoroughly watered to ensure that the vegetation is in close contact with the local soil. Step 5: Post-repair management. After the restoration is completed, implement a short-term grazing ban for 3-6 months to prevent livestock and poultry from trampling and damaging the gabion structure. Regularly inspect the integrity of the gabion structure and the survival of the vegetation every month, and promptly replant dead seedlings and repair damaged engineering structures. After the vegetation has grown into a forest, no meticulous management is required, and long-term erosion control can be achieved by relying on natural succession.

2. The repair method according to claim 1, characterized in that, The specific layout of the zoned protection is as follows: an arc-shaped intercepting embankment made of compacted local clay and gravel is set up on the outer side of the gully head, combined with deep-rooted native shrubs to consolidate the soil and curb headward erosion; every 15-20 m along the bottom of the gully, gabion energy dissipation embankments filled with natural pebbles are set up vertically to the water flow to slow down the water flow, intercept sediment, and prevent the gully bed from eroding; gabion toe protection combined with living native shrubs and willow stakes is used at the toe of the slope to form a rigid-flexible composite protection zone to prevent the toe of the slope from being eroded and collapsed; the slope surface is leveled to 25°-30°, with ecological bags used on gentle slopes and waste tires used as slope protection on steep slopes, and native shrubs and perennial herbs are planted throughout the area; soil intercepting ditches and herbaceous buffer zones are set up at the junction of the bank top and cultivated land to block the erosion of agricultural runoff.

3. The repair method according to claim 2, characterized in that, Live shrub stumps are arranged in multiple rows along the foot of the slope, with a spacing of 0.2-0.3 m between plants, a stump diameter of 2-7 cm, and a burial depth of 60-100 cm. Native shrubs include sea buckthorn and caragana, and herbaceous plants include alfalfa, sand fern, and Kentucky bluegrass. The survival rate of the vegetation is not less than 85%.

4. The repair method according to claim 1, characterized in that, The construction sequence is as follows: first, construct the interception ditch on the top of the bank and the interception embankment at the head of the ditch; then, build the gabion energy dissipation embankment at the bottom of the ditch and the gabion toe protection at the foot of the slope; then, repair the slope and build ecological bags or waste tire slope protection; finally, plant vegetation and water it to help it settle down; after restoration, implement a short-term grazing ban for 3-6 months, and conduct regular inspections and replanting, without the need for meticulous long-term management.

5. The repair method according to claim 2, characterized in that, The gabion energy dissipation embankment is 15-20 cm high and buried 30-40 cm deep. The gabion foot protection is 50 cm wide, 40 cm high, and buried 50 cm deep. All of them are made of local natural stone, which is suitable for the freeze-thaw cycle climate of the black soil area and is not easy to freeze and deform. All materials are sourced locally and no special repair materials are purchased from outside. The treatment cost is lower than that of traditional engineering measures.

6. The repair method according to claim 1, characterized in that, This method is applicable to the treatment of small, active gullies in the freeze-thaw erosion environment of hilly and rolling hill areas. After restoration, the vegetation coverage rate is no less than 85%, which can effectively curb the advance of the gully head, the expansion of the gully bank and the gully bed erosion. It also takes into account the treatment of gullies and the normal cultivation of surrounding sloping farmland, so as to achieve the synergy between ecological benefits and agricultural production.