Trench erosion prevention system and method for eroded land of bamboo forest by comprehensive utilization of bamboo resources

Abstract

The present application provides a bamboo forest erosion poor land gully erosion prevention system and method for comprehensive utilization of bamboo resources, which comprises an upper catchment area runoff dispersion system arranged above the gully catchment area, a gully head source erosion prevention system arranged in the gully source erosion section, a gully channel energy dissipation and flow reduction system arranged in the gully main channel, an ecological grass gully arranged downstream of the gully water outlet, and a bamboo valley system distributed at different elevations of the gully. The present application closely surrounds the bamboo forest erosion poor land gully erosion prevention, and the prevention technology has low cost. The materials used in the present application do not involve concrete, steel bars and traditional water and soil conservation spraying mixed chemical materials, and the prevention technology has high ecological property. The present application innovates the whole-chain gully prevention system of "catchment area flow separation-gully head stabilization-gully channel protection-gully tail adsorption", and the prevention technology has obvious effect.

Description

Technical Field

[0001] This invention relates to the field of soil and water conservation technology, specifically to a system and method for preventing and controlling gully erosion in bamboo forest erosion-prone areas by comprehensively utilizing bamboo resources. Technical Background

[0002] Bamboo forests are not only an important economic resource but also play a vital role in improving the regional ecological environment. However, due to the past reliance on rainfall, agricultural and forestry activities such as bamboo harvesting and bamboo shoot digging have been widespread and intensive. Coupled with inadequate management of some bamboo forests, this has negatively impacted their quality and yield, resulting in low-yield and inefficient bamboo forests. To improve the ecological quality of bamboo forests and the yield of bamboo products, a large number of low-yield and inefficient forests have been transformed. The main transformation methods include logging, clearing, fertilization, and tending. During the transformation process, due to the complete land clearing and thorough removal of dead branches and fallen leaves, the surface disturbance is significant, resulting in prolonged and large-scale exposure of the surface, significantly reducing its erosion resistance. Furthermore, the transformation period for most low-yield and inefficient bamboo forests largely coincides with the regional rainy season. Under heavy rainfall, the transformed bamboo forest land is highly susceptible to soil erosion and fine gully erosion. Figure 1 Fine gullies are not only important channels for erosion and sediment transport, but also major sources of sediment. Numerous studies both domestically and internationally have shown that fine gully erosion can contribute more than 50% of the total sediment yield from slope erosion. Severe soil erosion leads to the loss of large amounts of organic matter, making the soil more infertile and exacerbating non-point source pollution; on the other hand, it directly affects land productivity and seriously restricts the sustainable development of bamboo resources. Therefore, research on fine gully erosion control technologies in bamboo forest erosion-affected areas is extremely important.

[0003] Numerous technical solutions for gully erosion control have been proposed both domestically and internationally. Domestic research focuses primarily on the Loess Plateau and the Northeast Black Soil region, while solutions specifically for gully erosion control in bamboo forests remain relatively scarce. Traditional gully erosion control measures mainly include vegetation measures and engineering measures. Vegetation measures involve planting vegetation within the gully to reduce runoff energy, primarily using native plants. Engineering measures involve constructing dikes and intercepting drainage ditches. Both methods are costly. Furthermore, vegetation measures face challenges in improving local soil habitats within the gully and the maintenance of suitable plants; engineering measures face difficulties in transporting materials such as cement, sand, and steel, as well as the poor ecological impact of engineering practices. Currently, most bamboo forests are contracted, managed, and operated by individual farmers, and the high cost of gully erosion control discourages farmers from implementing such measures. Furthermore, bamboo forests managed by individual farmers do not meet the conditions for large-scale, systematic implementation of plant and engineering measures. Summary of the Invention

[0004] The purpose of this invention is to provide a comprehensive bamboo resource erosion control system and method for bamboo forest land, which takes into account the ecological nature of the control measures and has low control costs. All materials involved can be sourced locally from bamboo forest land, and the erosion control effect is obvious, significantly improving the ecological environment of forest land erosion.

[0005] A comprehensive bamboo forest erosion control system for gully erosion in poor soil includes an upper catchment runoff dispersion system above the gully catchment area, a gully head erosion control system at the source of erosion in the gully head section, a gully energy dissipation and flow reduction system within the main channel of the gully, an ecological grass gully downstream of the gully outlet, and bamboo dam systems distributed at different elevations along the gully. The upper catchment runoff dispersion system includes a bamboo dike perpendicular to the water flow direction and a simple water storage depression placed above and adjacent to the bamboo dike. The gully head erosion control system includes bamboo retaining walls along the gully wall and a gravel drop layer below the gully wall. The gully energy dissipation and flow reduction system is formed by accumulating bamboo litter at the bottom of the gully upstream of the bamboo dam system and binding it into a cylindrical energy dissipation body with bamboo strips. The ecological grass gully is formed by planting wetland plants within the gully 2-3 meters from the gully outlet.

[0006] Furthermore, the water-dispersing bamboo embankment is formed by digging shallow ditches along contour lines on the slope at intervals of the critical slope length where gully erosion occurs, and then laying bamboo poles flat above the ground elevation; the simple water-retaining depression is formed by manual excavation.

[0007] Furthermore, the formula for calculating the critical slope length for the occurrence of gully erosion is as follows:

[0008]

[0009] Where L is the critical slope length (m) for gully erosion to occur; S is the slope (degrees).

[0010] Furthermore, the width of the water-dispersing bamboo embankment is 8-10cm, the height is 20-30cm, and the length is 1-2m; the length of the simple water storage depression is the same as the length of the water-dispersing bamboo embankment, the shape is an inverted trapezoid, the maximum depth is 15-20cm, and the width is 20-30cm.

[0011] Furthermore, the bamboo retaining wall of the ditch is formed by inserting bamboo poles side by side along the ditch head and wall, perpendicular to the bottom of the ditch and higher than the elevation of the ditch head, and the gravel waterfall layer is formed by piling up gravel below the bamboo retaining wall of the ditch.

[0012] Furthermore, the width of the bamboo retaining wall in the ditch is 10-20cm, the height is 50-80cm, and the length is 20-40cm; the gravel size selected for the gravel waterfall layer is 5-10cm, and the gravel layer thickness is 30-40cm.

[0013] Furthermore, the bamboo trough system is formed by inserting bamboo poles side by side perpendicular to the bottom of the ditch at a turning angle greater than 30°. The width of the bamboo trough system is 10-20cm, the height is 50-80cm, and the length is 20-40cm.

[0014] Furthermore, the channel energy dissipation and flow reduction system is to bind bamboo tips and leaves into cylindrical energy dissipation bodies by binding them with bamboo strips and place them in the channel above the bamboo valley system, wherein the diameter of the cylinder is 10-20cm and the length of the cylinder is 30-50cm.

[0015] Furthermore, the wetland plant is one or a combination of water celery, wild water chestnut, water spinach, and bermudagrass.

[0016] A method for preventing gully erosion in bamboo forest erosion-prone areas by comprehensively utilizing bamboo resources, using the aforementioned system, includes the following steps:

[0017] S1. Constructing a runoff dispersion system for the upper catchment area: A water dispersion bamboo embankment is set up vertically along the direction of water flow above the catchment area of ​​the ditch. A simple water storage depression is arranged close to the water-facing side of the water dispersion bamboo embankment. The bamboo embankment is composed of bamboo poles arranged at intervals. The water storage depression is hydraulically connected to the water dispersion bamboo embankment through the gaps between the bamboo poles.

[0018] S2. Deploy a gully head source erosion prevention system: Set up bamboo retaining walls in the gully head erosion section, and set up a gravel waterfall layer at the bottom of the bamboo retaining walls. The gravel waterfall layer extends to the bottom of the gully to form an anti-erosion base.

[0019] S3. Constructing a ditch energy dissipation system: In the main ditch of the narrow ditch, bamboo forest litter is piled up at the bottom of the ditch in the upstream direction of the bamboo valley system. The bamboo forest litter is bundled into cylindrical energy dissipation bodies using bamboo strips. The cylindrical energy dissipation bodies are arranged at intervals along the extension direction of the ditch.

[0020] S4. Establish an ecological interception system: Modify the ditch within 2-3m downstream of the outlet of the fine ditch, and form an ecological grass ditch by planting wetland plants. The root system of the plants in the ecological grass ditch forms a solidified structure with the soil in the ditch.

[0021] S5. Configure a tiered protection system: Set up a bamboo gully barrier system at different elevations along the gully. The bamboo gully barrier system is connected sequentially with the system constructed in steps S1-S4 along the direction of the gully to form a tiered protection chain from runoff dispersion, gully head protection, gully energy dissipation to ecological interception.

[0022] Compared with existing gully erosion control technologies, this invention has the following significant features and advantages:

[0023] 1. This invention focuses on the prevention and control of gully erosion in bamboo forest erosion-prone areas. The technical materials involved, including bamboo poles, bamboo leaves, bamboo tips, and gravel, can all be sourced locally from bamboo forests, resulting in low-cost prevention and control technologies.

[0024] 2. The materials used in this invention do not involve concrete, steel bars, or traditional water and soil conservation sprayed chemical materials, and the prevention and control technology has high ecological benefits;

[0025] 3. Compared with existing single measures for ditch control, this invention innovates a full-chain ditch control system of "water collection diversion - ditch head stabilization - ditch channel protection - ditch tail adsorption", which has significant control effects. The system utilizes an upper catchment area runoff dispersion system to reduce the accumulation of water from above existing erosion gullies and its continuous scouring, thus curbing the further development of erosion gullies at their source. A gully head erosion control system stabilizes the gully heads with bamboo retaining walls and reduces the jetting energy of water from above with gravel waterfalls. A bamboo dam system intercepts sediment, reduces runoff energy consumption, and deposits nutrients from eroded sediment. A gully energy dissipation and flow reduction system further intercepts sediment, reduces runoff energy consumption, and minimizes runoff scouring of the gully bottom. Bamboo leaves and tips, after being soaked in water, combine with deposited nutrients to form humus, creating a local habitat for natural ecological restoration in the gully. Finally, an ecological grass ditch at the end of the gully further intercepts sediment and absorbs nutrients from eroded sediment, reducing soil erosion while simultaneously controlling non-point source pollution and fully utilizing water resources. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the fine gullies caused by bamboo forest erosion in the wasteland.

[0027] Figure 2 This is a schematic diagram of the structure of a bamboo forest erosion and gully erosion prevention system that comprehensively utilizes bamboo resources, according to an embodiment of the present invention.

[0028] Figure 3 This is a schematic diagram of the runoff dispersion system in the upper water collection area according to an embodiment of the present invention.

[0029] Figure 4 This is a schematic diagram of the gully head erosion prevention and control system according to an embodiment of the present invention.

[0030] Figure 5 This is a schematic diagram of the Zhugufang system according to an embodiment of the present invention.

[0031] Figure 6 This is a schematic diagram of the channel energy dissipation and flow reduction system according to an embodiment of the present invention.

[0032] Figure 7 This is a schematic diagram of an ecological grass ditch according to an embodiment of the present invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Please see Figure 1 and Figure 2 This invention provides a bamboo forest erosion control system that comprehensively utilizes bamboo resources, taking a bamboo forest erosion-prone area as an example. The system includes an upper catchment area runoff dispersion system S10, a gully head source erosion control system S20, a bamboo valley system S30, a gully energy dissipation and flow reduction system S40, and an ecological grass gully S50.

[0035] like Figure 3 As shown, the runoff dispersion system S10 in the upper catchment area includes a bamboo dike S11 perpendicular to the water flow direction and a simple water storage depression S12. Through the runoff dispersion system in the upper catchment area, the accumulation of water above existing erosion gullies and its continuous scouring of the gullies are reduced, thus curbing the further development of erosion gullies at their source.

[0036] The water flow dispersion bamboo dike S11 is made of bamboo poles. It is formed by digging shallow trenches along contour lines on the slope at intervals equal to the critical slope length for gully erosion, and then laying bamboo poles horizontally above the ground elevation. The dike is 8-10 cm wide, 20-30 cm high, and 1-2 m long. The water flow dispersion bamboo dike S11 disperses slope runoff, suppressing the generation of concentrated flows with strong erosive kinetic energy. The formula for calculating the critical slope length for gully erosion is as follows:

[0037]

[0038] Where L is the critical slope length (m) for gully erosion to occur; S is the slope (degrees).

[0039] The simple water-retaining depression S12 is placed above and closely adjacent to the water-dispersing bamboo dike S11, formed by manual excavation. Its length is the same as that of the water-dispersing bamboo dike S11, and its shape is an inverted trapezoid, with a maximum depth of 15-20 cm and a width of 20-30 cm. The simple water-retaining depression S12 further reduces the runoff energy above the water-dispersing bamboo dike, decreases runoff accumulation, and mitigates the impact of the runoff above on the water-dispersing bamboo dike S11.

[0040] like Figure 4As shown, the gully head erosion prevention system S20 includes a bamboo retaining wall S21 along the gully wall and a gravel waterfall layer S22 located below the gully wall. Through the gully head erosion prevention system S20, the bamboo retaining wall S21 stabilizes the head of the existing eroded gully, and the gravel waterfall layer S22 reduces the jet energy of water flowing from above the gully head, thus curbing erosion at its source. The bamboo retaining wall S21 is made of bamboo poles, with a width of 10-20cm, a height of 50-80cm, and a length of 20-40cm, the specific length depending on the width of the gully wall. The bamboo retaining wall S21 stabilizes the head of the existing eroded gully, thus curbing erosion at its source.

[0041] The gravel drop layer S22 is constructed by piling up gravel collected from the bamboo forest area. It is placed below and closely adhered to the bamboo retaining wall S21 of the ditch wall. The selected gravel size is 5-10cm, and the gravel layer thickness is approximately 30-40cm. The gravel drop layer S22 serves two purposes: firstly, it stabilizes the bamboo retaining wall S21 of the ditch wall, and secondly, it reduces the jet energy of water coming from above the ditch head, thus reducing scouring and excavation of the ditch bottom.

[0042] like Figure 5 As shown, the bamboo silt retention system S30 includes bamboo silt retainers distributed at different locations in the ditch. Each bamboo silt retainer is formed by inserting bamboo poles side-by-side perpendicular to the ditch bottom at different elevations, especially where the ditch direction changes significantly (ditch turning angle greater than 30°). The bamboo silt retainers are 10-20cm wide, 50-80cm high, and 20-40cm long. The bamboo silt retention system S30, formed by multiple bamboo silt retainers, achieves the functions of intercepting and storing sediment, reducing runoff energy, and depositing nutrients from eroded sediment.

[0043] like Figure 6 As shown, the channel energy dissipation and flow reduction system S40 includes bamboo tips, bamboo leaves, and other bamboo forest litter placed at the bottom of the channel. The channel energy dissipation and flow reduction system S40 consists of bamboo tips and leaves bound together with bamboo strips into cylindrical energy dissipation bodies, which are placed above the bamboo trough system S30 in the channel. The cylinder diameter is 10-20cm, and the cylinder length is 30-50cm. The channel energy dissipation and flow reduction system S40 further intercepts sediment and reduces runoff energy, minimizing runoff erosion of the channel bottom. Simultaneously, the bamboo leaves and tips, after being soaked in water, combine with deposited nutrients to form humus, creating a local habitat for natural ecological restoration in the channel.

[0044] like Figure 7 As shown, the ecological grass ditch S50 is formed by planting wetland plants in the ditch within 2-3 meters of the outlet of the narrow ditch. The ecological grass ditch S50 further intercepts sediment and absorbs nutrients from eroded sediment, reducing soil erosion while simultaneously controlling non-point source pollution and fully utilizing water resources. The wetland plants are one or a combination of water celery, wild water chestnut, water spinach, and bermudagrass.

[0045] Compared to traditional gully erosion control technologies, this invention innovates a complete gully erosion control system encompassing "catchment diversion - gully head stabilization - gully protection - gully tail absorption": Through an upper catchment runoff dispersion system, runoff accumulation is reduced at the source, curbing continuous erosion of gullies; a gully head erosion control system stabilizes existing erosion heads, inhibiting source erosion; a bamboo gully system and a gully energy dissipation and flow reduction system protect gullies and create local habitats for natural ecological restoration; and ecological grass gullies further intercept sediment and absorb nutrients from eroded sediment. This invention, through a tiered combination of multiple control systems from top to bottom, reduces soil erosion while simultaneously controlling non-point source pollution and fully utilizing water resources.

[0046] This invention also provides a method for preventing gully erosion in bamboo forest erosion-prone areas by comprehensively utilizing bamboo resources. The method employs the aforementioned system and includes the following steps:

[0047] S1. Constructing a runoff dispersion system for the upper catchment area: A water dispersion bamboo embankment is set up vertically along the direction of water flow above the catchment area of ​​the ditch. A simple water storage depression is arranged close to the water-facing side of the water dispersion bamboo embankment. The bamboo embankment is composed of bamboo poles arranged at intervals. The water storage depression is hydraulically connected to the water dispersion bamboo embankment through the gaps between the bamboo poles.

[0048] S2. Deploy a gully head source erosion prevention system: Set up bamboo retaining walls in the gully head erosion section, and set up a gravel waterfall layer at the bottom of the bamboo retaining walls. The gravel waterfall layer extends to the bottom of the gully to form an anti-erosion base.

[0049] S3. Constructing a ditch energy dissipation system: In the main ditch of the narrow ditch, bamboo forest litter is piled up at the bottom of the ditch in the upstream direction of the bamboo valley system. The bamboo forest litter is bundled into cylindrical energy dissipation bodies using bamboo strips. The cylindrical energy dissipation bodies are arranged at intervals along the extension direction of the ditch.

[0050] S4. Establish an ecological interception system: Modify the ditch within 2-3m downstream of the outlet of the fine ditch, and form an ecological grass ditch by planting wetland plants. The root system of the plants in the ecological grass ditch forms a solidified structure with the soil in the ditch.

[0051] S5. Configure a tiered protection system: Install bamboo gully guardrail systems at different elevations along the gully. The bamboo gully guardrail systems are sequentially connected to the systems constructed in steps S1-S4 along the gully, forming a tiered protection chain from runoff dispersion, gully head protection, gully energy dissipation to ecological interception.

[0052] The results of field implementation of this invention in a bamboo forest erosion-prone area in a southwestern province show that: compared with traditional gully erosion control technologies, the materials involved in this invention, including bamboo poles, leaves, tips, and gravel, can all be sourced locally in the bamboo forest, reducing material costs to zero; compared with traditional engineering measures for gully erosion control, the materials used in this invention do not involve concrete, steel bars, or traditional soil and water conservation sprayed chemicals, resulting in a highly ecological control technology; compared with single measures in traditional gully erosion control technologies, this invention significantly increases the sediment interception rate to 75%; after implementation, gully heads are stabilized, and headwater erosion is significantly reduced; the technology significantly increases nutrient content in gullies, with total nitrogen content in sediments increasing to 0.58 g / kg, total phosphorus content increasing to 0.67 g / kg, and organic matter content increasing to 11.24 g / kg, reducing soil erosion while achieving non-point source pollution control and full utilization of water resources; because all materials involved in this technology can be collected locally, farmers have a high willingness to apply this technology.

[0053] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A bamboo forest erosion poor land gully erosion prevention system that comprehensively utilizes bamboo resources, characterized in that, The system includes an upper catchment area runoff dispersion system above the catchment area of ​​the ditch, a gully head erosion control system in the head erosion section of the ditch, a gully energy dissipation and flow reduction system in the main channel of the ditch, an ecological grass gully downstream of the ditch outlet, and a bamboo dam system distributed at different elevations in the ditch. The upper catchment area runoff dispersion system includes a bamboo dike perpendicular to the water flow direction and a simple water storage depression placed above and adjacent to the bamboo dike. The head erosion control system includes a bamboo retaining wall on the gully wall and a gravel waterfall layer below the gully wall. The gully energy dissipation and flow reduction system is formed by accumulating bamboo litter at the bottom of the gully upstream of the bamboo dam system and binding it with bamboo strips into a cylindrical energy dissipation body. The ecological grass gully is formed by planting wetland plants in the gully within 2-3 meters of the ditch outlet. The water-dispersing bamboo embankment is formed by digging shallow ditches along contour lines on the slope at intervals of the critical slope length where gully erosion occurs, and then laying bamboo poles flat above the ground elevation; the simple water-retaining depression is formed by manual excavation. The formula for calculating the critical slope length for gully erosion is as follows: ； Where L is the critical slope length for gully erosion to occur; S is the slope. The bamboo trough system is formed by inserting bamboo poles side by side perpendicular to the bottom of the ditch at a turning angle greater than 30°. The width of the bamboo trough system is 10-20cm, the height is 50-80cm, and the length is 20-40cm.

2. The system for preventing gully erosion on the eroded land with bamboo forest according to claim 1, wherein the bamboo forest is planted on the eroded land. The width of the water-dispersing bamboo embankment is 8-10cm, the height is 20-30cm, and the length is 1-2m; the length of the simple water storage depression is the same as that of the water-dispersing bamboo embankment, the shape is an inverted trapezoid, the maximum depth is 15-20cm, and the width is 20-30cm.

3. The system for preventing gully erosion on the eroded land with bamboo forest according to claim 1, wherein the bamboo forest is planted on the eroded land. The bamboo retaining wall of the ditch is formed by inserting bamboo poles side by side along the ditch head and wall, perpendicular to the bottom of the ditch and higher than the elevation of the ditch head. The gravel waterfall layer is formed by piling up gravel below the bamboo retaining wall of the ditch.

4. The system for preventing gully erosion on the eroded land with bamboo forest according to claim 3, wherein the system further comprises a bamboo forest for preventing gully erosion on the eroded land. The bamboo retaining wall of the ditch is 10-20cm wide, 50-80cm high, and 20-40cm long; the gravel drop layer is made of gravel with a size of 5-10cm and a thickness of 30-40cm.

5. The system for preventing gully erosion on the eroded land with bamboo forest according to claim 1, wherein the system further comprises a bamboo forest for preventing gully erosion on the eroded land. The bamboo forest litter includes bamboo tips and leaves, which are tied together with bamboo strips to form cylindrical energy dissipation bodies and placed in the upper channel of the bamboo valley system. The diameter of the cylinder is 10-20cm and the length of the cylinder is 30-50cm.

6. The bamboo forest erosion and gully erosion prevention system for comprehensively utilizing bamboo resources as described in claim 1, characterized in that, The wetland plants are one or a combination of water celery, wild water chestnut, water spinach, and bermudagrass.

7. A method for preventing gully erosion on eroded land with bamboo forest, characterized in that, The bamboo forest erosion and gully erosion prevention system, which comprehensively utilizes bamboo resources as described in any one of claims 1-6, is used, and the method includes the following steps: S1. Constructing a runoff dispersion system for the upper catchment area: A water dispersion bamboo embankment is set up vertically along the direction of water flow above the catchment area of ​​the ditch. A simple water storage depression is arranged close to the water-facing side of the water dispersion bamboo embankment. The bamboo embankment is composed of bamboo poles arranged at intervals. The water storage depression is hydraulically connected to the water dispersion bamboo embankment through the gaps between the bamboo poles. S2. Deploy a gully head source erosion prevention system: Set up bamboo retaining walls in the gully head erosion section, and set up a gravel waterfall layer at the bottom of the bamboo retaining walls. The gravel waterfall layer extends to the bottom of the gully to form an anti-erosion base. S3. Constructing a ditch energy dissipation system: In the main ditch of the narrow ditch, bamboo forest litter is piled up at the bottom of the ditch in the upstream direction of the bamboo valley system. The bamboo forest litter is bundled into cylindrical energy dissipation bodies using bamboo strips. The cylindrical energy dissipation bodies are arranged at intervals along the extension direction of the ditch. S4. Establish an ecological interception system: Modify the ditch within 2-3m downstream of the outlet of the fine ditch, and form an ecological grass ditch by planting wetland plants. The root system of the plants in the ecological grass ditch forms a solidified structure with the soil in the ditch. S5. Configure a tiered protection system: Set up a bamboo gully barrier system at different elevations along the gully. The bamboo gully barrier system is connected sequentially with the system constructed in steps S1-S4 along the direction of the gully to form a tiered protection chain from runoff dispersion in the upper catchment area, head protection, energy dissipation in the gully channel to ecological interception.

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