Ecological bed and bank fixation structure for mountain stream rivers

Abstract

The present invention relates to an ecological bed and bank fixing structure for mountain streams, which is applicable to the technical field of water conservancy and water ecological governance. The technical solution adopted by the present invention is as follows: An ecological bed and bank fixing structure for mountain streams, characterized in that it has an ecological flow creation structure, which has a bottom plate placed on the river bed. A retaining wall is made on the bottom plate, and a number of top natural stones for forming a water drop on the downstream side are inlaid along the axial direction of the retaining wall at the top of the retaining wall. There are gaps between adjacent top natural stones, and a number of natural stones are piled up on the bottom plates on the upstream and downstream sides of the retaining wall; An upstream ecological erosion prevention structure is provided on the upstream side of the ecological flow creation structure to prevent the water flow from scouring the foundation on the upstream side of the ecological flow creation structure; A downstream ecological erosion prevention structure is provided on the downstream side of the ecological flow creation structure to prevent the water flow from scouring the foundation on the downstream side of the ecological flow creation structure.

Description

Technical Field

[0001] The present invention relates to an ecological riverbed and bank fixing structure for mountain streams, which is applicable to the technical field of water conservancy and water ecological governance. Background Art

[0002] During the flood period, the flow of mountain streams shows the characteristics of sudden increase and decrease, which causes severe scouring of the riverbed and bank slopes, resulting in serious downcutting of the riverbed, increased riverbed bottom slope and instability and collapse of the bank slopes (especially in the concave bank area of the river channel), causing economic losses. To address this problem, currently, overflow weirs are mainly used to control riverbed erosion, and rigid or semi-rigid revetments are used to deal with bank slope scouring problems.

[0003] In the field of overflow weir technology, traditional overflow weirs mainly consist of an upstream flow flat, a flow surface and a downstream stilling basin, which significantly change the natural water flow characteristics and hinder the formation of natural plunge pools, and cannot effectively construct an ecological riverbed with alternating deep pools and shallow shoals. In addition, the full-section blockage of the overflow weir also affects the sediment transport, often causing serious siltation on the upstream side of the weir body, and at the same time, it cannot meet the requirements of fish migration and upstream movement, thus threatening the safety of the ecological system. In the field of revetment technology, due to the severe scouring of the toe of the slope by the flood flow, in order to ensure safety, rigid or semi-rigid revetment technology is often used, which restricts the application of ecological revetment technology, thus affecting the lateral ecological connectivity of the river and ultimately affecting the healthy and stable development of the ecological system.

[0004] Therefore, researching and developing new near-natural riverbed and bank fixing technologies, which can not only maintain the stability of the riverbed and riverbank, but also meet ecological requirements, weaken the main stream scouring, construct fish upstream channels, and ensure the longitudinal continuity and lateral connectivity of the river, has important engineering and scientific significance. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: in view of the above problems, to provide an ecological riverbed and bank fixing structure for mountain streams.

[0006] The technical solution adopted by the present invention is: an ecological riverbed and bank fixing structure for mountain streams, characterized in that: it has an ecological flow creation structure, the ecological flow creation structure has a bottom plate placed on the riverbed, a retaining wall is made on the bottom plate, and a number of top natural stones for forming a plunge pool on the downstream side are inlaid along the axial direction of the retaining wall at the top of the retaining wall, there are gaps between adjacent top natural stones, and a number of natural stones are piled on the bottom plate upstream and downstream of the retaining wall;

[0007] An upstream ecological anti-scouring structure for preventing water flow from scouring the upstream foundation of the ecological flow creation structure is provided on the upstream side of the ecological flow creation structure; a downstream ecological anti-scouring structure for preventing water flow from scouring the downstream foundation of the ecological flow creation structure is provided on the downstream side of the ecological flow creation structure.

[0008] Among the natural stones piled on the upstream bottom plate of the retaining wall, the top of the natural stones is the upstream upper natural stones corresponding to the top natural stones one by one, and the upper part of the upstream upper natural stones is higher than the top surface of the retaining wall.

[0009] Among the natural stones piled on the downstream bottom plate of the retaining wall, the top of the natural stones is the downstream upper natural stones corresponding to the top natural stones one by one, and the upper part of the downstream upper natural stones is higher than the top surface of the retaining wall.

[0010] The natural stones piled on the upstream side bottom plate of the retaining wall include the upstream bottom natural stones embedded in the bottom plate. The upstream bottom natural stones include the upstream outer natural stones and the upstream inner natural stones arranged successively close to the retaining wall, and the upstream upper natural stones are placed on the upstream inner natural stones.

[0011] The natural stones piled on the downstream side bottom plate of the retaining wall include the downstream bottom natural stones embedded in the bottom plate. The downstream bottom natural stones include the downstream inner natural stones close to the retaining wall and the downstream outer natural stones placed at the downstream edge of the bottom plate. There is a downstream middle natural stone between the downstream outer natural stones and the downstream inner natural stones, and the downstream upper natural stones are placed on the downstream inner natural stones.

[0012] The upstream ecological anti-scour structure includes upstream anti-scour upper natural stones, upstream anti-scour bottom natural stones and upstream geotextiles. Among them, the burial depth of the upstream anti-scour bottom natural stones is greater than the maximum calculated scour depth E m , and the particle sizes of the upstream anti-scour upper natural stones and the upstream anti-scour bottom natural stones are greater than the minimum calculated particle size D m ; The upstream side of the upstream geotextile is buried at the bottom of the upstream anti-scour bottom natural stones, and the downstream side is built into the bottom plate.

[0013] The maximum calculated scour depth E m is calculated according to the tail water depth h t , the unit discharge q, the normal supercritical flow depth h e , the sediment particle size D when the cumulative mass fraction is 90% 90 ;

[0014]

[0015] The minimum riprap particle size D m is determined by the maximum flow velocity V max , the pebble density ρ s for, the water density ρ w , the turbulent flow influence coefficient E i and the slope correction coefficient K; Among them, the turbulent flow influence coefficient E i is between 0.86 and 1.28; The maximum flow velocity V max is calculated from the cross-sectional average flow velocity V0, the pebble water-blocking area A s and the cross-sectional area A ges ;

[0016]

[0017] The downstream ecological scouring prevention structure includes upstream natural stones of the downstream scouring prevention layer, downstream natural stones of the downstream scouring prevention layer, and downstream geotextiles. The downstream natural stones of the downstream scouring prevention layer include inner natural stones of the downstream scouring prevention layer and outer natural stones of the downstream scouring prevention layer. The inner natural stones of the downstream scouring prevention layer, the outer natural stones of the downstream scouring prevention layer, and the upstream natural stones of the downstream scouring prevention layer form a triangular stable structure, where the buried depth of the downstream natural stones of the downstream scouring prevention layer is greater than the maximum calculated scouring depth E m , and the particle size of the downstream natural stones of the downstream scouring prevention layer is greater than the minimum calculated particle size D m ; The upstream side of the downstream geotextile is built into the bottom plate, and the downstream side is buried at the bottom of the downstream natural stones of the downstream scouring prevention layer;

[0018] The maximum calculated scouring depth E m is calculated according to the tail water depth h t , the unit discharge q, the normal supercritical flow depth h e , the sediment particle size D when the cumulative mass fraction is 90%; 90 Calculation;

[0019]

[0020] The minimum loose stone particle size D m is determined by the maximum flow velocity V max , the pebble density ρ s for, the water density ρ w , the turbulent flow influence coefficient E i and the slope correction coefficient K; among them, the turbulent flow influence coefficient E i is between 0.86 and 1.28; the maximum flow velocity V max is calculated from the cross-sectional average flow velocity V0, the pebble water-blocking area A s and the cross-sectional area A ges Calculation;

[0021]

[0022]

[0023] In the straight section of the river channel, the ecological flow generation structure is arranged in a parabolic shape on the plane. The top of the parabola protrudes upstream of the river, and the included angles between the two sides of the parabola and the tangent of the river bank are between 30° and 40°. The two endpoints of the parabola are inserted into the measured river bank;

[0024] The top-layer natural stones from the two endpoints of the parabola to the top-layer natural stones at the vertex of the parabola are in a slope; the elevation of the top-layer natural stones at the endpoints is 50 cm higher than the normal water level, and the elevation of the top-layer natural stones at the vertex of the parabola is the same as the normal water level.

[0025] The planar spacing S between two adjacent ecological flow - creating structures along the water flow direction V Calculated according to the river channel slope i, the elevation difference between two adjacent ecological flow - creating structures is about 30 cm;

[0026] S V = 8.2513i -0.9799 。

[0027] In the curved section of the river channel, the ecological flow - creating structures are arranged in a "J" - shaped curve in the plane. One end point of the ecological flow - creating structure is inserted into the river bank, and the other end point is inserted into the floodplain. The included angle between the "J" - shaped curve and the tangent of the river bank is between 30° and 40°.

[0028] The elevation of the top - layer natural stone at the vertex of the "J" - shaped curve is about 10 cm lower than the normal water level.

[0029] The beneficial effects of the present invention are as follows: In the ecological flow - creating structure of the present invention, natural stones are inlaid on the concrete bottom plate and retaining wall. The top - layer natural stones are arranged at intervals and form a waterfall with the upstream and downstream natural stones, and the natural stones on the downstream side are arranged staggeredly to form a diverse flow pattern. In the present invention, an upstream ecological erosion - prevention structure is provided upstream of the ecological flow - creating structure to prevent the erosion of the foundation on the upstream side of the ecological flow - creating structure by the water flow; a downstream ecological erosion - prevention structure is provided downstream of the ecological flow - creating structure to prevent the erosion of the foundation on the downstream side of the flow - creating structure by the water flow.

[0030] The present invention takes into account the near - natural ecological method for fixing the river bed and the river bank of mountain - stream rivers, solves the ecological restoration technical problem of river - bed and bank - slope erosion, is beneficial to dispersing the main flow, weakening the erosion of the main flow on the river bed and bank - slope, and constructing an ecological river - bed structure with alternating deep pools and shallow beaches, provides a multi - pore refuge and breeding space and migration channels for aquatic animals, and at the same time ensures the ecological base flow, longitudinal ecological continuity and lateral connectivity of the river, and has significant economic, social and environmental benefits. Brief Description of the Drawings

[0031] Figure 1 It is a sectional view of the embodiment.

[0032] Figure 2 It is a schematic diagram of the setting of geotextile for the erosion - prevention structure in the embodiment.

[0033] Figure 3 It is a schematic diagram of the upstream and downstream safety spaces in the embodiment.

[0034] Figure 4 It is a schematic diagram of the included angle between the embodiment and the river bank.

[0035] Figure 5 It is a downstream side view (sectional view of the 1 - 1 section) of the embodiment in the straight river section.

[0036] Figure 6 It is a downstream side view (sectional view of the 2 - 2 section) of the embodiment in the curved river section.

[0037] Figure 7 Schematic diagram of the relationship between the top elevation and normal water level and low water level in the straight river section for the embodiment.

[0038] Figure 8 Schematic diagram of the relationship between the top elevation and normal water level and low water level in the meandering river section for the embodiment.

[0039] 10. Upstream ecological erosion prevention structure; 11. Upstream upper-layer natural stones for erosion prevention; 12. Upstream lower-layer natural stones for erosion prevention; 13. Upstream geotextile; 20. Ecological flow creation structure; 21. Inverted "T"-shaped concrete foundation; 22. Upstream upper-layer natural stones; 23. Upstream inner-layer natural stones; 24. Upstream outer-layer natural stones; 25. Top-layer natural stones; 26. Downstream upper-layer natural stones; 27. Downstream inner-layer natural stones; 28. Downstream middle-layer natural stones; 29. Downstream outer-layer natural stones; 30. Downstream ecological erosion prevention structure; 31. Downstream upper-layer natural stones for erosion prevention; 32. Downstream inner-layer natural stones for erosion prevention; 33. Downstream outer-layer natural stones for erosion prevention; 34. Downstream geotextile; 40. Calculated maximum scour depth; 50. Normal water level; 51. Low water level; 60. Safety space I; 61. Safety space II; 62. Fish migration channel; 70. Main flow direction; 80. Endpoint I where the structure inserts into the riverbank; 81. Endpoint II where the structure inserts into the riverbank; 82. Endpoint where the structure inserts into the floodplain. Detailed implementation method

[0040] As Figure 1 shown, this embodiment is an ecological bed and bank fixation structure for a mountain stream river, including an upstream ecological erosion prevention structure 10, an ecological flow creation structure 20, and a downstream ecological erosion prevention structure 30. The upstream ecological erosion prevention structure 10 is composed of upstream upper-layer natural stones 11 for erosion prevention, upstream lower-layer natural stones 12 for erosion prevention, and an upstream geotextile 13, which is used to prevent the erosion of the foundation on the upstream side of the flow creation structure by water flow; the ecological flow creation structure 20 is mainly an inverted "T"-shaped concrete foundation 21 inlaid with natural stones. The top-layer natural stones 25 inlaid on the top of the concrete foundation are arranged at intervals and form a drop with the upstream and downstream natural stones, and at the same time provide a channel for fish migration. The downstream natural stones are arranged staggered to form a diverse flow pattern; the downstream ecological erosion prevention structure 30 is a "triangle"-shaped stable structure formed by stacking natural stones, and a downstream geotextile 34 is provided to protect the foundation on the downstream side of the flow creation structure from the erosion of water flow.

[0041] In this embodiment, the upstream ecological erosion prevention structure 10 includes upstream upper-layer natural stones 11 for erosion prevention, upstream lower-layer natural stones 12 for erosion prevention, and an upstream geotextile 13. The burial depth of the upstream lower-layer natural stones 12 for erosion prevention needs to be greater than the maximum calculated scour depth E m 40, and the particle sizes of the upstream upper-layer natural stones 11 for erosion prevention and the upstream lower-layer natural stones 12 for erosion prevention need to be greater than the minimum calculated particle size D m; The upstream side of the upstream geotextile 13 is buried at the bottom of the upstream scour prevention bottom layer of natural stones 12, with a surplus length of not less than 30 cm. The downstream side is built into the inverted "T" - shaped concrete foundation 21 of the ecological flow - creating structure, and the built - in length is not less than 50 cm (see Figure 2 ). The technical parameters of the upstream geotextile 13 should preferably be 500 g / m 2 .

[0042] In this example, the ecological flow - creating structure includes an inverted "T" - shaped concrete foundation 21 and natural stones, and has the characteristics of drop - water aeration, co - existence of rapid and slow flows, multi - void habitats, and longitudinal continuity. The inverted "T" - shaped concrete foundation 21 has a bottom plate placed on the riverbed, and a retaining wall is made on the bottom plate.

[0043] In this embodiment, upstream upper - layer natural stones 22 and upstream bottom - layer natural stones are arranged on the bottom plate upstream of the retaining wall. The upstream bottom - layer natural stones include upstream inner - layer natural stones 23 close to the retaining wall and upstream outer - layer natural stones 24 located on the outer side. The particle size of the natural stones is between 20 and 30 cm. In this example, the upstream inner - layer natural stones 23 are embedded in the bottom plate at intervals of 5 - 10 cm, and the embedding depth is about 5 cm; the upstream outer - layer natural stones 24 are embedded in the bottom plate at intervals of 30 cm, and the embedding depth is about 5 cm; the upstream upper - layer natural stones 22 are placed stably on the upstream inner - layer natural stones 23 and arranged at intervals of 30 cm. The upper - layer natural stones 22, upstream inner - layer natural stones 23, and upstream outer - layer natural stones 24 form a safety space Ⅰ60 with multiple access channels with a width of 5 - 10 cm through natural stacking, ensuring a refuge for fish during flood periods or when the flow is rapid (see Figure 3 ).

[0044] In this embodiment, downstream upper - layer natural stones 26 and downstream bottom - layer natural stones are arranged on the bottom plate downstream of the retaining wall. The downstream bottom - layer natural stones include downstream inner - layer natural stones 27 close to the retaining wall and downstream outer - layer natural stones 29 placed at the downstream edge of the bottom plate. There are downstream middle - layer natural stones 28 between the downstream outer - layer natural stones and the downstream inner - layer natural stones. The particle size of the natural stones is between 20 and 30 cm. In this example, the downstream inner - layer natural stones 27 are embedded in the bottom plate at intervals of 5 - 10 cm, and the embedding depth is about 5 cm; the downstream middle - layer natural stones 28 are embedded in the bottom plate at intervals of 30 cm; the downstream outer - layer natural stones 29 are arranged along the edge of the bottom plate and embedded in the bottom plate at intervals of 30 cm, and the embedding depth is about 5 cm. The downstream upper - layer natural stones 26 are placed stably on the downstream inner - layer natural stones 27 and arranged at intervals of 30 cm. The downstream upper - layer natural stones 26, downstream inner - layer natural stones 27, downstream middle - layer natural stones 28, and downstream outer - layer natural stones 29 form a safety space Ⅱ61 with multiple channels with a width of 5 - 10 cm through natural stacking, ensuring a refuge for fish during flood periods or when the flow is rapid (see Figure 3 ).

[0045] In this example, a layer of top-layer natural stone 25 is embedded at intervals of 30 cm along the axial direction of the retaining wall at the top of the retaining wall, with an embedding depth of about 5 cm. The top-layer natural stone 25 corresponds to the upstream upper-layer natural stone 22 and the downstream upper-layer natural stone 26 one by one, forming a straight line, and the top-layer natural stone 25 is naturally embedded between the upstream upper-layer natural stone 22 and the downstream upper-layer natural stone 26. The three play the role of mutual shielding and reinforcement, and form a waterfall on the downstream side of the top-layer natural stone 25, which is conducive to the creation of diversified flow patterns and aeration and oxygenation. In addition, the water flowing through the gap of about 30 cm width between adjacent top-layer natural stones 25 is further mixed with the waterfall to form a near-natural turbulent field, creating an induction velocity zone for fish migration, attracting fish to approach, and serving as a fish migration channel 62.

[0046] In this embodiment, the downstream ecological anti-scouring structure 30 includes a downstream anti-scouring upper layer of natural stone 31, a downstream anti-scouring bottom layer of natural stone and a downstream geotextile 34. The downstream anti-scouring bottom layer of natural stone includes a downstream anti-scouring inner layer of natural stone 32 and a downstream anti-scouring outer layer of natural stone 33. The downstream anti-scouring upper layer of natural stone 31, the downstream anti-scouring inner layer of natural stone 32 and the downstream anti-scouring outer layer of natural stone 33 are stacked to form a "triangle" stable structure to ensure that the entire structure meets the requirements of stability, anti-scouring, anti-overturning, etc. The burial depth of the downstream anti-scouring inner layer of natural stone 32 and the downstream anti-scouring outer layer of natural stone 33 is greater than the maximum calculated scouring depth E m The particle size of the downstream anti-collision inner layer natural stone 32 and the downstream anti-collision outer layer natural stone 33 must be greater than the minimum calculated particle size D m The upstream side of the downstream geotextile 34 is built into the bottom plate of the concrete foundation 21 of the ecological flow-making structure, with a length of not less than 50 cm, and the downstream side is buried in the bottom of the downstream anti-scouring inner layer natural stone 32 and the downstream anti-scouring outer layer natural stone 33, with a surplus length of not less than 30 cm. The technical parameters of the downstream geotextile 34 should be 500g / m 2 .

[0047] The maximum calculated scour depth E in this embodiment m 40 According to the tailwater depth h t , single width flow q, normal supercritical flow water depth h e , sediment particle size D when the cumulative mass fraction is 90% 90 Calculation formula (1).

[0048]

[0049] Minimum loose stone particle size D m By the maximum flow rate V max , pebble density ρ s is the water density ρ w , Turbulence influence coefficient E i And the slope correction coefficient K determines the formula (2); where the turbulence influence coefficient E i Between 0.86 and 1.28; maximum flow rate Vmax From the cross-sectional average velocity V0, the water-blocking area A of the pebbles s and the cross-sectional water area A ges Calculation formula (3).

[0050]

[0051] As Figure 4 and Figure 5 shown, in the straight section of the river channel, the plane of the ecological flow creation structure 20 is parabolic, the top of the parabola bulges upstream of the river channel and faces the main flow 70 directly, the included angles between the two sides of the parabola and the tangent of the river bank are between 30° and 40°, the two endpoints of the parabola (endpoints Ⅰ, Ⅱ 80, 81 where the structure inserts into the river bank) insert into the river bank, the top natural stones 25 at the endpoints to the top natural stones 25 at the vertex of the parabola form a local slope, the elevation of the top natural stones at the endpoints is 50 cm higher than the normal water level, and the elevation of the top natural stones 25 at the vertex of the parabola is the same as the normal water level. In this example, the parabolic structure can effectively decompose the main flow, avoid the concentrated scouring of the main flow on the river bed, thus preventing the further erosion and downcutting of the river bed, making the river bed gradually recover to a healthy state, and forming a certain siltation area at the river bank, strengthening the revetment foundation, and providing stable hydrodynamic conditions for the subsequent layout of ecological measures.

[0052] As Figure 6 shown, in the curved section of the river channel, the plane of the ecological flow creation structure 20 is a "J"-shaped curve. One endpoint of this ecological flow creation structure 20 (endpoint Ⅰ 80 where the structure inserts into the river bank) inserts into the river bank, and the other endpoint (endpoint 82 where the structure inserts into the floodplain) inserts into the floodplain. The included angle between the structure curve and the tangent of the river bank is between 30° and 40°. In this example, the "J"-shaped structure disperses the main flow at the bend, restores the eroded river bed and strengthens the revetment foundation.

[0053] As Figure 7 shown, in the straight section of the river reach, the ecological river bed and bank fixation structures in this example should be continuously arranged. The elevation of the top natural stones at the vertex of the parabola is the same as the normal water level 50. On the premise of not affecting flood discharge, it is beneficial to construct an ecological river bed structure with alternating deep pools and shallow beaches. The plane spacing S between two adjacent ecological flow creation structures 20 V is calculated according to the river channel slope i by formula (4). The height difference between two adjacent ecological flow creation structures 20 is about 30 cm, which can ensure that there is still a shallow water area of about 15 cm on the downstream side of the ecological flow creation structure 21 at the low water level 51, thus maintaining the longitudinal ecological continuity.

[0054] S V = 8.2513i -0.9799 (4)

[0055] As Figure 8As shown in the figure, in the curved section of the river reach, the ecological bed-fixing and bank-fixing structures in this embodiment can be arranged individually. The elevation of the top natural stones at the vertex of the "J" - shaped curve is about 10 cm lower than the normal water level by 50, protecting the riverbed and riverbank while minimizing the impact on the flow regime of the curved river reach as much as possible; storing a certain amount of water during the dry season to ensure the ecological base flow.

[0056] In summary, this embodiment realizes the ecological restoration of the riverbed and revetment in both straight and curved river reaches. By means of continuous arrangement in the straight river reach and local arrangement in the curved river reach, it ensures the ecological base flow, longitudinal ecological continuity and lateral connectivity of the river, which is conducive to the systematic restoration of the basin ecological environment.

Claims

1. An ecological bed and bank fixing structure for mountainous streams, characterized in that: It has an ecological flow - creating structure. The ecological flow - creating structure has a bottom plate placed on the riverbed. A water - retaining weir is made on the bottom plate. Along the axial direction of the water - retaining weir, several top - layer natural stones for forming a hydraulic jump on the downstream side are inlaid on the top of the water - retaining weir. There are gaps between adjacent top - layer natural stones. Several natural stones are piled on the bottom plates upstream and downstream of the water - retaining weir. An upstream ecological erosion - prevention structure for preventing water flow from scouring the upstream foundation of the ecological flow - creating structure is arranged on the upstream side of the ecological flow - creating structure; a downstream ecological erosion - prevention structure for preventing water flow from scouring the downstream foundation of the ecological flow - creating structure is arranged on the downstream side of the ecological flow - creating structure. The upstream ecological erosion prevention structure includes an upper layer of natural stones for upstream erosion prevention, a bottom layer of natural stones for upstream erosion prevention, and an upstream geotextile. The burial depth of the bottom layer of natural stones for upstream erosion prevention is greater than the maximum calculated scour depth. , and the particle sizes of the upper layer of natural stones for upstream erosion prevention and the bottom layer of natural stones for upstream erosion prevention are greater than the minimum calculated particle size. ; The upstream side of the upstream geotextile is buried at the bottom of the bottom layer of natural stones for upstream erosion prevention, and the downstream side is built into the bottom plate. The maximum calculated scouring depth According to the tail water depth , the unit discharge q, the normal supercritical flow depth , the sediment particle size when the cumulative mass fraction is 90% Calculate; The minimum calculated particle size is determined by the maximum flow velocity , the pebble density , the water density , the turbulent flow influence coefficient and the slope correction coefficient K; wherein the turbulent flow influence coefficient is between 0.86 and 1.28; the maximum flow velocity is calculated from the cross-sectional average flow velocity , the water-blocking area of the pebbles and the water-crossing area ; ； The downstream ecological scour prevention structure includes the upper-layer natural stones for downstream scour prevention, the bottom-layer natural stones for downstream scour prevention, and the downstream geotextile. The bottom-layer natural stones for downstream scour prevention include the inner-layer natural stones for downstream scour prevention and the outer-layer natural stones for downstream scour prevention. The inner-layer natural stones for downstream scour prevention, the outer-layer natural stones for downstream scour prevention, and the upper-layer natural stones for downstream scour prevention form a triangular stable structure, where the burial depth of the bottom-layer natural stones for downstream scour prevention is greater than the maximum calculated scour depth , and the particle size of the bottom-layer natural stones for downstream scour prevention is greater than the minimum calculated particle size ; the upstream side of the downstream geotextile is built into the bottom plate, and the downstream side is buried at the bottom of the bottom-layer natural stones for downstream scour prevention; In the straight section of the river channel, the ecological flow - creating structure is arranged in a parabolic shape in plan. The top of the parabola bulges towards the upstream of the river. The included angles between the tangents of the two sides of the parabola and the riverbank are between 30° and 40°. The two end points of the parabola are inserted into the two sides of the riverbank. The top - layer natural stones from the two end points of the parabola to the top - layer natural stone at the vertex of the parabola form a slope. The elevation of the top - layer natural stones at the end points is 50 cm higher than the normal water level, and the elevation of the top - layer natural stones at the vertex of the parabola is the same as the normal water level. The planar spacing S between two adjacent ecological flow-making structures along the water flow direction V Calculated according to the river channel slope i, the height difference between two adjacent ecological flow-making structures is 30 cm; 。 2. The ecological bed and bank fixing structure for mountain streams according to claim 1, characterized in that: Among the natural stones piled on the upstream - side bottom plate of the water - retaining weir, the top ones are upstream upper - layer natural stones corresponding one - by - one to the top - layer natural stones, and the upper parts of the upstream upper - layer natural stones are higher than the top surface of the water - retaining weir. Among the natural stones piled on the downstream - side bottom plate of the water - retaining weir, the top ones are downstream upper - layer natural stones corresponding one - by - one to the top - layer natural stones, and the upper parts of the downstream upper - layer natural stones are higher than the top surface of the water - retaining weir.

3. The ecological bed and bank fixing structure for mountain streams according to claim 2, characterized in that: The natural stones piled on the upstream - side bottom plate of the water - retaining weir include upstream bottom - layer natural stones inlaid on the bottom plate. The upstream bottom - layer natural stones include an upstream outer - layer natural stone and an upstream inner - layer natural stone arranged successively close to the water - retaining weir. The upstream upper - layer natural stones are placed on the upstream inner - layer natural stones.

4. The ecological bed and bank fixing structure for mountain streams according to claim 2, characterized in that: The natural stones piled on the downstream - side bottom plate of the water - retaining weir include downstream bottom - layer natural stones inlaid on the bottom plate. The downstream bottom - layer natural stones include a downstream inner - layer natural stone close to the water - retaining weir and a downstream outer - layer natural stone placed at the downstream edge of the bottom plate. A downstream middle - layer natural stone is arranged between the downstream outer - layer natural stone and the downstream inner - layer natural stone. The downstream upper - layer natural stones are placed on the downstream inner - layer natural stones.

5. The ecological bed and bank fixing structure for mountain streams according to claim 1, characterized in that: In the curved section of the river channel, the ecological flow - creating structure is arranged in a "J” - shaped curve in plan. One end point of the ecological flow - creating structure is inserted into the riverbank, and the other end point is inserted into the floodplain. The included angle between the "J” - shaped curve and the tangent of the riverbank is between 30° and 40°.

6. The ecological bed and bank fixation structure for mountain streams according to claim 5, characterized in that: The elevation of the top - layer natural stone at the vertex of the "J” - shaped curve is 10 cm lower than the normal water level.

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