Small and medium scale meandering river multi-stage biological habitat system and construction method thereof

Abstract

The application discloses a small and medium scale meandering river multi-stage biological habitat system, and the river has a convex bank and a concave bank which are oppositely arranged, and further comprises: a water-permeable flow guide unit which is arranged on the convex bank of the river and extends into the river, and is used for guiding the water flow direction and reducing the water flow speed; a deep pool habitat unit which is formed downstream of the concave bank opposite to the water-permeable flow guide unit; and a shoal habitat unit which is formed downstream of the convex bank on the leeward side of the water-permeable flow guide unit; wherein the deep pool habitat unit is arranged with a second habitat substrate group, and the surface of the shoal habitat unit is arranged with a first habitat substrate group. The application further discloses a construction method of the small and medium scale meandering river multi-stage biological habitat system, the water flow is guided and utilized by the water-permeable flow guide unit, the deep pool habitat unit and the shoal habitat unit are shaped, the interference to the natural environment is small, and the multi-stage biological habitat system is constructed through the arrangement of the second habitat substrate group and the first habitat substrate group.

Description

Technical Field

[0001] This invention belongs to the field of river ecological restoration engineering technology, specifically involving a multi-level biological habitat system in a meandering river channel at a small to medium scale, and also involves a method for constructing such a system. Background Technology

[0002] River ecological restoration is a crucial step in restoring river biodiversity and maintaining ecosystem health. Through comprehensive measures such as introducing ecological purification technologies, native species, and eco-friendly bank protection materials, it aims to rebuild and enrich river ecosystems, enhance biodiversity, improve water quality, and improve the river landscape. In the management of small- to medium-scale meandering rivers, constructing suitable habitats is one of the core objectives. Currently, relevant technologies mainly include riverbed sediment improvement, artificial fish nest placement, ecological bank protection construction, and engineering measures to create deep-pool-shallow-shoal sequences.

[0003] In existing technologies, a common practice is to use traditional rigid diversion and water-blocking structures such as groynes or weirs to alter local flow patterns and create areas of varying depths. However, these structures are mostly built of concrete or masonry, have poor permeability, and severely obstruct the longitudinal continuity of water flow and the migration channels for benthic organisms, resulting in significant ecological disturbance. Furthermore, these structures are usually designed for flood control or bank stabilization, lacking specific consideration for the ecological functions of the habitat, and the resulting water flow conditions and pool / shoal morphologies are often simplistic and unnatural.

[0004] Another common technique is direct terrain modification, which involves using mechanical equipment to excavate deep pools and create shallow areas in the river channel, and then dumping materials such as pebbles and boulders. While this method can quickly form physical structures, it has significant drawbacks: First, the resulting hydraulic conditions and habitat structures are often static and isolated, not coupled with the natural hydrodynamic processes of the river channel, leading to unstable structures that are easily eroded or silted up by floods, resulting in high maintenance costs. Second, the placement of substrates such as pebbles often lacks scientific design, frequently employing uniform particle size or random placement without being finely configured according to microhabitat conditions such as flow velocity and water depth, thus providing limited types of ecological niches and making it difficult to form a functionally complex habitat system.

[0005] Therefore, in the ecological restoration practice of small- to medium-scale meandering waterways, there is still a lack of technical methods that can adapt to and cleverly utilize natural hydraulic processes, achieve active and stable habitat shaping with minimal ecological disturbance, and systematically construct multi-level composite habitats with diverse functions, stable structures, and strong self-sustaining capabilities. Summary of the Invention

[0006] To address the aforementioned deficiencies in existing technologies, this invention aims to provide a multi-level biological habitat system in a meandering river channel at a small to medium scale and a method for its construction. To achieve the above objectives, the present invention adopts the following technical solution: A multi-level biological habitat system in a meandering, small-to-medium-scale river channel, with opposing convex and concave banks, comprising: The permeable diversion unit is installed on the convex bank of the river and extends into the river to guide the upstream mainstream to the concave bank; it is also used to reduce the water flow velocity on the back side of the permeable diversion unit to promote siltation. The Deep Pool Habitat Unit is located downstream of the concave bank opposite the permeable diversion unit and is naturally formed by the guided water flow scouring the concave bank and the riverbed below it. The shallow water habitat unit is located on the convex bank area on the backwater side of the permeable diversion unit and is naturally formed by siltation. The deep pool habitat unit is equipped with a second habitat substrate group, while the shallow beach habitat unit is equipped with a first habitat substrate group on its surface.

[0007] The permeable diversion unit is a wooden pile diversion groyne. The axis of the wooden pile diversion groyne extends from the convex bank into the river channel and points downstream. The angle between the axis and the tangent of the convex bank is 15° to 60°.

[0008] The wooden pile diversion groynes consist of multiple rows of wooden piles extending along the axial direction. The rows of wooden piles are parallel to each other, and the wooden piles in each row are spaced apart. The lower ends of the wooden piles located in the river channel are fixed to the riverbed by foundation fixing components, while the lower ends of the wooden piles located on the convex bank slope are directly buried in the slope soil.

[0009] The foundation fixing components are precast concrete anchor blocks, with steel sleeves pre-embedded at the top of the precast concrete anchor blocks. The lower end of the wooden pile is anchored in the steel sleeve, and the precast concrete anchor blocks are laid on the riverbed surface.

[0010] The basic fixing components are rows of gabions, which are laid on the riverbed surface, and the lower ends of the wooden piles are inserted and anchored inside the rows of gabions.

[0011] The deep pool habitat unit is equipped with gabion anchors, which are located at the bottom and / or slope of the deep pool habitat unit.

[0012] The second habitat matrix group includes several large rock piles located on the gentle slope at the edge of the deep pool habitat unit, with the large rocks having a diameter of more than 50 centimeters.

[0013] The first habitat substrate group includes flat pebbles with a diameter of 30-50 cm and smaller pebbles with a diameter of 10-20 cm. The flat pebbles with a diameter of 30-50 cm are arranged into multiple pebble strips parallel to the shoreline of the convex bank. The pebble strips are located in the shallow water habitat unit where the surface current velocity is greater than or equal to 0.5 m / s during the normal water period. The smaller pebbles with a diameter of 10-20 cm are aggregated into multiple pebble clusters. Each pebble cluster has a diameter of 1 to 3 meters. The pebble clusters are located in the shallow water habitat unit where the surface current velocity is less than 0.5 m / s during the normal water period.

[0014] When laying out the first habitat substrate group to form the pebble belt and pebble cluster, based on pebbles with a particle size of 30-50 cm or 10-20 cm as the main framework, 10% to 20% by volume of small gravel with a particle size of 2 to 5 cm is mixed into the pores of the main framework.

[0015] A method for constructing a multi-level biological habitat system in a meandering river channel at a small to medium scale includes the following steps: Step 1: Plan the diversion zone and the siltation zone on the convex bank, and plan the target concave bank scour zone on the concave bank; Step 2: Place the precast concrete anchor blocks on the riverbed surface according to the design position and partially embed them into the riverbed. Anchor the lower end of the wooden piles located in the riverbed to the pre-embedded steel sleeve of the precast concrete anchor blocks. Bury the lower end of the wooden piles located on the convex bank slope directly in the slope soil to form a permeable diversion unit that extends into the river based on the diversion area. Step 3: Place a gabion anchor in the center of the target concave bank scour area. The target concave bank scour area will form a deep pool habitat unit under the natural scour of the water flow, and the convex bank siltation area will form a shallow beach habitat unit after the accumulation of silt. Step 4: Within the shallow water habitat unit, measure the surface flow velocity during the normal water period. Divide the area with a flow velocity higher than 0.5 m / s into the high flow velocity zone of the shallow water, and divide the area with a flow velocity lower than 0.5 m / s into the low flow velocity zone of the shallow water. In the high flow velocity zone of the shallow water, lay multiple pebble strips parallel to the shoreline of the convex bank. In the low flow velocity zone of the shallow water, lay multiple pebble clusters. On the gentle slope at the edge of the deep pool habitat unit, lay multiple large stone piles.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. Eco-friendly and process-integrated: The use of permeable diversion units (such as groynes with wooden piles) not only guides the water flow but also maximizes the protection of the longitudinal continuity of the water flow and the permeability of the bottom sediment, minimizing ecological disturbance. This invention conforms to and enhances the inherent water flow scouring and deposition patterns of meandering river channels, shaping habitats by actively guiding natural hydraulic processes. This results in a highly integrated pool and beach system with the river's dynamic environment, creating a natural and stable structure.

[0017] 2. By simultaneously generating two core units, deep pools and shallow beaches, through a diversion structure and with the addition of a refined substrate, a multi-level composite habitat system is formed, covering overwintering, refuge, spawning, foraging, and juvenile rearing, from rapid to slow flow and from deep to shallow water, significantly improving the ecological benefits per unit of project.

[0018] 3. Stable structure and strong self-sustaining ability: The lower end of the wooden piles located in the river channel is fixed to the riverbed through foundation fixing components, which strengthens the fixing effect of the wooden piles and makes the structure of the permeable diversion unit more stable; the deep pool morphology is guided and stabilized by the gabion anchor; the constructed habitat system benefits from the coupling with the natural water flow process, and has a strong self-sustaining and regeneration ability, reducing long-term maintenance costs.

[0019] 4. Refined Configuration and Maximization of Niche: Based on the surface flow velocity of the shallow water habitat unit during the normal water period, the shallow water habitat unit is divided into a high-velocity zone and a low-velocity zone. In the high-velocity zone, a pebble strip parallel to the shoreline of the convex bank is laid out, and in the low-velocity zone, multiple pebble clusters are laid out. This makes the habitat substrate no longer a simple filler, but a functional engineering structure that can create diverse microhabitats, maximize niche capacity, and specifically meet the needs of target organisms, greatly improving the quality of the habitat and biological carrying capacity. Attached Figure Description

[0020] Figure 1 A schematic diagram of the structure of a multi-level biological habitat system in a meandering river channel at a small to medium scale; Figure 2 A schematic diagram of a structure in which wooden piles are fixed by foundation fixing components; Figure 3 A cross-sectional schematic diagram illustrating the principle of deep pool-shallow shoal topography (cut along the direction of water flow); Figure 4 A schematic diagram of the layout for the first habitat substrate group; Among them, 1-concave bank; 2-permeable diversion unit; 21-wooden pile; 3-convex bank; 4-deep pool habitat unit; 5-shallow beach habitat unit; 61-first habitat substrate group; 62-second habitat substrate group; 7-gabion anchor solid; 8-foundation fixing component. Detailed Implementation

[0021] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of this invention. Example 1:

[0022] like Figure 1As shown, a multi-level biological habitat system in a meandering river channel at a small to medium scale includes a permeable diversion unit 2, a deep pool habitat unit 4, and a shallow beach habitat unit 5. The permeable diversion unit 2 is located in a pre-designated diversion area on the convex bank 3 (such as slightly upstream of the bend). The main structure of the permeable diversion unit 2 extends from the convex bank 3 into the river channel and points downstream, thereby guiding the water flow to the concave bank 1 on the opposite bank, thus shaping the deep pool habitat unit 4 and the shallow beach habitat unit 5. The guided water flow continuously scours the concave bank 1 and the riverbed below, naturally forming the deep pool habitat unit 4 in the downstream area of ​​the concave bank 1. When the water flows through the permeable diversion unit 2 into its back side, the flow velocity will be significantly reduced, causing sediment from upstream to accumulate in the area of ​​the convex bank 3, naturally forming the shallow beach habitat unit 5.

[0023] The surface of the shallow beach habitat unit 5 is provided with a first habitat substrate group 61, and the deep pool habitat unit 4 is provided with a second habitat substrate group 62. Along the direction of water flow, the deep pool habitat unit 4, the shallow beach habitat unit 5 and the substrate groups on them together constitute a multi-level habitat sequence with continuous hydraulic conditions and complementary ecological functions.

[0024] In some embodiments, such as Figure 2 As shown, the permeable diversion unit 2 is preferably a wooden pile groyne. The axis of the wooden pile groyne extends from the convex bank 3 into the river channel and points downstream, with an angle of 15° to 60° with the tangent of the convex bank 3. In this embodiment, the angle between the axis of the wooden pile groyne and the tangent of the convex bank 3 is 30°.

[0025] Furthermore, the groyne diversion dam comprises multiple rows of wooden piles 21 extending along the axial direction. The rows of piles 21 are parallel to each other, and the piles 21 in each row are spaced apart. The lower ends of the piles 21 located in the river channel are fixed to the riverbed by foundation fixing components 8, while the lower ends of the piles 21 located on the convex bank 3 slope are directly buried in the slope soil. In this embodiment, the groyne diversion dam is a double-row wooden pile structure.

[0026] The foundation fixing component 8 can be a precast concrete anchor block, with a steel sleeve pre-embedded in the top of the precast concrete anchor block. After the lower end of the wooden pile 21 is inserted into the sleeve, it is fixed with a steel pin to form a stable anchoring structure. The precast concrete anchor blocks are placed on the riverbed surface, so that the lower end of the wooden pile 21 is fixed to the riverbed through the foundation fixing component 8.

[0027] The foundation fixing component 8 can also be a row of gabions. The row of gabions is laid on the riverbed surface, and the lower end of the wooden pile 21 is inserted and anchored in the row of gabions, so that the lower end of the wooden pile 21 is fixed to the riverbed by the foundation fixing component 8.

[0028] In some embodiments, in order to guide the direction of water flow and stabilize the terrain, such as Figure 3As shown, gabion anchors 7 are pre-placed in the area where the deep pool habitat unit 4 is expected to be formed. After the deep pool habitat unit 4 is stably formed under the action of water flow, the gabion anchors 7 are located at the bottom and / or slope of the deep pool habitat unit 4.

[0029] To further optimize the ecological function of the deep pool habitat unit 4, especially to provide shelter and ambush sites for bottom-dwelling, ambush-type fish such as snakehead and catfish, a second habitat substrate group 62 is set up on the gentle slope at the edge of the deep pool habitat unit 4. The second habitat substrate group 62 includes multiple piles of large stones. The size of the large stones is greater than 50 cm. After the deep pool habitat unit 4 is stabilized and formed under the action of water flow, these piles of large stones are located on the gentle slope at the edge of the deep pool habitat unit 4, and the gaps and cavities between them provide an ideal habitat environment for fish.

[0030] like Figure 4 As shown, when the first habitat substrate group 61 is laid on the surface of the shallow water habitat unit 5, it is configured in stages according to the surface flow velocity of the shallow water habitat unit 5 during the normal water period, so as to adapt to different hydraulic conditions and achieve targeted ecological functions. In the area with a flow velocity greater than or equal to 0.5 m / s (usually located on the upper part of the shallow water near the main flow), flat pebbles with a particle size of 30-50 cm are mainly laid. This particle size and shape can effectively resist water erosion. The flat pebbles with a particle size of 30-50 cm are arranged into multiple pebble bands parallel to the shoreline of the convex bank 3, with a spacing of about 1.5 meters between the pebble bands, providing the main spawning attachment substrate for fish. In the area with a flow velocity less than 0.5 m / s (usually located on the slow-flowing side near the shore), smaller pebbles with a particle size of 10-20 cm are mainly laid. The smaller pebbles with a particle size of 10-20 cm are aggregated into multiple pebble clusters, each pebble cluster with a diameter of 1 to 3 meters, providing shelter for juvenile fish and small shrimp and crabs. The arrangement of the second habitat substrate group 61 and the hierarchical configuration of the first habitat substrate group 61 enable the substrate to adapt to different hydraulic conditions and provide suitable habitat microenvironments for different organisms.

[0031] Furthermore, when laying the first habitat substrate group 61 to form the pebble belt and pebble clusters, a graded design is adopted: that is, based on pebbles with a particle size of 30-50 cm or 10-20 cm as the main framework, 10% to 20% by volume of small gravel with a particle size of 2 to 5 cm is mixed into the pores of the main framework to fill the pores between the large-diameter pebbles, thereby enhancing the stability of the overall structure and the complexity of the microhabitat. Example 2:

[0032] This embodiment uses a small-to-medium-sized river in a plain area of ​​central my country as an example to illustrate a method for constructing a multi-level biological habitat system in a meandering river channel at a small to medium scale. The selected river section is a typical meandering river, approximately 25 meters wide, with a longitudinal slope of about 1 / 1500. The riverbed is mainly sandy loam with a small amount of gravel. The tortuosity (ratio of the length of the river centerline to the straight length of the valley) of the selected river section is 2.1, showing the natural meandering characteristics of the river, which is usually associated with concave bank erosion and convex bank deposition. However, the current habitat is relatively monotonous, lacking diverse structures such as deep pools and shallows, which limits the enhancement of biodiversity.

[0033] A method for constructing a multi-level biological habitat system in a meandering river channel at a small to medium scale, comprising the following steps: Step 1: Site Identification and Functional Zoning Based on the results of hydrogeological surveys and topographic measurements, a diversion zone and a siltation zone are planned on the convex bank 3, and a target concave bank scour zone is planned on the concave bank 1. The diversion zone is located on the upstream side of the bend of the convex bank 3, and its function is to install permeable diversion units 2. The siltation zone is located on the bend and downstream side of the convex bank 3, and is used to create shallow beach habitat units 5. The target concave bank scour zone is located in the concave area of ​​the concave bank 1, and is used to create deep pool habitat units 4.

[0034] Step 2: Based on the diversion zone, deploy permeable diversion units 2 that extend into the river.

[0035] In this embodiment, a wooden pile groynes are used as the permeable diversion unit 2.

[0036] Design and construction: The wooden pile diversion groynes are designed as double-row wooden pile structures, with the angle between the axis and the tangent of the convex bank 3 being 30°.

[0037] The length of the wooden pile diversion groynes is one-third of the river width, approximately 8 meters, extending from the diversion area into the river channel.

[0038] Wooden stake 21 is made of hardwood round logs treated with anti-corrosion, with a stake diameter of 20 cm and a stake spacing of 3 times the stake diameter (i.e., 60 cm) to ensure its permeability.

[0039] Given the relatively loose riverbed, precast concrete anchor blocks are used as the foundation fixing components 8 for the wooden piles 21 extending into the river channel. The anchor block dimensions are 1.0 m × 0.8 m × 0.5 m (length × width × height), with a steel sleeve pre-embedded at the top. For the wooden piles 21 located on the convex bank 3 slope, the lower end of the wooden piles 21 is directly buried in the slope soil.

[0040] During construction, precast concrete anchor blocks were first placed on the riverbed surface at the designed positions and partially embedded in the riverbed. Then, the lower end of the wooden pile 21 was inserted into the pre-embedded steel sleeve of the precast concrete anchor block and fixed with steel pins, forming a stable "anchor block-wooden pile" anchoring system. Simultaneously, the construction of the wooden pile 21 located on the convex bank 3 slope was completed.

[0041] Wooden pile diversion groynes gently guide the surface water flow in the river channel to the target concave bank scour area. At the same time, the permeability of the wooden pile diversion groynes can create a low flow velocity zone on the back side of the dam, which can serve as a still water nurturing zone behind the dam.

[0042] Step 3: Shaping the deep pool habitat unit 4 and the shallow water habitat unit 5; This step relies on the hydraulic action generated by the wooden pile diversion groynes installed in step 2, the principle of which is as follows: Figure 3 As shown.

[0043] Shaping Deep Pool Habitat Unit 4: At the center of the target concave bank scour area, three gabion anchors weighing approximately 0.5 tons each were pre-placed as "seeds" for scour. After one hydrological year (including the high-water season), under the continuous action of the wooden pile diversion groynes, the scour of the concave bank 1 was intensified, and a deep pool habitat unit 4, approximately 10 meters long and with an average depth approximately 1.0 meter deeper than the original riverbed, gradually developed around the gabion anchors 7. This deep pool habitat unit 4 serves as a wintering refuge for fish, providing an important wintering shelter, feeding ground, and habitat for large fish.

[0044] Shaping of Shallow Beach Habitat Unit 5: On the backwater side of the wooden pile diversion groyne, the water flow velocity decreases significantly, and suspended sediment and some bed sand from upstream settle in the convex bank siltation zone. Through concurrent hydrological processes, this convex bank siltation zone naturally rises, forming a shallow habitat unit 5 with an average depth of approximately 0.3 meters and an area of ​​approximately 60 square meters. This shallow habitat unit 5 serves as a shallow spawning and foraging area for fish, providing crucial spawning, juvenile rearing, and foraging sites.

[0045] Step 4: Refined Configuration of Habitat Functions like Figure 4 As shown, after the deep pool habitat unit 4 and shallow beach habitat unit 5 were successfully established, the substrate was finely configured.

[0046] Configuration of the first habitat matrix group 61: Velocity Calculation, Measurement, and Zoning: Within the shallow water habitat unit 5, surface flow velocities during the normal water period were measured. Areas with flow velocities higher than 0.5 m / s (mainly located on the upper part of the shallow water near the main flow side) were classified as the high-velocity zone of the shallow water; areas with flow velocities lower than 0.5 m / s (mainly located on the nearshore slow-flow side) were classified as the low-velocity zone of the shallow water.

[0047] In the high-velocity areas of the shallows, flat pebbles with a diameter of 30-50 cm are mainly laid out to resist water erosion. The pebbles are arranged in 2 to 3 strips parallel to the shoreline of the convex bank, with a spacing of about 1.5 meters between the strips, serving as the main spawning substrate for fish. In the low-velocity areas of the shallows, smaller pebbles with a diameter of 10-20 cm are mainly laid out, forming clusters, each cluster with a diameter of about 2 meters, providing shelter for juvenile fish and small shrimp and crabs.

[0048] It should be noted that, during the configuration of the first habitat substrate group 61 and the second habitat substrate group 62, small-diameter gravels with a volume ratio of about 15% and a particle size of 2-5 cm were intentionally mixed in to fill the pores between the large pebbles and enhance the structural stability and complexity.

[0049] Secondary habitat substrate group configuration 62: At the edge of the gentle slope of the deep pool habitat unit 4, several piles of large stones with a diameter greater than 50 centimeters were placed to serve as shelter and ambush sites for fish (such as snakehead and catfish).

[0050] This invention actively guides and utilizes the natural hydraulic power of a meandering river channel through a permeable diversion unit 2, creating a deep pool habitat unit 4 and a shallow beach habitat unit 5, minimizing disturbance to the natural environment. Furthermore, by configuring a second habitat matrix group 62 and a first habitat matrix group 61 within the deep pool habitat unit 4 and the shallow beach habitat unit 5 respectively, a high-quality multi-level biological habitat system with multiple functions, stable structure, and self-sustaining capabilities is constructed.

[0051] It should be noted that the specific embodiments described in this invention are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains can make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A multi-level biological habitat system in a meandering river channel at a small to medium scale, wherein the river channel has opposing convex banks (3) and concave banks (1), characterized in that, The system includes: The permeable diversion unit (2) is installed on the convex bank (3) of the river channel and extends into the river to guide the upstream mainstream to the concave bank (1); it is also used to reduce the water flow velocity on the back side of the permeable diversion unit (2) to promote siltation. The deep pool habitat unit (4) is located downstream of the concave bank (1) opposite to the permeable diversion unit (2), and is naturally formed by the guided water flow scouring the concave bank (1) and the riverbed below it. The shallow water habitat unit (5) is located on the convex bank (3) on the back side of the permeable diversion unit (2) and is naturally formed by siltation. Among them, the deep pool habitat unit (4) is provided with a second habitat matrix group (62), and the surface of the shallow beach habitat unit (5) is provided with a first habitat matrix group (61).

2. The small-to-medium scale meandering river multi-level biological habitat system according to claim 1, characterized in that, The permeable diversion unit (2) is a wooden pile diversion groynes. The axis of the wooden pile diversion groynes extends from the convex bank (3) into the river channel and points downstream. The angle between the axis and the tangent of the shoreline of the convex bank (3) is 15° to 60°.

3. The small-to-medium scale meandering river multi-level biological habitat system according to claim 2, characterized in that, The wooden pile diversion groynes contain multiple rows of wooden piles (21) extending along the axial direction. The rows of wooden piles (21) are parallel to each other, and the wooden piles (21) in each row are spaced apart. The lower ends of the wooden piles (21) located in the river channel are fixed to the riverbed by foundation fixing components (8), and the lower ends of the wooden piles (21) located on the convex bank (3) slope are directly buried in the slope soil.

4. The small-to-medium scale meandering river multi-level biological habitat system according to claim 3, characterized in that, The foundation fixing component (8) is a precast concrete anchor block. A steel sleeve is pre-embedded on the top of the precast concrete anchor block. The lower end of the wooden pile (21) is anchored in the steel sleeve. The precast concrete anchor block is laid on the surface of the riverbed.

5. The small-to-medium scale meandering river multi-level biological habitat system according to claim 3, characterized in that, The basic fixing component (8) is a row of gabions, which are laid on the riverbed surface. The lower end of the wooden pile (21) is inserted and anchored in the row of gabions.

6. The small-to-medium scale meandering river multi-level biological habitat system according to claim 4, characterized in that, The deep pool habitat unit (4) is equipped with a gabion anchor (7), which is located at the bottom and / or slope of the deep pool habitat unit (4).

7. The small-to-medium scale meandering river multi-level biological habitat system according to claim 6, characterized in that, The second habitat matrix group (62) includes several large rock piles located on the gentle slope at the edge of the deep pool habitat unit (4), with the large rocks having a diameter greater than 50 cm.

8. The small-to-medium scale meandering river multi-level biological habitat system according to claim 7, characterized in that, The first habitat substrate group (61) includes flat pebbles with a diameter of 30-50 cm and smaller pebbles with a diameter of 10-20 cm. The flat pebbles with a diameter of 30-50 cm are arranged into multiple pebble bands parallel to the shoreline of the convex bank (3). The pebble bands are located in the shallow water habitat unit (5) in the area where the surface flow velocity is greater than or equal to 0.5 m / s during the normal water period. The smaller pebbles with a diameter of 10-20 cm are aggregated into multiple pebble clusters. The diameter of each pebble cluster is 1 to 3 meters. The pebble clusters are located in the shallow water habitat unit (5) in the area where the surface flow velocity is less than 0.5 m / s during the normal water period.

9. The small-to-medium scale meandering river multi-level biological habitat system according to claim 8, characterized in that, When laying the first habitat substrate group (61) to form the pebble belt and pebble cluster, on the basis of pebbles with a particle size of 30-50 cm or 10-20 cm as the main skeleton, 10% to 20% by volume of small gravel with a particle size of 2 to 5 cm is mixed into the pores of the main skeleton.

10. A method for constructing a small-to-medium scale meandering river multi-level biological habitat system, comprising the following steps: Step 1: Plan the diversion zone and the siltation zone on the convex bank (3), and plan the target concave bank scouring zone on the concave bank (1); Step 2: Place the precast concrete anchor block on the riverbed surface according to the design position and partially embed it into the riverbed. Anchor the lower end of the wooden pile (21) located in the riverbed into the pre-embedded steel sleeve of the precast concrete anchor block. Bury the lower end of the wooden pile (21) located on the convex bank (3) slope directly into the slope soil to form a permeable diversion unit (2) extending into the river based on the diversion area. Step 3: Place a gabion anchor (7) at the center of the target concave bank scour area. The target concave bank scour area forms a deep pool habitat unit (4) under the natural scour of the water flow. The convex bank siltation area forms a shallow beach habitat unit (5) after the accumulation of silt. Step 4: In the shallow water habitat unit (5), measure the surface flow velocity during the normal water period. Divide the area with a flow velocity higher than 0.5 m / s into the shallow water high flow velocity zone and the area with a flow velocity lower than 0.5 m / s into the shallow water low flow velocity zone. In the shallow water high flow velocity zone, lay out multiple pebble strips parallel to the shoreline of the convex bank (3). In the shallow water low flow velocity zone, lay out multiple pebble clusters. On the gentle slope at the edge of the deep pool habitat unit (4), lay out multiple large stone piles.

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