A method and system for riverbed habitat restoration using the "flushing fine and filling coarse" method for river sections where small hydropower projects have withdrawn
By obtaining hydrogeographic information of small hydropower exiting the river channel, determining key habitat areas and implementing pebble supplements and drifting stone group deployment, the problem of damage to river habitats after small hydropower exits is solved, and the natural landform and diverse habitats of rivers are restored.
Patent Information
- Application Number
- CN202411258962.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-10
- Publication Date
- 2025-08-12
- Estimated Expiration
- 2044-09-10
AI Technical Summary
After the small hydropower is withdrawn, the river habitat is damaged, and the river takes longer to recover or even cannot be restored during the recovery process. The existing technology fails to effectively manage silt and sand, resulting in river degradation.
By obtaining the hydrogeographic information of small hydropower exiting the river channel, key habitat areas are determined, and the location and thickness of the water flow sludge are used to implement pebble replenishment, drifting stone group layout, ecological Ding Dam and ecological water guide dam setting, forming a riverbed bottom habitat restoration plan, and simulation and adjustment are carried out through the hydrodynamic sediment transfer model to finally restore the natural landform of the river.
The natural landform state of the river in the damaged section has been restored, the problem of damage to river degraded habitats has been reduced, and habitats suitable for fish and aquatic organisms have been formed, and the diversity of river hydrology, landforms and substrates has been improved.
Smart Images
Figure CN119195050B_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of ecological restoration, and in particular to a method and system for restoring riverbed sediment habitats using the "flushing fine and filling coarse" method in river sections where small hydropower stations have withdrawn. Background Art
[0002] In recent years, with the active progress of small hydropower cleanup and rectification, a large number of small hydropower projects on mountain rivers have been phased out, and dams have been removed, restoring the vertical connectivity of rivers upstream and downstream. Although the small hydropower phaseout is intended to restore natural river connectivity and prevent the deterioration of the river's ecological environment, the failure to implement effective sediment management measures during the dam removal process has resulted in short-term damage to river habitats, making subsequent river recovery more time-consuming or even impossible. Summary of the Invention
[0003] The purpose of this application is to provide a "flushing and coarsening" type riverbed bottom habitat restoration method and system for river sections where small hydropower has withdrawn, which can reduce the problem of damaged river habitats caused by the withdrawal of small hydropower, restore damaged river sections caused by the withdrawal of small hydropower, and restore the natural landform of the river.
[0004] To achieve the above objectives, this application provides the following solutions:
[0005] Firstly, the present application provides a method for riverbed bottom habitat restoration in river sections where small hydropower projects have been withdrawn, using the "flushing fine soils and filling coarse soils" method, comprising:
[0006] Obtaining hydrological and geomorphological information on river channels where small hydropower withdrawal has been implemented; the hydrological and geomorphological information includes basic river channel information, riverbed topography maps within the river sections affected by the withdrawal of small hydropower, riverbed matrix particle size distribution maps within the river sections affected by the withdrawal of small hydropower, and sediment layer distribution maps within the river sections affected by the withdrawal of small hydropower;
[0007] Based on the basic information of the river channel, the hydrodynamic condition judgment method is used to determine the distribution of key habitat areas in the river section affected by the withdrawal of small hydropower, based on the hydrodynamic sediment transport model and the accessibility requirements of key aquatic habitats, and a key habitat restoration layout map is drawn;
[0008] Determine the substrate particle size of the key habitat area and the location and thickness of the sediment to be flushed by water flow based on the key habitat restoration layout map, the riverbed topography map, the riverbed substrate particle size distribution map, and the sediment layer distribution map;
[0009] Determine a riverbed habitat restoration plan based on the key habitat restoration layout, the substrate particle size of the key habitat area, and the location and thickness of the sediment erosion by water flow; the riverbed habitat restoration plan includes a pebble replenishment plan, a boulder group layout plan, an ecological spur dike installation plan, and an ecological water diversion weir installation plan;
[0010] Based on the riverbed sediment habitat restoration plan and the hydrodynamic sediment transport model, the restoration effect of the river channel where small hydropower has been withdrawn is simulated, and the riverbed sediment habitat restoration plan is adjusted according to the simulation results to obtain the optimal riverbed sediment habitat restoration plan.
[0011] Optionally, obtain hydrological and geomorphological information of the river channel where small hydropower has been withdrawn, including:
[0012] Obtain basic information on rivers where small hydropower withdrawal has been implemented;
[0013] Determine the location of the river section where the small hydropower station will be withdrawn in the river channel, and determine the impact range of the river section where the small hydropower station will be withdrawn based on the location of the river section where the small hydropower station will be withdrawn in the river channel;
[0014] Within the influence range of the river section affected by the withdrawal of small hydropower, riverbed topography mapping, riverbed matrix particle size analysis and silt layer thickness measurement are carried out, and riverbed topography maps, riverbed matrix particle size distribution maps and silt layer distribution maps of the river section affected by the withdrawal of small hydropower are drawn.
[0015] Optionally, determining the impact range of the river section where the small hydropower station is to be withdrawn, based on the location of the river section where the small hydropower station is to be withdrawn in the river channel, specifically includes:
[0016] Determine the scope of the reservoir area before the small hydropower station is dismantled based on the location of the river section to be withdrawn from the small hydropower station and the reservoir water level-reservoir capacity curve;
[0017] According to the location of the small hydropower exit section in the river channel, determine the longitudinal slope of the downstream river channel, the distribution of the stepped riverbed and the gentle slope section of the river channel;
[0018] Determine the impact range of downstream sediment release after the removal of small hydropower stations based on the longitudinal slope of the downstream river channel, the distribution of the stepped riverbed, and the gently sloping river channel;
[0019] The impact range of the river section where small hydropower is withdrawn is determined based on the reservoir area before the removal of the small hydropower and the impact range of downstream sediment release after the removal of the small hydropower.
[0020] Optionally, based on the key habitat restoration layout map, the riverbed topography map, the riverbed substrate particle size distribution map, and the sediment layer distribution map, determining the substrate particle size in the key habitat area and the location and thickness of the sediment to be flushed by water flow specifically includes:
[0021] According to the key habitat restoration layout map and the riverbed substrate particle size distribution map, the substrate particle size of the key habitat area is evaluated to obtain the substrate particle size situation of the key habitat area;
[0022] According to the key habitat restoration layout map, the riverbed topography map and the silt layer distribution map, the key habitat areas and the location and thickness of the silt to be flushed by water flow are determined.
[0023] Optionally, the key habitat areas include spawning grounds, feeding grounds, wintering grounds and cold-water fish lurking areas.
[0024] Optionally, the pebble replenishment scheme is to replenish pebbles in the area of the convex bank of the river channel where the particle size of the sediment layer is smaller than a set coarse particle size threshold;
[0025] The boulder group layout plan is to set up boulder groups in the wide and shallow parts of the straight river, the water intake of the hydropower station and the flood discharge channel, so as to use the water flow power to wash away the sediment with a particle size smaller than the set fine particle size threshold;
[0026] The ecological spur dike installation scheme is to install ecological spur dikes on the concave banks of the river, in the reservoir area and in the local flat river sections, so as to use the water flow dynamics to flush out the sediment with a particle size smaller than the set fine particle size threshold;
[0027] The ecological water diversion weir setting plan is to set up ecological water diversion weirs in straight river sections and streams with slopes less than a set slope threshold at the entrance of river bends, and use water flow dynamics to flush sediment with particle sizes less than a set fine particle size threshold, so that the fine-grained sediment in the riverbed is flushed to both sides of the downstream of the ecological water diversion weir.
[0028] Optionally, the weight of the pebbles supplemented by the pebble supplementation scheme is: W s =h c ×S c ×ρ d ×[(1-a) / 0.4-a]; where, W s is the weight of the pebble, h c is the thickness of the sediment layer in the spawning ground, S c is the area of the spawning ground, ρ d is the density of the sediment layer, a is the matrix content in the sediment layer soil sample that meets the particle size range of the spawning ground;
[0029] The particle size of the pebbles supplemented by the pebble supplementation scheme is larger than the set median particle size;
[0030] The roundness of the pebbles supplemented by the pebble supplementation scheme is greater than 0.6.
[0031] Optionally, the length and placement angle of the ecological spur dam set in the ecological spur dam setting plan are determined according to the bed-forming flow or the design flood flow, and sediment transport simulation is performed based on a hydrodynamic model.
[0032] Optionally, the shape of the ecological water diversion weir provided in the ecological water diversion weir setting scheme is a "V" shape or a "U" shape opening upstream.
[0033] Secondly, this application provides a riverbed bottom habitat restoration system for river sections where small hydropower projects have been withdrawn, which includes:
[0034] An information acquisition module is used to obtain hydrological and geomorphological information of the river channel where small hydropower withdrawal has been implemented; the hydrological and geomorphological information includes basic river channel information, riverbed topography within the river section affected by the withdrawal of small hydropower, riverbed matrix particle size distribution map within the river section affected by the withdrawal of small hydropower, and sedimentation layer distribution map within the river section affected by the withdrawal of small hydropower;
[0035] A key habitat determination module is used to determine the distribution of key habitat areas within the river section affected by the withdrawal of small hydropower, and to draw a key habitat restoration layout map based on the basic information of the river channel, the hydrodynamic condition judgment method, the hydrodynamic sediment transport model, and the accessibility requirements of key habitats for aquatic organisms;
[0036] A key habitat analysis module is used to determine the substrate particle size of the key habitat area and the location and thickness of the sediment to be flushed by water flow based on the key habitat restoration layout map, the riverbed topography map, the riverbed substrate particle size distribution map, and the sediment layer distribution map;
[0037] a scheme determination module for determining a riverbed substrate habitat restoration scheme based on the key habitat restoration layout diagram, the substrate particle size of the key habitat area, and the location and thickness of the sediment erosion by water flow; the riverbed substrate habitat restoration scheme includes a pebble replenishment scheme, a boulder group layout scheme, an ecological spur dike setting scheme, and an ecological water diversion weir setting scheme;
[0038] The scheme adjustment module is used to simulate the restoration effect of the river channel where small hydropower has been withdrawn based on the riverbed substrate habitat restoration scheme and the hydrodynamic sediment transport model, and adjust the riverbed substrate habitat restoration scheme according to the simulation results to obtain the optimal riverbed substrate habitat restoration scheme.
[0039] According to the specific embodiments provided in this application, this application discloses the following technical effects:
[0040] The present application provides a method and system for riverbed bottom habitat restoration in a river section where small hydropower has been withdrawn, using a "flushing and filling" method. By analyzing the hydrological and geomorphological information of the river channel where small hydropower has been withdrawn, the key habitat areas in the river section affected by the withdrawal of small hydropower are determined, and the matrix particle size in the key habitat areas and the location and thickness of the silt flushing and silting by water flow are determined. Based on the above analysis results, a riverbed bottom habitat restoration plan is determined. The riverbed bottom habitat restoration plan includes pebble supplementation, boulder group layout, ecological spur dike setting and ecological water diversion weir setting. The restoration effect is simulated based on a hydrodynamic sediment transport model, and the restoration plan is adjusted to form the four optimal plans, thereby repairing the riverbed bottom habitat, reducing the problem of damaged river habitat degradation caused by the withdrawal of small hydropower, and being able to restore the damaged river section degraded by the withdrawal of small hydropower, and restore the natural geomorphological state of the river. BRIEF DESCRIPTION OF THE DRAWINGS
[0041] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0042] Figure 1 A flow chart of a method for riverbed bottom habitat restoration using the "flushing fine soils and filling coarse soils" method for river sections where small hydropower projects have been withdrawn, provided in one embodiment of the present application;
[0043] Figure 2 This is a schematic diagram of the restoration of cross-sectional landform diversity after the "fine-digging and thickening" process in a meandering river section;
[0044] Figure 3 This is a cross-sectional diagram of the boulders laid out at the original power station’s water intake;
[0045] Figure 4 This is a plan view of the arrangement of boulders at the water intake of the original power station;
[0046] Figure 5 Schematic diagram of setting up boulder "thinning" in a wide and shallow river section;
[0047] Figure 6 This is a structural diagram of the U-shaped ecological water diversion weir;
[0048] Figure 7 A schematic diagram of the terraced landform formed by "flushing fine water and supplementing coarse water" in the straight river section;
[0049] Figure 8 A schematic diagram of the overall layout of a riverbed habitat restoration solution provided in one embodiment of the present application;
[0050] Figure 9This is a functional module diagram of a riverbed bottom habitat restoration system of the "flushing fine and filling coarse" type for a river section where small hydropower is withdrawn, according to one embodiment of the present application.
[0051] Description of reference numerals:
[0052] 1-Reservoir released sediment cover, 2-Deep pool, 3-Pebbles, 4-Shoal, 5-Boulder group, 6-Original hydropower station water inlet, 7-Scouring pit, 8-Bottom rocks, 9-Stones larger than the rest of the wave crests, 10-Width of the ecological water diversion weir, 11-Length of the ecological water diversion weir, 12-Ecological water diversion weir, 13-Original retaining dam, 14-Original overflow dam, 15-Ecological spur dike. DETAILED DESCRIPTION
[0053] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.
[0054] During the dam removal process, due to a lack of consideration for pre-treatment of sediment accumulation in the reservoir area and the rapid demolition, a large amount of sediment accumulated over many years within the reservoir was rapidly discharged downstream. The riverbed for several kilometers, sometimes even dozens of kilometers, was covered with fine-grained sediment, flattening the river's cross-section. This buried natural geomorphic elements such as fish spawning grounds, eliminated the pores between the substrates in feeding grounds, degraded the habitats needed by benthic organisms and other fish prey, and covered the large pebbles necessary for fish spawning and the attachment of sticky eggs. Furthermore, the filling of deep pools and shoals in natural rivers caused significant temperature fluctuations in the wide, shallow rivers due to the influence of sunlight, eliminating the wintering grounds and cold-water fish lurking areas necessary for bottom-dwelling fish.
[0055] For river sections where habitats are damaged due to the withdrawal of small hydropower, this application provides a "flushing fine and filling coarse" type riverbed bottom habitat restoration method, which aims to restore the riverbed bottom habitat of the original reservoir area and the river section downstream of the dam by using natural hydrological forces such as floods, through the replenishment of pebbles, the layout of boulder groups, ecological diversion diversion facilities such as ecological spur dikes and ecological water diversion weirs, restore the natural landform of the river, form a natural river habitat system with spawning grounds, refuges, wintering grounds, etc., and restore the damaged river sections that have been degraded due to the withdrawal of small hydropower.
[0056] "Flushing" refers to using water flow to flush out unreasonably deposited fine sediment, moving it downstream or to areas where it can accumulate. Fine sediment refers to sand, silt, and clay particles with a particle size of less than 2 mm.
[0057] "Coarse filling" refers to adding pebbles that are too fine and lack the sticky material for fish eggs to attach to and juvenile fish to take shelter. The particle size range of the pebbles is 16mm to 80mm.
[0058] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.
[0059] In an exemplary embodiment, Figure 1 As shown, a method for riverbed bottom habitat restoration of a river section where small hydropower is withdrawn by "flushing fine soils and filling coarse soils" is provided, comprising the following steps 101 to 105.
[0060] Step 101: Obtain hydrological and geomorphological information of the river channel where small hydropower has been withdrawn.
[0061] The hydrological and geomorphological information includes basic river channel information, riverbed topography maps within river sections affected by the withdrawal of small hydropower stations, riverbed matrix particle size distribution maps within river sections affected by the withdrawal of small hydropower stations, and silt layer distribution maps within river sections affected by the withdrawal of small hydropower stations.
[0062] In a specific example, a survey of hydrological and geomorphological conditions is conducted on a river channel where small hydropower has been withdrawn, and step 101 includes the following steps 201 to 203.
[0063] Step 201: Obtain basic information about the river channel where small hydropower has been withdrawn. The basic information includes the river channel length, river channel longitudinal slope, drainage area, planar shape, distribution of tributaries, underground rivers, bedrock distribution, etc.
[0064] Step 202: determine the location of the river section where the small hydropower station will be withdrawn in the river channel, and determine the impact range of the river section where the small hydropower station will be withdrawn based on the location of the river section where the small hydropower station will be withdrawn in the river channel.
[0065] Specifically, first, based on the position of the river section where the small hydropower station will be withdrawn in the river channel and the water level-capacity curve of the reservoir area, the scope of the reservoir area before the small hydropower station is dismantled is determined. Then, based on the position of the river section where the small hydropower station will be withdrawn in the river channel, the longitudinal slope of the downstream river channel, the distribution of the stepped riverbed and the gently sloping river channel are determined. Based on the longitudinal slope of the downstream river channel, the distribution of the stepped riverbed and the gently sloping river channel, the scope of influence of the downstream sediment release after the small hydropower station is dismantled is determined. Then, based on the scope of the reservoir area before the small hydropower station is dismantled and the scope of influence of the downstream sediment release after the small hydropower station is dismantled, the scope of influence of the river section where the small hydropower station is dismantled is determined. Among them, the scope of influence of the river section where the small hydropower station is dismantled includes the scope of the reservoir area before the small hydropower station is dismantled and the scope of influence of the downstream sediment release after the small hydropower station is dismantled.
[0066] Step 203: within the influence range of the river section where the small hydropower is withdrawn, riverbed topography mapping, riverbed matrix particle size analysis, and sedimentation layer thickness measurement are performed, and a riverbed topography map, a riverbed matrix particle size distribution map, and a sedimentation layer distribution map of the river section affected by the withdrawal of small hydropower are drawn.
[0067] Among them, the thickness of the silt layer is measured by on-site drilling and excavation, the thickness of the silt layer in the affected river section is determined, and a silt layer distribution map is drawn.
[0068] Step 102: Based on the basic river channel information, a hydrodynamic condition assessment method is used to determine the distribution of key habitat areas within the river section affected by the small hydropower withdrawal, using a hydrodynamic sediment transport model and the accessibility requirements for key aquatic habitats. A key habitat restoration layout map is then drawn. The accessibility requirements for key aquatic habitats include ensuring that the distance is not too far, that the connecting path is unobstructed, and that the water depth is sufficient to prevent grounding.
[0069] Specifically, based on basic river channel information and using a hydrodynamic assessment method, a hydrodynamic sediment transport model is established to determine the riverbed shields number (shear strength) and the matrix Reynolds number or Froude number distribution. This allows the identification of the potential topography that will emerge upstream and downstream after erosion. Based on these hydrodynamic conditions, the distribution of key habitats within the affected river sections, such as spawning grounds, feeding grounds, wintering grounds, and cold-water fish ambush areas, is determined, and a key habitat restoration layout map is developed.
[0070] Step 103 , based on the key habitat restoration layout map, the riverbed topography map, the riverbed substrate particle size distribution map, and the sediment layer distribution map, determine the substrate particle size of the key habitat area and the location and thickness of the sediment to be flushed by water flow.
[0071] In a specific example, the substrate particle size of the key habitat area is evaluated based on the key habitat restoration layout map and the riverbed substrate particle size distribution map to obtain the substrate particle size situation of the key habitat area.
[0072] Specifically, the required particle size range and degree of compliance are determined by assessing substrate particle size in key habitats. For example, the appropriate pebble size range for spawning a specific protected fish species is 16mm to 80mm. The actual particle size range of sediment covered by the sediment layer is then determined to determine the degree of compliance and the size of the pebble still lacking.
[0073] Based on the key habitat restoration layout map, the riverbed topography map, and the silt layer distribution map, determine the location and thickness of silt removal in key habitat areas. For example, if a cold-water fish lurking area requires a water depth exceeding 1.5 meters to maintain a stable bottom water temperature in summer, the thickness of the silt layer to be removed will be determined based on the water depth conditions in that area.
[0074] Step 104 : Determine a riverbed habitat restoration plan based on the key habitat restoration layout diagram, the substrate particle size of the key habitat area, and the location and thickness of the sediment scouring by water flow.
[0075] In one embodiment, the critical habitat areas include spawning grounds, feeding grounds, wintering grounds, and cold-water fish resting areas.
[0076] The riverbed habitat restoration plan includes a pebble replenishment plan, a boulder group layout plan, an ecological spur dike installation plan, and an ecological water diversion weir installation plan. This application proposes modular facilities for the reservoir area and the downstream sediment release area after the removal of the small hydropower station. Each modular facility is described in detail below.
[0077] (1) Pebble supplementation program
[0078] The pebble replenishment scheme is to add pebbles to the areas where the particle size of the sediment layer in the convex bank of the river channel is smaller than the set coarse particle size threshold.
[0079] Specifically, the pebble replenishment plan refers to areas where, due to the fine particle size of the existing sediment layer in spawning and feeding grounds, appropriate coarse-grained pebbles are artificially added from outside the river channel to replenish the existing sediment layer. The pebble replenishment plan requires a design of the required weight, particle size range, and shape.
[0080] The weight of the added pebbles is: W s =h c ×S c ×ρ d ×[(1-a) / 0.4-a]; where, W s is the weight of the pebble; h c is the thickness of the sediment layer in the spawning ground, m; S c is the area of the spawning ground, m 2 ρ d is the density of the sediment layer, kg / m 3 ; a is the matrix content in the alluvial soil sample that meets the particle size range of the spawning ground, %.
[0081] The particle size of the supplementary pebbles should be larger than the set median particle size. Specifically, the supplementary pebbles should be screened to control the particle size range. The median particle size is determined according to the anti-scour particle size formula for maintaining stability of the foot guard stones under the design peak flow conditions of the river channel (i.e., the content of pebbles larger than this particle size should not be less than 50%). The anti-scour particle size formula is detailed in Appendix D.3.4 of the "Code for Design of Embankment Engineering" (GB50286). The supplementary particle size (upper and lower limits) should be the particle size required for spawning of the target fish species.
[0082] The roundness of the added pebbles must be greater than the set roundness threshold. Specifically, the added pebbles cannot be replaced by sharp stones. The roundness threshold is 0.6. The roundness calculation formula for pebbles is: Where Ψp is the roundness of the pebble, S is the length of the minor axis of the pebble, L is the length of the major axis of the pebble, and I is the length of the median axis of the pebble.
[0083] (2) Ecological spur dam setting plan
[0084] The ecological spur dike setting plan is to set up ecological spur dikes on the concave banks of the river, reservoir areas and local flat river sections, and use the power of water flow to flush out sediment with particle size smaller than the set fine particle size threshold.
[0085] Ecological spur dikes are mainly used to repair flat river sections and sort the riverbed matrix to form diverse landforms with scour holes at the dam head and siltation zones behind the dam. The matrix in the scour holes is coarsened, and fine-grained sediment is concentrated behind the dam by the rolling action of water flow.
[0086] When designing an ecological spur dike, key concerns are the depth and diameter of the scour pit, the length of the siltation zone, and the thickness of the sediment. The depth and particle size of the scour pit should meet the spawning needs of torrent-type sticky-eating fish. If the particle size is insufficient, large pebbles can be added. Because fish need to forage in nearby feeding grounds after spawning, the sedimentation zone downstream of the scour pit can be constructed as a feeding ground and habitat for macroinvertebrates.
[0087] In a specific example, the length and placement angle of the ecological spur dike are determined according to the bed-forming flow or the design flood flow, and sediment transport simulation is performed based on a hydrodynamic model.
[0088] like Figure 2 As shown, this application adjusts the cross-section of a meandering river channel covered by fine-grained sediment, creating a cross-sectional configuration with deep pools and shallows. The sediment cover 1 is released from the reservoir, and ecological spur dikes are installed on the concave bank of the river channel to "finely scour" the water, forming deep pools 2. These deep pools 2 can serve as wintering grounds and summer low-water-temperature incubation areas. Pebbles are added to the convex bank to "coarsen" the water, forming shallows 4. These shallows 4 can serve as feeding and spawning grounds.
[0089] (3) Boulder group layout plan
[0090] The plan for arranging the boulder groups is to set up boulder groups in the wide and shallow parts of the straight river channel, the water inlet of the hydropower station and the flood discharge channel, and use the power of water flow to wash away the sediment with a particle size smaller than the set fine particle size threshold.
[0091] Specifically, if Figures 3 to 5As shown, the boulder clusters 5 are located near the original hydropower station's water intake 6, the flood discharge channel, and river sections with wide, straight channels and gentle longitudinal slopes (0.5% to 1%), where the riverbed consists of a large amount of fine-grained sediment. The size of each boulder should meet flood control stability requirements for at least 50 or 100 years and should not be washed away under the design flood standard flow rate.
[0092] This application releases the sediment cover 1 in the reservoir area, sets up a group of boulders 5 in the wide and shallow part of the straight river channel, "scours and refines" the area around the boulders, sorts the particles and forms scouring pits 7. The formed scouring and silting landform becomes a good feeding ground.
[0093] This application further sets up boulder groups and ecological dikes in the reservoir area and some flat river sections where the deep channel line has deviated due to siltation and the original water intake and drainage structures, so as to form a deep channel line close to the center of the river channel in a "fine-fining" manner, and wash the fine particle cover layer to the shore side, covering the original deep channel line to form a stable bank slope. The riverbed of the newly formed deep channel line of the river is "coarsened", which is conducive to the migration channel of fish that have requirements for water depth. The river bank is refined to become a habitat for large invertebrates and a feeding ground for fish.
[0094] (4) Ecological water diversion weir setting plan
[0095] The plan for setting up ecological water diversion weirs is to set up ecological water diversion weirs in straight river sections and streams at the entrances of river bends where the slope is less than the set slope threshold, and use the power of water flow to flush sediment with a particle size less than the set fine particle size threshold, so that the fine-grained sediment in the riverbed is flushed to both sides of the downstream of the ecological water diversion weir.
[0096] In a specific example, the slope threshold is set at 3%. Ecological water diversion weirs can be used to redirect the deep-sea line of the river, allowing water to flow through shallow river sections to restore fish migration channels and flush fine-grained sediment in the center of the river to the sides of the river. Figure 6 As shown, the ecological water diversion weir is shaped like a "V" or "U" that opens upstream. The weir can be constructed of wood, stone, or other materials, but the foundation should extend beyond the depth of the scour pit to prevent instability. The bottom of the weir has a layer of rock 8. Depending on the specific situation, a stone 9 larger than the other crests is placed in the center of the weir. The width 10 of the weir is variable, and the length 11 of the weir ranges from 1 / 2 to 3 / 4 of the channel width.
[0097] like Figure 7 As shown, in this application, for river sections where the release of fine-grained sediment covering layer has led to the homogenization of the longitudinal slope of the river section and the disappearance of the terraced landform, an ecological water diversion weir 12 is set up to concentrate water flow to "finely scour" (i.e., to control water flow and attack sand) locally to form scouring pits, so that the fine-grained sediment in the riverbed is flushed to both sides of the downstream of the water diversion weir.
[0098] The above schemes are reasonably configured according to the actual river topography and habitat restoration needs, and ultimately achieve systematic restoration of the habitat in the river section affected by the withdrawal of small hydropower. The overall layout is as follows: Figure 8 As shown, Figure 8 Among them, 13 represents the original water retaining dam, 14 represents the original overflow dam, and 15 represents the ecological spur dam.
[0099] Step 105 simulates the restoration effect of the riverbed habitat after the small hydropower project has been withdrawn based on the riverbed habitat restoration plan and the hydrodynamic sediment transport model. The riverbed habitat restoration plan is adjusted based on the simulation results to obtain an optimal riverbed habitat restoration plan. The optimal riverbed habitat restoration plan is used to restore the riverbed habitat of the riverbed habitat after the small hydropower project has been withdrawn.
[0100] In a specific example, a hydrodynamic sediment transport model is used to predict the restoration effects of various schemes for the entire river section, forming a riverbed substrate particle size distribution map. This map is compared with the hydrodynamic conditions in step 102 and the evaluation results in step 103 to determine the stability of the riverbed substrate after scouring and silting, determine the specific predicted effects after the implementation of the scheme, and fine-tune the relevant parameters of the scheme to ultimately form the optimal riverbed substrate habitat restoration scheme.
[0101] This application can shape suitable hydrodynamic conditions, set up "targeted scouring and silting" for the original reservoir area and the river section downstream of the dam after the removal of small hydropower, carry out natural particle sorting of the riverbed bottom sediment, change the distribution of the original riverbed matrix, and form a natural river habitat system with spawning grounds, wintering grounds, and feeding grounds, reduce the problem of river degradation habitat damage caused by the withdrawal of small hydropower, quickly repair the river habitat affected by the withdrawal of small hydropower, restore the natural landform of the river, increase the diversity of river hydrology, landform, and matrix conditions, and create habitats required by various fish including spawning grounds, feeding grounds, foraging grounds, refuges, low-temperature lurking areas, etc., to form systematic landform conditions that are conducive to the life history of fish. Moreover, this application not only takes into account the survival needs of fish, but also strengthens the habitat conditions suitable for the survival of aquatic organisms such as large benthic invertebrates and aquatic plants, and meets the habitat requirements of species diversity.
[0102] Based on the same inventive concept, the embodiments of the present application also provide a system for repairing riverbed substrates in river sections where small hydropower stations have withdrawn, which is used to implement the aforementioned method for repairing riverbed substrates in river sections where small hydropower stations have withdrawn. The solution provided by this system is similar to the solution described in the aforementioned method. Therefore, the specific limitations of one or more embodiments of the system for repairing riverbed substrates in river sections where small hydropower stations have withdrawn, as provided below, can be found in the aforementioned method for repairing riverbed substrates in river sections where small hydropower stations have withdrawn, and will not be repeated here.
[0103] In an exemplary embodiment, Figure 9 As shown, a riverbed bottom habitat restoration system of the "flushing fine soil and filling coarse soil" type for river sections where small hydropower stations have withdrawn is provided, including: an information acquisition module 901, a key habitat determination module 902, a key habitat analysis module 903, a scheme determination module 904 and a scheme adjustment module 905.
[0104] The information acquisition module 901 is used to obtain hydrological and geomorphological information of the river channel where small hydropower has been phased out. The hydrological and geomorphological information includes basic river channel information, riverbed topography within the river section affected by the small hydropower phase-out, riverbed matrix particle size distribution within the river section affected by the small hydropower phase-out, and sediment layer distribution within the river section affected by the small hydropower phase-out.
[0105] The key habitat determination module 902 is used to determine the distribution of key habitat areas within the river section affected by the withdrawal of small hydropower, and draw a key habitat restoration layout map based on the basic information of the river channel, the hydrodynamic condition judgment method, the hydrodynamic sediment transport model and the accessibility requirements of key habitats for aquatic organisms.
[0106] The key habitat analysis module 903 is used to determine the substrate particle size of the key habitat area and the location and thickness of the sedimentation to be flushed by water flow based on the key habitat restoration layout map, the riverbed topography map, the riverbed substrate particle size distribution map and the sedimentation layer distribution map.
[0107] The scheme determination module 904 is used to determine the riverbed substrate habitat restoration scheme based on the key habitat restoration layout map, the substrate particle size of the key habitat area, and the location and thickness of the water flow scouring and silting. The riverbed substrate habitat restoration scheme includes a pebble supplementation scheme, a boulder group layout scheme, an ecological spur dike setting scheme, and an ecological water diversion weir setting scheme.
[0108] The scheme adjustment module 905 is used to simulate the restoration effect of the river channel where small hydropower has been withdrawn based on the riverbed substrate habitat restoration scheme and the hydrodynamic sediment transport model, and adjust the riverbed substrate habitat restoration scheme according to the simulation results to obtain the optimal riverbed substrate habitat restoration scheme.
[0109] In an exemplary embodiment, a computer device is provided, which may be a server or a terminal. The computer device includes a processor, memory, an input / output (I / O) interface, and a communication interface. The processor, memory, and I / O interface are connected via a system bus, and the communication interface is connected to the system bus via the I / O interface. The processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and computer program in the non-volatile storage medium. The database of the computer device is configured to store hydrological and geomorphological information of river channels where small hydropower withdrawal has been implemented. The I / O interface of the computer device is configured to exchange information between the processor and external devices. The communication interface of the computer device is configured to communicate with external terminals via a network connection. When executed by the processor, the computer program implements a "fine-water flushing and coarse-water filling" method for riverbed sediment habitat restoration in river sections where small hydropower withdrawal has been implemented.
[0110] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.
[0111] In an exemplary embodiment, a computer program product is provided, including a computer program. When the computer program is executed by a processor, the steps in the above method embodiments are implemented.
[0112] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.
[0113] Those skilled in the art will understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, database or other media used in the embodiments provided in this application may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory may include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).
[0114] The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processors involved in the various embodiments provided herein may include, but are not limited to, general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic units, data processing logic units based on quantum computing, and the like.
[0115] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0116] This document uses specific examples to illustrate the principles and implementation methods of this application. The description of the above examples is only intended to help understand the method and core concept of this application. At the same time, for those skilled in the art, based on the concept of this application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.
Claims
1. A method for riverbed habitat restoration in a river section where small hydropower projects have been withdrawn, characterized in that: The "flushing fine and filling coarse" type riverbed habitat restoration method for river sections where small hydropower projects are withdrawn includes: Obtaining hydrological and geomorphological information on river channels where small hydropower withdrawal has been implemented; the hydrological and geomorphological information includes basic river channel information, riverbed topography maps within the river sections affected by the withdrawal of small hydropower, riverbed matrix particle size distribution maps within the river sections affected by the withdrawal of small hydropower, and sediment layer distribution maps within the river sections affected by the withdrawal of small hydropower; Based on the basic information of the river channel, a hydrodynamic condition judgment method is used to determine the distribution of key habitat areas in the river section affected by the withdrawal of small hydropower, based on the hydrodynamic sediment transport model and the accessibility requirements of key aquatic habitats. A key habitat restoration layout map is drawn; the key habitat areas include spawning grounds, feeding grounds, wintering grounds and cold-water fish lurking areas; Determine the substrate particle size of the key habitat area and the location and thickness of the sediment to be flushed by water flow based on the key habitat restoration layout map, the riverbed topography map, the riverbed substrate particle size distribution map, and the sediment layer distribution map; Determine a riverbed substrate habitat restoration plan based on the key habitat restoration layout, the substrate particle size of the key habitat area, and the location and thickness of the sediment eroded by water flow. The riverbed substrate habitat restoration plan includes a pebble replenishment plan, a boulder group layout plan, an ecological spur dike installation plan, and an ecological water diversion weir installation plan. The ecological water diversion weir installation plan includes a V-shaped or U-shaped weir opening upstream. Based on the riverbed substrate habitat restoration scheme and the hydrodynamic sediment transport model, the restoration effect of the river channel where small hydropower has been withdrawn is simulated, and the riverbed substrate habitat restoration scheme is adjusted according to the simulation results to obtain the optimal riverbed substrate habitat restoration scheme; specifically, the hydrodynamic sediment transport model is used to predict the restoration effect of each scheme in the entire river section, and a riverbed substrate particle size distribution map is formed. The map is compared with the hydrodynamic conditions and evaluation results to determine the stability of the riverbed substrate after scouring and silting, determine the specific predicted effect after the implementation of the scheme, and fine-tune the relevant parameters of the scheme to ultimately form the optimal riverbed substrate habitat restoration scheme.
2. The method for riverbed habitat restoration of a small hydropower station exiting a river section by "flushing fine soil and filling coarse soil" according to claim 1 is characterized in that: Obtain hydrological and geomorphological information on river channels where small hydropower projects have been phased out, including: Obtain basic information on rivers where small hydropower withdrawal has been implemented; Determine the location of the river section where the small hydropower station will be withdrawn in the river channel, and determine the impact range of the river section where the small hydropower station will be withdrawn based on the location of the river section where the small hydropower station will be withdrawn in the river channel; Within the influence range of the river section affected by the withdrawal of small hydropower, riverbed topography mapping, riverbed matrix particle size analysis and silt layer thickness measurement are carried out, and riverbed topography maps, riverbed matrix particle size distribution maps and silt layer distribution maps of the river section affected by the withdrawal of small hydropower are drawn.
3. The method for riverbed habitat restoration of a section of a river where small hydropower projects are withdrawn from the project according to claim 2 is characterized in that: Determine the impact range of the river section where the small hydropower project is to be withdrawn based on its location in the river channel, specifically including: Determine the scope of the reservoir area before the small hydropower station is dismantled based on the location of the river section to be withdrawn from the small hydropower station and the reservoir water level-reservoir capacity curve; According to the location of the small hydropower exit section in the river channel, determine the longitudinal slope of the downstream river channel, the distribution of the stepped riverbed and the gentle slope section of the river channel; Determine the impact range of downstream sediment release after the removal of small hydropower stations based on the longitudinal slope of the downstream river channel, the distribution of the stepped riverbed, and the gently sloping river channel; The impact range of the river section where small hydropower is withdrawn is determined based on the reservoir area before the removal of the small hydropower and the impact range of downstream sediment release after the removal of the small hydropower.
4. The method for riverbed habitat restoration of a small hydropower station exiting a river section by "flushing fine soil and filling coarse soil" according to claim 1 is characterized in that: Based on the key habitat restoration layout map, the riverbed topography map, the riverbed substrate particle size distribution map, and the sediment layer distribution map, determine the substrate particle size in the key habitat area and the location and thickness of the sediment to be flushed by water flow, specifically including: According to the key habitat restoration layout map and the riverbed substrate particle size distribution map, the substrate particle size of the key habitat area is evaluated to obtain the substrate particle size situation of the key habitat area; According to the key habitat restoration layout map, the riverbed topography map and the silt layer distribution map, the location and thickness of the siltation in the key habitat area using water flow are determined.
5. The method for riverbed habitat restoration of a section of a river where small hydropower projects are withdrawn from the project according to claim 1 is characterized in that: The pebble replenishment scheme is to replenish pebbles in the area where the particle size of the sediment layer in the convex bank of the river channel is smaller than the set coarse particle size threshold; The boulder group layout plan is to set up boulder groups in the wide and shallow parts of the straight river, the water intake and flood discharge channel of the hydropower station, and use the power of water flow to flush out the sediment with a particle size smaller than the set fine particle size threshold; The ecological spur dike installation scheme is to install ecological spur dikes on the concave banks of the river, in the reservoir area and in the local flat river sections, so as to use the water flow dynamics to flush out the sediment with a particle size smaller than the set fine particle size threshold; The ecological water diversion weir setting plan is to set up ecological water diversion weirs in straight river sections and streams with slopes less than a set slope threshold at the entrance of river bends, and use water flow dynamics to flush sediment with particle sizes less than a set fine particle size threshold, so that the fine-grained sediment in the riverbed is flushed to both sides of the downstream of the ecological water diversion weir.
6. The method for riverbed habitat restoration of a section of a river where small hydropower projects are withdrawn from the project according to claim 5 is characterized in that: The weight of the pebbles supplemented by the pebble supplementation scheme is: W s =h c ×S c ×ρ d ×[(1-a) / 0.4-a]; where, W s is the weight of the pebble, h c is the thickness of the sediment layer in the spawning ground, S c is the area of the spawning ground, ρ d is the density of the sediment layer, a is the matrix content in the sediment layer soil sample that meets the particle size range of the spawning ground; The particle size of the pebbles supplemented by the pebble supplementation scheme is larger than the set median particle size; The roundness of the pebbles supplemented by the pebble supplementation scheme is greater than 0.
6.
7. The method for riverbed habitat restoration of a section of a river where small hydropower stations are withdrawn from the project according to claim 5 is characterized in that: The length and placement angle of the ecological spur dam set in the ecological spur dam setting scheme are determined according to the bed-forming flow or the design flood flow and the sediment transport simulation based on the hydrodynamic model.
8. A riverbed subgrade habitat restoration system for a river section where small hydropower stations have withdrawn from the project, which is applied to the riverbed subgrade habitat restoration method for a river section where small hydropower stations have withdrawn from the project, characterized in that: The "flushing fine and filling coarse" type riverbed habitat restoration system for river sections where small hydropower projects are withdrawn includes: An information acquisition module is used to obtain hydrological and geomorphological information of the river channel where small hydropower withdrawal has been implemented; the hydrological and geomorphological information includes basic river channel information, riverbed topography within the river section affected by the withdrawal of small hydropower, riverbed matrix particle size distribution map within the river section affected by the withdrawal of small hydropower, and sedimentation layer distribution map within the river section affected by the withdrawal of small hydropower; A key habitat determination module is used to determine the distribution of key habitat areas within the river section affected by the withdrawal of small hydropower projects based on the basic information of the river channel, using a hydrodynamic condition judgment method, a hydrodynamic sediment transport model, and the accessibility requirements of key habitats for aquatic organisms, and to draw a key habitat restoration layout map, including the layout of spawning grounds, feeding grounds, wintering grounds, and cold-water fish ambush areas; A key habitat analysis module is used to determine the substrate particle size of the key habitat area and the location and thickness of the sediment to be flushed by water flow based on the key habitat restoration layout map, the riverbed topography map, the riverbed substrate particle size distribution map, and the sediment layer distribution map; a scheme determination module for determining a riverbed substrate habitat restoration scheme based on the key habitat restoration layout diagram, the substrate particle size of the key habitat area, and the location and thickness of the sediment erosion by water flow; the riverbed substrate habitat restoration scheme includes a pebble replenishment scheme, a boulder group layout scheme, an ecological spur dike setting scheme, and an ecological water diversion weir setting scheme; The scheme adjustment module is used to simulate the restoration effect of the river channel where small hydropower has been withdrawn based on the riverbed substrate habitat restoration scheme and the hydrodynamic sediment transport model, and adjust the riverbed substrate habitat restoration scheme according to the simulation results to obtain the optimal riverbed substrate habitat restoration scheme.