A double-layer overpass fishway structure

Abstract

The present invention discloses a double-layer overpass fishway structure, belonging to the field of fishway design in water conservancy projects. The double-layer overpass design enables an upper overflow and a lower submerged flow. The water flow structure within the pool chamber is diverse and can adapt to different water depths, creating favorable hydraulic conditions for fish with different preferences. The double-layer overpass fishway comprises: a trumpet-shaped inlet section, a hump-shaped weir transition section, a double-layer overpass pool section (including a lower disc-shaped channel section and an upper overflow section), and a resting pool section. The hump weir section divides the pool chamber into an upper overflow area and a lower submerged outflow area. The formation of the upper overflow area draws jumping fish into the upper overflow weir section, while the lower submerged flow area is used to attract bottom-dwelling fish and allow them to smoothly swim upstream through the disc-shaped channel section. The arrangement of the resting pool section creates a low-flow zone to allow fish to recover their strength, thereby allowing them to successfully complete their upstream migration and ensure the stability of the river ecosystem.

Description

Technical Field

[0001] The invention belongs to the field of fishway design in water conservancy projects, and in particular relates to a double-layer overpass fishway structure. Background Art

[0002] Dams, weirs, and other water-retaining structures block the natural migration pathways of fish. Constructing fish passages to allow fish to overcome the water drop and pass through the dam is one of the measures to protect and develop fish resources in rivers. Among these, fishways are the longest-used and most widely used fish passage facilities. The purpose of constructing fishways is to help fish pass through obstacles in the river, restore their migration behavior, offset the negative impacts of water conservancy projects on the river's ecological environment, and maintain the river's biodiversity. Fishways can be categorized by their structural type into natural-looking, baffle, and trough types. The specifics are as follows:

[0003] Natural fishway. It is a bypass waterway with natural characteristics. It is a migratory channel built around the project using stones and gravel from natural river channels to imitate natural rivers. The general slope is 1% to 5%.

[0004] Trough fishways can be divided into simple trough and Daniel type. The simple trough is a trough connecting upstream and downstream, suitable for fish with strong swimming ability, and is rarely used in engineering projects. The Daniel type fishway has closely spaced baffles and sills on the inner wall and bottom of the trough to dissipate energy, and is suitable for water conservancy projects with smaller water heads.

[0005] Baffle fishways. They are divided into overflow weir type, submerged orifice type, vertical slit type, and combination type. Among them, the overflow weir fishway refers to the migration of fish over the top of the weir, which is particularly suitable for fish that live on the surface of the river and have the habit of jumping; the vertical slit fishway has multiple levels of pools built inside the water tank, and baffles and guide plates are arranged on the side walls and bottom plates of the water tank, forming vertical slits between the baffles and guide plates of each level of pool chamber; the fish holes of the submerged orifice fishway are completely submerged in water, which is more suitable for fish that like to swim in the middle or bottom layers of the water; the combination fishway is a combination of the above three types of fishways, which combines the advantages of the hydraulic characteristics of various fishways and has a more complex structure.

[0006] Some current research is combining several types of fishways to create new, modular fishways. For example, the Jinggangshan Navigation and Hydropower Project utilizes a combination of vertical slot and biomimicry fishways. Research is underway on combining these two types of fishways to ensure smooth fish passage. However, most of these fishways fail to meet the requirements for successful upstream migration for different fish species. The purpose of constructing a fishway is to aid fish migration. In addition to considering the advantages of combining different types of fishways, it's also important to understand the fish's swimming ability and whether the hydraulic characteristics within the fishway, such as flow patterns and flow rates, can be optimized for fish passage. Summary of the Invention

[0007] The purpose of the present invention is to design a double-layer overpass fishway structure including an upper overflow weir type and a lower trough type based on a comprehensive comparison of the advantages of different types of fishways and full consideration of the habits and swimming abilities of fish, so as to solve the existing problem that the existing fishways have a single type of fish passage and a single water flow structure, which cannot meet the needs of some species of fish due to their own habits and requirements for the water flow environment, resulting in fewer fish passing through the fishways and a reduction in the diversity of river ecological species.

[0008] To achieve the above-mentioned object, the present invention provides the following technical solutions: a double-layer overpass fishway structure, comprising a trumpet-shaped fish inlet section 1, one or more rest pool chamber sections 5, two or more hump-shaped weir transition sections 2, and a double-layer overpass pool chamber section;

[0009] The end of the trumpet-shaped inlet section 1 is connected to one end of the double-deck interchange pool section through a hump weir-type transition section 2, the other end of the double-deck interchange pool section is connected to one end of the rest pool section 5 through a hump weir-type transition section 2, the other end of the rest pool section 5 is connected to another double-deck interchange pool section through a hump weir-type transition section 2, and two adjacent double-deck interchange pool sections are connected through the rest pool section 5 and the hump weir-type transition section 2. The double-deck interchange pool section includes a lower disc-shaped channel section 3 and an upper overflow weir section 4.

[0010] Specifically, the trumpet-shaped inlet section 1 includes a trumpet-shaped bottom plate 13 , a first side wall 11 and a second side wall 12 . The first side wall 11 and the second side wall 12 are located on the left and right sides of the trumpet-shaped bottom plate 13 .

[0011] Specifically, the hump weir-type transition section 2 includes a hump weir 21, a hump weir bottom plate 24, a first side wall 22 of the hump weir and a second side wall 23 of the hump weir. The first side wall 22 of the hump weir and the second side wall 23 of the hump weir are located on the left and right sides of the hump weir bottom plate 24. The hump weir 21 is connected to the middle position between the first side wall 22 of the hump weir and the second side wall 23 of the hump weir. The inner side of the hump weir 21 is connected to the upper overflow weir section 4, and the inner side of the hump weir bottom plate 24 is connected to the lower disc-shaped channel section 3.

[0012] Specifically, the lower disc-shaped channel section 3 includes an arc-shaped outer wall 31, an arc-shaped inner wall 34, a concave groove 32, a hollow disc-shaped bottom plate 33 and an arc-shaped support structure 35; the arc-shaped outer wall 31 and the arc-shaped inner wall 34 share the same center of the circle, the radius of the arc-shaped outer wall 31 is larger than the arc-shaped inner wall 34, the arc-shaped outer wall 31 and the arc-shaped inner wall 34 and the hollow disc-shaped bottom plate 33 are combined to form a lower pool chamber, and a plurality of concave grooves 32 are arranged in a circle at equal intervals in the lower pool chamber. The concave grooves 32 are arranged in an array and there are gaps between the arc-shaped outer wall 31 and the arc-shaped inner wall 34 on both sides. The arc-shaped outer wall 31 is provided with an outer wall water inlet gap and an outer wall water outlet gap. The arc-shaped inner wall 34 is provided with an inner wall water inlet gap and an inner wall water outlet gap at positions corresponding to the outer wall water inlet gap and the outer wall water outlet gap. An arc-shaped support structure 35 is installed at the inner wall water inlet gap and the inner wall water outlet gap, and the bottom of the upper overflow weir section 4 is placed on the arc-shaped support structure 35.

[0013] Specifically, the upper overflow weir section 4 includes a first side wall 41 of the overflow weir, a second side wall 42 of the overflow weir, a bottom plate 43 of the overflow weir and a hill-shaped weir 44; the first side wall 41 of the overflow weir, the second side wall 42 of the overflow weir and the bottom plate 43 of the overflow weir are combined to form an upper pool chamber, and multiple hill-shaped weirs 44 are arranged in a rectangular array in the upper pool chamber.

[0014] Specifically, the rest pool room section 5 includes a rest pool room bottom plate 53, a first side wall 51 and a second side wall 52 of the rest pool room, and a rest pool room water inlet and a rest pool room water outlet corresponding to each other are formed between the left-right symmetrical first side wall 51 and the second side wall 52 of the rest pool room.

[0015] Preferably, the angles on both sides of the inner side of the concave groove 32 are 120 degrees, and support columns are provided on both sides of the outer wall water inlet gap and the outer wall water outlet gap, and the bottom of the upper overflow weir section 4 is placed on the support columns.

[0016] Preferably, the end of the double-layer flyover fishway structure is a hump weir-type transition section 2 .

[0017] Preferably, the weir top of the hump weir 21 is connected to the upper overflow weir section 4, and the anti-isolated section is connected to the trumpet-shaped fish inlet section 1 or the rest pool chamber section 5.

[0018] Preferably, the upper portion of the hill-shaped weir 44 is hemispherical, the lower portion of the hemispherical shape is connected to a parabolic frustum, and the parabolic frustum is fixed on the overflow weir bottom plate 43 .

[0019] The beneficial effects of the present invention are:

[0020] This double-layer overpass fishway structure attracts fish in the river channel through the rapid current generated by the trumpet-shaped fish inlet at the downstream outlet of the fishway. The trumpet-shaped design can increase the impact range in the river channel, thereby attracting more fish to enter the fishway and smoothly swim upstream.

[0021] This double-layer interchange fishway structure uses a hump-shaped weir transition section to divide the main flow of the fishway chamber into an upper overflow weir area and a lower submerged flow area. The upper overflow weir uses a mound-shaped weir to simulate the rocky conditions of a natural river stream to further reduce the flow velocity in the chamber. The lower submerged flow area has a concave weir installed in the chamber to dissipate the energy of the water flow.

[0022] The double-layer overpass fishway structure forms a slow-flow area in the resting pool section by arranging flat-sloped rectangular resting pool sections between two double-layer overpass pool sections. Fish can take a short rest in the slow-flow area when swimming upstream, thereby improving the fish passing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the main view of the overall structure of the fishway;

[0024] Figure 2 This is an overhead view of the fishway;

[0025] Figure 3 It is a structural diagram of the trumpet-shaped inlet section;

[0026] Figure 4 It is a structural diagram of the hump weir type transition section;

[0027] Figure 5 This is a schematic diagram of the three-dimensional structure of the lower disc-shaped channel section;

[0028] Figure 6 This is a top view of the lower disc-shaped channel section;

[0029] Figure 7 Schematic diagram of the three-dimensional structure of the upper overflow weir section;

[0030] Figure 8 This is a top view of the upper overflow weir section;

[0031] Figure 9 This is a schematic diagram of the three-dimensional structure of the rest pool room section. DETAILED DESCRIPTION

[0032] The embodiments of the present invention are now clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts are within the scope of protection of the present invention.

[0033] It should also be noted that, for ease of description, only the portions relevant to the invention are shown in the accompanying drawings. Terms such as "first" and "second" in the present invention are provided for the convenience of describing the technical solution of the present invention and do not have any specific limiting effect. They are general references and do not constitute a limitation on the technical solution of the present invention.

[0034] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the present invention.

[0035] Example 1: Please refer to Figure 1-9 A double-deck interchange fishway structure comprises a trumpet-shaped inlet section 1, one or more rest pool sections 5, two or more hump-shaped weir transition sections 2, and a double-deck interchange pool section;

[0036] The end of the trumpet-shaped inlet section 1 is connected to one end of the double-deck interchange pool section through a hump weir type transition section 2, the other end of the double-deck interchange pool section is connected to one end of the rest pool section 5 through a hump weir type transition section 2, the other end of the rest pool section 5 is connected to another double-deck interchange pool section through a hump weir type transition section 2, and so on. According to actual conditions, the number of double-deck interchange pool sections can be multiple, and a rest pool is connected between every two double-deck interchange pool sections. Two adjacent double-deck interchange pool sections are connected by a rest pool section 5 and a hump weir type transition section 2. The double-deck interchange pool section includes a lower disc-shaped channel section 3 and an upper overflow weir section 4.

[0037] The hump weir transition section 2 connects the trumpet-shaped inlet section 1 and the double-deck interchange chamber section, and at the same time connects the double-deck interchange chamber section and the rest chamber section 5. The rest chamber section 5 connects two double-deck interchange chamber sections through the hump weir transition section 2.

[0038] Further, if Figure 3 As shown, the trumpet-shaped inlet section 1 includes a trumpet-shaped bottom plate 13, a first side wall 11, and a second side wall 12. The first side wall 11 and the second side wall 12 are located on the left and right sides of the trumpet-shaped bottom plate 13. The trumpet-shaped inlet section 1 forms a large rapids area at the entrance of the fishway through its open trumpet-shaped inlet, attracting fish in the downstream river channel and improving fish attracting efficiency.

[0039] Furthermore, the hump-shaped weir transition section 2 includes a hump weir 21, a hump weir base plate 24, a first hump weir sidewall 22, and a second hump weir sidewall 23. The first and second hump weir sidewalls 22 and 23 are located on the left and right sides of the hump weir base plate 24. The hump weir 21 is connected to the middle position between the first and second hump weir sidewalls 22 and 23. The inner side of the hump weir 21 abuts the upper overflow weir section 4, while the inner side of the hump weir base plate 24 abuts the lower disc-shaped channel section 3. The hump weir transition section 2 divides the water flow in the fishway into an upper overflow area and a lower submerged flow area via the hump weir 21. The hump-shaped design fully considers the overflow environment formed in the natural river channel.

[0040] Furthermore, the lower disc-shaped channel section 3 includes an arc-shaped outer wall 31, an arc-shaped inner wall 34, a concave groove 32, a hollow disc-shaped bottom plate 33 and an arc-shaped support structure 35; the arc-shaped outer wall 31 and the arc-shaped inner wall 34 share the same center of the circle, the radius of the arc-shaped outer wall 31 is larger than the arc-shaped inner wall 34, the arc-shaped outer wall 31 and the arc-shaped inner wall 34 and the hollow disc-shaped bottom plate 33 are combined to form a lower pool chamber, and a plurality of concave grooves 32 are arranged in a circle at equal intervals in the lower pool chamber. The concave grooves 32 are arranged in a circular array, with gaps between the arc-shaped outer wall 31 and the arc-shaped inner wall 34 on both sides. The arc-shaped outer wall 31 is provided with an outer wall water inlet and an outer wall water outlet gap. The arc-shaped inner wall 34 is provided with inner wall water inlet and outlet gaps at locations corresponding to the outer wall water inlet and outlet gaps. Arc-shaped support structures 35 are installed at the inner wall water inlet and outlet gaps, and the bottom of the upper overflow weir section 4 rests on the arc-shaped support structures 35. The presence of these concave grooves 32 in the lower disc-shaped channel section 3 obstructs the water flow within the fishway, thereby reducing the water flow rate. The arc-shaped support structures 35 provide structural support for the upper overflow weir section 4.

[0041] Further, if Figure 6 、 Figure 7 As shown, the upper overflow weir section 4 includes a first overflow weir side wall 41, a second overflow weir side wall 42, an overflow weir bottom plate 43, and a mound-shaped weir 44. The first overflow weir side wall 41, the second overflow weir side wall 42, and the overflow weir bottom plate 43 form an upper pool chamber. Multiple mound-shaped weirs 44 are arranged in a rectangular array in the upper pool chamber. Multiple mound-shaped weirs 44 limit the flow of water in the upper pool chamber. The size design of the mound-shaped weirs 44 can be further adjusted according to actual conditions and economic conditions. The upper pool chamber of the upper overflow weir section 4 is equipped with a number of mound-shaped weirs 44 to simulate stream stones in a natural environment, thereby meeting the water flow conditions in the upper pool chamber. The mound-shaped weirs 44 arranged in a rectangular array in the upper overflow weir section 4 form a stable flow state. The water flow conditions in the upper pool chamber are in line with the habits of fish that like to jump and prefer to live on the surface.

[0042] In this embodiment, the bottom slope of the double-deck interchange chamber sections 3 and 4 is set to 1 / 50 to 1 / 150, which can effectively control the flow rate and flow velocity in the fishway.

[0043] Furthermore, the rest pool section 5 includes a rest pool bottom plate 53, a first side wall 51 and a second side wall 52 of the rest pool, and a corresponding rest pool water inlet and rest pool water outlet are formed between the left-right symmetrical first side wall 51 and the second side wall 52 of the rest pool. Figure 9 As shown, the first side wall 51 and the second side wall 52 of the rest pool chamber are protruding to the left and right sides. The rest pool chamber section 5 forms a low flow rate area between the two double-layer interchange chamber sections by setting a flat slope at the bottom, providing a good rest environment for the fish in the fishway and restoring their physical strength so that they can smoothly go upstream through the fishway later.

[0044] Furthermore, the concave groove 32 has an inner angle of 120 degrees on both sides, which can effectively slow down the water flow in the lower pool, play a guiding role in the water flow in the lower pool, and form a clear main flow in the lower pool, so that fish in the pool can swim upstream smoothly along the main flow. The size design of the concave groove 32 can be further adjusted according to actual conditions and economic conditions.

[0045] Furthermore, support columns are provided on both sides of the outer wall water inlet gap and the outer wall water outlet gap, and the bottom of the upper overflow weir section 4 is placed on the support columns. The support columns also form structural support for the upper overflow weir section 4.

[0046] Furthermore, no matter how many double-layer interchange chamber sections are connected, the end of the entire double-layer interchange fishway structure is a hump weir-type transition section 2, which can divert the water flow into the double-layer interchange chamber section and converge the water flow out of the double-layer interchange chamber. The hump weir-shaped design can prevent the fish from coming into contact with the fishway structure when swimming to the upper chamber, thereby causing harm.

[0047] Furthermore, the top of the hump weir 21 is connected to the upper overflow weir section 4, and the anti-arc section is connected to the trumpet-shaped inlet section 1 or the rest pool section 5. The anti-arc section structure makes the water flow in or out of the pool chamber smooth and better connected with the rest pool section or trumpet-shaped inlet water flow.

[0048] Furthermore, the upper portion of the hill-shaped weir 44 is hemispherical, the lower portion of the hemispherical shape is connected to a parabolic frustum, and the parabolic frustum is fixed on the overflow weir bottom plate 43 .

[0049] The working principle of the present invention is as follows: the upstream water flows into the fishway from the trumpet-shaped inlet section 1, and the main stream is diverted when passing through the hump-shaped transition section 2. After the diversion, part of the main stream passes through the upper overflow weir section 4, and the other part passes through the lower disc-shaped channel section 3; due to the diversion effect of the main stream, the upper overflow weir section 4 will maintain an overflow state due to the shallow water depth, and the lower disc-shaped channel section 3 will maintain a submerged flow state, so that the fishway is divided into an upper overflow area and a lower submerged flow area. The upper overflow area is provided with a concave groove 32 with a flow-limiting structure, and the lower submerged flow area is provided with a mound-shaped weir 44 with a flow-limiting structure, which further reduces the flow velocity in the fishway and controls the flow, thereby forming attraction at the fish inlet of the downstream fishway. Downstream fish sense their preferred flow pattern in the trumpet-shaped inlet section 1 and are attracted to enter the upper and lower fishways through the hump-shaped transition section 2 and swim upstream. Then, they pass through the hump-shaped transition section 2 again to enter the resting pool section 5. Then, they continue to pass through several double-layer interchange pool sections and the resting pool section 5 and finally swim upstream smoothly. The double-layer interchange design provides choices for downstream fish with different preferences, thereby improving fish passing efficiency.

[0050] Compared with other types of fishway structures, the present invention has the following advantages: the fishway structure can adapt to different flow rates and water level changes and divert the water flow in the pool chamber, and can divide the water flow in the pool chamber into two different flow zones, thereby attracting fish with different swimming abilities and living habits, and meeting the upstream conditions of different fish.

[0051] The above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, additions or substitutions made by ordinary technicians in this technical field within the scope of the present invention, such as adjustments to the fishway concrete and backfill structure or foundation treatment method, to reduce the amount of slope support treatment work and reduce the slope protection and fishway structural types that disturb the protected objects, should all fall within the scope of protection of the present invention.

Claims

1. A double-layer overpass fishway structure, characterized by: It includes a trumpet-shaped inlet section (1), one or more rest pool sections (5), two or more hump-shaped weir transition sections (2), and a double-layer interchange pool section; The end of the trumpet-shaped inlet section (1) is connected to one end of the double-layer interchange pool section through a hump weir-type transition section (2), the other end of the double-layer interchange pool section is connected to one end of the rest pool section (5) through a hump weir-type transition section (2), the other end of the rest pool section (5) is connected to another double-layer interchange pool section through a hump weir-type transition section (2), and two adjacent double-layer interchange pool sections are connected through the rest pool section (5) and the hump weir-type transition section (2), and the double-layer interchange pool section includes a lower disc-shaped channel section (3) and an upper overflow weir section (4); The hump weir type transition section (2) includes a hump weir (21), a hump weir bottom plate (24), a first side wall (22) of the hump weir and a second side wall (23) of the hump weir. The first side wall (22) of the hump weir and the second side wall (23) of the hump weir are located on the left and right sides of the hump weir bottom plate (24). The hump weir (21) is connected to the middle position between the first side wall (22) of the hump weir and the second side wall (23) of the hump weir. The inner side of the hump weir (21) is connected to the upper overflow weir section (4), and the inner side of the hump weir bottom plate (24) is connected to the lower disc-shaped channel section (3). The lower disc-shaped channel section (3) comprises an arc-shaped outer side wall (31), an arc-shaped inner side wall (34), a concave groove (32), a hollow disc-shaped bottom plate (33) and an arc-shaped support structure (35); the arc-shaped outer side wall (31) and the arc-shaped inner side wall (34) share the same center, the radius of the arc-shaped outer side wall (31) is greater than the radius of the arc-shaped inner side wall (34), the arc-shaped outer side wall (31) and the arc-shaped inner side wall (34) and the hollow disc-shaped bottom plate (33) are combined to form a lower pool chamber, and a plurality of concave grooves (32) are arranged in an equal manner in the lower pool chamber. The concave grooves (32) are arranged in a circular array at intervals, and gaps are left between the two sides of the concave grooves (32) and the arc-shaped outer wall (31) and the arc-shaped inner wall (34). The arc-shaped outer wall (31) is provided with an outer wall water inlet gap and an outer wall water outlet gap. The arc-shaped inner wall (34) is provided with an inner wall water inlet gap and an inner wall water outlet gap at positions corresponding to the outer wall water inlet gap and the outer wall water outlet gap. An arc-shaped support structure (35) is installed at the inner wall water inlet gap and the inner wall water outlet gap. The bottom of the upper overflow weir section (4) is placed on the arc-shaped support structure (35). The upper overflow weir section (4) includes a first overflow weir side wall (41), a second overflow weir side wall (42), an overflow weir bottom plate (43), and a hill-shaped weir (44); the first overflow weir side wall (41), the second overflow weir side wall (42), and the overflow weir bottom plate (43) are combined to form an upper pool chamber, and a plurality of hill-shaped weirs (44) are arranged in a rectangular array in the upper pool chamber; The upper portion of the hill-shaped weir (44) is hemispherical, and the lower portion of the hemispherical shape is connected to a parabolic frustum, which is fixed on the overflow weir bottom plate (43).

2. The double-deck overpass fishway structure according to claim 1, characterized in that: The trumpet-shaped inlet section (1) comprises a trumpet-shaped bottom plate (13), a first side wall (11) and a second side wall (12), wherein the first side wall (11) and the second side wall (12) are located on the left and right sides of the trumpet-shaped bottom plate (13).

3. The double-layer overpass fishway structure according to claim 1, characterized in that: The rest pool section (5) comprises a rest pool bottom plate (53), a first side wall (51) and a second side wall (52) of the rest pool, wherein a rest pool water inlet and a rest pool water outlet corresponding to each other are formed between the left-right symmetrical first side wall (51) and the second side wall (52).

4. The double-layer overpass fishway structure according to claim 1, characterized in that: The angles on both sides of the inner side of the concave groove (32) are both 120 degrees. Support columns are provided on both sides of the water inlet gap and the water outlet gap of the outer wall, and the bottom of the upper overflow weir section (4) is placed on the support columns.

5. The double-layer overpass fishway structure according to claim 1, characterized in that: The end of the double-layer interchange fishway structure is a hump weir-type transition section (2).

6. The double-layer overpass fishway structure according to claim 1, characterized in that: The weir crest of the hump weir (21) is connected to the upper overflow weir section (4), and the anti-arc section is connected to the trumpet-shaped inlet section (1) or the rest pool chamber section (5).

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