Ecological flow releasing facility with fishway and construction method thereof

Abstract

The present application belongs to the technical field of hydraulic engineering and environmental protection engineering facilities, and particularly relates to an ecological flow releasing facility with a fishway and a construction method thereof. The present application is directed to the reconstruction and expansion of hydraulic engineering with ecological requirements. The fishway and the ecological flow releasing system adopt a short tunnel around dam scheme, which has little influence on other buildings of the hub. Rock plug is used for water retaining, and the installation of the water retaining gate is completed before the flood season, thereby avoiding the risk of flood control during the construction period due to the increase of the retaining and releasing water buildings caused by the reconstruction and expansion. The overall layout of the fishway engineering and the ecological flow releasing facility is considered, the tunnel section adopts the layout of the fishway on the top and the ecological releasing pipe on the bottom, the tunnel section type is beneficial to the stability of the surrounding rock, the construction difficulty is small, and the excavation and support amount is small. The tunnel section adopts a sunlight fiber optic introduction system for lighting, which can make the fishway tunnel section more close to the natural conditions, and the adverse effects of the fishway tunnel section engineering on fish migration are minimized.

Description

Technical Field

[0001] This invention belongs to the technical field of water conservancy engineering and environmental protection engineering facilities, specifically relating to an ecological flow release facility with fish passage and its construction method. Background Technology

[0002] Currently, some early-built hydropower stations lack dedicated ecological flow release facilities, resulting in substandard downstream ecological base flow and the absence of dedicated fish migration channels, thus impacting fish habitats and populations. This further damages the entire food chain. Based on current environmental protection requirements, it is necessary to renovate and expand existing water conservancy projects with ecological needs, constructing new fish passages and ecological flow release facilities.

[0003] However, for existing projects requiring ecological modifications and expansions, such as fishways and ecological flow release facilities, the high water level in the reservoir area, close to the normal storage level, makes it impossible to lower the water level. This results in significant design and construction challenges for the fishway outlet and the ecological flow release facility inlet. Modifying hydraulic structures and their interconnections with existing structures presents significant design and construction difficulties, substantial impacts on other structures, high requirements for upstream cofferdam construction, high flood control risks, and a significant increase in project investment.

[0004] Based on this, the inventors hope to design an ecological flow release facility with fish passages and its construction method to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned problems existing in the traditional technology and to provide an ecological flow release facility with fish passage and its construction method.

[0006] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution:

[0007] This invention provides an ecological flow release facility with a fishway, including a fishway inlet, a downstream section of the fishway, a tunnel section of the fishway and the ecological flow release facility, a fishway floodgate, an upstream section of the fishway, a fishway outlet, an inlet of the ecological flow release facility, an emergency maintenance gate for the ecological flow release facility, an ecological discharge pipe, an ecological flow energy dissipation and regulating valve, a tunnel section of the fishway, and a solar fiber optic lighting system.

[0008] The fishway outlet and the inlet of the ecological flow release facility are located below the normal water level of the upper reservoir area; the fishway and ecological flow release facility tunnel section is a shared tunnel for the fishway and the ecological flow release pipe, with the ecological flow release pipe located below the fishway in the tunnel section, separated by a reinforced concrete slab; the ecological flow energy dissipation regulating valve is located at the end of the ecological flow release pipe; the fishway floodgate, the inlet of the ecological flow release facility, and the emergency maintenance gate of the ecological flow release facility are located at the upstream outlet of the fishway and ecological flow release facility tunnel section; the solar fiber optic lighting system is located on the top arch of the fishway and ecological flow release facility tunnel section; the end outlet of the ecological flow release pipe is located upstream of the fishway inlet; a downstream section of the fishway is provided between the fishway inlet and one end of the fishway and ecological flow release facility tunnel section; fishway outlets are provided at both ends of the upstream section of the fishway, and the end of the upstream section of the fishway near the fishway floodgate is connected to the other end of the fishway and ecological flow release facility tunnel section.

[0009] Furthermore, in the ecological flow release facility with fish passages as described above, the total length of the fish passage and the tunnel section of the ecological flow release facility is ≤300m.

[0010] Furthermore, in the ecological flow release facility with fish passages as described above, the ratio of height H to width W in the tunnel cross-sectional dimensions of the fish passage and the tunnel section of the ecological flow release facility is ≤2.5.

[0011] Furthermore, in the ecological flow release facility with fish passages as described above, the fish passage and the ecological release pipe are independent of each other, and the outlet of the ecological flow release facility is located upstream of the fish passage inlet.

[0012] Furthermore, the ecological flow release facility with fishway described above also includes an upstream cofferdam, a dam, and a hydropower plant. The upstream section of the fishway is located close to the upstream cofferdam, and the tunnel section of the fishway and ecological flow release facility is located on the side of the hydropower plant away from the dam.

[0013] The present invention also provides a construction method for an ecological flow release facility with a fishway, comprising the following steps:

[0014] S1. Analyze, calculate and determine the relationship curve between water level and guarantee rate in the reservoir area. Take the water level with a guarantee rate of 90% to determine the minimum design water level H1 (m) at the fishway outlet. Take the bottom elevation of the first outlet of the fishway A1 = H1 - 1 (m).

[0015] S2. Based on the design of a fully pressurized ecological release tunnel, determine the exit elevation A3 (m) of the tunnel section for the fishway and ecological flow release facilities.

[0016] S3. Considering the ecological requirements of fish, the length L of the tunnel section should be as short as possible and should not exceed 300m. In order to make the fish passage conditions in the fish passage tunnel section closer to the natural conditions and to minimize the adverse effects of the fish passage and ecological flow discharge facility tunnel section on fish migration, a solar fiber optic lighting system is installed in the tunnel top area to provide lighting for the tunnel.

[0017] S4. Based on the cross-section of the ecological release pipe and the cross-section of the fishway in the tunnel section, determine the cross-sectional dimensions of the fishway and the tunnel section of the ecological flow release facility. The ratio of the tunnel height (H) to width (W) should not exceed 2.5. The fishway in the tunnel section is located above the ecological release pipe. The selection of the ecological release pipe route downstream of the tunnel section of the fishway and the ecological flow release facility should make full use of the excavation layout of the downstream section of the fishway, and the routes of the two should overlap as much as possible to reduce the amount of excavation and backfilling work for the ecological release facility. An ecological flow energy dissipation regulating valve is installed at the end of the ecological release pipe, and the outlet is located upstream of the fishway inlet.

[0018] S5. The upstream section of the fishway should fully consider the topographic and geological conditions and determine its type by using rock anchors, pile foundations, or excavation and filling methods.

[0019] S6. Under the condition of meeting the functional objectives of the hub reservoir, joint operation with upstream and downstream cascade reservoirs shall be adopted to minimize the reservoir water level during the construction period of the reconstruction and expansion project. The design top elevation of the cofferdam during the construction period shall be determined through flood control calculations.

[0020] S7. Based on the tunnel cross-sectional dimensions determined in S4, the ratio of rock plug thickness to bottom diameter is selected and controlled at 1 to 1.5. After the first flood season in the first year of construction, the reservoir water level is lowered by joint scheduling of cascade reservoirs. The upstream cofferdam is filled, and the downstream section of the tunnel section of the fishway and ecological flow release facilities is constructed. After the fishway floodgate and the emergency maintenance gate of the ecological flow release facilities are installed, the rock plug is constructed.

[0021] Furthermore, in step S2, the specific method for determining the exit elevation A3 (m) of the fishway and ecological flow discharge facility tunnel section is as follows:

[0022] 1) The formula is used under the operating conditions of the lowest operating water level H2 (m) and the maximum outflow ecological flow Q (m³ / s) in the reservoir area. Determine the minimum submergence depth S (m) of the inlet of the ecological flow release facility;

[0023] 2) Determine the height d of the emergency maintenance gate opening of the ecological flow discharge facility, the gate opening width b, and the average flow velocity of the gate opening cross-section according to the full-pressure flow design. (m / s);

[0024] 3) Determine the elevation of the bottom plate of the inlet of the ecological flow discharge facility: A2 = H2 - Sd (m);

[0025] 4) Determine the exit elevation of the fishway and ecological flow discharge facility tunnel section A3 = min(A1, A2).

[0026] Furthermore, the coefficient C is taken as 0.55 when the water flow is symmetrical and in the positive direction, and as 0.73 in other cases.

[0027] The beneficial effects of this invention are:

[0028] 1. For water conservancy projects undergoing renovation and expansion with ecological requirements, the fishway and ecological flow release system adopt a short tunnel bypass dam scheme, which has virtually no impact on other structures in the project. Water is blocked by rock plugs, and the installation of the floodgates is completed before the flood season, avoiding the increased flood risks during the construction period caused by the renovation and expansion of the water-blocking and release structures.

[0029] 2. Taking into account the overall layout of the fishway project and the ecological flow discharge facility, the tunnel section adopts a layout with the fishway above and the ecological discharge pipe below. The tunnel cross-section shape is conducive to the stability of the surrounding rock, with less construction difficulty and less excavation and support.

[0030] 3. The length of the tunnel section should be as short as possible, not exceeding 300m. The use of a solar fiber optic lighting system can make the fish passage conditions in the fish passage tunnel section closer to natural conditions, thus minimizing the adverse effects of the fish passage tunnel section project on fish migration.

[0031] 4. The ecological flow discharge facility is designed with pressure and is equipped with a flow regulating and energy dissipation valve at the end. It can accurately control the discharge flow and dissipate the energy of the discharged water flow, making it flexible and controllable.

[0032] 5. While ensuring that the function of the reservoir hub is not affected, make full use of the joint operation of cascade reservoirs to lower the water level during the construction period and reduce the difficulty of construction.

[0033] 6. The fishway and the ecological flow release system are independent of each other and do not affect each other. Furthermore, the ecological flow can provide water for fish to be attracted by the fishway at a certain time of the year.

[0034] Of course, any product implementing this invention does not necessarily need to achieve all of the above advantages at the same time. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic plan view of the ecological flow release facility of the present invention;

[0037] Figure 2 This is a schematic cross-sectional view of the tunnel section of the ecological flow release facility of the present invention;

[0038] Figure 3 This is a schematic longitudinal section of the inlet section of the ecological flow release facility of the present invention;

[0039] Figure 4 This is a water level-guarantee rate curve during the fish passage period in an embodiment of the present invention. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] The relevant embodiments of the present invention are as follows:

[0042] Please see Figures 1-3 This embodiment provides an ecological flow release facility with a fishway, including a fishway inlet 1, a downstream section of the fishway 2, a tunnel section of the fishway and ecological flow release facility 3, a fishway floodgate 4, an upstream section of the fishway 5, a fishway outlet 6, an inlet of the ecological flow release facility 7, an emergency maintenance gate of the ecological flow release facility 8, an upstream cofferdam 9, a dam 10, a hydropower station building 11, an ecological discharge pipe 12, an ecological flow energy dissipation and regulating valve 13, a tunnel section of the fishway 14, and a solar fiber optic lighting system 15.

[0043] In this embodiment, the fishway outlet 6 and the ecological flow release facility inlet 7 are located below the normal water level of the upper reservoir area; the fishway and ecological flow release facility tunnel section 3 is a shared tunnel for the tunnel section fishway 14 and the ecological release pipe 12, with the ecological release pipe 12 located below the tunnel section fishway 14, and the two are separated by a reinforced concrete slab; the ecological flow energy dissipation regulating valve 13 is located at the end of the ecological release pipe 12. The fishway floodgate 4, the inlet 7 of the ecological flow release facility, and the emergency maintenance gate 8 of the ecological flow release facility are located at the upstream outlet of the fishway and ecological flow release facility tunnel section 3; the solar fiber optic lighting system 15 is located at the top arch of the fishway and ecological flow release facility tunnel section 3; the end outlet of the ecological discharge pipe 12 is located upstream of the fishway inlet 1; a downstream section 2 of the fishway is set between the fishway inlet 1 and one end of the fishway and ecological flow release facility tunnel section 3; fishway outlets 6 are set at both ends of the upstream section 5 of the fishway, and the end of the upstream section 5 near the fishway floodgate 4 is connected to the other end of the fishway and ecological flow release facility tunnel section 3. The upstream section 5 of the fishway is set near the upstream cofferdam 9, and the fishway and ecological flow release facility tunnel section 3 is set in the area on the side of the hydropower plant 11 away from the dam 10.

[0044] In this embodiment, the total length of the fishway and ecological flow discharge facility tunnel section 3 is ≤300m. The ratio of height H to width W in the tunnel cross-sectional dimensions of the fishway and ecological flow discharge facility tunnel section 3 is ≤2.5.

[0045] In this embodiment, the fishway and the ecological discharge pipe 12 are independent of each other, and the inlet 7 of the ecological flow discharge facility is located upstream of the fishway inlet 1.

[0046] This embodiment also provides a construction method for an ecological flow release facility with a fishway, including the following steps:

[0047] S1. Analyze, calculate, and determine the reservoir water level-guarantee rate relationship curve, such as... Figure 4 As shown, the minimum design water level of the fishway outlet is determined to be 223.8 m, with a water level guaranteeing 90% of the water level. The elevation of the bottom plate of the first outlet of the upstream section 5 of the fishway is A1 = 223.8 - 1 = 222.8 m.

[0048] S2. Based on the design of a fully pressurized ecological discharge tunnel, under the operating conditions of the lowest operating water level in the reservoir H2 = 223.8 m and the maximum outflow ecological flow Q = 19.15 m³ / s, the formula is adopted. In the formula, the coefficient C = 0.55 is used for symmetrical water intake design; the height d of the gate opening of the ecological flow discharge facility accident inspection gate 8 is taken as 2.5m and the width b of the gate opening is taken as 2.5m, based on the fully pressurized flow design; the average flow velocity of the gate opening cross-section is... m / s; Determine the minimum submergence depth at the inlet of the ecological flow discharge facility. m; Determine the bottom elevation of the inlet 7 of the ecological flow release facility as A2=H2-Sd=223.8-2.7-2.5=218.6m; Based on the relative relationship between A1 and A2, take the smaller of the two as the exit elevation of the fishway and the tunnel section 3 of the ecological flow release facility as A3=A2=218.6m;

[0049] S3. Considering the ecological requirements of fish, the length L of the fishway and ecological flow release facility tunnel section 3 is set according to the site layout and the situation of the entrance and exit points. In order to make the fish passage conditions of the fishway tunnel section closer to the natural conditions and to minimize the adverse effects of the fishway and ecological flow release facility tunnel section 3 on fish migration, a solar fiber optic lighting system 15 is installed in the top area of ​​the tunnel to provide lighting for the fishway and ecological flow release facility tunnel section 3.

[0050] S4. Based on the cross-sectional dimensions of the ecological release pipe 12 and the fishway 14 in the tunnel section, the cross-sectional dimensions of the fishway and ecological flow release facility tunnel section 3 are determined. The tunnel height H = 7.8m and width W = 3.8m are taken, with the fishway 14 in the tunnel section located above and the ecological release pipe 12 located below. The route selection of the ecological release pipe 12 downstream of the fishway and ecological flow release facility tunnel section 3 makes full use of the excavation layout of the downstream section 2 of the fishway, and the routes of the two overlap as much as possible to reduce the amount of excavation and backfilling work for the ecological release facility. An ecological flow energy dissipation regulating valve 13 is installed at the end of the ecological release pipe 12, and the outlet is located upstream of the fishway inlet 1.

[0051] S5, the upstream section 5 of the fishway should fully consider the topographic and geological conditions and determine its type by adopting rock anchors, pile foundations or excavation and filling methods;

[0052] S6. Under the condition of meeting the functional objectives of the hub reservoir (such as irrigation, water supply and power generation), joint operation with upstream and downstream cascade reservoirs shall be adopted to minimize the reservoir water level during the construction period of the reconstruction and expansion project. After verification, the reservoir water level can be reduced by 5m under the condition of ensuring the reservoir function. After flood control calculation, the design top elevation of the cofferdam during the construction period is reduced by 4.5m.

[0053] S7. Based on the tunnel cross-sectional dimensions determined in S4, the ratio of rock plug thickness to bottom diameter is selected according to a control of 1 to 1.5. A reserved rock plug length of 5m is determined based on upstream and downstream head calculations and construction conditions. In the first year of construction, after the flood season, a cascade reservoir joint operation is used to lower the reservoir water level. Construction is then carried out on the upstream cofferdam 9, the downstream section of the fishway and ecological flow release facility tunnel section 3, etc. After the fishway floodgate 4 and the ecological flow release facility emergency maintenance gate 8 are installed, construction is carried out on the remaining rock plugs.

[0054] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A construction method of an ecological flow releasing facility having a fishway, characterized by, The ecological flow release facility with fishway includes a fishway inlet, a downstream section of the fishway, a tunnel section of the fishway and ecological flow release facility, a fishway floodgate, an upstream section of the fishway, a fishway outlet, an ecological flow release facility inlet, an ecological flow release facility emergency maintenance gate, an ecological discharge pipe, an ecological flow energy dissipation and regulating valve, a tunnel section of the fishway, and a solar fiber optic lighting system. The fishway outlet and the ecological flow release facility inlet are located below the normal water level of the upper reservoir. The tunnel section of the fishway and ecological flow release facility is a shared tunnel for both the tunnel section of the fishway and the ecological discharge pipe, with the ecological discharge pipe located below the tunnel section of the fishway, separated by a reinforced concrete slab. The flow dissipation valve is located at the end of the ecological discharge pipe; the fishway floodgate, the inlet of the ecological flow discharge facility, and the emergency maintenance gate of the ecological flow discharge facility are located at the upstream outlet of the fishway and ecological flow discharge facility tunnel section; the solar fiber optic lighting system is located at the top arch of the fishway and ecological flow discharge facility tunnel section; the end outlet of the ecological discharge pipe is located upstream of the fishway inlet; a downstream section of the fishway is provided between the fishway inlet and one end of the fishway and ecological flow discharge facility tunnel section; fishway outlets are provided at both ends of the upstream section of the fishway; and the end of the upstream section of the fishway near the fishway floodgate is connected to the other end of the fishway and ecological flow discharge facility tunnel section. The construction method includes the following steps: S1. Analyze, calculate and determine the relationship curve between water level and guarantee rate in the reservoir area. Take the water level with a guarantee rate of 90% to determine the minimum design water level H1 (m) at the fishway outlet. Take the bottom elevation of the first outlet of the fishway A1 = H1 - 1 (m). S2. Based on the design of a fully pressurized ecological release tunnel, determine the exit elevation A3 (m) of the tunnel section for the fishway and ecological flow release facilities. S3. Considering the ecological requirements of fish, the length L of the tunnel section should be as short as possible and should not exceed 300m. In order to make the fish passage conditions in the fish passage tunnel section closer to the natural conditions and to minimize the adverse effects of the fish passage and ecological flow discharge facility tunnel section on fish migration, a solar fiber optic lighting system is installed in the tunnel top area to provide lighting for the tunnel. S4. Based on the cross-section of the ecological release pipe and the cross-section of the fishway in the tunnel section, determine the cross-sectional dimensions of the fishway and the tunnel section of the ecological flow release facility. The ratio of the tunnel height (H) to width (W) should not exceed 2.

5. The fishway in the tunnel section is located above the ecological release pipe. The selection of the ecological release pipe route downstream of the tunnel section of the fishway and the ecological flow release facility should make full use of the excavation layout of the downstream section of the fishway, and the routes of the two should overlap as much as possible to reduce the amount of excavation and backfilling work for the ecological release facility. An ecological flow energy dissipation regulating valve is installed at the end of the ecological release pipe, and the outlet is located upstream of the fishway inlet. S5. The upstream section of the fishway should fully consider the topographic and geological conditions and determine its type by using rock anchors, pile foundations, or excavation and filling methods. S6. Under the condition of meeting the functional objectives of the hub reservoir, joint operation with upstream and downstream cascade reservoirs shall be adopted to minimize the reservoir water level during the construction period of the reconstruction and expansion project. The design top elevation of the cofferdam during the construction period shall be determined through flood control calculations. S7. Based on the tunnel cross-sectional dimensions determined in S4, the ratio of rock plug thickness to bottom diameter is selected and controlled at 1 to 1.

5. After the first flood season in the first year of construction, the reservoir water level is lowered by joint scheduling of cascade reservoirs. The upstream cofferdam is filled, and the downstream section of the tunnel section of the fishway and ecological flow release facilities is constructed. After the fishway floodgate and the emergency maintenance gate of the ecological flow release facilities are installed, the rock plug is constructed.

2. The construction method according to claim 1, characterized in that, The total length of the fishway and ecological flow discharge facility tunnel section is ≤300m.

3. The construction method according to claim 1, characterized in that, The ratio of height (H) to width (W) in the tunnel cross-sectional dimensions of the fishway and ecological flow discharge facility tunnel section is ≤2.

5.

4. The construction method according to claim 1, characterized in that, The fishway and the ecological discharge pipe are independent of each other, and the outlet of the ecological flow discharge facility is located upstream of the fishway inlet.

5. The construction method according to claim 1, characterized in that, It also includes upstream cofferdams, dams and hydropower plant buildings. The upstream section of the fishway is located close to the upstream cofferdam, and the tunnel section of the fishway and ecological flow release facilities is located on the side of the hydropower plant building away from the dam.

6. The construction method according to claim 1, characterized in that, In step S2, the specific method for determining the exit elevation A3 (m) of the fishway and ecological flow discharge facility tunnel section is as follows: 1) The formula is used under the operating conditions of the lowest operating water level H2 (m) and the maximum outflow ecological flow Q (m³ / s) in the reservoir area. Determine the minimum submergence depth S (m) of the inlet of the ecological flow release facility; 2) Determine the height d of the emergency maintenance gate opening of the ecological flow discharge facility, the gate opening width b, and the average flow velocity of the gate opening cross-section according to the full-pressure flow design. (m / s); 3) Determine the elevation of the bottom plate of the inlet of the ecological flow discharge facility: A2 = H2 - Sd (m); 4) Determine the exit elevation of the fishway and ecological flow discharge facility tunnel section A3 = min(A1, A2).

7. The construction method according to claim 6, characterized in that, The coefficient C is taken as 0.55 when the water flow is symmetrical and in the positive direction, and as 0.73 in other cases.

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