Fishway structure and construction and design method

Abstract

The invention relates to the field of migration fishways, in particular to a fishway structure and a construction and design method. The fishway structure comprises a migration channel, a plurality of rows of pile structures are arranged at the bottom of the migration channel, each row is provided with at least two pile structures at intervals, and the adjacent rows of pile structures are staggered in the length direction of the migration channel. According to the fishway structure, the pile structures are arranged at the bottom of the migration channel, the adjacent rows of pile structures are staggered in the length direction of the migration channel, climbing assistance is provided for eels, and meanwhile, compared with a bristle base, the pile structures do not have bristles, so that the situation of chipping blockage does not exist, and cleaning is easy. Meanwhile, the pile structure can increase friction along the way, water flow hedging and diffusion are used for dissipating energy, and the effects of improving the flow state and reducing the flow speed of the migration channel are achieved.

Description

Technical Field

[0001] The present invention relates to the field of migratory fishways, and in particular to a fishway structure, construction and design method. Background Art

[0002] Eel, also known as eel, is a very important migratory fish in estuaries. It has the characteristics of sea and river migration and needs to migrate in brackish and fresh water to complete its life cycle. When building a hub on a canal, the hub lock fish passing facilities need to be specially equipped with eel ways. For the migration of eels, foreign eel ways usually include an inclined channel equipped with a base such as bristles to facilitate climbing.

[0003] Eel-specific bristle bases have been used in some cases abroad and have been proven to be effective, such as the eel track at the Zeltingen Dam on the Mosel River in Germany. However, the bristles are easily clogged with debris and are difficult to clean. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art that the bristle base is applied to eel paths, the bristles are easily clogged by debris and are difficult to clean, and to provide a fish path structure, construction and design method.

[0005] A fishway structure comprises a migratory channel, wherein a plurality of rows of pile structures are arranged at the bottom of the migratory channel, wherein at least two pile structures are arranged at intervals in each row, and the pile structures in adjacent rows are staggered with each other along the length direction of the migratory channel.

[0006] The fishway structure described in the present application provides climbing assistance for eels by arranging pile structures at the bottom of the migratory channel and staggering adjacent rows of pile structures along the length direction of the migratory channel. At the same time, compared with the bristle base, the pile structure does not have bristles, so there is no debris clogging, and it is easy to clean. At the same time, the pile structure can increase friction along the way, water flow counteraction and diffusion to dissipate energy, play the effect of improving the flow state and reducing the flow rate of the migratory channel.

[0007] Preferably, the bottom diameter of the pile structure is larger than the top diameter of the pile structure. On the one hand, the pile structure that is small at the top and large at the bottom is easy to clean. More importantly, such a design will slightly increase the complexity of the local water flow, which is more conducive to the climbing of eels.

[0008] Preferably, the pile structure comprises a plurality of forwardly arranged frustum piles, the lower portion of the frustum piles being connected to the bottom of the migratory channel, the top of the frustum piles being closed, and the height of the frustum piles being greater than the bottom diameter of the frustum piles.

[0009] Preferably, the pile structure is a tubular structure, the lower part of the tubular structure is connected to the bottom of the migratory channel, the upper part of the tubular structure is open, and a through hole is provided on the upstream side of the tubular structure; the upper edge of the tubular structure and the edge of the through hole are in an arc transition; the height of the tubular structure is greater than the bottom diameter of the tubular structure, and the top diameter of the tubular structure is smaller than the bottom diameter of the tubular structure. The inner wall of the tubular structure can also assist eels in climbing, and a through hole is provided on the upstream side of the tubular structure, which can provide better migratory conditions for small fish such as Hepu mitten crabs and eels.

[0010] Preferably, the migratory channel includes a driving mechanism, a four-bar linkage, a base and a slot structure, the base is tilted, the pile structure is arranged at the bottom of the slot structure, and the driving mechanism drives the four-bar linkage to drive the slot structure to slide back and forth with the base. The water flow in the canal or the waves formed by the ship are simulated to get close to the migratory environment of the eels. Moreover, the driving mechanism drives the four-bar linkage to drive the slot structure to slide back and forth with the base, and the eels are better assisted in migrating through the state of rapid advance and slow retreat.

[0011] Preferably, it comprises an eel way and a vertical slot fishway, the migratory fish in the eel way include eels and mitten crabs, the migratory fish in the vertical slot fishway include red-eye trout and dace, the eel way and the vertical slot fishway are located on the same side of the canal, one end of the eel way is connected to the middle of the vertical slot fishway, and the other end extends to the bottom of the canal, and the parts of the eel way and the vertical slot fishway located upstream of the eel way form the migratory channel.

[0012] Preferably, a portion of the vertical slot fishway located upstream of the eel way is provided with water retaining structures at intervals, and a pool chamber is formed between adjacent water retaining structures, the water retaining structure comprises a partition and a guide plate arranged opposite to each other, the guide plate is smaller in width than the partition, and a vertical slot for fish to pass through is provided between the partition and the guide plate, and a plurality of rows of the pile structures are also provided in the pool chamber, wherein each row is provided with at least two pile structures at intervals, and adjacent rows of the pile structures are staggered with each other along the length direction of the migratory channel.

[0013] The present application also discloses a design method for the fishway structure, comprising the following steps:

[0014] S1. Determine the design flow rate of the eel way and the design flow rate of the vertical slot fishway based on the migratory ecological characteristics of the fish passage objects and the initial technical parameters of the fishway. The design flow rate of the vertical slot fishway includes the flow rate through the fish holes / slots, the inlet fish attracting flow rate, the outlet flow rate and the main structure flow rate of the vertical slot fishway.

[0015] S2. Determine the layout of the vertical slot fishway and the eel way, and the location where the eel way connects to the vertical slot fishway based on the initial technical parameters of the fishway, the design flow velocity of the eel way, the design flow velocity of the vertical slot fishway and the tailwater position of the power station in the hub;

[0016] S3: The design water level at the exit of the vertical slot fishway is determined based on the layout of the vertical slot fishway and the eel pass, the design water storage level of the hub and the water level fluctuation parameters; and the design water level at the entrance of the vertical slot fishway is determined based on the average low tide level of the tidal river section downstream of the hub, the water level fluctuation and the cumulative frequency of low tide below the hub lock;

[0017] S4: Determine the angle parameter between the inlet axis of the vertical slot fishway and the riverbed water flow and the inlet width parameter of the vertical slot fishway based on the design water level at the outlet of the vertical slot fishway and the design water level at the inlet of the vertical slot fishway;

[0018] S5: Determine the width of the vertical slot fishway based on the vertical slot fishway inlet width parameter;

[0019] S6: determining the structural parameters of the vertical slot fishway based on the design water level at the vertical slot fishway outlet, the design water level at the vertical slot fishway inlet, the size of the largest fish passing object in the fish passing specification, and the width of the vertical slot fishway;

[0020] S7: Based on the structural parameters of the vertical slot fishway, the structural position of the eelway and the arrangement parameters of the pile structure are designed to obtain a preliminary design scheme for the fishway structure.

[0021] The design method for fishway structure described in the present application determines the design flow rate of the eel way and the design flow rate of the vertical slot fishway based on the ecological characteristics of the fish migration and the initial technical parameters of the fishway. The design flow rate of the vertical slot fishway includes the flow rate through the fish hole / slot, the inlet fish attracting flow rate, the outlet flow rate and the main structure flow rate of the vertical slot fishway. Then, the layout positions of the vertical slot fishway and the eel way are determined, as well as the position where the eel way is connected to the vertical slot fishway; then, the design water level at the outlet of the vertical slot fishway is determined; and the design water level at the inlet of the vertical slot fishway is determined based on the average low tide level, water level fluctuation and cumulative frequency of low tide under the hub gate of the tidal river section downstream of the hub; then, the angle parameter between the inlet axis of the vertical slot fishway and the riverbed water flow and the inlet width parameter of the vertical slot fishway are determined; then, the width of the vertical slot fishway is determined; then, the structural parameters of the vertical slot fishway are determined; then, a preliminary design scheme for the fishway structure is obtained. Thereby achieving the purpose of merging the eel way used for eel migration and the vertical slot fishway used for other fish migration into one place.

[0022] Preferably, the structural parameters of the vertical slot fishway include the bottom slope of the fishway, the designed flow velocity of the fishway and the total length of the fishway. The relationship between the bottom slope of the fishway I, the designed flow velocity v of the fishway and the total length L of the fishway is specifically as follows:

[0023]

[0024] Where I is the bottom slope of the fishway; n is the number of chambers; v is the design flow velocity of the fishway; g is the acceleration of gravity; is the baffle velocity coefficient; l y is the net length of the pool room; k2 is the net length ratio coefficient; k1 is the number ratio coefficient; L is the total length of the fishway

[0025] Preferably, the vertical slot fishway and the eel way are both arranged on the tailwater side of the hub.

[0026] The present application also discloses a construction method, comprising the following steps:

[0027] A1: Design the structural parameters and position parameters required for the fishway using the design method described in this application;

[0028] A2: Select a location and construct the fishway structure using the structural parameters and location parameters of the fishway.

[0029] The invention provides a construction method for a fishway structure, which fully considers the coordinated migration of eels and other fishes, and the design method can provide assistance for the construction. The whole process is scientific, systematic, efficient and of good quality.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The fishway structure described in the present application provides climbing assistance for eels by arranging pile structures at the bottom of the migratory channel and staggering adjacent rows of pile structures along the length direction of the migratory channel. At the same time, compared with the bristle base, the pile structure does not have bristles, so there is no debris clogging, and it is easy to clean. At the same time, the pile structure can increase friction along the way, water flow counteraction and diffusion to dissipate energy, play the effect of improving the flow state and reducing the flow rate of the migratory channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the pile structure arrangement of this application in a raised style.

[0033] Figure 2 This is a schematic diagram of the pile structure layout and pipe structure of this application.

[0034] Figure 3 This is a schematic diagram of the overall layout of the fishway in this application.

[0035] Figure 4 This is a schematic diagram of the vertical seam pool chamber structure of this application.

[0036] Figure 5 This is a schematic elevation diagram of the Eel Road for this application.

[0037] Figure 6 For this application, the Eel Road floor plan.

[0038] Figure 7 Schematic diagram of the location of the eel way and vertical slot fishway for this application.

[0039] Figure 8 This is a schematic diagram of the three-dimensional layout of the pool room for this application. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below in conjunction with specific embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0041] In the description of the specific embodiments of the present invention, unless otherwise specified, the terms indicating the orientation or positional relationship such as "up", "down", "left", "right", "center", "inside", "outside", etc. are all expressions based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship of the invented product / equipment / device when it is usually used. These terms of orientation or positional relationship are only for the convenience of describing the scheme of the present invention or simplifying the description in the specific embodiments, so that the technicians can quickly understand the scheme, rather than indicating or implying that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship, and therefore cannot be understood as a limitation of the present invention. In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding device / component / element is absolutely horizontal or vertical or overhanging or parallel, but can be slightly tilted or have deviations. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted. Alternatively, it can be simplified to understand that the corresponding device / component / element is set in the direction of "horizontal", "vertical", "overhanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, and more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the scheme of the present invention. In addition, the expressions "first", "second", "third", etc. in the terms are only used to distinguish the description of the same or similar parts, and should not be understood as emphasizing or implying the relative importance of specific parts. In addition, in the description of the embodiments of the present invention, "several", "multiple", "several" represent at least 2. It can be any situation of 2, 3, 4, 5, 6, 7, 8, 9, etc., and can even be more than 9. In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / restricted, the terms "set", "install", "connect", "connected", "provided with", "laid", and "arranged" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, and can be welding, riveting, bolting, threading, and other commonly used connection means in the field. This connection can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements.

[0042] Example 1

[0043] like Figure 1-Figure 8As shown, a fishway structure described in this embodiment includes a migratory channel 20, and a plurality of rows of pile structures 22 are arranged at the bottom of the migratory channel 20, wherein at least two pile structures 22 are arranged at intervals in each row, and the pile structures 22 in adjacent rows are staggered with each other along the length direction of the migratory channel 20.

[0044] The fishway structure described in the present application provides climbing assistance for eels by arranging pile structures 22 at the bottom of the migratory channel 20 and staggering adjacent rows of the pile structures 22 along the length direction of the migratory channel 20. At the same time, compared with the bristle base, the pile structures 22 do not have bristles, so there is no debris clogging, and it is easy to clean. At the same time, the pile structures 22 can increase friction along the way, water flow counteraction and diffusion to dissipate energy, play an effect of improving the flow state and reducing the flow rate of the migratory channel 20.

[0045] In a preferred embodiment, the bottom diameter of the pile structure 22 is larger than the top diameter of the pile structure 22. On the one hand, the pile structure 22 that is small at the top and large at the bottom is easy to clean. More importantly, such a design will slightly increase the complexity of the local water flow, which is more conducive to the climbing of eels.

[0046] In a preferred manner, the pile structure 22 includes a plurality of forwardly arranged frustum piles, the lower portion of the frustum piles is connected to the bottom of the migratory channel 20, the top of the frustum piles is closed, and the height of the frustum piles is greater than the bottom diameter of the frustum piles.

[0047] In a preferred embodiment, the pile structure 22 is a tubular structure, the lower part of the tubular structure is connected to the bottom of the migratory channel 20, the upper part of the tubular structure is open, and a through hole 21 is provided on the upstream side of the tubular structure; the upper edge of the tubular structure and the edge of the through hole 21 are in an arc transition; the height of the tubular structure is greater than the bottom diameter of the tubular structure, and the top diameter of the tubular structure is smaller than the bottom diameter of the tubular structure. The inner wall of the tubular structure can also assist eels in climbing, and the through hole 21 is provided on the upstream side of the tubular structure, which can provide better migratory conditions for small fish such as Hepu mitten crabs and eels.

[0048] In a preferred embodiment, the migratory channel 20 includes a driving mechanism, a four-bar linkage, a base and a slot structure, the base is tilted, the pile structure is arranged at the bottom of the slot structure, and the driving mechanism drives the four-bar linkage to drive the slot structure to slide back and forth with the base. The water flow in the canal or the waves formed by the ship are simulated to get close to the migratory environment of the eels. Moreover, the driving mechanism drives the four-bar linkage to drive the slot structure to slide back and forth with the base, and the eels are better assisted in migrating through the state of rapid advance and slow retreat.

[0049] A preferred embodiment includes an eel way 24 and a vertical slot fishway 23, wherein the migratory fish in the eel way 24 include eels and mitten crabs, and the migratory fish in the vertical slot fishway 23 include red-eyed trout and dace. The eel way 24 and the vertical slot fishway 23 are located on the same side of the canal, one end of the eel way 2 is connected to the middle of the vertical slot fishway 23, and the other end extends to the bottom of the canal, and the eel way 24 and the vertical slot fishway 23 located upstream of the eel way 24 form the migratory channel 20.

[0050] In a preferred manner, a portion of the vertical slot fishway 23 located upstream of the eel way 2 is provided with water retaining structures at intervals, and a pool chamber 30 is formed between adjacent water retaining structures. The water retaining structure includes a partition 32 and a guide plate 35 that are relatively arranged, and the guide plate 35 is smaller in width than the partition 32. A vertical slot 31 for fish to pass through is provided between the partition 32 and the guide plate 35. Several rows of the pile structures 22 are also provided in the pool chamber 30, wherein each row is provided with at least two pile structures 22 at intervals, and adjacent rows of the pile structures 22 are staggered with each other along the length direction of the migratory channel.

[0051] Example 2

[0052] like Figure 1-Figure 8 As shown, the design method for the fishway structure described in Example 1 described in this embodiment includes the following steps:

[0053] S1. Determine the design flow rate of the eel way 24 and the design flow rate of the vertical slot fishway 23 based on the migratory ecological characteristics of the fish passage objects and the initial technical parameters of the fishway. The design flow rate of the vertical slot fishway 23 includes the flow rate through the fish holes / slots, the inlet fish attracting flow rate, the outlet flow rate and the main structure flow rate of the vertical slot fishway 23.

[0054] S2. Determine the layout positions of the vertical slot fishway 23 and the eel way 24, and the position where the eel way 24 connects to the vertical slot fishway 23 based on the initial technical parameters of the fishway, the design flow rate of the eel way 24, the design flow rate of the vertical slot fishway 23, and the tailwater position of the power station 27 in the hub 1;

[0055] S3: Determine the design water level at the vertical slot fishway outlet 25 based on the layout positions of the vertical slot fishway 23 and the eel way 24, the design water storage level of the hub 1 and the water level fluctuation parameters; and determine the design water level at the vertical slot fishway inlet 26 based on the average low tide level of the tidal river section downstream of the hub 1, the water level fluctuation and the cumulative frequency of low tides below the hub 1 lock;

[0056] S4: determining an angle parameter between the axis of the vertical slot fishway inlet 26 and the riverbed water flow and a width parameter of the vertical slot fishway inlet 26 based on a design water level at the vertical slot fishway outlet 25 and a design water level at the vertical slot fishway inlet 26;

[0057] S5: Determine the width of the vertical slot fishway 23 based on the width parameter of the vertical slot fishway inlet 26;

[0058] S6: determining the structural parameters of the vertical slot fishway 23 based on the design water level at the vertical slot fishway outlet 25, the design water level at the vertical slot fishway inlet 26, the size of the largest fish passing object in the fish passing specification, and the width of the vertical slot fishway 23;

[0059] S7: Based on the structural parameters of the vertical slot fishway 23, the structural position of the eelway and the arrangement parameters of the pile structure 22 are designed to obtain a preliminary design scheme of the fishway structure.

[0060] A design method for a fishway structure described in the present application determines the design flow rate of the eel way 24 and the design flow rate of the vertical slot fishway 23 based on the migratory ecological characteristics of the fish passing objects and the initial technical parameters of the fishway. The design flow rate of the vertical slot fishway 23 includes the flow rate through the fish holes / slots, the inlet fish attracting flow rate, the outlet flow rate and the main structure flow rate of the vertical slot fishway 23. Then determine the layout positions of the vertical slot fishway 23 and the eel way 24, as well as the position where the eel way 24 is connected to the vertical slot fishway 23; then determine the design water level at the vertical slot fishway outlet 25; and determine the design water level at the vertical slot fishway inlet 26 based on the average low tide level, water level fluctuation and cumulative frequency of low tide under the hub 1 lock in the downstream tidal river section; then determine the angle parameters between the axis of the vertical slot fishway inlet 26 and the riverbed water flow and the width parameters of the vertical slot fishway inlet 26; then determine the width of the vertical slot fishway 23; then determine the structural parameters of the vertical slot fishway 23; and then obtain the preliminary design scheme of the fishway structure. Thus, the purpose of merging the eel way 24 for eel migration and the vertical slot fishway 23 for other fish migration into one place is achieved.

[0061] Preferably, the structural parameters of the vertical slot fishway 23 include the bottom slope of the fishway, the designed flow velocity of the fishway and the total length of the fishway. The relationship between the bottom slope of the fishway I, the designed flow velocity v of the fishway and the total length of the fishway L is specifically as follows:

[0062] Where I is the bottom slope of the fishway; n is the number of chambers 30; v is the design flow velocity of the fishway; g is the acceleration of gravity; is the velocity coefficient of the partition 32; l y is the net length of the pool chamber 30; k2 is the net length proportional coefficient; k1 is the number proportional coefficient; L is the total length of the fishway. Preferably, the vertical slot fishway 23 and the eel way 24 are both arranged on the tailwater side of the hub 1.

[0063] Based on the characteristics of eels, Hepu mitten crabs, red-eyed trout, dace, etc., fishway 2 adopts a double fishway design, and eels and Hepu mitten crabs use a special eel way 24. For red-eyed trout, dace, etc., vertical slit fishway 23 is used.

[0064] Design flow rate of fishway: The design principle of flow rate of fishway is that the flow rate in fishway is less than the cruising speed of fish, so that fish can keep moving forward in fishway; the flow rate of hole or vertical slit 31 in fishway 2 is less than the burst speed of fish, so that fish can pass through. The minimum preferred cruising swimming speed of river perch is 55.83cm / s, and the maximum is 102.12cm / s; the maximum swimming speed of an adult eel with a length of 0.60m is 1.14m / s, and the rushing speed of young eels with a length of 6-9cm varies from 0.60 to 0.90m / s. According to the measured results, the preferred flow rate of eels with a body length of 5 to 10cm is 0.18 to 0.25m / s, and the limit flow rate is 0.45 to 0.50m / s. The design of flow rate of fishway mainly includes the flow rate of fish passage orifice, the fish attracting flow rate at the fishway inlet, and the minimum induced flow rate in the fishway. Based on the above, the design flow velocity of the eel fishway is temporarily set at 0.2m / s, and the design flow velocity of the fishway for red-eyed trout and other fish is temporarily set at 1m / s.

[0065] Fishway inlet design: The key lies in whether fish can be lured from the uncontrolled natural river environment to the controlled fishway. If fish cannot be lured to the fishway, the upstream migration of fish cannot be achieved. The migration routes and clustering areas of migratory fish generally follow the following rules: During the upstream process, when the flow rate of the migration route where the fish are located is too high and they cannot continue to move forward against the current, they will choose to swim upstream in the waters with relatively slow flow rates in the nearby side streams, mostly in the suitable flow rate areas on both sides of the mainstream of the river, or along the shoreline of the river bank; during migration, fish will avoid turbulence, water jumps and whirlpools; during migration, fish will avoid oily and polluted waters, and choose areas with better water quality; young fish generally have the habit of choosing to move towards the sun, shelter from the wind and along the coast. According to the law of fish migration below the dam, the fishway inlet is selected in: places where water often flows down, close to both sides of the mainstream; the velocity barrier or upward limit at the upstream where fish can go upstream downstream of the dam and on both sides; areas with stable and straight water flow and good water quality; the bank slopes on both sides of the downstream of the dam; places that can adapt to the fluctuation of the downstream water level and ensure that the water depth of the fish entrance is more than 1.0m during the fish season. The shape of the inlet pool, the location of the auxiliary water flow diffusion device and the setting of the fish ladder inlet should form a hydraulic environment with a stable water flow form and fish conveying flow rate, so as to guide fish from the fishway inlet to the fish ladder. If there are potential influencing factors such as vortex, water flow dispersion or dead water, the redundant space of the inlet pool and fish conveying trough should be reduced as much as possible. Corners should be designed as circular or similar shapes. At the same time, the area of ​​the fish detention area should be reduced. The fishway should be arranged behind the dam wall on the right bank of the spillway in combination with the terrain conditions around the hub 1 and the overall layout plan of the hub.

[0066] Fishway exit design: The location of the fishway exit has the following requirements: it can adapt to the changes in the upstream water level. In the fishing season, when the water level on the dam changes, it can ensure that the channel exit has sufficient water depth and is well connected with the water surface of the reservoir; the exit should be close to the shore, the water flow outside the exit should be smooth, the flow direction should be clear, there should be no whirlpools, and the fish can smoothly go upstream along the water flow and the shoreline; the exit should be away from areas with polluted water quality and areas that interfere with and intimidate fish; the requirements of upstream fish going downstream should also be considered, and the exit should face the direction of the water flow to facilitate fish to enter the simulated natural channel; the fishway exit should be arranged at a certain distance from the power station 27. If the distance is too close, the fish that have successfully gone upstream will easily be drawn into the turbine by the power discharge water and carried under the dam with the water flow; if the distance is too far, the fish cannot feel the water flow and are easy to lose their way. The exit must adapt to the changes in the upstream water level to ensure that the bottom of the exit cannot be exposed under any water level changes, and there must be a certain water depth, and the bottom plate of the fishway exit must be smoothly connected with the riverbed. The fishway exit is controlled by a gate and connected to the upstream river. A preferred embodiment: the outlet of the fishway 2 is located in the reservoir area upstream of the sluice gate, and the outlet elevation is 17m.

[0067] Design observation room 34: An observation room 34 is set up in the fishway at hub 1, and the observation window is set in the middle and upper part of the fishway, which is used to count the species and number of fish that have successfully gone upstream and evaluate the fish passing effect of the fishway, so as to improve the fishway structure and improve the fish passing effect in the future. Due to the water level changes inside and outside the fishway 2, it is necessary to control the water consumption and operating water level of the fishway 2 to keep the flow velocity and flow state in the channel stable and meet the requirements of fish upstream.

[0068] The ecological water consumption of hub 1 in the dry season is 6.36m3 / s, and that in the flood season is 16.74m3 / s. The water consumption of the fishway in hub 1 is 0.8m3 / s.

[0069] Fishway layout: Eelway 24 is arranged on the right bank of the spillway and connected to the dam wall. The inlet is located about 100m downstream of the spillway, with an inlet elevation of -7.5m, and the outlet is located in the reservoir area upstream of the spillway, with an outlet elevation of 17m. The fishway pipe groove width is 0.5m, the bottom slope is 16%, and the total length is about 150m. The vertical slit fishway 23 is arranged on the left side of the power station 27. In order to meet the needs of fish migration at high and low water levels, the fishway adopts a double inlet form, with inlet elevations of 0.34m and -2.02m respectively, and the fishway outlet elevation is 6.5m. The length of the high water level fishway is 320m, the length of the low water level fishway is 430m, and the fishway width is 3m.

[0070] The water level of the fishway upstream and downstream directly affects whether the fishway has suitable conditions for fish passing during the fishing season; the water level fluctuations upstream and downstream of the fishway will also affect the water surface connection between the fishway outlet and the inlet and the water flow conditions of the pool chamber 30, making it impossible for fish to enter the reservoir, and also making it impossible for fish near the downstream inlet to enter the fishway. The normal water storage design water level of the fishway outlet during the fishing season of this hub is 8.7m, the design high water level of the fishway inlet is the average high tide level of the estuary of 1.84m, the design low water level of the fishway inlet is the average low tide level of the estuary of -0.52m, and the maximum design water level difference is 9.22m.

[0071] Structure of eel way 24: According to the migratory characteristics of eels [young eels] and Hepu mitten crabs [young crabs], the structure of the fishway selects a PVC pipe trough, and a pile structure 22 is set at the bottom to provide them with good climbing space and climbing support. The friction resistance along the way brought by the pile structure 22, water flow concussion and diffusion are used to dissipate energy, thereby improving the flow state and reducing the flow velocity of the vertical seam 31 passing through the fish.

[0072] Structure of vertical slot fishway 23: The water level difference at the downstream estuary of vertical slot fishway 23 is large, and vertical slot fishway 23 is provided with two high and low inlets and one outlet. The preliminary design scheme is: the total length of vertical slot fishway 23 is 431m, and the slope is 2.58%. The width of vertical slot fishway 23 is 3m. Each pool chamber 30 is 2.2m long and the designed water depth is 1.5m. Rest pool 36 is set every 10 to 20 pool chambers 30, the outlet elevation of vertical slot fishway 23 is 6.5m, the low inlet elevation of vertical slot fishway 23 is -2.02m, and the high inlet elevation is 0.34m. A gate is set at the outlet of vertical slot fishway 23 to prevent flooding and inspect vertical slot fishway 23. The side wall is 3.8m high, with a water retaining baffle 32 and a guide plate 35, both 2.7m high, and a 0.2m wide vertical seam 31 between the baffle 32 and the guide plate 35; the water depth in the pool is 1.0m, and the maximum flow rate is about 1m / s. The scale parameters and reasons of the fishway are detailed in Table 1

[0073] Table 1: Fishway scale table

[0074]

[0075] In the above table, the width of the fishway is mainly determined by the amount of fish passing through and the size of the individual fish passing through. The larger the amount of fish passing through and the larger the individual fish passing through, the wider the fishway should be. The net width of the pool chamber 30 should not be less than twice the body length of the main fish passing through. The water depth of the fishway is mainly determined by the habits of the fish passing through. Bottom fish and larger adult fish require deeper water depth accordingly. The water depth of the fishway is generally 1m to 3m.

[0076] Width of vertical slit 31 of vertical slit fishway 23: The width b of vertical slit 31 in the pool 30 is directly related to the energy dissipation effect of the fishway and the passability of fish. It is generally required that the width b of vertical slit 31 should not be less than 1 / 2 of the body length of the fish object. In the fishway database, the width of vertical slit 31 of vertical slit fishways on the same side in foreign countries is generally 1 / 8 to 1 / 10 of the width of the pool 30, while the width of vertical slit 31 on the same side in my country is generally 1 / 5 of the width of the pool 30 and 1 / 5 to 1 / 6 of the length of the pool 30. Therefore, the width of vertical slit 31 is 30 cm.

[0077] Observation Room 34: Mainly used to observe the migration of fish and related data, providing a basis for future research on the migration patterns and living habits of fish and the construction of fishways.

[0078] Confirm the purpose of fish passage at Hub 1: The downstream of Hub 1 is a tidal river section. After the completion of the canal, the downstream was deepened due to the requirements of the waterway, which will intensify the upstream movement of salt water, resulting in an increase in the salinity of the downstream habitat. The number of estuarine fish species that migrate upstream to the lock may increase simultaneously. At the same time, these fish have the need to migrate between seawater and freshwater at different stages of their life history. The construction of the fishway at Hub 1 provides them with upstream and downstream channels. Therefore, the main purpose of fish passage at Hub 1 is to connect the migratory channels of river-sea migratory fish, provide upstream conditions for estuarine fish, and provide migratory channels and gene exchange channels for freshwater fish.

[0079] Based on the interaction between freshwater runoff and seawater intrusion, estuarine fish communities are classified into six ecological groups: a. Estuarine resident fish [ES]: The entire life cycle takes place in estuarine waters; b. Marine occasional fish [MS]: Live in the ocean for most of their life and occasionally come to estuarine waters for feeding; c. Downstream migratory fish [CA]: Mainly live in freshwater rivers and visit rivers; The estuary is an important migratory channel for them to lay eggs in the ocean; d. Anadromous fish [AN]: Unlike catadromous fish, they lay eggs in freshwater rivers, but raise their young and forage in estuarine waters, and adult fish mostly live in the ocean; e. Marine migratory fish [MM]: They live in near-shore waters for part of their life history, but estuarine waters are important places for foraging and raising their young, and are also important habitats for adult and juvenile fish; f. Freshwater fish [FW]: All stages of their life history are spent in the freshwater environment of the estuary's adjacent river area.

[0080] The fish species migratory in estuaries, rivers and seas include eels, flower eels, and spotted sea bass, while the fish species migratory upstream include seven-thread anchovy and flower mullet, etc.

[0081] There are three species of river-sea migratory fish in the canal, namely, eel, flower eel, and seven-thread anchovy; there are eight species of estuarine fish, namely, flower shad, spotted shad, spotted perch, Chinese black snakehead, spotted tongue goby, silverfish, tongue goby, and half-ribbed Chinese fish, which are distributed in the downstream section of Hub 1. The canal has an estuary, which is a channel for long-distance migration of eels and other fish.

[0082] After the construction of Hub 1, the downstream will be a tidal river section, and the water flow habitat will undergo certain changes. Therefore, the main fish passing through the fishway at Hub 1 are downstream migratory fish [CA], upstream migratory fish [AN], and freshwater fish with historical distribution.

[0083] Therefore, after the review, the main fish species that can be fished are: downstream migratory fish [CA] flower eel, eel, and flower perch; upstream migratory fish [AN] seven-thread anchovy and flower bream; historically distributed freshwater fish red-eye trout and dace; and the other fish species that can be fished are: spotted bream, Chinese black mullet, spotted tongue goby, Ju's silverfish, tongue goby, semi-ridged Chinese [fish mang] and other estuarine fish, and Hepu mitten crab. The main fish species that can be fished are seven-thread anchovy, flower bream and other fish that can be fished in the sea and river as the main fish species, and Chinese black mullet, spotted tongue goby and other estuarine fish as the secondary fish species.

[0084] The time period for fish passage in the hub 1 fishway was confirmed based on the fish passage season: the fish passage season is from February to November. The fish passage time was confirmed based on the reselection of the fish passage objects and the sorting of their migration seasons. Young eels migrate upstream to the estuary in groups from December to May of the following year and migrate into freshwater rivers. The gonadal development of male and female Coilia septempunctata is basically the same. Parents spawn twice a year. The first spawning period is from February to March. The spawning is completed in April. After that, the parent group moves to the open sea. The individual body length of the young fish found in May has reached 40 to 50 mm. In autumn, the spawning fish gather again at the estuary and spawn for the second time in August to September. Flower bream usually lives in brackish and freshwater areas. Its spawning period is from April to August. During the spawning season, it migrates to the estuary or inland river to spawn. The spawning period of tongue goby is from April to August every year. The passage period for eels and flower eels is from December to May of the following year; the passage period for seven-thread anchovies is from February, March, August and September of each year; the passage period for flower perch is from November to January of the following year; the passage period for flower bream and tongue goby is from April to August of each year; the passage period for red-eyed trout and dace is from April to September of each year. In summary, the passage season for fish in the hub is from November to September of the following year, and it can be stopped in October for dredging and maintenance.

[0085] Fish size: The length of sexually mature individuals of seven-thread anchovies is 100-290mm for females, with the smallest sexually mature individual being 102mm long and weighing 4.5g; the length of males is 90-220mm, with the smallest sexually mature individual being 90mm long and weighing 3g. The common length of flower bream is 40-240mm. The length of a sexually mature 3-year-old flower perch is up to 600mm. The length of young eels that reach the estuary is 100-200mm.

[0086] In summary, the main specification range of fish passing through the vertical slot fishway 23 at the hub 1 is 40 to 600 mm, and the specification of fish passing through the eel channel 24 is 100 to 500 mm.

[0087] Design flow rate of vertical slot fishway 23: Flow rate through fish hole / slot: The boundary condition of the flow rate design of the control section of vertical slot fishway 23 is to ensure that there is a 0.10m low flow rate area near the bottom wall of the fish hole for the middle and bottom fish to pass through, and the flow rate in this area is in the range of 0.29-0.54m / s. The remaining high flow rate area in the middle is mainly for large individual fish to sprint through, and the maximum endurance speed is taken. The flow rate range of the fish hole / slot is 0.54-1.37m / s, and the average flow rate can be about 1.0m / s. Inlet fish attracting flow rate: The preferred flow rate of fish is generally within the continuous speed range of fish, taking 60%-80% of the critical swimming speed. According to the test results, the inlet fish attracting flow rate should not be lower than the fish sensing flow rate of 0.2m / s, preferably 0.35-0.73m / s. Outlet flow rate: The outlet of the vertical slot fishway 23 should maintain a certain flow rate so that the fish will not be affected in their normal migration after swimming out of the vertical slot fishway 23. Therefore, the outlet of the vertical slot fishway 23 cannot be arranged in a completely still water place, so that the fish cannot sense the flow rate and are easily lost. At the same time, the outlet position should not be too close to the discharge structure, and if the flow rate exceeds the critical flow rate of fish, the fish will be easily sucked into the sluice and taken downstream. According to the test results, the flow rate near the fishway outlet should not be still water, and 0.24-0.35m / s is appropriate. Main structure flow rate: The average flow rate of the pool chamber 30 is 0.24-0.67m / s, and try to ensure that there is at least 0.10-0.30m of low flow rate area near the bottom wall for fish to live, and the flow rate in this area is within 0.48m / s.

[0088] Design flow rate of eel channel 24: So far, there is no eel channel 24 specially built for eels in the existing technology. Experiments show that although the swimming ability of young eels is relatively weak, they can still swim upstream easily when the flow rate is lower than 1.8m / s. They are not washed away by the water flow, but swim against the current or hold their position tightly. Eels are fish with climbing habits. Although their swimming ability is measured to be relatively small, they should not be simply designed based on the measured swimming ability. The eel channel 24 can be designed to be a steeper slope, but staggered cylindrical tubes or piers should be designed at the bottom to provide a foothold for their climbing.

[0089] In summary, the main fish species passing through the fishway at Hub 1 should be downstream migratory fish [CA] flower eel, eel, and flower perch; upstream migratory fish [AN] seven-thread anchovy and flower bream; historically distributed freshwater fish red-eye trout and dace. Other fish species that should be considered include: spotted bream, Chinese black mullet, spotted tongue goby, silverfish, tongue goby, semi-ridged Chinese fish [fish mang] and other estuarine fish; and Hepu mitten crab. The fish season of Hub 1 fishway is from November to September of the following year. The size range of the main fish species passing through Hub 1 fishway is 40-600mm. The flow rate through the fish hole / slit ranges from 0.54 to 1.37 m / s, and the average flow rate can be about 1.0 m / s; the average flow rate of the pool chamber 30 is 0.24 to 0.67 m / s; the inlet fish attracting flow rate should not be lower than the fish sensing flow rate of 0.2 m / s, preferably 0.35 to 0.73 m / s; the outlet flow rate should not be still water, preferably 0.24 to 0.35 m / s. Eels are fish with climbing habits. Although the measured swimming ability is small, it should not be simply designed based on the measured swimming ability. The eel path 24 can be designed as a steeper slope, but staggered cylindrical tubes or piers should be designed at the bottom to provide a fulcrum for climbing.

[0090] The fishway scheme is designed based on the ecological characteristics of the fish migration objects and the fishway database at the hub, and the preliminary design scheme of the fishway structure is determined:

[0091] Fishway 2 overall plan: Establish a fishway database at the hub. The existing fishway plans in the fishway database at the hub include the left and right bank double fishway plan, the left bank double fishway plan and the right bank double fishway plan.

[0092] In this application, the preliminary design plan is first proposed as a double fishway plan on the left and right banks: Hub 1 has two fishways: a vertical slit fishway 23 and an eel way 24, and the two fishways are located on the left and right banks respectively. Eel way 24 is arranged on the right bank of the flood discharge gate after connecting to the dam wall. The inlet is located about 100m downstream of the flood discharge gate, with an inlet elevation of -7.5m, and the outlet is located in the reservoir area upstream of the flood discharge gate, with an outlet elevation of 17m. The width of the fishway pipe groove is 0.5m, the bottom slope is 16%, and the total length is about 150m. The vertical slit fishway 23 is arranged on the left side of the power station 27. In order to meet the needs of fish migration at high and low water levels, the fishway adopts a double inlet form, with inlet elevations of 0.34m and -2.02m respectively, the fishway outlet elevation is 6.5m, the length of the high water level fishway is 320m, the length of the low water level fishway is 430m, the fishway slope is 2.85%, and the fishway width is 3m.

[0093] After that, the left and right bank double fishway scheme was reviewed and optimized, and the optimized preliminary design scheme was the left bank double fishway scheme: after review, the vertical slot fishway 23 and the eel way 24 were arranged on the left bank, close to the shore side of the tailwater of the power station 27. The eel way 24 met with the vertical slot fishway 23 near the downstream observation room 34, and then merged into the vertical slot fishway 23.

[0094] Scheme comparison: The vertical slot fishway 23 of the left and right bank double fishway scheme and the left bank double fishway scheme are both arranged on the left bank. The main difference is the location of the eel way 24. The inlet of fishway 2 should be arranged near the mainstream, at the downstream end of the physical obstacle or velocity obstacle that fish can go upstream to. The eel way 24 of the left and right bank double fishway scheme is arranged on the right bank of the sluice, and the opening probability of its adjacent gate holes is not high, so the effect is limited. The left bank double fishway scheme arranges both the eel way 24 and the vertical slot fishway 23 on the tailwater side of the power station 27, which is the mainstream edge of the physical obstacle [sluice] under most working conditions, meeting the conditions of attracting and bringing in fish. In summary, the left bank double fishway scheme is selected as the overall preliminary design of fishway 2.

[0095] Design water level of vertical slot fishway 23: the design water storage level of hub 1 is 8.7m, the dead water level is 8.0m, and the water level fluctuation is 0.7m. Therefore, the design water level of vertical slot fishway outlet 25 is 8.0~8.7m, and the water level fluctuation is 0.7m. The downstream of hub 1 is a tidal river section. The design high water level of the fishway inlet is the average high tide level of 1.84m at the estuary, and the design low water level of vertical slot fishway inlet 26 is the average low tide level of -0.52m at the estuary, and the water level fluctuation is 2.36m. The elevation of the designed inlet bottom plate is lower than the low tide level of -1.31m with a cumulative frequency of 90% of the low tide under the gate, which can ensure that no waterfall is formed at the vertical slot fishway inlet 26.

[0096] like Figure 2 As shown in the figure, the layout principle of the vertical slot fishway inlet 26 is as follows: a. The fish inlet should be arranged at the upstream where fish can go upstream due to the steady and straight water flow, such as the sluice gate, the tailwater of the power station 27, and the ecological water outlet, or near the fish migration route and the place where fish often gather. b. The fish inlet should avoid strong vortexes, backflows, dead water areas and siltation areas. c. The angle between the axis of the fish inlet and the riverbed water flow should not be greater than 45°. According to the above design principles, the vertical slot fishway inlet 26 is arranged on the left bank side of the downstream slope of the tailwater. The angle between the axis of the fish inlet and the riverbed water flow is 45°, and the inlet width is consistent with the fishway width, which is set to 3m. The design low water level is the average low tide level of the estuary -0.52m, the design high water level is the average high tide level of the estuary 1.84m, and the water level difference is 2.36m. The cumulative frequency of low tide below the gate is 90% and the low tide level is -1.31m. Design an inlet with an inlet bottom plate elevation of -1.52m and a wall height of 6m. Ensure that 90% of low tides do not cause waterfalls and that the water is not submerged at high tides. The operating water depth ranges from 1m to 3.36m.

[0097] like Figure 2As shown in the figure, the layout principle of the vertical slot fishway outlet 25 is as follows: a. The fish outlet should be arranged in an area with smooth external water flow and no circulation, so as to facilitate the fish to go upstream; b. The fish outlet should be set in combination with operation management, avoiding floating objects gathering areas, docks, swimming, cruise ships and other areas, and should be far away from various water inlets (intakes) and the entrances of navigation buildings; c. The angle between the fish outlet axis and the riverbed water flow should not be greater than 45°; d. The fish outlet should be open, and facilities such as pollution blocking, floating blocking, pollution cleaning and pollution flushing can be set as needed. e. The fish outlet should be equipped with a gate to meet the operation and maintenance requirements of the fishway. Therefore, the fishway outlet is arranged on the left bank about 150m upstream of the dam. The angle between the outlet axis and the riverbed water flow is set to 30°. The total operating water level of the outlet is 8.0-8.7m, with one outlet and the outlet bottom plate elevation of 7m. The outlet is equipped with a gate, and the gate elevation is set above the flood level to prevent it from being damaged during floods.

[0098] like Figure 3 As shown, the structural parameters of the vertical slit fishway 23 are as follows: Width of the pool chamber 30: The width of the pool chamber 30 should be greater than 2 times the body length of the fish object. When there are multiple types of main fish objects, it should be determined according to the size of the largest fish object. Preferably, the specifications of the main fish objects are 4 to 60 cm, and the width of the fishway is selected to be 3 m, which can meet the requirements of fish passing and is relatively economical. Length of the pool chamber 30: The net length of the pool chamber 30 can be 1.2 to 1.5 times the width of the trough body. Preferably, the length of the pool chamber 30 is 3.6 m. Depth of the pool chamber 30: The water depth of the pool chamber 30 should meet the requirements of the body height of the fish object and the energy dissipation of the pool chamber 30. The minimum water depth should be greater than 2.0 times the body height of the largest fish object, and not less than 1.0 m. Preferably, the design water depth h is 1.0 to 3.36 m. Width of the vertical slit 31 of the fishway: The width of the vertical slit 31 of the partition 32 should not be less than 1 / 3 of the body length of the fish object. A vertical slit 31 type partition 32 is selected. Preferably, the width B of the vertical slit 31 is 0.45 m. The calculation model of the structural parameters of the vertical slit fishway 23 is as follows: I=Δh / (l y +d); n = H / Δh-1; L = n (l y +d)+m(Δl+d); Q=Bhv. In the formula, h is the allowable water level difference of the partition 32; v is the design flow velocity of the fishway; g is the acceleration of gravity; is the velocity coefficient of the partition 32, which is determined through hydraulic model tests and comprehensive analysis; I is the slope of the bottom slope of the fishway; h is the water level difference of the partition 32; ly is the net length of the pool 30; d is the thickness of the partition 32; n is the number of pools 30; H is the elevation difference of the bottom plate of the vertical seam fishway inlet and outlet; m is the number of rest pools 36; that is, m=k1n, k1 is the quantity ratio coefficient; l=k2l y , k2 is the net length ratio coefficient; L is the total length of the fishway; l is the net length of the rest pool 36; Q is the flow rate of the fishway, B is the width of the vertical slit 31; h is the water depth,

[0099] A preferred method: v is 1.0m / s; it can be 0.85-1.00, or determined through hydraulic model test and comprehensive analysis. Because the pile structure 22 is set at the bottom, it is 0.85. The water head difference of the partition 32 calculated in this way is about 0.0706m; the water level difference of the partition 32 is 0.0706m, the thickness of the pool chamber 30+partition 32 is 3.6, and the bottom slope I=0.0196=1:51.02; H is 8.52m; h=0.0706m. n=120, a rest pool 36 is set every 15-30 pool chambers 30, and k1 is 1 / 15-1 / 30. The rest pool 36 should be flat-bottomed, and the length of the rest pool 36 should not be less than twice the length of the pool chamber 30, and k2≥2. When the rest pool 36 is arranged at a turning point, the length should be appropriately lengthened. There are three rest pools 36 in the fishway at the hub, each of which is 6.6m long. L is the total length of the fishway; m is 3; l is 6.4; after calculation: L = 452m. Q is the flow rate of the fishway, which is 0.45-1.5m 3 / s.

[0100] Fishway bottom plate structure: Eels can swim upstream through the dam through the vertical slit fishway 23. According to the preliminary design of the fishway structure, the eelway 24 and the vertical slit fishway 23 meet near the observation room 34, and then merge into the vertical slit fishway 23 to form a merged section. Therefore, the part of the vertical slit fishway 23 located in the merged section needs to have the function of providing a migratory channel for eels. In order to adapt to the climbing habits of eels, a pile structure 22 is set at the bottom of the vertical slit fishway 23. The pile structure 22 is set to be cylindrical, with a diameter of 15 cm and a height of 10 cm. The center line distance between the two cylindrical piles is 45 cm, and the two rows are staggered. The pile structure 22 can be in the form of inlaid PVC pipes.

[0101] Inlet water replenishment: During the operation of the fishway, the upstream water level may be low and the downstream water level may be high. In extreme cases, the downstream inlet may have a very small flow rate due to the high water level, or even less than the induced flow rate of fish. In this case, the inlet needs to be replenished with water.

[0102] When the water depth at the inlet and outlet of the fishway at hub 1 is the same, the flow velocity of the vertical seam 31 is 1m / s. However, under specific working conditions, that is, the water depth at the fishway outlet is 1m and the water depth at the inlet is 3.36m, the flow velocity at the inlet is about 0.04m / s, and the flow velocity at the first vertical seam 31 after the inlet is 0.30m / s. Therefore, water replenishment is mainly carried out at the inlet. After water replenishment, the inlet flow velocity should be greater than 0.2m / s, corresponding to a water replenishment flow rate of 1.5m 3 / s, at this time the fishway flow rate is 0.45m 3 / s. The water replenishment flow rate during the specific operation process is adjusted according to the actual inlet flow rate monitoring to ensure that the inlet flow rate is greater than 0.2m / s. Therefore, the maximum flow rate of the fishway + water replenishment operation is 1.95m 3 / s. The inlet water supply adopts side wall dispersed water supply, and the outlet is intercepted by mesh to prevent fish from mistakenly entering the water supply pipe.

[0103] Table 2 Fishway parameters

[0104] project parameter project parameter project parameter project parameter Fish pass type Vertical slot fishway 23 Pool room 30 length 3.6m Fishway slope 1：51.02 Rest pool 36 quantity 4 Fishway flow control 1.0m / s Pool room 30 width 3m Import quantity 1 Rest pool 36 length 6.6m Fishway operation flow <![CDATA[0.45-1.5m 3 / s]]> Vertical seam 31 width 0.45m Import elevation -1.52m Export quantity 1 Fishway + water replenishment flow <![CDATA[0.45-1.95m 3 / s]]> Pool Room 30 quantity 120 Fishway Chief 458m Exit elevation 7m

[0105] Design of Eel Passage 24: Fishway 2 includes a vertical slot fishway 23 and an eel pass 24. The bottom plate elevation of the vertical slot fishway inlet 26 is -1.52m, but the riverbed below the lock is excavated to an elevation of -7.5m. In this regard, the vertical slot fishway inlet 26 is mainly located in the surface waters. In order to fully attract fish from all water layers, especially climbing fish, it is very necessary to set up an eel pass 24. The eel pass 24 in the fishway database at the hub usually includes an inclined channel with an inclination of preferably 5°-45°, equipped with a base for easy climbing.

[0106] There are some application cases of eel-specific bristle bases, and they have been proven to be effective, but the bristles are easily clogged by debris and are not effective at high flow rates. When there is a large water level fluctuation in the downstream of the canal, the bristle base is considered to be less effective at high flow rates, and is easily clogged and difficult to clean. The innovative improvement of this application uses a pile structure 22 to embed the matrix.

[0107] like Figure 4 As shown, the inlet of the eel channel 24 is set as a vertical pipe, installed at the intersection of the vertical retaining wall on the left bank and the downstream bank, and facing the bank, with 7 vertical openings climbing along the bank, as 7 eel inlets 33. Starting from the riverbed bottom plate at -7.5m, an eel inlet 33 is set every 1m. Figure 5 and Figure 6 As shown, the main channel is an aluminum water tank with a length of 13m, a width of 0.27m, and a height of 0.1m, and the water tank has a slope of 15°. The water tank is covered with a lid to provide a dark environment for migrating eels. A plastic climbing matrix 20 is placed in the water tank, which is composed of staggered plastic pipes. The water tank pipes can be immersed in a water flow greater than 3cm deep, which can not only keep the eels moist, but also encourage them to climb the steep slope. The eel way 24 merges into the vertical slit fishway 23 at the third rest pool 36 downstream, and then the eels will continue to swim upstream using the vertical slit fishway 23. Observation room 34: The fishway 2 is provided with an observation room 34, which is located on the upstream side of the intersection of the vertical slit fishway 23 and the eel way 24, to count the species and number of fish that have successfully gone upstream, and evaluate the fish passage effect of the fishway, so as to improve the structure of the fishway in the future and improve the fish passage effect.

[0108] In summary: a. According to the water dispatching plan for the fishway at hub 1, considering that the operation of power station 27 has more constant water flow than the sluice and is less likely to produce a backflow zone induced by the sluice dispatching, after review at this stage, the vertical slot fishway 23 and the eel way 24 are arranged on the left bank, close to the shore side of the tailwater of power station 27. The eel way 24 meets the vertical slot fishway 23 near the downstream observation room 34, and then merges into the vertical slot fishway 23. b. The bottom slope of the vertical slot fishway 23 is 1:51.02, with a total length of 458m, and is set with 1 inlet, bottom elevation -1.52m, and 1 outlet, bottom elevation 7m. The fishway comprises 30120 pool chambers and 364 rest pools. The cross section of the pool chamber 30 is a rectangular cross section, the bottom slope of the pool chamber 30 is I=1.96%, the thickness of the partition 32 and the guide plate 35 are both 30 cm, the diversion angle is 30°, no pier heads are set at the ends of the partition 32 and the guide plate 35, and the ends are rounded with a radius R=15 cm; the net width of the pool chamber 30 is 3.0 m, the length of the pool chamber 30 is 3.6 m, the designed water depth h is 1.0~3.36 m, the designed vertical seam 31 is 45 cm wide, and a pile structure 22 with a diameter of 15 cm and a height of 10 cm is set at the bottom. The center line spacing of the piles is 45 cm, and they are arranged in two rows in a staggered manner. c. At the intersection of the vertical retaining wall on the left bank and the downstream bank, a vertical eel channel 24 entrance is set toward the bank. Starting from the riverbed bottom plate at -7.5m, an entrance is set every 1m, with a total of 7 eel entrances 33; the main channel is an aluminum water trough with a length of 13m, a width of 0.37m and a height of 0.1m. The slope of the water trough is 15°. The water trough is covered with a cover. A plastic climbing matrix 20 is placed in the water trough. The matrix is ​​composed of staggered plastic pipes. The water trough pipes can be immersed in a water flow greater than 3cm deep; the eel channel 24 merges into the vertical slot fishway 23 at an elevation of 3.39m, and then the eels will use the vertical slot fishway 23 to continue to swim upstream. d. An observation room 34 is provided on the upstream side of the intersection of the vertical slot fishway 23 and the eel way 24 to count the species and quantity of fish that have successfully gone upstream and to evaluate the fish passing effect of the fishway so as to improve the structure of the fishway and the fish passing effect in the future, and also has the function of publicity and demonstration.

[0109] In general, it is used in the following steps:

[0110] 1. Study the swimming ability of target fish species passing through the fishway to clarify the migratory ecological characteristics of the target fish species at the hub.

[0111] The main fish species in the fishway are downstream migratory fishes [CA] flower eel, eel, and flower perch, upstream migratory fishes [AN] seven-thread anchovy, flower mullet, historically distributed freshwater fishes red-eye trout and dace; other fish species that are also considered are spotted mullet, Chinese black mullet, spotted tongue goby, silverfish, tongue goby, half-ribbed Chinese [fish mang] and other estuary-dwelling fish, and Hepu mitten crab. The fish passing season is from November to September of the following year. The main fish species of the vertical slot fishway 23 are 40-600mm, and the fish species of the eel channel 24 are 100-500mm.

[0112] By testing the swimming ability of major fish species such as sea bass, eel, red-eyed trout, and dace, as well as the fish currently distributed in this section of the river, the design indicators of the fishway at the hub were comprehensively determined: the flow velocity range of the fish holes / slits of the vertical slot fishway 23 is 0.54-1.37 m / s, and the average flow velocity can be about 1.0 m / s; the average flow velocity of the pool chamber 30 is 0.24-0.67 m / s; the inlet fish-attracting flow velocity should not be lower than the fish-sensing flow velocity of 0.2 m / s, and should be 0.35-0.73 m / s; the outlet flow velocity should not be still water, and should be 0.24-0.35 m / s; eels are fish with climbing habits, and the eel way 24 should not be simply designed based on the measured swimming ability, but can be designed as a steeper slope, but staggered cylindrical tubes or piers should be designed at the bottom to provide a fulcrum for their climbing.

[0113] 2. Design of fishway 2 scheme, propose a preliminary design scheme of the fishway structure, which includes the preliminary design scheme of the fishway plane and the structural layout of the pool chamber 30.

[0114] The fishway at hub 1 adopts a left bank double fishway scheme, with the vertical slot fishway 23 and the eel way 24 both arranged on the shore close to the tailwater of the power station 27; the eel way 24 meets the vertical slot fishway 23 near the downstream observation room 34, and then merges into the vertical slot fishway 23.

[0115] The design scheme of the vertical slot fishway 23 is: bottom slope 1:51.02, total length 458m, single inlet, bottom elevation -1.52m, single outlet, bottom elevation 7m; the fishway includes 120 pool chambers 30 and 4 rest pools 36. The cross section of the pool chamber 30 is a rectangular cross section, the bottom slope I = 1.96%, the thickness of the partition 32 and the guide plate 35 are both 30cm, the diversion angle is 30°, no pier heads are set at the ends of the partition 32 and the guide plate 35, and they are rounded with a radius R = 15cm; the net width of the pool chamber 30 is 3.0m, the length of the pool chamber 30 is 3.6m, the design water depth h is 1.0~3.36m, the design width of the vertical slot 31 is 45cm, and a pile structure 22 with a diameter of 15cm and a height of 10cm is set at the bottom. The center line spacing of the piles is 45cm, and they are arranged in two rows in a staggered manner.

[0116] The design of Eelway 24 is as follows: at the intersection of the vertical retaining wall on the left bank and the downstream bank, 7 vertical entrances are set toward the bank, vertically upward from the riverbed bottom plate at -7.5m, with an entrance set every 1m; the main channel is an aluminum water trough with a length of 13m, a width of 0.37m and a height of 0.1m. The slope of the water trough is 15°. The water trough is covered with a cover. A plastic climbing matrix 20 is placed in the water trough. The matrix is ​​composed of staggered plastic pipes, and the water depth of the water trough pipes is greater than 3cm; Eelway 24 merges into the vertical slit fishway 23 at an elevation of 3.39m, and then the eels will use the vertical slit fishway 23 to continue upstream.

[0117] 3. Physical model test of local section of fishway project: Based on the preliminary design scheme, a local section model of the fishway with a geometric scale of 1:4 is established, and the structural layout demonstration and optimization research of 23 pools and 30 chambers of the vertical slot fishway are carried out, and a recommended scheme for the structure of pool 30 is proposed.

[0118] The preliminary design of the vertical slot fishway 23 is basically reasonable in terms of the size of the pool chamber 30, the width of the vertical slot 31, and the main bottom slope design, which meet the requirements for the target fish to swim upstream; the fishway flow rate is about 0.50m3 / s, and the velocity coefficient of the partition 32 is φ=0.97; the diversion angle is small, so that the average flow velocity of the vertical slot 31 is 1.11m / s, which exceeds the design requirement. The mainstream in the pool chamber 30 is straight and the efficiency effect is poor. At the same time, the circulation develops unilaterally, which can easily cause small fish to lose their way and delay their upstreaming time.

[0119] In view of the problem that the water flow conditions in the vertical seam 31 and the pool chamber 30 do not meet the upstream requirements of fish due to the small value of the diversion angle, the diversion angle is adjusted and optimized with the optimization idea of ​​promoting the deflection of the mainstream in the pool chamber 30 and increasing the mainstream energy dissipation. After comparing multiple groups of optimization schemes, a recommended scheme for the structure of the pool chamber 30 is proposed, which keeps the scale of the pool chamber 30, the width of the vertical seam 31 and the bottom slope of the pool chamber 30 unchanged, and increases the diversion angle to 45°. Under this scheme, the average water level difference of the pool chamber 30 is 0.07m, the average flow velocity of the vertical seam 31 is 1.01m / s, and the flow velocity of the vertical seam 31 is distributed between 0.99 and 1.06m / s. The flow velocity of the vertical seam 31 meets the design index requirements, and the flow velocity coefficient φ=0.86 corresponds to a design water depth of 1m. The flow rate of the vertical seam 31 is about 0.45m3 / s, which is about 7% lower than the design scheme.

[0120] Fourth, the overall model test of the fishway, based on the recommended scheme of the pool chamber 30 structure and the plane layout design scheme of the vertical slit fishway 23, established a fishway overall model with a geometric scale of 1:15, carried out the overall hydraulic characteristics test of the vertical slit fishway 23, and put forward the overall layout recommendation and operation suggestions of the fishway. According to the design scheme, the flow rate of the fishway is mainly controlled by the water level of the upstream reservoir. Under the working condition of the reservoir water level of 8.7m, the flow rate of the fishway is 0.74m3 / s; under the working condition of the reservoir water level of 8.0m, the flow rate of the fishway is 0.44m3 / s; under each working condition, the water depth of each pool chamber 30 along the way meets the design requirement of not less than 1.0m; when the water level of the reservoir is 8.7m, when the water level below the dam is lower than 0.18m, the vertical seam 31 and pool chamber 3 in the lower section of the fishway (below the 1# rest pool 36) 0 flow rate mostly exceeds the design requirements, the maximum flow rate of vertical seam 31 is 1.66m / s, and the maximum flow rate of pool 30 is 1.31m / s; the flow rate at the fishway inlet gradually decreases with the increase of downstream water level, and the mainstream flow rate at the inlet of working condition 6 is only 0.15m / s, which does not meet the design requirements. The flow rate at the fishway inlet of other working conditions is 0.21-0.69m / s; the water flow at the fishway outlet is smooth, and the flow rate is mostly within 0.03-0.1m / s, which meets the design requirements. In view of the problem of excessive flow rate in the vertical seam 31 and the pool of the lower section of the fishway in the design plan, the overall layout of the fishway is recommended to reduce the bottom elevation of the fishway inlet from -1.52m to -2.22m and increase the slope of the most downstream straight section pool 30 (adjusted from 1.95% to 3.24%). Recommended solution: Under the operating conditions of working conditions 3 and 6, the inlet flow rate is lower than the fish induction flow rate, which makes it difficult to ensure the fish attracting effect at the fishway inlet. Water replenishment is required. The minimum water replenishment flow rates of working conditions 3 and 6 are 0.7m3 / s and 1.0m3 / s respectively. When it is impossible to set up inlet water replenishment measures, it is recommended to set up water flow propellers at the fishway inlet to meet the inlet fish attracting flow rate requirements.

[0121] Example 3

[0122] like Figure 1-8 As shown, a construction method described in this embodiment includes the following steps:

[0123] A1: Design the structural parameters and position parameters required for the fishway using the design method described in Example 2;

[0124] A2: Select a location and construct the fishway structure using the structural parameters and location parameters of the fishway.

[0125] The invention provides a construction method for a fishway structure, which fully considers the coordinated migration of eels and other fishes, and the design method can provide assistance for the construction. The whole process is scientific, systematic, efficient and of good quality.

[0126] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A fishway structure, characterized in that: The invention comprises a migratory channel (20), wherein a plurality of rows of pile structures (22) are arranged at the bottom of the migratory channel (20), wherein at least two pile structures (22) are arranged at intervals in each row, and the pile structures (22) in adjacent rows are staggered along the length direction of the migratory channel (20).

2. A fishway structure according to claim 1, characterized in that: The bottom diameter of the pile structure (22) is greater than the top diameter of the pile structure (22).

3. A fishway structure according to claim 2, characterized in that: The pile structure (22) comprises a plurality of forwardly arranged frustum piles, the lower portion of the frustum piles being connected to the bottom of the migratory channel (20), the top of the frustum piles being closed, and the height of the frustum piles being greater than the bottom diameter of the frustum piles.

4. A fishway structure according to claim 2, characterized in that: The pile structure (22) is a tubular structure, the lower part of which is connected to the bottom of the migratory channel (20), the upper part of which is open, and a through hole (21) is provided on the upstream side of the tubular structure; the upper edge of the tubular structure and the edge of the through hole (21) are in a circular arc transition; the height of the tubular structure is greater than the bottom diameter of the tubular structure, and the top diameter of the tubular structure is smaller than the bottom diameter of the tubular structure.

5. The fishway structure according to claim 1, characterized in that: The migratory channel (20) comprises a driving mechanism, a four-bar linkage, a base and a slot structure, the base is arranged obliquely, the pile structure is arranged at the bottom of the slot structure, and the driving mechanism drives the four-bar linkage to drive the slot structure to reciprocate and slide with the base.

6. A fishway structure according to any one of claims 1 to 5, characterized in that: The invention comprises an eel way (24) and a vertical slot fishway (23), wherein the migratory fish in the eel way (24) include eels and mitten crabs, and the migratory fish in the vertical slot fishway (23) include red-eyed trout and dace. The eel way (24) and the vertical slot fishway (23) are located on the same side of the canal, one end of the eel way (24) is connected to the middle of the vertical slot fishway (23), and the other end extends to the bottom of the canal. The eel way (24) and the vertical slot fishway (23) located upstream of the eel way (24) form the migratory channel (20); A water retaining structure is arranged at intervals in the part of the vertical slit fishway (23) located upstream of the eel way (24), and a pool chamber (30) is formed between adjacent water retaining structures. The water retaining structure includes a partition (32) and a guide plate (35) arranged opposite to each other, the guide plate (35) is smaller in width than the partition (32), and a vertical slit (31) for fish to pass through is provided between the partition (32) and the guide plate (35). A plurality of rows of pile structures (22) are also arranged in the pool chamber (30), wherein at least two pile structures (22) are arranged at intervals in each row, and adjacent rows of pile structures (22) are staggered with each other along the length direction of the migratory channel.

7. A method for designing a fishway structure according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Based on the migratory ecological characteristics of the fish passage objects and the initial technical parameters of the fishway, the design flow rate of the eel way (24) and the design flow rate of the vertical slot fishway (23) are determined. The design flow rate of the vertical slot fishway (23) includes the flow rate through the fish hole / slot, the inlet fish attracting flow rate, the outlet flow rate and the main structure flow rate of the vertical slot fishway (23). S2. Determine the layout positions of the vertical slot fishway (23) and the eel way (24), and the position where the eel way (24) is connected to the vertical slot fishway (23) based on the initial technical parameters of the fishway, the design flow velocity of the eel way (24), the design flow velocity of the vertical slot fishway (23), and the tailwater position of the power station (27) in the hub (1); S3: Determine the design water level at the vertical slot fishway outlet (25) based on the layout positions of the vertical slot fishway (23) and the eel way (24), the design water storage level of the hub (1) and the water level fluctuation parameter; and determine the design water level at the vertical slot fishway inlet (26) based on the average low tide level of the tidal river section downstream of the hub (1), the water level fluctuation and the cumulative frequency of low tides below the lock of the hub (1); S4: determining an angle parameter between the axis of the vertical slot fishway inlet (26) and the riverbed water flow and a width parameter of the vertical slot fishway inlet (26) based on a design water level at the vertical slot fishway outlet (25) and a design water level at the vertical slot fishway inlet (26); S5: Determine the width of the vertical slot fishway (23) based on the width parameter of the vertical slot fishway inlet (26); S6: determining structural parameters of the vertical slot fishway (23) based on the design water level at the vertical slot fishway outlet (25), the design water level at the vertical slot fishway inlet (26), the size of the largest fish passing object in the fish passing specification, and the width of the vertical slot fishway (23); S7: Design the structural position of the eelway and the arrangement parameters of the pile structure (22) based on the structural parameters of the vertical slot fishway (23). The preliminary design scheme of the fishway structure was obtained.

8. A method for designing a canal fishway according to claim 7, characterized in that: The structural parameters of the vertical slot fishway (23) include the bottom slope of the fishway, the designed flow velocity of the fishway and the total length of the fishway. The relationship between the bottom slope I of the fishway, the designed flow velocity v of the fishway and the total length L of the fishway is specifically as follows: Where I is the bottom slope of the fishway; n is the number of chambers (30); v is the design flow velocity of the fishway; g is the acceleration due to gravity; is the flow rate coefficient of the partition (32); l y is the net length of the pool room (30); k2 is the net length ratio coefficient; k1 is the number ratio coefficient; and L is the total length of the fishway.

9. The method for designing a canal fishway according to claim 7, characterized in that: The vertical slot fishway (23) and the eel way (24) are both arranged on the tailwater side of the hub (1).

10. A construction method, characterized in that: The following steps are involved: A1: Use the design method described in any one of claims 7 to 9 to design the structural parameters and position parameters required for the fishway (2); A2: Using the structural parameters and location parameters of the fishway (2) to select a location and construct the fishway structure.

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