Structure, construction method and design method of canal fishway

Abstract

The invention relates to the technical field of fishways, in particular to a canal fishway structure, construction and design method.The canal fishway structure, construction and design method comprises the following steps that S1, a hub fishway database is established, the swimming capacity of target fishes passing through a fishway is evaluated, and the migration ecological characteristics of the fish passing objects are determined; s2, designing a fishway scheme, and determining a fishway structure preliminary design scheme; s3, designing a fishway engineering local section physical model, and performing a fishway engineering local section physical model test to obtain a pool chamber structure recommendation scheme located at the upstream of the eel way in the vertical seam type fishway; and S4, establishing a fishway overall model, and performing a fishway overall model test to determine a fishway overall structure scheme. According to the design method of the canal fishway, a theoretical basis is provided for arranging an eel fishway suitable for migration of eels and eriocheir hepuensis and a vertical seam type fishway suitable for migration of squaliobarbus curriculus and dace, and then migration channels are provided for the eels, the squaliobarbus curriculus, the sinilabeo, the river perches, the eriocheir hepuensis and the like.

Description

Technical Field

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

[0002] At present, the canal, as an important part of the new land-sea channel, is becoming more and more important. Compared with land transportation, the canal has the advantages of low energy consumption cost, low transportation cost and high transportation efficiency. It opens up a more convenient and economical sea outlet in the inland area, and accelerates the construction of a relatively complete Beibu Gulf port facilities system in accordance with the requirements of building a world-class port and the standards of major coastal ports and international hub ports across the country.

[0003] After the permanent river-blocking structures were built on the canal, the original continuous river ecosystem was divided into discontinuous environmental units. The most direct adverse impact on fish is the blocking of migration channels. This is often devastating for migratory and semi-migratory species that need to migrate over a large area to complete their life history. They cannot reach their original breeding grounds or feeding grounds to complete their life history, and their resource quantity will be seriously affected. For species that can complete their life history in local waters, it may affect the genetic exchange between groups in different waters, resulting in a decrease in the overall genetic diversity of the population and the degradation of fish quality. For some rare and endangered fish, they may face the risk of extinction. In order to ensure the migration of canal fish, fishway projects must be set up at the hub.

[0004] Therefore, how to provide suitable migration channels for eels, red-eyed trout, dace, perch, Hepu mitten crab, etc. has become an important problem to be solved by technicians in this field. Summary of the invention

[0005] The purpose of the present invention is to overcome the problem of how to provide a migration channel for eels, red-eyed trout, dace, river perch, Hepu mitten crab, etc. in the background technology, and to provide a structure, construction and design method of a canal fishway.

[0006] A method for designing a canal fishway comprises the following steps:

[0007] S1: Establish a fishway database at the hub, evaluate the swimming ability of target fish species passing through the fishway, and determine the migratory ecological characteristics of the target fish species;

[0008] S2: Based on the ecological characteristics of the migration of fish objects and the fishway database at the hub, the fishway scheme is designed to determine the preliminary design scheme of the fishway structure. The fishways in the preliminary design scheme of the fishway structure include eel ways and vertical slot fishways. The migratory fish in the eel way include eels and Hepu mitten crabs, and the migratory fish in the vertical slot fishway include red-eyed trout and dace. 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.

[0009] S3: Based on the preliminary design of the fishway structure, a local cross-section physical model of the fishway project is designed, and a local cross-section physical model test of the fishway project is conducted to obtain a recommended scheme for the pool chamber structure located upstream of the eel passage in the vertical slot fishway;

[0010] S4: Establish an overall model of the fishway based on the preliminary design scheme and the recommended pool structure scheme, and conduct an overall model test of the fishway to determine the overall structural scheme of the fishway.

[0011] The present application discloses a method for designing a canal fishway, which establishes a fishway database at a hub, evaluates the swimming ability of target fish species passing through the fishway, determines the migratory ecological characteristics of the target fish species, designs a fishway scheme, determines a preliminary design scheme for the fishway structure, confirms the layout form of an eel way suitable for the migration of eels and Hepu mitten crabs and a vertical slot fishway suitable for the migration of red-eyed trout and dace, and the structural form after merging, and then obtains a recommended scheme for the pool chamber structure located upstream of the eel way in the vertical slot fishway through a physical model test of a local section of the fishway project, and puts the recommended scheme for the pool chamber structure into an overall fishway model, and conducts an overall fishway model test to determine a preferred overall fishway structural scheme, thereby providing a theoretical basis for setting up an eel way suitable for the migration of eels and Hepu mitten crabs and a vertical slot fishway suitable for the migration of red-eyed trout and dace, thereby solving the problem of providing a migration channel for eels, red-eyed trout, dace, river perch, Hepu mitten crabs, etc.

[0012] Preferably, in step S1, evaluating the swimming ability of the target fish passing through the fishway and determining the migratory ecological characteristics of the target fish passing through the fishway comprises the following steps:

[0013] S11. Confirm the hub structure and the purpose of fish passage at the hub; S12. Classify the estuarine fish community based on the interaction of freshwater runoff and seawater intrusion, and obtain the classification results of fish passage; S13. Confirm the ecological habits of each fish passage based on the classification results, and determine the fish passage specifications and season based on the ecological habits of each fish, as well as formulate the initial technical parameters of the fishway, and obtain the fish that meet the requirements, wherein the initial technical parameters of the fishway include the number of fishways 2, the design flow rate of the fishway, the layout of the fishway, the structure of the fishway, the inlet of the fishway, the outlet of the fishway, the water consumption of the fishway and the operating water level of the fishway; S14. Confirm the fish passage time period of the fishway at the hub based on the fish passage season; S15. During the fish passage time period confirmed in step S14, test the swimming ability of the fish obtained in step S13 at the hub, and obtain the swimming ability test results of different fish, so as to clarify the migratory ecological characteristics of the hub fish passage objects.

[0014] Preferably, the design flow rate of the fishway includes the flow rate through the fish orifice of the fishway, the fish attracting flow rate at the fishway inlet and the minimum induced flow rate in the fishway.

[0015] Preferably, the fish's flow-taxis characteristics and ability to resist flow are tested, and the test indicators include induced flow velocity, critical swimming speed and surging swimming speed. Preferably, the induced flow velocity test is specifically as follows: placing more than 10 fish in a test annular test tank, gradually increasing the flow velocity until half of the test fish turn to the upstream direction, at which time the flow velocity is the induced flow velocity of the test fish group; placing the test fish alone in the still water of the test annular test tank, and then gradually increasing the flow velocity until the test fish turn to the upstream direction, at which time the flow velocity is the induced flow velocity of the individual test fish.

[0016] Preferably, the critical swimming speed test is specifically as follows: the length and weight of the tested fish are placed in the swimming area of ​​a circular test tank, and the initial flow velocity, flow velocity gradient and time gradient of the circular test tank are set; the dissolved oxygen and temperature are tested at regular intervals, and when the fish reaches the end grid of the swimming area and cannot swim, the fish is removed from the swimming area and the weight of the fish is tested, assuming that the swimming speed of the fish is equal to the water flow velocity, and ignoring the retention effect, so as to calculate the critical swimming speed.

[0017] Preferably, the swimming ability of the tested cutlass anchovy is analogous to that of the seven-filament anchovy.

[0018] Preferably, step S2 specifically includes the following steps: S21. Determine 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 migration of fish 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 hole / slot, the inlet fish attracting flow rate, the outlet flow rate and the main structure flow rate of the vertical slot fishway. S22. Determine the layout positions of the vertical slot fishway and the eel way, as well as the position where the eel way connects to the vertical slot fishway based on the fishway database at the hub, the initial technical parameters of the fishway, the design flow rate of the eel way, the design flow rate of the vertical slot fishway and the tailwater position of the power station in the hub; S23: Determine the design water level at the outlet of the vertical slot fishway based on the layout positions of the vertical slot fishway and the eel way, the design water storage level of the hub and the water level fluctuation parameters; and determine the design water level at the inlet of the vertical slot fishway 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 tides under the hub gate; S24: Determine the design water level at the outlet of the vertical slot fishway based on the vertical slot fishway. 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 determine the angle parameters between the inlet axis of the vertical slot fishway and the riverbed water flow, as well as the inlet width parameters of the vertical slot fishway; S25: determine the width of the vertical slot fishway based on the inlet width parameters of the vertical slot fishway; S26: determine the structural parameters of the vertical slot fishway based on the design water level at the outlet of the vertical slot fishway, the design water level at the inlet of the vertical slot fishway, the size of the largest fish passing object in the fish passing specifications and the width of the vertical slot fishway; S27: design the structural position of the eel way and the arrangement parameters of the pile structure based on the structural parameters of the vertical slot fishway, and obtain a preliminary design scheme of the fishway structure.

[0019] 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: 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.

[0020] Preferably, step S3 specifically includes the following steps: S31. Designing a local cross-section physical model of the fishway project based on a preliminary design scheme, wherein the local cross-section physical model of the fishway project is designed as a normal model, and the local cross-section physical model of the fishway project is designed according to the gravity similarity criterion, and the overall fishway model design scheme is checked for geometric similarity, water flow motion similarity and dynamic similarity; S32. Conducting a fishway cross-section model test, measuring and evaluating fishway parameters, and finding parameters that exceed the standard and the reasons for the parameters exceeding the standard, wherein the fishway parameters include the upstream and downstream water level difference between adjacent pool chambers, the vertical seam flow velocity distribution, the flow field distribution in the pool chamber, the flow state in the pool chamber and the local water flow in the pool chamber, and the average water depth of each pool chamber, the average water level difference of each pool chamber, the vertical seam flow velocity distribution of each pool chamber, and the flow field distribution in the pool chamber; S33. Repeating S31-S33 after improving the reasons in S32 until all fishway parameters meet the design requirements, and forming a recommended pool chamber structure scheme based on the fishway parameters.

[0021] Preferably, in step S31, based on the preliminary design plan of the vertical slot fishway, the designed bottom slope I of the pool chamber, the average low tide level at the estuary, the operating water level at the vertical slot fishway outlet, and the minimum water depth in the pool chamber are determined; the corresponding upstream design low water level condition of the fishway, the corresponding downstream design low water level condition of the fishway and the most unfavorable design condition are determined, and based on the designed bottom slope I of the pool chamber, the average low tide level at the estuary, the operating water level at the vertical slot fishway outlet, the minimum water depth in the pool chamber, the corresponding upstream design low water level condition of the fishway, the corresponding downstream design low water level condition of the fishway and the most unfavorable design condition, a local section physical model of the fishway project is designed, wherein the most unfavorable design condition is a condition in which the volume of the energy dissipation water body is minimum on the basis of unchanged geometric scale of the pool chamber.

[0022] Preferably, in step S32, when conducting a fishway cross-section model test, the upstream flat water channel and the downstream overflow plate are used to control the upstream and downstream water levels to be constant, and a number of water gauges are arranged along the fishway cross-section model to measure the water level in the pool chamber. The flow field in the pool chamber and the vertical slit is collected at a single point using an acoustic Doppler flow meter.

[0023] Preferably, in step S32, the flow velocity distribution of the vertical seam is evaluated as follows: flow velocity is measured for at least part of the vertical seams, a plurality of measuring points are arranged at vertical intervals along the water depth on the center line of each vertical seam, and the flow velocity distribution and average flow velocity of the vertical seam are obtained based on the measuring points; a recommended range of the flow velocity distribution of the vertical seam and a recommended average flow velocity value are obtained based on the swimming ability test results of the target fish species; it is evaluated whether the flow velocity distribution of the vertical seam exceeds the recommended range of the flow velocity distribution of the vertical seam, and whether the average flow velocity of the vertical seam is greater than the recommended average flow velocity value of the vertical seam; and a baffle flow velocity coefficient is obtained based on the average flow velocity of the vertical line of the fish-passing vertical seam, the average water level difference of the baffle, the average flow rate of the fishway, and the water volume of the pool chamber. and the power dissipation E per unit water volume in the pool chamber, and the baffle velocity coefficient And the unit water power dissipation E of the pool chamber meets the design requirements.

[0024] Preferably, the vertical slots in the vertical slot fishway allow the liquid flow rate to pass through to be in the range of 0.54 to 1.37 m / s, and the average flow rate is 1.0 m / s.

[0025] Preferably, in step S32, the flow field distribution in the pool chamber is evaluated as follows: a pool chamber is selected to measure its surface flow field distribution, N measuring lines are set along the width of the pool chamber, and L measuring points are arranged along the length of the pool chamber on each measuring line; based on the test results of the measuring points, the mainstream entry form, mainstream path, circulation position and integrity of the recirculation zone of the pool chamber are evaluated, wherein the recirculation zone influence range K3 and the maximum flow velocity v of the recirculation zone are used to evaluate the flow field distribution on the surface of the pool chamber; cmax To quantify the impact of the recirculation zone on fish.

[0026] Preferably, the minimum value of the mainstream flow in the pool chamber and the average flow velocity of the vertical seams are obtained based on the test results of the measuring points, and the energy dissipation rate of the pool chamber is reflected by the ratio of the minimum value of the mainstream flow in the pool chamber to the average flow velocity of the vertical seams, so as to obtain the energy dissipation rate of the pool chamber of the design scheme.

[0027] Preferably, the influence range K3 of the recirculation zone and the maximum flow velocity v of the recirculation zone are cmax To quantify the impact of the recirculation zone on fish, specifically:

[0028] K3=L c B c / (LB), where L c is the maximum length of the recirculation zone, B c is the maximum width of the recirculation zone.

[0029] Preferably, when the influence range of the recirculation zone is too large, based on the diversion angle at the vertical seam in the preliminary design scheme, at least a second diversion angle and a third diversion angle are set, and the second diversion angle and the third diversion angle are respectively substituted into the local section physical model of the fishway engineering to form a new local section physical model of the fishway engineering, and a new fishway section model test is carried out to obtain the average flow velocity of the vertical seam at each diversion angle, the maximum flow velocity of the vertical seam, and the minimum flow velocity of the vertical seam, and obtain an optimized structural scheme, wherein the second diversion angle and the third diversion angle are both greater than the diversion angle at the vertical seam in the preliminary design scheme.

[0030] Preferably, the water level difference in the pool chamber, the vertical seam flow velocity distribution and the flow field distribution in the pool chamber are calculated based on the optimized structural scheme, and it is confirmed whether the water level difference in the pool chamber, the vertical seam flow velocity distribution and the flow field distribution in the pool chamber meet the design requirements. If so, the optimized structural scheme is the recommended scheme for the pool chamber structure.

[0031] Preferably, the influence range K3 of the reflow zone is 0.12-0.17; and the reflow intensity range is 0.18-0.24 m / s.

[0032] Preferably, step S4 specifically includes the following steps: S41: establishing a fishway overall model design scheme based on the preliminary design scheme and the recommended pool chamber structure scheme; S42: making a fishway overall model based on the fishway overall model design scheme; S43: conducting a fishway overall model test based on the fishway overall model, optimizing the fishway overall layout structure scheme and operation scheme, so as to obtain the final fishway overall structure scheme.

[0033] Preferably, the overall model of the fishway is designed as a normal model, and the overall model of the fishway is designed according to the gravity similarity criterion, and the overall model design scheme of the fishway is checked for geometric similarity, water flow motion similarity and dynamic similarity to form an optimized design scheme of the overall model of the fishway.

[0034] Preferably, in step S42, the plane lofting of the overall fishway model adopts a plane wire control system.

[0035] Preferably, step S41 specifically includes the following steps: establishing a basic structural scheme for the overall model design of the fishway based on the preliminary design scheme; establishing a pool chamber structure scale scheme based on the optimized local section structure scheme of the fishway project, and adding the pool chamber structure scale scheme to the basic structural scheme for the overall model design of the fishway to obtain the overall model design scheme of the fishway; selecting experimental conditions according to the design operating water level upstream of the fishway and the design operating water level downstream of the fishway; conducting an overall model test of the fishway based on the production of the overall model of the fishway and various experimental conditions to obtain the water depth in each pool chamber and the average drop between the pool chambers in each condition.

[0036] Preferably, the experimental operating conditions include the upstream highest operating water level condition, the upstream lowest operating water level condition, the downstream lowest operating water level condition, the condition where the inlet water depth is consistent with the outlet water depth when the upstream highest water level is reached, and the highest operating water level condition.

[0037] Preferably, based on the overall model test of the fishway, the vertical slot flow velocity, the flow velocity and flow pattern in the pool chamber, the flow velocity and flow pattern in the rest pool, and the flow velocity and flow pattern at the inlet and outlet of the vertical slot fishway are obtained under various working conditions.

[0038] Preferably, when the flow rate in the vertical slits in the fishway body and the fish pond exceeds the design requirements, the flow rate of the vertical slit fishway body is reduced to adapt to the water depth of the lower section of the fishway under low water level conditions.

[0039] Preferably, when the vertical seams in the fishway body and the flow velocity in the fish pond exceed the design requirements, the water depth of the pool where the flow velocity exceeds the standard is increased and the flow velocity is reduced.

[0040] Preferably, when the flow rate at the fishway inlet is too low, a water replenishment device is provided at the inlet.

[0041] The present application also discloses a structure of a canal fishway, which is designed by the design method of the canal fishway of the present application. The structure of the canal fishway includes an eel way and a vertical slot fishway. Migratory fish in the eel way include eels and mitten crabs, and migratory fish in the vertical slot fishway include red-eyed 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. A climbing matrix is ​​arranged in the eel way, and a part of the vertical slot fishway located upstream of the eel way is arranged at intervals with water retaining structures, and a pool chamber is formed between adjacent water retaining structures. The water retaining structure includes a partition and a guide plate arranged oppositely, the guide plate has a width smaller than the partition, and a vertical slot for fish to pass through is provided between the partition and the guide plate. A climbing matrix is ​​also arranged in the pool chamber, and the climbing matrix includes a plurality of pile structures, wherein each row is arranged at intervals with at least two pile structures, and adjacent pile structures are staggered along the length direction of the eel way and the vertical slot fishway.

[0042] The structure of a canal fishway of the present application provides climbing assistance for eels by staggering the pile structures and adjacent rows of pile structures along the length direction of the eel way or the vertical slot fishway. At the same time, compared with the bristle base, the pile structure does not have bristles, so there is no clogging of debris and it is easy to clean. Moreover, the pile structure can dissipate energy by friction resistance along the way, water flow counteraction and diffusion, thereby improving the flow state and reducing the flow velocity in the vertical slot passing through the fish.

[0043] The present application also discloses a fishway construction method for forming the structure of the canal fishway of the present application, comprising the following steps: S1: constructing a vertical slit fishway; S2: constructing an eel way and connecting the eel way with the vertical slit fishway; S3: adjusting the slope and diversion angle of the eel way.

[0044] The fishway construction method of the present application takes the canal fishway design method of the present application as the theoretical basis, first constructs the vertical seam fishway, then constructs the eel way, and finally adjusts the slope and diversion angle of the eel way. The whole process is simple to construct and has low construction cost.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] The structure of a canal fishway in the present application solves the problem of providing migration channels for eels, red-eyed trout, dace, river perch, Hepu mitten crabs, etc. by setting up an eel channel suitable for the migration of eels and Hepu mitten crabs and a vertical slit fishway suitable for the migration of red-eyed trout and dace. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 is the correlation between various fish and body length in this application; among them, Figure 1 a The correlation between the flow velocity sensed by eels and their body length; Figure 1 b The correlation between the critical swimming speed and body length of eels; Figure 1 c The correlation between the eel's plunging swimming speed and body length; Figure 1 d The correlation between the induced flow velocity and body length of Lateolabrax japonicus; Figure 1 e The correlation between the critical swimming speed and body length of Lateolabrax japonicus; Figure 1 f The correlation between the lunging swimming speed and body length of Lateolabrax japonicus; Figure 1 g The correlation between the flow velocity sensed by red-eyed trout and its body length; Figure 1 h The correlation between the critical swimming speed and body length of redeye trout; Figure 1 j The correlation between the speed of the red-eyed trout's lunge and its body length; Figure 1 k The correlation between the induced flow velocity and body length of dace; Figure 1 The correlation between critical swimming speed and body length of m. Figure 1 n Correlation between the lunging swimming speed and body length of dace.

[0048] Figure 2 This is a schematic diagram of the optimized fishway layout for this application.

[0049] Figure 3 This is a schematic diagram of the vertical seam pool chamber structure of this application.

[0050] Figure 4 This is a schematic elevation diagram of the Eel Road for this application.

[0051] Figure 5 For this application, the Eel Road floor plan.

[0052] Figure 6 Schematic diagram of the location of the eel way and vertical slot fishway for this application.

[0053] Figure 7This is a schematic diagram of the local model scope of this application.

[0054] Figure 8 This is a schematic diagram of the water level distribution along the pool chamber of this application.

[0055] Fig. 9 This is a schematic diagram of the vertical distribution of flow velocity in the vertical seam of this application. Fig. 9 a is a schematic diagram of vertical measurement point distribution. Fig. 9 b is a schematic diagram of the vertical distribution of flow velocity.

[0056] Fig.10 This is a schematic diagram of the distribution of flow velocity measurement points in the pool room for this application.

[0057] Fig.11 This is a schematic diagram of the flow pattern in the pool chamber of the preliminary design scheme of the fishway structure of this application, in which: Fig.11 a is a schematic diagram of the actual flow pattern in the pool chamber of the preliminary design of the fishway structure in this application. Fig.11 b is a vector diagram of the flow pattern and flow field in the pool chamber of the preliminary design scheme of the fishway structure of this application.

[0058] Fig.12 This is a schematic diagram of the flow velocity distribution along different measuring lines in this application (Vx and Vy are vectors, ∑V is a scalar, and θ is the angle with the positive x-axis).

[0059] Fig.13 This is a schematic diagram of the plan structure of the pool chamber in the recommended pool chamber structure for this application.

[0060] Fig.14 Schematic diagram of vertical distribution of flow velocity in the vertical slit of a single-sided vertical slit fishway at different diversion angles in this application.

[0061] Fig.15 Schematic diagram of vertical distribution of flow velocity in vertical slits of different fishway schemes in this application.

[0062] Fig.16 Schematic diagram of typical pool flow fields for different fishway schemes in this application.

[0063] Fig.17 The distribution of mainstream flow velocity along the fishway chamber for different fishway schemes in this application.

[0064] Fig.18 This is the schematic diagram of the pool room layout recommended for this application, where: Fig.18 a is the schematic diagram of the pool room layout recommended for this application. Fig.18 b is a schematic diagram of the three-dimensional layout of the pool room recommended for this application.

[0065] Fig.19 This is a schematic diagram of the water level distribution along the pool chamber recommended for this application.

[0066] Fig. 20This is a schematic diagram of the vertical distribution of flow velocity in the vertical seam of the recommended solution for this application.

[0067] Fig.21 This is the schematic diagram of the flow field distribution in the pool chamber recommended for this application, where: Fig.21 a is a schematic diagram of the flow field distribution in the pool chamber recommended for this application. Fig.21 b is a schematic diagram of the flow field vector in the pool chamber recommended for this application.

[0068] Fig. 22 The flow velocity distribution along the different measuring lines of the recommended solution for this application (Vx and Vy are vectors, ∑V is a scalar, and θ is the angle with the positive x-axis).

[0069] Fig.23 This is a schematic diagram of the overall model layout of the fishway in this application.

[0070] Fig.24 This is a schematic diagram of the planar structural dimensions of the pool chamber for this application.

[0071] Fig.25 This is a schematic diagram of the water level along the fishway under various working conditions in the design scheme for this application.

[0072] Fig.26 This is a schematic diagram of the vertical joint flow rate under various working conditions of the design scheme for this application.

[0073] Fig. 27 This is a schematic diagram of the water flow pattern in the pool chamber of this application.

[0074] Fig.28 Schematic diagram of the change of mainstream flow velocity in the pool chamber under various working conditions of this application.

[0075] Fig.29 This is a flow diagram of the 4# rest pool for this application.

[0076] Fig.30 This is a flow diagram of the rest pool and observation room channel for this application, where: Fig.30 a is a schematic diagram of the flow pattern of the 3# rest pool and the observation room channel. Fig.30 b is the flow pattern diagram of 1# and 2# rest pools and the observation room channel. Fig.30 c is a schematic diagram of the actual flow state at the inlet of the vertical slot fishway in this application.

[0077] Fig.31 This is a schematic diagram of the preferred arrangement of the pile structure in the eel way of this application.

[0078] Fig.32 This is a schematic diagram of the flow field near the inlet and outlet of the vertical slot fishway in this application, where: Fig.32 a is a schematic diagram of the flow field near the entrance of the vertical slot fishway. Fig.32 b is a schematic diagram of the flow field near the exit of the vertical slot fishway.

[0079] Fig.33 This is the layout diagram of the vertical slot fishway for Optimization Scheme 1 of this application.

[0080] Fig.34 This is a schematic diagram comparing the vertical seam flow velocities of the optimized scheme 1 and the design scheme for working condition 1 of this application.

[0081] Fig.35 This is a schematic diagram comparing the water surface lines along the fishway of the optimized scheme 1 and the design scheme for working condition 4 of this application.

[0082] Fig.36 This is the layout diagram of the vertical slot fishway for optimized solution 2 of this application.

[0083] Fig.37 This is a schematic diagram of the water level along the fishway under various working conditions for Optimization Scheme 2 of this application.

[0084] Fig.38 This is a schematic diagram of the vertical joint flow velocity under various working conditions of optimization scheme 2 of this application.

[0085] Fig.39 Schematic diagram of the mainstream flow velocity in the pool chamber under various working conditions for Optimization Scheme 2 of this application.

[0086] Fig.40 This is a schematic diagram of the inlet flow pattern of the optimized solution for this application. DETAILED DESCRIPTION

[0087] The present invention is further described in detail below in conjunction with specific embodiments. However, it should not be understood that the scope of the above subject matter of the present invention is 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.

[0088] 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.

[0089] Example 1

[0090] like Figure 1-Figure 40 As shown, the design method of a canal fishway described in this embodiment includes the following steps:

[0091] 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.

[0092] 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-ridged Chinese fish [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.

[0093] 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.

[0094] 2. Design of fishway 2 scheme, propose a preliminary design scheme of fishway structure, the preliminary design scheme of fishway structure includes the preliminary design scheme of fishway plane and pool chamber 30 structure layout.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] The specific preferred steps are as follows:

[0103] S1: Evaluate the swimming ability of target fish species passing through the fishway and determine the migratory ecological characteristics of the target fish species.

[0104] I. Confirm the structure of hub 1: The structure of hub 1 includes double-line ship lock, water retaining dam, flood gate, bottom outlet and power station 27. The double-line ship lock is arranged on the left side, and the water retaining dam section is arranged on the left and right bank slopes of the double-line ship lock and the left and right bank slopes of the flood gate. The water retaining dam is arranged on both sides of the upper gate of the double-line ship lock and the bank slope dam section on both sides of the flood gate. There are 4 dam sections arranged on the left bank of the upper gate of the double-line ship lock; there are 4 dam sections arranged on the right bank of the upper gate of the double-line ship lock, of which 2 dam sections are the gate dam sections of the upper gate of the ship lock for maintenance, and the cross-slot arrangement is adopted; there are 4 dam sections arranged on the left bank of the flood gate; there are 7 dam sections arranged on the right bank of the flood gate, one of which is the gate dam section of the flood gate for maintenance, and the 7-hole flood gate is arranged in the main river channel, and the hole splitting is adopted. A 20.0m long blanket is set upstream of the flood gate, and the blanket top elevation is set to -8.00~0.00m according to the gate bottom elevation. The flood discharge gate weir type adopts a wide crest weir, and the weir crest elevation is 1.00m. The flood discharge gate is connected to the seafloor through a slope of 1:5. The seafloor is 100m long, and a riprap anti-scouring trough is set at the end. The bottom hole dam section is arranged on the left bank, adjacent to the powerhouse dam section on the left, and the flood discharge gate is immediately on the right. The hole width is 2.0m, the gate piers on both sides are 5.5m thick, and the right side is a 6.5m wide half-hole flood discharge gate; the total width of the dam section is 19.5m, and the length of the dam section along the water flow direction is 35.0m. The gate and reservoir dam section is divided into two parts: to place the inspection gate of the upper gate of the double-line ship lock, the gate and reservoir are arranged on the right bank of the ship lock. The gate and reservoir adopt a cross-slit arrangement, and the two dam sections are arranged in combination with the ship lock; to place the inspection gate of the flood discharge gate, a gate and reservoir dam section is set on the right side of the flood discharge gate; the dam crest elevation is arranged in combination with the flood discharge gate traffic bridge and the gantry crane track. Power station 27 is a riverbed power station. The riverbed power station building is arranged on the left side of the right bank flood discharge gate. The main buildings of the power station include the water intake gate, main power plant, auxiliary power plant, installation room and tailwater channel.

[0105] 2. Based on the interaction between freshwater runoff and seawater intrusion, the estuarine fish community is classified, and the classification results of fish passing through are obtained. Based on the classification results of fish passing through, the ecological habits of each fish are confirmed, the number of fishways 2 is determined, the fish passing specifications are confirmed, and fish that meet the requirements are obtained; the fish passing through objects include endemic species, river-sea migratory species, and semi-migratory species.

[0106] Fishway 2 is designed for multiple target fish species, including eels, mitten crabs, red-eyed trout, river perch, and dace; eels include eels and flower eels, both of which are migratory fish from the ocean to rivers, that is, they are downstream migratory fish.

[0107] According to the survey of the current status of fish resources in the canal impact area, flower eels, eels, red-eyed trout, dace, river perch, and Hepu mitten crabs are listed as the main fish species that pass through the project. The ecological habits of the main fish species are as follows: Flower eels: In winter, they migrate downstream to the river mouths near the river mouths and their gonads begin to develop, and then they enter the deep sea to spawn and reproduce. From March to April every year, young eels enter the river mouths to feed and grow. Eels: Originated in the sea, they migrate upstream to fresh water to grow up, and then return to the sea to spawn. In spring, young eels [also known as white eels and eel lines] enter the river mouths from the sea in groups. Male eels grow in the river mouths; female eels swim upstream to enter the main and tributary rivers. Hepu mitten crabs: They are downstream migratory crustaceans. The larvae metamorphose into crablets and migrate upstream to rivers and lakes to grow. River perch: Inhabits the middle and lower layers of coastal waters, can live at the junction of freshwater and saltwater in estuaries, or in freshwater. Usually matures sexually at the age of 3, can reach a body length of 600mm, begins to reproduce at the end of winter, spawns in the brackish freshwater area of ​​estuaries, and mainly concentrates in the breeding and migratory season from February to October. Red-eyed trout: A fish in the middle layers of rivers, with strong adaptability. Good at jumping, the reproductive season is generally from April to September. The eggs are light green and sink. Dace: Inhabits water bodies with higher water temperatures, the water temperature cannot be lower than 7℃, and hibernates in the deep water of rivers. A fish in the middle and lower layers of rivers. The reproductive cycle of dace is relatively long, usually starting in April and May, and extending to August and September, and spawning is mostly in floods. Seven-thread anchovy: It is an upstream migratory fish, its hatching and early life history need to be completed in freshwater, and in the subsequent growth and development stages, it flexibly travels back and forth between the brackish water and freshwater areas of the estuary. The migration activities of seven-thread anchovy are more diverse. Flower croaker [yellow croaker]: Lives in brackish and freshwater areas, and migrates to estuaries or inland rivers to spawn during the spawning season [April-August]. Chinese black snakehead: The Chinese black snakehead can tolerate a salinity of 0-35‰, with a more suitable salinity of 10-25‰, and a suitable salinity of about 15‰ for seedlings. The Chinese black snakehead can tolerate a temperature range of 6.0-35.0℃, with an ideal water temperature of 25-30℃. In summary, the season for fish passing through: Flower eels and eels swim upstream from February to April, river crabs descend to the river to spawn from September to November, and river perch reproduce and migrate from February to September, so the key season for fish passing through is February to November.

[0108] Initial technical parameters of fishway

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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 is as follows: the outlet of the fishway 2 is located in the reservoir area upstream of the sluice gate, and the outlet elevation is 17m.

[0113] 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.

[0114] The ecological water consumption of hub 1 in the dry season is 6.36m3 / s, the ecological water consumption in the flood season is 16.74m3 / s, and the water consumption of the fishway in hub 1 is 0.8m3 / s.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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

[0119] Table 1: Fishway scale table

[0120]

[0121] 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] Swimming ability test: There are four methods for testing fish swimming ability: fish moving in a straight line in a still water tank, bait is delivered at both ends, fish moving back and forth, underwater cameras are used to record fish movement behavior and the swimming speed and swimming ability of fish are estimated based on the movement distance and time. Using a large diameter still water circular tank, fish move following visual markers, and the moving speed of the visual markers ranges from 0 to 4.5 m / s. Fish move in a circular tank, and the water flow in the tank is manually controlled and set. The swimming speed and swimming ability of fish are estimated based on the position of fish movement and water flow rate. Using a portable circular tank, fish move in a specific swimming area in the tank, and the water flow rate is manually controlled and set. The swimming speed and swimming ability of fish are estimated based on the water flow rate.

[0134] Test time and location: The test time is September-October; the test location is near Hub 1.

[0135] Test fish: Based on the types of fish passing through the previous stage, the types of fish passing through after review, and the availability of fish in the canal section. The swimming ability of sea bass and eel was tested, supplemented by red-eyed trout, dace, and other fish currently distributed in this section of the river. And by consulting the data, the swimming ability of fish of similar species and body size to the fish passing through was compared to comprehensively determine the design flow rate of the fishway at the hub. Test fish specifications: eel, body length 18.5-26.8cm, average body length 22.0cm; sea bass, body length 33.0-37.0cm, average body length 35.5cm; red-eyed trout, body length 17.5-28.4cm, average body length 22.3cm; dace, body length 16.8-27.1cm, average body length 20.8cm. After the target fish is captured, it is temporarily kept in an aquarium and oxygenated. In order to reduce the stress response of the fish, the test can only be started after the fish is temporarily kept for 24 hours. When the test fish needs to be transported during the test, use a fine net that causes less damage to the fish and a bucket with water to transport the fish to reduce the impact on the test fish. Test equipment: The water tank for the fish swimming ability test is a circular test water tank for fish swimming ability. The flow rate calibration before the test uses the LGY type II propeller flowmeter. During the test, the dissolved oxygen and temperature were measured using the DO200 dissolved oxygen meter from the American YSI company. The local air pressure value was input for dissolved oxygen calibration before use. The flow rate in the water tank was gradually increased by adjusting the motor operating frequency (f, Hz). The flow rate in the water tank was tested every time the motor frequency increased by a certain frequency. A standard curve was made and a linear fit was performed. The fitting equation for the flow rate-frequency curve of the test water tank is y=0.0474x-0.036, R 2 =0.999.

[0136] Swimming ability index: There are two types of indexes that characterize the swimming ability of fish, one is the current tendency characteristic, and the other is the ability to overcome the current. The current tendency characteristic refers to the tendency of fish to the water flow and the sensitivity of the induction. The ability to overcome the current is the ability of fish to overcome the water flow of a certain velocity. These two swimming ability indicators are usually important reference data in the design of fishways 2, and are also one of the key directions of fishway 2 and fish behavior research at home and abroad. Specifically, the current tendency characteristic of fish is mainly used for the design of the minimum flow velocity that occurs in the migration route; the speed of fish to overcome the flow is mainly used in the design of the flow velocity control of fishways 2.

[0137] Tidal characteristics: Tidal characteristics are generally measured by response flow speed. The response flow speed refers to the flow rate that can cause fish to respond to tidal flow. The response to tidal flow is usually indicated by the change in the direction of fish movement. In the design of fishways, the response flow speed is not only an important parameter for the design of the inlet fish attracting flow speed, but also a design reference for the minimum flow speed in fishways 2 and fish migration routes.

[0138] Flow-control ability: Based on the differences in the internal movement metabolism patterns of fish and the apparent movement duration, the flow-control ability of fish is mainly divided into three categories, which are expressed in terms of speed: sustained swimming speed, prolonged swimming speed and burst speed. The difference between these three speeds of some fish can be reflected by the change in the slope of the swimming time and speed relationship graph.

[0139] A. Sustained swimming speed: Fish can maintain sustained swimming mode for a long time without feeling tired, and the duration is usually calculated as >200 minutes. At this time, fish use aerobic metabolism to provide energy to slowly contract red muscle fibers, thereby propelling the fish forward.

[0140] B. Endurance swimming speed: The endurance swimming speed of fish is between the sustained swimming speed and the sprint swimming speed. It can usually be maintained for 20s to 200min and ends with fatigue. At this speed, the energy consumed by fish is obtained through both aerobic metabolism and anaerobic metabolism. Anaerobic metabolism provides higher energy, but it is easy to accumulate a large amount of lactic acid, which makes fish feel tired. Among them, the critical swimming speed that has been studied more is within the range of endurance swimming speed.

[0141] C. Burst swimming speed: Burst swimming speed is the maximum speed that fish can reach, and it is maintained for a very short time, usually <20s. At this speed, fish obtain greater energy through anaerobic metabolism, achieve short-term burst swimming speed, and also accumulate waste such as lactic acid. According to the different swimming time, burst swimming ability can be divided into burst swimming speed and sprint swimming speed. Among them, burst swimming speed refers to the maximum swimming speed that fish can reach in a very short time (<2s), which is usually used when hunting and emergency avoidance. Sprint swimming speed refers to the maximum swimming speed that fish can reach in a short time (<20s). Sprint swimming speed is an important parameter in fishway design. Generally, fish will slow down or speed up by adjusting the frequency and amplitude of their body and tail fin swings to maintain the acceleration as a gliding swimming method, which can reduce the energy consumed by fish.

[0142] Fish often use sustained swimming speed for exercise (e.g. migration), usually use endurance swimming speed in difficult areas, and use burst swimming speed when hunting and escaping. Sustained exercise of fish is considered to be a "marathon" aerobic metabolism exercise of fish. Its sustained swimming speed is the maximum speed at which fish can swim stably for 6 hours without exhaustion. Endurance swimming exercise is a swimming exercise that combines aerobic and anaerobic metabolism of fish. The duration of endurance swimming speed is generally 20s to 200min. The duration of endurance swimming speed is related to the type of fish, individual size, water temperature, and the period of burst swimming and sustained swimming.

[0143] Test content: In order to comprehensively study the swimming ability of fish, this project tests the fish's current-seeking characteristics and ability to overcome currents. The test indicators are: induced flow velocity, critical swimming speed, and aggressive swimming speed.

[0144] The test scheme is as follows: 1. Induction flow rate: The induction flow rate test generally uses the water flow rate corresponding to the direction of the fish to adjust the swimming direction as an indicator, including two test methods. The first test is for the group. More than 10 fish are placed in the tank, and the flow rate is gradually increased until half of the test fish turn to the upstream direction. At this time, the flow rate is the induced flow rate of the test fish group. The second test method is for individuals. The test fish is placed alone in the static water of the tank, and then the flow rate is gradually increased until the test fish turns to the upstream direction. At this time, the flow rate is the induced flow rate of the test fish individual. 2. Critical swimming speed: There are usually two test methods for measuring critical swimming speed: Fixed flow rate method: In the fixed flow rate test, the fish is placed in a constant flow rate, and the flow rate does not change during the entire experiment. First, let the fish adapt to the tank for a period of time, and then adjust the flow rate to a specific required flow rate. This flow rate increase must be completed within the specified time. This procedure must be repeated many times at different sub-maximum flow rates. In the test of fish swimming ability, in order to avoid differences caused by the influence of the individual environment and physiology. Fixed swimming speed tests all use a large number of fish of the same size and the same conditions, and require observation for a considerable period of time. Therefore, in recent years, the incremental flow rate method, which is less time-consuming and has a small sample size, has been mainly used for testing. Increasing flow rate method: Before starting the experiment, the fish's body length and weight are tested and the fish are placed in the swimming area of ​​the experimental device. The initial flow rate of the experimental device is set to 1bl / s (bl is the body length of the fish), the flow rate gradient is 1bl / s, and the time gradient is 15min. The dissolved oxygen and temperature are tested every 5 minutes. When the fish is fatigued (judgment criterion: the fish reaches the grid at the end of the swimming area and cannot swim), the fish is removed from the sealed area and its weight is tested. Since the fish is always swimming in the swimming area, it can be assumed that the fish's swimming speed is equal to the water flow speed. Critical swimming speed U crit For U crit =U p +(t f / t i )×U t , where: U p (bl / s) is the swimming speed of the fish during the entire time period, U t (bl / s) is the velocity gradient, t f (min) is the time it takes for the fish to accelerate to fatigue for the last time, t i (min) is the time gradient. Since the cross-sectional area of ​​the fish is smaller than 10% of the cross-sectional area of ​​the swimming area, the retention effect can be ignored, that is, there is no need to correct the critical swimming speed. The test time of the incremental flow rate method is relatively short, the method is highly controllable, and the number of fish required to obtain a statistically significant value is small, so the incremental flow rate method is selected to test the critical swimming speed. 3. Burst swimming speed: Since the burst swimming speed is maintained for a very short time and the reaction of fish is inconsistent, this embodiment uses the "increased flow rate method" with a time step of 20s to test the breakthrough speed index value. The incremental flow rate method test is the same as the critical speed test method, with a time step of 20s. The breakthrough swimming speed U breakthrough calculation formula is U breakthrough = Up + (tf / ti) × Ut, where: Where Up (bl / s) is the swimming speed of the fish during the entire time period that the fish can swim, Ut (bl / s) is the speed gradient, tf (min) is the time experienced by the fish when the last increase in speed reaches the fish fatigue, and ti (min) is the time gradient. Since the cross-sectional area of ​​the fish is less than 10% of the cross-sectional area of ​​the swimming zone, the retention effect can be ignored, i.e., there is no need to correct for the critical swimming speed.

[0145] Comprehensive evaluation of swimming speed: This test counts the critical swimming speed and burst swimming speed test values. If 50% of the tested fish can overcome a certain flow rate value, then this flow rate value is called the swimming speed index of this fish. Comprehensive evaluation of swimming ability: Sustained swimming speed range, 0-80% critical swimming speed; Endurance swimming speed range, 80% critical swimming speed to burst speed; Burst swimming speed range, burst speed to 10bl / s (body length / second). The test results, taking eel, sea bass, red-eyed trout and dace as examples, are shown in Table 2:

[0146] Table 2: Test results of the flow velocity, critical swimming speed and surging swimming speed of various fish species

[0147]

[0148] Eel: Figure 1 a. Figure 1 b and Figure 1As shown in Figure c, the half tolerance of the eel's critical swimming speed is 0.59m / s, and the half tolerance of the thrust speed is 0.73m / s. The upper limit of the sustained swimming speed is near 80% of the critical speed, so the boundary between the sustained swimming speed and the endurance swimming speed of the eel is near 0.48m / s. According to the swimming speed range, the thrust speed is the lower limit of the burst swimming speed, so the thrust speed of 0.73m / s is the boundary between the endurance swimming speed and the burst swimming speed. The upper limit of the burst swimming speed is 10bl / s.

[0149] Lappet: Figure 1 d. Figure 1 e and Figure 1 As shown in Figure 1, the half tolerance of the critical speed of the striped seabass is 1.14 m / s, and the half tolerance of the thrust speed is 1.37 m / s. The boundary between the sustained swimming speed and the endurance swimming speed of the striped seabass is around 0.91 m / s (1.14 m / s × 80%). The thrust speed is the lower limit of the burst swimming speed, and the thrust speed of 1.37 m / s is the boundary between the endurance swimming speed and the burst swimming speed. The upper limit of the burst swimming speed is 10 bl / s.

[0150] Red-eyed trout: Figure 1 g. Figure 1 h and Figure 1 As shown in Figure 1, the half tolerance of the critical speed of the red-eyed trout is 0.98 m / s, and the half tolerance of the thrust speed is 1.45 m / s. The boundary between the sustained swimming speed and the endurance swimming speed of the red-eyed trout is around 0.78 m / s (0.98 m / s × 80%). According to the swimming speed interval, the thrust speed is the lower limit of the burst swimming speed, and the thrust speed of 1.45 m / s is the boundary between the endurance swimming speed and the burst swimming speed. The upper limit of the burst swimming speed is 10 bl / s.

[0151] Ling Ru Figure 1 k. Figure 1 m and Figure 1 As shown in Figure 1, the half tolerance of the critical speed of the dace is 1.07 m / s, and the half tolerance of the burst speed is 1.55 m / s. The boundary between the sustained swimming speed and the endurance swimming speed of the dace is around 0.76 m / s (1.07 m / s × 80%). According to the swimming speed interval, the burst speed is the lower limit of the burst swimming speed, so the burst speed of 1.55 m / s is the boundary between the endurance swimming speed and the burst swimming speed. The upper limit of the burst swimming speed is 10 bl / s.

[0152] Swimming speed analysis: According to the test results of the swimming ability of the tested fish and the analysis of the swimming speed, see Table 3.

[0153] Table 3 Swimming ability test results and swimming speed analysis

[0154]

[0155] The swimming ability test results of the knife-clawed anchovy are used to compare the seven-threaded anchovy. Except for the striped sea bass, the test results of the fish passage objects are mostly within the fish passage specification range. However, since the striped sea bass is larger than other fish and has stronger swimming ability, the swimming ability of the striped sea bass does not constitute a restrictive condition. The main controlling condition for the fishway is reflected in the structural size.

[0156] 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.

[0157] 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.

[0158] 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.

[0159] 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:

[0160] 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.

[0161] 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.

[0162] 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.

[0163] 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.

[0164] 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.

[0165] 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.

[0166] 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.

[0167] 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 structural parameter calculation model 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 fishway flow rate, B is the width of the vertical seam 31; and h is the water depth.

[0168] 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 resting 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.

[0169] 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.

[0170] 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.

[0171] 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, 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.

[0172] Table 4 Fishway parameters

[0173] 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

[0174] 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.

[0175] 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.

[0176] 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.

[0177] 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 slit fish channel 23 at an elevation of 3.39m, and then the eels will use the vertical slit fish channel 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.

[0178] Fishway partial section model test

[0179] Research content: partial section model test of fishwayResearch content: a. Study the internal structure and flow pattern of the pool chamber; b. Observe the water level difference between the upstream and downstream of the adjacent pool chambers 30, the flow velocity, flow pattern and local water flow phenomenon through the fish gap; c. Measure the flow velocity distribution, flow pattern and local water flow phenomenon in the pool chamber 30; d. Study and determine the form of the energy dissipation structure (partition 32), the size of the pool chamber 30 and the vertical seam 31, etc. Form a recommended plan for the structure of the pool chamber 30.

[0180] Preparation of the local section physical model of the fishway project: Similarity conditions: According to the research content of the local section physical model of the fishway project, the local section physical model of the fishway project should be a normal model, and the model design is carried out according to the gravity similarity criterion, and the model is a normal model. Taking into account the scale of the fishway structure and the limitations of the model site, the geometric scale of the local section physical model of the fishway project is determined to be 1:4. The model should meet the geometric similarity, water flow movement similarity and dynamic similarity, and follow the Froude similarity criterion. The scales of each item are shown in Table 5.

[0181] Table 5 Calculation table of various scales of the local section physical model of the fishway project

[0182] Scale Plane scale Vertical scale Flow rate scale Flow rate scale Roughness scale formula <![CDATA[λ L ]]> <![CDATA[λ H ]]> <![CDATA[λ v =λ L 1 / 2 ]]> <![CDATA[λ Q =λ L 5 / 2 ]]> <![CDATA[λ n =λ L 1 / 6 ]]> Actual scale 4 4 2 32 1.26

[0183] In addition, the model water flow must be turbulent, that is, the model Reynolds number Rem = VR / v = 46875> 1000. In the formula, V is the water flow velocity, m / s; R is the hydraulic radius, m; ν is the water flow motion viscosity coefficient.

[0184] The scope of the local section model: The local section physical model of the fishway project is based on the preliminary design of the vertical slot fishway 23. In combination with the requirements and contents of the test research, the scope of the local model includes 10 pools 30 in the fishway, marked C1~C10, 11 groups of baffles 32, marked 1#~11# baffles 32, and guide plates 35. The upstream is connected to the flat channel, and the downstream is connected to the adjustable tail gate. The local model structure layout is shown in Figure 7 , which includes an upstream flat bottom section, a test slope section and a downstream flat bottom section which are connected in sequence.

[0185] Model making: During the process, the bottom slope of the fishway is controlled by the cross-section method and cast with cement; the partition 32 and the guide plate 35 are made of gray plastic board and wood board; the pile structure 22 is made of PVC pipe. In order to facilitate the observation of the flow state and fish migration characteristics in the pool chamber 30, the single side wall of the model pool chamber 30 is made of plexiglass as the observation section of the pool chamber 30. The roughness should meet the resistance similarity requirements. According to the design scheme of the vertical seam fishway 23, the design bottom slope of the pool chamber 30 is I=1.96%, the net width of the prototype pool chamber 30 is 3.0m, the length of the pool chamber 30 is 3.6m, the width of the partition 32 and the guide plate 35 are both 0.3m, and the end is rounded with a radius of R=0.15m, the width of the vertical seam 31 is 0.45m, the diversion angle is 30°, and the bottom pile structure 22 has a diameter of 0.15m and a height of 0.10m.

[0186] Experimental study on design scheme: According to the preliminary design scheme of vertical slot fishway 23, the bottom slope of chamber 30 is designed to be I=1.96%, corresponding to the low water level design conditions upstream and downstream of the fishway, the average low tide level at the estuary is -0.52m ~ the outlet operating water level is 8.0m, and the minimum water depth in chamber 30 is 1m. On the basis of the unchanged geometric scale of chamber 30, the volume of energy dissipation water body is the minimum value, which is used as the most unfavorable design condition for the fishway cross-section model test. During the test, the upstream flat water channel and the downstream overflow plate were used to control the upstream and downstream water levels to be constant. 12 water gauges were arranged along the model to measure the water level of chamber 30. The flow field of chamber 30 and vertical slot 31 was collected at a single point using an acoustic Doppler flow meter. Figure 8 As shown, the water level difference of chamber 30: the water depth of the inlet and outlet is controlled to be 1m, and the water level distribution of chamber 30 along the way is measured by a water gauge to consider the influence of the inlet and outlet water flow stability. The water level characteristic values ​​of the typical chamber 30 in the middle of the model are shown in Table 6.

[0187] Table 6 Water level characteristic values

[0188] serial number C4 C5 C6 C7 C8 Pool room 30 water level (m) 1.44 1.38 1.31 1.25 1.18 Water level difference between 30 pool rooms / 0.06 0.07 0.06 0.07 Water depth in the pool room 30m 0.98 0.99 0.99 1 1

[0189] It can be seen from the above table that the water surface line of chamber 30 is basically parallel to the bottom slope, the average water depth of typical chambers 30C4~C8 is 0.99m on average for each chamber 30 in the local model, and the average water level difference of each level of chambers 30 is 0.065m.

[0190] Flow velocity distribution of vertical slit 31: Flow velocity of 5#~7# vertical slit 31 was measured. Four measuring points at different positions were arranged from top to bottom along the water depth on the center line of each vertical slit 31 [0.8H, 0.6H, 0.4H, 0.2H, 0.12H, H is the water depth value of vertical slit 31]. The flow velocity of the measuring points of the vertical slit 31 passing the fish is summarized in Table 7. The flow velocity distribution of vertical slit 31 is as follows Fig. 9 .

[0191] Table 7 Flow velocity at each measuring point vertically through the fish vertical slit 31, m / s;

[0192]

[0193] By testing the swimming ability of the target fish species, it was found that the flow velocity distribution of the vertical slot 31 in the vertical slot fishway 23 was 0.54-1.37 m / s, and the average flow velocity was 1.0 m / s.

[0194] It can be seen from the above table that the average flow velocity of the vertical seam 31 under the design scheme is 1.11m / s, and the flow velocity range of the measuring point is between 0.78 and 1.36m / s, which basically meets the value range requirement of 0.54 to 1.37m / s. The average flow velocity exceeds the average flow velocity control index of 1m / s.

[0195] Calculate the velocity coefficient of the partition 32 according to the following formula And the power dissipation E of 30 units of water in the pool room: E = ρg△hQ / V, v is the average flow velocity of the vertical seam 31; △h is the average water level difference of the partition 32; Q is the average flow rate of the fishway; V is the water volume of the pool chamber 30 (m 3 ) According to calculation, the flow rate of vertical slot fishway 23 is Q = 0.50m 3 / s, velocity coefficient of partition 32 Meets the requirements; unit water power dissipation E = 29.43W / m 3 <200W / m 3 , that is, the turbulence intensity of the water flow in the pool chamber 30 is small enough, and the size of the pool chamber 30 meets the power dissipation requirements per unit water body.

[0196] Flow field distribution in the pool chamber 30: Taking the C6 pool chamber 30 as an example, the C6 pool chamber 30 is selected to measure the surface flow field distribution. Five measuring lines marked N1 to N5 are set along the width of the pool chamber 30. Each measuring line has 7 measuring points marked L1 to L7 along the length of the pool chamber 30, totaling 35. The measuring points are distributed as follows: Fig.10 .

[0197] like Fig.11 As shown, it can be seen from the schematic diagram of the flow field distribution of the pool chamber 30 in the design scheme that, driven by the water level difference between the upstream and downstream of the vertical slit 31, the water flows around the partition 32 and passes through the vertical slit 31, and enters the pool chamber 30 in the form of a jet to form the main flow of the pool chamber 30. The main flow of the pool chamber 30 is continuous and smooth, that is, the curvature is small. The rear side of the partition 32 forms a rear circulation flow, and the rear side of the guide plate 35 does not form a complete recirculation zone.

[0198] The flow velocity at the measuring point in the pool chamber 30 is shown in Table 8. The flow velocity distribution along the width of the pool chamber 30 along each measuring line [N1~N5] is as follows Fig.12 .

[0199] Table 8 Measurement points and flow velocity ∑V (m / s) in chamber 30

[0200]

[0201] like Fig.12 As shown in the figure, it can be seen from the distribution of Vx along the path that the near-side wall measurement lines N1 and N5 are negative in the front section of the pool chamber 30, corresponding to the backflow behind the partition 32 and the guide plate 35. The negative value range of Vx of the N1 measurement line (0.79≤x≤3.04m) and the value are larger than those of the N5 measurement line (-0.22≤Vx≤-0.02m / s), that is, the backflow behind the partition 32 has a larger impact range and intensity; from the distribution of ∑V along the path in the figure, it can be seen that the mainstream in the pool chamber 30 is not fully diffused, the flow velocity is unevenly distributed along the cross-sectional width, and the maximum flow velocity is concentrated at the positions of the two measurement lines N3 and N4, and the minimum value of the mainstream ∑V=0.81m / s. The ratio of the minimum value of the mainstream of the pool chamber 30 to the average flow velocity of the vertical seam 31 reflects the energy dissipation rate of the pool chamber 30. The energy dissipation rate of the pool chamber 30 in the design scheme is about 27%.

[0202] The near-wall area provides a low velocity area to ensure that the target fish can rest, but in order to prevent small fish from getting lost and delaying their upstreaming time, a certain amount of backflow is required to meet the energy dissipation requirements, but the backflow cannot be too intense and the range cannot be too large. Definition L c is the maximum length of the recirculation zone, B c is the maximum width of the reflow zone, v cmax is the maximum flow velocity in the recirculation zone, L is the length of the pool chamber 30, B is the width of the pool chamber 30, and the quantitative parameters of the recirculation zone are shown in Table 9.

[0203] Table 9 Reflow zone parameters

[0204] Recirculation zone location <![CDATA[L c / L]]> <![CDATA[B c / B]]> <![CDATA[L c / B c ]]> <![CDATA[L c B c / LB]]> <![CDATA[v cmax (m / s)]]> After partition 32 0.83 0.50 2.00 0.42 0.34 Guide plate 35 rear / / / / /

[0205] L c B c / LB can be used to define the impact range of the reflow zone, from Fig.11 As can be seen from Table 9, the recirculation area behind the guide plate 35 is suppressed under the design scheme, and a stable and complete recirculation is not formed. The recirculation area behind the partition plate 32 has a large influence range, and L c B c / LB=0.42,intensity v cmax =0.34m / s.

[0206] In summary: the preliminary design of the vertical slot fishway 23, the section of the pool chamber 30 is a rectangular section, the bottom slope of the pool chamber 30 is I = 1.96%, the length of the pool chamber 30 is 3.6m, the thickness of the partition 32 and the guide plate 35 are both 0.3m, the net width of the pool chamber 30 is 3.0m, the ends of the partition 32 and the guide plate 35 are not provided with piers, and are rounded by a semicircular arc with a radius of 0.15m, the width of the fish vertical slot 31 is 0.45m, the diversion angle is 30°, and the bottom is provided with a pile structure 22 with a diameter of 15cm and a height of 10cm, the centerline spacing of the piles is 45cm, and the two rows are staggered. By establishing a local model with a geometric scale of 1:4 to demonstrate the water flow conditions of the design scheme, the following conclusions are obtained:

[0207] The water surface line along the pool chamber 30 is basically parallel to the bottom slope, the average water level difference of the pool chamber 30 is 0.065m, the average flow velocity of the vertical seam 31 is 1.11m / s, and the flow velocity at the measuring points is distributed between 0.97 and 1.36m / s, which basically meets the value range requirement of 0.54 to 1.37m / s. The average flow velocity exceeds the average flow velocity control index of 1m / s.

[0208] The flow rate of vertical slot fishway 23 is about 0.50m 3 / s, velocity coefficient of partition 32 Unit water power dissipation E = 29.43 W / m 3 The turbulence intensity of the water flow in the pool chamber 30 is small enough, and the size of the pool chamber 30 is reasonable to meet the power dissipation requirements per unit water body.

[0209] Driven by the water level difference between chambers 30, the water flow bypasses the pier of partition 32 and enters chamber 30 through the fish-passing vertical slit 31. The mainstream in chamber 30 has a small curvature along the way and is not sufficiently diffused along the width of chamber 30. The maximum flow velocity is concentrated on the N3 and N4 measuring lines along the way, and the minimum value of the mainstream is 0.81 m / s. The average flow velocity in chamber 30 is 0.50 m / s, which meets the recommended average flow velocity range of 0.24 to 0.67 m / s for chamber 30.

[0210] There is no obvious deflection and diffusion of the mainstream in the pool chamber 30. The development of the backflow behind the guide plate 35 is suppressed, and a complete and stable backflow zone is not formed. A large-scale backflow zone is formed behind the partition 32 under the shear effect of the mainstream. cBc / LB=0.42, maximum reflux intensity v cmax =0.34m / s. A large reflux range can easily cause small fish to lose their way.

[0211] In summary, under the design scheme, the scale of the pool chamber 30, the width of the vertical seam 31, and the main bottom slope are basically reasonable and meet the upstream requirements of the target fish; the diversion angle is small, so that the mainstream injected into the pool chamber 30 through the vertical seam 31 does not undergo obvious deflection and energy dissipation in the pool chamber 30, which is about 27%. The average flow velocity in the vertical seam 31 exceeds the design recommended value. At the same time, a large-scale reflux area is formed on the rear side of the partition 32, which can easily cause small fish to lose their way and delay the upstream time. It is necessary to adjust the flow state in the pool chamber 30.

[0212] Experimental study on optimization scheme

[0213] Overview of the optimization scheme: After the design scheme test, the diversion angle of 30° is too small, which is the main reason why the mainstream is almost vertically injected into the lower chamber 30 and the diffusion is insufficient in the chamber 30, and the influence range of the single-sided recirculation area behind the partition 32 is too large. Therefore, the optimization idea of ​​increasing the diversion angle to promote the deflection of the mainstream in the chamber 30 is adopted. The diversion angle is optimized, and the scale of the chamber 30, the width of the vertical seam 31, the bottom slope of the chamber 30 and the arrangement of the pile structure 22 remain unchanged, and a series of optimization test studies are carried out. Based on the design scheme of 30° diversion angle, it is increased to 45° and 50° respectively to form 45° and 50° single-sided vertical seam fishway 23 schemes, and a 45° opposite-side vertical seam fishway 23 scheme is added for synchronous comparative demonstration. The characteristic structural parameters of the optimization scheme and the structure of the chamber 30 are shown in Table 10, Fig.13 .

[0214] Table 10 Characteristic structural parameters of the series of optimization schemes and vertical seam flow rates of different schemes

[0215]

[0216] Comparative analysis of schemes: Same-side vertical slot fishway scheme: In view of the unfavorable water flow conditions in the pool chamber 30, such as the average flow velocity of the vertical slot 31 exceeding the design requirements and no obvious deflection of the mainstream in the pool chamber 30, a comparative analysis was conducted on the three sets of design schemes of the single-side vertical slot fishway 23, Run1 and Run2.

[0217] The flow rates of the vertical slot 31 of the three groups of vertical slot fishway 23 on the same side are shown in Table 10. Fig.14 . Compared with the design scheme, the water flow velocity in the vertical seam 31 decreases after the diversion angle increases. Among them, the average flow velocity of the vertical seam 31 in Run1 decreases more significantly, that is, when the diversion angle is adjusted to 45°, the average flow velocity of the vertical seam 31 drops from 1.11m / s in the design scheme to 1.01m / s, and the flow velocity range is 0.99~1.06m / s, which meets the design recommended flow velocity requirements. When the diversion angle continues to increase to 50°, the flow velocity of the vertical seam 31 in the Run2 scheme increases compared with the Run1 scheme. The average flow velocity of the vertical seam 31 is 1.05m / s, and the flow velocity is distributed in the range of 1~1.16m / s. At the same time, it can be seen from the vertical distribution of the flow velocity that the vertical distribution of the flow velocity in the vertical seam 31 is more uniform after the diversion angle increases.

[0218] Different-side vertical slit fishway 23 scheme: By comparing the three groups of single-side vertical slit fishway 23 schemes with different diversion angles, it can be seen that when the diversion angle is 45°, the flow velocity in the vertical slit 31 decays most significantly, and the average flow velocity is 1.01m / s, which meets the flow velocity recommendations proposed in the design stage. Therefore, based on this diversion angle, in view of the design problems exposed by the design scheme, such as insufficient mainstream deflection and the flow state in the pool chamber 30 being unfavorable for fish to swim upstream, the water flow conditions of the three groups of schemes are compared: the design scheme, the single-side vertical slit fishway 23Run1 with a diversion angle of 45°, and the double-side vertical slit fishway 23Run3 with a diversion angle of 45°. The flow velocity distribution of the vertical slit 31 of different schemes is shown in Table 11, Fig.15 The typical flow field distribution under the three schemes is as follows: Fig.16 .

[0219] As can be seen from the chart, for the same diversion angle, the arrangement of the vertical seams 31 on the opposite sides has an adverse effect on the water flow energy dissipation. Under the Run3 scheme, the average flow velocity of the vertical seams 31 reaches 1.23m / s, which is 23% higher than the average flow velocity of 1.0m / s recommended by the design. Fig.16 It can be seen that the mainstream in the pool chamber 30 of both Run1 and Run3 schemes is significantly deflected, such as Fig.17As shown, compared with the design scheme, the mainstream in the pool chamber 30 attenuates significantly along the way, and the attenuation rate increases to about 50%. The single-sided vertical slit 31 scheme of Run1 forms a slightly curved S-shaped mainstream in the single-stage pool chamber 30, and forms a complete recirculation zone behind the baffle 32 and the recirculation zone behind the guide plate 35 on both sides of the mainstream. The mainstream in the pool chamber 30 shows a trend of first decreasing and then increasing, with a minimum value of 0.51m / s in the middle and lower section of the pool chamber 30 (L6 survey line); the opposite-side vertical slit 31 scheme (Run3) forms an S-shaped mainstream in two consecutive pool chambers 30, and a recirculation zone behind the baffle 32 is formed in the single-stage pool chamber 30. The mainstream in the pool chamber 30 decreases along the way, and the mainstream minimum value of 0.60m / s appears near the lower vertical slit 31 at the downstream end of the pool chamber 30.

[0220] Table 11 Flow rate of vertical seam 31 in different schemes

[0221]

[0222]

[0223] Summary of optimization scheme: In view of the water flow conditions that are not conducive to fish upstreaming, such as the average flow velocity of the vertical slit 31 slightly exceeding the design recommended value shown in the design scheme test, insufficient mainstream deflection in the pool chamber 30, and obvious development of unilateral backflow behind the partition 32, the optimization idea is to increase the diversion angle to promote the mainstream deflection of the pool chamber 30. The three groups of optimization schemes of the single-sided vertical slit fishway 23 scheme with diversion angles of 45° and 50° and the opposite-side vertical slit fishway 23 with a diversion angle of 45° are compared and demonstrated simultaneously. Combining the test results of the three groups of vertical slit fishway 23 optimization schemes, it can be seen that with the increase of the diversion angle, the mainstream in the pool chamber 30 is significantly deflected compared with the design scheme (30° diversion angle), and the mainstream attenuation rate in the pool chamber 30 increases from 23% to about 50%. The single-sided vertical slot fishway 23 with a diversion angle of 45°, the flow velocity of the vertical slot 31 and the distribution characteristics of the main stream in the chamber 30 along the way are more reasonable than other schemes. The average flow velocity of the vertical slot 31 is reduced from 1.11m / s in the design scheme to 1.01m / s, which meets the design recommended flow velocity requirements of the vertical slot 31. At the same time, the main stream in the single-stage chamber 30 forms a slightly curved S-shaped curve, and a complete and stable recirculation zone is formed on both sides of the main stream. Therefore, the single-sided vertical slot fishway 23 scheme with a diversion angle of 45°, chamber 30 scale, vertical slot 31 width, chamber 30 bottom slope and pile structure 22 layout remaining unchanged from the design scheme is recommended as the cross-section model of the fishway at the hub 1.

[0224] Test results of the recommended scheme: Scheme overview: The recommended scheme pool chamber 30 is designed with a bottom slope of I = 1.96%, the net width of the prototype pool chamber 30 is 3.0m, the length of the pool chamber 30 is 3.6m, the width of the partition 32 and the guide plate 35 are both 0.3m, and the ends are rounded with a radius of R = 0.15m, the vertical seam 31 is 0.45m wide, the diversion angle is 45°, the bottom pile structure 22 has a diameter of 0.15m and a height of 0.10m, and the pool chamber 30 is arranged as follows Fig.18. Water level difference in pool room 30: Fig.19 As shown, the water depth at the inlet and outlet is controlled to be 1m. The water level distribution of 30 chambers along the recommended scheme is measured by water gauge. Considering the influence of the water flow stability at the inlet and outlet, the water level characteristic values ​​of 30 chambers in the middle of the model are shown in Table 5.4-4.

[0225] Table 5.4-4 Water level characteristic values

[0226] serial number C4 C5 C6 C7 C8 Pool room 30 water level (m) 1.47 1.4 1.33 1.26 1.19 Water level difference between 30 pool rooms / 0.07 0.07 0.07 0.07 Water depth in the pool room 30m 1 1 1 1.01 1.01

[0227] It can be seen from the above table that the water surface line of chamber 30 is basically parallel to the bottom slope. The water levels of the upstream inlet and downstream outlet of the control model are 1.71m and 1.00m respectively, that is, the water depth of the flat slope section is maintained at 1.00m. The average water depth of chambers C4 to C8 is 1.00m, and the average water level difference of chambers 30 at each level is 0.07m.

[0228] Flow velocity distribution of vertical seam 31: Flow velocity of 5#~7# vertical seams 31 was measured. Four measuring points were arranged from top to bottom along the water depth on the center line of each vertical seam 31, which were 0.8H, 0.6H, 0.4H, and 0.2H, respectively. H is the water depth value at the vertical seam 31. The flow velocity of the measuring points of the vertical seam 31 passing the fish is summarized in Table 12. The flow velocity distribution of the vertical seam 31 is as follows: Fig. 20 .

[0229] Table 12 Flow velocity at each measuring point in the vertical slit 31 (m / s)

[0230]

[0231] It can be seen from the chart that under the recommended scheme, the average flow velocity of the vertical joint 31 is 1.01m / s, and the average flow velocity of the measuring points is distributed between 0.99 and 1.06m / s, which basically meets the requirements of the average flow velocity of the vertical joint 31 being 1m / s and the flow velocity distribution being in the range of 0.54 to 1.37m / s.

[0232] The recommended solution is vertical slot fishway 23 flow rate Q = 0.45m 3 / s, calculate the velocity coefficient of partition 32 The power dissipation of 30 units of water in the pool is E = 28.61 W / m 3 <200W / m 3 , the size of pool chamber 30 meets the power dissipation requirements per unit water body.

[0233] Flow field distribution in the pool chamber 30: Select a typical pool chamber 30 to measure its flow field distribution, and the measurement point arrangement is the same as the design scheme. The recommended solution pool chamber 30 flow field distribution is shown as follows Fig.21As can be seen from the figure, driven by the water level difference between the upstream and downstream of the vertical slit 31, the water flows around the baffle 32 and passes through the vertical slit 31 to enter the pool chamber 30 in the form of a jet to form the mainstream of the pool chamber 30. The mainstream presents an obvious S-shaped continuous curve in the pool chamber 30, and a complete and stable recirculation zone is formed behind the baffle 32 and the guide plate 35. The flow velocities of the measuring points in the pool chamber 30 of the recommended solution are shown in Table 13. The minimum flow velocity of the mainstream occurs at the measuring point L6, ∑V=0.51m / s, which is significantly lower than the minimum flow velocity of the mainstream in the design solution, that is, as the curvature of the mainstream entering the pool chamber 30 increases, the degree of mainstream attenuation increases.

[0234] Table 13 Measurement points and flow rate ∑Vm / s in chamber 30

[0235]

[0236] The flow velocity distribution along the 5 measuring lines [N1~N5] with a width of 30 in the pool is as follows Fig. 22 As shown. From the distribution of Vx along the figure, it can be seen that the near-side wall measurement lines N1 and N5 are negative in the front section of the pool chamber 30, corresponding to the recirculation area behind the partition 32 and the guide plate 35. The negative value range of Vx of the N1 measurement line is 1.24≤x≤2.14m, and the value is -0.13≤Vx≤-0.01m / s. The negative value range of Vx of the N5 measurement line is 1.24≤x≤3.04m, and the value is -0.22≤Vx≤-0.04m / s; From the distribution of ∑V along the figure, it can be seen that the mainstream in the pool chamber 30 is concentrated at the positions of the two measurement lines N3 and N4, and the flow velocity distribution in the pool chamber 30 is more uniform than the design scheme, that is, the mainstream is effectively dissipated through the vertical slit 31 jet. The quantitative parameters of the recirculation zone of the recommended scheme are shown in Table 14.

[0237] Table 14 Reflow zone parameters

[0238] Recirculation zone location <![CDATA[L c / L]]> <![CDATA[B c / B]]> <![CDATA[L c / B c ]]> <![CDATA[L c B c / LB]]> <![CDATA[v cmax (m / s)]]> After partition 32 0.38 0.33 1.36 0.12 0.18 Guide plate 35 rear 0.5 0.33 1.82 0.17 0.24

[0239] The influence range L of the backflow area behind the partition 32 c B c / LB=0.12, reflux intensity v cmax =0.18m / s, the influence range of the recirculation area behind the guide plate 35 is L c B c / LB=0.17, reflux intensity v cmax =0.24m / s. Compared with the design scheme, the backflow in the pool chamber 30 of the recommended scheme is redistributed to form a stable and complete backflow behind the guide plate 35, and the influence range of the backflow behind the partition 32 is reduced from 0.42 to 0.12, and the intensity is attenuated from 0.34m / s to 0.24m / s.

[0240] Summary of recommended solutions: The diversion angle 30° is too small as exposed in the design solution. The mainstream is almost vertically injected into the lower chamber 30, and the mainstream diffusion in the chamber 30 is insufficient. The unilateral backflow range behind the baffle 32 is too large, which makes it easy for the target fish to swim upstream, creating unfavorable water flow conditions in the chamber 30. The diversion angle is optimized. Hub 1 recommends keeping the scale of the chamber 30, the width of the vertical seam 31 and the bottom slope of the chamber 30 unchanged, increasing the diversion angle to 45°, promoting the mainstream deflection in the chamber 30, increasing the mainstream energy dissipation to form the optimized water flow structure of the chamber 30. The water flow conditions are demonstrated through a local model with a geometric scale of 1:4, and the following conclusions are obtained:

[0241] The water surface line along the pool chamber 30 is basically parallel to the bottom slope, 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 vertical line of the flow velocity is evenly distributed from the top of the pile structure 22 to the free water surface. The flow velocity of the vertical seam 31 is distributed between 0.99 and 1.06m / s, and the flow velocity of the vertical seam 31 passing fish meets the average flow velocity of 1m / s, and the flow velocity distribution ranges from 0.54 to 1.37m / s.

[0242] The flow rate coefficient of vertical seam 31 type baffle 32 is φ = 0.86, and the power dissipation per unit water in chamber 30 is E = 28.61 W / m 3 <200W / m 3 , the size of the pool chamber 30 meets the power dissipation requirements of the unit water body; on the basis of the unchanged size and bottom design of the pool chamber 30, the structure of the vertical seam 31, the partition 32 and the guide plate 35 is optimized, and the flow rate coefficient Reduced, corresponding to the design water depth of 1m, the flow rate of vertical joint 31 is about 0.45m 3 / s, which is about 7% lower than the design solution.

[0243] Under the recommended scheme, the water flow is driven by the water level difference between the chambers 30, bypasses the baffle 32 pier, and enters the chamber 30 through the fish-passing vertical slit 31. The mainstream in the chamber 30 is continuous, clear and S-shaped. After entering the chamber 30, the mainstream is effectively diffused. The average flow velocity in the chamber 30 is 0.37 m / s, which meets the average flow velocity range of 0.24 to 0.67 m / s in the chamber 30, and the mainstream flow velocity is ≥ 0.51 m / s.

[0244] The curvature of the mainstream in the pool chamber 30 increases, and a complete and stable reflux zone with a considerable influence range and strength is formed behind the partition 32 and the guide plate 35. The influence range of the reflux zones on both sides is 0.12-0.17, and the reflux intensity range is 0.18-0.24 m / s. A low flow velocity zone is created near the wall to ensure that the target fish can rest while preventing small fish from getting lost and delaying their upstreaming time.

[0245] The single-side vertical slot fishway 23 at the hub 1 has a rectangular section of the pool 30, a bottom slope of the pool 30 of I = 1.96%, a length of 3.6m, a thickness of 0.3m for the partition 32 and the guide plate 35, a net width of 3.0m, a width of 0.45m for the fish vertical slot 31, and a pile structure 22 with a diameter of 15cm and a height of 10cm at the bottom, a pile centerline spacing of 45cm, and two rows of staggered arrangements. By establishing a local cross-section model of the fishway with a geometric scale of 1:4, the rationality of the structure of the pool 30 and the partition 32 and the water flow conditions are evaluated, and an optimization study is conducted, and the following conclusions are obtained:

[0246] Under the design scheme, the pool chamber 30 scale, vertical seam 31 width, and main bottom slope design are basically reasonable, meeting the target fish's upstream requirements; the fishway flow rate is about 0.50m 3 / s, velocity coefficient of partition 32 The diversion angle is small, so that the mainstream injected into the pool chamber 30 through the vertical slit 31 does not have obvious deflection and energy dissipation in the pool chamber 30. The average flow velocity of the vertical slit 31 is 1.11m / s. After entering the pool chamber 30, the maximum flow velocity is concentrated along the N3 and N4 measuring lines, and the minimum value of the mainstream is 0.81m / s. At the same time, the development of the backflow behind the guide plate 35 is suppressed, and a complete and stable backflow zone is not formed. Under the action of the mainstream shear, a large-scale backflow zone is formed behind the partition 32, L c B c / LB=0.42, which may easily cause small fish to lose their way and delay their upstreaming time. Therefore, the flow pattern in the pool chamber 30 needs to be adjusted.

[0247] The small value of the diversion angle is the main reason why the water flow conditions in the vertical seam 31 and the pool chamber 30 do not meet the requirements of fish upstream; therefore, in order to promote the deflection of the mainstream in the pool chamber 30 and increase the energy dissipation of the mainstream, the diversion angle is adjusted to optimize the water flow structure of the pool chamber 30; the recommended solution is to keep 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 increase the diversion angle to 45°.

[0248] Under the recommended solution, 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, the flow velocity distribution of the vertical seam 31 is between 0.99 and 1.06m / s, and the flow velocity of the fish-passing vertical seam 31 meets the requirements of an average flow velocity of 1m / s and a flow velocity distribution range of 0.54 to 1.37m / s. On the basis of the unchanged size and bottom design of the pool chamber 30, the flow velocity coefficient is has decreased, For a design water depth of 1m, the flow rate of vertical joint 31 is about 0.45m 3 / s, which is about 7% lower than the design. The mainstream in the pool chamber 30 is continuous, clear and S-shaped. After entering the pool chamber 30, the mainstream is effectively diffused. The average flow velocity in the pool chamber 30 is 0.37m / s, which meets the average flow velocity range of 0.24-0.67m / s in the pool chamber 30, and the mainstream flow velocity is ≥0.51m / s. The curvature of the mainstream in the pool chamber 30 is increased, and a complete and stable recirculation zone with a considerable influence range and strength is formed behind the partition 32 and the guide plate 35. The influence range of the recirculation zones on both sides is 0.12-0.17, and the recirculation strength range is 0.18-0.24m / s. A low flow velocity zone is created near the wall to ensure that the target fish can rest while preventing small fish from getting lost and delaying the upstream time.

[0249] Overall model test of fishway: The overall model test of fishway mainly carries out the following research on the vertical slot fishway 23: a. Under the typical operating water level conditions upstream and downstream of the fishway, the flow pattern of water inlet and outlet of the designed fishway and the conditions for fish entering and leaving; b. Under different operating water level conditions during the fish passage period, the flow rate, water surface along the way, flow velocity changes of the designed fishway, and the flow velocity and flow pattern of the fish pond and rest pool 36; c. Propose suggestions for optimizing the type, scale and plane layout of the fishway inlet and outlet.

[0250] Design and production of the overall model of the fishway: Similarity conditions: The overall model of the fishway is designed as a normal model, and the overall model of the fishway is designed according to the gravity similarity criterion. Taking into account the structural scale of the fishway and the limitations of the model site, the geometric scale of the overall model of the fishway is determined to be 1:15. The model should meet the requirements of geometric similarity, water flow movement similarity and dynamic similarity. The scales of each item are shown in Table 15.

[0251] Table 15 Calculation table of scales of various items of fishway overall model

[0252] Scale Plane scale Vertical scale Flow rate scale Flow rate scale Roughness scale formula <![CDATA[λ L ]]> <![CDATA[λ H ]]> <![CDATA[λ v =λ L 1 / 2 ]]> <![CDATA[λ Q =λ L 5 / 2 ]]> <![CDATA[λ n =λ L 1 / 6 ]]> Actual scale 15 15 3.87 871 1.57

[0253] The model water flow is turbulent, and the model Reynolds number Re m =5230>1000, V: water flow velocity; R: hydraulic radius; ν: water flow viscosity coefficient.

[0254] Model making: The overall model making of the fishway is based on the hub plan layout provided by the design unit, the plant operation layer plan layout, the plant section, the project area topographic map, the fishway plan layout and the pool chamber 30 structure diagram after the cross-section model optimization. In combination with the design requirements and test content, the model simulates the original river section length of about 450m, including 200m upstream of the dam axis and 250m below the dam axis. It simulates two units, the fishway inlet, the entire trough body and the outlet, etc. The model is 30m long and 5.5m wide. In order to ensure that the natural terrain can be accurately reproduced on the model and ensure the accuracy of model making, the plane lofting adopts the plane wire control system, and the plane position error is controlled within ±5mm; the terrain is made by the cross-section method, and the average section spacing is about 90cm, which is basically perpendicular to the main river channel, and the terrain elevation error is within ±0.5mm. The fishway trough body and partition 32 are made of plastic plates. See the model layout. Fig.23 .

[0255] Design scheme test study: Overall model design scheme of fishway Design scheme overview: Plan layout: The fishway is arranged on the left side of the power station 27, and the inlet is arranged about 30m downstream of the power station 27, using the tail water of the power station 27 to attract fish. After the inlet, the fishway meanders upstream, with an axis length of about 485m, during which 120 pools 30 and 4 rest pools 36 are arranged. The rest pools 36 are arranged at 3 bends and the fishway flood gates, and each rest pool 36 is 6.6m long. The outlet is arranged about 150m upstream of the dam. The overall layout of the fishway is shown in Fig.23 . Pool chamber 30 plane structure: In the overall model design scheme test, the structural dimensions of pool chamber 30 are optimized using the cross-section model, that is, the net width of pool chamber 30 is 3.0m, the length is 3.6m, the partition 32 is 1.83m long, the guide plate 35 is 0.95m long, the vertical seam 31 is 0.45m wide, the diversion angle is 45°, and the bottom slope of pool chamber 30 is 1:51.02. The plane structural dimensions of pool chamber 30 are shown in Fig.24 , unit: cm. Test conditions: As shown in Table 16, according to the design operating water levels of the fishway upstream and downstream, the model selected 6 typical combined conditions for testing, including the highest and lowest operating water levels upstream, the lowest operating water level downstream [water depth of the fishway inlet 1.0m], the inlet water depth 1.7m [consistent with the outlet water depth at the highest water level upstream], and the highest operating water level [water depth of the fishway inlet 3.36m]. The test conditions are shown in Table 17.

[0256] Table 16 Fishway design operating water level

[0257] Design operating water level Maximum water level (m) Minimum water level (m) Water level fluctuation (m) Upstream 8.7 8 0.7 Downstream 1.84 -0.52 2.36

[0258] Table 17 Model test conditions

[0259]

[0260] Analysis of test results: Water level along the fishway: The changes in water level along the fishway under various working conditions are shown in Fig.25 In order to facilitate the analysis of the hydraulic characteristics along the fishway, the four rest pools set up in the fishway are numbered from 1# rest pool to 4# rest pool in the direction from the downstream fishway entrance to the upstream fishway entrance.

[0261] Condition 1: The normal water level of the upstream reservoir is 8.7m (the highest operating water level of the fishway upstream), and the water level below the dam (fishway inlet) is the lowest operating water level of the fishway design -0.52m. The water depth of the fishway outlet is 1.7m, and the water depth of the inlet is 1.0m. From the water surface line along the way, the water depth of the 30 chambers above the 2# rest pool 36 is about 1.7m, and the water level difference between adjacent chambers 30 is basically the same, about 0.07m, which is consistent with the design value. The chambers 30 below the 2# rest pool 36 are significantly affected by the downstream water level, the water depth decreases along the way, and the height difference between the 30 chambers gradually increases. The average height difference between the 7 chambers 30 at the downstream reaches 0.13m. Condition 2: The normal water level of the upstream reservoir is 8.7m (the highest operating water level of the fishway upstream), and the water level below the dam (fishway inlet) is 0.18m. Under this condition, the water depth of the fishway inlet and outlet is 1.7m, the water surface line of each chamber 30 along the fishway does not fluctuate much, the water surface gradient is basically consistent with the bottom slope of the fishway, the water depth in each chamber 30 is about 1.7m, and the water level difference between the chambers 30 is about 0.07m, which is consistent with the design value. Condition 3: The normal water level of the upstream reservoir is 8.7m (the highest operating water level of the fishway upstream), and the water level below the dam is 1.84m (the highest operating water level of the fishway downstream). The water depth of the fishway outlet is 1.7m, and the water depth of the inlet is 3.36m. From the perspective of the water surface line along the way, the water depth of the 30 chambers upstream of the 3# rest pool 36 is about 1.7m, and the water level difference between the 30 chambers is about 0.07m; the chambers 30 downstream of the 3# rest pool 36 are affected by the inlet water level, the water surface line gradient along the way decreases, the water depth of each chamber 30 gradually decreases, and the drop between the 30 chambers gradually decreases. The average drop between the 7 chambers 30 downstream is only 0.02m. Condition 4: The dead water level of the upstream reservoir is 8.0m (the lowest operating water level upstream of the fishway), and the water level below the dam (fishway inlet) is the lowest operating water level of the fishway design -0.52m. Under this condition, the water depth of the fishway inlet and outlet is 1.0m, the water surface line along the fishway does not fluctuate much, the water surface gradient is basically consistent with the bottom slope of the fishway, the water depth in each chamber 30 is about 1.0m, and the water level difference between the 30 chambers is about 0.07m, which is consistent with the design value. Condition 5: The dead water level of the upstream reservoir is 8.0m (the lowest operating water level upstream of the fishway), and the water level below the dam (the fishway inlet) is 0.18m. The water depth at the fishway outlet is 1.0m, and the water depth at the inlet is 1.7m. From the perspective of the water surface line along the way, the water depth of each room upstream of the 3# rest pool 36 is about 1.0m, and the water level difference between the 30 rooms is about 0.07m; the water level of each room 30 downstream of the 3# rest pool 36 is affected by the downstream water level, the water surface line gradient along the way decreases, the water depth of each room 30 gradually decreases, and the drop between the 30 rooms gradually decreases. The average drop between the 7 rooms 30 downstream is only 0.03m. Condition 6: The dead water level of the upstream reservoir is 8.0m (the lowest operating water level upstream of the fishway), and the water level below the dam is 1.84m (the highest operating water level downstream of the fishway). The water depth at the fishway outlet is 1.0m, and the water depth at the inlet is 3.36m.Judging from the water surface line along the way, the water depth of each chamber upstream of 4# rest pool 36 is about 1.0m, and the water level difference among the 30 chambers is about 0.07m; each chamber 30 downstream of 4# rest pool 36 is affected by the downstream water level, the gradient of the water surface line along the way decreases, the water depth of each chamber 30 gradually decreases, and the height difference among the 30 chambers gradually decreases, and the average height difference among the 7 most downstream chambers 30 is only 0.006m.

[0262] Flow velocity and flow pattern in the fishway: 1. Flow velocity of vertical slit 31: The flow velocity of vertical slit 31 in the fishway changes along the way under different working conditions. Fig.26 . Among them, the 124 vertical slits 31 set in the fishway are numbered 1# vertical slit 31 to 124# vertical slit 31 in the direction from the downstream fishway entrance to the upstream fishway exit. Working condition 1: The flow velocity of each vertical slit 31 upstream of the 2# rest pool 36 does not change much, all at about 0.96m / s. The flow velocity of each vertical slit 311-32# downstream of the 2# rest pool 36 gradually increases due to the decrease in water depth and the increase in the height difference between the pool chambers 30. The flow velocities of the 1-15# vertical slits 31 all exceed the design flow velocity requirement of 1.0m / s, among which the flow velocity of the 1# vertical slit 31 reaches 1.66m / s. Working condition 2: The flow velocity of each vertical slit 31 along the fishway does not change much, all at 0.93-0.98m / s, meeting the design flow velocity requirements. Working condition 3: The flow velocity of each vertical slit 31 upstream of the 3# rest pool 36 does not change much, all at about 0.96m / s. The flow velocity of each vertical slit 311-48# downstream of 3# rest pool 36 is gradually reduced due to the increase in water depth and the decrease in the height difference between 30 pool chambers, among which the flow velocity of 1# vertical slit 31 is 0.48m / s. Under this condition, the flow velocity of each vertical slit 31 along the way meets the design requirements. Condition 4: The flow velocity of each vertical slit 31 along the fishway does not change much, all at 0.93-0.98m / s, meeting the design flow velocity requirements. Condition 5: The flow velocity of each vertical slit 31 upstream of 3# rest pool 36 does not change much, all at around 0.96m / s. The flow velocity of each vertical slit 311-48# downstream of 3# rest pool 36 is gradually reduced due to the increase in water depth and the decrease in the height difference between 30 pool chambers, among which the flow velocity of 1# vertical slit 31 is 0.55m / s. Under this condition, the flow velocity of each vertical slit 31 along the way meets the design requirements. Working condition 6: The flow velocity of each vertical seam 31 upstream of 3# rest pool 36 does not change much, all at about 0.96m / s. The flow velocity of each vertical seam 311-48# downstream of 3# rest pool 36 gradually decreases due to the increase in water depth and the decrease in the height difference between the pool chambers 30. Compared with working condition 5, the flow velocity of vertical seams 31 decreases significantly due to the large increase in the inlet water depth, among which the flow velocity of 1# vertical seam 31 is 0.29m / s. Under this working condition, the flow velocity of each vertical seam 31 along the way meets the design requirements.

[0263] Flow rate and flow pattern of chamber 30: Fig. 27As shown in the figure, the flow patterns of water in each fish pond of the fishway under each working condition are basically the same. Generally speaking, there are two different flow patterns in the pond chamber 30, namely the mainstream area connecting the two-level vertical slits 31 and the reflow area forming a closed streamline. After the water flows out of the vertical slit 31, it deviates to the center of the fish pond under the action of the guide plate 35. When it approaches the next vertical slit 31, it is turned back to the vertical slit 31 under the action of the guide plate 35, and the mainstream presents a significant S-shaped streamline. There is a relatively symmetrical reflow area on both sides of the mainstream, with the reflow on the left side in the counterclockwise direction and the reflow on the right side in the clockwise direction. The above water flow pattern is consistent with the test results of the fishway cross-section model.

[0264] Under various working conditions, the changes in the mainstream flow velocity in each fish pond along the way are shown in Fig.28 . In this experiment, the 120 fish ponds set up in the fishway are numbered as 1#~120# chambers 30 from the downstream fishway entrance to the upstream fishway exit. The test results show that in working conditions 2 and 4, the flow velocity in the chambers 30 does not change much, mostly in the range of 0.72-0.78m / s, because the water depth of each chamber 30 along the way is consistent; in working condition 1, the flow velocity gradually increases from the 30# chamber 30 to the 1# chamber 30, because the inlet water depth is lower than the outlet water depth, and the mainstream flow velocity of the 1# chamber 30 is 1.31m / s; in working conditions 3, 5 and 6, the mainstream flow velocity of each downstream chamber 30 shows a trend of gradually decreasing because the inlet water depth is lower than the outlet water depth. Among them, in working condition 3, the mainstream flow velocity of the 46~120# chambers 30 is mostly 0.72-0.78m / s, and the flow velocity gradually decreases from 0.71m / s to 0.4m / s from the 45# chamber 30 to the 1# chamber 30. Working condition 5, the mainstream flow velocity of 30# to 120# pool chambers 30 is mostly 0.72-0.78m / s, and the flow velocity gradually decreases from 0.70m / s to 0.46m / s from 29# pool chamber 30 to 1# pool chamber 30. Working condition 6, the mainstream flow velocity of 52# to 120# pool chambers 30 is mostly 0.72-0.78m / s, and the flow velocity gradually decreases from 0.70m / s to 0.25m / s from 51# pool chamber 30 to 1# pool chamber 30.

[0265] Flow velocity and flow pattern in rest pool 36: Fig.29 As shown, this fishway project has a total of 4 rest pools 36, of which the 4# rest pool 36 is arranged in the straight section, and the 1-3# rest pools 36 are arranged in the turning section. Compared with the pool chamber 30, the flow pattern of the water flow in the rest pool 36 has changed significantly. Among them, since the longitudinal distance between the baffles 32 at both ends of the 4# rest pool 36 is longer, the water is basically not affected by the downstream baffle 32 after flowing out of the upstream vertical seam 31, and directly hits the left side wall, and then moves close to the side wall. After reaching the end of the rest pool 36, it is affected by the downstream baffle 32 and turns to the vertical seam 31; Fig.30 As shown in a, the 3# rest pool 36 is located downstream of the observation room. Since the fish passage at the observation room 34 is located on the left, the main flow of the corresponding rest pool 36 is close to the left wall of the arc, with a width of about 0.7m, and a large-scale recirculation area inside; Fig.30As shown in b, the flow patterns of the 1# and 2# rest pools 36 are consistent, with the mainstream located inside the turning section, with a width of about 0.7m, and a large-scale recirculation area outside; Fig.30 As shown in a, the width of the fish passageway at the observation room 34 is 1.0m, and the water flow is straight. Under each working condition, the mainstream flow velocity in each rest pool 36 and the fish passageway of the observation room 34 is shown in Table 18. It can be seen from the table that under working conditions 1 and 2, there is no significant difference in the maximum flow velocity in each rest pool 36, all of which are 0.54-0.69m / s; under working condition 3, due to the increase of the inlet water depth, the maximum flow velocity in the 1# rest pool 36 is reduced to 0.41m / s, and the maximum flow velocity of the other rest pools 36 is about 0.55m / s; under working conditions 4 and 5, there is no significant difference in the maximum flow velocity in each rest pool 36, all of which are 0.53-0.65m / s; under working condition 6, due to the increase of the inlet water depth and the decrease of the flow rate from the fishway body, the maximum flow velocity in the 1# rest pool 36 is significantly reduced compared with other working conditions, only 0.27m / s, but still greater than the induced flow velocity of fish, and will not form an obstacle for fish to go upstream. The flow velocity of the fish passage in the observation room under each working condition is between 0.36 and 0.44 m / s, which meets the requirements for fish upstream migration.

[0266] Table 18 Flow rate of rest pool 36 and fish passage in observation room 34 m / s

[0267] Test conditions 1 2 3 4 5 6 1# Rest Pool 36 0.69 0.65 0.41 0.65 0.54 0.27 2# Rest Pool 36 0.67 0.66 0.54 0.65 0.64 0.39 3# Rest Pool 36 0.61 0.6 0.55 0.6 0.59 0.49 4# Rest Pool 36 0.56 0.54 0.54 0.55 0.53 0.55 Observation Room 34 0.44 0.43 0.39 0.41 0.42 0.36

[0268] Flow velocity and flow pattern at the fishway inlet and outlet: Fishway inlet: The fishway inlet is the main entrance for migratory fish to enter the fishway and is the most important component of the fishway. The fishway inlet of this project is arranged about 30m downstream of the power station 27, and the fish are lured by the tail water of the power station 27. Fig.30 c and Fig.32 As shown in the figure, the flow patterns at the inlet of the fishway in each working condition are not much different. Affected by the jet of the last vertical slit 31, the inlet presents a staggered distribution of mainstream and return flow. The mainstream passes the inlet turning point close to the right side wall, and the mainstream width is about 1.0m. The inlet mainstream flow velocity gradually decreases with the increase of downstream water level. The inlet mainstream flow velocity of working condition 1 is the largest, which is 0.69m / s. The inlet mainstream flow velocity of working condition 6 is the smallest, which is 0.15m / s, which is lower than the induced flow velocity of migratory fish and does not meet the design requirements. The mainstream flow velocity of the fishway inlet under each working condition is shown in Table 19. Fig.32 As shown in Figure a, under various operating conditions of the fishway, the flow field characteristics of the river channel near the inlet are basically the same, the flow velocity distribution is relatively uniform, the water flow is smooth, and the water flow velocity is between 0.25 and 0.4 m / s, which is between the induced flow velocity and the critical swimming speed of the fish passing object, and can achieve a better fish luring effect.

[0269] Table 19 Mainstream flow velocity at the fishway inlet

[0270] Test conditions 1 2 3 4 5 6 Reservoir water level m 8.7 8.7 8.7 8 8 8 Water level below dam (m) -0.52 0.18 1.84 -0.52 0.18 1.84 Inlet mainstream flow rate m / s 0.69 0.4 0.21 0.38 0.26 0.15

[0271] Fishway exit: Fig.32 As shown in b, the fishway outlet is arranged on the left bank about 150m upstream of the dam. According to the observation of the overall model of the hub, the water flow near the fishway outlet is smooth. Affected by the great water depth of the reservoir area, the flow velocity is mostly between 0.03 and 0.1m / s, which basically meets the design requirements.

[0272] Summary of the design scheme: Under the engineering layout conditions of the design scheme, the water depth of the 30m pool in the upstream section of the fishway is mainly affected by the water level of the reservoir area, and the water depth of each pool is basically consistent with the water depth of the fishway outlet; the water depth of the 30m pool in the downstream section of the fishway is obviously affected by the change of the downstream water level, and the water depth changes greatly; under all working conditions, the water depth of each pool along the way meets the design requirement of not less than 1.0m; the flow rate of the fishway is mainly controlled by the water level of the upstream reservoir area, and is basically not affected by the change of the downstream water level. Under the working condition of the reservoir water level of 8.7m, the flow rate of the fishway is 0.74m 3 / s, when the water level in the reservoir is 8.0m, the flow rate of the fishway is 0.44m 3 / s; Under the operating conditions of 8.0m reservoir water level, the flow velocity of each vertical seam 31 along the way meets the requirements; when the reservoir water level is 8.7m, when the downstream water level is lower than 0.18m, the flow velocity of the vertical seam 311-15# vertical seam 31 below 1# rest pool 36 exceeds the design flow velocity requirement; Under operating conditions 2 and 4, the mainstream flow velocity of each pool chamber 30 along the way does not change much, mostly in the range of 0.72-0.78m / s; Under operating condition 1, the flow velocity gradually increases from 30# pool chamber 30 to 1# pool chamber 30, and the maximum flow velocity of 1# pool chamber 30 is 1.31m / s; Under operating conditions 3, 5 and 6, the mainstream flow velocity of each pool chamber 30 downstream shows a trend of gradually decreasing. Among them, the flow rate of 1# chamber 30 in working condition 6 is the smallest, which is 0.25m / s; the mainstream 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 rates at the fishway inlet in other working conditions are 0.21-0.69m / s. The water flow in the river near the inlet is smooth, with a flow rate of 0.25-0.4m / s, which is between the induced flow rate and the critical swimming speed of the fish object, and can achieve a good fish attracting effect; the water flow at the fishway outlet is smooth, and the flow rate is mostly within 0.1m / s, and the water flow is relatively smooth, meeting the design requirements.

[0273] Experimental study of optimization scheme: Optimization ideas: Through the experimental demonstration of the fishway design scheme, it was found that there are two problems: First, when the water level in the reservoir is 8.7m and the downstream water level is lower than 0.18m, the flow rate of some pool chambers 30 and vertical seams 31 arranged in the most downstream straight section exceeds the design requirements. Second, under the conditions of the reservoir water level of 8.0m and the downstream water level of 1.84m, the flow rate at the fishway inlet is too low, which is less than the induced flow rate of fish. The main reason for the problem that the vertical seams 31 in the fishway trough body and the flow rate in the fish pond exceed the design requirements is that the fishway design parameters cannot fully adapt to the water level changes at the inlet. The fishway trough body is a continuous water-passing structure. Under the premise that the flow rate of each pool chamber 30 is consistent, the water depth of the pool chamber 30 in the lower section of the fishway is reduced, causing its flow rate to increase significantly. Based on the above analysis, the proposed optimization ideas are: first, reduce the flow rate of the fishway trough body to make it compatible with the water depth of the pool chamber 30 in the lower section of the fishway under low water level conditions; second, increase the water depth of the pool chamber 30 with excessive flow rate to reduce the flow rate. As for the fishway import problem, the main consideration is to solve it by importing water.

[0274] Optimization Plan 1: Optimization Engineering Measures: Optimization Plan 1 intends to reduce the flow rate of the fishway by reducing the width of the vertical slits 31 of some chambers 30 at the upstream outlet section of the fishway, thereby reducing the flow rate of the vertical slits 31 of the chambers 30 near the inlet. The specific measures are: reduce the width of the vertical slits 31 of the 30 most upstream chambers 30. To avoid adverse flow conditions caused by sudden changes in the width of the vertical slits 31, adjust the width of the vertical slits 31 of the 10 most upstream chambers 30 to 0.3m, adjust the width of the vertical slits 31 of the subsequent 10 chambers 30 to 0.35m, and adjust the width of the vertical slits 31 of the next 10 chambers 30 to 0.4m. See the layout of the optimization plan for details. Fig.33 . Analysis of test results: The optimization scheme was tested under two typical conditions: condition 1 (high water level upstream and low water level downstream) and condition 4 (low water level upstream and downstream). The test results show that due to the reduction in the width of the vertical slit 31 in the outlet section, the flow rate of the fishway is effectively reduced. Under condition 1, the flow rate of the fishway is reduced from 0.74m3 / s in the design scheme to 0.53m3 / s. Correspondingly, the flow velocities of each chamber 30 and vertical slit 31 near the fishway inlet are reduced, but the flow velocity of the most downstream vertical slit 31 (1# vertical slit 31) still exceeds the design requirements and is 1.21m / s. Comparison of the flow velocities of the vertical slit 31 in the optimization scheme 1 and the design scheme for condition 1 is shown in Fig.34 In addition, the test found that under working condition 4 (design minimum water level), due to the reduction of the flow rate of the fishway, the water depth of most of the pool chambers 30 in the middle and lower parts was less than the design solution, and the minimum water depth was 0.78m, which did not meet the design minimum water depth requirement. Fig.35 .

[0275] Optimization Plan 2: Optimization measures: It is planned to increase the water depth of the pool 30 by lowering the bottom elevation of 15 pools 30 (1-15#) and the inlet of the most downstream straight section, so as to reduce the flow velocity of the vertical seam 31. The specific measures are: lowering the bottom elevation of the fishway inlet from -1.52m to -2.22m, and adjusting the bottom slope of the pool 30 of the most downstream straight section from 1.95% to 3.24%. See the optimization plan layout for details. Fig.36 . Analysis of test results: The optimization scheme was tested under the six working conditions listed in Table 17. The test results show that the water surface line and flow rate along the fishway under each working condition of the optimization scheme 2 are basically consistent with the design scheme. The water depth of each pool chamber 30 in the most downstream straight section increases significantly due to the decrease in the bottom elevation, and the flow velocity of each pool chamber 30 and the vertical seam 31 decreases significantly. Under working condition 1, the flow velocity of the 1# vertical seam 31 decreases from 1.66m / s to 0.98m / s, and the mainstream flow velocity of the 1# pool chamber 30 decreases from 1.31m / s to 0.76m / s. The maximum flow velocity of the vertical seam 31 and the pool chamber 30 occurs at the place where the bottom slope changes, that is, the 16# vertical seam 31 and the 15# pool chamber 30, with flow velocities of 1.08m / s and 0.79m / s, respectively. The minimum flow velocity of the vertical seam 31 and the pool chamber 30 occurs in the 1# vertical seam 31 and the 1# pool chamber 30 of working condition 6, with flow velocities of 0.25m / s and 0.21m / s, which basically meet the design requirements. The water surface line along the fishway, the flow velocity of the vertical seam 31, and the flow velocity of the pool chamber 30 under each working condition are shown in Figure 2. Fig.37 , Fig.38 and Fig.39 .

[0276] The flow pattern of the water flow at the fishway inlet under each working condition of the optimization scheme does not change much from the design scheme. Due to the decrease in the inlet bottom elevation and the increase in water depth, the corresponding inlet flow rate decreases. The comparison of the mainstream flow rate at the fishway inlet under each working condition and the design scheme is shown in Table 20. It can be seen from the table that the flow rate at the fishway inlet in working condition 1 is the largest, which is 0.4m / s. The flow rate at the fishway inlet in working condition 6 is the smallest, which is 0.11m / s. Under working conditions 3 and 6, that is, the highest downstream operating water level conditions, the inlet flow rate is lower than the induced flow rate of migratory fish (0.2m / s), which does not meet the design requirements. In this regard, the model has carried out water replenishment tests for the above two working conditions. The test shows that in order to ensure that the mainstream flow rate at the fishway inlet is not lower than the induced flow rate of migratory fish, the minimum water replenishment flow rates of working conditions 3 and 6 are 0.7m 3 / s, 1.0m 3 / s. The inlet flow pattern before and after water replenishment is shown in Fig.40 .

[0277] Table 20 Main flow velocity at the fishway inlet and water replenishment flow rate under various working conditions

[0278] Operating conditions 1 2 3 4 5 6 Design inlet flow rate m / s 0.69 0.4 0.21 0.38 0.26 0.15 Optimization scheme 2 inlet flow rate m / s 0.42 0.27 0.17 0.25 0.2 0.11 <![CDATA[Makeup water flow rate m 3 / s]]> -- -- 0.7 -- -- 1

[0279] Summary of optimization scheme: In view of the problems existing in the design scheme, two optimization schemes were tested based on the two ideas of reducing the flow rate of the fishway body and increasing the water depth of the chamber 30 where the flow rate exceeds the standard. Optimization scheme 1 takes the measure of reducing the width of the vertical slit 31 of the outlet section to achieve the purpose of reducing the flow rate of the fishway, so that the flow rate of each chamber 30 and the vertical slit 31 of the most downstream straight section is reduced, but it still does not meet the design flow rate requirement. In addition, the reduction in the flow rate of the fishway caused a significant drop in the water level of most of the middle chambers 30. Under working condition 4, the water depth of the chamber 30 does not meet the minimum design water depth requirement of the fishway. Optimization scheme 2 increases the water depth of the chamber 30 and effectively reduces the flow rate of the vertical slit 31 by reducing the 15 chambers 30 [1-15#] and the inlet bottom elevation of the most downstream straight section. The flow rates of the fishway vertical seam 31 and the pool chamber 30 can meet the design requirements under all working conditions. However, the lower the bottom elevation of the fishway inlet and the deeper the water depth, the significantly reduced the inlet flow rate. In working conditions 3 and 6, i.e., the highest downstream operating water level, the inlet flow rate is 0.2 m / s lower than the induced flow rate of migratory fish, which does not meet the design requirements. In order to ensure that the mainstream flow rate at the fishway inlet is not lower than the induced flow rate of migratory fish, water needs to be replenished at the fishway inlet. The minimum replenishment flow rates for working conditions 3 and 6 are 0.7 m / s, respectively. 3 / s, 1.0m 3 / s.

[0280] In summary, by establishing an overall fishway model with a geometric scale of 1:25 and combining the results of local model tests, the layout scheme of the vertical slot fishway 23 in hub 1 was demonstrated and optimized experimentally, and the following conclusions were obtained:

[0281] According to the design plan, the flow rate of the fishway is mainly controlled by the water level of the upstream reservoir and is basically not affected by the changes in the downstream water level. When the water level in the reservoir is 8.7m, the flow rate of the fishway is 0.74m3 / s; when the water level in the reservoir is 8.0m, the flow rate of the fishway is 0.44m3 / s; under each working condition, the water depth of each pool 30 along the way meets the design requirement of not less than 1.0m; when the water level in the reservoir is 8.7m, when the downstream water level is lower than 0.18m, the flow velocity of the vertical seam 31 and the pool chamber 30 near the fishway inlet below the 1# rest pool 36 exceeds the design requirement, the maximum flow velocity of the vertical seam 31 is 1.66m / s, and the maximum flow velocity of the pool chamber 30 is 1.31m / s; the flow velocity at the fishway inlet gradually decreases with the increase of the downstream water level, the mainstream flow velocity at the inlet of working condition 6 is only 0.15m / s, which does not meet the design requirements, and the flow velocity at the fishway inlet in other working conditions is 0.21-0.69m / s; the water flow at the fishway outlet is smooth, the flow velocity is mostly within 0.1m / s, the water flow is relatively smooth, and it meets the design requirements.

[0282] In response to the problem of excessive flow rate in the lower section of the vertical seam 31 and the pool in the fishway design, optimization measures were proposed 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 chamber 30 [from 1.95% to 3.24%]. By increasing the water depth of the pool chamber 30, the purpose of reducing the flow rate was achieved to meet the requirements. Under the operating conditions of working conditions 3 and 6 [high water level downstream], the flow rate at the fishway inlet was lower than the induced flow rate of migratory fish [0.2m / s], which did not meet the design requirements and required water replenishment at the fishway inlet. The minimum water replenishment flow rates of working conditions 3 and 6 were 0.7m3 / s and 1.0m3 / s, respectively.

[0283] Conclusion and suggestions: The model test research project of the fishway project at the hub uses a variety of technical means such as data analysis, on-site testing, and physical model testing to carry out four parts of research content: 1. Research on the swimming ability of target fish species passing through the fishway to clarify the migratory ecological characteristics of the fish passing through; 2. Design of fishway 2 scheme, and propose a preliminary design scheme for the fishway plane and the structure layout of chamber 30; 3. Physical model test of the local section of the fishway project, based on the preliminary design scheme, carry out the demonstration and optimization research on the structural layout of chamber 30 of vertical slit fishway 23, and propose a recommended scheme for the structure of chamber 30; 4. Overall model test research of the fishway, based on the preliminary design scheme and the recommended scheme for the structure of chamber 30, carry out the overall hydraulic characteristics test research of the vertical slit fishway 23, and propose a recommended scheme for the overall layout of the fishway and operation suggestions. The specific conclusions are as follows:

[0284] Study on the swimming ability of target fish: Through the analysis and verification of existing data, it is concluded that the main purpose of the fishway 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. The main fish passing targets of Hub 1 fishway should be downstream migratory fish [CA] and upstream migratory fish [AN]. After verification, the main fish passing targets are: downstream migratory fish [CA] flower eel, eel, and flower perch, upstream migratory fish [AN] seven-thread anchovy and flower scorpion; the objects to be taken into consideration are: spotted scorpion, Chinese black tang, spotted tongue goby, Ju's silverfish, tongue goby, semi-ridged Chinese [fish mang] and other estuarine fish, and Hepu mitten crab. The fish passing season is from November to September of the following year. The main fish passage specifications of vertical slot fishway 23 are 40-600mm, and the eel passage 24 are 100-500mm. The design indicators of the fishway at the hub are determined by testing the swimming ability of the main fish passage objects such as sea bass, eel, red-eyed trout, and dace, as well as the fish currently distributed in this section of the river. The flow rate range of the fish hole / slit of vertical slot fishway 23 is 0.54-1.37m / s, and the average flow rate can be about 1.0m / s; the average flow rate of the pool chamber 30 is 0.24-0.67m / s; the inlet fish attracting flow rate should not be lower than the fish sensing flow rate of 0.2m / s, and should be 0.35-0.73m / s; the outlet flow rate should not be still water, and should be 0.24-0.35m / s. Eels are fish with climbing habits. Although their measured swimming ability is relatively small, the eel track 24 should not be designed simply based on the measured swimming ability. The eel track 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 their climbing.

[0285] Design of fishway 2: Based on the migratory behavior characteristics of the target fish in hub 1 and the water dispatching plan for the fishway at hub 1, the fishway adopts a double fishway design of vertical slot fishway 23 and eel way 24. Both vertical slot fishway 23 and eel way 24 are arranged on the left bank, close to the shore side of the tailwater of power station 27. Eel way 24 meets vertical slot fishway 23 near the downstream observation room 34, and then merges into vertical slot fishway 23. The design plan of vertical slot fishway 23 is that the bottom slope is 1:51.02, the total length is 458m, and one inlet is set with a bottom elevation of -1.52m and one outlet with a bottom elevation of 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. The design plan of the eel channel 24 is as follows: at the intersection of the vertical retaining wall on the left bank and the downstream bank, a vertical eel channel 24 entrance is set towards the bank, starting from the riverbed bottom plate at -7.5m, an entrance is set every 1m, and a total of 7 eel entrances 33 are set; 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 upstream. An observation room 34 is provided on the upstream side of the intersection of the vertical slot fishway 23 and the eel way 24 for counting the species and quantity of fish that have successfully gone upstream and evaluating 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 functions of publicity and demonstration.

[0286] Physical model test of local section of fishway project: Based on the preliminary design of vertical slit fishway 23, a local section model of fishway with a geometric scale of 1:4 was established. Through the test, it was found that the scale of the pool chamber 30, the width of the vertical slit 31, and the main bottom slope design of the design scheme were basically reasonable and met the upstream requirements of the target fish; the flow rate of the fishway was about 0.50m3 / s, and the velocity coefficient of the partition 32 was φ=0.97; the diversion angle was small, which made the average flow velocity of the vertical slit 31 (1.11m / s) exceed the design requirements, and there was no obvious deflection of the mainstream in the pool chamber 30, and other unfavorable water flow conditions in the pool chamber 30. In view of the problem that the diversion angle is too small, resulting in the water flow conditions in the vertical seam 31 and the pool chamber 30 not meeting the requirements of fish upstreaming, the diversion angle is adjusted to optimize the water flow structure of the pool chamber 30, with the idea of ​​promoting the mainstream deflection in the pool chamber 30 and increasing the mainstream energy dissipation. By comparing the water flow conditions of the pool chamber 30 and the vertical seam 31 of the three groups of optimization schemes, it is proposed to keep 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 increase the diversion angle to 45°. The scheme has an average water level difference of 0.07m in the pool chamber 30, an average flow velocity of 1.01m / s in the vertical seam 31, and a flow velocity distribution of 0.99-1.06m / s in the vertical seam 31. The flow velocity of the fish-passing vertical seam 31 meets the requirements of an average flow velocity of 1m / s and a flow velocity distribution range of 0.54-1.37m / s. The flow velocity coefficient φ=0.86, corresponding to a design water depth of 1m, and the flow rate of the vertical seam 31 is about 0.45m3 / s, which is about 7% less than that of the design scheme.

[0287] Fishway overall model test: Based on the recommended scheme of the pool chamber 30 structure and the preliminary design scheme of the vertical slit fishway 23, a fishway overall model with a geometric scale of 1:15 was established. The study showed that the flow rate of the fishway is mainly controlled by the water level of the upstream reservoir area and is basically not affected by the change of the downstream water level. 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 reservoir water level is 8.7m, when the downstream water level is lower than 0.18m, the flow rate of the vertical slit 31 and pool chamber 30 in the lower section of the fishway [below 1# rest pool 36] exceeds the design requirements, and the vertical slit 31 The maximum flow rate is 1.66m / s, and the maximum flow rate of chamber 30 is 1.31m / s; the flow rate at the fishway inlet gradually decreases with the increase of downstream water level. The mainstream flow rate at the inlet of condition 6 is only 0.15m / s, which does not meet the design requirements. The flow rates at the fishway inlet of other conditions are between 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. The water flow is relatively smooth, meeting the design requirements. In view of the problem of excessive flow rate in the vertical seam 31 and the pool in the lower section of the fishway in the design scheme, optimization measures were proposed to reduce the bottom elevation of the fishway inlet [from -1.52m to -2.22m] and increase the slope of the pool chamber 30 in the most downstream straight section [from 1.95% to 3.24%], so as to achieve the purpose of reducing the flow rate of the vertical seam 31 and the pool chamber 30 to meet the requirements; under the operating conditions of working conditions 3 and working conditions 6 [the water level below the dam is higher than 0.18m], the flow rate at the fishway inlet is lower than the induced flow rate of migratory fish [0.2m / s], which does not meet the design requirements and is difficult to ensure the fish attracting effect of the fishway inlet. Water replenishment is required at the fishway inlet. Model tests have shown that in order to ensure that the fishway inlet reaches the induced flow rate of migratory fish, the minimum water replenishment flow rates of working conditions 3 and working conditions 6 are 0.7m3 / s and 1.0m3 / s respectively. After communicating with the design unit, it was found that this project is restricted by water resources and the implementation of imported water replenishment measures is difficult. Based on this, it is recommended to install water flow thrusters at the fishway inlet to meet the inlet fish attracting flow rate requirements.

[0288] In summary, the optimized overall layout structure and operation plan of the fishway are as follows: the structure of the canal fishway includes an eel way 24 and a vertical slot fishway 23. 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. A climbing matrix 20 is provided in the eel way 2, one end of the eel way 2 is connected to the middle part of the vertical slot fishway 23, and the other end extends to the bottom of the canal. The part of the vertical slot fishway 23 located upstream of the eel way 2 is also provided with a climbing matrix 20. The eel way 2 and the part of the vertical slot fishway 23 located upstream of the eel way 2 together form a migratory channel.

[0289] A preferred solution is that the climbing matrix 20 includes a plurality of rows of pile structures 22 , wherein each row is provided with at least two pile structures 22 at intervals, and adjacent rows of pile structures 22 are staggered along the length direction of the eel way 24 or the vertical slot fishway 23 .

[0290] The structure of a canal fishway of the present application provides climbing assistance for eels by staggering the pile structures 22 and adjacent rows of pile structures 22 along the length direction of the eel way 24 or the vertical slot fishway 23. At the same time, compared with the bristle base, the pile structure 22 does not have bristles, so there is no debris blockage and it is easy to clean. In addition, the pile structure 22 can play a role in friction resistance, water flow concussion and diffusion to dissipate energy along the way, thereby improving the flow state and reducing the flow rate of the vertical slot 31 passing through the fish. The pile structure 22 can be a cylindrical tube or a pier, and the staggered pipes or piers designed at the bottom provide a fulcrum for the eels to climb. The pipes are preferably cylindrical tubes or frustum tubes. Fig.30 As shown, further preferably, a through hole 21 is provided on the upstream side of the frustum tube; the upper edge of the frustum tube and the edge of the through hole 21 are in arc transition; the height of the frustum tube is greater than the bottom diameter of the tubular structure, and the top diameter of the frustum tube is smaller than the bottom diameter of the frustum tube. A preferred solution: the bottom diameter of the pile structure 22 is greater than the top diameter of the pile structure 22.

[0291] A preferred solution is that 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, 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.

[0292] A preferred solution: the pile structure 22 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 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 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 21 is provided on the upstream side of the tubular structure, which can provide better migratory conditions for small Hepu mitten crabs and eels, and at the same time, the tubular structure cooperates with the through hole 21 to better play the role of friction resistance along the way, water flow counteraction and diffusion to dissipate energy, and thus better improve the flow state and reduce the flow velocity of the vertical slit 31 through which fish pass. Preferably, the migratory channel includes a driving mechanism, a four-bar linkage, a base and a fishway bottom plate structure. The base and the fishway bottom plate structure are both inclined, and the pile structure 22 is arranged on the fishway bottom plate structure. The driving mechanism drives the four-bar linkage to drive the fishway bottom plate structure to reciprocate and slide with the base.

[0293] The eel way 24 and the vertical slot fishway 23 are both arranged on the tailwater side of the power station 27 of the hub 1, which is the mainstream edge of the physical barrier [sluice] under most working conditions, and better meets the conditions for attracting and bringing in fish.

[0294] This embodiment also discloses a method for constructing a fishway, which is used to form the structure of the canal fishway of this application, and includes the following steps: S1: constructing a vertical slit fishway 23; S2: constructing an eel way 24, and connecting the eel way 24 with the vertical slit fishway 23; S3: adjusting the slope and diversion angle of the eel way 24. A method for constructing a fishway of this application uses the design method of the canal fishway of this embodiment as a theoretical basis, first constructing the vertical slit fishway 23, then constructing the eel way 24, and finally adjusting the slope and diversion angle of the eel way 24, so as to construct a more optimized structure of the canal fishway, and the whole process is simple to construct and has low construction cost.

[0295] 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 method for designing a canal fishway, characterized in that: The following steps are involved: S1: Establish a fishway database at the hub, evaluate the swimming ability of target fish species passing through the fishway, and determine the migratory ecological characteristics of the target fish species; S2: Design the fishway scheme based on the ecological characteristics of the fish migration and the fishway database at the hub, and determine the preliminary design scheme of the fishway structure. The fishway (2) in the preliminary design of the fishway structure includes an eelway (24) and a vertical slot fishway (23), wherein the migratory fish in the eelway (24) include eels and mitten crabs, and the migratory fish in the vertical slot fishway (23) include red-eyed trout and dace, and one end of the eelway (2) is connected to the middle of the vertical slot fishway (23), and the other end extends to the bottom of the canal; S3: Based on the preliminary design scheme of the fishway structure, a local cross-section physical model of the fishway project is designed, and a local cross-section physical model test of the fishway project is conducted to obtain a recommended scheme for the pool chamber structure located upstream of the eel way (24) in the vertical slot fishway (23); S4: Establish an overall model of the fishway based on the preliminary design scheme and the recommended pool structure scheme, and conduct an overall model test of the fishway to determine the overall structural scheme of the fishway.

2. A method for designing a canal fishway according to claim 1, characterized in that: Step S1 includes the following steps: evaluating the swimming ability of the target fish species passing through the fishway and determining the migratory ecological characteristics of the target fish species passing through the fishway: S11. Confirm the hub structure and the purpose of fish passing through the hub; S12. Classify estuarine fish communities based on the interaction between freshwater runoff and seawater intrusion, and obtain the classification results of fish species passing through the estuary; S13. confirm the ecological habits of each fish species passing through based on the classification results of the fish species passing through, determine the fish species passing through specifications and seasons based on the ecological habits of each fish species, formulate initial technical parameters of the fishway, and obtain fish species that meet the requirements, wherein the initial technical parameters of the fishway include the number of fishways, the design flow rate of the fishway, the layout of the fishway, the structure of the fishway, the inlet of the fishway, the outlet of the fishway, the water consumption of the fishway, and the operating water level of the fishway; S14. confirming the time period of fish passage at the fishway at the hub (1) based on the fish passage season; S15. During the fish passing time period confirmed in step S14, the swimming ability of the fish obtained in step S13 is tested at the hub (1), and the swimming ability test results of different fish are obtained to clarify the migratory ecological characteristics of the fish passing objects at the hub (1).

3. A method for designing a canal fishway according to claim 2, characterized in that: Test the fish's current-seeking characteristics and ability to overcome currents. The test indicators include the induced flow velocity, critical swimming speed and surging swimming speed; among which: The induction flow rate test is as follows: Place more than 10 fish in a test annular test tank, and gradually increase the flow rate until half of the test fish turn around to the countercurrent direction. At this time, the flow rate is the induced flow rate of the test fish group; Place the test fish individually in the still water of the test annular test tank, and then gradually increase the flow rate until the test fish turns to the countercurrent direction. At this time, the flow rate is the induced flow rate of the individual test fish; The critical swimming speed test is as follows: The body length and weight of the tested fish are measured and the fish are placed in the swimming area (12) of the annular test water tank, and the initial flow velocity, flow velocity gradient and time gradient of the annular test water tank are set; The dissolved oxygen and temperature were tested at regular intervals. When the fish reached the end grid of the swimming area and could not swim, the fish were removed from the swimming area (12) and the weight of the fish was tested. The critical swimming speed was calculated by assuming that the swimming speed of the fish was equal to the water flow speed and ignoring the retention effect. The swimming ability of the knife-toothed anchovy is tested by analogy with that of the seven-thread anchovy.

4. A method for designing a canal fishway according to claim 2, characterized in that: The step S2 specifically comprises the following steps: S21. 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 object and the initial technical parameters of the fishway, wherein the design flow rate of the vertical slot fishway (23) includes the flow rate through the fish hole / slit, the inlet fish attracting flow rate, the outlet flow rate and the main structure flow rate of the vertical slot fishway (23); S22. Based on the fishway database at the hub, the initial technical parameters of the fishway, the design flow rate of the eelway (24), the design flow rate of the vertical slot fishway (23), and the tailwater position of the power station (27) in the hub (1), determine the layout positions of the vertical slot fishway (23) and the eelway (24), as well as the position where the eelway (24) connects to the vertical slot fishway (23); S23: 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); S24: 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); S25: Determine the width of the vertical slot fishway (23) based on the width parameter of the vertical slot fishway inlet (26); S26: 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); S27: 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.

5. A method for designing a canal fishway according to claim 4, 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.

6. A method for designing a canal fishway according to claim 1, characterized in that: Step S3 specifically includes the following steps: S31. Designing a local section physical model of the fishway project based on the preliminary design scheme, wherein the local section physical model of the fishway project is designed as a normal model, and the local section physical model of the fishway project is designed according to the gravity similarity criterion, and the overall model design scheme of the fishway is checked for geometric similarity, water flow motion similarity and dynamic similarity; S32. Conduct a fishway cross-section model test, measure and evaluate fishway parameters, and find out the parameters that exceed the standard and the reasons for the parameters exceeding the standard, wherein the fishway parameters include the water level difference between the upstream and downstream of adjacent chambers (30), the flow velocity distribution of the vertical slits (31), the flow field distribution in the chambers (30), the flow state in the chambers (30) and the local water flow in the chambers (30), and the average water depth of each chamber (30), the average water level difference of each chamber (30), the flow velocity distribution of the vertical slits (31) of each chamber (30), and the flow field distribution in the chambers (30); S33. After improving the cause in S32, repeat S31-S33 until all fishway parameters meet the design requirements, and form a recommended solution for the pool chamber (30) structure based on the fishway parameters.

7. A method for designing a canal fishway according to claim 6, characterized in that: In step S31, based on the preliminary design scheme of the vertical slot fishway (23), the design bottom slope I of the pool chamber (30), the average low tide level at the estuary, the operating water level at the outlet of the vertical slot fishway (23), and the minimum water depth in the pool chamber (30) are determined; the corresponding upstream design low water level condition of the fishway, the corresponding downstream design low water level condition of the fishway, and the most unfavorable design condition are determined, and based on the design bottom slope I of the pool chamber (30), the average low tide level at the estuary, the operating water level at the outlet of the vertical slot fishway (23), the minimum water depth in the pool chamber (30), the corresponding upstream design low water level condition of the fishway, the corresponding downstream design low water level condition of the fishway, and the most unfavorable design condition, a local cross-section physical model of the fishway project is designed, wherein the most unfavorable design condition is a condition in which the volume of the energy dissipation water body is the minimum value on the basis of the unchanged geometric scale of the pool chamber (30).

8. A method for designing a canal fishway according to claim 6, characterized in that: In step S32, the flow velocity distribution of the vertical slit (31) is evaluated as follows: Measuring the flow velocity of at least part of the vertical slits (31), arranging a plurality of measuring points at intervals along the water depth vertically on the center line of each vertical slit (31), and obtaining the flow velocity distribution and average flow velocity of the vertical slit (31) based on the measuring points; Based on the swimming ability test results of the target fish species, a recommended range of flow velocity distribution and a recommended average flow velocity value of the vertical slit (31) are obtained; evaluating whether the flow velocity distribution of the vertical slit (31) exceeds the recommended flow velocity distribution range of the vertical slit (31), and whether the average flow velocity of the vertical slit (31) is greater than the recommended value of the average flow velocity of the vertical slit (31); The velocity coefficient of the baffle (32) is obtained based on the average vertical velocity of the fish-passing vertical slit (31), the average water level difference of the baffle (32), the average flow rate of the fishway and the water volume of the pool chamber (30). and the power dissipation E per unit water volume of the pool chamber (30), and the velocity coefficient of the baffle (32) And the unit water power dissipation E of the pool chamber (30) meets the design requirements.

9. A method for designing a canal fishway according to claim 6, characterized in that: In step S32, the flow field distribution in the pool chamber (30) is evaluated as follows: A pool chamber (30) is selected to measure the surface flow field distribution thereof, N measuring lines are arranged along the width of the pool chamber (30), and L measuring points are arranged along the length of each measuring line of the pool chamber (30); Based on the test results of the measuring points, the mainstream entry form, mainstream path, circulation position and recirculation zone integrity of the pool chamber (30) are evaluated, wherein the recirculation zone influence range K3 and the maximum flow velocity v of the recirculation zone are used. cmax To quantify the impact of the recirculation zone on fish.

10. A method for designing a canal fishway according to claim 9, characterized in that: The influence range K3 of the recirculation zone and the maximum flow velocity v of the recirculation zone cmax To quantify the impact of the recirculation zone on fish, specifically: K3=L c B c / (LB), where L c is the maximum length of the recirculation zone, B c is the maximum width of the recirculation zone.

11. A method for designing a canal fishway according to claim 10, characterized in that: The influence range of the reflow zone K3 is 0.12~0.17; the reflow intensity range is 0.18~0.24m / s.

12. A method for designing a canal fishway according to claim 10, characterized in that: When the influence range of the recirculation zone is too large, based on the diversion angle at the vertical slit (31) in the preliminary design scheme, at least a second diversion angle and a third diversion angle are set, and the second diversion angle and the third diversion angle are respectively substituted into the local cross-section physical model of the fishway project to form a new local cross-section physical model of the fishway project, and a new fishway cross-section model test is carried out to obtain the average flow velocity of the vertical slit (31), the maximum flow velocity of the vertical slit (31), and the minimum flow velocity of the vertical slit (31) at each diversion angle, and obtain an optimized structural scheme, wherein the second diversion angle and the third diversion angle are both greater than the diversion angle at the vertical slit (31) in the preliminary design scheme.

13. A method for designing a canal fishway according to claim 6, characterized in that: Based on the optimized structural scheme, the water level difference of the pool chamber (30), the flow velocity distribution of the vertical seam (31) and the flow field distribution in the pool chamber (30) are calculated, and it is confirmed whether the water level difference of the pool chamber (30), the flow velocity distribution of the vertical seam (31) and the flow field distribution in the pool chamber (30) meet the design requirements. If so, the optimized structural scheme is the recommended structural scheme for the pool chamber (30).

14. A method for designing a canal fishway according to claim 6, characterized in that: Step S4 specifically includes the following steps: S41: establishing a design scheme for an overall model of the fishway based on the preliminary design scheme and the recommended scheme for the structure of the pool chamber (30); S42: based on the overall model design scheme of the fishway, the overall model of the fishway is produced. The overall model of the fishway is designed as a normal model. The overall model of the fishway is designed according to the gravity similarity criterion. The overall model of the fishway is checked for geometric similarity, water flow motion similarity and dynamic similarity. S43: Conducting fishway overall model test based on the fishway overall model, optimizing the overall layout structure scheme and operation scheme of the fishway, and thus obtaining the final fishway overall structure scheme.

15. A method for designing a canal fishway according to claim 14, characterized in that: Step S41 specifically includes the following steps: Establish the basic structure scheme of the overall model design of the fishway based on the preliminary design scheme; Based on the optimized local cross-section structural scheme of the fishway project, a pool chamber (30) structural scale scheme is established, and the pool chamber (30) structural scale scheme is added to the basic structural scheme of the overall model design of the fishway to obtain the overall model design scheme of the fishway; The experimental conditions are selected according to the designed operating water level of the fishway upstream and the designed operating water level of the fishway downstream, wherein the experimental conditions include the upstream highest operating water level condition, the upstream lowest operating water level condition, the downstream lowest operating water level condition, the condition where the inlet water depth is consistent with the outlet water depth when the upstream highest water level is the same, and the highest operating water level condition; Based on the production of the fishway overall model and various experimental working conditions, the fishway overall model test is carried out to obtain the water depth in each pool chamber (30) and the average height difference between the pool chambers (30) in each working condition.

16. A method for designing a canal fishway according to claim 15, characterized in that: Based on the overall model test of the fishway, the flow velocity of the vertical slit (31), the flow velocity and flow pattern of the pool chamber (30), the flow velocity and flow pattern in the rest pool (36), and the flow velocity and flow pattern at the inlet and outlet of the vertical slit fishway (23) under various working conditions are obtained.

17. A method for designing a canal fishway according to claim 15, characterized in that: When the vertical slits (31) in the fishway body and the flow rate in the fish pond exceed the design requirements, the flow rate of the vertical slit fishway (23) body is reduced to adapt to the water depth of the lower section pool chamber (30) of the fishway under low water level conditions.

18. A method for designing a canal fishway according to claim 15, characterized in that: When the vertical seams (31) in the fishway body and the flow velocity in the fish pond exceed the design requirements, the water depth of the flow velocity exceeding pool chamber (30) is increased and the flow velocity is reduced.

19. A structure of a canal fishway, characterized in that: The canal fishway is designed by the design method of any one of claims 1 to 18, the structure of the canal fishway includes an eel way (24) and a vertical slot fishway (23), the migratory fish in the eel way (24) include eels and mitten crabs, 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, the eel way (2) is provided with a climbing matrix (20), and the vertical slot fishway (23) is located at the eel. Water retaining structures are arranged at intervals upstream of the channel (2), 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 climbing matrix (20) is also arranged in the pool chamber (30), and the climbing matrix (20) includes a plurality of rows of pile structures (22), wherein at least two pile structures (22) are arranged at intervals in each row, and adjacent rows of the pile structures (22) are staggered with each other along the length direction of the eel channel (24) or the vertical slit fish channel (23).

20. A method for constructing a fishway, characterized in that: The method for forming the structure of the canal fishway as claimed in claim 19 comprises the following steps: S1: Construction of vertical slot fishway (23); S2: constructing an eel way (24) and connecting the eel way (24) with the vertical slit fish way (23); S3: adjusting the slope and diversion angle of the eel channel (24).

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