Floating fishway outlet structure and method adaptive to reservoir area water level amplitude variation

Abstract

The invention discloses a floating fishway outlet structure and method adaptive to reservoir area water level amplitude, the fishway outlet structure comprises a fishway outlet, an adjusting unit is arranged in the fishway outlet, a floating plate is hinged to the adjusting unit, the floating plate is arranged on the outer side of the outlet end of the fishway outlet, the adjusting unit is slidably connected with the fishway outlet, and the adjusting unit is connected with the fishway outlet. A telescopic rod is arranged at the bottom of the adjusting unit, and the bottom of the telescopic rod is connected with the fishway outlet. The first-stage variable-gradient area is arranged at the outlet section of the fishway, the gradient is gradually reduced in the downstream direction, the downstream is connected with the water level flat slope pool, the whole fishway gradient is smoothly transited to the downstream fixed design gradient from the variable-gradient area, and therefore on the premise that the fish passing hydraulic condition is met, the fish passing efficiency is improved. And the application range of a single fishway outlet to the reservoir area water level amplitude variation is expanded.

Description

Technical Field

[0001] This invention belongs to the field of environmental engineering construction design technology, and in particular relates to a floating fishway outlet structure and method adapted to the fluctuation of water level in reservoir areas. Background Technology

[0002] Most of the fishways already built in foreign hydropower projects are low-head fish passages with a head of no more than 10 meters. Due to the characteristics of foreign hydropower projects, there is relatively little research on the design of fishway outlets under conditions of large reservoir level fluctuations. Foreign researchers tend to focus more on the inlet layout and site selection of other fish passage facilities and environmental protection projects besides fishways. Based on the comparison of actual engineering conditions abroad, in contrast, with the increasingly mature dam construction technology in my country, according to incomplete statistics, there are nearly 100 completed and planned high dams in my country. These high dams are mostly concentrated in V-shaped canyons and river valleys in the southwest region. However, they face challenges such as high head and maximum daily water level fluctuations of more than ten meters in the reservoir area. These challenges have become the main bottleneck for the current and future construction and efficient operation of fishways.

[0003] According to the relevant design regulations for environmentally friendly fishway engineering in my country's water conservancy and hydropower projects (hereinafter referred to as fishway engineering), during the main fish passage season, when the water level fluctuation in the upstream reservoir area is large, multiple fishway outlets at different elevations need to be set up in the reservoir area to connect with the water level fluctuations. Typically, one outlet is set up every 1-2 meters according to the water level fluctuation in the reservoir area. To adapt to changes in water level downstream of the dam and in the reservoir area, existing fishway engineering projects mostly adopt a multi-inlet, multi-outlet switching operation mode. However, in actual operation, frequent switching of multiple outlets not only increases the complexity of operation and management, but also, under certain operating conditions, can easily lead to situations where the inflow rate at the fishway outlet has not yet stabilized before being forced to switch to a lower elevation outlet. This results in frequent changes in the hydraulic conditions and complex flow patterns at the fishway outlet in the reservoir area, which is not conducive to fish stably identifying the passage path, thus affecting the overall fish passage efficiency.

[0004] Patent document CN105780716A discloses a fishway experimental device and its operating method. The fishway structure of this device is variable, and the flow rate and slope are adjustable, enabling the study of the hydraulic characteristics and fish passage effect within the fishway under different operating conditions. However, this device is suitable for situations with small water level fluctuations.

[0005] Patent document CN213061927U discloses a fishway outlet gate arrangement structure adapted to large water level fluctuations. This structure superimposes fishway outlets on the same vertical plane and uses cables to open and close fishway outlet gates at different heights, similar to the stratified water intake principle of the Mardang Hydropower Station. However, the technology in this patent still involves setting one gate at each fishway outlet at each elevation, forming a vertical gate group control technology, which also suffers from cumbersome operation and difficult maintenance. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the present invention provides a floating fishway outlet structure and method that adapts to the fluctuation of water level in the reservoir area.

[0007] The present invention is achieved through the following technical solutions.

[0008] The present invention provides a floating fishway outlet structure adapted to the water level fluctuation of a reservoir, including a fishway outlet, which is connected to one end of the fishway located in the reservoir, and a fishway inlet at the other end of the fishway. An adjustment unit is provided inside the fishway outlet, and a floating plate is hinged to the adjustment unit. The floating plate is located outside the outlet end of the fishway outlet. The adjustment unit is slidably connected to the fishway outlet, and a telescopic rod is provided at the bottom of the adjustment unit. The bottom of the telescopic rod is connected to the fishway outlet.

[0009] Preferably, the fishway outlet includes a fishway sidewall and a fishway bottom plate. The fishway bottom plate is vertically arranged on both sides of the fishway sidewall. The float plate is hinged to the fishway sidewall and the adjustment unit on both sides through the float plate rotation shaft. The telescopic rod is connected to the fishway bottom plate.

[0010] Preferably, a support rod is provided on the outer wall of the fishway sidewall, a buffer pad is provided on the support rod, a guide channel is provided on the inner wall of the fishway bottom plate, and a limiting block is provided in the guide channel.

[0011] Preferably, a baffle is provided at one end of the fishway bottom plate near the floating plate, and a water inlet hole is provided on the baffle.

[0012] Preferably, a water level elevation sensor is provided on the floating board.

[0013] Preferably, the telescopic rod includes a bottom rod, an upper rod, and a middle section, the bottom rod is connected to the upper rod through the middle section, and a water level sensor is provided on the surface of the bottom rod.

[0014] Preferably, the middle section includes a hydraulic spring telescopic rod or a hydraulic telescopic rod, wherein the spring telescopic rod includes a hydraulic rod, a height limiting spring and a motor control system, the height limiting spring is disposed on the hydraulic rod, and the hydraulic telescopic rod includes a hydraulic rod and a motor control system.

[0015] Preferably, the adjustment unit includes a slope plate assembly, a first fixing plate, and a second fixing plate. One end of the first fixing plate is hinged to the slope plate assembly, and the other end of the first fixing plate is hinged to the second fixing plate. The slope plate assembly, the first fixing plate, and the second fixing plate are respectively provided with flow-blocking devices.

[0016] Preferably, the variable slope plate assembly includes a first variable slope plate, a second variable slope plate, a third variable slope plate, and a fourth variable slope plate that are hinged in sequence. A plate shaft is provided between the first variable slope plate, the second variable slope plate, the third variable slope plate, and the fourth variable slope plate to achieve hinge connection. The bottom of the plate shaft 52 is connected to a telescopic rod 4, and the plate shaft is slidably connected to the bottom plate of the fishway through a guide channel.

[0017] A method for adjusting the outlet structure of a floating fishway to adapt to changes in reservoir water level includes the following steps: S1: By constructing an upward distance-success rate mathematical model, the length and slope of the first, second, third, and fourth slope plates are set according to the upward distance-success rate mathematical model; S2: As the water level in the reservoir rises, the buoyancy of the water causes the floating plate and the first slope plate to rise. The first slope plate causes the second, third and fourth slope plates to rise. Water enters the fishway outlet from the inlet hole. When the water submerges the water level sensor installed on the bottom rod, the water level elevation sensing signal and the water level sensor transmit the sensed signal to the motor control system of the telescopic rod, causing the middle section to start working. This allows the telescopic rod to control the angle of the first, second, third and fourth slope plates to the required range through extension and retraction. S3: When the water level in the reservoir drops, the floating board and the first slope plate drop with the water level. The first slope plate drives the second, third and fourth slope plates to drop. The water level elevation sensor and the water level sensor on the bottom pole detect the water level and transmit the signal to the motor control system of the telescopic pole, so that the middle section starts to work, and the telescopic pole controls the angle of the first, second, third and fourth slope plates to the required range by telescopic control.

[0018] Preferably, the calculation formula for the upstream distance-success rate mathematical model is as follows: In the formula, Success rate; Upward distance under various operating conditions; , These are factor coefficients; This is the distance coefficient; This represents the distance count.

[0019] The beneficial effects of this invention are as follows: This invention establishes a variable slope zone at the fishway outlet, gradually reducing the slope downstream, and connects to a leveling pool downstream. This allows the fishway slope to smoothly transition from the variable slope zone to a fixed design slope downstream. This expands the adaptability of a single fishway outlet to reservoir water level fluctuations while still meeting the hydraulic requirements for fish passage. Through these technical means, this invention can reduce the number of fishway outlets to some extent, reducing the management complexity caused by switching between multiple outlets. Furthermore, the floating structure further enhances the fishway's adaptability to reservoir water level fluctuations, improving overall fish passage stability and operational efficiency.

[0020] This invention analyzes different flow velocities corresponding to different slopes and, combined with the maximum actual swimming distance of fish upstream observed in fish release experiments, constructs a predictive model of the upstream distance and success rate of experimental fish under various flow conditions (corresponding to different fishway slopes) through comprehensive data analysis. This model can provide a reference for adjusting the slope plate threshold in this invention. Attached Figure Description

[0021] Figure 1 This is a detailed view of the fish passage outlet of the present invention; Figure 2 This is a detailed longitudinal section view of the fishway outlet and the variable slope plate of the present invention; Figure 3 This is a schematic diagram of the variable slope plate and the flow-blocking arrangement of the present invention; Figure 4 This is a schematic diagram of the arrangement of the float plate at the fishway outlet of the present invention; Figure 5 This is a schematic diagram of the structure of the spring telescopic rod of the present invention; Figure 6 This is a schematic diagram of the structure of the hydraulic telescopic rod of the present invention; Figure 7 This is a schematic diagram of the fluid-blocking device configuration of the present invention; Figure 8 This is a schematic diagram of the resting area formed by the fluid resistance of the present invention; Figure 9 This is a top view of the structure of the present invention; Figure 10 This is a schematic diagram of the invention at the dam; Figure 11 This is a schematic diagram of the fishway outlet slope change during the rise and fall of the reservoir water level in the structure of the present invention. Figure 12 This invention relates to a predictive model for the upstream distance and success rate of experimental fish. Figure 13 This is the experimental test area layout diagram in Table 1 of this invention.

[0022] In the diagram: 1-Fishway, 101-Fishway outlet, 102-Fishway sidewall, 103-Fishway bottom plate, 104-Fishway inlet, 105-Baffle, 2-Float plate, 201-Support rod, 202-Buffer pad, 203-Float plate rotation shaft, 204-Water level elevation sensor, 3-Water inlet, 4-Telescopic rod, 41-Spring telescopic rod, 42-Hydraulic telescopic rod, 401-Height limiting spring, 402-Hydraulic rod, 4021-Motor control system, 403-Bottom rod, 4 04-Upper rod, 5-Adjustment unit, 51-Guide channel, 52-Plate shaft, 501-First slope plate, 5011-Restriction block, 502-Second slope plate, 503-Third slope plate, 504-Fourth slope plate, 505-First fixed plate, 506-Second fixed plate, 6-Flow obstruction, 601-Rest area, I-Energy dissipation and rectification grid, II-Water flow gradient zone, III-Test zone, IV-Adaptation zone, V-Downstream barrier, VI-Tail gate, VII-Trapezoidal obstacle. Detailed Implementation

[0023] The technical solution of the present invention is further described below, but the scope of protection is not limited to what is described.

[0024] Example: This embodiment describes two processes of actual water level rise and fall in the reservoir area of ​​a certain water conservancy and hydropower project on a certain day. The water level rises from low to high from 2600m to 2602m, and then from 2602m to 2604m; the water level falls from high to low from 2604m to 2602m, and then from 2602m to 2600m. The water level range corresponding to the fish passage season is 2600~2604m, as detailed below. Figure 11 As shown.

[0025] like Figures 1 to 13 As shown, a floating fishway outlet structure adapted to the fluctuation of water level in a reservoir includes a fishway outlet 101, which is connected to one end of a fishway 1 located in the reservoir. The other end of the fishway 1 is provided with a fishway inlet 104. An adjustment unit 5 is provided inside the fishway outlet 101, and a floating plate 2 is hinged to the adjustment unit 5. The floating plate 2 is located outside the outlet end of the fishway outlet 101 and has elasticity and extensibility, moving with the fluctuation of water level in the reservoir. The adjustment unit 5 is slidably connected to the fishway outlet 101, and a telescopic rod 4 is provided at the bottom of the adjustment unit 5. The bottom of the telescopic rod 4 is connected to the fishway outlet 101.

[0026] The fishway outlet 101 includes a fishway sidewall 102 and a fishway bottom plate 103. The fishway bottom plate 103 is vertically arranged on both sides of the fishway sidewall 102. The float plate 2 is hinged to the fishway sidewall 102 and the adjustment unit 5 on both sides via a float plate rotation shaft 203. The telescopic rod 4 is connected to the fishway bottom plate 103. The two sides of the float plate rotation shaft 203 are slidably connected to the fishway sidewall 102 within the guide channel 51, thus restricting the range and direction of movement of the float plate 2.

[0027] Support rods 204 are installed on the outer wall of the fishway sidewall 102, and buffer pads 202 are installed on the support rods 204. A guide channel 51 is installed on the inner wall of the fishway bottom plate 103, and a limiting block 5011 is installed within the guide channel 51. The guide channel 51 is parallel to the height direction of the fishway bottom plate 103. The limiting block 5011 ensures that during the overall vertical movement of each slope plate, the slope of each slope plate does not exceed the slope corresponding to the maximum flow-controlling capacity of the fish inside the fishway outlet 101.

[0028] When the water level continues to drop below 2600m, the entire fish passage season is completed, and the fish passage 1 ceases to operate. At this time, the float plate 2 will automatically fall counterclockwise along the float plate rotation axis 203 under its own weight to the support rod 201 fixed on the side wall 102 of the fish passage. The buffer pad 202 attached to the end of the support rod 201 can buffer the counterclockwise rotation force of the float plate 2 under the action of gravity.

[0029] A baffle 105 is provided at one end of the fishway bottom plate 103 near the float plate 2, and a water inlet hole 3 is provided on the baffle 105.

[0030] A water level elevation sensor 204 is installed on the floating plate 2. The water level elevation sensor 204 complements the water level sensor installed on the bottom rod 403, so that if one sensor fails, the water level can still be sensed by the other sensor.

[0031] The telescopic rod 4 includes a bottom rod 403, an upper rod 404, and a middle section. The bottom rod 403 is connected to the upper rod 404 through the middle section. The bottom rod 403 is connected to the fishway bottom plate 103. A water level sensor is provided on the surface of the bottom rod 403.

[0032] The middle section includes either a hydraulic spring telescopic rod 41 or a hydraulic telescopic rod 42. The choice of either hydraulic spring telescopic rod 41 or hydraulic telescopic rod 42 can be made according to the actual needs of the project. Hydraulic spring telescopic rod 41 can be used when the water flow is rapid to increase overall stability, while hydraulic telescopic rod 42 can be used when the water flow is slow, thus reducing operating costs. The spring telescopic rod 41 includes a hydraulic rod 402, a height-limiting spring 401, and a motor control system 4021. The height-limiting spring 401 is mounted on the hydraulic rod 402. The hydraulic telescopic rod 42 includes a hydraulic rod 402 and a motor control system 4021.

[0033] The adjustment unit 5 includes a slope-changing plate assembly, a first fixing plate 505, and a second fixing plate 506. One end of the first fixing plate 505 is hinged to the slope-changing plate assembly, and the other end of the first fixing plate 505 is hinged to the second fixing plate 506. Obstruction fluids 6 are respectively provided on the slope-changing plate assembly, the first fixing plate 505, and the second fixing plate 506. The first fixing plate 505 is horizontally positioned, and the slope i of the second fixing plate 506 is 2%. The slope i is between 2% and 4%, and the horizontal length L is less than or equal to the maximum swimming distance of the fish. One end of the second fixing plate 506 is connected to the fishway 1. The obstruction fluids 6 can be configured as follows: the upstream side is arc-shaped or the entire surface is flat. The obstruction fluids 6 are arranged parallel or alternately.

[0034] During the rise of the reservoir water level, the inflow elevation of the fishway outlet 101 is controlled by relying on the buoyancy of the floating plate 2. During the water level adjustment, the slope of each variable slope plate changes, resulting in complex flow conditions. Therefore, it is necessary to set up a flow barrier 6 that is deeper than the inflow. Based on the flow blocking and flow obstruction effect below the flow barrier 6, a fish resting area 601 is formed on the back surface of the flow barrier 6. The resting area 601 can provide space for fish to recover their strength during the upstream process, and also provide time for fish to recover their strength as they pass through the fishway outlet 101.

[0035] The variable slope plate assembly includes a first variable slope plate 501, a second variable slope plate 502, a third variable slope plate 503, and a fourth variable slope plate 504 that are hinged together in sequence. A plate shaft 52 is provided between the first variable slope plate 501, the second variable slope plate 502, the third variable slope plate 503, and the fourth variable slope plate 504 to achieve hinge connection. The bottom of the plate shaft 52 is connected to a telescopic rod 4, and the plate shaft 52 is slidably connected to the fishway bottom plate 103 through a guide channel 51.

[0036] Specifically, the telescopic rod 4 connected by the plate shaft 52 between the first slope plate 501 and the second slope plate 502 is telescopic rod number 1; the telescopic rod 4 connected by the plate shaft 52 between the second slope plate 502 and the third slope plate 503 is telescopic rod number 2; and the telescopic rod 4 connected by the plate shaft 52 between the third slope plate 503 and the fourth slope plate 504 is telescopic rod number 3. Since each slope plate is adjustable in slope, its structural characteristics can be set to a certain degree of elasticity, allowing for elongation and telescopic movement.

[0037] A method for adjusting the outlet structure of a floating fishway to adapt to changes in reservoir water level includes the following steps: S1: By constructing an upward distance-success rate mathematical model, the length and slope of the first slope plate 501, the second slope plate 502, the third slope plate 503 and the fourth slope plate 504 are set according to the upward distance-success rate mathematical model. S2: When the water level in the reservoir rises from 2600m to 2602m, the fishway outlet 101 of fishway 1 needs to switch its operating mode. The buoyancy of the water drives the floating plate 2 and the first slope plate 501 to rise. The first slope plate 501 drives the second slope plate 502, the third slope plate 503 and the fourth slope plate 504 to rise. Water enters the fishway outlet 101 from the inlet hole 3, so that the bottom plate 103 of the fishway has a suitable water depth for fish to swim upstream to the fishway outlet 101. When the water submerges the water level sensor installed on the bottom rod 403, the water level elevation sensing signal 204 and the water level sensor transmit the sensed signal to the motor control system 4021 of the telescopic rod 4, so that the middle section starts to work. The telescopic rod 4 controls the angle of the first slope plate 501, the second slope plate 502, the third slope plate 503 and the fourth slope plate 504 to the required range suitable for the water force characteristics of fish swimming upstream. The adjustment method for the process of the reservoir water level rising from 2602m to 2604m is the same as step S2; S3: As the reservoir water level drops from 2604m to 2602m, the floating plate 2 and the first slope plate 501 descend with the water level. The first slope plate 501 drives the second slope plate 502, the third slope plate 503 and the fourth slope plate 504 to descend. The water level elevation sensing signal 204 and the water level sensor installed on the bottom rod 403 detect the water level and transmit the signal to the motor control system 4021 of the telescopic rod 4, so that the middle section starts to work, and the telescopic rod 4 controls the angle of the first slope plate 501, the second slope plate 502, the third slope plate 503 and the fourth slope plate 504 to the required range through extension and retraction. The adjustment method for the process of lowering the reservoir water level from 2602m to 2600m is the same as in step S3.

[0038] This embodiment features a four-stage slope-changing plate system, primarily designed to gradually transition the water flow from the fishway outlet 101 section towards the downstream interior of fishway 1, ultimately ensuring a smooth transition to the first fixed plate 505 and the second fixed plate 506 with a normal downstream slope. The system is not limited to four slope-changing plates; if the fish's ability to withstand the current is weak, more slope-changing plates can be added appropriately. This invention is mainly targeted at hydropower stations in the high-altitude, high-water-level-variable areas of the southwest canyon region.

[0039] Since the elevation of the fishway outlet needs to be determined based on the hydrological relationship and water level fluctuation of the reservoir area, in this embodiment of the project, the water level fluctuation of the reservoir area is 4m. When the water level rises by more than 2m, the slope of the first slope plate 501, the second slope plate 502, the third slope plate 503 and the fourth slope plate 504 need to be switched.

[0040] Changes in fishways primarily alter the flow velocity within them. When the fishway slope is steep, the flow velocity is relatively high; conversely, when the slope is gentle, the flow velocity is relatively low. Based on this, this invention establishes a mathematical model of upstream distance versus success rate, setting corresponding water flow velocities for different slope gradients. This model provides a reference for adjusting the length and slope thresholds of the variable slopes in this invention.

[0041] Table 1. Experimental conditions for fish traversing upstream under different flow rates (different slopes are converted to flow rates).

[0042] Based on the applicant's existing research findings on this reservoir area (the results are unpublished), the maximum upstream migration distance of fish in this reservoir area is 6.26m. The open flume behavior testing area was selected as the research area for this chapter. Figure 13 As shown. The experimental area is divided into an energy dissipation and rectification grid I, a flow gradient zone II, a test zone III, an adaptation zone IV, a downstream barrier V, a tailgate VI, and a single trapezoidal obstacle VII. To reduce turbulence before the water enters the trapezoidal obstacle, a flow gradient zone II is set up before the inlet of the trapezoidal obstacle. The length of flow gradient zone II is approximately 26 cm. The length * width * height dimensions of test zone III are 600 cm * 15 cm * 30 cm. Test zone III is divided into three locations: the upstream water inlet, the middle (2.22~3.02 m along the water flow direction), and the downstream water outlet. Top-down and side-down monitoring systems are set up at each of the three locations. The length * width * height dimensions of adaptation zone IV before the fish release experiment are 20 cm * 30 cm * 30 cm. To ensure that the experimental fish can choose different water layers to swim upstream at sufficient water depth, the average water depth in the open tank is set to 20~24 cm. The experiment consisted of five working conditions, representing different slopes (i=2, 2.5, 3, 3.5, 4%). The average inlet flow velocity (average water depth) for the five working conditions were 0.42 m / s (24 cm), 0.65 m / s (23 cm), 0.85 m / s (22.5 cm), 1.02 m / s (24 cm), and 1.24 m / s (23 cm), respectively. Approximately 25 fish of each species were tested under each flow velocity condition.

[0043] The formula for calculating the backtracking distance-success rate mathematical model is as follows: In the formula, Success rate; Upward distance under various operating conditions; , These are factor coefficients; This is the distance coefficient; This represents the distance count.

[0044] Table 2. Weighting coefficients of various components in the mathematical model of uplink distance-success rate.

[0045] In Tables 1 and 2, the change in slope is equivalent to the change in water flow velocity. Preliminary experiments show that: Condition 1: When the water flow rate entering the open channel is 22 L / s, it is relatively close to the non-mainstream flow velocity conditions under a 2% fishway slope; Condition 2: When the water flow rate entering the open channel is 35 L / s, it is relatively close to the non-mainstream flow velocity conditions under a 2.5% fishway slope; Condition 3: When the water flow rate entering the open channel is 54 L / s, it is relatively close to the non-mainstream flow velocity conditions under a 3% fishway slope; Condition 4: When the water flow rate entering the open channel is 72 L / s, it is relatively close to the non-mainstream flow velocity conditions under a 3.5% fishway slope; Condition 5: When the water flow rate entering the open channel is 83 L / s, it is relatively close to the non-mainstream flow velocity conditions under a 4% fishway slope. Coefficient of determination (R) 2 The value of 1 is used to measure the goodness of fit of a model. The closer the value is to 1, the better the fit, and thus the more algebraically applicable the model can be directly applied.

[0046] This invention transforms the study of fishway slope parameters into the study of their direct hydraulic effects (flow velocity). The basis for this is that, for a fishway with a defined cross-sectional shape and roughness, under conditions of uniform or near-uniform flow, its bottom slope (i.e., physical slope) is numerically equivalent to the hydraulic slope, and is the controlling factor determining the average flow velocity and flow pattern distribution within the channel. Therefore, adjusting the fishway slope essentially results in changing the flow velocity. Based on the general laws of fish behavior, fish's upstream decision-making, swimming behavior, and passage probability are direct biological outputs of their perception and response to the local hydrodynamic environment (such as instantaneous flow velocity, gradient, and turbulence intensity), rather than responses to geometric slope. To directly establish a quantitative model between fish's ability to withstand flow and key hydraulic factors, and to avoid interference from complex structural coupling analysis, the experimental design of this invention adopts the research path of equivalent hydraulic condition simulation. By precisely controlling the inflow conditions in an indoor standard fish behavior observation tank, a series of stable and spatially representative velocity fields are generated. This systematic velocity condition is essentially equivalent to the key water flow scenarios that may be formed in actual fish passages with different design slopes, posing challenges to fish.

[0047] Therefore, the experiments of this invention generate a series of stable, spatially representative velocity fields by precisely controlling the flow rate in a standard tank and the inflow conditions in an indoor standard fish behavior observation tank. These velocity fields are systematically equivalent to the key water flow scenarios generated in actual fishways with different designed slopes. The research path provided in this invention focuses on the biomechanical nature of the "fish-water flow" interaction, enabling experimental data to be directly used to verify the fish upstream success rate prediction model, thereby ensuring the logical rigor from structural parameters to biological effect prediction.

[0048] The optimal setting angle of each slope plate needs to be determined based on the actual engineering situation and in conjunction with hydraulic experiments, so that the fishway 1 can achieve the optimal hydraulic conditions for fish to swim upstream. The setting angles of each slope plate in this embodiment at different water levels are shown in Tables 3 and 4.

[0049] Table 3. Statistics of the length of the telescopic rods corresponding to the setting angle of each slope plate in this embodiment of the project when the reservoir water level rises from 2600m to 2602m.

[0050] Table 4 provides the lengths of the telescopic rods corresponding to the installation angles of each slope plate in this embodiment of the project, assuming the reservoir water level rises from 2602m to 2604m.

Claims

1. A floating fishway outlet structure adaptable to varying reservoir water levels, characterized in that: It includes a fish passage outlet (101), which is connected to one end of the fish passage (1) in the reservoir area. The other end of the fish passage (1) is provided with a fish passage inlet (104). An adjustment unit (5) is provided inside the fish passage outlet (101). A floating plate (2) is hinged on the adjustment unit (5). The floating plate (2) is located outside the outlet end of the fish passage outlet (101). The adjustment unit (5) is slidably connected to the fish passage outlet (101). A telescopic rod (4) is provided at the bottom of the adjustment unit (5). The bottom of the telescopic rod (4) is connected to the fish passage outlet (101).

2. The floating fishway outlet structure adaptable to reservoir water level fluctuations as described in claim 1, characterized in that: The fish passage outlet (101) includes a fish passage side wall (102) and a fish passage bottom plate (103). The fish passage bottom plate (103) is vertically arranged on both sides of the fish passage side wall (102). The float plate (2) is hinged to the fish passage side walls (102) on both sides and the adjustment unit (5) through the float plate rotation shaft (203). The telescopic rod (4) is connected to the fish passage bottom plate (103).

3. The floating fishway outlet structure adaptable to reservoir water level fluctuations as described in claim 2, characterized in that: The outer wall of the fishway sidewall (102) is provided with a support rod (204), and a buffer pad (202) is provided on the support rod (204). The inner wall of the fishway bottom plate (103) is provided with a guide channel (51), and a limiting block (5011) is provided in the guide channel (51).

4. The floating fishway outlet structure adaptable to reservoir water level fluctuations as described in claim 2, characterized in that: The bottom plate (103) of the fish passage is provided with a baffle (105) at one end near the floating plate (2), and the baffle (105) is provided with a water inlet hole (3).

5. The floating fishway outlet structure adaptable to reservoir water level fluctuations as described in claim 1, characterized in that: A water level elevation sensing signal (204) is installed on the floating plate (2).

6. The floating fishway outlet structure adaptable to reservoir water level fluctuations as described in claim 1, characterized in that: The telescopic rod (4) includes a bottom rod (403), an upper rod (404) and a middle section. The bottom rod (403) is connected to the upper rod (404) through the middle section. A water level sensor is provided on the surface of the bottom rod (403).

7. The floating fishway outlet structure adaptable to reservoir water level fluctuations as described in claim 6, characterized in that: The middle section includes a hydraulic spring telescopic rod (41) or a hydraulic telescopic rod (42). The spring telescopic rod (41) includes a hydraulic rod (402), a height limiting spring (401), and a motor control system (4021). The height limiting spring (401) is mounted on the hydraulic rod (402). The hydraulic telescopic rod (42) includes a hydraulic rod (402) and a motor control system (4021).

8. The floating fishway outlet structure adaptable to reservoir water level fluctuations as described in claim 1, characterized in that: The adjustment unit (5) includes a slope plate assembly, a first fixing plate (505) and a second fixing plate (506). One end of the first fixing plate (505) is hinged to the slope plate assembly, and the other end of the first fixing plate (505) is hinged to the second fixing plate (506). The slope plate assembly, the first fixing plate (505) and the second fixing plate (506) are respectively provided with flow-blocking fluids (6).

9. The floating fishway outlet structure adaptable to reservoir water level fluctuations as described in claim 8, characterized in that: The variable slope plate assembly includes a first variable slope plate (501), a second variable slope plate (502), a third variable slope plate (503), and a fourth variable slope plate (504) that are hinged together in sequence. A plate shaft (52) is provided between the first variable slope plate (501), the second variable slope plate (502), the third variable slope plate (503), and the fourth variable slope plate (504) to achieve hinge connection. The bottom of the plate shaft (52) is connected to a telescopic rod (4). The plate shaft (52) is slidably connected to the fishway bottom plate (103) through a guide channel (51).

10. A method for adjusting the outlet structure of a floating fishway adapted to reservoir water level fluctuations as described in any one of claims 1-9, characterized in that, Includes the following steps: S1: By constructing the mathematical model of tracing distance-success rate, the lengths of the first slope plate (501), the second slope plate (502), the third slope plate (503) and the fourth slope plate (504) are set according to the mathematical model of tracing distance-success rate; S2: As the water level in the reservoir rises, the buoyancy of the water causes the floating plate (2) and the first slope plate (501) to rise. The first slope plate (501) causes the second slope plate (502), the third slope plate (503) and the fourth slope plate (504) to rise. The water enters the fish passage outlet (101) from the inlet hole (3). When the water submerges the water level sensor installed on the bottom rod (403), the water level elevation sensing signal device (204) and the water level sensor transmit the sensed signal to the motor control system (4021) of the telescopic rod (4), so that the middle section starts to work, and the telescopic rod (4) controls the angle of the first slope plate (501), the second slope plate (502), the third slope plate (503) and the fourth slope plate (504) to the required range through extension and retraction. S3: When the water level in the reservoir drops, the floating plate (2) and the first slope plate (501) drop with the water level. The first slope plate (501) drives the second slope plate (502), the third slope plate (503) and the fourth slope plate (504) to drop. The water level elevation sensing signal (204) and the water level sensor installed on the bottom rod (403) detect the water level and transmit the signal to the motor control system (4021) of the telescopic rod (4), so that the middle section starts to work, and the telescopic rod (4) controls the angle of the first slope plate (501), the second slope plate (502), the third slope plate (503) and the fourth slope plate (504) to the required range through extension and retraction.

11. The method for adjusting the floating fishway outlet structure adapted to reservoir water level fluctuations as described in claim 10, characterized in that: The calculation formula for the aforementioned uplink distance-success rate mathematical model is as follows: In the formula, Success rate; Upward distance under various operating conditions; , These are factor coefficients; This is the distance coefficient; This represents the distance count.

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