A gate control hub regulation method suitable for multi-target fish up-and-down migration

Abstract

A kind of control method of gate control hub suitable for multi-target fish up-and-down migration, comprising: determining the flow velocity suitability curve suitable for multi-target adult fish and juvenile fish;Carrying out numerical simulation of flow field under different discharge conditions of gate control engineering, to obtain the upstream and downstream flow field of each representative working condition;According to the flow velocity suitability curve of adult fish and juvenile fish determined, the upstream and downstream flow field of each representative working condition obtained is evaluated for flow velocity suitability, and the migration channel of adult fish up-and-down and juvenile fish down-and-up is predicted according to the evaluation result of flow velocity suitability;According to the migration channel of adult fish up-and-down and juvenile fish down-and-up predicted, if the migration channel is discontinuous, compare the size relationship between the flow velocity of discontinuous region and the swimming ability of fish, and change the gate opening mode under the condition that the discharge is unchanged.The present application proposes a gate control hub control method based on the prediction of adult fish up-and-down and juvenile fish down-and-up migration channel suitable for the swimming ability of adult fish and juvenile fish, which can meet the demand of fish bidirectional migration and provide technical support for aquatic ecological protection.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of ecological water conservancy, and particularly relates to a gate control hub regulation method suitable for up-and-down migration of multi-target fish. BACKGROUND

[0002] The gate control hub project built on a river affects the connectivity of the river, and the migratory fish has the demand of bidirectional migration of up-migration of adult fish to the river to spawn and down-migration of juvenile fish to the lake to feed, and it is particularly important to restore the up-and-down migration channel blocked by the gate dam for the migratory fish.

[0003] The existing fish up-migration technology includes fishway, fish elevator, natural channel simulation, fish lock and the like. The adult fish can successfully up-migrate by using the fishway, but due to the difference in behavior characteristics between the juvenile fish and the adult fish, the upstream flow inlet of the fishway is difficult to attract the down-migrating juvenile fish, resulting in that the fishway and other fish passing facilities are not suitable for the down-migration of the juvenile fish. The existing fish down-migration technology includes water turbine, spillway, down-migration bypass system, fish collecting technology and the like, and these down-migration facilities have certain effects on the down-migration of the fish, but also have shortcomings in safety and adaptability and the like.

[0004] Most of the previous studies focus on the blocking effect of the power generation hub on the up-migration channel of the adult fish, the flow velocity suitability of different flow conditions of the power station is evaluated, the up-migration channel suitable for multi-target adult fish is predicted according to the evaluation results, and the inlet arrangement of the fishway and the optimization suggestion of the operation and scheduling of the power station are proposed. The previous studies have two shortcomings, one is that only the connectivity of the up-migration channel of the adult fish is considered, and the connectivity of the down-migration channel of the juvenile fish is not concerned; the other is that the fish migration channel of the gate control hub is not analyzed, and the gate control hub only relies on the gate water release, and its regulation method is different from that of the power generation hub. At present, under the premise of adapting to the swimming ability of the adult fish and the juvenile fish, the technology of improving the connectivity of the up-and-down migration channel of the fish by using the gate control hub regulation method is almost not available. SUMMARY

[0005] The present application fills the blank in the field of bidirectional fish passing channel of the gate control hub, forms the gate control hub regulation method suitable for the swimming ability of the adult fish and the juvenile fish by predicting the up-migration channel of the adult fish and the down-migration channel of the juvenile fish, and solves the demand of bidirectional migration of the fish under the premise of not additionally building the down-migration bypass, thereby providing technical support for the water ecological protection work.

[0006] To achieve the above object, the technical scheme of the present application is as follows:

[0007] A kind of control method of dam control hub suitable for multi-target fish up-and-down migration, the purpose of the construction of the dam control hub is to regulate river water level in dry season, adopts the operation mode of regulating dry not flood, dam control hub includes sluice, fishway, the sluice adopts aerodynamic shield-shaped gate, gate opening is adjusted between 0 and 1, the inlet of the fishway is located in the shore side below gate, and the discharge of gate close to the shore provides fish flow conditions for the inlet of its fishway, the method includes the following steps:

[0008] Step S1: determine the flow velocity suitability curve suitable for multi-target adult fish and juvenile fish;

[0009] Step S2: carry out numerical simulation of flow field under different flow conditions of dam control project, obtain the upstream and downstream flow field of each representative working condition;

[0010] Step S3: according to the flow velocity suitability curve of adult fish and juvenile fish determined in step S1, the upstream and downstream flow field of each representative working condition obtained in step S2 is evaluated, and the migration channel of adult fish up-and-down and juvenile fish down-and-up is predicted according to the evaluation result of flow velocity suitability;

[0011] Step S4: according to the migration channel of adult fish up-and-down and juvenile fish down-and-up predicted in step S3, if the migration channel is discontinuous, compare the size relationship between the flow rate of discontinuous area and the swimming ability of fish, and change the gate opening mode under the condition that the discharge is unchanged.

[0012] Further, the step S1 includes:

[0013] S11: obtain the body length of multi-target fish passing objects adult fish and juvenile fish in the river section where the dam control hub project is located;

[0014] S12: obtain the swimming ability data corresponding to the body length of adult fish and juvenile fish, including induced flow rate, critical swimming speed and burst swimming speed;

[0015] S13: define the region with flow rate less than induced flow rate as non-perception zone, i.e.U i ; define the region with flow rate range between induced flow rate and 0.5 times critical swimming speed as induced zone, i.e.U i ≤U<0.5U c ; define the region with flow rate range between 0.5 times critical swimming speed and critical swimming speed as preferred zone, i.e.0.5U c ≤U≤U c ; define the region with flow rate range between critical swimming speed and burst swimming speed as burst zone, i.e.U c <U≤U b ; define the region with flow rate greater than burst swimming speed as barrier zone, i.e.U>U b ;

[0016] S14: defining a dimensionless flow velocity suitability index VSI representing the suitability of flow velocity for the migration of adult fish and juvenile fish, with a suitability of 0 indicating that the flow velocity in the region is unsuitable for fish migration, and a suitability of 1 indicating that the flow velocity in the region is most suitable for fish migration, the flow velocity suitability score being 0 in the non-perception zone and the barrier zone, and the flow velocity suitability score being 1 in the preferred zone;

[0017] S15: when U i , VSI = 0; when U i ≤ U < 0.5U c , VSI = (U-U i ) / (0.5U c -U i ); when 0.5U c ≤ U ≤ U c , VSI = 1; when U c < U ≤ U b , VSI = (U-U b ) / (U c -U b ); when U > U b , VSI = 0;

[0018] S15: when U i , VSI = 0; when U i ≤ U < 0.5U c , VSI = (U-U i ) / (0.5U c -U i ); when 0.5U c ≤ U ≤ U c , VSI = 1; when U c < U ≤ U b , VSI = (U-U b ) / (U c -U b ); when U > U b , VSI = 0;

[0019] S16: based on the perception flow velocity, the critical swimming velocity and the burst swimming velocity of adult fish and juvenile fish obtained in step S12, and the segmented flow velocity suitability index defined in step S15, the flow velocity suitability curves of adult fish and juvenile fish are respectively established.

[0020] Further, the fish body length in step S11 is obtained by collecting the fish resource survey results of the river section in the literature, and the representative body length of adult fish and juvenile fish is selected by taking a smaller value in the range of body length, and the representative body length of multiple fish is selected for adult fish and juvenile fish respectively.

[0021] Further, the perception flow velocity U i in step S13 is the minimum value of the perception flow velocities of multiple fish, the critical swimming velocity U c is the minimum value of the critical swimming velocities of multiple fish, and the burst swimming velocity U b is the maximum value of the burst swimming velocities of multiple fish.

[0022] Further, the step S2 comprises:

[0023] S21: a two-dimensional or three-dimensional mathematical model of the upper and lower long river sections of the gate control hub is established to simulate the flow field numerical value of the gate control project, and the simulation range includes the upper river section, the sluice and the lower river section;

[0024] S22: the mathematical model in step S21 is verified;

[0025] S23: According to the control operation scheme of the gate control hub, representative flow is selected to prepare a calculation working condition;

[0026] S24: The upstream and downstream flow fields of each working condition are calculated to obtain hydraulic characteristics, including flow velocity, flow direction and water depth.

[0027] Further, the mathematical model in step S21 can simulate the discharge under different gate opening conditions.

[0028] Further, step S22 verifies the reliability of the mathematical model by using the hydraulic parameters obtained from the physical model test of the same gate control hub.

[0029] Further, the step S3 comprises:

[0030] S31: According to the flow velocity suitability curve of adult fish and juvenile fish prepared in step S1, the upstream and downstream flow fields of each representative working condition obtained in step S2 are evaluated in terms of flow velocity suitability, so as to obtain the flow velocity suitability distribution of the adult fish upriver and the juvenile fish downriver under each representative working condition;

[0031] S32: Select the flow velocity suitability index 0.4-1.0 as the suitable migration channel for fish, and use it to predict the migration channel of adult fish upriver and juvenile fish downriver, wherein the adult fish upriver migration channel includes two types, one is that the adult fish migrates from the downstream natural river to the fishway inlet and passes through the fishway upriver, and the other is that the adult fish migrates from the downstream natural river to the open gate and passes through the fully open gate upriver; The juvenile fish downriver migration channel of the gate control hub refers to the juvenile fish migrating from the upstream natural river to the open gate and passing through the gate top overflow to flow downriver.

[0032] Further, the step S4 comprises:

[0033] S41: Identify the connectivity of the adult fish upriver and juvenile fish downriver migration channel under each representative working condition, and when the migration channel is discontinuous, the gate opening mode needs to be changed under the condition that the discharge remains unchanged, specifically:

[0034] S42: When the upriver migration channel is discontinuous, if the flow velocity in the discontinuous region is close to the adult fish burst swimming speed, the opening of the gate at the corresponding position on the flow line in the region is reduced, and if the flow velocity in the discontinuous region is close to the adult fish induced flow velocity, the opening of the gate at the corresponding position on the flow line in the region is increased.

[0035] S43: When the downriver migration channel is discontinuous, if the flow velocity in the discontinuous region is close to the juvenile fish burst swimming speed, the opening of the gate at the corresponding position on the flow line in the region is reduced, and if the flow velocity in the discontinuous region is close to the juvenile fish induced flow velocity, the opening of the gate at the corresponding position on the flow line in the region is increased.

[0036] S44: After adjusting the gate opening, the connectivity of the up-migration and down-migration channels of the working condition is re-predicted according to steps S2 and S3 until the up-migration and down-migration channels are both continuous.

[0037] Further, the up-migration channel connectivity judgment standard in step S41 is: from the downstream river to the fishway inlet or the fully open gate, if there is a continuous uninterrupted migration channel with a width of more than twice the fish body, it indicates that the up-migration channel of the adult fish is continuous, otherwise it is not continuous; the down-migration channel connectivity judgment standard is: from the upstream river to the open gate, if there is a continuous uninterrupted migration channel with a width of more than twice the fish body, it indicates that the down-migration channel of the juvenile fish is continuous, otherwise it is not continuous.

[0038] The beneficial effects of the present application are:

[0039] 1. The flow velocity suitability curve suitable for multi-target adult fish and juvenile fish proposed by the present application fully considers the swimming ability of adult fish and juvenile fish, and avoids the water flow barrier of the fishway or the inability to sense the migration direction during the migration process of fish.

[0040] 2. The up-migration and down-migration channels predicted based on the flow velocity suitability curve quantitatively predict the position of the migration channel, provide a reference for the arrangement and operation of the auxiliary fish passing device such as the fish blocking grid, and further improve the effect of two-way fish passing.

[0041] 3. The gate control hub regulation method suitable for multi-target fish up-migration and down-migration proposed by the present application optimizes the connectivity of the up-migration and down-migration channels of fish by changing the gate opening mode, compared with the up-migration fish passing facility such as the fishway, meets the two-way migration demand of adult fish up-migration spawning and reproduction and juvenile fish down-migration feeding and fattening in the river section arranged by the gate control hub, and has the advantages of simplicity, efficiency and the like. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 The flow chart of one embodiment of the gate control hub regulation method suitable for multi-target fish up-migration and down-migration of the present application;

[0043] Figure 2 The schematic diagram of the planar arrangement of the gate control hub of the embodiment;

[0044] Figure 3 The schematic diagram of the pneumatic shield gate;

[0045] Figure 4 The flow velocity suitability curve suitable for adult fish up-migration and juvenile fish down-migration;

[0046] Figure 5 The two-dimensional mathematical model of the gate control hub upstream and downstream long river section;

[0047] Figure 6The flow velocity partition result of the adaptation of adult fish up-migration and juvenile fish down-migration for a typical working condition;

[0048] Figure 7 The migration channel prediction result of adult fish up-migration and juvenile fish down-migration for a typical working condition;

[0049] Figure 8 The flow velocity partition result of the adaptation of adult fish up-migration and juvenile fish down-migration after regulating the opening mode of the gate for a typical working condition;

[0050] Figure 9 The migration channel prediction result of adult fish up-migration and juvenile fish down-migration after regulating the opening mode of the gate for a typical working condition. DETAILED DESCRIPTION

[0051] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0052] The present application provides a gate control hub regulation method for adapting multi-target fish up-and-down migration, and the steps are as shown in Figure 1 The gate control hub in the embodiments mainly comprises 20-hole sluices, fishways and connecting sections and the like, as shown in Figure 2 The hub project adopts a regulation scheme of regulating in dry season but not in flood season. The sluices all adopt pneumatic shield gates, and the gates can be adjusted according to any opening degree, as shown in Figure 3 The fishway is located on the left bank of the hub, the fishway inlet is located at the bank 80 meters downstream of the No. 1 sluice, and the fishway outlet is located at the bank 250 meters upstream of the No. 1 sluice. The water flow discharged by the sluices provides fish-attracting water flow conditions for the fishway inlet.

[0053] The present application provides a gate control hub regulation method for adapting multi-target fish up-and-down migration, and the steps are as shown in Figure 1 The present application provides a gate control hub regulation method for adapting multi-target fish up-and-down migration, and the steps are as shown in

[0054] Step S1: determining a flow velocity suitability curve suitable for multi-target adult fish and juvenile fish, comprising the following steps:

[0055] S11: Obtain the multi-objective fish migration objects of the river section where the gate hub project is located, the fish migration objects are the four major Chinese carps, grass carp, silver carp, and bighead carp; obtain the body length of the juvenile fish and adult fish of the fish migration objects, the representative body length of the adult fish is 20 cm, and the representative body length of the juvenile fish is 10 cm. The fish migration objects and fish body length data in step S11 can be obtained by collecting the fish resources investigation results of the river section in the literature. In order to ensure that fish with migration requirements can migrate smoothly, the principle of selecting the representative body length of the adult fish and juvenile fish is to select the smaller value in the body length range, and the representative body length of the adult fish and juvenile fish of the multi-objective fish migration objects is selected.

[0056] S12: Select the induced flow velocity U i , the critical swimming speed U c , and the burst swimming speed U b measured under the conditions of a test temperature of 20℃, a body length of 20 cm, and a body length of 10 cm to represent the swimming ability of the adult fish and juvenile fish of the four major Chinese carps, as shown in Table 1.

[0057] Table 1 Swimming ability of adult fish and juvenile fish of the four major Chinese carps

[0058]

[0059] The swimming ability data in step S12 refers to the induced flow velocity, the critical swimming speed, and the burst swimming speed matched with the representative body length of the adult fish and juvenile fish obtained from the literature. Generally, the relative swimming speed decreases with the increase of the body length, and the absolute swimming speed increases with the increase of the body length, so it is very important to select the swimming ability data corresponding to the body length.

[0060] S13: Define the region with a flow velocity less than the induced flow velocity as the non-perception zone, i.e. U i ; define the region with a flow velocity ranging from the induced flow velocity to 0.5 times the critical swimming speed as the induced zone, i.e. U i ≤ U < 0.5 U c ; define the region with a flow velocity ranging from 0.5 times the critical swimming speed to the critical swimming speed as the preferred zone, i.e. 0.5 U c ≤ U ≤ U c ; define the region with a flow velocity ranging from the critical swimming speed to the burst swimming speed as the burst zone, i.e. U c ≤ U ≤ U b ; and define the region with a flow velocity greater than the burst swimming speed as the barrier zone, i.e. U > U b .

[0061] S14: Define the dimensionless flow velocity suitability index VSI to represent the suitability of the flow velocity for the migration of the adult fish and juvenile fish, a suitability of 0 indicates that the flow velocity in the region is not suitable for fish migration, and a suitability of 1 indicates that the flow velocity in the region is most suitable for fish migration, the flow velocity suitability score of the non-perception zone and the barrier zone is 0, and the flow velocity suitability score of the preferred zone is 1.

[0062] S15: When U < U i , VSI = 0; When U i ≤ U < 0.5U c , VSI = (U - U i ) / (0.5U c - U i ); When 0.5U c ≤ U ≤ U c ,

[0063] VSI = 1; When U c < U ≤ U b , VSI = (U - U b ) / (U c - U b ); When U > U b , VSI = 0.

[0064] S16: According to the collected induced flow velocity U i , critical swimming speed U c and burst swimming speed U b of adult fish and juvenile fish, the flow velocity suitability curve of adult fish and juvenile fish is respectively formulated. The flow velocity zoning results and flow velocity suitability index of adult fish and juvenile fish of four common carp are shown in Table 2, and the flow velocity suitability curve is shown in Figure 4 .

[0065] Table 2 Flow velocity zoning and flow velocity suitability index of adult fish uplink and juvenile fish downlink

[0066]

[0067] Step S2: Numerical simulation of the flow field of the gate control project under different flow conditions, including the following steps;

[0068] S21: A two-dimensional mathematical model of the upper and lower long river sections of the gate control hub is established, and the simulation range includes the upper river section 2km, the discharge gate and the lower river section 3km, as shown in Figure 5 .

[0069] S22: The two-dimensional mathematical model is verified by using the flow velocity data obtained by the existing gate section physical model.

[0070] S23: According to the regulation and operation scheme of the gate control hub, representative flow is selected to determine the calculation working condition. The selected typical working condition is: the discharge flow of the gate is 910m 3 / s, the upstream water level is 17.5m, the gate water level is 15.17m, and the gate opening mode is: the opening degree of No. 1-6 gate is 1.7m; the opening degree of No. 7 and No. 16 gate is 2.0m.

[0071] S24: Calculate the upstream and downstream flow field of typical working conditions, and obtain the hydraulic characteristics such as flow velocity, flow direction and water depth.

[0072] Step S3: Migration channel prediction of adult fish up-migration and juvenile fish down-migration, comprising the following steps:

[0073] S31: According to the flow velocity zoning and flow velocity suitability curve of adult fish and juvenile fish prepared in step S1, the upstream and downstream flow fields of each representative working condition obtained in step S2 are evaluated in terms of flow velocity suitability, so as to obtain the flow velocity suitability index of the migration channel suitable for adult fish up-migration and juvenile fish down-migration under each representative working condition. The flow velocity zoning is shown in FIG. 4. Figure 6

[0074] S32: Select the flow velocity suitability index of 0.4-1.0 as the suitable migration channel for fish, and predict the migration channel of adult fish up-migration and juvenile fish down-migration according to the same. The predicted up-migration and down-migration channels are shown in FIG. 5. The typical working condition is to open the gate locally, so the adult fish up-migration migration channel is that the adult fish migrates from the downstream natural river to the fishway inlet and passes through the fishway to up-migrate, and the juvenile fish down-migration migration channel is that the juvenile fish migrates from the upstream natural river to the opened gate and passes through the gate top overflow to down-migrate with the water flow. Figure 7

[0075] Step S4: According to the migration channel predicted in step S3 of adult fish up-migration and juvenile fish down-migration, if the migration channel is discontinuous, compare the size relationship between the flow velocity in the discontinuous area and the swimming ability of fish, and change the gate opening mode under the condition that the discharge is unchanged, comprising the following steps:

[0076] S41: According to the migration channel prediction result obtained in step S3, it can be seen that the up-migration migration channel and the down-migration migration channel are both discontinuous, wherein the up-migration migration channel has a discontinuous area of about 20m in length in the 80m area downstream of the fishway, and the down-migration migration channel is discontinuous at the opened gates 1-7 and 16. It is necessary to change the gate opening mode under the condition that the discharge is unchanged.

[0077] The connectivity judgment standard of the up-migration migration channel in step S41 is: from the downstream river to the fishway inlet or the fully opened gate, if there is a continuous uninterrupted migration channel with a width of more than twice the fish body, it indicates that the adult fish up-migration migration channel is continuous, otherwise it is discontinuous; the connectivity judgment standard of the down-migration migration channel is: from the upstream river to the opened gate, if there is a continuous uninterrupted migration channel with a width of more than twice the fish body, it indicates that the juvenile fish down-migration migration channel is continuous, otherwise it is discontinuous.

[0078] S42: According to the flow velocity zoning result obtained in S3, it can be seen that the up-migration migration channel discontinuous area, i.e. the 80m area downstream of the fishway, the flow velocity exceeds the burst swimming speed, and the discharge of gates 1-6 needs to be reduced.

[0079] ​​S43: analysis of the flow rate partition results obtained in S3 can see that the downstream migration channel is discontinuous, that is, the opening of the 1-7 and 16 gate, the flow rate exceeds the burst swimming speed, and the discharge of the single gate needs to be reduced.

[0080] After optimization, the optimized gate operation mode is finally determined as follows: the discharge is 910m 3 / s, the upstream water level is 17.5m, the downstream water level is 15.17m, the opening of the 1-2 gate is 1.7m, the opening of the 6-8 gate is 1.9m, and the opening of the 13-15 gate is 0.7m.

[0081] S44: after adjusting the gate opening, the connectivity of the upstream and downstream migration channels of the working condition is re-evaluated according to steps S2 and S3, and the flow rate partition results are as shown in Figure 8 , and the predicted migration channel results are as shown in Figure 9 It can be seen that the upstream migration channel of adult fish and the downstream migration channel of juvenile fish are continuous, and the narrowest width of the channel is more than 10m, wherein the adult fish can enter the fishway inlet from the left side of the downstream river channel, and the juvenile fish can enter the downstream through the overflow of the opened 6-8 gate from the right side of the upstream river channel.

[0082] The above step S44 determines that on the basis of the gate control hub regulation scheme for ensuring the connectivity of the two-way fish passage channel, auxiliary fish passage devices such as fish blocking nets and fish blocking electric fences can be arranged at the gate control hub to improve the fish passage efficiency, which can avoid the aggregation of adult fish in the downstream of the gate that is not fully opened, and guide the juvenile fish to pass through the appropriate gate.

[0083] The present application proposes a gate control hub regulation method suitable for the swimming ability of adult fish and juvenile fish and based on the prediction of the upstream migration channel of adult fish and the downstream migration channel of juvenile fish, which fully utilizes the characteristics of the gate control hub to solve the demand of two-way migration of fish.

[0084] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any changes or replacements within the technical scope disclosed by the present application can be easily thought by any person skilled in the art, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for regulating a gate-controlled hub to adapt to the upstream and downstream migration of multiple target fish species, characterized in that: The method is used for regulating water level of river channel in dry season, and adopts operation mode of regulating dry season and not regulating flood season, and the gate control hub comprises a discharge gate and a fishway, the discharge gate adopts a pneumatic shield gate, gate opening degree is adjusted between 0 and 1, the inlet of the fishway is located on the downstream bank of the gate, and the gate flow near the bank provides fish flow conditions for the inlet of the fishway, and the method comprises the following steps: Step S1: determining the flow velocity suitability curve suitable for multi-target adult fish and juvenile fish; Step S2: performing numerical simulation of flow field of the gate control project under different flow conditions to obtain the upstream and downstream flow fields of each representative working condition; Step S3: according to the flow velocity suitability curve of the adult fish and juvenile fish determined in step S1, evaluating the flow velocity suitability of the upstream and downstream flow fields of each representative working condition obtained in step S2, and predicting the migration channel of the adult fish and juvenile fish according to the evaluation result of the flow velocity suitability; Step S4: according to the migration channel of the adult fish and juvenile fish predicted in step S3, if the migration channel is discontinuous, comparing the size relationship between the flow velocity of the discontinuous area and the swimming ability of the fish, and changing the gate opening mode under the condition that the discharge flow is unchanged; The step S1 comprises: S11: obtaining the body length of the multi-target adult fish and juvenile fish in the fish passage object of the gate control hub project; S12: obtaining the swimming ability data of the adult fish and juvenile fish corresponding to the body length, including the induced flow velocity, the critical swimming speed and the burst swimming speed; S13: define the region where the flow rate is less than the induced flow rate as the non-inductive zone, i.e. U U i ; define the region where the flow rate is in the range between the induced flow rate and 0.5 times the critical swimming speed as the induced zone, i.e. U i U <0.5 U c ; define the region where the flow rate is in the range between 0.5 times the critical swimming speed and the critical swimming speed as the preferred zone, i.e. 0.5 U c U U c ; define the region where the flow rate is in the range between the critical swimming speed and the burst swimming speed as the burst zone, i.e. U c U U b ; define the region where the flow rate is greater than the burst swimming speed as the barrier zone, i.e. U > U b ;​​​​​​ S14: defining a dimensionless flow velocity suitability index VSI The flow velocity suitability index represents the degree of suitability of the flow velocity for fish migration, with a flow velocity suitability index of 0 indicating that the flow velocity in the area is not suitable for fish migration, and a flow velocity suitability index of 1 indicating that the flow velocity in the area is most suitable for fish migration, with the flow velocity suitability index being 0 for the no perception zone and the barrier zone, and the flow velocity suitability index being 1 for the preferred zone; S15: When U < U i , VSI =0; when U i ≤ U <0.5 U c , VSI =( U - U i ) / (0.5 U c - U i When 0.5 U c ≤ U ≤ U c , VSI =1; when U c < U ≤ U b , VSI =( U - U b ) / ( U c - U b );when U > U b , VSI =0; S16: according to the induced flow velocity, the critical swimming speed and the burst swimming speed of the adult fish and juvenile fish obtained in step S12, and the segmented flow velocity suitability index defined in step S15, the flow velocity suitability curve of the adult fish and juvenile fish is respectively formulated; the minimum value of the burst swimming speed for a variety of fish species U i the minimum value of the critical swimming speed for a variety of fish species U c the minimum value of the burst swimming speed for a variety of fish species U b the maximum value of the burst swimming speed for a variety of fish species The step S3 comprises: S31: according to the flow velocity suitability curve of the adult fish and juvenile fish determined in step S1, evaluating the flow velocity suitability of the upstream and downstream flow fields of each representative working condition obtained in step S2, thereby obtaining the flow velocity suitability distribution of the adult fish and juvenile fish under each representative working condition; S32: selecting the flow velocity suitability index 0.4-1.0 as the suitable migration channel of the fish, and predicting the migration channel of the adult fish and juvenile fish according to the suitable migration channel of the fish, wherein the adult fish up-migration channel includes two kinds: one is that the adult fish migrates from the downstream natural river channel to the fishway inlet and up-migrates through the fishway, and the other is that the adult fish migrates from the downstream natural river channel to the opened gate and up-migrates through the fully opened gate; the juvenile fish down-migration channel of the gate control hub refers to that the juvenile fish migrates from the upstream natural river channel to the opened gate and down-migrates through the gate top overflow with water flow; The step S4 comprises: S41: identifying the connectivity of the adult fish and juvenile fish up-migration and down-migration channel of each representative working condition, when the migration channel is discontinuous, the gate opening mode needs to be changed under the condition that the discharge flow is unchanged, specifically: S42: when the up-migration channel is discontinuous, if the flow velocity of the discontinuous area is close to the burst swimming speed of the adult fish, the opening degree of the gate at the corresponding position on the flow line in the area is reduced, and if the flow velocity of the discontinuous area is close to the induced flow velocity of the adult fish, the opening degree of the gate at the corresponding position on the flow line in the area is increased. S43: When the downstream migration channel is discontinuous, if the flow velocity of the discontinuous region is close to the juvenile fish explosion swimming speed, the opening of the gate at the corresponding position on the flow line in the region is reduced, and if the flow velocity of the discontinuous region is close to the juvenile fish sensitive flow velocity, the opening of the gate at the corresponding position on the flow line in the region is increased; S44: After adjusting the gate opening, the connectivity of the upstream and downstream migration channels for the working condition is re-predicted according to steps S2 and S3 until the upstream and downstream migration channels are both continuous; The connectivity judgment standard of the upstream migration channel in step S41 is: from the downstream natural river to the fishway inlet or the fully opened gate, if there is a continuous uninterrupted migration channel with a width of more than twice the fish body, it indicates that the upstream migration channel for adult fish is continuous, otherwise it is discontinuous; The connectivity judgment standard of the downstream migration channel is: from the upstream natural river to the opened gate, if there is a continuous uninterrupted migration channel with a width of more than twice the fish body, it indicates that the downstream migration channel for juvenile fish is continuous, otherwise it is discontinuous.

2. The method according to claim 1, wherein the method is characterized in that: In step S11, the body length of fish is obtained by collecting the fish resource survey results of the river section in the literature, and the principle of selecting the representative length of adult fish and juvenile fish is to select the smaller value in the range of body length, and multiple fish objects are selected respectively.

3. The method according to claim 1, wherein the method is characterized in that: The step S2 comprises: S21: A two-dimensional or three-dimensional mathematical model of the upstream and downstream long river sections of the gate control hub is established to simulate the flow field of the gate control project, and the simulation range includes the upstream river section, the sluice and the downstream river section; S22: The mathematical model described in step S21 is verified; S23: According to the regulation and control operation scheme of the gate control hub, a representative flow is selected to define the calculation condition; S24: Calculate the upstream and downstream flow fields of each condition to obtain the hydraulic characteristics, including flow velocity, flow direction and water depth.

4. The method according to claim 3, wherein the method is characterized in that: The mathematical model described in step S21 can simulate the discharge under different gate opening conditions.

5. The method according to claim 3, wherein the method is characterized by: Step S22 verifies the reliability of the mathematical model by obtaining the hydraulic parameters of the physical model test of the same gate control hub.

Images