Intelligent riverway retaining dam system based on ecological function regulation and control

Abstract

The invention discloses an intelligent riverway retaining dam system based on ecological function regulation and control in the technical field of water conservancy ecology. The intelligent riverway retaining dam system comprises a retaining dam body and a server. The side, close to the shoreside, of the retaining dam body is provided with multiple stages of water pools distributed in a stepped mode, every two adjacent stages of water pools are communicated through an inclined water channel, and the server comprises an acquisition module, a data processing module and an execution module; the acquisition module is used for acquiring feature images of migrated fishes and water flow velocity in a water channel; the data processing module is used for analyzing the fish feature image through a trained deep learning algorithm, so that the water flow speed is matched with the water flow speed of corresponding fish migration; and the execution module is used for opening, closing and adjusting a gate of the fishway according to the instruction of the data processing module. According to the scheme, the problems that the flow speed of water flow of an existing fishway is unstable, and fish migration is affected are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water conservancy ecology, and particularly to an intelligent riverway dam system based on ecological function regulation. BACKGROUND

[0002] A dam is a man-made structure primarily used to intercept rivers or other water sources to control water flow, store water resources, generate electricity, irrigate, prevent floods, and provide drinking water. Dams are an important part of water conservancy projects and are widely used in agriculture, industry, and urban water supply systems, and have a significant impact on the ecological environment.

[0003] Fish migration refers to the periodic long-distance migration behavior of certain fish along a specific route for reproduction, foraging, or seeking suitable habitats. This behavior is an important part of the life cycle of many fish and plays a crucial role in maintaining population size and distribution. However, when a dam crosses a river, it not only changes the natural hydrological conditions but also forms a physical barrier, severely affecting the normal migration path of fish. When migration is blocked, the fish populations upstream and downstream cannot exchange genes normally, leading to a decrease in genetic diversity and increasing the risk of inbreeding, which weakens the ability of the population to adapt to environmental changes. At the same time, fish in a certain area cannot obtain enough breeding opportunities or find suitable food sources, which may lead to a sharp decline in the number of fish populations in that area or even local extinction.

[0004] Therefore, in order to avoid the blockage of fish migration and ensure ecological normality, a dam migration channel is disclosed in patent No. 202111610752.6, which includes a dam-passing pipe, an ascending pipe, a connecting pipe, and a dam bottom water inlet pipe. An automatic air valve is provided on the dam-passing pipe to automatically adjust the air volume, and the ascending pipe is provided with an air pipe. The air volume entering the pipeline is adjusted according to the water flow speed and size through the automatic air valve and air pipe, so that the water flow and speed in the pipeline are maintained at an appropriate size. A small fish channel is provided in the ascending pipe, and the water flow is slowed down by the interval setting of the baffle to facilitate the migration of small fish with poor physical strength. For large dams with high water level difference, a relay groove can be set in the dam to complete the automatic migration channel through water pump water storage. This migration channel can automatically adjust the water flow size and slow down the water flow speed to form a closed migration channel, with very good migration effect, and it is worth promoting and using. The patent sets an automatic air valve on the dam-passing pipe to adjust the air valve according to the water flow speed and size, so as to maintain the appropriate pressure in the pipeline to adjust the water flow and speed. However, different fish species have different requirements for water flow speed during migration. Some fish species require slower water flow speed during migration, while some fish species require faster water flow speed. In this patent, it cannot identify which fish species are migrating, so it cannot automatically adjust the flow rate to suit the migration of the fish species. SUMMARY

[0005] The present application aims to provide an intelligent riverway dam system based on ecological function regulation to solve the problem that current fishways cannot automatically match the migration water flow speed according to different fish.

[0006] To solve the above technical problems, the present application provides the following technical solutions: an intelligent riverway dam system based on ecological function regulation, comprising a dam body and a server.

[0007] The dam body is arranged in a riverway and is used to raise the water level to form a reservoir area.

[0008] The dam body is provided with a plurality of stepped water pools on the side close to the bank, and adjacent two water pools are connected through an inclined waterway, which serves as a channel for fish to swim from a lower water pool to an upper water pool.

[0009] The server comprises a collection module, a data processing module and an execution module.

[0010] The collection module is used to collect the characteristic images of migrating fish and the water flow speed in each waterway, and the fish characteristic images include the shape, contour, texture and fin of the fish.

[0011] The data processing module is used to receive the data collected by the collection module, analyze the fish characteristic images through a trained deep learning algorithm, determine the fish in the images, and determine the water flow speed range in the fishway according to the fish.

[0012] The execution module is used to open the gate of the fishway according to the water flow speed determined by the data processing module, control the water flow rate in the fishway through the opening degree of the gate, and control the water flow speed in the fishway.

[0013] The working principle of the present application is as follows: the present application is used for intercepting river flow by the dam body, raising the water level to form a reservoir area, controlling the discharge flow through the through hole to adjust the overall water level and flow rate of the river, and a plurality of water pools arranged in a stepped manner are arranged on one side of the dam body close to the bank, and the adjacent two water pools are connected through an inclined water channel, and the water in the reservoir area flows into the lowermost water pool through the water channel. When fish migrate through the water channel, the collection module collects the images of the migratory fish, the collected images are sent to the data processing module, the data processing module processes the collected images, identifies the fish species through the trained deep learning algorithm, and then the data processing module retrieves the pre-recorded suitable flow rate range of the fish migration according to the identified fish species, determines the target flow rate range of the current fishway that needs to be regulated, and the execution module drives the gate according to the target flow rate of the data processing module to initially open the corresponding gate opening for water release, and then the fish can swim through the dam body by the water channel and the water pool.

[0014] The present application has the following advantages:

[0015] 1. Compared with the prior art, the present application identifies the target fish through a deep learning algorithm, adjusts the flow rate in the fishway according to the exclusive migration flow rate of each fish, and ensures that the flow rate is stable within the identified fish migration flow rate threshold. In this way, not only is the flow rate too large and the fish needs to consume a lot of physical strength to resist the flow, but also the flow rate is too small and cannot effectively guide the identified fish migration.

[0016] 2. The closed loop link of the collection module, the data processing module and the execution module realizes data collection, identification and execution, and the whole adjustment process can be completed within one second, realizing fast response. Compared with the existing fishway which relies on manual adjustment, the adjustment efficiency is greatly improved.

[0017] Further, a PID control module is further included, which is used for comparing the flow rate fed back in the collection module with the flow rate determined in the data module, when the flow rate in the fishway is less than the minimum flow rate of the current fish migration, the PID control module calculates the increase in the gate opening size of the fishway through the difference between the flow rate in the fishway and the maximum flow rate of the current fish migration, and when the flow rate in the fishway is greater than the maximum flow rate of the current fish migration, the PID control module calculates the decrease in the gate opening size of the fishway through the difference between the flow rate in the fishway and the minimum flow rate of the current fish migration.

[0018] The execution module is further used for increasing or decreasing the opening of the gate according to the calculation output of the PID control module.

[0019] The purpose is that the acquisition module acquires the flow rate of all waterways in real time during the fish swim into the waterways and pools, the PID control module compares the acquired flow rate with the set flow rate, calculates the deviation value, and then calculates the opening adjustment amount of the gate according to the deviation value, if the actual flow rate is lower than the target minimum value, the gate opening that needs to be increased (the greater the difference, the more the opening is increased) is calculated, the flow rate is increased to improve the flow rate. If the actual flow rate is higher than the target maximum value: calculate the gate opening that needs to be reduced (the greater the difference, the more the opening is reduced), reduce the flow rate to reduce the flow rate.

[0020] Meanwhile, it also has the function of self-adaptive adjustment of water level difference, for example, when the water level of the reservoir area rises due to heavy rain, the flow rate of the waterway increases suddenly to exceed the upper limit of the optimal flow rate of the migratory fish, the system automatically reduces the gate opening, and the flow rate is suppressed within the range of the optimal flow rate. When the water level difference is reduced in the dry season, the flow rate is lower than the lower limit of the optimal flow rate of the migratory fish, the system increases the opening to increase the flow rate to the optimal flow rate range, forming an effective guiding water flow.

[0021] Further, the acquisition module includes a plurality of high-definition cameras and a plurality of flow rate sensors, the plurality of high-definition cameras are respectively installed in the fishway entrance and each pool; the plurality of flow rate sensors are respectively installed in different waterways.

[0022] The high-definition camera installed in the fishway entrance and each pool continuously shoots the fish feature image, and transmits the image to the processing module; and the flow rate sensor monitors the flow rate in real time and synchronously transmits to the PID control module.

[0023] Further, the deep learning algorithm selects a deep learning network based on YOLO to train the information of the fish feature image, and the specific steps include:

[0024] S01, acquire 8 kinds of target fish feature images, the number of each fish feature image is greater than 500, and label each image to obtain a data set;

[0025] S02, divide the data set into a training set, a test set and a verification set according to the ratio of 8:1:1;

[0026] S03, construct a training model based on YOLO, train the training set and the test set, adjust the parameters, and find the best weight file;

[0027] S04, test the verification set image according to the obtained weight file.

[0028] Further, the fish includes grass carp, crucian carp, silver carp, bighead carp, copper fish, schizothoracinae, hypophthalmichthys nobilis and mandarin fish, and the water flow speed of the fishway during the preset migration of the fish is: 0.4-1.0 m / s for grass carp and crucian carp; 0.3-0.8 m / s for silver carp, bighead carp and mandarin fish; 0.5-1.2 m / s for copper fish; 0.6-1.0 m / s for schizothoracinae; and 0.5-0.8 m / s for hypophthalmichthys nobilis.

[0029] Further, the dam body includes two slopes of the concrete dam body, one of which is located on the upstream side of the concrete dam body and is made of gabion, and the length ratio of the vertical section to the horizontal section of the slope is 1:1; the other slope is located on the downstream side of the concrete dam body and is made of the interlayer structure of gabion and concrete, and the length ratio of the vertical section to the horizontal section of the slope is 1:3.

[0030] The purpose is that the concrete dam body itself has high strength and rigidity as a core support structure; and the slope part plays a role in buffering and dispersing load, which improves the stability of the whole dam together, and the gabion has a certain flexibility, which can adapt to the slight deformation of the foundation without structural damage, thereby protecting the concrete dam body from stress concentration; and the gabion structure has good water permeability and plantability, and the soil can be accumulated in the filled stone gap to promote the growth of plant roots, which is beneficial to ecological restoration and beautifying the environment. The wider 1:3 slope structure is used on the downstream side to provide a larger surface area for vegetation coverage, further enhancing the water and soil conservation capacity.

[0031] Further, the gate includes vertical guide rails fixed on opposite sides of the fishway, a sliding block is sleeved on each vertical guide rail, and the same gate body is fixedly connected to the two sliding blocks and used for sliding up and down in the fishway to open and close the fishway; vertical threaded rods are fixedly connected to both ends of one side of the gate body; a pulley is rotatably connected to the top of the opposite side walls of the fishway, a threaded hole is arranged at the center of the pulley, and the pulley is threadedly connected with the threaded rods through the threaded hole; and the pulley is driven to rotate by a motor.

[0032] A fish mouth is arranged in the middle of the gate body and vertically extends downward to the bottom of the gate body, and the fish mouth is used for fish to pass through the gate body.

[0033] When the fishway needs low flow rate of water flow, the door body completely closes the fishway, only leaving the fish mouth to release water, and most of the water is blocked by the door body, so that the water release amount is reduced, and the purpose of slowing down the water flow rate is achieved, and at the same time, fish can pass through the door body through the fish mouth to ensure normal migration of fish; when the water flow rate needs to be increased, the execution module controls the two motors to start synchronously, and the motor drives the belt pulley to rotate when starting, and since the belt pulley is connected to the side wall of the fishway and is in threaded connection with the threaded rod, and the threaded rod is fixedly connected with the door body, the rotation of the belt pulley drives the threaded rod to move upward, and the upward movement of the threaded rod drives the door body to move upward, so that the gap between the bottom of the door body and the bottom of the fishway is increased, and as the gap increases, the water flow rate in the fishway is gradually increased, and the purpose of increasing the water flow rate is achieved, and at the same time, when the gap is greater than the body height of the fish, the fish can also swim through the gap to pass through the door body; similarly, when the water flow rate in the fishway is too large due to the large opening of the door body, the execution module controls the motor to operate in reverse, so that the door body moves downward to reduce the gap between the bottom of the door body and the bottom of the fishway, and the purpose of reducing the water flow rate is achieved, and when the gap between the door body and the fishway is insufficient for the fish to swim through, the fish swims through the fish mouth to pass through the door body. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 It is a structure schematic view of an embodiment of the intelligent riverway dam system based on ecological function regulation of the application;

[0035] Figure 2 It is a structure schematic view of the fishway in the embodiment; Figure 1

[0036] Figure 3 It is a structure schematic view of the front view of the valve in the embodiment;

[0037] Figure 4 It is a structure schematic view of the rear view of the valve in the embodiment;

[0038] Figure 5 It is a state diagram when the valve is opened in the embodiment. Figure 4

[0039] The reference signs in the drawings of the specification include: slope protection 1, concrete dam body 2, water pool 3, waterway 4, traction motor 5, traction wheel 6, traction rope 7, guide rail 8, fish mouth 9, fish door 10, sliding block 11, door body 12, belt pulley 13, threaded rod 14. DETAILED DESCRIPTION

[0040] The following will be further described in detail through specific embodiments:

[0041] The embodiment is basically as shown in the accompanying drawings: Figure 1 and the accompanying drawings: Figure 2

[0042] ​​​The intelligent riverway dam system based on ecological function regulation comprises a dam body and a server.

[0043] The dam body is arranged in a riverway, and comprises two concrete dam bodies 2 and two revetments 1.

[0044] The dam body is arranged in a riverway, and comprises two concrete dam bodies 2 and two revetments 1.

[0045] The server comprises a collection module, a data processing module, an execution module and a PID control module.

[0046] The collection module comprises a plurality of high-definition cameras and a plurality of flow rate sensors.

[0047] The high-definition cameras are used to collect characteristic images of fish for migration, and the characteristic images of fish include the shape, contour, texture and fins of fish.

[0048] The data processing module is used to analyze the characteristic images of fish by using a trained deep learning algorithm, to determine the fish in the images, including blue fish, grass carp, silver carp, bighead carp, crucian carp, schizothoracinae, catfish and mandarin fish.

[0049] The PID control module is configured to compare the flow rate of the water flow fed back by the acquisition module with the flow rate of the water flow determined by the data module, and when the flow rate of the water flow in the fishway is less than or close to the minimum flow rate of the current fish migration, the PID control module calculates the size of the gate opening of the fishway according to the difference between the flow rate of the water flow in the fishway and the maximum flow rate of the current fish migration, and the greater the difference, the greater the gate opening calculated by the PID control module; when the flow rate of the water flow in the fishway is greater than or close to the maximum flow rate of the current fish migration, the PID control module calculates the size of the gate opening of the fishway according to the difference between the flow rate of the water flow in the fishway and the minimum flow rate of the current fish migration, and the greater the difference, the greater the gate opening calculated.

[0050] The execution module is configured to open the gate of the fishway according to the flow rate of the water flow determined by the data processing module, control the flow rate of the water flow in the fishway by controlling the flow of the water flow into the fishway through the opening of the gate, and increase or decrease the opening of the gate according to the calculation output of the PID control module.

[0051] The deep learning algorithm selects a deep learning network based on YOLO to train the information of the fish feature image, and the specific steps include:

[0052] S01, collect 8 kinds of target fish feature images, each fish feature image is more than 500, and each image is labeled to obtain a data set;

[0053] S02, divide the data set into a training set, a test set and a validation set according to a ratio of 8:1:1;

[0054] S03, construct a training model based on YOLO to train the training set and the test set, adjust the parameters, and find the best weight file;

[0055] S04, test the validation set image according to the obtained weight file.

[0056] The gate includes vertical guide rails 8 fixed on opposite sides of the waterway 4, and a sliding block 11 is slidingly sleeved on each vertical guide rail 8. The same door body 12 is fixedly connected to the two sliding blocks 11. The door body 12 is used for sliding up and down in the waterway 4 to realize the opening and closing of the waterway 4. The two ends of one side of the door body 12 are fixedly connected with vertical threaded rods 14. The top of the opposite sides of the waterway 4 is rotatably connected with a pulley 13. The center of the pulley 13 is provided with a threaded hole. The pulley 13 is threadedly connected with the threaded rod 14 through the threaded hole. The pulley 13 is driven to rotate by the motor through the belt;

[0057] The middle part of the door body 12 is provided with a fish mouth 9 extending vertically downward to the bottom of the door body 12, the fish mouth 9 is used for fish to pass through the door body 12, a fish door 10 for closing the fish mouth 9 is vertically and slidably connected to the door body 12, the top of the fish door 10 is fixedly connected with a traction rope 7, the top of the door body 12 is fixedly connected with a traction motor 5, the output shaft of the traction motor 5 is fixedly connected with a traction wheel 6, and the traction rope 7 is wound on the traction wheel 6.

[0058] The specific implementation process is as follows:

[0059] The dam body intercepts the river flow, raises the water level to form a reservoir area, and the through hole controls the discharge flow to adjust the overall water level and flow rate of the river. A plurality of water pools 3 are arranged in a stepped manner on one side of the dam body close to the bank, and the adjacent two water pools 3 are connected through inclined water channels 4. The water in the reservoir area flows into the lowermost water pool 3 through the water channels 4. When fish migrate through the water channels 4, the high-definition camera collects the images of the migrating fish and transmits the collected images to the data processing module. The data processing module processes the collected images, identifies the species of the fish through the trained deep learning algorithm, and then determines the target flow rate range that needs to be regulated for the current fishway according to the identified species of the fish. At this time, the execution module drives the gate to open the corresponding gate opening degree for water release according to the target flow rate of the data processing module, and then the fish can swim over the dam body through the water channels 4 and the water pools 3.

[0060] In the process of fish swimming into the water channels 4 and the water pools 3, the flow rate sensor collects the flow rate of all water channels 4 in real time and transmits it to the PID control module. The PID control module compares the collected flow rate with the set flow rate, calculates the deviation value, and then calculates the gate opening adjustment amount according to the deviation value. If the actual flow rate is lower than the target minimum value, the gate opening needs to be increased (the larger the difference, the more the opening is increased), the flow rate is increased to increase the flow rate. If the actual flow rate is higher than the target maximum value, the gate opening needs to be reduced (the larger the difference, the more the opening is reduced), the flow rate is reduced to reduce the flow rate.

[0061] When the waterway 4 needs low flow rate of water flow, the door body 12 completely closes the waterway 4, only leaving the fish mouth 9 to discharge water, and most of the water is blocked by the door body 12, so as to reduce the water discharge amount, and then achieve the purpose of slowing down the water flow rate, and at the same time, the fish can pass through the door body 12 through the fish mouth 9, ensuring the normal migration of the fish; when the water flow rate needs to be increased, the execution module controls the two motors to start synchronously, and the motor drives the belt pulley 13 to rotate when starting, since the belt pulley 13 is rotationally connected to the side wall of the waterway 4 and is threadedly connected with the threaded rod 14, and the threaded rod 14 is fixedly connected with the door body 12, the rotation of the belt pulley 13 drives the threaded rod 14 to move upward, and the upward movement of the threaded rod 14 drives the door body 12 to move upward, and the upward movement of the door body 12 increases the gap between the bottom of the door body 12 and the bottom of the waterway 4, and with the increase of the gap, the water flow rate in the waterway 4 is gradually increased, and then the purpose of increasing the water flow rate is achieved, and at the same time, when the gap is greater than the body height of the fish, the fish can also swim through the gap to pass through the door body 12; similarly, when the water flow rate in the waterway 4 is too large due to the large opening of the door body 12, the execution module controls the motor to operate reversely, so as to drive the door body 12 to move downward and reduce the gap between the bottom of the door body 12 and the bottom of the waterway 4, and then the purpose of reducing the water flow rate is achieved, and when the gap between the door body 12 and the waterway 4 is insufficient for the fish to swim through, the fish swims through the door body 12 through the fish mouth 9.

[0062] When the waterway 4 needs to be completely closed, the execution module controls the traction motor 5 to start, and the traction motor 5 drives the traction wheel 6 to rotate when starting, and the traction wheel 6 rotates to pay out the traction rope 7, at this time, the fish door 10 is no longer pulled by the traction rope 7, and then slides downward on the door body 12 under the action of gravity until moves to the bottom of the waterway 4 to complete the closure of the waterway 4. Similarly, when the fish mouth 9 needs to be opened, the execution module starts the traction motor 5 to operate reversely, and then drives the traction wheel 6 to wind the traction rope 7 and pull the fish door 10 upward, so as to open the fish mouth 9.

Claims

1. An intelligent river dam system based on ecological function regulation, characterized by: Including the dam body and server; The water retaining dam body is arranged in the river channel and is used to raise the water level to form a reservoir area; The side of the dam body close to the bank is provided with a multi-level pool distributed in a stepped manner, and the adjacent two levels of pools are connected by an inclined waterway, which serves as a channel for fish to swim from the lower level pool to the upper level pool; The server includes a collection module, a data processing module, and an execution module; The acquisition module is used to collect characteristic images of migrating fish and the water flow velocity in each waterway, wherein the characteristic images of fish include the shape, outline, texture and fins of the fish; The data processing module is used to receive the data collected by the acquisition module, and analyze the fish feature image through the trained deep learning algorithm to determine the fish in the image. After the fish is determined, the water flow speed range in the fishway is determined according to the fish; The execution module is used to open the gate of the fishway according to the water flow speed determined in the data processing module, and control the water flow rate in the fishway by controlling the opening of the gate.

2. The intelligent river dam system based on ecological function regulation according to claim 1 is characterized by: The invention also includes a PID control module, wherein the PID control module is used to compare the water flow velocity fed back from the acquisition module with the water flow velocity determined in the data module. When the water flow velocity in the fishway is less than the minimum water flow velocity for the current fish migration, the PID control module calculates the increase of the gate opening of the fishway by using the difference between the water flow velocity in the fishway and the maximum water flow velocity for the current fish migration; when the water flow velocity in the fishway is greater than the maximum water flow velocity for the current fish migration, the PID control module calculates the decrease of the gate opening of the fishway by using the difference between the water flow velocity in the fishway and the minimum water flow velocity for the current fish migration; The execution module is further configured to increase or decrease the opening of the gate according to the calculation output of the PID control module.

3. The intelligent river dam system based on ecological function regulation according to claim 2 is characterized by: The acquisition module includes multiple high-definition cameras and multiple flow rate sensors. The multiple high-definition cameras are respectively installed at the fishway entrance and each pool; and the multiple flow rate sensors are respectively installed in different waterways.

4. The intelligent river dam system based on ecological function regulation according to claim 3 is characterized by: The deep learning algorithm uses a YOLO-based deep learning network to train information on fish feature images. The specific steps include: S01. Collect characteristic images of 8 target fish species, with the number of characteristic images of each fish species exceeding 500, and label each image to obtain a dataset; S02, divide the data set into training set, test set and validation set in a ratio of 8:1:1; S03. Build a YOLO-based training model, train it through the training set and test set, adjust the parameters, and find the best weight file; S04. Test the validation set images based on the obtained weight file.

5. The intelligent river dam system based on ecological function regulation according to claim 4 is characterized by: The fish include black carp, grass carp, silver carp, bighead carp, copper carp, schizothorax, bighead carp and mandarin fish. The water flow speed of the fishway during the preset migration of the fish is: black carp and grass carp 0.4-1.0m / s; silver carp, bighead carp and mandarin fish 0.3-0.8m / s; copper carp 0.5-1.2m / s; schizothorax 0.6-1.0m / s; bighead carp 0.5-0.8m / s.

6. The intelligent river dam system based on ecological function regulation according to claim 1 is characterized by: The water retaining dam body includes two slope protections of the concrete dam body, one of which is located on the upstream side of the concrete dam body and is made of gabion stone cages, and the length ratio of the vertical section to the horizontal section of the slope protection is 1:1; the other slope protection is located on the downstream side of the concrete dam body and is made of an interlayer structure of gabion stone cages and concrete, and the length ratio of the vertical section to the horizontal section of the slope protection is 1:

3.

7. The intelligent river dam system based on ecological function regulation according to any one of claims 1 to 5, characterized in that: The gate includes vertical guide rails fixed on opposite sides of the fishway, with sliders slidably sleeved on the vertical guide rails, and the same door body is fixedly connected to the two sliders. The door body is used to slide up and down in the fishway to open and close the fishway. Both ends of one side of the door body are fixedly connected to vertical threaded rods. The tops of the opposite side walls of the fishway are rotatably connected to pulleys, and a threaded hole is provided at the center of the pulley. The pulley is threadedly connected to the threaded rod through the threaded hole, and the pulley is driven to rotate by a motor; A fish opening is provided in the middle of the door body, which extends vertically downward to the bottom of the door body. The fish opening is used for fish to pass through the door body.

Images