EP4791953A1 - Fish migration system - Google Patents

Abstract

The present invention provides a fish migration device (10) designed for use in watercourses where obstacles such as power stations, dams, or similar structures hinder the free movement of fish The device (10) comprises pipes (14), an inlet valve (12), an outlet valve (13), a plurality of back flow chambers (11), one or more rest chambers (20), and multiple back flow and eddy areas (21). The device (10) forms a closed system that allows water to flow from an upper part to a lower part, effectively reducing both the speed and volume of water to levels that facilitate comfortable fish passage, thereby enables fish migration either upstream or downstream. Whereas the one or more rest chambers (20) and the back flow and eddy areas (21) allow fish to rest and then continue moving up or down in the device (10).

Description

FISH MIGRATION SYSTEM

Field of the invention

[0001] The present invention relates to a fish migration system for use in watercourses. More specifically, the invention is a fish migration device designed to facilitate the passage of fish through watercourses where obstacles such as power stations, dams, or similar structures hinder the free movement of fish.

Background and state of the art

[0002] Human activities have profoundly altered water sources around the world, often to the detriment of aquatic ecosystems. As societies develop and industrialize, numerous projects and installations ranging from dams and power stations to urban development and agriculture have been introduced into rivers, lakes, and other water bodies. While these projects bring significant benefits, they also pose substantial challenges for aquatic life, particularly for fish populations.

[0003] One major issue is the disruption of natural fish migration patterns. Many fish species depend on the ability to move freely between different sections of a watercourse to spawn, find food, or avoid predators. However, the construction of dams and other barriers can obstruct these essential migratory routes. This disruption not only impacts individual fish but can also lead to population declines, as fish may struggle to reach their spawning grounds or other critical habitats.

[0004] Efforts to mitigate these impacts are essential. Fish migration devices, such as fish ladders or bypass channels, have been developed to assist fish in navigating around obstacles and maintaining their natural migratory behaviours. However, traditional fish ladders often involve extensive groundwork and can be costly to install. Many existing fish ladders are either poorly maintained or inadequately designed, failing to effectively support fish migration. Additionally, conventional fish ladders require substantial water flow to function properly, which can be problematic for optimizing water usage in energy generation systems.

[0005] Recent innovations include the use of back flow chambers in fishways to address these challenges. Back flow chambers can reduce water speed, making it easier for fish to swim against the current. For example, Chinese Patent No. CN114481978B describes a fishway structure incorporating a Tesla valve to dissipate energy and reduce water speed. This fishway includes an upstream water inlet, a middle combined fishway with a Tesla flow channel, and a downstream water outlet. The Tesla valve configuration helps in managing water flow and reducing energy while facilitating fish migration.

[0006] Similarly, Chinese Patent Application CN116695650A describes a Tesla valvetype fishway featuring an energy dissipation channel separate from the fish passage channel. This design aims to assist fish migration around obstacles while managing water energy to reduce speed and turbulence.

[0007] Despite these advancements, existing fishways may still require significant installation efforts and maintenance. The present invention introduces a novel fish migration device that aims to facilitate fish passage with minimal disruption to natural environments. It is designed to be installed in both undeveloped watercourses and existing watercourses with suboptimal or poorly maintained fish ladders, thereby providing an efficient and less intrusive solution for promoting fish migration.

Summary of the invention

[0008] Aspects of the present invention provide a fish migration device designed for use in watercourses where obstacles such as power stations, dams, or similar structures hinder the free movement of fish.

[0009] In one aspect of the present invention, the fish migration device comprises pipes, an inlet valve, an outlet valve, a plurality of back flow chambers, and one or more rest chambers, to reduce speed and volume of water, facilitating migration of fish up or down.

[0010] In one aspect of the present invention, the fish migration device comprises pipes, an inlet valve, a plurality of back flow chambers, to reduce speed and volume of water, facilitating migration of fish up or down.

[0011] In one aspect of the present invention, the device forms a closed system that allows only water to flow from an upper part to a lower part, effectively reducing both the speed and volume of the water to levels that facilitate comfortable fish passage, thereby enabling fish migration both upstream and downstream.

[0012] In one aspect of the present invention, the device can be installed in a variety of settings, including underwater, above water, below ground, above ground, spanning across air, and mounted against walls or ceiling and can be incorporated into the dam during construction phase.

[0013] In one aspect of the present invention, the device is modular, allowing for flexible configuration and easy adjustments, which makes it adaptable for use in different elevations, slope ratio, watercourses and conditions.

[0014] In one aspect of the present invention, the device includes an inlet valve and an outlet valve that enable the shutdown of the device when needed.

[0015] Further details and specification of the invention are described in the detailed description and accompanying figures, providing comprehensive insights into the operation and functionalities of the present invention.

Brief description of the drawing

[0016] The foregoing aspects and many of the advantages of the present invention will be more appreciated and better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:

[0017] Fig.1 is a fish migration device in accordance with an embodiment of the present invention; and

[0018] Fig.2 is a fish migration device in accordance with another embodiment of the present invention. Detailed description of the invention

[0019] The present invention will now be described more fully hereinafter with reference to the accompanying drawings in which a preferred embodiment of the invention is shown. This invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, the embodiments are provided so that this disclosure will be thorough, and will fully convey the scope of the invention to those skilled in the art.

[0020] According to embodiments of the present invention, Fig. 1 illustrates a fish migration device 10 designed for use in watercourses where obstacles, such as power stations, dams, or similar structures, obstruct the free movement of fish. The fish migration device 10 features a passive resistance and flow control system designed to regulate water speed and flow, without the need for active mechanical components. The device 10 effectively moderates water flow and reduces speed, facilitating easier passage for fish. This passive approach minimizes maintenance requirements and operational complexity, while still achieving optimal conditions for fish migration.

[0021] The fish migration device 10 facilitates fish overcoming obstacles such as power stations, dams, or similar structures. The fish migration device 10 is a closed system designed to pass only water from an upper part to a lower part, reducing the water speed and quantity to a level that allows fish to swim through fish migration device 10 comfortably. The device 10 incorporates a plurality of back flow chambers 11, which slow down both the speed and volume of the water. These back flow chambers 11 are based on Tesla valve technology.

[0022] Speed reduction leads to a decrease in overall water flow, which enables to harness greener energy. This is because slower water flow can be more efficiently managed for sustainable energy production, often resulting in higher energy quality and value.

[0023] According to the configuration of the device 10, the closed system manages and limits the amount of water used for fish migration, allowing for the conservation of water that can be redirected for other purposes, such as power production. Additionally, the device 10 features an inlet valve 12 at an upper part and an outlet valve 13 at a lower part of the device 10, enabling the shutdown of the device 10 when needed.

[0024] Water is directed into a closed system located below the surface at a higher level of the river or water source. As the water flows into the device 10, it passes through the back flow chambers 11, which are designed to reduce both the speed and volume of the water.

[0025] The back flow chamber 11 operates by directing water into a pipe 14 with a junction 15. At the junction 15, the water follows the path of least resistance, with some flowing into a side branch 16. The main branch 17 of the pipe 14 includes a bend 18 that redirects the flow to a new intersection 19. At the intersection 19, the water from the side branch 16 collides with the water from the main branch 17, creating back flow, eddy and turbulence that slows down the overall flow speed.

[0026] In one embodiment, the correct number of the back flow chambers 11 are determined based on the height and dimensions of the pipe 14, the device 10 will reduce the water speed to a level at which fish can swim upstream. Additionally, fish will be able to swim in both directions within the device 10.

[0027] The device 10 reduces the speed of the water using a passive resistance and flow system. This approach leverages inherent resistance and flow dynamics within the device 10 to naturally slow down the water, without the need for active mechanical components. This method ensures that water flow is managed effectively, supporting fish migration while promoting energy efficiency and minimizing environmental impact.

[0028] In one embodiment, the device 10 further incorporates one or more resting chambers 20, allowing fish to rest while moving up or down the device 10.

[0029] In one embodiment, the device 10 further incorporates multiple backflow and eddy areas 21 , providing spaces for fish to rest before continuing their migration up or down the device 10. These backflow and eddy areas 21 function similarly to rocks and stones in a river.

[0030] The inlet valve 12 is installed at the upper part, and the outlet valve 13 is installed at the lower part 12 of the device 10. Both the inlet valve 12 and outlet valve 13 can be closed to shut down the facility during the winter season, or when needed, such as during floods or periods of low water flow. In a preferred embodiment, both the inlet valve 12 and outlet valve 13 are opened during the migration season to facilitate fish passage.

[0031] Additionally, the upper part and lower part of the device 10 can be ballasted to remain submerged during periods of use. When the device 10 is not in use, it can be lifted out of the water, or the inlet valve 12 and outlet valve 13 can be closed to shut off the device 10. This is particularly useful for preventing frost blasts during cold conditions.

[0032] The device 10 is designed to withstand both internal and external influences. The device 10 can be further equipped with natural or artificial lighting to guide fish through the device 10. Additionally, in another embodiment fish traps can be installed to prevent unwanted fish species from entering into the device 10. A notable feature of this solution is its ability to adjust the water speed by adding or removing the back flow chambers 11. The flexibility of the device 10 supports fish species that may struggle with traditional fish ladders.

[0033] Further, the design and functionality of the device 10 are optimized through precise calculations and tests. The following parameters such as pitch, design, degrees, angles, materials, internal surface and number of the back flow chambers 11 are calculated based on conditions at the installation site. These calculations and tests are used as a basis to optimize the speed and flow of water within the device 10, manage water quantity, and ensure the calculated size of fish can move through the device 10 effectively.

[0034] According to another embodiment of the present invention as shown in Fig. 2, the fish migration device 10 incorporates multiple backflow chambers 11 and box shapes 22 are designed to serve as the area from which computational fluid dynamics (CFD) are measured. As shown in Fig. 2, the inlet valve 12 is located below the surface, preventing air from entering the device 10 and allowing only water to flow from the upper part to the lower part. This effectively reduces the speed and volume of the water to levels that facilitate comfortable fish passage, enabling migration both upstream and downstream. Basically, the box shappe 22 represents dam or lake. [0035] According the present invention, a comparison demonstrates the reduction of water speed and volume using a straight tube measuring 14 meters long, 50 centimeters in diameter, and featuring a 3.5-meter drop, both without and with the fish migration device 10.

[0036] Without the device 10: Volume is 3100 l/s and Water speed is16 m/s (58 km/h).

[0037] With the device 10 employs passive resistance and flow control with six back flow chambers 11: Volume is 309 l/s and Water speed is 1.7 m/s (6 km/h)

[0038] This result shows a reduction in water speed when using straight pipe versus installing backflow chambers 11 for a specific height and length. According to the invention, this allows for adjustments by adding or removing backflow chambers 11 based on the type of fish and their swimming speed.

[0039] One advantage of the present invention is that the device 10 is modular. This modular design allows for flexible configuration and easy adjustments, making it adaptable for use in different watercourses and conditions.

[0040] One advantage of the present invention is that the length and dimensions of the that the device 10 are flexible and adaptable to various geographic conditions. This means it can be adjusted to avoid limitations during production, installation, and use.

[0041] Another advantage of the present invention is that the device 10 is modular, enabling simple and quick assembly. The device 10 can be produced in various materials and dimensions, offering flexibility to meet different needs and environmental conditions.

[0042] Another advantage of the present invention is that the device 10 can be installed in a variety of settings, including underwater, above water, below ground, above ground, spanning across air, and mounted against walls and ceilings. This versatility makes it adaptable to diverse installation environments.

[0043] Another advantage of the present invention is that the device 10 can be made in various shapes, including round, square, or combinations thereof, and can also be made from transparent materials. This transparency can provide visibility into the device 10 operation, enhancing monitoring and inspection capabilities. Additionally, lights can be installed within the device 10, enhancing visibility and guiding fish through the facility.

[0044] Further, the device 10 can be emptied of water during winter to prevent ice formation, ensuring continued functionality and avoiding potential damage from freezing conditions.

[0045] Another advantage of the present invention is that the device 10 can be opened and closed as needed, providing flexibility for maintenance, seasonal adjustments, and other operational requirements.

[0046] Another advantage of the present invention is that the device 10 can be mounted according to the siphon principle, which facilitates efficient water transfer and helps maintain the desired flow dynamics.

[0047] An advantage of the present invention is that the device 10 can be installed with the intake and outlet positioned below the water level, ensuring effective operation and consistent water flow through the device 10.

[0048] Another advantage of the present invention is that the device 10 can be installed in a wide range of locations, including both old and new fish ladders, dams, turbines, rivers, small rivers, streams with high or steep gradients, fish tanks, and industrial applications. This versatility makes it suitable for various environments and uses, enhancing its adaptability and effectiveness in supporting fish migration and water management.

[0049] Another advantage of the present invention is that it helps restore fish fauna across the entire watercourse by facilitating migration in level-regulated water flow systems, thereby reinstating collective fish habitats. The device 10 requires less environmental intervention and has a lower environmental impact, footprint, and construction time compared to traditional fish migration solutions. This makes it a more sustainable and efficient option for supporting aquatic ecosystems.

[0050] Another advantage of the present invention is that its speed reduction mechanism results in decreased water flow, which allows the regulator to harness greener energy. This greener energy often commands a higher price per kilowatt (kW), providing economic benefits. The device 10 also satisfies environmental requirements for organized fish migration, aligning with the power supplier’s green energy goals.

[0051] Furthermore, the device 10 requires less environmental intervention, has a lower environmental impact and footprint, and involves reduced construction time compared to traditional fish migration solutions.

[0052] Another advantage of the present invention is that the device 10 is calibrated to ensure that it supports the fish's ability to swim both upstream and downstream. By carefully adjusting the water flow and speed reduction mechanisms, the system maintains optimal conditions for fish migration, allowing them to navigate the device effectively in both directions.

[0053] The foregoing description of embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention without departing from the scope of the invention. The embodiments were chosen and described in order to explain the principles of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated.

Claims

Claims What is claimed is:

1 . A fish migration device (10) allowing only water to enter for use in watercourses comprising pipes (14), an inlet valve (12) at an upper part, an outlet valve (13) at a lower part, a plurality of back flow chambers (11), one or more rest chambers (20), and multiple back flow and eddy areas (21) to reduce speed and volume of water, facilitating migration of fish up or down.

2. The device (10) according to claim 1 , wherein the device (10) can be installed in a variety of settings, including underwater, above water, below ground, above ground, spanning across air, and mounted against walls or ceilings.

3. The device (10) according to claim 1 , wherein the device (10) is modular, allowing for flexible configuration and easy adjustments, making adaptable for use in different watercourses and conditions.

4. The device (10) according to claim 1 , wherein the inlet valve (12) and the outlet valve (13) enable shutdown of the device (10) when needed.

5. The device (10) according to claim 1 , wherein device (10) is designed for use in watercourses where obstacles, such as power stations, dams, or similar structures, obstruct the free movement of fish.

6. A fish migration device (10) comprising: pipes (14); a plurality of back flow chambers (11) to regulate water speed and flow; an inlet valve (12); an outlet valve (13); one or more rest chambers (20); and multiple back flow and eddy areas (21), wherein the device (10) is configured to reduce the speed and volume of water, thereby facilitating the migration of fish either up or down through the device (10), wherein the one or more rest chambers (20) and the back flow and eddy areas (21) integrated to allow fish to rest and recover during migration before continuing moving up or down in the device (10).

7. The device (10) according to claim 6, wherein the device (10) can be installed in a variety of settings, including underwater, above water, below ground, above ground, spanning across air, and mounted against walls or ceiling and can be incorporated into a dam during construction stage.

8. The device (10) according to claim 7, wherein the device (10) is modular, allowing for flexible configuration and easy adjustments, making adaptable for use in different watercourses and conditions.

9. The device (10) according to claim 6, wherein the inlet valve (12) and the outlet valve (13) enable shutdown of the device (10) when needed.

10. The device (10) according to claim 6, wherein device (10) is designed for use in watercourses where obstacles, such as power stations, dams, or similar structures, obstruct the free movement of fish.