Fish collecting device for evaluating descending efficiency of fishes in water replenishing channel based on natural state

Abstract

According to the technical scheme, the fish collecting device for evaluating the descending efficiency of the fishes in the water supplementing channel based on the natural state comprises a gate pier, a blocking net is arranged at an outlet of the gate pier, a plurality of grid bars are arranged on the upper half portions of the two sides of the blocking net, stretching nets are arranged on the lower half portions and the bottom face of the two sides of the blocking net, and a collecting cage is arranged at the outlet of the blocking net. The outlet of the collecting cage is movably connected with the intercepting net. The fish collecting cage has the beneficial effects that (1) the grid bars and the stretching net of the device prevent fishes from being hurt in the process of guiding the fishes to swim to the collecting cage, so that the abnormal death rate of the fishes is reduced; and (2) the inlet of the collection cage of the device is of a funnel-shaped structure, so that the collected fishes are prevented from getting lost due to overlarge water flow and returning from the original inlet, the collection success rate is improved, and the types and morphological indexes of the fishes in the downward direction are accurately counted.

Description

Technical Field

[0001] The utility model belongs to the technical fields of water conservancy projects and fish passage facilities, and particularly relates to a fish collecting device for evaluating the downstream efficiency of fish in a water replenishing channel under natural conditions. Background Technique

[0002] The construction of water conservancy projects and fish protection are closely related topics. Among them, the construction of water conservancy projects takes into account comprehensive benefits such as flood control, power generation, irrigation, water supply, aquaculture, and shipping. However, while taking into account these benefits, it directly affects the normal development of fish populations. Fish play an important role in the river ecosystem, including nutrient cycling, energy flow, and biodiversity maintenance. The construction of water conservancy projects destroys river connectivity, interferes with fish habitats, and blocks the normal swimming rhythm of migratory fish, which may lead to the dysfunction of the entire ecosystem and affect the survival of other organisms and the health of the entire ecosystem.

[0003] Juvenile fish of many fish species have a need for downstream migration, and the interference of the dam on the downstream process of juvenile fish has received wide attention. To help fish cross the dam safely and reach the downstream habitat, most water conservancy projects build fish passage facilities to assist the downstream movement of fish. Such as downstream bypass systems, fish-friendly turbines, spillways, fishways, fish collection and transportation systems, and other auxiliary technologies. These methods often cause certain harm to the fish body. According to relevant literature, downstream through the spillway often causes harm to downstream fish due to the too high dissolved oxygen concentration in the water body below the dam, thus reducing their swimming ability; the direct injury rate of the turbine to the fish body is as high as 10-20% due to the high flow velocity. The fish collection and transportation system consumes a lot of manpower, has low fish passage efficiency, and is slowly promoted; the lock is generally in a quasi-static water state, which is difficult to attract fish, and the number of fish passing through is small.

[0004] At present, the research on fish downstream dam crossing technology in China mainly focuses on the behavioral analysis of juvenile fish in response to accelerating flow and the use of physical fish guiding facilities, while there is less research on the monitoring of the species number after successful downstream migration of fish under natural conditions. The dam water replenishing channel is close to the fishway and is arranged in a bent shape. There is no energy dissipation facility in the water replenishing channel and it will not pose a threat or harm to the downstream juvenile fish. Moreover, replenishing water at the fishway inlet has the effect of enhancing the water flow to attract fish. Collecting data on the downstream movement of fish in the water replenishing channel under natural conditions is crucial for formulating effective protection strategies.

[0005] Although water conservancy projects bring multiple social and economic benefits, they destroy river ecological connectivity and affect fish migration, especially the downstream process of juvenile fish, posing a threat to ecological health. To mitigate the impact, various fish passage facilities have been developed, but there are problems of efficiency and ecological suitability. In particular, a water replenishing channel that is safe and friendly to juvenile fish has become the research focus, and its usage data under natural conditions is crucial for improving fish protection strategies. Summary of the invention

[0006] In view of the problems in the above-mentioned prior art, the utility model provides a fish collecting device for evaluating the downward efficiency of fish in a water replenishment channel under natural conditions, and its technical solution is: it includes a gate pier, a blocking net is arranged at the gate pier outlet, a plurality of bars are arranged on the upper part of both sides of the blocking net, a tension net is arranged on the lower part and the bottom surface of both sides of the blocking net, a collecting cage is arranged at the outlet of the blocking net, and the outlet of the collecting cage is movably connected to the intercepting net.

[0007] As a preferred solution, the grid bars are arranged transversely along the direction of water flow.

[0008] As a preferred solution, the inlet of the collecting cage is a funnel-shaped structure.

[0009] As a preferred solution, the height of the collecting cage is greater than or equal to the height of the net stretched on the side of the blocking net.

[0010] As a preferred solution, the inlet width of the barrier is larger than the outlet width, forming an eight-shaped structure.

[0011] Beneficial effects of the utility model:

[0012] (1) The bars and nets of the device prevent fish from being injured in the process of guiding them to the collection cage, thus reducing the abnormal mortality of fish;

[0013] (2) The inlet of the collecting cage of the device is a funnel-shaped structure, which prevents the collected fish from losing their way due to excessive water flow and turning back through the original inlet, thereby improving the collection success rate and accurately counting the species and morphological indicators of the downstream fish. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a top view of the utility model in actual situation.

[0015] Figure 2 It is a schematic diagram of the overall structure of the utility model.

[0016] Figure 3 It is a structural schematic diagram of the barrier net in the utility model.

[0017] Figure 4 It is a result schematic diagram of the collection cage in the utility model.

[0018] In the figure: 1. gate pier; 2. blocking net; 201. fence; 202. net; 3. collection cage; 4. interception net. DETAILED DESCRIPTION

[0019] The utility model is further described in detail below based on the accompanying drawings and specific embodiments.

[0020] Example

[0021] As Figures 1-3 shown, the fish collecting device for evaluating the downstream efficiency of fish in the water replenishment channel under natural conditions includes a pier 1. A retaining net 2 is arranged at the outlet of the pier 1. Several grid bars 201 are arranged on the upper half parts on both sides of the retaining net 2. A spreading net 202 is arranged on the lower half parts and the bottom surface on both sides of the retaining net 2. A collecting cage 3 is arranged at the outlet of the retaining net 2. The outlet of the collecting cage 3 is movably connected to an intercepting net 4. The number and the spacing between the grid bars 201 are comprehensively considered according to the morphological data of the fish passing target.

[0022] Furthermore, the grid bars 201 are arranged horizontally along the water flow direction. Under the same hydraulic conditions, the efficiency of the horizontally arranged grid bars in intercepting juvenile fish is higher than that of the vertically arranged grid bars.

[0023] Furthermore, the inlet of the collecting cage 3 is of a funnel-shaped structure, and the funnel-shaped structure can prevent fish from getting lost due to excessive water flow and having a turning-back behavior.

[0024] Furthermore, the height of the collecting cage 3 is greater than or equal to the height of the spreading net 202 on the side surface of the retaining net 2, increasing the probability of fish entering the collecting cage 3.

[0025] Furthermore, the inlet width of the retaining net 2 is larger than the outlet width, presenting an eight-shaped structure, gradually narrowing the activity area of the fish and guiding the fish into the collecting cage 3.

[0026] When the above device is used, the using process is as follows: The retaining net 2 is arranged at the outlet of the pier 1 to form a retention area. When it is necessary to record the data of the downstream fish, the collecting cage 3 is placed at the outlet of the retaining net 2 and connected by a binding method, and the intercepting net 4 is bound to the outlet of the collecting cage 3. Wait for the fish that have successfully descended under natural conditions to enter the collecting cage 3. After the waiting time ends, take out the collecting cage 3 to record the data. This device has a good intercepting and guiding effect on the middle and lower layer fish, providing important support for the study of the downstream of the middle and lower layer fish.

Claims

1. A fish gathering device for evaluating the fish migration efficiency of a water replenishment channel under natural conditions, comprising a gate pier (1), characterized in that: A blocking net (2) is arranged at the exit of the gate pier (1), a plurality of bars (201) are arranged at the upper parts of both sides of the blocking net (2), a tension net (202) is arranged at the lower parts and the bottom surface of both sides of the blocking net (2), a collecting cage (3) is arranged at the exit of the blocking net (2), and the exit of the collecting cage (3) is movably connected to the intercepting net (4).

2. The fish gathering device based on evaluating the fish descending efficiency of the water replenishment channel under natural conditions according to claim 1 is characterized in that: The grating bars (201) are arranged transversely along the direction of water flow.

3. The fish gathering device based on evaluating the fish descending efficiency of the water replenishment channel under natural conditions according to claim 1 is characterized in that: The inlet of the collecting cage (3) is a funnel-shaped structure.

4. The fish gathering device for evaluating the fish descending efficiency of the water replenishment channel under natural conditions according to claim 1 is characterized in that: The height of the collecting cage (3) is greater than or equal to the height of the stretched net (202) on the side of the blocking net (2).

5. The fish gathering device for evaluating the fish descending efficiency of the water replenishment channel under natural conditions according to claim 1 is characterized in that: The inlet width of the barrier net (2) is larger than the outlet width, and has an eight-shaped structure.

Images