JP3748391B2 - Floor firming cascade fishway - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fishway provided in a river, and more particularly to a cascade-type fishway that allows fish to sufficiently run up even when the river flow rate is equal to or lower than a plain water flow rate.
[0002]
[Prior art]
Conventionally, rivers have been provided with dams of various sizes for the purpose of water intake. In this case, a fishway is provided at a considerable cost so that the fish can be run up, but there are few cases where it can be said that this fishway is functioning sufficiently effectively. In particular, in the case of large-scale weirs such as movable weirs, there are issues to be solved from the viewpoint of river environmental conservation and the formation of a hydrophilic environment, despite the high construction and maintenance costs. It often occurs.
[0003]
Therefore, the present inventors have conducted a variety of studies on a fishway that is low in construction cost, easy to maintain, and suitable from the viewpoint of environmental conservation and hydrophilic environment formation. As a result, the floor compaction dam part, the water cushion part, and the deflector part If at least one cascade is provided, and a part of each top of the dam and the deflector is provided with a cutout so that water flows even if the river flow rate is equal to or less than the normal water flow rate, it is extremely In addition to being effective, the present inventors have found that the water cushion portion is useful for forming a hydrophilic environment, and reached the present invention.
[0004]
[Problems to be solved by the invention]
Accordingly, a first object of the present invention is to provide a river fishway that is inexpensive and effective from the viewpoint of environmental conservation.
The second object of the present invention is to provide an inexpensive and effective fishway that can compensate for the hydrophilic environment destroyed by the construction of a dam.
[0005]
[Means for Solving the Problems]
The above-mentioned objects of the present invention are to provide at least one cascade work having a floor compaction dam part, a slope part, a water cushion part, and a deflector part, and a line connecting each top part of the floor compaction dam part and the deflector part is a planned river bed It is a fishway that is placed between the upstream side and the downstream side, so that the fish can run up even if the river flow is below the flat water flow, so that the fish can run up. This has been achieved by a floor consolidation cascade type fishway characterized in that at least one notch having a required depth and width is provided at any location on the top of each floor of the construction floor consolidation dam and the deflector.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited by this.
FIG. 1 is a conceptual cross-sectional view of an embodiment in the case where the floor-sealed cascade type fishway of the present invention is connected in three stages. In the figure, reference numeral 1 is the planned riverbed vertical line, 2 is the paragraph length, 3 is the floor compaction dam, 4 and 4 'are the water cushion portions, 5 is the deflector, 6 is the paragraph height, and 7 is the water cushion depth (deflector height). ) 8 is an upstream grate, 9 is a downstream grate, 10 is a water intake opening provided as required, 11 is a water conduit, θ ₁ is a slope angle of a paragraph, and θ ₂ is a deflector rising The slope angle, L is the horizontal bottom length of the water cushion, B is the full width of the fishway, and B 'is the width of the fishway opening.
[0007]
Each dam 3 has a slope with a slope slope angle θ ₁ on the downstream side so that fish can easily go up, and the water cushion portion 4 develops on the tip (downstream side) of the slope. The water cushion part 4 has a function of the waterfall of the population, and the water cushion part 4 is not buried with earth and sand so that the waterfall is not buried with earth and sand.
The paragraph height 6 is determined by the number of stages of the floor consolidation cascade type fishway of the present invention with respect to the planned riverbed vertical line 1 and the paragraph length 2. Usually, the paragraph height 6 is 1 m to 1.3 m. is there. The paragraph slope inclination angle θ ₁ is preferably 40 ° to 65 ° so that the fish that can be expected to run up can easily go up, but it is particularly preferably 45 ° to 60 °. Most preferably, it is about 50 °.
[0008]
Water moss or the like grows on the water cushion portion 4 and can serve as a food for fish stagnating during the run-up. In addition, the design flow rate for determining the hydraulic specifications of the water cushion is about 1/5 of the planned high water volume, but its depth 7 (deflector height) is particularly 0 from the viewpoint of functioning as a children's water playground. It is preferable to set it to 3 m to 0.5 m. In addition, if this depth is secured, it is suitable for forming a waterside environment because inhabiting fish are not easily attacked by birds. Further, the water cushion horizontal bottom floor length L is preferably 1.5 to 2.0 times the paragraph height 6.
[0009]
Deflector inclination angle theta ₂ of the upward slope creep is preferably about 20 ° to 25 °. In addition, the downstream end of the fishway of the present invention is provided with a water cushion portion 4 ′ having a block, a jar, a futon cage or the like arranged at the bottom in order to prevent scouring and to form a stagnant area for upstream fish. It is preferable to provide it.
On the other hand, it is preferable to provide a water guide pipe 11 for taking in river bed reservoir water in the most upstream bed compacting dam and drain the back of the dam together with the water intake.
[0010]
The fishway of the present invention is generally made of a concrete structure. However, in areas where appropriate stone materials are available, it is easy to adapt to the natural environment by applying a stone wall or masonry structure to prevent wear. can do. Moreover, when constructing the fishway of the present invention on the water-permeable ground (river bed), it is necessary to make the length sufficient to ensure a sufficient permeation path length as the paragraph length.
[0011]
The greatest feature of the fishway of the present invention is that each dam and the deflector have a notch 12 having a depth and width necessary for the upstream of the fish so that the upstream of the fish is not hindered even if the river flow is low. It is in the point provided. The depth of the notch is equal to or greater than the height of the assumed height of the rising fish plus the height of the back fin, and the width of the notch is equal to or greater than 1/2 of the assumed length of the ascending fish. In addition, the position of the opening may be on one side or both sides of the river depending on the topography and flow conditions of the river, and it can be in the center of the river, and the number is also particularly limited It's not that.
[0012]
In the most upstream cascade work, a water intake (opening) 10 can be provided on the side wall of the water cushion according to the amount of water intake, if necessary. In addition, it is preferable to provide a water control gate at the intake port so that the intake port can be opened and closed and the amount of intake water can be adjusted. As described above, the fishway of the present invention is characterized in that the fishway is mainly designed in consideration of the river environment and flow conditions, and a water intake facility is provided incidentally.
[0013]
【The invention's effect】
The floor-sealing cascade type fishway of the present invention is designed mainly with a fishway in consideration of the river environment and flow conditions, so that river environment conservation and formation of a hydrophilic environment can be sufficiently achieved. If the river water flow rate is equal to or higher than the flat water flow rate, not only the notch part but also the entire width of the cascade works as a fishway. This ensures that the fish will not be prevented from going up all the time.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic cross-sectional view of an embodiment in which three floor-sealed cascade type fishways of the present invention are connected.
FIG. 2 is a plan view of the embodiment of FIG.
3 is a cross-sectional view taken along line AA and BB of the embodiment shown in FIG.
[Brief description of symbols]
1. Planned riverbed vertical line 2. Paragraph length 3. 3. Floor hardening dam 4. Water cushion 4 '. 4. Water cushion Deflector 6. Paragraph height 7. Water cushion depth (deflector height)
8). 8. Upstream side glove 9 Downstream side floor protection work10. Intake opening 11. Water conduit 12. Notch θ ₁ . Paragraph slope inclination angle θ ₂ . Deflector climbing slope slope angle L. Horizontal bottom length of water cushion Full width of fishway B '. Fishway opening width

Claims (10)

At least one cascade work having a floor dam part, a slope part, a water cushion part, and a deflector part, so that the line connecting each head part of the floor dam part and the deflector part is below the planned river bed vertical line It is a fishway that is arranged between the floor protection work and the downstream side protection work, so that the fish can run up even if the river flow rate is less than the flat water flow rate. A floor-sealing cascade type fishway characterized in that at least one notch having a necessary depth and width is provided at any part of the top of the head. The floor consolidation cascade type fishway according to claim 1, wherein the cascade construction is connected in two or more stages. The floor consolidation cascade type fishway according to claim 2, wherein the most upstream cascade work has a water intake on one side wall of the water cushion portion. The floor-sealing cascade type fishway according to claim 3, wherein a water control gate is arranged at the intake. The floor consolidation cascade type fishway according to any one of claims 1 to 4, wherein a difference between a top height of the floor consolidation dam and a top height of the deflector is 0.4 to 0.8 m. The floor-sealed cascade type fishway according to any one of claims 1 to 5, wherein the depth of the cutout is a depth equal to or higher than a height obtained by adding a dorsal fin height to a body height of an assumed upstream fish. Inclination angle theta ₁ of the inclined surface portion is approximately 40 ° to 65 °, according to any one of claims 1 to 6 the floor compaction cascade method fishway. The floor consolidation cascade type fishway according to any one of claims 1 to 7, wherein the horizontal bottom floor length L of the water cushion portion is about 1.5 to 2.0 times the height of the floor consolidation dam paragraph. Inclination angle theta ₂ of the deflector portion creeping up the inclined surface is about 20 ° to 25 °, according to any one of claims 1 to 8 the bed compaction cascade method fishway. The floor consolidation cascade type fishway according to any one of claims 1 to 9, wherein a water conduit for taking in riverbed reservoir water is arranged on the most upstream floor consolidation dam.

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