JP4959543B2 - Bird protection equipment - Google Patents

Description

  The present invention relates to a birdproof device for protecting fishes that pass through a fishway provided in a dam or a weir from birds.

  Conventionally, when constructing weirs and dams in rivers, a fishway connecting the upstream and downstream sides of the weirs and dams has been established so that fish can run upstream from the downstream side of these weirs and dams. Yes. However, such a fishway has a narrow river width, and when the fish pass, it is preyed by birds.

Therefore, in order to protect the fish passing through the fishway from birds, for example, in Patent Document 1, support members are installed upstream and downstream of the fishway, and between these support members, the height near the surface of the fishway is increased. Further, it is described that a plurality of bird-proof threads are stretched.
JP 2006-158277 A

  However, in the method described in Patent Document 1, when the water level of the fishway rises, part of the bird's thread is submerged, and the fish may be preyed on by this bird. In addition, when the water level of the fishway is lowered, the bird's thread is separated from the surface of the water, so that birds enter the lower part of the bird's thread and there is a risk that the fish will be preyed. For this reason, when the water level of the fishway changes, the worker pulls up the support member with a rope or the like to adjust the height of the bird protection thread when the water level of the fishway changes so as to keep the height of the bird protection thread at a substantially constant height from the water surface. I had to do it and it took a lot of work.

  The present invention has been made in view of the above problems, and its purpose is to maintain the height of the bird-proof thread at a substantially constant height from the water surface in accordance with the water level of the fishway without depending on human power. Is to do.

  The bird protection device of the present invention is a bird protection device in which a plurality of bird protection yarns are stretched above a fish passage for allowing fish to pass so as to extend in the direction of the flow of the fish passage at intervals in the width direction. And at least one end of the said bird-proof thread is connected to the float member which floats in the said fishway, It is characterized by the above-mentioned.

  Moreover, said bird-proof apparatus may be provided with the mechanism which applies tension | tensile_strength to the said bird-proof thread.

  According to the present invention, since the end of the bird's thread is attached to the float, even if the water surface of the fishway rises and falls, the float rises and falls accordingly, and The height can be kept substantially constant.

Hereinafter, an embodiment of a birdproof device of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a plan view showing a fishway 20 to which a birdproof device of the present embodiment is attached. As shown in the figure, the fishway 20 is a water channel provided so that fish can go up from the downstream side of the dam 10 to the upstream side, and is separated from the side of the river downstream of the dam 10. The bent portion 50 is bent so as to reach the upstream side 60 of the dam 10. The birdproof device of this embodiment is for protecting the fish which pass the fishway 20 from the predation by birds in such a fishway 20.

  FIG. 2 shows the configuration of the birdproof device 30 of the present embodiment, in which (A) is a vertical sectional view and (B) is a plan view. Although the bird protection device 30 provided in the section from the downstream side of the dam 10 to the turn-up portion 50 is shown in the same figure, a device similar to this is provided from the turn-up portion 50 to the upstream side 60 of the dam 10. It is also provided in the section up to. As shown in FIG. 2, the bird protection device 30 includes a float 32, a plurality of bird protection yarns 31 having one end attached to the float 32, and first to first guides the bird protection yarn 32 to above the wall surface of the dam 10. The third pulleys 36, 37, and 39, and the weight 40 attached to the portion of the bird's proof yarn 32 that is suspended from the third pulley 39 attached above the wall surface of the dam.

  The plurality of bird-proof threads 31 have a predetermined height (for example, from the water surface of the fishway 20 so that the birds that try to prey on the fish that pass through the fishway 20 come into contact with the trunks and wings of the birds when they approach the fishway 20. , About 50 cm) with a predetermined interval (for example, about 50 cm) that prevents birds from passing in the width direction.

  The float 32 is guided in the vertical direction by the guide mechanism 38. The guide mechanism 38 includes a rail 34 attached to the wall surface of the dam and a roller 33 to which the float 32 is connected and which is guided by the rail 34 and can move only in the vertical direction. When the water level of the fishway 20 changes, the float 32 moves up and down while being guided by the guide mechanism 38 accordingly.

  The plurality of bird-proof threads 31 extend from the float 32 to a plurality of first pulleys 36 corresponding to the respective bird-proof threads 31 attached to a support member 35 extending in the width direction of the fishway 20. The plurality of bird-proof yarns 31 are grouped together, and the grouped bird-proof yarns 31 extend from the second pulley 37 to the third pulley 39 installed on the upper surface of the dam wall, The thread 31 hangs down from the third pulley 39. A weight 40 is attached to the tip of the bird-proof thread 31 that hangs down from the third pulley 39. Due to the weight of the weight 40, a tensile force is always applied to the bird-proof thread 31.

  FIG. 3 is a diagram showing the bird protection apparatus 20 in a state where the amount of water in the fishway 5 has increased and the water surface has risen. As shown in the figure, when the amount of water in the fishway 5 increases and the water level rises, the float 32 rises accordingly. And when the float 32 rises, the bird-proof thread 31 connected to the float 32 also rises, and the bird-proof thread 31 is kept at a substantially constant height from the water surface. As the float 32 rises, the distance between the float 32 and the first pulley 37 is shortened. However, as described above, the tensile force due to the weight of the weight 40 is always applied to the bird-proof yarn 31. Therefore, no sagging occurs.

  FIG. 4 is a diagram showing the bird protection apparatus 20 in a state where the amount of water in the fishway 5 is reduced and the water surface is lowered. As shown in the figure, when the amount of water in the fishway 5 decreases and the water surface descends, the float 32 also descends. As the float 32 descends, the bird-proof thread 31 connected to the float 32 also descends, and the bird-proof thread 31 is kept at a substantially constant height from the water surface.

  As described above, according to the birdproof device 30 of the present embodiment, the float 32 moves up or down in accordance with the change in the water level of the fishway 5, so that the birdcage thread 31 whose end is connected to the float 32. The height also changes. In this way, even if the water level of the fishway 5 changes, the bird-proof thread 31 is automatically maintained at a substantially constant height, so there is no need to adjust the height of the bird-proof thread 5 by a human hand. It is possible to reduce work time.

  In the present embodiment, the bird-proof yarn 31 extends upward from the wall surface of the dam via the second pulley 37, and the third pulley 39 of the bird-proof yarn 31 reaching the upper side of the wall surface of the dam. However, the present invention is not limited to this, and the bird-proof yarn 31 extends vertically downward via the second pulley 37 as shown in FIG. The weight 40 may be attached to the tip of the bird-proof yarn 31 extending vertically downward via the second pulley 37.

  In the present embodiment, the downstream end of the bird-proof thread 31 is connected to the float 32. However, the present invention is not limited thereto, and the float 32 is guided in the vertical direction by the guide mechanism on the upstream side of the fishway 20. It is good also as a structure which attaches the upstream edge part of the bird-proof thread 31 to this float 32. In this case, for example, pulleys are provided above and below the dam 10, and the downstream end of the bird protection yarn 31 is guided toward the upper side of the dam 10 by the lower pulley, and further provided above the dam 10. It is possible to apply tension to the bird-proof thread 31 by hanging it down through a pulley and attaching a weight to its lower end.

  Furthermore, it is good also as a structure which provides the float 32 guided to an up-down direction by the guide mechanism in the upstream and downstream of the fishway 20, and tensions the bird-proof thread 31 between these floats 32. In this case, for example, a pulley is attached to the float 32 on the upstream side, and the upstream end of the bird's proof yarn 31 is guided above the dam 10 by this pulley, and further suspended from the pulley attached above the dam 10. Then, tension can be applied to the bird-proof thread 31 by attaching a weight to its lower end.

It is a top view which shows the fishway to which the bird-proof apparatus of this embodiment is attached. The structure of the bird-proof apparatus of this embodiment is shown, (A) is a vertical sectional view, (B) is a plan view. It is a figure which shows the bird-proof apparatus in the state which the water quantity of the fishway increased and the water surface rose. It is a figure which shows the bird-proof apparatus in the state which the water quantity of the fishway decreased and the water surface fell. It is a figure which shows the bird-proof apparatus at the time of attaching a weight to the front-end | tip of the bird-proof thread extended perpendicularly downward from a 2nd pulley.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Dam 20 Fishway 30 Bird-proof device 31 Bird-proof thread 32 Float 33 Roller 34 Rail 35 Support member 36 First pulley 37 Second pulley 38 Guide mechanism 39 Third pulley 40 Weight

Claims (2)

Above the fishway for allowing fish to pass through, a birdproof device in which a plurality of birdstrings are stretched so as to extend in the direction of the flow of the fishway at intervals in the width direction,
At least one end of the bird-proof thread is connected to a float member that floats on the fishway.   2. The bird protection apparatus according to claim 1, further comprising a mechanism for applying tension to the bird protection thread.

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