JP2000257052A - Fishpass block - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow fish to go upstream easily over dams and banks at positions where there is a head in water level between an upstream side and a downstream side such as dams and banks. SOLUTION: A fishpass 6 formed as an inclined surface having a specified angle relative to a horizontal plane in the state of being installed is provided on an upper surface part,and a water reserving recessed part 4 allowing fish to take a rest is provided midway in the fishpass 6. The fishpass 6 comprises a flow-in side fishpass 6a to allow water to flow into the water reserving recessed part 4 and a flow-out side fishpass 6b to allow water to flow out of the water reserving recessed part 4. The flow-in side fishpass 6a and flow-out side fishpass 6b are disposed so as to be deviated from each other generally in horizontal direction crossing at right angles with the water flow direction as viewed from the upper side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fishway block for forming a fishway through which fish can go upstream over a dam or the like for spawning, for example, in a river or a waterway provided with a dam. About.

[0002]

2. Description of the Related Art When a river has waterfalls, dams, and dams, an inclined surface is provided on the downstream side of the dams, for example, in order to prevent fish that are going to go upstream for spawning to stop there. It is conceivable that the slope is formed as a fishway, and the fish can easily go back through the fishway. Therefore, the angle of inclination of the fishway needs to be relatively small so that the fish can go back.

[0003]

However, when the difference between the water level on the upstream side and the water level on the downstream side of the embankment, that is, when the head is relatively large, the inclination angle of the fishway can be reduced to reduce the length of the fishway. The length of the fishway may be too long to allow the fish to pass through the fishway, and the longer the fishway, the higher the construction cost. Of course, if the angle of inclination of the fishway is increased, it becomes difficult for fish to trace the fishway.

[0004] It is an object of the present invention to provide a fishway block in which fish can easily go back and can be inexpensively constructed in a place where there is a drop in water level between the upstream side and the downstream side, such as a dam. I do.

[0005]

According to a first aspect of the present invention, there is provided a fishway block having a fishway formed on an upper surface of the fishway block and having a predetermined angle with respect to a horizontal plane in an installed state. Is provided with a water reservoir recess capable of resting. The fishway block according to a second aspect of the present invention is the fishway block according to the first aspect, wherein the fishway includes an inflow-side fishway for allowing water to flow into the reservoir recess and an outflow-side fishway for allowing water to flow out of the reservoir recess. Wherein the inflow-side fishway and the outflow-side fishway are arranged so as to be shifted from each other in a substantially horizontal direction perpendicular to a direction in which water flows when viewed from above.

A fishway block according to a third invention is characterized in that, in the first or second invention, sidewalls are provided on both sides along the fishway. A fishway block according to a fourth invention is the fishway block according to the first, second, or third invention, wherein the fishway block comprises an upper block and a lower block, and the fishway is provided in the upper block. The side block is a hollow block that opens upward, has a drain hole at the bottom, and has an exhaust hole at the side wall.

[0007] The fishway block of the present invention can be installed on a riverbed downstream of, for example, a dam, so that water on the upstream side of the dam flows downstream through the fishway. As a result, the fish downstream of the dam or the like can be traced back to the upstream side of the dam through the fishway formed by the inclined surface. Further, since the water recess is provided in the middle of the fishway, the fish going upstream through the fishway can rest at the water recess. Then, when the water on the upstream side flows into the water reservoir concave portion through the fish passage, the water stored in the water reservoir concave portion foams, thereby dissolving oxygen in the air into the water stored in the water reservoir concave portion. be able to. Then, the water in which a large amount of oxygen accumulated in the water reservoir concave portion has dissolved overflows from the water reservoir concave portion and flows downstream through the fish passage.

According to the second aspect, the inflow-side fishway and the outflow-side fishway connected to the water reservoir recess are arranged so as to be shifted from each other in a substantially horizontal direction perpendicular to the direction of water flow when viewed from above. The momentum (flow velocity) of the flow of water on the upstream side that has flowed into the reservoir recess through the inflow-side fishway can be counteracted by the water retained in the reservoir recess, and the momentum of the water flow has been counteracted. The water in the sump recess can be drained downstream through the outflow fishway.

According to the third aspect of the invention, when the amount of water in a river or the like in which the fishway block is installed is small or normal, the upstream water can flow downstream through the fishway. When the amount of water in a river or the like is large, water can flow downstream so that water does not overflow from the upper surface of the fishway block by the side wall.

According to the fourth aspect, since the fishway block is divided into an upper block and a lower block, the weight of each block can be reduced as compared with the case where both are integrally formed. , The bulk can be reduced. And since the structure of the lower block is hollow, the weight can be reduced. In addition, since the lower block is provided with an exhaust hole and a drain hole, air collected in the hollow portion during construction can be discharged to the outside, and water flowing into the hollow portion can be removed from the upper block side. Instead, it can be drained toward the riverbed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a fishway block according to the present invention will be described with reference to the drawings. The fishway block of this embodiment is made of concrete, and is installed and used at the bottom (riverbed) of a river or waterway, for example, as shown in FIGS. 1 and 2. In the figure, 1 is a fishway block. The fishway block 1 includes a first upper block 1a and a second upper block 1b provided with a fishway 6;
And a lower block 21 installed below the first upper block 1a. Since the second upper block 1b is vertically symmetrical with respect to the first upper block 1a when viewed from the plan view of FIG. 2, the first upper block 1a will be described, and the second upper block 1b will be described. Omitted.

The first upper block 1a is shown in FIGS.
As shown in FIG. 1, the upper surface 2 of the main body 3 is formed by an inclined surface which descends toward the downstream side, and a water reservoir recess 4 is provided at a substantially central portion of the upper surface 2. FIG. 1 is a cross-sectional view as seen from the YY direction in FIG. 2, and as shown in FIG.
Is curved in an arc shape. FIG. 5 is an end view of the water reservoir recess 4 viewed from the ZZ direction in FIG. And
On the upper surface 2 of the first upper block 1a, as shown in the plan view of FIG. 2, the inflow side fishway 6a (6) for flowing water into the water reservoir recess 4 and the water flows out from the water reservoir recess 4. Outflow-side fishway 6b (6) is provided, and the inflow-side fishway 6a and the outflow-side fishway 6b are shifted from each other in a substantially horizontal direction orthogonal to the direction of water flow when viewed from above. . FIG. 6 is an end view of the inflow-side fishway 6a seen from the YY direction in FIG. 2, and the outflow-side fishway 6b has the same end face shape. As shown in FIG. 6 and the like, the first upper block 1a has side walls 7, 7 of a predetermined height on both side edges of the main body 3 along the inflow and outflow fishways 6a, 6b. It is provided. FIG. 3 is a front view of the first upper block 1a. FIG. 4 shows the first upper block 1a in FIG.
FIG. 4 is a cross-sectional view as viewed from the WW direction.

As shown in FIGS. 1 and 7, the lower block 21 is a hollow block having a rectangular planar shape and opening upward. Four drain holes 25 are formed in the bottom portion 22, and a pair of side wall portions 23 parallel to the fish passage 6 are provided with the respective side wall portions 23 at a position near the bottom portion 22 and at an upper position. A total of ten exhaust holes 27 and a total of four exhaust holes 28 are formed. As shown in FIG. 7, a step 30 is provided on the inner peripheral edge of the upper end of the side wall 23 of the lower block 21. This step portion 30
As shown in FIG. 1, the first upper block 1a and the lower block 21 are displaced in the horizontal direction by fitting with the protrusion 9 projecting from the lower surface of the first upper block 1a. It is not to be. Further, as shown in FIG. 1, a concave portion 8 is provided at an end on the water inflow side of the first upper block 1a, and a convex portion 10 is provided on an end on the water outflow side.
Is provided. When the first upper block 1a and the second upper block 1b are connected to each other, as shown in FIG.
Are fitted to each other so that they do not shift in the horizontal and vertical directions. As shown in FIG. 6, the first upper block 1a is provided with a hanging hardware locking hole 11 and a hanging hardware locking hole 12. These holes 11 and 12
Is used to suspend the first upper block 1a with a crane or the like when installing the first upper block 1a. Also,
As shown in FIG. 1, when the lower block 21 is installed, a hollow portion (inside) thereof is filled with chestnut stone.

Next, a procedure for installing the fishway block 1 configured as described above will be described with reference to FIG. First, the lower block 21 is installed on the riverbed R with the lower block 21 in contact with the downstream side surface of the bank M. Next, the second upper block 1b is installed downstream of the lower block 21. After a while, the first
Is set on the lower block 21.
According to the fishway block 1 installed in this way, the dam M
Outflow-side fishway 6b, water-reservoir recess 4, and inflow-side fishway 6 provided in the second and first upper blocks 1b and 1a formed by inclined surfaces with fish that inhabit downstream thereof.
a can be sequentially traced back to the upstream side, and the eggs can be laid on the upstream side. Since the water recesses 4 are provided at two places in the middle of the fishway 1, the fish going to the upstream through the fishway 1 can rest in each of the water recesses 4. You can definitely reach the side. Then, the water on the upstream side flows into the reservoir recess 4 through the inflow-side fish passage 6a, so that the water reservoir recess 4 is formed.
The water remaining in the reservoir can be bubbled to dissolve oxygen in the air, thereby effectively reducing fatigue of fish resting in the reservoir recess 4. Further, the water containing a large amount of oxygen can be discharged to the downstream side.

Further, the inflow-side fishway 6a and the outflow-side fishway 6b connected to each of the water reservoir recesses 4 are arranged so as to be displaced from each other in a substantially horizontal direction perpendicular to the direction in which water flows when viewed from above. The momentum (flow velocity) of the flow of water on the upstream side that has flowed into the reservoir recess 4 through the inflow-side fishway 6a can be counteracted by the water accumulated in the reservoir recess 4, and the momentum of the water flow is canceled. The water in the pool sump recess 4 can be discharged downstream through the outflow fishway 6b. Therefore, the momentum of the water flowing through the inflow-side and outflow-side fishways 6a and 6b can be reduced, so that the fish can travel in this fishway 1
Can be easily traced back.

Further, when the amount of water in a river or the like in which the fishway block 1 is installed is small or almost normal,
By flowing upstream water downstream through a relatively narrow fishway, the depth of the fishway becomes deeper, so that downstream fish can travel upstream through this fishway 1. And
When the amount of water in a river or the like is large, the water can be prevented from overflowing from the fishway block 1 by the side walls 7 and 7, so that the fish heads upstream through the water channel surrounded by the side walls 7 and 7. be able to. That is, if water overflows from the fishway block 1, it is difficult for the fish to reach the upstream side, but it is possible to reach the upstream side by preventing the water from overflowing.

Since the fishway block 1 is divided into the first and second upper blocks 1a and 1b and the lower block 21, the weight of each of the blocks 1a, 1b and 21 can be reduced. , The bulk can be reduced. As a result, the production and construction can be performed relatively easily as compared with the case where both are integrated. Since the lower block 21 is provided with the exhaust holes 27 and 28, the air accumulated in the hollow portion of the lower block 21 at the time of construction can be discharged to the outside. 1a can be prevented from receiving a force in the direction in which it floats due to the air accumulated in the hollow portion.
Further, the water flowing into the hollow portion is removed by the first upper block 1.
Since the water can be drained from the drain hole 25 toward the riverbed R instead of the side a, the flowing force of the water that has flowed into the hollow portion does not act as a force for lifting the first upper block 1a. be able to. by this,
The fishway block can be installed stably.

The angle of inclination of the fishways 6a, 6b shown in FIG. 1 is 15 ° to 20 °, the head difference between the upstream and downstream water levels is about 60 cm, the first upper block 1a, the second upper block 1b, The length of each of the lower block 21 and the lower block 21 in the direction in which water flows is about 210 cm, but other angles and lengths may be used.

However, in the above embodiment, as shown in FIG. 1, the fishway block 1 is provided with the two water recesses 4, but one or more water recesses 4 are provided along the fishway 6. It is good also as a structure provided. And although the said fishway block 1 was made into the structure which consists of three blocks of the 1st upper block 1a, the 2nd upper block 1b, and the lower block 21, it is other than this, 1, 2, or 4 or more. It may be configured with a number of blocks. Further, the fishway blocks 1 shown in the above embodiment may be installed in a plurality of rows along the bank M. Furthermore, in the above embodiment, the fishway block 1 is applied to the dam M. However, the fishway block 1 is provided at a location other than the dam M, for example, where a waterfall or dam is located, and fish downstream of the waterfall or dam trace upstream to the waterfall or the like. Can be done.

[0020]

The fishway block of the present invention can be installed, for example, on a downstream riverbed such as a dam, so that water on the upstream side of the dam flows downstream through the fishway. According to the fishway block installed in this way, even if the angle of inclination of the fishway is reduced and the length of the fishway becomes longer, the fishway becomes longer when the head difference between the water level on the upstream side and the water level on the downstream side is relatively large. The recess in the water reservoir provided in the middle of the river serves as a place for resting the fish, so that the fish on the downstream side can easily reach the upstream side of the bank through this fishway. This can contribute to fish spawning. Even when the angle of the fishway is slightly increased and its length is shortened in order to reduce the size of the fishway block, similar to the above, the reservoir recess becomes a resting place for fish, and the fish on the downstream side You can easily reach the upstream side. As described above, when the fishway block is reduced in size, manufacturing and construction are facilitated, and the cost of each can be reduced. In addition, when the water on the upstream side flows into the water reservoir recess through the fishway, the water stored in the water reservoir recess can be bubbled to dissolve the oxygen in the air, thereby resting in the water reservoir recess. It is possible to effectively reduce the fatigue of the fish. Further, since the water containing a large amount of oxygen flows to the downstream side, it can also contribute to the growth of fish on the downstream side.

According to the second aspect of the present invention, when the length of the fishway becomes longer or the head between the entrance and the exit of the fishway increases, the momentum of the water flowing from the entrance of the fishway becomes considerably stronger when flowing out of the exit of the fishway. The momentum of this water can be reduced. In other words, the momentum (flow velocity) of the flow of water on the upstream side that has flowed into the sump recess through the inflow-side fishway can be counteracted by the water accumulated in the sump recess, and the momentum of the flow of water has been canceled. The water in the sump recess can be drained downstream through the outflow fishway. Therefore,
The momentum of the water flowing through the inflow and outflow fishways can be reduced, thereby making it easier for fish to trace these fishways.

According to the third aspect of the present invention, when the amount of water in a river or the like in which the fishway block is installed is small or normal, the water on the upstream side is made to flow downstream through the relatively narrow fishway, thereby reducing the size of the fishway. The depth of the water becomes deeper, so that downstream fish can travel upstream through this fishway. When the amount of water in a river or the like is large, water can be prevented from overflowing from the upper surface of the fishway block by the side wall, so that the fish can travel upstream through the water channel surrounded by the side wall. . That is, if water overflows from the fishway block, it is difficult for the fish to reach the upstream side, but it is possible to reach the upstream side by preventing the water from overflowing.

According to the fourth aspect, since the fishway block is divided into an upper block and a lower block, the weight of each block can be reduced and the bulk can be reduced. As a result, manufacturing and construction can be performed relatively easily as compared with the integrated type. And
Since the lower block is provided with an exhaust hole, air collected in the hollow portion of the lower block during construction can be discharged to the outside, whereby the upper block is lifted by the air collected in the hollow portion. You can avoid receiving the power of. In addition, since the water that has flowed into the hollow can be drained from the drain hole toward the riverbed rather than toward the upper block, the flowing force of the water that has flowed into the hollow is a force that lifts the upper block. You can prevent it from working. Thus, the fishway block can be stably installed.

[Brief description of the drawings]

FIG. 1 shows a fishway block according to one embodiment of the present invention.
It is sectional drawing seen from the XX direction of FIG.

FIG. 2 is a plan view of a fishway block according to the embodiment.

FIG. 3 is a first view of the fishway block according to the embodiment;
It is a front view of the upper block of FIG.

FIG. 4 is a cross-sectional view of the first upper block according to the embodiment as viewed from the WW direction in FIG. 2;

FIG. 5 is an end view of the first upper block according to the embodiment as viewed from the ZZ direction in FIG. 2;

FIG. 6 is an end view of the first upper block according to the embodiment as viewed from the YY direction in FIG. 2;

FIGS. 7A and 7B are views showing a lower block constituting the fishway block according to the embodiment, wherein FIG. 7A is a plan view, FIG. 7B is a cross-sectional view as viewed from the AA direction of FIG. (c) is a sectional view as seen from the BB direction of (a).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fishway block 1a 1st upper fishway block 1b 2nd upper fishway block 2 Inclined upper surface 4 Reservoir recess 6 Fishway 6a Inlet side fishway 6b Outlet side fishway 7 Side wall 21 Lower block 25 Drainage hole 27, 28 Exhaust hole

Claims (4)

[Claims] 1. A fish passage formed as an inclined surface forming a predetermined angle with respect to a horizontal plane in an installed state is provided on an upper surface portion, and a water reservoir recess in which fish can rest is provided in the middle of the fish passage. Fishway block. 2. The fishway block according to claim 1, wherein the fishway includes an inflow-side fishway for flowing water into the reservoir recess and an outflow-side fishway for flowing water from the reservoir recess. A fishway block, wherein the inflow-side fishway and the outflow-side fishway are shifted from each other in a substantially horizontal direction orthogonal to a direction in which water flows when viewed from above. 3. The fishway block according to claim 1, wherein side walls are provided on both sides along the fishway. 4. The fishway block according to claim 1, 2 or 3, wherein the fishway block comprises an upper block and a lower block, wherein the upper block is provided with the fishway, and the lower block is A fishway block, which is a hollow block opening upward, having a drain hole at the bottom and an exhaust hole at the side wall.