JP3205704B2 - Spiral fishway - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a river dam, weir,
The present invention relates to a fishway which is attached to a headwork or the like to enable aquatic organisms such as fish to go upstream.

[0002]

2. Description of the Related Art A spiral fishway is known as a fishway with a large height difference in a small space. The conventional spiral fishway was constructed so as to simply go up in an arc shape and rise, so that the planar shape was circular.

[0003]

In such a spiral fishway having a circular planar shape, the water flowing in from the uppermost fishway outlet is accelerated more and more with centrifugal force as it descends. The flow velocity at the entrance of the fishway becomes very large. For this reason, it was difficult to obtain the most favorable flow velocity (preferred flow velocity) for fish that run upstream.

Accordingly, an object of the present invention is to provide a spiral fishway capable of reducing the flow velocity of water descending through a fishway waterway and obtaining the most favorable flow velocity for fish going upstream.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a spiral fishway according to the present invention has a straight channel portion which rises while proceeding substantially linearly, and whose outer and inner peripheral walls are curved.
And becomes higher curved channel portion while curvilinearly advances are continuous alternately have been constructed so that the planar shape becomes substantially elliptic with water flowing in from the fishway outlet is curved channel
In the channel part, it is accelerated with centrifugal force,
Indicates that the acceleration slowed down and the flow velocity was once settled down.
Sign .

It is preferable that the straight channel portion and the curved channel portion are constructed by fishway blocks precast by concrete, respectively, and that the straight channel portion and the curved channel portion are connected.

The straight channel section and the curved channel section may be constructed by connecting one fishway block, or may be constructed by connecting two or more fishway blocks. In particular, it is preferable that the length of the straight channel portion can be changed by changing the number of fishway blocks. The fishway block can be connected in steps,
It can be connected in a continuous slope. The connecting means is not particularly limited.

[0008] The fishway block may be one that forms only the fishway channel (single channel fishway) or one that forms a fishway channel and a priming channel by a partition wall (priming fishway). In the case of a single channel type, it is preferable to separately construct a priming channel.

[0009] It is preferable to provide a partition in the fishway waterway of the fishway block to alleviate the water flow to create a resting place for the fish and to secure an appropriate overflow depth and shape for the fish. The bulkheads can be provided in the middle or at the ends of the individual fishway blocks. In addition, it is preferable to form a cutout in a part of the upper edge of the partition wall so that fish can select a level to get over. In particular, the cutouts make it easier for large fish to get over.

[0010] Part or all of the straight channel portion and the curved channel portion may be constructed of cast-in-place concrete. Also in this case, there may be a stepped fishway and an inclined fishway. Further, it is preferable to provide the partition wall in a fishway waterway. In addition, there is a single channel type fishway and a priming type fishway. In the case of a single channel type, it is preferable to separately construct a priming channel.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2 when the bird's-eye view angle is changed, the spiral fishway 1 according to the present embodiment includes two front and rear straight channel portions 2 that rise while traveling substantially linearly, and a curved (here, in this case). The two curved channel portions 3 on the left and right, which rise while traveling in a semicircular arc shape, are alternately continuous,
Thus, it is constructed so that the planar shape is substantially elliptical.

Each of the straight channel section 2 and the curved channel section 3 is constructed of a fishway block which is precast and formed of concrete so as to embed a reinforcing bar. Specifically, the front straight channel section 2 has a four-stage configuration, and each stage is constructed by connecting two fishway blocks. The rear straight channel section 2 has a three-stage configuration,
Each stage is constructed by connecting two fishway blocks. Both curved channel portions 3 have a three-stage configuration, and each stage is constructed by connecting three fishway blocks. The five types of fishway blocks 4, 5, 6, 7, and 8 used are as follows.

As shown in FIG. 3, the fishway block 4 which constitutes a step other than the uppermost step of the straight channel section 2 has a bottom wall having a flat rectangular shape, a lower surface being a horizontal surface, and an upper surface being an inclined surface having a predetermined gradient. 11, a straight outer wall 12, a partition wall 13, and an inner wall 14, which are erected on the bottom wall 11, and the upper end is open. The outer peripheral wall 12 and the inner peripheral wall 14 are formed higher than the partition wall 13 in order to increase the height difference of the fishway. A fishway waterway 15 is provided between the outer peripheral wall 12 and the partition wall 13,
A priming water channel 16 is formed between the partition wall 13 and the inner peripheral wall 14, respectively. On the bottom wall 11 in the middle of the fishway waterway 15, a partition wall 17 for relaxing the water flow and creating a resting place for fish is erected, and both sides of the partition wall 17 are outer peripheral walls 12.
And the partition wall 13 to reinforce the fishway block 4. The upper edge of the partition 17 has a high central portion, a notch 18 is formed on the outer peripheral side, and a deeper notch 1 is formed on the inner peripheral side.
8 are formed.

As shown in FIG. 4, the fishway block 5 constituting the uppermost stage of the straight channel portion 2 has the outer peripheral wall 12 and the inner peripheral wall 14 lowered to the same height as the partition wall 13, and Except that a recess 19 is formed on the downstream side of the upper end surfaces of the 12, 13, and 14, the fishway block 4
It has the same configuration as.

As shown in FIG. 5, the fishway block 6 that constitutes a section other than the uppermost section of the curved channel section 3 has a bottom wall 11.
Has a plane circular arc shape, the outer peripheral wall 12, the partition wall 13 and the inner peripheral wall 14 are curved, and the partition wall 13 is raised to the same height as the outer peripheral wall 12 and the inner peripheral wall 14. The structure is the same as that of the fishway block 4 except that light-emitting windows 20 extend through these 12, 13, and 14. In addition, when there is no light in the fishway waterway, fish do not go up, and when there is an appropriate light in the fishway waterway, the upstream rate becomes highest. Therefore, in the present embodiment, the lighting window 20 is provided only in the fishway block 6, but a window may be provided only in the fishway block 4 of the straight channel section 2, or the windows may be provided in both fishway blocks 4, 6. It may be provided.

The fishway block 7 constituting the uppermost stage of the curved channel section 3 has the same structure as that of FIG. 6 except that the outer peripheral wall 12 and the inner peripheral wall 14 are lowered to the same height as the partition wall 13. It has the same configuration as the fishway block 6.

As shown in FIGS. 1 and 2, the fishway block 8 connected to the uppermost fishway block 5 does not have a recess formed in the upper end surfaces of the outer peripheral wall 12, the partition wall 13, and the inner peripheral wall 14. Except for this point, the configuration is the same as that of the fishway block 5.

The fishway blocks 4 to 8 are connected stepwise when viewed from the outside, but the upper surface of the bottom wall 11 is connected so as to be continuously inclined. The connecting means is not limited as described above, but here, an anchor nut embedded in the fishway blocks 4 to 8, a bolt screwed to the anchor nut, and a connecting fitting connected between the fishway blocks by the bolt. (Not shown).

The end face of the fishway channel 15 of the first fishway block 4 of the first stage is open to the fishway entrance 15in, and the end face of the priming waterway 16 is opened to the downstream side as a priming outlet 16out. On the other hand, the end of the fishway waterway 15 of the fishway block 8 at the top is a fishway exit 15out,
The end surface of the priming water channel 16 is opened to the upstream side as a priming water inlet 16in.

In FIGS. 1 and 2, the spacer 21 shown with a lattice pattern in the first row is used to gradually increase the height of the fishway blocks 4 and 6 from the first row to the second row. However, no fishway channel has been formed.
The spacer 21 is constructed of cast-in-place concrete, but may be constructed of a block precast formed of concrete.

According to the spiral fishway 1 of the present embodiment, the following effects can be obtained. (1) The water that has flowed into the fishway channel 15 from the fishway exit 15out at the top is accelerated with the centrifugal force in the curved channel section 3, but the acceleration is reduced by the amount without the centrifugal force in the straight channel section 2. Once the flow rate calms down. Moreover,
The fishway waterway 15 is provided with a partition wall 17 for relaxing the water flow and creating a resting place for fish, so that the acceleration is further reduced. Therefore, the fishway entrance 1 at the bottom through the fishway waterway 15
The flow velocity of the water flowing out of 5 inches can be the most preferred flow velocity for the fish going upstream.

(2) Fishway blocks 4 to 8 in which the straight channel section 2 and the curved channel section 3 are precast.
It is possible to omit the on-site rebar arrangement process, formwork process, concrete placing process, etc.
Can be constructed in a short time with a small number of processes.

(3) Since the straight channel section 2 and the curved channel section 3 are constructed by connecting two or more fishway blocks 4 to 7, the individual fishway blocks 4 to 7 are reduced in size and weight, and are transported and handled. Is easy.

(4) The length of the straight channel section 2 can be easily changed by changing the number of fishway blocks 4 and 5 from two to one or three or more, and thus the flow rate of water can be reduced. Can be adjusted.

(5) The water that has flowed into the priming water channel 16 from the uppermost priming water inlet 16in is accelerated more strongly than the fishway water channel 15 by the amount that there is no partition in the priming water channel 16, so that it flows out from the lowermost priming water outlet 16out. The flow velocity of the generated water increases. This water current attracts fish and facilitates fish to find the fishway entrance 15in. Since the fishway blocks 4 to 8 are provided with the priming waterway 16, there is no need to separately construct a priming waterway.

(6) The upper edge of the partition wall 17 has a high center portion, a cutout portion 18 is formed on the outer peripheral side, and a deeper cutout portion 18 is formed on the inner peripheral side. Since there are three types, fish can select the level and get over it. In particular, the notch 18 makes it easy for a large fish to get over.

The present invention is not limited to the above embodiments, and may be embodied by appropriately changing the shape and configuration of each part without departing from the spirit of the present invention. (1) Each stage of the curved channel section 3 is constituted by one fishway block. (2) To provide a pattern (for example, a concavo-convex pattern imitating natural stone) on the inner surface or the outer surface of the fishway blocks 4 to 8 to reduce the artificial feeling and harmonize with the surrounding landscape. In particular, in the case where an uneven pattern is provided on the inner surface, algae and the like are easily attached, and the habitat environment is improved.

[0028]

As described in detail above, according to the spiral fishway according to the first aspect of the present invention, the flow velocity of the water descending down the fishway waterway is reduced to obtain the most preferable preferred flow velocity for the fish going upstream. Can be.

In addition to the above effects, according to the spiral fishway according to the second aspect of the present invention, the length of the straight channel portion can be easily changed while the number of steps can be reduced in a short period of time. Thus, the flow rate of water can be adjusted.

Further, according to the spiral fishway according to the third aspect of the invention, the configuration of the fishway block is simplified.

According to the spiral fishway according to the fourth aspect of the present invention, there is no need to separately construct a priming waterway.

According to the spiral fishway according to the fifth aspect of the present invention, the partition walls alleviate the water flow in the fishway channel and create a resting place for the fish, so that the fish can easily go up.

Further, according to the spiral fishway according to the sixth aspect of the present invention, fish can get over by selecting the level of the partition wall, and particularly, the cutout portion makes it easy for large fish to get over.

According to the spiral fishway according to the seventh aspect of the present invention, the degree of freedom in design and construction is increased.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a spiral fishway according to an embodiment of the present invention.

FIG. 2 is a perspective view of the spiral fishway viewed from a different bird's-eye view angle.

FIG. 3 is a perspective view of a fishway block that constitutes a section other than the top of the straight channel section of the spiral fishway.

FIG. 4 is a perspective view of a fishway block constituting the uppermost stage of the straight channel portion of the spiral fishway.

FIG. 5 is a perspective view of a fishway block that constitutes a section other than the top of the curved channel section of the spiral fishway.

FIG. 6 is a perspective view of a fishway block constituting the uppermost stage of the curved channel section of the spiral fishway.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spiral fishway 2 Straight channel section 3 Curved channel section 4 Fishway block 5 Fishway block 6 Fishway block 7 Fishway block 8 Fishway block 11 Bottom wall 12 Outer peripheral wall 13 Partition wall 14 Inner peripheral wall 15 Fishway waterway 15in Fishway entrance 15out Fishway exit 16 Waterway 16in Priming inlet 16out Priming outlet 17 Partition wall 18 Notch

Continuation of the front page (56) References JP-A-8-3972 (JP, A) JP-A-6-43030 (JP, U) JP-A-6-46035 (JP, U) (58) Fields investigated (Int) .Cl. ⁷ , DB name) E02B 8/08

Claims (7)

(57) [Claims] 1. A straight channel portion that rises while proceeding substantially linearly, and a curved channel portion that rises while proceeding in a curved manner with curved outer and inner peripheral walls are alternately continuous, and thus have a substantially planar shape. Built to be oval ,
Water flowing in from the fishway outlet is centrifuged in the curved channel
Accelerated with force, slowed down in the straight channel section
Spiral fishway , characterized by having the flow velocity settle down once . 2. The fish channel block of the straight channel portion and the fish channel block of the curved channel portion, wherein each of the straight channel portion and the curved channel portion is constructed by a fish channel block precast by concrete. The spiral fishway described. 3. The spiral fishway according to claim 2, wherein the fishway block constitutes only a fishway waterway. 4. The spiral fishway according to claim 2, wherein the fishway block constitutes a fishway waterway and a priming waterway by a partition wall. 5. The fishway waterway of the fishway block is provided with a partition wall for alleviating a water flow to create a resting place for fish and for ensuring an appropriate overflow depth and shape for the fish. The spiral fishway according to 3 or 4. 6. The spiral fishway according to claim 5, wherein a cutout is formed in a part of an upper edge of the partition. 7. The spiral fishway according to claim 1, wherein a part or all of each of the straight channel portion and the curved channel portion is constructed of cast-in-place concrete.