JPH08120655A - Construction of fishway extending all over cross section - Google Patents

Abstract

PURPOSE: To make running water concentrate to a waterway when the amount of running water is low and to make water run at different speeds in various areas arranged in the transverse direction when the amount of running water is high by a method wherein a gentle slope is formed, transversing a river, and blocks in different thickness are laid in combination to the slope. CONSTITUTION: First blocks 2, each in rectangular board-like shape, are laid in a straight line at the center on the surface of a gentale slope 1 crossing a river, and thereby a waterway 7 is constructed. Then, the first blocks 2 and second blocks 3, each provided with a chevroned projection 5 extending in the breadthwise direction on its surface, are arranged in combinations, extending from the position of the waterway 7 toward both banks so that the chevroned projections 5 can be arranged symmetrically on both sides of the waterway 7 to form a trapezoid, being headed toward the downstream side. By laying the blocks in several rows of such arrangement, running water can be concentrated to the waterway 7 when the amount of running water is low while resistance is given to water running the outside of the waterway 7 when the amount is high, and thereby areas where water runs at different speeds are distributed in the direction transversing the gentle slope 1 so that fishes can select a route for going upstream in accordance with their capacities of swimming.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a full-section fishway which does not hinder the migration of fish downstream of a river crossing structure such as a weir or a drop structure.

[0002]

2. Description of the Related Art Various techniques have been proposed in order to secure a fishway for fish run-up in a river region where a river crossing structure such as a weir or a drop structure is provided. In this fishway construction technology, for example, as shown in Japanese Patent Publication No. 5-26888, a waterway-like fishway (a waterway-like structure with a width of several 10 cm to several meters) is attached to a part of the river width. And, there is one that has a fishway over the entire width of the river. As the latter so-called full-section fishway, for example, the stairway type shown in FIG. 15 and the curved slope type with coarse stone shown in FIG. 16 are well known.

[0003]

[Problems to be Solved by the Invention] However, when a hydrographic fishway is constructed in a part of the river width, it is difficult for fish to find the entrance of the fishway, the fishway width is too narrow for the river width, and the riverbed falls, depending on the position. May cause the fishway entrance to float, usually because there is no fishway flow regulator, sometimes too much and sometimes too little, limiting the fish's run-up period. There are problems such as. In the case of the above technique, the height of the gate provided in the fishway is adjusted to keep the depth of water flowing over the gate constant, so that the above-mentioned problems can be solved to some extent. , Other problems ~ can not be solved.

On the other hand, the above-mentioned items (1) to (3) can be solved by using a fishway having a full section. However, in the case of the staircase type, since the entire cross section becomes almost the same in the longitudinal direction, the influence on the performance of the fishway when the flow rate changes is large, and the above problems cannot be essentially solved. In addition, in the case of the curved slope type with coarse stone, by adopting a curved surface, it is possible to concentrate the running water in the center of the river and flexibly respond to changes in the flow rate,
Since the effect of reducing the flow velocity in the fishway depends on the arrangement of coarse stones, not only is design very difficult, but also construction is time-consuming.

The object of the present invention is to secure a water depth necessary for river run-up and river down of fishes and a reflex of a reduced flow velocity at a predetermined position in the width direction of the river when the amount of water flow is small. When there is a lot of water, it is possible to create different flow velocity regions between the above-mentioned reflexes and the riverbank so that fishes can select the upstream route according to their swimming ability, and it is possible to reliably design and construct the upstream route of such various velocity regions. At the same time, it is to provide a method of constructing a fishway that can be relatively easily constructed.

[0006]

The present invention is characterized in that the following constitution is adopted to achieve the above object.
That is, first, a gentle slope having a required width is formed from the upstream side to the downstream side of the required position of the river. When a river crossing structure such as a weir or a drop structure is installed, a gently sloping surface is formed, for example, over the entire cross section on the downstream side. In addition, when newly installing these river crossing structures, the structures themselves should be provided with gently sloping surfaces. Blocks are laid on the gently sloping surface. These blocks are composed of a plurality of types of blocks, and are constituted by those having an uneven surface on the upper surface, those having an uneven surface or a flat surface, those having different thicknesses, and the like. And the present invention, by arranging these blocks in combination, when the flow rate is small, the flowing water is concentrated in a part of the transverse direction of the gently sloping surface to form a continuous reed portion from upstream to downstream, In addition, when the flow rate is high, resistance is given to the running water outside the muscular portion so that different flow velocity regions are distributed in the transverse direction of the gentle slope.

[0007] The reflex portion is formed by a continuous flat surface of the upper surface of the block in a substantially central portion in the transverse direction of the gently sloping surface, and the protrusion of the block is slanted in the downstream direction from the shore side toward the reflex portion. By arranging the above, it is preferable to form a guide path for the water flow to the reed muscle portion and the different flow velocity region described above. In this case, two types of blocks are used: a first block having a flat upper surface and a second block having a projection extending in the left-right width direction on the upper surface. The first block is continuously laid from the upstream side to the downstream side at a predetermined position in the transverse direction of the gently sloped surface, for example, in the central portion to form the reflex portion. In accordance with this, by laying the first block and the second block so that the projections of the second block are slightly shifted in the downstream direction from the shore side to the above-mentioned reflexes portion, the gently sloping surface is provided with the above. The different flow velocity areas and the guideway to the Mio muscle part are formed.

Further, the block has a first block whose upper surface forms a rough surface due to regular or irregular unevenness, and a projection extending in the left-right width direction on a part of the upper surface, and on another portion of the upper surface. Two types, that is, the upper surface of the first block and the second block having the same rough surface may be used.
The protrusions on the upper surface of the block may have different heights.

[0009]

In the present invention, the overflow water from the river crossing structure is
It flows over a large number of blocks laid across the entire width of the gently sloping surface. The block is made of a material having a different thickness, or a surface having an uneven surface or a flat surface, and these are arranged in a predetermined positional relationship. Therefore, when the flow rate is small, the flow described above is guided by the projecting portion on the surface of the block and concentrates on the reflex portion continuous from the upstream of the gently inclined surface to the downstream. When the running water is guided to the block protruding part, the flow velocity is reduced due to the collision with the protruding part. Secure and flow. As the flow rate increases, the width of the flow with the main basin of the reeds expands outward, creating a part that flows over the protruding part of the block, which gradually spreads to the shore. Although the flow velocity in the limbs increases more than in the above case, the velocities in the crossing over the protruding part of the block are different in the direction of the different slope crossing direction, that is, the velocities continuously from the limbs to the shore. Result in a declining basin. For this reason, the fish goes up the gently sloping surface by selecting a desired flow velocity region according to the swimming ability according to the fish species and the body length.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to an illustrated embodiment. FIG. 1 is an explanatory view of a fishway constructed by applying the present invention. Reference numeral 1 in the figure is a gently sloping surface formed on the downstream side of the weir, and is set to an appropriate slope depending on the situation of the construction site, the type of fish going up, and the like. Usually, about 1/5 to 1/25 is desirable.

First and second blocks for fish path formation are laid on the entire surface of the gently inclined surface 1 in a predetermined positional relationship. As shown in FIG. 2, the first block 2 has a rectangular plate shape with a required thickness. As shown in FIG. 3, the second block 3 is formed by forming a ridge 5 on the upper surface of a block body 4 having the same size as the first block 2, and the ridge 5 is formed in a mountain-shaped cross section. The block body 4 has a depth width from one end of the block body 4 in the front-rear direction to a position approximately half of the top surface of the block body in the front-rear direction and a front width corresponding to the left-right width of the block body 4. In the figure, reference numeral 6 indicates a flat surface of the upper surface of the block body of the second block 3.

FIG. 1 shows how the blocks are arranged on the gently inclined surface 1.
Will be described with reference to. In FIG. 1, the blocks that are continuously laid in the length direction of the gently inclined surface 1 are sequentially arranged from the most upstream side.
Steps, 2 steps, 3 steps, ... Steps are displayed, and blocks that are continuously laid in the transverse direction of the gently sloping surface 1 are sequentially arranged from the left bank side in the figure to 1
Columns, 2 columns, 3 columns, ... Columns are displayed. In the five rows located in the central portion in the transverse direction of the gently inclined surface 1, the first blocks 2 are laid continuously in a straight line in all stages from the upstream to the downstream to form the reed portion 7. The first block 2 and the second block 3 are combined on the gently sloping surface in the transverse direction from the Mio-suji part 7 to the left and right riverbanks, and the second block 3
The ridges 5 are arranged so as to be slightly shifted in the downstream direction from the shore side toward the lioness portion 7. This arrangement is repeated the required number of times from the most upstream stage to the third stage downstream. Instead of repeating the same sequence as in the present embodiment, different sequences can be made downstream. In particular, since the flow velocity becomes faster downstream in the muscular portion 7, the second block 3 adjacent to the muscular portion 7 is connected to the first block 2
Alternatively, it is preferable to use a short ridge 5 having a short length so that the width of the reflex part 7 is increased in the downstream region.

Taking the blocks from the first stage to the third stage as an example, first, the first to fourth columns and the sixth to ninth columns located in the left-right direction of the third stage block of the reed portion (5 columns). The same first block 2 is continuously laid in the same. Mio area (5 rows)
The second block 3 is arranged in the second row 4 row and the second row 6 row adjacent to the second row block so that the ridge 5 is located on the downstream side. The second block 3 is arranged in the second row and the third row and the second row and the seventh row that are adjacent to the outside so that the ridge 5 is located on the upstream side. Further, the first blocks 2 are arranged in the first and second rows of the second stage and the eighth and ninth rows of the second stage.

In addition, the first block 2 is provided in each of two columns adjacent to the left and right direction of the first stage block of the reed portion (5 columns), the first stage 3, 4th column and the first stage 6, 7th column. Is provided. The second blocks 3 are arranged in the first row, second row, and the first row, eighth row, with the ridges 5 thereof located on the downstream side. Furthermore, 1
In the first row and the ninth row, the second blocks 3 are arranged with the ridges 5 thereof located on the upstream side.

Since the depth width of the ridge 5 of the second block 3 and the depth width of the flat surface 6 are substantially the same, the first and second blocks 2 and 3 are formed from the first stage to the third stage. By arranging the above as described above, the ridges are continuous in a state in which the ridges are gradually shifted in the downstream direction from the riverbank side toward the muscular portion 7 in a symmetrical manner with respect to the central muscular portion 7. Further, since the ridges 5 of the adjacent second blocks 3 have a mountain-shaped cross-sectional shape, the edges are separated from each other, and a slight gap is generated. A part of the running water having a flow rate that does not get over the ridge 5 also flows through the gap to the downstream block.

In the present embodiment, the running water guided by the ridges which are continuous in a stepwise manner on the slope is guided to the central reed portion 7 in the transverse direction of the slope, and even when the flow rate is small, the fish run up to this part. Securing the fishway of the required water depth. In addition, due to the running water that has passed over the ridge 5, various upstream passages of fish having different flow velocity regions are formed downstream of the ridge. Also, when arranging the blocks, if the rows along the riverbank are arranged so that the riverbed is higher than the central row or single or multiple rows, or if it is arranged so as to incline toward the central part, running water to the central part It is effective not only for guiding but also for creating various flow velocity regions.

In carrying out the present invention, blocks having shapes or types different from those of the blocks used in the above-described embodiments may be used. FIG. 4 is an explanatory diagram of a fishway constructed using the block according to the example.
In this embodiment, the first block 2 shown in FIG. 2, the second block 13 shown in FIG. 5, and the third block 8 (see FIG. 4) whose depth width is half that of the first block 2 are used. The second block 13 is formed to be thicker than the first block 2, and a portion 15 protruding upward by the thickness thereof has the same function as the ridge 5 of the second block 3 of the above-described embodiment. . Further, since the depth width of the projecting portion 15 is the same as that of the first block 2, these blocks 2, 13 and 8 are arranged in a staggered manner in a plane and the third block 8 which is half the depth width is Used in place.

FIG. 6 is an explanatory diagram of a fishway constructed using blocks according to another example. In this embodiment, the second block 23 has a ridge 25 at the center of the upper surface of the main body in the front-rear direction.
Are projected and have flat surfaces 26 on the front and back of the upper surface (see FIG. 7).
reference). The first block 22 and the second block 23, each of which has a flat upper surface, are made of two types having different left and right widths. Then, in the present embodiment, these blocks 22 and 23 are provided with ridges 25 as shown in FIG.
Are arranged so as to be spaced apart from each other in the flowing direction of the flowing water and partially overlap in the transverse direction so that the flowing water is finally guided and concentrated in the reflex muscle portion 27.

8 and 9 show further blocks, respectively, used in the method of the present invention. FIG. 8 shows a second block 33 having a protrusion and a first block 32 having no protrusion. The entire upper surface of the first block 32 and the protrusion 35 of the second block 33 are provided in a protruding manner. A large number of grooves 36 that are continuous in the left-right width direction are formed in the upper surface portion that is not formed. Due to the large number of grooves 36 that are orthogonal to the direction of water flow when the blocks 32, 33 are laid, both blocks 32, 33 further reduce the velocity of the water flowing over them. Such a groove may be a rough surface having regular or irregular unevenness as long as it can contribute to the reduction of the velocity of flowing water. The block 43 of FIG. 9 is constructed by embedding a plurality of natural stones 44 in appropriate positions on the upper surface so as to be lined up in the front width direction, so that the protruding natural stones 44 exhibit the same action as that of the ridge. is there. By using this block 43, the fishway constructed by the method of the present invention has an aspect in harmony with the surrounding nature.

The reed portion does not have to be formed in the central portion in the transverse direction of the gently sloped surface, and may be provided at a position closer to one of the shores depending on the situation of the site or the like. It is also possible to prepare several types having different heights and arrange these at appropriate positions on the slope.

Experimental Example In order to confirm the function of the whole-section fishway according to the method of the present invention, a model experiment was conducted in the following manner (see FIGS. 10 to 12). Open channel: Width 50 cm Gradient slope head: Gradient 1/10, drop 9.2 cm Laying block: Arrangement of mortar model block blocks with the shape shown in Fig. 11 and both front width and depth width of 5.0 cm: Slope to which the method of the present invention is applied The thickness H of the model block is 1.7 cm, 2.5 cm,
Three types of blocks of 3.3 cm were combined and coated as shown in FIG. The smallest thickness (H = 1.7 cm) is continuously arranged in the central portion in the transverse direction from the upstream to the downstream, and three types of blocks are arranged on the left and right of the three types of blocks so that the water flow is concentrated in the central portion. It is arranged as follows. Comparative Slopes Only the above model blocks having a thickness H of 1.7 cm were coated. Creation of water flow: Install a rectification device upstream of the gentle slope heading,
Water flow was generated by two submersible pumps (see FIG. 10). When one submersible pump is operated, the flow rate is small, and when two submersible pumps are operated, the flow rate is large.

The following results were obtained when the running water conditions on the slopes were measured. The water depth was visually observed using a gauge of φ1 mm, and the flow velocity was measured by a propeller type velocity meter. First, when the flow rate was small, the water depth was almost uniform on the slope of 2 to 4 mm. Therefore, it may not be possible to secure sufficient water depth for fish to run upstream when the flow is small. On the other hand, on the slope, the flow was concentrated on the slope in the central portion in the transverse direction, and a continuous crease portion having a water depth of 10 to 18 mm was formed from the upstream portion to the downstream portion (see FIG. 13). For this reason, it is considered that the number of fish species that can go up the head drop significantly increases in the local river even when the discharge is small, compared to the flat gently sloping head drop. In addition, near the two banks on the slope of the drop work, there was a part where a very weak circulation flow was formed with shallow water depth connected to the Mio. This part serves as a route for small fish with weak swimming ability and a resting place during the course.

Next, when the flow rate is large, on the slope of, the flow velocity is 60 cm /
Although the maximum value was about s, it was almost uniform on the entire slope, and the minimum value was 40 cm / s. on the other hand,
On the slope of No. 2, the water flow collected in the central portion had a higher flow velocity than that of the slope of No. The flow velocity of 80 cm / s or more was shown on the downstream side of the central slope, but the flow velocity drastically decreased as it deviated from the center, and the minimum flow velocity on the slope was 40 mm / s or more. The center area was about 1/3. vice versa,
On the shore side, there was a part where the flow velocity was slower than the slope of.
Therefore, it is considered that a fish running up this slope in the local river can run up the slow stream part on the shore side according to its own swimming power, avoiding the fast flow part in the central part.
Furthermore, the fast flow plays a role of priming fish and at the same time, it is possible to protect the pond in the immediate downstream of the drop construction to prevent sedimentation on the river bed at the downstream end of the slope. Since the water overflowed all blocks with a considerable thickness, the fish could swim in the stream without jumping over the overhangs using blocks of H = 2.5.3.3 cm. You can

[0024]

As described above, according to the present invention, due to the arrangement of blocks laid on the gently sloping surface, a part of the gentle sloping surface in the transverse direction is always provided from the upstream side to the downstream side regardless of the change in the water flow rate. Since the continuous muscular portion is formed, it is possible to secure the water depth and flow velocity paths required for fish run-up regardless of the time. Further, according to the present invention, different flow velocity regions are distributed in the transverse direction of the gently sloping surface by the projections on the surface of the block that guide the flowing water to the reflex muscles. When the upper path can be selected and the flow rate is relatively high, the running water flows over most of the projections, so that the fish can easily go up without jumping on the slope. Further, according to the present invention, since the blocks having a fixed shape are simply laid in a predetermined arrangement, it is possible to reliably and easily design and construct the upstream path of various flow velocity regions.
Furthermore, according to the present invention, in the most downstream portion of the slope, sedimentation of sediment in this portion is prevented by the relatively fast flow concentrated in the reed portion, so that the action as a fishway is not hindered, In some cases, a pond can be formed in this part, which is a favorable environment for fish habitat.

[Brief description of drawings]

FIG. 1 is an external view of a fishway with a cross section constructed by applying a method according to an embodiment of the present invention.

2 is a perspective view of a first block used in the fishway construction of FIG. 1. FIG.

FIG. 3 is a perspective view of a second block used in the fishway construction of FIG. 1.

FIG. 4 is an external explanatory view of a fishway with a full cross section constructed by applying a method according to another embodiment of the present invention.

5 is a perspective view of a second block used in the fishway construction of FIG.

FIG. 6 is an external explanatory view of a fishway with a full cross section constructed by applying a method according to still another embodiment of the present invention.

7 is a perspective view of a second block used in the embodiment of FIG.

FIG. 8 is a perspective view of another block used in the present invention.

FIG. 9 is a perspective view of yet another block used in the present invention.

FIG. 10 is a structural cross-sectional view of an experimental example for confirming the function of the present invention.

11 is a perspective view of a model block used in the experiment of FIG.

FIG. 12 is a plan view showing three types of model blocks of FIG. 11 having different thicknesses prepared in the experiment of FIG. 10 and arranged on a slope.

FIG. 13 shows an arrangement state of the model blocks in FIG.
The figure which shows the water depth distribution of flowing water with a small flow rate.

FIG. 14 shows an arrangement state of the model blocks in FIG.
The figure which shows the flow velocity distribution of flowing water with a large flow volume.

FIG. 15 is an external view of a conventional staircase-type full-section fishway.

FIG. 16 is an external view of a conventional curved slope full-section fishway with coarse stones.

[Explanation of reference numerals] 1 ... gently sloping surface 2, 22, 32 ... First block 3, 13, 23, 33, 43 ... ・ Second block 5,25 ・ ・ ・ ・ ・ ・ ・ ・ Ridge 6,26 ・ ・ ・ ・ ・ ・ ・ ・ Flat surface 7 ・ ・.....................

Claims (5)

[Claims] 1. A gently sloping surface having a required width is formed from an upstream side to a downstream side of a required position of a river, and blocks are laid on the gently sloping surface. These blocks are combinations of blocks having different thicknesses or When the flow rate is small, the combination of the protrusions and the flat surface provided on the upper surface concentrates the running water in a part of the transverse direction of the gently sloped surface to form a continuous crease portion from upstream to downstream, and When there is a lot of water, it is arranged so as to give resistance to the running water on the outside of the muscular portion so that different flow velocity regions are distributed in the transverse direction of the gently sloping surface. 2. A portion in which running water is concentrated when the flow rate is small is provided at a substantially central portion in the transverse direction of the gently sloped surface, and a block is arranged in this portion so that a flat surface is continuous from upstream to downstream. On both the left and right sides of this block, a block having a thicker thickness than this or a block having the above-mentioned projecting portion is used to guide the flowing water to the above-mentioned concentrated portion when the projecting thickness or the projecting portion is small, while The method for constructing an all-section fishway according to claim 1, wherein the fishway is constructed so as to provide resistance to the flowing water so as to distribute different flow velocity regions in the transverse direction when the flow amount is large. 3. The block comprises two types of blocks, a first block having a flat upper surface and a second block having a projection extending in the left-right width direction on the upper surface. The blocks are continuously laid from the upstream side to the downstream side in the central portion in the transverse direction of the gently sloping surface, and the first block and the second block have the protrusions of the second block from the shore side in the transverse direction center. By laying so that it gradually shifts toward the downstream part,
The method for constructing a fishway of full cross section according to claim 2, wherein the different flow velocity regions and the concentrated guideway to the reed muscle portion are formed on the gently sloped surface. 4. The block has a first block whose upper surface forms a rough surface due to regular or irregular irregularities, and a projection extending in the left-right width direction on a part of the upper surface, and another portion of the upper surface. And a second block having a rough surface similar to the upper surface of the first block, and the first block is continuously arranged from upstream to downstream at a predetermined position in the transverse direction of the gently sloping surface. Laying it as the reed portion, and laying the first block and the second block such that the projections of the second block are slightly shifted in the downstream direction from the shore side toward the reed portion. The method for constructing a fishway according to claim 1, wherein the different flow velocity regions and the concentrated guide path to the reflex muscle portion are formed on the gently sloped surface. 5. The second block is composed of a plurality of types of blocks having different heights of the protrusions, and the protrusions having different heights are obliquely continuous in the downstream direction toward the reflex portion. A second block is laid, The method for constructing a fishway according to claim 3 or 4, wherein the second block is laid.