JP2002363956A - Fish ladder, kit, and method for assisting going-upstream and/or -downstream of aquatic organism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restore or conserve populations of migratory aquatic organisms by assisting the going-upstream and/or -downstream of the aquatic organisms. SOLUTION: This fish ladder which is installed in a fall part in the upstream/ downstream of a river transversal structure and provided with multiple buffer means 30 having first clearances allowing flowing water to pass therethrough, support means 10 and 20 supporting the multiple buffer means, and second clearances 35 partitioned by the buffer means and the support means, is used, the flowing state is adjusted via the first clearances, and a passage for passing the aquatic organisms is formed by the second clearances so as to assist the going-upstream and/or -downstream of the aquatic organisms.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for assisting aquatic organisms to go up and / or down a river, and to a fishway and a kit.

[0002]

2. Description of the Related Art Many aquatic organisms inhabiting rivers have "through migratory properties" that move between the sea and rivers in their life history. These migratory aquatic organisms cannot reproduce unless they have to travel between seas and rivers in their life history.

For example, ayu lays eggs in a freshwater area, hatched larvae flow down to a salty estuary or the sea, spend their larval stage in the estuary or the sea, grow into juvenile ayu, and then go up the river.
In addition, shrimps such as giant shrimp and pond shrimp and crabs such as mokusugani crawling in the sea after their floating larvae, transforming into juvenile shrimp and juvenile crab, and then go up the river.

However, at present, many rivers are provided with river crossing structures such as dams, weirs, erosion barriers, head works, etc., whereby the migration path of the aquatic organisms is cut off. A population of migratory aquatic organisms is at risk of decline (decrease) or extinction.

[0004] In addition, among the aquatic organisms, there are species that are important as foods for fish and the like, and these are one of the organisms that constitute food webs in rivers and the sea. And extinctions are disrupting the balance of food webs and are having a major impact on river and sea ecosystems.

[0005] Here, attempts have been made to install fishways in river crossing structures. However, conventional fishways are intended for swimming fish having strong swimming and jumping powers, and are not suitable for crustaceans and benthic fish. It is not suitable for ascending and / or descending by walking. In addition, the effect of promoting sufficient ascent and / or descent for swimming fish has not been obtained. In addition, the conventional fishway requires a great deal of labor for production and installation, and its maintenance is also expensive. In addition, installation work and maintenance work sometimes led to the destruction of nature.

[0006] Accordingly, an object of the present invention is to provide a method for effectively and easily assisting the ascending and / or descending of aquatic organisms, and a fishway and a kit suitable for the method, whereby a migratory aquatic organism is provided. Restoration or maintenance of populations of organisms, and restoration or maintenance of ecosystems in seas and rivers.

[0007]

Means for Solving the Problems As a result of extensive observations, the present inventors have obtained the following findings regarding the ecology of aquatic organisms going upstream and / or descending.

[0008] Aquatic organisms (swimming fish such as sweetfish, benthic fish such as Yoshinobori, and crustaceans) have a property (positive running property) that tends to go upstream against the flowing water.

[0009] Swimming fish such as sweetfish fly up and / or down in places where there is a certain flow velocity and water depth. on the other hand,
Crustaceans and benthic fish go up and / or descend by crawling along the extremely shallow and gentle flow at the shore (when there is an overflow), or at the bottom of the river at the core.

[0010] When the upstream portion has a predetermined inclination angle with respect to the horizontal plane, the upstream and / or downward movement of aquatic organisms is facilitated.

The times at which aquatic organisms run up and / or descend are seasonally limited.

[0012] Swimming fish, such as sweetfish, rest at places where the flow is weakened and there is a certain depth of water.

The crustaceans approach the weir flow section while crawling along the water until immediately before going up. In addition, the crustacean finds a point where a critical flow is approaching from a fast-flowing area to a slow-flowing area, and enters the water from the water's edge.

The present invention, in view of the ecology of aquatic organisms, provides an optimal fishway for ascent and descent by swimming of swimming fish, and ascending and descent by crawling of crustaceans and benthic fish. It is.

[0015] That is, the fishway according to the present invention is installed at the head of the river crossing structure at the upstream and downstream, and has at least one part for relaxing the flow and a part for relatively promoting the flow. Features.

The river crossing structure corresponds to a dam, a weir, a sabo, a head work and the like provided in the river.

Examples of the aquatic organisms include swimming fishes such as sweetfish and kawamutu, crustaceans such as shrimp such as Yamatonuma shrimp, southern shrimp and mizorenuma shrimp, and crabs such as mokusugani.
In addition, benthic fish such as Yoshinobori, eel, gokurakuhaze, etc. are applicable.

A fishway according to the present invention refers to any device that allows or assists aquatic organisms to climb and / or descend crossing structures constructed in rivers. The fishway of the present invention may or may not be fixed at the installation location.

The portion that alleviates the flow is a portion where the flow is relatively gentle, and the portion that promotes the flow is that the flow rate and the flow velocity in the downstream direction of the flow in the fishway distribution are relatively small. It is a high part.

With this configuration, the distribution of the flow in the fishway is adjusted, and the ascending and / or descending of aquatic organisms is extremely effectively promoted.

In the above, aquatic organisms can stay at the portion where the flow is alleviated, and the aquatic organisms can go up and / or down by swimming or crawling at and / or in the vicinity of the portion that promotes the flow. is there.

[0022] In contrast to the conventional fishway in which swimming fishes are made to swim while jumping, the present invention adopts the above-described structure, whereby aquatic organisms can travel while temporarily staying as appropriate while swimming. Can be up and / or down.

Further, the fishway according to the present invention is installed at the head of the river crossing structure at the upper and lower part of the river, where the swimming fish swim and go up and / or down, and the swimming fish stay there. And

The fishway according to the present invention has a buffer member installed at the head of the river crossing structure on the upper and lower sides of the structure to adjust the flow state, and a support member for supporting the buffer member.

Examples of the cushioning member include those having pores (holes) so that flowing water can pass through the pores, and those having no pores.

This buffer means may be arranged detachably. By attaching or detaching some or all of the buffer means, it is possible to adjust the distribution of the stream in the fishway to be most suitable for aquatic organisms going up and / or down during the season.

A fishway according to the present invention is a fishway installed at a head drop on the upstream and downstream of a river crossing structure, and has a first gap through which flowing water can pass, and supports the buffering member. And a support member, wherein the buffer member adjusts a flow state through the first gap.

The first gap through which flowing water can pass is a hole or a gap having such a size as to allow flowing water to pass through a buffer member arranged as a buffer means. As the flowing water passes through the first gap, the momentum of the flow is absorbed and the flow velocity of the water flowing down the fish passage is temporarily reduced, so that the distribution of the flow in the fish passage is adjusted, and the upstream of the aquatic organisms and And / or the descent is promoted very effectively.

[0029] The fishway according to the present invention is a fishway installed at the head of the river crossing structure at the upstream and downstream of the structure, comprising a buffer member, a support member for supporting the buffer member, the buffer member and the support member. And the buffer member adjusts a flow state, and aquatic organisms can pass through the second gap.

[0030] The second gap is formed, for example, between a river bottom at a head and a head of a river crossing structure to which a fish passage is attached and a buffer member and / or a support member.
A hole or gap that forms a passage through which aquatic organisms can pass. The second gap forms a passage through which aquatic organisms can pass, so that upstream and / or descent is extremely effective not only for crustaceans and benthic fish crawling on the bottom of the river, but also for swimming swimming fish. Promoted.

The fishway according to the present invention is a fishway installed at the head of the river crossing structure at the upstream and downstream, and has a first gap through which flowing water can pass, and supports the buffering member. A support member, and a second gap defined by the buffer member and the support member, wherein the buffer member adjusts a flow state through the first gap, and Can pass through the second gap.

[0032] The second gap may be formed between the cushioning member and the support member.

[0033] The fish passage may include a plurality of the buffer members, and the plurality of buffer members may be provided at a predetermined interval and fixedly supported by the support member. Thus, by arranging the buffer members at regular intervals, it is possible to preferably form a flow distribution in the fishway. That is, a relatively gentle flow (remaining portion of the flow) near the upstream side of the buffer member is sequentially and regularly formed, and the second gaps through which aquatic organisms can pass are formed at regular intervals. Therefore, aquatic organisms can very easily crawl and / or swim from the second gap of the buffer means to the second gap of the next buffer means.

In particular, the buffer means is 400 mm or more and 550 m
m and fixedly supported by the support means, so that the aquatic organisms can go up and / or
Or a flow distribution suitable for descent is formed.

The fish passage includes a plurality of the buffer members, and the plurality of buffer members are disposed so as to gradually increase in distance from the upstream side to the downstream side, and are fixed and supported by the support member. Good.

Preferably, the cushioning member includes a filling member and a member capable of storing the filling member.

The member capable of storing the filling member is preferably a net-like member.

The mesh member has a large number of meshes, such as PE (polyethylene), PP (polypropylene),
Synthetic resins such as PVC (polyvinyl chloride), PET (polyethylene terephthalate), nylon, and fluororesin, natural resins, chemical fibers, natural fibers such as Manila hemp, and metals such as stainless steel and iron are preferably used. In particular,
Aquatic organisms (ayu, etc.) can be obtained by using a synthetic resin mesh member.
It is suitable without damaging the body.

The mesh member may be in the form of a sheet or a bag. In particular, it is simple and effective to use a net-like sheet member and bundle it in a state in which gravel is filled (included) to form a buffer member.

[0040] The support member may be composed of a pair of hollow rod-shaped members.

[0041] The pair of support members may be fixed by a beam member interposed therebetween. With a beam member interposed,
By fixing one end of the beam member to one support member and fixing the other end of the beam member to the other support member, it is possible to keep the distance, angle, and the like between the pair of support members constant.

[0042] The support member may be provided with fixing means for fixing both ends of the buffer member.

As the fixing means, a screw hole may be provided in the support member, and the buffer member may be fixed to the support member by tightening a screw. By releasing the fixing by the fixing means, the buffer member can be easily attached to and detached from the fishway.

As another example of the fixing means, an engaging portion is provided on one of the ends of the support member and the cushioning member, and an engaged portion is provided on the other, and the engaged portion is provided with an engaging portion. The buffer member may be configured to be fixed to the support member by engaging with the support member. For example, a protrusion may be provided on the support member, and both ends of the buffering portion may be respectively tied to the protrusion, or may be fixed by hooking, or a recess may be provided in the support member and the protrusion may be provided in the recess. Alternatively, both ends of the cushioning member may be hooked and fixed to the protrusions.

It is preferable that the fishway is installed at a head where a river bottom is inclined. At this time, it is preferable that the inclination is not more than 50 ° and not less than 10 ° in order to promote the advancing and / or descending of aquatic organisms.

The fishway may be removably installed at the head. By making it detachable, the fishway can be installed only when necessary.

The kit according to the present invention is a kit for a fishway to be installed at the head of a river crossing structure at the upstream and downstream,
A plurality of mesh members capable of storing the filling member, a pair of support members made of a hollow rod-like body, and a fixing member for fixing the mesh member to the support members, wherein the pair of support members are
It is characterized by comprising a receiving means for receiving the fixing member. Since it is in the form of a kit, it is easy to assemble and adjust the fixing position and number of the mesh members.

The method for assisting the ascending and / or descending of aquatic organisms according to the present invention uses a fishway provided with adjusting means for adjusting the state of the flow, wherein the adjusting means reduces the flow, A part that relatively promotes
And a portion that promotes the flow and / or the vicinity thereof forms a passage through which aquatic organisms can pass, thereby assisting the ascending and / or descending of aquatic organisms.

According to the method of the present invention for assisting the ascending and / or descending of aquatic organisms, a first gap through which flowing water can pass is formed to adjust the state of the flow, and to guide the flowing water downstream. Thus, a passage through which aquatic organisms can pass is formed, and the ascending and / or descending aquatic organisms are assisted.

According to the present invention, there is provided a method for assisting upstream and / or descending of aquatic organisms, comprising a buffer means, a support means for supporting the buffer means, and a second means defined by the buffer means and the support means. And a flow path adjusted by the buffer means, and a passage through which aquatic organisms can pass is formed by the second gap, thereby assisting the ascending and / or descending of aquatic organisms. Is what you do.

[0051] The method for assisting the ascending and / or descending of aquatic organisms according to the present invention comprises a buffer means having a first gap through which a flowing water can pass, which is installed at a head portion of a river crossing structure. Adjusting the state of flow through the first gap using a fishway having support means for supporting the buffer means and a second gap defined by the buffer means and the support means. The second gap forms a passage through which aquatic organisms can pass, and assists in ascending and / or descending of aquatic organisms.

With the above configuration, the flowing water passes through the first gap of the buffer means, whereby the flow force is absorbed and the flow velocity of the water flowing down the fish passage is temporarily reduced. Therefore, the distribution of the flow in the fishway is adjusted, and the ascent and / or descent of aquatic organisms is promoted very effectively. In addition, since the second gap forms a passage through which aquatic organisms can pass, not only crustaceans and benthic fish crawling and / or descending along the river bottom, but also swimming and / or descending by swimming. For swimming fish, the run-up and / or descent is very effectively promoted.

The method of the present invention is applied to any case of assisting the ascending and / or descending of aquatic organisms, mainly assisting the ascending, and mainly assisting the descending. .

By using the above-mentioned method, fishway or kit, it is easy to ascend and / or descend aquatic organisms. Therefore, it is possible to restore or maintain a population of aquatic organisms having migratory properties, Recovery or maintenance of ecosystems.

[0055]

Next, embodiments of the present invention will be described, but the present invention is not limited thereto.

(Fishway and Auxiliary Method for Ascending and / or Descenting Using the Way) FIG. 1 is a view showing a fishway according to the present embodiment. FIG. 2 is a partially enlarged view of FIG. FIG.
FIG. 3 is a view of FIG. 2 viewed from a direction B. FIG. 4 is a diagram illustrating a state in which the fishways of FIG. 1 are installed at the upper and lower heads of a river crossing structure.

In FIG. 1, the fishway 100 comprises a pair of support members 10, 20, a buffer member 30, and beam members 40a,
0b.

The support members 10 and 20 are each formed of a cylindrical body. The support member 10 and the support member 20 are fixed to each other by two beam members 40a and 40b in a state where both are arranged substantially in parallel.

The beam member 40a is composed of a full screw 41a whose entire peripheral surface is threaded, and a pipe 42a which has a substantially cylindrical shape and accommodates the full screw 41a in a hollow portion. Since the length of all the screws 41a is slightly longer than the length of the pipe 42a,
When all the screws 41a are accommodated in the pipe 42a,
Both ends of 1a protrude from both ends of pipe 42a. The support member 10 has a hole 11a through which the entire screw 41a is inserted,
The beam member 40a is fixed to the support member 10 by screwing the protrusion of the full screw 41a into the holes 11a and 12a and tightening the nut 44. Similarly, holes 21 a and 22 a through which the entire screw 41 a is inserted are formed in the support member 20.
The beam member 40a is fixed to the support member 20 by screwing the protrusion of the full screw 41a into 1a, 22a and tightening the nut 44. Similarly, the beam member 40b is also fixed to the support members 10 and 20. By fixing the beam members 40a, 40b, the distance between the support members 10, 20 can be improved.
The angle and the like can be kept in a fixed arrangement state.

The cushioning member 30 comprises a filling member 31 and a mesh member 32 filled with the filling member 31 and bundled. Filling member 3
The size of 1 is preferably in the range of 20 mm or more and 80 mm or less, particularly 30 mm or more and 50 m or less, from the viewpoint of forming a flow suitable for ascending and / or descending aquatic organisms.
m or less.

As shown in FIG. 1 and FIG.
Holes 13 and 23 for attaching the ends of the cushioning member 30 are provided at regular intervals in 0 and 20 (in the present embodiment, 9 and 9 respectively).
Pieces) are formed. Screws 15, 2 into these holes 13, 23
By screwing 5, the both ends of the buffer member 30 are fixed to the support members 10 and 20, respectively.

As shown in FIG. 3, when the cushioning member 30 is fixed to the support members 10 and 20, a gap 35 is formed between the buffer member 30 and the bottom of the river at the upstream and downstream of the river crossing structure to which the fishway 100 is attached. Is formed.

As shown in FIG. 4, the fishway 100 is a fishway 1
The upper part of 00 is near the top of the river crossing structure, and the lower part of the fishway is near the bottom of the river. Edge part). At the time of installation, one ends of ropes 51 and 52 are attached to both ends of the support member 10, and this rope 5
The other ends of the first and second 52 are tied to a desired place.

The water flowing from the upstream area flows down the fishway 100 to the downstream area while receiving a predetermined resistance. At this time, the buffer member 30 is filled with the filling member 31 by the mesh member 32.
, The flowing water passes through the mesh of the buffer member 30 and the momentum of the flow is absorbed, so that the fishway 1
The flow velocity of the water flowing down 00 is temporarily reduced, and the flow distribution is adjusted. In addition, a gap 35 is formed between the buffer member 30 and the bottom of the river crossing structure where the fishway is attached, and the aquatic organisms crawl or swim through the gap 35. Can pass through. Further, a relatively gentle flow (residence portion A) is formed near the upstream side of the buffer member 30. By arranging the buffer members 30 at regular intervals, the staying portions are regularly formed, and the gaps 35 through which aquatic organisms can pass are also formed at regular intervals.

As described above, according to the present invention, it is possible to effectively assist the ascent and / or descent of swimming fish such as ayu and the like, and to ascend by crawling of crustaceans and benthic fish. And / or descent can be effectively assisted.

The fishway 100 of the present invention has a structure suitable for being installed in a portion near the flow of a river. It is possible to provide a situation that is very suitable for ascending and / or descending organisms. In other words, by installing the fishway 100 at the edge of the stream, a slow-flowing portion can be formed at the edge of the fishway, so that not only can the aquatic organisms promote up and / or down in the fishway, but also the bottom Living creatures and crustaceans can climb and / or descend while crawling along slow sections of the stream. Furthermore, since the fishway 100 of the present invention uses the edge of the flow, it can be installed in a large river, and the installation and adjustment work is simple.

Since the cushioning member 3 is detachable,
A part of the plurality of buffer members 30 is removed, and the fishway 1 is most suitable for aquatic organisms going up and / or down during the season.
In addition to adjusting the flow in the buffer member 00, deterioration and consumption of the buffer member can be prevented.

In the above description, the beam members 40a, 4a
0b, the fishway provided with the ropes 51 and 52 has been described, but the fishway according to the present invention is also applied to a fishway which does not include all or a part thereof.
The present invention can be applied to a case where the number of holes 13 and 23, the number of screws 15 and 25, the arrangement interval between cushioning members 30, and the distance between supporting members 10 and 20 are different.

In the above, the pair of support members 1
Although the case where 0 and 20 are arranged in parallel has been described,
An angle may be formed between the support members 10 and 20 depending on the installation situation.

The filling member filled in the buffer member is not limited to gravel.

The fixing member for fixing the cushioning member 30 to the supporting members 10 and 20 is not limited to a screw, and various fixing means can be appropriately employed. That is, the support member 1
Protrusions may be provided at 0 and 20, and both ends of the cushioning member 30 may be fixed to the protrusions by fastening or hooking them. Alternatively, the support members 10 and 20 may be provided with recesses and provided in the recesses. Protrusions may be provided and both ends of the cushioning member 30 may be hooked and fixed to the protrusions.

The fishway 100 may be further fixed not only with the ropes 51 and 52 but also with a weight member such as an anchor.

(Kit) FIG. 5 is a diagram showing a kit for a fishway according to the present embodiment.

In FIG. 5, a kit 60 includes nine net-like members 61, a pair of cylindrical support members 62 and 63,
Two full screws 64, two pipes 65, four nuts 67, eighteen screws 68, two ropes 66,
Gravel 70.

The support members 62 and 63 have holes 69 into which the screws 68 are screwed as receiving means for receiving the screws 68.

The support members 62 and 63 are
Have holes 62a and 62b through which the holes are inserted. The support member 63 has holes 63a and 63b through which the entire screw 64 is inserted.

The method of assembling the kit 60 will be described below.

First, the entire screw 64 is accommodated in the hollow portion of the pipe 65, and both ends are screwed into the holes 62 a and 63 b and fixed by the nut 67. Next, after the net member 61 is spread and the gravel 70 is placed on the central portion, the bundle is bundled, the gravel is accommodated in the net member 61 to form a buffer member, and the screw 68 is tightened. Are fixed to the supporting members 62 and 63. In this way, a fishway as shown in FIG. 1 can be easily assembled. Then, the fishways assembled in the same manner as described above are installed at the upper and lower heads of the river crossing structure, and are appropriately fixed using the rope 66.

In the above description, the kit 60 including the full screw 64, the pipe 65 and the bolt 67 forming the beam member has been described, but the fishway kit according to the present invention does not include all or a part of these. It can also be applied to things. Further, a kit without the gravel 70 or the rope 66 or a kit having different numbers of the mesh member 61, the holes 69, and the screws 68 may be used.

The fixing member for fixing the mesh member 61 to the supporting members 62 and 63 is not limited to a screw, and various fixing means can be appropriately employed.

The support members 62 and 63 may be a single support member by connecting a plurality of short members, or may be configured so that the length can be adjusted by expanding and contracting in the length direction.

[0082]

EXAMPLES Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

(Preparation of Fishway) A fishway as shown in FIG.
It was produced as follows.

A single pipe having an outer diameter of 46 mm and a length of 5000 mm is used as the support members 10 and 20, all screw rods having an outer diameter of 10 mm are used as all screws 41a and 41b, and stainless steel pipes having an outer diameter of 16 mm are prepared as pipes 42a and 42b. did. These were assembled into a fishway having a width of 50 mm as shown in FIG. Next, gravel with an average particle size of about 30 mm was
A mesh sheet having a mesh of about 1 mm x 1 mm (900 mm
× 600 mm). The buffer member 30 was fixed to the support members 10 and 20 so that each interval was 480 mm.

(Outdoor Run-Up and / or Descent Experiment) The fishway 100 prepared as described above was fixed on the right bank of the Chofu weir of the Tama River (head drop 2 m, slope length 6 m, slope angle 18.5 °). Installed on the water's edge, two ropes 51,
52 (diameter 9 mm) and fixed as described above.

The experiment was conducted in May 2001 for 12 hours (7:45 am to 19:45 am). The experiment was performed in a restricted area of general public. FIG. 7 shows the transition of the water temperature in the experiment, FIG. 8 shows the transition of the unit width flow rate, and FIG. 9 shows the transition of the downstream water level.

As a result of the experiment, it was observed that the young Ayu was actively going up while passing through the gap 35 of the fishway 100 or jumping on the buffer member 30. In addition to ayu Ayu, Kawamutu, Mokuzugani, Yamatonumae shrimp, Mizorenumae shrimp, Southern shrimp, Gokurakuhaze etc.
The shore portion of the fishway 100 (the supporting member 1 on the slope 80)
(A region near 0) was observed walking uphill.

FIG. 6 shows the results of visually counting the number of test individuals (aquatic organisms) that went up every hour in order to ascertain the status of the upstream and / or descent of the test individuals (aquatic organisms). As shown in FIG. 6, from 16:45 to 17: 4
In one-fifth hour, 3,840 juvenile ayu completed the run-up, and reached 18 in 12 hours from 7:45 to 19:45.
347 juvenile ayu have completed the run-up.

On the other day, the same experiment was carried out for 12 hours a day for one week (one week was fine weather).
It was found that nearly 140,000 juvenile ayus completed the run-up in a week.

Since the buffer member 30 has a configuration in which the gravel 31 is included in the mesh member 32 made of synthetic resin, it has been found that the body of the young Ayu is not hurt.

[0091]

According to the present invention, as the flowing water passes through the gap of the buffer means, the momentum of the flow is absorbed and the flow velocity of the water flowing down the fishway is temporarily reduced. The distribution of the streams within is appropriately regulated, and the ascent and / or descent of aquatic organisms is promoted very effectively.
In addition, since aquatic organisms can pass through the gaps provided by the buffer means, upstream and / or descent is extremely effective not only for crustaceans and benthic fishes that crawl up the riverbed but also for swimming fishes. Promoted. By installing the fishway of the present invention at the edge of the stream, it is possible to more effectively promote the ascent and / or descent of aquatic organisms.

Further, by arranging the buffer means at regular intervals, it is possible to preferably form the distribution of the flow in the fishway, and to promote the ascent and / or descent extremely effectively.

Since the buffer means is detachable, the number of buffer means can be easily adjusted according to the season.

Furthermore, if the kit according to the present invention is used,
It is possible to provide a fishway which assists the ascent and / or descent of aquatic organisms while being simple and extremely effective.

Thus, it is possible to restore or maintain a population of migratory aquatic organisms and to restore or maintain ecosystems in the sea and rivers.

[Brief description of the drawings]

FIG. 1 is a diagram showing a fishway according to the present embodiment.

FIG. 2 is a partially enlarged view of FIG.

FIG. 3 is a diagram of FIG. 2 viewed from a direction B.

FIG. 4 is a diagram illustrating a state in which the fishway of FIG. 1 is installed at a head portion on the upstream and downstream of a river crossing structure.

FIG. 5 is a diagram illustrating a fishway kit according to the present embodiment.

FIG. 6 is a graph showing the results of counting the number of test individuals who went up every hour in an experimental example outdoors.

FIG. 7 is a graph showing changes in water temperature during an experiment.

FIG. 8 is a graph showing a transition of a unit width flow rate during an experiment.

FIG. 9 is a graph showing changes in downstream water level during an experiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 fishway 10, 20 support member 30 buffer member 35 gap 31 filling member 32 mesh member 40a, 40b beam member 13, 23 hole 15, 25 screw 60 kit 61 mesh member 62, 63 support member 69 hole 68 screw

Claims (25)

[Claims] 1. A fishway which is installed at a head portion of a river crossing structure at the upstream and downstream, has at least one portion for reducing flow, and has a portion for relatively promoting flow. 2. The aquatic organisms can stay in the flow relaxing portion, and the aquatic organisms can go up and / or down by swimming or crawling in and / or in the vicinity of the flow promoting portion. Item 1. The fishway according to Item 1. 3. A fishway which is installed in a head-downstream portion of a river crossing structure and has a portion where swimming fish swim and go up and / or down, and a portion where the swimming fish stays. 4. A fishway having a buffer member that is installed at an upper and lower head of a river crossing structure and adjusts a flow state, and a support member that supports the buffer member. 5. A fishway provided at a head portion of a river crossing structure at an upper and lower stream, comprising: a buffer member having a first gap through which flowing water can pass; and a support member supporting the buffer member. The fish passage, wherein the buffer member adjusts a flow state through the first gap. 6. A fishway installed in a head-downstream portion of a river crossing structure, comprising: a buffer member; a support member supporting the buffer member; and a fish passage defined by the buffer member and the support member. A fishway, wherein the buffer member adjusts a flow state, and aquatic organisms can pass through the second gap. 7. A fishway provided at a head portion of a river crossing structure at the upper and lower sides of a river, a buffer member having a first gap through which flowing water can pass, a support member for supporting the buffer member, A buffer member and a second gap defined by the support member, wherein the buffer member adjusts a flow state through the first gap, and the aquatic organism is the second gap. A fishway that can pass through the gap. 8. The fishway according to claim 7, wherein the second gap is formed between the cushioning member and the support member. 9. The fishway according to claim 7, comprising a plurality of said buffer members, wherein said plurality of buffer members are arranged at regular intervals and fixedly supported by said support member. 10. The fishway according to claim 9, wherein the plurality of buffer members are arranged at intervals of 400 mm or more and 550 mm or less and fixedly supported by the support members. 11. A plurality of cushioning members, wherein the plurality of cushioning members are arranged so as to be gradually widened from an upstream side to a downstream side and fixedly supported by the supporting member. Fishway described. 12. The fishway according to claim 4, wherein the cushioning member includes a filling member and a member capable of storing the filling member. 13. The fishway according to claim 12, wherein the member capable of storing the filling member is a mesh member. 14. The net-like member is made of synthetic resin, natural resin, chemical fiber, natural fiber, or metal.
3. Fishway according to 3. 15. The fishway according to claim 4, wherein said support member comprises a pair of hollow rod-shaped members. 16. The fishway according to claim 15, wherein said pair of support members are fixed by a beam member interposed therebetween. 17. The fishway according to claim 4, wherein said support member is provided with fixing means for fixing both ends of said buffer member. 18. The fishway according to claim 1, wherein a river bottom portion of the head portion is inclined. 19. The fishway according to claim 18, wherein said inclination is not more than 50 ° and not less than 10 °. 20. The fishway according to any one of claims 1 to 19, wherein the fishway is detachably mounted on the head portion. 21. A kit for a fishway to be installed at a head drop on the upstream and downstream sides of a river crossing structure, comprising: a plurality of net-like members capable of storing a filling member; and a pair of support members made of a hollow rod-like body. A fixing member for fixing the mesh member to the supporting member, wherein the pair of supporting members includes a receiving means for receiving the fixing member. 22. A fishway provided with adjusting means for adjusting the state of the flow, wherein the adjusting means forms a portion for alleviating the flow and a portion for relatively promoting the flow, and the flow is accelerated. A method of forming a passage through which aquatic organisms can pass by a portion to be made and / or the vicinity thereof, and assisting the ascending and / or descending of aquatic organisms. 23. Forming a first gap through which flowing water can pass, adjusting the state of flow, guiding the flowing water downstream to form a passage through which aquatic organisms can pass, and How to assist up and / or descent. 24. A fishway having a buffer means, a support means for supporting the buffer means, and a second gap defined by the buffer means and the support means, wherein the flow of the water is controlled by the buffer means. A method of adjusting a condition, forming a passage through which the aquatic organism can pass by the second gap, and assisting the ascending and / or descending of the aquatic organism. 25. A buffer installed in a head-downstream portion of a river crossing structure and having a first gap through which flowing water can pass, a support for supporting the buffer, the buffer and the support Means for regulating the flow through said first gap, forming a passage through which aquatic organisms can pass by said second gap. A method of assisting aquatic organisms in ascending and / or descending.