JP5837342B2 - Fishway - Google Patents

Description

  The present invention relates to a fishway that allows fish to go up in places where fish such as rivers provided with structures such as dams are difficult to go up, and more particularly to a fishway constructed using megaliths.

  Conventionally, as a fishway to be provided in a river to help the fish run up, a structure in which a pool portion is formed by providing concrete partition walls at regular intervals in a concrete three-sided waterway has been used. In such a fishway constructed of a concrete structure as a whole, it takes a long construction period and it is difficult to construct it in accordance with the natural environment.

  Therefore, in order to solve these problems, a technique for constructing a fishway by combining a plurality of concrete blocks has been developed. For example, Patent Document 1 proposes that a fishway is configured by arranging a fishway block formed with a water-control projection and a concave portion on a concrete block body in a multi-stage on a sloping waterway. When such a fishway block is used, since the block can be manufactured in a factory in advance, the construction period can be shortened.

  In addition, a dam structure that allows only fish to run up using only natural stones has been proposed as a fishway to be melted into the natural environment. For example, in Patent Document 2, a megalithic dam is arranged in a downstream part of a river, a submerged dam is installed in an upstream part, and the two dams are connected by a stalagmite fishway to form a fishway. The dam is made of natural stone. Moreover, in patent document 3, there exists one which stuffed a small rock in the lower part of a megalith, and fixed the megalith.

JP-A-11-241328 JP-A-2005-133301 Utility Model Registration No. 3144408

  However, in the fishway using a fishway block as in Patent Document 1, in order to configure a plurality of concrete blocks side by side, it is necessary to connect the blocks with fastening hardware and anchor them to the foundation. Therefore, it is necessary to build on the basis of a strong structure already existing in the river, and each block must be connected.

  Moreover, when a fishway is comprised using only a natural stone as shown by patent document 2 and patent document 3, there exists an effect which dissolves a fishway in a natural environment. However, it is not easy to stably fix megaliths, and it was necessary to make the shape of the megalithic lower part into a wedge shape, etc. so that the fixation would be stable when fixing small rocks or the like underneath the megaliths. .

  This invention solves the said subject, The objective provides the fishway which can fix a megalith stably without installing a foundation structure.

A typical configuration according to the present invention for achieving the above-described object is a fishway that is configured by arranging megaliths made of natural stones, and a fixing portion in which paving stones are laid to fix the megaliths to a riverbed portion, A plurality of megalith sets that form a concave-shaped portion toward the downstream by combining a plurality of megaliths that are arranged with their lower portions buried in the fixed portion, and concrete that is placed between the megaliths and above the fixed portion. And a pool portion formed in the concave-shaped portion, and the plurality of megalithic groups are the ones of the megalithic group in which the water flowing between the adjacent megalithic groups upstream is arranged downstream thereof. It is arranged in a staggered pattern so as to enter the pool part.

  In the above configuration, a paving stone is laid on the river bed, and the stable structure of the megalith arranged so that the lower part of the megalith is buried in the paving stone, so that a foundation structure for fixing the megalith becomes unnecessary. Therefore, the installation of megaliths becomes easy and the construction period can be shortened.

  Further, since concrete is placed on the paving stones between the megaliths, the fixing of the megaliths is more stable and the paving stones are not moved by the water flow. Furthermore, the concave portion can be easily formed by placing concrete, and the pool portion can be easily formed.

Further, a megalith set is formed by a plurality of megaliths so as to form a concave shape toward the upstream to form a pool portion, and the water that has flowed between the upstream adjacent megalith sets is arranged downstream of the megalith set Since multiple megalithic groups are arranged in a zigzag pattern so as to enter the pool part of the pool, it is easy to form a pool part for fish to run up, and water is stored in the pool part formed at many places when water is reduced And the water will flow into it, so it won't interfere with the fish going up.

  Moreover, if gravel etc. is laid on the upper part of a concrete part, a concrete part will become invisible, a water flow will also become a natural flow, and a fishway will melt | dissolve by a natural environment.

It is an upper view explanatory drawing of the fishway which concerns on embodiment of this invention. It is side sectional explanatory drawing of the fishway which concerns on embodiment of this invention. It is explanatory drawing which shows the height of each part of the fishway which concerns on embodiment of this invention. It is explanatory drawing of the megalith set which concerns on embodiment of this invention. It is arrangement | positioning explanatory drawing of the megalith set which concerns on embodiment of this invention. It is a partial expansion side sectional explanatory view of each part concerning an embodiment of the present invention.

  Next, an embodiment of a fishway according to the present invention will be specifically described with reference to the drawings. FIG. 1 is a top view explanatory view of a fishway according to an embodiment of the present invention, FIG. 2 is an explanatory side sectional view, and FIG. 3 is an explanatory view showing the approximate height of each part constituting the fishway.

  In the present embodiment, as shown in FIG. 1, a fan-shaped fishway provided in a fan shape toward the downstream riverbed will be described as an example. However, the present invention is not limited to the fan-shaped fishway, but can be applied to other types of fishways such as a full-section fishway.

  As shown in FIGS. 1 and 2, the fishway according to the present embodiment forms a fixed portion by laying a paving stone 2 on the river bed portion 1, and a plurality of megaliths 3 are arranged on the paving stone 2. And between the arranged megaliths, concrete is placed on the paving stone to form a concrete portion, and a pool portion is formed in this concrete portion. Hereinafter, the fishway configuration of the present embodiment will be described along the construction process.

<Laying paving stones>
In the river, a structure such as a dam 4 is constructed with a predetermined step in the entire river width in a direction intersecting the river flow (arrow F) as necessary. In constructing the fishway of this embodiment, first, a paving stone 2 is laid on the river bed portion 1 on the downstream side of the dam 4. This paving stone 2 is a stone having a diameter of about 5 cm to 15 cm, and crushed stone, chestnut stone, cracked stone, cobblestone, etc. can be suitably used. The paving stone 2 is laid on the entire river bed portion 1 forming the fishway so that the height is about several tens of centimeters (in the present embodiment, about 50 centimeters).

  As will be described later, the paving stone layer is formed by first forming a paving stone 2 layer having a predetermined height on the river bed portion 1, placing a megalith 3 on the paving stone layer, and then filling the lower portion of the paving stone 3. Furthermore, paving stones are laid and a paving stone layer having a height of about several tens of centimeters is laid.

  The layer of the laid paving stone 2 becomes a fixing portion for fixing the megalith 3. Therefore, although the size of the above-mentioned size is preferable in order to pack it under the megalith 3, it is not necessary to limit to the said size.

<Arrangement and fixation of megaliths>
The megalith 3 is placed on the paving stone 2 and fixed by a paving stone layer. The megalith 3 is a natural stone, preferably having a diameter of about 0.7 m to 1.5 m and a weight of about 1 t to 5 t, and can be used as it is in a river or the like. Therefore, megaliths can be procured locally without being transported from other locations.

  The megalith 3 used for the fishway of this embodiment is fixed by the weight of the megalith itself by filling the bottom with a paving stone layer. Therefore, if it is too small, it will not be stable even if installed, and conversely if too large, installation itself will be difficult. Accordingly, those having the size and weight described above are preferably used.

  However, the megalith 3 is for relaxing the water force and forming a pool part on the upstream side as will be described later, so the size and weight may be appropriately selected according to the width of the river, the water force, or the amount of water. The size and weight are not necessarily limited to those described above.

  The megalith 3 is fixed by laying a layer of paving stone 2 (first paving stone layer) at a predetermined height (about 20 cm in the present embodiment) on the entire river bed portion 1 forming the fishway, and on the paving stone layer. Place boulder 3 Then, after the arrangement of the megaliths 3 is finished, the paving stones 2 are further set to a predetermined height (about 30 cm in the present embodiment) on the paving stone layer first laid so that the lower part of each megalith 3 is buried at a predetermined depth. Lay the second layer (second paving stone layer). At this time, paving stones are packed between the arranged megaliths, and the lower part of the megaliths 3 is filled with paving stones 2 so that no gap is formed between the megaliths and the paving stone layer. In this way, the lower part of the megalith 3 is backfilled with paving stones by a depth of several tens of centimeters.

  As a result, a paving stone layer having a predetermined height is formed on the river bed portion 1, and the megalith 3 whose lower portion is buried in the paving stone layer is disposed, and the megalith 3 is fixed by the weight of the paving stone layer and the megalith itself. .

  In FIG. 2, the downstream megalith 3 shows a state in which the lower part is filled with the second paving stone layer, and the upstream masonry 3 omits the illustration of the second paving stone layer, and the second paving stone Only the upper part of the layer is indicated by a dashed line.

  Here, the megalith 3 is fixed by laying a paving stone layer of about 50 cm from the beginning on the river bed portion 1 in addition to laying the paving stone layer into the first paving stone layer and the second paving stone layer as described above. It may be configured. In this case, when the megalith 3 is placed on the paving stone 2, the portion of the paving stone 2 where the megalith 3 is placed is dug out by about several tens of centimeters (about 30 cm in the case of this embodiment) to form a recess. By arranging the megalith 3 in the recess, the lower part of the megalith 3 is embedded in the paving stone 2. Furthermore, a paving stone is filled between the arranged megaliths, and the paving stone 2 is buried in a gap between the megalith 3 and a recess formed in the paving stone layer. In this way, the lower part of the megalith 3 may be embedded in the paving stone layer with a depth of several tens of centimeters.

  Thus, in the fishway of this embodiment, since the megalith stable structure is arranged so that the lower part of the megalith 3 is buried in the paving stone layer laid on the river bed, a foundation structure for fixing the megalith 3 is unnecessary. It becomes. Therefore, it is easy to install megaliths, and the construction period can be shortened.

  Moreover, in this embodiment, when arranging the megaliths 3, a plurality of megaliths are combined to form a megalith set that is concave toward the upstream, and the megalith sets are arranged in a staggered manner. .

  Specifically, as shown in FIG. 4, a first megalithic set 5a arranged by combining three megaliths 3 so as to form a concave portion 5a1 that is concave toward the upstream, and 2 on the downstream side thereof. One megalith set 5 is constituted by the second megalith set 5b in which the single megaliths 3 are combined and arranged so as to come into contact with the first megalith set.

  The first boulder set 5a is for forming a pool portion on the upstream side of the boulder, and is formed by combining a plurality of boulders so as to relieve the water force and form a shape that easily collects the water flow.

  On the other hand, the second megalithic set 5b is for supporting the first megalithic set 5a from the downstream side. Therefore, it is desirable that the second megalithic set 5b is more securely fixed than the first megalithic set 5a. For this reason, in this embodiment, each boulder 3 constituting the second boulder set 5b is buried and fixed deeper than each boulder 3 constituting the first boulder set 5a. Thereby, the megaliths constituting the second megalithic set 5b are fixed more stably than the megaliths of the first megalithic set 5a, and the concave portion 5a1 reliably supports the first megalithic set 5a that is easily affected by the water flow from the downstream.

  In addition, if the stones heavier than the megalithic stones of the first megalithic group are used as the megalithic stones of the second megalithic group, the megalithic stones of the first megalithic group can be used without deeply embedding the megalithic stones of the second megalithic group as described above It can be reliably supported from the downstream side.

  In the present embodiment, the first megalithic set 5a is composed of three megaliths, and the second megalithic set 5b is composed of two megaliths, but the number of these megaliths needs to be limited to the above number. The first megalithic set 5a and the second megalithic set 5b may be configured by combining several megaliths as appropriate.

  As described above, the megalithic groups 5 including the first megalithic groups 5a and the second megalithic groups 5b are arranged in a staggered manner as shown in FIG. That is, the megalith set 5 is arranged at a predetermined interval in the river width direction of the river, and the slit portion 6 is formed between the adjacent megalith sets 5 as a passage through which fish goes up. And the next megalith set 5 is arrange | positioned downstream of the said slit part 6, and it has arrange | positioned so that the water which flowed through the slit part 6 may enter into the recessed part 5a1 of the megalith set 5 arrange | positioned downstream.

  If the width of the slit portion 6 is too wide, the water cannot be relaxed, and if the width is too narrow, it is difficult for the fish to go up. Therefore, in this embodiment, the megalith set 5 is arranged so that the width of the slit portion 6 is about 30 cm to 50 cm. Then, as shown in FIGS. 1 and 2, the megalith set 5 is arranged in a fan shape on the downstream side of the dam 4 and so as to increase stepwise from the downstream side to the upstream side to constitute a fishway.

<Formation of concrete part>
After arranging and fixing the megalith assembly 5 as described above, concrete is placed by placing concrete at a predetermined height (in this embodiment, about 30 cm, see FIG. 3) between the megaliths and on the paving stone layer. Form. By providing the concrete portion 7 on the paving stone layer in this manner, there is no possibility that the paving stone 2 moves or the river bed portion is swept away even in a river with a rapid flow. Furthermore, megalith 3 can be more stably fixed by fixing between megaliths with concrete.

  And when forming the concrete part 7, after removing the paving stone 2 of this part so that the part of the recessed part 5a1 of the 1st boulder set 5a may become predetermined depth, concrete is laid by predetermined height. Thereby, as shown in FIG. 6, the recessed part 5a1 becomes lower than other parts, and the pool part 8 in which the fish which goes up here can rest is formed. In the present embodiment, the depth D of the pool portion 8 is set to about 20 cm to 30 cm.

  By providing the concrete part 7, the pool part 8 can be easily formed. That is, a pool portion having a predetermined depth can be easily formed in the recess 5a1 simply by removing the paving stone 2 of the recess 5a1 and placing concrete.

  In the present embodiment, since the pool portion 8 is formed by the concrete portion 7 placed on the paving stone layer, the water stored in the pool portion 8 does not soak into the paving stone layer. And since the water which flowed through the slit part 6 is guided to the pool part 8 located in the downstream of the slit part 6, even if it is a river with a weak water flow or a river with a small amount of water in the dry season, Water will be stored reliably.

  For this reason, even when the amount of water is reduced, the fish can move sequentially from the downstream pool section 8 to the upstream pool section 8, and the run-up is not hindered.

<Laying of cutting gravel>
Furthermore, as shown in FIG. 6, the fishway of this embodiment lays the cutting gravel 9 on the concrete part to form a cutting gravel layer having a height of about 10 cm. As a result, the concrete portion 7 is not exposed, and only the megalith 3 made of natural stone and the cut gravel 9 are exposed from the entire fishway.

  For this reason, the entire fishway will be integrated into the natural environment, and the river flow will be natural, so that it will be easier to go up the fish.

DESCRIPTION OF SYMBOLS 1 ... River bed part 2 ... Paving stone 3 ... Megalithic stone 4 ... Weir 5

Claims (3)

In a fishway that consists of huge stones made of natural stone,
A fixing part in which a paving stone is laid to fix the megalith on the river bed ,
A plurality of megalithic groups that form a concave-shaped portion toward the downstream by combining a plurality of megaliths arranged with the lower portion buried in the fixed portion, and
A concrete portion placed between the boulders and placed on top of the fixed portion;
A pool portion formed in the concave shape portion;
Have
The plurality of megalithic groups are arranged in a staggered manner so that water flowing between adjacent upstream megalithic groups enters the pool part of the megalithic group arranged downstream thereof. .   The boulder set is composed of a first boulder set that forms a concave shape downstream with several boulders, and a few boulders that are arranged on the downstream side of the first boulder set and support the first boulder set. The fishway according to claim 1, comprising: a second megalithic set.   The fishway according to claim 1 or 2, wherein cutting gravel is laid on the concrete part.

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