JP2709429B2 - Fish nest block - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a block used for revetment of water channels such as rivers and artificial canals, head works, fishways and the like.
In particular, the present invention relates to a fish nest block suitable for aquatic organisms such as fish, shellfish, and crab.

[0002]

2. Description of the Related Art The following are known as seawalls or head works using conventional fish nest blocks. (1) As described in Japanese Utility Model Laid-Open No. 1-90821, a square box-shaped fish nest block having an internal space surrounded by a wall with an opening is used, and the fish nest block is placed on a slope of a waterway. A seawall with fish nests, which are simply stacked along the front and these fish nest blocks are lined up like a single wall.

(2) As described in Japanese Utility Model Application Laid-Open No. 59-69226, an inclined plate along the slope of a water channel, a vertical wall provided at the rear end thereof, and a horizontal wall extending forward from the upper end of the vertical wall. A fish nest block consisting of a protruding horizontal wall and a space between them is used so that the rear end of the inclined plate of this fish nest block is in contact with the front end of the inclined plate of the next fish nest block. A seawall with fish nests in which the horizontal walls are arranged stepwise by lining up the slopes of waterways.

(3) As described in Japanese Utility Model Laid-Open Publication No. 3-79325, a flat rectangular base, a rear vertical wall and a front vertical wall standing on a rear edge and a front edge, and an upper end of the rear vertical wall. A fish basin formed by using fish nest blocks consisting of horizontal walls continuously provided in a waterway and burying these fish nest blocks in a waterway at intervals.

[0005]

However, the conventional fish nest has the following problems. First, in the revetment with a fish nest described in (1) above, the fish nest is formed inside the fish nest block surrounded, and the shape is quite different from the natural depression, and the internal water is not circulated much. It was difficult to find the best environment for living creatures. In addition, there is also a problem that since the fish nest is hardly exposed to direct sunlight, the water temperature is hardly increased, and the growth of underwater plants such as aquatic plants and algae, which are preferable for aquatic organisms, is poor.

In the seawall with a fish nest of the above (2), the fish nest is formed in the space between the inclined plate and the vertical wall and the horizontal wall of the fish nest block, and particularly, the upper surface of the inclined plate is inclined. Therefore, there is a problem that it is not possible to lay gravel, chestnut stone or cobblestone which is preferable for habitation of fish or the like on this upper surface. In addition, there is a problem that the fish nest block must be manufactured each time the slope angle is adjusted to a different slope angle for each water channel.

In the fish pit of the above (3), the fish nest is formed in a gutter shape by the base of the fish nest block, the left vertical wall and the right vertical wall. 2) The problem with fish nests is improved. However, since no escape route for aquatic organisms was provided anywhere in this fish nest block, there was a problem that the aquatic organisms were trapped in the fish nest when the amount of flowing water in the river was significantly reduced.

Accordingly, an object of the present invention is to form a fish nest close to nature suitable for inhabiting aquatic organisms such as fish, shellfish, crabs and the like by using in seawalls, seawalls, fishways and the like. Another object of the present invention is to provide a new fish nest block that enables aquatic organisms to escape from the fish nest when the amount of water flowing through the water channel is significantly reduced.

[0009]

In order to achieve the above object, a fish nest block according to the present invention comprises a bottom plate, a vertical wall extending upright at the rear edge of the bottom plate and extending in the left-right direction; and支椿wall that projects forward from the upper end of, is erected on the front edge of the bottom plate
And a receiving wall extending in the left-right direction.
An escape route for aquatic organisms is formed in part (claim 1). Further, another fish nest block of the present invention ,
A vertical wall erected on the rear edge of the bottom plate, and from the upper end of the vertical wall
A support wall protruding forward, and a left edge, a right edge or
Is provided with a blocking wall extending in the front-rear direction
In addition, an escape route for aquatic organisms is formed in a part of the blocking wall (claim 2).

Another fish nest block of the present invention is
A plurality of bottom plates spaced apart from each other, and a trailing edge of the bottom plate
And a vertical wall connecting the parts (claim 3).
In this fish nest block, a receiving wall extending in the left-right direction may be provided upright at the front edge of the bottom plate, and an escape route for aquatic organisms may be formed on a part of the receiving wall (claim 4 ). Also,
A blocking wall extending in the front-rear direction may be erected at the left edge, the right edge, or the middle of the bottom wall, and an escape route for aquatic organisms may be formed in a part of the blocking wall (claim 5).

[0011] In each of the fish nest blocks,
The wall or blocking wall may be integrally formed with the bottom plate
But formed separately from the bottom plate and attached to the bottom plate
(Claim 6). It is preferable that at least a part of the surface is provided with irregularities (Claim 7 ). A plurality of convex portions or concave portions are integrally formed on the upper surface of the bottom plate. Attach multiple projections to the top of the bottom. Bottom plate, receiving the attachment of the wall or塞止Me walls or to these, to form water-permeable concrete with irregularities (claim 8). Since a part of the base, the receiving wall, the closing wall, and the like do not receive as much load as the vertical wall and the supporting wall, there is no problem in strength even when formed of permeable concrete. When the base is made of permeable concrete, it is made of carbon, synthetic resin,
It is preferable to use a reinforcing bar made of stainless steel or the like which does not rust.

[0012]

The fish nest blocks according to claim 1 or 2 can be piled up to construct a seawall, a head work or the like, or can be lined up to construct a fishway. When stacking, the bottom plate of the upper fish nest block can be placed and supported on the vertical wall and the upper surface of the support wall of the lower fish nest block.
By changing the relative position of the upper and lower fish nest blocks in the front-rear direction, it is possible to cope with seawalls, head works and the like having different slopes. In addition, the fish nest block according to claim 3 can construct a revetment, a head work and the like simply by arranging the fish nest block.

Further, the fish nest block according to the first, second or third aspect of the invention forms a fish nest close to nature suitable for aquatic organisms such as fish, shellfish and crab for the following reasons. First, a fish nest with a shallow dent close to nature is formed on the upper surface of the bottom plate. On the upper surface of the bottom plate, any of gravel, chestnut stone or cobblestone (in this order, the size increases) can be laid alone or in combination at a uniform height or in an uneven shape. From the viewpoint of giving a change to the fish nest, it is preferable to lay unevenly by combining gravel, chestnut stone or cobblestone.

[0014] Further, since direct sunlight is appropriately applied to the fish nest from above the front edge of the bottom, the water temperature is appropriately increased, and an environment favorable for the growth of underwater plants such as aquatic plants and algae is formed. Also, since the shade is appropriately formed below the support wall, a favorable environment for resting aquatic organisms and the like is formed. In addition, the fish nest has a very good circulation of water, thus creating an environment rich in oxygen and nutrients.

Further, the fish nest block according to claim 3 is
If there is no barrier for aquatic organisms at the front edge of the bottom
In the meantime, aquatic organisms can easily escape from the fish nest by freely passing above the front edge of the bottom when the water flow in the canal is significantly reduced.

Further, according to the fish nest block of the first or fourth aspect , the receiving wall prevents gravel, chestnut stone or cobblestone laid on the bottom from spilling forward, thereby stabilizing the environment of the fish nest. I do. In addition, since an escape route for aquatic organisms is formed in a part of the receiving wall, when the amount of flowing water in the water channel is significantly reduced, the aquatic organisms can escape from the fish nest through the escape route.

According to the fish nest block of the second or fifth aspect , the blocking wall prevents the gravel, chestnut stone or cobblestone laid on the bottom from moving in the left-right direction, so that the environment of the fish nest is stable. I do. In addition, since an escape route for aquatic organisms is formed in a part of the blocking wall, when the amount of flowing water in the water channel is significantly reduced, the aquatic organisms can escape from the fish nests through the escape route.

Further, according to Sakanasu block of claim 6, since the bottom plate of the wall or塞止Me wall receiving formed separately, when forming the Sakanasu block, receiving wall or塞止Me walls Because of the absence, the shape is simplified, and the design and removal of the mold are facilitated.

Further, according to the Sakanasu block of claim 7, since with an uneven least a portion of the surface, increasing surface area of Sakanasu approach the state of natural river bed. Therefore, a fish nest close to nature suitable for inhabiting aquatic organisms can be formed without laying or reducing the amount of gravel, chestnut stone or cobblestone. In addition, when walking along a water channel, it is difficult to slip on the upper surface of the bottom plate, so that a slip-down accident can be prevented. Furthermore, according to the fish nest block of claim 8 , since the bottom plate, the receiving wall or the closing wall, or the attachment to these are formed of uneven permeable concrete, the porosity of oxygen and nutrients can be improved. Supply is improved.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fish nest block according to a first embodiment of the present invention will be described below with reference to FIGS. This fish nest block 1 is formed into a shape as shown in FIG. 1 by concrete in which a reinforcing bar is buried, and the thickness of each part is 200 mm. In addition, the dimensions of each part described below are examples, and can be appropriately changed.

This fish nest block 1 has a horizontal bottom plate 2 formed in a square plate shape, and its length in the left-right direction is 1980.
mm, and the width in the front-rear direction is 2000 mm. A vertical wall 3 extending in the left-right direction is integrally erected at the rear edge of the bottom plate 2,
The height from the bottom of the bottom plate is 1000 mm. Vertical wall 3
A support wall 4 that projects horizontally forward is integrally formed at the upper end, and the width of the protrusion from the rear surface of the vertical wall is 1000 mm.

A receiving wall 5 extending in the left-right direction is integrally erected at the front edge of the bottom plate 2, the length in the left-right direction is 1830 mm shorter than the bottom plate 2, and the height from the top surface of the bottom plate is 3.
00 mm. Therefore, at the front edge, a relief path 6 in the front-rear direction is formed to the right of the receiving wall 5, and the opening width thereof is 150 mm.

A blocking wall 7 extending in the front-rear direction is integrally erected in the middle of the left edge of the bottom plate 2 and has a width in the front-rear direction of 1100 mm shorter than the bottom plate 2 and a height from the top surface of the bottom plate 2. 150 mm. Therefore, at the left edge, between the both ends of the blocking wall 7 and the vertical wall 3 and the receiving wall 5, a lateral relief 8 is formed, and the opening width thereof is 250 mm.

Grooves are formed on the front surface 9 of the support wall 4 and the front surface 10 of the receiving wall 5 at intervals of 100 mm vertically and horizontally to form an irregular surface of a lattice pattern. This uneven surface contributes to the improvement of the landscape and the natural feeling of the fish nest. The bottom plate 2 and the support wall 4 are formed with connection holes 11 for passing bolts connecting the fish nest blocks 1 when the fish nest blocks 1 are stacked up and down.

Now, using the fish nest block 1 of the present embodiment, a seawall with fish nests as shown in FIG. 2 can be constructed. That is, Kuriishi 1 is placed on the lower upper surface of the slope 15 of the waterway.
6 is laid, and a discarded concrete 17 is cast on the chestnut stone 16. A plurality of fish nest blocks 1 are placed and arranged on the upper surface of the discarded concrete 17 with the rear surface of the vertical wall 3 facing the slope 15, and gravel, chestnut stone or cobble stone (hereinafter, chestnut stone) is placed on the upper surface of the bottom plate 2. 18 is used alone or in combination to be laid at a uniform height or in an uneven shape to form the first stage. At a position shifted backward from the first stage, a second stage is formed in a similar manner, and further a third stage is formed.

Further, using the fish nest block 1 of the present embodiment, a head nest with a fish nest as shown in FIG. 3 can be constructed. That is, a step-like concrete base 14 is cast on the step portion of the riverbed 13 so as to extend in the transverse direction of the river. A plurality of fish nest blocks 1 are placed and arranged on the upper surface of each step of the concrete base 14 with the rear surface of the vertical wall 3 facing upstream, and chestnuts and the like 18 are laid on the upper surface of the bottom plate 2. Thereby, the first stage, the second stage, and the third stage are formed.

In the revetment or head work, the second and third fish nest blocks 1 are sufficiently stabilized by their own weight.
However, if these are connected through bolts (not shown) to the connection holes 11 of the upper bottom plate 2 and the lower support wall 4, displacement of the fish nest blocks 1 can be prevented more reliably.
Further, when riverbed scouring, land subsidence, or the like occurs, the connection between the fish nest blocks 1 can be kept flexible. Further, as shown in FIG. 3, an anchor reinforcement 19 which projects rearward is fixed to the Sakanasu block 1 is embedded in the concrete foundation 14, it is preferable to prevent the displacement of Sakanasu block 1 by earth pressure and flow pressure .

The upper fish nest block 1 may be stacked directly above the lower fish nest block 1 or in a staggered manner. In any case, the connection by the bolt is possible. Further, by changing the relative position of the upper and lower fish nest blocks 1 in the front-rear direction, the slope of the revetment or the head work can be easily changed.

Since the fish nest block of this embodiment is constructed as described above, the following functions and effects are obtained. (1) For the following reasons, a fish nest close to nature suitable for aquatic organisms such as fish, shellfish, and crab can be formed over a wide area. On the upper surface of the bottom plate 2 of the fish nest block 1, a shallow and wide depression is formed surrounded by the vertical wall 3, the receiving wall 5, and the closing wall 7, and this depression forms a fish nest close to nature. And since this fish nest is formed for each fish nest block 1 of each stage, the total area becomes very large.

Since the upper surface of the bottom plate 2 is horizontal, it is possible to lay the stones 18 or the like at a uniform height or irregularly as described above. Since the receiving wall 5 prevents the sloping stone 18 and the like 18 from spilling forward and the closing wall 7 prevents movement in the left-right direction, it is held on the upper surface of the base 2. The thus-retained chestnut stone 18 forms a favorable environment for aquatic life activities, spawning and the like.

Since the direct sunlight is appropriately applied to the fish nest from the space between the upper end of the receiving wall 5 and the front end of the support wall 4, the water temperature is appropriately increased, and the environment is good for the growth of underwater plants such as aquatic plants and algae. To form Since a suitable shade is formed below the support wall 4, a favorable environment for resting aquatic organisms is formed. Since the fish nest is a shallow depression along the water stream, the water circulation is very good and creates an environment rich in oxygen and nutrients.

(2) An escape path 6 in the front-rear direction is formed between the adjacent receiving walls 5, and an escape path 8 in the left-right direction is formed on both sides of the blocking wall 7. Aquatic organisms escape from their fish nests when
8 to escape to a lower fish nest or waterway.

Next, in the fish nest block 1 of the second embodiment shown in FIG. 4, the receiving wall and the closing wall are omitted, or
The receiving wall 5 and the closing wall 7 are formed separately from the bottom plate 2,
This is different from the first embodiment in that it is attached to the bottom plate 2 with bolts 12. When the receiving wall or the like is omitted, the aquatic organisms can easily escape above the front edge of the bottom plate 2 when the water is reduced as described above. Further, when the receiving wall 5 and the like are formed separately, when the fish nest block 1 is formed, the shape is simplified by the absence of the receiving wall 5 and the closing wall 7 on the bottom plate 2, and Design and demolding are facilitated.

Next, in the fish nest block 1 of the third embodiment shown in FIG. 5, a rectangular bar-shaped convex strip 21 is fitted into a plurality of mounting grooves 20 formed on the upper surface of the bottom board 2 and extending in the vertical and horizontal directions. Thus, the second embodiment differs from the first embodiment in that the bottom plate 2 is provided with irregularities. According to the present embodiment, the surface area of the fish nest increases and approaches the state of the natural riverbed. Therefore, even if the laying of the rock stone or the like is not performed or the laying amount is reduced, it is close to nature suitable for aquatic organisms. Fish nests are formed. In addition, when walking along a water channel, it is difficult to slip on the upper surface of the bottom plate, so that a slip-down accident can be prevented. When laying stones or the like, the ridge projections 21 extending in the front-rear direction act as blocking walls.

Next, in the fish nest block 1 of the fourth embodiment shown in FIG. 6, the uneven plate 25 and the receiving wall 5 are formed separately from the bottom plate 2 with permeable concrete having unevenness. In that the bottom plate 2 is indirectly provided with irregularities by forming a large number of truncated quadrangular pyramid-shaped convex portions 22 and concave portions 26 on the concave and convex plate 25 by attaching the bolts 12 to the bottom plate 2. This is different from one embodiment. The upper surface of the bottom plate 2 and the lower surface of the support wall 4 are tapered for easy removal during manufacturing. This embodiment has the same effects as those of the second and third embodiments, and the supply of oxygen and nutrients is improved by the porosity of the permeable concrete.

Next, in the fish nest block 1 of the fifth embodiment shown in FIG. 7, the receiving wall 5 to which a small load is applied is formed of permeable concrete having irregularities, and the other portions are formed of ordinary concrete. In addition, this embodiment differs from the first embodiment in that the receiving wall 5 and the bottom plate 2 are provided with irregularities by integrally forming a plurality of ridges 23 extending vertically and horizontally on the upper surface of the bottom plate 2. This embodiment has the same effects as the third embodiment, and the supply of oxygen and nutrients is improved by the porosity of the permeable concrete.

Next, in the fish nest block 1 of the sixth embodiment shown in FIG. 8, the receiving wall 5 and the two closing walls 7 are formed separately from the bottom plate 2 by using irregularly permeable concrete. , The bottom plate 2
The first embodiment is different from the first embodiment in that the receiving wall 5 and the closing wall 7 are provided with a tunnel-like passage hole 27 through which aquatic organisms can pass. This embodiment has the same effect as the fourth embodiment.

Next, in the fish nest block 1 of the seventh embodiment shown in FIG. 9, the upper half of the vertical wall 3 and the support wall 4 are formed separately from the lower half of the vertical wall 3. Bolt 12 in the lower half of wall 3
The two fixing walls 7 are integrally formed at the point fixed by the above and the middle part of the bottom plate 2, and the supporting protrusions 24 protruding from the central part of the both stopping walls 7 and the front edge of the supporting wall 4 abut against each other. Thus, the second embodiment differs from the first embodiment in that the weight of the support wall 4 is additionally supported. This embodiment has the same effects as those of the second and third embodiments.

Next, the fish nest block 31 of the eighth embodiment shown in FIG. 10 will be described. The fish nest block 31 is formed by integrally forming three stages of fish nest blocks, and includes three stages of a bottom plate 2 and a top plate 32 arranged vertically at a pitch of 1000 mm. Length is 200
0 mm and the width in the front-rear direction is 1000 mm. The rear edges of the bottom plate 2 are connected by a tall vertical wall 3 integrally formed therewith. A receiving wall 5 extending in the left-right direction is integrally erected at a front edge portion of the bottom plate 2, and an escape path 6 in the front-rear direction is formed on the left and right sides.

At the center of the fish nest block 31 in the left-right direction, a support wall 33 for connecting and supporting the bottom boards 2 (or the bottom board 2 and the top plate 32) is integrally provided upright. Has a through hole 34 for aquatic organisms. The support wall 33 may be omitted, or may be provided at one or both of the right end and the left end of the fish nest block 31 as shown by a chain line in FIG. Grooves 36 are provided on the left end surfaces of the second and third bottom plates 2 from the bottom so that aquatic organisms can move between the respective stages, and the right end surfaces of the bottom plates 2 are fitted into the through grooves 36 shallowly. A mating projection 37 is provided. Note that the number of stages of the bottom plate 2 can be appropriately changed.

Now, using the fish nest block 31 of this embodiment, a seawall with fish nests as shown in FIG. 11 can be constructed. That is, a concrete base 35 is cast on the lower upper surface of the slope 15 of the waterway, and the concrete base 3
The fish nest blocks 31 are placed and arranged in an inclined state on the upper surface of the block 5. On the upper surface of each bottom plate 2, a rock stone 18 or the like is laid. However, in this construction method, the rock plate 2 is inclined and the rock stone 18 is biased to the rear, so that the upper surface of the bottom plate 2 as in the third to sixth embodiments. It is preferable not to rely on only 18 such as Kuriishi. Further, even if the receiving wall 5 is omitted, 18
Does not spill forward. This embodiment has substantially the same operation and effect as the first embodiment, except that each step is not shifted in the front-rear direction and the left-right direction.

Next, in the fish nest block 41 of the ninth embodiment shown in FIG. 12, the point where the vertical wall 3 is inclined and the receiving wall 5 are formed separately from the bottom plate 2, and the bottom plate 2 is bolted. The eighth embodiment differs from the eighth embodiment in that it is attached at 12, the support wall 33 is omitted, and the uneven member 38 made of permeable concrete is attached to the upper surface of the bottom plate 2 with the bolt 12.
According to the present embodiment, since the vertical wall 3 corresponds to the slope of the slope as it is, the bottom plate 2 is kept substantially horizontal, and there is an effect that it is easy to lay rock stone and the like.

It should be noted that the present invention is not limited to the configuration of the above-described embodiment, but may be embodied with appropriate modifications without departing from the spirit of the invention.

[0044]

The fish nest block according to claims 1 to 5 according to the present invention is constructed as described above, so that it can be used for revetment of a waterway, a head work, a fishway, and the like, and can be used for fish, shellfish, crab, and the like. It has an excellent effect of being able to form a fish nest close to nature suitable for aquatic life . Further, claims 1, 2,
According to the fish nest block described in 4 or 5 , the flow rate of the waterway is
Aquatic organisms escape from fish nests when severely reduced
be able to.

According to the fish nest block of the sixth aspect , when the fish nest block is formed, the design and removal of the mold are facilitated.

Furthermore, according to Sakanasu block according to claim 7, gravel, be reduced even or laying weight without laying Kuriishi or boulders, is close to nature fish nests suitable habitats of aquatic organisms As well as being formed, it is possible to prevent a slide-down accident during walking in a waterway. Further, according to the fish nest block of the eighth aspect , the supply of oxygen and nutrients is improved by the porosity of the permeable concrete.

[Brief description of the drawings]

FIG. 1 is a perspective view of a fish nest block according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a seawall with a fish nest constructed by the fish nest block.

FIG. 3 is a sectional view of a head with a fish nest constructed by the fish nest block.

FIG. 4 is a perspective view of a fish nest block according to a second embodiment.

FIG. 5 is a perspective view of a fish nest block according to a third embodiment.

FIG. 6 is a perspective view of a fish nest block according to a fourth embodiment.

FIG. 7 is a perspective view of a fish nest block according to a fifth embodiment.

FIG. 8 is a perspective view of a fish nest block according to a sixth embodiment.

FIG. 9 is a perspective view of a fish nest block according to a seventh embodiment.

FIG. 10 is a perspective view of a fish nest block according to an eighth embodiment.

FIG. 11 is a sectional view of a seawall with a fish nest constructed by the fish nest block.

FIG. 12 is a perspective view of a fish nest block according to a ninth embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Fish nest block 2 Bottom board 3 Vertical wall 4 Support wall 5 Receiving wall 6 Escape way 7 Closing wall 8 Escape way 20 Mounting groove 21 Convex projection 22 Convex part 23 Convex stripe 24 Support projection 25 Concave plate 26 Depression 31 Fish nest block 38 Irregularities 41 Fish nest block

Claims (8)

(57) [Claims] A bottom wall, a vertical wall erected at a rear edge of the bottom wall, a support wall protruding forward from an upper end of the vertical wall ,
A receiving wall erected on the front edge of the bottom plate and extending in the left-right direction;
And an escape route for aquatic organisms is formed in a part of the receiving wall.
Sakanasu blocks. 2. A bottom plate, and a vertical standing on a rear edge of the bottom plate.
A wall, a projecting from the support wall to the front from the upper end of the vertical wall, the
Front and rear direction standing on the left edge, right edge or midway of the bottom
And a blocking wall extending to the wall, and a part of the blocking wall is aquatic.
A fish nest block with an escape route. 3. The bottom of a plurality of stages vertically spaced apart
A fish nest box comprising a board and a vertical wall connecting a rear edge of the bottom board.
Lock. 4. A catch extending in the left-right direction at the front edge of the bottom plate.
A wall is erected and an escape route for aquatic organisms is formed on a part of the receiving wall.
The fish nest block according to claim 3 formed. 5. The front and rear sides of the baseboard at the left edge, right edge or midway
A blocking wall extending in the direction is erected, and a part of the blocking wall is provided.
The fish nest blow according to claim 3, wherein an escape route for aquatic organisms is formed.
Check. 6. The receiving wall or the cold wall is separate from the bottom plate.
Claim 1 which is formed and attached to the bottom plate.
2. The fish nest block according to 2, 4 or 5. 7. At least a part of a surface has irregularities.
The fish nest block according to any one of claims 1 to 6. 8. A bottom plate, a receiving wall or a cold wall or a bottom wall thereof.
The attachments to them are made of uneven permeable concrete
A fish nest block according to claim 7,