JPH10191817A - Scenery preservative dam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dam capable of achieving scenery preservation and natural protection by floating a floating island on the surface of water in a dammed lake and inserting a fixed stake erected on the dammed lake through a through hole provided on this floating island so as to follow up the water level fluctuation of dammed lake. SOLUTION: For example, a floating island 20 is floated on a water surface 1A of dammed lake 1 and the upper end of fixed stake 25 driven and vertically erected on a lake bottom 12 is passed through a through hole 23 provided on the floating island 20 so that the floating island 20 can be held by the fixed stake 25 so as to be vertically moved in the state of preventing movement from side to side. Concerning the floating island 20, a floating body 21 is banked with soil and vegetation 22 is performed. By holding the floating island 20 like this, the fluctuation in the water level (peak water level H1, water level H2 in case of filled with water and limited water level H3 in summer) of dammed lake 1 can be followed up while fixing the floating island 20 at a prescribed plane position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a landscape preservation dam which is designed to protect a landscape and a nature by providing a floating island in a dam lake.

[0002]

2. Description of the Related Art Dam construction involves submerging a vast area, thereby depriving many habitats of animals and plants and changing the natural scenery. Furthermore, birds of prey that make the area a territory,
It also affects the flora and fauna in the surrounding area. Therefore, as social demands on the environment have increased, efforts have been made to reduce the impact on the natural environment of dams as much as possible. For example, the use of the dam surface itself as well as around the dam has been considered.

Some proposals have been made so far as a method of exerting an environmental conservation function using a dam lake surface. (1) One is to build a Tsukishima island 2 exposed on the water surface 1A in a dam lake 1, as shown in FIG. According to this method, Tsukishima 2 is made by reclaiming embankment, and the most natural state can be created. H2 is the full water level,
H3 indicates a summer limited water level (low water level). (2) As shown in FIG. 13, as shown in FIG. 13, a fixed prop 5 is set up in a shallow water area (for example, a slope 3) of the dam lake 1, and a simple floor is provided thereon for nesting and feeding of water birds. It is to make the platform 4. (3) As another example, as shown in FIG. 14, a raft-shaped floating body 7 made of a drum can or the like is floated on the water surface 1A and an anchor 8 is provided.
And mooring using a wire 9.

[0004]

However, the method (1) requires an enormous amount of earth and sand for the construction of the Tsukishima 2 and the water storage amount depends on the position, scale, size, number, etc. of the Tsukishima 2. It is difficult to realize because it is greatly reduced. In the method (2), since the platform 4 cannot follow the fluctuation of the water level, when the water level decreases, the platform 4 becomes far above the water surface 1A, and the landscape is rather spoiled. In addition, the method (3) can cope with fluctuations in the water level, but when the water level is low, the wire 9 is loosened and the floating body 7 is largely moved, so that the floating body 7 hits the adjacent floating body or lake shore and is easily damaged. It is not suitable for flora and fauna because it moves under the influence of the sea.

[0005] As described above, none of the conventional proposals has achieved a sufficient balance between the original function of the dam (water storage function) and the environment preservation function (function suitable for landscape preservation and flora and fauna habitat). Therefore, at present it is hardly realized.

[0006] Apart from such a problem, in the case of a dam lake, as shown in FIG.
Is always full water level, and H3 is the summer limited water level). A bare land portion (portion without plants) N which repeats submersion and exposure is formed on the shore slope 3, but this portion is eroded by the influence of the waves 10. There was a problem that it was easy to be caused, and it was easy to cause a slope collapse.

The present invention provides a habitat for animals and plants in a form as close as possible to the natural environment without impairing the original function of the dam by providing a floating island capable of following the water level fluctuation of the dam lake in consideration of the above circumstances. Accordingly, it is an object of the present invention to provide a highly feasible landscape preservation dam that can achieve a result of landscape preservation as a result, and also helps prevent a slope from collapsing due to waves.

[0008]

According to the first aspect of the present invention, a floating island is floated on the water surface of a dam lake, and a fixed pile erected on the dam lake is passed through a through hole formed in the floating island to fix the floating island. And is supported so as to be movable up and down in a state in which movement to the side is prevented. In this dam, the floating island follows the water level fluctuation without changing its position on the plane, so that an environment suitable for the habitat of animals and plants can be provided without moving due to the influence of wind waves.

[0009] The invention of claim 2 is characterized in that the floating island is installed near the lake shore so as to minimize the influence of waves on the lake shore.

A third aspect of the present invention is characterized in that a plurality of floating islands are installed along the shoreline of the lake shore to exert a wave-dissipating effect over a wide range and prevent shoreline erosion.

According to a fourth aspect of the present invention, a floating island is provided between a high water level shoreline and a low water level shoreline so as to land at a low water level, and to green a bare land area due to a water level fluctuation at the time of landing. It is characterized by the following.

[0012] The invention of claim 5 is that the upper end of the fixed pile is extended above the highest water level of the dam lake, and a pseudo wood part is provided at that part, so that small birds and birds of prey can rest. Features.

A sixth aspect of the present invention is characterized in that at least the peripheral portion of the upper surface of the floating island is located below the water surface, thereby enabling the growth of wetland plants.

A seventh aspect of the present invention is characterized in that a slope is provided at the edge of the floating island so that chicks and the like of water birds can easily land.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. Drawing 1 is an important section sectional view of a dam lake of a scenery conservation dam of an embodiment. In this dam lake 1, water surface 1A
The floating island 20 is floated on the upper surface, and the through hole 2 provided in the floating island 20 is provided.
The floating island 20 is fixed to the fixed pile 2 by driving the upper end of a vertically mounted fixed pile 25 by driving into the lake bottom 12 of the dam lake.
By 5, it is supported movably up and down in a state where it is prevented from moving sideways.

The floating island 20 is constructed by embankment on a floating body 21 and planting (vegetation 22). Floating body 21
Can be made of various materials such as steel, reinforced plastic, wood, concrete, and the like. Available.

In this example, the floating island 20 is formed in a square shape as shown in FIG. 2, and is stably supported by passing four fixed piles 25 through the through holes 23. The shape of the floating island 20 and the number of the fixed piles 25 are arbitrary.
As shown in FIG. 3A, a rectangular floating island 20A is supported by three fixed piles 25, and as shown in FIG. 3B, a circular floating island 20B is supported by one fixed pile 25. FIG. 3 (c)
As shown in FIG. 7, the gourd-shaped floating island 20C may be supported by two fixed piles 25.

The lower end of the fixed pile 25 may be directly driven into the lake bottom 12 as shown in FIG. 1 or may be fixed via a footing foundation 26 as shown in FIG.

As described above, by supporting the floating island 20, the floating island 20 follows the water level fluctuation of the dam lake 1 in a state where the floating island 20 is fixed at a predetermined plane position. In FIG. 1, the solid line indicates the position when the water level is always full (non-flood season full water level) H2,
The two-dot chain line indicates the position at the summer limited water level H3. Therefore, unlike the method of providing an erected island or the like in the dam lake 1, an environment suitable for habitat of animals and plants can be provided without affecting the water storage amount.

In particular, if the floating island 20 is installed at a location away from the lake shore 13 as shown in FIG. 1, it is safe for birds that are not threatened by humans and terrestrial living organisms (foxes, raccoons, mares, rats, etc.). Can provide a unique habitat. The flora and fauna inhabit as close as possible to the natural environment, thereby preserving a rich and varied natural environment. As a result, the landscape of Dam Lake 1 is preserved.

As shown in FIGS. 5A and 5B,
If at least a part of the peripheral portion where the floating island 20 is in contact with the water surface 1A is formed as a gently sloped slope 27 or small stairs 28, water birds, especially chicks, etc. can land from the water surface.

As shown in FIG. 6, the upper end 25a of the fixed pile 25 is set to be at least higher than the highest water level (surcharge water level) H1 of the dam lake 1, and a horizontal branch or the like is provided at a portion higher than the surcharge water level H1. If the artificial wood part 29 is provided, the water level of the lake surface is high as shown in (a) (H1)
In addition, the artificial wood part 29 can be provided as a watching place for small birds or a resting place on a lake. Also, as shown in (b), when the water level drops significantly and the floating island 20 drops significantly, such as during the summer limited water level, the artificial wood part 29 is used to collect birds 30 such as relatively large birds of prey. It can be used as a bait lookout or a resting place on the lake.

It is also possible to provide a plurality of floating islands on the lake surface and apply different soil and vegetation to each of them. For example, FIG.
In the case of the floating island 20D shown in (a), a terrestrial plant 32 resistant to drying is planted on the gravel-based soil 31. This floating island 20
In D, there is a possibility that birds other than water birds, such as pheasants and pheasants, will fly to the land plants 32. When the protection of wetland plants and the rest and nesting of water birds are mainly used, coconut bark, scab, etc. 33 are provided as shown on the floating island 20E shown in FIG. 7B, and the portion absorbs water. It is surrounded by a wire mesh 35 so that it can be made. Then, earth and sand 34 mainly composed of cohesive soil is put thereon, and wetland plants such as reeds and cattails may be planted there. Planting not only wetland vegetation on the waterside but also terrestrial plants that are resistant to drying can create a rich and varied natural environment. It is also possible to protect the native environment, for example, by transplanting plants that were in submerged areas.

Further, as in the case of a floating island 20F shown in FIG. It is also suitable for the growth and protection of waterside plants, aquatic insects, shellfish, etc.). In the case of a submerged floating island 20F,
After the earth and sand 35 are charged, the scent, palm skin, coconut fiber, etc. 36
To prevent the outflow of the planting base, for example, by holding down the surface layer and further stretching the net 37 thereon.

The floating island may be installed at a place away from the lake shore, but may be installed at a place near the lake shore 13 as shown in FIG. Then, due to the wave-dissipating effect of the floating island 20, a calm water area 40 which is hardly affected by the offshore waves 10 can be secured on the lake shore 13 side.
Therefore, the erosion of the lake shore 13 due to zero can be prevented. In this case, by arranging the plurality of floating islands 20 along the shoreline, the lake shore can be protected over a wide area.

When the floating island 20 is installed at a position near the lake shore (between the shoreline when the water level is high and the shoreline when the water level is low),
As shown in FIG. 9B, when the water level is low H3, the floating island 20
Can reach the bottom of the lake, especially on the slopes 3, creating a situation similar to that of vegetation in areas that were bare at the time of low water levels, There are significant benefits from the natural environment, such as approaches to the environment. In this case, the gap amount between the fixed pile 25 and the through hole 25 of the floating island 20 is determined so that the entire floating island 20 can surely land at the time of the water level drop according to the situation such as the gradient of the lake bottom. It is desirable.

As described above, when the function of preventing erosion due to waves is expected, it is ideal to install the floating islands 20 intensively in an area where severe erosion is expected.
As shown in FIG. 10, not only to prevent erosion, but also from the natural vegetation area on the lake shore to become a conducting wire for approaching small animals to the water surface, and not to create a closed water area from the viewpoint of water quality conservation, The floating islands 20 may be arranged so that the intervals between the floating islands 20 are continuous to some extent. In FIG. 10, reference numeral 41 denotes a shoreline, reference numeral 42 denotes a shoreline when the water level is always full, and reference numeral 43 denotes a shoreline when the water level is limited in summer.

When canceling out the influence of waves, FIG.
The effect is exhibited also in the submerged floating islands 20G and 20H as shown in FIG. In that case, the floating island 20G shown in (a)
The upper surface may be flat and the entire upper surface may be in contact with the water surface 1A, as shown in FIG. 4B. Alternatively, only the center part of the water surface 1A may be formed with a convex curved surface as in the floating island 20H shown in FIG.
A may be contacted. In any case, water surface 1
The presence of the upper surface submerged in A produces a wave suppressing effect.

[0029]

As described above, according to the first aspect of the present invention, the floating island floating on the water surface of the dam lake is supported so as to be movable vertically in a state where the floating island is prevented from moving laterally by the fixed pile. Therefore, the floating island follows the water level fluctuation of the dam lake in a state where the floating island is fixed at the predetermined plane position. Therefore,
Unlike a method of providing a buried island or the like in a dam lake, it is possible to provide an environment suitable for habitat of animals and plants without affecting the water storage amount (without impairing the original function of the dam).

In particular, if a floating island is set up away from the lake shore, it is possible to provide a safe habitat for birds without being threatened by humans and terrestrial living organisms (foxes, raccoons, mares, rats, etc.). It can create a new natural ecosystem that is comparable to submerged areas, especially with water birds, and can be an alternative place for foraging birds such as birds of prey that use the submerged area as a territory. The flora and fauna inhabit as close as possible to the natural environment, thereby preserving a rich and varied natural environment and consequently the landscape of the dam lake.

Further, since the floating island has the effect of canceling waves (wave breaking effect), the water surface can be calmed down, and it is also useful to prevent erosion of the lake shore due to waves. In particular, when the floating island is installed near the lake shore as in the invention of claim 2, the lake shore can be protected from erosion by waves.
Therefore, it is also possible to prevent the outflow of seeds and planting that has been artificially or naturally sprayed on the slope, and the greening and
Planting protection can be promoted, and as a result, erosion due to rainfall and the like can be prevented. Further, if a plurality of floating islands are arranged along the shoreline as in the invention of claim 3, erosion of the shoreline can be prevented continuously, and the slope can be protected over a wide range.

According to the fourth aspect of the present invention, the floating island can be settled on the exposed lake bottom when the water level is low. You can create the same condition as you did.

Also, by preventing erosion of the lake shore, it is possible to form a conducting wire for approaching small animals from the lake shore natural vegetation area to the water surface, and to adapt to the form of the dam, such as creating a rest / nesting place for water birds. Nature conservation and landscape conservation can be achieved.

Further, when the upper end of the fixed pile is extended above the highest water level of the dam lake and a fake xylem is provided at that part, the fake xylem is formed by small birds and birds of prey. Can be provided as a place to rest. Further, by positioning at least the peripheral portion of the upper surface of the floating island below the water surface as in the invention of claim 6, the growth of wetland plants becomes possible. Furthermore, if a slope is provided at the edge of the floating island as in the invention of claim 7, water bird chicks and the like can easily land.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an embodiment of the present invention.

FIG. 2 is a plan view of a floating island in the embodiment.

FIGS. 3A to 3C are plan views illustrating another example of the relationship between the floating island and the fixed pile.

FIG. 4 is a side view showing another fixing example of the fixing pile.

FIGS. 5A and 5B are side views showing an example of a shore of a floating island.

FIG. 6 shows an example in which a pseudo wood part is provided at the upper end of a fixed pile,
(A) is a figure which shows the state at the time of full water, (b) at the time of a low water level.

FIGS. 7A and 7B are cross-sectional views showing specific examples of floating islands.

FIG. 8 is a sectional view showing an example of a submerged floating island.

FIG. 9A is a side view showing an example in which a floating island is installed near a lake shore, and FIG. 9B is a side view showing an example in which a floating island is landed on a lake bottom.

FIG. 10 is a plan view showing an example in which a plurality of floating islands are arranged near a lake shore so as not to form a closed water area.

FIGS. 11A and 11B are cross-sectional views illustrating an example of a submerged floating island effective for canceling waves.

FIG. 12 is a side view showing an example of conventional environmental measures for a dam lake.

FIG. 13 is a side view showing another example of conventional environmental measures for a dam lake.

FIG. 14 is a side view showing still another example of conventional environmental measures for a dam lake.

FIG. 15 is a side view showing the influence of waves on a conventional dam lake.

[Explanation of symbols]

 Reference Signs List 1 dam lake 1A water surface 13 lake shore 20, 20A-20H floating island 23 through hole 25 fixed pile 27 slope (gradient) 28 step (gradient) 29 pseudo-wood part 41 shoreline 42 high-water shoreline 43 low-water shoreline H1 maximum water level H2 water level when full ( High water level) H3 Summer restricted water level (low water level)

Claims (7)

[Claims] 1. A floating island is floated on the water surface of a dam lake, and a fixed pile erected on the dam lake is passed through a through hole provided in the floating island, so that the floating island is prevented from moving laterally by the fixed pile. A landscape conservation dam characterized by being supported vertically movable. 2. The landscape preservation dam according to claim 1, wherein the floating island is installed near a lake shore. 3. The landscape conservation dam according to claim 2, wherein a plurality of said floating islands are installed along a shoreline of a lake shore. 4. The landscape preservation dam according to claim 2, wherein the floating island is provided between a high water level shoreline and a low water level shoreline so that the floating island is settled at a low water level. 5. The landscape preservation dam according to claim 1, wherein an upper end portion of the fixed pile extends above a highest water level of the dam lake, and a dummy wood portion is provided at the upper end portion. 6. The landscape preservation dam according to claim 1, wherein at least a peripheral portion of the upper surface of the floating island is located below the water surface. 7. The landscape preservation dam according to claim 1, wherein a slope is provided at a shore portion of the floating island.