JP2007029058A - Artificial floating island for submerged plant, method for forming submerged plant community by using the same, and method for cleaning water by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To protect an artificial floating island for a submerged plant from an animal eating the submerged plant as food or the like, and to reconstruct the community of the submerged plants at a set water area. <P>SOLUTION: The artificial floating island 10 for the submerged plant is constituted of a float 40, a frame 31 and the like, and a vegetation base plate 20 is provided in the frame 31 so that the water depth may be changed deeply and shallowly. A net 51 for blocking the fish eating the submerged plant as a food is provided at the submerged part, and a net 52 for preventing the submerged plant from being disturbed by a water bird is provided above the net. The submerged plant is raised at the position with a shallow depth at which the transmittance of the light is good at the initial time when the transparency is bad, and the depth is gradually deepened as the improvement of the transparency according to the growth. The seeds and the like of the submerged plant are dispersed to the water bottom to form the community at the environment, and thereafter the artificial floating island 10 for the submerged plant is removed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a technique related to an artificial floating island, and is particularly effective when applied to secure a planting environment suitable for a submerged plant, promote the formation of a submerged plant, and promote water purification efficiently.

  Artificial floating islands that float artificial floating bodies in ponds, lakes, rivers, etc., and plant extraction plants such as reeds and kishobu, have functions such as water purification, biological habitat, wave suppression, landscape improvement, etc. It is applied as a water purification and wave-dissipating structure in closed waters. Various structures have been proposed for such artificial floating islands.

  On the other hand, submerged plants in the waterside such as axle algae, chromo, fusamo, shrimp, etc. (Submerged plants are basically plants that have roots, stems, and leaves under the surface of the water. (There are some species that have leaf tips on the surface of the water and some species that bloom flowers on the surface of the water, such as spider spiders.) As for the communities, the bottom of these submerged plant communities inhabited by the decrease in transparency due to the pollution of the closed waters. As a result, many of them disappeared. Currently submerged plants are threatened with extinction and extinction throughout the country. In Japan, 1/3 of aquatic plants are listed in the Red Data Book.

  Recently, these submerged plant communities have various functions including water purification such as uptake of nutrients in the water, prevention of rolling up of bottom mud, zooplankton retreat, benthic itch house, etc. It has become clear. Along with the conservation of biodiversity, an attempt to restore waterside vegetation zones, including submerged plant communities, has begun as a nature restoration project.

As a planting base of a submerged plant, for example, Patent Document 1 discloses a configuration in which the planting base can be moved up and down so that an appropriate water level change of the planting base can be obtained. Moreover, although there is no statement as a submerged plant in patent document 2, what seems to be a submerged plant because the whole is submerged in water is a vegetation base with a weight that is gently inclined from the surface of the water toward the water. The growing configuration is disclosed.
JP-A-11-275990 JP 2002-119157 A

  The inventor of the present application has found that there are the following problems regarding the regeneration and restoration of submerged plants.

  In other words, in water areas where restoration is attempted, water pollution has advanced considerably and transparency is low. For this reason, submerged plant communities cannot grow in the deep water areas where they have traditionally inhabited because light does not reach them. Although depending on the transparency of the water area, for example, even if seedlings and seeds are sprayed, they can germinate and grow only in a shallow water area of about 30 cm in depth.

  At the beginning of planting and seed dispersal, submerged plant communities are once regenerated, but at such shallow depths, water-drawn plants such as reeds and floating leaf plants such as casters can grow. As a result of overgrowth, sufficient light cannot be obtained and vanishes. Great challenges remain in the regeneration and restoration of submerged plant communities.

  So far, floating islands that restore aquatic plant communities including submerged plants have been proposed, but for example, in the configuration of the floating island structure described in Patent Documents 1 and 2, because the focus is on the extracted plants and vegetation transition zone, It does not necessarily focus on the restoration of submerged plants. Therefore, the details of what is the optimal planting base for submerged plants are not known.

  Therefore, as a result of various studies and investigations regarding the planting base of submerged plants, the present inventor has found that there are the following problems. This problem was obtained as a result of previous attempts to regenerate submerged plant counties in the coastal area of the lake, and it can be said that regeneration and restoration are difficult with the conventional floating island structure.

Damage caused by herbivorous and omnivorous fish on submerged plants Herbivorous fish such as grass carp and omnivorous fish such as clams are artificially released in order to remove aquatic plants that have flourished in lakes and the like in the past. Has disappeared. In such a water area containing edible fish, it is not possible to grow submerged plants without taking intrusion prevention measures when setting up floating islands for submerged plants as well as planting in coastal areas.

Predation of zooplankton grown in a submerged plant community by collecting plankton-eating fish In a submerged plant community, it is known that zooplankton that prey on phytoplankton (which has water purification effects) grows. Yes. However, if a large number of omnivorous and zooplankton-eating fishes are collected even before the plant community has grown, the zooplankton will be consumed, and the water purification function by the zooplankton will not be fully demonstrated. It is necessary to take measures to prevent such fish.

Damage of submerged plants by birds such as ducks and disturbance of planting bases Birds such as ducks not only make floating islands a nesting and resting place, but also feed on aquatic plants. In addition, swimming in the floating islands disturbs the planting base on which submerged plants in the early stage of growth, such as roughening with water scraping or pulling out planted submerged plants with beaks, are planted. It is necessary to prevent such disturbance.

The depth of viable water varies depending on the plant species and water quality The degree of pollution varies depending on the water quality of the water area, and the water depth through which light passes varies greatly. Since the light requirement varies depending on the submerged plant species and its growth stage, it is necessary to move the planting base up and down.

The limit of overgrowth of submerged plants due to the influence of wind waves As a problem in restoring submerged plant communities, there is the limit of overgrowth of plants due to the effects of wind waves. In a strong wind and wave area, the planting base moves, and the ability of the roots of submerged plant communities to stick is very poor. For this reason, for example, in order to restore submerged plant communities in coastal areas such as Kasumigaura, wave-dissipating facilities such as rough ridges are required. In the conventional floating island structure, these wave-dissipating functions are not taken into consideration, and it can be said that it is very difficult to grow a submerged plant community at a point where such a wind wave is strong.

Bringing submerged plant species from other waters In the past floating islands, seeds were thrown into the form of planting grown seedlings or soil. In commercial products, such seedlings and seeds are not from the waters that are desired to be restored, which leads to the transfer of submerged plant species from other waters, resulting in genetic disturbances that do not restore native species . This is different from natural regeneration in the original sense.

  Thus, there are many problems to be solved in the construction of the artificial floating island for submerged plants, and the water purification effect such as improvement of water pollution by submerged plants is performed for the first time through the solution of such problems.

  An object of the present invention is to protect an artificial floating island for a submerged plant from animals that feed on the submerged plant.

  Another object of the present invention is to appropriately perform formation including restoration of a submerged plant community in a water area using an artificial floating island for a submerged plant.

  Another object of the present invention is to appropriately purify water in an installation water area using an artificial floating island for a submerged plant.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  The present invention is an artificial floating island for a submerged plant having a planting base for planting a submerged plant, wherein the submerged portion of the planting base is surrounded by a net so that animals that feed on the submerged plant do not enter. It is characterized by. In such a configuration, the net has a mesh size of 1 mm or more and 100 mm or less. Further, the present invention is an artificial floating island for a submerged plant having a planting base for planting a submerged plant, and the upper part of the planting base is a net so that birds feeding on the submerged plant cannot enter. It is characterized by enclosing. In such a configuration, the net has a mesh size of 5 mm or more and 200 mm or less.

Further, the present invention is an artificial floating island for a submerged plant having a planting base for planting a submerged plant, wherein the submerged portion of the planting base is placed on a net so that animals that feed on the submerged plant do not enter. The upper part of the planting base is surrounded by a net so that birds that disturb the submerged plant do not enter. An artificial floating island for submerged plants having a planting base for planting submerged plants,
The submerged portion of the planting base is surrounded by a net so that fish that feed on zooplankton that uses the submerged plant as a place of life is not inserted, and the upper part of the planting base is a bird that disturbs the submerged plant It is characterized by enclosing it with a net so as not to enter.

  The present invention is an artificial floating island for a submerged plant having a planting base for a submerged plant for planting a submerged plant, wherein the planting base for a submerged plant is surrounded by a wave-dissipating function. . In such a configuration, when the wave height to the artificial floating island for the submerged plant is higher than the wave height at the growth limit of the submerged plant, the wave-dissipating function product has a direction in which a wave higher than the wave height at the growth limit of the submerged plant comes. It is characterized by providing in. When the wave height to the artificial floating island for the submerged plant is lower than the wave height at the growth limit of the submerged plant, the wave-dissipating function has the highest wave height among the wave heights to the artificial floating island for the submerged plant. It is provided in a direction. As described above, in any one of the configurations, the wave-dissipating function product is an artificial floating island for a water extraction plant in which the water extraction plant is planted on a planting base. The present invention is an artificial floating island for a submerged plant having a planting base for a submerged plant for planting a submerged plant, and the planting base for a submerged plant is an artificial floating island for a submerged plant that is planted on a planting base. It is characterized by being juxtaposed.

  The present invention is an artificial floating island for a submerged plant having a planting base for a submerged plant for planting a submerged plant, wherein the submerged plant is planted on a planting material such as sponge, rock wool, slag wool, and the submerged plant is planted. The planted material is placed in the planting base for the submerged plant. Further, the present invention is an artificial floating island for a submerged plant having a planting base for a submerged plant for planting a submerged plant, wherein the submerged plant is collected from the bottom of a water area where the planting base for the submerged plant is installed. It is characterized by germinating submerged plant seeds contained in the earth and sand.

  The present invention provides the planting base of the artificial floating island for submerged plants in which the submerged plant is planted as the limit water depth of the light transmittance capable of growing the submerged plant becomes deeper as the submerged plant grows. A step of deepening within a range, a step of scattering seeds or spores of the submerged plant planted on the planting base to a bottom of the water, and a step of growing a submerged plant on the bottom of the water based on the scattered seeds or spores. It is the formation method of a submerged plant group using the artificial floating island for submerged plants characterized by this. In this configuration, the planting base is removed when a submerged plant is rooted on the water bottom. In such a configuration, the limit water depth of the light transmittance at which the submerged plant can grow is a water depth at which the light transmittance is 20% or more. In this configuration, the submerged plant is characterized by germinating a submerged plant seed contained in the earth and sand collected from the bottom of the water area where the planting base for the submerged plant is installed.

  The present invention is a method for purifying water quality using an artificial floating island for a submerged plant planted on a planting base of a submerged plant, and in the submerged plant planted on the planting base of the artificial floating island for the submerged plant, It is a water purification method using an artificial floating island for submerged plants, characterized in that zooplankton is brought in from outside. In this configuration, the zooplankton is generated using bottom mud collected from the bottom of the target water area where the artificial floating island for submerged plants is installed. In this configuration, the submerged plant is characterized by germinating a submerged plant seed contained in the earth and sand collected from the bottom of the water area where the artificial floating island for the submerged plant is installed.

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  In the configuration of the artificial floating island for submerged plants according to the present invention, the submerged plant itself can be protected from an animal that feeds the submerged plant by adding a simple configuration to provide a net. The planting state can be managed. In particular, in a water area where the influence of wind waves is strong, the normal growth state of the artificial floating island for submerged plants can be ensured by placing a planting base on which a water extraction plant is planted. In addition, even in water areas that are not affected by wind waves, subsidence can be achieved by increasing the transparency by using the purification effect mainly due to the shading effect by floating islands for the extraction plants by placing a planting base on which the extraction plants have been planted. It can promote the early growth of plants.

  According to the present invention, it is possible to form a submerged plant community in an installation water area of an artificial floating island for a submerged plant. In particular, by using a submerged plant sprouted from the sediment at the bottom of the water area of the artificial floating island for submerged plants, it is possible to regenerate and restore nature in the water area.

  According to the present invention, since zooplankton is introduced into the submerged plant from the outside, the function of purifying water quality can be exhibited even in a water environment such as a low density or type of zooplankton.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof may be omitted.

  The present invention solves the structural problems of an artificial floating island for a submerged plant and installs the planting base of the submerged plant community at a water depth that can ensure the light conditions necessary for the growth of the submerged plant. By planting only an artificial floating island, it is possible to prevent submerged plants and floating leaf plants from entering, and as a result, to form submerged plant communities that include restoring submerged plant communities to the bottom of the water area. In addition, even when using artificial floating islands for submerged plants and artificial floating islands for extracted plants as a set, it is possible to prevent the intrusion of extracted plants by partitioning the artificial floating island for submerged plants. Can be secured.

  Furthermore, in the purification of water quality such as ponds and lakes and marshes using such artificial floating islands for submerged plants, one of the water purification functions of submerged plant communities has a function as a hideout for zooplankton with high water purification capability. We also propose a method that can enhance the purification function even in waters where the density and number of plankton are very small, or where only small zooplankton communities exist.

  That is, according to the present invention, the following effects can be obtained. It is possible to ensure the stability of the planting base by putting sand, soil or lightweight aggregate into the porous member, prevent the sand and soil from disappearing due to waves etc., and promote the growth of submerged plants. . Filling a submerged plant planting pod filled with sand or lightweight aggregate can significantly reduce the amount of sand filling, reduce the size of the floating body as the weight is reduced, and reduce costs Can be. By changing the position of the planting base according to the water quality and the growth stage of the plant, the growth of the submerged plant can be promoted.

  It prevents herbivorous, omnivorous and zooplankton-eating fish from entering the floating islands and promotes the growth of submerged plants. Predation from birds, planting base disturbance can be prevented, and the growth of submerged plants can be promoted.

  Effectively purify the target water area, and finally regenerate submerged plant communities on the bottom of the floating island for submerged plants, enhance the water purification function of the ecosystem, and restore the submerged plant communities throughout the water area Can do. The submerged plant community peculiar to the water area can be restored to the submerged plant floating island. Even when the seeds (buried seeds) contained in the bottom sediment of the water area are small, it is possible to effectively restore the native (water area specific) submerged plant community by germination, breeding and seedling planting. A community of native submerged plants can be restored to the bottom of the floating island, expanded to the entire body of water, and a native submerged plant community can be restored. Such water purification and restoration speed can be increased.

  The water purification effect that is different from the wave extinction of submerged floating islands and submerged plants enables more effective and effective water purification.

  Zooplankton such as Daphnia, which eats phytoplankton, particularly large Daphnia can be increased, and the water purification effect of floating islands for submerged plants can be enhanced. By using the native zooplankton community that has been generated and cultured, the problem of introgression from other species is also eliminated.

  Hereinafter, the present invention will be described more specifically by describing each embodiment in relation to such effects.

(Embodiment 1)
FIG. 1 is a side view schematically showing an example of an artificial floating island for a submerged plant according to an embodiment of the present invention. FIG. 2A is a perspective view showing the structure of a float and its frame used in the present invention, and FIG. 2B is a perspective view showing a situation where a planting base is provided in the frame. 3 (a) and 3 (b) are explanatory views showing the situation where the water level is adjusted in the present invention.

  The basic structure of the artificial floating island 10 for a submerged plant includes a planting base 20 on which a submerged plant is grown, a support 30 that supports the submerged plant, and a float 40 that serves as a floating body for maintaining the structure in water. .

  The material of the float 40 is a hollow pipe 40a such as a PVC pipe, or foamed polystyrene, wood, old tires, etc., and the buoyancy that can float the entire structure of the artificial floating island 10 for submerged plants including the planting base 20 and the like. Any material that has

  As shown in FIGS. 2A and 2B, the support 30 is composed of an angle 31 a constituting the frame 31, a blue sheet 32 a constituting a sheet 32 surrounding the planting base 20 and the like. The angle 31a is formed of steel, plastic, wood, or the like, and is combined in a frame shape to form a frame 31 as shown in FIG. In particular, in a place where wind waves or the like are a problem, a plastic having a sufficient strength and non-biodegradable plastic is used. Such a frame 31 is connected to the float 40.

  Moreover, the sheet | seat 32 is provided in the lower part and side surface of the planting base 20, and the outflow of the sand and soil with which the planting base 20 was filled, or a lightweight aggregate is prevented. As the material of the sheet 32, a water-proof sheet such as a blue sheet or a construction sheet used in construction or civil engineering may be used.

  As for the planting base 20, the porous member 20a is filled with sand, earth, lightweight aggregate or the like. As the porous member 20a, for example, a lightweight chemical synthetic mat or a palm fiber mat can be used. The sand or the like to be filled in the planting base 20 can be filled with soil and sand at the bottom of the area where the artificial floating island 10 for submerged plants is installed. By using the porous member 20a, it is possible to prevent the soil and sand filled with wind waves or the like from flowing out of the base of the lightweight aggregate, and to stabilize the planting base 20.

  By the way, lightweight aggregate is made of glass, expanded shale, etc. as a raw material, and there is a void in the inside obtained by artificial firing and foaming, and the surface is covered with dense glass, lighter and stronger bone than sand It is a material. Mesalite, G light, Asano superlight, etc. are known as common product names.

  Further, the porous member 20a may be filled with a material obtained by filling the planting pod 21 with earth and sand without directly filling the porous member 20a with earth and sand. If this structure is employ | adopted, the weight reduction of the planting base 20 can be achieved.

  The thickness of the planting base 20 is set to be equal to or greater than a thickness that allows the roots of the submerged plant to be sufficiently stretched. Depending on the type of submerged plant, on average, it may be, for example, 5 cm or more. The planting pod 21 may be a pod used in horticulture such as cloth, woven fabric or palm fiber. What is necessary is just to fill this planting pod 21 with sand. By using the planting pod 21, the amount of sand and earth and sand used can be greatly reduced.

  Or it can plant without using soil by using planting materials, such as sponge, rock wool, and slag wool, instead of using filling pods, such as planting pod 21. That is, a seed, spore, or seedling of a submerged plant is planted without using soil using a plant material such as rock wool. What is necessary is just to provide this planted planting material, for example so that it may be put in predetermined positions, such as the chemical synthetic fiber mat of the planting base 20, and the mat | matte made from palm fiber. By using a planting material such as sponge, rock wool, slag wool or the like instead of the planting pod 21, the amount of earth and sand to be used can be made zero.

  Thus, by reducing the amount of earth and sand to zero or greatly, the planting base 20 can be reduced in weight, the floating equipment such as the float 40 can be reduced, and the layer thickness of the planting base 20 can be increased. It becomes.

  When the planting base 20 or the planting pod 21 is filled with sand, mountain sand or river sand is preferable. Sea sand is not preferred because salinity inhibits the growth of submerged plants. However, there are cases where seeds of aquatic plants are mixed in the river sand, so care must be taken when restoring the submerged plants in the installation water area. In addition, when using commercially available products for both sand and earth, it is better not to use alkaline ones with a low content of calcium or the like, paying attention to the component labeling.

  In order to plant a submerged plant on the planting base 20 or the like, a seedling is planted directly on the planting base 20 in which the porous member 20a is filled with sand or light aggregate. Or after planting a seedling in the planting pod 21, it is good to plant by the method of filling the porous member 20a.

  In such planting, when a large amount of seeds and spores of conventional submerged plants are present as buried seeds in the soil collected from the bottom of the target water area of the submerged artificial floating island 10, the bottom of the porous member 20 a is submerged. Filling the collected soil and sand is preferable because various native species peculiar to the water area can be restored to the artificial floating island 10 for a submerged plant.

  In addition, when only a small amount of buried seed is contained in the earth and sand collected from the bottom of the target water area of the artificial floating island 10 for submerged plants, the earth and sand collected in advance from the bottom of the water is excavated to a depth of about 20 cm to make the water impermeable. It is spread on a place where a sheet is laid or a large bud, is filled with water, and a native submerged plant is germinated under sufficient light conditions. The seedling of the submerged plant that has sprouted and grown is directly planted on the planting base 20 in which the porous member 20a is filled with sand or light aggregate. Or after planting in the planting pod 21, the planting pod 21 may be filled in the porous member 20a. When such a method is employed, the conventional submerged submerged plants existing in the water area where the artificial floating island 10 for submerged plants is installed can be restored.

  The connection position of the frame 31 supporting the planting base 20 and the frame 31 connected to the float 40 is configured to be variable up and down. That is, as shown in FIGS. 3A and 3B, the frame 31 can be adjusted up and down to adjust the installation water depth of the planting base 20. As the water depth variable means of the planting base 20, for example, the angles 33 with holes at regular intervals are provided at the four corners of the frame 31 and connected to the float 40, and connected to the frame 31 that supports the planting base 20. The angle 34 may be fixed at an appropriate height with a bolt 35 or the like.

  Since the viable depth of aquatic plants varies greatly depending on the water quality, the light transmittance was adopted as a standard for determining whether or not the plants can grow. That is, if the water depth is 2% or more, more preferably 20% or more of the water surface, the growth limit water depth at which a submerged plant can grow can be obtained.

  It is preferable to reduce the water depth as much as possible at the beginning of planting and the early stage of germination, and to promote the growth of plants at a shallow water depth that is sufficiently exposed to light even when the light transmittance is 20% or more. As the stem length increases, it is desirable to increase the depth of installation of the planting base 20 up to the depth of 20% of the light transmittance.

  In addition, by creating a gradient in the planting base 20, a place with different light conditions is formed in the planting base 20, and in this configuration, various submerged plant communities according to the water depth are created in the same planting base 20. It does not matter if it is possible to do. FIG. 4 shows a list of aquatic plants including submerged plants.

  As shown in FIG. 1, the submerged artificial island 10 for a submerged plant is covered with a net 51 having a mesh size of 1 mm or more and 100 mm or less from the bottom of the planting base 20 to the water surface. . More preferably, the net is 5 mm or more and 50 mm or less. The material of the net 51 may be hard or soft, such as polyethylene, polypropylene, and palm fiber. The material is preferably a material that is hardly decomposable, water resistant, or ultraviolet resistant.

  The mesh size should be small, but if it is too fine, the flow of water in the floating island will be hindered, so it is desirable that the hole diameter is 1 mm or more, and the body length of the fish to be prevented from entering is 100 mm or less. Furthermore, it is more preferable if it is 5 mm or more and 50 mm or less. If it is 5 mm or more, the smoothness of entering and exiting water is ensured, and if it is 50 mm or less, it is possible to focus on fish with a short body length, such as grass fish, which are particularly damaging to submerged plants, and fish that eat zooplankton. preferable.

  By providing such a net 51, it is possible to prevent herbivorous fish that inhibit the growth of submerged plants and fish that prey on zooplankton that live in submerged plants from entering the planting base 20 in the floating island. it can.

  In addition to fish such as grass fish, the net 51 can prevent intrusion of crayfish such as crayfish, and can prevent damage such as rooting of a submerged plant of crayfish and stalk cutting.

  Further, as shown in FIG. 1, a net 52 having a mesh size of 5 mm or more and 200 mm or less, more preferably 10 mm or more and 100 mm or less is also provided above the planting base 20. Considering the state of sunlight transmission, a mesh size of less than 5 mm is not preferable. More preferably, 10 mm or more is sufficient. On the other hand, if the mesh size is larger than 200 mm, water birds or the like may enter and disturb the submerged plant planting base 20 when fishing for food or the like. More preferably, if the mesh size is 100 mm or less, a small bird such as a duck can be used as an intrusion prevention target.

  The material of the net 52 may be hard or soft, such as polyethylene, polypropylene, and palm fiber. It is preferable to use a material that is hardly decomposed and resistant to ultraviolet light. In addition, when the net 52 is thick, it is preferable to use a strong and narrow net 52 because it prevents light from being transmitted to submerged plant communities in the floating island base.

  The place where the net 52 is installed may be anywhere above the planting base 20 as long as it does not hinder the growth of submerged plants. From the viewpoint of landscape protection, it is desirable to install it below the float and below the surface of the water. By installing this net 52, it is possible to minimize the adverse effects of water birds such as ducks and birds that prey on aquatic plants or break into floating islands and disturb planting base 20, and birds. Germination and growth of communities can be promoted.

  Incidentally, if such bird damage does not occur or does not become a problem, it is of course unnecessary to install the net 52. In FIGS. 3A and 3B, an example in which the net 52 is not configured is used.

(Embodiment 2)
In the present embodiment, a configuration in which the artificial floating island 10 for a submerged plant and the artificial floating island 60 for a drained plant are juxtaposed will be described. By adopting such a configuration, for example, the effects of wind waves on the planting base 20 of the artificial floating island 10 for the submerged plant 10 are reduced, and the transparency of the water is improved by the action of the artificial floating island 60 for the drained plant. It can be made easier to grow. FIG. 5 is an explanatory diagram showing a configuration in which an artificial floating island for a water extraction plant is provided in a direction in which the influence of wind waves or the like of the artificial floating island for a submerged plant is large. FIG. 6 is an explanatory diagram showing a configuration for protecting an artificial floating island for a submerged plant against waves hitting toward the shore.

  In the present embodiment, an artificial floating island 60 for a water extraction plant is provided as a wave-dissipating function for the higher wave that hits the artificial floating island 10 for a submerged plant. The artificial floating island 60 for the water-drawing plant is provided apart from the artificial floating island 10 for the submerged plant. The structure of the artificial floating island 10 for a submerged plant is the same as that described in the first embodiment.

  On the other hand, the structure of the artificial floating island 60 for a water extraction plant has a floating structure using a float 61, and a planting base 63 is provided in a frame 62. The artificial floating island 60 for the water extraction plant may be either a frame type or a frameless type, and the planting base 63 may be a chemical synthetic mat or a palm mat. On the planting base 63, for example, the water-drawing plant shown in FIG. 4 such as kishobu is planted via a planting pod or directly. The roots are sufficiently stretched through the planting base 20.

  In such a configuration, the wave height that strikes the artificial floating island 10 for a submerged plant is higher than the wave height at the growth limit of the submerged plant, based on the wave height that is set as the limit of the growth of the submerged plant that has been set in advance, or The response is divided according to the low.

  That is, when a wave higher than the limit wave height at which a submerged plant can grow, the artificial floating island 60 for a water extraction plant is installed in the direction in which the high wave hits. The artificial floating island 60 for the water-drawing plant may be moored separately by an anchor or the like so as not to be separated from the artificial floating island 10 for the submerged plant by a predetermined distance or more.

  In addition, when the wave that strikes the artificial floating island 10 for the submerged plant is lower than the wave height of the submerged plant growth limit, the artificial floating island 60 for the drained plant is placed in the direction of the wave of the maximum wave height of the wave to be struck. What is necessary is just to provide.

  The wave height of the growth limit of a submerged plant may be set to 20 cm, for example, as a growth limit generally for growing a submerged plant. Furthermore, in more detail, you may decide the wave height of the growth limit concerning every submerged plant. At present, the average wave height indicating the growth limit of a submerged plant is set to 20 cm, the wave higher than the set wave height is set to 20 cm or more, and the wave lower than the set wave height is set to less than 20 cm.

  In addition, the height of the wave that strikes may be based on actual measurements at the site. For example, the wave height for each direction may be measured with a meter. Or, for each direction, for example, calculated from the annual wind direction, wind speed, and blowing distance, and whether the wave height is higher or lower than the wave height of the submerged plant growth limit, the artificial floating island for water extraction plants as a wave-dissipating function The installation direction of 60 may be determined.

  In addition, by providing an artificial floating island 60 for the extraction plant near the artificial floating island 10 for the submerged plant, the presence of the floating island for the extraction plant suppresses the transmission of light below the surface of the water (light-shielding effect), thereby reducing the generation of phytoplankton. The ability to prevent water purification can increase initial transparency and increase the initial growth of submerged plants.

  In such a configuration, even if the artificial floating island 10 for a submerged plant is installed in a water area where the influence of the wave wind is large, the artificial floating island 60 for the submerged plant directly receives the wave wind and the influence of the wave on the artificial floating island 10 for the submerged plant is reduced. Can be suppressed. In particular, the roots that extend into the water of the water extraction plant suppress waves on the surface layer side of the water, reducing the influence of the wave-dissipating effect on the planting base 20 of the submerged plant, and promoting the overgrowth of the submerged plant.

  For example, it functions particularly effectively in water areas such as the Gulf that are greatly affected by wind waves. By arranging the artificial floating island 60 for the water-drawn plant so as to surround the artificial floating island 10 for the submerged plant under the situation where the wind waves are rushing toward the land, the influence of the wind wave can be reduced.

  In addition, an artificial floating island 60 for water extraction plants, which is installed on the artificial floating island 10 for submerged plants, is shielded from light, nutrients are taken in, water is purified by microbial communities attached to the roots that extend into the water, and birds rest and It has a multi-functional action different from the artificial floating island 10 for submerged plants, such as a nesting place. Therefore, by arranging the artificial floating island 10 for submerged plants and the artificial floating island 60 for water extraction plants having different functions and combining the two floating islands, effective water purification and creation of an ecosystem can be performed.

  That is, by disposing the conventional artificial floating island 60 for water extraction plants around the artificial floating island 10 for submerged plants, it is possible to have higher water quality purification ability than the conventional floating island. For example, the light-shielding effect of the extraction plant growing on the artificial floating island 60 for the extraction plant effectively suppresses the growth of phytoplankton from the beginning of installation and improves the transparency of the water. The installation possibility of the artificial floating island 10 for plants can be expanded.

  In addition, by arranging floating islands for water-drawn plants around the artificial floating island 10 for submerged plants, the float 40 of the artificial floating island 10 for submerged plants is not easily noticeable, and additional values such as improving the landscape are also generated. In particular, in the case of a water area where the direction of the wind wave is not constant, it is required to completely surround the artificial floating island 10 for submerged plants with the artificial floating island 60 for water extraction plants. In such a case, the effect is great.

  That is, in the artificial floating island 10 for a submerged plant, the planting base 20 is always submerged together with the submerged plant, so that the float 40 is only floating on the water surface. If there is a floating island in a state where a plant grows, it is preferable that an unpleasant situation that only the float 40 is floating on the surface of the water is hidden and the landscape is improved.

  So far, a structure of a vegetation base or a floating island in which water-drawn plants, floating leaf plants, and submerged plant zones are continuously provided has been proposed. However, in water purification target water areas with low transparency, submerged plants can only grow at shallow depths, and in such a configuration, submerged plants cannot grow against the competition of water-blowing and floating leaf plants. Such a structure is not preferred. As shown in FIG. 5, it is desirable to have separate floating islands or a structure such as providing a threshold.

  Moreover, in the place where the influence which a wind wave etc. has on the planting base 20 is large, in addition to the wave-dissipating structure, a wall for wave-dissipation of a certain height around the planting base 20 of the submerged plant artificial floating island 10 is provided. The structure to provide may be sufficient. Alternatively, a structure in which a structure in which protozoa such as adherent microorganisms and rotifers can inhabit is added to a plastic fibrous string-like carrier is disposed in the adjacent area around the artificial floating island 10 for submerged plants, and the wave-dissipating effect is obtained. You may make it secure. In such a configuration, it is possible to enjoy the water purification effect of the string-like carrier.

  In the above description, the case where the artificial floating island 60 for the water extraction plant is provided separately when the artificial floating island 10 for the submerged plant is installed in a place where the influence of the wind wave is strong is described. When the artificial floating island 10 for a submerged plant is provided on the water surface, the artificial floating island 60 for a submerged plant may be juxtaposed with the artificial floating island 10 for a submerged plant. For example, the floats may be connected to each other and connected adjacently. In such a configuration, the function of the artificial floating island 60 for a water-drawing plant is to further prevent the generation of phytoplankton by the light-shielding effect and promote the growth of submerged plants as described above. Of course, in such a case, the submerged plant artificial floating island 10 and the extraction plant artificial floating island 60 may be separated from each other within a range in which the light shielding effect and the removal effect of nutrients and the like are obtained.

(Embodiment 3)
In the present embodiment, a method for restoring a submerged plant community according to the installation target water area of the submerged plant artificial floating island 10 using the configuration of the submerged plant artificial floating island 10 described in the first embodiment will be described.

  In such a method, basically, as the growth limit water depth of the light transmittance at which the submerged plant can grow becomes deeper as the submerged plant grows, the submerged plant for artificial floating island 10 where the submerged plant is planted is used. A method of gradually deepening the planting base 20 in the range of the growth limit water depth is adopted.

  FIG. 7 (a) describes such a technique. As an installation target water area, a reservoir pond A is assumed, an artificial floating island 10 for a submerged plant is installed in the reservoir pond A, and a submerged plant community is installed in the water area. The case of forming will be described as an example. In such a reservoir pond A, it is assumed that the water is so polluted that it is impossible to grow a submerged plant.

  As shown in FIG. 7 (a), first, the height of the planting base 20 is initially set at a water depth in a range where the light transmittance with respect to the water surface is 20% or more by the photon meter. For example, if the transparency is about 1 m, the water depth is about 20 to 30 cm. Install at such depth to promote the growth of submerged plants. At the beginning of installation, in a water area where water pollution has progressed and the submerged plant has been substantially extinct, the transparency of water is poor, and unless the planting base 20 is set shallow, the light transmittance does not reach 20% or more.

  In order to carry out more reliably, it is good to carry out by selecting the water depth which becomes 50% or more of the light of a water surface by the measurement of a photon meter before germination or when the stem height of a seedling is 10 cm or less.

  When a submerged plant grows on the planting base 20 in such a state, the transparency of water is gradually improved by the grown submerged plant. As submerged plants grow, their water purification improves transparency and improves light transmission. As a result, the growth limit water depth at which the submerged plant can grow is deepened, and the water depth at which the planting base 20 can be installed can be deepened accordingly.

  Thus, the installation water depth of the planting base 20 is deepened by adjusting the angles 33 and 34 according to the growth of the submerged plant. By adjusting the installation water depth of the planting base 20, the height of the stem of the submerged plant community is increased and the plant grows. For example, when the stem height is larger than 10 cm due to growth, the water depth is increased in a range where the transmittance of light on the water surface is 20% or more. For example, it is installed at a water depth where the light transmittance is 20%.

  In this way, the submerged plant grows further, the water quality of the target water area is purified, and the transparency of the water is gradually improved. If the installation water depth of the planting base 20 is deepened according to it, the light which enables the submerged plant to grow can be transmitted to the bottom of the lake in the target water area. Such a change in water depth may be achieved by, for example, lowering the water depth of the planting base 20 once a year to a water depth at which the photon is 20% in the summer when the water is most turbid.

  In this state, the seeds or spores of the submerged plant planted on the planting base 20 for the submerged plant scatter to the bottom of the water. When seeds and spores are supplied to the surrounding water area from the overgrown submerged plant community in the submerged plant floating island 10, the submerged plant community is gradually formed from the bottom of the submerged plant artificial floating island 10. Become. The restoration of ecosystem functions in submerged areas will accelerate water purification, eventually purifying the entire water area and ensuring that submerged plant communities are also formed at the bottom of the water. Such a state is schematically shown in FIG.

  When the submerged plant is reliably grown on the bottom of the water based on the scattered seeds or spores, as shown in FIG. 7C, for example, the artificial floating island 10 for the submerged plant may be removed. . Removal is also preferable from the viewpoint of the surrounding landscape.

  When filling the planting base 20 of the artificial floating island 10 for submerged plants with the earth and sand collected from the bottom of the target water area, the seeds buried in the earth and sand have germinated and previously existed in the target water area. The submerged plant grows and the submerged plant community can be restored. In addition, if there are few seeds etc. buried, germinate and grow in advance from the sediment collected from the bottom of the water, increase the seedlings, and then use the seedlings to inhabit the waters. It is possible to restore the existing submerged plant community to the water area.

  When installing floating islands for submerged plants in water areas where water pollution has progressed for purification purposes, the installation area of floating islands shall be 20% or more of the water area. Generally, when 20% of submerged plant communities in the coastal areas of lakes and marshes are restored, it is said that the transparency is about 2m in water areas with transparency of less than 1m, which has a considerable degree of transparency improvement effect. For example, the water depth at which a transmittance of 20% or more is ensured is 0.7 m to 1.4 m, and the submerged plant community can be restored to the bottom of the water depth of 1.4 m.

(Embodiment 4)
In the present embodiment, using the artificial floating island 10 for a submerged plant described in the first embodiment, submergence is performed in a water area where the density and number of types of zooplankton are very small or only small zooplankton communities exist. A method of enhancing the water purification function by the plant artificial floating island 10 will be described.

  As described in the above embodiment, the submerged plant is appropriately grown using the planting base 20 of the artificial floating island 10 for a submerged plant. After the submerged plant community has grown in this way, as shown in FIG. 8, zooplankton such as Daphnia magna, Okame Daphnia, Ken Daphnia, Elephant Daphnia, etc., copepods, rotifers, etc. are introduced.

  The zooplankton to be introduced may be of a single type, but it is desirable to mix and introduce these zooplankton communities because they are effective against various phytoplankton. The zooplankton can be collected by culturing, or in ponds and swamps where zooplankton communities are abundant in the target water basin, collect them by collecting them with a net for zooplankton. Can do.

  In particular, in the present invention, as described in the first embodiment, since the net 51 is stretched on the submerged portion of the planting base 20 of the submerged artificial floating island 10, such zooplankton is used as a bait. Fish etc. will not enter. Therefore, the introduced zooplankton can inhabit and increase in the submerged plant of the submerged plant artificial floating island 10.

  Among Daphnia magna (0.5 mm), Niseko (0.2-0.5 mm), Marsh (0.5 mm) and other small Daphnia, butterfly (0.6- 2 mm), Daphnia (daphnia: 0.7 to 3 mm), and giant sea bream (adult body length is 2 mm), etc., eat more phytoplankton than small daphnia and have high water purification efficiency. Are known.

  If there is no hideout where the submerged plant is prosperous, such a large Daphnia will be noticeably easily preyed by fish because the adult body length will be as large as 1 to 2 mm. However, in the artificial floating island 10 for a submerged plant of the present invention, the net 51 prevents the fish from entering, and large daphnia is not preyed. Actually, there are few large daphnias in water areas with few aquatic plants such as submerged plants, and it can be said that the effect of introducing daphnia from the outside is great.

  Daphnia is known to be generated from eggs when the environmental conditions are improved by submerging durable eggs (dormant eggs) on the bottom of the lake due to changes in environmental conditions such as a drop in water temperature and a deterioration in the feeding environment. Yes. Taking advantage of this phenomenon, the bottom of the target water area is first collected, and daphnia are generated from the endangered eggs of zooplankton sleeping on the bottom of the lake under the condition of no fish. By introducing it into a submerged plant community that proliferated in the artificial floating island 10 for submerged plants, it is possible to prevent the introduction of species from other water areas and to purify it using the conventional zooplankton community.

  FIG. 9 (a) shows the result of an experiment in which mud collected from the bottom of the water is introduced into a culture of the blue-green algae microkistis that is the main species of the formation of blue sea bream. The experiment was performed at 28 ° C. and a light intensity of 2000 lux while changing the light and dark conditions every 12 hours and slowly stirring. A zooplankton community emerged from the bottom of the water, and 14 days later, the phytoplankton was preyed by the zooplankton. As a result, it was confirmed that the concentration of chlorophyll a, which is an indicator of the existing amount of phytoplankton, was greatly reduced and the water became transparent.

  It can be seen that the increase in phytoplankton related to water transparency is affected by the presence or absence of zooplankton. By the way, the case where there is no zooplankton is shown in white, and the case where there is zooplankton is shown in black. Moreover, it carried out using 3 types of each test body, and the result was shown by (triangle | delta), (square), and (circle).

  In addition, the number of individuals and types of zooplankton is small, the water of the actual pond with a large amount of blue-tailed sea cucumber (mainly the blue-green algae Microkistis) is collected, the pond mud is thrown in, and no fish exist. The experiment was conducted. Culturing was carried out for 18 days under conversion of light and dark conditions at 25 ° C. and 2000 lux for 12 hours. Little zooplankton occurred and phytoplankton did not decrease. However, as shown in Fig. 9 (b), 18 days later, zooplankton communities including rotifers and daphnids were collected from the ponds rich in zooplankton by the plankton net, and the ako disappeared as soon as it was introduced. Transparency was also improved and chlorophyll a concentration was significantly reduced.

  As a result of this experiment, even in a water area with a small amount of zooplankton community, if a durable egg is present on the bottom of the water, the cultured zooplankton community is put into a regenerated submerged plant community and inhabited. It can be seen that the water purification effect is promoted and improved.

  In addition, even when there is no durable egg, as shown in FIG. 9 (b), an artificial floating island for a submerged plant that has been collected from a water area where culture or nearby zooplankton is abundant has been taken. 10 can be increased in a submerged plant community, and phytoplankton can be effectively removed.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  The present invention can be effectively used in a field related to an artificial floating island for a submerged plant in which the submerged plant of the present invention is artificially planted.

It is a side view which shows typically the Example of the artificial floating island for submerged plants of one embodiment of this invention. (A) is a perspective view which shows the structure of the float used in this invention, and its flame | frame, (b) is a perspective view which shows the condition which provided the planting base in the flame | frame. (A), (b) is explanatory drawing which shows the condition which performs water level adjustment. It is explanatory drawing which showed and listed the specific example of aquatic plants, such as a submerged plant. It is explanatory drawing which shows the structure which provided the artificial floating island for water extraction plants in the windward side of the artificial floating island for submerged plants. It is explanatory drawing which shows a mode that the artificial floating island for submerged plants and the artificial floating island for water extraction plants were arrange | positioned along the shore. (A), (b), (c) is explanatory drawing which shows the procedure of the restoration method of a submerged plant community using the artificial floating island for submerged plants. It is explanatory drawing which introduces zooplankton to the artificial floating island for submerged plants, and promotes water quality improvement. (A) is explanatory drawing which shows the mode of water quality improvement by the presence or absence of zooplankton, (b) is explanatory drawing which shows that water quality improvement can be aimed at by throwing in zooplankton.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Artificial floating island for submerged plants 20 Planting base 20a Porous member 21 Planting pod 30 Support body 31 Frame 31a Angle 32 Sheet 32a Blue sheet 33 Angle 34 Angle 35 Bolt 40 Float 51 Net 52 Net 60 Artificial floating island 61 62 Frame 63 Planting base A Reservoir

Claims (20)

An artificial floating island for submerged plants having a planting base for planting submerged plants,
An artificial floating island for a submerged plant characterized in that the submerged portion of the planting base is surrounded by a net so that animals that feed on the submerged plant do not enter. In the artificial floating island for submerged plants according to claim 1,
The artificial floating island for a submerged plant, wherein the net has a mesh size of 1 mm or more and 100 mm or less. An artificial floating island for submerged plants having a planting base for planting submerged plants,
An artificial floating island for a submerged plant characterized in that the upper part of the planting base is surrounded by a net so that birds that feed on the submerged plant do not enter. In the artificial floating island for submerged plants according to claim 3,
The artificial floating island for a submerged plant, wherein the net has a mesh size of 5 mm or more and 200 mm or less. An artificial floating island for submerged plants having a planting base for planting submerged plants,
Enclose the submerged portion of the planting base with a net so that animals that feed on the submerged plant do not enter, and surround the upper part of the planting base with a net so that no bird disturbing the submerged plant can enter An artificial floating island for submerged plants. An artificial floating island for submerged plants having a planting base for planting submerged plants,
The submerged portion of the planting base is surrounded by a net so that fish that feed on zooplankton that uses the submerged plant as a place of life is not inserted, and the upper part of the planting base is a bird that disturbs the submerged plant An artificial floating island for submerged plants, which is surrounded by a net so that it cannot enter. An artificial floating island for submerged plants having a planting base for submerged plants for planting submerged plants,
The artificial floating island for submerged plants, wherein the planting base for submerged plants is surrounded by a wave-dissipating function. In the artificial floating island for submerged plants according to claim 7,
When the wave height to the artificial floating island for the submerged plant is higher than the wave height at the growth limit of the submerged plant, the wave-dissipating function is provided in a direction in which a wave higher than the wave height at the growth limit of the submerged plant comes. An artificial floating island for submerged plants. In the artificial floating island for submerged plants according to claim 7,
When the wave height to the artificial floating island for the submerged plant is lower than the wave height at the growth limit of the submerged plant, the wave-dissipating function has the highest wave height among the wave heights to the artificial floating island for the submerged plant. An artificial floating island for submerged plants, characterized by being provided in the direction. In the artificial floating island for a submerged plant according to any one of claims 7 to 9,
The artificial wave floating island for a submerged plant, wherein the wave-dissipating functioning material is an artificial floating island for a drained plant planted on a planting base. An artificial floating island for submerged plants having a planting base for submerged plants for planting submerged plants,
The artificial floating island for a submerged plant, wherein the planting base for a submerged plant is juxtaposed with an artificial floating island for a submerged plant that is planted on the planting base. An artificial floating island for submerged plants having a planting base for submerged plants for planting submerged plants,
An artificial floating island for a submerged plant, wherein the submerged plant is planted on a planting material such as sponge, rock wool, slag wool, etc., and the planting material planted with the submerged plant is placed in the planting base for the submerged plant. An artificial floating island for submerged plants having a planting base for submerged plants for planting submerged plants,
An artificial floating island for a submerged plant, wherein the submerged plant is a germinated seed of a submerged plant contained in earth and sand collected from the bottom of a water area where the planting base for the submerged plant is installed. As the growth limit water depth of the light transmittance capable of growing the submerged plant becomes deeper as the submerged plant grows, the planting base of the artificial floating island for submerged plant in which the submerged plant is planted is within the range of the limit water depth. Deepening steps,
Scattering seeds or spores of submerged plants planted on the planting base to the bottom of the water;
A method for forming a submerged plant community using an artificial floating island for a submerged plant, comprising the step of growing a submerged plant on the bottom of the water based on the scattered seeds or spores. In the formation method of a submerged plant community using the artificial floating island for submerged plants according to claim 14,
The method for forming a submerged plant group using the submerged plant artificial floating island, wherein the submerged plant artificial floating island is removed when the submerged plant takes root on the bottom of the water. In the formation method of a submerged plant group using the artificial floating island for submerged plants according to claim 14 or 15,
The method for forming a submerged plant group using an artificial floating island for submerged plants, characterized in that the limit water depth at which the submerged plant can grow is a water depth of 20% or more. In the formation method of the submerged plant group using the artificial floating island for submerged plants of any one of Claims 14-16,
The submerged plant is an artificial floating island for submerged plants characterized by germinating submerged plant seeds contained in earth and sand collected from the bottom of the water area where the planting base for the submerged plant is installed. Formation method of submerged plant group. A method of purifying water using an artificial floating island for submerged plants planted on a planting base,
A water purification method using an artificial floating island for submerged plants, characterized in that zooplankton is brought from outside into a submerged plant planted on the planting base of the artificial floating island for submerged plants. In the water purification method using the artificial floating island for submerged plants according to claim 18,
The zooplankton is a water purification method using an artificial floating island for submerged plants, wherein the zooplankton is generated using bottom mud collected from the bottom of the target water area where the artificial floating island for submerged plants is installed. In the water purification method using the artificial floating island for a submerged plant according to claim 18 or 19,
Water quality using an artificial floating island for a submerged plant, wherein the submerged plant is a germinated seed of a submerged plant contained in earth and sand collected from the bottom of the water area where the artificial floating island for the submerged plant is installed. Purification method.

Images