JP2005220610A - Continuous flow type slit sand control dam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a slit sand control dam suitable for environmental preservation, including flood control, irrigation and the protection of an ecosystem. <P>SOLUTION: This slit sand control dam has a slit for discharging an avalanche of sand and stone flowing in by exceeding a planned high water flow quantity on the downstream side in a flood. The continuous flow type slit sand control dam has a cascade construction with an overflow to part of the slit as a first stage overflow dam bank top, on the slit downstream side of the slit sand control dam. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a slit sabo dam that can ensure the planned high water flow rate and safety on the downstream side of the dam by appropriately flowing a debris flow from the slit at the flood peak when the debris flow rate flowing from the basin increases. The present invention relates to a continuous-flow slit sabo dam that has cascade work to prevent scouring of the downstream river bed by water and debris flow, and is suitable not only for flood control and water use but also for environmental conservation and ecosystem protection.

Many sabo dams have been installed from the viewpoint of flood control of small rivers. However, the debris flow that has accumulated in only one flood often fails to perform its original function. Had the disadvantage of requiring significant costs. The inventor has invented and proposed a slit sabo dam as a sabo dam that can improve such a drawback (Patent Document 1).
JP 2002-317429 A (Patent Brother 3493318)

  This slit sabo dam prevents the dam from being filled with debris flow by discharging the debris flow that flows in excess of the planned high water flow rate on the downstream side of the dam during floods. Since the stored debris flow flows down together with the inflow debris flow, the river bed on the upstream side of the dam can always be at a height corresponding to the altitude of the top of the slit overflow.

  However, it was found that the slit sabo dam also has the disadvantage that it becomes difficult to secure the planned amount of water and changes the environment because the riverbed downstream of the dam is scoured and the shape of the river changes. Therefore, as a result of intensive studies to improve such drawbacks, the present inventors have established a floor consolidation cascade on the downstream side of the slit sabo dam, which is suitable not only for environmental conservation but also for flood control and water use. In addition, the present inventors have found that it is easy to secure a fishway and can be suitable for ecosystem conservation, and have reached the present invention.

Accordingly, a first object of the present invention is to provide a slit sabo dam suitable for flood control / water use and environmental conservation.
A second object of the present invention is to provide a slit sabo dam suitable for environmental conservation including ecosystem protection.

  The above objects of the present invention are to provide a slit sabo dam having a slit portion for discharging a debris flow that flows in excess of a planned high water flow rate on the downstream side during a flood, and a slit sabo dam downstream of the slit sabo dam. This was achieved by a continuous-flow type slit sabo dam characterized by having a cascade work with the top of the slit as the first stage overflow dam.

  The continuous-flow slit sabo dam of the present invention has a slit so that the dam is not filled with debris flow due to flooding, and the river bed upstream of the dam can always be made to have a height according to the elevation of the top of the slit overflow. Suitable for flood control and water use. Furthermore, because it has a floor consolidation cascade, there is no scouring due to falling water or debris flow, making it suitable for environmental conservation. Furthermore, by providing the above-mentioned floor consolidation cascade work so that fish can go up, or by providing a separate floor consolidation cascade type fishway, it is possible to provide an ecosystem protection function.

EXAMPLES Hereinafter, although this invention is explained in full detail based on an Example, this invention is not limited by this.
FIG. 1 is a front view of a slit sabo dam used in the present invention, and FIG. 2 is a side view. In the figure, reference numeral (1) is the original riverbed, (2) is the foundation ground, (3) is the sleeve, (4) is the slit overflow part (cascade overflow bank top), (5) is the sediment riverbed It is.

FIG. 3 is a side view of the continuous-flow slit sabo dam according to the present invention in which three (three stages) cascades are arranged on the downstream side, and FIG. 4 is a plan view thereof. In the figure, the symbol (6) is the paragraph length, (7) is the cascade side wall, (8) and (8 ') are the water cushion parts, (9) is the deflector (floor dam), (10) is the paragraph height, (11) is the depth of the water cushion, (12) is the downstream grate, (13) is the downstream riverbed, (14) is the intake opening, (15) is the cutout for the fishway . R is the radius of curvature of the curved surface of the slope of the slope of the slope slope, θ ₁ is the slope angle of the slope of the paragraph, θ ₂ is the slope angle of climbing the deflector, and L is the horizontal bottom length of the water cushion. 5 and 6 are an AA sectional view and a BB sectional view in FIG. 3, respectively, in which B is a cascade width and B ′ is a notch width.

  In the continuous-flow slit sabo dam of the present invention, the river flow upstream and downstream of the slit overflow section (floor compaction weir) (4) becomes a continuous flow condition during the normal water, thus preserving the river environment. At the same time, it is possible to protect the ecosystem by guaranteeing the invasion of inhabiting fish. Since this sabo dam repeatedly stores and discharges inflow debris flows, the dam storage capacity can be reduced compared to traditional sabo dams with drainage holes, reducing construction costs. In addition, it is easy to maintain and manage. Moreover, the sabo dam of the present invention is effective in improving the flow of a river in which floor stop works are continuously installed into a continuous flow.

  In other words, traditional sabo dams with drainage holes that have been constructed in the past have accumulated most of the inflow debris flow and discharged the inflow water to prevent debris flow disasters. When the dam is reclaimed, the function of the sabo dam is lost. In addition, since the river flow is discontinuous, there is a problem from the viewpoint of river environment conservation and ecosystem protection, and the construction of a traditional sabo dam on the river where fish rises up, the continuous river flow is divided. There are many cases.

  In addition, slit sabo dams, which have been increasingly constructed in recent years, are characterized by the prevention of debris flow disasters and the reduction in the size of sabo dams, while simultaneously storing and discharging inflow debris flows during floods. Since this is a river structure mainly composed of flood control, there is a lack in terms of river environment conservation and ecosystem protection. In addition, these sabo dams need to be equipped with de-energization and floor protection works such as secondary dams, water hammering and floor protection.

  On the other hand, the continuous slit-type sabo dam of the present invention has a function of reducing the dam storage capacity by the floor consolidation cascade itself, and can realize a continuous river flow. Therefore, it is a river structure for flood control and water use that can guarantee river environment conservation and ecosystem protection.

  The width and height of the slit in the continuous-flow slit sabo dam of the present invention are determined so as to have a cross section that can safely flow down the planned high water flow rate of the downstream river in accordance with the river topography and flow conditions. , Slit overflow height is the height that protects the river bed from scouring and stabilizes the river channel. The width of the levee is determined according to the sabo standards. Furthermore, the number of cascade works connected to the cascade works with the slit overflow section (4) as the floor consolidation weir will be determined in consideration of the river topography, flow conditions, the invasion of habitat fish, the ecosystem, etc.

In the continuous flow type slit sabo dam according to the present invention, the floor compaction dam paragraph slope outlet has a curved surface with a radius of curvature R of 1/5 or more of the paragraph height, and the flowing water vein flows down the paragraph slope along the curved surface. This is preferable in order to make the current flow easier, and to make it easier for fish going up the paragraph slope. Also, the height of the paragraph between the top of the overflow and the bottom of the water cushion 8 should be about ₁ m to 1.3 m, and the inclination angle θ ₁ should be 45 ° to 60 ° so that fish can easily go up. Is preferable, and about 50 ° is particularly preferable.

The height difference between the overflow dam top and the top of the deflector (9) is preferably about 0.4 to 0.6 m. The design flow rate for effectively using the water in the water cushion portion (8) is about 1/20 to 1/5 of the planned high water flow rate, but the depth (deflector height) of the water cushion (11) is It is preferable to form a waterside environment in which inhabited fish are hardly attacked by birds as 0.3 to 0.5 m. The horizontal bottom floor length L of the water cushion portion (8) is preferably about 1.5 to 2.0 times the paragraph height (10), and the water cushion portion (8) is connected to the deflector (9). inclination angle theta ₂ of the creep-up slope is preferably set to 20 ° to 25 ° approximately. At the downstream end of the lowermost cascade, there will be a water cushion part with a protection floor block, gabion or shark bunker to prevent scouring of the downstream riverbed and to form a stagnant area for upstream fish Is preferred.

  The continuous-flow slit sabo dam of the present invention is generally made of a concrete structure. However, in areas where appropriate stone materials are available, a structure that can easily be adapted to the natural environment by using a machinite masonry or masonry structure. It can be a thing. Moreover, when constructing a cascade on a water-permeable ground (river bed), it is set as the paragraph length (6) and cascade man-hour which can ensure sufficient permeation path length.

When it is necessary to guarantee the fish going up at the time of the drought flow, it is necessary to put the fish going up to a part of the slope slope outlet (ie, the top of the slit overflow (4) or the deflector of the cascade (9)). A suitable cutout (15) is provided to provide a fishway. In this case, a side wall can be provided as appropriate at the boundary between the cascade and the fishway. The width B of the cascade is a width according to the width of the slit, and the height of the cascade side wall (7) is appropriately determined according to the river topography and the flow condition at the point.
In the case of water intake, a water intake opening (14) corresponding to the amount of water intake is provided in the cascade side wall (7) where the water cushion portion (8) is formed, or water is permeable to the upstream riverbed of the slit overflow dam. A reverse-gradient bar screen intake can be installed. These can be added together.
Each dimension of the cascade can be calculated according to the floor-fixed cascade type fishway described in JP-A-2002-317429.

  Since the continuous-flow slit sabo dam of the present invention has a slit, the dam is not filled with debris flow due to flooding, and the river bed on the upstream side of the dam can always be at a height according to the elevation of the top of the slit overflow. So it is suitable for flood control and water use. Furthermore, because it has a floor consolidation cascade, there is no scouring due to falling water or debris flow, making it suitable for environmental conservation. Furthermore, the above-mentioned floor consolidation cascade work can be provided so that fish can be run up, or by providing a separate floor consolidation cascade type fishway, it is possible to have an ecological protection function. Sabo dams are extremely useful.

It is a front view of the conventional slit sabo dam. It is sectional drawing of the slit sabo dam of FIG. It is a side view of the continuous-flow type slit sabo dam of the present invention in which three (three stages) cascades are arranged on the downstream side. FIG. 4 is a plan view corresponding to the side view of FIG. 3. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG.

Explanation of symbols

1 Prototype riverbed 2 Foundation ground 3 Sleeve 4 Slit overflow (cascade overflow levee)
5 Sedimentary riverbed 6 Paragraph length 7 Cascade side wall 8 Water cushion part 8 'Water cushion part 9 Deflector (floor consolidation weir)
10 Paragraph Height 11 Water Cushion Depth 12 Downstream Bed Protection 13 Downstream Original Riverbed 14 Intake Opening 15 Notch R Paragraph Slope Falling Corner Radius θ ₁ Paragraph Slope Inclination θ ₂ Deflector Uphill Slope Angle L Water cushion horizontal bottom length B Cascade width B 'Notch width

Claims (10)

A slit sabo dam having a slit part for discharging a debris flow that flows in excess of the planned high water flow rate on the downstream side in the event of a flood, and a first stage of the overflow overflow top part on the downstream side of the slit part of the slit sabo dam. A continuous-flow type slit sabo dam characterized by having a cascade work with the overflow weir crest. The continuous-flow type slit sabo dam according to claim 1, further comprising a cascade type fishway provided on the downstream side of at least a part of the slit so that the fish can go upstream beyond the slit sabo dam. The continuous-flow type slit sabo dam according to claim 1 or 2, having at least one water intake port at any location. The cascade work is provided in two or more stages, and the overflow weir crest of the second and subsequent cascade works is the overflow overflow of the deflector in the previous cascade work. A continuous-flow slit sabo dam. The continuous flow type slit sabo dam according to any one of claims 1 to 4, wherein a slit of the slit sabo dam is provided only in a central portion of the river width. The continuous-flow type slit sabo dam according to any one of claims 2 to 5, wherein the cascade type fishway is provided on the downstream side of one end of the slit. The continuous-flow type slit sabo dam according to claim 6, wherein the cascade type fishway has a side wall for separating the fishway from a cascade part other than the fishway. The continuous-flow type slit sabo dam according to claim 7, wherein a water intake is provided in the side wall. The continuous flow according to any one of claims 2 to 8, wherein an overflow top portion of the slit portion in a portion continuing to the fishway has a notch portion that is cut out so that the fishway water flow smoothly continues. Type slit sabo dam. The continuous river described in any one of Claims 1-9 which has a water cushion part using a protection floor block, a gabion, or a cocoon paddle which can prevent scouring in the downstream river bed of the lowest cascade work. Flow slit sabo dam.