JPH0561406B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a seawater exchange breakwater that exchanges seawater outside a port into a port.

(Prior Art) The Japanese coastline is roughly divided into three types: coastal areas facing the open sea, open bay areas, inland seas, and closed inner bays. In particular, open bay areas, inland seas, and closed inner bays have been extensively used since ancient times because their natural topography allows for calm natural conditions such as waves. It is widely known that most of the landfill sites, coastal factories, and ports are concentrated in these areas, and the problem of seawater pollution has become increasingly serious.

Currently, wastewater regulations have been implemented and seawater purification is gradually progressing, but the deterioration of the quality of stagnant water in closed water areas such as harbor areas is still considered a problem. Additionally, in the fisheries industry, with the establishment of a 200 nautical mile zone in recent years, fishing patterns have been changing from far-seas to offshore to coastal areas, and aquaculture cages are being installed within fishing ports. From this perspective as well, water quality conservation in closed waters within fishing ports is required.

There is a conventional seawater exchange breakwater 1 that exchanges seawater outside the port into the port in order to maintain water quality within the port.
As shown in FIG. 8, a breakwater main body 2 is provided so as to partition an outside port 3 and an inside port 4, and a flow passage 5 is provided in the lower part of this breakwater main body 2 so as to communicate between the outside port 3 and the inside port 4, We are trying to exchange seawater using wave power and other means. In addition, the conventional seawater exchange breakwater 1 shown in FIG. 9 has a bellmouth-shaped part 5A with a small loss on the outside port side 3 of the flow path 5, and a protruding part 5B with a large loss on the inside port side 4, so that inflow due to wave force We are trying to make a difference in the amount of output. In this way, the amount of water flowing into the port 4 will be improved on average, and the flow of seawater in the port 4 will be promoted. Next, in the conventional seawater exchange breakwater 1 shown in FIG. 10, a flutter valve 6 is provided at the outlet of the flow passage 5 on the port side 4, and when the flow is in, the valve 6 is opened by wave force to allow seawater to flow in, and when it is out, the valve 6 is opened by the wave force. The valve 6 is closed to prevent seawater from flowing out.
In this way, a unidirectional flow can always be expected toward the inside of the port 4, and the flow of seawater in the inside of the port 4 is promoted.

(Problems to be solved by the invention) However, in the structure shown in FIG.
When the wave height is small compared to the water depth, the waves outside the port 3 have a sinusoidal waveform, which causes a reciprocating flow with exactly the same flow rate in the flow path 5, resulting in a problem in which the inflow volume cannot be expected. In addition, in any of the types shown in FIGS. 8 to 10, pressure changes due to waves outside the port 3 propagate directly to the inside of the port 4 through the flow path 5, so new transmitted waves are generated inside the port 4. Breakwater 1
This has become a fatal problem in terms of its original purpose of extinction.

An object of the present invention is to provide a seawater exchange breakwater that can maintain the water quality of the harbor area while keeping the interior of the harbor calm.

(Means for solving the problems) The gist of the present invention for achieving the above object is as follows:
A breakwater main body is provided to separate the outside of the port from the inside of the port, and a water storage tank is provided at the top of the breakwater main body into which overflow water from overtopping waves from outside the port flows into the water storage tank. This consists in that a water conduit is formed with a height difference from the bottom of the water tank to the bottom of the port so that a pumping action is generated by overflow water and a jet flow is formed at the bottom of the port. .

(Function) In this way, overflow water 10, 10A, 10B due to overtopping waves 9 from outside the port 3 accumulates in the water storage tanks 11, 11A, 11B at the top of the breakwater main body 2, and due to the difference in appearance H, the overflow water 10, 10A, 10B due to the overtopping waves 9 from outside the port 3 accumulates in the water storage tanks 11, 11A, 11B at the bottom of the inside 4 of the port. At the same time, other overflow water flows into the water storage tanks 11, 11A, and 11B, and a pumping action occurs, so that the seawater in the water storage tanks 11, 11A, and 11B sequentially flows into the port without stagnation. It is ejected to the bottom side of 4.

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. In this example, outside the port 3 and inside the port 4
A breakwater main body 2 is provided on a bottom part 7 via a foundation part 8 so as to partition the breakwater. The upper part of the breakwater main body 2 has an upward opening for receiving overtopping waves 9 from outside the port 3.
A water storage tank 11 is provided to store overflow water 10. The breakwater main body 2 is provided with an L-shaped headrace 12 for draining overflow water 10 stored in a water storage tank 11 to the bottom 7 side of the harbor interior 4 with a water head difference H. The cross-sectional area of this headrace 12 is naturally smaller than the water storage tank 11, and since it is formed with a difference in height from the bottom of the water storage tank 11 to the bottom 7 side of the port interior 4, a stronger pumping action is exerted on the overflow water 10. As a result, the force of the jet flow from the water storage tank 11 becomes stronger, and the seawater in the port can be stirred efficiently.

Further, an inclined surface 13 is formed on the upper part of the breakwater main body 2 on the side outside the port 3 in order to maximize the amount of inflow of overflow water 10 due to overtopping waves 9.

Such a seawater exchange breakwater 1 uses the water head difference H generated in the water storage tank 11 to direct overflow water 10 into the harbor 4.
Since the wave pressure is not directly transmitted to the inside of the port 4, the waves transmitted inside the port can be reduced to zero. Also,
According to such a structure, a completely unidirectional flow from the outside of the port 3 to the inside of the port 4 is achieved, so that the flow of water within the port is promoted. Furthermore, by setting the height of the overflow crest 14 appropriate for the normal average incident wave height (approximately 1 m or less), steady seawater guidance can be expected.

According to such a structure, the amount of dissolved oxygen in the seawater increases due to disturbances such as breaking waves when overflow water flows into the water storage tank 11. Therefore, as shown in Fig. 3, overflow water 10A with a large amount of dissolved oxygen flows into the bottom 7 side of the port 4, creating an aerobic condition, and the aerobic decomposition of microorganisms in the bottom 7 causes the seawater to deteriorate. Self-purification becomes active.

Furthermore, in the summer, generally, as shown in Figure 4,
The temperature of the surface water is high and becomes the high temperature 15, and the temperature of the low water is low and becomes the low temperature part 16, so that so-called density stratification is formed, and there is almost no exchange of seawater in the vertical direction. However, in the structure of the present invention, the high temperature In order to store the surface water in the section 15 in the water storage tank 11 by overtopping waves, and to cause this to flow into the low-level water in the low-temperature section 16 of the harbor interior 4, the density stratification in the harbor interior 4 is destroyed.
Seawater exchange is promoted by the vertical convection 17 phenomenon.

FIGS. 5 and 6 show other embodiments of the present invention. In this embodiment, a conduit 18 is connected to the water conduit 12 of the breakwater main body 2 inside the port 4, and the water tank 1
The overflow water 10 accumulated in the port 1 is guided to the back of the port 4 by a water head difference H and drained.

In this way, it is possible to encourage the flow of seawater in the water area away from the breakwater main body 2 in the harbor 4 as shown in FIG.

FIG. 7 shows still another embodiment of the present invention. In this embodiment, if the tidal difference in the target water area is large, waves may not exceed the overflow crest 14A at low tide. ，
11B are provided on the top and bottom of the breakwater main body 2, and correspondingly, headrace channels 12A and 12B are also provided, respectively.

In this way, the effects of the present invention can be achieved even in waters with large tidal differences.

Note that the number of water tanks is not limited to two, and an appropriate number can be provided depending on the tidal difference.

(Effects of the Invention) The present invention has the following effects by having the above configuration.

By installing the water tank at the top of the breakwater main body, the overtopping water in the tank can be allowed to flow quietly into the port due to the water head difference, making it possible to improve the water quality of the water area within the port while keeping the port calm. Out.

By installing the water tank at the top of the breakwater body, overflow water with a high amount of dissolved oxygen flows into the tank due to disturbances such as breaking waves, and this is ejected to the bottom of the port, which activates the self-cleaning action of seawater. can be converted into Furthermore, high-temperature surface overtopping waves are constantly stored and flowed into the bottom of the port, thereby promoting seawater exchange.

By forming the headrace channel with a height difference from the bottom of the water tank to the bottom of the port, the overflow water exerts a strong pumping action, increasing the force of the jet flow from the water tank and stirring the seawater in the port. Can be done efficiently.

By installing the water tank at the top of the embankment body and forming the headrace channel with a difference in height from the bottom of the water tank to the bottom of the port, the pumping action of overflow water allows the seawater in the tank to flow sequentially into the port without stagnation. Squirts on the bottom.

[Brief explanation of the drawing]

1 and 2 are a cross-sectional view and a plan view of an embodiment of a breakwater according to the present invention, FIG. 3 is an explanatory diagram showing the state of supply of dissolved oxygen to the seabed by the breakwater of this embodiment, and FIG. The figure is an explanatory diagram showing the seawater convection phenomenon in summer due to the breakwater of this embodiment, Figures 5 and 6 are cross-sectional views and plan views of other embodiments of the present invention, and Figure 7 is an implementation of the present invention. Example cross-sectional views, FIGS. 8 to 10 are cross-sectional views showing three examples of conventional breakwaters. 1... Seawater exchange breakwater, 2... Breakwater main body, 3
...Outside the port, 4...Inside the port, 7...Bottom, 9...Overtopping waves, 10,10A,10B...Overflowing water, 11,1
1A, 11B...Water tank, 12, 12A, 12B
... Headrace, 13 ... Inclined surface, 14, 14A, 1
4B...Top of overflow.

Claims (1)

[Claims] 1 A breakwater main body installed to separate the outside of the port from the inside of the port, with a water storage tank provided at the top of the breakwater main body into which overflow water from overtopping waves from outside the port flows into the water storage tank. A water conduit is formed with a height difference from the bottom of the water tank to the bottom of the port so that the overflow water causes a pumping action and forms a jet flow at the bottom of the port. Features a seawater exchange breakwater.