Patent ID: 12188193

DETAILED DESCRIPTION

(Prevention of River Disasters)

Although an entire water area Lr of a river is originally dominated by flow energy due to gravity in a river flow, it is possible to generate violate tide in an estuarine basin Lt of the river by constructing “sea hollow (UTSURO)” of surrounding an estuary sea area with a levee body structure8as illustrated inFIG.2and opening a water area26inside “sea hollow (UTSURO)” in the estuarine basin water area of the river with an upstream migration water channel19.

Regardless of how violent tide is, there are no tidal flows that flow in land areas, all the tidal flows are flows below a seawater surface, and there are no floods in tidal rivers comparable to the flow amounts of the rivers.

An estuary water area of a river conventionally dominated by flow energy due to gravity becomes a river water area dominated by ebb and flow energy, and a riverbed in an estuary water area Lt1of the river is scoured, by increasing the scale of “sea hollow (UTSURO)” and generating tide comparable to the flow amount of the river.

Although the scale of “sea hollow (UTSURO)” depends on Equation (1) above, the water channel is narrowed, and a tractive force is secured in accordance with the natural flow amount of the river in a case in which it is not possible to prepare a sufficient area due to conditions of terrains, water depths, and the like.

Furthermore, it is possible to generate violent tide in the main stream of the river by surrounding and closing an estuary sea area of an old river channel, a diversion channel, a branch river, or the like in the estuarine basin water area with the levee body structure8as inFIG.5depending on the terrain, using the diversion channel as an upstream migration water channel19, and opening it at the upstream of the main stream.

A leading end riverbed is constantly scoured by a violent vortex flow with leading ends Lv1and Lv2of the upstream migration water channel entrance13used as turnaround points of the water flow.

If it is assumed that the current riverbed4of the river is a stable slope, the riverbed is gradually scoured by this technique, and the riverbed is then naturally lowered to the line12inFIG.1.

Further, the riverbed14is scoured at the leading end Lv2by a vortex flow by extending an overflow levee9like13toward the upstream while holding the tide in the Lv1section of the upstream migration water channel entrance, the riverbed14is further lowered to the line of the riverbed15due to the stable slope of the natural flow, and the flood discharge section is further increased.

In this manner, the water area extension Ln dominated by flow energy due to gravity in the upstream part of the river becomes (Ln=Lr−Lt), the extension length of the river dominated by flow energy in the river becomes short, the energy slope in the river is enhanced, riverbed scouring advances, and flood discharge ability is enhanced.

Furthermore, in a case in which the ebb and flow energy is insufficient due to the extension of the system described above, deposition of sediments in the water area26inside “sea hollow (UTSURO)”, and the like in the future, “sea hollow (UTSURO)”33will be enlarged.

Moreover, in order deeply dig the riverbed in the section of the upstream part Ln dominated by flow energy due to gravity and to enhance flood discharge ability, the water channel in upstream and intermediate stream water areas is narrowed, the tractive force is enhanced, the riverbed is lowered, and the flood discharge section in the upstream part of the river is further increased.

According to this technique, separation levees are constructed such that low separation levees B longitudinally continue in a river reservation mainly using the riverbed mud and the like as illustrated inFIG.3, and in a case of a river with a wide width, a plurality of separation levees like B1, B2, B3, . . . are provided, movable dams G1and G2are placed at both upstream and downstream ends, and G3, . . . are further placed toward the upstream, the water channel is narrowed by operations of the upstream and downstream movable dams, the tractive force is enhanced, the riverbed is deeply scoured, and these operations are repeated, such that it is possible to deepen each water channel.

Moreover, water is retained in the water channels on the sides, the levee tops of the separation levees on the sides in the upstream part are lowered to allow overflowing beyond the separation levees, the entire separation levee bodies are scoured together, and the sediments in the river channel are caused to flow out.

These operations are alternately repeated to increase the flood discharge section of the river.

As an example of the above operations, if scouring is performed from the downstream part inFIG.3-3, and the flood discharge ability is enhanced, then the entire ground serves as a super levee, and repeated river disasters are prevented.

There is a concern of a water level decrease of groundwater or underground water with the lowering of the riverbed described above, and it is essential to place preservation water channels31on both sides of the river.

(Protection from Tsunami and Storm Surge)

Although storm surge waves are typically not broken, if tsunami or storm surge waves are caused to break, they release enormous energy, the wave heights increase, and water invasion to land areas occurs, which leads to expansion of damage.

The maximum wave height of offing tsunami waves is about 10 m, and the offing tsunami waves are waves that have long wave lengths and are likely to be diffracted and reflected.

The surrounded coastal land area is to be protected from tsunami and storm surge by sharing the levee body8of the tide generation apparatus based on “sea hollow (UTSURO)” described above in claim1.

Waves are not broken and are reflected as overlapping waves by the front water depth at the breakwater being set to be equal to or greater than about a double the wave height.

Tsunami is reflected by maintaining the front water depth at the levee body8constituting “sea hollow (UTSURO)” to be equal to or greater than about a double the wave height of tsunami.

Therefore, a tsunami breakwater with a reflection structure in which the levee bodies of “sea hollow (UTSURO)” placed in the coastal sea area as described in claim1are continued is constructed thereby to prevent tsunami and storm surge in the coastal sea area and prevent repeated tsunami and storm surge.

(Measures for Upstream Migration Tsunami and Storm Surge of River and Estuary Flood)

In order to prevent damage due to upstream migration tsunami and storm surge of a river and further an estuary flood, the levee body constituting “sea hollow (UTSURO)” placed in the river estuary coastal sea area as in claim1and claim2is shared to achieve rolling-in toward the upstream of the estuary, further extension toward the upstream of the river is achieved, and the water channel entrance is opened in the upstream part of the river.

The crown height of the levee body constituting “sea hollow (UTSURO)” is set to be equal to or less than the seawall height on both sides of the river in the river to allow the peak of estuary flood, storm surge, or tsunami to cause overflow, and peak-cut of the estuary flood, storm surge, or tsunami is achieved.

At the time of ebb tide during the flood, storm surge, or tsunami described above, such energy plays an important role in scouring of the estuary and prevent repeated estuary flood, storm surge, and tsunami disasters as illustrated in the right diagram in each of [FIG.2-4] and [FIG.2-5].

Furthermore, in order to secure the flood discharge capacity at the estuary and to limit and restrict the upstream migration tsunami flowing into the estuary, the width of the opening into which tsunami and storm surge flows is set to be the bare minimum, and the tsunami and storm surge invasion preventing levees28are extended on both sides toward the offing.

(Transport and Processing of Sediments)

The above techniques in claim1, claim2, claim3, claim4, and claim5require excavation and transport of an unimaginably huge amount of sediments.

Such scoured sediments are safely transported as mud water at the time of flood or the like by several tens of kilometers, several hundreds of kilometers, or sometimes several thousands of kilometers to the estuary sea area, by enhancing a river tractive force and effectively utilizing a natural force on the basis of the techniques in claim1, claim2, claim3, claim4, and claim5using a natural force without using transport equipment such as a truck, a ship, or a train,26“sea hollow (UTSURO)” B (the water area29surrounded by a multiple-gap levee body28is a quiet water area), the multiple-gap levee body being a rubble mound levee, a concrete block levee, a slit caisson levee and the like, or a mixed levee thereof. Mud water that has reached the estuary is transmitted through the multiple-gap levee body due to a natural ebb and flow action, enters “sea hollow (UTSURO) B where the sea area29is a quiet sea area, mud is settled in six hours of tide and flow, and water is cleaned and flows out to the sea area at the time of ebb tide.

Furthermore, organic substances are subjected to contact oxidation and are further cleaned by microorganisms when entering and exiting the levee body.

Therefore, provided is a method of an environment-friendly technique of preventing repeated river disasters as a system essential for completing the techniques of claim1, claim2, claim3, claim4, and claim5described above.

When the techniques for preventing repeated (tsunami, storm surge, and river) disasters with a natural force as described above are performed, it is always necessary to perform hem from the estuary part in a planned manner.

REFERENCE SIGNS LIST

1Height of river levee2Ground height of riverbed of river in current situation3Surface water at normal time4Riverbed of river in current situation5Maximum flood level6High water level of ebb and flow7Low water level of ebb and flow8Tsunami breakwater9Levee body constituting upstream migration channel, overflow levee for peak-cut at time of attack of river upstream migration tsunami, storm surge, and estuary flood10Vertical section of estuary riverbed scoured by tide generation apparatus “hollow sea (UTSURO)”11Direction of lowering of riverbed of scoured riverbed at estuary due to stable slope of river12Scoured riverbed with stable slope of1113Extension direction of levee body constituting upstream migration channel14Leading end scouring by vortex flow at turnaround of upstream migration channel entrance15Vertical section of riverbed scouring with decrease in stable slope in case of extension toward upstream of levee body constituting upstream migration channel16Direction of decrease in stable slope at upstream of river with extension of upstream migration channel17HHWL decrease line with enlargement of flood discharge section due to lowering of riverbed accompanying15described above18Direction of river flow19Upstream migration channel20Direction of peak-cut due to upstream migration tsunami or storm surge of river or overflow of river flood21Returning flow of20described above due to change in ebb and flow22Direction of tsunami23Reflection of tsunami24Direction of tsunami or storm surge flow25Returning flow of24described above26Inland water area of “sea hollow (UTSURO)” B27Sediment trap outer levee constituting “sea hollow (UTSURO)”28Tsunami and storm surge invasion preventing levee29Sediment trap of “sea hollow (UTSURO)”30Inner levee constituting “sea hollow (UTSURO)”31Tsunami wave height32Calm water level of tsunami wave33Expanded water area of “sea hollow (UTSURO)”34Highly purification system using “sea hollow (UTSURO)”

REFERENCE SYMBOLS LIST

LR River extensionLm AltitudeLr Entire length of riverLt01Extension of overflow levee of initial upstream migration channelLv1Extension of deeply-scoured water area due to returning flow (leading end vortex flow) with placing of upstream migration channelLt02Extension of overflow levee obtained by extending deeply-scoured water area toward upstreamLv2Vortex flow length at leading end of overflow levee Lt Extension of river water area dominated by ebb and flow energyLn Extension of water area dominated by flow energy due to gravityB1, B2, and B3are levee bodies constructed by collecting mainly riverbed sediments in river reservation and longitudinally successively constructing low separation levees,G1, G2, and G3are movable dams placed on left and right sides of upstream and downstream every time longitudinal upward and downward movement by 1 to 5 m occurs.