The potential devastation a tsunami would create in the Vancouver area and the Lower Mainland is enormous, to the point of creating a national disaster for Canada. As such we must think in terms of protecting the population, buildings and infrastructures in the Lower Mainland at reasonable costs to help control the source of possible destruction. In the event of a major tsunami, it is out of the question to evacuate in time up to one million people from the most vulnerable areas. Thus this project gives an alternative to the prospect of major destruction in the city and its people.
Contrary to other tsunami defence mechanism which consists mainly of solid walls of different materials and shapes, this proposal aims at creating a series of movable gates that could be raised up a few meters above high tide sea level. The movable gates would neither obstruct passages to ships nor interfere with water flow or sea life under normal condition but would be in full force pending a tsunami alert. The main principle is to break the tsunami waves well before they reach the shores by acting as buffers and deflectors.Made of horizontal panels supported by pillars inserted in the bedrock (seefloor) this moving structure would sit at the bottom of the sea during normal period but would be raised up if a tsunami alert is triggered. Insertion of pillars into the sea floor at a certain distance from one another would insure the stability of the structure at high water pressure level. These posts would act as support structures for the movable gates to be raised in place and act as buffers against incoming upsurge of water. Since it is not a solid wall but rather a semi-wall it would still allow the water to flow through but at a diminished speed and force. In that sense two barriers at a distance equivalent to the wavelength of a tsunami wave - in the range of a few hundred meters from each other - are of the utmost importance. Only this would allow for an efficient buffering and breaking ot such waves. As we know the dynamics of tsunami waves which are moving through pressure reach for the most remote inner landscapes of a coast such as inlets, fjords, bays and the like. This tusnami defense mechanism should then be erected to deflect the water from entering these areas by artificially providing an alternative route for the flow of waters.
October 2011
Marc Bédard Pelchat
Montréal, Québec, Canada H4E 2E9
+1.438.829.6665 (GET TAZ MONK)
Contrary to other tsunami defence mechanism which consists mainly of solid walls of different materials and shapes, this proposal aims at creating a series of movable gates that could be raised up a few meters above high tide sea level. The movable gates would neither obstruct passages to ships nor interfere with water flow or sea life under normal condition but would be in full force pending a tsunami alert. The main principle is to break the tsunami waves well before they reach the shores by acting as buffers and deflectors.Made of horizontal panels supported by pillars inserted in the bedrock (seefloor) this moving structure would sit at the bottom of the sea during normal period but would be raised up if a tsunami alert is triggered. Insertion of pillars into the sea floor at a certain distance from one another would insure the stability of the structure at high water pressure level. These posts would act as support structures for the movable gates to be raised in place and act as buffers against incoming upsurge of water. Since it is not a solid wall but rather a semi-wall it would still allow the water to flow through but at a diminished speed and force. In that sense two barriers at a distance equivalent to the wavelength of a tsunami wave - in the range of a few hundred meters from each other - are of the utmost importance. Only this would allow for an efficient buffering and breaking ot such waves. As we know the dynamics of tsunami waves which are moving through pressure reach for the most remote inner landscapes of a coast such as inlets, fjords, bays and the like. This tusnami defense mechanism should then be erected to deflect the water from entering these areas by artificially providing an alternative route for the flow of waters.
October 2011
Marc Bédard Pelchat
Montréal, Québec, Canada H4E 2E9
+1.438.829.6665 (GET TAZ MONK)
For the Metro Vancouver area, a first phase of this project should be erected to protect English Bay, the downtown area from incoming surge of water, as well as inland in the Burrard Inlet, which would be the final destinaton of tsunami waves. This part of the project is 4,5 km long. The second phase - longer - should be erected to protect the airport (YVR) as well as all the suburbs south, down to the mouth of the Fraser River, an area of low ground level with a populaton of over a million. Eventually It could involved our neighbour to the south (the State of Washington, the US government) in embarking in such a project.
In the case of a strong tsunami, most of the area south would suffer considerable damage to perhaps the point of being wiped-out since the waters could reach deeply inland, not unlike Sendai, Japan in March 2011 or Banda Aceh, Indonesia, in December 2004.
Another possibility which is based on the idea of a comprehensive project would be to erect the barrier from West Vancouver to Tsawwassen and further, eventually even covering the Bundary Bay. This has certainly the most certain safety aspect that the two preceeding phases would not have since it would skip the complicated interchange at the UBC level between phase one and two, considering the cliff of UBC acting as a buffer zone is not warranted, since the soil composition in this area doesn't allow for much resistance to major tsunami waves.
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From Locarno Beach, the raised barriers, invisible otherwise except for the pillars.
The idea behind the structure consists in allowing the flow of water, for it would be all but impossible to stop the surge of incoming water from a tsunami, yet it is feasible to diminish its intensity and deflect or redirect the waves. The basic characteristic of the structure employs buffering as the means to control the flow of water so it does not come as strong on the shores. The venetian blinds is a good example of the type of structure at work here.
Figure 4 shows the structure as it looks underwater as it has been put in full force
Figure 5 shows the process of either raising up our down a mechanism that would act as a barrier to slow considerably the surge of water of a tsunami force sea. The comparison to venetian blind is approximative but gives a good idea of the way the mechanism would work.
Figure 6 show a pillar sideways and how it would allow the piling up of the movable gates at the bottom of the sea.
Figure 6 show a pillar sideways and how it would allow the piling up of the movable gates at the bottom of the sea.
Kamaichi, Japan
The proposed movable gates could be erected where necessary to protect broken coastlines which are proned to tsunami waves incursions.
Scale Model
Scale model
Some have accused the Kamaichi walls as being responsible for the destruction of other areas up north. Other have questioned altogother the efficiency of the barriers/walls.
In this instance it is arguable that a wall that is conceived in this way is proned to the results it incurred for at least two reasons:
1) Due to the nature of the area which is a harbour, it is next to impossible to completely close the area from incoming water and sea traffic, thus allowing for a tsunami to easily get through. Moreover the very shapes of the walls allow for a funnel like narrowing of the flow to take place.
2) A tsunami defence mechanism must be conceived in a way it allows the water to be deflected. Here obviously the water pressure had nowhere to go but hit the wall and destroyed it like a castle of cards as we can see in one of the video taken that day by someone in Kamaichi.
1) Due to the nature of the area which is a harbour, it is next to impossible to completely close the area from incoming water and sea traffic, thus allowing for a tsunami to easily get through. Moreover the very shapes of the walls allow for a funnel like narrowing of the flow to take place.
2) A tsunami defence mechanism must be conceived in a way it allows the water to be deflected. Here obviously the water pressure had nowhere to go but hit the wall and destroyed it like a castle of cards as we can see in one of the video taken that day by someone in Kamaichi.
The proposed movable gates could be erected where necessary to protect broken coastlines which are proned to tsunami waves incursions.
Scale Model
Scale model
In this case as in any other a scale-model of the workings of this tsunami defense mechanism would have to be built. Only it could determine if the resoning about this concept makes it and gives the results hoped for. A tsunami scaled-model was made to see how a tsunami would hit a coastal town, Seaside, Oregon. In a CBC documentary - Shock Wave - this experiment was shown in this 90 minutes long film which takes a look a the devastation triggered by tsunami waves.
Shock Wave, CBC Television, December 27, 2009
ConclusionAlthough this presentation has its flaws, it should not be dismissed right off for that reason. In the realm of proposals anything goes! Considering the chances of a tsunami of great strength anywhere in the Pacific Rim, we should take all the ideas out there and make an assessment of their workability. The end result could be the safety of millions of people. As we discovered with the December 26, 2004 tsunami in part of the south Asian and Indian subcontinent coasts, mangroves would play a great roles in some areas where the have been preserved. Mangroves are hardly concrete walls but they helped in slowing down the incoming tsunami wave. All coasts can't be restored with mangrove barriers or they would not grow everywhere in any case. Thus this proposal takes into account this reality and offer a man-made barrier that is both financiallly, physically feasible and could mean the difference between total destruction of territories, structures and people. In that sense it is worth spending some time and money to verify its potential which is not of my reach. Considering the staggering high cost of a concrete barrier in the Kamaichi Bay (1,6 billions dollars), this proposal at least has the merit to cost a small fraction of this and could prove to be way more efficient.
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