Bamboo Wavebreakers Help Coastal Erosion

[sbk]

Living right on the beach as we do we also have erosion issues, so I was wondering if anyone had any suggestions as to exactly how this might be implemented. ie, how deep the poles need to be buried, spacing etc etc

Bamboo wavebreakers helping coastal erosion

Villagers erected Bamboo poles along the two kilometer shoreline to tackle the coastal erosion problem, after it caused the loss of almost 3,000 acres of land. The project has proven successful after one year, with sediment deposits behind the bamboo wall forming new land more than one meter from the shoreline.

Narin Boonruam, the project initiator, said his idea about the bamboo walls came from the local way of life. Villagers raised mussels attached to bamboo poles to earn a living. He learnt the method to make the poles stable along the shore. He increased the number of bamboo poles to make wave breakers and placed them 50 meters from land. The wall reduces wave speed and creates a habitat for young marine creatures.

Local residents in the province of Samut Sakhon have built bamboo walls along the coastal area to fight shoreline erosion. The bamboo poles act as wave breakers and help deliver sediment to the shoreline and form new land area. More details in this report from Thai News Agency.

Narin Boonruam, a project initiator said “The bamboo poles were erected in a zigzag shape to damper waves. The poles are not only wavebreakers but also cause transport and deposition of sediment behind their line.”

Samran Rakchart, Deputy director-general, Dept of Marine and Coastal Resources said “The deposits form new land. When it’s hard enough, we plant trees on it to increase the mangrove forest area.”

It’s expected in the next seven years, about 40 acres of new land will be formed and the number of marine animals will increase. The Department of Marine and Coastal Resources plans to use the bamboo wall project in Samut Sakorn as a prototype to tackle the problem of shoreline erosion nationwide.

Features : Last Update : 08:38:31 5 September 2008 (GMT+7:00)

[Rimmer]

What a great idea same action as a natural mangrove swamp which slows the waves and cuts erosion.

Looks from the picture that the poles are a good way in the mud, maybe up to 50% of length.

From living next to mangroves in Singapore and Malaysia I would think that they don't even need to be build into thick walls just a lot of them randomly placed, Can you do a pilot scheme and see which breaks down the wave pattern best. Problem with walls of any kind on a river or on the sea is they can alter the tidal patterns somewhere else.

Edited September 5, 2008 by Rimmer

[Cuban]

If you are suffering from longshore drift, you might be able to use some of these ideas from the UK.

Image Link.

However I understand that the affect of the flow of water can have a significant effect on any pilling in sand or mud, looking one of the bridges up in Pai after the floods of some years ago - you can clearly see that after the water passed a support pillar the sand/mud downstream was eroded away leaving a hole into which the support would fall. I would expect the solution to be to protect that surface with some matting in the case of single pillars (bamboo poles)?

The problem is that things that act as erosion breaks sticking in the water are seldom natural and beautiful.

Would you be allowed to install a pier - and plant the spaces between supports with some type of reed?

Difficult to fight the seas.

[sbk]

Cuban, your link to longshore drift takes me to a thai visa thread about grounding taps in bathrooms

But, yes, longshore drift is our problem, except that each year the beach gets smaller and smaller whereas before it would move, but be replenished. Mainly because the Or Bor Dor built a channel in the reef, and blocked off the natural flow of water. So, the sand gets moved down, but because of the blockage, never gets moved back.

I'd say in terms of beach size, we have lost at least 4 meters of beach front in the past 5 years. Depth, probably about 1.5 meters. Naturally, the Or Bor Dor has no plans on rectifying the problem they created.

[0Mix1up]

probably to hard or $$$ but can you dredge sand back to your beach?

[Cuban]

Please accept my apologies, the result of switching between threads while I wait for a page to load or mull over wording of a reply. Correct link.

If you are not able to create a physical barrier in the form of a pier etc. (too obvious or draws unwanted attention) could you 'build' somethng below the low-water level? Your own artifical reef, car tires, not difficult to place with snokling gear. From talking to a guy I know down on Koh Chang, I understand that the state 'own' the coast line so building in the sea might attract a response from someone, however if it doesn't affect anyone else these things (from observation) seem to be ignored.

I assume there are others in the area that are also affected by this new erosion? Any local political will to 'do something' en-mass? I guess it depends if they want a beach for tourists or deeper water moorings for boats.

Just make sure your taps are firmly grounded.

[Shotime]

Erosion is a natural phenom, and is also seasonal. What you do affects the natural patterns elsewhere. Once someone starts protecting their shoreline, it affects the shoreline elsewhere. Not sure when your erosion problem started, but someone must have put up a seawall somewhere up the coast. There was, and probably still is, a major problem on the NJ shore because people/companies installed jettys, seawalls, etc., along the shoreline. It's difficult to say how deep you need to place the poles, as it depends on the size of the waves, currents, etc. Difficult to mess with Mother Nature.

Sorry to be repetitive. I just saw some other comments added.

Edited September 6, 2008 by Shotime

[Cuban]

....dredge sand back to your beach?

Indeed - if you are not too worried about nice clean tourist friendly sand, dredged sand/stone etc. could be used to build out your (and neighbours) beach. Your objective should (?) be to slow down the water flow to allow the eroded sand to settle out of the movng water, re-enforcing your beach not someone's downstream.

[Rimmer]

Please accept my apologies, the result of switching between threads while I wait for a page to load or mull over wording of a reply. Correct link.

Just make sure your taps are firmly grounded.

A well grounded and bonded mangrove swamp is the answer.

[sbk]

Shotime, yes it was built about 6 years ago and is the direct cause of our current problems. Political will is indeed in short supply on this island. I do not see the local govt doing much of anything frankly, so doubt that they will do anything to solve this problem much less others that crop up. Its a pity nobody bothered to do an environmental impact study before building the wall, but there you go.

However, given their lack of activity, I also doubt they would do much of anything if we made any efforts to try to rebuild our beach. If it weren't creeping up so close to our house at this point, I probably wouldn't be bothered, but each successive year gets the breakwater closer and closer to our house (which, btw, was at quite a safe distance from the shore when we built it).

Dredging sand isn't really an option, we are inside the reef, which is quite far out, and nowhere to steal sand from . However, the water is extremely shallow (at times of the year, totally dry at low tide) so putting a solution into place wouldn't require diving.

Thanks for the suggestions, and feel free to keep them coming.

[jts-khorat]

Shotime, yes it was built about 6 years ago and is the direct cause of our current problems. Political will is indeed in short supply on this island. I do not see the local govt doing much of anything frankly, so doubt that they will do anything to solve this problem much less others that crop up. Its a pity nobody bothered to do an environmental impact study before building the wall, but there you go.

However, given their lack of activity, I also doubt they would do much of anything if we made any efforts to try to rebuild our beach. If it weren't creeping up so close to our house at this point, I probably wouldn't be bothered, but each successive year gets the breakwater closer and closer to our house (which, btw, was at quite a safe distance from the shore when we built it).

Dredging sand isn't really an option, we are inside the reef, which is quite far out, and nowhere to steal sand from . However, the water is extremely shallow (at times of the year, totally dry at low tide) so putting a solution into place wouldn't require diving.

Thanks for the suggestions, and feel free to keep them coming.

Here on Phuket even multi-billion Baht projects have immense difficulties to get piers and other shore line structures approved, so my assumtion would be that you will run into not small troubles should any of your neighbors be critical of your bamboo project -- this might easily happen, as other places down-stream might have more erosion because you keep 'stealing' their sand (and even if not true, facts are often not important in decision-making).

Since the problem was created by the Or Bor Tor, some of them might loose face if weaknesses of the old canal are publicized; then you have the actual policy-makers in your region actively against you, not a nice prospect at all!

As hard as it sounds, keeping your head down as long as you do not have major Thai-side backing for your plan seems to be the right way to go about it (or at least ask a lawyer about structures within 25 meters of the high-tide line, which is the limit as far as I am aware).