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  • Photo du rédacteurL'équipe de Clim'Adapt

Combating coastal erosion in Bangkok Bay

The Thai coastline covers 2,800 kilometres and is subject to fierce erosion that is increasing and worrying Thai authorities, populations and scientists. Of these 2800 km, nearly 30% are in critical danger, losing more than 5 meters of coastline per year. [1] The Gulf of Thailand is particularly affected, as shown by the sad symbol of Wat Samut Chin, surrounded by the waves in a few decades and whose floor has already had to be raised several times, as shown by the small size of the entrance doors. The various actors are engaged in this difficult fight with a deployment of initiatives that try to absorb the damage in the municipality.

Wat Samut Chin, a reluctant witness to coastal erosion in Thailand

We are only a few dozen kilometers south of Bangkok, in the northern Gulf of Thailand in Samut Pra Kan province. This flat coastal mudflat terrain is oriented towards family and peasant agriculture. Here it is aquaculture that prevails for the 70 families composing the village, but this has not always been the case. Previously, rice and maize and salt cultivation replaced the shrimp, fish and Tegillarca Granosa [2] – a shell - ponds.

This paradigm shift is implicated in the intense effects of coastal erosion on the coast. Indeed, to set up these more lucrative aquacultures, the inhabitants removed a mangrove that seemed problematic to them but which in fact protected them from the assault of the waves. However, in the middle of the tropical zone, these storms are common between May and October, i.e. during the monsoon season.

Associated with this change, and further aggravating the situation, the construction of dams upstream of the village, on the Bangkok catchment area, deprived the coasts of 70% of the sediment supply[3] which limited erosion. Finally, the last component, the rise in sea level - the 42 mm per year level in the Gulf of Thailand in the 2000s [3] - ensures a slow but steady nibbling on low and desperately flat coastal areas. Thus, poor management of the environment by man, combined with the intensification of coastal climatic phenomena and sea level rise, have caused coastal erosion that is among the most intense in Thailand.

Photo 1 : Destruction of a dwelling due to erosion - Inner Gulf of Thailand Conservation Network, the Thai Network for Disaster Management-2_12308.pdf

Erosion, which could be controlled before 1985, had surged over the past 20 years to levels above worrying levels. With more than 35 metres of land lost per year[1] - while a loss of 5 metres due to erosion is categorised as critical - Khun Samut Chin has lost 2 kilometres of land in about 50 years forcing people to abandon their homes threatened by the waves (Photo 1). Some have had to move more than 7 times, the school has been relocated inland on the other side of the temple, which now finds itself alone in the middle of the sea far behind the coastline where the aquaculture basins are located (Photo 2).

The witness of this retreat are the few power poles lost at sea, current witnesses of a past land-based human activity on these now maritime places. This untenable situation, for some of the inhabitants, explains the departure of 70% of them - i.e. 130 families - between 1974 and today.

The arrival of the Thai Chum Chon Foundation launches what will be the climate change adaptation project.

At the end of the 1990s, the Chum Chon Thaï Foundation became interested in the problem poisoning the life of this village. Its first actions were to bring people together, make them aware of the danger of erosion, create a coastal management committee and finally establish a network among all. At the same time, as aquaculture becomes almost mandatory because of the nibbling of agricultural plots, the foundation transmits the necessary knowledge to these farms.

Photo 3 : An aquaculture square within a basin open to the sea - Taken during our on-site visit

After the construction of human networks, the implementation phase of erosion mitigation methods begins in 2003. It is the bamboo plantation in a straight line along the coast that is chosen. These bamboos break the waves and limit their impact on the coast while leaving room for marine life to rush between the rods. Bamboos are special, they come from Myanmar where bamboos are wide and therefore resistant to the onslaught of waves.

Photo 4 : In the foreground the concrete pylon line / In the background in the diagonal, the bamboo barrier barrier - Photo taken during our on-site visit

More resistant, and especially with a much longer life expectancy than bamboos - 50 years compared to 2 or 3 years for bamboos - real concrete pylons have been placed around the temple. However, transporting these elements from Ayutthaya province, indefinitely heavier than bamboos, is much more expensive. The government has therefore decided not to place them all along the coast, although they are preferred by the local population for their longevity.

In addition to mitigating erosion, the objective is to capture sediment and re-sand the shoreline. These are rocks, directly associated with bamboos, because they are placed at their feet, which play this role best. These granites come from the provinces of Thailand 200 km from the shore. Transport is by boat.

During our visit, the community focused on deploying these rocks along the coastline where the bamboos are already being planted. But this installation is expensive. For the 1 km long installation, the cost to the Thai government is 20 million baths (about €580,000). On the other hand, the community can set up these rocks itself if it has the necessary funds and only 5 million baths (about 145 000 €), i.e. 4 times less than for the government. The reason? The Thai government employs private companies while the municipality involves the voluntary community.

Photo 5 : Installation in the heart of the municipality - Photo taken during our on-site visit

80% of the municipality's funds come from tourism, a conservation tourism that has developed in recent years. This tourism is intended for a Thai clientele. The host family pays part of its income to the Toursim Found of the commune up to 50 baths out of the 600 paid per night. The Tourism Found is then used to develop the community. With 100,000 tourists per year, half of whom - who are neither students nor from NGOs - pay for their nights, nearly 5 million baths go into the village coffers each year.

Erosion, contained, remains a challenge for the inhabitants

Since 2003, 160,000 m² of land has been resedimented and thus regained on the sea. These lands are the site of mangrove plantations, effective natural protection against erosion that still threatens the Thai coast.

The villagers now manage this project practically autonomously with a less strong presence of the Chum Chon Thaï Foundation, which is no longer just a technical support, but with the arrival of the NGO Action Aid, which has been training the inhabitants since 2018 in community management. The Village Committee, composed of 10 people, meets officially once a month but they meet more often, and ensures the good management and sustainability of this project. Symbol of the project's management by the inhabitants themselves, they refused the technique advanced by the Thai government after seeing the failure of this technique in a neighbouring village, Bang Pu. Sandbags to form dikes have only a very limited effect on coastal erosion.

As the infrastructure is not immortal, maintenance is necessary, especially for bamboos with a low life expectancy. The local storm called Mon Soon, which is not very violent but occurs every year, weakens the bamboo stems even more. The project is therefore continuously monitored.

On the financial level, coastal erosion has been a burden for the inhabitants who, despite the project and the development of tourism, have seen their income decrease.


Working in a meaningful area and demonstrating the extent of coastal erosion, this project has successfully stemmed coastal erosion on the selected parcels of land. The very good integration of the premises at the heart of the decisions and the necessary annual maintenance, assisted by the Chun Chom Thai Foundation and the NGO Action Aid and with the support of the Thai public authorities, whose employee supervises the project, ensures the sustainability of the project. Spread over a period of more than 20 years, the project is far from being finished before the entire eroded coastline is protected.

An important element that could accelerate the resolution of the problem in the Bay of Thailand but also in all the areas concerned could be unblocked. Erosion is not now considered a natural disaster by the Thai authorities in 2019, despite the fact that Bangkok has been ranked seventh out of 136 cities in the world most threatened by coastal flooding within seventy years in 2007 by the OECD (Organisation for Economic Cooperation and Development)[4]. The village cannot therefore benefit from the funds allocated for natural disasters. The committee is trying to change the law on this subject by using its example, a very high-profile example through its temple.

Our opinion

Access to the heart of the village is difficult and is via a paved road that allows only one car to pass through and then on foot, right on the dikes. The access road was the precursor of the upheavals known by this village. We were surprised to see the extent of the damage caused by coastal erosion but impressed by the means deployed in this small village to save their land. The manager, who was part of the local committee, who explained the ins and outs of the project to us, showed increased knowledge and thoughtful management of the proposed methods. With the international enthusiasm for this temple surrounded by the sea, we are certain of the bright future for the village even if we cannot say the same for the rest of the Thai coasts which are not beneficiaries of an adaptation project.


[2] Struggling against the Sea in Ban Khun Samut Chin: Environmental Knowledge, Community Identity and Livelihood Strategies in a Village Fighting Severe Coastal Erosion on the Gulf of Thailand

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