Coastal protection in the Gulf of Thailand

Swimming against the tide
Sombat Raksakul, Bangkok Post 16 Nov 08;

Residents of coastal areas want to protect their shorelines against erosion, and they say the government is going about it the wrong way.

The fertile muddy coast along the upper Gulf of Thailand is a fisherman's paradise. Neither trawlers nor modern fishing equipment are needed to make big catches due to a combination of delta marshes and mangrove forest that provide an abundant supply of food for marine life.

But soon the marshes and the forests could be gone, washed away by the waves. Much of the coastline of the capital and its adjacent provinces is suffering serious erosion. For decades, the seaside provinces have been experiencing extensive losses of shoreline each year.

Bangkok, Samut Songkhram, Samut Sakhon, Samut Prakan and Chachoengsao provinces are suffering severe erosion according to Master Plan on Coastal Erosion Management for the Upper Gulf of Thailand, published in September by the Thammasat University Research and Consultancy Institute, which studied the coastline covering 100km of shoreline from the mouth of the Mae Klong river in Samut Songkhram to the mouth of the Bang Pakong river in Chachoengsao. Some 2,667 hectares of this coastline was washed away in the 54 years from 1952 to 2006. The problem is severe and the rate of erosion is increasing. Local communities are suffering economic damage estimated at more than 100 million baht a year, according to the institute's report.

Among the worst affected areas are Bang Khun Thian district, the site of Bangkok's fastest-disappearing coastline, and its neighbouring district, Phra Samut Chedi in Samut Prakan province.

Located in the Chao Phraya river delta, these two districts are at greater risk than most coastal areas due to land subsidence caused by excessive commercial use of groundwater over many years.

Analysis of the Thammasat University research shows that Ban Khun Samut Chin in Phra Samut Chedi is hit by strong waves all the year round and loses roughly 28m of coast a year.

For decades, people in the village have been forced to move inland, abandoning parts of their community and farmland to the encroaching seas, said Samon Khengsamut, Ban Khun Samut Chin's headwoman, who has been fighting coastal erosion for 30 years.

With a slow response from government agencies, residents have had to try to combat the erosion themselves. They have built small seawalls of soil, and some residents have tried strengthening their seawalls with rocks and old tyres.

The problem for state officials is that coastal erosion mostly occurs on private land, not public or state-owned land, and this has made them reluctant to take responsibility for the problem, said Assoc Prof Uruya Weesakul, Thammasat University's research project manager.

"By pouring huge sums of state money into solving problems on private land, the authorities think they risk allegations of corruption," Assoc Prof Uruya explained.

But as the erosion becomes worse and is more publicised, someone has to take responsibility.

Without public participation, the officials, in their bureaucratic way, have instigated mammoth and expensive shore protection schemes such as placing submerged off-shore breakwaters in ecologically and socially sensitive areas, which inevitably created conflict with local people.

The reasoning behind such plans seems to be "because they think the big hard structures are strong, have longer life spans and are low-maintenance", said Mr Uruya.

But what is convenient for officials may not be so for local people. Moreover, such hard structures are not suitable for muddy beaches. That is why the residents at Ban Khun Samut Chin opposed the sandbag-seawall project proposed by Samut Prakan's administrators.

"For many years, we sought help from them. But they only came around recently and offered a project that we don't want," Ms Samon said bitterly.

"Residents prefer breakwaters," said the 52-year-old community leader, referring to the design of a team of engineers and coastal experts from Chulalongkorn University.

That team, lead by Assoc Prof Thanawat Jarupongsakul, a lecturer on climatology at the science faculty's Unit for Disaster and Land Information Studies, is experimenting with the construction of an off-shore breakwater for the village's muddy beach. The barrier consists of around 500 concrete pillars arranged in a zigzag pattern, with the aim of dissipating the force of the waves _ preventing them from damaging the beach _ and trapping sediment in the spaces behind the breakwater to help build-up the beach.

In order to avoid conflict with local people, in the first stage of the experiment, the team hired 10 locals to help with gathering information and monitoring the accumulation of sediment.

"The breakwater not only protects existing areas but it also brings more mud to the beach for aquaculture, which many people can use to earn money farming prawns and mussels," Ms Samon said.

Bang Khun Thian is facing similar problems, with a reported a loss of more than 160 hectares along its 5km shoreline.

In response to the problem, Bangkok Metropolitan Administration officials proposed a 316 million baht project to construct breakwaters and groynes. And again, local residents disagreed with the officials' plans. Living with, and earning their living from the sensitive coastal ecology, Bang Khun Thian residents have learned from the mistakes of other coastal communities, and say the groynes would do more harm than good.

"The groynes, breakwaters and sandbag walls may work on sandy beaches, but they are not the right solution to the problems in this area," said Suthin Onfung, chairman of Bang Khun Thian's community organisation council. Mr Suthin said residents were afraid of using groynes, and a sandbag-wall would have an immense effect on the fragile muddy beach.

In the neighbouring provinces of Samut Prakan and Samut Sakhon, said the 58-year-old community leader, local officials protect their coastlines with sandbag walls, but the bags break up and the sand from them could cause damage to the sensitive ecology, particularly on mud beaches that are a vital habitat and nursing ground for marine life.

In an attempt to stop the BMA project, a group of Bang Khun Thian residents recently petitioned His Majesty the King. They demanded that City Hall review its plans, and they proposed the construction of breakwaters made of bamboo.

"The idea of the bamboo wall comes from the local knowledge of our ancestors, and is appropriate for the ecology of a mud beach," said Mr Suthin.

Locals are in the process of surveying locations along the shoreline, and the planned construction and budget estimates for the bamboo breakwater, they say, are expected to be completed within four months, before proposing the project to His Majesty for consideration.

In addition to the breakwater, residents of communities in Bang Khun Thian, led by Seksai Chindachom, 40, are planning social and ecological conservation projects. Firstly, they say they are planning to establish a learning centre to promote tourism and raise public awareness of the issues.

Bang Khun Thian Aquaculture Centre is described as a "nature-learning centre", and residents are looking for a site in the area for a new building for seminars and meetings. Mr Seksai said the group would also encourage villagers to open their homes to tourists.

This eco-tourism project, he said, would be promoted in six seaside villages in tambon Thakham of Bang Khun Thian, which would not only create income for local people but also encourage them to realise the importance of the conservation of their coast.

Nature's greatest threat
Study says human activity - not climate change - is the cause of coastal erosion.

Sombat Raksakul, Bangkok Post 16 Nov 08;

Every year, coastal erosion causes misery to millions living in the upper Gulf of Thailand - Bangkok, Samut Prakan, Samut Sakhon, Samut Songkhram and Chachoengsao. Politicians, the authorities and environmentalists alike commonly attribute the problem to climate change. But according to a study by Thammasat University Research and Consultancy Institute, they are wrong.

Many reports on coastal erosion blame climate change, but this is partly because records on the impact of global warming on climate change and sea levels are not systematic and partly because state agencies and academics work separately, and lack information on climate models. Assoc Prof Uruya Weesakul, the research project study's manager, however, thinks there is no evidence to link erosion with climate change.

In the Master Plan on Coastal Erosion Management for the Upper Gulf of Thailand, published in September, the research team found that global climate change is not a cause of coastal erosion.

The coastal expert said the results of the research point to human activity causing coastal erosion. For example, the excessive commercial use of groundwater in Bangkok and its neighbouring provinces over the years has caused land subsidence - one of the principle causes of coastal erosion.

Contrary to popular belief, the report says, in reality climate change has had only a limited effect on coastal erosion.

"The rise in sea levels is small when compared with the rate of subsidence. Sea levels are predicted to rise in the long term, but analysis of 50 years' data shows that the effect of land subsidence in the upper Gulf of Thailand is a key factor," says the report, which studied the area from the mouth of the Mae Khlong river in Samut Songkhram province, to the mouth of the Bang Pakong river in Chachoengsao province and 100km of coastline that has suffered severe coastal erosion.

Although the rate of subsidence in Bangkok has reduced since the Groundwater Department in 2006 implemented its plan for the reduced use of groundwater, the rate is rising in Samut Sakhon where a number of factories moved from neighbouring provinces and are now pumping increasing amounts of groundwater, the report says.

The Natural Resources and Environment Ministry appointed the Thammasat University team, led by Assoc Prof Uruya, to research coastal erosion in the upper Gulf of Thailand. The one-year project finished in September, and the results are now on the table of the chief of the Department of Marine and Coastal Resources.

"It is true that climate change has caused temperature changes over the past few years," said Assoc Prof Uruya, dean of the engineering faculty, "but the results indicate that other factors are the real culprits behind the erosion, including land subsidence, high waves in monsoon season, loss of sediment from rivers and changes of land use, mainly the loss of mangroves and the excavation of soil for aquatic farming."

One finding - the impact of two dams, Bhumibol, constructed in 1964, and Sirikit, constructed in 1974 - is the most surprising. Both dams have long disrupted the natural flow of water, but they also interrupt the flow of sediment to downstream areas, causing disaster for the shoreline of the upper Gulf of Thailand. Fortunately, the research team did not suggest the demolition of the dams to increase sediment supply, only suggesting solutions such as using breakwaters to trap sediment.

In the study's comprehensive report, apart from the background and causes of coastal erosion, there is also an evaluation of coastal protection structures, classified in four main sections - bamboo breakwaters; revetments, concrete seawalls and dykes; concrete breakwaters; and sandbag breakwaters. The report explains the strengths and weaknesses of each structure, for example sandbag breakwaters are hard structures that can effectively protect shorelines almost completely, but they cannot trap sediment, which is an important function for the process of coastal rehabilitation.

The report also aims to assess the changes to our coastline and provide efficient measures to protect it, taking into account environmental and aesthetic considerations. The target of the study is to propose measures to rehabilitate the eroded areas, and these areas will be made coastal ecosystem conservation areas.

Like other contemporary studies, the research team's report also emphasises the importance of public participation, which would help government agencies avoid conflicts with local communities.

But if the results of the one-year study say that climate change has nothing to do with erosion, why does it seem to be getting worse?

The problem is that more people now live and work near the coast - urban areas have spread, despite the risk of erosion, the coastal expert said, adding the rapid coastal population growth is mainly a reflection of population growth, increased investment in infrastructure. "Coastal erosion, in fact, is no worse today than it was in the last century," Assoc Prof Uruya concluded. "It's Bangkok that's sinking, not the sea level rising".