Erosion devours 22 per cent of coastline

Thailand's 2,600-km coastline has suffered serious erosion, losing 79,000 rai of land, or 22 per cent, in the past 30 years, Chulalongkorn University scholar Thanawat Jarupongsakul said yesterday.

Thanawat, head of the CU Unit for Disaster and Land Information Studies, said the damage resulted from stronger and bigger waves triggered by climate change, while upstream dams leave less sediment at river-mouth areas. Previously, the Chao Phraya River mouth area dropped 17-18 million tonnes of sediment per year, but it now deposits only 1.6 million tonnes.

Thanawat suggested installing rows of triangle pole structures (50cm x 50cm x 50cm), with each row 150 metres from the next, at 500 metres from the shore, to cut wave impact by 40-90 per cent.

At hardest-hit Ban Khun Samut Chin in Samut Prakan's Pra Samut Chedi district, where 900 metres of land were gone as the coast eroded at 30 metres per year, a 250 metre-long structure had been built as part of a pilot project. But it is Bt10 million short of funding costs.

It could have halted erosion by over the past five years and created two metres of new land via sediment gathering, he said.