Hau Giang resorts to earthen embankments to prevent erosion along rivers

Hau Giang (VNS/VNA) - Embankments made of natural materials to prevent erosion along rivers and canals have proved so effective in Hau Giang that the province plans to expand the model.

Two years ago the Mekong Delta province’s Irrigation Sub-department built three such embankments running a total length of 380 metres in Phung Hiep district and Nga Bay town on a trial basis. 

They were made by filling eroded areas with soil and erecting between them and the water a barrier made from cajuput trunks or bamboo. Permeable fabric or fine nets were installed outside the barrier to hold the soil.

The barriers also cushion the banks from ripples and waves caused by travelling boats.

Cajuput and other plants that grow in water were then planted inside the barriers so that their roots bind the soil against erosion.

They cost 350 million VND (15,000 USD). Their cost per metre was only 400,000 VND (17 USD) compared to 60 million VND (2,580 USD) for concrete embankments, according to the sub-department.

Besides, the trees planted in them generate an income of 700,000 – 900,000 VND (30 – 38 USD) per metre in three or four years’ time. 

The province then built another 25 kilometres of similar embankments last year and 143 kilometres so far this year.

In Bung Tau town in Phung Hiep, some 100 households along the Bung Tau and Ngang canals have built these embankments near their houses.

Cao Van Boi, who built a 30-metre embankment in front of his house in Bung Tau’s Tan Phu A2 Hamlet, said many large boats traverse the canal, and without something to block them, the waves caused by the boats hit the canal banks and cause erosion. “The embankment helps stabilise the bank.”

Besides cajuput, Boi has also planted spotted mangroves in the embankment. He grows water hyacinth in the canal to absorb the energy of the waves until his plants grow large enough.

Tran Thanh Oai, chairman of the Bung Tau town People’s Committee, said locals have built 2,000 metres of embankment under the guidance of officials.

The cost is borne by the locals themselves in some places.

The town plans to build more embankments and also instruct residents in building them, Oai said.

Tran Thanh Toan, head of the sub-department, said the embankments are a sustainable solution since they offer reliable protection and are cheap and environment-friendly.

Their use should be widely and regularly propagated to educate officials at all levels and the public, he said.

The province has a dense network of rivers and canals extending nearly 3,500 kilometres.

It has suffered from nearly 250 cases of erosion in the last five years, losing 25,000sq.m of land.

Truong Canh Tuyen, deputy chairman of the provincial People’s Committee, said the province has also built concrete embankments, but their high cost is an inhibiting factor, he said.

The earthen embankment is an appropriate solution and the province would expand its use, he added./.