As Hanoi braces for the wet season, concerns have been raised over the need to upgrade the capital city's dyke system.

Several sections of the city's dyke system has come under pressure from landslides. The Thanh Am dyke in Long Bien district has a lot of serious cracks and is in danger of crumbling beneath its own weight.

It's one of the areas with the greatest potential for disaster, as the Thanh Am dyke faces pressure from strong river currents where the Red River flows into the Duong River .

Nguyen Vinh Lien, deputy director of Hanoi 's Department of Dyke Management and Flood Control, said the riverbed at this part

of the river has been severely depleted during the last year, adding to the dangers.

The Sen Ho dyke is in a similar situation, with many cracks appearing in the dyke during the past 30 years.

According to Tran Xuan Viet, director of the Agriculture and Rural Development Department, the quality of nine dykes, totalling 273km in length, along the Da, Hong, Duong, Ca Lo and Cau rivers is below average.

Facing these threats, Hanoi authorities as well as the Ministry of Agriculture and Rural Development have determined to complete dyke improvements before the end of the month. Other dyke projects will finish at the latest by June 30.

"The best solution is to closely follow up with dike management, and to continuously improve the dykes before and after the rainy season," said Viet.

Do Duc Thinh, director of the Department of Dyke Management and Flood Control, said that the increasing prices of materials have made these projects cost more than what was planned, which has affected the implementation deadlines.

Meanwhile the northern port city of Hai Phong , one of the world's top ten most flood-prone cities, is also preparing its flood defences.

According to the Hon Dau Oceanographic Station, the sea's water level has increased on average by 2.5 to 3cm per year during the last decade. Encroachment by sea water is already causing problems in some areas of Hai Phong such as Phu Long commune, Cat Hai district and Do Son ward, Kien Thuy district.

In addition to its 125-km-long coast, Hai Phong has an interlacing river and stream system which requires a complex 422-km dyke system. However, six coastal dykes are only able to resist level-nine storms and low tides.

Recently, storms and high increased sea water levels have damaged some coastal defences meaning that upgrading dykes and embankments has become an urgent necessity.

"The problem here is the cost. As estimated, it costs 50-70 billion VND (2.6 million-3.6 million USD) per kilometre of dyke while budgets are limited," said Hoi.

Since 2006, Hai Phong has approved nine projects with a total investment of 1.1 trillion VND (57.8 million USD) to improve 60km of coastal dykes.

In 2008, the city began implementing a government programme worth 318.7 billion VND (16.7 million USD). The completed 19-km embankment with an investment of 300 billion VND (15.7 million USD) has been put on operation./.