A section of sea dyke in Nam Dinh province's Hai Hau district. (Photo: VNA)

Can Tho (VNA)
- Groundwater levels along thousands of kilometres of coast stretching from northern Hai Phong City to southern Ca Mau province have dropped to alarming levels due to overexploitation for daily use by households.

The issue was flagged up by international environmental experts and officials from the Ministry of Natural Resources and Environment at a conference on coastal water resources management and groundwater management in Southeast Asia organised in Can Tho City on January 19.

Nguyen Chi Cong, Deputy General Director of the ministry's National Centre for Water Resources Planning and Investigation, said most provinces and cities nationwide exploited groundwater for both household and business use.

But in the coastal provinces in the Mekong Delta, the reliance on groundwater for daily use and drinking was total, he said.

The groundwater exploited daily in the country is five million cubic metres a day, he said, predicting the number to rise further to meet new demands thrown up by urbanisation and development.

Experts also blamed the lack of knowledge among the public about groundwater and climate change and sea level rise for the falling water tables, land subsidence, water pollution, and saltwater intrusion in coastal provinces.

A recent study done in HCM City and Hai Phong City and the provinces of Nam Dinh, Ca Mau, Soc Trang, Bac Lieu, and others found water tables to be at record lows.

In Nam Dinh province's Hai Hau district, it has fallen by 10 metres in just the past decade; in HCM City, it has fallen by 18 metres since 1995.

The quality too has deteriorated, with the water being polluted and saline in many places and failing to meet the standards required for drinking.

Nguyen Chi Nghia, also from the centre, said a sharp reduction in surface water due to overexploitation in the upstream of rivers had caused severe intrusion of saltwater.

The overexploitation of groundwater had caused land to subside in HCM City, Ca Mau province, and Can Tho City, he said, warning the challenge was immense since Vietnam has 3,000km of coastline.

Adichat Surinkum of the Co-ordinating Committee for the Geoscience Programme in East and Southeast Asia, one of the conference organisers, said Vietnam was among countries that rely mostly on groundwater and where exploitation was increasing.

The National Centre for Water Resources Planning and Investigation, another of the organisers, has worked with the Ministry of Natural Resources and Environment to do a survey to determine the permissible limit of groundwater exploitation in large cities and coastal areas.

The ministry has almost finalised the limits for most major cities, and the study results will act as the basis for water management and exploitation planning in future.

The conference was organised together with the German Federal Institute for Geoscience and Natural Resources.-VNA