State of water environmental issues
Ground Water
The groundwater resources in Viet Nam are abundant – with the total potential exploitable reserves of the country's aquifers estimated at nearly 60 bill. m³ per year. The availability varies from abundant resources in the Mekong River Delta to somewhat limited resources in the North Central Region (Fig 6).
| Fig 6. Exploitable Groundwater Bill. m³/year |
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Source: National Water Sector profile, 2002.
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However, despite the abundance of groundwater reserves, only less than 5% of the total reserves are exploited, for the country as a whole. The abstraction of groundwater also varies. For example, groundwater exploitation is difficult in the Northeast because the reserves are scattered and diverse. In the Central Highlands, on the other hand, groundwater is exploited heavily for irrigation of cash crops resulting in shortages of water in parts of this region. In the Red River and Mekong River Deltas groundwater is exploited beyond the recharge capacity around Hanoi and HoChiMinh City. This over-exploitation is resulting in falling water tables – further causing land subsidence and salinity intrusion, especially in the Mekong River Delta.
Mineral and thermal water resources are abundant in Viet Nam, good in quality and varied in types having great value for different purposes such as balneological treatment, bottled mineral water, geothermal energy, extraction of CO2 gas etc. According to investigation there are about 400 mineral and thermal water sources in the country, of which 287 sources have been exploited and reliable data exist (Table 11).
| Table 11. List of Mineral and Thermal Water Sources |
| Region |
Number of Sources |
| Springs |
Boreholes |
Springs/
Wells |
Total |
| Northeast |
83 |
1 |
3 |
87 |
| Northwest |
7 |
5 |
2 |
14 |
| Red River Delta |
1 |
15 |
1 |
17 |
| North Central Coast |
14 |
4 |
4 |
22 |
| South Central Coast |
30 |
4 |
22 |
56 |
| Central Highlands |
18 |
6 |
|
24 |
| Northeast of Mekong |
1 |
11 |
1 |
13 |
| Mekong River Delta |
|
54 |
|
54 |
| Total |
154 |
100 |
33 |
287 |
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| Sources: MOI 1999. Mineral and Thermal water resources in Viet Nam |
Groundwater quality:
Groundwater is emerging as an important source of water for domestic, industrial, and agricultural uses. While the quality of ground water remains good, there are some pockets of contamination. There is evidence of pollution –from poorly maintained septic tanks, garbage dumping, and industrial effluents and overexploitation in parts of Hanoi, HCMC and the Mekong River Delta.
New investigations have shown potential problems related to the presence of arsenic in alluvial deposits in the Red River region and in tubewells pumping water from lower aquifer10. This requires further study and careful assessment. In addition nitrogen and iron levels above the admissible standards are found both in the Red River (Box 2) and Mekong River Deltas.
| Box 2. Ground water pollution in Hanoi |
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A research project in Hanoi has shown an alarming sign of ground water contamination by ammonia in the South of Hanoi. The level of ammonia in the treated water at the three treatment plants is higher than the national standard by 2-8 times. All samples taken from the upper aquifer exceed ammonia standard many times. Scientists estimate that with the current abstraction rate of 700,000 m³/day, there will be a high risk of lowering the water table down to 114 m and the groundwater pollution would spread over the Hanoi city.
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| Sources: VEPA website http://\www.nea.gov.vn (Jun 11, 2003). |
Salinity intrusion: A pressing issue is the salinity intrusion taking place both in the Red River Delta, the Central Coastal Regions and in the Mekong River Delta. Salinity intrusion is a natural phenomenon in coastal areas. However, due to increased groundwater exploitation salinity intrusion increases and poses a threat to safe water supply e.g. in the Red River and Mekong River Deltas.
In the Red River Delta, salinities higher than 3% stretches more than 60 km inland to Hai Duong in the north and Nam Dinh in the south of the delta. In the Mekong River Delta, saltwater is registered in half of the delta area.
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