State of water environmental issues
4.1. Groundwater resources
Since there has not been a comprehensive national disclosure of facts on groundwater resources to date, key stakeholders lack information, knowledge and understanding of this natural resource. However, estimations by the Ministry of Water Resources and Meteorology show the amount of groundwater resources at 17.6 billion m³. Groundwater is being exploited at ever-increasing rates, particularly by shallow tube wells for community and household water supply, as well as for irrigation. There are at least 25,000 community water supply tube wells and large diameter motorised tube wells for irrigation, and about 2,000 manually operated shallow wells are being installed annually.
Besides the use of groundwater resources for domestic consumption and watering, it is also being used widely in the industrial sector (Ministry of Environment, 2002), even while the Law on Water Resources Management has not yet been approved by the National Assembly. Indeed, data and information relevant to the utilisation of groundwater and its quality is not available; however, informal estimations by concerned stakeholders show that if the agriculture and industrial sector continue to extract groundwater to meet water demands without being charged and responsible institutions do not exert regular control over this sector, there may be adverse effects from over-extraction.
The alluvial deposits in the Tonle Sap and Mekong floodplain/delta are believed to be excellent shallow aquifers, with high recharge rates and a water table generally within five to ten meters of the surface water. Shallow wells could be used in an estimated 48,000 km² of the country.
Groundwater quality is generally satisfactory. However, unpalatably high iron levels are encountered in about ten percent of tube wells, particularly in Kandal Province. Increased salinity is seen in parts of the southernmost (delta) provinces, most likely due to contamination by salt contained in the original deltalic deposits, and recent measurements indicate that water drawn from aquifers in some locations may cause health problems because of the high concentration of chemical substances. However, the status of groundwater contamination is not widely disseminated due to a lack of human resources, analytical facilities, technical skills, etc. Commonly, the conduct of groundwater quality surveys continues to be limited in comparison with surveys on groundwater quantity, which is the responsibility of the Ministry of Water Resources and Meteorology in collaboration with concerned institutions.
- Table of contents > 4. Groundwater
- 4.1. Groundwater resources
- 4.2. Groundwater in the study area within the Mekong River system (Takeo, Kandal, Kampong Speu, Prey Veng, Kampong Cham, Kamport, Koh Kong, and Phnom Penh Municipality)
- 4.3. Groundwater in the majority of provinces in the Tonle Sap sub-area