The use of transient electro-magnetism method to localize saline water intrusion in Sri Lanka

On the east coast of Sri Lanka, groundwater resources mainly consist in coastal aquifers, which are exploited for both irrigation and domestic purposes. In case of an intensive exploitation, saline water intrusions can occur, which make the water in wells improper for consumption. Considering the future resettlements of internally displaced families in coastal areas, and in order to evaluate the potential of these coastal aquifers (before launching a well implementation program), one need to locate the extent of this saline water intrusion. This information can be obtained by intrusive means such as piezometers monitoring, or non-intrusive means with geophysical methods. Transient Electro Magnetism (TEM) method has been used on different coastal sites on the east coast of Sri Lanka and has given good results for estimating the aquifers geometrical parameters. This first study will be followed by a more complete geophysical survey involving other methods.