Audio-Magnetotellutic Method for Groundwater Exploration in Developing Countries

Despite high precipitation, large aquifers, and rivers Lebanon has recently experienced a shortage of potable water. This problem can be attributed to population growth, the high number of refugees, and inadequate water management. Lebanon’s water management policies have led to random and poorly managed water extraction from aquifers with resulting aquifer collapse and shrinking or disappearing streams. Studies were conducted in several areas (i.e., Batroun, Tarshish, and Kfarnabrakh) to determine the viability and quality of Lebanon’s water resources. Site testing and geologic maps in Batroun showed a meocene m2 formation (a semi-aquifer) with a 200 m thickness above sea level. The audi-magnetotelluric (AMT) method showed water shortage with salt water intrusion below seawater level. Depth and water quality studies will be conducted on another aquifer in this area to determine if it can provide potable water. A hydrogeological study in Tarshish showed the presence of four geologic formations: J6, C1, C2a, and C2b. AMT data indicated the presence of four layers, consistent with the data obtained from the hydrogeological interpretation of the section. Based on this formation it was determined three productive aquifers could be accessed with different water potential by drilling 70 m, 250 m, and 750 m into the C2b, J6, and J4 layers respectively. AMT soundings were carried out in Knaisseh using Stratagem EH4. A geophysical survey showed layers with dissimilar lithostratigraphic properties and corresponding depths. The AMT results corresponded with the geological cross-section showing three water-bearing layers (i.e., C2a, C1, and J6) with different resistivity zones. C1 and J6 were determined to be potential aquifers.