Thesis: Lippert, Detection of a Submarine Aquifer Offshore of Israel using LOTEM (in German)

Lippert, Klaus. Detektion eines submarinen Aquifers vor der Küste Israels mittels mariner Long Offset Transient-elektromagnetischer Messung, PhD Thesis, Universität zu Köln, 2015.




The importance of offshore submarine fresh groundwater bodies as well as of submarine groundwater discharge (SGD) became commonly recognized in the recent years for groundwater management. The existence of submarine fresh groundwater bodies extending offshore to distances between a few meters to several tens of kilometers was reported all over the world and SGD was detected and studied also in the eastern Mediterranean, offshore Israel. The Mediterranean coastal aquifer of Israel is one of the main groundwater resources of the country. It has been exploited heavily and, as a result, the quality of water is gradually deteriorating. It is well known that the aquifer is grouped into four subaquifers, which were managed separately. The upper two sub-aquifers are known to be subjected to lateral seawater intrusion and to pollution from above whereas the lower ones are assumed to be, in places, blocked to the sea. For a long time, geoelectric and, particularly, geoelectromagnetic methods were leading geophysical techniques in solving various hydrogeological problems related to the characterization of groundwater salinity. This is due to a very close relationship, which exists between the salinity and electrical resistivity measured by the methods. In order to explore fresh groundwater below the sea the Long Offset Electromagnetic (LOTEM) method, which uses grounded lines (electric dipoles) as both transmitter and receiver antennae, is applied in the marine environment. The presented work is part of a Joint German-Israeli project, funded by the German Federal Ministry of Education and Research (BMBF) and the Israeli Ministry of Science, Technology and Space (MOST). The LOTEM measuring system from the Institute of Geophysics and Meteorology, University of Cologne is applied for the first time in the marine environment. Although marine Time Domain electromagnetic methods with a horizontal transmitter dipol are used by the oil-industry or other university working groups for similar targets, it was never reported, besides by the Israeli project partner Geophysical Institute of Israel, to be applied to such shallow waterdepths up to a maximum of 50 m. The main goal of this thesis is to detect the submarine aquifer and to examine its lateral dimension.