The newly developed DED-transmitter consists of two horizontal electrical dipoles that share a common central electrode which has one polarity, while the outer ones have the opposite polarity. Thus, the current in each dipole flows in opposite directions. The differential signal is recorded by electrical receivers at a certain distance. This feasibility study, realized along the beach of de Panne in Belgium, is the first land-based application of the DED system of its kind. The freshwater distribution has a thickness variation of 8–15m in a depth of up to 30m. 24 DED measurements were conducted at the beach at low tide, utilizing two 75m transmitter dipoles in an inline configuration parallel to the beach. Six transmitter locations were assembled parallel to the beach with a spacing of 50m along with four electrical receiver stations at different offsets. Additionally, 40 inloop TEM stations were measured. Previously performed 1D modelling studies suggested an interpretation of the DED Step-On signal as more suitable compared to the DED Step-Off signal. A joint inversion algorithm is for DED and TEM data was developed. Based on these results a freshwater distribution underneath the Belgian coastline is confirmed with a varying thickness between 8 and 30m.


Article metrics loading...

Loading full text...

Full text loading...


  1. Constable, S.C., Parker, R.L. and Constable, C.G.
    [1987] Occam’s Inversion: A practical algorithm for generating smooth models from electromagnetic sounding data. Geophysics, 52:289–300.
    [Google Scholar]
  2. Haroon, A.
    [2016] Development of Novel Time-Domain Electromagnetic Methods for Offshore Groundwater Studies: A Data Application from Bat Yam, Israel. Ph.D. thesis, University of Cologne.
    [Google Scholar]
  3. Hermans, T., Vandenbohede, A., Lebbe, L., Martin, R., Kemna, A., Beaujean, J. and Nguyen, F.
    , [2012] Imaging artifical salt water infiltration using electrical resistivity tomography constrained by geostatistical data, 438–439: 168–180.
    [Google Scholar]
  4. Lebbe, L.
    [1981] The subterranean flow of fresh and salt water underneath the western Belgian beach. Rapporter och meddelanden - Sveriges Geologiska UndersÃűkning, 27, 193–219.
    [Google Scholar]
  5. Marquardt, D.W.
    [1963] An algorithm for least-squares estimation of non-linear parameters. Journal of the Society for Industrial and Applied Mathematics, 12: 591–612.
    [Google Scholar]
  6. Vandenbohede, A., Van Houtte, E. and Lebbe, L.
    [2009] Sustainable groundwater extraction in coastal areas: a belgian example. Environmental Geology, 11: 85–94.
    [Google Scholar]

Data & Media loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error