Combined time‐series resistivity and geochemical tracer techniques to examine submarine groundwater discharge at Dor Beach, Israel

Abstract

[1] A high-resolution, stationary geophysical and geochemical survey was conducted at Dor Beach, Israel, to examine the shallow coastal hydrogeology and its control on the exchange of submarine groundwater with the shallow Mediterranean Sea. Time-series resistivity profiles using a new 56 electrode (112-m long) marine cable produced detailed profiles of the fresh water/salt water interface and the subtle response of this interface to tidal excursions and other forcing factors. Such information, when ground-truthed with representative pore water salinities and formation resistivity values, can provide unique information of the extent and rates of submarine groundwater discharge (SGD). Time-series 222 Rn measurements of the adjacent coastal water column complemented these geophysical techniques and were modeled to yield integrated advective flow rates across the sediment/water interface, which at Dor Beach ranged from about 0 to 30 cm day À1 (mean = 7.1 cm d À1 ), depending on the tidal range. Such results suggest that the underlying hydrogeologic framework at Dor is favorable for substantial SGD. Extrapolating these SGD estimates across a 100-m wide coastal zone implies that the Rn-derived SGD rate would equal $7.1 m 3 d À1 per m of shoreline, and that the source of this discharging groundwater is a complex mixture of fresh groundwater derived from the upland Kurkar deposits, as well as locally recycled seawater.

Isotopic, geophysical and biogeochemical investigation of submarine groundwater discharge: IAEA-UNESCO intercomparison exercise at Mauritius Island

“…springs) or dispersed seepage. Since these isotope tracers integrate SGD fluxes over the scale of sampling, they have contributed to a better understanding of SGD dynamics, opposed to physical seepage measurements, which only constrain SGD fluxes on small, local scales Moore, 2006;Povinec et al, 2006aPovinec et al, ,b, 2008aSwarzenski et al, 2006;Cable et al, 2004;Weinstein et al, 2006;Stieglitz et al, 2008). …”

Groundwater and nutrient discharge through karstic coastal springs (<i>Castelló</i>, Spain)

“…In the Mediterranean Sea, a widespread existence of SGD via submarine springs has been identified along the coasts of Turkey, Syria, Lebanon, Israel, Greece, Italy, France, Spain, Algeria, Tunisia, Libya (Mijatovic, 2007). However, there are only a few local or regional studies on the quantification of karstic SGD fluxes in the Mediterranean carbonate basin, carried out in coastal areas of Italy (Moore, 2006a), Turkey (Bakalowicz et al, 2008), Israel (Swarzenski et al, 2006) and Spain .…”

Linking regional sources and pathways for submarine groundwater discharge at a reef by electrical resistivity tomography, 222Rn, and salinity measurements

“…In addition to numerical modeling, large-scale electrical resistivity (ER) imaging can fill this gap. While there are excellent examples of its application in SGD studies [Breier et al, 2005;Swarzenski et al, 2006], we present a regional yet high-resolution application in a carbonate reef fringing an island with no obvious surface drainage. We collected more than 30 km of intersecting ER lines over a 10 km 2 area over several days leading to a 3D ER map for the reef.…”