Dynamics of saltwater intrusion and submarine groundwater discharge in confined coastal aquifers: a case study in northern Israel

Deep Submarine Groundwater Discharge—Evidence From Achziv Submarine Canyon at the Exposure of the Judea Group Confined Aquifer, Eastern Mediterranean

“…corroborated the model predictions regarding DSGD, it seems likely that also salinization of water wells will occur within the next several decades, as suggested by the modeling study of Paldor, Shalev, et al (2019).…”

“…The estimated “sink” for the western Galilee hydrologic system is about 10 mcm/year (Kafri, ) and was previously suggested as northward leakage to the adjacent groundwater basin in Lebanon (Kessler & Kafri, ). The current study suggests that output of fresh groundwater from land to the ocean as DSGD could be this “missing sink.” Moreover, Paldor, Shalev, et al () modeled active seawater intrusion and possible salinization of water wells in western Galilee area (Figure ) that is linked to the DSGD by the connection between the terrestrial groundwater system and the sea through the confined JG aquifer. As this study corroborated the model predictions regarding DSGD, it seems likely that also salinization of water wells will occur within the next several decades, as suggested by the modeling study of Paldor, Shalev, et al ().…”

“…Annual rainfall ranges from 450 mm in the coast area up to about 800 mm further inland. A simplified geological cross section of JG, in which only the JG and the overlying aquitard are presented, is shown in Figure (based on our earlier study, Paldor, Shalev, et al, ). The Judea Group in the studied area has a flexural structure, synclinal off the shoreline, which changes into an anticline close to the shelf edge, from where the Judea Group subducts continuously basinward.…”

“…The current study suggests that output of fresh groundwater from land to the ocean as DSGD could be this "missing sink." Moreover, Paldor, Shalev, et al (2019) modeled active seawater intrusion and possible salinization of water wells in western Galilee area (Figure 1) that is linked to the DSGD by the connection between the terrestrial groundwater system and the sea through the confined JG aquifer. As this study (1) a confined flexural aquifer (JG), (2) seawater (red) intrusion through the aquifer's subsea outcrop exposed by the submarine canyon (ASC), (3) mixing of seawater with fresh groundwater (blue) that flows from the recharge area, (4) recirculation back at the upper part of the aquifer, and (5) seepage of recirculated water out into the deep sea as brackish water (orange) with salinity slightly lower than seawater.…”

“…It is hypothesized that this water type seeps at the bottom of ASC at the zone marked by the red curly bracket in Figure . According to geophysical sections (Paldor, Shalev, et al, and section ) at this zone, the top of the Judea Group aquifer (hereafter abbreviated JG aquifer) is cut and exposed at the sea bottom by the ASC.…”