1. Anner Paldor, Einat Aharonov, Oded Katz
Understanding steady-state Deep Submarine Groundwater Discharge: a case study in Northern Israel
Anner Paldor, Einat Aharonov, Oded Katz
EGU 2017, Vienna

2. Introduction - SGD can occur over different scales in the ocean.
Bratton, J. F. (2010). The three scales of submarine groundwater flow and discharge across passive continental margins.  J. Geol., 118(5),

3. Introduction
Deep Submarine Groundwater Discharge is ubiquitous, with important implications for Marine ecosystems, Fresh water budget, & Submarine slope instability.
The mechanism for steady state DSGD not previously understood.
Using numerical analysis of a case study, we suggest a new mechanism for steady-state DSGD.

4. Case study for DSGD: Achziv Canyon

5. Judea Group exposed in Achziv canyon at the hinge of the anticline
Geological map and
Kafri and Fleischer, 2003
EM-83-06
AS-04
Steinberg et al., 2011
ASHER-YAM-1
Seismic Hroizons
Top Saqiye
Base Saqiye
Top Judea
This structure is in good agreement with several other publications, among them:
1) Bakalowicz, M., El Hakim, M., and El-Hajj, A. (2008). Karst groundwater resources in the countries of eastern Mediterranean: the example of Lebanon. Env. Geol., 54(3),
2) Schattner, U., Ben-Avraham, Z., Lazar, M., and Hüebscher, C. (2006). Tectonic isolation of the Levant basin offshore Galilee-Lebanon – effects of the Dead Sea fault plate boundary on the Levant continental margin, eastern Mediterranean. Journal of Structural Geology, 28(11), 3)
Seismic Hroizons
Top Saqiye
Base Saqiye
Top Judea
Structural map of Top Judea Group

6. Using FeFlow to model flow in the JG
Aquifer
Confining units
X [km]
This is, in effect, a modified and more realistic Henry problem (structured aquifer, semi-pervious units etc.).
1st type BC: head = 0.025*|Y| [m] ; C=35000 [mg/l]
2nd type BC: qin= rain flux [m/d] ; C=0 [mg/l]

7. Salinity [mg/l]
Modeling predicts a smeared, shallow dipping, Fresh-Salt water Transition Zone in the aquifer.
500
Depth [m]
1000
1500 30 20 10
X [km]

8. Modeling predicts brackish, intense seepage from the outlet of the aquifer
0.89 m/d
150m

9. In contrast, when the flow is to a body of fresh water, almost no seepage occurs
0.89 m/d
150m

10. The intense seepage arises from a Gravity-Density Circulation Pump: recirculated SW constitutes most of the flow

11. Field validation of the model: research cruise along the Achziv canyon (20/12/2016)
5km
Google Earth
25 km

12. Detrended salinity profile along the canyon shows a plume of anomalous low salinity
Low salinity plume

13. Summary and Conclusions
The Judea group aquifer is exposed by the Achziv canyon, ~10 km offshore.
Numerical modeling predicts intense steady-state DSGD from it, even under low heads.
Seepage is driven by density differences & occurs by seawater recirculation.
A low salinity plume is measured in the canyon, in agreement with model prediction.

14. Thank you for your attention!