Time Scale of Water-Rock Interaction Processes in the Fresh-Saline Water Interface of Coastal Aquifers 1 Department of Geological and Environmental Sciences, Ben Gurion University, Beer Sheva, Israel 2 Geological Survey of Israel, Jerusalem, Israel 3 Institute of Earth Sciences, Hebrew University, Jerusalem, Israel Amos Russak 1,2 , Orit Sivan 1 , Yoseph Yechieli 2 and Boaz Lazar 3
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Time Scale of Water-Rock Interaction Processes in the Fresh-Saline Water Interface of Coastal Aquifers
Time Scale of Water-Rock Interaction Processes in the Fresh-Saline Water Interface of Coastal Aquifers. Amos Russak 1,2 , Orit Sivan 1 , Yoseph Yechieli 2 and Boaz Lazar 3. 1 Department of Geological and Environmental Sciences, Ben Gurion University, Beer Sheva, Israel - PowerPoint PPT Presentation
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Time Scale of Water-Rock Interaction Processes in the Fresh-Saline Water Interface
of Coastal Aquifers
1Department of Geological and Environmental Sciences, Ben Gurion University, Beer Sheva, Israel2Geological Survey of Israel, Jerusalem, Israel3Institute of Earth Sciences, Hebrew University, Jerusalem, Israel
Amos Russak1,2, Orit Sivan1, Yoseph Yechieli2 and Boaz Lazar3
http://water.usgs.gov/ogw/gwrp/saltwater/fig2.gif
Fresh-saline water interface (FSI)
1. Global sea level change.
2. Big sea storms.
3. Over exploitation of groundwater.
4. Seasonal changes in groundwater flow rate.
5. Tide. (?)
Changes in the FSI can happen due to:
Research Goals
• Identifying seasonal and diurnal controls on the chemical composition of water at the FSI.
• Quantifying the time scale and the chemical processes in the FSI from field observations and laboratory simulations.
(Netanya)
Research Area • Poleg Well located 70 meters from the shore.
• Poleg well depth is about 45 meters and perforated all along the length of the pipe.
Poleg
Poleg Well
Mediterranean
Sea
1) Seasonal electrical conductivity profiles.
2) Seasonal high resolution (15cm) chemical profiles by multi-layer-sampler (MLS). Equilibration with groundwater is less than 1 month.
3) Diurnal chemical profiles by 3mm diameter pipes and peristaltic pump. Sampling water was done from 6 depths every 2 hours for 28 hours.
Field Methods
MLS rodMLS Cell
Ion Exchange Simulations in the LaboratoryI. A column was filled with sediments
from the research area.
II. The column was saturated with local fresh groundwater.
III. Seawater was pumped through the column in three experiments using different flow velocities. Experiment are somewhat similar to those of Appelo, with addition of other parameters.
IV. The column was flushed with freshwater after each salinization experiment.
5 experiments
15
20
25
30
0 20 40 60Electrical Conductivity (mS·cm-1)
Dep
th (m
)
20
25
30
0 10 20 30 40 50 60
DecemnberJanuaryFebruaryMayjuneJulyseptember
The FSI zone moves vertically.
January
July
Field Results
0
20
40
60
80
100
120
140
0 100 200 300 400 500 600 700
Most of the results are on a simple mixing line between fresh water and saline water.