Pumping of Brackish and Saline Water in Coastal Aquifers: An Effective Tool for Alleviation of Seawater Intrusion Mohsen Sherif Civil and Environmental Eng. Department College of Engineering, UAE University United Arab Emirates 23 June 2008 Anvar Kacimov Department of Soils, Water and Agricultural Engineering, SQU University Sultanate of Oman

Factors Affecting Seawater Intrusion Seawater Intrusion into Coastal Aquifers Type of aquifer and its geometry and geology Water table and pizometric heads Natural rates of flow Irrigation and agricultural practices Pumping and recharge events Rainfall intensities and frequencies Seawater concentration and density Characteristics and parameters of the porous medium Geometric and hydraulic boundaries Tidal effects Earthquakes and vibrational effects Others Which of these factors are important?It depends on the problem

Inevitable process Pumping activities and intrusion rates Measures to Control Seawater Intrusion Reduce the pumping rates Reallocation of pumping fields Land use and agriculture practices Artificial recharge of groundwater Use of Scavenger wells Mitigation of Seawater Intrusion

Objective and Study Domain Examine the possibility of reducing seawater intrusion by pumping of saline (brackish) groundwater. n = 0.25, k x = m 2, k y = m 2, α = 5 m ρ f = 1000 kg/m 3, ρ s = 1025 kg/m 3 6 m (asl) 4 m (asl) 50 m 1000 m H 2 = 4 + k (50 –y) H max = 5.25 m 4000 elements (5.0 x 2.5 m) 4221 nodes

Tested Scenarios 140 m 105 m 277 m 196 m 6 m 4 m 5 m 4 m Run 1 Run 2 Steady State equi-concentration lines Steady State velocity vectors Reduced hydraulic head at the land side

6 m 4 m Pumping 86 m 3 /d: Steady state Q1 Run 3 Q1 Pumping 86 m 3 /d from two locations at land and sea side boundaries: Steady state Effect of Pumping

6 m 4 m Run 5 Q1 Q2 Q1 = 86 m 3 /d and Q2 = 130 m 3 /d Steady State equi-concentration lines

Pumping from a single well Basic Run Group 1 Run 1 Group 1 Run 2 Group 1 Run 3 Group 2 Run 4 Group 2 Run 6 Group 3 Run 7 Group 3 Run 8 Group 3 Run 9

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