Seawater Intrusion Assessment and Mitigation in the Coastal Aquifer of Wadi Ham

The United Arab Emirates (UAE) typifies an arid environment with limited freshwater resources and harsh climatic conditions. Rainfall is scarce, random and can be regarded as an integral element of the water resources at UAE. Groundwater resources, although non-renewable, contribute by more than 50 % of the total water demand in the country. Due to the excessive pumping of groundwater to meet the agriculture demands, groundwater levels have declined in the coastal aquifer of Wadi Ham and the quality of the water has deteriorated due to the seawater intrusion problem. In this study, MODFLOW and MT3D are employed to simulate the groundwater flow and assess the seawater intrusion problem in Wadi Ham and possible mitigation measures. The flow model was calibrated and validated through comparisons with two independent sets of data collected over periods of 5 and 11 years, respectively. The results of the transport model were calibrated against available groundwater concentrations at some locations. The developed model is then used to study the effects of pumping and artificial recharge on seawater intrusion. Results indicated that reducing the pumping from Khalba well field will retard the seawater intrusion in the southeastern part of the aquifer. Applying artificial recharge through a surface basin of 100 × 100 m at a rate of 1 m/day will cause equi-concentration contour line 10,000 mg/l to retreat about 1.25 km towards the coast within a period of 12 years.