Modou A Sowe

Date of Award

4-2017

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Engineering

First Advisor

Dr. Mohamad Mostafa Ahmed Mohamed

Second Advisor

Ahmed Murad

Third Advisor

Chunmiao Zheng

Abstract

The control and management of seawater intrusion in coastal aquifers is a major challenge in the field of water resources management. Seawater intrusion is a major problem in the coastal aquifer of Wadi Ham, United Arab Emirates caused by intensive groundwater abstraction from increased agricultural activities. This has caused the abonnement of salinized wells and ultimately affected farming activities and domestic water supply in the area. In this study, the 3D finite element groundwater flow and solute transport model, FEFLOW was used to simulate pumping of brackish water from the intrusion zone to control seawater intrusion in the aquifer. The model was calibrated and validated with available records of groundwater levels and salinity distribution. Different simulation scenarios were conducted to obtain optimum pumping locations, rates as well as number of wells. It was found that pumping at a distance of 1500 m from the shoreline at 500m3/day using 16 installed wells is the optimum simulation. A comparison between scenarios of non-pumping and pumping was conducted. Results showed an increased in salt concentration in groundwater under the non-pumping scenario while it decreased under the pumping scenario. Under non-pumping scenario isoline 35,000 mg/l was observed to have intruded into the eastern southern part of the aquifer while maximum isoline observed for the same area under pumping scenario was 20,000 mg/l. This result showed an overall improvement in salt concentration in groundwater distribution and ultimately halted seawater intrusion in the aquifer.

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