Document Type

Article

Publication Date

1979

Abstract

The hydrogeologic map of Ajman is intended to provide valuable information on water resources for planning and management as well as for education and public information. The map illustrates areal distribution of aquifers, hydraulic heads, groundwater recharge and discharge areas and groundwater flow directions, Hydrogcologic map also reveals the variation in groundwater chemistry, quality and exploitation rates. Additionally, hydrogeologic maps include data on topography, geology and prevailing climatic conditions. Geomorphology of the Ajman Emirates is mountainous in Masfut, plain in Manama and coastal in Ajman. Rock lithology varies from Permian to Upper Cretaceous fractured Hawasina Complex ind Semail Ophiolites in Masfut to Quaternary eolian sand and gravel in Manama and Ajman areas. These rocks and sediments form unconfined aquifers, varying in nature, water chemistry and water quality. The groundwater is mostly fresh in Masfut, brackish in Manama and saline in Ajman, which has a direct impact on water use. The potentiometric surface maps of the aquifers within the study area indicate groundwater flow from the Northern Oman Mountains in the east towards the Arabian Gulf in the west. Local variations in the flow regime are related to lithological changes or water utilization patterns. Mathematical models and flow-net analyses indicate that the Quaternary sand aquifer within Ajman area is receiving 12,542 m' of recharge water from the east per day. Geographic Information Systems (GI$) map constructed from satellite image, digital elevation maps and field survey allow mapping areas of groundwater recharge, which are suitable for sustainable groundwater utilization without depleting aquifers or threatening water quality. The identification of these arcas is based on establishing the spatial relationship between several factors conducive to surface and subsurface water accumulation, infiltration and storage. Correlation of the final recharge/discharge potential map with satellite derived information on vegetation and soil moisture pattern confirm the location of suitable sites for agricultural development. The agricultural sector in Manama and Masfut areas is the main consumer of groundwater. Ajman Emirate has 691 farms covering 2,104 hectare (21.04 km²), which reccive irrigation water from wells tapping the Ophiolite and Quaternary sand and gravel aquifers. Despite the time limitation on the validity of hydrogeological maps, their continuous update can provide important water resources planning and management tool.

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