Hydrogeology and hydrogeochemistry of some spring in the United Arab Emirates

الملخص EN

Despite the dry arid climate and lack of permanent rivers, u.

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$pring$ provide reasonable amounts of water which are used for various purposes.

However, little is known about their hydrogeology and ^drogerchemistry.

In this study, emphasis has been on the hydrogeology and hydrochemistry of salient u.

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springs; namely: Khatt (Ras Al-Khaimah), Siji (Al-Fujairah), and Bu Sukhanah (Abu Dhabi).

These springs are located in different rock types, at variable topographic elevations, within different drainage basins and along definite structural elements.

Results of this study showed that the 1984-1991 spring discharge rates ranged from 0.06x10؛ m3/y (Siji) to 2.50x10؛ m3/y (Bu Sukhanah), with little change during this period.

Based on these discharge rates and Meinzer’s classification, the studied u.

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springs belong to the second (Bu Sukhanah), fourth (Khatt north and Khatt south), and fifth (Siji) orders.

Rainfall-discharge corcelation showed that the discharge rates of Khatt springs are directly related to rainfall intensity.

In contrast, discharge rates of the Siji and Bu Sukhanah springs are not directly related to rainfall.

During the 1984-1991 period, the springs’ salinity has increased by 10% (Khatt south) to 50% (Bu Sukhanah) as a result of low rainfall and heavy groundwater pumping in springs recharge areas.

However, the increase of Bu Sukhanah spring’s water salinity with almost a triple increase in its discharge during the 1984-1991 period needs further investigation.

High spring-water temperatures (30°c, Siji; 39°c, Khatt north; 39.5°€, Bu Sukhanah; 41°c, Khatt south) can be related to the nature of groundwater flow circulation or radioactivity (especially, Bu Sukhanah spring).

?lotting the 1991 and 1994 chemical analyses of the waters of these springs on Piper’s diagram revealed that water types are sodium chloride and magnesium bicarbonate.

The relatively high HC03_ concentration (200-322 mg/1) in the water of Khatt springs suggests a relatively recent age, whereas the high S042- concentration (561-1862 mg/1) in Bu Sukhanah spring water suggests a relatively old age.

Comparison of water chemistry of each spring and the water chemistry of five shallow groundwater samples from the same area shows a good correlation between Khatt springs and shallow groundwater, in contrast to Siji and Bu Sukhanah springs that are distinctly different.

Calculated Sodium Adsorption Ratio (SAR) of springs water varies between 0.82 (Siji) and 15.01 (Bu Sukhanah), indicating that, except for Siji spring, water from the studied springs is unsuitable for irrigation of traditional crops.