Natural Springs: Hydrogeology, Hydrogeochemistry and Therapeutic Value

Abstract

This chapter discusses the hydrogeology, hydrochemistry and the therapeutic value of permanent UAE springs, e.g., Khatt (Ras Al Khaimah), Maddab (Fujairah) and Bu Sukhanah (Abu Dhabi). The springs are controlled by geologic structures, discharge of various rock types and their location at particular elevations.

Results of this study showed that the 1984–1991 spring discharge rates ranged from 0.06 million m³ (Mm³/year) (Maddab) to 2.50 Mm³/year (Bu Sukhanah), with little change during this period. Based discharge rates , the sequence of the UAE springs in descending order is: Bu Sukhanah (second; discharge 2.5 is m³/s), Khatt north and Khatt south (fourth; discharges are 0.51 and 0.69 m³/s, respectively) and Maddab (fifth; discharge is 0.31 m³/s). The rainfall–discharge correlation showed that the amount of flow of Khatt springs is directly proportional to rainfall intensity. In contrast, the discharge rates of the Maddab and Bu Sukhanah springs are not directly related to rainfall intensity.

Heavy groundwater exploitation during the period 1984–1991 appears to be the main cause of the increasing salinity of springs water, however, the increase of the salinity of the Bu Sukhanah spring’s water, with almost a triple increase in its discharge during the period 1984–1991, needs further investigation. High spring-water temperatures (30 °C, Maddab; 39 °C, Khatt north; 39.5 °C, Bu Sukhanah; 41 °C, Khatt south) can be related to deep groundwater circulation or radioactive decay at depth, as in the case of Bu Sukhanah spring.

Plotting the 1991 and 1994 chemical analyses on Piper’s diagram revealed that the springs’ water types are the chloride of sodium and bicarbonate of magnesium. The sulphate (SO₄ ²⁻ = 561–1862 mg/L) water of Bu Sukhanah spring (SO₄ ²⁻ = 561–1862 mg/L) suggests older age than the bicarbonate (HCO₃ ⁻ = 200–322 mg/L) water of Khatt springs.

The calculated SAR of the water of the studied UAE permanent springs decreases from 15 in Bu Sukhanah to one at Maddab Spring, showing that springs’ water is generally unsuitable for irrigation of conventional crops . However, the water of all UAE springs has a therapeutic value because of their warm water and high sulphur content.