摘要
Groundwater scarcity in arid regions may hinder development plans and cause many inconveniences for the population and authorities. Saudi Arabia has limited groundwater resources stored in the sedimentary sequence of the Arabian Shelf. Some of these resources were classified as major aquifers, secondary and minor aquifers, and some were considered as aquicludes. The Jubaila Limestone is one of the secondary aquifers of Saudi Arabia. The main purpose of this paper is to evaluate the groundwater resources of the Jubaila Limestone in Riyadh area, with emphasis on groundwater quality. Groundwater was found to occur in fractures and within solution openings of the Jubaila Limestone at depths which range between 19 and 210 m. The transmissivity value was 1.7 × 10–3 to 7.2 × 10–3 m2/s;the storage coefficient was of 1.3 × 10–4. The electrical conductivity for collected water samples ranged between 831 and 7670 μS/cm. The major ionic relationships were Na > Ca > Mg and SO4Cl > HCO3. The groundwater evolves from NaCl dominated at the southern end of the study area, into Ca, MgSO4 water in the north. The main chemical process responsible of this variation was found to be dissolution of anhydrite and gypsum. The groundwater was not found suitable for drinking purposes but can be used by livestock and for some agricultural purposes.
Groundwater scarcity in arid regions may hinder development plans and cause many inconveniences for the population and authorities. Saudi Arabia has limited groundwater resources stored in the sedimentary sequence of the Arabian Shelf. Some of these resources were classified as major aquifers, secondary and minor aquifers, and some were considered as aquicludes. The Jubaila Limestone is one of the secondary aquifers of Saudi Arabia. The main purpose of this paper is to evaluate the groundwater resources of the Jubaila Limestone in Riyadh area, with emphasis on groundwater quality. Groundwater was found to occur in fractures and within solution openings of the Jubaila Limestone at depths which range between 19 and 210 m. The transmissivity value was 1.7 × 10–3 to 7.2 × 10–3 m2/s;the storage coefficient was of 1.3 × 10–4. The electrical conductivity for collected water samples ranged between 831 and 7670 μS/cm. The major ionic relationships were Na > Ca > Mg and SO4Cl > HCO3. The groundwater evolves from NaCl dominated at the southern end of the study area, into Ca, MgSO4 water in the north. The main chemical process responsible of this variation was found to be dissolution of anhydrite and gypsum. The groundwater was not found suitable for drinking purposes but can be used by livestock and for some agricultural purposes.
