Groundwater characteristic of the Najd aquifers,Oman, derived from isotope and hydrochemical signatures

摘要

Groundwater in the Najd region of Oman is more or less the only water resource for farming, housing, and animal feeding. Increasing efforts for a sustainable use of this groundwater needs to improve the knowledge about the origin, distribution, and recharge of the resource. The multi-component approach of the application of hydrochemical and isotope methods supports the complex understanding of the groundwater evolution in the four main aquifers A-D of the Najd region. The study reviews the hydrogeochemical character and a differentiated signature of the water isotopes P~(2P)H, P~(18P)O, and P~(3P)H in all Najd aquifers from A to D. It focuses on the groundwater chemical and isotopic behaviour, and the relationship between aquifers. The Najd groundwater is classified mainly as Na-Ca-Mg-SOB_(4B)-Cl, however, varying between the aquifers from A to D. The stable water isotopes P~(2P)H and P~(18P)O as well as tritium refer to the different recharge conditions in the past and recent infiltration processes including mixing of paleo-/sub-modern to recent groundwater between the aquifers. A hypothesis about origin and hydrochemical characteristic of groundwater from the Najd region is derived from the hydrochemical and isotope data from this study.