Recharge, timescale of groundwater flow, and geochemical evolution of the groundwater system in the Najd area, Dhofer Governorate, Sultanate of Oman

在这个项目中检验的研究假设说，阿曼西南部干旱的Najd地区的地下水来自多法尔山脉季风降水的渗透，通过wadis间接补给的贡献很小。由于过去的气候变化，与目前的补给相比，几千年前大部分地下水的补给率可能更高，使大多数地下水成为化石资源，因此是不可再生的资源。地下水的地球化学演化不仅受含水层向北倾斜的地下水流动过程中水-岩相互作用的控制，而且还受不同含水层之间的混合作用控制。拟议研究的主要目标是评估水平衡的关键方面，这将导致全面和可靠地了解纳伊德含水层的补给、流动和运输过程。提出的方法是水化学和同位素调查与基本水文和水文地质实地工作的最新结合。将使用水化学(主要和微量元素)和环境同位素(18O、2H、~3H、SF6、14C、13C、惰性气体)来获得关于地下水来源、年龄和流动路径的可靠数据。这些参数将与水文地质数据一起用于建立纳伊德含水层的综合概念性水文地质流动模型。

The research hypothesis examined in this project says that groundwater of the arid Najd area in southwestern Oman originated from infiltration of monsoon precipitation in the Dhofar mountain range with minor contributions from indirect recharge via Wadis. Due to past climate change most of the groundwater may have been recharged at higher rates several thousand years ago compared to current recharge making most of the groundwater a fossile and hence non-renewable resource. The geochemical evolution of the groundwater is not only controlled by water-rock interaction during flow of groundwater following the incline of the aquifer formations towards the north but also by mixing between the different aquifers. The main goal of the proposed study is to assess the key aspects of the water balance that will lead to a comprehensive and reliable knowledge about recharge, flow, and transport processes in the Najd aquifers. The methodological approach proposed is a state-of-the-art combination of hydrochemical and isotope investigations with basic hydrological and hydrogeological field work. Hydrochemistry (major and trace elements) and environmental isotopes (18O, 2H, 3H/3He, SF6, 14C, 13C, noble gases) will be used to get reliable data on groundwater origin, age, and flowpaths. Together with hydrogeological data these parameters will be used to develop a comprehensive conceptual hydrogeological flow model of the Najd aquifers.