Environmental Isotope Study of the Well Field of the Sana'a Water Supply and Sanitation Local Corporation (SWSSLC) In Sana'a Basin-Yemen

Environmental Isotope Study Of The Well Field of The Sana'a Water Supply and Sanitation Local Corporation (SWSSLC) In Sana'a Basin-Yemen. The water in the deep aquifers of the Sana'a Basin has been investigated using chemical and environmental isotope techniques. To identify the Chemical and the Isotopic characteristics for the well fields of the Sana'a Water Supply And Sanitation Local Corporation (SWSSLC) which withdrawal the water from deep aquifers (Tawilah Sandstone and Volcanics).The Tawilah Sandstone and Volcanic Aquifers represent the main Aquifers in the Sana'a Basin.The chemical and environmental isotope study in Sana'a basin comes out with the following results: 1. The Hydrochemical characteristic in the Sana'a Basin differ from aquifer to another, according to the rock type or formation, It was found that the type of water in the Tawilah sandstone is dominated by Ca- Na- HCO3, while the water type Na-Ca- HCO3 found demonstrated in Volcanic Aquifer. Generally the Hydrochemical composition of groundwater from two aquifers are represent of mixture water. 2. The Groundwater of the deep aquifers for (Tawilah sandstone and Volcanics), indicates that its isotopic constitutes for a 18O is depleted and tend to be close from the slope 8 of global meteoric water line, which means that this water does not exposed to any evaporation processes, and infiltrated to the aquifers in a cold and humid climatic condition. It is also indicates that the recharge to the deep aquifers comes from the same source and same altitudes, and also there is a hydraulic contact between aquifers. 3. The δ 18O and δ 2H values of the groundwater samples from deep aquifers are reflect hydrological regime with limited present day recharge and storage of large volume of fossil ground water .the very low or non-existent Tritium3H concentration observed in groundwater also support this conclusion and indicate that the groundwater contains no water recharged in the last four decades. Which give sign that the current abstracted Groundwater represent fossils water (i.e. water is abstracted from the strategic storage). 4. The isotopic constitutes results for radioactive 14C for Groundwater indicates that it is old water with age range between 1 Ky to 10 Ky by Vogel's concept model., But for the well H7 it indicates that the age of this water is estimated as 1 K.y, this water is considered a recent water comparable with the others ages which exceed 3 K.years. (author)