So-called reclamation areas southwest of the Nile Delta, Egypt, depend almost exclusively on groundwater for irrigation of new agricultural land. We applied stable isotopes and noble gases to study the origin of the groundwater, and several environmental tracer methods (SF6 , 3H–3He, 14C) to determine its age. The stable isotopes clearly identify the Nile river as the main source of the water, and due to the change of the river’s isotopic composition in response to the construction of the Aswan High Dam, they also provide time information. The environmental tracers show that water recharged during the past 40 years is present only in wells close to surface water features.
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