This study combined gravity data from the Earth Gravitational Model (EGM2008) with
other data to better understand the spatial variations of the sedimentary cover and the
structural trends that affect groundwater flow in the Nubian Sandstone Aquifer System.
Our findingswere verified and evidenced by geological, geochronological, geochemical
data, and earthquake records: 1) The Uweinat-Aswan basement uplift, which runs eastwest,
partially isolates the Dakhla subbasin from the shallower northern Sudan subbasin,
and thereby impeding the south-to-north groundwater flow from northern Sudan
platform to the Dakhla subbasin; 2) A thickening of the sedimentary cover in the NE-SW direction
from the southern Kufra through the northern Kufra to theDakhla subbasin;
3) The sedimentary cover was found to increase from less than 500m in the south
(Northern Sudan and Uweinat region) to more than 6 km in the north (Mediterranean
coast); 4) A number of structural trends (NE-SW, N-S, E-W, and NW-SE) affecting the
region; 5) A large Pelusium megashear system that runs northeast to southwest makes it
easier for groundwater to flow from the Kufra subbasin to the Dakhla subbasin; 6) Along
the paths that groundwater takes, like fromSiwa toQattara and fromnorthwest Farafra to
north Bahariya, and along structures that run in the same direction as the flow, a
progressive increase in ³⁶Cl groundwater ages was observed; 7) It is a betterway to learn
about the hydrogeological context of large aquifers and figure out how to best manage
these underground water sources