3D Paleohydrogeological modelling of the Nile Delta

The Nile Delta in Egypt is a heavily populated area with high agro- and socio-economic
importance for Egypt. Though its lands are traditionally irrigated with surface water from the
Nile, the discharge of this river is reduced due to the building of large upstream dams, such
as the Aswan dam in Egypt (1970), the Merowe dam in Sudan (2011), and possibly in the
future the Grand Ethiopian Renaissance Dam in Ethiopia (under construction, estimated to
finalized end of 2018). This reduced surface water availability will probably lead to an
increased use of groundwater for irrigation. Adding to this stress on the groundwater system,
there is a strongly growing population which further amplifies extraction rates. Furthermore,
there is the estimated sea level rise. These stresses will cause the country to increasingly rely
on groundwater in the near-future. Therefore, an assessment of the current and future status
of the groundwater resources is critical to safeguard these precious resources for the coming
generations.
Several studies found that the area is vulnerable to salt water intrusion (e.g. Kashef, 1983;
Sefelnasr and Sherif, 2014) due to the shallow topography of the area and the high
transmissivity of the aquifer. Furthermore, hydrogeochemical measurement campaigns have
shown the strong influence of paleohydrogeologic processes on the current groundwater
salinity distribution (Geirnaert and Laeven, 1992; Barrocu and Dahab, 2010; Geriesh et al.,
2015). However, the previous hydrogeological models created for this area ignored the
influence of the paleohydrogeology, likely due to computational limitations, even though
some studies show a paleo reconstruction increases our understanding of the groundwater
system considerably (Tran et al., 2012; Delsman et al., 2013; Larsen et al., 2017; Vallejos et
al., 2017). In this study, we model the complete Nile Delta Aquifer in 3D over several
thousands of years. To tackle the computational burden this model created, we use the new
iMOD-SEAWAT code (Verkaik et al., 2017), that allows parallel computation on a super
In this presentation, we show the results of our efforts and compare these to a database,
compiled of data from the published articles. The influence of paleohydrogeological
circumstances and the (uncertain) lithology is shown.