Managing coastal aquifer salinity under sea level rise using rice cultivation recharge for sustainable land cover

Study region: The coastal aquifer of Nile Delta, Egypt is used to develop the current study.
Study focus: Excess water from rice irrigation is a source of incidental recharge to mitigate
seawater intrusion. This paper numerically explores the optimal location of rice cultivations by
subdividing the delta domain into three distinct recharging regions (north, central and south).
Additionally, SEAWAT code was simulated under a combination of rice cultivation relocation and
sea level rise (SLR).
New hydrological insights for the region: The study findings revealed significant variations in salt
volume reduction depending on the location of rice cultivation in the delta. Placing rice cultivation
in the northern region resulted in the highest reduction of salt volume (19 %). In contrast,
locating the recharge in the central region yielded a salt volume reduction of 0.50 %, while rice
cultivation in the southern region produced a 15 % increase. Considering the projected SLR of 61
cm by 2100, there was an overall salt volume increment of 3 %. However, when accounting for
both SLR and rice cultivation recharge in the northern region, a substantial salt volume reduction
of 17 % was observed. The results demonstrated that incidental recharge by rice cultivation in
coastal aquifers is an effective method for enhancing saltwater intrusion control. Moreover, this
study improves our understanding of hydrological processes and expected responses in the delta
under future climate scenarios.