The Impact of Environmental Change and Water Conservation on Dryland Groundwater Resources in Northern Egypt: Modeling Aquifer Response Using Sparse Data

Abstract

<p>Wadi El Naturn, located in the Western Desert in northern Egypt, has been subject to significant groundwater degradation since the 1990s, attributed primarily to agricultural development. Information required to diagnose the drivers of groundwater degradation and assess management options in dryland environments like Wadi El Natrun is however, frequently sparse. This research presents an approach for modeling the impacts of dryland environmental change on groundwater in the context of sparse data. A focus is placed on understanding the potential impacts of conservation strategies in the context of climate change. Water use, hydrostratigraphic and groundwater flow data were collected from literature, monitoring records, satellite imagery and a survey of local landholders. MODFLOW-NWT was used to model the multi-layer aquifer system, and algorithms were developed in R to create realizations of groundwater recharge, and well-pumping at a monthly time-step from 1957 to 2011. The model was deemed to be reasonably capable of capturing the cumulative impact of environmental change over this historical period. A risk assessment approach was then used to assess the impact of climate change and conservation-focused management scenarios on groundwater locally over a 50-year future planning horizon. The optimization of irrigation systems and increased cultivation of drought/salt tolerant crops have the potential to significantly reduce the risk of groundwater depletion compared to an across-the-board 20% water use reduction scenario. The influence of groundwater pumping also outweighed that of climate change, and the most vulnerable water users/ecosystem were found to be the most exposed to groundwater degradation.</p>