ASSESSMENT OF CURRENT AND PROJECTED WATER RESOURCES IN EGYPT AND THE MENA REGION USING SATELLITE-BASED HYDROLOGIC MODELS

Water resources are critical to both economic development and political stability. With Egypt’s population increasing from thirty million in the 1960’s to over eighty million today and expected to rise to over 110 million by 2035, the most critical issue is quantifying the current and projected water sources for drinking supplies and agriculture. Given the inaccessible terrain and lack of adequate hydrologic monitoring networks, it is difficult to assess the hydrologic systems in Egypt and much of the Middle East and North Africa (MENA).

We developed and applied an integrated approach to quantify the partitioning of precipitation into runoff, recharge, and evapo-transpiration in Egypt using hydrologic measurements extracted from satellite remote sensing. We constructed and successfully calibrated satellite-driven hydrologic models using TRMM-based precipitation, ASTER elevation, AVHRR soil moisture, and Landsat landuse and landcover data for the largest watersheds of Egypt from 1998-2013. Our earlier models were calibrated against streamflow measurements from Wadi Girafi; the calibrated parameters were then applied to ungauged basins using physical catchment descriptors. More recently, the models were further calibrated against recharge estimates extracted soil temperature probes. Climate change scenarios were performed using CO2 emission estimates from the IPCC fourth assessment report to project the change in precipitation and temperature and the subsequent impact on recharge in Egypt.

First-order estimates of the average annual modern recharge for the Nubian aquifer (13.0 x 10⁶m³/yr) and the shallow Alluvial aquifers in the Sinai Peninsula for the investigated watersheds (456 x 10⁶m³/yr) and the shallow Alluvial aquifers in the Eastern Desert (147 x 10⁶m³/yr) were computed using the SWAT (Soil Water Assessment Tool) model and public source global remote sensing data sets. These transferable procedures have successfully been applied to watersheds in Morocco, Turkey, and Kuwait, where preliminary estimates of the average annual recharge in the investigated watersheds are 5.2 x 10⁹m³, 2.9 x 10⁹m³, and 1.5 x 10⁹m³. Results provide a clearer picture of the water resources in Egypt and the MENA region as a whole.