MODELING THE HYDROLOGIC IMPACTS OF THE TUSHKA CANAL PROJECT ON THE NUBIAN AQUIFER (SW EGYPT) AND ON THE SALTWATER INTRUSION IN THE NILE DELTA

The Government of Egypt initiated the Tushka Canal project (1998-2002) to divert approximately 5 to 9 billion cubic meters of Nile River water per year, currently stored in Lake Nasser, to the Western Desert to develop new agricultural lands. We investigated the future effects of the Tushka Canal project on the Nubian Aquifer and on the saline water intrusion in the central delta.

A 2-dimensional groundwater flow model was built and calibrated against observed data by accounting for the transient recharge caused by intensive lake fluctuations during the calibration period (1970-2000). The simulation results indicate: (1) The recharge front from the lake is expected to advance northwestward at an average rate of 0.1-0.4 km/yr without posing flooding risks for the irrigation areas. (2) The pumping/injection rates expected in the project will cause no major impacts, except for the formation of some local cones of depression and ground water mounds. (3) Irrigation recharge will complicate the groundwater flow by introducing the modern lake waters and could potentially cause flooding and salinization in the vicinity of the proposed irrigation areas.

A two-dimensional density-dependent groundwater flow and solute transport model (FEMWATER; Lin et al., 1997) was used to simulate the effects of increased extraction of the Nile aquifer groundwater and decreased recharge resulting from the diversion of Nile water through the Tushka Canal on the salt water intrusion in the central delta aquifer. The current understanding is that extraction in the southern and central delta is less likely to produce major changes in salinity distribution. Our simulation results, however, indicate that the projected extraction could potentially increase the concentration of the total dissolved solids by up to 1000 ppm in the study area over the next ten years.