Groundwater Quality Management in the Middle Nile Delta Utizlizing Environmental Isotopes and Solute Transport Modeling

In the present study, groundwater pollution in the central part of the Nile Delta is investigated. Natural chemical constituents and some contaminants of shallow groundwater and their distribution through the whole region of the studied area are investigated. A combination study of laboratory and numerical modeling are utilized.

Numerical modeling for governing equations describing advective-dispersive transport with multi rate mass transfer is utilized employing FDM. A three dimensional finite difference groundwater model MODFLOW is used to deal with the hydrodynamics of the flow through porous media. A groundwater solute transport simulator MT3DMS, which can be communicated with MODFLOW through data files, is utilized to solve the problem of contaminants transport and the change of their concentration with time.

Field measurement and experimental works through 60surface and groundwater samples were collected from the study region. The collected samples were analyzed in Central Laboratory of Environmental Isotope Hydrology, ENRRA. Stable isotopic techniques (Oxygen-18, Deuterium) were used to investigate the recharge sources, and Nitrogen-15 technique was applied to help tracing sources and fate of nitrate contamination found in collected water samples.

The analysis indicated that vulnerability of the water resources to pollution is mainly related to the use of excess fertilizers (NO₃), the growing industrial activities, and sewage effluent. The sources for the higher nitrate concentration appears to be mixing with sewage or manure and ammonium phosphate fertilizer. Scenarios for groundwater remediation in Birma village employing extraction wells are presented.

Keywords: Groundwater contamination, numerical modeling, field experimentation, environmental isotopes, ¹⁵N , MODFLOW, Nile Delta.