Groundwater plays and will continue to play a critical role in satisfying water requirements for Saint Katherine and Feiran Oasis. Thus, sustainable groundwater development and presentation of groundwater quality should receive priority attention. Environmental impacts include both human activities and natural phenomena, but human activities could impair groundwater quality and contribute to maximum damage through over-exploitation and irrational use. The problem of groundwater quality and quantity have been intensified during the last few years in response to ever-increasing population.
The objective was to assess the impact of urbanization on recharge and groundwater quality. New sources of recharge are developed within urban areas, including septic tanks, and intensive irrigation of domestic gardens. The quantity of recharge depends up on the density of urban development, and the amount of water imported from external sources. A continuous decline of groundwater levels in wells indicates that the aquifer is subjected to a continuous intensive exploitation. Reduction of groundwater withdrawal is recommended to avoid the deficit in water supply and deterioration in water quality.
The hydrochemical compositions of water samples collected from the populous areas are characterized by high ionic concentrations of different ions, dominance of chloride and sulphate ions and low bicarbonate content. However, undesirable levels of chloride and sulphate ions were above the recommended levels. The elevated chloride concentrations in water may be indicative of mixing from higher chloride water, while elevated sulphate concentrations are attributed to the oxidation of organic and inorganic sulphide in soil profile. Nitrate-N concentrations are significantly higher in urban area (>1 ppm) than the non-urban sites, this is attributed to the microbial degradation of organic nitrogenous material including human and animal wastes as well as fertilizers used in domestic gardens. High concentrations of trace metals are noted in groundwater at dense populated areas. The results of bacteriological analyses show that only 11 wells are free of total Coliform and E. Coli type, these wells are located outside the populated areas. The presence of such bacteria affirms the presence of faecal pollution. Accordingly, the groundwater in populous areas should chemically treat before drinking. It is vital that a groundwater quality monitoring program be established as a matter of priority.
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