Surface water resources are limited to Egypt's share of the flow of the River Nile. In accordance with terms of 1959 Nile water agreement between Egypt and Sudan, Egypt's present annual share downstream Aswan Dam is 55.5 billion m³. The High Aswan Dam, commissioned in 1968, provides over-year storage to guarantee regulated water supplies. This Nile Water discharge constitutes more than 95 % of Egyptian total water supplies.

The Nile enters Egypt at its southern boundary with Sudan and runs through a 1000 km long narrow valley which varies between 2 and 20 km in width. Then, it is divided at a distance of 25 km north of Cairo into two branches (Damietta and Rosetta) forming a delta resting with its base on the Mediterranean shores. The lengths of the Damietta and Rosetta Branches are about 250 km and 239 km, respectively. The delta expands from south to north about 200 km and its base is about 300 km long from Alexandria to Port Said.

Rainfall is typical of an arid region; very low, irregular and unpredictable. This means a few days of rain is distributed on the period from November to March in the North. The mean annual rainfall of 18 mm ranges from 0 mm/year in the desert to 200 mm/year in the north coastal region. Rainfall on the Mediterranean coastal strip decreases eastward from 200 mm/year at Alexandria to 75 mm/year at Port Said. It also declines inland to about 25 mm/year near Cairo and 1 mm/year at Aswan. Significant intensities of rainfall are recorded on parts of Red Sea coast. The most southern part of the country on the boarder with Sudan is marked with these phenomena. Intensities in the neighbourhood of 500 mm/year were observed in some years. The total amount of rain is equivalent to 1.8 billion m³ per year over the areas under consideration.

The groundwater aquifer underlying the Nile Valley and the Delta is entirely recharged and is dependent on deep percolation of irrigation water and seepage for the irrigation system. Some limited renewable and non-renewable groundwater within the Western Desert and Sinai are currently used and the potential for the future depends on economical feasibilities.

The Nile system below Aswan can be considered a closed system with a single input from the High Aswan Dam and five outlets, which are: Evapotranspiration, non-recoverable municipal and industrial consumptions, evaporation, agricultural drainage water to the sea, and non recoverable inland navigation water released to the sea. Using this concept, the valley and Delta groundwater extractions and drainage re-use would be considered as internal mechanisms to increase the system overall efficiency and not as added resources.

The exact nature and details of these inter-relations are not clear yet. A new factor that adds to the complexity of the issue is the water quality changes. These are subject to research studies now conducted by the National Water Research Center (NWRC) in Egypt.

Surface water resources are limited to Egypt's share of the flow of the River Nile. In accordance with terms of 1959 Nile water agreement between Egypt and Sudan, Egypt's present annual share downstream Aswan Dam is 55.5 billion m³. The High Aswan Dam, commissioned in 1968, provides over-year storage to guarantee regulated water supplies. This Nile Water discharge constitutes more than 95 % of Egyptian total water supplies.

Egypt has no effective rainfall except in a narrow bond along the northern coastal area where the average rainfall is 200 mm. The groundwater aquifer underlying the Nile Valley and the Delta is entirely recharged and is dependent on deep percolation of irrigation water and seepage for the irrigation system. Some limited renewable and non-renewable groundwater within the Western Desert and Sinai are currently used and the potential for the future depends on economical feasibilities.

The Nile system below Aswan can be considered a closed system with a single input from the High Aswan Dam and five outlets, which are: Evapotranspiration, non-recoverable municipal and industrial consumptions, evaporation, agricultural drainage water to the sea, and non recoverable inland navigation water released to the sea. Using this concept, the valley and Delta groundwater extractions and drainage re-use would be considered as internal mechanisms to increase the system overall efficiency and not as added resources. The exact nature and details of these inter-relations are not clear yet. A new factor that adds to the complexity of the issue is the water quality changes. These are subject to research studies now conducted by the NWRC in Egypt.