Planning for reuse of agricultural drainage water, for agricultural irrigation, was elaborated by the desire of the Egyptian government to use the water of the drain catchments rather than the use of isolated drain. El
Umoum drain project (West Nile Delta region) is planned for mixing drainage water with fresh water. The objectives of this study, therefore, were to evaluate the quality of the water of the drains of El Umoum catchments area and to calculate the water quality index (WQI) for the drains in this area.
Samples of water were collected in the years: 1989, 2000 and 2010 at three flow conditions: low flow winter
season (December), winter closure period (January) and high flow summer season (August).
The obtained results indicated high pollution of the main drains by inorganic and organic compounds. The concentration of total dissolved solid (TDS) had been increased in the drains with time proceeding and were higher in water collected in 2010 than in water collected in 1989 and 2000, and also increased with water flow from south to north direction. The lowest levels of TDS were recorded in water of Abu Hommos drain (average values of 1304 and 1408 mg/l in 1989 and 2000, respectively) and the highest levels were recorded in the water of El Umoum drain at Bab ElAbeed (average values of 4117 and 4200 mg/l in 1989 and 2000, respectively). The highest concentrations of COD were recorded in the water of Abu Hommos drain (average values of 56 and 68 mg/l in 1989 and 2000, respectively) and lowest levels were recorded in the water of El Umoum drain at Bab ElAbeed (Average values of 30, 34 and 30 mg/l in 1989, 2000 and 2010, respectively).
The concentrations of BOD5 were the highest in water of Abu Hommos drain (average values of 23 and 34 mg/l in 1989 and 2000, respectively) and the lowest values were in water of El Umoum drain at Bab ElAbeed (average values of 12, 15 and 13 in 1989, 2000 and 2010, respectively). It is clear, therefore, that the concentrations of TDS, COD and BOD5 were high and did not meet the requirements of the standard limits of the Egyptian law 48/1982. However, the concentrations of NO3 - , total Cd, Cu, Pb and Zn in the water of all drains of El Umoum catchments were within the standard levels of the law 48/1982.