Impact of Pollution on the Quality of Water of Oued El Harrach (Algeria)

El Harrach wadi is one of the largest wadis that cross the plain of Mitidja. The current state of the wadi is calamitous, and its influence on the Algerian coast is disastrous since it became an open sewer; this wadi poisons the lives of local residents and has become a real problem for the whole commune of El Harrach and one of the factors degrading the water quality of the Bay of Algiers. In altitude, the pressures on the Oued El Harrach come mainly from the agricultural activity. At low altitude, these pressures are the result of human activity; they may be the result of population growth, the rapid expansion of urban areas, the development of agricultural activities and industrialization. Water quality is poor in all downstream stations. In summer, in the H9 station (Baba Ali town) where the degree of pollution is very high, the BOD₅ exceeded the limit, reaching a maximum of 238 mg/l. The results of the COD also indicate that the water quality is bad. The COD reaches a maximum of 407 mg/l, in summer at the H11 station (City of Baba Ali).