139-Urban Runoff in Khartoum and its Effect on the Nile Water Quality.

Abstract

This paper infers upon the quality of urban runoff from Khartoum-Sudan (a typical urbanized community that lies on the banks of the Nile-system) and its effect on the Nile water quality. In addition, the correlation of storm water runoff contaminant load with the environmental management practices in the Khartoum area is discussed. Water quality parameters were measured at residential, commercial, agricultural, industrial and rural areas sampling points and mean concentrations were calculated for the rainy season August—October 2006. Weighted mean concentrations of BOD, COD, NO-3, TP, NH3 were found to be in the order of 45.8, 854.3, 33.5, 2.9, 14.1 mg/I respectively. The BOD and COD weighted mean concentrations for residential and commercial land uses in Khartoum 46.8, 511.9 and 1368.8 mg/i far exceeded the U.S. National Urban Runoff Program (NURP) mean EMC values of 10.0, 73.0 and 9.3, 57.0 mg/I respectively indicating poor environmental management of the urban Khartoum area. The average pollutants concentrations were found to decrease with the order of rainfall event during the year, decrease with increased rainfall amount, and increase with increased duration between events. During the month of Sep. the Khartoum state has contributed 164 Mm3/month of runoff to the main Nile constituting 0.824% of the total main Nile flow estimated using SCS method for dry conditions. The corresponding total loading rates of pollutants were found to be 12.2, 68.8, 1.7, 166.0% of the total main Nile average pollutant loading for BOD, NO-3, TP, NH3 based on the Global Environmental Monitoring System (Gemstat) average water quality data of the Blue Nile at Khartoum.