ABSTRACT
Basic principles and approaches to assess diffuse pollution from urban storm water have been presented. As an example of a pollution evaluation procedure, a case study on the storm water of two major drainage channels in the City of Harare has been done during the period 2002–2003, and results were compared to previous measurements. Results show pollution with respect to TP, TSS, TDS, ammonia, COD, Cd and Pb, and a relatively good correlation has been found between COD and Zn concentrations as dependant variables of TSS concentrations. Spatial variations, as a result of specific land use patterns, did not show a statistically significant difference, except for the contribution from an industrial area. A single storm event has been studied and results show a considerable difference between mean values and EMCs with respect to parameters associated with particulate material only. The development of an event-orientated monitoring program, which would allow more accurate determination of site-specific pollution concentrations, and the need to adopt uniform methodology of pollution loads estimation has been recommended, as well as the integration of storm water management into the process of water resources management at catchment level.
