Characteristics of an urban environment in the context of diffuse pollution control
Harare, the capital city of Zimbabwe, located in the Manyame River catchment basin, has been characterized, in terms of population growth characteristics, land use patterns and the water supply, sewerage and drainage systems. Specific attention has been given to the water quality of the Lake Chivero and tributaries, which receive the runoff from the city. A historic overview of the catchment water quality has been done, based on published data from previous research projects. Nutrients variations in urban drainage have been presented, based on data from the city’s monitoring program for the period 1995–2000. Results show a sustained trend of increase in the concentrations of phosphates and ammonia. Comparison with earlier studies shows that this trend has been reported since the 1980’s. The existing regulatory instruments and monitoring practice have been discussed with emphasis and implications with respect to diffuse pollution control and abatement, and corresponding recommendations for future development put forward.