Environmental Engineering Reference
In-Depth Information
CHAPTER 5
Diffuse pollution in high-density (low-
income) urban areas
R. Hranova
ABSTRACT: Diffuse pollution problems typical for low-income
residential areas have been discussed in terms of sources, monitoring,
regulation and control. The problem has been illustrated by a case study,
where the water quality of a natural stream was assessed to evaluate the
impact of runoff from storm water generated in low-income residential
areas in Harare, Zimbabwe during the 2001-2002 wet season. Results
show considerable pollution load with respect to TP, ammonia, Fe and Pb.
An evaluation of pollution fluxes along the stream, generated by different
types of land use patterns within the study area, showed that the major
flux is associated with the dumping of solid waste along the streambed.
The analysis of appropriate practices for monitoring, control and
abatement of diffuse pollution in such areas is presented and emphasis is
made on the need to implement source control and pollution prevention
measures, and also to incorporate community education and public
involvement activities as part of pollution abatement programs.
1 INTRODUCTION
The characteristics of low-income urban developments in African countries have
followed some common patterns, connected to the general economic and social
environment. The development pattern, described with respect to Harare, could be
accepted as similar to other countries in the region as well, although specific flavor and
national characteristics and conditions would lead to differences in each specific case.
The link between the economic and social conditions and the pattern of urban
development should not be underestimated. In a number of cases, problems, associated
with the economic and social status of the society will be reflected in the landscape of
urban development schemes and would be closely associated with problems in water
resources management, as well as, undesirable public health and environmental impacts.
In Harare, during the 1980's, low-income residential areas were established with
uniform houses erected. The standard plot size was 324 m 2 , though some earlier schemes
utilised smaller plots (Rakodi 1995). However, pressure on space and utilities in these
areas, have led to a situation, where many more people often occupy the houses that were
originally designed for one family. In 1990, the number of illegal buildings had
increased, with the average number of informal buildings per plot variously estimated
between three and six. In Highfield for instance, which is the second low-income
 
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