Environmental Engineering Reference
In-Depth Information
two distinct seasons, with respect to rainfall - the hot summer period from October to
March with an average temperature of about 27ยบ C, and a dry weather for the remainder
of the year. Annual rainfall figures vary within a range of 440-1220 mm. Most of the
rainfall events are characterized by high intensities (AQUASTAT 2003). The mean
annual rainfall is about 800 mm.
2.1
Population growth trends
Harare is a sprawling city covering 570 km
2
and is the largest urban center of Zimbabwe.
The city has experienced a rapid growth since the attainment of independence in 1980.
Harare's population had increased from 656011 in 1982 to 1.2 million in 1992, and it is
now estimated to be above 2 million. According to the 1982 census, 33% of the urban
population in the country lived in Harare alone; by 1992 the figure had increased to 36%
and is likely to reach 40% before the year 2005, if the current trend prevails. The
expansion of the capital city, which followed the repeal in the late 1970's of the influx
control legislation that restricted the movement of the black population to the urban areas,
has been accompanied by an unmet housing demand. The expansion of the City has been
witnessed in the three major types of residential area developments - high, medium and
low density. The most critical and problematic areas are the high-density urban
developments. Sharp increases in the price of houses and rental accommodation have
followed the miss-match between housing demand and supply, especially since 1991,
after the relaxation of the rent control regulation. After the introduction of the Structural
Adjustment and Liberalization Program (ESAP), rentals in low-income residential areas
have increased by more than 300% between 1991 and 1996 and the urban influx has
compromised the quality of life through a resultant densification and general over
crowding (Potts & Mutambirwa 1991, Zinyama 1993). Drakakis-Smith & Kirell (1990)
have confirmed the trend of excess population density, where owners rented rooms for
coping with the housing shortage in Harare. This has had the effect of pushing the low-
income groups into informal housing and the consequent emergence and proliferation of
squatter (informal) settlements.
In general, two distinct patterns of overpopulation and undesirable urban development
practices could be differentiated. The first one consists of overpopulation of existing
high-density residential areas, which usually are provided with basic infrastructure. In
order to increase their income, owners are renting available rooms, or are building
additional shacks to accommodate as many tenants as possible. In Highfield for instance,
which is the second high-density residential area to be built, a local plan survey revealed
a total of 15 230 residential structures of which nearly half have been built without
permission (Rakodi 1995). This results in over loading of existing infrastructure facilities,
mainly the sewerage and drainage collection systems and the wastewater treatment
facilities. The other pattern, resulting from overpopulation, is represented by the
formation of informal settlements, which do not have any basic infrastructure, e.g. roads,
streets, water supply and sewerage. These two patterns are typical for the vast majority of
the countries in the Southern African region. In Harare, the predominant practice is the
first one, but in the latest years, the development of informal settlements is also
emerging.
