Author(s): Christopher H. Magadza
Email (s): magadza.christopherhd@gmail.com
Institution or organization of origin: Retired
Country: Zimbabwe
Abstract
Harare, formerly Salisbury, was founded in 1890. It is the capitol City of Zimbabwe It is located in a sub humid tropical ecozone, at 17.900S and 30.800E. The water supply to Harare comes from the Manyame river and its tributaries. Salisbury was established on marshy area. As the settlement grew a series of reservoir were constructed beginning with Cleveland dam (910 ML) in 1913. Watershed area is about 2 227 km2 ranging in altitude between 1300 m and 1500 m. Mean annual precipitation range 750 mm to 900 mm. Mean maximum and minimum temperatures are 10.6OC 29.9OC Harare City sits on the wetland headwaters of its water supply. The city is 98 300 ha, of which 21,750 ha (22%) is wetlands Records of the Manyame River flow into lake Chivero indicate a decreasing annual inflow. Although since 1939 successive governments have outlawed developments on wetlands, wetlands loss in urban areas occurs at significant rates due to the government’s reluctance to enforce the various legal instruments protect wetlands for fear of losing political support. Sediment studies show that the lake has lost 20% water storage capacity Concurrently, the Municipality’s capacity for waste treatment has deteriorated, resulting in discharge of inadequately treated sewage into Lake Chivero. The fine mud sediments now store sufficient phosphorus to sustain hypereutrophic state for several years after rehabilitation of the sewage works.