Zambezi - Ecology

Ecology

Sewage effluent is a major cause of water pollution around urban areas, as inadequate water treatment facilities in all the major cities of the region force them to release untreated sewage into the river. This has resulted in eutrophication of the river water and has facilitated the spread of diseases of poor hygiene such as cholera, typhus and dysentery.

The construction of two major dams regulating the flow of the river has had a major effect on wildlife and human populations in the lower Zambezi region. When the Cahora Bassa Dam was constructed in 1973, its managers allowed it to fill in a single flood season, going against recommendations to fill over at least two years. The drastic reduction in the flow of the river led to a 40% reduction in the coverage of mangroves, greatly increased erosion of the coastal region and a 60% reduction in the catch of prawns off the mouth due to the reduction in emplacement of silt and associate nutrients. Wetland ecosystems downstream of the dam shrank considerably. Wildlife in the delta was further threatened by uncontrolled hunting during the civil war in Mozambique.

The transfrontier Okavango-Zambezi Conservation Park will cover parts of Zambia, Angola, Namibia, Zimbabwe and Botswana, including the famous Okavango Delta in Botswana and Mosi-oa-Tunya (The Smoke That Thunders, or Victoria Falls). It is thought that the cross-border park will help with animal migration routes and assist in the preservation of wetlands which clean water, as sewage from communities is a problem.

Funding boost for cross-border conservation project along the Zambezi in 2008. The Okavango–Zambezi Transfrontier Conservation project—which follows the Zambezi River and stretches across Angola, Botswana, Namibia, Zambia and Zimbabwe—has received a grant of €8 million from a German nongovernmental organisation. Part of the funds will be used for research in areas covered by the project. However, Angola has warned that landmines from their civil war may impede the project.