Chapter 2: State and Trends


fluoride concentration in the groundwater of the Ethiopian Rift �alley reaches 98 milligrams per litre, 180 milligrams per litre in the Kenyan Rift �alley, and about 63 milligrams per litre in Tanzania, when the WHO drinking water standard limits for fluoride concentration is 1.5 milligrams per litre (Abiye 2010).


Gordon et al. (2013) observed that high population growth rates and associated impacts of reduced land cover and deforestation, coupled with global climate change, are affecting the ecological condition of the Volta River Basin. Increasing demand for water, in combination with reduced precipitation, has depleted stream flow by 50 per cent or more in some catchments (UNEP-GEF Volta Project 2013). There has also been an increase in the number of both large and small dams as a consequence of growing populations in settlements in Ghana, Benin and Burkina Faso. The construction of these dams has caused contamination, reduced water storage capacity and resulted in loss of aquatic ecosystems due to increased sedimentation, invasive aquatic species, increased proliferation of aquatic weeds, and downstream changes to the delta zone that affect estuarine processes and cause coastal erosion. The magnitude of sediment loads transported by rivers has important implications for ecosystem functioning through their influence on material fluxes, geochemical cycling, water quality, channel morphology, delta development and the aquatic ecosystems and habitats supported by the river. In Ghana, for example, the total fluvial sediment input to the coast has fallen from about 71 million cubic metres per year before 1964 (before the construction of the Akosombo Dam) to about 7 million cubic metres per year (Boateng et al. 2012), affecting the morphology and dynamics of the Volta delta area (Anthony 2015). The movement of sediments from soils exposed by deforestation and burning of farmlands, poor farming practices along steep slopes and river banks, overgrazing by livestock, intensive harvesting of fuelwood for energy, sand mining, and unplanned settlements, has removed land cover, increasing the storm-water runoff that carries sediments, nutrients and pesticides into rivers. For


Students using borehole in the town of Torit, South Sudan Credit: Shutterstock /John Wollwerth


example, it has been estimated that 50 per cent of the soil eroded upslope is deposited within the White Volta sub- basin in West Africa (Tamene et al. 2008).


Energy production requires large quantities of water. As long as the demand for energy (oil, gas and electricity) in Africa increases, the energy sector’s demand for water will also increase, exacerbating competition for the resource. Demands for freshwater and energy will continue to increase significantly to meet the needs of growing populations and economies, changing lifestyles and evolving consumption patterns, greatly amplifying existing pressures on limited natural resources and ecosystems (UNESCO 2014). Sparks et al. (2014) reported that South Africa’s energy company, Eskom, uses 2 per cent of the country’s national freshwater per year, which is equivalent to 0.6 per cent of annual Nile River flow or 0.3 per cent of Lake Victoria storage.


The impact of climate change on water quantity threatens Africa’s aspirations to have adequate power from renewable sources such as hydropower. This is true for dams that are


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