Chapter 2: State and Trends


coastline measures 45 649 kilometres (Vafeidis et al. 2005). Bounded by the Mediterranean Sea, Atlantic Ocean, Indian Ocean and Red Sea, 33 of the region’s 48 mainland countries have a coastline, while six others are island nations (Brown et al. 2011). The region’s coastal and marine resources are important economic assets, providing fish, tourism services, trade access, and non-renewable resources such as minerals and gas. There are 320 coastal cities in Africa (UN-Habitat 2008), with associated high levels of economic activity, such as mining, oil and gas exploration, extraction and refining, and transportation. These economic activities attract large populations, and as a result, marine and coastal resources are prone to overfishing, pollution and coastal degradation.


2.3.2 Water quality and quantity The quantity of water available for a range of human needs is variable, depending on the climatic and geological setting. Africa’s main water consumer is agriculture, which often results in unwanted wastage through evaporation and


runoff. In regions where water is a critically limited resource, there is increasing awareness of the use of water-harvesting technologies in agriculture to overcome shortages during dry spells and droughts, including rainwater harvesting, floodwater harvesting and groundwater recharge (Box 2.3.1).


Owing to their easy accessibility, lakes, rivers and streams are the main recipients of pollution across Africa and the quality of the water is often compromised. These aquatic systems, used as an immediate source of water for large cities, may not be suitable for direct consumption and such water is either wasted or requires expensive treatment. According to UNEP (2015), nutrient pollution in rivers is caused by runoff from agricultural activities, sewage and atmospheric nitrogen deposition. Estimates, for example, show a 10-80 percent increase in total nutrients exported by rivers to coastal areas between the period 1970-2000 and projections of higher total loads of dissolved nitrogen and


Box 2.3.1: Water harvesting, examples


A commercial horticultural farm situated along the banks of the Athi River outside Nairobi, Kenya, harvests 60 per cent of its 300 000 cubic metres water requirement from rainwater.


Water harvesting from Charco dam, as well as a storage tank at the South Pare Mountains, Tanzania, is crucial for livestock watering in the region.


Rainwater harvesting at Sekkouma –Irzaine, Morrocco, and Kiffa, Mauritania, has proven benefits for farmers and the environment.


Roof to surface catchments, reservoirs and tanks are key sources of domestic and agricultural water supply in Botswana, Kenya, Mali, Tanzania and Togo.


Runoff irrigation, floodng, micro-basins and rooftop water catchment are common practices in Ethiopia. Sources: IRC 1990; Alem 1999; Kahinda et al. 2007; UNEP 2009


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