Ostrich and flamingos, Lake Nakuru, Kenya
M&C Denis-Huot/Still Pictures
A further environmental issue concerning the freshwater resources of eastern Africa is pollution from domestic, agricultural and industrial sources. Low levels of water supply and sanitation, and overburdening of municipal services, create situations where untreated sewage is discharged directly into watercourses, particularly in areas surrounding informal settlements. For example, in Mombasa, the domestic sewerage system was designed to serve about 17 per cent of the current population. The outfalls for both domestic sewage and stormwater run-off are located in the Kilindini and Tudor Creeks, and sludges from septic tanks and pit latrines are usually disposed of at the Kibarani dumpsite on the shores of Makupa Creek (UNEP 1998).
Poor agricultural practices contribute to the pollution of freshwater sources in two ways. Firstly, the increasing use of agrochemicals contributes to the pollution of both surface water and groundwater, through run-off. These chemicals either cause eutrophication (by increasing the nitrogen and phosphorous loads in water bodies), or are toxic to flora and fauna. Unsustainable farming practices and overgrazing increase the susceptibility of the soil to erosion. Increased sediment loads in rivers, in turn, contribute to siltation in dams and lakes, and the smothering of habitats, flora and fauna. Lake Victoria, for example, has become the recipient of increased concentrations of nitrogen and phosphorous, washed down from the surrounding plantations of tea and coffee. This has led to the invasion and rapid domination of the water hyacinth, Eichornia crassipes, which has formed dense mats, blocking navigation channels and choking boat engines. Other adverse impacts of the weed include modification of aquatic and wetland environments, through changing the concentrations of nutrients and dissolved oxygen, as well as reducing the light penetrating below the surface of the lake and releasing toxins. It also reduces the quality of water for drinking and domestic use, and provides an ideal habitat for disease carriers, such as mosquitoes. The Lake Victoria Environmental Management Programme is implementing biological, chemical and mechanical means of controlling the spread of the weed, and the Kisumu Innovation Centre-Kenya (KICK) has initiated marketing a number of crafts made from the weed (Olal, Muchilwa and Woomer 2001).
In 2001 Lake Nakuru and Lake Bogoria in Kenya experienced large numbers of deaths among the flamingos for which the lakes are famous. Pollution by heavy metals is suspected to be the primary cause of these deaths, resulting from contamination of the lakes by sewage, industrial effluent and organochlorines, which are present in agricultural run off
In 2001 Lake Nakuru and Lake Bogoria in Kenya experienced large numbers of deaths among the flamingos for which the lakes are famous. Pollution by heavy metals is suspected to be the primary cause of these deaths, resulting from contamination of the lakes by sewage, industrial effluent and organochlorines, which are present in agricultural run off (Environment News Service 2001). Industrial developments, particularly in urban centres and along the coast, have inadequate or expensive wastewater treatment facilities and, therefore, discharge of effluents directly into rivers and estuaries is common. The growing level of industrialization in greater Mombasa, for example, is causing considerable concern as a result of effluent discharge. Complex organic compounds and heavy metals may be contained in effluents and spillages from commercial industries and textile mills, which are located along the coast and banks of the Mombasa, Kilindini, and Port Reitz creeks (Mwangi and Munga 1997). A decline in the quality of freshwater creates even greater stress for water supply schemes. It can also limit industrial, domestic and agricultural water use, and it contributes to the prevalence of waterborne diseases.
Responses aimed at improving water quality and at mitigating the environmental impacts of poor quality water include the promulgation by several countries in East Africa of water quality standards and effluent controls. A Water Action Plan, providing a framework for the protection and development of Uganda's water resources, was prepared in 1994, based on the guiding principles of IWRM established at the United Nations Conference on Environment and Development (UNCED) in 1992. Uganda's Water Statute, incorporating many of the recommendations from the Water Action Plan, was promulgated in 1995, and regulations for the control of Water Resources, Water and Sewerage and Wastewater Discharges were issued in 1998. A draft National Water Policy is currently being reviewed prior to submission to The Ugandan government for approval (NEMA 1999). Wetland rehabilitation is also underway, in order to improve water quality and ecological functionality (See Box 2e.6).
|Box 2e.6 Wetland rehabilitation in Uganda|
|Source: NEMA 1999|
Ethiopia's water supply and sanitation sector shows an encouraging participation of communities, for example, through the contribution of beneficiary communities in the development and construction of water supply schemes and sanitation facilities (WHO/UNICEF 2000). Under the Africa 2000 initiative, launched in 1996, a study on low-cost latrine technology options was carried out in 1997, and a study on the impact of water and sanitation-related diseases on development is also nearly complete. Several health education trainers have completed their training and are being deployed.
Kenya's government has formulated a comprehensive water supply, demand and management policy, which was approved by the government in 2001. The policy outlines methods to improve water supply, methods for regulation, pricing and ways to enlist the participation of other stakeholders.