Preliminary assessment of the cocial, economic and environmental impacts of Water Hyacinth in Lake Victoria basin and status of control
The paper presents preliminary data collected in an assessment of the social, economic and environmental impacts of water hyacinth in the Lake Victoria Basin. A summary of the status of control and strategies for the future is given. The report draws on field observations made, studies through interviews of affected communities and organisations, personal communications and published reports by scientists in the region. Lake Victoria, the world’s second largest freshwater body, supports an estimated 25 million people living in the Basin, with an estimated gross economic product of US$3–4 billion annually, mainly from subsistence agriculture and fishing in Kenya, Uganda, Tanzania, and parts of Rwanda and Burundi. The multiple activities in the Lake Victoria Basin have increasingly come into conflict, thus making the lake environmentally unstable and increasingly inviting environmental threats, including infestation by water hyacinth, which has brought social, economic and environmental problems to the communities living in the Lake Basin since its first appearance in the Lake in the late 1980s and early 1990s. The maximum water hyacinth cover in Lake Victoria was reached between 1994 and 1995 when 80% of the shoreline in Uganda was covered with about 4000 ha of water hyacinth, there was about 6000 ha coverage in Kenya and about 2000 ha in Tanzania. In Rwanda and Burundi, tributaries feeding into River Kagera currently continue to discharge mats of water hyacinth into the lake at about 3.5 ha per day. The status as at June 2000 was slightly different, with scant water hyacinth in the Uganda side of the lake and much disintegrated and stunted water hyacinth in Kenya and Tanzania sides of the lake and the scene is now dominated by hippo grass. Impact assessments of water hyacinth have generally been subjective, with few quantitative outputs. However, over the last nine years or so, water hyacinth has had a negative impact on the organisations and communities in the Basin. Surveys have revealed negative social impacts including lack of clean water, increase in vector-borne diseases, migration of communities, social conflict and difficulty in accessing water points. Important economic impacts readily perceived by Basin communities have included reduced fish catches, increase in transportation costs, difficulties in electricity generation and water extraction, fewer tourists, blockage of irrigation canals and environmental impacts such as decline in water quality, water loss through evapotranspiration, siltation, increased potential for flooding and a decline in the diversity of aquatic life. Although water hyacinth has posed serious economic, social and environmental consequences, there is hope that the control strategies already adopted will continue to reduce deleterious impacts and allow sustained development in the Lake Victoria Basin. There is, however, a great need to undertake research to quantify the levels of damage, and the costs of control, loss of livelihood, disease, and disruption of normal operations caused by water hyacinth.
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