A cost-effectiveness evaluation of water hyoncith control methods: The case of Lake Kyoga and victoria Ecosiptems in Uganda.

The water hyacinth was first reported on Lake Kyoga in 1988. Given its high proliferation rate it has spread to cover about 70,000 and 20,000 hectares on Lakes Victoria and Kyoga, respectively. It has inflicted enormous negative effects that include: increased evapo- transpiration that has reduced the water table; physical obstruction of water transport means loss in quality of fish and other products leading to reduced incomes: increased operational costs attached to fishing activities resulting from loss of nets and boat engine breakdowns; reduced fish reproduction; and being a breeding ground for many disease-causing organisms. These effects have in turn affected the national economy; the environment and the health status of lakeshore residents and have resulted in its condemnation. Four control methods, namely, biological, chemical, manual and mechanical have been tried in Uganda at different sites. Comprehensive economic data on costs and effectiveness of the four methods are lacking. Given the limited resources at our disposal it is unjustifiable to undertake control of the weed without evaluation of the most cost effective strategy. This study was undertaken: to conduct environmental economic analyses and make comparisons among the four control methods, to make simulations of potential combination of the four methods and undertake sensitivity analysis and to develop an analytical procedure that can guide policy makers on deciding the best control strategy. Findings indicate that mechanical control method is the most cost effective with a cost-effectiveness (C:E) ratio of 0.016. This is followed by the manual, biological and chemical control methods with cost-effectiveness ratios of 0.116, 0.208, and 0.299, respectively. These ratios suggest the amount of money ( in US dollars ) required to clear a square mere area per hour. The mechanical method is, therefore, recommended for use in combination with manual methods in a ratio as close to 4: 1 as possible. This is in the interest of effective control and creation of some employment opportunities. This scenario would require about US $32 millions to undertake full-blown achievement. This is equivalent to US $ 108,000 per month. Finally, more pragmatic policy intervention and further research are necessary to evaluate use of the weed in animal feed formulations, biogas digesters, mulching and paper industries,