World Bank Reports Discloses Serious Environmental Damage from Tanzanian Dam

Elisabeth F. Olsen
Thursday, May 10, 2001

The Lower Kihansi hydropower project on the Kihansi River in Tanzania is causing significant environmental damage, a newly released World Bank report reveals. The Bank's Environmental Review states that the project is destroying a unique ecosystem and eradicating several endemic species. The report is causing worries among project donors, who fear the project may violate their own guidelines, as well as the international Convention on Biological Diversity.

The Tanzania Country Director of the World Bank, in cooperation with the Africa Region Environment Group, decided to carry out an environmental review after the scientific community and NGOs expressed concerns that the dam's current operation would lead to severe and possibly irreversible species losses in the Kihansi Gorge.

The180 MW dam, which officially began operating this July, destroyed an 800–meter–high waterfall, brought development to a protected natural area, and directly affected about 22,000 villagers. Financing for the US$275 million project included a $123 million IDA loan (IDA is the World Bank's lending agencies for the world's poorest countries), $59m from Norway, $29m from Sweden, and $32m from the European Investment Bank.

The environmental review states that drying out of the river's wetlands from reduced water flow is seriously threatening the Kihansi spray toad and two rare plant species, both of which are endemic to the Kihansi Gorge. These species will go extinct if adequate mitigation plans are not carried out, according to scientists. Tanzania has ratified the international Convention on Biological Diversity, which means it has committed to conserving endangered species.

The World Bank report describes three alternatives for mitigating the damage from Lower Kihansi Dam, none of which is likely to stop the extinctions. The first option is to do nothing. The second option is to implement captive breeding of the spray toad, but the report says that the risk of extinction will remain very high. The third option is to increase the water levels released from the dam. Even if this option is chosen, the threat of extinction is still high.

Poor Planning
The environmental problems are not surprising. The hydropower plant is situated in the mountainous Rufiji Basin, long known to hold unique ecosystems and high biodiversity. Even today, some of its ecosystem types and species of flora and fauna are yet to be identified or classified. Proper environmental impact assessments were therefore of high importance for evaluating the dam. But project environmental evaluations have been defective from the beginning.

The Lower Kihansi Hydropower Project was initiated in 1990 by the World Bank and the Tanzanian government. The Bank investigated two dam alternatives and a natural gas project. The feasibility study led to the decision to pursue Lower Kihansi Dam. The environmental assessment only covered the most basic requirements, and only analysed impacts on habitat inundated by the reservoir. The area downstream of the gorge was not taken into consideration, and neither water rights nor dam safety was mentioned. The report did not identify any potential ecological impacts on the downstream Kihansi Gorge.

The Bank's Board of Directors approved the project in 1993. The Norwegian aid agency NORAD was asked to join the project in 1994. NORAD's technical review team found the World Bank environmental assessment of such poor quality that it decided to finance an Environmental Impact Assessment (EIA). This EIA was the subject of a 1995 public hearing in Norway, at which Norwegian scientific experts expressed several concerns, including the inadequacy of the report's data, lack of adequate water–discharge plans, lack of management plans, and the lack of consultation with local people. Many recommended that NORAD not support the project. The Norwegian Water and Energy Directorate nevertheless recommended NORAD support the project under the presumption that further environmental studies would be carried out.

During the new environmental studies, researchers discovered, in 1996, the Kihansi spray toad and two rare plant species endemic to the Kihansi Gorge. The spray toad is only found within the natural spray area of that gorge. NORAD was immediately informed and decided to carry out a new environmental study of the endemic species, which is still underway. For unknown reasons, the Tanzanian parastatal that operates the dam was not informed about these developments until 1998.

Civil society groups inside Tanzania and internationally are now working to hold project donors responsible for the environmental problems in Kihansi. Friends of the Earth (FoE) US have written letters demanding donors react to the problems at Kihansi. In its response, the World Bank de–emphasized environmental problems, and claimed that the spray toad is not really in danger of being exterminated. It also mentions that water releases will increase in the future, but the proposal for such releases is far below the minimum required, according to experts.

FoE's letter to NORAD prompted a debate in Norway, both publicly and internally at NORAD. The main concern internally was reportedly how to save the endemic spray toad to avoid transgressing the International Convention on Biological Diversity.

The Norwegian NGO FIVAS has criticised the environmental planning at Kihansi from the beginning, and advised NORAD not to engage in the project. FIVAS also recently wrote NORAD, pointing out that the environmental problems in Kihansi are far bigger than the threatened species, and urging mitigation measures that address the full range of problems, not just those affecting the spray toad.

The author is a member of FIVAS (Association for International Water and Forest Studies). For more information: email:; Tel: +47–22 98 93 00; web: