Plans to eradicate alien weeds infesting Southern Africa’s rivers have been ”indefinitely” derailed by administrative delays, a World Bank official confirmed on Wednesday.
A multimillion-dollar anti-infestation project was due to start last year, but has been delayed by the relocating of the Southern African Development Community’s (SADC) water section to Gaborone in Botswana.
The initial phases targeted three trans-boundary pilot sites:
- The Caledon/Orange river basin in Lesotho and South Africa;
- Kwando/Linyanthi/Chobe system in Namibia and Botswana; and
- The Lower Shire in Malawi and Mozambique.
”Among the administrative questions raised were technical capacity and procurement issues,” said Aziz Bouzaher, an environment specialist at the World Bank in Johannesburg.
”The World Bank was involved in the preparatory phase, but since July 2003 there were some issues raised and lots had to be done to complete the preparatory requirements for the phase,” Bouzaher said.
However, he emphasised the bank is still committed to the project, but ”the ball was in the court of [the] SADC”.
Rhodes University’s Prof Martin Hill, chairperson of the International Organisation for Biological Control working group dealing with water hyacinth, said aquatic weeds are a severe problem in Africa.
”Water hyacinth is the worst of these weeds and has invaded many of the lakes and river systems in Africa with devastating consequences. The severity of the problem threatens the development of Africa, none more so than on Lake Victoria,” he said.
At its worst, this lake was infested by more than 20 000ha of the weed, now down to 2 000ha because of biocontrol measures. The weed float about in huge mats and infest inlets and fishing beaches.
Hill said it is estimated that 80% of the Ugandan shoreline is infested with a permanent 10m fringe of the weed, causing the shorelines to become impenetrable when ”colonised” with other aquatic plants.
”The dominant socio-economic activities around Lake Victoria and its catchment, which include agriculture, hydroelectic power generation, fisheries, lake transport and water supply for both domestic and industrial use, have been heavily impacted by water hyacinth,” he said.
Trade in and out of ports of countries surrounding the lake — Kenya, Uganda and Tanzania — has also been seriously affected.
The economic and environmental impact of these weeds is practically impossible to estimate. A New Partnership for Africa’s Development (Nepad) environmental document suggested it cost seven unnamed African countries about $50-million per year just to manage the water hyacinth.
The five main invasive aquatic weeds in Africa are water hyacinth, water lettuce, salvinia, parrot’s feather and red water fern, all originally from South America.
Hill said these alien water weeds thrive in Africa’s waterways because of nutrient-rich waters and a lack of natural enemies.
Besides reducing the quality and quantity of water for urban, agricultural and industrial uses, the dense mats of weeds cause an increase in siltation of rivers, dams and wetlands.
The weeds also reduce water surface areas for recreation, clog irrigation canals and pumps, and cause livestock drownings and severe deterioration of aquatic biodiversity.
Hill said biological control is the most sustainable management tool, with significant success already achieved throughout the continent.
”However, the long-term management of alien aquatic vegetation relies on the prevention of other species entering Africa and … the reduction of nutrients entering aquatic ecosystems.”
Hill said the delayed SADC initiative is one of several initiatives undertaken to deal with alien aquatic weeds. An ”African clearinghouse” has also been proposed to disseminate information and help provide a better-coordinated response among experts and policy-makers.
He said even though some projects have not yet officially been implemented, things are still happening at a ”non-official” level.
”Things are happening without a formal structure, and perhaps that is good because we are not hamstrung with all the bureaucracy,” said Hill, who nevertheless stressed the need for a formalised response to the alien weed problem. — Sapa