80 CONVENIENT SOLUTIONS TO AN INCONVENIENT TRUTH
factor limiting development in the Western Cape; where water is available, it is already fully used for agricultural, industrial, and domestic use. The spread of exotic trees in the mountain catchment areas surrounding Cape Town could reduce water resources for this rapidly growing city by another 30 percent. These losses could mean that more (and expensive) dams have to be built to meet the demand for water. Economic studies have shown that clearing invasive species in the catchment areas will increase water production and deliver water supplies at much less cost than building a new reservoir (see box 4.6 ). Additionally, invasive plants in indigenous grasslands and scrublands increase fuel loads and fire risk, which leads to increased soil erosion, degradation, and loss of biodiversity and ecosystem services in mountain catchments. The South African government has taken serious action to address these threats through the Working for Water and the Working for Fire programs, which are collaborating with the Bank–Global Environment Facility (GEF) CAPE Biodiversity Conservation and Sustainable Development Project to better manage and control invasive species in the Cape Floristic Region. Working for Water brings additional benefits through increased employment opportunities for disenfranchised groups. Support to Working for Water from the Bank’s Development Marketplace has increased employment opportunities for marginalized people through small-scale industries that use the harvested alien trees.
BOX 4.6
A Cost-Effective Solution for Increasing Water Supply: Removing Invasive Species in South Africa South Africa has a serious problem of invasive alien plants that affects 10 million hectares (8.28 percent) of the country. These invasions come at a significant ecological and economic cost. Invasive species, with their high evapotranspiration rates, are an immense burden to already water-scarce regions. Numerous studies have analyzed the role of invasive alien plants in decreasing the amount of water available to reservoirs. In 2002 the South African government approved R 1.4 billion ($173.5 million) for the proposed Skuifraam Dam Project on the Berg River near Franschhoek to help address the looming water crisis in the Western Cape and Cape Town. A feasibility study for the planned dam demonstrated that water delivery would cost 3 cents less per kiloliter if invasive species were managed in the catchment area. It was estimated that clearing invasive plants from the Theewaterskloof catchment would deliver additional water at only 10.5 percent of the cost of delivery from the new Skuifraam scheme if no clearance was carried out. Accordingly, large-scale programs to clear invasive trees are being undertaken as part of management for the new Berg Dam. Source: Pierce and others 2002.