Protect forests, get clean water
what do cities like Mumbai, Karachi, Sao Paulo and Johannesburg have in common besides their high population? A strong reliance on forests for their drinking water, reveals Running Pure, a study by the World Bank and the World Wide Fund for Nature.
Around a third of the world's top 105 cities (by population) obtain a significant amount of their drinking water from the catchment areas of fully or partly protected forests. But they are not necessarily aware of this important role of forests. For instance, the economic value of 'water storage function' of China's forests is calculated to be three times more than the cost of their wood. If forests are to be maintained, their additional benefits (especially as a water resource) should be emphasised besides biodiversity conservation needs. "Protecting forests around water catchment areas is no longer a luxury but a necessity," asserts David Cassells, a senior environmental specialist for forest resources at the World Bank.
Presence of forests also means that the land is not available for agricultural and industrial activities, which generally cause groundwater pollution. Furthermore, well-managed natural forests regulate soil erosion, thus reducing sediment load. As a result, forests provide higher quality water with less sediment and fewer pollutants, compared to other catchment areas. The study cites the example of Melbourne, 90 per cent of whose water supply comes from well-managed mountainous catchments. Despite seven years of drought, the city's residents get the highest quality drinking water in the entire nation. According to the study, it is much cheaper to protect forests than to build water treatment plants. In 1997, after the us Environmental Protection Agency instigated that all surface water supplies to the cities should be filtered, New York had two options: protect its forests catchment area or construct another filtration plant. A cost analysis showed that protection of watershed area required us $1-1.5 billion over 10 years. This was a lot cheaper than constructing the filtration plant at the cost of us $6-8 billion.
The study suggests collecting fees from people and companies utilising drinking water to pay for managing the protected area. For example, in Costa Rica, hydropower companies pay farmers to maintain forest cover in watersheds. In Quito, Ecuador, water companies contribute towards the management of protected areas, which are a main source of the capital's water.
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