Coping with the growing water demand of cities is one of the most pressing challenges of this century - half of the world’s population now lives in cities and the figure is rising.
But help is at hand from nature if we stop taking for granted the ‘free’ services that ecosystems such as forests, river basins and wetlands provide.
Around a third of the world’s biggest cities obtain a large amount of their drinking water from protected areas including national parks and forest reserves. Protected grassland and forest watersheds where no logging, agriculture or mining are allowed are the best guardians of water quality and some forest types can also improve water flow. This service is all the more critical with climate change causing unpredictable rainfall patterns in many parts of the world.
Mount Kenya catchment © Sue Stolton
Cape Town, South Africa extracts significant water from the extensive mountain catchment and wilderness areas that now form the Cape Floral Kingdom Protected Areas World Heritage Site. Through the highly innovative Working for Water Programme, management to address alien invasive species and fire risk contributes greatly to water quality and quantity in metropolitan Cape Town, while creating employment and conserving biodiversity.
Nairobi, the capital of Kenya, has a population of 3 million, which according to the United Nations Human Settlement Programme is increasing at 5% per cent per year. The city draws its water from several sources including the Ruiru, Sasumua, Chania II and Ndakaini catchments.
As the population grows, the country’s per capita water supply is predicted to fall significantly. The main rivers flowing from the Aberdares mountain range which includes the Aberdares National Park, and the Mount Kenya water catchment area supply Nairobi with drinking water but much of the area is being logged which may make the city’s water supply even more unreliable.
Better recognition by policy makers of the benefits provided by protected areas that conserve watersheds could help to pay for their management but the economic value of watersheds is still under-estimated. Several market-based approaches and payments schemes are being tried and these will be showcased at the IUCN World Parks Congress 2014 taking place in November in Sydney, Australia. The event will present the latest research on the benefits protected areas provide to society and encourage both government and the private sector to invest in them.