The Commission blames overuse and misuse of land and water resources in river basins in both industrialised countries and developing countries for the decline. River depletion and pollution have also helped create 25 million environmental refugees in 1999, the Commission says. North American freshwater species face a five times higher risk of extinction than land animals as a consequence of river basin mismanagement.
Many rivers are being depleted because global demand for water is rising sharply. The problem will be further aggravated by having to meet the needs for food, drinking water and water for economic development of the additional 2 billion people on the planet by 2025.
Among the most stressed rivers are:
- China’s Yellow River ran dry in its lower reaches 226 days out of the year in 1997. The North China Plain is home to around 400 million people and is a major food producing region for the whole country. The region is watered by the Yellow River and two others. In order to meet irrigation needs, farmers are drawing up large amounts of water from aquifers. All three rivers are heavily polluted as a result of rapid industrialisation. The Chinese Government has spent $3 billion over the past four years on a conservation programme, the main focus of which has been on the introduction of drip irrigation systems on farms
- The Amu Darya’s and Syr Darya’s flow into the Aral Sea has been reduced by three quarters. As a result, sea levels dropped 16m between 1962 and 1994. Agricultural pollution has contributed to infant mortality in the region and disease
- The Colorado River in the US is used by agriculture to irrigate more than 1.5 million ha of farmland. This has led to the destruction of downstream ecosystems and the prevention of groundwater recharge
- More than 90 percent of the Nile is used by agriculture or is lost through evaporation from reservoirs. The flow that reaches the Mediterranean is heavily polluted
- Up to 97 percent of the surface water in the Volga River Basin is considered unsafe as a source of drinking water
- Only a third of the Jordan’s natural flow now reaches the Dead Sea
- Only two of the world’s major rivers can be classified as healthy: the Amazon – which has few settlements or industrial centres on its bank – and the Congo, for similar reasons.
The Commission says improvements depend on changes to land use in river basins, but warns that many rivers may never return to their original state. The Commission acknowledges that water quality has improved in the northern hemisphere, but says toxic substances are still circulating in fish and shellfish and that fertilisers remain a major cause of pollution.
There are several individual signs of improvement, however. The St Lawrence River, the Rhine, Australia’s Murray-Darling River Basin and Mexico’s Lerma River have all recovered dramatically over the last 30 years as a result of concerted restoration efforts by governments, businesses, farmers and consumer groups.
Nonetheless, rivers in developing countries continue to suffer as the result of increased demand causing decreased flows and inadequate pollution prevention measures.
The Commission warns that the accelerating depletion of useable water resources poses a major challenge for world food security. The world’s population derives 40 percent of its food from irrigated lands.
The construction of dams, dikes and levees, river diversions for irrigation and the draining of wetlands also contribute to decreased flows. Decreased flows and increased pollution result in downstream ecosystem degradation.
Globally, less than 10 percent of total waste is treated before it enters rivers.
The Commission says that integrated land and water resources policy reforms for entire river basins, regardless of regional or national borders, is the best method to improve river water quality. This must include a recognition of the cost of water and of water services. “If people pay the full cost of water services provided to them, they will waste less and financing will be available for both water supply and cleanup,” says William Cosgrove, Director of the Commission’s Vision Unit.
“We must adopt a comprehensive framework to address political, economic, social and environmental dimensions of resource management issues,” says Ismail Serageldin, Chairman of the Commission. “We must address energy, public health, water sanitation and environment quality within a single framework. Land and water degradation issues would no longer be seen as an environmental issue, but rather as very central to the sustainable development agenda of a country. The world has to significantly increase water productivity while restoring the world’s damaged rivers, if we are to have any hope of meeting the water needs of the 8 billlion people, while protecting the environment.”