P R E S S    R E L E A S E

Press release: 3rd World Water Forum, Kyoto, March 17

Striking the balance between water for food
and water for the environment

Pilot analysis shows human water use significantly
threatens freshwater ecosystems

A recent assessment of water needs suggests that unless at least 30 per cent of the world's river flow is allocated to maintaining freshwater ecosystems, we could see the collapse of many local economies and communities - over 1.4 billion people live in river basins where high water stress levels threaten the environment.

The message is simple: we are abstracting too much water from our rivers, streams, and lakes.

The 'global environmental water scarcity map' - a product of the joint study by the International Water Management Institute (IWMI), the World Resources Institute (WRI), the Center for Environmental Systems Research of Kassel University (KU) and IUCN, the World Conservation Union - demonstrates that a balanced water allocation policy is needed, one that provides sufficient water to the environment, as well as to agriculture, industry, and domestic use.

The study is the first to look at the requirements of freshwater ecosystems on a global scale. It also shows where water diversions impact on freshwater ecosystems downstream, and to what extent, as well as enabling researchers to look at the trade-offs between agriculture and the environment.

The Water, Food and Environment sessions of the Third World Water Forum have been chosen as a suitable opportunity to introduce this concept.

All over the world there are examples of basins where the over-exploitation of freshwater is threatening ecosystems. In both the Murray-Darling Basin in Australia and the Huang Ho River Basin in China more water is abstracted than is available for human use- a water stress indicator greater than 1 - while abstraction in the Orange River Basin in southern Africa is close to using the maximum amount available - a water stress indicator of 0.8 to 0.9.

In the case of the Huang Ho River Basin the duration of low-flow periods in the river increased from forty days in the early 1990s to two hundred days in 1997. This has placed enormous stress on more than 100 million people in the basin, undermining their capacity to grow crops, as well as taking a toll on freshwater species and habitats. The basin is an area in crisis - both for people and nature.

"Freshwater species and habitats are highly threatened, more so than any other ecosystems on earth. Without sustaining the underlying freshwater ecosystem and its dependent species, we will lose many of the goods and services we take for granted, such as clean water, fisheries and flood control," argues Carmen Revenga, Senior Associate at WRI. She adds: "Unfortunately the poor, who depend the most on these goods and services for their survival, tend to suffer the consequences of this lack of integrated management."

According to the 2003 IUCN Red List of Threatened Species, 3011 freshwater species are listed as threatened, endangered, or extinct - of which 1039 species are fish. For some countries and regions more detailed information is available. In South Africa, 63 percent of freshwater fish are threatened or endangered; in Europe, 42 percent; and in Iran, 22 percent. Globally it is estimated that 20 percent of 10, 000 fish species are threatened, endangered, or extinct.

The water scarcity assessment is intended to improve existing approaches, which at present, often compare water withdrawal to water availability, without considering environmental requirements. The assessment will help pin-point where aquatic ecosystems are threatened and what proportion of a basin's water needs to be allocated to ensure their survival.

"The quantification of eco-hydrological processes in most of the world remains poor at present" says Vladimir Smakhtin, Principal Researcher at IWMI. "In many developing countries, environmental water requirements have never been estimated. We need to fill this gap. The allocation of water for the environment should no longer be considered a waste"

The assessment works on the premise that since river flow regimes change worldwide, so will environmental water requirements. It is assumed, for example, that ecosystems in river basins with highly variable hydrological regimes may need a lower proportion of natural runoff to maintain their functions because aquatic life has adapted to the extended periods of limited or no flow. Estimates of environment water requirement in such basins will be dominated by a proportion of high flows in the wet season. This applies to monsoon driven river systems and rivers in arid areas.

The aquatic life in river basins where river flows are relatively steady, however, is more sensitive to water scarcity and will require a larger proportion of natural runoff. Estimates of environment water requirement for such basins will be dominated by a proportion of stable flows throughout the year. This applies to rivers in the equatorial belt or basins with a high proportion of lakes. Under current assumptions, the estimates of environmental water requirements range globally from 20 to 50 per cent of total water available per water basin.

Environmental water requirements could become an integral part of holistic approaches to freshwater management, building on the work of a number of international initiatives. The Comprehensive Assessment of Water Management in Agriculture - an initiative that takes stock of agricultural water use and its impacts in order to shape better investments in water for food and the environment - could use the requirement indicators to help provide communities with improved options for managing their freshwater resources, for instance.

"The global environmental flows map enables us to demonstrate to communities the trade-offs between water for agriculture and water for the environment," says David Molden, Principle Researcher at IWMI and Chair of the Comprehensive Assessment steering committee. He continues: "With this analysis we can get a better understanding of the levels of water we can tap to provide food security, without degrading aquatic ecosystems. This information then enables communities to make better quality decisions regarding the future allocation of water."

The IUCN Water and Nature Initiative - aimed at implementing sustainable water resources management - is specifically looking at methodologies to reserve water for environmental needs and implementing those in various river basins around the world.

"The Pangani River Basin, shared by Kenya and Tanzania, has seen its river flows drop from over 300 cubic meters per second to less than 40," says John Scanlon, Head of the IUCN Environmental Law Center. He adds: "The people there, and especially the poorest, see and feel the impacts on their environment, their ability to produce food and catch fish. IUCN is working with the government and communities on the methodology and negotiations to allocate water for ecosystem services."

The Dialogue on Water, Food and Environment - an initiative aiming to improve water resources management by bridging the gap between the food and environment sectors through open and transparent dialogues - could also benefit from this new assessment. Environmental requirement indicators could serve as the basis for negotiations among various users at basin-level, and help different groups reach agreements in which both irrigation and ecosystem functions are sustained.

"How much water is needed for the environment is a key question. It is one of the questions asked by and to stakeholders involved in dialogues on the ground. Estimating environmental flows is the first step in reaching a consensus among different users on how much water should be allocated for the maintenance of ecological integrity in any given basin," argues Domitille Vallee, acting co-ordinator of the Dialogue.

Concluding, Frank Rijsberman, Director General of IWMI, says: "Estimates of environmental water requirements should be incorporated into global assessments of water resources and use, and water and food security projections. As more water is withdrawn for human use, the pressure on freshwater ecosystems grows and the need to estimate and maintain ecosystem water requirements becomes progressively urgent. We need to pursue this research further."

For interviews or further information please contact Sanjini de Silva Dias, Communications Coordinator, International Water Management Institute.(s.desilva-dias@cgiar.org)