Professor Ignacio Rodrigues-Iturbe of Princeton University, USA, won the 2002 Stockholm Water Prize.Click here to enlarge imageUnfortunately, water has become - maybe the main - victim of economic growth due to widespread wilful neglect. Waste production is intimately linked to wealth-generating processes but it degrades water for other users dependent on the same river system.
Water accessible for use in rivers and aquifers originates from precipitation over drainage basins. The non-evaporated part of the precipitation continually recharges rivers and aquifers; however the non-evaporated fraction is dependent on land cover and land use, especially in tropical regions with high evaporative demand of the atmosphere. In such regions, river runoff is vulnerable to deforestation, reforestation, fires and other land cover changes.
Water is withdrawn from rivers and aquifers for many different purposes. After being used, it returns to the water cycle in two ways:
- after irrigation, the consumptive use evaporates and leaves the basin not available for reuse downstream, while the surplus part goes as a return flow to the land where it finds its way back to a local river or aquifer;
- after throughflow-based uses in cities and industries, water returns loaded with pollutants that degrade water quality and complicate downstream reuse.
Geographic locations of water stakeholders in the basin determine the upstream and downstream pattern of water withdrawals, consumptive uses and return flows. As long as water demands are low relative to water availability, allocation of water does not involve much competition. Pollution loads added to the river by industries, however, create serious water quality problems. Consequently, problems may exacerbate quickly when water demands grow. An effective water resources management strategy must include ways to successfully orchestrate the chain of consecutive users so that all relevant uses can be properly met.
Compromise-building mechanisms must be developed to balance competing needs for usable water resources. The challenge originates from two fundamental problems -
- the consumptive uses which deplete the river flow, reducing downstream availability as can be seen in rivers located in many developing countries today;
- and pollution loads, which reduce downstream usability and may even cause considerable human suffering as witnessed in the Aral Sea region.
Water demands may start to compete within a country as population continues to grow, more food production is needed, and industrial development proceeds. This situation calls for the development of criteria for priorities. Governments must establish compromise-building mechanisms and stakeholder participation must be built into the decision-making process to ensure that decisions are socially acceptable. These criteria must include adequate attention to the water needed to support riparian wetlands and aquatic ecosystems. An "uncommitted environmental flow" must remain through ecologically important river stretches.
Currently, many global regions have already reached a water withdrawal level in which most river flow is already committed and the rivers are "closing" in the sense that no water remains for consumption. This means that compro-mise-building processes must be looked into closely and stakeholder participation must be properly organised and given legal status.
Author's note
Professor Malin Falkenmark is the senior scientist of the Stockholm International Water Institute, based in Stockholm, Sweden. She is also the Chair of the Scientific Program Committee for the Stockholm Water Symposium.
Stockholm Symposium to address 21st Century challenges
The 12th 2002 Stockholm Water Symposium will address problems related to the issue of balancing competing water uses. Special attention will be given to criteria for priorities between competing interests in a catchment; stakeholder participation in decision-making - institutional forms; water as a catalyst for development; industrial water pollution abatement; poverty alleviation with fundamental water implications; urban dynamics and the need to integrate water and energy.
