Water is essential to the processes of society. Water resource management must not only try to ensure sufficient quantities of water but also acceptable water quality and accessibility. Water management authorities may be overwhelmed and/or mismanage water resources and services. These stem from rapid population growth and the dramatic increase in per capita water consumption as a result of modern development. About 1,000 million people still lack an adequate water supply, and about 1,700 million people do not have adequate sanitation facilities. The quality of the service as well as the water can often be poor. These are problems particularly plaguing developing countries. Agricultural irrigation, in particular, may be mismanaged. It accounts for about 73% of all water withdrawals, but roughly half of this amount is not used by crops. One reason for such inefficiencies is that agricultural water is also significantly cheaper for the user than other water applications are to their users. Such practices need to be reduced by improving water resource management, and in order to ensure sustainable water resource use.
When a recent drought dangerously reduced available water, California set up a voluntary water bank that purchased water from farmers and sold it to urban areas. The farmers made a profit by selling water for more than it was worth to them, while the cities got water at a cost well below that of other sources of supply. In the 1960s the government of the USA concluded that sixteen dams and more than US$ 400 million were required to meet the water needs of Washington DC. Environmental pressure forced plans to be reconsidered. The number of dams was reduced to one at a total cost of US$ 30 million. The key changes were a revised plan for managing demand during droughts and more efficient operating rules. Also in the USA, manufacturing industry freshwater withdrawals are estimated to be 62% less in 2000 than in 1977, primarily because of the increased costs industries have to pay for disposing of industrial wastewater.
The city of Jakarta, Indonesia, has had success in reducing overpumping of its aquifers by registering groundwater users and introducing a groundwater levy. In Sao Paolo, Brazil, three industrial plants reduced their water demand by between 42 and 62% as a result of the imposition of effluent charges.
UNESCO's programme includes the following: evaluating the impacts of global and regional climate changes on water resources; improving scientific understanding of water-related issues and sustainable water resource management in the humid tropics; strengthening member states' capabilities in the preparation of water-resource master plans.
This strategy features in the framework of Agenda 21 as formulated at UNCED (Rio de Janeiro, 1992), now coordinated by the United Nations Commission on Sustainable Development and implemented through national and local authorities. Agenda 21 recommends protecting the quality and supply of freshwater resources through application of integrated approaches to the development, management and use of water resources.