HOW THE WORLD MANAGES IT'S WATER RESOURCES

usa : The state of Arizona is moving towards a unique groundwater banking system. Entities that recharge groundwater receive credit for the amount recharged, which they can then sell to groundwater users. The Groundwater Management Act ( gma ) has established a goal of zero groundwater mining by the year 2025. Groundwater users are penalised for withdrawing the precious resource without recharging it. These penalties force the user to either recharge groundwater or purchase it from a supplier.

"Groundwater recharge has to be an integral part of water resource planning in urban areas because the traditional means require exploitation of surface and sub-surface resources to the maximum extent possible,' says Peter Fox of Arizona State University and an ardent advocate of aquifer recharge.

mexico : At Monterrey in Mexico, ground and surface water sources fail to meet the demands of industries. To maintain adequate water supplies, industries, individually or as a consortium, have constructed wastewater treatment plants.

Wastewater purchased from the city is sent to a treatment plant where it is treated and distributed to industries. While individual industry owners reuse the treated water in their own plants, in places where there is a consortium, it is distributed through a network.

With the construction of three large wastewater treatment plants by the Monterrey Water and Wastewater Authority in the city, virtually all wastewater is treated and reused either directly, for non-potable use, or indirectly for potable water use throughout the city.

germany : "In Germany, rainwater harvesting is recognised as an advanced, ecologically and permanently safe operating system,' says Klaus Konig from Professional Association for Water Recycling and Rainwater Catchment Systems, a ngo from Uberlingen, Germany.

In the nineties, several thousand installations using rainwater were put up. The quality of rainwater collected is governed by regulations, which also protect the potable water system from possible contamination by individual installations.

Under the Berlin Communal Dwelling Rainwater Utilisation Project, water from rooftops is disposed through the public rainwater sewers of the Berlin Water Companies. This water along with the outflow from streets, parking spaces and pathways, is transferred into cisterns. After simple treatment, this water is used for toilet and gardening.

Hectic efforts are on to develop an efficient ceramic toilet that uses only 3 litres for flushing. All rooms in the Arabella Hotel in Berlin are equipped with a water-saving toilet system, which has a split operation panel. For flushing faeces, 4 litres are used, while for flushing urine it is only 2.5 litres.

However, proponents of rainwater harvesting are facing opposition from another front. Many arrangements for the supply of water exist but the demand is low. The projected demand for the year 2000 was based on a study undertaken in 1975 and this turned out to be a gross overestimation.

singapore : In Singapore, the Public Utilities Board ( pub ) provides reliable potable water at economical rates. Water literacy programmes, people's participation and reliable water meters that are regularly monitored, coupled with a responsive group of public engineers, ensure the success of the project.

Plumbers are given licenses to ensure quality. The pub inspects all sanitary fittings and pipes before installation. All accounts are metered, even temporary ones. These meters are checked on a monthly basis and a computer detects fluctuations. If three readings are high, customers are advised to check for leaks. They are also encouraged to take their own readings.

israel : Israel survives with less than 300 cubic metres of water per capita per year. International organisations define countries, with less than 1,000 cubic metres per capita per year, as highly stressed. "The answer lies in water demand management,' reveals S Arlosoroff, an expert in water management.