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This technology is based upon the recognition that rarely is water shortage a question of inadequate precipitation, but a problem of limited infiltration and storage space.

There are three major components to the Swedish technology: the collection area, the conveyance system and the storage facility. The collection area can cover the entire landscape, by taking advantage of the natural topography. The conveyance system is natural: the forces of gravity ensure that water enters the geological structure surrounding the cavern only to find its way to the lowest point in the hydraulic system. This gravity system can be improved by drilling holes between the cavern and neighbouring fissures. Storage depends on the size of the cavern, which is a large porous fissure that becomes part of the geological structure.

The technology is fairly cheap and initial investments range from Rs. 2000 to Rs. 4000 ($50 - $100) per cubic metre of created cavern. Thus water that would be otherwise lost to flash floods and evaporation can be safely collected and stored underground.

‘Groundwater recharge has to be an integral part of water resource planning in urban areas now, given the fact that traditional means to meet growing water demand in urban areas requires the exploitation of surface and subsurface resources to the maximun extent possible, adds Fox.

The most common way of aquifer recharge is the use of recharge basins where water is allowed to collect on large pieces of land that allow the stored water to percolate through. This however is land intensive. Technologies are now available where the water can be recharged into an aquifer by injecting into wells that are dug above an aquifer and the water percolates into it or through a direct injection well that ends in an aquifer.

Arizona is moving towards a groundwater banking system. Entities that recharge groundwater receive credit for the amount of groundwater they are recharging, which they can then sell to groundwater users. The Groundwater Management Act (GMA) has established a goal of zero groundwater mining by the Year2025. The GMA has established a system of ground water management systems combined with a system of penalties and incentives. Groundwater users are penalised on an escalating scale for withdrawing groundwater without recharging it. The penalties force the groundwater user to either recharge groundwater or purchase groundwater from a ground water supplier.

Wastewater is purchased from the city, pumped from the sewer into a treatment plant and the treated water distributed to industries. While individual industry owners reuse the treated water on their own plant property, in places where there is a consortium, the treated water is distributed through a water distribution network.

With the construction of 3 large wastewater treatment plants in the city by the Monterrey Water and Wastewater Authority, virtually all the wastewater from the city is treated and reused either directly for non potable use or indirectly for potable water use throughout the city.

Germany: Germany appears to have realised the potential of harvesting rainwater. "Rainwater utilisation is now 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 Germany, in the nineties, several thousand rainwater utilisation installations have been installed. To ensure the quality of rainwater collected and that the potable water system is protected and secure from possible contamination by individual installations, there now exist legally binding regulations within the German potable legislation. For instance, no connection may be made between the rainwater system and the potable water system.

Singapore: In Singapore, the Public Utilities Board (PUB) is the national water authority. It has proven to be an efficient organisation providing reliable potable water at the most ecoomical cost. Programmes of water literacy, people’s participation and reliable water meters that are regularly monitored coupled with a responsive group of public engineers has been the formula adopted. Plumbers are given licenses to ensure good quality of plumbing work. All water fittings and pipes are inspected by the PUB before installation. All accounts are metered, even temporary ones at worksites. These metres are checked monthly. The billing is computerised and any fluctuations are automatically detected by the computer. Customers are advised to check for leaks if the readings are abnormally high. They are also encouraged to take their own readings. Replacement of mains have reduced leakage problems and improved water quality.

Israel: The million dollar question is: how does Israel survive with less than 300 cubic metres of water per capita per year when international organisations define arid countries with less than 1000 cubic metres per capita per year as highly stressed countries where water becomes a severe constraint to growth.

Source: All inputs below are based on the 3 day symposium on ‘Efficient Water Use in Urban Areas- innovative ways of finding water in cities,’ held in Japan between 8-10 June, 1999. The symposium was organised by United Nations Environment Programme - International Environmental Technology Centre, Kobe, Japan