WATER EFFICIENT CITIES OF THE FUTURE

Cities of the future will have to be more prepared for the danger of flooding, while at the same time be more efficient in the use of drinking water. The world as a whole is in dire need of sustainable water management, according to SWITCH, a joint project of the European Union and 32 partner organisations. "At this moment over one billion people do not enjoy a service of drinking water. More two and a half billion people have no access to sanitation facilities."

A Dutch professor is the Scientific Director of SWITCH, an acronym for Sustainable Water management Improves Tomorrow's Cities' Health. SWITCH searches for new ways to improve water efficiency, to protect cities against floods and to make clear to governments that a new water management policy is necessary to prepare cities for the future.

‘It's time for a change in the way we use water in our cities’, warns the professor. But, he says, ‘old habits die hard. Here in the West, for instance, we've grown so accustomed to having clear drinking water aplenty that we use it for very inferior purposes. At the extreme end of the scale I'd like to point at the flush toilet where we use drinking water, crystal clear with the only purpose to transport excreta out of the city. And what happens when this wastewater gets into the environment? 85 percent of all wastewater produced worldwide is at this moment contaminating our water resources. That leads to pollution but it also leads to very serious health treats.’

In the future, problems will only get worse because of the growth of mega-cities such as Beijing, Shanghai or Mexico City where more than 10 million people live huddled together.
‘Those mega-cities create an enormous disruption in the countryside and the water balance. In a city everything is paved with tarmac and when it rains the water can't go anywhere, and so flooding occurs. That's why it's important to re-establish the natural situation. We have to become more conscious of space in a city: create open spaces that can retain rain water and that can function at the same time as recreation area - or nature area.’

In the Netherlands sustainable use of water is obligatory by law. The latest findings and solutions are tried out in new housing development projects. In the centre of the Netherlands, for instance, an ingenious system of ditches, canals and wadis (a retention area for rain water) is used to save the new neighbourhoods from flooding after heavy rainfall, explains a spokesman of a Dutch engineering company. ‘The neighbourhood is set up in such a way that it seeks balance. The wadi, at first sight a low lying patch of grass in the neighbourhood, combines a nice bit of greenery with water management. Previously, all rain water used to go straight into the sewage system. Now the water runs through drains to the grass plot. When it rains heavily the wadi is completely flooded. The water then gradually seeps into the soil and the advantage is that the sewage system can be a lot smaller.’

The professor sees more technical solutions ahead. Vacuum toilets, like the ones used in airplanes, do not use any water and should be adapted, he says, for the home situation. Even in mega-cities, where space is very limited he sees possibilities for the implementation of 'green zones'. He's convinced it's not too late to turn the tide. ‘Infrastructure has a life-time of 20 to 40, 50 years and we see regularly, also in Europe, that whole areas in cities are reconstructed - those are the opportunities to start doing things differently and make cities again pleasant to live in and in balance with their environment.’

Also river beds are reconstructed now.  Farmers cooperate with the authorities to put their farms on mounds and take away the dykes along the river. If there will be too much water, the cattle will be moved on the mounds, while the open land gets temporarily flooded. In this way enough water can be stored to safeguard the large cities in the west of the country. more features

September 8 , 2006