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Private companies have a role to play in helping cities overcome water challenges, says Tao Bindslev, Grundfos Group Vice President. Photograph: Grundfos

Around the world cities are creating dramatic water savings with water metres, pressure management, groundwater conservation and more. But is it enough?

From fixing leaks in Johannesburg, to topping up groundwater in Salisbury, to flushing toilets with seawater in Hong Kong, municipalities around the world are working to save water and make their distribution systems more efficient.

The need for action to secure future water supplies is clear enough.

“The issue of water is paramount, and the pressure on cities is increasing,” says Seth Schultz, director of research of the C40 Cities Climate Leadership Group, a global network of cities taking action to reduce carbon emissions and climate risks.

Among other things, he cites a recent C40 survey of major cities around the world in which 65% of these municipalities are expecting “substantive risks” to their water supplies. These risks include water scarcity, declining water quality, flooding and an inadequate or ageing water infrastructure.

Copenhagen cuts water consumption in half

One city that has successfully met the challenge of diminishing water supplies is Copenhagen. The Danish capital managed to reduce its yearly water consumption from 100m m3 in the late 1970s to 55m today. Water metering is one of many strategies that helped the city to reach this achievement.

“Without individual water metres, a consumer has no incentive to save. But after we installed metres, we could see over a period of years that consumption was reduced by an average of 15%,” says planning manager Jens Andersen of the Greater Copenhagen Utility Company.

Reducing leak losses

Like many other water-wise cities, Copenhagen also worked to reduce leaks. Studies from the 2030 Water Resources Group show that 50% or more of the water that is pumped into a distribution grid can be lost before it ever reaches the consumer.

Water-saving campaigns, rising water prices and a growing awareness of the need for conservation have also helped reduce consumption.

“Our leakage losses are now down to just 7%,” says Jens Andersen. “Thanks to some highly advanced listening equipment, we’ve become better at finding the holes in our pipes. We’re also better at renewal planning, so we can prioritise the oldest and most heavily used areas of the grid.”

‘Smart’ technologies take off the pressure

In the 2030 Water Resources Group case studies, many cities – including Cape Town, Johannesburg and Jeddah – also found that if they simply reduce water pressure in the grid, they also reduce leakage and minimise wear and tear on ageing pipes.

To this end, smart technologies such as the Demand Driven Distribution pressure control system developed by Grundfos can save both water and money by delivering optimal water pressure at any given time, says group vice president Tao Bindslev, who heads up the company’s water utility business.

“This system can automatically monitor grid use patterns with remote sensors and adjust the water pressure accordingly,” he says. “This reduces both water and electricity consumption by up to 20%, and water pipes will last longer because they are less likely to crack.”

The return on investment, says Tao Bindslev, is “very short. In some cases down to a year.”

Private companies with specialised knowledge such as Grundfos have a role to play in helping cities overcome their water supply challenges, says Tao Bindslev.

“Grundfos is working with city designers and consultants at every point in the water cycle on creating sustainable urban designs for water management systems,” he says.

Still no ‘distant oasis’

But not all responses to water conservation projects have been positive. A study by the US environmental group Nature Conservancy is sceptical of expensive water projects. It contends that cities need to rethink the practice of establishing new water sources in faraway rivers and reservoirs. Ultimately, there is no “distant oasis” that can solve a city’s water problems.

Instead, the study points to conservation as the most sustainable and cost-effective way to address water shortages. One of the most effective ideas of all, the authors argue, involves local farms.

Massive amounts of water could be freed up for urban use if cities compensate farmers for establishing more efficient irrigation technologies such as lined canals and improved delivery systems. The farmers would also benefit from the subsidy, and experience increased productivity.

Cities are ready and able to change

Despite the challenges, Seth Schultz is convinced that cities are both willing and able to make the changes that are necessary for a sustainable, water-scarce future.

“The good news is that city mayors actually have very strong powers in the water sector, as such cities have the ability to make changes in this area,” he says. “So yes, I’m very optimistic. But I also know how much more needs to happen.”

SOURCE: Guardian http://www.theguardian.com/sustainable-business/grundfos-partner-zone/2014/nov/05/smart-cities-secure-water-supplies-while-global-risks-loom