City water supplies – innovating solutions to meet the rising demand

As cities swell in size, supplying clean water poses a challenge. In 1900, to prevent pollution of the drinking waters in Lake Michigan, engineers reversed the flow of the Chicago River. Today, innovators seek sustainable water solutions in new technology, untapped sources, and good infrastructure.

Urban centers face the added challenge of having to supply more water from shrinking and inaccessible sources. From Dubai to Qingdao, cities are now finding new methods of water management. With new technologies and out-of-the-box thinking, sources of water are springing up, which cities are drawing on with unquenchable success.

Ensuring the future is green – Environmental sustainable development draws on concepts of little waste, lower consumption and switching to green, environmentally-sustainable resources like solar and wind or materials which can constantly be up-cycled.

Published on 21.06.2016

33 countries likely to face high water stress by 2040
33 countries likely to face high water stress by 2040 – ©WRI

Desalination to top up depleted water sources

Many coastal regions are working with desalination. Qingdao, a seaside city in China, constructed a desalination plant which can produce water for 500,000 residents every day. It uses reverse osmosis to filter ocean water, stripping it of salt and impurities. Desalination plants, however, can be expensive to run and waste energy. Also, if care is not taken, they can harm marine life. But there are ways to balance out the potential side-effects of desalination plants.

Diversify to multiply. More sources boost sustainability.

Singapore gets potable water from desalination plants but also through importation, rainwater and recycling wastewater. Diversifying sources and optimizing technology creates a sustainable infrastructure which benefits the environment.
The United Arab Emirates’ desalination plant in Jebel Ali created better technology that increases not only potable water supplies but also the capacity for electricity production, thus reducing the country’s carbon footprint.

The Chandreja Reservoir, in Spain, also supplies fresh water to cities and contributes to meeting the goal of creating 40 percent of the country’s energy needs from renewable sources by 2020.

A beautiful sight, the Chandreja Reservoir in Spain
A beautiful sight, the Chandreja Reservoir in Spain

Recycling wastewater to drinking water

That’s right, wastewater. Wastewater undergoes a four-step reverse osmosis process removing all contaminants and toxins. It presents the added challenge of educating residents that with purification technology there are no dangers, but the extra work has proven to be worthwhile.

Singapore is not the only city to turn to this until now untapped source. In Windhoek, Namibia, 26 percent of the city’s water supply comes from wastewater. And, in Arua, Uganda, there is a proposal for a low-tech system of decentralized wastewater treatment systems (DEWATS) and soil aquifer treatment (SAT) to bring clean water to the city outskirts.

Brazil’s water levels rise and fall with the effects of climate change

Maintaining clear waters through thick and thin

Efficient water management relies on a city supporting an infrastructure which combines innovative thinking in water conservation and water storage. Many cities have access to water, but variability is high.

São Paulo draws on six reservoirs, linked by 48 km of tunnels to store freshwater. Yet, recently, the system has been under strain due to drought, and could benefit from a policy similar to Singapore’s which seeks to meet demands from a mix of sources, like recycling water.

Or it could take inspiration from Los Angeles. To combat evaporation and conserve water levels, 96 million shade balls were released into the Los Angeles Reservoir.

Good water management can mean juggling a lot of balls – Los Angeles puts them all to good use in water conservation

'Shade Balls:'  What Are They and How Are They Saving Water?

“Urban water infrastructure in the future will look quite different compared to now. It will consider water scarcity and quality, as well as energy use and generation in an entirely different way.”

Julia Bucknall

Sector Manager, Water Unit at the World Bank

Going to the next level of water management

Out-of-box thinking will provide the key to many future ideas, but good green policies – like reducing forestation to combat climate-change and enforcing low water consumption – will contribute to creating an overall sustainable solution.

Building on the experiences cities like Singapore and Los Angeles have started, others are moving to implementing an integrated urban water management (IUWM). A holistic approach to water management, IUWM seeks a more diverse set of options for dealing with the complex challenges cities face.

The future of water management – as well as water levels – is looking up.