Water Sustainability & How to Achieve It

By Chris Hill

Three elements of a sustainable water future.

Three elements of a sustainable water future.

What is water sustainability?

Great cities are defined and illuminated by the water that surrounds or flows through them. From the harbors of New York to the river estuaries of London to Amsterdam’s canals or the beaches of Sydney, water is what gives a city its unique magnetism.

Top cities understand and address their water in a sustainable manner. This means efficiently providing safe, reliable, and easily accessible water as well as reliable sanitation and waterways protected from pollution. Sustainability also means being resilient and adaptable to extreme weather events that may contribute to issues such as flooding and scarcity.

The Arcadis Sustainable Cities Water Index assessed 50 global cities by the stewardship of their water across issues impacting their water resiliency, efficiency and quality to show which cities are best positioned to harness water for their long-term success.

Each of the 50 cities included in the index have distinctive water relationships that helped shape their urban character and define their commercial identity and competitiveness. The study highlights the importance of water as an urban asset critical to long-term success, economic development and overall sustainability. North American cities, threatened by both water scarcity and natural disasters, are among the most at risk in the developed world. As a result, no U.S. cities placed in the top 10 of the global rankings of water sustainability. Still, there’s a lot to be learned from successes in the United States.

The Challenges of Achieving Water Sustainability

Now more than ever, cities, their waterscapes and water sources face challenges: water demand is rising, aquifers are being depleted and the threat of extreme weather is increasing. Aging infrastructure and funding issues continue to plague systems worldwide. On the other hand, increased use of automation and technology — key tools to achieve efficiency — are themselves vulnerable to disruption.

Cities are responsible for protecting their citizens from pollutants, diseases and destructive storm surges that can be difficult to anticipate. Urbanization causes further demand for drinking water and sanitation, while increasing impermeable areas that can contribute to flooding. As a result, many cities are struggling and many more are vulnerable.

The overall index examines the water sustainability of 50 cities from 31 countries across all continents.

The overall index examines the water sustainability of 50 cities from 31 countries across all continents. Cities are ranked according to not only how sustainably they manage and maintain water, but also against their natural risk and vulnerability across three pillars of water sustainability — resiliency, efficiency and quality.

How to Create a Sustainable Water Future for Cities

There is no single winning strategy to achieve urban water sustainability. Natural and manmade challenges call for different interventions from city to city.

There are many things that can be done to improve water sustainability. Let us take a look at some strategies and best practices that can make our cities fit for the future by making them a better and safer place to live, visit and conduct business.

Policy and Planning

Resiliency as a Pathway Towards Sustainability

Major cities worldwide have now placed resiliency planning on the agenda, an initial step to becoming more sustainable. The scope of resiliency is not just about structures and protection but also is about disaster recovery. Resiliency extends to the ‘soft’ infrastructure of society, including employment, income distribution, social cohesion and other factors not usually built into water management.

Urban adaptive planning

With the abundance of challenges our urban world is now facing, it is difficult to exactly plan and design for the mid- and long-term future. It is precisely for this reason that modern planning practices have to be adaptive and risk-based, as well as flexible enough to account for unexpected circumstances or developments.

A good example of adaptive planning is San Francisco, which responded to the city’s natural vulnerability to sea level rise by conducting a comprehensive assessment of two of the lowest-lying parts of the city: Mission Creek and Mission Bay. The city used ‘inundation maps’ to assess the vulnerability of important infrastructure to sea level rise and to identify potential weak points and how to address them. Using these insights, this former industrial area of port facilities and rail yards can be redeveloped for residential and commercial use.

Resilience

Green Space and Multi-Purpose Urban Solutions

Many cities are turning to green infrastructure projects to manage stormwater issues as an alternative to traditional methods of piped drainage. Green infrastructure can provide valuable green space and recreation for the residents of a city, reduce the urban heat island effect, and enhance biodiversity and ecological resilience.

The South Los Angeles Wetlands Park was designed to capture and treat urban runoff, while providing rare green space to an underserved community of Los Angeles. The project transformed a previously abandoned railyard, which was a brownfield site, into a park with trails, boardwalks, picnic areas and other features.

Stormwater Management

When it rains, the water that runs off our roofs can be collected, where allowable, for future reuse with minimum hassle. Rainwater harvesting is increasingly practiced in larger urban facilities including sports arenas and recreational complexes. In many cities it is worthwhile to collect this water instead of letting it drain into the subsoil or directly in collection systems. This approach is gaining popularity in many water scarce areas.

For example, Singapore is currently committing to infrastructure that is designed to capture every drop of rain that falls. Los Angeles is capturing stormwater and using it to recharge drinking water aquifers and the city of Melbourne is piloting a project to capture rainwater from roofs and store it in tanks to be used for toilet flushing and lawn watering.

Desalination

Desalination can be a reliable source of drinking water that enables continuity and access for a city’s inhabitants. Taking saltwater from the ocean and turning it into usable freshwater is commonplace in many arid coastal locations. It is, in fact, the fastest growing alternative water supply source in the world and can be a valuable weapon for cities looking to diversify their water supply and reduce water shortages.

Water Reuse

Effectively reusing and transporting water in a cost-effective and safe way can contribute considerably to water availability and can be crucial to meeting a city’s long-term demand. More and more often, the water we drink starts out as natural water that has been used before.

Increasingly cities are treating their own wastewater for reuse, such as agricultural, industrial, source water replenishment, and increasingly for potable water. The level of treatment required is dependent on the end use and the end uses vary depending on the particular conditions and needs of the city.

Water reuse is very common in California. The West Basin Water Utility in greater Los Angeles has taken reuse a step further and introduced its ‘designer water’ program, providing up to five different types of water for various commercial, industrial and irrigation uses. This also includes groundwater injection to create a barrier to salt water intrusion into its groundwater supply. The idea behind this is to treat only certain quantities to specific treatment levels that are needed to sustain demand at any given time. In essence, they are treating water to order.

Efficiency

Optimization of Urban Water Use

Optimization of water resources starts with a good knowledge of assets, system performance and the types and levels of usage, both current and projected. Combining this information with knowledge of the system’s vulnerabilities, risks and stress points lead to actionable plans that can help utilities produce greater efficiencies. Further, showing how these vulnerabilities can threaten city operations, quality of life or even the city’s competitive edge will provide important insights for planning.

Urban Asset Preservation and Management

Aging urban water infrastructure poses a serious challenge. Deferred maintenance and spending have resulted in a major funding gap. Risk-based asset management approaches are increasingly being used to prioritize capital and operating investments. This means allocating funds to address specific risks and those assets with the highest potential of failure.  This also focuses resources against assets whose failure would have the biggest impact on the urban economy, environment and communities.

The Tarrant Regional Water District outside of Dallas has the overall goal of achieving 100 percent reliability and energy optimization to transmit raw water. As such, they have embarked on a project that comprises the development of a formal asset management program and the development of a real-time energy consumption optimization decision support tool.

Water Quality

Water quality is arguably where urban sustainability performance is highest, since drinking water plays such a critical role in quality of life. Cities in the developed world have historically improved their prosperity and economies only after adequately addressing water quality and sanitation. Cities in the developing world, however, will need to improve water quality to become prosperous, sustainable urban centers.

Chicago ranks very high in quality because of the historic decision to reverse the flow of the Chicago River to protect the quality of Lake Michigan. The city’s tunnel and reservoir program (TARP) manages critical infrastructure to prevent combined sewer overflows to Lake Michigan. As a result, Chicago has a very clean and reliable source of drinking water for its residents.

Water Sustainability on the Urban Agenda

As we’ve seen, water sustainability impacts the quality of life of cities in far-reaching ways. With so much at stake, utilities and city leadership will be central in shaping the future of their urban environment. Developing the investment needed to achieve these long-range goals will be critical to success. Fortunately, the case can now be made that water sustainability and resilience produce ROI in the form of both economic and societal benefits.


Hill

Christopher Hill, P.E., BCEE, ENV SP, is a vice president of Arcadis, the Water Supply & Treatment Lead for North America, and a board member of the Water Environment & Reuse Foundation. He has 24 years of experience as a drinking water expert, applying innovative vision and proven technical expertise to more than 100 projects for cities and communities around the world. Hill has a keen understanding of the water cycle, which includes wastewater treatment and resource recovery, and is recognized as a thought leader in alternative water supply solutions such as reuse and desalination.

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