Trends in urban water infrastructure design
Urban planners use water infrastructure design to reap a host of benefits, including flood control, water quality improvements and ecological habitat protection. SWS Managing Editor Amy McIntosh asked S. Bry Sarté, founding partner of Sherwood Design Engineers and author of the book, "Innovations in Water Infrastructure," about how engineers are using this multipurpose infrastructure in urban environments.
Amy McIntosh: How has urban water infrastructure design evolved in recent years?
S. Bry Sarté: One of the biggest changes is the shift in perspective on storm water from a nuisance to a valuable resource. Sherwood [Engineers] became heavily involved with innovative, onsite storm water treatment, capture and reuse techniques about 15 years ago. Since then, we’ve moved from building-scale infrastructure to district-scale systems, and our design process has broadened into a resource optimization approach.
Today, many cities have permitting and incentive structures in place to promote advanced water management systems. ... A great example is Hudson Yards in Manhattan, N.Y., the largest private development in U.S. history. We designed a net-zero water system for the 6-acre park and streetscape that will capture and reuse about 6 million gal of storm water a year. So Hudson Yards' landscape won’t draw from drinking water sources. We also looked even more broadly at the connection between water and the other infrastructure systems on the site. At Hudson Yards, which is a concrete platform suspended over an active railroad yard, the storm water storage system will also cool the platform to protect plants from waste heat generated from below.
McIntosh: What are some emerging trends in urban water infrastructure design?
Sarté: Today we look at water infrastructure as an opportunity to drive site design to achieve benefits beyond flood protection and improved drought management. Water infrastructure can improve aesthetics and user experience of an urban area, provide parks and open space, and reduce (or eliminate) the contribution of site runoff to overburdened water infrastructure. Other important changes in recent years include new financing structures, such as the ability to monetize wastewater load reductions, and our growing ability to engage regulators to secure entitlements for innovative solutions that require broader thinking about the scope of problems and solutions.
McIntosh: How can water infrastructure design benefit the health of an urban community?
Sarté: Keeping sewage out of rivers and streams is the most direct benefit. We can improve human and ecological health with smarter water infrastructure. Advanced onsite water management systems can also drastically reduce the burden on urban sewer systems. For example, the 6 million gal of storm water a year that will be captured, treated and reused at Hudson Yards won’t contribute to New York City’s combined sewer overflow problems. Another example is how these systems can reduce the urban heat island effect by providing shade [and] evapotranspiration from vegetation, and increasing reflective surfaces.
McIntosh: What social benefits emerge from the use of urban water infrastructure?
Sarté: Maybe the biggest potential benefits out there from advancing water infrastructure design are related to energy. Extracting, treating and distributing water uses an enormous amount of energy. On the other side of the equation, generating power consumes an enormous amount of water. The California Energy Commission estimates that 20% of the state’s electricity is consumed on water-related energy use. Onsite water infrastructure that captures, treats and reuses storm water can play a big role in breaking this negative water/energy feedback loop.