Building Resilient Cities

Many cities and communities across the world have encountered elevated heat and fluctuating precipitation levels in recent years. ASTM International’s climate and community subcommittee (E50.07), part of the committee on environmental assessment, risk management and corrective action (E50), has developed standards to help communities adapt to the changing climate. These standards include guides for stormwater infrastructure, heat-absorbing ponds, and urban green spaces. I spoke with Paul Sonnenfeld, vice chair of the subcommittee, about how these standards are being used today and how future standards may help with climate-related challenges in the future.

The standard guide for climate resiliency planning and strategy (E3032) concerns resilience strategies that cities and communities can adopt. What are some examples of those strategies in practice?

There are many climate adaptation and resilience strategies that cities and communities can now take. The city of Portland is a leader in green stormwater infrastructure, specifically green streets that blend the stormwater system into the streets to capture runoff before it reaches drains. The city also installs vegetated medians between the sidewalks in the road verge. This allows rain and precipitation to infiltrate the soil before entering the stormwater system, reducing its burden and providing groundwater recharge. The Port of Seattle has installed many rain gardens at its facilities so that stormwater falling on impervious surfaces flows to areas with soil and vegetation. The stormwater infiltrates the soil, and contaminants are trapped and captured by the plants. Washington state revised its entire construction stormwater manual so that new construction sites integrate a range of stormwater management structures. These structures keep construction runoff on site, trapping sediments and contaminants, filtering the water, and allowing it to return to groundwater. Examples of this include detention basins, infiltration ponds, grass-lined channels, preservation of native vegetation, and bioswales.

We also see cities doing much more to address potential flooding from rivers and streams — fluvial flooding — in addition to what I already discussed about flooding associated with heavy rainfall. For example, Dubuque, Iowa redesigned its downtown stormwater system so that stormwater is captured and used to irrigate parks, while adjacent structures are protected. In western Washington, there is a strong emphasis on managing rainfall in a way that protects property, prevents flooding, and diverts swollen rivers to open spaces owned by municipal agencies or to agricultural land where owners have agreed to allow river overflows to irrigate their property, providing needed rainfall and irrigation while preventing damage elsewhere.

How does the proposed standard on nature-based solutions for urban heat (WK95551) fit into that effort? 

The nature‑based solutions for urban heat are specifically designed for neighborhoods and communities because the standard will provide users with tools and techniques to identify areas where nature‑based solutions can be most effectively implemented to reduce the urban heat load. We’re looking at commonly available and effective nature‑based solutions, including green canopies, water resources — such as ponds and pools that absorb heat instead of radiating it back from buildings — and changing building colors. For example, the Asphalt Roofing Manufacturers Association is heavily involved in this standard, and a simple change like switching roofing tiles from black or gray to a lighter color — tan, pale yellow, or beige — significantly increases albedo, which means the roof reflects heat rather than becoming a heat source. We’re also exploring green walls. The National Research Council of Canada (NRC) has been a leading authority in this area, and representatives from the NRC are heavily involved in this effort. Faculty members from Yale, Duke, Washington State University, and Kansas State University are also participating in developing the standard. There are many climate adaptation and resilience strategies that cities and communities can now take.

What’s another key standard that contributes to the resilience effort, and how does it do so? 

The standard guide for use of activity and use limitations, including institutional and engineering controls (E2091) is extremely important for federal landholding agencies such as the Department of the Interior, the Department of Energy, and the Department of Agriculture, which have long‑term stewardship requirements for contaminated sites. In cases where the federal government will manage remediation for decades, resiliency and planning for climate and extreme weather are crucial, because we must ensure that any institutional or engineering controls imposed on the property are long‑term and resilient. For example, if we use an engineering control or physical barrier, such as a concrete or asphalt cap, to prevent contact with contaminated soil at an environmentally impaired site, we need to know its lifespan and how well it handles temperature extremes. If we employ a pump‑and‑treat system for contaminated groundwater, we must consider whether we have reliable long‑term power contracts and whether the site is suitable for solar, wind, or other green-energy sources. These types of lifecycle analyses allow the federal landholding agency to determine if additional remediation now is more prudent than the costs associated with long-term operations and maintenance.

What are some areas of need for which you could see standards being developed in the coming years?

 I live in the U.S. Pacific Northwest, and over the last 30 years, I have observed and documented changes in rainfall frequency and intensity. Washington state is in its fourth year of declared droughts. Our neighboring states, such as Idaho and Oregon and other portions of the western U.S., are also experiencing droughts and hotter summers. Those droughts mean less water in the streams and rivers, which translates into higher water temperatures that adversely affect the fish that swim in those waters and shellfish, such as crabs, in our bays and estuaries. These warmer water temperatures wreak havoc on fisheries. See, for example, the devastation to the Alaska snow crab fishery due to warmer water in the Bering Sea.

The warmer summers and winters also mean that insect infestations, such as the mountain pine beetle, rapidly expand in the forests of the western U.S. and Canada. In the event of lightning-induced fires, the weakened trees add to the fuel load that leads to catastrophic forest fires, such as the 2024 fire in Jasper, Alberta.

All those factors weigh on my perspective to support the development of climate-related standards. The standards developed by ASTM provide tools, techniques, and mechanisms so our children’s generation and their children’s generation have the means to quickly adapt and maintain resiliency for future generations.