The passing of the 2021 Federal Infrastructure Bill remains a monumental advancement towards updating water systems in cities across America. Despite this, most U.S. cities continue to reference decades-old federal precipitation records that fail to account for climate change. This oversight has left cities ill-equipped to handle increasing precipitation levels, damaging infrastructure while endangering the lives of residents.
When designing stormwater structures, civil engineers establish criteria for infrastructure capacity using several tools, including a design storm; a hypothetical rainfall event based on long-term precipitation data. To determine a design storm, engineers often use NOAA’s Atlas 14 Reports which provide precipitation intensity, duration, and frequency estimates. Currently, many states are using outdated reports and data to inform the capacity of stormwater systems, which may result in storm drain pipes that cannot convey stormwater runoff from increasing rainfall depths. Even if using updated rainfall data, stormwater infrastructure may still fail or perform worse than expected, because NOAA’s Atlas 14 Reports are a reflection of past rainfall events instead of accounting for future events that are predicted to be more intense.
To improve the resiliency of stormwater infrastructure, some states have partnered with local universities and researchers to develop localized climate change projections. Most notably, Portland and Seattle have teamed up with the University of Washington’s Climate Impact Group to develop tools to visualize projected changes in extreme precipitation. When working with clients across the Pacific Northwest, Herrera often utilizes climate change projections to design infrastructure and develop coordinated resiliency and adaptation strategies that economically reduce risks and help protect infrastructure, utilities, operations, critical supply lines, and public health and safety.
Though the utilization of climate projection data remains an emerging practice, funding from the infrastructure bill is a promising start to ensure all stormwater systems are prepared to handle the effects of climate change.