Adapting Stormwater Design Standards to Meet Future Community Needs
Today’s stormwater design standards are basic and simplistic, focusing solely on rerouting stormwater runoff away from built environments. But this strategy may be passing the risk of flooding downstream in addition to creating more significant and costly problems for downstream communities.
Adopting stormwater design standards that are adaptive and viewing stormwater as a resource rather than waste not only stops passing the problem downstream, but also offers more progressive and resilient solutions that provide greater community benefits.
Traditionally, stormwater design has focused on the lowest common denominator, where the goal is moving excess rainfall away from the built environment — buildings, roads, streets or parking lots — as quickly as possible. Stormwater systems are typically sized to handle large and more extreme rainfall events.
Conversely, these systems lack adaptability to slow down smaller, more common events, passing all of the excess rainfall downstream almost immediately. This causes problems downstream that may include undermined road crossings, property damage, flash flooding and eroding streams. Communities at the bottom of the watersheds then pay the price for our current practices, requiring solutions that are more expensive and complex.
We need to rethink stormwater design standards to create practices that stop passing the buck downstream, and that instead view stormwater as a resource, adding more adaptability to urban environments.
Smarter stormwater design standards provide a more resilient solution for urban environments by capturing excess rainfall closer to the source, slowing it down, allowing a portion of it to infiltrate the ground where it falls and reducing the amount that is sent to sewer systems. Reusing water from frequent runoff events to sustain vegetation in green spaces or storing roof runoff in a rain barrel to irrigate an urban garden are more sustainable solutions.
One way to do this is through green stormwater infrastructure strategies that adapt to Mother Nature. These strategies can have a powerful and positive impact on communities. The Smart Sewer Program in Kansas City, Missouri, demonstrates how this can work.
Another way to develop more adaptive stormwater solutions is to create systems with smart controls, ones that can open or close a valve based on the weather forecast and water levels. These solutions provide a higher value to a community because they manage a full range of rainfall events, from the small frequent events to the large extreme events.
It’s time to move away from passive stormwater systems and embrace smarter, more adaptive systems that better meet our needs for today and tomorrow. This requires that existing stormwater standards be updated to incorporate more sophisticated designs that consider a range of possible rainfall events and not just one extreme event. These standards support a systems approach and consider downstream impacts. They support adaptive solutions that can change in the future along with land use and climate.
Communities across the country can benefit from this more adaptive approach that uses existing natural resources in more productive ways with less damage to the environment and downstream communities.