As spring washes winter away with blossoming flowers and lush foliage an all too common hazard returns to our lives. Flooding impacts more and more people every year – a trend that is having substantial impacts on both urban and rural areas across the country. Flooding adversely impacts quality of life, property value and public safety. Believe it or not, the answer to these problems may be all around us in natural undisturbed areas.
If you’ve ever been caught in a woodland or prairie during a rainstorm you might have noticed a quizzical lack of sewer inlets. That’s because nature has been in the stormwater management business long before the first city came to pass. Utilizing soil porosity instead of sewer pipe, and beaver dams in place of detention basins, natural areas tend to reach a level of near equilibrium that may be the key to building resilient cities that provide not only for public safety but also a higher quality of life.
Urbanization has the potential to significantly increase both the frequency and intensity of flooding (up to 600 percent according to the USGS). Examples of this can be seen all across the country with increasing frequency each spring as the rains come. Traditional development patterns have reduced time of concentration and increased runoff quantities through the use of impermeable surfaces and rapid conveyance. These archaic strategies put more water into streams that have been channelized more rapidly than ever experienced in recent history. As cities become larger and more developed, these effects increase exponentially as watersheds become more urbanized.
Thanks to innovative concepts like biomimicry, we have a blueprint to “peel back the pavement” and uncap our cities. Healthy soils and native plants slow runoff resulting in longer concentration times and lower runoff intensities. This increase in time of concentration results in more infiltration, less erosion, lower turbidity, higher transpiration rates, lower nutrient loss, and more locally available water for plants and animals. This collectively reduces the amount of water flowing into rivers and streams during heavy storm events, and reduces the frequency and intensity of flood events. Stormwater Best Management Practices (BMPs) that mimic natural systems can be applied at all scales of development from city wide infrastructure systems to backyard pollinator gardens. The U.S. Environmental Protection Agency is a great place to start learning more about Green Infrastructure and how you can help build a resilient city for the future.