The Root of the Solution - The Role of Plants in Stormwater Management

Stormwater is managed for quality and quantity, and plants play a major role in improving both. It’s no secret that plants provide ecological benefits, but sometimes we forget how crucial they can be in an effective stormwater management strategy.

When we employ engineered stormwater strategies, we try to mimic some of the benefits plants provide to a watershed when precipitation occurs. Picture the difference in water quality of runoff from a forested tract of land versus a recently plowed farm field. Neither of these land uses contains impervious features such as houses, parking lots, or sidewalks. However, the difference in runoff quality and quantity is striking, and a powerful example of what plants provide in an ecosystem.

In the past, stormwater management strategies attempted to mitigate the effects of plant removal by storing and slowly releasing stormwater from a developed site (think detention pond). Although that type of stormwater best management practice (BMP) can provide some benefits, the beneficial utilization of plants is unfortunately missing. Today, there are many ways site developers can incorporate the power of plants into an overall stormwater management strategy.

The strategic placement of trees, shrubs, and other plantings can help slow down and capture some of the precipitation adjacent to impervious areas of the site as it falls to the ground, eventually returning the water into the atmosphere through evapotranspiration. The placement of vegetated swales can help direct the flow and infiltration of stormwater along portions of the site while also providing an opportunity for nutrient and sediment uptake. Rain gardens or bioretention BMPs can replace traditional open detention or infiltration basins, providing similar but much improved water quality function. Beyond all of that, plants provide for an aesthetically pleasing landscape and provide much-needed habitat for a whole array of wildlife.