Bioretention as a winning focus for local ecosystem protection.

The Puget Sound area hasn’t always been this way. There were no highways 300 years ago. There were more trees. There were fewer people, fewer rooftops, and fewer hard surfaces for the rain to splash against as it meandered its way down to the saltwater.

As the population has increased, contaminants have also increased. Fertilizer from lawns meets up with grease from cars and restaurants in our storm drains. Meanwhile, stormwater managers do their best to deal with the increased runoff resulting from more and more hardened surfaces.

Scientists have studied these issues for several decades, considering various stormwater management techniques. We can’t turn back the clock, converting all that concrete and compacted soil back to loamy fields and forest floors. But we’ve discovered that there are things we can do, inspired by our area’s native landscape, to create meaningful and positive impacts. Through a method known as bioretention, residents of the Puget Sound region (human and otherwise) can realize a host of benefits, including less strain on stormwater systems, reduced flooding, reduced contaminants, reduced toxicity to salmon, more habitat and shade, and urban beautification.

Bioretention is one way of mimicking the premodern natural management of rainfall and runoff. Rather than having large, centralized facilities like detention ponds, bioretention is decentralized—treating and infiltrating stormwater close to where the rain lands. Bioretention uses plants, microbes, and soils to reduce the harmful effects of stormwater runoff. Not only does this keep toxic compounds out of Puget Sound, but it also reduces stress on municipal stormwater systems.

As you might imagine, bioretention facilities work best when they are well designed and properly maintained. But to our delight, we’ve found that even undersized or atypical designs for bioretention are very effective. These facilities do more to control and treat runoff than we anticipated.

We’ve discovered that there are things we can do, inspired by our area’s native landscape, to create meaningful and positive impacts.

So, what can you do? Washington’s city leaders can increase bioretention in many ways. Cities and towns can identify municipally owned properties that are well suited for bioretention, and they can encourage private developers to think about stormwater management at the beginning of the design process to make the most use of bioretention. Cities can also encourage businesses and residents to install new bioretention features and to maintain existing ones. For example, Bellingham provides financial incentives for bioretention that meets specific requirements.

Expanding bioretention won’t return the Puget Sound region to a pristine, premodern past. But it can mitigate and reduce some of the harmful effects of urban life on our rivers, streams, and receiving waters. City leaders should consider encouraging bioretention, either directly or indirectly, in new projects and in redevelopments, restorations, and retrofits.

Brandi Lubliner is a stormwater engineer and managing coordinator of the Stormwater Action Monitoring program with the Washington Department of Ecology.