The first question you may have is, what is a bioswale? There’s a long and short answer. I’m going to give you the answer in between those two. A bioswale is a way to manage rainwater and other precipitation (aka stormwater) in a more ecological and environmentally sensitive way.
When rain falls on a surface like a parking lot nearly all of it (around 98%) will “runoff” into a storm drain. If you compare that with a lawn, far less will runoff a grassy area. Also, when rain flows across a parking lot, it picks up all of the grime, oil and dirt on the surface of parking lot…and parking lots, roads and highways are particularly filthy. After that, all of the rainwater (that is now full of all of the mess that was on the parking lot) goes into a storm drain and is then directed to the nearest river, creek, estuary or stream.
Detention is a good thing. When it rains, all of the rainwater starts running into storm drains at the same time…and thereby is outflowing into the local river all at the same time. It’s this sudden and amplified presence of water in a river that actually causes water to break dams and overpower flood protections downstream. If we had more bioswales holding more water as well as cleaning it, we would have much healthier aquatic ecosystems as well as more effective control of stormwater. This control would give us cleaner beaches and rivers and greatly reduce flooding in many places.
Other Reasons for Excitement
So, the opportunity to design a bioswale is exciting because they are eco-heroes, and who doesn’t want more eco-heroes in their life? The other reasons for excitement is that this project can turn a fairly nondescript part of a downtown into a centerpiece that helps make it a more desirable place to go. This is usually referred to as placemaking, that is, designing and making places that people love and feel enriched when they go to them. I’ve always felt that placemaking should also use design to express a sense of self-value as well as a value for the people that use them. Or said differently, I think places need to be visually stunning as well as extremely usable and practical.
Back to the Bioswale
So the vision for the bioswale is to be an ecological wonder, a spectacular spot to visit and a great addition to the downtown area. That’s a big order for a narrow strip of dirt, but the preliminary design is moving in that direction. Below is a sneak peek at the current design. When you compare it to the existing conditions, it’s a huge improvement. Right now, the strip is planted with a few evergreen shrubs that are not overly interesting or ecologically beneficial. Our design will use native perennials and grasses in the bioswale. If everything goes well this week, we will start to select specific plants for the bioswale next week.
The average onlooker will likely never see the true power of this bioswale, because it will be underground. We are proposing to use a series of stormwater cells to detain as much water as possible. A single cell can hold just under 32 gallons of stormwater.
I’m even proposing we repaint the parking spots so that the bioswale can get more attention. All together, I hope we get to complete the design and can get it installed this year. As more updates come, I’ll try to write blogs about them.