In the downtown core of BC’s capital city, I’m glad there are some spots where pedestrians enjoy some separation from the vehicle traffic as they all go about their busy schedules.
But in this spot, on the northeast corner of Yates & Blanshard streets, it’s more than just a pretty boulevard. Here nature is working hard as a public utility: a rain garden.
A rain garden is basically a ditch.
Most cities have been done with ditches for ages, favouring underground storm drain systems to pipe rainwater away quickly. Although that sounds pretty civilized, it means:
- water drains so fast that there’s no time for it to soak in and nourish boulevard trees & landscaping, much less refill the natural water table
- street pollution washes into the storm system and then dumps directly into streams or the ocean
- in heavy rains, the storm drain system can’t handle the rush of runoff, so streets flood anyway
The rain garden acts as a bit of a pond containing the flow for a small rain event (about 2.5 cm rainfall). That’s the amount that washes the oils & chemicals off the street.
The trees, plants, and soils in the ditch are not only nourished, but they also break down the pollutants before the water infiltrates more deeply into the earth beneath.
It sounds kinda crazy that plants can break down pollution, doesn’t it? Science swears it’s true.
In a heavier rainstorm, the runoff gathers in the rain garden, and the excess water flows more slowly away in that handy storm drain system.
It sounds like a win-win situation to me.
The rain irrigates the garden naturally.
Pollutants are treated by an effective process.
There’s less flooding now & the storm drain system won’t need expensive pipe enlargements to handle the increased rains we’re getting over the past few years.
I especially appreciate that the gardens provide some natural beauty to an otherwise glass, steel & concrete desert.
Now the curiosity rises in my mind: which trees & plants thrive in one of these ditches? They’d need to be happy with both very wet feet in winter and very dry in summer…. ideas?
© copyright 2012 SVSeekins
P.S. Check here for more on rain gardens: