Rain Gardens–Part 1

Rain Gardens–Part 1

I’ve been reading up on Rain Gardens–timely, in view of the amount of rain we’ve had here in coastal BC the last two days!

A Rain Garden is a planted area designed to collect and gradually discharge storm water back into the ground. The areas from which storm water is collected include roofs, asphalt (driveways, roads, parking lots), sidewalks, even patios. Thanks to Rain Garden Network, here’s a graphic of what happens to rain water:

Small rural town with little development; runoff is doubled.

rain water 4 — Highly developed city; 55% of rainwater is runoff!

The problem with stormwater runoff is both where all that water goes, and what goes with it. Instead of recharging ground water and aquifers, the stormwater goes into the storm sewers, carrying with it road pollutants, lawn and garden chemicals (not YOURS of course!), various compounds from roofs and gutters. From there it goes into local streams, including fish bearing streams, rivers, lakes and ocean. Meanwhile, the ground is getting drier and drier.

Integrated Stormwater Management Plans (ISMP) are becoming big business these days. If you google your own city, you’ll no doubt find it has a stormwater management plan that goes well beyond building new sewers.

Back to Rain Gardens.

This is where garden design kicks in. There’s tons of information out there on how to design and build your own ISMP. All it takes is a little level-ish space (there are calculations to determine optimum size), a slightly concave depression (read “dig down 6-12”), a conduit to direct water from the impervious surface, and plants to make the garden beautiful.

Here’s a few images randomly selected to give you an idea:

A Portland Oregon Middle School award-winning rain garden.

The Rain Garden Retrofit. This pond in the centre of the garden will seep into the ground in a few hours--or a few hours after the rain stops falling! — The Rain Garden Retrofit. This pond in the centre of the garden will seep into the ground in a few hours–or a few hours after the rain stops falling!

There’s no end of creativity in developing your own rain garden. If you can’t build one in your own home, maybe your kids’ school is an appropriate place. Or the boulevard in front of your townhouse complex. Or the “low maintenance” border around your apartment building.

Stay tuned for Part 2 when I’ll get into the details of “How To…”.

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