Design, Gardening, Water Management

Innovative Water Strategies Part 3 – Green Roofs and Bioswales

“Though the problems of the world are increasingly complex, the solutions remain embarrassingly simple.” – Bill Mollison

I’m happy to be writing this post on a rainy Friday in Vancouver! It was actually nice to pull out my umbrella after many months of dust collection in the closet. But I imagine it’s not enough to pull us out of this ‘drought’ status, so therefore we continue onward with the sustainable water management! Looks like it’s going to be longer than my original 3-part plan…

Green Roofs

Unlike the many ‘green’ products today, in this case we’re talking literally green: rather than asphalt shingles or metal roofs, one can cover their abode with flora and fauna. This might be a tough sell in a building code-ridden city, but if you can pull it off it has serious benefits:Water perspires and cools the building

  • Plants filter and clean water before collection
  • Filters air pollutants and dust in vicinity
  • Reduces water runoff to drains
  • Looks super cool!

Keep in mind however the massive structural load you’ll incur when you pile a few truckloads of dirt and plants on the top of your building, plus the added pounds when it rains.

The green roof at the Vancouver Convention Centre

Bio Swales

Chances are you’ve seen these in your travels and not thought much of it, but there is a lot of conscious design that goes in to creating a functioning bioswale. In its most simple form, a bioswale collects surface runoff water from any higher location (a hill, parking lot, road, or building roof) and runs it through a course of vegetation or natural material like compost. It is very effective at cleaning pollutants from the water and allowing time for it to soak back into the ground before draining to sewer.

Now if you’re ever driving and see a concrete culvert collecting water on the side of the road, you can now think to yourself, ‘Hey! There’s a way better way to do that!”

Bioswale in a parking lot at the University of California, Santa Barbara
Bioswale in a parking lot at the University of California, Santa Barbara

Innovative Road Design

The standard method for building a road is to give it a crowned shape (highest point in the middle) and in North America, building them big and wide. This collects considerable water, which typically flows outwards until it hits a curb, until finally completing its short journey to the sewer. This is great news for kids racing toothpicks in the gutter, but not so great for taking care of our water supply.

The solution here is to add bioswales either in the middle of the road as a divider or on the outsides, and to simply construct narrower roads wherever possible. Think European!


7414375The next part in our series will be a case study of one of my favorite buildings in Vancouver. Stay tuned!

(Thanks again to Hans Schreier at the UBC for the topics and pictures)

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