De-paving Ottawa; and Permeable pavements

De-paving is a trending catchword in the urban vocabulary. It describes removing already-paved areas and replacing them with porous surfaces.

A number of years ago, St Anthony schoolyard on Booth Street won a prize as worst schoolyard in Canada. For winning, they got to dig up a lot of the asphalt and replace it with trees and shrubs and well-composted woodchips. It still looks great. [conventional playstructures are falling rapidly out of favour due to expense, lack of interest and lack of challenge for schoolkids, and are being replaced by … naturalized wood lots].

It’s always curious that school boards have lots of money for paved parking lots, kept well maintained, but money suddenly becomes scarce for school yards. You’d almost think that schools were designed for teachers who commute by car rather than the kiddies incarcerated therein.

Some other schoolyards are following the St Anthony example, with one on Catherine being next in line for depaving.

For years I walked past the Juliana apartment building at the corner of Bronson and Albert Streets. One of the quiet joys of living in a capital city is the exotic-ness of what goes on here. The apartment building was home to the Embassy of the Royal Hashemite Kingdom. Hmm.

The front yard of the building has a nice garden. The southernmost bit of frontage, however, was a paved parking lot. Back in the 1980’s, this area was lawn. Then the building owners asked the city for permission to pave it, for “guest parking”. Shortly after it was paved [and any inspectors went on their way] the guest parking signs disappeared and reserved parking signs replaced them. The building operators thus could rent out the city boulevard for hundreds of dollars per month. Neat.

Now, decades later, we may be past peak-car, and the paved area has actually been replaced with lawn again.


Shortly after that, no dog poop signs appeared, which will have the secondary effect of blocking parking or snow dumping on the lawn:



I hope de-paving becomes more popular.

Closely related to depaving is permeable paving.

Earlier this fall, I noticed these Ecology Ottawa posters in the Glebe:



In neighbourhoods like mine, where the sewers are inadequate to carry off all the rain water (the Glebe fills up our main storm sewer to capacity before it even starts to go through Little Italy) I was part of the PAC for the “infrastructure renewal”. I suggested that rather than increase capacity in a futile attempt to catch up with paving, why not ban more asphalt paving * in the Glebe/Little Italy catchment area, and encourage rain water to permeate the soil. The city was ,,, distinctly … unenthused.

For example, when I built my side yard patio a few years back, replacing an unused driveway, I used pavers with wide-ish gaps between them (lugs on the sides of stones keep them evenly spaced apart) and set them in special stone dust that won’t compact, and remains water porous. Even in those torrential August downpours, water just runs straight down through the pavers rather than running off to overload the sewers. In comparison, ordinary pavers and regular stonedust aren’t really very porous. Most water runs off, just like asphalt.



I planted Irish moss between a few of my stones, and it has spread nicely since then giving the manufactured stones a softer look.

There is such a thing as porous concrete, usable for sidewalks, but the City isn’t interested in it because the pores that give it permeability might clog with winter sand and grit, and the sidewalks should be pressure washed yearly. Couldn’t have that, now could we?

Next: drainage swales on streets, with hundreds of exciting pictures !


* banning asphalt paving prevents the removal of existing permeable and semi-permeable areas. Over a decade, enormous areas of residential neighbourhoods are covered in paving. New developments, however, are regulated and required to hold 100% of their rainfall on site, and slowly release it over 24 hours. Thus new developments and intensification does not surcharge the sewers or cause flooding, but instead reduces the demand on our sewers.


A reader, GD, sent me these two links on permeable concrete:

This film / commercial is informative, and a number of other you-tube stories on the subject will also come up on your screen:;


One thought on “De-paving Ottawa; and Permeable pavements

  1. We’ve got regular pavers (150 mm) on our driveway and I don’t see large amounts of run-off from it, especially compared to neighbours’ asphalt driveways where water is clearly sheeting off it to the street. Those small gaps are surprisingly porous, in contrast to your claim that they’re just like asphalt. Mind you, we don’t have stonedust under them but rather sand and below that, granular B.

Comments are closed.