Inspired by the Netherlands, Montreal is adopting water squares to mitigate urban flooding.
By Katharine Logan
Montreal?s Place des Fleurs-de-Macadam is part of the city?s investment in
Dutch-style water squares. Photo by Roxanne Marcil.
?The main achievement is to provide a high-quality public space in a dense area of the city where there are not many parks or green spaces,? says Mélanie Mignault, a landscape architect with NIPPAYSAGE. ?Then, on top of that, to protect neighborhood residents from [flooding].?
When it rains, the paved central area acts as an enormous basin with up to a foot of retention depth. At the center of the basin, a regulated drain releases water slowly to the sunken beds, completely emptying in no more than 48 hours. (If the system reaches capacity, an overflow drain leads to the municipal sewer.) The beds, which are bumped out to occupy the parking lanes of two adjacent streets, also have inlets for road runoff, and their soil substrate is designed to support both deep and shallow root networks that will help improve infiltration capacity over time. When tested, Place des Fleurs-de-Macadam proved capable of absorbing more than 97 percent of a 100-year storm, with each dollar invested predicted to save at least five in averted flood damage. ?People go there just to see the rainwater pond,? Bérard says, ?which is incredible, because rainwater used to be this thing that we wanted to get rid of the fastest way possible.?
Katharine Logan is an award-w...