Urban stormwater management

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What we face

Urban areas don’t soak up a lot of water. When fields and forests are replaced with roads, parking lots and buildings, less rainfall can seep into the ground, and more water collects on hard surfaces. Gravity then moves the runoff from those paved surfaces towards catch basins and into storm sewers.

What we do

Older areas

In neighbourhoods built prior to the 1980s, stormwater runoff does not typically receive any treatment. Contaminated with a lot of dirt and debris, stormwater runoff flows directly from the storm sewer into streams and rivers. There is little space in older urban areas to install large-scale stormwater facilities, like ponds, and parks can only compensate for so much.

The City has started exploring retrofit solutions to minimize the negative impact of uncontrolled runoff in Ottawa’s densely populated areas. Permeable parking lots, green streets, bioswales and rain gardens are only a few examples of stormwater infrastructure that can capture and filter runoff. The Pinecrest Creek/Westboro Stormwater Management Retrofit Plan contains a combination of measures to be implemented over the next 50 years in the Pinecrest/Westboro area.

Two engineered rain garden sites have already been constructed within the road right-of-way in Ottawa, one on Sunnyside Avenue in Old Ottawa South and one on Stewart Street in Sandy Hill. These retrofit projects allow runoff on an otherwise paved surface to infiltrate back into the ground. Hiding underneath the perennials and flowerbeds is a complex drainage system, monitored and maintained by City staff.

Newer areas

In neighbourhoods built in the 1980s and later, runoff is being collected in stormwater ponds that drain to a nearby waterway. The man-made ponds slow down the flow so that dirt and other pollutants can settle. Cleaner water leaves the ponds at a controlled rate, and there is less danger of flooding and erosion. These days, stormwater management infrastructure is required for every new suburban development.