This presentation was prepared to advise Green Communities Canada on the applicability of green infrastructure for flood risk reduction as part of the Ontario Urban Flooding Collaborative. It includes a review of the Intact Centre on Climate Adaptation's Laurel Creek watershed assessment (a case study in their 2017 report "When the Big Storms Hit: The Role of Wetlands to Limit Urban and Rural Flood Damage". The review suggests that the ICCA case study is atypical for both urban and rural areas in Ontario, meaning that opportunities for flood storage and damage reduction are more limited than suggested.

1. Wetland Review
Distribution of Wetland Features / Applicability
of Preservation / Restoration on a Broad Scale
for Urban Flood Risk Mitigation (review of
Intact Centre Laurel Creek example and typical
urban area / Ontario opportunities)
Robert J. Muir, M.A.Sc., P.Eng.
June 26, 2018

2. Laurel Creek / City of Waterloo (Intact Centre
Wetlands Report example site for flood control)
• High percentage of wetlands in Intact Centre study is atypical for Ontario
Wetlands and Subcatchments
per GRCA Open Data. Showing
% Wetland per Subcatchment.
Waterloo SPA

3. Laurel Creek / City of Waterloo (Intact Centre
Wetlands Report example site for flood control)
• High percentage of wetlands in Intact Centre study is atypical for Ontario
SOLRIS Land Use and Ontario
conditioned DEM.

4. Laurel Creek / City of Waterloo (Intact Centre
Wetlands Report example site for flood control)
• GRCA watershed
subcatchments have
low % wetlands in
urban areas
Subcatchments colour coded
by % wetlands in the Grand
River Watershed (KW Area).

5. Laurel Creek / City of Waterloo (Intact Centre
Wetlands Report example site for flood control)
• Guelph – Urban Area Has Low Wetland Potential
SOLRIS Land Use and Ontario
DEM flow paths in urban areas.

6. Laurel Creek / City of Waterloo (Intact Centre
Wetlands Report example site for flood control)
• Brantford – Urban Area Low Wetland Potential (Urban Area is a high point)
SOLRIS Land Use and Ontario
DEM flow paths in urban areas.

7. Laurel Creek / City of Waterloo (Intact Centre
Wetlands Report example site for flood control)
• Kitchener – Urban Area Has Low Wetland Potential (Sandrock Greenway)
SOLRIS Land Use and Ontario
DEM flow paths in urban areas.

8. Laurel Creek / City of Waterloo (Intact Centre
Wetlands Report example site for flood control)
• Fergus – Surrounding wetlands do not contribute to local urban drainage
SOLRIS Land Use and Ontario
DEM flow paths in urban areas.

9. Laurel Creek / City of Waterloo (Intact Centre
Wetlands Report example site for flood control)
• Mississauga / Malton – no wetlands contributing to urban area
SOLRIS Land Use and Ontario
DEM flow paths in urban areas.
Malton
Hwy 427
Hwy 401

10. Laurel Creek / City of Waterloo (Intact Centre
Wetlands Report example site for flood control)
• Markham - West Thornhill, Don Mills Channel no wetlands contributing
Hwy 404
Hwy 407

11. Laurel Creek / City of Waterloo (Intact Centre
Wetlands Report example site for flood control)
• High percentage of wetlands is
atypical for Ontario – Laurel Creek
17.6%
(86% of GRCA subcatchments have
lower wetland percentage – Laurel
Creek is not typical / average)
• Urban % wetland and
opportunities are much lower
• Intact Centre example has 540 ha
wetlands in 5631 ha basin – about
10% of land above SPA (ATYPICAL)
• Waterloo SPA flood damage
centre downstream is atypical
(construction of Laurel reservoir)

12. Peel/Toronto/York/Durham – low wetland contribution to local
urban catchments (1000’s of these are typically 10’s to a couple
100 hectares in size)
300+ Urban
Catchments in
Markham, Average 55
hectare size

13. Laurel Creek / City of Waterloo (Intact Centre
Wetlands Report example site for flood control)
• Region of Waterloo OP protects greenspace including Laurel Creek Headwaters
• City of Waterloo OP
Section 8.2.3 (5):
“Future expansions
of the Urban Area
Boundary are not
permitted into the
Laurel Creek
Headwaters
Environmentally
Sensitive
Landscape.”
https://www.waterloo.ca/en/contentresources/resources/government/OP_Nov2016
_Consolidated_version.pdf