Expect climate change to cause more flooding of the Red Hill Valley Parkway: report

A new report says flooding concerns around the Red Hill Valley Parkway have materialized, with the highway already withstanding one 100-year storm and more likely on the way.

The report came with 22 recommendations

A new report shows warns the city to keep a close eye on potential flooding of the Red Hill Valley Parkway. (Samantha Craggs/CBC)

The city should keep a close eye on flooding around the Red Hill Valley Parkway, a new report says, which is built to withstand "100-year storms" that are becoming more frequent.

The report, compiled by Wood consulting, painted a positive picture of the environment around the 11-year-old highway, including 42 bird and four amphibian species in the valley.

But flooding has been an issue. The highway is designed to withstand a 100-year storm event, said Matthew Senior, a senior engineer with Wood. And the city should prepare for more.

The valley saw a storm "well in excess" of a 100-year storm in 2009, Senior said. And it narrowly missed a 2012 storm, which was "1.5 times a 100-year storm event." The area also flooded twice in 2010, although Wood said that flooding was caused by a grill.

The city needs to monitor where flooding happens and how to prevent it in the future, Senior said.

Senior presented these findings to city council's public works committee on Monday. The report was a final five-year environmental assessment, mandated by the government bodies that approved the construction of the 11-year-old highway.

The report recommends the city continue a monitoring program around the Davis Creek Flood Control Facility, which still hasn't been commissioned.

It also recommends the city "monitor and assess localized flooding locations" and come up with a list of ways to remediate them. It also suggests the city and province "undertake a climate change assessment" to "better understand the potential vulnerabilities along the RHVP."

This comes as no surprise to Don McLean, an environmentalist who fought the highway for years. Even in the late 1990s, McLean said, studies showed climate change would cause more extreme storms in Hamilton.

The Red Hill is vulnerable, he said. Parts of the eight-kilometre highway are built on a floodplain. When it was built, it realigned more than seven kilometres of Red Hill Creek.

McLean said 100-year storms are becoming a more frequent occurrence. It stands to reason the highway will be impacted.

"We've certainly seen that accelerating," he said of extreme weather. "There's no reason to believe that won't accelerate more."

Overall, the report came with 22 recommendations, including the following:

  • Continue to monitor ground and surface water levels, water quality, erosion, vegetation and turtle populations. 
  • Hold "clean out days" to clean up the creek and encourage the community to participate.
  • Consider transplanting native fish.
  • Consider carp control in the lower wetlands and marshes. Look at the need for more restoration of the valley and the species that grow there.

Chad Collins, Ward 5 councillor, asked staff to report back on what measures aren't funded. He also successfully pushed for a $25,000 grant for the volunteer-based group Stewards of the Red Hill Watershed $25,000 to support their clean-up work.

Coun. Sam Merulla of Ward 4 saw it as a positive report overall. The findings, he said, can be "deduced into a simple message that everything is working."

It shows that "what we've done is everything that's right and what's been said in the past is actually wrong."

About the Author

Samantha Craggs

Reporter

Samantha Craggs is a CBC News reporter based in Hamilton, Ont. She has a particular interest in politics and social justice stories, and tweets live from Hamilton city hall. Follow her on Twitter at @SamCraggsCBC, or email her at samantha.craggs@cbc.ca