Ottawa

NCC paths fared better after 2019 floods, but may have to move

The National Capital Commission had to fight another round with the Ottawa River this spring, but this time it was closer to a draw, costing less time and money in repairs.

After 2017 flooding, pathways were rebuilt to better withstand rising waters

Jamie Brown, the NCC's senior landscape architect, oversaw repairs in 2017 and 2019. He said strengthened pathways held up much better after this year's flooding. (Ryan Tumilty/CBC)

The National Capital Commission (NCC) had to fight another round with the Ottawa River this spring, but this time it was closer to a draw, costing less time and money in repairs.

Many of the commission's paths were under water in 2019, just as they had been in 2017, but when the water receded this time around, the cleanup and repairs weren't so bad.

"The damage was surface damage. We were able to fix the pathway within three or four weeks, instead of having it be closed for entire season like it was in 2017," said Jamie Brown, a senior landscape architect with the NCC.

"In 2017, we had major washouts of entire sections of pathway."

The pathway behind Parliament Hill was submerged during the flood in April 2019. (Ian Black/CBC)

It cost the NCC nearly $2 million to repair paths in 2017. So far this year, the bill is $250,000.

In terms of time, it took as much as a year and a half to repair some paths after the 2017 floods, but this year most paths are set to reopen within two months of the waters receding on June 4.

Brown said that's largely because of the large rocks — called riprap — the NCC laid down alongside native plants that are more resistant to flooding and erosion.

"It resists the currents significantly better. It resists the ice in the water system significantly better. It's a much more stable way to have a fairly natural shoreline, but also create the stability and the resiliency we're looking for," he said.

Ideally the plants would have had three to five years to establish strong root systems, but they held up against the water.

"They got tested earlier than we would have liked but we're still happy with the results," Brown said.

Construction work included more minor repairs in 2019 than in 2017. (@tobi_nussbaum/Twitter)

Paths may have to move

Up until now the commission has rebuilt and reinforced pathways, but Brown said they may have to look at moving them if floods become more frequent.

"There will be places where the pathway can be moved out of the two- or five-year floodplain. It can also be moved out of the 25-year [floodplain] in some sections and there's a few other sections where we can actually get it out of the 100-year flood line," Brown said.

One thing the NCC is not considering is raising pathways, because raising them could push more water into communities. 

"You have to be very careful to changing the floodplain because there can be unintended consequences downstream very quickly," Brown said.

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