A key part of Calgary's pathway system has reopened in the southeast after being badly damaged in the flood.

The pathway under the Bonnybrook Bridge partially collapsed forcing cyclists onto Ogden Road.

"This particular closure results in about a five and a half kilometre detour," said Duane Sutherland from Calgary Parks.

Bike Calgary spokesperson Brent Clark said these repairs are vital to the city.

"The critical thing to remind ourselves of is, those pathways are really the only connections from some of these communities throughout the city. Without the pathways, there's really none of those safe, comfortable connections."

The city estimates more than 90 kilometres of pathways were damaged or closed by the flood originally.

That is down to 30 kilometres now.

There is no specific figure on how much it will cost to repair the pathway system, but it is expected to be millions of dollars.