A large portion of the Bow River pathway in the city's northwest closed on Monday, and will remain that way until mid-October, leaving some daily users in "shock" and looking for a new route.

The closure extends between 14th Street and 29th Street N.W. on the north side of the Bow River.

The city said the pathway storm water system needs upgrading because of damage to outfalls and storm water trunks during the 2013 flood.

Kevin Colbran, manager of infrastructure delivery for the city of Calgary, says they've been posting signs and informing community groups of the impending closures since May.

"The detour has been well established, it's well signed," he said. "Notifications went to the community associations and we've been working with the ward offices and user groups to let them know this was coming."

Kevin Colbran is the manager of infrastructure delivery for the City of Calgary. (City of Calgary)

But Calgarians like Christine McCabe — who use the pathway daily — say they were unaware of the specific closure.

"[I'm in] absolute shock and surprise because I came this way this morning and it was not blocked off," McCabe told CBC on Monday.

"The pathway closures, as I understood them, was just the underpass at Crowchild. So I've been using this all summer and expected to be able to use it for the duration, it's kind of like, whoops, now I have to find an alternate way home."

Christine McCabe says she was only aware of the closure at the Crowchild underpass, and was surprised Monday evening by the other closure. (James Young/CBC)

Nick Winnick says he didn't see any signs indicating the pathway would be closed.

"Particularly not any signs far ahead enough along the path that would let me choose an alternate route," he said

Winnick says he checked the signs a few weeks back and they only mentioned the closure of the pathway by the Crowchild Trail underpass.

Nick Winnick says he feels the city could have better communicated the closure. (James Young/CBC)

"If there have been any amendments to those signs in the intervening time, I haven't been checking to see if the signs are different every day," he said.

Calgarians voiced their frustrations with the closure on social media, saying the closure wasn't posted to the city's website.

"Absolutely no info on the Bow River pathway closure along Parkdale Blvd., nor through your Twitter account. No signage at all. Who is responsible for this oversight?" tweeted Russ Koehler.

⁦<a href="https://twitter.com/cityofcalgary?ref_src=twsrc%5Etfw">@cityofcalgary</a>⁩ Absolutely no info on the Bow River pathway closure along Parkdale Blvd nor through your twitter account. No signage at all. Who is responsible for this oversight? <a href="https://t.co/xjWa01uqO6">https://t.co/xjWa01uqO6</a> —@rkoehler

If the <a href="https://twitter.com/cityofcalgary?ref_src=twsrc%5Etfw">@cityofcalgary</a> claims to have communicated this closure well, how come <a href="https://twitter.com/CalgaryParks?ref_src=twsrc%5Etfw">@CalgaryParks</a> hasn't updated their Pathways Closures and Detours web page since July 5? Pathway is closed yet not mention on web page OR interactive map online. —@SeumasBruce

Winnick says he thinks the city could have done a better job of communicating closures as they happen.

"With the amount of effort the city has in general been putting into ensuring these pathways are a viable commuting alternative, it seems kind of at odds with that philosophy," he said. "You would think that if they really want to encourage bike commuting this would be the sort of thing that is better communicated."

McCabe said now that she knows about the closure, she'll be able to find a better route for the next few months.

And, she appreciates the work the city is putting in to keep the paths in good shape.

The City's map of the closure and schedule for the Bow River pathway upgrades.

"The city is doing what they have to do," she said. "Infrastructure maintenance is important."

Colbran said unfortunately, where the current closures are the only viable detour was on the street.

"It's really the only option there," he said.

But, he said they'll be waiting for feedback from pathway users to 311, and making changes as needed.

Colbran said safety is the city's number one priority.

"I would encourage folks that they certainly need to follow the rules of the road, and the signage that we have out in place and to be careful," he said.