The £10m North Renfrew Flood Prevention Scheme, launched in 2016 and designed to protect against extreme flooding, was not fully deployed when Storm Boelo hit. The scheme includes a three-metre high embankment and an underground pumping station. While the pumping station was in operation, the flood barriers remained down.
A Renfrewshire Council spokesperson said: "The available forecast data and information for the severe weather at the weekend, which included the predicted tide levels for the Clyde, did not meet the currently set threshold for activating the flood barriers in Renfrew. Unfortunately, the water levels which affected various locations on the estuary, raised significantly above predicted levels resulting in some local flooding."
The council added that it would "review the arrangements in place to ensure these procedures reflect the impacts of a changing climate environment."
Local business owners described the sudden flooding as devastating. Maureen Gray, who works at the Ferry Nice Food takeaway on Ferry Road, said: "The damage is devastating. It was very sudden, within 15 to 20 minutes we were knee deep in the water. The banks broke and it was gushing in. It's absolutely terrible the barriers weren't used. We've never actually seen them used before and all that money was spent on it."
Gray said insurance would not cover the business because it is in a flood area. Some businesses had requested sandbags ahead of the storm but the council had not provided them.
Tarun Wadhwa, who runs the Green Gates Indian Restaurant, said: "It was a disaster. I have never seen the water like that before. This will be a big loss for me financially." He hopes to reopen by Tuesday or Wednesday.
The flooding came as tens of thousands of homes across Scotland remained without power after Storm Boelo, which brought wind gusts of up to 85mph (137km/h) in some areas.