A short, sharp downpour flooded Ashburton businesses, ruined 200 library books and caused sewage to overflow.

Up to 30mm of rain fell in 15 minutes on Saturday afternoon, causing havoc for local businesses and surface flooding on some Ashburton streets.

Ashburton Public Library manager Jill Watson said it was the worst flooding in the building she had seen in her 48 years of working there.

However, she hoped it would be the last.

The library is set to close on November 26 to start its shift to the new Te Whare Whakatere, Ashburton Library and Civic Centre, which is set to open on December 18.

Council people and facilities general manager Sarah Mosley said that at least 200 books would not make the trip after being damaged by the leaky roof.

It made for a different kind of hum at the library on Monday.

“We have dehumidifiers working flat out to dry out wet carpet tiles,” Mosley said.

The old library, which opened in 1967, wasn’t alone in suffering from the storm's rapid downpour.

Across town at the River Crossing retail precinct, which opened just over a year ago, the Kmart had to close after water began leaking near the entrance.

“The guttering got overwhelmed and it flooded into the building,” Tricroft general manager Tony Gilbert said.

“That amount of water in a short space of time, it got overwhelmed.

“The fact there were so many other buildings with similar issues shows that it was quite a volume of water.”

Formosa Restaurant's roof leak was so damaging the business remained closed on Monday for repairs.

Nearby Cleavers Corner Gastro Pub had the surface flooding breach its doors requiring a clean-up to open on Sunday, and around the corner, the F45 gym was completely flooded and remained closed on Monday.

Several roads resembled rivers from the deluge on Saturday.

Ashburton resident Margaret Anderson said it “was like a river with water flowing along the road" at the intersection of SH1/West Street and SH77/Moore Street.

Surface flooding led to raw sewerage flowing along William Street.

Council infrastructure and open space general manager Neil McCann said the problem occurred where council contractors were putting in new wastewater pipes.

“The site was inundated with stormwater that infiltrated the wastewater system and caused an overflow. 

“The site has been cleaned up and disinfected by the contractor.

“Events like these have no impact on council’s drinking water network in Ashburton, and tap water remains safe to drink.”

The roading and stormwater networks have been checked and there was no major damage to report, he said.

“We had a few isolated spots where water pooled, as you would expect with a sudden heavy downpour.”

Meanwhile, Mid Canterbury’s run of troubled race meetings continued on Sunday with the Ashburton Racing Club meeting on Sunday abandoned due to surface water flooding both the track and stabling area following the weekend’s big rainfall.

It follows on from another meeting of the club’s being abandoned due to high winds last month and the Methven Trotting Club meeting 10 days ago being abandoned due to snowfall.

Sunday’s meeting has been shifted to Thursday with the same programme.

By Jonathan Leask