The city will postpone work on the middle Colliery Dam until 2023 while data is gathered to redefine extreme flood danger for the Chase River. (News Bulletin file photo)

Further work postponed on middle Colliery Dam

New study suggests extreme flood flows might be less likely than previously estimated

The city will postpone further work on the middle Colliery Dam until at least 2023 while more data is gathered on the Chase River.

In a press release issued Tuesday morning, the city said the completion of the lower Colliery Dam auxiliary spillway partially address outstanding requirements from the Provincial Dam Safety Section order, which also required the city to address safety risks at the middle dam.

The city reviewed flood and seismic risks for the middle dam. The new study suggests that extreme flood flows through the middle dam might be lower than previously estimated.

“This new analysis takes advantage of river level data that wasn’t previously available,” said Poul Rosen, city senior manager of engineering, in the press release. “The additional data gained by continuing to monitor river levels will provide more certainty of the results and ensure that any future decisions on the middle dam can be made with confidence.”

The study looked at several years of river level data gathered through the early warning system installed at the dams in 2014 to make predictions about extreme flood events and also compared runoff rate data from other watersheds in the region to provide the basis for the decision to defer further risk assessment until 2023.

“Since this new model only uses a few years worth of data, it is not possible to make definitive predictions about extreme events,” Rosen said. “However, the lower flow results suggest that years of further data collection is warranted before any significant decisions are made or any potential future work at the middle dam planned.”

As a result of the study, the city and province agreed the best strategy regarding the middle dam will be to continue gathering river flow data for a hydrology model update in 2022.

For more information on the Colliery Dams visit

Just Posted

Silly boats make a splash on Nanaimo seas

Superette wins Nanaimo’s Silly Boat Regatta community fundraising event

Redliners park their rides for charity car show in Nanaimo

The Redliners Charity Car Show continues until 3 p.m. Sunday, July 15, at Country Club Centre

Florist announces bid for Nanaimo city council

Jim Turley, former owner of Turley’s Florist, intends to run in fall election

France doubles up Croatia 4-2 to win World Cup

Played in Moscow Russia, latest Fifa World Cup marks the highest scoring final since 1966

St. Andrew’s United Church celebrates 125th anniversary

Church on Fitzwilliam Street in Nanaimo to hold event July 18 to recognize milestone

VIDEO: Firefighters putting out brush fire in East Wellington

Fire is in the area of a new development under construction near Shady Mile Way

Motorcyclist dies as fire, crash happen at the same time on Nanaimo Parkway

Young male motorcycle rider collides with one vehicle, then struck by another

Development permit approved for condo project near Millstone River

Six-storey building planned for Barsby Avenue

Former NHL goalie Ray Emery drowns in Lake Ontario

Police say the 35-year-old’s death appears to be a ‘case of misadventure’

Air quality statement warns of smoky air for Kamloops area

Environment ministry says area on north side of Thompson River may be affected by wildfire smoke

Pussy Riot claims on-field protest at World Cup final

Russian protest group claimed responsibility after four people ran onto field in police uniforms

Fans party on Montreal streets after French World Cup win

To city is home to nearly 57,000 French nationals

Driver angry after accident at north Nanaimo intersection

One patient taken to hospital after crash Friday at Enterprise Way and the old Island Highway

VIDEO: Silly Boat sailors serious about trying to win regatta

Soggy Bottoms 4Kids, a Protection Island Lions Club entry, hope to take Nanaimo Silly Boat title

Most Read