Dry Creek flood mitigation close to complete

Third avenue: | Port Alberni will complete $2 million worth of flood protection and salmon enhancement work in mid-October.

The former Jade Restaurant was demolished on Aug. 29 to make way for the city’s Dry Creek flood mitigation work.

The work to protect lower Third Avenue from winter flooding is three-quarters of the way complete, according to city engineer Guy Cicon. The contract was award to Bowerman Excavating Ltd. earlier this year.

The Jade Restaurant, which the city purchased in July, was demolished on Aug. 29, making way for a new box culvert to be installed underneath the Restaurant Bridge at Third Avenue.

“That increases the cross-sectional area of the bridge to allow more flow to go through,” said Cicon.

“If you didn’t have that then you’d have a restriction. We have to increase the area to improve the flow.”

The restricted flow under the Restaurant Bridge (which was located beside the Jade) is part of the reason behind the repeated flooding of Third Avenue, Cicon said.

“That flow restriction is one of the causes of the flooding.”

Channel improvements along the entire length of Dry Creek, which flows underneath Restaurant Bridge, will deal with the other causes of the flooding.

“We’re doing channel improvements to improve the flow,” said Cicon.

This work also extends behind Smitty’s on the opposite side of Third Avenue and all the way back to approximately Bute Street.

“The existing channel cross-section isn’t big enough either so we’re enlarging the downstream channel.”

The width of the channel will increase from six to seven metres previously to 12 metres once construction is complete.

“It’s nearly doubling it.”

Widening the channel will include steepening the banks.

“We’re using gabion baskets so that allows steeper banks and more cross-sectional flow,” Cicon said.

Gabion baskets are riprap covered in wire or metal and designed to decrease erosion of stream banks.

It’s not just Port Alberni’s human residents that will benefit from the flood mitigation.

“We’re digging fish habitat pools,” said Cicon.

“They’re being installed upstream of Fourth Avenue [inside Dry Creek Park]  for salmon habitat enhancement.”

The work is being supported by West Coast Aquatic.

According to Cicon, no modification of Dry Creek could be done without considering the salmon.

“You can’t do one without the other,” he added.

“A stream is inherently linked to the environment… engineering the flood protection isn’t independent of everything else. They go hand in hand.”

The grant funding that the city received (one-third each from the provincial and federal governments) required the city to show an environmental benefit as well.

“A project like this with grant funding must demonstrate an improvement to the environment,” Cicon said.

As part of that, there’s a low flow channel being carved into the bottom of the creek bed.

“It’s a carved ditch in the bottom of the ditch,” said Cicon.

“In very low flows, water is concentrated in a low flow channel so that fish can more easily move from one habitat pool to the other.”

A wider channel on the other hand means low water levels.

“If it was just a 12-metre wide  bottom, the water would be really shallow.”

The low flow channel will be about one metre in width, Cicon added.

One of the problems encountered with this summer’s drought  was fish pools drying up in city creeks. Sheena Falconer from West Coast Aquatic spent part of her summer relocating fish because of low flows. The low flow channel is designed to help alleviate this situation in future years.

Along with the salmon enhancement work, they will also do some general environmental restoration of Dry Creek’s banks.

“We’ll be doing  some restoration  work as well, including planting native vegetation like cedar, fir and salal,” Cicon said.

“It’s all about combining flood improvements with habitat improvements.”

The work should be completed by mid-October, before the winter storms and flooding it’s designed to mitigate.

Cicon hopes that the work to improve the creek’s flow will eliminate the

flooding that has plagued lower Third Avenue.

“The amount of water won’t change, it’s just how we’re managing that water.”

reporter@albernivalleynews.com

twitter.com/AlberniNews

Just Posted

Tsunami warning prompts evacuations in Port Alberni

Alaska earthquake prompted warning for coastal BC

Tsunami warning prompts Alberni’s Best Western Barclay hotel to evacuate 55 rooms

Guests were evacuated to the Alberni Valley Multiplex early Tuesday morning

UPDATE: Tsunami warning cancelled for coastal British Columbia

Warning issued following 7.9 earthquake off Kodiak, AK

COUNCIL WATCH: Here are some of the stories we’ll be following

Traffic counts, a Nuisance Property Working Group and more at Alberni council meeting

Stakeholders tackle poverty in Port Alberni

Residents invited to share ideas for solution at Tuesday (Jan. 23) meeting

Testing the Google Arts & Culture app

Going face to face with art

Vancouver Islanders ponder need for tsunami siren song

Alarm sounds in Port Alberni but not at the DND base in Esquimalt

Babcock, Goyette and Smyth honoured at Order of Hockey in Canada

Mike Babcock, from Saskatoon, guided the Detroit Red Wings to a Stanley Cup in 2008

Bell Canada alerts customers who may be affected by latest data breach

Federal Office of the Privacy Commissioner said it had been notified

‘The tsunami alarm failed my household’: North Coast residents concerned over sirens, alerts

People living in northern communities share how they learned about Tuesday’s tsunami warning

Snowboarder dies at Vancouver Island ski resort

Death at Mount Washington Alpine Resort

Man faces 48 charges in string of random Toronto shootings

The string of unprovoked shootings began Jan.9, say police

‘Shape of Water’ producer, Christopher Plummer among Canadian Oscar nominees

Guillermo del Toro film about merman romance earns 13 nominations

Most Read