Cottonwood construction continues

Published on Wed, Sep 18, 2013 by Ian Ferguson

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If the weather cooperates, residents near Cedar Avenue in the Cottonwood neighborhood of Birch Bay can look forward to some peace and quiet by mid-October, public works officials said. That’s when a construction project begun in late July is scheduled to wrap up.

Residents can expect better protection from flooding as well. Ingrid Enschede, program specialist for Whatcom County Public Works, said the modifications in the neighborhood are meant to prevent the type of flood damage that has affected the neighborhood in years past.

“The pipe that was there before was undersized, which led to breakages and caused flooding on the roads and lawns during winter storm events,” she said. “There should be a definite improvement in the infrastructure’s ability to transport high volumes of water out of the area during big storms.”

Birch Bay Watershed and Aquatic Resources Management (BBWARM), the stormwater management district for Birch Bay, is managing the $468,000 capital improvement project. Len Honcoop Gravel, Inc. of Lynden is the contractor.

Crews are currently digging an 11-foot-deep trench to lay an outfall pipe along Cedar Avenue. The deep trench is necessary to maintain a moderate slope to the pipe as it heads back into the hill towards Anderson Road, said Whatcom County Public Works senior planner Kraig Olason.

“We’re hoping to connect that pipe to the primary bypass by the end of the week,” he said. The drainage crosses Cedar Avenue just south of Alder Street and empties into a confluence before directing water into an outflow pipe to the beach.

At the confluence, crews are also installing a treatment swale – an area where planted soils filter out contaminants in the runoff before it goes to the beach. A variety of grasses and plants, combined with amended soils and drainage rocks below the swale, will help to catch nutrients and other pollutants in the stormwater.

Cottonwood beach was plagued with algae and purple, smelly bacteria in late July, as it often is during the warm summer months. 

Enschede said the algae and bacteria are a result of a combination of regional factors: high nutrient levels and water temperatures throughout Birch Bay, as well as currents that push algae into the Cottonwood area.

While the treatment swale filtering the relatively small amount of water flowing to the beach from the Cottonwood area won’t fix the problem, “It’s one piece of the puzzle to improve water quality in the whole area,” Enschede said.