Logjam project gearing up

Published 2:38 pm Thursday, October 2, 2008

SNOQUALMIE — Reinforcement is coming for

flood-ravaged banks along a section of the Snoqualmie River in

August. Manmade logjams and fiber-covered fill will be used to shore up the

badly eroded riverbanks and reclaim lost ground.

The project is being funded by an $800,000 federal grant obtained by

the city in 1997 from Housing and Urban Development (HUD)

sources. Snoqualmie Assistant Planner Mike McCarty said it has taken three

years to develop the design and gain the permits. King County has agreed

to act as project manager throughout the course of construction.

Three logjams will be placed in the river along city-side banks

between the Meadowbrook Bridge and River Street. Although the structures will

not prevent flooding, they will act as a stopgap measure to divert

fast-flowing water while plant and tree growth reestablishes itself as a natural

barrier to further erosion.

The logjams, each 200 to 300 feet long by up to 30 feet in width, will

be constructed of river drift logs and salvage material from various

King County projects. Several other sections of the bank will be covered

with coir, a natural fiber fabric that will secure fill dirt during the plant

establishment period. The coir is biodegradable and disintegrates over time.

“Pilings will anchor the logjams to the bank,” Tom Bean, senior

engineer for the project, explained. “We

don’t anticipate any debris-accumulation problems because the logjams will

be 20 feet below the high-water level. Any flood-borne debris would

be higher and would not get caught up in the jams.”

Construction is scheduled to begin the second week in August

and must be completed by Oct. 15. Noise from piledrivers and other

equipment will be substantial. In accordance with Snoqualmie ordinances, work is

restricted to; 7 a.m. to 10 p.m. Monday through Fridays, 8 a.m. to 10 p.m.

Saturdays and 9 a.m. to 10 p.m. on Sundays.

“We want people to know that the piledriver noise won’t last forever,

and we apologize in advance because it will disturb the peace and quiet

somewhat,” Bean said. “We will comply with the city timing restrictions

and we will work as quickly as possible to stop the racket.”

“We need to restore the riverbank lost over years of flooding and

erosion,” City Manager Gary Armstrong added. “The piledrivers and

permits are controlled by fisheries, so we only have this window of opportunity

(until Oct. 15) to complete the project.”

Along with reclamation and erosion control, the project will help

restore fish habitat in the affected section.

“As with any construction, there will be minor inconveniences, so

we ask that the community bear with us and we will finish the project

as quickly as possible with the least impact to citizens,” Armstrong

concluded.