Public Works

Public Works Blog

With river construction comes underwater sound monitoring

Posted On: August 12, 2020

In-water work begins July 15 on West Cashmere Bridge project

(Photos were taken by The Greenbusch Group, Inc., of Seattle, the consultant doing the acoustical and audio work on the West Cashmere Bridge Replacement Project. The top photo shows the hydrophone in the Wenatchee River. Bottom photo shows the diesel hammer that was used to drive a piling into the river.)

 

When building a bridge, oftentimes extra care is taken to lessen the impacts of a large construction project on the businesses and neighbors in the project area. From watering the work site to control dust to implementing night-time road closures to avoid high traffic, steps are taken regularly with our neighbors in mind.

The same sort of consideration extends to the fish making their home in the river below the work area.

At the West Cashmere Bridge replacement project, you might get the chance to see an “acoustician” on site when the contractor is driving steel pilings into the riverbed using a large diesel hammer.

An acoustician monitors noise levels in the water so work can be stopped if the noise created is high enough to injure or kill fish in the river. When underwater sound pressure injures a fish, this is called “barotrauma.”

Sound monitoring is especially important in rivers with federally protected endangered species, such as the Wenatchee River. The river is home to bull trout, spring chinook salmon and summer steelhead.

Noise is monitored using a hydrophone, or an underwater microphone. In Cashmere, the hydrophone will be lowered into the water from a platform under the West Cashmere Bridge. Measuring is done about 30 feet from any impact hammer pile driving. If the noise level is too loud, work is stopped and adjustments are made, such as adding a wooden cushion block under the hammer.

A variety of factors can come into play when measuring noise underwater. Deeper water creates higher noise levels. (The deeper the water, the more contact with the pilings.) The rockier the riverbed, the more resistance – and noise – experienced when driving piles.

So far, Chelan County’s contractor on the Cashmere bridge project has been able to use vibratory pile driving when embedding the majority of steel pilings needed to build a temporary work trestle. Vibratory pile driving produces a continuous sound, with peak pressures lower than pulses generated by impact pile driving. The vibration method is easier on everyone – from the contractor to the fish.

A variety of state and federal agencies require noise monitoring if pile driving will be done when endangered species are present. But doing so is just good stewardship. In Chelan County, we place a high value on our rivers and streams and the wildlife that depend on them.

Share This Page...

Older Articles

In-water work begins July 15 on West Cashmere Bridge project

Posted On: July 13, 2020

In-water work begins July 15 on West Cashmere Bridge project

With in-water construction related to the West Cashmere Bridge replacement project scheduled to begin July 15, Chelan County reminds recreationists on...

Read More arrow_forward

Will the chip sealing crew be in your area this summer?

Posted On: June 15, 2020

Will the chip sealing crew be in your area this summer?

This year, the county road crew starts chip sealing the week of June 22. Do you know if they'll be on your street?...

Read More arrow_forward

Road crews hit the road with COVID precautions in place

Posted On: June 04, 2020

Road crews hit the road with COVID precautions in place

Chelan County road crews are back on the road in full force after more than two months of working with reduced crew sizes during the governor’s Stay H...

Read More arrow_forward

Headed to the MRWF? Secure that load for safe travels!

Posted On: December 11, 2019

Headed to the MRWF? Secure that load for safe travels!

The new Chelan County Moderate Risk Waste Facility is open to the public. The facility is at 3612 Highway 97A in Wenatchee....

Read More arrow_forward

Code of the West: A reminder that life is different in the country

Posted On: September 06, 2019

Code of the West: A reminder that life is different in the country

The Code of the West was adopted in 2002 by Chelan County commissioners. It is not a formal code, but rather a philosophy or friendly advice for peopl...

Read More arrow_forward

It's always wise to stay off the (wet) lines

Posted On: June 18, 2019


It's always wise to stay off the (wet) lines

Roadway striping plays a valuable role in efforts to keep travelers safe on the roadway. The Traffic Safety crew of Chelan County Public Works re-stri...

Read More arrow_forward

In an emergency, don't let your address delay help from reaching you

Posted On: January 15, 2019

In an emergency, don't let your address delay help from reaching you

Have you ever asked yourself the question: When seconds count, how easily will emergency responders be able to find my home? Learn how your address ma...

Read More arrow_forward

Winter is coming -- it's time to remove any vehicles parked along the roadside

Posted On: November 08, 2018

Winter is coming -- it's time to remove any vehicles parked along the roadside

With Chelan County Public Works now preparing for winter and the inevitable snowfall that will come with it, our road crews are asking residents to re...

Read More arrow_forward

Preserving a piece of Cashmere's history

Posted On: October 22, 2018


Preserving a piece of Cashmere's history

Those people interested in giving the West Cashmere Bridge a new home -- and preserving its history -- have until Jan. 1, 2019, to contact Chelan Coun...

Read More arrow_forward

Need wood chips? Pick them up at the Chelan Transfer Station

Posted On: September 07, 2018

Need wood chips? Pick them up at the Chelan Transfer Station

Free shredded wood chips are available at the Chelan Transfer Station until about early October....

Read More arrow_forward

Chelan County Calendar

Upcoming events and schedules at the county!

  • 12
    Sep 2020
    09:00 AM - 01:00 PM

    September Parenting Class - English and Spanish

    Posted by: Superior Court Clerk

    Supporting Children Through Divorce is a four-hour educational program designed to help parents focus on the needs of their children during and after divorce and separation.

    Washington State University Extension
  • 08
    Sep 2020
    06:30 PM - 08:00 PM

    Chelan County Noxious Weed Board Meeting - 3rd Quarter

    Posted by: Noxious Weed Control Board

    Chelan County Noxious Weed Board Meeting

    Noxious Weed Conference Room
  • 02
    Sep 2020
    09:00 AM - 03:00 PM

    Hearing Examiner - September 2, 2020

    Posted by: Community Development

    Chelan County Administrative Building
  • 26
    Aug 2020
    07:00 PM - 09:00 PM

    Planning Commission - August 26, 2020

    Posted by: Community Development

    400 Douglas Street
  • 19
    Aug 2020
    01:00 PM - 03:00 PM

    Hearing Examiner - August 19, 2020

    Posted by: Community Development

    Chelan County Administrative Building