Written by Renton’s Public Works Administrator Greg Zimmerman recently wrote to King County expressing concern about chained-together piles of large woody debris upstream of Renton that threaten our bridges during flood events. I agree with Mr. Zimmerman’s assessment that these woody masses, or at least the chains binding them together, should be removed at once. The text of Mr. Zimmerman’s letter is below the first photo:
Cedar River upstream of Renton; Chained logs, placed in the river by the department of fisheries, are visible in the foreground of this photo (photo furnished to city by a citizen).
To: Mark Isaacson and Steve Bleifuhs at kingcounty.gov
Cc:Denis Law; Terri Briere; King Parker; Rich Zwicker; Don Persson; Greg Taylor; Marcie Palmer; Randy Corman; Jay B Covington; Terry Higashiyama; Todd Black; Ronald Straka; Lys L. Hornsby; Linda Moschetti
Mark and Steve:
You may be aware that we have evidence that the recent large log jam at Renton’s Riverview Park Pedestrian Bridge was caused once again by a chained large woody debris (LWD) mass placed into the Cedar river by King County. In the process of clearing the logjam that developed during the recent Phase 4 flooding of the Cedar River, our contractor found chained LWD wrapped around the bridge support toward the bottom of the logjam. It appears that this mass caused the logjam to accumulate. Of course we had a similar situation in 2009 when a chained LWD mass got lodged under our Williams Street Bridge. I have attached a letter in this regard, and also two photographs showing our contractor removing the LWD from the Riverview Bridge. I have attached three more photographs taken by citizens showing other chained LWD masses lying along the river between mileposts 6.5 and 7.5 that could be swept into the river during the next high flow event. These masses pose serious risks to both Renton’s bridges and the two bridges that the Boeing Company uses to move all of their 737 aircraft across the river to take their maiden flight from Renton Municipal Airport. We are urgently requesting that King County identify all chained LWD in or alongside the Cedar River and remove these masses, or at least remove the chains that link the logs together and present a greater hazard. This work should be done before the next high flow event in the river. Please see my attached letter and the photos for more information.
I can be reached at (425) 430-7311… I am requesting a timely response to this pressing issue. Thank you.
Sincerely,
Gregg Zimmerman, P.E.
Public Works Administrator
City of Renton
Above: Removal of the most recent log-jam last week at our Riverview Park Bridge. In a major flood event these log-jams can be very dangerous, as they will tend collect more and more logs and ultimately threaten the bridge and property downstream.
Above: The removed logs from the Riverview Park Bridge.
Above: In the above photo is from 2009, county workers cut the chain holding a logjam together under our Williams Street Bridge. Photo from this city newsletter.
The two photos below are other piles of “Large Woody Debris” chained together to form fish habitat by the Department of Fisheries. Renton worries that piles like these could be the next material to break loose in a flood and threaten one or more Renton bridges.
Recent Comments