Quillayute Restoration Project Reach 3
The Quillayute River had consolidated to a single channel incapable of handling high flow events common to the valley. In November of 2021, the port city of La Push flooded due to floodwaters having nowhere to go. The event heavily eroded and undermined Mora Rd which protects La Push from Pacific storm events and is the only access to the sea dike.
BCI Contracting was tasked with implementing a design that enticed the Quillayute River to spread out into numerous side channels across the valley during high flow events. The new channels would greatly reduce the likelihood of flooding and infrastructure damage. These channels would also create habitat for Coho, Chinook, Sockeye Salmon, as well as runs of Steelhead during winter and summer.
The design also called for the repair of the highly eroded and failing river bank and constructing a continuous log jam wall.
Site Conditions
Reach 3 of the Quillayute River is tidally influenced with tides reaching over 10'. Access for equipment was by barge and staff was by flat bottom jet boats due to a water depth that varied between inches deep to over ten feet deep throughout the day.
Tidal activity influenced operations on a daily basis. Several key engineered log jam structures would become inundate with water during higher tides creating a need for either isolation walls with large pump systems or a work schedule that kept operations limited to lower tides.
Subsurface gravel compaction was extremely high and thought to be glacial till.
Means and Methods
The extremely compact subsurface gravels required highly specialized equipment to achieve the wood pile driving goals. Driving depths of 30’ using 30” diameter wood pile were required to secure the engineered log jams. To-date, pile of that diameter or smaller had not been successfully driven to 30' of depth.
To achieve this goal BCI developed two highly efficient light weight masts that were mounted to excavators. One mast held a drill that drilled holes 24’ in depth and the other held a hammer that drove pile up to another 10’ in depth. In the course of operations, pile of 30” to 42” in diameter was set to depth using these methods.
In order to mobilize the equipment to site, a barge design had to be created that was both extremely powerful yet relatively light weight because only a small barge could operate in this area and only at the highest of tides.
Operations in a highly tidal zone also required the creation of isolation berms and high volume pump systems to allow work to progress as efficiently as possible.
Final Results
BCI successfully drove nearly 300 30" and larger diameter wood pile to support eight large engineered log jams and forty small engineered log jams. These structures combined with the new channel excavations braided the river out creating outstanding new habitat and dissipating much of the energy previously exerted on failing river banks.
Within weeks of completion a fifty-year high flow event occurred with no flooding of La Push and excellent braiding of the Quillayute River throughout Reach 3.