Bowers Rock Phase II Implementation

The purpose of this project was to address connectivity issues within the gravel pond and sloughs at Bowers Rock State Park east of Albany, OR on the main-stem of the Willamette River. Due to three undersized culverts and a low-water ford, the gravel pond and east/west sloughs lacked connectivity. Additionally, an infestation of ludwigia within the gravel pit and throughout the sloughs was impacting availability of open water habitat and impacting water quality.
This project connected the gravel pit to the main-stem Willamette through enhancement of an existing floodplain channel at the southwest corner of the pond and by creating a broad swale to act as the outlet channel and disperse flow. Additionally, two undersized, failing culverts were replaced, one low water ford was improved, and another culvert was completely removed to increase fish access to the floodplain. Ludwigia in Coon Creek and the Little Willamette were treated and riparian revegetation was undertaken to mitigate disturbance associated with implementation.

A key limiting factor for DPS/ESU salmonids in the Willamette River is off channel habitat. Despite the numerous challenges facing Willamette River fish communities, there remain opportunities for preserving and enhancing river and off-channel habitats at several sites in the basin. Large wood, intact floodplain vegetation and connected off-channel areas provide the beneficial conditions conducive to recovering imperiled fish populations, and provide benefits to a myriad of other riparian-dependent species. Removal of barriers to the floodplain and increasing the hydraulic connectivity with the mainstem of the Willamette will provide enhanced off channel habitat for salmonids, addressing one of their primary limiting factors. Winter steelhead and spring Chinook salmon move through this reach during spawning migrations. Large wood and low velocity off-channel and channel margin habitats provide cover and resting areas for migratory fish. Out-migrating juvenile steelhead and salmon also benefit from these habitat features on the downstream migration to the Willamette River and ultimately the Pacific Ocean (Colvin et al. 2005). Addressing the culverts that are currently fish barriers to off-channel habitat will allow for additional habitat availability during high flows for Willamette River salmonids. The connection of the gravel pond will provide 40 acres and 33 days on average of connection and access for juvenile salmonids.