Science Corner: The Rockwads Project - Enhancing Salmon Habitat in the Sacramento River.
To continue to address and support salmon during their critical freshwater life stages, the Sacramento River Settlement Contractors are moving ahead on opportunities that provide key refugia during the juveniles’ outward migration.
The Rockwads Project, which was first implemented in 2017, is currently being monitored by our scientist, Keith Marine, for the structures’ effectiveness in providing salmon places to feed and hide from predators.
Young salmon need specific, complex habitats to survive: areas with modest currents next to boulders, cobbles, and submerged wood/vegetation. Unfortunately, these ideal, shallow habitats are very limited in the deeper, bedrock-dominated channel of the Sacramento River, particularly from Keswick Dam through Redding.
What are "Rockwads"?
Rockwads were engineered based on observations of fisheries biologists working on the Sacramento River over the last 40 or so years that juvenile salmon will congregate around large underwater structures like boulders and large wood debris, and even bridge piers, that provide slower current conditions.
The objective is to expand habitat complexity and diversity for young salmon and steelhead in this critical stretch, especially near the highest spawning grounds for winter-run Chinook salmon.
Rockwads Phase I: 45 structures were installed in a deep channel near the South Bonnyview Road Bridge in Redding (2017 & 2023).
Rockwads Phase II: Proposed for installation next year in a deep area just upstream of the Posse Grounds boat ramp.
These sites are at the heart of the winter-run spawning grounds.
Monitoring and Next Steps
Rigorous pre- and post-project monitoring is essential to track fish responses and inform future restoration efforts. We are using high-definition sonar and underwater videography to collect data on how the fish use the rockwads.
Monitoring results will be available throughout 2026 and will continue as Phase II is constructed