North Fork Matilija Creek: A Model for Environmentally Nuanced Restoration Projects

The California Department of Transportation (Caltrans) District 7 North Fork Matilija Creek (NFMC) Geomorphology, Fish Passage, and Engineering Project protects local steelhead trout habitat while repairing erosion along State Route 33. This project was unique in that the existing step-pool system provided excellent rearing habitat for juvenile steelhead. The steepness of the canyon limited the potential approaches that would be compliant with existing environmental guidelines. Engineers demonstrated that although the 5-foot drops were outside the recommendations of the design manuals, they were within the steelheads’ capabilities. After demonstrating that adult fish could pass through the step-pools, further analysis determined that the channel widening would not fill the juvenile rearing pools with sediment. Trees, riparian habitat, and habitat structures were added to keep the stream cool and provide cover and shelter for the fish. The system protects the juvenile fish rearing pools and will help the steelhead population increase within the creek.