Olalla Creek and Tributaries Fish Passage and Enhancement Project

Olalla Creek and three tributaries, located in the southern part of the Olalla-Lookingglass Creek Watershed, are in need of improved fish passage and fish habitat enhancement. The project proposes to 1) replace the Bushnell Creek and Old Lane Creek culverts to restore fish access to upstream habitat, 2) Place large wood into Byron Creek on private and BLM land to improve instream fish habitat, and 3) plant willow wattles along streambank sections in Olalla and Byron Creeks.

The results of this restoration project are expected to benefit all aquatic species present in Olalla, Byron, Bushnell and Old Lane Creeks through large wood placement, willow planting and replacing two failing culverts. Planting of willow wattles will help to prevent further soil erosion, help with bank stabilization, provide shade, stream roughness and help to lower turbidity levels. As they grow, they will create cover for fish to hide from predators and will provide a food source for juvenile fish. As more food is made available for juvenile salmonids, they will become larger and their survival rate greatly increases. Restoring fish passage in Bushnell and Old Lane Creeks will open up high- medium intrinsic potential habitat for fish. This is critical habitat for the recovery of OC coho salmon and steelhead. Fish habitat structures are designed to improve summer and winter instream habitat conditions because there will be a substantial increase in cover habitat and through time more pools will become available as the logs induce scour and deposition. Residual pool depth will increase, and water temperatures will decrease as a result of increased hyporheic water retention in the floodplain. Coarse substrate will accumulate and begin to create quality spawning riffles. The structures will also provide cover for juvenile salmonids and other native fish species.