Tioga Creek Instream Restoration: Phase 4

Tioga Creek is a flashy coastal system that combines with Williams River to form the South Fork Coos River and provides critical habitat for salmon and steelhead as well as Pacific lamprey, cutthroat trout. It is a BLM Focus Watershed and a high priority subbasin in the Coos SAP due to the high number of high IP miles and anchor habitat for coho, chinook, and steelhead. Historic forest practices such as stream cleaning, riparian logging, and removal of conifers from draws have left degraded aquatic habitats with low wood loading and elevated stream temperatures, leading in the ODEQ 303(d) listing of Tioga. This proposed project will address stream complexity and water quality issues on the main Tioga Creek by installing 20 instream structures over 1.8 miles of mainstem Tioga Creek to improve stream complexity and water quality through a critical mainstem habitat reach. This project will leverage past instream restoration that has been completed immediately upstream for just over 5 miles to the farthest extent of anadromy on the mainstem Tioga Creek. Improving instream habitat to this upper habitat is a critical piece to the overall restoration goal for this subbasin.

The Tioga Creek Instream Restoration: Phase 4 project will improve mainstem stream complexity and water quality, specifically summer temperatures, through the installation of wood structures to promote essential instream habitat formation and reduce summer stream temperatures over 1.8 miles of critical spawning and rearing habitat in mainstem Tioga Creek. Large wood promotes the creation of essential habitat features such as secondary channels, eddies, and alcoves provide high velocity refugia critical for overwintering juveniles as well as deep, complex pools and cover habitat necessary for productive summer rearing. Large wood also encourages further large wood recruitment and gravel retention. Over time, these structures will alter the variability in hydraulic conditions resulting in the deposition and sorting of coarse sediment, improving spawning habitat and stream temperatures by blanketing areas of bedrock to reduce solar loading. Large wood structures and gravel deposits also play a role in nutrient cycling processes, such as nutrient retention and habitat diversity for benthic macroinvertebrates, to improve overall rearing conditions. These proposed actions are even more critical as this subbasin is likely to see warmer, drier summers and wetter winters. These shifts are predicted to increase stream temperatures during summer low flows, further stressing juvenile summer rearing habitat. The predicted shifts toward wetter winter winters may promote higher winter flows, increasing the importance of high velocity refugia available for overwintering juvenile salmonids. These proposed actions will cool summer stream temperatures over time to improve summer rearing habitat and create high velocity refugia to improve overwintering habitat.