Whitworth - Upper Patterson-Big Springs Restoration Project

Idaho Department of Fish and Game (IDFG) will improve habitat complexity on 1.57 miles of upper Patterson-Big Springs Creek near the town of May, ID. This project is the first phase of a two-phase project on Patterson Big Springs, with the downstream reach planned for construction in 2023. The Patterson-Big Springs phases are part of a multi-project habitat restoration effort on the Big Springs Creek Ranch with several projects completed and future projects proposed through 2025. Current habitat conditions include a spring channel with limited instream habitat and channel complexity, disengaged lateral habitat, and degraded riparian habitat. Project objectives include increasing both habitat and channel complexity and establishing increased lateral connectivity on the floodplain, existing disconnected side channels, and proposed excavated side channels to increase channel length and restore natural riverine and floodplain processes and function. Multiple project actions are prescribed to meet these objectives, and these include: 1) installing several types of large and small woody debris in upper Patterson-Big Springs to improve instream habitat for juvenile salmonids and improve channel complexity by creating roughness and reducing velocities throughout the project reach. 2) Utilizing both large wood, engineered riffles, and brush mattresses (under ‘other engineered structures’ in metrics) to raise grade and force a proportion of the flow into side channels and on the floodplain. 3) Utilize existing disconnected and proposed excavated network of braided side channels to increase overall channel length, and lateral habitat connectivity. 4) Native riparian revegetation will enhance riparian condition, help stabilize banks, and provide long-term habitat and water temperature benefits to fish.





The project will increase habitat capacity for juvenile salmon and steelhead. IDFG is working



with the Bureau of Reclamation (USBR) to develop designs, incorporating an aggressive



approach to fish habitat and floodplain connectivity. The landowner is allowing utilization of



a large portion of the property (under a conservation easement) for this purpose.

Rehabilitating upper Patterson-Big Springs as part of a multi-project effort to improve floodplain and riverine processes and functions on several springs as well as mainstem Pahsimeroi on this property will directly increase habitat capacity for juvenile salmonids. Under the proposed project, current conditions will be improved by restoring instream channel habitat using woody habitat structures and improving lateral connectivity to the floodplain and side channels. This will result in improved survival for all freshwater life stages. The project will provide increased foraging and rearing (summer and winter) opportunities for juvenile salmonids near the Patterson-Big Springs production reaches for Chinook and steelhead. The concept design directly addresses these life stages by developing instream habitat and floodplain/side channel diversity.