The Royes Dam project is part of a larger effort called the Free Willow, Lower Willow Creek Fish Passage project and is intended to improve passage for adult Chinook Salmon and steelhead. The project will allow adult Chinook salmon passage into the Willow basin for the first time in over 70 years. In addition, this project will allow juvenile salmonids both upstream and downstream passage for large portions of the year while stream temperatures allow.

The construction of the Royes and Huber irrigation dams in the 1950's created physical obstructions for salmonid migration into the Willow Creek Watershed. Anecdotal information from early fishing reports indicate that Chinook were abundant in the watershed. Passage of adult salmonids upstream and juvenile salmonids downstream is potentially completely blocked as early as March of each year. Although some adult steelhead pass through the dam prior to the installation of flashboards, Chinook salmon adults moving into Willow Creek in the early summer months are completely blocked from upstream migration. Chinook have not been documented in the Willow Creek basin since the construction of the Huber and Royes dams.

Fish passage at these lower Willow Creek irrigation diversions has been a high priority identified as a significant limiting factor for the recovery of endangered Chinook and steelhead populations in the Upper Grande Ronde basin. The District has installed a concrete fishway at the lower Huber Dam during the summer of 2022. The Royes Dam is a flashboard weir that generally functions from April to October each year. When the flashboards are in the structure, an 8- to 10-foot barrier is created without a jump pool. During the season of operation this structure eliminates all salmonid migration. The District has secured the support of the 5 irrigators relying on the backwater from the Royes diversion dam to construct a rock ramp to back water up and eliminating the need for the dam structure. District staff and project partners have worked on fish passage at these sites for the past 20 years. For the first time in that span, the water users are on board to make fish passage a reality.

Fish passage design has focused on collecting data to inform the creation of individual pump sites at four different locations above the Royes Dam and eliminate the need for flashboard installation. The primary path of investigation is a roughened channel alternative. Survey data was collected at each site and hydraulic analysis performed to assure channel modifications will not lead to increased flooding and channel instability. Funding provided by ODFW allowed the District to complete project design to the 80% level. Funding deliverables for this Technical Assistance grant project will include final designs and all required permitting.