As identified in Catherine Creek Atlas CC 2C at this location will improve irrigation water use efficiency, (b) decrease the negative hydrologic effects associated with Elmer Dam in its current state, (c) improve fish passage for all native fishes at all water levels and provide unimpeded passage to approximately 40 of miles of critical spawning and/or rearing habitat for ESA-listed salmon, (d) increase aquatic habitat quality, and (e) increase climate change resiliency.

The project area is the migration corridor for all native fish species in the Catherine Creek subbasin, including State Sensitive Snake River Basin Redband Trout (Oncorhynchus mykiss gairdneri) and Pacific Lamprey (Entosphenus tridentatus), as well as designated critical habitat for three federal Endangered Species Act (ESA)-listed species: Snake River (SR) Spring Chinook Salmon (Oncorhynchus tshawytscha), SR Summer Steelhead Trout (Oncorhynchus mykiss), and Bull Trout (Salvelinus confluentus) in the Mid-Columbia Recovery Unit.

The proposed actions in this project are significant to support the recovery and conservation of these State Sensitive and ESA-listed fish species, they all must pass through the project reach to get to their spawning and rearing habitat and for smolts to emigrate back to the ocean.

ESA-listed SR Summer Steelhead use lower Catherine Creek for migration and rearing. Most adult steelhead enter the lower Grande Ronde River from September through March, with some entering as early as July. Most smolt emigration occurs from April through June. Limiting factors for Catherine Creek Spring Chinook salmon are likely applicable to Summer Steelhead found in Catherine Creek, including habitat quantity and quality, sediment conditions, water quality, and water quantity (ESA Recovery Plan: Snake River Spring/Summer Chinook Salmon and Snake River Basin Steelhead, NMFS, 2017).

Catherine Creek supports both life history forms of Bull Trout. The Upper Grande Ronde Bull Trout Threats Assessment (USFWS, 2022) indicates the primary threat to be connectivity impairment from temperature barriers and low flows. Migrating Bull Trout return to spawning tributaries from the end of June into October, with spawning occurring in the headwaters between mid-September and early November. The project reach is used for migration, foraging and overwintering (FMO) habitat.

Redband Trout adult migration occurs October through May, with spawning April through June and rearing has been observed in Catherine Creek year-round (sub-adult and juvenile combined). The ODFW Conservation Strategy (2016) identifies water quality, alterations of hydrology and watershed function, passage, and riparian condition as limiting factors.

Pacific Lamprey spawn March through August and juvenile outmigration occurs autumn through spring (ODFW Coastal, Columbia, and Snake Conservation Plan for Lampreys in Oregon, 2020). The key limiting factors identified are “artificial obstructions to habitat, reduced flows, water quality, stream and floodplain degradation, and predation by other species.” Construction of the Elmer Dam Project will provide unimpeded passage for Pacific Lamprey. The current fishway does not provide adequate passage for lamprey species.

The proposed project is in Union County within the Catherine Creek River Basin, near the confluence of the Grande Ronde River. The project goals are to (a) improve irrigation water use efficiency, (b) decrease the negative hydrologic effects associated with Elmer Dam in its current state, (c) improve fish passage for all native fishes at all water levels and provide unimpeded passage to approximately 40 of miles of critical spawning and/or rearing habitat for ESA-listed salmon, (d) increase aquatic habitat quality, and (e) increase climate change resiliency. The fishway and dam improvements coupled with on-farm improvements to off-channel reservoirs and intakes will result in unimpeded fish passage and more natural hydrologic scenarios throughout this migration corridor for all native fishes. Match funding has been secured for the fishway and dam improvements, we are seeking OWRD funds for the on-farm improvements to the off-channel reservoirs and intakes (not described in this SOW).

NRCS is supporting the Project with matching funds to convert the wheel line irrigation systems to center-pivots. This will increase the productivity and efficiency of the landowner’s field crop farming operations while conserving water.  This task is not described in this SOW.  

Project elements include: (1) New Vertical Slot Fishway with multiple entrances and exits to accommodate volitional passage for all species and life stages throughout a wider range of flow scenarios; (2) Elmer Dam Improvements adding an overshot gate to the dam to accommodate increased hydraulic capacity during spring high flow events; (3) On-Farm Improvements involving installation of two center-pivots, connecting the three off-channel reservoirs together through piping, and moving the two in-channel pumps to off-channel wet wells, allowing them to operate as one large system. Reducing the number of intakes from Catherine Creek into the reservoirs from three to one and providing NOAA-Fisheries and ODFW approved fish screens will improve screening operations, reduce fish impingement, and reduce the maintenance required to fill the reservoirs during high flows; and (4) Installing PIT antenna arrays to the new fishway and dam structure allowing project partners to track PIT-tagged fish through the migration corridor leading to better species escapement data.