Potlatch River Steelhead Monitoring and Evaluation

The Potlatch River Steelhead Monitoring and Evaluation project is a long-term monitoring effort to assess the effectiveness of habitat restoration efforts within the Potlatch River, Idaho. The project is conducted annually by IDFG personnel and provides data on wild steelhead (Oncorhynchus mykiss) production and productivity in index watersheds, a monitoring component for restoration projects, and an effective method for identifying additional restoration projects. IDFG operated weirs, instream PIT-tag detection systems, and rotary screw traps to monitor the annual abundance and life history characteristics of steelhead. Habitat and electrofishing surveys were also conducted to monitor rearing habitat conditions and juvenile steelhead production metrics in treatment and control areas. During the reporting period (2018-2021), IDFG documented several important findings: 1) positive trends in emigrant age structure, growth, and survival in the East Fork Potlatch River during recent treatment years, 2) increases in juvenile steelhead growth and survival in response to a flow supplementation project, and 3) upstream expansion in adult steelhead spawning distribution following a culvert modification project. Once restoration goals are achieved, IDFG estimates a 10 year post-treatment monitoring period will be needed to gather data through multiple steelhead life cycles to detect changes in steelhead productivity related to restoration efforts.

This project continues IDFG’s umbrella watershed monitoring program for the Potlatch River, which is an Intensively Monitored Watershed. The framework of the Potlatch River Steelhead Monitoring and Evaluation Project (PRSME) provides: 1) data on Potlatch River steelhead production and productivity on multiple scales (index drainages to individual stream reaches), 2) a monitoring component for the numerous habitat restoration projects currently being implemented, 3) an effective and efficient method for identifying additional high priority and high reward habitat restoration projects in the Potlatch River basin, and 4) valuable monitoring in Lower Mainstem Clearwater River population, Clearwater Major Population Group (MPG). The PRSME is intended to provide long-term effectiveness monitoring for restoration actions implemented as directed by the Potlatch River Watershed Management Plan.


Project objectives:

1. Assess steelhead production and productivity within the Potlatch River basin

a) Determine juvenile steelhead outmigration timing and emigration rate

b) Estimate adult steelhead escapement

c) Establish juvenile recruits/female spawner productivity relationships


2. Provide habitat effectiveness monitoring for restoration projects within the Potlatch River basin

a) Monitor juvenile steelhead production (density, survival and growth) in treatment and control tributaries in focus watersheds under a before-after-control-impact (BACI) framework.

b) Monitor changes in habitat variables associated with habitat restoration actions in each basin