Geology topics

Caitlin Louise Stockwell

Publications and source records attributed to Caitlin Louise Stockwell.

2 recordsLinked to original sources

USGS2026

Evaluating reservoir passage and survival of juvenile Chinook Salmon to support reintroduction upstream of Shasta Dam, California

Objective Juvenile Chinook Salmon Oncorhynchus tshawytscha that are released upstream of Shasta Reservoir migrate more than 35 km to reach Shasta Dam, although survival through this system is poorly understood. We conducted a reservoir-scale acoustic telemetry study to quantify downstream movement and survival under seasonally variable environmental conditions to inform decisions about juvenile collection strategies for Chinook Salmon reintroduction above Shasta Dam. Methods A total of 656 hatchery-origin juvenile Chinook Salmon were acoustic-tagged, released near the mouth of the McCloud River, and monitored in Shasta Reservoir and the Sacramento River from September 2024 through March 2025 using an array of telemetry receivers. Results Most tagged fish failed to move downstream through the McCloud River Arm of Shasta Reservoir and arrive at Shasta Dam. Survival probabilities were estimated at 0.268 to the downstream end of the McCloud River Arm and 0.119 to Shasta Dam. For fish that did reach the dam, elapsed time from release to arrival was 66.4 d, and fish typically arrived and departed during daylight hours. Nine tagged juveniles were detected downstream of the dam, and three were later detected more than 500 km downstream. Conclusions The consistently low survival and restricted downstream movement provide important information indicating that downstream collection of juvenile Chinook Salmon should be focused in the lower McCloud River and the upper portion of the McCloud River Arm of Shasta Reservoir rather than at Shasta Dam.

California↗

USGS2025

Evaluation of juvenile salmon behavior to inform downstream fish passage development at a high head dam

F ish passage development is a priority at Tieton Dam, on the Tieton River in Washington state, because passage options were not included when the dam was constructed nearly 100 years ago. To inform downstream passage design, we conducted a study to evaluate migration and near-dam behavior of juvenile salmon. The primary goal of the study was to determine how fish approached the dam and to identify areas where they congregated. In its current configuration, water is passed through a deep intake located approximately 548 m upstream of the dam, so there was interest in determining if juvenile salmon spent more time near the intake or at the dam. We found that tagged fish primarily entered the dam forebay offshore and arrived at the dam near the spillway on the left bank of the reservoir. Tagged fish had extended residence times in the forebay and moved repeatedly between the intake and the dam. Using thermal profile data, we inferred that juvenile salmon likely occupied the upper 5 m of the water column during May and June before moving to deeper portions of the water column (10–27 m) during July–September when the reservoir became thermally stratified. We found that a small percentage of tagged fish passed the dam when the reservoir was rapidly drawn down during August–October, but additional research may be needed to fully assess entrainment risk through the intake. These findings suggest that downstream fish passage could be developed at Tieton Dam with a high probability of success, given that most fish survived reservoir passage and spent considerable time near the dam where they would be available to discover and utilize new passage routes.

Washington↗