Fact Sheets, Studies & Resources
Check out the fact sheets and studies related to our work.
Good science is at the heart of our fisheries and water quality program.
Our biologists and technicians work with partner organizations and expert consultants to gather and analyze the data needed to make the best management decisions possible in support of healthy, wild salmon, steelhead and other species in the Deschutes Basin above and below our project.
Pelton Round Butte project resources
We’re making progress toward the shared long-term goal of a sustainable ecosystem and a healthy native salmon and steelhead population.
- Pelton Round Butte Hydroelectric Project Overview
Learn about how PGE is working to meet our commitment to a healthy river and healthy fish.
- Plain Facts on the Deschutes
CTWS and PGE responses to some common questions about the Deschutes river.
- Restoring Fish Passage on the Deschutes
- Restoring Fish Runs to the Upper Deschutes Basin
Certifications and awards
PGE and the CTWS continuously monitor water quality as part of our responsibility to the environment. We work closely with regulators for the State of Oregon and the Tribes to understand and mitigate the impact of our project while helping improve conditions for fish and other aquatic life.
For more detailed information, visit our Deschutes Water Quality page.
Water quality resources
The following studies evaluate all aspects of the reintroduction program – from rearing in the streams to downstream smolt migration, survival through the reservoir and in the lower Deschutes river and finally their return as adults.
These studies are conducted by fisheries biologists with PGE and the Tribes.
Adult migration, survival and spawning
As adult Chinook, sockeye and summer steelhead return to the Pelton Fish Trap, located below the Re-Regulating Dam, we identify reintroduction fish – fish that reared in upstream tributaries – by a jaw clip we gave them as smolts when they were captured at the SWW.
These fish are transported above the project and released into Lake Billy Chinook to spawn in the upper tributaries.
A sub-sample of adults receive a radio tag, allowing biologists to track their movements through Lake Billy Chinook and their chosen tributary. Each radio tag emits a unique signal we can detect using antennas.
In these annual reports you will find adult return numbers, timing, movement data and spawning locations.
Juvenile rearing, densities and habitat
During the late summer to early fall, researchers use mark-recapture electrofishing to sample the juvenile redband/steelhead trout population and estimate the population sizes in Whychus, McKay and Ochoco creeks.
Juvenile Chinook salmon are also captured. Electrofishing results are also reported in the PGE Native Fish Monitoring Report.
In the Metolius River, Lake Creek and Whychus Creek, we conduct snorkeling surveys in spring, summer and fall to estimate spring Chinook parr densities and measure growth throughout the year.
We operate downstream migrant traps, called rotary screw traps, in the tributaries that feed Lake Billy Chinook, including the Metolius and Crooked rivers, Ochoco, McKay and Whychus creeks.
These traps capture downstream migrating salmon and steelhead smolts. By releasing captured fish above the traps we can calculate capture efficiencies for the population, allowing us to estimate the number of migrating smolts.
PIT tags help us collect additional information about smolt behavior. In these reports you’ll find information on tributary smolt population estimates, travel times through the reservoir, growth, percentage of smolts captured at the SWW, and survival to the mouth of the Deschutes River and Bonneville Dam.
Reservoir survival, predation, fishery and disease
Several of our studies help us evaluate factors that may affect the survival of salmon and steelhead smolts migrating into and through Lake Billy Chinook.
Our reservoir survival studies use radio and PIT-tags to estimate survival (based on collection efficiency) from tributary smolt traps and release locations to the Selective Water Withdrawal (SWW).
Studies looking at Lake Billy Chinook smallmouth bass (diet and populations) were conducted in 2009 and 2014, and a bull trout diet study was conducted 2011-2013. Both of these studies help assess the impact of predation on salmon and steelhead smolts.
A recurring creel survey also looks at the number of salmon and steelhead smolts captured by anglers.
Lastly, Oregon Department of Fish and Wildlife pathologists examine fish captured throughout the Deschutes Basin, including at the SWW, to identify health issues.
Upper basin studies
A key component of our work on the Deschutes is the reintroduction of salmon and steelhead into the upper basin.
We use research conducted by our partners into the condition of other fish species in the upper basin to better understand the entire system and the impact of our project.
Deschutes River sockeye development project
Study by CTWS
Using seine nets, researchers catch thousands of kokanee each summer in the Metolius Arm of Lake Billy Chinook. Captured fish are tagged with a 2” fluorescent plastic tag and released.
Kokanee then continue upstream into the Metolius River to spawn, where crews survey the river and record the number of fish observed with and without tags. The information is used to estimate how many kokanee left Lake Billy Chinook to spawn.
During the spring, the Tribes operate a rotary screw trap in Lake Creek below the outlet of Suttle Lake to capture and estimate how many kokanee are leaving the lake. Some of the fish are implanted with PIT-tags so their movement downstream can be tracked.
In the summer and winter, CTWS researchers survey 41 transects in Lake Billy Chinook using boat mounted hydroacoustics (a high powered fish finder) to estimate the number of fish by size class.
Modified flow regime and Crooked River fish below Bowman Dam
Study by Oregon Department of Fish and Wildlife
ODFW crews use drift-boat-mounted electrofishing gear to periodically sample Crooked River redband trout and mountain whitefish populations between Big Bend and Cobble Rock campgrounds.
Captured fish are weighed, measured and marked before release. The reach is sampled again the following day and the numbers of marked and unmarked fish are recorded.
This information allows a population estimate to be calculated, expressed as the number of fish per mile.
In this report, population estimates for redband trout from 2006 to 2016 are compared to the Bowman Dam discharge to better understand how dam operations may impact fish populations in the Crooked.
The report also includes redband and whitefish population estimates for 1989, 1993 to 1995, 2001, 2003 and 2006 to 2016.
Crooked River Redband Trout
Study by Cramer Fish Sciences
Researchers conducted backpack and drift boat electrofishing to collect redband trout in the Crooked River below Bowman Dam.
Fin-clips were taken from some larger fish for genetic analysis to determine if they were native Crooked redband or steelhead from Round Butte Hatchery.
In this report you will find information on the life history of Crooked River redband, estimated number of fish in the Crooked River below Bowman Dam, the habitat conditions and results of genetic analysis.
Lower Deschutes River fish studies
One of the goals of restoring a more natural temperature regime downstream of the Pelton Round Butte project was to improve conditions for fall Chinook and redband trout.
ODFW and CTWS have been closely monitoring these populations in the lower Deschutes River.
Growth, condition, and age structure of redband trout in the lower Deschutes River
Study by Oregon Department of Fish and Wildlife
ODFW personnel sample the redband trout population in four reaches in the lower Deschutes River between Trout Creek (river mile 87) and Beaver Tail Boat Ramp (river mile 31).
Fish are captured using a drift-boat-mounted electrofishing unit. Sampling occurs within reaches historically studied by ODFW to compare changes over time, specifically changes after the Selective Water Withdrawal system became operational.
Data on fish survival, condition, age, length, weight, sex and stomach contents is summarized in these reports.
Deschutes River fall Chinook monitoring and research
Study by CTWS
To monitor the wild fall Chinook population in the lower Deschutes River, biologists using seine nets to capture and tag migrating smolts as they head toward the ocean.
Lengths and weights are recorded. PIT-tag information is used to track smolt migration down the Deschutes and Columbia Rivers, as well adult returns one to five years later.
To estimate adult returns, crews float the lower Deschutes between the Re-regulating Dam and Sherars Falls, counting post-spawn adults (carcass surveys) and the number of spawning redds.
Habitat, temperature, flows and more
Water temperature and flow data from U.S. Geological Survey monitoring stations
- Bowman Dam Hydroelectric Studies
Download studies conducted as part of an evaluation of hydroelectric power potential at Bowman Dam on Prineville Reservoir.
- Relicensing Reports – StreamNet Regional Library
- Table of reports submitted to the Federal Energy Regulatory Commission (FERC)