New gages help characterize extent of spring Chinook salmon habitat in the Willamette Basin
Learn about our new streamgages in the Williamette River Basin.
The U.S. Geological Survey (USGS) is expanding the streamgaging network in the Willamette River Basin of northwestern Oregon by adding sites in remote, unregulated, and ungaged streams in the Clackamas, Santiam, Molalla, McKenzie, and Middle Fork Willamette River basins. The new sites are in stream reaches in the Cascade Range that are used by spring Chinook salmon (and in some cases, winter steelhead and bull trout) throughout the year. Experts from USGS and partner agencies carefully chose site locations to coincide approximately with the upstream extent of spawning by spring Chinook salmon.
As of September 1, 2024, USGS has installed 14 new gages in unregulated spawning reaches. Monitoring includes:
- Continuous water temperature and water level data. Data is available online. Some sites transmit data in real-time, approximately every hour, and for others, the data is downloaded during site visits.
- Streamflow. During site visits, scientists measure streamflow to help document the range of flow pertinent to habitat conditions.
- Air temperature. Monitored at nine locations, this data can be used to better identify which reaches could be susceptible to warming.
- Year-round photo documentation. Eight of the gages have specially designed, time-lapse cameras that allow the public to see year-round streamflow and habitat conditions near the gages. In some cases, cameras have captured fish and wildlife activity. The cameras are part of the USGS Flow Photo Explorer program.
Data from the new gages will provide a basis for understanding current and future habitat conditions and how some of these reaches may respond to extreme events like heat waves and droughts. In particular, the year-round water-level and temperature data will be used to describe habitat implications for spring Chinook salmon during the following conditions:
- Summer months when adult salmon are holding in rivers prior to spawning and when stressful warm water temperatures can contribute to pre-spawning mortality.
- Fall conditions when adult salmon spawn and eggs begin incubation. Stressful warm water conditions can be harmful to both adults and eggs.
- Winter months when embryos are incubating. During this period, direct mortality can occur due to high flows (causing redd scour) and heavy sedimentation (redd suffocation). Altered temperature regimes can affect emergence timing and synchronization with important biological windows (such as food availability and seasonal growth).
- Spring, summer, and fall months when juvenile salmon are rearing and migrating downstream and when stressful warm temperatures can affect behavior, health, disease, and predation potential by non-native fish.
This project is funded by USGS Water Mission Area’s Next Generation Water Observing Systems (NGWOS) to support the Willamette River Basin Integrated Water Science program.
