Skip to main content
U.S. flag

An official website of the United States government

Alexandra Etheridge

Alex Etheridge is the Associate Director for Studies in the USGS Oregon Water Science Center


Hydrologic Technician, Colorado River Decree Accounting Project, Arizona Water Science Center, 2006-2008 

Hydrologic Technician, Boise Field Office, Idaho Water Science Center, 2008-2010

Studies Hydrologist, Idaho Water Science Center, 2010-2016

Water-Quality Specialist, Data Program, California Water Science Center, 2016 - 2021

Technical Water-Quality Specialist: Provide technical support for collection, processing, management and quality assurance of discrete and time-series water-quality data. Wrote an R script to determine water temperature frequency of exceedance for various coldwater habitat and salmonid spawning temperature criteria. Wrote IDWSC protocols for collecting and computing time-series water temperature data. Designed and implemented IDWSC archival structure for paperless water-quality records computation. Maintained database and calibration logs for IDWSC multi-parameter water-quality sondes. Designed, tested, and installed an air-purge system to minimize sediment fouling issues for continuous monitor, resulting in a $10,000 reduction in annual O&M costs. Shadowed USGS review team during 2015 triennial water-quality review.

Water-Quality Modeling: Utilized streamflow variability as a predictor variable in LOADEST models to account for hysteresis in transport of sediment and sediment-associated constituents in the headwaters of the Salmon River in Idaho and in the Kootenai River in Idaho. Developed surrogate regression models to estimate continuous dissolved arsenic and antimony concentrations in the East Fork of the South Fork of the Salmon River, and total mercury concentrations in Sugar Creek. Published surrogate model estimates on the National Real-Time Water-Quality website (NRTWQ) with a report in late 2015.

Developed surrogate regression models for total phosphorus, total nitrogen, and suspended sediment at the streamflow gage in the Mason Creek tributary to the lower Boise River. Summarized water-quality modeling results in a report.

Developed surrogate regression models and used published results to motivate re-instatement of the continuous monitor near the mouth of the Boise River and currently provide continuous estimates of total phosphorus and suspended sediment concentrations and loads for the Idaho Real-Time Water Quality (NRTWQ) application.  Used Weighted Regression on Time Discharge and Season (WRTDS) to estimate seasonal trends in total phosphorus concentrations and loads near the mouth of the Boise River. Compared WRTDS results to surrogate model estimates during winter storm events.

Developed three mass-balance models for total phosphorus in the lower Boise River and summarized findings in a report. Mobilized and assisted three field crews during three synoptic sampling events at more than 40 sites spread over 64 river miles. Cooperators used mass-balance models to finalize a total

Education and Certifications

  • B.S. Geology, Western Washington University, 1998

  • M.A. Writing and Publishing, Emerson College, 2000

Science and Products