Alexandra Etheridge



B.S. Geology, Western Washington University, 1998

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



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 - present 

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 on NRTWQ.  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 phosphorus TMDL and continue to use mass-balance models to finalize water-quality trading location ratios and evaluate trading credit life.

Obtained cooperator agreement to collect automated samples for total phosphorus in the lower Boise River over the next 10 years during a period of relatively rapid watershed-scale change. Wastewater treatment plants and stormwater permittees will begin meeting new permit requirements and water-quality trading projects on agricultural lands have been incentivized with a total phosphorus TMDL. Water-quality data will be used to compare LOADEST, WRTDS, and surrogate model results for total phosphorus concentrations and loads. Water-quality models will also be used to detect trends, and results will be reported on a 5-year cycle.

Time-series Water-Quality Data Workflows – Training and Curriculum Development: Developing training materials and conducting ongoing performance testing of Aquarius time-series data management software from Aquatic Informatics due for USGS roll-out in 2016. Developed curriculum and co-taught class to the Iraqi Ministry of Water Resources and the Kurdish Regional Government on continuous water-quality data collection and processing (2010). Assist (since 2012) with teaching the USGS Continuous Water-Quality Monitors Records Computation (QW2298) class.

Public Outreach and Science Communication: Present science information to diverse cooperator groups and in educational outreach settings. Present findings at local and national conferences and in cooperator meetings. Listen for, understand, and formulate relevant research objectives to inform water resource management and policy decisions.


Holloway, J.M., Pribil, M.J., McCleskey, R.B., Etheridge, A.B., Krabbenhoft, D.P., and Aiken, G.R., 2017, Mobilization of Mercury and Arsenic from a Carbonate-hosted Ore Deposit, Central Idaho, U.S.A.: Procedia Earth and Planetary Science, 17, p. 610-613, doi:10.1016/j.proeps.2016.12.163.

Etheridge, A.B., 2015, Occurrence and transport of selected constituents in streams near the Stibnite mining area, central Idaho, 2012–14: U.S. Geological Survey Scientific Investigations Report 2015–5166, 47 p. [Link]

Wood, M.S., Fosness, R.L., and Etheridge, A.B., 2015, Sediment transport and evaluation of sediment surrogate ratings in the Kootenai River near Bonners Ferry, Idaho, water years 2011–14: U.S. Geological Survey Scientific Investigations Report 2015–5169, 48 p. [Link]

Etheridge, A.B., MacCoy, D.E., and Weakland, R.J., 2014, Water-quality and biological conditions in selected tributaries of the lower Boise River, southwestern Idaho, water years 2009-12: U.S. Geological Survey Scientific Investigations Report 2014-5132, 58 p. [Link]

Williams, M.L., and Etheridge, A.B., 2013, An evaluation of seepage gains and losses in Indian Creek Reservoir, Ada County, Idaho, April 2010–November 2011: U.S. Geological Survey Scientific Investigations Report 2013-5047, 26 p. [Link]

Etheridge, A.B., 2013, Evaluation of total phosphorus mass balance in the lower Boise River, southwestern Idaho: U.S. Geological Survey Scientific Investigations Report 2013–5220, 70 p. [Link]

Wood, M.S., and Etheridge, A.B., 2011, Water-quality conditions near the confluence of the Snake and Boise Rivers, Canyon County, Idaho: U.S. Geological Survey Scientific Investigations Report 2011–5217, 70 p. [Link]