Matthew W. Johnston
Heather M. Bragg
2016
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<p>An analysis of total-dissolved-gas (TDG) and water-temperature data collected at eight fixed monitoring stations on the lower Columbia River in Oregon and Washington in water year 2015 indicated the following:</p>
<ul>
<li>All but 1 of the 85 TDG sensor laboratory checks that were performed after field deployment were within ±0.5-percent saturation of a primary standard.</li>
<li>After 3–4 weeks of deployment in the river, 79 of 89 TDG sensor field checks were within ±1.0-percent saturation of a secondary standard. Nine of the field checks greater than ±1.0-percent saturation occurred at the John Day Dam tailwater station and resulted in periods of deleted TDG data at the station.</li>
<li>All 90 barometric pressure field checks were within ±1 millimeter of mercury of a primary stand-ard, and all 90 water-temperature field checks were within ±0.2 degrees Celsius of a secondary standard.</li>
<li>TDG data were considered complete if received in real time and within 1-percent saturation of the expected value on the basis of calibration data, replicate quality-control measurements, and comparison to river conditions at adjacent stations. For the eight monitoring stations, data completeness ranged from 71.9 to 99.8 percent.</li>
<li>All quality-assurance values exceed the criteria established by the U.S. Army Corps of Engineers TDG monitoring plan. Criteria for data completeness (95-percent) were met at seven of the eight monitoring stations. Deleted data at the John Day tailwater station resulted in data completeness below criteria.</li>
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application/pdf
10.3133/ofr20151212
en
U.S. Geological Survey
Total dissolved gas and water temperature in the lower Columbia River, Oregon and Washington, water year 2015
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