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U.S. GEOLOGICAL SURVEY
Open-File Report 2007-1408

Total Dissolved Gas and Water Temperature in the Lower Columbia River, Oregon and Washington, 2007: Quality-Assurance Data and Comparison to Water-Quality Standards

Prepared in cooperation with the U.S. Army Corps of Engineers

By Dwight Q. Tanner, Heather M. Bragg, and Matthew W. Johnston

A USGS scientist calibrates the water-quality station below John Day Dam, December 27, 2006.

Significant Findings

When water is released through the spillways of dams, air is entrained in the water, increasing the downstream concentration of dissolved gases. Excess dissolved-gas concentrations can have adverse effects on freshwater aquatic life. The U.S. Geological Survey (USGS), in cooperation with the U.S. Army Corps of Engineers, collected dissolved-gas and water-temperature data at eight sites on the lower Columbia River in 2007. Significant findings from the data include:

• From early July to mid-September 2007, water temperatures were above 20 °C (degrees Celsius) at each of the eight lower Columbia River sites. According to the Oregon temperature standard, the 7-day average maximum temperature of the lower Columbia River should not exceed 20 °C; Washington regulations state that the 1-day maximum should not exceed 20 °C due to human activities.
• Most in-situ field checks of total-dissolved-gas sensors with a secondary standard were within ± (plus or minus) 1% saturation after 3 to 4 weeks of deployment in the river. All of the field checks of barometric pressure were within ±2.5 millimeter of mercury of a secondary standard, and water-temperature field checks were all within ±0.2 °C.
• For the eight monitoring sites in water year 2007, an average of 99.5% of the total-dissolved-gas data were received in real time by the USGS satellite downlink and were within 1% saturation of the expected value on the basis of calibration data, replicate quality-control measurements in the river, and comparison to ambient river conditions at adjacent sites. Data received from the sites ranged from 97.9% to 100.0% complete.

Contents

Significant Findings
Introduction
Purpose and Scope
Methods of Data Collection
Summary of Total-Dissolved-Gas Data Completeness and Quality
Quality-Assurance Data
Effects of Spill on Total Dissolved Gas
Comparison of Total Dissolved Gas and Temperature to Standards
References Cited

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Download the report (PDF, 1.7 MB)

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Send questions or comments about this report to the author, D.Q. Tanner, (503)251-3289.

For more information about USGS activities in Oregon, visit the USGS USGS Oregon Water Science Center home page.