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

Total Dissolved Gas and Water Temperature in the 

Lower Columbia River, Oregon and Washington, 2005: 

Quality-Assurance Data and Comparison to WaterQuality Standards 

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

Data Series 148 

U.S. Department of the Interior 

U.S. Geological Survey 
U.S. Department of the Interior 

Gale A. Norton, Secretary 

U.S. Geological Survey 

P. Patrick Leahy, Acting Director 

U.S. Geological Survey, Reston, Virginia 2005 

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Suggested citation: 

Tanner, D.Q., Bragg, H.M., and Johnston, M.W., 2005, Total dissolved gas and water temperature in the 

lower Columbia River, Oregon and Washington, 2005—Quality-assurance data and comparison to waterquality standards: U.S. Geological Survey Data Series 148, 27 p. 

The use of trade, product, or firm names is for descriptive purposes only and does not imply 

endorsement by the U.S. Government. 

Although this report is in the public domain, permission must be secured from the individual 

copyright owners to reproduce any copyrighted material contained within this report. 

ii
Contents 

Significant Findings ........................................................................................................................................................... 1

Introduction......................................................................................................................................................................... 2

Background..................................................................................................................................................................... 3

Purpose and Scope........................................................................................................................................................ 3

Methods of Data Collection.............................................................................................................................................. 4

Summary of Total-Dissolved-Gas Data Completeness and Quality.......................................................................... 5

Quality-Assurance Data.................................................................................................................................................... 9

Effects of Spill on Total Dissolved Gas......................................................................................................................... 12

Comparison of Total Dissolved Gas and Temperature to Standards ..................................................................... 21

References Cited.............................................................................................................................................................. 26

Figures 

Figure 1. Location of total-dissolved-gas fixed stations, lower Columbia River, Oregon and Washington, 

water year 2005. ................................................................................................................................................................. 2

Figure 2. Accuracy of total-dissolved-gas sensors after 2 to 3 weeks of field deployment .............................. 10

Figure 3. Difference between the secondary standard and the field barometers after 2 to 3 weeks of field 

deployment........................................................................................................................................................................ 11

Figure 4. Difference between the secondary standard and the field temperature instruments after 2 to 3 

weeks of field deployment.............................................................................................................................................. 11

Figure 5. Difference between the secondary standard and the field total-dissolved-gas instruments after 

2 to 3 weeks of field deployment................................................................................................................................... 12

Figure 6. Total dissolved gas saturation downstream from John Day Dam and spill from John Day Dam, 

April 5 to September 5, 2005........................................................................................................................................... 14

Figure 7. Total dissolved gas saturation downstream from The Dalles Dam and spill from The Dalles Dam, 

April 5 to September 5, 2005........................................................................................................................................... 15

Figure 8. Total dissolved gas saturation downstream from Bonneville Dam at Warrendale and spill from 

Bonneville Dam, April 5 to September 5, 2005.. .......................................................................................................... 16

Figure 9. Total dissolved gas saturation downstream from Bonneville Dam at Cascade Island and spill 

from Bonneville Dam, April 5 to September 5, 2005................................................................................................... 17

Figure 11. Total dissolved gas saturation upstream from The Dalles Dam, April 5 to September 5, 2005....... 19

Figure 12. Total dissolved gas saturation upstream from Bonneville Dam, April 5 to September 5, 2005....... 20

Figure 13. Total dissolved gas saturation at Camas, April 5 to September 5, 2005.............................................. 20

Figure 14. Distributions of hourly total-dissolved-gas data and exceedances of Oregon and Washington 

water-quality variances, April 10, 2005, to August 31, 2005...................................................................................... 22

Figure 15. Water temperature upstream and downstream from John Day Dam, summer 2005 ....................... 23

Figure 16. Water temperature upstream and downstream from The Dalles Dam, summer 2005 ..................... 23

Figure 17. Water temperature upstream and downstream from Bonneville Dam, summer 2005 ..................... 24

iii
Figure 18. Water temperature at Cascade Island, summer 2005 ............................................................................ 24

Figure 19. Water temperature at John Day navigation lock and Warrendale, summer 2005............................ 25

Figure 20. Water temperature at Camas, summer 2005............................................................................................ 26

Tables 

Table 1. Total-dissolved-gas fixed stations, lower Columbia River, Oregon and Washington, water year 

2005....................................................................................................................................................................................... 4

Table 2. Total-dissolved-gas data completeness and quality, lower Columbia River, Oregon and 

Washington, WY-2005 ....................................................................................................................................................... 6

Table 3. Missing or deleted data, water year 2005...................................................................................................... 7

Table 4. Exceedances of States of Oregon and Washington water-quality variances for total dissolved 

gas, lower Columbia River, Oregon and Washington, water year 2005................................................................. 21

Conversion Factors 

Multiply By To obtain 

inch (in.) 2.54 centimeter (cm) 

mile (mi) 1.609 kilometer (km) 

square mile (mi2) 2.590 square kilometer (km2) 

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s) 

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows: 

°F=(1.8×°C)+32 

Acknowledgments 

The authors acknowledge the aid and funding support of the U.S. Army Corps of Engineers. Our 

special thanks go to James L. Britton (USACE) for technical and logistical support of the project. The 

authors also thank Amy Brooks (USGS) for preparing summaries and analyses of data. 

iv
Total Dissolved Gas and Water Temperature in the 

Lower Columbia River, Oregon and Washington, 2005: 

Quality-Assurance Data and Comparison to WaterQuality Standards 

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

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 2005. Significant findings from the data include: 

• Variances to the Oregon and Washington water-quality standards for total dissolved gas were exceeded at five of the monitoring sites: Camas (11 days), John Day tailwater (3 days), The Dalles 

forebay (3 days), Bonneville forebay (3 days), and John Day navigation lock (1 day). 

• From mid-July to early September, 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 field checks of total-dissolved-gas sensors with a secondary standard were within ± (plus or 

minus) 1% saturation. Most of the field checks of barometric pressure were within ±1 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 2005, an average of 98.2% 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, based on calibration data, replicate quality-control measurements in the river, and 

comparison to ambient river conditions at adjacent sites. 

1
Introduction 

The U.S. Army Corps of Engineers (USACE) operates several dams in the Columbia River Basin (fig. 1), which encompasses 259,000 square miles of the Pacific Northwest. These dams are 

multipurpose structures that fill regional needs for flood control, navigation, irrigation, recreation, hydropower production, fish and wildlife habitat, water-quality maintenance, and municipal and industrial 

water supply. When water is released through the spillways of these dams (instead of being routed 

through the turbines to generate electricity), ambient air is entrained in the water, increasing the concentration of dissolved gases (known as total dissolved gas [TDG]) downstream from the spillways. TDG 

conditions above 110% saturation can cause gas-bubble trauma in fish and adversely affect other aquatic 

organisms (U.S. Environmental Protection Agency, 1986). 

Figure 1. Location of total-dissolved-gas fixed stations, lower Columbia River, Oregon and Washington, water 

year 2005. 

The USACE regulates spill and streamflow to minimize the production of excess TDG downstream from its dams, but there is also a goal of providing for fish passage with spilled water (rather than 

passage through the turbines). Consequently, the States of Oregon and Washington issue variances to the 

TDG water-quality standards during the spring and summer. In order to monitor compliance with these 

variances, the USACE oversees the collection of near real-time TDG and water-temperature data upstream and downstream from Columbia River Basin dams in a network of fixed-station monitors. Data 

from these sites are available within about 4 hours of current time. 

2
Background 

Near real-time TDG and water-temperature data are vital to the USACE for dam operation and 

for monitoring compliance with environmental regulations. The data are used by water managers to 

maintain water-quality conditions that facilitate fish passage and survival in the lower Columbia River. 

The USGS, in cooperation with the Portland District of the USACE, has collected TDG and related data 

in the lower Columbia River every year, beginning in 1996. Current and historical TDG and watertemperature data can be found on the USGS Oregon Water Science Center Website at 

http://oregon.usgs.gov/projs_dir/pn307.tdg/. Six reports that were published for water years 1996, 2000, 

2001, 2002, 2003, and 2004 contain TDG data, quality-assurance data, and descriptions of the methods 

of data collection (Tanner and others, 1996; Tanner and Johnston, 2001; Tanner and Bragg, 2001; Tanner and others, 2002; Tanner and others, 2003; and Tanner and others, 2004). 

To provide suitable data for managing and modeling TDG in the lower Columbia River, hourly 

data for 2005 were reviewed relative to laboratory and field measurements made during instrument calibrations and daily intersite comparisons. A small fraction of the TDG data were deleted because they 

were not of suitable quality. The hourly data were stored in a USGS data base (Automated Data Processing System—ADAPS) and in a USACE data base (http://www.nwd-wc.usace.army.mil/tmt/wcd/tdg/ 

months.html). The USACE data base also includes hourly discharge and spill data. 

Purpose and Scope 

The purpose of TDG monitoring in the lower Columbia River is to provide the USACE with (1) 

real-time data for managing streamflow and spill at its project dams, (2) reviewed TDG data to evaluate 

conditions relative to water-quality standards, and (3) data for modeling the effect of various management scenarios of streamflow and spill on TDG levels. 

This report describes the TDG data and related quality-assurance data from the lower Columbia 

River at eight sites, from the navigation lock of the John Day Dam (river mile [RM] 215.7) to Camas, 

Washington (RM 121.7), (fig. 1, table 1). Data for water year 2005 (October 1, 2004, to September 

30, 2005) include hourly measurements of TDG pressure, barometric pressure, water temperature, and 

probe depth. Six of the sites (John Day navigation lock, John Day tailwater, The Dalles forebay, The 

Dalles tailwater, Cascade Island, and Camas) were operated from February or March to September 

2005, which is the usual time of spill from the dams. Two sites (Bonneville forebay and Warrendale) 

were operated year-round. The site Columbia River at Cascade Island was installed in 2004 to assess 

TDG levels directly in the tailwater of Bonneville Dam, but the data from that site were not used for 

management purposes in water year 2005. 

3
Table 1. Total-dissolved-gas fixed stations, lower Columbia River, Oregon and Washington, water year 2005 

[Map reference number refers to figure 1; USACE, U.S. Army Corps of Engineers; Columbia River mile locations were determined 

from U.S. Geological Survey (USGS) 7.5-minute topographic maps; stations in this report are referenced by their abbreviated name or 

USACE site identifier, °, degree, ’, minute, ”, second] 

Map 

reference 

number 

USACE 

site 

identifier 

Columbia 

River 

mile 

USGS 

station number 

USGS station name 

(and abbreviated station name) Latitude Longitude 

Period of 

record 

1 JDY 215.7 454314120413701 Columbia River at John Day navigation lock, Washington (John Day 

navigation lock) 

45° 43’ 14” 120° 41’ 37” 03/22/05-

09/07/05 

2 JHAW 214.7 454249120423500 Columbia River, right bank, near 

Cliffs, Washington (John Day 

tailwater) 

45° 42’ 49” 120° 42’ 35” 03/22/05- 

08/29/05 

3 TDA 192.6 453712121071200 Columbia River at The Dalles Dam 

forebay, Washington (The Dalles 

forebay) 

45° 37’ 12” 121° 07’ 12” 03/28/05- 

09/08/05 

4 TDDO 188.9 14105700 Columbia River at The Dalles, 

Oregon (The Dalles tailwater) 

45° 36’ 27” 121° 10’ 20” 03/23/05- 

09/08/05 

5 BON 146.1 453845121562000 Columbia River at Bonneville Dam 

forebay, Washington (Bonneville 

forebay) 

45° 38’ 45” 121° 56’ 20” Yearround 

6 CCIW 145.9 453845121564001 Columbia River at Cascade Island, 

Washington (Cascade Island) 

45° 38’ 45” 121° 56’ 40” 02/25/05- 

09/09/05 

7 WRNO 140.4 453630122021400 Columbia River, left bank, near 

Dodson, Oregon (Warrendale) 

45° 36’ 30” 122° 02’ 14” Yearround 

8 CWMW 121.7 453439122223900 Columbia River, right bank, at 

Washougal, Washington (Camas) 

45° 34’ 39” 122° 22’ 39” 02/23/05- 

09/13/05 

Methods of Data Collection 

Methods of data collection for TDG, barometric pressure, and water temperature are described in 

detail in Tanner and Johnston (2001). A summary of these methods follows: Instrumentation at each 

fixed station consists of a Hydrolab water-quality probe, an electronic barometer, a power supply, and a 

Sutron Model 8200 data-collection platform (DCP). The instruments at each site are powered by a 12-

volt battery that is charged by a solar panel and/or a 120-volt alternating-current line. At the beginning 

of the monitoring season in February or March, a new TDG membrane is installed on each Hydrolab. 

Measurements (including probe depth) are made and logged every hour, and every 4 hours, the DCP 

transmits the most recent logged data to the Geostationary Operational Environmental Satellite (GOES) 

system (Jones and others, 1991). The data are automatically decoded and transferred to the USACE data 

base and to the USGS ADAPS data base. At one site, John Day tailwater, two TDG sensors have been 

installed on the same Hydrolab to ensure that data are reliably collected at this important site. 

The eight fixed-station monitors were calibrated every 2 weeks from March to September, 2005. 

The Warrendale and Bonneville forebay sites were the only sites in operation from October 2004 

4
through February 2005; during this time, they were calibrated every 3 weeks. The field calibration procedure was as follows: A Hydrolab (which was calibrated several days before the field trip and used as a 

secondary standard) was deployed alongside of the field Hydrolab for a period of up to 1 hour to obtain 

check measurements of TDG and water temperature prior to removing the field Hydrolab (which had 

been deployed for 2 or 3 weeks). The field Hydrolab was then replaced with one that had been calibrated 

recently at the laboratory and the secondary standard used again to check TDG and temperature measured by the newly deployed Hydrolab in the river. The electronic barometer at the fixed station was 

calibrated using a portable barometer that had been recently calibrated at the National Weather Service 

facility in northeast Portland. 

During each field calibration, the minimum compensation depth was calculated to determine 

whether the Hydrolab was positioned at an appropriate depth to measure TDG. This minimum compensation depth, which was calculated according to Colt (1984, page 104), is the depth above which 

degassing will occur due to decreased hydrostatic pressure. To measure TDG accurately, the Hydrolabs 

were positioned during each calibration visit at a depth below the calculated minimum compensation 

depth whenever possible. 

The Hydrolab that was brought from the field after 2 to 3 weeks of deployment was then calibrated in the laboratory. The integrity of the TDG membrane was checked, the membrane was air-dried, 

and the TDG sensor was calibrated at 0, 100, 200, and 300 mm Hg (millimeters of mercury) above atmospheric pressure to cover the expected range of TDG in the river (approximately 100, 113, 126, and 

139% saturation, respectively). 

Summary of Total-Dissolved-Gas Data Completeness and Quality 

A summary of USGS TDG data completeness and quality for water year 2005 is shown in table 

2. (The USACE satellite downlink was a parallel system, so the amount and quality of USACE data 

were similar). Data in table 2 were based on the total amount of hourly TDG data that could have been 

collected during the monitoring season. Any hour without TDG pressure data or barometric pressure 

data was counted as an hour of missing data for TDG in percent saturation, which is calculated as TDG 

pressure, in mm Hg, divided by the barometric pressure, in mm Hg, multiplied by 100. The fourth column in table 2 shows the percentage of data that was received in real time and passed quality-assurance 

checks. TDG data were considered to meet quality-assurance standards if they were within plus or minus 

1% saturation of the expected value, based on calibration data, replicate quality-control measurements in 

the river, and daily comparisons to ambient river conditions at adjacent sites. At each station, at least 

88.9% of the data were received in real time by the USGS downlink and met quality-control checks, 

with an overall average of 98.2% (table 2). 

5
Table 2. Total-dissolved-gas data completeness and quality, lower Columbia River, Oregon and 

Washington, WY-2005 

[Results are based on values in USGS ADAPS database; TDG, total dissolved gas] 

Abbreviated 

Station Name 

Planned 

Monitoring 

in Hours 

Number of 

Missing or Deleted Hourly 

Values 

Percentage of Real-Time 

TDG Data Passing Quality 

Assurance 

John Day navigation lock 4,054 8 99.8 

John Day tailwater 4,054 42 99.0 

The Dalles forebay 3,933 0 100.0 

The Dalles tailwater 4,052 1 100.0 

Bonneville forebay 8,760 20 99.8 

Cascade Island 4,694 519 88.9 

Warrendale 8,760 94 98.9 

Camas 4,738 21 99.6 

Average -- -- 98.2 

Table 3 is a chronological list of the major portions of data that were either missing from the database (for example, when data telemetry failed) or data that were later deleted from the database 

because they did not meet quality-assurance standards. Table 3 includes temperature and depth data, 

which were not considered in table 2, which included only TDG data. The Cascade Island site had the 

most missing or deleted data. From March 11, 2005, to March 24, 2005, the values measured by the 

TDG sensor were too low, based on quality-assurance measurements made during the field calibration 

on March 24. The incorrect values at Cascade Island were caused by a malfunctioning TDG sensor. Water circulation patterns at this site are complex, making it difficult to diagnose instrumentation problems. 

The malfunctioning instrument was taken out of service on March 24 and was not used for the remainder of the field season. A broken membrane at Cascade Island from August 31 to September 7 (a period 

of no spill) also caused loss of data at the site. 

6
Table 3. Missing or deleted data, water year 2005 

[Site abbreviations: WRNO, Warrendale; CCIW, Cascade Island; TDDO, The Dalles tailwater; BON, Bonneville forebay; JDY, 

John Day navigation lock; CWMW, Camas; JHAW, John Day tailwater. Date format: month/day/year. Parameter and unit abbreviations: TDG, total dissolved gas; --, no data; mm Hg, millimeters of mercury; BP, barometric pressure; WT, water 

temperature; °C, degrees Celsius] 

Date & Time Site Parameter Value Unit Reason / Notes 

1/17/05 07:00 WRNO TDG -- mm Hg Missed transmission 

through 

1/17/05 14:00 -- 

1/17/05 07:00 WRNO BP -- mm Hg Missed transmission 

through 

1/17/05 14:00 -- 

1/17/05 07:00 WRNO WT -- °C Missed transmission 

through 

1/17/05 14:00 -- °C 

1/17/05 07:00 WRNO Depth -- feet Missed transmission 

through 

1/17/05 14:00 -- feet 

3/11/05 13:00 CCIW TDG -- mm Hg Sensor drift caused low values 

through 

3/24/05 13:00 -- mm Hg 

4/7/05 10:00 TDDO TDG 836 mm Hg Slow calibration; forgot to delete at site 

4/7/05 14:00 BON BP 0 mm Hg Accidentally turned off logging during calibration 

through 

4/8/05 09:00 0 mm Hg 

4/7/05 17:00 CCIW TDG 881 mm Hg Slow calibration, left site before equilibrated 

through 

4/8/05 04:00 803 mm Hg 

4/20/05 11:00 JDY Depth 83.7 feet Bad sensor 

through 

5/3/05 10:00 83.7 feet 

4/19/05 13:00 CCIW TDG 746 mm Hg Calibration 

4/19/05 13:00 CCIW WT 18.1 °C Calibration 

4/19/05 13:00 CCIW Depth 13.5 feet Calibration 

7
Table 3. Missing or deleted data, water year 2005—continued

[Site abbreviations: WRNO, Warrendale; CCIW, Cascade Island; TDDO, The Dalles tailwater; BON, Bonneville forebay; JDY, 

John Day navigation lock; CWMW, Camas; JHAW, John Day tailwater. Date format: month/day/year. Parameter and unit abbreviations: TDG, total dissolved gas; --, no data; mm Hg, millimeters of mercury; BP, barometric pressure; WT, water 

temperature; °C, degrees Celsius] 

Date & Time Site Parameter Value Unit Reason / Notes 

5/9/05 04:00 JDY BP 733 mm Hg Low battery 

through 

5/9/05 11:00 621 mm Hg 

5/24/05 17:00 CWMW TDG -- mm Hg Missed transmission 

through 

5/25/05 08:00 -- mm Hg 

5/24/05 17:00 CWMW BP -- mm Hg Missed transmission 

through 

5/25/2005 08:00 -- mm Hg 

5/24/05 17:00 CWMW WT -- °C Missed transmission 

through 

5/25/05 08:00 -- °C 

5/24/05 17:00 CWMW Depth -- feet Missed transmission 

through 

5/25/05 08:00 -- feet 

7/10/05 21:00 JHAW TDG 857 mm Hg Sensor drift 

through 

7/12/05 14:00 881 mm Hg 

7/10/05 21:00 JHAW TDG2 874 mm Hg Sensor drift 

through 

7/12/05 14:00 898 mm Hg 

7/16/05 6:00 JHAW TDG2 1000 mm Hg Ruptured membrane 

through 

7/26/05 13:00 1020 mm Hg 

7/27/05 12:00 CCIW TDG 853 mm Hg Technician error 

7/27/05 12:00 Depth 12.8 feet Technician error 

8/17/05 10:00 JHAW TDG2 -- mm Hg Ruptured membrane 

through 

8/23/05 15:00 -- mm Hg 

8
Table 3. Missing or deleted data, water year 2005—continued 

[Site abbreviations: WRNO, Warrendale; CCIW, Cascade Island; TDDO, The Dalles tailwater; BON, Bonneville forebay; JDY, 

John Day navigation lock; CWMW, Camas; JHAW, John Day tailwater. Date format: month/day/year. Parameter and unit abbreviations: TDG, total dissolved gas; --, no data; mm Hg, millimeters of mercury; BP, barometric pressure; WT, water 

temperature; °C, degrees Celsius] 

Date & Time Site Parameter Value Unit Reason / Notes 

8/24/05 15:00 CCIW TDG 0 mm Hg Site calibration 

8/24/05 15:00 CCIW WT 0 °C Site calibration 

8/24/05 15:00 CCIW Depth 0 feet Site calibration 

8/24/05 16:00 CCIW TDG 0 mm Hg Site calibration 

8/24/05 16:00 CCIW Depth 0 feet Site calibration 

8/29/05 02:00 JHAW TDG 824 mm Hg Sensor drift 

through 

9/7/05 13:00 740 mm Hg 

8/31/05 16:00 CCIW TDG 1200 mm Hg Ruptured membrane 

through 

9/8/05 12:00 1140 mm Hg 

9/8/05 13:00 CCIW TDG 0 mm Hg Site calibration 

9/8/05 13:00 CCIW BP 0 mm Hg Site calibration 

9/8/05 13:00 CCIW WT 0 °C Site calibration 

9/8/05 13:00 CCIW Depth 0 feet Site calibration 

9/25/05 0:00 WRNO TDG 806 mm Hg Ruptured membrane 

through 

9/29/05 11:00 829 mm Hg 

At the Warrendale site, there were 94 hours of missing TDG data (table 2), resulting in 98.9% of 

the data being received and passing quality assurance criteria. Most of this loss of data occurred in September (table 3), and was due to the rupture or tear of the TDG sensor membrane. 

Quality-Assurance Data 

Data collection for TDG, barometric pressure, and water temperature involve several qualityassurance procedures, including calibration of instruments in the field and in the laboratory, daily checks 

of the data, and data review and archive. These methods are explained in detail in Tanner and Johnston 

(2001), and the results of the quality-assurance data for water year 2005 are presented in this section. 

After field deployment of the Hydrolabs for 2 to 3 weeks, the TDG sensors were calibrated in the 

laboratory. First, the instrument was tested, with the membrane in place, for response to increased pressure and to super-saturation conditions. The membrane was then removed from the sensor and allowed 

to dry for at least 24 hours. Before replacing the membrane, the TDG sensor was examined independently. The calibration test procedure compared the reading of the TDG sensor to barometric pressure as 

measured by a calibrated aneroid barometer. Using a certified digital pressure gage as the primary standard, the TDG sensor was calibrated at added pressures of 100, 200, and 300 mm Hg above barometric 

9
pressure (113%, 126%, and 139% saturation, respectively). The accuracy of the TDG sensors was calculated by computing the difference between the expected reading and the TDG sensor reading (expected 

minus actual) for each of the four test conditions and dividing by the barometric pressure. As shown in 

figure 2, all of the sensor readings were within 0.5% saturation after 2 to 3 weeks of deployment. CERTIFIED PRESSURE GAGE VALUE MINUS FIELD TOTAL-DISSOLVED-GAS INSTRUMENT VALUE, IN PERCENT SATURATION

Data values

outside the

10th and 90th

percentiles

90th percentile

75th percentile

Median

25th percentile

10th percentile

EXPLANATION

APPROXIMATE CALIBRATION TEST

CONDITION, IN PERCENT SATURATION

100 113 126 139

0

-1.0

-0.5

0.5

1.0

Figure 2. Accuracy of total-dissolved-gas sensors after 2 to 3 weeks of field deployment 

The differences in barometric pressure, water temperature, and TDG between the secondary 

standard instruments and the fixed-station monitors after 2 to 3 weeks of field deployment were measured and recorded as part of the field inspection and calibration procedure. These differences, defined as 

the secondary standard minus field instrument, were used to compare and quantify the precision between 

the two independent instruments. For water temperature and TDG, the measurements were made in-situ 

with the secondary standard (a recently calibrated Hydrolab) positioned alongside the field Hydrolab in 

the river. An aneroid barometer, calibrated every 6 to 8 weeks, served as the secondary standard for 

barometric pressure. Figures 3, 4, and 5 illustrate the distribution of quality assurance data for each of 

the three parameters from all eight field sites. 

10
-4

-3

-1

-2

1

2

4

3

SITE IDENTIFIER AND NUMBER OFSAMPLES

JDY JHAW TDA TDDO BON CCIW CWMW

N = 12 N = 12 N = 12 N = 12 N = 22 N = 12

WRNO

N = 22 N = 12

SECONDARY STANDARD VALUE

MINUS FIELD INSTRUMENT VALUE,

IN PERCENT SATURATION 0

Data values

outside the

10th and 90th

percentiles

90th percentile

75th percentile

Median

25th percentile

10th percentile

EXPLANATION

Figure 3. Difference between the secondary standard and the field barometers after 2 to 3 weeks of 

field deployment 

-4

-3

-1

-2

1

2

4

3

SITE IDENTIFIER ANDNUMBEROFSAMPLES

JDY JHAW TDA TDDO BON CCIW CWMW

N = 12 N = 12 N = 12 N = 12 N = 22 N = 9

WRNO

N = 22 N = 13

SECONDARY STANDARD VALUE

MINUS FIELD INSTRUMENT VALUE,

IN PERCENT SATURATION 0

Data values

outside the

10th and 90th

percentiles

90th percentile

75th percentile

Median

25th percentile

10th percentile

EXPLANATION

Figure 4. Difference between the secondary standard and the field temperature instruments after 

2 to 3 weeks of field deployment 

11
-6

-2

-4

2

4

6

SITE IDENTIFIER AND NUMBEROFSAMPLES

JDY JHAW (1) TDA TDDO BON CCIW CWMW

N = 12 N = 12

JHAW (2)

N = 10 N = 12 N = 12 N = 22 N = 10

WRNO

N = 21 N = 13

SECONDARY STANDARD VALUE

MINUS FIELD INSTRUMENT VALUE,

IN PERCENT SATURATION 0

Data values

outside the

10th and 90th

percentiles

90th percentile

75th percentile

Median

25th percentile

10th percentile

EXPLANATION

Figure 5. Difference between the secondary standard and the field total-dissolved-gas instruments 

after 2 to 3 weeks of field deployment 

The comparisons of the aneroid barometer and the electronic field barometers are shown in figure 3. Most of the field values are within 1 mm Hg of the standard values, and all but one are within 2 

mm Hg. The greatest difference (-3mm Hg) was recorded at John Day navigation lock. The secondary 

standard temperature sensor and the field temperature sensor results are presented in figure 4. All of the 

differences are within 0.2 °C (degrees Celsius), and most are within 0.1 °C. 

The differences between the secondary standard TDG sensor and the field TDG sensors were 

calculated following equilibration of the secondary standard unit to the site conditions before removing 

the field unit. The side-by-side equilibrium was considered complete after a minimum of 30 minutes 

when the TDG values for each sensor remained constant for 4 to 5 minutes. As shown in figure 5, most 

of the data demonstrates less than 1% saturation difference between the two TDG sensors. 

The three most anomalous TDG data points were the +3.3% and +4.6% saturation at the John 

Day tailwater primary sensor, JHAW(1), and +4.8% saturation at Cascade Island (figure 5). The outlying data points at John Day tailwater were recorded by different Hydrolab units. Both these TDG 

sensors passed post-deployment calibration tests. It is possible that a problem has developed at the deployment site (sediment build-up within the instrument housing, for example) that interfered with the 

sensors. Further instrument tests and site inspections will be conducted before installation of the site in 

spring 2006. The outlying data point at Cascade Island was the result of a malfunctioning TDG sensor. 

The unit was removed from service and returned to the manufacturer for repair. 

Effects of Spill on Total Dissolved Gas 

Spill from each dam increased the level of total dissolved gas downstream. Spill data in this report are from the USACE Website (http://www.nwd-wc.usace.army.mil/tmt/wcd/tdg/months.html). Spill 

from John Day Dam occurred from April 10 to August 31 (fig. 6). As shown in figure 6, data were missing from both TDG sensors for a period in July (deleted due to poor quality). After August 29, the 

primary sensor failed and the data shown in figure 6 are from the secondary sensor. The spill from April 

10 to June 20 was usually less than 150,000 ft3

/s (cubic feet per second) and usually occurred only between 7:00 p.m. and 7:00 a.m. for fish passage considerations. Figure 6 shows that TDG downstream 

from John Day Dam increased in response to spill from the dam, with the TDG level usually being less 

than 120% saturation. From June 21 to August 31, continuous spill from John Day Dam varied from 

12
about 20,000 ft3

/s to about 80,000 ft3/s, and the TDG at the John Day tailwater site was always less than 

120% saturation. 

Spill from The Dalles Dam (fig. 7) was almost continuous at levels generally between 40,000 

and 80,000 ft3/s from April 11 to August 31. TDG levels at The Dalles tailwater site generally were less 

than 120% saturation during the period of spill. 

Spill from Bonneville Dam was continuous from April 15 to August 31. After May 11, the spill 

generally was 75,000 ft3/s during the daylight hours and between about 100,000 and 150,000 ft3/s at 

night. During that time, the TDG concentration exceeded 120% saturation several times at Warrendale 

(fig. 8) and at Cascade Island (fig. 9). 

13
50

0

100150200

D

95

100105110115120125130

NECR N, IN PEOITARUTASASG-DELVOSSIDL-ATOTNOCESREPT EEFCBIUCD ANUSOHT , INLL PIST

Oregon and Washington variance for tailwater

TDG SATURATION BELOW JOHN DAY DAM, 2005

APRIL

5 10 20 30 10 20 30

JUNE

10 20 30

JULY

10 20 30

MAY

APRIL

5 10 20 30 10 20 30

JUNE

10 20 30

JULY

10 20 30

MAY

SPILL FROM JOHN DAY DAM, 2005

Figure 6. Total dissolved gas saturation downstream from John Day Dam and spill from John Day Dam, April 5 to Septembe

solved gas. 

14
50

0

100150200

D

100105110115120125

NECRE N, IN POITARUTASASG-DEVLOSSIDL-ATOTNOCESREFEET PCBIUCD ANUS HOT , INSPILLT

Oregon and Washington variance for tailwater

TDG SATURATION AT THE DALLES TAILWATER, 2005

APRIL

5 10 20 30 10 20 30

JUNE

10 20 30

JULY

10 20 30

MAY

APRIL

5 10 20 30 10 20 30

JUNE

10 20 30

JULY

10 20 30

MAY

SPILL FROM THE DALLES DAM, 2005

Figure 7. Total dissolved gas saturation downstream from The Dalles Dam and spill from The Dalles Dam, April 5 to Septem

dissolved gas. 

15 
50

0

100150200

D

100105110115120125

NECRE N, IN POITARUTASASG-DEVLOSSIDL-ATOTNOCESREFEET PCBIUCD ANUS HOT , INSPILLT

Oregon and Washingt

TDG SATURATION AT WARRENDALE, 2005

APRIL

5 10 20 30 10 20 30

JUNE

10 20 30

JULY

10 20 30

MAY

APRIL

5 10 20 30 10 20 30

JUNE

10 20 30

JULY

10 20 30

MAY

SPILL FROM BONNEVILLE DAM, 2005

Figure 8. Total dissolved gas saturation downstream from Bonneville Dam at Warrendale and spill from Bonneville Dam, Apr

TDG, total dissolved gas.

16
50

100150200

SPILL, INTHOUSANDCUBICFEET PERSECOND

100105110115120125

NERC N, IN PEOITARUTSASAG-DVEOLSSID-LATOTT

Oregon and Washing

TDG SATURATON AT CASCADE ISLAND, 2005

APRIL

5 10 20 30 10 20 30

JUNE

10 20 30

JULY

10 20 30

MAY

APRIL

5 10 20 30 10 20 30

JUNE

10 20 30

JULY

10 20 30

MAY

SPILL FROM BONNEVILLE DAM, 2005

Figure 9. Total dissolved gas saturation downstream from Bonneville Dam at Cascade Island and spill from Bonneville Dam, 

2005. TDG, total dissolved gas. 

17 
The forebay sites, John Day navigation lock, The Dalles forebay, Bonneville forebay, and 

Camas, were located immediately upstream of a dam, except for Camas, which is located 24.4 miles 

downstream of Bonneville Dam. As a result, the forebay sites were expected to have lower levels of total dissolved gas. At John Day navigation lock (fig. 10), TDG saturation was less than 115% saturation 

with the exception of 2 days, May 27 and May 28. At The Dalles forebay (fig. 11), TDG saturation was 

periodically above 115% saturation for short periods in April and May. At Bonneville forebay (fig. 12), 

TDG saturation was more than 115% a few times in May. Finally, at Camas (fig 13), TDG saturation 

was higher than 115% on several occasions from April to August. As documented previously (Tanner 

and Bragg, 2001), some of the daily increases in TDG at Camas may have been due to the production of 

oxygen by aquatic plants and to temperature variations. 

18
JOHN DAY DAM FOREBAY, 2005

APRIL

5 10 20 30 10 20 30

JUNE

10 20 30

JULY

10 20 30

MAY

Oregon and Washington v

TOTAL-DISSOLVED-GASSATURATION, INPERCENT

100105110115120

Figure 10. Total dissolved gas saturation upstream from John Day Dam, April 5 to September 5, 2005 

THE DALLES DAM FOREBAY, 2005

APRIL

5 10 20 30 10 20 30

JUNE

10 20 30

JULY

10 20 30

MAY

Oregon and Washington v

TOTAL-DISSOLVED-GASSATURATION, INPERCENT

95

100105110115120

Figure 11. Total dissolved gas saturation upstream from The Dalles Dam, April 5 to September 5, 2005 

19 
BONNEVILLE DAM FOREBAY, 2005

APRIL

5 10 20 30 10 20 30

JUNE

10 20 30

JULY

10 20 30

MAY

Oregon and Washington va

TOTAL-DISSOLVED-GASSATURATION, INPERCENT

100105110115120

Figure 12. Total dissolved gas saturation upstream from Bonneville Dam, April 5 to September 5, 2005 

CAMAS, 2005

APRIL

5 10 20 30 10 20 30

JUNE

10 20 30

JULY

10 20 30

MAY

Oregon and 

TOTAL-DISSOLVED-GASSATURATION, INPERCENT

100105110115120

Figure 13. Total dissolved gas saturation at Camas, April 5 to September 5, 2005 

20
Comparison of Total Dissolved Gas and Temperature to Standards 

In 2005, there were variances or exceptions to the water-quality standard for TDG of 110% saturation. These variances were established to allow spill for fish passage at dams on the Columbia River. 

The State of Oregon granted a multiyear variance, covering 2003 to 2007 (Stephanie Hallock, Oregon 

Environmental Quality Commission, written commun., 2003). The State of Washington provided for 

fish passage in its water quality standards consistent with approved gas abatement plans (Washington 

Administrative Code 173-201A-200(1)(f), http://www.leg.wa.gov/WAC/index.cfm?section=173-201A200&fuseaction=section, accessed November 10, 2005). From April 1 to August 31, 2005, the USACE 

was granted variances of 115% for forebay sites (John Day navigation lock, The Dalles forebay, Bonneville forebay, and Camas) and 120% for tailwater sites, directly downstream from dams (John Day 

tailwater, The Dalles tailwater, and Warrendale). The 115% and 120% variances were exceeded if the 

average of the highest 12 hourly values in 1 day (1:00 a.m. to midnight) was larger than the numerical 

standard. A separate variance of 125% was in place for all sites for the highest 2-hour average (Oregon 

Environmental Quality Commission, written commun., 2003), or the highest 1-hour average (Washington Administrative Code 173-201A-200(1)(f), http://www.leg.wa.gov/WAC/index.cfm?section=173-

201A-200&fuseaction=section, accessed November 10, 2005). Although the Camas site is not located at 

the forebay of a dam, it is 24.4 miles downstream from Bonneville Dam and is regulated as a forebay 

site. 

There was no water-quality variance in place for the site at Cascade Island. This site was established in 2004 for the purpose of collecting data directly in the spillway of Bonneville Dam. The 

USACE did not use TDG data from the Cascade Island site to regulate spill or flow on the Columbia 

River. 

At five of the eight monitoring stations, the Oregon and Washington variance for TDG was exceeded at some time during water year 2005 (table 4). Table 4 includes data from Cascade Island; even 

though there was no variance for that site, it was grouped in the category tailwater sites with a variance 

of 120% saturation. The site with the most exceedances was Camas, which exceeded the 115% variance 

11 times. There were no exceedances at the following tailwater sites: The Dalles tailwater, Cascade Island, and Warrendale. 

Table 4. Exceedances of States of Oregon and Washington water-quality variances for total dissolved gas, lower Columbia River, Oregon and Washington, water year 2005 

Abbreviated 

station name 

Numerical variance for 

total dissolved gas, in 

percent saturation 

Number of days 

in exceedance 

of variance 

John Day navigation lock 115 1 

John Day tailwater 120 3 

The Dalles forebay 115 3 

The Dalles tailwater 120 0 

Bonneville forebay 115 3 

Cascade Island 120 0 

Warrendale 120 0 

Camas 115 11 

21
The distribution of TDG values for the spill season (April 10 to August 31, 2005) is shown in 

figure 14. The applicable variance is shown with the data for each site, along with the number of exceedances of each variance. At several sites (for instance, Warrendale), there were several hourly TDG 

values larger than the variance, but the number of exceedances was still zero because the highest 12-

hour average was below the numerical limit. Data from the forebay sites show an increase in the median 

TDG (from JDY to TDA to BON to CWMW), which probably reflects the river’s inability to degas to a 

“baseline” level downstream of each dam before another dam is encountered to again cause an increase 

in TDG. 

JDY JHA W TDA TDD O BO N CCIW WRNO CWMW 95

100

105

110

115

120

125

N = 344 9 N = 341 5 N = 345 7 N = 345 7 N = 345 7 N = 344 4 N = 345 7 N = 344 0

TOTAL-DISSOLVED-GAS SATURATION, IN PERCENT

Data values outside the

10t h and 90t h percen tiles

90t h percentile

75t h percentile

Med ian

25t h percentile

10t h percentile

EXPLANATION

11

Tailwater sites

Number of

exceedance s of

variance

Foreba y sites

1

3

3

3

0

0

0

11

SITE IDENTIFIER AND NUMBER OF SAMPLES

Oregon and Washington variance for tailwater

Oregon and Washington

variance for forebay water

Figure 14. Distributions of hourly total-dissolved-gas data and exceedances of Oregon and 

Washington water-quality variances, April 10, 2005, to August 31, 2005 

Water temperature standards that apply to the lower Columbia River are complex and depend on 

the effects of human activities and the locations of salmonid rearing, spawning, and egg incubation areas. According to the State of Oregon water-quality standard, the 7-day-average maximum temperature 

of the lower Columbia River should not exceed 20 °C (Oregon Department of Environmental Quality, 

Temperature Criteria Rules OAR 340-041-0028, modified 05/20/2004, at 

http://www.deq.state.or.us/wq/wqrules/Div041/OAR340Div041.pdf, accessed November 10, 2005). Washington State regulations state that the water temperature in the Columbia River shall not exceed a 1-day 

maximum of 20.0 °C due to human activities (Water Quality Standards for Surface Waters of the State 

of Washington, Chapter 173-201A WAC, amended July 1, 2003, 

http://www.ecy.wa.gov/pubs/wac173201a.pdf, accessed November 10, 2005). 

Water temperatures upstream and downstream from John Day Dam (fig. 15), The Dalles Dam 

(fig. 16), Bonneville Dam (fig. 17); and at Cascade Island (fig. 18) were equal to or larger than 20.0 °C 

continuously from mid-July until the end of monitoring in early September. Water temperatures at the 

22
forebay sites were approximately equal to the temperatures at the tailwater sites, indicating well-mixed 

conditions in the forebays. 

17

18

19

20

21

22

23

24

WATER TEMPERATURE, IN DEGREES CELSIUS

10 20 30 10 20 30 6

Columbia River at John Day navigation lock

Columbia River at John Day tailwater

JOHN DAY, 2005

SEPTEMBER JULY AUGUST

Figure 15. Water temperature upstream and downstream from John Day Dam, summer 2005 

17

18

19

20

21

22

23

24

WATER TEMPERATURE, IN DEGREES CELSIUS

JULY

10 20 30

AUGUST SEPTEMBER

10 20 30 6

THE DALLES, 2005

Columbia River at The Dalles forebay

Columbia River at The Dalles tailwater

Figure 16. Water temperature upstream and downstream from The Dalles Dam, summer 2005 

23
17

18

19

20

21

22

23

24

WATER TEMPERATURE, IN DEGREES CELSIUS

JULY

10 20 30

AUGUST SEPTEMBER

10 20 30 6

BONNEVILLE AND WARRENDAL E, 200 5

Columbia River at Bonneville forebay

Columbia River at Warrendale

Figure 17. Water temperature upstream and downstream from Bonneville Dam, summer 2005 

17

18

19

20

21

22

23

24

WATER TEMPERATURE, IN DEGREES CELSIUS

JULY

10 20 30

AUGUST SEPTEMBER

10 20 30 6

CASCADE ISLAND, 2005

Figure 18. Water temperature at Cascade Island, summer 2005 

24
Water temperature differences between the sites at John Day navigation lock (river mile 215.7) 

and Warrendale (river mile 140.4) in late summer were unusual (fig. 19). In July and early August, temperatures at the two sites were nearly the same, whereas later in the summer, the water temperature at 

Warrendale was about 1 °C less than at the John Day site, upstream. Summer air temperatures commonly have larger maxima east of the Cascades compared with those on the west, which probably 

explains the difference in water temperatures. 

17

18

19

20

21

22

23

24

WATER TEMPERATURE, IN DEGREES CELSIUS

10 20 30

SEPTEMBER

10 20 30 6

JOHN DAY AND WARRENDALE, 2005

Columbia River at Warrendale

Columbia River at John Day navigation lock

JULY AUGUST

Figure 19. Water temperature at John Day navigation lock and Warrendale, summer 2005 

25
At the Camas site, the water temperature also was 20 °C or higher from mid-July until the end of 

monitoring in early September (fig. 20). As in the past, there was a distinct daily cycle to temperature, 

with an amplitude of about 1 °C, the minimum occurring at about 0900 and the maximum at about 1900. 

17

18

19

20

21

22

23

24

WATER TEMPERATURE, IN DEGREES CELSIUS

10 20 30 10 20 30 6

CAMAS, 2005

JULY AUGUST SEPTEMBER

Figure 20. Water temperature at Camas, summer 2005 

References Cited 

 Colt, J. 1984. Computation of dissolved gas concentrations in water as functions of temperature, salinity, and pressure: American Fisheries Society Special Publication 14, 154 p. 

Jones, J. C., Tracey, D. C., and Sorensen, F. W., eds., 1991, Operating manual for the U.S. Geological 

Survey’s data-collection system with the Geostationary Operational Environmental Satellite: U.S. 

Geological Survey Open-File Report 91-99, 237 p. 

Tanner, D.Q., and Bragg, H.M., 2001, Quality-assurance data, comparison to water-quality standards, 

and site considerations for total dissolved gas and water temperature, lower Columbia River, Oregon 

and Washington, 2001: U.S. Geological Survey Water-Resources Investigations Report 01-4273, 

14 p. 

Tanner, D.Q., Bragg, H.M., and Johnston, M.W., 2003, Total dissolved gas and water temperature in the 

Lower Columbia River, Oregon and Washington, 2003—Quality-assurance data and comparison to 

water-quality standards: U.S. Geological Survey Water-Resources Investigations Report 03-4306, 18 

p. 

Tanner, D.Q., Bragg, H.M., and Johnston, M.W., 2004, Total dissolved gas and water temperature in the 

Lower Columbia River, Oregon and Washington, 2004—Quality-assurance data and comparison to 

water-quality standards: U.S. Geological Survey Scientific Investigations Report 2004-5249, 20 p. 

26
Tanner, D. Q., Harrison, H. E., and McKenzie, S. W., 1996, Total dissolved gas, barometric pressure, 

and water temperature data, lower Columbia River, Oregon and Washington, 1996: U.S. Geological 

Survey Open-File Report 96-662A, 85 p. 

Tanner, D. Q. and Johnston, M. W., 2001, Data-collection methods, quality-assurance data, and site considerations for total dissolved gas monitoring, lower Columbia River, Oregon and Washington, 2000: 

U.S. Geological Survey Water-Resources Investigations Report 01-4005, 19 p. 

Tanner, D.Q., Johnston, M.W., and Bragg, H.M., Total dissolved gas and water temperature in the 

Lower Columbia River, Oregon and Washington, 2002—Quality-assurance data and comparison to 

water-quality standards: U.S. Geological Survey Water-Resources Investigations Report 02-4283, 

12 p. 

U.S. Environmental Protection Agency, 1986, Quality criteria for water: Washington, D.C., 

EPA-440-5-86-001. 

27