Prepared in cooperation with the Bureau of Reclamation

Thermal Profiles for Selected River Reaches of the 

Methow and Chewuch Rivers, Washington, August 2011

U.S. Department of the Interior

U.S. Geological Survey

Data Series 682

Thermal Profiles for Selected River Reaches 

of the Methow and Chewuch Rivers, 

Washington, August 2011

By Andrew S. Gendaszek

Prepared in cooperation with the Bureau of Reclamation

Data Series 682 

U.S. Department of the Interior

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

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2012

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Suggested citation:

Gendaszek, A.S., 2012, Thermal profiles for selected river reaches of the Methow and Chewuch Rivers, Washington, 

August 2011: U.S. Geological Survey Data Series 682, 4 p.
iii

Contents

Abstract ..........................................................................................................................................................1

Introduction ....................................................................................................................................................1

Purpose and Scope ..............................................................................................................................1

Description of Study Area ...................................................................................................................1

Thermal Profile Survey..................................................................................................................................1

Distribution of Information ...........................................................................................................................4

Acknowledgments.........................................................................................................................................4

References Cited............................................................................................................................................4

Figures

Figure 1. Map showing location of study area where stream-water-temperature profiles

were measured on the Methow and Chewuch Rivers, Washington .................. 2

Figure 2. Graph showing near-streambed temperature during the ambient streamflow

survey of the Methow River (river mile [RM] 49.0 and 52.1), Washington,

August 11, 2011 .............................................................................. 3

Figure 3. Graph showing near-streambed and near-surface temperatures during the

traverse stream survey of the Methow River (river mile [RM] 49.0 and 52.1),

Washington, August 11, 2011............................................................... 3

Figure 4. Graph showing near-streambed and near-surface temperatures during the

ambient streamflow survey of the Chewuch River (river mile [RM] 0.8 and 1.0),

Washington, August 11, 2011............................................................... 3

Tables

Table 1. Near-streambed temperature and Global Positioning System location data during

the ambient streamflow survey of the Methow River (river mile 49.0 and 52.1),

Washington, August 11, 2011............................................................... 4

Table 2. Near-streambed temperature and Global Positioning System location data during

the traverse stream survey of the Methow River (river mile 49.0 and 52.1),

Washington, August 11, 2011............................................................... 4

Table 3. Near-surface temperature and Global Positioning System location data during

the traverse stream survey of the Methow River (river mile 49.0 and 52.1),

Washington, August 11, 2011............................................................... 4

Table 4. Near-streambed temperature and Global Positioning System location data

collected during the ambient streamflow survey of the Chewuch River (river mile

0.8 and 1.0), Washington, August 11, 2011 ................................................ 4

Table 5. Near-surface temperature and Global Positioning System location data collected

during the ambient streamflow survey of the Chewuch River (river mile 0.8 and

1.0), Washington, August 11, 2011 ......................................................... 4
iv

Conversion Factors and Datum

Conversion Factors

Multiply By To obtain

mile (mi) 1.609 kilometer (km)

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.

Datum

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).
Thermal Profiles for Selected River Reaches of the 

Methow and Chewuch Rivers, Washington, August 2011

By Andrew S. Gendaszek

Abstract 

Longitudinal profiles of near-streambed and near‐surface 

temperatures were collected for selected reaches of 

the Methow and Chewuch Rivers, Washington, during 

August 2011 to facilitate development of a stream temperature 

model near the confluence of the Methow and Chewuch 

Rivers. Temperature was measured using a probe with 

an internal datalogger towed behind a watercraft moving 

downstream at ambient river velocity. For the Methow 

River, an additional temperature survey was completed 

using near‐streambed and near-surface probes towed behind 

a second watercraft that traversed the channel to measure 

vertical and lateral temperature variability. All data were 

referenced to location that was concurrently measured with a 

Global Positioning System. Data are presented as Microsoft 

Excel® files consisting of date and time, water temperature, 

and Washington State Plane North easting and northing. 

Introduction 

Longitudinal profiles of near-streambed temperatures 

surveyed at ambient river velocity in a Lagrangian framework 

provide information about potential areas of groundwater 

discharge as well as salmonid habitat and thermal refugia 

(Vaccaro and Maloy, 2006). Longitudinal thermal profiles 

previously have been surveyed in several rivers in Washington, 

including the Yakima River and tributaries (Vaccaro and 

others, 2008), the Nooksack River (Cox and others, 2005), 

and the Stillaguamish River and tributaries (Gendaszek, 

2011). In August 2011, the U.S. Geological Survey (USGS), 

in cooperation with the Bureau of Reclamation (Reclamation), 

surveyed stream temperatures to support development of a 

Reclamation stream temperature model in selected reaches of 

the Methow and Chewuch Rivers, Washington.

Purpose and Scope

The purpose of this report is to present longitudinal 

thermal profiles of stream temperature in selected reaches of 

the Methow and Chewuch Rivers. These data may be used 

to develop a model of stream temperature and as a tool to 

develop a better understanding of groundwater/surface-water 

interactions in the Methow and Chewuch Rivers.

Description of Study Area

The Methow River, in north-central Washington, is joined 

by the Chewuch River at the town of Winthrop (fig. 1). Mean 

annual discharge of the Methow River (Methow River at 

Winthrop, Wash., USGS gaging station 12448500) for water 

years 1991–2010 was 1,167 ft3/s and mean annual discharge 

of the Chewuch River (Chewuch River at Winthrop, Wash., 

USGS gaging station 12448000) for water years 1992–2010 

was 394 ft3/s. River miles (RM) referred to in this report were 

measured from 2011 stream channels.

Thermal Profile Survey

Continuous water temperature was measured at 3- to 

5-second intervals using Solinst® LT Levelogger and Solinst®

LTC Levelogger temperature probes verified by a National 

Institute of Standards and Technology (NIST) certified 

thermistor. Position data were concurrently measured using 

a Trimble R8 GPS or a Garmin® GPSmap® 60Csx GPS. 

Near-streambed temperature probes were towed behind a 

watercraft and dragged along the streambed except when 

in-stream obstacles prevented probe movement downstream. 
2 Thermal Profiles for Selected River Reaches of the Methow and Chewuch Rivers, Washington, August 2011

watac11-0674_fig 01

48°

29’

48°

27’

120° 12’ 120° 10’ 

0

1

53

52

Winthrop

51

50

49

Methow

Riv er Chewuch Ri ver

Hillshade image calculated from 1-meter LiDAR DEM, Puget Sound Lidar Consortium.

LiDAR data acquired 2006.

MILE

0 0.5 1 KILOMETER

0 0.5 1

EXPLANATION

River mile

Methow River

Chewuch River

Thermal profile reach

52

USGS streamflow12448500 gaging station

12448000

12448500

WASHINGTON 

Study Area

Figure 1. Location of study area where stream-water-temperature profiles were measured on the Methow and Chewuch 

Rivers, Washington.
Thermal Profile Survey 3

Near-surface temperature probes were towed behind the 

watercraft within 1 ft of the water surface. The location of 

each temperature measurement was determined by relating 

the time stamps of the Global Positioning System (GPS) data 

to the temperature data. If a GPS location was not recorded 

at the time of a temperature measurement, the location of 

the temperature measurement was determined by linear 

interpolation of the two known GPS locations that bracket the 

time of the temperature measurement. 

A profile of near-streambed temperature for the Methow 

River between RM 49.0 and 52.1 was surveyed on August 11, 

2011, while in a watercraft drifting downstream at ambient 

stream velocity within the thalweg (table 1; fig. 2) using the 

method developed by Vaccaro and Maloy (2006). Profiling 

at ambient stream velocity in a Lagrangian framework 

tracks a parcel of water as it moves downstream during the 

day; departures from the diurnal heating cycle may be due 

to groundwater input, surface-water inflows, or riparian 

shading. Additionally, cross-stream temperature variability 

near the streambed and near the surface was characterized 

by a second watercraft towing probes while traversing the 

channel of the Methow River between RM 49.0 and 52.1 on 

August 11, 2011 (tables 2 and 3; fig. 3). During this traverse 

stream survey, the watercraft crossed the channel two to 

four times at a near perpendicular angle to the thalweg every 

0.1–0.2 mi. Near‐streambed and near-surface temperatures 

also were surveyed on August 11, 2011, between RM 0.8 

and 1.0 of the Chewuch River while in a watercraft drifting 

downstream at ambient stream velocity (tables 4 and 5;

fig. 4). Near‐streambed and near-surface temperatures were 

not surveyed while traversing the channel due to boulder 

obstructions in the Chewuch River.

17

16

15

14

13

Near-streambed 

temperature

RM 52RM 51RM 50RM 49

Time, August 11, 2011

Temperature, in degrees Celsius

1300 1330 1400 1430 1500

EXPLANATION

Figure 2. Near-streambed temperature during the 

ambient streamflow survey of the Methow River (river 

mile [RM] 49.0 and 52.1), Washington, August 11, 2011.

watac11-0674_fig 03 Temperature, in degrees Celsius

Time, August 11, 2011

1300 1330 1400 1430 1500

17

16

15

14

13

RM 52

RM 51RM 50RM 49

Near-streambed temperature

Near-surface temperature

EXPLANATION

Figure 3. Near-streambed and near-surface 

temperatures during the traverse stream survey of the 

Methow River (river mile [RM] 49.0 and 52.1), Washington, 

August 11, 2011.

Temperature, in degrees Celsius

Time, August 11, 2011

1745 1800 1815

17

16

15

14

13

RM 1

Near-streambed temperature

Near-surface temperature

EXPLANATION

Figure 4. Near-streambed and near-surface 

temperatures during the ambient streamflow survey 

of the Chewuch River (river mile [RM] 0.8 and 1.0), 

Washington, August 11, 2011.
4 Thermal Profiles for Selected River Reaches of the Methow and Chewuch Rivers, Washington, August 2011

Distribution of Information 

A Microsoft Excel® file of tables 1–5 that include the 

thermal-profile data for each longitudinal profile is available at

http://pubs.usgs.gov/ds/682/.

Table 1. Near-streambed temperature and Global Positioning 

System location data during the ambient streamflow survey of the 

Methow River (river mile 49.0 and 52.1), Washington, August 11, 

2011.

Table 2. Near-streambed temperature and Global Positioning 

System location data during the traverse stream survey of the 

Methow River (river mile 49.0 and 52.1), Washington, August 11, 

2011.

Table 3. Near-surface temperature and Global Positioning 

System location data during the traverse stream survey of the 

Methow River (river mile 49.0 and 52.1), Washington, August 11, 

2011.

Table 4. Near-streambed temperature and Global Positioning 

System location data collected during the ambient streamflow 

survey of the Chewuch River (river mile 0.8 and 1.0), Washington, 

August 11, 2011.

Table 5. Near-surface temperature and Global Positioning 

System location data collected during the ambient streamflow 

survey of the Chewuch River (river mile 0.8 and 1.0), Washington, 

August 11, 2011.

Acknowledgments

The author would like to thank Jennifer Bountry, Yong 

Lai, and Jason Caldwell of the Bureau of Reclamation and 

John Crandall of the Wild Fish Conservancy for assistance in 

collecting thermal profile data.

References Cited

Cox, S.E., Simonds, F.W., Doremus, Llyn, Huffman, R.L., 

and Defawe, R.M., 2005, Ground water/surface water 

interactions and quality of discharging ground water in 

streams of the lower Nooksack River Basin, Whatcom 

County, Washington: U.S. Geological Survey Scientific 

Investigations Report 2005-5255, 46 p. (Also available at 

http://pubs.er.usgs.gov/publication/sir20055255.)

Gendaszek, A.S., 2011, Thermal profiles for selected river 

reaches in the Stillaguamish River basin, Washington, 

August 2011: U.S. Geological Survey Data Series 654, 

4 p. (Also available at http://pubs.er.usgs.gov/publication/

ds654.)

Vaccaro, J.J., Keys, M.E., Julich, R.J., and Welch, W.B., 

2008, Thermal profiles for selected river reaches in the 

Yakima River basin, Washington: U.S. Geological Survey 

Data Series 342. (Also available at http://pubs.er.usgs.gov/

publication/ds342.)

Vaccaro, J.J., and Maloy, K.J., 2006, A thermal profile 

method to identify potential ground-water discharge 

areas and preferred salmonid habitats for long river 

reaches: U.S. Geological Survey Scientific Investigations 

Report 2006-5136, 16 p. (Also available at http://pubs.

er.usgs.gov/publication/sir20065136.)
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Gendaszek,— Thermal Profiles for Selected River Reaches of the Methow and Chewuch Rivers, Washington, August 2011—Data Series 682