Stream Thermograph Meeting - 24 Feb 1994

Present: Stan Gregory, Randy Wildman, John Moreau, Don Henshaw

Action Items:

1. Replace stream/air thermographs with CR10 stream/air thermisters at existing Upper Lookout and McRae Creek sites. Reposition air temperature probe at Upper Lookout to a more representative location.

2. Remove stream mercury probe at Mack Cr site above gaging station. Air temperature under the canopy is still necessary. Continue collection of air temperature using thermograph chart. Possibly use this site to simultaneously run a Hobo air temperature probe to compare against the thermograph. Eventually replace with a CR10 or Hobo.

3. Remove thermograph and discontinue collection of temperature data at Quartz Creek site.

4. Install new sites at the confluence of Mack and Lookout and the confluence of McRae and Lookout. Randy will assist John in locating temperature probes. Stream temperature will be measured in each tributary. If possible, stream temperature will be measured far enough downstream to record true mixing temperature (at least 50m). Air temperature will also be measured at a height of at least one meter and away from artificial heat sources for true ambient air temperature.

5. Install a new site at the Lookout Creek Gaging Station to measure stream and air temperature. John has contacted Jim Pool at USGS and has learned we can use the gaging station to house our CR10.

6. CR10 stream/air thermister stations will record hourly mean temperature, daily max and min, and time of max and min.

Other discussion:

-> Stan has pledged up to $3000 maximum for CR10 instrumentation for these stations, and has donated one CR10.

-> The cost of one CR10 with wiring panel is $1090. The higher precision thermisters are $50 (.1 degree precision). Thermocouple wire is available, but has only .8 degree precision.

-> All mercury probes used with stream thermographs will be removed from streams.

-> Thermisters must be submerged at low flow. Stan suggested locating the probes within heavy metal pipe for protection with more accurate measurement.

-> Water depth measures are desireable. Potentially, McRae Cr could be used to experiment with pressure transducers in a stilling well type setup to measure depth.

-> At the new confluence sites, attempts will be made to measure true mixing temperature downstream. Relative discharge from the tributaries can be calculated from mixing temperatures.

-> Thermograph chart digitizing has yielded stream temperatures of -1 to -2 degrees C. Stan noted that he has never seen temperatures lower than .5 or 1 at Mack. Super cooling can occur with slush, but minimum temperatures would only be -.1 to -.2 degrees C.

-> Max-min stream temperature was recorded at the Lookout Creek Gaging Station from WY 1952-1955 and WY 1964-1981. We have received these data files from USGS. Stan suggested we try to recreate the entire record from our existing thermograph stations using regression techniques, and suggested we talk to David Greenland.

-> We should contact the USGS regarding using the Lookout Creek Gaging Station to house our CR10 instrument. Ian Waite of USGS is using the Andrews reference system on Mack Creek for his bug and fish research, and might be an asset in allowing us access to this station. (Note: USGS has granted us permission to use this station.)