nearly complete analysis of water temperatures will follow. However, in 

 order to make temperature records already recorded available to agencies 

 interested in manapement of Willamette River fisheries j the temperature 

 data are presented in this report in tabular and graphic formo 



THERMOGRAPH STATIONS 



The Uo Se Arnry Corps of Engineers and Fish and Vii'ildliie Service 

 cooperated in planning for the survey of Willamette River System water 

 temperatures and in selection of thermograph stations. The limited 

 number of thermographs available for the investigation influenced the 

 location of stations. 



Stations were selected to include two establisVied reservoirs 

 (Cottage Grove and Dorena) and tvfo reservoirs under construction and not 

 yet impounding viater (Detroit and Meridian) » At all four, thermographs 

 were operated in the streams upstream and dovmstream from the reservoirs. 

 Upstream recorders were located just above the maximum impoundment 

 influences of the reservoirs and downstream instruments within one-half 

 mile of reservoir discharge gates „ Additional stations were located on 

 the McKenzie River near Walterville,, North Santiam River at Jefferson, 

 Long Tom River at Monroe, Breitenbush River at Camp Mongold, and on the 

 main stem of ■che Willamette River at Corvallis and Eugene, 



THERMOGRAPH OPERATION 



All water temperatures except those for Eugene were recorded by 

 constant-recording thermographs specified by the manufacturers to be 

 capable of recording temperatures accurately within one-half of 1 degree 

 Fahrenheit v,rith a range from .32° to 8$'^. Some thermographs which had 

 been in operation for four seasons failed to maintain this accuracy. It 

 was necessary to make several calibrations during the season and to 

 correct for errors , Eugene temperatures were tabulated from hourly 

 cooling-water temperatures recorded by operating staff at the Eugene 

 Water and Electric Board's Steam Plant at Eugene, 



One thermograph had been in operation at Corvallis during 19U8 and 

 19h9o The temperature records for Corvallis include these two years in 

 separate tables. 



To obtain representative water temperatures, the bulbs of the 

 instruments were placed in the streams where the water was well mixed. 

 To assure precision the instruments were carefully calibrated in the 

 field at intervals of about six weeks. Four field calibrations were 

 made on each instrument during the season., 



