United State'^ Departmpnt of the Tr-^'^H.or, 0<^^-ar Lo Chapman^ Secretary 

 Fish and Wildlife Service,, Albert Mo Day, Director 



Special Scientific Reports Fisheries Noo 75 



WATER TEMPERATURES OF CALIFORNIA'S CENTRAL VALLEY, 19U9-51 

 By Oliver B. Cope, Fishery Research Biologist 



A previous report (Cope 19h9) by the Fish and Wildlife Service brought 

 together a mass of water- temperature readings from streams in the Central 

 Valley of California from 1939 to 19li8„ Additional records, collected 

 since the first report, are presented here to bring the da+a to the end of 

 1951. 



Water=temperature data are valuable to several agencies working in 

 the Sacramento River basin„ Fishery researchers are interested in relations 

 between water temperatures and the times and extent of fish migrations, sea- 

 sonal effects on the sizes of fish movements, and effects on other factors 

 of the environment of fish. Another group has need for water temperature 

 data for the purpose of predicting changes in water due to Federal water- 

 use projects (Erkkila et al, 195o) 5 only with a background of temperature . 

 readings taken under various environmental conditions can such predictions 

 be made. Engineers concerned with irrigation and recreation, sanitation 

 and pollution specialists, and park and forest administrators also desire 

 such information. 



As in the first report, all records are from streams in Northern 

 Californiao The present collection is further restricted to waters of the 

 Sacramento Valley and the Sacramento - San Joaquin Delta areao 



All temperature readings were recorded by members of the Fish and 

 Wildlife Service, irith the exceotion of readings from Sacramento River near 

 the Sacramento Water Works and Sacramento River at Hay^s Landing and Lowry's 

 Landing, The City of Sacramento Division of Water and Sewers contributed 

 the Sacramento Water Works records, and Sacrajtiento State College maintained 

 a Fish and Wildlife Service thermograph at Hay's Landing and Lowry's 

 Landing. 



