It should be apparent, from the foregoing statements, that care- 

 ful interpretation of the data collected is extremely iinportant in assess- 

 ing the relationship between aquatic life emd its environment. In this 

 respect, the more factors that can be measured, and the more data on hand, 

 the more meaningful this interpretation can become. Therefore, as time 

 permitted, data from other segments of the Sacramento River investigation 

 vere used to supplement those gathered in the biologiceO. sxirvey. 



Because of time limitations, it has not been possible to make 

 a complete ecological interpretation of the data collected during the 

 biological phase of the Sacramento River Water Pollution Survey with data 

 from other portions of the investigation. 



Authorization of Study 

 The biological survey was conducted by personnel of the Depart- 

 ments of Water Resources and Fish and Game in accordance with Interagency 

 Agreements No. 251I+I and No. 25093 . 



Objectives and Scope of Study 



The biological portion of the Sacramento River Water Pollution 

 Survey was designed to: (l) establish a "base-line" of present biologi- 

 cal conditions against which future changes caji be measured, and (2) pro- 

 vide information necessary for setting waste discharge requirements for 

 the protection of aquatic life. 



In order to meet these objectives, biologiceO. sampling was con- 

 ducted at monthly intervals from April I96O through June I961 at twenty- 

 two "key" sampling stations from Shasta Dam to the confluence of the 

 Sacramento and San Joaquin Rivers (Plate l) . Seven additionetl river sta- 

 tions were established to measure biological conditions in areas of 

 particular interest. Two large agricultursQ. irrigation drains were 



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