n 



Commission show u chlorine content in the San Joacjuin Ri\x-r at Blake's Landing 

 (Venice Island) in September, 1920, of 56 parts in 100,000 at high tide and 40 parts at 

 low tide, representing about 92 parts and 66 parts of common salt respectively- While 

 a portion of this salt is probably attributalile to the presence of some bay water, care 

 is necessary in interpreting this information in view of the report of W. E. Allen on 

 "A Quantitati\e and Statistical Study of the Plankton of the San Joaquin River and its 

 Tributaries in and near Stockton, California, in 1913," in which he says on page 21: 

 "In spite of the low water it is not at all probable that sea water ever had any influence 

 here except in causing tides." He then notes the salinity of the river water at a point 

 in the river from 400 to 800 yards up-stream from the mouth of Stockton channel at 

 about 30 day intervals throughout the year. The highest salinity (uninfluenced by 

 ocean water) was shown by the samples taken on November 22nd. The chlorine 

 content of the water was then 66 parts in 100,000. This is equivalent to about 99 parts 

 of common salt in 100,000 parts of water. The situation relating to the up-river pene- 

 tration of bay water is aggravated by the fact that the work of channel enlargement 

 on the Sacramento Ri\-er below Rio Vista, in progress since 1913 and being done by 

 the U. S. Government in cooperation with the State of California, has been a material 

 factor in facilitating tidal flow in the lower reaches of that ri\er and in augmenting the 



TABLE 3 



Range of S.^linity i\ the Lower Re.\ches of Sacramento 



AND San JOAQIUN RnERS AND IN THE HeAD OF SuiSUN BaY IN 1920 



Based on samples taken for the California State Water Commission at high and low tides. Salinity 

 is given in parts of salt per 100,000 parts of water. (Reduced from chlorine contents by Knudsen's 

 formula.) 



Station 



Rio Vista . 



Collinsville. 



S. F.-S. R. R. 

 O. A. & E. R. R. 



Ferry, Suisun I3ay 



Antioch 



Tide 



Low 

 High 



Low 

 High 



Low 



High 



Low ) 

 High/ 



*June 



5 to 20 

 10 to 130 



*July 



22 to 35 



18 to 525 



55 to 930 



17 to 640 



.\ugust 



49 to 240 

 49 to 380 



\ 650 to 1220 

 ( 825 to 1445 



September 



50 to 160 

 105 to 430 



875 to 1345 

 1210 to 1560 



11045 to 1285 1310 to 1700 

 (1060 to 1590 1670 to 1800 



275 to 865 

 665 to 1350 



October 



780 to 975 

 1040 to 1390 



18 to 26 

 29 to 137 



35 to 560 

 208 to 1058 



335 to 1300 

 613 to 1470 



70 to 589 

 123 to 1058 



9 to 85 

 9 to 260 



9 to 312 

 9 to 619 



29 to 109 

 29 to 114 



*Note: No information is available as to the stage of the tide at which the samples of water 

 for salinity tests were taken preceding July 20th. 



circulation of water around Sherman Island, thereby' expediting the up-river advance 

 of the bay water. 



The data in table 3 relating to the salinity of the upper bay and river waters 

 are derived from public records collected and compiled by the -State Water Commission. 



SUMMARY 



It appears from the foregoing that there are a number of factors to be considered 

 in any discussion of the salinity of the upper bay and lower river waters, particularly 

 when conditions in an\- year are to be compared with those in another, and, too, when 

 any forecast is attempted as to future conditions. 



Principal among these factors are the following: 



1. The seasonal water output of the Sacramento and San Joaquin Ri\ers, and 



