262 

 Water Temperature and Related Motion 



On the assumption that density currents can exist in 

 shallow water as well as in the open ocean, an attempt is 

 made to develop a qualitative method by which at least the 

 general patterns of flow can be derived from horizontal 

 temperature distributions in Santa Monica Bay. A general 

 correspendence existed between the drift of drogues and 

 the current directions deduced from the slopes of isothermal 

 surfaces. In general, the flow from thermal slopes was 

 toward the south during the winter period, and to the north 

 during the summer. This is correlated with the annual cycle 

 of wind conditions. 



Water Salinity and Nutrients 



The salinity of the water is essentially uniform (33.5 o/oo) 

 from a depth of 40 feet down to the approximate break in slope 

 (300 feet) at the outer edge of the shelf » In the surface 

 layer, above 40 feet, salinities almost never rise above 

 33,7 o/oo, and usually lie between 33.55 o/oo and 33.60 o/oo. 

 Salinities lower than 33.50 o/oo are found in the region of the 

 Hyperion outfall, Ballona Creek, and the mouths of small csmyons 

 leading from the Santa Monica Mountains, There is ho signifi- 

 cant seasonal variation in salinity. 



Average dilutions of effluent from the sxirface boil at. 

 Orange County and Hyperion range from 15 to 30 parts of sea 

 water to one part effluent. At Whites Point the average 

 dilution is 1;50. In the summer months, the limits of the 



