20 
the shelf water column to approach isothermal conditions. However, 
in the Hyperion area the surface water is warmed not only by solar 
radiation, but also by the large heat contribution from the man- 
made sources on shore. Thus, the warmer surface layer tends to 
remain separated from the normal subsurface layer by a moderate 
to slight gradient or thermocline. Away from the shore and from 
the warm-water wedge of artificial origin this minor thermocline 
becomes less marked and finally disappears. 
Summary 
At none of the outfalls does the thermocline or thermal 
gradient materially affect the initial rising turbulent effluent 
column. The degree of mixing of the various columns is marked 
thermally in all of the areas by inversions and complex temperature 
gradients. The Whites Point area has weaker temperature gradients 
due to the better mixing of the effluent with the sea water. 
After the initial rise of the effluent column the formation 
of surface zones of high nutrients and dilution is common to all 
outfalls, except at Whites Point where the salinity change is 
slight. At the same time a turbid lower layer forms as the 
result of sedimentation from the effluent colum. The presence 
of thermal boundaries in the water of sufficient density difference 
may cause the turbid layer to lie above them. The suppression of 
these thermal boundaries in the winter months is followed by a 
marked decline of the turbid layer at higher levels in the water 
column. 
WATER MOTION IN SANTA MONICA BAY 
From the data presently available, a generalized description 
of water motion in Santa Monica Bay can be developed. Ocean 
