organisms were consistently low in the coastal waters near the presently 

 operating Porapano and Delray outfalls. No noticeable fertilization effects 

 were found, and planktonic blooms with numbers greater than 500 per mil- 

 liliter were rare. A pile of sand and blackened organic material, about 

 3 feet high, 50 feet long and 30 feet wide was observed beneath the out- 

 fall. Only one species of pollution resistant worms survived here. In 

 the outer periphery of this pile, extending 100 feet north-south and 50 

 feet east-west a limited number of species were observed. 



Hydrographic investigations showed that coastal circulation and ex- 

 change processes were dominated by the Florida current. This was 

 attributed to the extreme narrowness of the Continental Shelf in this 

 area (1 to 1.5 nautical miles). Large fluctuations in the speed and 

 direction of the meandering western edge of the Florida current, travel- 

 ing northward through this coastal area, affected local circulation. 

 Resultant coastal currents were found to be flowing in a north-south 

 direction, with north currents predominating. Current reversals were 

 found to be associated with the cyclonic eddies of the Florida current. 

 These eddies appeared to behave as the major flushing mechanism masking 

 the effects of diurnal and semidiurnal tidal current fluctuations. The 

 residence time of the coastal water was estimated to be about 1 week. 



The spatial and temporal concentrations of sewage deposits were 

 determined by fluorometry and dye-tracing techniques. Predominance of 

 onshore winds were found to create surface sewage plumes, containing 

 high concentrations of coliform bacteria. 



5. Southern California 



a. Santa Monica Bay . Domestic and industrial waste waters from the 

 City of Los Angeles and 13 other cities are dumped in Santa Monica Bay. 

 These wastes receive different degrees of treatment by the Hyperion 

 Treatment Plant and are discharged into the Bay by pipeline outfalls. 

 The 1-mile effluent outfall has operated since 1949, the 7-mile digested 

 sludge outfall since September 1957, and the 5-mile outfall was placed 

 in service early in 1960. About 4,000 tons of solids per day are dis- 

 charged in the area. 



A study of sedimentation and dilution of digested sludge in Santa 

 Monica (Brooks, 1957) concluded that sludge accumulation rates should 

 average 2-3 inches per year within a 500-foot radius decreasing to 0.25 

 inch per year at a 2-mile radius from the outfall, assximing a constant 

 current of 0.2 knot with equal frequencies in all directions. These 

 rates of accumulation were considered unobjectionable based on 1956 

 standards . 



To assess the effects of the various discharges from the Hyperion 

 Treatment Plant since 1954, the City of Los Angeles has conducted and 

 supported extensive studies of the Bay. The results of observations 

 made through December 1959 have been summarized in papers by Hume et al, 

 (1962), by North (1962), and more recently by Hume and Graber (1966). 



21 



