144 



DONALD K. JOICE AND DEMOREST DAVENPORT 



STORAOE 

 AND HEAD TANK 

 ELEV. 39.0 



:^ OVERFLOW 

 TO STORM DRAIN 



■*©-l 



CENTRIFUGAL 

 PUMP 

 ELEV. 20.0 



Fl LTER BOX CUT-AWAY 



SEA WATER 

 INTAKE LINEJ 



JET PUMP 

 ELEV. 9.0 



4 FT. 



BEACH SAND 



FIGURE 1. — Piping diagram and cut-away view of filter box in sea-water system of the Marine 

 Laboratory of the University of California, Santa Barbara, Calif. 



beach sand covering, ranging in depth 

 from 18 inches to approximately 48 inches, 

 depending on the season, augments the 

 integral filter media of the unit. The area 

 over the filter is covered with water for all 

 but a few of the lowest tides of the year. 

 The unit is connected to the shore installa- 

 tions by a 4-inch asbestos-cement pipe suc- 

 tion line which is also buried and concreted 

 in the beach floor shale, to protect it 

 against tidal action. 



The size of the filter unit was determined 

 by a number of factors, all of which were 

 strongly influenced by economic consider- 

 ations. The prefabricated unit, with 48 

 square feet of filter area, was designed to 

 provide the 30 gallons per minute required 

 for a small marine laboratory. Weighing 

 approximately 10 tons, it was of a size and 

 shape that could be readily hoisted on and 

 off a truck or trailer. 



The total beach installation was com- 

 pleted in 1 day between a high and low 

 tide. As the high tide began to recede, 

 bulldozers followed it out, clearing the 3 

 feet of sand from the strip which was to 



be trenched for the pipe installation. As 

 the bulldozers left the shore they were fol- 

 lowed by the survey crew, who set grade 

 stakes and were in turn followed by the 

 trenching machine. The pipe-laying crew, 

 assisted by portable pumps to remove seep- 

 age from the trench, came only a few yards 

 behind. As soon as four or five lengths of 

 pipe had been installed and fixed in place, 

 transit-mix cement trucks poured concrete 

 over the line. In preparation tlie bull- 

 dozers pushed the sand into revetments 

 along the course of tlie project. These 

 revetments, which averaged about 8 feet 

 high, enclosed the total work site on the 

 ocean side and served as a cofferdam to 

 hold back the incoming tide late in the 

 afternoon. This gave the construction 

 crew an additional 4 hours of time which 

 the tides would not have otherwise per- 

 mitted. 



A depression approximately 36 inches 

 deep was bulldozed out for the filter loca- 

 tion, and the filter was lowered into place. 

 It was then fitted with a reinforced-rubber 

 suction hose, the flexibility of which al- 



