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C. E. LINDSAY 



submerged suction line and replacing it 

 with hot fresh water, we finally turned 

 to the use of a mechanical pipe cleaner 

 (Roto-rooter) which is used twice a year 

 to ream out the line. 



Three-quarter-inch flexible polyethylene 

 pipe used in part of the system also became 

 clogged with growing mussels. In time it 

 became impossible to remove these me- 

 chanically or by hot-water treatment. We 

 were forced to use concentrated hydro- 

 chloric acid in these lines to kill animals 

 and partially dissolve their shells. Recov- 

 ery of the hydrochloric acid has made this 

 type of cleaning economical, and thorough 

 flushing with sea water removed all traces 

 of acid. 



Shortly after the system was in opera- 

 tion, we found that the lower end of the 

 sea-water line was being heavily pounded 

 because of the sudden change in momen- 

 tum of the water when pumping was stop- 

 ped. A shock-absorbing effect was 

 achieved by attaching 4-foot vertical 4- 

 inch steel water pipes to the sea-water lines 

 both ahead of and behind the pump. This 

 cut down the water hammer, and no 

 further damage from this cause has oc- 

 curred. 



In 1957, additions to the sea-water sys- 

 tem were made which included wooden 

 storage tanks mentioned before, and 

 additional sea-water discharge lines to 

 carry water to control, mixing, and de- 

 livery tanks for a long-range sulfite waste 

 liquor bioassay. By this date, flexible 

 polyethylene and semirigid Kralastic 

 pipes and PVC fittings without plasti- 

 ciser were readily available, and had been 

 proven nontoxic in sea-water system use. 

 "We installed about 225 additional feet of 

 3-inch plastic sea-water line beyond the 

 main storage tank, to an elevation ap- 

 proximately 20 feet higher than the pre- 

 vious maximum water level. Kralastic 

 and PVC were joined with glue on the job 

 without special equipment. Modifications 



or correction of errors were made simply 

 by sawing the pipe off with a handsaw 

 and inserting the correction with slipover 

 couplings. This type of pipe has been im- 

 pervious to fractures, climatic extremes, 

 and cheinicals. 



The original water demand on the sea- 

 water system at the time of initial con- 

 struction ranged between 10,000 and 20,- 

 000 gallons of water per day. With in- 

 creased use and extension of the system, 

 demand increased to approximately 50,000 

 gallons per day. Throughout this period, 

 the WEFM hard-rubber-lined pump 

 originally described has been adequate to 

 provide all the water required and still 

 maintain intermittent pumping generally 

 in the tidal ranges desired. It is antici- 

 pated that in our location this system could 

 produce up to 100,000 gallons a day with- 

 out enlargement. 



We have found it essential to toxicity- 

 bioassay, by means of marine invertebrate 

 larvae, all of the component materials of 

 the sea-water system, determine their de- 

 gree of freedom from toxicity, and subse- 

 quently, bioassay quality of water supplied 

 to experimental animals. 



There are marked differences in growth, 

 survival, and fatness of oysters held in 

 the laboratory and those grown in the bay. 

 We have found that oysters suspended 

 near the surface do best, those grown on 

 tidelands are poorer, and those in the sea- 

 water storage tank are poorest. In each 

 instance the groups of oysters tested had 

 access to virtually unlimited quantities of 

 water. Hydrographic data collected just 

 beyond the intake shows stratification, 

 during the period of highest water pro- 

 ductivity, between surface waters and 

 those normally tapped by the sea-water 

 system. Chlorophyll values are also 

 higher in the bay surface water than at 

 either sea-water intake level or at point 

 of entry into laboratory aquariums. 

 These observations indicate that water 



