2 . 5 Dye Tracer Study 



Dye dilution studies are based on the principle that the 

 downstream dilution of a conservative substance is directly 

 proportional to the mixing characteristics of the receiving 

 water body. Temperature is assumed to be conservative in 

 this study in that the temperature of the thermal plume is 

 reduced only through mixing with Long Island Sound water. 

 Dilution of Rhodamine WT dye injected into the thermal plume 

 therefore is assumed to directly mimic the temperature 

 reduction of the plume. 



2.5.1 Dye Injection 



Rhodamine WT dye is a fluorescent, biodegradable tracer that 

 is extremely soluble in water and detectable in very small 

 concentrations (less than 0.05 parts per billion). The dye 

 was supplied as a 20 percent solution by Crompton and Knowles 

 Corporation, Gibralter, Pennsylvania. The specific gravity 

 of the individual lot of Rhodamine WT which OSI used at 

 Mi 1 1 stone was 1.112 at 8 0° F. 



Dye was injected into the circulation water discharge well of 

 Unit 3 utilizing a Fluid Metering, Inc. laboratory pump. The 

 20% solution of dye was pumped onto the surface of the 

 discharge water. Mixing occured where the Unit 3 water 

 entered the quarry and again where the waters from Units 1, 

 2, and 3 meet in the middle of the quarry. Dye injection 

 began at 1500 hours on 23 August initially at a rate of 5 

 pounds per hour and was increased to 7 pounds per hour at 

 approximately 1700 hours on 24 August 1987. Dye injection 

 rates were monitored by weighing the dye supply reservoir at 

 approximately one-hour intervals to an accuracy of j-0.01 

 pounds. A specification sheet for the Fluid Metering, Inc. 

 pump is included in Appendix I. 



