29 April 1953 —L2E DRANDUL FOR RICORD SUBJECT: Ship and Bost Operation in Radiologically Contaminated Lagoons A 1. Over a period of the last 24 months, considerable discussion has been given to the possibility of radiological contamination ceing trapped im an atoll lagoon te such an extent ap to hasper Naval act:vities and thereby indirectly cause delays in the operation. These dise cussions involved representatives ef JTF SE7EN (Lt Col House, Cdr Hall), TG 7.2 (Dr. iraves, Dr. Ogle, Iir. Curry, Major Servis), 1G 7.3 (LtCder Carlson, Lt Gill), Buled (Capt Tipton, LtCdr Etter), BuShips (Cdr Hoff- man, LtCdr Coates), Op=36 (Capt “alker), WRUL (Dr. Theapson), APSUP (Capt Maynard, Or. Scoville, Lt Col itDennel), Serippe Institute of Oceanography (Dr. Revell), aad University >of “ushington. 2. For the purpose of this record, the followkng dessription of the Bikini and Eniwetok lagoon cireulctions is prosented (condonsad frea reperte on scveral onm-eite and model studies of the Alidat ligcon cade in connest.on with Operation CROSSROADS, and from experience with mi- wotek on Operation IVY).” a. Both lagoons aro essontially "boltedrive" syatems, currents driven with the wind on thy surface and roughly sgcinst tho wind on the bottom. Upwelling scones appoar in the easturn l.goon wmters and sinking sconce in the westorn portions. bottom currents tend to rensin aligned with oast-west axce, roughly independent of the dirsction of the wind. b. The rate of Mlushing of the Bilcini ligcon ie such that it is nearly a closed bagin insofar ae the inturval Ostwen CASTLE snot dates is coccerned, requiring 22 days to change half of the water and 75 days to change 90%. The orimary flushing route is through Eayu Cusnanel, The scuth-weetern passes account for 4 considerable but Lesser amount of eaptying. Very little, or name, of the emptying takes place over the northern and eastern reefs. @. The Eniwetok lagoon flushing system is auch sore rapid, and has two asjer routes, i.e. through the eastern and weatern reefs for the northern lagoon waters and through Deep and Wide Entrances for southern waters. As demonstrated on IVY, contaainaticoa in the northern waters was flushed out without getting into the southern portion. For this reason, and considering the shot echedule, all that folicwe below ie applicable only to Biiini lagoon operations. Incl 3} to TAB "Fr F-12