systems, being wind driven on the surface and roughly against the wind frea west to east on the bettom, The northern portion of the ENIWETOK Lagoon (as demonstrated en Operation IVY) appears to flush independently of the scuthern portion. At BIKINI, the entire lageon as 4a unit is involved in the flushing mechanism, BIKINI Lagoon flushing at a relatively mich slower rate than ENIWETOK. b, Considering the shot gehedule and the flushing mechanism cf the two lageons, the primary preblem of ship operation in such waters wis con- sidered real only at BIKINI. c. There existed a requirement that operations should be conducted in the lagoons without the inordinate delay between shots that would result from unrealistic contamination limits. d. No health hazard was anticipated as a result of reasonable Operations in the BIKINI LagechW. The problem was anticipated to be primarily an operational nuisance. 6. The ships expected to ba involved were the Weapons Ship, CVZ, LSD, LST's, AN, ATF's and small craft, f£. The Navy Task Group was directed to initiate studies to determine methods ef preventing concentration of activities in water evaporators, distribution lines and microorganic growths on the bettom of ships. in general, the prodlem of lagoon operation was 2s predicted except that the bulk of the transpert, was horisontal and downward. up-welling of radioactive material cecurred, Very little, if any, On all shots except FRAVO, ships were able te re-enter the NAN anchorages by approocimately H plus 6 to 10 hours, B plus l day, Fellowing BRAVO, ships were kept clear of the lagoon until Following YANKEE (the last shot at BIXINI) re-entry was delay-¢ (due to contamination at NAN Anchorage) until abow. H nlue 10 hours, 49 Upon