Dunsan Curry , yD 2. Leccona) U Laren 1953 - The cireulation of Sicini Lagoon is doainantly wind driven. During the spring sonths wien winds average 20 incts free the east—nortneast the surrent astien is vigorous, 0.5 mots in the surface and 0.3 inthe bottom currents. The surrents set downwind on the surface and roughly against it on the bottem. The surface current is free to ave with the wind bat the bottom eurrent is restrained soaswhst and tends to align itself with the aajer east-west axis ef the lageon. The sone of up= welling along the esetern reefs is thus a permanent feature under al) winds having an easterly componect, It is prebebl. that the fully develeped surface current is produced within 1000 asters of the east reef but dees not obtain full development until the feteh is greater than 2200 meters. The tone of upwelling ean be defined ag the region of rising water over which the surface current ie loss than five feet thick, in whieh case it extends froa the northern tip of Bikini Island to the southern tis of yw Island, having @ width of from 2200 asters oppesite Rokar Island to 3000 meters bebind Slicini and Enya Ielands. The bettom current surfacing within this sone ia found to split into tws components at Bikini Island and flow parallel te the reef in cppesite dirostions. After Baker Day, Operations Creoesroads, the fleet was forsed to cov from ita anehoruge in the les of Enya [sland by the arrival of radio active water from the upwelling sone. The fleet took up positica soir the center of the aouth of Enyu channel where, dus te southurly winds, the surface layers were compoeed alacst entirely of cceanis mtars cad the radiocagtive water was by then so thoreughly cixed with large volumes of clean water that it no longer held any threat to the safety of the ships. Oceanis water flows into the lagoon continuously over the eastarn and nerthern roefs. The total volane of flew is about three parcont of the welume ef the lngoon per day. Coatinucus outflow occurs through the western part of nyu chonnel. disewhere, channels, passes, ind the weetern_ reef, the current reverses with the tide, As the oceanis ' water flows in, it is abeorded into the rotary cireulition of the ligoor thus gracuslly renewing the lagoon water,-wiile at the sce tice the Latter is being flushed out of the southwesturn passes at a rste of 302% per day. at this rato of flushing, any given mae of wator in the lagoon will, on the average, be redused to onemhalf its originil roluce in 22 days and to one t.ath its volume in two and a half oontns. 3. Radfonctivity In lagoon surfase detonations it is likely that radioactive srodust will be distributed from surface to bottoa with higher concentr-ticns 7@