d. Ouring the spring acaths wes winds average 20 ots tron the easterortheast, the current action was vigorous, 0.5 mots in the aurfage and 0.3 in the bettoa currents. The eurrents set downwind ca the surface and roughly against it on the bettas. During the sumer ~wits lighter mre variable winds, the surface current sets dowwind still but auch mre slowly (less than 0.3 knots) and the bottoa current (0.1 mots) opposes it insofar as the geometry of the bottas of the lagoon permits. & sone of upwelling develops on the eastern edge of the uigecn and a einking sone predominates over a wide area on the west— ern side. o. The surface current (40 to 50 feet thiok) is free to nove in times of utherly wind inpulse when the surface current is setting with the wind Out the bottom current ia restrained somewhat and tends to align itealf with the major east-west axis of the lagoon. Thus even north-west o1 north-northwest wits eufficlent vigor to flow out to sea over the norihern reefs, the bottom current is turned only east~-south- east altering the more profound transport characteristics of the lagoon very little. For this reason, the sone of upwelling along the sastern rcofs is a permanent feature under all winds having an easterly component. 2. The sone of uswelling can be defined as the region of riseing water over witich the surface current is lose than § feet thick, in ahioh case it extends from the oorthurn tip of Slicind [sland to the southorn tip of Mnyu Ieland having a width of from 220 meters opposite Rolar Island te 3000 meters benind Bikini and Enayu Islands. The northerly setting commxcant is weak, joining the drift along the northern reefs which can be dotected as far west as Amen Island. The sontherly setting component is both stronger and acre veluminoas, flowing with a sean velocity of 9.3 mets southward to the Enyu Island eddy where it ia deflocted uprard by the sill at Enyu Channel under the inflowing cceanis water from the southeast. This geometry causue the two currcnts ta epiral horisontally in a combined westerly setting current oxtanding from surface to bottom which can be detested as far wost as Rukoji Chaanel. Tho path of this spirel is deflected by the tides inward on Lleed and osward at edd. g- From the above, it is apparent that contaminated areas will cFEe elongated east and weet. Due to settling of contamination and dif~ in the water, both horizontally and vertically, the bottan current: tend te spread out the elongated ares, throwing up contamination the eastern upwelling tone. Previous studies indicate an approxiaste 7 aay cyele of tarmmover in the lagoon. It has been determined tnat tne contagination at the end of one day will have buen reduced by currents and diffusion alone to the following: ‘festern sinking sone, 0.01% of original contamination; eastern upweiling sone, 1.0% of original contamination, with patches ep te LOX, 3. Without going inte great detail, and as a result of the scove discussions, the following conclusions are apparently acceptable to those directly conserned with ship and beat operation in the presence of radiological water contamination: ||