REPUBLICAN CITY, Neb.,— The U.S. Army Corps of Engineers at Harlan County Lake is preparing for a closure of the dam to allow the contractor, OCCI, to continue work on the dam spillway. During the periods of May 20 and 21 and May 27 through June 4, both lanes of the dam may be closed from 6 a.m. to 6 p.m. daily and traffic will be directed to take the designated detour.