Like 1969 bleachers tickets at Wrigley Field, residents won’t be able to simply wake up any day and on an impromptu basis decide to make a splash. They’ll have to reserve, no more than five days in advance, one of four daily two-hour time slots at Oriole Pool. Normally in business on Memorial Day, the pool will not open until June 5 to allow for outdoor training of staff, as pools at local schools will not be available for training.