Exception. The provisions of this regulation do not apply to professional skin or scuba divers: Engaged in demolition, salvage, construction, rescue, or repair work during the regular course of business; and Who are registered with the Lake manager. Skin and scuba diving is permitted in all areas of the Lake except: Restricted areas which are: Above the dam, and Around the intake tower; Heavily traveled boat lanes; Narrow channels; and Areas where visibility is obscured. Diver Down Flag. A person may not skin or scuba dive in waters of the Lake unless the diving area is marked by one diver down flag displayed at all times while a diver is in the water. Flag Requirements. A flag shall: Have a red field with a diagonal stripe not less than 1-1/2 inches wide running upper left to lower right; Have dimensions not less than 10 inches x 10 inches; Have the top visible at least 3 feet above the surface of the water; Be anchored and affixed to a separate flotation device; Have no attachment to any vessel or navigational device; and Have placement that avoids and does not obstruct boat traffic. A diver shall surface within 100 feet of the diver down flag marking that diver's area.