It is the policy of the State to foster water safety for recreational uses of the Potomac River, including swimming, bathing, wading, diving, tubing, rafting, and other uses involving contact with the water. There is a particular need to restrict the recreational use of certain waters known to be hazardous to personal safety some or all of the time, specifically, that section of the Potomac River beginning at the District of Columbia and Maryland boundary line which crosses the Potomac River approximately one-half mile north of Chain Bridge and continuing upstream to a line across the Potomac River at Edwards Ferry Road.