The speed of the personal watercraft shall be regulated so as to avoid the risk of damage or injury by any means, from the personal watercraft wake, to all manner of craft whether floating, moored, anchored or underway, or to piers, wharfs, bulkheads, draw spans or other waterfront construction, either directly or by the effect of the wash or wave raised by such personal watercraft through its speed or otherwise. Personal watercraft shall not be operated in any lagoon, canal or confined area of less than 200 feet in width at any speed above low speed or "no wake" speed, or above an idle speed within 50 feet of a bathing beach that has its boundaries marked by buoys or signs, the shoreline, or any person in the water.