An Annapolis man died Saturday in the third accidental fatality of the past week in Maryland waters.

Christopher Thomas Cervasio, 18, disappeared Saturday while swimming in the Little Magothy River, the Maryland Natural Resources Police said. A search began, and his body was found about three hours later.

The Little Magothy, a Chesapeake Bay tributary, flows through Anne Arundel County, about half a dozen miles northeast of downtown Annapolis.

In a swimming death Tuesday, a man from Indian Head, Md., apparently drowned while in the water near Chapel Point State Park in Charles County, the natural resources authorities said.

He was identified as Robert Earl Claggett Jr., 27. Chapel Point is on the Port Tobacco River, a tributary of the Potomac River, and is about five miles southwest of La Plata.

In the week’s first incident, a man from the Annapolis area was fatally injured July 31 when he was thrown from a boat that struck a jetty.

The man, Paul Christopher Dettor, 49, was with two others on a 20-foot motorboat that hit the rock jetty about 11 p.m. at the entrance to Whitehall Creek, police said. Also a Chesapeake tributary, the creek is northeast of downtown Annapolis.

Dettor was thrown onto the rocks and died at a hospital.

The other two men on the boat had minor injuries, police said.