The kayaker who died after falling out of his boat in the Potomac River on Sunday has been identified as 22-year-old William Lankford from Lynchburg, Virginia. Three kayakers were navigating down the Potomac near Great Falls when Lankford suddenly became separated from the group on May 3. The two other kayakers later found him struggling in the rapids, according to the Maryland Department of Natural Resources. The two men rescued Lankford from t…