Because of Aberdeen Proving Ground (APG) surrounding the Bush River many times the River is closed in different areas to allow testing of weapons systems. During that time Patrol Boats will approach you and move you if you are in the area to be closed.
This happens most often between Monday and Friday, however it can happen at any time. I am posting the RANGE OPERATIONS PHONE NUMBER so you can call in advance to find the status of the Firing Range prior to your trip........that number is.........410-278-3971/2256.
If you wish to research more information on APG use the web link: http://www.apg.army.mil/apghome/sites/local/