The National Park Service alerted us at 7 am on 11/27/2018, saying:
I apologize for the short notice. NPS will be removing vegetation from the Potomac Aqueduct today starting at 9:00 AM. It looks like the job of removing all vegetation from the faces of the Aqueduct will continue on throughout the week. Maintenance will be using a boom truck in order to remove the Ivy from the western face of the structure and any other hard to reach areas. NPS will have volunteer flaggers directing pedestrians and bicyclists through the work area. Barricades will be placed around the boom truck and signage will be placed at the trail head. Bicyclers are asked to dismount there bikes when in the work zone.
The Potomac Aqueduct is at the Georgetown end of the trail, over the gate between the trail and Water St.