Two views of the Swamp Locks from Tony Sampas. The Swamp Locks are on the Pawtucket Canal along Dutton Street, midway between the intersections with Fletcher and Broadway. Together with the Guard Locks further up Broadway and the Lower Locks outside the UMass Lowell Inn & Conference Center, the Swamp Locks allow boats to safely bypass a 32 foot drop in the Merrimack River over the course of a half mile.