What century were the Leiper Canal and Duluth Ship Canal built?
Duluth Ship Canal The Duluth Ship Canal is an artificial channel cut through Minnesota Point, providing direct access to Duluth harbor from Lake Superior. Begun privately in 1871, it was put under federal supervision and maintenance several years later. It is still an important component of the harbor facilities.
North Shore Channel The North Shore Channel is a drainage canal built between 1907 and 1910 to flush the sewage-filled North Branch of the Chicago River down the Chicago Sanitary and Ship Canal. The sewage carrying duty has been largely taken over by the Chicago Deep Tunnel, but there are still occasional discharges due to heavy rains.