Bristol's Floating Harbour is a historic impounded waterway — technically classified as a non-tidal, impounded basin — that runs through central Bristol, England. Engineered by William Jessop and constructed between 1804 and 1809 to address the city's extreme tidal range, the innovative project maintained a constant water level that allowed commercial ships to remain afloat regardless of the tide. To achieve this constant water level, the harbor operates as an enclosed, non-tidal system controlled by lock gates at both ends. When a vessel arrives from the sea via the tidal River Avon, it enters a lock chamber at the Cumberland Basin; the outer gates close behind it, and water from the harbor is gravitated into the chamber, raising the ship like an elevator until the water levels equalize and the inner gates can open. To ensure the harbor never drains or overflows, the man-made Feeder Canal continuously funnels fresh water into the basin from upstream, while the parallel New Cut bypass channel safely diverts the wild, fluctuating tides around the outside of the city center.

The harbor system runs from Brunel's South Entrance Lock, just west of the Plimsoll Swing Bridge, all the way east to Netham Lock at Netham Road. Its widest open sections sit directly on the north side of Spike Island along Baltic Wharf and St Augustine's Reach. The Floating Harbour Quay Wall and Bollards extending for about 900 meters along St Augustines Quay are themselves a Grade II English Listed structure. - AsNotedIn