 In the early nineteenth century the engineer, William Jessop was engaged by the Bristol Dock Company to create a Floating Harbour to eliminate the problem of ships being grounded at low tide.Jessop built a lock to retain the water in the harbour; this was completed in 1809, and allowed ships to remain floating at all times, unaffected by the state of the tide on the river.Part of the project included building a dam at the Underfall Yard with a weir, known as the Overfall, to allow surplus river water to flow into the New Cut, an excavation which by-passed the Floating Harbour and joined the River Avon near Temple Meads.