Designing the Floating Harbour
In 1765, the first proposal for creating a non-tidal harbour was put forward by the eminent engineer John Smeaton (Smeaton is better known as the designer of the Eddystone lighthouse, but also built a number of canals). There followed a number of different ideas, but no progress was made until the 1790s, when a new round of plans was tabled.
In 1802 William Jessop, a famous civil engineer, was engaged to come up with a scheme. Jessop had been born in Plymouth in 1745 and was apprenticed to Smeaton. During this time he learned a lot about canal building that led to a successful career in his own right later. He carried out extensive waterways work on the river Trent, the river Severn and the river Thames, and created the Grand Junction Canal in the Midlands and the West India Docks in London. He died in 1814.
Jessop’s final scheme was an amalgamation of the best ideas from numerous earlier proposals.
A weir at Netham controlled the level of the Harbour water, channelling water along a Feeder Canal and allowing excess to spill back into the tidal river Avon.
A second weir, the Overfall Dam, at Rownham controlled the level at the outward end of the Harbour.
A new half-tidal basin (Cumberland Basin) was constructed with entrance locks from the river and a junction lock into the Harbour. These locks catered for larger vessels.
The New Cut was dug from Rownham to Totterdown, creating a tidal bypass on which smaller vessels could proceed further inland to secondary entrances at Bathurst Basin and Totterdown, bringing them closer to the quays that they wished to visit. This was the idea of the Reverend William Milton, vicar of Temple church.