Denver Sluice was designed originally in 1651 to bar tidal water from the low fen areas and to improve navigation.
Denver lock is the main navigation structure linking the south Level River system to the tidal river and then to the middle level or the sea. The first sluice at Denver, constructed by the Dutch engineer Sir Cornelius Vermuyden in 1651, would have allowed navigation only when water levels each side of the sluice were equal. Unfortunately this first sluice and navigation lock collapsed in 1713 and it was not until 1730 that it was reconstructed by Labelye.
Its effective size was 11 metres long by 4 metres wide. It was replaced in 1834 by the existing lock when the Sluice was reconstructed to John Rennie`s design. The locks dimensions were increased to 23.5 metres by 5.5 metres wide. Two pairs of timber Vee doors pointing upstream and two pairs pointing downstream allowed navigation with high water either side of the lock.
Rennie`s structure (excluding doors) remains intact today. The latest work has been to replace the four pairs of Vee doors with two steel vertical lift gates. This has made the lock operation much simpler and has increased the lock`s effective length by 7 metres. The cill levels have been raised to give a minimum 2 metre draft and to enable the size of the gates to be reduced.
A main road passes over the sluice and the adjoining structures. Interpretation boards tell the full story and afterwards you can relax in the excellent restuarant and public house built for the boating community.
Downham Market, Norfolk
East of England