6 March 2024

Written by

Chris Howes

Denver Sluice and Lock on the Great Ouse are owned and managed by the Environment Agency (EA). Salter’s Lode Sluice and Lock are owned and managed by the Middle Level Commissioners. Transit between Denver Sluice and Salter’s Lode allows access to the Great Ouse, the river Cam, and the rivers Lark, Little Ouse, and Wissey. The Denver crossing is now effectively closed and the only navigable connection between the Great Ouse and the rest of the ‘system’ is by the difficult and hazardous Wash crossing (until the Bedford / Milton Keynes link progresses).

After Christmas 2023, the Middle Level Commissioners (MLC) dredged Salter’s Lode lock. This necessitated removing over 250 tons of silt from inside the lock. There is a considerable build up of silt outside the lock, on the tidal Great Ouse managed by the EA. MLC are concerned that as soon as they open the tidal doors of Salter’s Lode it will immediately be filled with silt from the tidal Great Ouse, and so they have closed the lock until the EA dredge outside it.

At a recent meeting of its Anglian Water Group (AWG), EA reported this to stakeholders, but currently the EA has no plans to dredge! The link between the Great Ouse and the Middle Level now appears indefinitely closed until one or other of the navigation authorities gives in. This closes off approximately 130 miles of navigation, affects hundreds of leisure boats and prevents access from the connected navigable system to places such as Bedford and Cambridge.

During April 2023, contractors for EA dredged outside Denver (photo 1 below). Rather than removing arisings, they threw it back out into river (in the hope it would wash out to sea), and there was subsequently heavy siltation experienced downstream at the first bend in the river (photos 2 and 3 below). This blocked the outfall of the Old Bedford River and caused several hire boat groundings on the tidal side of Salter’s Lode. It appears that MLC feel that EA caused this sudden and dramatic increase in rate of siltation affecting Salter’s Lode, and are waiting for EA to do something about it on ‘their side’.

Sue O’Hare, IWA deputy national chair, said “We are appalled that boaters are left stranded through no fault of their own, and that businesses are left to count their losses because of the Environment Agency’s inaction.  We sympathise with the Middle Level Commissioners’ wish to keep their lock clear of silt and functioning correctly for its dual purposes of navigation and flood protection for local communities, and we sympathise with the Environment Agency at having to deal with over double the usual monthly rainfall in this area so far this year, but the Agency has a legal duty to keep the waterway open for navigation.

A Spokesperson for the Environment Agency said: “We have been and will continue to progress plans for the clearance of the blockages caused by the build-up of silt in the tidal river at Denver Lock and Salters Lode within the scope of our available budget.”

There have been delays across all our navigation works programme as a direct result of the weather and subsequent river conditions. We will continue to work with our delivery partners to resolve the situation as soon as we can. Updates will be provided on our navigation notices which can be found at our Visit Anglian Waterways webpages.”

[The title photo shows silting at Salters Lode in early March 2024 – by Paul Burrows of the Middle Level Commissioners]

Dredging by the Environment Agency in April 2023 – by Chris Howes

Subsequent heavy siltation experienced downstream at the first bend in the river – by Chris Howes

Siltation being cleared – by Chris Howes