Overview

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August 2025 Update

We have removed the old sluice gate and a redundant section of the channel bed and installed a new section of channel bed, secured by ground anchors, into the underlying ground. The sluice bed has been lowered to ensure the new gates have the same flood capacity as the previous gate, while allowing for a fish pass to be included within the channel width.

Above: Breaking out the redundant section of channel bed

Above: Installing ground anchors to secure a replacement section of channel bed

The new section of channel bed has been cast with concrete allowing us to proceed with preparing and building the middle wall that will separate the two new gates.

Above: The steel reinforcing bars being placed for the middle wall to separate two new sluice gates.

Above: Ducts to allow air behind the new gates and smooth the flow of water over them.

Above: One of the float chambers from the old sluice structure that is no longer required.

Above: An overview of the works showing the new wall in the sluice and a temporary large flume pipe to carry river flows through the works site

Project Background

The waterways in the Lower Lee valley include the River Lee Navigation, Old River Lea, and the Lee Flood Relief Channel (LFRC). The LFRC was built between 1949 and 1977 and is designed to carry flood water to reduce the likelihood of flooding in the Lower Lee valley. A system of weirs, gates and sluices control water levels in the LFRC. These maintain water levels for water supply, navigation, amenity and environmental purposes while allowing flood flows to pass during storm events.

Stanstead Sluice is a major flood control structure within the LFRC and is located close to the villages of Stanstead Abbotts and St Margarets. It directly reduces the flood risk to 83 properties and contributes benefitting many more as part of the LFRC system. As well as managing flood risk the sluice maintains water levels in the River Lee Navigation.

Above: Stanstead Sluice before works began

What we are doing

We are replacing the sluice gate and improving the operating equipment at Stanstead Sluice as the existing ones are now reaching the end of their working life after over 45 years of service. A failure of Stanstead Sluice would result in increased flood risk and loss of control of upstream water levels. The existing single sluice gate will be replaced with two narrower gates.

These improvements will maintain the conveyance of storm flood flows through the structure, sustain the current level of flood management and maintain the ability to control upstream water levels for navigation, water supply, amenity and environmental needs.

The existing sluice is a barrier to the free passage of fish and eels migrating up the river. As part of this project, new fish and eel passes will be constructed to enable the free passage of fish and eels around the sluice and up to Hardmead Sluice where more fish and eel passes have already been installed. This will help increase the length of watercourses these species can migrate along, extending their range and improving the aquatic biodiversity of the watercourses.

How will the works affect me?

During the works, you may notice additional temporary construction noise during the working week.

Construction vehicles will enter the site using the access track from Hollycross Road, and then along the riverside trackway towards Stanstead Sluice. Unrestricted access will be required at all times.

We recognise that the trackway is well used by the public. We have limited the speed of construction traffic appropriately to enable continued quiet recreational use of the path and presence of the adjacent nature reserve.

Public Rights of Way will not be impacted.

Location of Stanstead Sluice and our access route (purple dotted line)