Overview

December 2024 Update

We completed this year's in-channel works in October - the construction of part of the walls to divide the two gates we are planning to install, upstream and downstream of the existing gate. The existing gate is still in place and operational over the winter. We have protected these partial walls to reduce the likelihood of debris building up on them this winter. We have also constructed parts of the new fish pass where they are adjacent to the new sections of wall.

Above: Parts of the new walls downstream of the existing gate including a section of the new fish pass

Above: Steel protection to the new downstream sections of wall to reduce the potential for debris build-up on them over the winter

After we finished this season's in-channel works, we have continued working on the banks of the sluice, in preparation for next summer's works to finish in-channel and install new gates. The works on the banks have included extension of the control building so it can house the control systems for the new gates, installing ducts for new control and power cables around the site, installing a new valve on a bypass pipe to allow fine-tuning of very low summer river flows and installing grasscrete surfacing to avoid damage by future works.

Above: Extending the control building (left) and its finished size (right)

Above: New cable ducts (left) and New valve and chamber in the bypass pipe to fine-tune very low summer flows (right)

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. Two gates will give finer control of water levels and allow one gate to be maintained while the other is still operational.

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)