Overview

August 2024 Update

In April we improved the trackway to Stanstead Sluice beside the river so that it can withstand the expected size and volume of construction traffic during the two-year construction programme.

The temporary construction compound has been established near the sluice for our contractor's staff offices, equipment and materials storage. This has a temporary solar panel array to reduce the amount of electricity generators needed on site.

Above: Construction compound near Stanstead Sluice with its temporary solar panel array

We have improved the trackways around the sluice and compound to minimise damaging the ground.

Above: Improved tracks around Stanstead Sluice and the construction compound

After another very wet winter and spring, resulting in higher than normal groundwater and river flows for the time of year, we have been delayed in starting the works in the sluice itself. We have adapted our temporary working plans to increase the capacity of pumps to carry river water around the sluice while we are working within it. These pumps now have the capacity to cope with the river flows we have been experiencing during this unusual summer. They will be in place until the autumn when we will return the existing sluice gate into operation to manage the much higher winter river flows.

Above: Temporary pump pipework to carry the summer river flows around Stanstead Sluice

With the arrival of drier weather and increase in temporary pumping capacity we have been able to start works within the sluice itself. After isolating the sluice with stoplogs and pumping out the water, we are constructing parts of the walls to divide the two new gates and support the fish pass. This will allow the existing sluice gate to operate as normal over the winter, which is required as there isn't enough time to carry out all the new gate installation work in one summer and have them working ahead of the following winter.

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: The current Stanstead Sluice

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)