Hardmead Sluice Replacement Project Information Page

Closes 1 Jul 2024

Opened 25 Jun 2021


Updated: 29 June 2022

Hardmead Sluice Replacement Project Information Page

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.

Hardmead Sluice is a major flood control structure within the LFRC and is located at Great Amwell, close to the town of Ware in Hertfordshire. As well as managing flood risk, the sluice is needed to balance the requirement to send flow down the River Lee Amwell Magna Loop and sustain water levels in the River Lee Navigation.

What we are doing

We are replacing and improving the gates and operating equipment at Hardmead Sluice as the existing ones are now reaching the end of their 50 year working life.

A failure of Hardmead Sluice would result in increased flood risk and loss of control of upstream water levels.

Replacing the sluice gates and their operating equipment will maintain the conveyance of storm flood flows through the structure to sustain the current level of flood management and to maintain the ability to control upstream water levels for navigation, water supply, amenity and environmental needs. 

Improving the environment

The existing sluice acts as a barrier to the free passage of fish and eels.  As part of this project a new fish and eel pass is being constructed to enable the free passage of fish around the sluice. 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 this impact you?

The main works will be commencing in July 2022 and are expected to be completed by spring 2024. During the main works you may notice additional temporary noise and vibrations. Construction vehicles will be entering the site from Hollycross Lane via the private access road and across Amwell Bridge. Public Rights of Way will not be impacted but there will be a minor diversion for pedestrians at the northern extent of the site boundary. Road closures should not be required.

If you would like any further detail about any of the above information please get in touch at PSO-HNL@environment-agency.gov.uk

Thank you for visiting our project information page.

If you would like any further detail about any of the above information please get in touch at PSO-HNL@environment-agency.gov.uk


  • Anyone from any background


  • Flood management