Weir Today, Gone Tomorrow

The trunk sewer is approximately 30km long and runs through the River Lee Valley on its journey from Stevenage to Rye Meads Sewage Treatment Works. Installed in 1951, the 1.5m diameter pipe carries sewage waste from over 80,000 households and businesses in Stevenage, Welwyn Garden City, Hatfield, Hertford and surrounding towns and villages and as such is an extremely important piece of infrastructure.

The existing weir was constructed in 1977 to maintain the water level in an otherwise dry reach of the Lee between the Hertford Basin and the River Beane. However, the flow of water over the weir has accelerated erosion of the riverbed around the sewer.

In works lasting approximately three months contractors J Breheny Contractors Ltd will break the old weir into manageable pieces, some of which will be recycled on site. A replacement weir will be constructed immediately downstream of the sewer, which will be protected beneath a gravel bed. Environment Agency engineers have taken the opportunity to replace the existing ugly concrete structure. Instead, a more unobtrusive two-step granite structure will incorporate two-metre-wide passes, allowing fish migration and an improved facility for local canoeists.

Environment Agency project manager Brian Rochford said:

“Without replacing this weir, the sewer is in real danger of being undermined. This work will safeguard the environment as well as improving fish migration and a local canoe facility.

“It is the duty of the Environment Agency to protect and enhance facilities which support water-related sport and recreation. This project maintains safe use of the weir and, once complete, we hope the replacement weir will be enjoyed by water users from all backgrounds for many years to come.

Darren Fergus, chairman of Herts Canoe Club said:

“Sitting next to the River Lee, Herts Canoe Club is ideally situated for local canoeists who enjoy paddling this stretch of river. Hundreds of canoeists have learned to paddle here and Hartham weir is often one of their first thrills on the water. Hartham weir is a safe water feature that has given local kayakers a taste of moving water and spurred many of them on to kayak down some of the best white water in the UK and abroad.

“Improving Hartham weir and protecting the local environment is something Herts Canoe Club fully supports. Canoeing is all about enjoying the environment around us and this project will enhance our paddling experience and make this popular water feature even better for local canoeists.”

The immediate area surrounding the weir will be closed to canoeists during the construction period, although canoeists and anglers can still use the river up and downstream of the works and footpaths in the area will remain open, with some minor local diversions.

For more information on the project please contact Brian Rochford on 01707 632342.