Molesey Weir B

Molesey Weir B is part of the Molesey weir complex located upstream of Hampton Court Palace. The weir helps to control water levels between Teddington and Sunbury.

At present, Molesey Weir B uses old double-leaf buck gates (a vertical sliding gate).

There are two walkways that go across the structure. One walkway gives us access to the gates to operate the weir and the other allows residents of Ash Island to get to their homes and houseboats.

Work needed

Structural assessments have confirmed that we need to replace the weir structure completely. The weir is in poor condition, with significant corrosion. We also need to modernise the operating mechanism for the weir gates.

These refurbishment works will keep the weir in good working order, reduce future maintenance needs, and ensure the continued long-term use of the weir.

Our plans

• New gates: the current fifteen buck gates will be replaced with seven radial gates.
• Canopy: following consultation, the canopy will be replaced.
• Fish pass: the new weir will include an adjacent fish pass in place of the existing fish trap.
• Access to Ash Island: there will be a temporary bridge during construction work, which will give island residents and boat owners access to their properties.

What’s happening

We have successfully completed year one construction work at Molesey Weir B.  The operational handover of the four new radial gates happened on 20 December 2013.

We can only work on half of the weir at a time. Therefore, we will do year two construction work from March to November 2014.

We do not work during the winter months because we need to manage flood risk. We keep the weirs fully functional when there are higher flows. If there are high flows during the summer months (when we are on site) then we have plans to restore the full capacity of the weir.

Our main compound at Hurst Park will remain on site during the winter months even when we are not working. The temporary footbridge to Ash Island will remain open to the residents until year two construction is finished.

We will install a cofferdam (a temporary structure within the river made by putting in steel sheet piles) as part of year two construction work. The cofferdam will be closed off to create a dry and safe working area.

The installation of the sheet piles will start around the middle of March for approximately six weeks. This is before we begin dismantling and replacing the remaining weir structure and fish trap. The fish trap will be replaced with a new fish pass.

We will continue to update this webpage so that you can keep up to date with our works. We also have a whiteboard on site that will be updated on a weekly basis once the works start.