Mereway Weir Replacement

Closes 17 Jul 2020

Opened 17 Jul 2019


Updated on: 20 February 2020

Welcome to the Mereway project information webpage. Please click the link below to FAQs at the bottom of the page.


What is currently happening?

We are currently fixing the new weir in place. These works began in November 2019, with completion expected at the end of March. The previous weir has been removed and stop logs have been placed to create a dry working area. River flows will be maintained by a bypass channel that exists in the bank. With the option to install pumps and remove stoplogs when there are larger flows coming down the River Crane. The picture below shows the new weir being lifted into the River Crane channel at Mereway.

Local roads may be busier than usual whilst larger vehicles access the site.You may see our construction consultants around Mereway Nature Reserve area as the works develop.

Future works

Construction of the fish pass through Mereway Nature Reserve is still being confirmed and hopes to start construction once a suitable option has been agreed.


We are currently replacing the existing weir on the River Crane located at the end of Mereway Road. Please see the location on the map below. The weir is coming to the end of its 30 year lifespan and it and its mechanisms have to be replaced.

Above: Location of Mereway Weir and picture of the previous structure

Alongside the weir replacement, we are also hoping to construct a fish pass, connecting the Duke of Northumberland's River and the River Crane. This will allow fish to access parts of the River Crane that have previously been limited or not available. This will attract further wildlife and create greater biodiversity in the surrounding areas. We are currently reviewing the possible designs. Please see potential locations below.

Above: Fish pass outline design in colour

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We are currently altering the above fish pass design due to high costs and projected impacts to the park. We will update this page with the latest designs as they are developed.

Who have we involved in our planning?

  • Richmond Borough Council
  • Friends of the River Crane (FORCE)
  • Friends of Kneller Gardens
  • Crane Valley Partnership


What is Mereway Weir? Mereway Weir is an automatic tilting weir on the River Crane, designed to maintain flows for the Duke of Northumberland's River and the River Crane.

What does it do? It keeps a steady flow into the River Crane and into the Duke of Northumberland and is a key flood defence asset for the Twickenham area.

Why is it being replaced? It is now at the end of its lifespan, including the parts that operate it. A new weir and operating systems are required to make sure it keeps working as normal.

What happens if flows down the Crane are higher? Pumps will be activated to increase the amount of water down the River Crane, and if needed stop logs will be removed to increase this flow. This will mirror the usual process taken by the automated weir during the works period.

How will we be notified about this? A pre-emtive flood alert will be issued for the Fluvial River Crane if rainfalls expected will cause higher flows. The interim between activing pumps and removal of stop logs will cause a short period of time where levels of the Duke of Northumberland will be higher, but they will recede quickly.

Who are the Environment Agency working with? We are working with Richmond Borough Council, Friends of the River Crane, Crane Valley Partnership and Friends of Kneller Gardens.

Why is a fish pass needed? A fish pass will be beneficial as the weir currently acts as a barrier to migrating fish from the Crane and Duke of Northumberland.

How will this benefit me? The weir currently protects over 500 residential properties from a high risk flood event. Updating the current weir will continue this protection. The fish pass will act as another channel, linking the Duke of Northumberland and the River Crane through Mereway Nature Reserve. The pathways will be preserved as well as further pathways next to the new channel.

Will I still be able to walk through Mereway Nature Reserve during the works? Yes, walking routes will still be accessible with diversion signs in place.

Will I still be able to drive through during the works? Yes, if there are any restrictions, these will be hours at a time rather than full days.

What trees will be removed? Some trees in the fish pass footprint may have to be removed.

How will we be notified about the works? Information will be available on this webpage so please check every so often. Other forms of communication are also planned:

  • Update letter drops for surrounding residents
  • Further posters around Mereway Nature Reserve
  • Social media

Contact Us

If you have a question about the project or would like further detail please email below:

Other Useful Links

Visit our website here to find out more about what you can do to reduce the impact of flooding on you and your property.

Sign up to flood warnings here.

Find out about your rights and responsibilities of owning a watercourse here.

If you have been flooded from a public sewer, please complete Thames Water's sewer flooding questionnaire on their website here and return it to them at the address on the form. 


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