The Trews Weir rebuild rose from about £7m to £12m, so Exeter City Council has cut it back to a repair. Works planned for 2026 have no new start date.
Exeter City Council has scaled back its plan to rebuild Trews Weir after the cost rose from about £7 million to £12 million. The council said on 21 October that it is now drawing up a narrower scheme to repair, stabilise and strengthen the existing weir.
The weir holds up the water in Exeter Canal and at the Quay. The council’s own engineers have warned it is close to the end of its life.
Why the cost went up
Cllr Ruth Williams, the council’s deputy leader and lead councillor for city management, said technical and environmental problems had emerged with the original design.
“For various reasons, the cost of the original scheme increased from around £7 million to £12 million and even with grant funding from the Environment Agency, we didn’t have the funding to cover this significant increase,” she said.
“Instead, we undertook a fundamental review of the scheme and developed a revised approach focused on repairing, stabilising and strengthening the existing weir. Our engineers have been working on these plans throughout the year.”
The council describes the new scheme as “narrower in scope” but “practical, deliverable and affordable”. It says the change also avoids flood risk and delivery problems found during detailed design.
What was planned, and when
The original plan was set out to the Exeter Harbour Board in December 2025. It included:
- rebuilding much of the weir with sheet piles and a new watertight concrete surface
- extending the weir downstream to remove the drop at its foot
- a longer, two-flight fish pass for salmon and trout
- a new eel pass on the eastern side
- a canoe and kayak portage in place of the old fish pass
That presentation gave the first phase as May to September 2026 and the second as April to September 2027. It also said Haven Banks 2 and 3 car park would be the main works compound.
The release this week gives no new start date. It says the council will consult the public “once proposals have reached an appropriate level of detail”.
Why the weir matters
Trews Weir sits about 500 metres downstream of Exeter Quay. It was first built in the 17th century to keep water in the canal. The December presentation set out the problem plainly:
- St James Weir, further downstream, collapsed in early 2019 and water below Trews Weir dropped by about 1.5 metres
- that exposed a damaged surface that had been under water, and water is flowing through the weir’s core
- a 2024 condition review put its remaining life at one to five years
If it failed, the council said, the canal would stop working and the Quay walls could be destabilised. It also warned that high voltage cables on the riverbed that supply the city centre could be damaged. The council has a legal duty under the 1829 Exeter Canal Act to keep the canal navigable from the estuary to the Quay.
What happens to the fish
The fish pass was the most ambitious part of the old plan. The River Exe is an important salmon river, and the Environment Agency rates its salmon population “probably at risk”.
The council now says the existing fish pass was built by the Environment Agency, and that it will “support the Environment Agency with any fish pass improvements it wishes to make”. The revised scheme does include two smaller measures:
- removing an existing low wall on the weir
- changing the bypass channel to steer fish towards the existing pass
What it means for you
- Canal and Quay users: nothing changes yet. There are no works on site and no closures have been announced.
- Haven Banks drivers and walkers: the old plan used Haven Banks 2 and 3 car park as a compound and closed part of the riverside road on weekdays. Whether the new scheme needs the same is not yet known. Our parking guide lists the city’s car parks.
- Anyone who wants a say: the council has promised public engagement as the detailed design develops. We will report when it opens.
The council has not yet published a revised cost or timetable. This page will be updated when it does.
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