Without them, there wouldn’t be water for navigation or wildlife along our canals, or for those who enjoy the reservoirs themselves for sailing, fishing and other recreational activities.
We are carrying out a significant programme of investment in these reservoirs to make sure they stay resilient to climate change and comply with the strict legislation that applies to all large reservoirs. Over the past two years we have spent £52 million on reservoir works (a large proportion of the overall maintenance spend our charity has available), with spend forecast to average above £13 million per year on the reservoirs alone for the next five years.
Short-term challenges for long term benefit
The nature of the work required means that we have to reduce (‘draw down’) the water level in the reservoirs until the work is complete, meaning there may be less water available to feed navigation. This means that we are more reliant on rain throughout the year, especially in summer when the canals are busier, to keep water levels topped up.
During 2026 we have significant construction works planned at over nine reservoirs. Six of these feed well-used canals and drawing down the water for the works will mean there will be less water available. Impact will be minimised as far as possible and where feasible we schedule drawdown works towards the end of the summer.
While we do everything to ensure the navigations remain open, our legal obligations around reservoir safety and managing flood risk must take priority. We apologise for any inconvenience this causes boaters.
In 2026, the following reservoir works may affect navigation:
Leeds & Liverpool Canal
Major works to replace and enlarge the spillway at Rishton Reservoir are now complete and the reservoir is back in service for 2026: there will be a smaller drawdown, currently planned for 2027, for the second phase of work at Rishton. Slipper Hill, Foulridge Lower and Foulridge Upper reservoirs were drawn down for investigations in 2025 which are now complete. Works are planned at all three reservoirs over the next three years in sequence, provisionally: Slipper Hill 2026; Foulridge Upper 2027; Foulridge Lower 2028. While this means there will be an impact on the available capacity of the reservoirs to feed the canals, it is reduced, and there is more water available for the whole canal than during the 2025 season. The summit reservoir group will have comparable supplies available for much of the season but with reduced availability in the summer months: this is expected to be in line with expected reservoir usage. To help ensure the water that is available lasts as long as possible, we may start the peak boating season with restricted opening hours in place at certain lock flights.
More information about boating on the Leeds & Liverpool here.
Huddersfield Narrow and Rochdale canals
Major works to enlarge the spillway at Slaithwaite Reservoir commenced in November 2025 and will continue throughout all of 2026, significantly reducing the amount of water available for the eastern part of the Huddersfield Narrow. The works at Diggle Reservoir have been deferred to 2028 which will reduce the impact on the canal: these works are to move a drawoff valve that is currently situated 30m deep within the dam. Diggle feeds the canal summit so will support the temporary loss of Slaithwaite Reservoir. Access, drawoff and spillway improvements continue at Black Moss, March Haigh & Swellands reservoirs, but these works will not impact canal feed.
More information about boating on the Huddersfield Narrow here.
More information about boating on the Rochdale here.
Peak Forest and Macclesfield canals
The work to reinstate the water supply from Toddbrook Reservoir has impacted the Peak Forest and Macclesfield. The works are due to be substantially completed by March 2026 enabling Toddbrook re-fill to commence, with water available for canal supply. Combs Reservoir will be drawn down late in 2026 for investigation works, with minimal additional impact expected. There is a substantial drawdown of Combs Reservoir planned for 2027: this will be timed to be late in the boating season with little impact on supply.
More information about boating on the Peak Forest here.
More information about boating on the Macclesfield here.
Other reservoir works that are not expected to affect navigation:
Birmingham Canal Navigations: The clay core at Olton Reservoir has settled over time and is being raised to reinstate safe impounding levels. The drawdown has taken longer than planned and there may be a small impact to canal supply. The investigations at Rotton Park Reservoir in 2025 were positive, reducing the amount of works expected, with smaller scale works now planned in 2028.
Grand Union: Works are substantially complete at Wilstone Reservoir to install a 1km-long sheet piled wall through the full depth of the embankment to reduce leakage. The reservoir has been re-filled and is available for supply. Sulby and Welford reservoirs are now re-filled following initial works. They are available for the 2026 season but will be drawn down in late 2027 to enable spillway enlargement at Welford into 2028.
Shropshire Union: Grouting masonry weirs to reduce leakage at Calf Heath Reservoir, Gailey Upper and Gailey Lower reservoirs will be completed by March 2026 enabling them to be filled and available for the 2026 season. These reservoirs have been held down for a number of years and will now provide a full supply.
Lancaster Canal: Works are planned for 2027 to improve the drawdown facilities at the reservoir and may require a substantial drawdown. Investigations are planned through 2026. Both activities will be planned around the boating season and impact on the canal is not anticipated.
Please check our notices and stoppages page for further details of how these works may affect cruising, and to see where water-saving restrictions are in place.
