12 December 2025 

Reservoir safety projects completed at Cringle and Clypse

Manx Utilities has completed two major reservoir safety projects that strengthen dam resilience and support a reliable water supply for the Island.  The Cringle Spillway Refurbishment finished on 8 December, and the Clypse Reservoir Valve Replacement is complete with the reservoir now refilling under close operational monitoring.

Cringle Spillway Refurbishment

The Cringle scheme delivered a new concrete spillway channel, replaced an aging raw water main, and cleared the stilling pond downstream of the spillway.  Delivered under budget and with enhanced quality and safety measures incorporated during final stages.  Protected orchids and fungi present on site were preserved in line with ecological best practice and oversight.  The site remained open to the public throughout.

The upgrade mitigates the risk that the 80‑year‑old stone masonry spillway could be undermined during heavy rainfall—a failure that could lead to dam erosion or subsidence. The improvement therefore safeguards communities and properties along the Silverburn River as far as Castletown Harbour.

In keeping with Cringle’s character, the project retained and reinstated the distinctive white quartz stone that capped the original spillway walls.  The preserved quartz has been placed behind the new walls where required, linking the new structure with the site’s heritage.

The main works are complete, and the reservoir overspilled on 2 December for the first time since February.  The site will remain fenced temporarily to allow grass to establish and for minor weather-dependent finishing touches to be carried out safely.  During this period, the water level will be held approximately 1 metre down to maintain safe access.

Clypse Reservoir Valve Replacement

Manx Utilities has replaced two critical valves at Clypse Reservoir: one that transfers water to Kerrowdhoo and another that allows controlled drainage.  While the reservoir was drawn down for these works, a new pressure sensor was installed to provide real-time water level data to Manx Utilities’ control system.

With the engineering works complete, refilling has begun.  The level will be raised gradually over a controlled period, with the process closely monitored by Manx Utilities’ Operations Team.  The project was completed on time and on budget.

To protect the reservoir banks, Manx Utilities will carry out targeted ground maintenance along the western bank, including the removal of willows and gorse whose roots can damage embankments.  Advance notices will be displayed on site ahead of this work, planned for early in the New Year.

Manx Utilities worked closely with DEFA throughout these projects to ensure environmental best practice.  While draining Clypse was essential for safety, mitigation measures were taken to minimise ecological impact as far as possible.  Fish reintroduction will occur once water levels stabilise, under DEFA Fisheries guidance, to restore a healthy habitat.