Investing in Gladhouse Reservoir
Project Overview
Gladhouse Reservoir is a drinking water source to 150,000 customers in Midlothian and parts of Edinburgh. To keep it running smoothly, we need to carry out maintenance and upgrades.
We are currently working on a multi-million-pound improvement project to keep the site safe and reliable.
Most of the construction work will take place on the north shore of the reservoir, where the spillway will undergo a major refurbishment.
The works are being carried out by Scottish Water’s delivery partner, George Leslie Ltd.
At A Glance
- Provides drinking water to 150,000 customers
- Multi-million-pound investment
- Road closure from June 2025
- No alternative walkway during road closure
- Phase one complete, phase two from Spring 2026
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Expected completion Summer 2027
Gladhouse Reservoir Investment Project
Satellite view of the planned work at Gladhouse Reservoir, Midlothian
What We Are Doing
We are currently carrying out a major refurbishment of the spillway channel, including replacing and raising the road bridge to accommodate shifting weather patterns leading to flood events.
The spillway is a controlled overflow channel that directs excess water from a reservoir to prevent flooding and protect the dam structure, especially during heavy rainfall or storms.
The planned improvements ensure Scottish Water complies with the Reservoirs (Scotland) Act 2011. The work addresses specific safety measures known as Measures in the Interest of Safety (MIOS).
Before work can commence on the spillway, the road bridge has been removed as instructed by All-Reservoir Panel Engineers (ARPE) and in consideration of the health and safety risk to the teams operating underneath it.
This means that a road closure will be in place from June 2025 on the north shore of the reservoir. The diversion route will be via Temple Village.
Other refurbishment work will include strengthening joints, improving flood defences, and installing temporary valves to help control water levels.
Phase 1 Complete
Drone Tour of Spillway and Infrastructure
Latest Update - October 2026
Phase 1 of works at the reservoir are complete, which allowed us to successfully deliver key MIOS items 1 to 4.
- Improved drawdown capacity of the reservoir. This allows us to reduce the level of the reservoir quickly in the event of an emergency.
- Installation of automated valves on the tower outlets to improve operational capabilities.
- Measures to provide safe access to the upstream face of the dam for Scottish Water staff.
- Installation of apparatus to safely gauge the flow at the outlet of the tower culvert.
Next Steps
Before the end of March 2027, work will recommence at the Blackburn Raw Water Intake, to rebuild the retaining wall structure, replace the penstock and complete final channel clearance works.
Phase 2 of the programme is the refurbishment of the Spillway and is currently forecast to commence Spring 2027. Early works will include but are not limited to;
- Permanent diversion of the Blackburn Raw Water Intake from the spillway. This may require an over pumping arrangement.
- Establishment of a crane pad.
Tree felling was carried out within the area highlighted, earlier in the year, to allow an additional access into the spillway as well of widening of the current access. Replanting of these areas will be carried out towards the end of the project. The road bridge will be replaced once this work is complete.
Tree Felling
Diagram of the area that had tree felling and where the crane pad will go in phase two
Visiting Gladhouse During Construction
We recognise our reservoirs provide important access to green space, and Gladhouse reservoir is enjoyed and valued for many reasons by those who visit.
Visiting is still permitted while our work takes place, however; there are several restrictions in place to be mindful of. As always, we'll do all we can to keep any disruption to a minimum.
Traffic management for the road closure will be in place for the duration of our project; we have teams scheduled to inspect and manage this on a regular basis. There is no alternative walkway via the road bridge during the road closure.
Further Information
We will continue to update this page with the latest information.
Need to get in touch? You can email us at gladhousereservoir@scottishwater.co.uk. You can also follow us on social media to keep up-to-date on our activities:
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Facebook: Scottish Water
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Instagram: ScottishWater
