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
- Two-year 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 for approximately two years. 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 - December 2025
Phase one of works at the reservoir are now complete. We’ve successfully improved drawdown capacity of the reservoir which allows us to reduce the level of the reservoir quickly in the event of an emergency, and we have installed automated valves on the tower outlets to improve operational capabilities.
We have taken steps to make sure Scottish Water staff can safely get to the upstream side of the dam, and to fit equipment that safely measures the water flow.
Additional works completed include the scour valve protection enhancements at the foot of the spillway (reducing the potential for damage to the environment during operational activities), temporary grouting of the spillway, and reinforcement of areas across the north shore of the reservoir where erosion was evident.
Next Phase of Work
Diagram of tree felling and crane pad area for phase two
Next Steps
There will be limited activity over the winter period. During this time the site compound will be reduced until phase two can commence.
Phase two of the programme includes the refurbishment of the spillway. Enabling works ahead of this are expected to commence Spring 2026 which will include diversion of the Blackburn Raw Water Intake from the spillway which may require an over pumping arrangement, additional access created into the spillway, as well as widening of the current access.
This will require tree felling within the area circled yellow. We will organise replanting towards the end of the project and are working with our reservoir rangers to establish a biodiversity garden. Establishment of a crane pad is also required for the next phase.
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
