Water Sealing
Challenge
Persistent leakage beneath a concrete slab at an SSSI reservoir required a solution that avoided major drawdown, environmental risk, cementitious grout, and complex approvals from Scottish environmental regulators.
Solution
Geobear injected expanding geopolymer through small drill holes, sealing the leak pathway instantly. Only minimal drawdown was required, making the method safe, fast, and environmentally compliant.
Water loss before geopolymer sealing
Only minimal water lowering required
Leaks stopped within minutes of final injection
Cobbinshaw Reservoir in West Lothian is a designated Site of Special Scientific Interest (SSSI) managed by Scottish Canals. For several years, the reservoir had suffered significant water leakage from the discharge chamber following the installation of three siphon pipes and control valves.
As the reservoir refilled, water began leaking through shutter holes in the discharge chamber walls and through joints beneath a 250 mm concrete slab. The leakage rate was estimated at 500 m³/day, posing operational and environmental challenges.
Scottish Canals attempted joint repairs, but the leakage persisted. The fault was eventually traced to the supporting wall beneath the slab, adjoining the old weir to the new siphon wall — a difficult and sensitive area to access.
A solution was required that avoided environmental harm, avoided lowering the reservoir significantly, and prevented long delays.
The Problem: Persistent leakage continued despite joint replacements and investigations. The source was hidden beneath a slab, making access difficult.
The Barrier: Traditional grouting required lowering the reservoir to –0.7 m, SEPA approval, dry-season timing, and risked contaminating an SSSI water body.
The Need: A fast, safe, low-impact sealing method that avoided environmental damage and did not require fully draining the reservoir.
Scottish Canals approached Geobear for a controlled, non-invasive water sealing method.
Minimal Drawdown: Only required the reservoir to be lowered to –0.3 m, maintaining environmental protection.
Small Diameter Injection: 12–16 mm drill holes through the slab allowed safe access without affecting structural integrity.
Targeted Treatment: Geopolymer was injected to 2 m below the slab, rising back up to fill voids and seal joints.
Precision Application: Material was injected at 0.5 m vertical increments along the supporting wall.
Instant Effect: The resin’s controlled expansion travelled through silty clay fill, sealing pathways and stopping the leak within minutes.
Despite unexpected bad weather, the lightweight Geobear setup allowed rapid adaptation and continued progress.
Leakage stopped immediately following the final injection phase.
Zero contamination risk: Geopolymer is inert and non-cementitious.
Full compliance with SSSI protections: No heavy plant, no concrete, no spoil, no risk to wildlife.
Minimal reservoir lowering: Avoided delays from SEPA seasonal restrictions.
Verified performance: Weekly statutory inspections report no recurrence of leakage to date.
This project demonstrated Geobear as the ideal solution for environmentally sensitive hydraulic structures.
Get in touch with our expert team today and discover how Geobear can extend the life of your critical infrastructure assets.
