Island Barn Reservoir – Embankment Leakage remedial works

Island Barn Reservoir is a non-impounding reservoir retained by an earthfill embankment that has a history of leakage. Thames Water has undertaken a Portfolio Risk Assessment identifying seepage at the reservoir as a priority remedial work activity. A Willowstick^® geophysical leakage detection survey was undertaken at the reservoir and three areas of leakage were identified through the embankment and foundation. Atkins was commissioned, as part of the Eight2O alliance, to design the remedial works required to seal the leakages. As result an impermeable barrier made of steel sheet piles was assessed to be the optimal solution to form a contiguous cut-off wall to reduce the leakage.

This paper describes how the leak was identified and remedial works proposed and undertaken. In particular, the conclusion of the feasibility study played a crucial role for the development of the remedial works planning along with the site space restrictions and associated waste disposal requirements. This paper examines all the stages of the project’s development, from site survey to the remedial works design and construction. This project demonstrates how remedial works can be carried out without affecting the integrity and stability of embankments whilst achieving sound results.