The Problem
The affected property was a very large detached house in Keswick which had been subdivided into a series of houses whose back gardens backed onto a river. The gardens sloped steeply down towards the watercourse, which during storms in the early winter of 2015/16 had seen unprecedented water levels. During these storms, large rocks from further upstream had been conveyed by the river and had caused significant damage to the defences along this stretch. There was evidence of impact damage, water diversion and erosion. Optera were instructed by two of the occupants to investigate the damage to their properties and present the findings to their insurers. Following our report, we were instructed to repair a 60m stretch of the river.

The Optera Solution
The height of the defences along the full stretch of the watercourse was varied, but for this large property, there was a vertical drystone wall which had suffered impact damage, erosion and undermining from the diverted watercourse, which was buffeting the toe of the defence.

Consequently, Optera commissioned geotechnical and hydrological studies to determine the most appropriate form of repair and, in consultation with the Environment Agency and Natural England, we developed a scheme where the original drystone wall was repaired where possible but on sections where the damage was beyond repair, gabion baskets with rock revetments were installed to replace the original defence.

The project presented challenging working conditions as water levels can change rapidly according to the weather. A temporary wall was created to shield the working area from the river flow to allow our highly skilled team to progress with the works safely.

Project Conclusion
The works were completed two weeks ahead of schedule with thanks to some unseasonably mild weather and calm conditions. Sections of the original stone wall defence were successfully replaced with a gabion basket wall with rock revetment, while other sections were repaired and strengthened. The landscaping was completed and both customers were delighted with the outcome. Another successful project completed by Optera.

“The works were completed two weeks ahead of schedule … and both customers were delighted with the outcome. Another successful project completed by Optera.”

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