Derwent Reservoir – Erosion Protection with AquaRockBag® in Derbyshire, UK

The Challenge

A significant scour hole—about 4–5 meters deep and 210 m³ in volume—was discovered at the Ashop inlet of Derwent Reservoir. It had begun to undermine the adjacent concrete structure. With limited working space, public access nearby, and an operational reservoir that couldn’t be drained, the site presented complex engineering and logistical challenges.

The Solution

To address the erosion, the project team deployed AquaRockBag® alongside a newly constructed gabion basket wall. These units could be pre-filled and placed precisely, making them ideal for the constrained site. Over 450 tonnes of material were installed, including new rock and concrete works, to reinforce the structure. The design was environmentally sensitive and relied on local contractors and materials.

The Outcome

The repair successfully stabilized the area with minimal disruption and long-term durability. AquaRockBag® proved to be a flexible and effective solution, particularly under tough site conditions. The work, timed during the summer low-water period, allowed safe access and a smooth return to normal reservoir operation once complete.