Jackson has completed work for the Environment Agency to build up and stabilise ground next to a major weir on the River Avon.
The river island connected to Pershore Weir in Worcestershire had badly eroded following flooding events in November 2019 and February 2020.
Jackson came up with a solution to build up the island. On the area closest to the weir the team installed reno mattresses – large, flat gabion-style mesh and wood frames filled with rock – and then covered the surface with new top soil to encourage vegetation to take hold.
The team also rebuilt the concrete apron around the island, which had become overgrown with vegetation, and was cracked and damaged, and installed rock rolls to prevent erosion. An existing fish pass was cleaned out and some of the joints were re-grouted.
Because of the location of the works, transportation of equipment and materials to site presented a logistical challenge.
All materials and plant used on the project had to be delivered to site via tug boat and barges, which were supplied to Jackson by the Avon Navigation Trust. Even the skips and waste material had to be removed by boat. This required careful planning to ensure deliveries were timed with boat availability and the works programme, so no time was lost.
Health and safety
A well-known landmark in the area, Pershore Weir has one of the largest weir drops on the River Avon at six metres. The water flows fast at this point and a two-man safety boat was present throughout the project as an emergency measure.
The Jackson team on the island also had to work around a number of trees planted as a memorial garden and to take care they were not disturbed. Since completion of the works, vegetation has established on site – the plant roots providing extra stability to the affected ground.
Consultant works manager Steve Hunter said: “Logistics were a particular challenge on this project but through close collaboration we finished within the timeframe. Our solution will minimise erosion and ensure this important water structure will remain secure for many years to come.”