Working as part of Team Van Oord, Mackley is making good progress with a project to replace a weir on the River Medway at Tonbridge in Kent.
Bewley’s Weir fulfills many important functions including regulating the flow of the Medway to help manage flood risks, and ensuring a fresh drinking water supply for Tonbridge’s residents. It is also key to the efficient operation of the town’s sewage treatment plant works, and ensures a healthy level of water in the local rivers for ecological purposes.
An investigation into the condition of the weir earlier this year revealed the brickwork to be in poor condition and the foundations did not meet modern standards.
As a result, the Environment Agency appointed Team Van Oord to design and construct a new weir, and the plans were subsequently approved by Tonbridge and Malling Borough Council.
The project comprises the demolition and removal of the existing weir, followed by the construction of a U-shaped reinforced concrete weir structure, bed and wing walls. The walls of the new structure will be clad with brickwork to in order to meet requirements of the Conservation Area in which the weir is located.
Anti scour protection will be provided to the new structure adjacent to the River Medway, and to 10m of the right bank of the nearby Botany stream wall, which is located downstream of the weir itself.
The existing by pass culvert on left bank will be replaced with a new structure which will include a flow control gate in the access chamber, and a new eel pass will be installed across the weir.
An existing timber footbridge across Botany Stream, belonging to Kent County Council, will be removed prior to the works and then subsequently reinstated at the end of the project.
In order to carry out the work, the project team will dam off Botany Stream so the work can be carried out in the dry. The flow will be maintained by pumping water over the works to protect the environment and ensure the sewage works continue to function.
Work began on 22 September and the structural sections of the weir and wing walls will complete by Christmas 2014. It is estimated the project will be completed by the middle of March 2015.
9 December 2014