Unfortunately, whilst the works at Marple Lock 11 have been progressing steadily throughout the winter so far, they are a few weeks behind our original intended schedule.
It is now planned to re-open the canal to boats by close of play on Friday 24th May 2019. Delays have been encountered in the piling phase of the works, with the augering of the ground and reinforced concrete pile installation behind the existing lock walls proving slower than expected, as well as having to address some design changes due to site constraints. However, the piling is now complete, ensuring the ground is stable so that the failed lock walls can be carefully dismantled.
Given the progression of the works to date, at this stage we now have more certainty regarding the expected duration of the next phase; take-down of both lock walls, followed by their re-building back to the correct alignment. This is complex and time consuming, as the walls are being re-constructed like-for-like, in order to comply with heritage requirements. Lock 11 is a Grade II Listed structure.
We apologise for this ongoing closure, and are pushing forward to complete the re-construction of the lock as soon as possible.
Due to further movement of the chamber wall at Marple Lock 11, the lock is now too narrow for boats to fit through safely. As such, the Marple Lock Flight is unfortunately closed to navigation.
We have considered repeating the jacking operation to the lock walls to try and get a couple of additional weeks of navigation. However, we have dismissed this option as this would likely take around 2 weeks to complete and would coincide with the date the Marple and Bosley flights are closed to preserve water on the Upper Peak Forest and Macclesfield Canal sections.
We appreciate this is very frustrating for our customers and we are sorry for the inconvenience this causes. Our teams are busy planning the re-building of the lock walls and the flight will remain closed until this is complete.
The works to re-build the lock are currently anticipated to take place from November 2018 to March 2019. Given its depth and location, this is an extremely complex operation. Concrete retaining structures will be installed first on either side of the chamber, and the walls will then be carefully taken down to base level. They will then be re-built to the original alignment to reinstate suitable width to the lock, with the retaining structures behind providing the necessary ground support to prevent future movement of the reconstructed walls.
Thorough site investigation works have now been completed, including boreholes to confirm the ground conditions, trial pits to establish the location of the wall buttresses and coring of the lock walls themselves to identify their exact depth. All of this was necessary to be able to confirm a detailed design for the repair solution, the works for which are ongoing. Following this, the proposed repairs will have to go through a consent process with the lock being a Grade II listed structure and valued heritage asset, before the works on site will be able to commence.
We will provide more details in due course.