The Canals are a key feature of the Garden and our goal was to restore them to eliminate the leaks and regain some depth of water. The banks had been badly eroded over the years and saplings are growing in the mud. The dam stonework was in poor condition and the upper canal stone walls had collapsed.
The work started in 2013 with the opening of the sluice at the bottom of the canal, probably for the first time in over 50 years. The sluice runs out through culverts which had also collapsed over the years. Once the canal had drained down, the main debris was removed from the canal and an initial dredge carried out to allow for further inspection. The culvert runoffs were excavated, new pipes installed and new grills placed over the sluice.
Then the hard work, dredging the silt and reserving this to build the new banks. The new banks were formed using a geotextile membrane called Nicospan, fixed with posts every half metre and tied back by wire to stress posts to take the weight of the in-fill silt. The silt took a few months to dry out but now has allowed a new and stable bank to develop.
The completed canal banks have been faced with whaling boards to add strength but which will also allow vegetation to grow through the membrane and form a new natural bank.
The exercise was repeated on the middle and upper canals in 2014. Here the challenges were slightly different, the middle canal being in reasonable condition other than erosion by the dam and the upper dam in very poor condition.
The middle canal was dredged and partially ‘Nicospanned’ allowing a very natural bank to develop.
The upper canal was fully dredged and the supporting stone walls rebuilt. A new sluice was installed on the upper dam and extensive reclaying carried out.
Our thanks to Terraqua for their support and guidance over the use of Nicospan to retain the dredged silt for the new banks.
Our thanks to Grundon and especially those at Bishops Cleeve, for their support and advice on clay puddling. As part of the bank restoration we have had to rebuild the bank and re-puddle the lining.
The restoration work is being supported by the J.Paul Getty Jnr Charitable Trust, the Countryside Fund, the Cotswold Wardens and the Shipton Volunteers