Watching Brief

Date 16 November 2007 - 14 January 2008

Event ID 577276

Category Recording

Type Watching Brief

Permalink http://canmore.org.uk/event/577276

NS 7961 7876 – NS 7913 7871 A photographic survey of the N wall of the Forth and Clyde Canal was undertaken

in advance of the installation of by-wash culverts to help regulate water flow in the locks. The installation of these culverts involved a reduction in sections of the canal wall to the E and W of the locks as well as the excavation of deep trenches into which the concrete chambers for the culverts could be set. A large pipe set in a deep trench then joined these chambers. These ground-breaking works were monitored as part of a watching brief. The photographic survey of the N canal bank was limited to the stretch between Locks 18 and 19 and the short sections of wall to the W of 19 and E of 18 that were to be affected by the installation of the culverts. A further survey was carried out on the S face of Lock 19 to record the different phases of build and repair within. Work was undertaken from 16 November 2007–14 January 2008.

The work has shown that an apparently simple structure can be complex. By looking at both the original construction and the ways in which people have attempted over time to stem the erosive actions acting on the walls and structure of the canal, we can see that practical and financial considerations were being taken into account through the various phases of repair and rebuild.

The original construction involved puddling the canal base with clay, footing a masonry wall on the N bank and sealing the rear of the wall with an impervious skin of puddle clay. Sand and boulders could then be built up

behind the wall and the rising puddle base. In this way there was enough weight behind the wall to hold back the water and sealant to prevent leakage. However, over time breaching, slippage, inundation and erosion took their toll and leaks appeared. Some solutions may seem relatively short-term (such as small sections of wooden shoring) but they were thought to be worth the effort and must have had some kind of positive effect. Two trenches skirted behind Locks 18 and 19, and it seems that a similar but much tighter and better quality masonry construction was again backed by puddling with clay. Sand and boulders, presumably with a puddle clay liner below, also fill the area behind this.

Archive: RCAHMS (intended)

Funder: British Waterways Scotland

Paul Fox (Kirkdale Archaeology), 2008

OASIS Id: kirkdale1-60124