At Hey Lock

Walkers wishing to travel along the Sankey Canal between Bradley Lock and Newton Brook will need waterproof footwear and hard hats over the next few weeks. Collapses of the bank beneath this well-used towpath have given rise to a serious risk to walkers anglers and cyclists, and St.Helens MBC is funding the necessary repair work.

Contractors began by driving piles into the canal bed about a metre out from the bank and closing off the two ends to form a long narrow coffer dam. Water was then pumped out and the collapse revealed. The section of canal between Bradley Lock and Newton Brook was "restored" in the late 1970s but it now seems that it was more of a cosmetic job than a proper restoration.

Today’s workers were astonished to find that there are no stone or concrete foundations to the canal walls but that they are simply built up on a clay base. This is not necessarily a problem as a similar set up has been found on other sections of the canal and the walls have survived intact. In fact this part of Merseyside was thickly overlain by glacial deposits after the last ice age and it would have been difficult to dig down far enough to reach bedrock. The clay would have been of sufficient load bearing capacity to take the weight of the walls and as a bonus was waterproof, thus eliminating the need for large quantities of puddled clay in any alternative method of construction.

The contractors were also interested to find that railway sleepers had been laid directly onto the clay surface, supported by vertical stakes at intervals, topped off by a layer of coping stones ( paving slabs from the streets of St.Helens) then back-filled with loose black cindery materials. Superficially the towpath looks strong and secure but in practice once the vertical stakes rotted away the pressure of the infill forced the sleepers outwards into the canal and the copings above them have collapsed.

Good solid concrete foundations are now being installed and a solid stone wall built up to towpath level, producing an excellent result, matching the original but now a solid durable job. The works being undertaken at present will deal only with the short stretches of the canal which have either collapsed or appear to be in imminent danger of doing so, leaving the remaining lengths still liable to collapse at some time in the future. A total rebuild of the whole section is required to leave the canal strong enough for another couple of hundred years service. This, however, would be costly, and would need to be funded by major capital grants. This is, of course, exactly what SCARS is seeking to obtain, through the implementation of the Atkins Feasibility Report into the Sankey’s restoration.

As this damage to the towpath could not have been foreseen during the Borough’s budget preparation process, St.Helens MBC is to be commended for finding the means to finance the work from its revenue funding.

Leakage at Tanhouse Lane

Boat owners at Spike Island and Fiddlers Ferry have been a little worried of late since the level of the Sankey Canal went down by about a foot (30cms to the moderns ) The drop shows up very clearly all along the waterline where stonework has been exposed.

The cause of the problem can be found at Carterhouse Bridge where Tanhouse Lane meets the railway and canal in Widnes. Below the turning circle for the bridge, which is on the inland side of the canal, the ground has fallen away to leave a void down to about 12 feet ( see conversion charts for metric equivalent) here the water can be seen cascading down through the canal walls before disappearing off into the darkness, presumably below the canal and out into the Mersey although no discharge can be seen from the towpath. A large culvert which passes along Tanhouse Lane and below the railway has also collapsed but at present is carrying no load.

Part way down the hole the remains of a substantial timber framework can be seen as if intended to support the base of the turning circle and leave room for the culvert below. In fact it may well be this chamber which has collapsed. The hole in the canal wall is unlikely to enlarge, but what damage is being done below the canal is anyone’s guess. Although Halton BC is aware of the problem it has been unable to commence repair work at present.