Aberchalder Spillway

Aberchalder - Spillway – centred on NH 33998 03813

This spillway is set into the north embankment of the canal 250m to the north of the swing bridge NH30SW 9.00. The spillway comprises a paved platform 15m in width by 69m in length. On its east side a slope of pitched cobbles 0.5m in height drops to the canal water level and on the west side a faced stone slope 3m height in height drops to the level of the river. The spillway is generally 2.5m below the level of the embankment and is edged by a stone wall of 1m height.

Visited by Scottish Canals Recording Project (MM), 25 June 2013

NH 33994 03832 Cullochy Weir, which forms part of the Caledonian Canal, was breached by unusually high water levels. The water surge washed away c10m of the weir, the weir’s stone pitching protection facing the River Oich and 35m of northern embankment. As a result, Scottish Canals

had to undertake emergency works to repair the weir.

A watching brief was undertaken, 26–27 March 2015, during these works to record the surviving remains. On arrival, emergency works had already commenced but it was clear that the entire NW side and NE end of the weir

had been washed away. This had exposed a longitudinal and transverse section through the weir structure, the transverse section was only through the surviving SE half of the weir. The emergency works has also exposed a section through the canal bank at the SW end of the weir where the weir connected with the bank.

Where the weir connected with the canal bank the remains of mortared stone revetting walls were present. The canal bank was built from river derived pebbles/cobbles and gravel capped with a more soil rich deposit and turf.

The weir survived to a height of 1.6–1.7m. It was simply constructed: it had a concrete and irregular stone slab surface and the main body of the weir structure was made from river derived pebbles/cobbles and gravel like the canal bank. This appeared to have been built directly over the natural which

was of similar material. A deposit of grey clay was identified in the centre of the weir structure. This was the full depth of the main body of the weir and may have been a clay core to prevent water penetrating through the weir structure itself. Where the actual weir structure had been completely

removed wooden posts were identified at regular intervals along the SE side of the weir. These may have formed some sort of shuttering or shoring during the weir’s construction.

Archive: NRHE (intended). Report: Highland HER and NRHE

Funder: Scottish Canals

Bruce Glendinning – CFA Archaeology Ltd

(Source: DES, Volume 17)