Blunder Lock, spill weir and boundary markers

Summary

Canal lock and adjacent spill weir. Constructed c1777 for the Stroudwater Canal Company. Later alterations, and restored in the late C20.

Reasons for Designation

Blunder Lock, the adjacent spill weir and boundary markers are listed at Grade 2 for the following principal reasons:

* Intactness: despite restoration, the lock and the spill weir retain a good proportion of historic fabric
* Material: the lock pound is constructed entirely of stone, which is unusual since the majority of locks on this canal are of brick
* Functional relationship: the lock and the spill weir form a cogent and functionally-related group which demonstrates clearly how such structures operated together
* Group value: as a good group of contemporary canal structures which includes less common features such as the semi-circular spill weir and canalside boundary markers

History

The Stroudwater Navigation, built in 1775-9, was designed to link the River Severn at Framilode to Stroud, allowing coal to be brought from Shropshire, Staffordshire and the Forest of Dean to the textile mills of the Stroud valleys. The Thames and Severn Canal, constructed in 1783-9, was designed to run eastwards from Stroud, eventually linking the River Severn to the River Thames at Inglesham, near Lechlade. The Cotswold Canals, as they are also known, were generally successful, though the Thames and Severn in particular suffered serious technical failings which compromised its profitability; despite this, both canals continued in use well into the C20.

Blunder Lock which was formerly known as Lower Nassfield Lock was constructed c1777. It formed one of five locks along this section of the Stroudwater Navigation at Eastington and was designed to accommodate Severn trows. New gates were fitted to the lower entrance in 1882, and again in 1880. The ground paddles were removed in the 1960s and at the same time the culverts were sealed with concrete. The lock and the adjacent spill weir were restored in the 1990s.

Details

MATERIALS: The lock chamber is built of coursed limestone with ashlar dressings; the wing walls have been rebuilt in brick. The spill weir is constructed of stone and red brick.

DESCRIPTION: The single pound LOCK has stone-built walls and large ashlar coping stones, while the wing walls have been rebuilt in brick. There are limestone dressings at the gate positions to the upper and lower ends of the chamber. The pairs of timber gates were replaced in the late C20; iron fittings restrain the gateposts. The associated SPILL WEIR is situated on the towpath (north) side of the lock and formed part of the site's water management system: an overflow device for ensuring the canal water levels remained stable. It consists of an open roughly semi-circular, stone-lined trough into which the overspill flowed. The copings on the south side of the basin have been encased in concrete. The overflow channel leading underground from the weir has two shallow, segmental-arched openings in brick which spring from stone jambs and a central chamfered stone. The spill weir is enclosed by late-C20 iron railings.

SUBSIDIARY FEATURES: the group also includes two roughly-carved stone boundary markers. They are situated on the south side of the canal, at either end of the lock pound, and appear to date from the late C18.

Sources

Books and journals
Tucker, J, The Stroudwater Navigation, (2003), 91-2

End of official list entry

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