Summary
A circular spill-weir, of the well-fall type, probably dating from the 1770s.
Reasons for Designation
The circular spill weir at Holly Tree Garden, built in the 1770s as an overflow weir for the Stroudwater Navigation, is designated at Grade II, for the following principal reasons:
Technological interest: as a relatively rare circular spill-weir of a type which is uncommon nationally
Historic interest: as it helps to describe the functioning of the C18 Stroudwater Navigation
Group value: with the other similar spill-weir some 130m to the east
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.
This spill-weir was probably constructed in the 1770s, as part of the development of the Stroudwater Navigation; it is situated on the southern bank of the canal. It is of the well-fall type, with overspill water from the canal pushing up the outer, circular trough, then spilling down the central cylinder, from where it was culverted into the nearby River Frome via a drain running north-south.
Details
The weir is constructed from brick and ashlar limestone. It has an outer trough with a central, ashlar-lined cylinder, atop which is an iron band, part of the original levelling ring.
