Cumberland Basin walls and associated features including Junction Lock swing bridge, Bristol, City of Bristol

Summary

The stone walls to the basin and locks at the west end of Bristol's Floating Harbour (except to Brunel’s Lock, which is separately listed at Grade II*). The listing includes mooring bollards, capstans, the lock gates and slipway to Howard’s Lock and the swing bridge to Junction Lock. The first phase is of 1803-1809, with a second major phase of work in the 1860-1870s.

Description

Quay and lock walls of 1803-1809 by William Jessop, Chief Engineer of the Bristol Dock Company, and C19 bollards. Altered 1863-1873 by Thomas Howard and with later alterations including a swing bridge across Junction Lock of 1925 by John Lysaght Ltd.

MATERIALS: the quay and lock walls are constructed of dressed pennant blocks with granite and limestone coping stones. The C19 mooring bollards and capstans that line the sides of the Cumberland Basin and its associated locks (both functioning and defunct) are of cast iron. The swing bridge over Junction Lock is steel and the lock gates to Howard’s North Entrance Lock have steel paddles.

DESCRIPTION: Cumberland Basin is a narrow oval on plan, roughly on an east-west orientation, with Junction Lock at the north-east corner opening into the Floating Harbour and the North Entrance Lock (Howard’s Lock) at the north-west corner to the River Avon. Jessop's former South Junction Lock is to the south-east corner and is used for mooring. Bridges cross the junction locks: a swing bridge across Junction Lock of 1925 built by John Lysaght Ltd and erected by William Cowlin and Son (plate on east arch); and a fixed road bridge to the south across Jessop’s Lock has steel railings and the underside is sealed with large dressed stone blocks to create the marina on the harbour side. Howard’s Lock has pedestrian access across the two lock gates, which retain early to mid C20 fabric; the former Brunel swing bridge (separately listed at Grade II*) being disused and standing on the southern edge of the lock. On the north side of Howard’s Lock is a raised platform providing access to Cumberland Basin Road with latching posts formerly used to fix the swing bridge into position.

Mooring bollards are positioned around the basin and locks. Those along the north side of Howard’s Lock terminate at a cobbled slipway to the River Avon. There are also a number of historic capstans beside the locations of lock gates and former lock gates, including on the peninsular of land to the south side of Howard’s Lock where there is also the sealed mouth of the former north entrance lock. A metal ladder is fixed to the southern edge of this former lock, where it adjoins Brunel’s Lock (separately Grade II*).
To the north-east corner of the basin chamber are three flights of stone steps. Other notable features include a C19 capstan near the south-east corner of Jessop's Lock and a former steel and timber ‘gridiron’ structure attached outside the entrance to the former north entrance lock.

History

Bristol’s Floating Harbour was designed and built in the early C19 to improve the function of the City’s port, and thereby its competitiveness in international trade. Access to the port was hampered by the extreme tidal range of the River Avon and by the mid-C18 Bristol was superseded by Liverpool as the principal English port linked to the transatlantic slave trade. In 1802, after much delay, the City’s merchants finally agreed a scheme to dam and bypass the river to create a floating harbour of around 70 acres that could function irrespective of the height of tide. Ships would enter an open area of water called Cumberland Basin via one of two locks at Rownham and pass into the harbour via another lock at Hotwells. The River Avon was diverted into a ‘New Cut’ on a route to the south of the City.

William Jessop designed the scheme and was employed as Chief Engineer under the newly formed Bristol Dock Company (BDC); work started in 1803 following Parliamentary approval. The works were completed in 1809 and the basin and Floating Harbour opened soon afterwards. They are shown on Plumley and Ashmead’s 1828 map with two adjacent entrance locks between the river and Cumberland Basin and a single ‘junction’ lock (Jessop’s Lock) to the Floating Harbour in the east. The Floating Harbour reputedly provided Bristol with the largest area of impounded water for shipping in the world and the two entrance locks into the Cumberland Basin from the River Avon were the largest structures of their kind yet built.

BDC maintained the harbour until 1848 when the company was closed and responsibility passed to a new Docks Committee of the Bristol Corporation. BDC had overseen changes to the structures including the insertion of four culverts with sluices to the overfall dam to designs of 1832 by I K Brunel. This created an underfall dam that allowed large quantities of silt to be scoured out of the harbour to flow into the New Cut. Brunel also proposed changes to the entrance locks, which had fallen into disrepair and could no longer accommodate the increasing size of steamships. The length and width of the South Entrance Lock (Brunel’s Lock, Grade II*) was increased and opened in 1849. The new lock with bridges across both entrance locks is shown on Ashmead’s Map of 1855, and Champion’s Dock to the east is marked as Floating Dock.

Proposals made by Thomas Howard (Docks Engineer) in 1864 to create new locks that would give better shipping access were prompted by the harbour struggling against competition from Avonmouth Docks. The scheme would comprise new larger locks from both the river to the basin (North Entrance Lock, also known as Howard’s Lock), and from the basin to the harbour (Junction Lock), and with swing bridges for road traffic. The tender to construct Junction Lock was won by William Tredwell in October 1866 and the lock was opened in September 1871. The harbour end of the lock truncated the entrance to the Floating/ Merchant’s Dock. At the other end of the basin, Howard’s Lock was begun in 1868 and opened in July 1873. It included a new extension to the river quay wall with an inclined cattle landing slip and a floating steamboat landing stage. The new lock chamber was orientated further north-east to ease the approach from the river and the construction resulted in the loss of the dock at Rownham Wharf, the displacement of the Rownham Ferry and the demolition of a row of houses and a coal depot.

The new arrangement of locks is shown on Ashmead’s Map of 1874. Around this time, the swing bridge across the south entrance lock (Brunel’s Lock, Grade II*) was moved, shortened and installed on Howard’s Lock. In 1875-1876, a replica in steel was installed over Brunel’s lock. The new lock gates were hydraulically operated and powered from the engine house by Junction Lock (The Pump House PH, Grade II), and, later, by a new power station at Underfall Yard. From 1907, the pumps were powered by the substation in Avon Crescent (Grade II).

By the First Edition Ordnance Survey Map of 1886 the Brunel’s Lock had been taken out of use and a dam and sluices installed. The map shows a number of new buildings and structures including transit sheds and cattle pens had been built around the basin and locks. By the Second Ordnance Survey Map of 1903, Jessop's Lock had been taken out of commission and its swing bridge replaced with a fixed bridge with sluices under, and a goods railway line passed over both junction locks until it was removed in the late C20. The basin, locks and associated machinery were maintained, repaired and updated at various stages from the early C20. A new swing bridge was constructed across Junction Lock in 1925 by Lysaght’s and Company, who had previously built Ashton Swing Bridge on the New Cut (1905, Grade II). By the early C20, a ‘gridiron’ structure was built alongside the former north entrance lock as a temporary dock.

In the 1960s, a new road and bridge complex with three two-level interchanges was built over Cumberland Basin. It included over three-quarters of a mile of viaducts, a pre-stressed concrete bridge over the River Avon, and one of the largest swing bridges in the country. The new bridge made the two Brunel swing bridges below it defunct, although the 1925 Junction Lock swing bridge continued in use for motor traffic as part of the new scheme. Other changes to the basin included the insertion of elevated ramps between the basin and the two Grade II listed bond warehouses, and the moving of some mooring posts and bollards. A concrete plaque with benches was erected to mark the completion of the project and is positioned to enjoy the view down the Avon Gorge, which has been celebrated since at least the early C19. A stabilisation project for the basin was completed in 1991 and the timber lock gates to Junction Lock were replaced in 2009. For most of the C20 a goods railway line ran across both junction locks. The rail bridges have since been removed and Jessop’s Lock is used for mooring in the C21. The ‘gridiron’ by the entrance locks had fallen into disuse and was covered in mud by the C21.

Fixtures to the basin and lock walls show the emergence and development of automated dock operation from the 1840s with examples of manual capstans, hydraulic mechanisms below surface level associated with the Underfall Yard hydraulic pumps, electrically driven capstans, and hydraulic equipment installed in 2010.

Reasons for Listing

Cumberland Basin walls and associated features including Junction Lock swing bridge, Bristol, is listed at Grade II for the following principal reasons:

Architectural interest:

* Cumberland Basin is a rare example of a tidal basin design and a critical part of Bristol’s Floating Harbour, which in the early C19 was a bold constructional achievement;
* from initial construction through successive improvement schemes, the principal structures were built using substantial and well-crafted materials in innovative forms to resolve the challenges presented at this location on the River Avon;
* as an original design by Thomas Jessop, a canal engineer of national significance, with improvements and innovations by engineer Thomas Howard;
* the requirement for improvement using advances in technology has resulted in an evolved dock and basin site that has clear historic phasing showing changing industrial activities and methods of power from the early C19.

Historic interest:

* the creation of Cumberland Basin helped the Port of Bristol to compete in international mercantile trade from the early C19;
* as part of a city-scale historic water management system it is testament to the ambition and ingenuity of the early Industrial Age and the engineers that this country produced.

Group value:

* this forms part of an important historic group with other attached listed assets including Brunel's South Entrance Lock and Swing Bridge, Brunel's Swing Bridge alongside North Entrance Lock (both Grade II*) and other associated listed structures in and around Cumberland Basin and Underfall Yard.

External Links

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