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Briefing Note: Removal of Pinch Points

This briefing note sets out IWA’s aspirations for the long-term removal of pinch points around the waterways system.  For the purposes of this briefing note, a ‘pinch point’ is defined as a place where the minimum gauge for a waterway has been reduced to an extent that it prevents the passage by boats of the original gauge intended for that waterway.  Pinch points have been created over the years and may affect the available height, depth and width of navigation as it passes through specific structures and locations.

IWA monitors any proposed new developments on waterways and will campaign for new structures to consider the original gauge of that waterway in order to avoid new pinch points being created.

A recent example of potential future pinch points is the proposed HS2 High Speed Railway about which IWA is lobbying to ensure that headroom at all the proposed crossings of waterways both navigable and under restoration will not create any new pinch points.

[The photo shows Hurleston Bottom Lock at the entrance to the Llangollen Canal  –  by Roy Heatley]

IWA encourages the increased use of the waterways by all types and sizes of craft within the relevant craft gauge (i.e., the maximum size of vessels able to use a waterway) and will press navigation authorities to maintain each waterway in a satisfactory condition to safely accommodate vessels of its craft gauge and to permit access by such vessels.  IWA will oppose all attempts to reduce the craft gauge of a waterway and will press for the restoration of dimensions suitable for the passage of vessels of the constructed gauge where subsequent works or deterioration (such as subsidence) have created pinch points.  IWA considers that the opportunity should be taken to make minor improvements to achieve the appropriate constructed gauge where structures of heritage value are repaired or restored.

Where works are planned that will affect a waterway (e.g., road, rail, or utilities crossings; bridge reconstruction; riparian development) IWA will press for retention of dimensions suitable for the passage of vessels of craft gauge.  Where such works are planned to cross the route of a proposed new waterway, or of an existing waterway proposed for restoration or enlargement, the Association will press for the provision of adequate clearance for vessels of the intended craft gauge so that no new pinch points are created.

The constructed gauge varies across different waterways, and IWA seeks to ensure the protection of this gauge as a minimum in each case.  The standard craft gauges for narrow and broad waterways are:

  • Length: 22 m (72’2”)
  • Beam: 2.15 m (7’1”) for narrow waterways , 4.35 m (14’3”) for broad waterways
  • Draught: 1.3 m (4’3”) for narrow waterways, 1.5 m (5.0”) for broad waterways
  • Air Draught: 2.2 m (7’3”) for narrow waterways, 2.7 m (8’10”) for broad waterways

[The photo shows the stop lock at Marston Junction, a pinch point on the Ashby Canal  –  by John Gagg, taken in 1973]

On narrow waterways 2.8 m (9’2”) headroom is preferred although 2.5 m (8’2”) would comply with this policy.  On broad waterways 3.0 m (9’10”) headroom is desirable.  The required headroom should be provided over a width of at least craft gauge beam.  For safety reasons, the Association considers that there should be at least 0.3 m clearance above the craft air draught.

IWA was pleased to note the work by Canal & River Trust a few years ago at Hurleston Bottom Lock, where boats wider than 6’10” used to get stuck and could not then access the Llangollen Canal, and in rebuilding of one of the lock walls at Stret Lock on the Chesterfield Canal in order to allow passage by boats wider than 6’10”.  Further works will, however, be required on other locks on this same canal to allow passage by all boats of narrow beam.

Two of the pinch points that IWA would particularly wish to see addressed in the long term are:

  • Ellesmere Port (where the M53 bridge restricts waterway that historically took 14ft wide boats to 11ft)
  • Froghall Tunnel, where the headroom is reduced and the local IWA branch is campaigning and investigating ways of increasing the headroom through the tunnel

More detailed guidance can be found in IWA’s Policy Document on Standards for Construction, Restoration and Maintenance of Inland Waterways.

[The photo shows Froghall Tunnel, a pinch point on the Caldon Canal  –  by Mark Hewson]

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