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Cast Iron Aqueduct, Flash Lane
Whitewebbs Wood, Enfield, London, UK
associated engineer
Not known
date  1820 - 1821
era  Georgian  |  category  Aqueduct  |  reference  TQ321994
ICE reference number  HEW 277
Flash Lane Aqueduct was built to carry the New River over Cuffley Brook, when the course of the river was diverted. Further straightening of the New River in the 19th century rendered the aqueduct obsolete, and it fell into disrepair but has been restored recently. It is clearly visible and accessible from Flash Lane.
New River (1608-13) was built to bring drinking water from Hertfordshire to London. Before this aqueduct was built, the New River flowed under Cuffley Brook in a 400m long lead-lined timber trough or ‘flash’. The flash was part of the original watercourse and was rebuilt by Robert Mylne in 1775.
The present structure is located on the Claysmore estate, then owned by Edward Harman and bought by James Whatman Bosanquet in 1847 (the original house has been demolished, though the estate is still owned by the Bosanquet family). Harman bought the loop of the New River that crossed his land west of Flash Lane and dammed Cuffley Brook to create an artificial lake within the loop. The New River was diverted, and the embankment and cast iron aqueduct were constructed to carry New River over the brook.
The aqueduct has a two span cast iron trough, carried on brick piers and segmental arches. It has a base plate with seven integral fish-bellied cast iron upstand stiffeners about 25mm thick. The ironwork cost £252.
During the latter half of the 19th century many of the New River’s loops were straightened and its total length decreased by 30%. The river conduit was diverted in this area in 1859 and also circa 1890, when it was re-routed south to Bush Hill Park. The new course meant that the aqueduct was not required and its condition deteriorated.
Enfield Archaeological Society excavated the site in 1968 and produced drawings of the aqueduct in 1970. The structure is now a Scheduled Ancient Monument.
The aqueduct was restored in 1998 but was later placed on English Heritage’s ‘at risk’ register after being damaged by the surrounding trees.
A seven-week £30,000 programme of repairs was carried out in October and November 2010, funded by English Heritage and managed by Enfield Council. The whole structure was cleaned, and the cast iron trough, brickwork and railings repaired. It is no longer at risk.
Ironwork (1821): Hunter & English, Bow
Ironwork repairs and maintenance (2010): Fergal Contracting Company Ltd
Research: ECPK
reference sources   CEH Lond

Cast Iron Aqueduct, Flash Lane