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Replica of the Mohne Dam, in the grounds of the Building Research Establishment, Garston

List Entry Summary

This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Culture, Media and Sport.

Name: Replica of the Mohne Dam, in the grounds of the Building Research Establishment, Garston

List entry Number: 1020749

Location

The monument may lie within the boundary of more than one authority.

County: Hertfordshire

District: St. Albans

District Type: District Authority

Parish: St. Stephen

National Park: Not applicable to this List entry.

Grade: Not applicable to this List entry.

Date first scheduled: 16-Oct-2002

Date of most recent amendment: Not applicable to this List entry.

Legacy System Information

The contents of this record have been generated from a legacy data system.

Legacy System: RSM

UID: 32454

Asset Groupings

This list entry does not comprise part of an Asset Grouping. Asset Groupings are not part of the official record but are added later for information.

List entry Description

Summary of Monument

Legacy Record - This information may be included in the List Entry Details.

Reasons for Designation

The replica of the Mohne Dam in the grounds of the Building Research Establishment at Garston is a unique survival; it is the only test dam to survive from a small number built for the dam destruction experiments at Garston and as such is not only of national but also international importance. It gives testimony to the exhaustive nature of the top secret experimental bombing trials prior to the Dambuster Raid on the Ruhr river dams in Germany. It also illustrates the multiplicity of tasks for which local construction companies as well as national scientific staff could be conscripted into during the course of World War II. The Dambuster Raid is a world famous event. The secret trials prior to the event are, however, not so well known and the Garston replica gives graphic testimony to this lesser known side of the story.

History

Legacy Record - This information may be included in the List Entry Details.

Details

The monument includes a replica of the Mohne Dam, built to a scale of 1:50, located within woodland in the centre of the grounds of the Building Research Establishment at Garston.

The replica is some 14m long and 1m high with a maximum thickness of 0.6m at its base. The dam wall holds back a body of water forming a D-shaped pond with a maximum width of 15m; the stream feeding the dam overflows through the centre of the dam wall into a small drainage channel. The dam wall itself is constructed of over 600,000 miniature mortar cubes with a concrete core; this copies the construction technique used in the real Mohne dam which is made of massive granite blocks with puddled clay to seal the join at its foundations.

The replica dam was constructed in December 1940 following discussions on proposals to strike a number of dams along the River Ruhr in Germany. Dr William Glanville the Director of the Road Research Laboratory at Harmondsworth invited the eminent engineer Barnes Wallis to the Building Research Station to discuss the alternatives with the then Head of Engineering Dr Norman Davey. It was agreed that scale models would be built to determine the best method of attack. Constructed in strict secrecy, the Garston replica took a local workforce just seven weeks to build. Tests on the most effective means of destruction included the detonation of ten charges on the `wet' side of the dam at distances of between 1 and 3 feet. Other ideas included the dropping of charges with pressure fuses at the base of the dam and then initiating simultaneous detonation with a single large bomb.

The Garston replica was the first step in a series of extensive tests on the best means of destroying the Ruhr dams; other model dams (none of which survive) were built and tested by Dr Glanville's staff before final experiments on a real dam near Rhayader in the Welsh mountains. In the event Barnes Wallis devised his unique bouncing bomb as a means to breach the walls of the Ruhr dams. On the 16th May 1943 19 Avro Lancasters of 617 Squadron left RAF Scampton led by Wing Commander G P Gibson loaded with the bouncing bombs designed by Barnes Wallis. The raid was deemed a success as one bomb inflicted a gap some 20m high and 77m long on the Mohne dam; the Eder dam was also breached. Although the dams were repaired fairly quickly (the Mohne Dam took just four months), the action provided a huge boost to the morale of the Allied war effort and is consequently world famous as the `Dambuster Raid'.



MAP EXTRACT The site of the monument is shown on the attached map extract. It includes a 1 metre boundary around the archaeological features, considered to be essential for the monument's support and preservation.

Selected Sources

Books and journals
Ottaway, S, Dambuster A Life of Guy Gibson VC, (1994)
'Defence Lines Newsletter of the Defence of Britain Project' in Lilliput's Dambusters, , Vol. 7, (1997), 3
Websites
, accessed from
, accessed from
www.ruhrverband.de/MOHNE.HTM, accessed from
Other
Tyler, S, MPP Film, (1998)

National Grid Reference: TL 12429 01586

Map

Map
© Crown Copyright and database right 2017. All rights reserved. Ordnance Survey Licence number 100024900.
© British Crown and SeaZone Solutions Limited 2017. All rights reserved. Licence number 102006.006.
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The above map is for quick reference purposes only and may not be to scale. For a copy of the full scale map, please see the attached PDF - 1020749 .pdf

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This copy shows the entry on 22-Nov-2017 at 04:10:21.

End of official listing