Department of Infrastructure Castletown Tidal Flooding & Sea Defence August 2014.
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Transcript of Department of Infrastructure Castletown Tidal Flooding & Sea Defence August 2014.
Department of Infrastructure
CastletownTidal Flooding & Sea Defence
August 2014
2002 • Tide model created• Storm Surge Model • Flood Maps• 2002 prediction
accuracy +- 500 mm Meters
• 2014 prediction accuracy +- 50 mm
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January 2014
• Flooding areas– Hope Street– Back Hope Street– Springfield Terrace– Victoria Road– Milner Terrace– Athol street – Brewery Walf
• Tidal Overtopping– Douglas Street– The Promenade
J Robinson 3
January 2014 Structural Damage
• Damage to sea wall at St Mary’s Car Park
• Damage to breakwater
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Lessons Learnt/Improvements
• Shortage of sandbags
• Poor communication– Government – Businesses,
Residents and LA’s
• Understanding of the flooding routes
• Drains, Lanes, Roads
• Area Protection works
5J Robinson
February 2014
• Improved flood protection at end of Hope Street.
• Gullies and manholes covered to prevent backing up.
• Early deployment of sandbags and increased availability
• Improved communication with businesses, residents and local authorities
• Pre-planned road closures, advertised in advance
J Robinson 6
St Mary’s Car Park
• Castletown Commissioners reconstructed the sea wall and car park
– 250T of temporary rock armour to protect the area
– Construction of new retaining wall– Improved land drainage– Increased car parking– Viewing area being created
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Tactical Improvements Since January• 20,000 filled
sandbags• Flood barriers• Portable flood
barriers• Maintenance of
non-return valves to harbour
• Pre-planned road closures
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Portable Flood Barriers• Demountable flood
defence barrier• Rapidly deployed• Flexible, easy
connection to walls• Pods fill with rising
flood waters• 900 mm high units• No bolting or
construction work needed
J Robinson 9
Fixed Flood Barriers• Permanently fixed
wall channels• Lightweight
aluminium panels• Durable rubber
seals• Units locked in
place with compression screws
J Robinson 10
Policy and Strategy Development• A high level cost
benefit analysis complete
• Investigation of defence options and budget costs commissioned
J Robinson 11
Up Coming Tides• Tide height
– 10-15 August 14– 13th- Chart 4.15 m– 8-12 September 14– 11th Chart 4.21 m
• Castletown Harbour typically 0.40-0.50 lower than above
• This only starts to be predictable 36 hours out
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