Department of Infrastructure Castletown Tidal Flooding & Sea - PowerPoint PPT Presentation

Department of Infrastructure Castletown Tidal 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 2

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 4

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 J Robinson 5

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 7

Tactical Improvements Since January • 20,000 filled sandbags • Flood barriers • Portable flood barriers • Maintenance of non-return valves to harbour • Pre-planned road closures 8

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 – 13 th - Chart 4.15 m – 8-12 September 14 – 11 th Chart 4.21 m • Castletown Harbour typically 0.40-0.50 lower than above • This only starts to be predictable 36 hours out 12

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