Flood Investigation Report 2012
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Information Classification: CONTROLLED Flood Investigation Reports 2012 Last updated: 23/04/2018 Overview 2012 2012 was the wettest year on record in England, despite the first three months of the year being declared a drought. Flash flooding mainly resulting in surface water occurred on short occasions in July and August. Coastal flooding occurred in both October and December. Prolonged rainfall led to surface water and fluvial flooding in November and was then repeated in December, affecting many of the same communities and properties. 6 July 2012 Heavy rain across the county led to mainly surface water flooding of some properties and roads. Flooding occurred at properties in Bugle, St Austell, Penzance and in the Camborne and Redruth areas. 17 August 2012 In the morning, two bands of rain swept across Cornwall causing surface water flooding problems mainly affecting roads. A section of the A38 in the Glynn Valley between Bodmin and Liskeard was closed for around 2 hours due to flooding. In Truro, businesses in Bridge Street were inundated by surface water coming off the highway. 17 and 18 October 2012 There was coastal flooding when a low pressure weather system brought a storm surge and gale force winds that coincided with the spring tides. Flooding particularly affected Looe, Mevagissey and Fowey but was also reported at Bude, Port Isaac, Polzeath, Perranporth, Hayle, Newlyn, Penzance, Falmouth and Tresillian. Sea defences were badly damaged at Long Rock. • Flood Investigation Report for Fowey (Oct) • Flood Investigation Report for Looe (Oct) • Flood Investigation Report for Mevagissey (Oct) 22 to 27 November 2012 This event occurred at the end of a particularly wet summer and antecedent conditions meant that groundwater levels were already high, soils saturated and river levels elevated. The overall event was made up of a number of contiguous events starting with a rainstorm on Thursday 22 November 2012. Friday was fairly dry. The bulk of the rainfall fell during Saturday 24 November. However, rainstorm conditions endured throughout Sunday, Monday and into Tuesday 27 November 2012. Flooding occurred across Cornwall during this event. Notably river levels on the Hayle, Gannel and SeatonRivers were the highest in over 40 years of recording. Across Cornwall an estimated 260 properties flooded. Many of these were isolated incidents that do not trigger a Flood Incident Report. • Rainfall analysis for 22-27 November 2012 • Flood Investigation Report for Cawsand • Flood Investigation Report for Hessenford • Flood Investigation Report for Kingsand • Flood Investigation Report for Ladock • Flood Investigation Report for Millbrook • Flood Investigation Report for Newlyn Information Classification: CONTROLLED • Flood Investigation Report for Perranporth • Flood Investigation Report for Polperro • Flood Investigation Report for Portmellon (further detail required) • Flood Investigation Report for St Just in Roseland (further detail required) • Flood Investigation Report for Trenear 14, 15 and 16 December 2012 Further coastal flooding occurred when a series of spring tides coincided with a low pressure system and strong south easterly winds. The tide level was not exceptional but the combination of a large swell with high winds led to overtopping of sea defences and flooding of many properties, especially along the south coast. Tidal flood gates were shut at Truro and Polperro. Large waves resulted in the closing of the promenade at Penzance. • Flood Investigation Report for Fowey (Dec) • Flood Investigation Report for Looe (Dec) • Flood Investigation Report for Mevagissey (Dec) 18 to 31 December 2012 This event occurred at the end of a particularly wet summer and autumn and antecedent conditions meant that groundwater levels were already high, soils saturated and river levels elevated. In addition, it came just one month after another major event in November that led to widespread flooding across Cornwall. The overall event is considered to have started late on Tuesday 18 December and lasted for 2 weeks. Within this there were periods of more intense rainfalls. Flooding occurred across Cornwall during this event affecting many of the same properties that were flooded in November. • Rainfall analysis for 18-31 December 2012 • Flood Investigation Report for Helston • Flood Investigation Report for Ladock • Flood Investigation Report for Lostwithiel • Flood Investigation Report for Mevagissey • Flood Investigation Report for Mousehole • Flood Investigation Report for Porthallow • Flood Investigation Report for Porthleven Cornwall Council Flood Investigation Report Date: 17&18 October 2012 Location: Mevagissey Details of the flood event Did five or more properties flood internally? Yes Did at least one property flood internally that has also Yes flooded internally within the last five years? If the answer to either question above is Yes then this Incident Report will form part of a Section 19 Flood Investigation Report and will need to be published. Description of weather conditions: A low pressure weather system brought a storm surge and gale force winds that coincided with the spring tides. Description of flood event: Fire fighters from Mevagissey attended the main square on the evening of Wednesday 17 October and helped with the clean-up after some businesses flooded. They also helped prevent floodwater from sweeping through properties and directed traffic through the town until police arrived at the scene. A number of businesses including the Ship Inn and the Mevagissey News were flooded internally as were some residential properties. No of properties flooded: 5? Source of flooding: Fluvial Surface water Coastal Other Main River Highways Tides Groundwater Ordinary Sewers Waves Other watercourse Agricultural Erosion Other Relevant authority Interest / notes Cornwall Council Coastal Authority Environment Agency Responsibilities for flooding from the sea South West Water Private/community Other Further actions: Are any further actions required? Yes / No Who? What? A strategic approach is required for defending Mevagissey against coastal flooding. Is there further information available on No record? Cornwall Council Flood Investigation Report Date: 24 November 2012 Location: Cawsand Details of the flood event Did five or more properties flood internally? Yes Did at least one property flood internally that has also Unknown flooded internally within the last five years? If the answer to either question above is Yes then this Incident Report will form part of a Section 19 Flood Investigation Report and will need to be published. Description of weather conditions: This event occurred at the end of a particularly wet summer and antecedent conditions meant that groundwater levels were already high, soils saturated and river levels elevated. The overall event was made up of a number of contiguous events starting with a rainstorm on Thursday 22 November 2012. Friday was fairly dry. The bulk of the rainfall fell during Saturday 24 November. However, rainstorm conditions endured throughout Sunday, Monday and into Tuesday 27 November 2012. Flooding occurred across Cornwall during this event. Description of flood event: During the evening of 24 November the Cawsand Stream rose in response to heavy rainfall. Sandbags were used to raise the banks but these were overtopped and water spilled onto St Andrews car park. The water backed up against the car park wall and then flowed down Armada Road, into The Square and across The Bound to the sea. No of properties flooded: 5 (1 shop, 1 pub, 2 residential & 1 gig clubhouse) Source of flooding: Fluvial Surface water Coastal Other Main River Highways Tides Groundwater Ordinary Sewers Waves Other watercourse Agricultural Erosion Other Relevant authority Interest / notes May consider proposing Property Level Cornwall Council Protection if residential properties are susceptible to repeated flooding. Responsibilities for managing flood risk Environment Agency from the Cawsand Stream, which is Main River. South West Water Private/community Other Further actions: Are any further actions required? Yes Who? Cornwall Council What? Consider candidate for PLP. Is there further information available on Yes – EA Reconnaissance map record? Cornwall Council Flood Investigation Report Date: 24 November 2012 Location: Hessenford Details of the flood event Did five or more properties flood internally? Yes Did at least one property flood internally that has also Unknown flooded internally within the last five years? If the answer to either question above is Yes then this Incident Report will form part of a Section 19 Flood Investigation Report and will need to be published. Description of weather conditions: This event occurred at the end of a particularly wet summer and antecedent conditions meant that groundwater levels were already high, soils saturated and river levels elevated. The overall event was made up of a number of contiguous events starting with a rainstorm on Thursday 22 November 2012. Friday was fairly dry. The bulk of the rainfall fell during Saturday 24 November. However, rainstorm conditions endured throughout Sunday, Monday and into Tuesday 27 November 2012. Flooding occurred across Cornwall during this event. Description of flood event: Water broke out of the left bank of the River Seaton upstream of the A378 road bridge, flooding the public house. At the same time surface water runoff flowed westwards down Fore Street until it met with the fluvial water, flooding properties and then returned