Immediate geomorphological impact and fluvial system response to the Cumbria floods November 2009

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Between November 18th - 20th 2009 Cumbria, NW England was hit by an exceptional precipitation event producing an unprecedented total of 372 mm of rainfall. Over the 24 h period between November 19th-20th alone, 313 mm of rain fell at Seathwaithe. This was equivalent to a month's precipitation and set a new UK record (Met. Office, 2009, previously 279 mm). The flood was the biggest event recorded in this region and had major consequences for population and infrastructure over a large area, as well as involving loss of human life. Due to its system-wide impact, the November 2009 flooding in Cumbria presents an unparalleled opportunity to gain insight into the controls on, and impact of, an extreme flood within upland, lowland parts of a large catchment. This project aims to examine the whole river corridor of the river Derwent from the headwaters, through Bassenthwaite Lake to the Lowland agricultural/urban catchment identifying key impacts and linkages. Quantifying erosion and sedimentation during extreme events is crucial so that effective hazard management can be undertaken in the short term and long-term spatially targeted management strategies devised. To achieve this, field-data must be collected in the immediate aftermath of the event to ensure essential features of the event are fully documented. Our main objectives are to produce a rapid, structured field inventory of the immediate geomorphic impact of rainfall and flooding on fluvial systems within the River Derwent river corridor along a headwater to coast transect; provide a rapid geomorphic assessment of the role of scour and sedimentation in the vicinity of bridges to discriminate factors influencing bridge collapse and so inform future design practice; identify areas of risk for remobilisation of flood-deposited sediments; delivery of hillslope sediments and hotspots of erosion in the River Derwent to identify zones at risk from future flood events and; work with project partners (EA and LDNPA) and local stakeholders in designating catchment zones that are 'at risk' from erosion and sedimentation.