Flood risk from groundwater: examples from a Chalk catchment in southern England

Groundwater flooding has moved up the policy‐makers' agenda as a result of the United Kingdom experiencing extensive groundwater flooding in winter 2000/2001. However, there is a lack of appropriate methods and data to support groundwater flood risk assessment. The implications for flood risk assessment of groundwater flooding are outlined using a study of the Chalk aquifer underlying the Pang and Lambourn catchments in Berkshire, UK. Groundwater flooding in the Chalk results from the water table reaching the land surface and producing long‐duration surface flows (weeks to months), causing significant disruption to transport infrastructure and households. By analyzing existing data with a farmers' survey, it was found that groundwater flooding consists of a combination of intermittent stream discharge and anomalous springflow. This work shows that there is a significant challenge involved in drawing together data and understanding of groundwater flooding, which includes vital local knowledge, reasonable risk assessment procedures and deterministic modelling.

[1]  Chris Kilsby,et al.  Role of hydrology in managing consequences of a changing global environment , 2012 .

[2]  Christopher R. Jackson,et al.  Simulation of the spatio‐temporal extent of groundwater flooding using statistical methods of hydrograph classification and lumped parameter models , 2011 .

[3]  H. Wheater,et al.  Managing extremes in groundwater-dominated catchments: the Chalk of SE England , 2010 .

[4]  A. Gallagher,et al.  An early warning system for groundwater flooding in the Chalk , 2010 .

[5]  D. Cobby,et al.  Groundwater flood risk management: advances towards meeting the requirements of the EU floods directive , 2009 .

[6]  Serdar Korkmaz,et al.  Application of the coupled model to the Somme river basin , 2009 .

[7]  A. Ireson,et al.  A model for flow in the chalk unsaturated zone incorporating progressive weathering , 2009 .

[8]  A. Gallagher,et al.  Groundwater flooding in fractured permeable aquifers. , 2009 .

[9]  John Rees,et al.  Regional modelling of geohazard change , 2009 .

[10]  A. Ducharne,et al.  Multi-model comparison of a major flood in the groundwater-fed basin of the Somme River (France) , 2009 .

[11]  J. Maréchal,et al.  Karst flash flooding in a Mediterranean karst, the example of Fontaine de Nîmes , 2008 .

[12]  H. Jourde,et al.  A methodology for extreme groundwater surge predetermination in carbonate aquifers : Groundwater flood frequency analysis , 2008 .

[13]  M. Pitt.  Learning lessons from the 2007 floods , 2008 .

[14]  FLOOD 1. Final Report , 2008 .

[15]  John P. Bloomfield,et al.  Improving the understanding of the risk from groundwater flooding in the UK , 2008 .

[16]  A. Parkes,et al.  Towards groundwater flood risk mapping , 2007, Quarterly Journal of Engineering Geology and Hydrogeology.

[17]  R. Hall,et al.  Investigating the interdependencies between surface and groundwater in the Oxford area to help predict the timing and location of groundwater flooding and to optimise flood mitigation measures , 2007 .

[18]  A. Binley,et al.  Characterising groundwater-dominated lowland catchments: the UK Lowland Catchment Research Programme (LOCAR) , 2007 .

[19]  H. Rutter,et al.  Confidence and Groundwater Flood Susceptibility Mapping , 2007 .

[20]  T. Marsh,et al.  The summer 2007 floods in England and Wales – a hydrological appraisal , 2007 .

[21]  C. Neal,et al.  Hydro-ecological functioning of the Pang and Lambourn catchments, UK: An introduction to the special issue , 2006 .

[22]  J. Barker,et al.  Karstic behaviour of groundwater in the English Chalk , 2006 .

[23]  S. Fletcher,et al.  Streamflow generation in the Pang and Lambourn catchments, Berkshire, UK , 2006 .

[24]  G. Petts,et al.  Dynamics of river–aquifer interactions along a chalk stream: the River Lambourn, UK , 2005 .

[25]  Nadia Amraoui,et al.  Groundwater‐induced flooding in macropore‐dominated hydrological system in the context of climate changes , 2005 .

[26]  J. A. Hudson,et al.  The spatial distribution of groundwater flooding in a chalk catchment in southern England , 2004 .

[27]  Terry Marsh,et al.  The UK Floods of 2000–2001: A Hydrometeorological Appraisal , 2002 .

[28]  R. B. Bradford.  Controls on the discharge of Chalk streams of the Berkshire Downs, UK. , 2002, The Science of the total environment.

[29]  Joseph L. Jones,et al.  Ground-water flooding in glacial terrain , 2000 .

[30]  A. Meijerink,et al.  Statistical and analytical study of the propagation of flood-induced groundwater rise in an alluvial aquifer , 1998 .

[31]  A. MacDonald,et al.  Evidence for rapid groundwater flow and karst-type behaviour in the Chalk of southern England , 1998, Geological Society, London, Special Publications.

[32]  M. Hough,et al.  The United Kingdom Meteorological Office rainfall and evaporation calculation system; MORECS version 2.0; an overview , 1997 .

[33]  Andrew McKenzie,et al.  The physical properties of major aquifers in England and Wales , 1997 .

[34]  D. Banks,et al.  The Chalk as a karstic aquifer: evidence from a tracer test at Stanford Dingley, Berkshire, UK , 1995, Quarterly Journal of Engineering Geology.

[35]  M. Owen,et al.  2. Characteristics and yield in fissured chalk , 1978 .