Surface water flood warnings requirements and potential in England and Wales D.J. Parker * , S.J. Priest, S.S. McCarthy Flood Hazard Research Centre, Middlesex University, Trent Park, Bramley Road, London N14 4YZ, United Kingdom Keywords: Surface water flooding Pluvial flooding Rainfall alerts Flood warnings Professional emergency responders Public warning response abstract This paper examines the potential for developing surface water flood warnings in England and Wales by focusing upon the requirements of professional and public flood warning responders. The recent develop- ment of Extreme Rainfall Alerts (ERAs) presents an opportunity to develop such warnings. However, uncertainties concerning event probability, the location and likely impact of floods would significantly complicate the risk communication and warning response process limiting warning effectiveness. Feedback, interviews and workshops involving professional emergency responders and public focus groups allow the reception to existing ERAs and to proposed linked flood warnings to be gauged. For professional responders ERAs are useful and the majority take preparatory actions on receipt of them. There is support for surface water flood warnings among professional responders, particularly if uncertainties can be reduced and warnings tailored to their requirements. Higher quality linkages are required between rainfall intensity and duration and flooding and between forecasters, warners and the warned. Most flood experienced members of the public want surface water flood warnings but scepticism exists about ability to effectively provide them. Reasons include inherent forecasting uncertainties and lack of confidence in the responsible author- ities. Existing constraints on developing warnings include reliability issues surrounding flood warnings, the current level of understanding of probabilities and low levels of public flood risk awareness. Ó 2011 Elsevier Ltd. All rights reserved. Introduction The floods that struck England and Wales in the summer of 2007 were the most serious since 1947. Post-flood assessments revealed that two-thirds of properties flooded were affected by surface water floods (SWFs 1 ), largely produced by intense rainfall (Environment Agency 2007). Over 4 million properties are poten- tially at risk from this flooding type (Environment Agency, 2009; Environment Agency Wales, 2009). The Pitt Review into the 2007 floods called for SWF warnings (Pitt, 2008). Since the disastrous performance of fluvial flood forecasting and warning in 1998 (Bye & Horner, 1998), the Environment Agency has sought to improve flood forecasting, warning dissemination and public flood risk awareness but these improvements were of limited help in 2007 because there was no warning for SWFs. Following the Pitt Review the Met Office and the Environment Agency combined to further enhance flood forecasting capability. A pilot scheme was developed to issue ‘Extreme Rainfall Alerts’ (ERAs) to professional emergency responders (PERs) such as local authority highways departments and utility companies. This pilot occurred between July 2008 and April 2009 following which an ERA service was provided by a new joint Flood Forecasting Centre (FFC). The alerts are a first step towards potential SWF forecasting and warning. Research into flood warnings demonstrates the importance of discovering user requirements before designing and launching flood warnings (Emergency Management Australia, 1999; Parker, 2004). Not to proceed in this manner runs a high risk of warnings being of limited use, largely ignored or substituted by local informal warning systems (Parker & Handmer, 1998). The purpose of this paper is, therefore, to examine the potential for launching SWF warnings based on ERAs by exploring requirements and prefer- ences of PERs and the public. The characteristics of ERAs, feedback from PERS on existing ERAs and outcomes from PERs workshops and public focus groups are discussed. The paper is based on research sponsored by the Environment Agency which also included a technical assessment of ERAs (Priest, Parker, Hurford, & Lumbroso, 2010a) and a user assessment of potential SWF warning technical options (Priest et al., 2010b). Although there are data quality inadequacies, the technical assessment suggests that currently ERAs do not relate particularly well to SWFs in all areas. Existing experience of rainfall alerts and SWF warnings SWF warnings are currently rare (Priest et al., 2010b). In theory, they range from simply issuing a heavy rainfall alert implying * Corresponding author. Tel.: þ44 (0)20 8411 6101; fax: þ44 (0)20 8411 5403. E-mail address: denjpark@btinternet.com (D.J. Parker). 1 SWF(s) surface water flood(s); ERA(s) Extreme Rainfall Alert(s); PER(s) Profes- sional Emergency Responder(s). Contents lists available at ScienceDirect Applied Geography journal homepage: www.elsevier.com/locate/apgeog 0143-6228/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.apgeog.2011.01.002 Applied Geography 31 (2011) 891e900