good practice guidelines for flood risk mapping

www.floodrisk.org.uk EPSRC Grant: EP/FP202511/1

Good Practice Guidelines for Flood Risk Mapping

Keith Beven, Lancaster UniversityWith Dave Leedal (Lancaster), Jeff Neal and Paul Bates (Bristol),

Caroline Keef, Neil Hunter and Rob Lamb (JBA Consulting), Simon McCarthy (Middlesex) and Jon Wicks (Halcrow)

www.floodrisk.org.uk EPSRC Grant: EP/FP202511/1

Flood Risk Mapping: framing the application• Planning decisions

• Emergency planning

• Flood damage assessments and defence design

• Insurance

• Generating householder resilience

• ……

www.floodrisk.org.uk EPSRC Grant: EP/FP202511/1

Sources of Uncertainty in Flood Risk Mapping

www.floodrisk.org.uk EPSRC Grant: EP/FP202511/1

Guidelines for Good Practice as Decision Trees• Assumptions to be agreed between analyst and

stakeholder(s)…..provides framework for discussing and handling knowledge uncertainties

• Explicit agreement and record means that later evaluation and review can be carried out

• Default options, or decision tree of potential options

www.floodrisk.org.uk EPSRC Grant: EP/FP202511/1

Guidelines for Good Practice as Decision Trees

Source Uncertainties

Pathway Uncertainties

Receptor Uncertainties

www.floodrisk.org.uk EPSRC Grant: EP/FP202511/1

Decision Tree for Design Flood Magnitude

www.floodrisk.org.uk EPSRC Grant: EP/FP202511/1

Case Study: Modelling inundation at Mexborough for the AEP 0.01 event given observations from 2007

www.floodrisk.org.uk EPSRC Grant: EP/FP202511/1

Mexborough Risk Mapping: Defining Input Uncertainties

WinFAP estimate of 0.01 AEP (T100) flood peak at Adwick

Mean: 86.6 (m3s-1)

Var: 6.25 (m3s-1)

www.floodrisk.org.uk EPSRC Grant: EP/FP202511/1

FRMRC Visualisation Tool

www.floodrisk.org.uk EPSRC Grant: EP/FP202511/1

www.floodrisk.org.uk EPSRC Grant: EP/FP202511/1

www.floodrisk.org.uk EPSRC Grant: EP/FP202511/1

Summary• Guidelines for good practice as decision trees

allows dialogue and audit of difficult decisions about uncertainty

• Good visualisation tools required to communicate meaning of results to users and stakeholders (see demonstration)

• Full FRMRC Guidelines Report will be available shortly