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Using a scenario-neutral framework to avoid potential maladaptation to future flood risk

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posted on 12.02.2019 by Ciaran Broderick, Conor Murphy, Robert Wilby, Tom Matthews, Christel Prudhomme, Mark Adamson
This study develops a coherent framework to detect those catchment types associated with ahigh risk of maladaptation to futureflood risk. Using the“scenario‐neutral”approach to impactassessment the sensitivity of Irish catchments tofluvialflooding is examined in the context of nationalclimate change allowances. A predefined sensitivity domain is used to quantifyflood responses to +2 °Cmean annual temperature with incremental changes in the seasonality and mean of the annual precipitationcycle. The magnitude of the 20‐yearflood is simulated at each increment using two rainfall‐runoff models(GR4J, NAM), then concatenated as response surfaces for 35 sample catchments. A typology of catchmentsensitivity is developed using clustering and discriminant analysis of physical attributes. The same attributesare used to classify 215 ungauged/data‐sparse catchments. To address possible redundancies, the exposure ofdifferent catchment types to projected climate is established using an objectively selected subset of theCoupled Model Intercomparison Project Phase 5 ensemble. Hydrological model uncertainty is shown tosignificantly influence sensitivity and have a greater effect than ensemble bias. A nationalflood riskallowance of 20%, considering all 215 catchments is shown to afford protection against ~48% to 98% of theuncertainty in the Coupled Model Intercomparison Project Phase 5 subset (Representative ConcentrationPathway 8.5; 2070–2099), irrespective of hydrological model and catchment type. However, results indicatethat assuming a standard national or regional allowance could lead to local over/under adaptation. Herein,catchments with relatively less storage are sensitive to seasonal amplification in the annual cycle ofprecipitation and warrant special attention.

Funding

The authors acknowledge theEnvironmental Protection Agency(EPA) of Ireland and the Office ofPublic Works (OPW), which fundedthis work under project 2014‐CCRP‐MS.16.

History

School

  • Social Sciences

Department

  • Geography and Environment

Published in

Water Resources Research

Citation

BRODERICK, C. ... et al., 2019. Using a scenario-neutral framework to avoid potential maladaptation to future flood risk. Water Resources Research, 55 (2), pp.1079-1104.

Publisher

© the Authors. Published by American Geophysical Union (AGU)

Version

VoR (Version of Record)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Publication date

2019

Notes

This is an Open Access Article. It is published by American Geophysical Union under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

ISSN

0043-1397

Language

en

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