Broderick, Ciaran and Murphy, Conor and Wilby, Robert L. and Matthews, Tom K.R. and Prudhomme, Christel and Adamson, Mark (2019) Using a Scenario‐Neutral Framework to Avoid Potential Maladaptation to Future Flood Risk. AGU Journal, 55 (2). pp. 1079-1104.

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Abstract

This study develops a coherent framework to detect those catchment types associated with a high risk of maladaptation to future flood risk. Using the “scenario‐neutral” approach to impact assessment the sensitivity of Irish catchments to fluvial flooding is examined in the context of national climate change allowances. A predefined sensitivity domain is used to quantify flood responses to +2 °C meanannualtemperaturewithincrementalchangesintheseasonalityandmeanoftheannualprecipitation cycle. The magnitude of the 20‐year flood is simulated at each increment using two rainfall‐runoff models (GR4J, NAM), then concatenated as response surfaces for 35 sample catchments. A typology of catchment sensitivityisdevelopedusingclusteringanddiscriminantanalysisofphysicalattributes.Thesameattributes areusedtoclassify215ungauged/data‐sparsecatchments.Toaddresspossibleredundancies,theexposureof different catchment types to projected climate is established using an objectively selected subset of the Coupled Model Intercomparison Project Phase 5 ensemble. Hydrological model uncertainty is shown to significantly influence sensitivity and have a greater effect than ensemble bias. A national flood risk allowance of 20%, considering all 215 catchments is shown to afford protection against ~48% to 98% of the uncertainty in the Coupled Model Intercomparison Project Phase 5 subset (Representative Concentration Pathway 8.5; 2070–2099), irrespective of hydrological model and catchment type. However, results indicate that 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 of precipitation and warrant special attention.

Item Type:	Article
Keywords:	Climate change; flooding hydrological model uncertainty; scenario neutral; Ireland catchment regionalization;
Academic Unit:	Faculty of Social Sciences > Research Institutes > Irish Climate Analysis and Research Units, ICARUS
Item ID:	10878
Identification Number:	https://doi.org/10.1029/2018WR023623
Depositing User:	Conor Murphy
Date Deposited:	01 Jul 2019 13:44
Journal or Publication Title:	AGU Journal
Publisher:	Wiley
Refereed:	Yes
URI:
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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