Robustness Analysis for Flood Risk Management Planning: on Risk-Based Decision Making Beyond Simple Economic Reasoning, Exemplified for the Meuse River (Netherlands) (PAP014737)

Código

PAP014737

Autores

Frans Klijn, Marjolein J. P. Mens, Nathalie E. M. Asselman

Tema

Impact of climate change on flood risk

Resumo

Flood risk management planning involves making decisions on which measures toimplement, and when to do so. Rational decision making on which comprehensive strategy to implement,or on which measures to take first, requires ex-ante assessments that question whether flood risk iseffectively reduced, and against which societal costs. Such decision making is usually supported by costbenefit analysis (CBA) or cost effectiveness analysis (CEA). The key economic assessment criterionapplied may be the ratio between the benefits and costs of a measure or strategy (B/C), or, alternatively,the minimum of the sum of costs and (residual) flood risk. However, these metrics treat lowprobability/large consequence risk and high-probability/small consequence risk as equal, which is oftenconsidered unsatisfactory in a decision making context. Robustness analysis can be used to account forthis ?flaw?, as it gives insight into the relationship between flood magnitude and flood consequences at thescale of an entire flood risk system, thus revealing how sensitive such a system is and whether it can stillrecover. A more robust system is able to deal with a variety of extreme floods, including those thatexceed the ?design flood?. This paper examines how a variety of strategic alternatives for flood riskmanagement along the Meuse River in the Netherlands score on various economic criteria and how theywould be assessed from a robustness perspective. The strategies include making room for the river,strengthening embankments, and various combinations of these. The results show that the three criteriaindeed lead to a different ranking of which strategy to prefer. This supports our claim that a robustnessperspective may help to select a strategy that is not only economically efficient, but may also be moresustainable in view of uncertainties into the future.