Title: Cost-effectiveness analysis of reinforcement strategies for (multifunctional) flood defences

Authors: Fatemeh Anvarifar; Matthijs Kok; Wil Thissen; Chris Zevenbergen; Defne Osmanoglou; Behrouz Raftari Tangabi

Addresses: Faculty of Civil Engineering and Geosciences, Department of Hydraulic Engineering, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands ' Faculty of Civil Engineering and Geosciences, Department of Hydraulic Engineering, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands ' Faculty of Technology, Policy and Management, Department of Multi Actor Systems, Delft University of Technology, Jaffalaan 5, 2628 BX Delft, The Netherlands ' Department of Water Science and Engineering, UNESCO-IHE, P.O. Box 3015, 2601 DA Delft, The Netherlands ' Faculty of Civil Engineering and Geosciences, Department of Hydraulic Engineering, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands ' Faculty of Electrical Engineering, Mathematics and Computer Science, Department of Applied Mathematics, Delft University of Technology, Mekelweg 4, 2628 CD Delft, The Netherlands

Abstract: Dike reinforcement decision making under uncertainty is a challenging task. This paper examines whether increasing the managerial flexibility of a reinforcement strategy can improve the lifecycle cost-effectiveness for the Dutch flood defences. Two flexible strategies are developed and compared to an inflexible baseline strategy. The strategies are examined in eight case studies, two sea level rise scenarios, and four discount rates. It is shown that increasing the flexibility of reinforcement can improve the cost-effectiveness for monofunctional dikes. The relative cost-effectiveness of flexible strategies decreases as the dike becomes multifunctional. The results prove to be sensitive to the choice of the scenario and discount rate. It is concluded that reinforcement decision making should address uncertainty explicitly and account for smaller scale developments around the dike. It is suggested that current engineering practice can be improved if the possibility of a variable design lifetime is also addressed in reinforcement decision making.

Keywords: climate change; cost-effectiveness; flexibility; flood defences; lifecycle costs; multifunctional dikes; reinforcement; scenario; sea level rise; strategy; uncertainty.

DOI: 10.1504/IJCIS.2017.089240

International Journal of Critical Infrastructures, 2017 Vol.13 No.4, pp.297 - 328

Received: 28 Sep 2016
Accepted: 13 Mar 2017

Published online: 10 Jan 2018 *

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