Exploratory modeling: A tool for communicating the future: A case study of valuing flexibility in flood defense strategies

Exploratory modeling: A tool for communicating the future: A case study of valuing flexibility in flood defense strategies

Karkhaneh, A.

Thissen, W.A.H. (mentor)
Bots, P.W.G. (mentor)
Zevenbergen, C. (mentor)
Herder, P.M. (mentor)

Technology, Policy and Management

Multi Actor Systems Department

Engineering and Policy Analysis/Policy Analysis

2011-07-15

Decision-making for flood defense while facing a considerable change in driving forces demands other methods than the traditional approach of forecasting and optimal policy selection. Exploratory modeling can be a candidate for helping adaptive policymaking to deal with the uncertainties that confront decision-makers. In adaptive policymaking where changes , policies are considered that respond to changes over time. This thesis addresses the question whether exploratory modeling is appropriate to support the design of flood defense strategies and in particular to assess the value of flexibility in such designs. The literature review of this thesis explores the concept of flexibility and shows that exploratory modeling as a method for handling uncertainty can contribute to system control as well as system resilience, and to scientific analysis as well as process management. The case study of this thesis demonstrates the application of exploratory modeling to flood defense strategies. It shows (1) how alternative strategies can be compared and evaluated while considering seven uncertain system parameters, (2) how the relative performance of strategies can be expressed as a regret value, and (3) how these values can be visualized to let decision-makers see how changes in parameters impact on their regret of decision-maker. These 3 goals reached by an exercise of exploratory modeling. Interpretation of computer model of a pre-investment analysis leads to selection of most robust strategy. Beside the help of visualization technique to see and compare performance of different strategies, a tool developed that counts and compare performance of strategies based on their regret value. I call this tool “Regret Frequency Table”. After finding the robust strategy which in this case was “Dike relocation” there was a need to see is this strategy flexible in terms of design to let future developments or not. Therefore based on interviews and gathered information, a decision tree has been draw to see if selected strategy can let future developments. It emerged that it can support couple of available measures in project in future. This conclusion leads to an extension of practice of exploratory modeling to apply adaptive policymaking approach to see the performance of selected strategy after taking the next step. This extension of exploratory modeling included the selection of a signpost for taking the next step. Signpost selection depends on (1) risk tolerance of decision maker (2) and model structure. The main conclusion in this step is that the sign post should be a part model; either a component of model or a parameter of model. This outcome leads to selection of a component and a parameter in model with two different values corresponding to different risk attitudes of decision maker. The results again fitted into regret frequency table and the outcome has been compared based on regret value of strategy before taking the next step. This allows seeing the value of flexibility relatively in terms of how many percent it improves the no regret values of a flexible strategy after implementing future developments. This practice lets decision maker to make his final decision about next step based on his attitude toward risk. The final outcome of research is a new approach of practicing exploratory modeling tailored for adaptive approach of policy making. I call this method “Exploratory Modeling for Adaptive Policies”. It borrows seven steps from exploratory modeling analysis (EMA) and adds three more steps to adjust the practice for adaptive policy making.

Exploratory modeling
Adaptive policymaking
Uncertainty
Robust decision making
Regret frequency scoring
Flood defence strategy
Flood risk management
Pre-investment analysis
Flexibility

http://resolver.tudelft.nl/uuid:c2c954c6-82ed-4d6c-8b59-b5e5379f1d83

2011-07-14

Campus only

Student theses

master thesis

(c) 2011 Karkhaneh, A.