1 UNCERTAINTY PROPAGATION AND RISK ANALYSIS IN WATER RESOURCE SYSTEM USING PROBABILISTIC OPERATION AND MODELLING APPROACH Research Fellow: Mulugeta Bereded Zelelew Supervisor: Associate Prof Knut Alfredsen Department of Hydraulic and Environmental Engineering October 28, 2008
2 CONTENTS 1. STATUS 2. BRIEF BACKGROUND AND RESEARCH OBJECTIVES 3. SHUFFLED COMPLEX EVOLUTION (SCE-UA), GENERAL PURPOSE GLOBAL OPTIMIZATION ALOGORITHM 4. IMPLEMENTATION OF THE SCE-UA FOR HBVPINE HYDROLOGICAL MODEL 5. WHAT IS NEXT? 6. COMMENT Mulugeta, UNCERTAINTY PROPAGATION AND RISK ANALYSIS IN WATER RESOURCE SYSTEM…
3 1. STATUS: � The final plan of the research was approved in June 2008 by the Doctoral committee “UNCERTAINTY PROPAGATION AND RISK ANALYSIS IN WATER RESOURCE SYSTEM USING PROBABILISTIC OPERATION AND MODELLING APPROACH” Mulugeta, UNCERTAINTY PROPAGATION AND RISK ANALYSIS IN WATER RESOURCE SYSTEM…
4 2. OBJECTIVES OF THE RESEARCH: � The general objective of the research is to investigate the key processes, interactions, inputs and interpretation of the system outputs � The specific objectives of the research are: � Investigate inflow estimation techniques � Investigate sources of uncertainty, the significance and propagation in operational hydrology � Bring the issue of risk into the operation of multipurpose water resource projects � Investigate approaches to improve the operation of water resources systems to ensure infrastructural sustainability, dam safety and operational reliability � To get an overview of uncertainty propagation and risk in operations of water resources systems Mulugeta, UNCERTAINTY PROPAGATION AND RISK ANALYSIS IN WATER RESOURCE SYSTEM…
5 3. SHUFFLED COMPLEX EVOLUTION ALGORITHM (SCE-UA): � A shuffled Complex Evolution algorithm has been implemented for HBVPINE hydrological model, which will be applied for the research � SCE-UA was Developed by Qingyun Duan at the Department of Hydrology and Water Resources, University of Arizona, 1991 � It combines the strength of CRS algorithm with concept of competitive evolution � General purpose global optimization program Mulugeta, UNCERTAINTY PROPAGATION AND RISK ANALYSIS IN WATER RESOURCE SYSTEM…
6 � Shuffled Complex Evolution (SCE) Algorithm ( Duan et al (1992 ): � A method for finding Global Optimum � Random Parameter Sets as a starting point and then allowed to ‘evolve’ over successive iterations (Simplex Method) � Ranking and Shuffling Containing ‘better’ and ‘worse’ points (New parameter Set) � The shuffling in SCE allows Global information about the response surface to be shared which makes the algorithm responsive to the presence of multiple local optima. � The procedure continues until a Global Optimum fitness is reached; Figure SCE Mulugeta, UNCERTAINTY PROPAGATION AND RISK ANALYSIS IN WATER RESOURCE SYSTEM…
7 x1 x2 x3 x4 x5 x6 x7 x8 x9 x10 x1 x3 x5 x7 x9 x2 x4 x6 x8 x10 Figure-2-1: Flow chart of SCE-UA Method, Source: Duan Q.Y., et al, 1992 Mulugeta, UNCERTAINTY PROPAGATION AND RISK ANALYSIS IN WATER RESOURCE SYSTEM…
8 Figure-2-2: Flow chart of the Competitive Complex Evolution (CCE) strategy, Source: Duan Q.Y., et al, 1992 Mulugeta, UNCERTAINTY PROPAGATION AND RISK ANALYSIS IN WATER RESOURCE SYSTEM…
9 � Simplex Procedure: � Reflection � Expansion � Contraction � Shrinking Mulugeta, UNCERTAINTY PROPAGATION AND RISK ANALYSIS IN WATER RESOURCE SYSTEM…
10 4. Implementation of SCE-UA Algorithm for HBVPINE: SCE-UA • Setting initial P. value • Parameter Sampling HYDROLOGICAL MODEL (HM) • Triggering the HM • Sorting SP • Partitioning Model • Evolving Parameters • Sorting & Replacing ? ? Convergence Model Criteria No Outputs Global Optimum Model Yes Parameters Figure-3: Flow Chart-Implementation of SCE-UA for HBVPINE Mulugeta, UNCERTAINTY PROPAGATION AND RISK ANALYSIS IN WATER RESOURCE SYSTEM…
11 i. Global Parameter and Parameter Space – Initial Simulation without screening Figure-4: Output from HBV-SCE tool (17 Parameters) Mulugeta, UNCERTAINTY PROPAGATION AND RISK ANALYSIS IN WATER RESOURCE SYSTEM…
12 ii. Parameter Space – Simulation with screening Figure-5: Output from HBV-SCE tool Mulugeta, UNCERTAINTY PROPAGATION AND RISK ANALYSIS IN WATER RESOURCE SYSTEM…
13 iii. Global Optimum Parameter Value Figure-6 : Output from HBV-SCE tool Mulugeta, UNCERTAINTY PROPAGATION AND RISK ANALYSIS IN WATER RESOURCE SYSTEM…
14 iv. Parameter Interaction and Correlation Studies Figure-7: Output from HBV-SCE tool Mulugeta, UNCERTAINTY PROPAGATION AND RISK ANALYSIS IN WATER RESOURCE SYSTEM…
15 5. What is Next? • Extensive study of the regional pattern of model parameters • Develop approaches for transferring model parameters to Ungauged catchments • Investigate the nature and propagation of uncertainty on the model output 6. Comment: • The SCE-UA algorithm is a general purpose global optimization procedure, could be useful for similar problems • The implementation is relatively easy • Has been used widely , has research outputs and references Mulugeta, UNCERTAINTY PROPAGATION AND RISK ANALYSIS IN WATER RESOURCE SYSTEM…
16 THANK FOR YOUR ATTENTION!! Mulugeta, UNCERTAINTY PROPAGATION AND RISK ANALYSIS IN WATER RESOURCE SYSTEM…
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