Optimal Flood Control Operation for a Multireservoir System
Date Issued
2006
Date
2006
Author(s)
Wei, Chih-Chiang
DOI
en-US
Abstract
The objectives of this study are: (1) development of the real-time flood control model for a multipurpose multireservoir system, and (2) building of methodology for extracting the optimal reservoir release rules for flood control. Based on the real-time model and the extracted release rules, the on-going release amounts obtained can be provided as a reference amount when operators making release policy.
To address the real-time release problem for a multireservoir flood control system, this study presents and compares two operation strategies. Strategy 1 is the real-time joint reservoir operations without using the balanced water level index (BWLI) method, while Strategy 2 involves real-time joint reservoir operations using the BWLI method. The two presented models (strategies) are formulated as mixed-integer linear programming (MILP) problems. For the model of Strategy 2, the four objectives are (1) minimizing the maximum water level at the selected control points during flood, (2) minimizing the reservoir maximum release during flood, (3) minimizing the maximal target storage error during the specific time interval at the flood ending periods, and (4) minimizing the difference between the WLIs of the two specific reservoirs in a multiple reservoir system; the constraints include reservoir continuity, physical limitations and institutional constraints, river routing, and constraints from the BWLI method. The optimal real-time model is selected from the two strategies based upon good performance and is verified by comparing with historical records.
To develop a set of optimal operating release rules for flood control, the proposed methodology is used to extract the operating rules (decision trees). The steps within the methodology include the following: (1) collection of data, (2) building of flood database, (3) generation of optimal input-output patterns by running the deterministic flood-control optimization model, (4) classification of training and testing data, (5) extraction of tree-based release rules (decision trees) for designed scenarios by using the decision-tree algorithm, (6) determination of optimal tree-based rules, and (7) verification of optimal tree-based rules through comparisons with both regression-based rules derived from multiple-linear regression model and existing release rules.
The study case is the Tanshui River Basin system in Taiwan. The collected data of 36 typhoons (1987–2004) are used for the use of the presented both real-time model and method of extracting rules. The results are described as follows.
(1) For real-time model, comparing the results obtained from the two strategies reveals that Strategy 2 performs much better than Strategy 1 in determining the reservoir real-time releases throughout the system during flood emergencies in order to minimize flooding, while maintaining all reservoirs in the system in balance if possible. Consequently, the proposed model using the BWLI method demonstrates its effectiveness in estimating on-line releases.
(2) For extracting rules, the separate tree-based rules in Shihmen and Feitsui Reservoirs are established. Results demonstrate that the solution using the tree-based rules have better performance than the regression-based rules and the existing rules in terms of reducing the peak water table at the downstream control points, and meeting the target reservoir storage at the end of flood. Moreover, this study proposes an approach for revising the existing rules according to the derived tree-based rules.
This study has successfully accomplished in formulating real-time flood-control operation model and in extracting optimal release rules in a multipurpose multireservoir system.
Subjects
防洪
多水庫
優選
決策樹
flood control
multireservoir
optmzation
decsion tree
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-95-D89521007-1.pdf
Size
23.31 KB
Format
Adobe PDF
Checksum
(MD5):8a2823efc9132f44cc36bfc4ca790119