Risk minimization in water quality control problems of a river system

Ghosh, Subimal and Mujumdar, PP (2006) Risk minimization in water quality control problems of a river system. In: Advances in Water Resources, 29 (3). pp. 458-470.

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Abstract

Methodologies are presented for minimization of risk in a river water quality management problem. A risk minimization model is developed to minimize the risk of low water quality along a river in the face of con.ict among various stake holders. The model consists of three parts: a water quality simulation model, a risk evaluation model with uncertainty analysis and an optimization model. Sensitivity analysis, First Order Reliability Analysis (FORA) and Monte-Carlo simulations are performed to evaluate the fuzzy risk of low water quality. Fuzzy multiobjective programming is used to formulate the multiobjective model. Probabilistic Global Search Laussane (PGSL), a global search algorithm developed recently, is used for solving the resulting non-linear optimization problem. The algorithm is based on the assumption that better sets of points are more likely to be found in the neighborhood of good sets of points, therefore intensifying the search in the regions that contain good solutions. Another model is developed for risk minimization, which deals with only the moments of the generated probability density functions of the water quality indicators. Suitable skewness values of water quality indicators, which lead to low fuzzy risk are identi.ed. Results of the models are compared with the results of a deterministic fuzzy waste load allocation model (FWLAM), when methodologies are applied to the case study of Tunga-Bhadra river system in southern India, with a steady state BOD-DO model. The fractional removal levels resulting from the risk minimization model are slightly higher, but result in a signi.cant reduction in risk of low water quality.

Item Type:	Journal Article
Publication:	Advances in Water Resources
Publisher:	Elsevier BV
Additional Information:	The Copyright belongs to Elsevier BV.
Keywords:	Fuzzy sets;Optimization models;Uncertainty analysis;Waste management;Water quality
Department/Centre:	Division of Mechanical Sciences > Civil Engineering
Date Deposited:	17 Feb 2006
Last Modified:	19 Sep 2010 04:22
URI:	http://eprints.iisc.ac.in/id/eprint/5108

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