CHANCE CONSTRAINED WATER QUALITY MANAGEMENT MODEL FOR RESERVOIR SYSTEMS

ABSTRACT

Operation of reservoir systems to comply with water quality criteria is becoming an important management goal. A methodology is developed for optimal short term operation of reservoir systems to control the downstream water quality, using Genetic Algorithm based linked simulation optimization. The single objective management model minimizes the deviation of storage at the end of a management time step from the specified target storage, while maintaining the downstream flow requirements. The optimization model incorporates the uncertainties in prediction of inflows to the reservoir. The cumulative distribution functions of inflows are incorporated as an approximated distribution function in the optimization model and are used to define chance constraints with associated reliabilities. Performance of the developed GA based linked simulation optimization model is evaluated for an illustrative application. Performance evaluation results show that the developed methodology is capable of evolving optimal release strategies to satisfy water quality requirements downstream of the reservoir.

KEY WORDS:

• Reservoir operation
• Chance constraint
• Water quality management
• Genetic Algorithm