Optimization of regional water distribution system with blending requirements

In a multisource, multiquality regional water distribution system, water agencies often find that it is necessary to impose blending requirements at certain control points in the system in order to secure the desired water quality downstream of the control points. A nonlinear multicommodity flow model is proposed to optimize water delivery in such a system while at the same time meeting the imposed blending requirements. Waters from different sources with different water quality are considered as different commodities concurrently sharing a common distribution system. The model incorporates a set of nonlinear constraints to account for the perfect mixing condition at nodes where waters from multiple sources merge. The proposed model was first tested and verified on a simplified hypothetical system and then applied to a large-scale regional water distribution system in Southern California. The model is steady state and monthly. The results obtained indicate that the proposed methodology can efficiently control water blend in a complex water distribution system while minimizing the total shortage in water delivery.