An Operational Scheduling Framework for Tanker-Based Water Distribution Systems under Uncertainty

Abstract

Tanker water systems play a critical role in providing adequate service to meet potable water demands in the face of acute water crisis in many cities globally. Managing tanker movements among the supply and demand sides requires an efficient scheduling framework that could promote economic feasibility, ensure timely delivery, and avoid water wastage. However, to realize such a sustainable water supply operation, inherent uncertainties related to consumer demand and tanker travel time need to be accounted in the operational scheduling. Herein, a two-stage stochastic optimization model with a recourse approach is developed for scheduling and optimization of tankerbased water supply and treatment facility operations under uncertainty. The uncertain water demands and tanker travel times are combinedly modeled in a computationally efficient manner using a hybrid Monte Carlo simulation and scenario tree approach. The maximum demand fulfillment, limited extraction of groundwater, and timely delivery of quality water are enforced through a set of constraints to achieve sustainable operation. A representative urban case study is demonstrated, and results are discussed for two uncertainty cases: (i) only demand and (ii) integrated demand-travel time. The value of stochastic solutions over the expected value and perfect information model solutions are analyzed and features of the framework for informed decisionmaking are discussed.