Municipal Water Planning—Mixed Integer Approach

The mixed integer programming approach to selection of municipal water source-facility combinations overcomes many of the limitations of linear programming. The mixed integer concept allows separation of capital investment and operating costs for detailed analysis of the least cost of insuring desired level of service. Standard of pipe and equipment require discrete, not continuous variables. Chance constrained programming allows uncertainty in both supply and demand to be considered in the model. An optimizing algorithm based upon the Branch Bound concept of mixed integer programming selects the optimum combination of source-facilities from all possible alternatives. The procedure is demonstrated by developing a model for an example problem and the optimum solution is given.