Alternate formulation of time as a decision variable to facilitate real-time operation of water supply systems

With the advent of a new focus on energy conservation and the availability of cost efficient computer technology, many water utilities are investigating new ways to improve the efficiency of their water distribution system operations. Of particular concern is improved operation of the pumping facilities since pumping generally accounts for a large fraction of the total operating costs. One way to improve such operations is through the use of optimally generated pump schedules. Optimal pump schedules may be generated using some type of optimization approach coupled with a physical description of the water distribution network. Where the distribution system can be characterized as a serial configuration, dynamic programming can be efficiently applied to generate an optimal control policy. When the system is nonserial, an optimal control policy may be obtained through the use of dynamic programming coupled with a spatial decomposition scheme or through the application of nonlinear programming.