Operating Rules for Joint Operation of Raw Water Sources

The techniques of linear programing, synthetic streamflow generation, and simulation are merged to derive operating rules for a multiple source water supply. The approach is general; it is here applied to the Baltimore water supply, where upland reservoirs furnish water by gravity flow, and a backup supply delivers pumped water from the Susquehanna River. The reservoir water is essentially free but subject to random storage fluctuations, whereas the backup supply has constant availability but a high operating cost. The algorithm assumes reservoir release to be a linear function of available storage at the beginning of a period. Chance constrained linear programing is employed to select candidate operating policies which are subsequently tested by a simulation program for long‐term performance. Results indicate that substantial savings can be effected with concurrent frequent improvement in system performance, when compared with operation under a constant reservoir draft policy.