Once a calibrated model is complete it also prudent to consider the state guidelines for collection system design. There are many factors that affect the peak flows in a collection system. Because of this fact, the Utah Administrative Code (UAC) R317 outlines a design criterion for sanitary sewer flows of 100 gpcd with a peaking factor of 2.5 for all sewer interceptors. These flows were compared with calibrated model flows and are shown as "Existing (100 gpcd)" in green in the calibration graphs in Figure 5-2 below and Appendix B.
It was determined by the City to establish the Level of Service (LOS) based on the UAC R317 design criterion for the existing sanitary sewer system. The existing flow in the calibration graphs represent the flows that could occur in the collection system based on the LOS the City has established for sizing its sewer collection pipes.