Res 2016-137/approving a Water Master Plan to guide the future maintenance and extension of the City’s Water Infrastructure

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Alan Plummer Associates, Inc. Water Master Plan Update 2016 was approximately 3,520 gpm (5.07 MGD) during the calibration period. While this percentage is higher than average for the City, water restrictions and lower overall usage may be increasing the percentage loss and the actual magnitude of the losses may not be appreciably different. The City is investigating the causes of increased water loss in the system and trying to determine if they are real or apparent water losses. AMI is a good tool in this effort, but cannot help when the source of loss is unmetered, unaccounted for water. 3.3 CALIBRATION While many model calibrations are considered adequate if 24 or 48 consecutive hours of system operation can be simulated to within 10 percent of available data for pressures, tank levels, and pump flow rates, APAI decided to utilize a 72-hour calibration period and strive to improve the simulation error such that most modeling results are within 5 percent of the available supervisory control and data acquisition (SCADA) system data. The available AMI data made these targets quite reasonable. Appendix A describes the hydraulic model calibration process in detail. A summary of the calibration results follows. In general, most pressure data was simulated to within 5 percent of measured values, while all stations were simulated to within 10 percent of SCADA data for the entire 72-hour calibration period. With respect to tank levels, simulations were quite accurate with respect to both cycle times and timing of peak and trough levels. Pumping simulations were also very accurate, as simulated flow rates at all stations where flow metering was available match the SCADA data to within 5 percent at nearly all times during the simulation. Appendix A contains a plot of every pressure node, pump, valve, and tank for which comparisons were made to collected SCADA or pressure data recorder data. The following figures show example plots of each type of calibration. 3-2 m:\projects\0600\022-01\doc\report\draft\draftmasterplan-v15_hef.docx