Following the design of a new PFAS Treatment plan at Main Street, AKM prepared the Water Master Plan for the City of Tustin in 2023. The City of Tustin provided water service to an 8.6-square-mile area with a population of approximately 80,000 residents. Prior to the detection of PFAS contamination in the groundwater supply, the City’s water demand was met primarily by wells (77%), with imported water supplementing the remaining 23%. To assess system performance under both existing and future conditions, AKM developed a comprehensive hydraulic model of the City’s water distribution system. The completed system model included 183 miles of water mains, seven storage reservoirs, nine wells, 1,907 fire hydrants, and five booster pump stations. The model’s base demand data was developed using meter consumption records and production purchase data. These demands were refined based on meter readings collected during the calibration period, while diurnal demand curves were generated using SCADA records and integrated into the model. To validate calibration accuracy, AKM collected data from field-installed pressure loggers and SCADA system records, capturing facility flows and pressures. Additionally, fire flow tests were conducted and incorporated into the model to further verify its accuracy. A range of operational scenarios was analyzed under both existing and future conditions to identify system deficiencies. Deficiencies were primarily found in areas with low pressure or insufficient pipeline looping, where fire protection requirements could not be met. AKM developed and tested alternative solutions within the model to mitigate these deficiencies. Recommended system improvements were then prioritized based on their benefit to system reliability and operational efficiency.
Further analysis was conducted to evaluate system reliability under different operating conditions. Scenarios included removal of a major transmission main on Newport Boulevard, closure of all imported water connections with all existing wells routed to the future PFAS Treatment Facility, zonal boundary analyses, and reservoir outage simulations. The model was used to identify potential pressure issues and assess water conveyance impacts, helping to develop contingency plans for each scenario. The model will continue to serve as a valuable tool for future operational planning, especially as the new PFAS Treatment Plant is brought online and new system controls are implemented.

As part of the master planning process, reservoirs, pump stations, wells, and treatment plants were assessed for physical condition and historical operational issues. Improvement projects were recommended based on these assessments, incorporating feedback from operations and maintenance staff.

A comprehensive Capital Improvement Plan (CIP) was developed to complement the City’s existing infrastructure improvement list. The CIP prioritized projects based on system reliability, deficiency severity, and budget constraints, while also aligning with the City’s long-term infrastructure goals.