INTERIM SERVICING STRATEGY STUDY FOR VAUGHAN'S NEW COMMUNITY AREAS
The City retained Civica to complete an Interim Servicing Strategy (ISS) study to develop servicing strategies with risk management measures to safely accommodate future developments within existing sewer infrastructures on an interim basis before the Regional trunk sewer becomes available (in 2028 and beyond). The work included the collection of existing data; analysis of data to establish dry and wet-weather flow peaks, volumes, and patterns; hydrologic and hydraulic modeling utilizing Info Works ICM; investigating the capacity of selected outlets under existing, approved, and future conditions; and developing risk management solutions for the interim condition. The existing residual capacity in the sewers was calculated using monitored flows and a detailed pipe-by-pipe hydraulic model of the system. Analysis of the monitored flows provided input to existing development flow generated during large storms while the model predicted the hydraulic performance of the sewer system under these critical flows. The calibrated model was used to analyze available residual capacities within outlet sewers to accommodate interim future developments. Three (3) development scenarios were defined and analyzed under the City’s 1 in 25-year design storm to assess the performance of the sanitary sewer system downstream of the new developments. For the outlets to accommodate the future population with an acceptable level of service (i.e., free flow or minor surcharge), risk management measures were proposed, including monitoring and inspections, new development standards, I&I reduction measures, phasing, flow attenuation, and pipe replacement.