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Roseville Public Works, Environment and Transportation Commission Agenda Item Date: June 26, 2018 Item Description: Inflow and Infiltration (I&I) Study Update Background: Item No: 5 The majority of Roseville's sanitary sewer system was constructed between 1950 and 1960, along with most of the current housing stock. The City's sanitary sewer system includes more than 145 miles of collector sewers and 13 lift stations. Within the City limits, the Metropolitan Council Environmental Services (MCES) owns and operates more than 12 miles of interceptor sewer. Wastewater treatment for the City is provided by the MCES at the Metro (Pig's Eye) Plant located in St Paul. The City of Roseville is billed by the MCES for the use of the interceptor sewer system and treatment of the wastewater at the Metro Plant. The City's wastewater flow is determined by the MCES through a relatively complex formula based on the flow records from eight separate meters. A master meter (No. 46) is located at the southern edge of the City near Lake McCarrons. The flow records from this meter are adjusted by subtracting the flow rates from six other meters that measure flows into Roseville from Shoreview (two meters), Arden Hills (three meters) and St Anthony (two meters). On March 13, 2017, City Council awarded a contract for Engineering Services to complete an Infiltration and Inflow Study for the City of Roseville. The study encompassed the entire City. The data collected from the study allows the City to use flow data to quantify the effectiveness of the City's sanitary sewer lining and other I/I mitigation efforts. Further, the results helped identify areas in the City that have excessive I/I so the City can prioritize other mitigation options such as sump pump disconnections. Owning some of the meters will allow City staff to measure flows in certain areas for an extended period. This will allow us to better analyze the UI in the City over time and will also allow us to gather better overall data if certain years have a lack of rainfall and therefore a lack of data. Year one of the study has been completed. The data has been collected, analyzed, and a report has been generated. Recommended Action: Receive presentation and ask questions/provide comments. Attachments: A. Presentation B. Resident Resources