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REQUEST FOR COUNCIL ACTION Date:03/11/19 Item No.: 9d. Department Approval City Manager Approval Item Description: Approve ProfessionalServices Contract for Flow Monitoring for Inflow and Infiltration Study 1 B ACKGROUND 2 The majority of Roseville’s sanitary sewer system was constructed between 1950 and 1960, 3 along with most of the current housing stock. The City’s sanitary sewer system includes more 4 than 145 miles of collector sewers and 13 lift stations. 5 Within the City limits, the Metropolitan Council Environmental Services (MCES) owns and 6 operates more than 12 miles of interceptor sewer. Wastewater treatment for the City is provided 7 by the MCES at the Metro (Pig’s Eye) Plant located in St Paul. The City of Roseville is billed by 8 the MCES for the use of the interceptor sewer system and treatment of the wastewater at the 9 Metro Plant. 10 The City’s wastewater flow is determined by the MCES through a relatively complex formula 11 based on the flow records from eight separate meters. A master meter (No. 46) is located at the 12 southern edge of the City near Lake McCarrons. The flow records from this meter are adjusted 13 by subtracting the flow rates from five other meters that measure flows into Roseville from 14 Shoreview (two meters), Arden Hills (three meters) and St Anthony (one meter). 15 On March 13, 2017, The City Council awarded a contract to SEH, Inc. for engineering services 16 to performa Comprehensive CitywideInflow andInfiltration (I/I) Study. This study 17 encompassed the entire City. It allowed the City to compare flow data to quantify the 18 effectiveness of the City’s sanitary sewer lining and other I/I mitigation efforts. Further, the 19 results helped identify areas in the City that have excessive I/I so the City can prioritize other 20 mitigation options such as sump pump disconnections. 21 As part of this project, the City purchased 10flowmeters.Owningsome of the meters will allow 22 City staff to measure flows in certain areas for an extended period. Based on the results of the I/I 23 study the City will work with the consultant to install these meters in specific areas in the City 24 that showed increased levels of I/I during the initial study. This will allow us to better analyze the 25 I/I in the City over time, analyze the effectiveness of our I/I mitigation projects and will also 26 allow us to gather better overall data if certain years have a lack of rainfall and therefore a lack of 27 data. 28 On May 7, 2018, The City Council awarded a contract to SEH, Inc. for engineering services to 29 assist with the installation, maintenance, and reporting for the study for the calendar year of 30 2018. Page 1 of 2