05-29-07 Item 7C, Infiltraton and Inflow Study

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1&1 5/24/2007 Page 4 Task 1: Data Gatherine: & Evaluation: Review Mapsl Datal MCES Flow Records Collection and review of existing City & MCES sanitary sewer data; including water consumption records, sanitary sewer maps, storm sewer maps, lift station pump details, pump run time records, sanitary sewer televising reports, City maintenance and reconstruction records, records of system backups, and any additional background data. Task 2: Develop Meterine: Proe:ram to Isolate Flows The Arden Hills sanitary sewer system includes more than 42 miles of pipe. With a system of this size, it is important to subdivide the task into smaller pieces to isolate the system into manageable areas for study. The majority of the system will be divided into sub-districts at the consultant's determination, and flow meters will be installed to monitor flows. Task 3: Source Identification Effort Through the metering effort, the consultant will identify possible sources of the system VI and attempt to isolate the sources to some of the subdistricts of the system. The method of source identification will depend on the anticipated sources of the VI. One or more of the following source identification methods may be used in any or all of the sanitary sewer sub-districts: . Smoke testing (If needed, includes additional cost to paid for directly by the City) . Physical inspection of manholes (To be performed by City staff with consultant direction) . Internal television inspection (If needed, includes additional cost to be paid for directly by the City) . Sump pump inspection program (If this is identified as a source of VI, staff will evaluate how to proceed, with consultant direction) Task 4: Report Preparation The consultant shall prepare a report to formally present the findings of the work in a format that can be presented to the City Council. It is anticipated that City staff will present the findings to the City Council. The report will present a summary of the data gathered, VI sources and problem areas identified based on the work completed, conclusions concerning the potential for effective rehabilitation of possible VI sources, and recommendations for the next phases of the VI reduction effort. There are many rehabilitation procedures and methods available to address identified defects. The appropriate procedure is determined by considering the type of defect, its location and access, and the cost and benefits of rehabilitation. Identified defects will be prioritized. FINANCIAL IMPLICATIONS This is specialized work; therefore, we solicited five consulting companies to provide us proposals to complete the study. We received four proposals for this work, from Bonestroo, Bolton & Menk, Inc., SEH, Inc., and WSB & Associates. Amounts proposed are below: Arden Hills Roseville Bonestroo $9,600 $ I 6,500 Bolton & Menk $20,118 $30,624 SEH $55,304 $75,940 WSB $18,116 $20,923