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Consideration to execute a funding agreement, M10005WA05, with Milwaukee Metropolitan Sewerage District (MMSD) for Sanitary Sewer Dye Water Testing and Flow Data Modeling
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Submitted by:
Chris Jain, P.E., Senior Civil Engineer
Department:
Public Works, Engineering Division
A. Issue
Consideration to execute a funding agreement, M10005WA05, with Milwaukee Metropolitan Sewerage District (MMSD) for Sanitary Sewer Dye Water Testing and Flow Data Modeling.
B. Background/Options
The City invests significant municipal and MMSD funds in sewersheds throughout the City to reduce "clear water" (inflow and infiltration, or I/I) from entering the sanitary sewer system. I/I occurs in both City-owned mains and private laterals; reducing it supports regulatory compliance and lowers the risk of basement backups during large rain events. Over the past 15 years, the City has completed numerous projects relaying mains and laterals and using rehabilitation techniques such as lateral grouting and Cured-In-Place Pipe (CIPP) lining.
To measure the effectiveness of these investments, City staff will complete two evaluation projects to compare the pre- and post-construction infiltration into the sanitary system. The first project will utilize dye water flooding and CCTV inspections to compare current infiltration rates against historical infiltration rates observed in previous dye water flooding efforts. Dyed water (environmentally safe) is used to fill the storm sewer while CCTV is used to observe and document infiltration into the adjacent sanitary sewer that enters the system through cracks, joints, and laterals.
The second project will analyze several years of flow data collected from MMSD-provided meters installed in manholes around the City. By comparing pre- and post-construction flow data during rain events, the City will quantify and evaluate the reduction in infiltration achieved with the completed sanitary sewer rehab and replacement projects.
The City will iss...
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