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7.a. I-I Presentation Handouts2/15/2012 1 Inflow & Infiltration Local Mitigation Efforts Inflow & Infiltration Local Mitigation Efforts Jeff Oliver P.E., City Engineer Dave Lemke, Utility Maintenance Supervisor Golden Valley’s I / I Problem Golden Valley’s I / I Problem •Notified of peak discharge in 2005 •Surcharge Implications $$$ •Meter change out –sump pump inspections •Performed 2005 I/I Study JO I / I StudyI / I Study •City wide problem •Recommendations –Strengthen Sanitary Sewer Ordinance –Implement service lateral inspection/repair program –Continue “drain tile” service program –Continue inspection/repair program on City system JO 2/15/2012 2 Golden Valley’s I/I Reduction Strategy Golden Valley’s I/I Reduction Strategy •Three-pronged approach –MCES(8 miles of pipe) –City(113 miles of pipe) –Private Laterals(147 miles of pipe) •Willingness to modify & improve process over time JO Focus of Today’s Discussion Focus of Today’s Discussion •Private System & City System –Ordinance (Jeff) –Point of Sale inspections (Dave) –Ongoing maintenance efforts (Dave) –Pavement Management Program (Jeff) JO Ordinance RevisionsOrdinance Revisions •Staff recommendation to Council –Develop process to address private system –Develop approach based on: •Plumbing permits •Planning actions •Direction from Council –Implement Point of Sale program –Include plumbing permits & planning actions JO 2/15/2012 3 Point of SalePoint of Sale Implementation of a service lateral inspection/repair program Implementation of a service lateral inspection/repair program SECTION 3.31 CERTFICIATE OF INFLOW AND INFILTRATION (“I&I”) COMPLIANCE Subdivision 1. Required.No person shall sell, advertise for sale, give or transact a change in title or property ownership of real property with one or more buildings or structures, without first obtaining a certificate of I&I compliance from the City or complying with Subd. 5 hereof. DL Point of SalePoint of Sale •Public and realtor notification of Point of Sale program –Strong realtor opposition –Public education •Sewerfest •Mailings, Newsletter •Cable TV •Meetings with realtors DL Service Lateral Inspection Program Inspection Forms and Correction Notices Service Lateral Inspection Program Inspection Forms and Correction Notices •Inspection costs –$250 residential –$750 commercial DL 2/15/2012 4 Correction notices need to be clear and concise as possible. Correction notices need to be clear and concise as possible. •Service repair costs –Range $500 -$10,000 –Average $3,500 DL Compliance CertificateCompliance Certificate DL Ongoing Maintenance Efforts Ongoing Maintenance Efforts •Replace MH covers •MH Sealing •Televising •Lining mains in areas of concern •Flow monitoring DL 2/15/2012 5 Pavement Management Program Pavement Management Program •1.0 –5.0 miles of streets / year •9” clay pipe, 50+ years old •CCTV evaluation of mains, prioritize JO Pavement Management Program Pavement Management Program •Replacement –sags, broken pipes •Sewer lining –Primary rehab for I/I –Early-2000s –pipe lining, short liners –Mid-2000s –full length liners –50-75% City mains in PMP repaired each year JO Pavement Management Program Pavement Management Program •Reconstruct & seal manholes •Install water tight castings •Drain tile system –sump connections •Voluntary service repair program JO 2/15/2012 6 PMP Lateral Repairs: Evolving process 2006-2011 PMP Lateral Repairs: Evolving process 2006-2011 •2006 private service repairs (service stubs) –Options: New pipe or lining –Liners problematic –Low Participation: 22 of 250 homes •2007 mandatory inspection •2008 private service repairs, voluntary –Participation low due to bids •Inexperienced sewer contractors –Low prices –Substandard repairs •Better way?JO •2010 New voluntary repair program –Pre-qualified contractors –Master contract with City –Assessment option •Resident inspections –Follow POS process –No charge for inspection –Informed decisions PMP Inspections: Evolving process 2006-2011 PMP Inspections: Evolving process 2006-2011 JO How are we doing? Peak flows How are we doing? Peak flows •Long Term Flow Monitoring –MCES allowable peak rate:8.4 MGD –Oct 4, 2005 event:13.8 MGD –2007 wet autumn •No exceedence, no surcharge for GV –May 2011 •Conditions similar to 2005 •Peak hour rate:9.6 MGD •Peak rate lower than expected JO 2/15/2012 7 How are we doing? Total Flows How are we doing? Total Flows JO •8,000 total services in City •5 years of inspection tracking (2007-2011) –36% of services inspected –28% now compliant •Only 10% of services pass first inspection, 90% require some repair How are we doing? Private service compliance How are we doing? Private service compliance JO More work to be doneMore work to be done •Flows from western Golden Valley still a concern •Point of Sale a long-term solution –Lengthened by depressed real estate market JO 2/15/2012 8 Thank YouThank You Questions / Comments