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<br />. <br /> <br />~ <br /> <br /> <br />~ <br />EN HILLS <br /> <br />MEMORANDUM <br /> <br />DATE: <br /> <br />July] 0,2006 <br /> <br />AGENDA ITEM 7.A <br /> <br />TO: <br /> <br />Mayor and City Council <br />Michelle Wolfe, City Administrator <br /> <br />Kristinc Giga, Civil Engineer ~ <br /> <br />FROM: <br /> <br />SUBJECT: <br /> <br />Inflow and Infiltration (1&1) Update <br /> <br />BACKGROUND <br /> <br />. <br /> <br />City stall met with the Metropolitan Council lor Environmental Services (Met Couneil/MCES) <br />in Fcbruary to discuss the current problcm with inflow and infiltration (1&1). Based upon current <br />data and conditions, the City could face a $500,500 surcharge with Mct Couneil if 1&1 is not <br />rcdueed. This charge would be paid over live years, starting in 2007, but would be rehievable if <br />the City spent any money to rcduce 1&1. The City could receivc a surcharge adjustment by <br />submitting an application for crcdit [()r work to be done in 2007 with defined 1&1 project work or <br />non-specific projects. Staff is investigating what nceds to be done to reduce the surcharge and is <br />estimating eosts of the nccessary improvements. Staff is also gathering information from past <br />O&M procedures and projects that could be uscd as to assist in 1&1 reduction as well. <br /> <br />Met Council has three meters within Arden Hills. Data from thc meter near Round Lake <br />indicated that this area experiences the most 1&] within thc City. O&M teels that leaking <br />manholes are a major sourcc of the 1&1. Therefore, O&M crews have spent time this spring <br />inspecting manholes, filling out manhole reports on the existing conditions and noting needed <br />improvements. City staff has discussed rcpair methods, and it is anticipated that repairs will <br />begin in mid-July. Ncw chimney seals and rings will be placed on manholes which eurrently <br />have deteriorating rings. Low manholes will be raised and manhole covers with open pickholes <br />will be replaced or scaled to prevent water from draining into them. <br /> <br />Sump pumps have been a common source of 1&1 in other cities. When Arden Hills replaced the <br />rcsidential water meters in 1999-2000, sump pumps were also inspected. However, staff is not <br />confident that these inspcctions wcrc successful in disconnecting all of the slimp pumps from the <br />. sanitary sewer system. <br /> <br />\\Mctro-inet.us'.ardenhilbPR&P\V\Fngim'l'ring-2006".CouncjJ Actions\7-10-06 Melllo 1&1 Update. doc <br />