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Memorandum <br />� Bones�roo <br />T0: KRIS GIGA & GREG HOAG PROJECT: ill A5SIS7ANCE PROJECT QATE; �iI�I2Q OS 2335 Highway 36 W <br />St Paul, MN 55113 <br />FROM: CHUCK JANSKI CLIENT: CITY OF ARDEN HILLS TeE 651-636�60Q <br />Fax 651-636-1311 <br />RE: I�I PLAN AN� DRAFT SCFiEDULE Fi�E No: 00353-07103-0 www.bonestroo.com <br />Problem: The City of Arden Hills is faced with an annual $100,100 s�archarge from the MCES due to <br />infiltration/inflow levels which exceed the MCE5 allowable peak fiaw rate for the community <br />Goal: The goaf of the program is to identify and remo�� sufficient I�T ta eliminate the current T/I surcharge <br />and reduce the annual treatment cost paid to the MCES. <br />Appraach: The approach will include an initial "big picture" review of the current situation, folfowed by more <br />detailed investiga�ions, data evaluation, rehabilitation and then Iong term follow-up. The plan provides a <br />basic guidefine far the anticipated project, but it must be flexible to adjust directian in response to actua[ <br />situations or defects that accur or are identiFied during the course of the work. Rehabilitation is the step <br />that actually removes sources of I/I and should be consideret! an on-going task during �he project. <br />1. Initial r�view consists of compiling MCES ffow data, city maps, city investigation records, fift station <br />data, connection data, building type information, <br />A. Review MCES Flow data and precipitation data to understand MCES determination of peak <br />flow le�els <br />B. Review City Maps io understand sewer flaw patterns, high ground water areas, areas where <br />sanitary sewers are "off roadways" or on easements� [ift station locations and servic� areas, <br />C. Discuss and summarize Gity investigation effo�ts to further understand conditions of the <br />sani�ary sewer system <br />D. Compile lift statian pump data and review pump running times tfl determine �ariations <br />during wet weather conditions <br />E. Coliecf number af buifdir�g connections and types of buildings per drainage areas for data <br />evaluation and �urther understanding of the system <br />2. Analyze MCES flow data with respect to other system ir�formation to de�elo� "plan" for additianal <br />investigation e�Forts. <br />3. Identify locations for additional fEow monitoring to further subdivide the collection systern and <br />identify areas with little or no I/I flow. This will focus effor�s on those areas that actually contribute <br />to the I/I peak situation. <br />4. Collect flow cfata and review "flow respons�" to rainfall events. <br />A. The MCES data shou�d be regularly coliected and reviewed to monitar results of the <br />rehabiEitation efForts and determine benefits of the work. <br />g. Temporary flow metering (in manhofes} is typically a short term iask to identify sub-areas <br />requiring more or less investigation or rehabilitation efForts. The effectiveness of the <br />temporary metering is dependent on rainfall events. <br />C. The City lift station can also be used to monitor flows within their individual service areas. <br />Each station is equip�ed with a"r�n time" meter that records the number of hours that each <br />pump runs. These hourly data can be used in conjunction with the calibrated pu�-nping rate <br />��Metro-inet�ard�nhills�PR&PV4I�E�gineering�1&1�6.9.08 Council Update�City_CRJ^Memorandum re II Plan Ob 04 2408.doc <br />