02-11-2019 Council Packet - Laserfiche WebLink

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CMP Part 4B. Sanitary Sewer Plan City of Orono Community Management Plan 2020-2040 Part 4B, Page 10 or will be provided with municipal sewers to solve neighborhood problems or to protect the lakes, but no other urban services are planned for these areas. Table 4B-9: Septic (MCES Unsewered) Projections 2010 2020 2030 2040 Population 3008 2950 2630 2760 Households 1046 1095 1105 1115 Employment 0 0 0 0 Institutional Systems 5 5 5 5 Residential Systems 1041 1090 1100 1110 City Of Orono Projections Table 4B-9 also projects the number of Institutional and residential systems for 2010, 2020, 2030, and 2040. INFLOW AND INFILTRATION General Inflow is water, typically stormwater, which enters the sewer system through broken manhole covers, sewer cleanouts, sump pumps, foundation drains, and rain leaders. Infiltration is water, typically groundwater, which leaks into the sewer system through cracks in the sewer mains, laterals, joints, and manholes. Water from inflow and infiltration (I/I) can consume available capacity in the wastewater collection system and increase the flow into treatment facilities. In extreme cases, the added flow can cause bypasses or overflows of raw wastewater. This extra flow also requires a larger capacity in the city’s collection and treatment components, which results in increased capital, operation and maintenance, and replacement costs. As a sewer system ages and deteriorates, I/I can become an increasing burden on a City’s system. Therefore, it is imperative that I/I be reduced whenever it is cost effective to do so. The MCES has established I/I goals for each community discharging wastewater into the Metropolitan Disposal System (MDS) based on average day flows and allowable peaking factors. In February 2006, the MCES began an I/I Surcharge Program which requires communities within their service area to eliminate excessive I/I over a period of time. Now, communities that exceed their wastewater flow program year goals, will be required to complete an I/I mitigation assignment that will be required to be implemented in 2018. Nonetheless, flow metering data is available for the meter sheds within Orono, and an analysis of this data as it relates to I/I is presented on the following page. The City’s strategies, programs, investments, and goals for reducing I/I are listed in this section as well Municipal I/I Reduction Much of the City’s sewer infrastructure is over 40 years old, and susceptible to I/I due to their age. In addition much of the city system runs along lake shore and is susceptible to high water periods.