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2020 Eugene Wastewater Master Plan Chapter 1: Introduction and Summary 2 <br />The combined wastewater system discharged untreated wastes to the Willamette River until about <br />1950, when the first Eugene primary wastewater treatment plant was constructed on River Avenue. <br />Between 1960 and 1970, separate stormwater and wastewater systems were constructed, and most of <br />the direct stormwater inflow from street and alley drainage was removed from the wastewater system. <br />In 1977, Eugene, Springfield, and Lane County jointly formed the Metropolitan Wastewater <br />Management Commission (MWMC) to develop a regional wastewater treatment system for the Eugene- <br />Springfield Metropolitan Service Area. The new plant on River Avenue was completed in 1984 and was <br />designed to process a peak wet weather flow of 175 MGD. The regional system, which comprises the <br />system components that serve both Eugene and Springfield, also includes the larger pipes and pump <br />stations in the wastewater collection system as well as facilities to treat solid wastes (biosolids) and <br />irrigate effluent for agricultural purposes. <br />Between 1980 and 1999 major collection system expansion occurred. Approximately 32 percent of the <br />local wastewater system was built during this period. In 1992, the Urban Sanitary Sewer Master Plan <br />(USSMP) was adopted to inventory the existing system and provide data and analysis for planning, <br />designing, rehabilitating and managing Eugene’s wastewater collection system. <br />As of 2019, Eugene owned and operated 717 miles of wastewater collection lines. The local system also <br />includes approximately 20,000 manholes and 27 local pump stations. <br />SUMMARY OF CONCLUSIONS <br />While the basic layout for a wastewater collection system is simple enough, the complexities of the <br />system arise almost immediately. How large should the pipes be? How deep? Can the system be <br />expanded to accommodate new development? What if portions of the system can’t flow by gravity to <br />the outfall? What is the condition of the collection system, and how long will any particular pipe last <br />before it needs to be rehabilitated? The Wastewater Master Plan strives to answer the question, “what <br />should be built and when?" <br />For example, if a particular wastewater pipe can no longer convey the volume of wastewater demanded <br />of it, it must be replaced with a larger diameter pipe, or a second parallel pipe must be built. If that <br />larger pipe is sized to handle only current flows it will need to be replaced a second time when <br />additional development occurs. A more cost-effective solution is to replace the pipe once using a larger <br />pipe that may be underutilized in the short term but is adequate for planned developments within the <br />planning horizon. <br />In general, the master plan focuses on providing objective data that can be further analyzed and inform <br />decision making. The data also support several conclusions, which are summarized below: <br />• Chapter 2 indicates that the City anticipates an increase in population, commercial land use, and <br />industrial land use in every major wastewater basin. <br />• As stated in Chapter 3, effective 2017 the City has taken ownership and maintenance <br />responsibilities for all wastewater lines within the public rights of way, which includes more than <br />60,000 lateral lines.