City of Morgan Hill Sewer System Master Plan 2017

The trunk then turns south on Monterey Road as a parallel 21-inch and 30-inch to California Avenue, where it consolidates into the Joint Trunk sewer. 4.3 JOINT MORGAN HILL – GILROY SEWER TRUNK The C ity of Morgan Hill’s sewer flows are collected via the major trunk systems described in the previous sections, and ultimately flow is conveyed to the intersection of California Avenue and Monterey Road. At this point, flows enter the Joint Morgan Hill-Gilroy Sewer Trunk, and proceed west on California Avenue to Harding Avenue. From this intersection, flow continues south on Harding Avenue, jogging along Highland Avenue and easements in agricultural lands to the city of Gilroy at Day Road. Flow then jogs through the city of Gilroy and is ultimately discharged to the SCRWA WWTP. The Joint Trunk is maintained by a Joint Exercise of Powers Agreement between the City of Gilroy and the City of Morgan Hill (Appendix A) and dated May 19 th , 1992. This agreement establishes the formation of the South County Regional Wastewater Authority (SCRWA), and includes an exhibit that documents the pipeline capacities and the capacity allocation for each segment of the Joint Trunk. The agreement dictates that a 4.0 MGD capacity allocation exist in the Joint Trunk and a 7.5 MGD capacity reservation in the City of Gilroy trunk system to accommodate Morgan Hill’s flows. There have been several studies since the 2002 Sewer System Master Plan that evaluated the capacity adequacy of the existing Joint Trunk, and the need for construction of the Relief Trunk. The City of Morgan Hill has initiated construction of the Relief Trunk, and is currently in the design-build process to connect the Relief Trunk to the trunk system in the City of Gilroy. 4.4 LIFT STATIONS When routing flows by gravity is not possible due to adverse grades, lift stations are used to pump flows. The City currently maintains fourteen lift stations in the sewer collection system, as summarized on Table 4.2 and shown on Figure 4.5 . Table 4.2 also includes wet well dimensions, capacity, and holding time of each lift station. Only four of the fourteen lift stations were included in the hydraulic modeling effort, and due to their location on major trunk systems. The modeled lift stations are listed as follows: x Lift Station G: This lift station services the area located along Old Monterey and along Sanchez Drive to the west. The lift station is located at 8615 Monterey Road. This lift station includes a duty pump that is rated at 800 gallons per minute (gpm). The pump discharges into an 8-inch force main that heads south along Butterfield Boulevard. x Lift Station H. This lift station services the area that is along Llagas Road, east of Enderson Court, and west of Sanchez Drive. The lift station is located at 320 Llagas Road. The lift station includes a duty pump that is rated at 500 gpm. The pump discharges into a 4-inch force main that heads southeast along Hale Avenue.

August 2017

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City of Morgan Hill Sewer System Master Plan