City of Morgan Hill Sewer System Master Plan 2017

that, while not deficient, may be approaching full capacity. Deficient pipelines are highlighted in red on the figure and discussed as follows: x Vineyard Boulevard from La Cross Drive to Monterey Road. This segment experiences d/D ratios above 0.9. x Hale Avenue from Longview Drive to Main Avenue. This segment experiences d/D ratios under 0.5 excepting one portion experiencing a d/D ratio above 0.9. 7.2.2 Existing Peak Wet Weather Flows Capacity Evaluation The wet weather flow analysis is intended to document the impact of rainfall events on the existing system, and to identify the improvements necessary to limit sanitary sewer overflows. The design criteria for wet weather events allows pipeline surcharging in the manhole to within three feet of the rim elevation. The hydraulic analysis indicates two areas of deficiencies, as shown on Figure 7.2 , and documented in the following: x Monterey Road from Main Avenue to approximately Cosmo Avenue. This segment experiences surcharging conditions where the hydraulic grade line raises within 3 feet of the rim elevation. x La Cross Drive from La Grande Drive to Monterey Road. This segment experiences surcharging conditions within 3 feet of the rim elevation until it reaches Vineyard Boulevard. From Vineyard Boulevard, the segment of pipeline experiences d/D ratios above 0.9. 7.3 ULTIMATE BUILDOUT CAPACITY IMPROVEMENTS The system performance and design criteria summarized on Table 3.1 , was used as a basis to evaluate the capacity adequacy of the existing sanitary sewer system. The design flows simulated in the hydraulic model for the General Plan buildout were summarized on Table 5.4 and are documented as follows: x Buildout PDWF = 8.0 mgd x Buildout PWWF = 10.5 mgd x Sewer pipelines are recommended to serve future growth inside the City and increase the reliability of the sewer collection system as well. The proposed capacity improvements for the sanitary sewer system are listed on Table 7.1 . This table lists the master plan assigned improvement number (e.g,HM-P1), along with other relevant information including alignment description, pipe size, and pipe length. The improvement number is further defined in the Capital Improvement Program chapter (Chapter 8). The improvements are described in detail on the following pages and shown on Figure 7.3 .

August 2017

7-4

City of Morgan Hill Sewer System Master Plan