City of Morgan Hill Sewer System Master Plan 2017

peak dry weather flow, 2) peak wet weather flows from storm rainfall Event No. 1, and 3) peak wet weather flows from storm rainfall Event No. 2 The calibrated hydraulic model was used as an established benchmark in the capacity evaluation of the existing sanitary sewer system. The model was also used to identify improvements necessary for mitigating existing system deficiencies and for accommodating future growth. The hydraulic model is a valuable investment that will continue to prove its worth to the City as future planning issues or other operational conditions surface. It is recommended that the model be maintained and updated with new construction projects to preserve its integrity. ES.8 CAPACITY EVALUATION The calibrated hydraulic model was used for evaluating the sanitary sewer system for capacity deficiencies during max day dry weather flows (MDDWF) and max day wet weather flows (MDWWF). The system performance and design criterion was used as a basis to judge the adequacy of capacity for the existing sanitary sewer system. The design flows simulated in the hydraulic model for existing conditions and the general plan buildout include: In general, the hydraulic model indicated that the sanitary sewer system exhibited acceptable performance to service the existing customers during both peak dry weather and peak wet weather flows. Future flows were then added to the hydraulic model and the existing system was expanded in order to serve these future customers. The proposed improvements for the future system are shown with pipe sizes on an overall exhibit on Figure ES.3 . This master plan also included a capacity assessment of the Morgan Hill-Gilroy Joint Sewer Trunk. ES.9 CAPITAL IMPROVEMENT PROGRAM The Capital Improvement Program includes pipeline, lift station, and pipe rehabilitation projects recommended in this master plan ( Table ES.5 ). Each improvement was assigned a uniquely coded identifier associated with its basin, and which is used for locating it on Figure ES.3 . The estimated construction costs include the baseline costs plus 30 percent contingency allowance to account for unforeseen events and unknown field conditions. Capital improvement costs include the estimated construction costs plus 30 percent project-related costs (engineering design, project administration, construction management and inspection, and legal costs). x Existing MDDWF = 2.8 mgd x Existing MDWWF = 3.7 mgd x Buildout MDDWF = 4.7 mgd x Buildout MDWWF = 6.0 mgd

August 2017

ES-11

City of Morgan Hill Sewer System Master Plan