City of Morgan Hill Sewer System Master Plan 2017

Other structural defects (PACP Rating 1-3), were used in the process of evaluating how critical the individual pipe segments were. The major structural defects were documented on Figure 7.6 . The individual defects included broken or deformed pipes, holes in the pipe, collapsed pipes, or obstructions located within the pipe. These defects are indicators that pipelines have already failed or are in imminent danger of failing. Infiltration and inflow defects were also documented as part of this analysis and included on Figure 7.7 and Figure 7.8 . These defects can lead to sanitary sewer overflows, premature pipeline upsizing and higher treatment costs. 7.5.3 Improvement Recommendations Improvements recommendations were developed based on the findings of the condition assessment. As pipelines fail to varying degrees and in various locations, the improvement recommendations were grouped by the following criteria: x Risk. This category is based on the failure type and location to critical places, such as schools or creeks. x Location. To avoid costly mobilization and adverse public interference, improvements were grouped into confined neighborhoods. x Cost. Pipelines were also grouped by cost. As it may be cost prohibitive to complete a City-wide rehabilitation and replacement program, improvements were grouped to maintain an annual reasonable cost for budgeting purposes. The project groupings are documented in Appendix C . Once groups were created, they were prioritized by the overall risk of the group, and proximity to other groups. Additionally, City staff identified priority sections of pipeline intended to be replaced in the near- term due to deteriorated conditions or operational considerations ( Table 7.2 ). It should be noted that, for planning purposes, the operational improvements generally involve replacing pipes in kind. These improvements are described as follows: x RP-P1 : Replace the existing 6-inch gravity sewer located on right-of-way along Holiday Drive to Oak Lane. This improvement is meant to mitigate the existing sag in the gravity main that could cause flows to spill into the adjacent lake. It should be noted that this pipeline is planned for rehabilitation and is shown on the condition assessment exhibits included in Appendix C . x RP-P2 : Replace the existing 6-inch gravity sewer along Wright Avenue from 230 feet east of Garden Avenue to Del Monte Avenue. This improvement is meant to repair the existing gravity main that is currently broken.

August 2017

7-11

City of Morgan Hill Sewer System Master Plan