City of Morgan Hill Sewer System Master Plan 2017

City of Morgan Hill Sanitary Sewer Flow Monitoring and Inflow/Infiltration Study

EXECUTIVE SUMMARY Scope and Purpose

V&A was retained by Akel Engineering Group to perform sanitary sewer flow monitoring and inflow and infiltration (I/I) analysis within the City of Morgan Hill, California (City). Flow monitoring was performed over a 20-day period at ten open-channel flow monitoring sites within the City. The flow monitoring period began on February 25, 2014, and ended on March 17, 2014. The purpose of this study was to measure sanitary sewer flows at the flow monitoring sites and estimate available sewer capacity and infiltration and inflow (I/I) occurring in the basins upstream from the flow monitoring sites. V&A had access to flow monitoring data from the Harding Avenue Flow Meter. This meter measures the total flow from the City of Morgan Hill through a single 21-inch transmission sewer line sewer prior to entering into the City of Gilroy collection system. Flows from this meter during the flow monitoring period are also presented in this report and used to establish system totals. Site Flow Monitoring and Capacity Results Peak measured flows and the corresponding flow levels (depths) are important to understand the capacity limitations of a collection system. Table 1 summarizes the peak recorded flows, levels, d / D ratios, and peaking factors per site during the flow monitoring period. Capacity analysis data is presented on a site-by-site basis and represents the hydraulic conditions only at the site locations; hydraulic conditions in other areas of the collection system will differ.

Table 1. Capacity Analysis Summary

Peak Measured Flow (mgd)

Level Surcharged above Crown (ft)

Peak Level (in)

Peak d / D Ratio

Metering Site

ADWF (mgd)

Peaking Factor

Diameter (in)

Site 1 Site 2 Site 3 Site 4 Site 5 Site 6 Site 7 Site 8 Site 9

0.19 0.36 0.32 0.21 1.15 0.35 0.24 0.16 0.13 0.12

0.56 0.88 0.93 0.53 2.29 0.91 0.77 0.43 0.41 0.31

2.93 2.45 2.95 2.49 1.98 2.60 3.17 2.73 3.03 2.45

18

3.73 7.94

0.21 0.40 0.88 0.50 0.66 0.71 0.32 0.39 0.42 0.39

- - - - - - - - - -

19.75

15 12 24

13.13

6.04

15.95 12.52

17.75

21

6.82 6.76 6.36 4.57

17.5

15

Site 10

11.75

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