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City of Morgan Hill
Sanitary Sewer Flow Monitoring and Inflow/Infiltration Study
12-0248 AEG CofMorganHill FM Rpt.docx
Page 1 of 46
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 1summarizes 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
Metering
Site
ADWF
(mgd)
Peak
Measured
Flow
(mgd)
Peaking
Factor
Diameter
(in)
Peak
Level
(in)
Peak
d
/
D
Ratio
Level
Surcharged
above
Crown (ft)
Site 1
0.19
0.56
2.93
18
3.73
0.21
-
Site 2
0.36
0.88
2.45
19.75
7.94
0.40
-
Site 3
0.32
0.93
2.95
15
13.13
0.88
-
Site 4
0.21
0.53
2.49
12
6.04
0.50
-
Site 5
1.15
2.29
1.98
24
15.95
0.66
-
Site 6
0.35
0.91
2.60
17.75
12.52
0.71
-
Site 7
0.24
0.77
3.17
21
6.82
0.32
-
Site 8
0.16
0.43
2.73
17.5
6.76
0.39
-
Site 9
0.13
0.41
3.03
15
6.36
0.42
-
Site 10
0.12
0.31
2.45
11.75
4.57
0.39
-