City of Morgan Hill Sewer System Master Plan 2017

City of Morgan Hill

Sanitary Sewer Flow Monitoring and Inflow/Infiltration Study

12-0248 AEG CofMorganHill FM Rpt.docx

Page 16 of 46

RESULTS AND ANALYSIS

Rainfall: Rain Gauge Data

V&A utilized rain data from rain gauges maintained by local weather enthusiasts. While V&A

performed QA/QC analysis to ensure, to the extent possible, the quality of the rainfall data from the

three rain gauges used, it is noted that V&A has no direct control over these gauges.

There were five rain events stacked over seven days from February 26 to March 5, 2014. The largest

individual rain event occurred on February 28, 2014 and this event was used for infiltration and inflow

analysis for this study.

Table 5 s

ummarizes the rainfall data collected for this study.

Figure 10

graphically displays the rainfall activity recorded over the flow monitoring period (average of the three

rain gauges shown).

Table 5. Rainfall Events Used for I/I Analysis

Rainfall Event

RG WEST

Event

Rainfall

(in)

RG EAST

Event

Rainfall

(in)

RG SOUTH

Event

Rainfall

(in)

Event 1: February 28 – March 1, 2014

1.74

2.16

2.26

Total over Monitoring Period

3.16

3.34

4.06

Figure 10. Rainfall Activity over Flow Monitoring Period (Avg. of Rain Gauges)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

0.55

25-Feb

26-Feb

27-Feb

28-Feb

1-Mar

2-Mar

3-Mar

4-Mar

5-Mar

6-Mar

7-Mar

8-Mar

9-Mar

10-Mar

11-Mar

12-Mar

13-Mar

14-Mar

15-Mar

16-Mar

Rain (inches per hour)

Total Rainfall over Period: 3.52 inches

1.17 inches

2.05 inches