City of Morgan Hill Sewer System Master Plan 2017

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

From the NOAA frequency maps, for a specific latitude and longitude, the rainfall densities for period durations ranging from 15 minutes to 60 days are known for rain events ranging from 1-year to 100-year intensities. These are plotted to develop a rain event frequency map specific to each rainfall monitoring site. Superimposing the peak measured densities for Event 1 on the rain event frequency plot determines the classification of the storm event, as shown in Figure 14 for RG East.

7

100

February 26 - March 2, 2014

50

6

25

5

5 10

4

3

1 2

Inches of Rain

2

1

0

1-hr

2-hr

3-hr

6-hr

12-hr

24-hr

Figure 14. Storm Event Classification (RG East)

Table 7 summarizes the classification of the rainfall events that occurred during the flow monitoring period. Table 7. Classification of Rainfall Events

Event 1: February 28-March 1, 2013

Rain Gauge

Duration: 3 Hour

Duration: 6 Hours

Duration: 12 Hours <1 Year 2 Year 1.5 Year

RG West RG East RG South

<1 Year 5 Year 2 Year

1 Year 4 Year 2 Year

12-0248 AEG CofMorganHill FM Rpt.docx

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