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City of Morgan Hill
Sanitary Sewer Flow Monitoring and Inflow/Infiltration Study
12-0248 AEG CofMorganHill FM Rpt.docx
Page 20 of 46
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.
Figure 14. Storm Event Classification (RG East)
Table 7summarizes the classification of the rainfall events that occurred during the flow monitoring
period.
Table 7. Classification of Rainfall Events
Rain
Gauge
Event 1:
February 28-March 1, 2013
Duration:
3 Hour
Duration:
6 Hours
Duration:
12 Hours
RG West
<1 Year
1 Year
<1 Year
RG East
5 Year
4 Year
2 Year
RG South
2 Year
2 Year
1.5 Year
1
2
5
10
25
50
100
0
1
2
3
4
5
6
7
Inches of Rain
February 26 - March 2, 2014
1-hr
2-hr
3-hr
6-hr
12-hr
24-hr