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August 2017
5-4
City of Morgan Hill
Sewer System Master Plan
x
Maximum Month Wet Weather Flow (MMWWF).
This maximum month flow occurs
during the wet weather season.
x
Maximum Day Dry Weather Flow (MDDWF).
This is the highest measured daily flow that
occurs during a dry weather season.
x
Maximum Day Wet Weather Flow (MDWWF).
This is the highest measured daily flow
that occurs during a wet weather season.
x
Peak Dry Weather Flow (PDWF).
This is the highest measured hourly flow that occurs
during a dry weather season.
x
Peak Wet Weather Flow (PWWF).
This is the highest measured hourly flow that occurs
during a wet weather season.
Table 5.1
shows the average annual flows (AAF) contributed by the City at the SCRWA WWTP
have decreased from 2.85 mgd in 2010 to 2.37 mgd in 2015, which is a decrease of
approximately 17%. In general, the AAF flows have decreased slowly from 2010 to 2015, and
decreased by 12 % between 2014 and 2015.
Table 5.1
also indicates tha
t the City’s AAF
is
generally close to the Maximum Month Dry Weather Flows (MMDWF).
In addition to listing the 2010-2015 flows, and for comparison purposes, the table calculates the
peaking factors applied to the corresponding average dry weather flows (ADWF) for each year.
During wet weather flows in 2015, the maximum daily volume (MDWWF) contributed by the City
at the SCRWA WWTP was 1.64 times higher than the average dry weather flow for the same
year.
5.2 EXISTING SEWER FLOWS BY MONITORING BASIN
The existing sewer flows represented in this Master Plan were based on the C
ity’s
water
consumption billing records. The number of acres and corresponding sewer flows, for sewer flow
metering basin, are summarized on
Table 5.2
. The sewer flow monitoring basins are also shown
in Chapter 3 on
Figure 3.5
x
Basin 1.
This basin includes 9 percent of the total acres and 7 percent of the existing dry
weather flows.
x
Basin 2.
This basin includes 10 percent of the total acres and 9 percent of the existing dry
weather flows.
x
Basin 3.
This basin includes 4 percent of the total acres and 6 percent of the existing dry
weather flows.