City of Morgan Hill Sewer System Master Plan 2017

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

Flow Monitoring: Average Dry Weather Flows Weekday and weekend diurnal flow patterns differ and can be separated when establishing average dry weather flow rates. Within weekdays, the average dry weather flow (ADWF) patterns for Friday will vary from the Monday through Thursday patterns, particularly in the evening hours as people prepare for the weekend. Similarly, Sunday flow patterns typically vary in the evenings from Saturday flow patterns as people prepare for the work week. Figure 15 illustrates the varying flow patterns within a work week (Site 7 shown). Graphs of the ADWF flow patterns for each site may be found in Appendix A . 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 00 Flow (mgd) Hour Mon-Thu Friday Saturday Sunday Site 7: Average Daily Flows

Figure 15. Sample ADWF Diurnal Flow Patterns (Site 7)

The overall average dry weather flow (ADWF) is calculated per the following equation:

7 4

7 1

7 1

7 1

  

 

  

 

  

 

  

  

,

ADWF

ADWF

ADWF

ADWF

ADWF

+

×

+

×

+

×

=

×

− Thu Mon

Fri

Sat

Sun

Table 8 lists the average dry weather flow (ADWF) recorded during this study for the flow monitoring sites. Figure 16 shows a schematic diagram of the average dry weather flows and flow levels.

12-0248 AEG CofMorganHill FM Rpt.docx

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