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June 2017
5-5
City of Morgan Hill
Water System Master Plan
customers in the City of Gilroy. In 1999, a joint partnership between SCRWA, SCVWD, the City of
Morgan Hill, and the City of Gilroy sought to develop a recycled water system that would enhance
the wastewater treatment plant and the recycled water distribution system. In March 2016, the
Recycled Water Feasibility Evaluation (RWFE) identified potential recycled water users through a
market assessment; the potential future uses of recycled water in the City include landscape
irrigation, agricultural irrigation, industrial processes, and potable reuse. The RWFE also identified
infrastructure required to convey recycled water from the SCRWA WWTP in Gilroy to the City
(
Figure 5.1
). Due to technical and economic infeasibility there are currently no plans to construct
this infrastructure.
5.4 MAXIMUM DAY AND PEAK HOUR DEMANDS
The maximum day and peak hour demands for the existing and future demands were calculated
using the average day demands and City peaking factor criteria. The maximum day to average
day ratio of 2.0, and peak hour to average day ratio of 3.0, were applied to the average day
demands to obtain estimates of the higher demand conditions. The maximum day and peak hour
demand estimates for the buildout of the Urban Growth Boundary are 18.7 mgd and 28.1 mgd,
respectively; the maximum day demand is 1.80 times the average day demand and the peak hour
demand is 2.80 times.
5.5 DIURNAL DEMAND PATTERNS
Water demands vary with the time of day and by account type according to the land use
designation. These fluctuations were accounted for in the modeling effort and evaluation of the
water distribution system. The diurnal demand patterns affect the water levels in storage
reservoirs and amount of flow through distribution mains.
Three different diurnal curves (
Figure 5.2
) were used to model the demand patterns of 1)
residential, 2) commercial, industrial, and other non-residential, and 3) irrigation use accounts. In
the absence of data that can be used to develop these curves, they were based on industry
acceptable demand patterns for these corresponding land use types. The diurnal patterns were
confirmed during the calibration effort of the City’s hydraulic model and corresponding SCADA
information.
Each diurnal curve has a unique pattern that creates maximum and minimum flow conditions at
different times of the day. Residential demands peak in the morning and evening and are at a
minimum during the night hours. Non-residential demands, which include commercial,
institutional, and industrial demands, are also at a minimum during the night; however, they
remain at a constant maximum from the hours of 8 AM to 5 PM. The irrigation demands are
highest at night and lowest during the day.