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June 2017
7-4
City of Morgan Hill
Water System Master Plan
7.3 LOW PRESSURES ANALYSIS
The hydraulic model was also used to determine if the existing domestic water distribution system
meets the City’s System Performance and Design Criteria for maximum day and peak hour
pressures, as discussed in a previous chapter. During maximum day demands the minimum
pressure requirement is 40 psi, while during the peak hour demand, the minimum pressure
requirement is 35 psi. The hydraulic analysis indicated the City’s existing system performed
reasonably well during under maximum day (
Figure 7.3
) and peak hour (
Figure 7.4
) operating
conditions.
7.4 HIGH PRESSURE ANALYSIS
The hydraulic model was also used to identify areas in the City’s existing domestic water
distribution system that experience high pressure under maximum day demand conditions. The
areas of high pressure are shown graphically on
Figure 7.5
. Areas of high pressure may be more
susceptible to pipeline breaks and ruptures. The City’s maximum desired pressure criterion is 100
psi. The areas experiencing high pressures are briefly described as follows:
Woodland Pressure Zone:
Development near Rocky Ridge Road and Rolling Hills Road,
east of the Woodland Reservoir experience maximum pressures between 150 and 225
psi. These developments are served by the Woodland storage reservoir, which has a base
elevation of approximately 1,080 feet and serves developments with elevations as low as
630 feet.
Llagas Pressure Zone:
Development along Llagas Road, east of Enderson Court,
experience maximum pressures between 150 and 200 psi. These developments are
served by the Glen Ayre Reservoir. These developments are served by the Llagas storage
reservoir, which has a base elevation of 700 feet and serves developments with elevations
as low as 360 feet.
Holiday Lake Pressure Zone:
Development along Thomas Grade east of Dunne Avenue
experience maximum pressures between 150 and 225 psi. These developments are
served by the Holiday Lake Reservoirs, which have a base elevation of 960 feet and serve
developments with elevations as low as 500 feet.
7.5 WATER SUPPLY REQUIREMENTS
The City’s existing domestic water system supply capacity is identified in this section. Additionally,
this section identifies the additional supply capacity required to meet the supply requirement, and
consistent with the City’s System Performance and Design Criteria.
7.5.1
Existing Supply Requirements
Existing supply requirements were identified for the City and are summarized on
Table 7.1
. The
City’s existing water supply requirement was based on the existing land use and recommended