102 / 201
June 2017
7-1
City of Morgan Hill
Water System Master Plan
2017
City of Morgan Hill
7.0
CHAPTER 7 - EVALUATION AND PROPOSED IMPROVEMENTS
This section presents a summary of the domestic water system evaluation and identifies
improvements needed to mitigate existing deficiencies, as well as improvements needed to
expand the system and service growth.
7.1 OVERVIEW
The calibrated hydraulic model was used for evaluating the distribution system for capacity
deficiencies during peak hour demand and during maximum day demands in conjunction with fire
flows. Since the hydraulic model was calibrated for extended period simulations, the analysis
duration was established at 24 hours for analysis.
The criteria used for evaluating the capacity adequacy of the domestic water distribution system
facilities (transmission mains, storage reservoirs, and booster stations) was discussed and
summarized in the System Performance and Design Criteria chapter.
7.2 FIRE FLOW ANALYSIS
The fire flow analysis consisted of using the maximum day demand in the hydraulic model and
applying hypothetical fire flows. The magnitude and duration of each fire flow was based on the
governing land use type within proximity to the fire location. The criterion for fire flows was also
summarized in the System Performance and Design Criteria chapter.
The hydraulic model indicates that the City’s existing distribution system performed adequately
during the fire flow analysis. Areas where the City water system did not meet the fire flow criteria
are documented on
Figure 7.1
. The available fire flow at the City’s residual pressure criteria of 20
psi is summarized on
Figure 7.2
. It should be noted that a majority of the service connections in
the eastern foothills are unable to meet the pressure requirements under fire flow conditions. A
majority of the distribution system serving this area is comprised of 6-inch and 8-inch water
pipelines with minimal looping. It is recommended that as pipeline replacements occur, 6-inch
pipelines be upsized to 8-inch pipelines to reduce the headloss and velocity impacts to this area.
Additionally, where the cost is not prohibitive, it is recommended that looped connections be
constructed for reliability.
Improvements to mitigate specific fire flow deficiencies are discussed below and include a
corresponding coded identifier, which is consistent with the capital improvements chapter:
NH-P2.
Replace approximately 950 feet of 4-inch water main from Del Monte Avenue to
Monterey Road along Spring Avenue with 8-inch water main.
BR-P5:
Replace an 8-inch pip with a new 10-inch pipeline in Mission View Drive between
Cochrane Road and 2,100 feet northwest of Cochrane Road.