PROJ00156

• Contract/PO #: C153721
• Contractor Name: Lyons, Town of
• Contract Type: Loan
• Water District: 5
• County: Boulder
• Loan Projects - Doc Type: Feasibility Study

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5. WATER TRANSMISSION, DISTRIBUTION AND STORAGE

5.1 Review of the Existing System

Pressure Zones and System Operations

The Town of Lyons water system presently has two pressure zones, the upper zone and
the lower zone. The upper zone serves the Apple Valley Road area and the higher areas
around the town. The lower zone comprises the majority of the town, and most future
development will occur in the lower zone. The water services in the vicinity of Reese Street
are located in the high pressure zone, but are served by the lower pressure zone distribution
system. This area is in the "fringe" between zones and although domestic flow demand can be
met, any large demand (Le. fire flow) on the system will result in inadequate flow. Refer to
Figure 5 for a map of the pressure zones and the existing annexed town boundaries.
Generally, it is desirable to maintain static pressures in a municipal water distribution system
between 40 pounds per square inch (psi) and 100 psi at ground level. The town's 1.0 MG
water storage tank, located at a high water elevation of about 5704 feet, sets the static pressure
for the upper zone and feeds the upper zone directly by gravity via a I2-inch transmission line.
This delivery system also feeds the Town's lower pressure zone through a pressure reducing
valve (PRV) and a second tank, with a capacity of 0.35 MG, located in the downtown area at
high water elevation of 5516 feet. Supply to this tank is shut off by an altitude valve when the
tank is full. The 0.35 MG tank currently provides a portion of the storage for the lower zone.

The lower zone, comprising most of the town, is fed mainly from the upper zone tank, via the
main transmission line and a pressure regulating valve (PRV) in Fifth Avenue. For most of a
24-hour period, the PRY is set for 68 psi on the lower zone side. To circulate water in the
0.35 MG tank, the PRY is closed in accordance with an operating rule: one 4-hour period each
day or until 100,000 gallons of water is consumed from the tank by the lower zone. Data for
definition of the pressure zones is shown in Table 7.

Water Storage for Domestic Use and Fire Flows

A water storage and distribution system must have sufficient capacity to deliver an
adequate amount of water to meet "worst case" demands. As shown in Table 3 of this report,
the average value of the peak day production at the water treatment plant is 1.03 million gal

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