PROJ00237

• Contract/PO #: C153400
• Contractor Name: Larkspur, Town of
• Contract Type: Loan
• Water District: 8
• County: Douglas
• Bill Number: SB 79-537
• Loan Projects - Doc Type: Feasibility Study

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Storage

The location and volume of storage required for the proposed service

area is shown on Map 1. The location has been selected to achieve a high water

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elevation of 6970 feet, the elevation required to generate sufficient static

pressure on the water distribution lines proposed for the area along Fox Farm

Road south of Larkspur.

This highwater level will create static pressures of 139 psi (pounds per

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square inch) in the lower areas of Larkspur and pressure reducing stations

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will be required to lower the operating pressure to about 80 psi maximum.

Storage volume required is calculated by three different formulas to

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accomplish specific objectives, Those objectives and the corresponding formulas

are:

1. Create a reserve to equalize pumping rates over a day.

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Formula: Volume = 157. to 307. of maximum day demand.

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2. Reduce the amount of water supply required by using
storage to satisfy the excess demand during the few
hours of "peak hour" demand occuring on maximum
demand days.

Formula: Volume = ((Peak Hour - Max Day) x 4 Hrs)

3. Provide required fire flows for the fire duration.

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Formula: Volume = (Fire Flow + Max Day - Supply)x Duration

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Using these formulas and the assumed demand rates described in Section II,

the required volumes for the design population are presented below. The minimum

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required fire flow is assumed to be 500 gpm with a minimum duration of 2 hours.

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Formula 1:
Volume = 157. to 307. (225 PE x 300 gpcd)
= 10,000 to 20,000 gallons
Use Vol= 20,000 gallons

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