PROJ01996

• Contract/PO #: FS0068FX
• Contractor Name: Minturn, Town of
• Contract Type: Loan
• Water District: 0
• Loan Projects - Doc Type: Feasibility Study

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Concrete tanks also have the advantage of being able to be fully or partially buried. This has
obvious aesthetic benefit, and acts as an insulator against cold temperatures, reducing the
likelihood of ice developing within the tank. Buried tanks require less exterior maintenance,
since no exterior painting is required, and provide a minimal target for vandalism, Concrete
tanks are durable, if constructed correctly, and can provide many decades of low maintenance
service.

The primary disadvantage of constructing the new storage tank with either pre-stressed or
reinforced concrete is the higher initial cost, as shown in Table 9, For the size of tank being
considered,. reinforced concrete appears to be a less expensive alternative than a pre-stressed
concrete tank, by $34,000 (7%), but is still considerably more expensive than an equivalently
sized steel tank. In fact, Table 8 indicates that a reinforced concrete tank is estimated to be
$106,000, or nearly 30%, higher in construction cost than an insulated, above ground steel tank.
In light of the financial resources available to the Town of Minturn for this water system
improvement project, this price differential is critical. In order to fit a concrete tank into the
project budget, a significant downsizing of the tank, from 600,000 gallons to less than 500,000
gallons would be required.

Another disadvantage to concrete construction is that concrete tanks are slightly more prone to
leakage. Slight cracking of the concrete can allow water to infiltrate the walls or base, and may
lead to corrosion of the steel reinforcement. It may be difficult to determine whether leakage
is occurring and to what extent with a buried tank, since visual confirmation of tank condition
is not easily performed due to the earth cover.

The primary advantage of an above ground, insulated steel tank is its lower initial cost. As
mentioned, that is a highly significant advantage for the Town of Minturn. The obvious
disadvantages are: visual impact, higher level of maintenance, possibility of freeze damage, and
susceptibility to vandalism. The visual impact can be mitigated by the use of a high integrity,
attractive insulation system, such as Thermacon's vertical sidewall system utilizing isocyanurate
foam laminated to painted aluminum sheathing. The paint color can be an earthtone, selected
to blend into the hillside environment. Although maintenance can be expected to be higher with
a steel tank, factory-coated bolted steel tanks can come with an interior coating warranty of up
to 15 years. One manufacturer has stated that a maintenance free life of 25 years or more is
common with its thermally set epoxy based interior coatings.

An exposed tank can be a target for vandals, but the town has experienced practically no
vandalism with its existing steel tank. Security fencing could be added at a later date if this
were to become a problem.

Town of Minturn Water System Upgrade Project, March, 1995

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