PROJ00061

• Contract/PO #: C153366
• Contractor Name: Ridges Metropolitan District
• Contract Type: Loan
• Water District: 72
• County: Mesa
• Bill Number: SB 81-439
• Loan Projects - Doc Type: Feasibility Study

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CHAPTER V - PLAN OF DEVELOPMENT

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A. Physical Plan

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The proposed project when completed will include a primary pump station
located at the Redlands Power Canal Tailrace near the Colorado River, two
(2) sixteen-inch pipelines from the primary pump station to two proposed
storage reservoirs and two pump stations (one at each storage reservoir).
The preliminary plans for the primary pump station, the twin sixteen-inch
pipelines and one of the storage reservoirs are included in Appendix C of
this report.

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Most of the sixteen-inch pipeline has been installed. Since it is located
under paved portions of a major artery it was necessary to install the line
before paving and avoid the added cost of installing the line under a fin-
ished roadway.

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The proposed plan is to be implemented in two phases. The first phase will
include the primary pump station, the first storage reservoir and its asso-
ciated pumping facilities, and the remaining portion of the sixteen-inch
transmission line (between the primary pump station and Broadway Avenue).

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The second phase will include the sixteen-inch pipeline remaining from the
first storage reservoir to tqe second reservoir, and the construction of
the second reservoir and its associated pumping facilities.

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B.

Geologic Investigations

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For the first storage reservoir and its dam, a geologic investigation has
been conducted. This report is included in Appendix B of this report. It
is anticipated that the geologic conditions will be similar for the second
storage reservoir. However, a detailed investigation has not yet been com-
pleted for the second reservoir.

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A brief summary of the investigation that the actual amount of silty, clayey
sand borrow was found to be quite thin over the site, with a maximum thick-
ness of seven feet. Underlying the sand is a thin zone of sandstone and
shale beds which are from one-half to six feet thick. The shales are of
moderate to high plasticity and will make excellent core material for the
proposed dam. The sandstones eventually become nonexistant after about six
feet of penetration and a high plastic claystone and shale is present for
another 12 to 35 feet. This sandstone and shale sequence is the Upper Member
of the Burro Canyon Formation.

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A similar investigation was made into the geologic conditions of the primary
pump station. It too is included in AppendixB of this report. A summary
of this report the soil profile encountered in the test borings consisted of

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