PROJECT INFORMATION:
The Cheyenne Board of Public Utilities (CBPU) serves 61,890 people and
17,571 taps. In 1992, the CBPU requested funding for several projects.
The WWDC suggested the CBPU complete a master plan to prioritize future
improvements. The city's existing master plan had become dated and did
not address the latest EPA requirements.
In 1993, the Wyoming Legislature approved funding to update the Cheyenne
Water Supply Master Plan. In 1994 the master plan was completed and
provides an inventory of the existing supply, treatment, and
distribution systems. The plan identified needed improvements,
suggested priorities, estimated costs, and serves as a planning tool
for the city. Approximately $62,000,000 in needed capital improvements
were identified. The identified improvements include an extensive
upgrade to the CBPU Sherard Water Treatment Plant and several
transmission system improvements. These improvements were prioritized
and recommended for completion by the year 2007. Additional Level II
analysis was recommended to refine designs and cost estimates.
In 1996, States West Water Resources Corporation completed a Level II
study of the Cheyenne Water Supply System. Conceptual designs and cost
estimates were prepared for 1) a raw water system to irrigate parks and
golf courses, 2) piping and improvements to the raw water lines feeding
the water treatment plant, 3) a new water transmission main to the east
side of Cheyenne, 4) corrosion analysis, and 5) improvements to the
Supervisory Control and Data Acquisition System. The Level II report
recommended that the first priority of the CBPU should be construction
of a raw water irrigation system. Under this concept an existing 16-inch
main would be converted from treated water to raw water to irrigate
303 acres of land.
Many of the sprinkler systems in the Northwest quadrant parks are not
presently metered and are relatively antiquated. Present water usage on
the Northwest park complexes is uncertain, but lies somewhere between
2.4 mgd and 5 mgd for peak day demands. Due to the paucity of
irrigation flow records, the Level II study utilized the maximum net
irrigation provided by the Wyoming Irrigation Guide. The amounts of
flow projected in the Level II study are therefore lower than actual.
The objective of the project is to convert as many parks and golf
courses to raw water as is reasonably possible. With average daily flow
in the order of 8 mgd and summer peaks in the 40 mgd range, it is
obvious that measures to cut irrigation demands are warranted. Each 1
mgd in reduced treatment capacity saves $1.1 to $1.3 million in capital
cost, plus reduced O&M costs. Direct capital cost savings would be in
the range of $2.64 to $6.5 million for water treatment plant
construction.
The Level II study shows that the alternative 30 year present worth of
utilizing the existing 16-inch line for raw water delivery versus
furnishing treated water for irrigation purposes saves between $5.216
and $6.329 million depending upon which financing alternative is
available.
RECOMMENDED LEGISLATIVE ACTION:
The WWDC recommends the project be advanced to Level III with an
appropriation of $1,800,000 (50% grant, 50% loan at 7.25% for 10 years)
to complete a raw water irrigation system for parks and golf courses in
the northwest part of town.