WSP03001

• File Number: 8449.850
• Description: Metro Water Supply Investigation - MWSI
• State: CO
• Basin: South Platte
• Date: 8/1/1995
• Author: Hydrosphere, HRS
• Title: Phase II Conjunctive Use Summary Report - Draft
• Water Supply Pro - Doc Type: Publication

MWSI Project
Phase II Conjunctive Use Summary Report - DRAFT

August 22, 1995

expected to be incurred in any given project year. The present value cost in the last column of
the analysis spreadsheet is the single payment worth factor (I/( I +i)n) applied to costs for each
year and summed to present value where i is the discount rate of five percent and n is the year
since the project began,

The average year one capital cost per acre foot and the net present value operation and
maintenance cost per 1000 gallons for project years two to twenty were calculated for the
northern and southern well fields, The weighted arithmetic average of year one capital costs
($1 AF) is also presented for each wellfield. The year one capital costs for the northern and
southern well fields are shown on the following table,

Year One Capital Costs for Northern and Southern Wellfields

Aquifer
Denver
Upper Arapahoe
Lower Arapahoe
Arapahoe
Laramie-Fox Hills
Weighted Average

Northern Wellfield ($IAF)
$1,914
$2,949
$2,566
n/a
$2,487
$2,469

Southern Wellfield ($IAF)
$1,553
n/a
n/a
$1,553
$2,211
$1,671

The results of the northern and southern well field analyses show that it is less expensive
to develop Denver Basin aquifer groundwater in the southern portion of the basin. The reason
for the less expensive cost in the southern part of the basin is that wells in the southern portion of
the basin are capable of producing more water than wells in the north, Therefore, fewer wells are
required in the south, In addition to well drilling and equipping costs, fewer wells result in lower
pipeline and power line costs.

The analysis which evaluated Denver Basin groundwater production between northern
and southern well fields in the metro area concluded that groundwater production is more cost
effective in the southern metro area, A second cost analysis was perfonned to detennin'e if it was
more cost effective to pump Denver Basin aquifer groundwater from (I) Denver, Arapahoe and
Laramie-Fox Hills aquifers; (2) the Denver and Arapahoe aquifers; or (3) only the Arapahoe
aquifer. To evaluate these alternatives, costs for a 30,000 affyr well field in the southern metro
area were prepared for each alternative. The following table shows the volume of water and
number of wells related to each alternative.

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