FLOOD10427

• County: Arapahoe
• Title: South Metro Water Supply Study - Technical Appendices
• Date: 2/1/2004
• Prepared For: South Metro Water Supply Study Board
• Prepared By: Black & Veatch, Rick Giardina & Associates, HRS Water Consultants, Hydrosphere
• Floodplain - Doc Type: Floodplain Report/Masterplan

Figure E-l- EcCVWSD Monthly Water Demands

ECCVWSD Monthly Water Demand (1991-2000)

500.0
450.0
400.0
350.0.
.J: 300.0.
;:
0
E
a
:~ 250.0 .
OJ
"
'ii
E 200.0.
::l
l1.
150.0
100.0
50.0.
0.0
Jan. Feb. Mar. Apr.

10 Series 1
III Series2
10 Series3
o Series4
. Series5
o Series6
II Series 7
o Series8
. Series9 I
IL'lISeries10 i

May

June July
Month

Aug.

Sept

Oct.

Nov.

Dec.

Water Usage

For planning purposes, ECCVWSD assumes a water demand of 0.6 ac.ft.lSFE. For sizing well
and pump station capacity, the District assumes a maximum day demand of2.21 times average
flow (1,103 gpd/ SFE). Peak hourly flows are assumed to be 6.0 times average flows.

The ultimate build-out water use planning horizon represents the water demands for 23,050
residential units (based on a %" tap equivalent). The District plans on issuing 1 000 tap
equivalents per year (600 acre-feet per year) in new service obligations through 2010 when it is
assumed that the District will be at full build-out.

Denver Basin Aquifer Properties

ECCVWSD relies primarily on the Araphoe and Laramie-Fox Hills formations for its water
supplies. In this part of the Denver Basin, the Dawson is not used because of issues and its use by
small domestic wells and the Denver formation is non-productive as a municipal water source. In
this area of the aquifer, the Arapahoe formation produces about 0.5 acre-feet per acre and the
Laramie-Fox Hills formation produces about 0.3 8 acre-feet per acre for a total production of 0.88
acre-feet per acre. Arapahoe wells will produce from 100 - 300 acre-feet per year per well at a
fate typically of250 - 350 gallons per minute. Transmissivities in the Arapahoe formation