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To: Jay Pansing and Roy Enter
From: Amanda Peirce and Chris Sanchez
Subject: Projections of Water Requirements for Two Development Scenarios and Water Supply
Availability in Accordance with Weld County 300-Year Rule
Job: 0533.00
Date: March 14,2006
As requested by Mr.Jay Pansing, we have updated our ground water availability estimates based
on Weld County's 300-year rule, and completed an estimate of the water requirements for two
development scenarios in order to determine water supply adequacy based on the 300-year rule.
Our ground water quantification based on a 100-year aquifer life was presented in a previous
memo dated December 20, 2005, although it should be noted that the values presented below are
based on an updated property area of 138 acres. The updated ground water quantification based
on a 300-year aquifer life is presented in Table 1.
Table 1
ANNUAL APPROPRIATION FOR A 138 ACRE TRACT PER WELD COUNTY 300-YEAR RULE:
SEC. TWP RNG ACRES
28 02N 64 138
NONTRIBUTARY NOT NONTRIBUTARY
TOTAL
AVERAGE ANNUAL AVERAGE ANNUAL ANNUAL
AQUIFER ACRES SAT. APPROP ACRES SAT. APPROP APPROP
UPPER DAWSON
LOWER DAWSON
DENVER
UPPER ARAPAHOE
LOWER ARAPAHOE 138.0 85.2 6.7 6.7
LARAMIE-FOX HILLS 138.0 158.4 10.9 10.9
Note: These quantities are based on a 300-year aquifer life per Weld County Amend Section 27-2-170, Public
Water Provisions). The actual economic life of the aquifer may be less than 300 years. Actual ground water
availability will not be known until wells are drilled,constructed,and tested on the property.
As stated above, two development scenarios were considered. Scenario 1 represents the water
requirements for 9 single-family residential lots and 4 industrial lots. Scenario 2 represents the
water requirements for 13 single-family residential lots and no industrial lots. As presented
below, the projected water requirements for each scenario does not exceed the available
nontributary ground water entitlement of 10.9 acre-feet per year(Table 1).
2007-2012
Page 2
March 14,2006
For both scenarios water use rates for industrial uses and outside irrigation were taken from the
Douglas County Zoning Resolution Section 18A, Water Supply—Overly District which assumes
0.1 gallons per square foot per day for industrial uses and 2.5 acre-feet/acre for irrigation uses.
In-house residential demands were based on 3.5 people per household and 80 gallons per day per
person.
Scenario 1 which is outlined in Table 2 includes nine residential lots with 6,000 square feet per
lot of irrigation and 4 industrial use lots with 1,000 square feet of irrigation per lot. Scenario 2
includes 13 residential lots and no industrial lots. For Scenario 2, the available ground water
supplies can support up to 9,000 square feet of irrigation per lot.
Because of the uncertain water uses accnciated with the industrial lots, and because the
development will rely on non-renewable water supplies, we recommend including provisions to
minimize outdoor irrigation. Although the annual nontributary entitlement is sufficient to
support large irrigated areas, we recommend a development plan with smaller lawn sizes. Note
that only 98 percent of the nontributary water is consumable in accordance with Senate Bill 5,
but as presented in Table 2, more than 40 percent of the water pumped from the nontributary
Laramie-Fox Hills aquifer will be return flow, which is more than adequate to provide sufficient
relinquishment to the stream system.
Table 2•
Determiaatioa of Water Demist and Conampdve Use
Eater Property
9 Resideatiel Lots mad 4 industrial Use Loh
lathier Residential Irrigates.
9 Single-Family Residential Lots 6,000 feta
33 parsons per unit 54,000l
80 gal/person/day 1.24 ac
2.00 ofac
•
4 Industrial USE Lob 80% %effamcy
10,000 Square-feet of building spacaLot 3.10 ac-ft
0.1 pVagf/day
ladastrial Irrigates.
1,000 ft"Lot
4,000 fl
0.09 ac
2.00 oft/ec
80% %efciency
0.23 oft
Indoor Outside Irrigation Total
Residential Industrial Residential Industrial
Month Demand Demand CU Demand Demand CU Demand CU
(at) (a° (at) [af (an (at) (at) (at)
[1] (2] [3] [4] [51 [6] [7] [81
Jan 0.24 0.38 0.06 0.62 0.06
Feb 0.22 0.34 0.06 0.56 0.06
Mar 0.24 0.38 0.06 0.62 0.06
Apr 0.23 0.37 0.06 0.60 0.06
May 0.24 0.38 0.06 0.23 0.02 0.20 0.87 0.26
Jim 0.23 0.37 0.06 1.05 0.08 0.90 1.73 0.96
Jul 0.24 0.38 0.06 0.98 0.07 0.84 1.67 0.90
Aug 0.24 0.38 0.06 0.55 0.04 0.47 1.21 0.54
Sep 0.23 0.37 0.06 0.29 0.02 0.25 0.92 0.31
Oct 0.24 0.38 0.06 0.62 0.06
Nov 0.23 0.37 0.06 0.60 0.06
Dec 0.24 0.38 0.06 0.62 0.06
Total 2.82 4.48 0.28 3.10 0.23 2.66 10.63 3.39
Notes:
(1)Residential demands based on 100%occupancy,9 units,3.5 persons per unit,80 gallons per poison per day.
(2)Industrial demands based on 100%occupancy,4 lots,6000 sqfl of building space per lot,0.1 gallons per sqft per day.
(3)Total Indoor Consumptive Use based on 10%CU,((1)+(2))•0.1
(4) Residential Irrigation demand,2.5 acre-feet/aae,distributed ova May-September
(5) Industrial Irrigation demand,2.5 acre-feet/acre,distributed over May-September
(6) Total Irrigation Consumptive Use,based on 80%CU
(7) Total demand,equal to[I]+[2]+[4]+[5]
(6) Total CU,equal to[3]+[6]
•Water use rates from the Douglas County Zoning Resolution Section 18A,Water Supply-Overlay District
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Table 3
Determination of Water Demands and Comnmpdve Use
Eater Property
13 Residential Lots and No ladastrial Use Lots
Indoor Rddeadal iniptka
13 Single-Family Residential Lets 9000 ftvym
3.5 Pens per unit 117,000 ft
80 gal/persoo/day 2.69 ac
2.00 aro-fl/ac
0 Industrial Use Lids 80% %efficiency
6,000 Square-feet of building apace/Lot 6.71 oft
0.1 gal/egft/dsy
ladastrial Iniptka
0 ft1Lat
0 02
0.00 ac
2 sea/ac
80% %effcimry
0.00 oft
Indoor Outside Irrigation Total
Residential Industrial Residential Industrial
Month Demand Demand CU Demand • Demand CU Demand CU
(af) Off) (at) (at) Off) (at) (at) (al)
[I] [2] [3] [4] [5] [6] [7] [8]
Jan 0.35 0.00 0.03 0.35 0.03
Feb 0.31 0.00 0.03 0.31 0.03
/"'-• Max 0.35 0.00 0.03 0.35 0.03
Apr 0.34 0.00 0.03 0.34 0.03
May 0.35 0.00 0.03 0.50 0.00 0.40 0.84 0.43
km 0.34 0.00 0.03 2.27 0.00 1.82 2.60 1.85
Jul 0.35 0.00 0.03 2.12 0.00 1.69 2.46 1.73
Aug 0.35 0.00 0.03 1.20 0.00 0.96 1.54 0.99
Sep 0.34 0.00 0.03 0.64 0.00 0.51 0.97 0.54
Oct 0.35 0.00 0.03 0.35 0.03
Nov 0.34 0.00 0.03 0.34 0.03
Dec 0.35 0.00 0.03 0.35 0.03
Total 4.08 0.00 0.41 6.71 0.00 5.37 10.79 5.78
Notes:
(I)Residential demands based on 100%occupancy,13 nub,3.5 persons per unit,80 gallons per person per day.
(2)Industrial demands based on 100%occupancy,0 lots,6000 sqft of building space per lot,0.1 gallons per sqft per day.
(3)Total Indoor Consumptive Use based on 10%CU,((1)+(2))•0.1
(4) Residential Irrigation demand,2.5 acre-feet/scre,distributed over May-September
(5) Industrial Irrigation demand,2.5 axe-feet/acre,distributed over May-September
(6) Total Irrigation Consumptive Use,based on 80%CU
(7) Total demand,equal to[l1+121+[41+[5]
(6) Total CU,equal to[3]+[6]
•Water use rates from the Douglas County Zoning Resolution Section 18A,Water Supply-Overlay District
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