Tamarack Negotiation with Boulder/Centennial

• File Number: 8461.400
• Description: SPWRAP
• State: CO
• Basin: South Platte
• Water Division: 1
• Date: 9/18/2008
• Author: Steve Sims
• Title: Tamarack Negotiation with Boulder/Centennial
• Water Supply Pro - Doc Type: Court Documents

2.0 APT TESTING ANALYSIS SUMMARY
Two APTs were conducted on the lower South Platte River to determine streambed and aquifer parameters. The
Stieb APT was located approximately 8 miles upstream ofthe TRSWA and the Dinsdale APT was located
immediately downstream of the TRSWA. Analysis of these tests was performed by the following entities:
• Colorado State University, (CSU, 2005 and 2006)
• Hydrosphere Resource Consultants for the City of Boulder (Hydrosphere, 2006)
• Water & Environmental Systems Technology, Inc. for the City of Centennial (W&EST, 2006)
• CDOW (CDOW, 2005)
Table 1 summarizes the aquifer and streambed parameters derived by these parties for both the Stieb and
Dinsdale tests.
Table 1
Lower South Platte River APT
Analyses Summary

Analyses ,
Kh
Kh1Kv2 Specifc
Yield Specifc
Stora e
9 Streambed
Leakanoe
Ksb /M
feeVday nones feeUfeet feet-1 day'?6?
Stieb Test
CSU Groundwater Model' 400 10 0.15 5.0E-05 775
CDOW Analyticat Method 275-320 10 0.2 2.0E-04 n/a
Hydrosphere Theis Method 255 0.15 1.74-2.33
Hydrosphere Hunt Method 441 0.018-
0.017 1.66-4.16
Hydrosphere ET Model 40Q 4 02 10-20
Hydrosphere Recommended 400 4 0.2 20
W&EST Analysis 300 0.1 1.69
Dinsdale Test
CSU Groundwater Modele 310 7.75 0.125 5.OE-05 160-400
CDOW Analytical Model 230-285 10-12.5 0.2 1.0E-04 n/a
Hydrosphere Theis Method 150 0.05 n/a
Hydrosphere Hunt Methodg 198-216 0.015-
0.013 0.024-2.6
Hydrosphere MODFLOW model
(McCord June 2005) 450 02 1.0E-04 1.5
Hydrosphere Recommended 200 4 0.05 2.6
W&EST Analysis 100-260 0.125 0.011
Table Notes:
1. Kh is defined as the horizontal hydraulic conductivity of the aquifer
2. Kv is defined as the vertical hydraulic canductivity of the aquifer
3. Ksb is defined as the hydraulic conductivity of the streambed
4. M is defined as the streambed thickness
5. Units for Kh/Kv are ft/day divided by ft/day which equates to a dimensionless parameter
6. Units for streambed leakance are ft/day divided by ft which simplifies to units of 1/day or day"'
7. A high conductivity zone was established very close to the river (K = 600 feeUday)
8. A high conductivity zone was established very close to the river (Kv = 80 feeUday)
9. Streambed leakance ranged widely depending on time of calibration Ksb/M ranged from 2.6 to 0.024
days' depending on calibration point.
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