BOARD00234

• Board Meeting Date: 7/23/2002
• Description: CWCB Director's Report
• Board Meetings - Doc Type: Memo

is currently in progress, with ground-water modeling work, continuing for fue Denver Basiu Aquifer.
Hydrosphere Resource Consultants is performing modeling work on a regional basis, while HRS Water .
Consultants is employing regional model head results in in\lividual well analyses throughout the study
area. A draft report is tentatively scheduled to be completed in September 2002.

29. Arkansas Well Measurement Proltfam
Aufuorization: SB 97-008 Grant Amount: $100,000 Phase I
HE 98-1189 $ 75,000 Phase! Cont.
SB 01-157 $ 50.000 Phase II
Total $225,000
Water Source: Alluvial Groundwater Project Type: Cooperative Study to
Location: Pueblo, Otero, Bent, Prowers, Crowley Counties support interstate litigation
Managers: Randy Seaholm f Steve Miller

This two-phase study was to analyze the validity of the State Engineer's well pumping measurement
rules for fue Arkansas Basin. Those rules allowed pumping volumes to be determined by reference to
energy consumption of the pumping equipment, and calculation of acre-feet pumped using a Power
Conversion Coefficient [pCC]. The PCC is determined in!fue field separately for each well by a pump
test. This study, conducted by the US Geological Survey, involved supervising data collection during
retests of well PCC's at randomly selected wells where a, totalizing flow meter was also installed and
comparing fue pumping estimates obtained by the two methods. Statistical analysis was then conducted
to demonstrate fuat the PCC mefuod was as accurate as the totalizing meter method. In Phase 1, which
was completed several years ago, the initial meter installation, data collection for two years, and analysis
resulted in a final, published USGS report. This report WS$ fuen presented to the State of Kansas and the
Special Master to support the reliability of Colorado's compact compliance efforts. The information will
also have applications in other basins where the PCC method may be used to determine groundwater- .
pumping volumes. .

At the conclusion of Phase 1 it was determined fuat it would be useful to collect several more years of
data to evaluate changes in fue PCC for fue study wells over time and prepare a concluding report. The
analysis to be conducted during PhaSe 2 will hopefully strengthen Colorado's position that the PCC
method is statistically equivalent to the use of totalizing flow meters and also provide the SEa with
information to support requirements for well PCC re-tests. SBOl-157 funded fuis Phase 2 effort in the
amount of $50,000. Those funds will be transferred to tJie SEa via an MOU, and he will then contract
with the USGS for additional data collection, analysis, and the concluding report. Data collection is
continuing and is somewhat dependent on manpower and water availability. It is estimated that the
concluding report will be completed in late 2003.

30.

Purgatoire River Transit Loss Investigation Studv
Aufuorization: HE 95-1155, SB 99-173
Water Source: Purgatoire River
Location: Las Animas County

Grant Amount: $60,000
Proj ect Type: Cooperative Study
Managers: Randy Seaholm f Steve Miller

The study cost for Phase I of this project is $101;800, with CWCB's share at $20,650. The study
cost of Phase 2 is estimated at $150,000.

This project is being conducted by the Purgatoire River Water Conservancy District [PRWCD] in
conjunction with the USGS and USBR. In Phase 1 it was determined fuat on an annual average basis
mainstem losses were offset by gains. In Phase 2 the remaining $39,000 of CWCB funding will pay for a
portion of the cost of an analysis of transit losses iu the ()onveyance systems of the participating members .
of fue PRWCD. This information will enable the PRWCD to better allocate its water supply, and will

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