SPDSS_Task82_ReviewPublishedReports_WaterBudgets

• Title: SPDSS Task 82 - Review Published Reports on Water Budgets
• Description: This memorandum summarizes the results of Task 82 of the Consumptive Use and Water Budget portion of the South Platte Decision Support System ‎(SPDSS)‎ effort.
• Decision Support - Doc Type: Task Memorandum
• Date: 4/7/2005
• DSS Category: Water Budget
• DSS: South Platte
• Basin: South Platte
• Contract/PO #: C153953
• Grant Type: Non-Reimbursable
• Bill Number: SB01-157, HB02-1152, SB03-110, HB04-1221, SB05-084, HB06-1313, SB07-122
• Prepared By: Leonard Rice Engineering

Surface water outflows were derived consistently in the studies using recorded outflows at the
South Platte River at Julesburg stream gage. However, given different study periods, the average
annual outflows ranged from 300 kaf/yr to 393 kaf/yr.
• Exports
There are no transmountain exports from the South Platte River basin. Transmountain exports
were estimated in the USBR study (1970) for the North Platte River basin (1.3 kaf/yr) and the
Laramie River basin (19.7 kaf/yr) within the state of Colorado.
• Ground Water Ou~ows
Ground water outflows in the studies from the lower South Platte River basin in the state of
Colorado ranged from 8 kaf/yr to 20 kaf/yr. The differences between the estimates are likely due
to variable study approaches and variable study periods.
Changes in Storage
• None of the studies estimated changes in surface water storage.
• Two studies estimated a change in the ground water storage within their respective study
areas. One reported a decrease in alluvial aquifer storage of 0.7 kaf/yr in Water District 64
(1947-1961). The other study reported a decrease in alluvial aquifer storage of 19 kaf/yr
between Henderson and Julesburg (1947-1970).
Other
• Ground Water Pumping
Ground water pumping, although not a water budget component, was estimated in the studies
ranging from 22.8 kaf/yr in Water District 64 to 1,200 kaf/yr in the South Platte River basin in
the state of Colorado. These values are included in Table 1 for reference purposes.
Comments and Concerns
Complete water budget analyses were not identified for the basins in the SPDSS study area. The
availability of only certain water budget components from previous studies shifted the focus of
Task 82 to a review of those pieces of published water budget data that may translate into use
over the entire SPDSS basins of interest. A benefit of this task was to develop a better
understanding of work previously developed regarding water budgets within the SPDSS study
area. Other analyses will be necessary to develop some of the inputs for the initial water budgets
in Task 83.
Task82 final.doc 7 of 7 Apri17, 2005