SPDSS_Task46-2_StreamGainLossEstimates

• Title: SPDSS Task 46.2 - Stream Gain/Loss Estimates - Phase 4
• Description: This Technical Memorandum summarizes the compilation and analysis of data for the computation of monthly gains and losses for the main stem of the South Platte River and selected tributaries for the study period of 1950-2005.
• Decision Support - Doc Type: Task Memorandum
• Date: 4/10/2008
• DSS Category: Groundwater
• 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: CDM

^ Tlne monthly baseflow averages developed for each reach are appropriate characterizing
stream gain and losses over time wiflnin each reach and should be used to assist in the
model calibration being conducted under Task 48 of the SPDSS.
Several steps could be taken to improve the accuracy of the baseflow estimates if
necessary for localized analyses. These could include additional gaging to better
quantify the currently wngaged unflows and outflows (such as small municipal
dischargers and farm rwnoff), and including smaller-volume inflows and outflows. Tlnis
detailed information was not necessary for tlne purposes of finis regional analysis.
6.0 References
CDM (Camp Dresser & McKee Inc.) 2006. SPDSS Phase 3 Task 43.3 South Platte Alluvium
Region Aquifer Property Technical Memorandum, Prepared by CDM for the CWCB. December.
Colorado Division of Water Resources (CDSS), 2007. Straightline Diagrams.
htt~://water.state.co.us. May.
Glover, R.E. 1974. Transient Ground Water Hydraulics. Water Resources Publications. Fort
Collins, C0.413p.
Hurr, R.T. and Schneider, P. 1972a. Hydrogeologic Characteristics of the Valley Fill Aquifer in
the Brighton Reach of the South Platte River Valley, Colorado, USGS Open File Report 72-332.
. 1972b. Hydrogeologic Characteristics of the Valley Fill Aquifer in tlne Greeley Reach
of the South Platte River Valley, Colorado, USGS Open File Report 73-124.
. 1972c. Hydrogeologic Clnaracterishcs of the Valley Fill Aquifer in the Weldona Reach
of the South Platte P`iver Valley, Colorado, USGS Open File Report 73-127.
. 1972d. Hydrogeologic Characteristics of the Valley Fill Aquifer in the Brush Reach of
the South Platte P~iver Valley, Colorado, USGS Open File Report 73-123.
. 1972e. Hydrogeologic Characteristics of the Valley Fill Aquifer in the Sterling Reach
of the South Platte River Valley, Colorado, USGS Open File Report 73-126.
. 1972f. Hydrogeologic Characteristics of the Valley Fill Aquifer in the Julesburg Reacln
of the South Platte River Valley, Colorado, USGS Open File Report 73-125.
Leonard Rice Engineers, 2006. Phase 3 Task 2-Identify Key streamflow gages and estimate
Streannflows for Missing Records, Prepared by LRE for the CWCB. September 20, 2004 -
Revised August 21, 2006
Leonard Rice Eng>neers, 2006. Phase 3 Task 5-Key Reservoirs, Prepared by LRE for fine CWCB.
July 1, 2005 -Revised December 19, 2006
SPDSS Phase 4 Task 46 Technical Memorandum -Final 17
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