SPDSS_Task59-1_Develop Locally Calibrated Blaney-Criddle Crop Coefficients

• Title: SPDSS Task 59.1 - Develop Locally Calibrated Blaney-Criddle Crop Coefficients
• Description: This memorandum presents the recommended regional Blaney-Criddle crop coefficients for use in the SPDSS CU analysis. Revised January 11, 2008
• Decision Support - Doc Type: Task Memorandum
• Date: 1/11/2008
• DSS Category: Consumptive Use
• DSS: South Platte
• Basin: South Platte
• Contract/PO #: C153954
• 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

Because the principal crop grown at high elevations in Colorado is pasture or meadow grasses,
these studies focused on the PCU of high altitude grasses (Table 1 and Figure 1).
Table 1
Lysimeter-Derived Grass Crop Coefficients 1
(for use with the Original Blaney-Griddle Method)
L simeter Stud A r Ma Jun Jul Au Se Oct Elevation
South Park -LRCWE 0.58 1.11 1.28 1.26 1.07 1.14 0.78 ~ 9500'
South Park -Walter - 1.18 1.40 1.22 0.81 0.86 0.75 ~ 8900' - 9420'
So Park -Kruse - 0.996 1.163 0.983 0.729 0.890 - ~ 9100'
Div 6 -CYCC - 0.93 0.96 1.02 0.92 0.79 0.86 ~ 6670'
Div 6 -Catamount - 0.74 0.93 0.84 0.73 0.71 0.78 ~ 7000'
Div 6 - No Park (Walden) - 0.87 1.13 1.12 0.97 0.86 - ~ 8220'
Grand County - 1.05 1.08 1.01 0.83 0.98 - ~ 7500' - 7850'
Gunnison -Kruse - 1.253 1.095 0.959 0.908 0.988 - ~ 8000' - 9100'
Gunnison -Smith - 1.24 1.42 1.13 0.82 0.87 - ~ 7774' - 8685'
Lysimeter-derived crop coefficients used to estimate potential crop consumptive use under full water supply
conditions.
1
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Apr May Jun Jul Aug Sep Oct
So Park -LRCWE -So Park -Walter -So Park -Kruse
Div 6 -CYCC -Div 6 -Catamount -Div 6 - No Park (Walden)
Grand County Gunnison -Kruse -Gunnison -Smith

Figure 1- Lysimeter-Derived Grass Crop Coefficients
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