WSP06035

• File Number: 8460.500
• Description: Platte River Recovery Plan - SPDSS Studies ‎(see also 8483)‎
• Basin: South Platte
• Date: 1/1/1998
• Author: Colorado State Univ.
• Title: South Platte Consumptive Use ‎(CU)‎ Model User Manual - Version 1.1
• Water Supply Pro - Doc Type: Publication

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User Manual - Consumptive Use Model

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2.5.1 Evaootransoiration Estimation lET) Methods
The CU Model currently allows users to select two methods for estimating ET, Blaney-Criddle and
Kimberly-Penman. Daily methods (Penman-Monteith) can be added depending on the needs of the user, but
are not supported in this version. The Blaney-Criddle is a monthly method developed initially by the Soil
Conservation Service and uses temperature, precipitation, and crop data. The Kimberly-Penman calculates
monthly ET using an energy balance plus heat and mass transfer. Select the desired ET method by clicking
on the down arrow and then click on the ET method.

Simulllljon~YeaLRan!ile'. ~: ~'

ETMethod:

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!Kimberl.Y.Penmen
Blane -Criddle

.rJ

91;';/

Penman.Monteith
. USeA

< v~;"":We~ihe,~D'~I~1

Figure 3: ET Estimation Methods

2.5.2 Monthlv Precioitation Methods
Two precipitation methods can be used for estimating ET:

. SCS - Precipitation method, based on the Natural Resources Conservation Service (formerly Soil
Conservation Service) methodology, in which effective rainfall is dependent on the net depth of
application and the average monthly consumptive use.

. USBR - Precipitation estimation method, based on U.S. Bureau of Reclamation methodology, in
which effective rainfall is linearly related to average monthly rainfall. Different linear relationships
are used for different ranges of rainfall.

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2.5.3 Winter PreciDitation Carrv-over
Winter carry-over soil moisture is the percent of winter precipitation that will available to crops in the
Spring. The amount of water specified for winter carry-over will contribute to the consumptive use of crops
during the growing season and therefore will off-set some of the requirements of surface or groundwater
supplies.

2.5.4 Viewinl! and Editinl! CroD Coefficients
The Crop Coefficients window allows you to view or edit crop coefficients. Crop coefficients
(typically referred to by the variable KC) to determine the consumptive use of a crop for a certain time
period be including a factor to account for differences in consumptive used characteristics from the
reference crop. For some of the crops the period is in percentages of the growing season and others are in
days of the growing season.

ClOp Coclhclcnts tJ

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Period
1
"15
."
4S
60
74
91
105
121
_ 135

- ,KG
0.'
0.63
0.68
0.13
0.79
0.85
0.92
0.99
1.045
l09

,--c-
-~ r,:

<::' ''''',','>i',:,
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,- - ane. ob;7~ if.,--'
" . '^"--~-,-Vi-

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,,,-::-l:Ie_~'fj ,,~c::::: i/X"

Figure 4: Crop Coefficients Window

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Version J.J

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