CRDSS_Task1_14-4_CUModelsNotInShortList

• Title: CRDSS Task 1.14-4 Consumptive Use Model - Consumptive Use Models Not Included in the Short List
• Description: The purpose of this task memorandum is to describe the reasons for excluding the consumptive use models that were evaluated but not considered as part of the "short list." The short list is composed of five models that went through a more rigorous evaluation than the other models.
• Decision Support - Doc Type: Task Memorandum
• Date: 1/9/1995
• DSS Category: Consumptive Use
• DSS: Colorado River
• Basin: Colorado Mainstem
• Contract/PO #: C153658, C153727, C153752
• Grant Type: Non-Reimbursable
• Bill Number: SB92-87, HB93-1273, SB94-029, HB95-1155, SB96-153, HB97-008
• Prepared By: Riverside Technology inc.

and meadow grass ET, and it requires crop phenological data for all crops in the CRDSS, which may be
difficult to obtain.
Eto
Eto was developed by the University of California at Davis, Department of Land, Air and Water
Resources by R.L. Snyder and W.O. Pruitt. This model is user interactive, written in Quick Basic, and
runs on an IBM-compatible PC. The model estimates monthly ET for grass as a reference crop using 10
different ET methods ranging from combination methods to Pan A evaporation methods.
The main reasons for disqualifying this model for use in the CRDSS is that it is written in Quick Basic,
which cannot be run on a UNIX system; it would need significant effort to be converted to FORTRAN; it
does not estimate CIR; and it is not a public domain model. In addition to these concerns, crop
coefficients cannot be added or changed, the model cannot be locally calibrated and then applied to the
entire CRDSS area, and effective precipitation is not included in the input.
WAT 90
WAT 90 was developed by the USBR, Denver Office; the technical contact is Dave King. This model is
user interactive, runs on an IBM-compatible PC, and was written in Basic. The 1982 Kimberly-Penman
and Hargraves methods are used to estimate the daily ET for an alfalfa reference crop. The model also
calculates the CIR by considering effective rainfall and irrigation losses. The main design function for
this model is to estimate daily and monthly CIR, irrigation scheduling, and forecasting charts using
weather and crop data.
The main reason for excluding WAT 90 from the short list and further consideration is that it was written
in Basic with an interactive mode that cannot be moved to a UNIX platform without a costly conversion
to FORTRAN.
Initial Evapotranspiration Models Evaluation
Table 1 shows the results of evapotranspiration models evaluated and eliminated from consideration.
TABLE 1
EVALUATION OF MODELS EXCLUDED
FROM CONSIDERATION
Criteria PEAKWRNCONUS2EtoWAT90
1. Agency and USBR, Mike Madigan USBR (Great Plains UC-Davis, Bill Pruit t USBR, Dave King
Contact [phone] Region), Rick
DeVore
2. What is the FORTRANFORTRANQuick BasicBasic
programming
language?
3. What is the CDC Cyber Main VAX 20IBM-PCIBM-PC
original development Frame
platform?
4. Methods used to Jensen-HaiseSCS Blaney-Criddle 1, 2, 3, 4, 6, 7, 8, 9, Penman- Kimberly-
calculate ET (See and Jensen-Haise and 12 from table 1 1982 and Hargraves
table 1 for detailed in the overview task
description) memorandum
2
A275 01.09.95 1.14-4 CSU IDS