WSPC01844

• File Number: 8283.200
• Description: Colorado River Basin-Colorado River Computer Models-Colorado River Decision Support System-Ray
• State: CO
• Water Division: 5
• Date: 7/13/1994
• Title: Consumptive Use Modeling-Task 1.14b-Consumptive Use Prototype Development-Phase Iia
• Water Supply Pro - Doc Type: Report/Study

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Task1.14(b)-ConsumptiveUsePrototypeDevelopment ~ '*'-)~

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3. We began porting a former projecfto the SGI that will be used as the basis for the
consumptive use model. This should be finished in two weeks, and so far, most of
the functions of the GUI work well.

4. The GRASS 4.1 has been installed on the SGI for GIS routines to be used with the
consumptive use model.

5. Work has begun on upgrading the project mentioned in (3) to GRASS 4.1 from
GRASS 4.0.

2.4 Users' Manual

2.4.1 First Draft of User Documents
1. Documented existing XCONS2 model including variable definitions and technical
background. These items will be included in the users' manual and the on-line
documentation.

2. Developed the first draft of the technical background section for the agricultural
category of consumptive use. This item will be part of the users' manual and the
on-line documentation.

2.5 Technical Methods for Calculating Agricultural CU

2.5.1 lrrigated Acreage

1. Work has done on establishing a link between spatial characteristics which will be
stored in GIS and the physical and temporal attributes associated with these
characteristics which will be stored in Informix.

2.5.2 Modify XCONS2 Program
XCONS2 was used by the U.S. Bureau of Reclamation to calculate consumptive use
for the Colorado Consumptive Uses and Losses Report forI981-1985. Originally,
XCONS2 was a fortran program designed to estimate monthly crop consumptive use.
The methodology was developed by Joe Wensman of the Pacific Northwest regional
U.S. Bureau of Reclamation office.

The XCONS2 methodology is based on the SCS Modified Blaney-Criddle method to
estimate the evapotranspiration (ET) as described in the U.S. Department of
Agriculture Soil Conservation Service's, Irrigation Water Requirement, Technical
Release no. 21, revised September 1970 (TR21-70).

The fortran program for XCONS2 was reorganized by IDS, but the original
functionality has not changed from the 1981 U.S. Bureau of Reclamation version. The
IDS revised copy has been provided to the U.S. Bureau of Reclamation to test and
possibly adopt for future use.

The XCONS2 methodology will be available to the user of CRDSS to provide some
verification of the system and the replication of the U.S. Bureau of Reclamation
Consumptive Uses and Losses Report results.

XCONS2 is used extensively by the USBR for estimating the monthly Et and CIR,
and has 20 readily available crop coefficient curves which can be easily modified for
any location of interest. This model is currently used to prepare the Colorado River

7/13/94 - Draft of Task Memorandum

9

IDS Group, CSU