WSPC00025

• File Number: 8283.200
• Description: Colorado River Basin-Colorado River Computer Models-Colorado River Decision Support System-Ray
• State: CO
• Water Division: 5
• Date: 4/1/1994
• Title: Consumptive Use Modeling-Recommendations for Appropriate Changes to the USBR Methods Manual Used in Preparing the Consumptive Uses and Losses Report-1985-1990
• Water Supply Pro - Doc Type: Report/Study

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industrial, fish and wildlife recreation and export. This report will addres~recom-
mended changes to the USSR methods utilized to determine consumptive use and losses
in Colorado.

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In the Technical Appendix, consumptive use and losses of irrigated agriculture and
reservoir evaporation is calculated and subtotaled by hydrologic units (USGS, 1992). The
USSR's hydrologic units are hydrographic in nature and with a few exceptions have the
same boundaries as Colorado's former water districts.

Table 1 was summarized from the June 1991 report and shows Colorado's average
annual water use for the 1981-1 985 period.

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TABLE 1
COLORADO'S AVERAGE ANNUAL WATER USE
COLORADO RIVER BASIN
PERIOD: 1981-1985

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AMOUNT PERCENT OF
TYPE OF USE (ACRE-FEET' TOTAL USE
Reservoir Evaporation 82,800 4.2
Irrigated Agriculture 1;365,700 68.6
Municip"sl & Industrial 41,700 2.1
Fish & Wildlife 0 0
Export 603,900 26.3
I Totsl I 1,994.000 I I

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CONSUMPTIVE USE AND lOSSES FROM IRRIGATED AGRICULTURE

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It is very apparent in Table 1 that irrigated agriculture accounts for the major
portion of consumptive use and loss in the Colorado River basin in Colorado. Therefore,
the primary focus of the investigation was on the procedures used to determine
consumptive use and losses from irrigated agriculture. Agricultural use is broken down into

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