WSPC04476

• File Number: 8283.200
• Description: Colorado River Basin-Colorado River Computer Models-Colorado River Decision Support System-RAY
• State: CO
• Water Division: 5
• Date: 12/29/1993
• Title: Hydrosphere-Colorado River Model-Technical Overview
• Water Supply Pro - Doc Type: Report/Study

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002106
Hydrosphere's Colorado River Model

December 29, 1993
Page 13

Metropolitan Water District

California's basic entitlement of 4.4 maf per year includes 550 kaf held by the
Metropolitan Water District (MWD), an agency that supplies water along the southern coastal
region including the Los Angeles area. This diversion holds fourth priority (priority-4) among
California diverters under the California Seven Party Agreement. Since quantification of this
right, miscellaneous present perfected rights and federal reserved rights have been quantified,
with the result that only 497 kaf of MWD's priority-4 right falls within California's 4.4 maf.

The CRSM data set reflects assumptions about how rapidly competing rights will
develop and how quickly MWD will be able to obtain alternative sources of supply from other,
senior California users. The data assume that MWD will be able to obtain 106 kaf from its
current conservation agreement with the Imperial Irrigation District and will be able to obtain
another 100 kaf from similar agreements with lID or other diverters. Thus MWD's right is
quantified at 703 kaf in 2040. It is important to note that the data thus incorporate partial
implementation of one mechanism for coping with projected supply shortfalls.

In addition to MWD's priority-4 entitlement, the agency holds two additional water
rights totalling 662 kaf. With the priority-4 MWD entitlement set at 703 kaf for year 2040,
only 636 kaf of aqueduct capacity remain (1.339 maf total capacity). Hydrosphere's Colorado
River Model allows for the specification of an "excess" MWD diversion sufficient to fully
exploit MWD' s remaining capacity in the Colorado River aqueduct. These excess diversions
are made available to MWD from time to time under the surplus provisions of the operating
criteria. When excess diversions are available, they bring California's total depletions to
between 5.04 and 5.17 mafper year. Alternative depletion schedules for MWD and other
California diversions can be input to the model.

Hydrosphere Resource Consultants 1002 Walnut Suite 200 Boulder, Colorado 80302