PROJ00518

• Contract/PO #: C153484
• Contractor Name: San Luis Valley Water Conservation District
• Contract Type: Grant
• Water District: 0
• County: Rio Grande
• Bill Number: FSG
• Loan Projects - Doc Type: Feasibility Study

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With the 1985 spilling of Rio Grande Project Storage, Colorado's accrued Rio Grande

Compact debits were eliminated and the US Supreme Court dismissed with prejudice

the Texas and New Mexico v. Colorado lawsuit.

11.4.3. Basin Water Use

Agricultural activities account for greater than 95% of basin water consumption.

Emery (1973) estimated that 1.4 million acre-feet on an average annual basis (1924-

1969) is consumed by crops in the San Luis Valley and about 1 million acre-feet is

consumed by non-crop vegetation. The total annual consumption (2.4 million acre-

feet) is estimated at 86 percent of the water estimated to be entering the San Luis

Valley.

During the 1961 through 1970 period, Emery estimated that total water diverted from

streams and withdrawn from wells averaged 1.85 million acre-feet per year. Ground

water withdrawals approximate 25 percent of the total water used for irrigation from

1950 through 1969 (Emery,1972). The unconfined aquifer is the principal source of

ground water for irrigation, and in 1969 the unconfined aquifer supplied

approximately 80 percent of the ground water withdrawn from large capacity wells.

Based on USBR compilations of 1950 through 1985 mainstem diversion records for

direct flow water rights, average annual diversions were approximately 520,000

acre-feet. Active administration of the Rio Grande Compact began in 1968 and often

required significant diversion curtailment of Colorado water users.

Table II-4

lists the eleven mainstem ditches with the largest diversions. The ditches in the

following list divert approximately 82 percent of the total direct flow mainstem

diversions, with the Rio Grande Canal itself accounting for approximately one-

third of the total. The following table also indicates whether the ditch diverts

from the north or south bank of the Rio Grande.

The maj ori ty of north bank

diversions are transported into the Closed Basin (see Section V) and produce no
return flows to the Rio Grande mainstem.

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