WMOD00446

• Title: Utah Cloud Seeding Program - Increased Runoff/Cost Analyses
• Date: 2/1/2000
• Weather Modification - Doc Type: Report

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control analyses have also been made for April 1 snow water content. The April 1 snow
water content analyses are important because relationships can be developed to estimate
runoff based on April 1 snow water content.

The Central/Southern Utah project area has operated continuously since wateryear
1974, with the exception of the extremely wet period from 1984-87. The project has had
22 seeded seasons. The project area has 66 cloud seeding generators. Using a target
and control regression analysis for December through March precipitation, the Central/
Southern Utah project area indicates a 14 percent average increase in precipitation for this
period. A similar analysis using April 1 snow water content shows an average increase of
7 percent.

Seeding began in the Tooele County project area in 1976 and continued through
the 1982 water year. Seeding resumed in 1989 through 1992 and again in 1996 to 1999.
The project area has had 15 seeded seasons. The project area has nine cloud seeding
generators. Target and control regression analyses show a December-March precipitation
average increase of 19 percent and an April 1 snow water content average increase of 20
percent.

The East Box Elder/Cache County project area has operated 11 years beginning
in 1989. The project area has 22 cloud seeding generators. Target and control regression
analyses shows a December-February precipitation average increase of 20 percent and
an April 1 snow water content average increase of 18 percent.

The West Box Elder project an~a operated for nine years from 1989 through 1997.
The project area has 12 cloud seeding generators. The target area has no precipitation
gages; however, there are two snow courses. A target and control regression analysis
shows an April 1 snow water content average increase of 18 percent.

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