UTAH CLOUD SEEDING ACTIVITIES

For the water year 2012, Utah has three large-scale projects using silver iodide:

1. Central/Southern Utah/Tooele County Project Areas
• Sponsored by the Utah Water Resources Development Corporation.
2. Northern Project Areas
• Sponsored by Bear River Water Conservancy District and Cache County.
3. West Uintas Project Area
• Not seeded this year. Sponsors were concerned about residual snow and moisture
4. Uinta Mountains Project Area
• Sponsored by the Central Utah, Duchesne County, and Uintah Water Conservancy Districts.

Utah also has one small scale project using propane:

Emery and Sanpete Project

• Sponsored by Emery Water Conservancy Distric

Emery Water Conservancy District is operating a small scale project using liquid propane to seed the Wasatch Plateau above Joes Valley Reservoir. This will be enlarged to include portions of San Pitch River Drainage.  The estimated cost for this project is $61,200, of which the state will cost share $30,600 (50 percent).

The Central/Southern Utah Project has operated continuously since water year 1974, with the exception of the extreme wet period from 1984-87. The project has 34 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.

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 2011. There are 27 seeded seasons. The project area has seven cloud seeding generators. Target and control regression analysis show a December-March precipitation average increase of 12 percent.

The East Box Elder/Cache County Project Area has operated 23 years beginning in 1989. The project area had 22 cloud seeding generators from 1989-2001. Bear River Water Conservancy District (Box Elder County) did not participated in the project for the 2002 and 2003 seasons, limiting the project to 15 cloud seeding generators during this period.  The project was back in full operation for the 2004 to 2011 seasons and will continue this year.  Target and control regression analysis shows a December-February precipitation average increase of 18 percent.

The West Box Elder Project Area has operated seventeen years.  It was operated from 1989 through 1997, and 2000 through 2001. The project was not operated in 2002 and 2003 seasons.  The project was operated during the 2004 to 2011 seasons and will continue this year.   The project area has 10 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 15 percent.

The West Uintas Project Area operated for nine years from 1989 through 1993, plus 1995, and 2001 through 2011. It will not be operated this year. Weber Basin and the Provo River Water Users Association chose not to participate this year.  The project area has had 14 cloud seeding generators.  Target and control regression analysis show a December-March precipitation average increase of two percent.

The Uinta Mountains Project Area operated for the years from 1975-1987.  It was operated again for the years 2003 to 2011.  It will be operated again this year.  The project area has 24 cloud seeding generators.  Target and control regression analysis showed a December-April precipitation increase of four per cent.

The table below shows a summary of the cloud seeding project areas operated last year.  A map showing the location of the cloud seeding generators for the 2010-2011 Season follows.

A study dated May, 2005 by the Division of Water Resources estimated an average annual increase in runoff of 223,000 acre-feet making the total cost of water developed approximately $1.70 per acre-foot.