WMOD00382

• Project Name: Project Skywater
• Title: Project Skywater - Water Augmentation through Cloud Seeding
• Date: 7/1/1989
• Weather Modification - Doc Type: Report

Convective Precipitation Experiment (CCOPE) conducted in Montana and High Plains
Cooperative Program (IDPLEX) where field work was carried out in Texas, Kansas and
Montana.

Drought Relief - In the U.S., Reclamation has conducted emergency cloud seeding programs
twice in response to critical drought conditions. In 1972, the Water Augmentation Group
provided the planning, design, contracting and field direction for drought relief cloud seeding
projects in Arizona, Oklahoma and Texas, using funds provided by the President's Office of
Emergency Preparedness.

A second severe drought occurred during 1976-77. The Water Augmentation Group supplied
technical coordination and computer system support and loaned specialized equipment to
States, with funding from the Emergency Drought Act of 1977. Under this Act, Reclamation
granted more than $2 million to California, Colorado, Kansas, Nevada, North Dakota and Utah
for cloud seeding projects to increase rain and snow.

Reclamation's assistance in providing weather modification for drought relief has not been
limited to the continental U.S. In late April 1983, Panama was suffering from a prolonged
drought. Lack of rainfall was seriously threatening the Canal, Panama City's water supply and
water for the city's hydroelectric power. Following an assessment of the situation, a program
was developed and within a few weeks time specially equipped aircraft, experienced crews
and a project meteorologist were on their way to Panama. Between May 31 and August 27,
1983, a total of 109 seeding and observation missions were flown. While there was little
opportunity for scientific evaluation of the results because of the emergency character of the
operation, assessments of available data showed the amount of rainfall per "rainy day" was
slightly increased over the average of the previous 11 years.

RESULTS

Results of Project Skywater research in different meteorological and geographical conditions
have confinued that precipitation can be increased by seeding suitable clouds at the right time.
In addition, accompanying scientific studies have shown that the results are consistent with
hypothesized physical concepts and have provided the basis for improved seeding techniques.
The benefits of seeding winter clouds in mountainous regions are particularly promising.
Several research projects have indicated the potential for a 10 to 15 percent precipitation
increase from seeding winter clouds over the Colorado Rocky Mountains. The resulting
streamflow increases provide additional hydroelectric power generation and salinity reduction
benefits, as well as municipal, industrial and irrigation water supplies and recreation water to
meet a spectrum of needs to maintain quality of life. The water augmentation costs of winter
orographic cloud seeding are estimated at $6 to $8 per acre-foot.

The results of the summer cloud seeding research indicate that convective clouds are complex
and higWy variable. The weather modification technology for these clouds is less well
developed. There is evidence, though, that in some instances seeding of convective clouds can
increase seasonal rainfall by an average of about 10 percent. Seeding costs to achieve this
are estimated at $1 per acre.

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