WMOD00382

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

For both snowpack augmentation and rainfall enhancement, these low costs result ill
benefit/cost ratios of 10: I or better.

Project Skywater's accomplishments have led to a growing awareness and acceptance of
precipitation enhancement as a water augmentation tool. Operational application programs
have been initiated in six states -- Colorado, Kansas, Nevada, North Dakota, Texas and Utah
-- using cloud seeding techniques and local technical groups developed in large part under
Project Skywater. Reclamation has provided technical assistance to these programs to help
transfer weather modification technology from government research to practical application.

DOMESTIC PROGRAMS

Sierra Cooperative Pilot Project (SCPP) - The SCPP was the largest field program of
weather modification research performed by the U.S. Government. The primary goal of this
program was to develop a practical cloud seeding capability for increasing the runoff and
streamflow of the American River Basin of the central Sierra Nevada of California.

The SCPP concentrated on the warm, shallow orographic clouds as the most treatable and
most productive cloud type for producing additional precipitation on the ground. Targeting
of the seeding effects was at a fixed site, high in the Sierra Nevada, equipped with a dual
channel radiometer, Ka band radar, ground microphysics instrumentation, a rawinsonde unit
and other meteorological sensors. This array of scientitic equipment measured the magnitude
of the seeding effect and, with the help of aircraft in situ cloud physics observations,
documented the physical links in the chain of events leading to additional precipitation on the
ground.

The results of the comprehensive SCPP scientific, economic and environmental studies are
currently being analyzed for inclusion in the project's final report.

Sierra Nevada Cooperative Project - Reclanlation is cooperating with the California
Department of Water Resources in its planning for a long-term project to increase streamflow
through snowpack augmentation into Lake Oroville, which is a key component of the
California Water Plan. The present plan is to seed clouds over a portion of the Feather River
Basin, which drains into Lake Oroville. As the Feather River is just north of the American
River Basin, the site of most SCPP experiments, the project design is based on transferring
the SCPP findings to that Basin. As SCPP found that supercooled liquid water in Sierra
Nevada storms is often very close to the ground, ground-based seeding from elevated sites has
been chosen as the mode of operation. In order to reduce costs and the possibility of
environmental contamination, the seeding agent will be liquid propane rather than silver iodide.
Limited scale seeding tests will be conducted to refine and improve the project design which
will form the basis of the long-term operational seeding program to follow.

Colorado River Augmentation Demonstration Program (CRADP) - This Reclamation
research program was designed to improve the already favorable benefit-to-cost ratio of winter
snowpack augmentation in the Colorado River Basin. Activities included studies at the Grand

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