WMOD00422

• Project Name: Colorado River Enhanced Snowpack Test
• Title: CREST - Environmental Assessment and Design Phase - Finding of No Significant Impact
• Date: 4/1/1981
• Weather Modification - Doc Type: Report

one-third of the area. Extensive outdoor recreation use is made of both
public and private lands.

Historically, the Basin has been sparsely populated. However, the popu-
lation began to increase significantly about 1965. Since the 1980 census,
the increases have been attributed to the so-called Sun Belt phenomena.
However, the most dramatic local population growth patterns are related to
expanding energy development industries. Service industries to serve the
energy and recreation communities also account for a significant portion of
the population growth.

B. The No Action Alternative

The no action alternative presents no impacts due to changes in the
precipitation regime, runoff, streamflow, or water yield in the Basin.
The negative effects due to failure to augment the Basin's water supplies
by cloud seeding mayor may not be offset by other augmentation methods.

C. The Cloud Seeding Alternative

The environmental effects of increasing precipitation by seeding clouds
over a short term (research mode) and over the long term (operational
mode) have been discussed in National Environmental POlici Act compliance
documents. Short-term environmental effects have been discu.ssed in the
Colorado River Basin Pilot Project Final Environmental Statement [7J,
the Project Skywater Programmatic Final Environmental Statement [2J,
and the Sierra Cooperative Pilot Project Environmental Assessment [8J.
Potential effects of widespread and prolonged application of precipita-
tion management wwere considered at the Skywater IX Conference [9J, and
received preliminary evaluation in the Project Skywater Final Environmental
Statement [2J. The studies of the effects of precipitation increases on
ecological sectors in the San Juan Mountains were an important part of the
Colorado River Basin Pilot Project. The results of these studies are found
in the San Juan Ecology Report [10J.

Cloud seeding research activities in the Rocky Mountains, the Sierra
Nevada, the Medicine Bow Mountains, and the Cascades have been accom-
plished without adverse environmental consequences. In addition, many
Western States have supported opey'ational cloud seeding programs or have
issued permits for private sector programs. Certain environmental issues
have been related to winter orographic cloud seeding as a result of
these research and operational experiences. Some of these issues have
been laid to rest by the scientific community. Others will require con-
tinued data collection and monitoring in order to judge their importance
and impact.

An array of historical studies have been concluded that incremental
increases in precipitation over the short terms of research mode cloud
seeding programs do not have significant adverse effects on various
environmental-ecological sectors. The primary reason cited for this
conclusion is the fact that the incremental increases are well within
historic annual variations in precipitation in the study areas. As addi-
tional information and experience has become available, estimates of

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