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

long-term effects of precipitation augmentation have been moderated.
The complexity of this analysis question was recognized in 1977 by
Howell:

"It has come to be recognized that, in the settings so far investi-
gated, the potential disturbing effect of weather modification is
overwhelmed by other disturbances to the status quo, some manmade and
some natural.

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"From this state of affairs, two broad conclusions are now being
drawn. First, since investigation of the points of specific environ- .
mental impact thought to have the highest potenti al for effects
from weather modification has indicated no clearly adverse effects,
emphasis on hurry-up studies to ward off imagined catastophes, such as
species extinctions, no longer appears justified. Second, assessment
of long-term effects of weather modification on the environment as a
whole is assuming relatively greater importance, and means for such
assessment are under review." [13, pp. 499-500J

Thus, it is apparent now that long-term monitoring of operational cloud
seeding effects is needed to develop a reliable picture of environmental
effects. Responses of the vegetative regime are of particul ar interest
because of its comparative sensitivity and its key place in the food
chain.

Certain results of cloud seeding, such as increased snowpack, can be
significant and beneficial rather than adverse due to the controlling
factors of the project design and project suspension criteria. Project
suspension criteria precludes cloud seeding activity during weather con-
ditions that could jeopardize public safety or cause environmental damage.
A recent example of development of a suspension criteria system for a
winter cloud seeding project is the experience in the Sierra Cooperative
Pil ot Proj ect. [8, 11J

1. The Initial Phase

As described in Section II of this report, each of the three cloud
seeding options has two phases. In each case, the initial phase
involves installation of meterological and hydrological observation and
data collection networks. Seeding opportunity, climatological studies,
seeding mode studies, ground-based seeding studies, and technology
transfer studies in different subbasins would be included in the initial
phase for the 10- and 8-year options. Environmental and social impact
studies required for the second phase of the program and for the opera-
tional phase would be undertaken.

All meterological and engineering activities conducted during the
initial phase of each of the options are identical to lead-in activities
found in research-mode cloud seeding. These activities are covered by
the Project Skywater Programmatic FES [2J and were discussed in the
Sierra Cooperative Pilot Project Environmental Assessment [8J, and
are also covered by Departmental and WPRS Instructions providing for
categorical exclusions for data collection and other activities of a

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