WMOD00301 ‎(2)‎

• Title: Conceptual Plan to Develop Water Augmentation by Weather Modification in the Colorado River
• Date: 5/14/1979
• Weather Modification - Doc Type: Report

D R AFT

E. Downwind Effects

What effect cloud seeding in one area has on another area is a
question commonly asked about weather modification. The Workshop on
Total-area Effects of Weather Modification 33/ has reported that
a posteriori analyses of past wintertime cloud seeding projects
indicatel that precipitation changes in extended areas ten~ to be of
the same sign (increase or decrease) and roughly the same magnitude
as target area effects. It should be noted, however, that there is
very little evidence that precipitation increases in one area will
result in corresponding and compensating decreases in some other or

"downwind" areas.

F. Environmental Consideration

Cloud seeding research conducted in the Colorado River Basin, as
outlined in this conceptual plan, will have no significant environmental
effects. To arrive at this determination, a series of studies to
assess the environmental effects of cloud seeding research were
initiated in 1964 and continue at present. The most applicable study
to the Colorado River Basin is the San Juan Ecology Project.

The San Juan Ecology Project was conducted as an integral part of the
Colorado River Basin Pilot Project and investigated ecological
responses to varying snowpack in the San Juan mountains. Specific

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