WSP13037

• File Number: 8280.10
• Description: CREST - Colorado River Enhancement Snowpack Test
• State: CO
• Author: Unknown - Crest members/BOR?
• Title: Briefing Document for the Colorado River Enhancement Snowpack Test
• Water Supply Pro - Doc Type: Report/Study

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II. PROPOSED ACTION AND ALTERNATIVES

The action proposed by Water and Power is to seed winter storm clouds in the
Rocky Mountains of the Colorado River Basin to increase snowpack, runoff, and
streamflow, thereby providing increased water yield to help meet future
resource demands.

A. No Action

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Under this alternative no site-specific activities would occur in the Colorado
River Basin resulting in a design for a Basin-wide operational claud seeding
program. Research into physical processes within storms, development of new
instrumentation for an improved measurement capability, and testing techniques
for real-time analysis and evaluation of results would continue under the
current Water and Power research program budget. This alternative presents
no additional funding requirements and environmental or social impacts are
not expected. Institutional arrangements for administering additional water
supplies are not needed. The disadvantages of the no action alternative are
that weather modification as a nonstructural alternative for augmenting
the Colorado River Basin water supply will not be demonstrated as a usable
alternative. Future development in the Basin may be restricted. In order to
meet the water use anticipated under the terms of the Colorado River Compact,
other methods of augmenting the water supply would be required ultimately.
Delivery of water to Mexico as well as replacement supplies for depletions
resulting from the Salinity Control Program would be impacted.

B. Cloud Seeding

Winter orographic clouds that are not efficient naturally can be seeded to
prOduce increased precipitation. Water and Power has identified five impor-
tant alpine and subalpine watersheds above the 9000-foot elevation that
produce about 75 percent of the Upper Basin's runoff. See figure 1. ihese
areas are the best candidate subbasins for cloud seeding.

Cloud seeding nuclei will be either dry ice or silver iodide. Clouds can
be seeded by aircraft or by ground-based generators. Six high yield
Colorado River Basin subbasins, including the San Juan Basin, have been
identified as candidates for the initial and demonstration phases of the
Basin-wide seeding program.

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1. la-year Program

In this option, the initial 5-year phase allows sufficient time for
tests in two sucbasins to develop the equipment, procedures, and a
design for conducting a randomized seeding program in one subbasin that
wil I permit statistical evaluation. Other tasks include developing
techniques for readily identifying optimum seeaing conditions, deter-
mining how frequently those conditions exist, procurement and instal-
lation of required data collection networks and equipment, and preparation
of environmental and social impact documents and d demonstration design.

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