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<br />percent in the Bridger Range (Montana) and Climax I and II (central Colorado) Experiments were used.
<br />This increase combined with a storm seedability factor of 0.45, estimated from limited cloud modeling
<br />with the Colorado State University three - dimensional Regional Atmospheric Modeling System, yielded a
<br />precipitation seasonal increase of 11.25 percent, the value used to estimate headwaters additional
<br />precipitation.
<br />Estimates of water volume increases were made with an approximate 28 percent areal coverage of the
<br />Headwaters Region resulting from use of a sample seeding design (shown in figure 4.1) and equipment
<br />placement for 55 seeding devices. This number of devices was obtained from brief study of terrain
<br />digital elevation data, wilderness area locations, estimated seeding plume widths and nonlocal winds, and
<br />is strictly a preliminary. assessment. Applying the 11.25 percent increase to average winter precipitation
<br />in the Headwaters Region yielded an additional 60,000 acre -feet of water in the areas above 9000 feet in
<br />elevation covered by the seeding plumes of the 55 seeding devices. For the dry year (50 percent of
<br />normal precipitation), seeding yielded an additional 30,000 acre -feet, and the seeded wet year produced
<br />90,000 additional acre -feet (150 percent of normal precipitation). The increases grow to the respective
<br />85,000, 43,000, and 128,000 acre -feet of water when the areal coverage by seeding devices is increased
<br />to 40 percent through possible seeding design improvements. The design phase of the program will
<br />produce a proper seeding device siting and consequently, seeding areal coverage. These figures are not
<br />adjusted for possibly differing seeding opportunity from one year type to another. Additionally, they do
<br />not incorporate effects of cloud seeding suspension criteria (likely to mostly affect results in wet years)
<br />that will need to become a component of the program's environmental awareness.
<br />The annual cost of the first year of operational seeding is estimated at $1,025,000 and the tenth year at
<br />$1,330,000 using a 3 percent inflation factor per succeeding year. The estimated 10 -year cost of
<br />operations is $11,716,000. Assuming 55 cloud treatment devices are used in seeding, the average annual
<br />cost of operations per seeding device is $21,300. This figure includes annual costs for all operational
<br />tasks, assuming automated conduct of cloud seeding, largely automated collection of field data, no
<br />observations by aircraft or local scanning radar. Weather service routine radar information from the
<br />network's Grand Mesa Colorado system would be available. Cost estimates would be revisited at the end
<br />of the design phase.
<br />The first year of the design phase will be devoted to planning, weather and cloud modeling,
<br />environmental compliance and permitting, study site selection for the design phase, preliminary
<br />surveying of the Headwaters Region, and contract procurement. The following two years will entail
<br />field data collection for two winters, data analysis, additional weather and cloud modeling, equipment
<br />specification and siting determination, environmental compliance, and public involvement. The cost of
<br />conducting the design phase effort, including environmental compliance estimated at $275,000, but short
<br />of equipment costs, is $1,498,000 for the three years. Total equipment costs are estimated at $1,800,000.
<br />The seeding equipment is estimated at $1,369,000.
<br />Weather modification programs must comply with National Environmental Policy Act (NEPA)
<br />requirements if they include financial or regulatory participation by the Federal Government, or affect
<br />lands managed by Federal agencies. The proposed program faces compliance for the design phase
<br />possibly at a low complexity level, but because precipitation increases are expected in the operational
<br />seeding phase, compliance for it may be at a moderate to high complexity level requiring data collection
<br />and analysis. No cloud seeding or significant disturbance of ground or vegetation can occur until NEPA
<br />requirements are met. An interdisciplinary team of experts will be needed. Public involvement will be
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