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<br />000110 <br /> <br />winter operational cloud seeding program; seeding storms passing over the <br />Sierra Nevada - including specially identified public lands such as <br />wilderness areas - without incident or indication of harmful environmental <br />effects or social inconvenience. <br /> <br />In the State of Colorado, the 5-year Climax I research program was initi- <br />ated in 1960 by Colorado State University. Climax II was conducted from <br />1965 to 1970. "These studies identified a potential snowpack increase of <br />between 10 and 20 percent when winter seeding was conducted under speci- <br />fied conditions." [15, p. 3]. The Colorado River Basin Pilot Project was <br />conducted by the Bureau of Reclamation in the San Juan Mountains from 1970 <br />to 1975. It confirmed the results of the Climax Studies. <br /> <br />An array of municipalities, counties, public utilities, ski areas, private <br />companies, water management organizations, and Indian tribes have con- <br />ducted operational wintertime cloud seeding in Colorado since 1972 under <br />permit from the State Department of Natural Resources. In drought peri- <br />ods, the State of Colorado has conducted a cloud seeding program [15]. <br /> <br />All these research and operational programs have been conducted safely, <br />without indication of harmful environmental effects. The information and <br />experience gained from these projects create a presumption in favor of the <br />ability of the Bureau to conduct a cloud seeding demonstration program in <br />any of the CRB subbasins in a safe and beneficial manner. <br /> <br />All investigations to date have concluded that incremental increases in <br />precipitation over the short terms of cloud seeding research and develop- <br />ment programs do not have significant adverse effects on various environ- <br />mental ecological sectors. The primary reason cited for this conclusion <br />is the fact that the incremental increases each year are well within <br />historic annual variations in precipitation. The San Juan Ecology Report <br />[14] found a large, natural annual variability of over 400 percent in <br />snowpack. As additional information and experience has accrued, estimates <br />of long-term impacts of precipitation enhancement have been moderated. <br />The complexity of this analysis question was recognized in 1977 by Howell: <br /> <br />"It has come to be recogn i zed that, in the sett i ngs so far <br />investigated, the potential disturbing effect of weather <br />modification is overwhelmed by other disturbances to the <br />status quo, some manmade and some natural. <br /> <br />"From this state of affairs, two broad conclusions are now <br />being drawn. First, since investigation of the points of <br />specific environmental impact thought to have the highest <br />potential for effects from weather modification has indicated <br />no clearly adverse effects, emphasis on hurry-up studies to <br />ward off imagined catastrophes, such as species extinctions, <br />no longer appears justified. Second, assessment of long-term <br />effects of weather modification on the environment as a whole <br />is assuming relatively greater importance, and means for such <br />assessment are under review." [16] <br /> <br />13 <br /> <br />-~------ <br />---~~-~---~ <br />