WSP09641 - Laserfiche WebLink

Home Browse Search

n~'j"~1 l)J,-,~QL PREFACE Cloud seeding, a ~{dely discussed technological develo?~ent of the second half of the Twenti€th Century, has many facets. One of the more promising is winter cloud seeding aimed at augmentation of snovpack in mountainous areas by artificial inJection of ice-nucleating particles into approaching storm clouds. The upper Colorado Basin, contJining many high ranges of the Rocky Mountain~ along the Continental Divide, has been rp.cognized for some time as a highly suitable localiry for winter cloud seeding technologi- cal and scientific investigation. It is the mure appropriate because one of the longer-term objectives is to find the meanS of increasing water quantity and qua Lity within the entire Colorado River drainage.. With the advances in cloud seeding technology through the t960's and the accompanying increase in understanding of cloud physics, the San Juan Mountains of sQuthvestern Colorado vere selected as an excellent area for large-scale scientific design to test the effi~acy of winter cloud seeding. Thus in 1968 the Division of Atmospheric Water Resources Management of the Bureau of Reclamation began design work on the Colorado Basin Pilot Project with it5 experimental "target area" located in the San Juan Mountains. Concurrent ~ith these technological developments, the Bureau became concerned with their environmental, social, economic, and legal implications. Surveys of the literature on environmental implications beginning in 1964 showed that there was little firm knowledge then available and that speculation was only occasionally based upon fact. By 1968 it had become apparent, however, that the environmental implications should be considered. Thus the Bureau contracted with the University of Michigan for a detailed assess- ment by Charles F. Cooper and William C. Jolly entitled "Ecological E.ffect5 of Weather Modification: A Problem Analysis." In September, 1970, the Bureau awarded a $1,014,000 contract to Colorado State University for the San Juan Etology Project, the subject of this study, to be conducted in cooperation with the Institute of Arctic and Alpine Research of the University of Colorado, and Fort Lewis College, situated at Durango, virtually within the study area. When the San Juan Ecology Project was being planned it was anticipated that artificially-induced sna~fall increases could reach as high as )0 parcent above natural amounts. More recently. ho~ever, a study of potential in- creases in precipitation in twelve western river basins, carried out by North American Weather Consultants, found that an effective technolDgy in the San Juan study area was not likely to produce average annual increases exceeding 10.6 percent of the natural amount. These findings, ho~ever, do not materially affect the course and outcome of the ecology project. The higher figure of )0 percent, assumed possible at the outset, provides a useful upper limit. Also, it had been decided originally that the ecological research ~ould not attempt to monitor the effects of actual artificial increases because a 4 year project (to become 5 years) ~ould not be nearly of Sufficient length for detection of any environmental impacts, even if they should aCCllr in a highly varied complex of mountain environments characterized by great natural variation in annual snowfall. The emphasis was placed upon study of snow-related processes ~~. Thus two primary study areas were developed: analyses of relationships between snow and various components of the San Juan forest ecosystems; in particular, forest phenology. phytosociology, tree biomass and moisture stress, elk, and small mammals; and 0 comparable set of analyses of alpine ecosystem components, including tundra primary productivity, phytosociology and phenology, decomposition, geomorphic processes, small mammals, and boreal toad. To these ~ere added vegetation and geomorphic mapping of the San Juan mountain area and investigation of the disposition and environmental effects of silver iodide, the cloud seeding agent used in the Colorado River Basin Proj~ct. Paleoecology studies were included in an attempt to determine natural environmental fluctuations through time. v