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000148 Transport and diffusion studies will be conducted at each selected subbasin for a minimum of two winter seasons. The studies will use both ground-base generators and seeding aircraft to provide nuclei; instrumented aircraft will trace the resulting plumes. Networks of surface-based sensors will measure such variables as wind velocity, wind direction fluctuations, and distribu- tions of surface temperature. Seeding opportunity recognition studies will use observations of supercooled water, ice crystal concentrations, precipi- tation, and storm characteristics to estimate the number and duration of treatable events likely to occur during a typical winter season. The studies will help specify the design for subsequent operational projects in these subbasins. The possible existence of seeding-induced effects beyond the primary target area has coequal standing with analysis of in-target effects. The CREST Program will address two important issues. The first concerns whether seeding affects snowfall in regions immediately downwind of the areas tar- geted for precipitation augmentation. The second issue is whether seeding may alter the development of storm systems as they pass beyond the target areas and move into the lee of the Rockies. Scientific studies in other areas over the last two decades have shown no evidence of significant decreases in downwind precipitation; on the contrary, there is some evidence of precipitation increases 100 kilometers or more from the target area. The CREST extra-area-effects progra~ will concentrate on the analysis of precipitation in downwind areas to clarify the existence and nature of such effects. Precipitation gages will be placed on the lee Slopes of target ranges and in the heavy snowbelts of immediate downwind ranges. Studies of the area in the lee of the Rockies will use data from the National Weather Service Stations. In addition, snow samples from these downwind areas will be analyzed for seeding material content. Mesoscale cloud models will be used to investigate possible effects on storm development. An environmental assessment has been prepared for CREST. It concludes that, on the basis of research accomplishments and operational programs conducted to date, a Finding of No Significant Impact is appropriate for the 8-year demonstration program. It recognizes that when the specific demonstration areas are selected at the conclusion of the public involvement process following authorization and funding, site-specific environmental assessments for matters such as community impact, local environmental concerns, and endangered species will be accomplished. Environmental and social components are important factors in making the decision about proceeding with an opera- tional program, and will be monitored during CREST. Three types of advisory committees are planned for the CREST Program: (1) a Basin group with specific interests in water management and legal questions, (2) local groups to be involved in site selection and community response, and (3) a scientific/technical group. The first group, a Basin States organiza- tion, was established at the request of the Commissioner of Reclamation at a meeting with the States in December 1981. The other groups will be set up when CREST is approved. CREST will be conducted by a combination of Reclamation (Bureau of Reclama- tion) and contractor personnel and will require the services of engineers, 4 ----.