The Sierra Cooperative Pilot Project (SCPP) is a research effort of the Bureau of Reclamation’s Office of Atmospheric Resources Management (OARM) Project Skywater - in and near the American River Watershed, California. This long-term research program is important to the enhancement of of nation’s future water supply and is part of a larger effort by the Bureau to optimize current cloud seeding technology. A portion of the SCPP involves the siting and installation of of various meteorological instrumentation, the maintenance of that network, the collection and reduction of data from the instrumentation, and the analysis of the data in support of the overall evaluation of the SCPP. The cover photograph shows one of the precipitation gauge installations within the study area. In the snow area, the gages are charged with an antifreeze solution and oil film to prevent freezing and evaporation. Bureau of Reclamation Photograph by: D. M. Westphal.