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equipment must test new field equipment and operational procedures on a limited -scale basis. The use of <br />propane release for seeding clouds has never been tested in the high altitude zones of the Headwaters <br />Region. Scaling from an initial deployment of several test propane dispensers to a desired number is <br />considered the proper approach. Prior to deployment of an entire seeding network, answers must be <br />determined regarding seeding mode, targeting and seeding equipment siting for various components of <br />the varying terrain of headwaters barriers. It is recommended that successful operations be achieved in a <br />' limited scale network consisting of two seeding zones before large -scale deployment is pursued. <br />The prototype seeding project studies should involve weather forecasting and cloud modeling. Field data <br />collection should include the monitoring of SLW at propane dispensers and AgI generators (if used), and <br />the measurements of ice crystal in the target areas with simultaneous monitoring of natural crystals, either <br />crosswind of the seeded ice crystal plumes or in established control areas. Some local wind <br />measurements should be made with heated sensors, and some accurate air temperature and dewpoint <br />temperature observations should be obtained at dispenser and crest line elevations. A network of high <br />resolution precipitation gages should be deployed with proper protection from wind effects in selected <br />' forest clearings (Brown and Peck 1962). These gauges will provide relatively accurate high - resolution <br />snow water equivalent observations in seeded and control areas. These measurements should provide the <br />basis for a useful physical evaluation of seeding effectiveness. <br />�J <br />Ll <br />1 <br />1 <br />d <br />1 <br />Because significant electrical power will be needed to operate some of the instrumentation, such as <br />heated wind sensors, it is recommended that a primary prototype testing site be located (via permission <br />and /or cooperative agreement) possibly at the Desert Research Institute's (University of Nevada at Reno) <br />Storm Peak Laboratory, that is equipped with electrical power and is accessible via Steamboat ski lifts <br />and by snowmobiles. The laboratory has shelters for instruments and data collection by technicians. A <br />second prototype site should be. selected and instrumented possibly at a somewhat lesser level, but must <br />also be accessible by 4 -wheel drive and /or oversnow vehicle. Currently, the Storm Peak Laboratory is <br />manned periodically during winters to collect cloud and aerosol data. Observations by aircraft mounted <br />instrumentation are not recommended as a necessary data collection component because aircraft can <br />rarely operate low enough in orographic clouds to provide desired observations. However, any agency <br />willing to supply an instrumented aircraft and personnel to collect data will be encouraged to do so. <br />Because natural snow showers will sometimes mask seeding effects, randomization should be used on <br />some test seeding trials of the design phase. The randomization scheme should be determined after some <br />modeling studies are conducted and the terrain has been surveyed and analyzed. Should the two -year <br />field testing have normal or above seeding opportunities, there may be an opportunity to collect adequate <br />treatment and control samples for a seeding effect statistical assessment on precipitation. Generally, <br />contamination of the control will not be a significant problem with the propane seeding approach because <br />topography will largely control the transport of seeded ice crystal plumes. Only a brief residual seeding <br />effect will occur downwind from the propane dispensers as seeded crystals are transported out of the <br />target area. Propane seeding will not have the long- distance ice nucleation "contamination" that may <br />occur with AgI releases in which nucleation may occur well downwind. However, it may be found that <br />certain zones of the Headwaters Region are best suited for AgI seeding. The seeding design should not <br />eliminate this possibility. <br />An appropriate "buffer zone" of at least 3 miles wide should separate the two prototype study zones. The <br />number of seeding devices per prototype site should be determined after some modeling studies and <br />terrain inspection have taken place. The areas downwind from each seeding equipment zone should have <br />similar instrumentation. Experimental units should be aimed at 1 -3 hours in duration to help minimize <br />natural temporal variations. Delays between experiments must be specified to allow for flushing of <br />previous seeding effects. The test seeding trials should gradually work toward automation that requires <br />13 <br />