PART VI — PRECIPITATION AND REGIONAL WEATHER PHENOMENA 



Furthermore, precipitation augmen- 

 tation affects other natural resources 

 besides water. For example, an in- 

 crease in precipitation will have an 

 effect on the natural plant and animal 

 communities in and around the target 

 area. Extra water on the soil may 

 bring additional lands into grazing 

 capability, but it may also hasten the 

 leaching of nutrients. The availabil- 

 ity of additional water may cause 

 changes in man's use of the land. He 

 may change the kinds of crops he 

 grows. He may reap greater harvests 

 from smaller acreage. None of these 

 effects, however, is expected to be 

 large. 



Potential Benefits — The interac- 

 tions between man, his institutions, 

 and precipitation augmentation are 

 important. The direct benefit of addi- 

 tional precipitation is that it helps to 

 assure an adequate supply of water 

 for municipal, industrial, and agricul- 

 tural uses. Secondary benefits include 

 the generation of low-cost electricity 

 and assistance in abating air and 

 water pollution. Relatively small op- 

 erational projects for water supply 

 and power generation have existed 

 for years. What is needed is an in- 

 tegrated program in which many 

 benefits can be realized from one ac- 

 tivity. 



Potential Liabilities — Precipitation 

 augmentation does have associated 

 liabilities. A few people object to any 

 deliberate tampering with nature, 

 some on moral or religious grounds / 

 others simply on aesthetic grounds. 

 Some of those who live or work in 

 the target areas of augmentation op- 

 erations could suffer financial loss, 

 especially where the economic bene- 

 fits are derived some distance away 

 from the target area. Increased pre- 

 cipitation in the form of snow could 

 decrease the growing season and the 

 tourist season. Erosion could increase 

 slightly — although, alternatively, in- 

 creased vegetation from the addi- 

 tional moisture could cause erosion to 

 decrease. Undesirable plant life may 

 increase in certain areas. Increased 



snow could raise snow-removal costs 

 (although an estimate made for the 

 Colorado Rockies indicates no such 

 effect for a 10 to 20 percent snow 

 increase). Potential liabilities exist, at 

 least in theory, in the possible extinc- 

 tion of a few species of flora or fauna 

 and in the modification of river chan- 

 nels. The net value of precipitation 

 augmentation must include determi- 

 nations of the relative importance of 

 man, nature, and their interaction. 



Legal Issues — Precipitation man- 

 agement raises a variety of legal is- 

 sues. Who owns the water in the 

 atmosphere? How should losses re- 

 lated to precipitation augmentation 

 be compensated? How should opera- 

 tions be regulated? How should the 

 money to pay for operations be ac- 

 quired (taxation by water district, 

 state tax, federal funds, etc.)? Should 

 research projects be treated differ- 

 ently from operational projects with 

 respect to liability? When water 

 needs in one state can be helped by 

 precipitation augmentation in an- 

 other, who makes the decisions? 



Normative Issues — There are some 

 reputable scientists who believe that, 

 while seeding does affect certain 

 cloud characteristics, there are too 

 many conflicting results from cloud- 

 seeding experiments to say that ob- 

 served precipitation increases from 

 seeded clouds were caused by the 

 seeding. But the majority of scien- 

 tists who question precipitation aug- 

 mentation ask not "Does it work?" 

 but "Should we use it?" In other 

 words, precipitation augmentation, 

 while far from perfected, is con- 

 sidered by such scientists to be an 

 operational reality. Precipitation aug- 

 mentation today is thus in a position 

 similar to that of nuclear power 

 plants several years ago. Discussions 

 center largely on the risks to people 

 and the environment and on eco- 

 nomic feasibility rather than on sci- 

 entific capability. Answers to these 

 questions await interdisciplinary stud- 

 ies of real and hypothetical situations. 



Requirements for 

 Scientific Activity 



The practical objective of current 

 precipitation -augmentation research 

 is the development of a precipitation- 

 management system. The system in- 

 cludes more than the ability to 

 analyze water needs, recognize op- 

 portunities, treat opportunities, and 

 evaluate results. A fully developed 

 system includes the ability to specify 

 the results of treatment in advance 

 with a high degree of confidence. It 

 includes the ability to specify the 

 areas that will be affected by the 

 treatment, as well as the ability to 

 assess beforehand the environmental 

 consequences. Such systems need to 

 be developed and thoroughly tested. 



To provide solid answers to the 

 many unanswered questions of pre- 

 cipitation augmentation, some im- 

 proved instrumentation must be ac- 

 quired. Some sort of standard nuclei 

 counter is needed. Radar systems 

 specifically designed for weather 

 modification are needed to replace the 

 surplus military equipment now be- 

 ing used. A variety of airborne and 

 surface remote-sensing devices would 

 be useful. Especially needed are de- 

 vices for determining the moisture 

 distribution in the air from the sur- 

 face to about 18,000 feet. Cloud- 

 particle samplers are needed for 

 cloud physics measurements. Several 

 versions are available, but none pro- 

 vides the scientist with all he needs 

 to know. 



Accurate recognition of treatable 

 situations is not yet a purely objective 

 procedure. Better definition of the 

 essential weather conditions is needed. 

 Factors such as moisture flux are not 

 easily measured on the scales needed 

 for precipitation-augmentation proj- 

 ects. Mathematical models and the 

 computers to run them should be an 

 integral part of the recognition sys- 

 tem. Improved instrumentation will 

 be needed to acquire the data for 

 the system. 



The search for more effective treat- 

 ment techniques must go forward. 



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