people who contribute voluntarily to hire a weather modifier to conduct the operations during the growing season.

In that particular area of Texas, some of the people who acquired land there were more fortunate than others, in that they had water beneath this land and are able to irrigate, whereas the others are dry land farmers, and are less prosperous, so there is a kind of built-in resentment in the community between the dry land people and their more fortunate irrigating fellow agriculturists.

The area is semiarid, so moisture is a matter of some concern there. However, early in the project, those who expressed concern about cloud seeding were not included in any discussions. They were not asked specifically what their concerns might be, and those who wanted to have the project, (primarily the irrigating farmers) just went ahead and had it, and then had to deal with the public relations problems created some years down the road, and there was a great deal of bad feeling already in existence.

A number of scientific evaluations have been carried out on that project, and there are hard data to show that rainfall has not been decreased in that area, and that hail has, and so the presentation of that scientific evidence (which was another factor which did not really exist very much in South Dakota), was persuasive to the Texas administrators who grant the permits and licenses in that connection. Apparently it was also persuasive to the judge who presided over the hearing for the injunction down there, and who decided in favor of the continuance of the program.

Mr. BROWN. Who assumed the responsibility for the followup analysis and data collection that provided the information you just cited?

Dr. FARHAR. Scientists from the Illinois State Water Survey, studied the hail patterns in that area of Texas, and published papers, available in the scientific literature, on the effects of that project on local precipitation.

Mr. BROWN. You mean this was undertaken merely as a scientific research project by the Illinois people?

Dr. FARHAR. That is my understanding.

Mr. BROWN. What about the snowpack augmentation project in California? The information we have received seems to indicate that has been a rather uniformly accepted, and apparently successful operation?

Dr. FARHAR. There are a number of projects for snowpack augmentation in the Sierras and other places in California, that have been accepted for as long as 23 or 24 years, and have had no organized public opposition.

I am not altogether sure I can account for that totally, but I do know some of these projects are characterized by, let us say, lack of publicity.

I think there may be some sensitivity on the part of some of the people there that if they make their weather modification activities too well advertised-too public-that it might "stir up the natives.” Mr. BROWN. Well, I would suspect in the area in which the snowpack program operates, there are relatively few people residing there. Dr. FARHAR. Yes, sir. They are not heavily populated areas at all.

On the other hand, California has a rather active environmentalist group, and there might be concerns expressed on those grounds.

Also, the county commissioners or boards of supervisors in mountainous areas are concerned about problems of snow, and there is not really a great deal of research on this kind of question.

Mr. BROWN. I think they just close the highways up there in the Sierras.

Dr. FARHAR. For some of the people who live there, there are such problems as being able to get to a doctor, and so forth.

Mr. BROWN. Your emphasis on the need to include public participation in these experiments, seems to me a rather important one, which I have not seen so heavily emphasized in some of the presentations. Obviously, there is always a complicated and delicate thing to arrange here.

Dr. FARHAR. Absolutely.

Mr. BROWN. I think we will defer any further questions this morning, Dr. Farhar. If we have further questions, we will keep in touch with you, and I hope you can assist us with the written responses. Dr. FARHAR. I will be happy to.

Mr. BROWN. Our third witness this morning is Mr. Robert D. Elliott, president of North American Weather Consultants.

Mr. Elliott has been described to us as perhaps the most experienced private operator in weather modification in the Nation. Are you ready to go?

Mr. ELLIOTT. Yes, I am.

Mr. BROWN. Probably you are the one responsible for that 23 years of successful experience in the Sierras?

Mr. ELLIOTT. That is correct, sir.

Mr. BROWN. You can tell us how you managed to do that.

Mr. ELLIOTT. All right.

Mr. BROWN. The full text of your statement will be included, Mr. Elliott, if you want to summarize any portion of it; or you may read it, as you see fit.

Mr. ELLIOTT. I would like to read it. It is not very long.

Mr. BROWN. Then please proceed.

STATEMENT OF ROBERT D. ELLIOTT, PRESIDENT OF NORTH AMERICAN WEATHER CONSULTANTS, SANTA BARBARA, CALIF.

Mr. ELLIOTT. Mr. Chairman, I sincerely appreciate the opportunity to appear before this committee to present my views on the pending legislation and to provide relevant information on the current state of knowledge and capability in weather modification. I am Robert D. Elliott, president of North American Weather Consultants, a private meteorological firm that has been active in conducting weather modification projects and in providing other forms of environmental services over the past 25 years.

Before commenting upon the two bills that are under consideration at this hearing, I should like to dwell upon some basic aspects of weather modification and upon some of the findings which have emerged since the last great round of hearings on weather modification bills 10 years ago before the 89th Congress.

The primary objective of weather modification as presently practiced is the enhancement of precipitation. It is carried out by seeding suitable types of clouds with artificial ice-forming nuclei, usually consisting of silver iodide smoke particles. Existing methods can produce marginal increases of precipitation, generally around 10 percent, and somewhat higher values in some climatic regions. This may seem rather a small effect to have occasioned so much interest over the past quarter century; however, the economics are such that when seeding is applied toward enhancement of water supplies for hydroelectric power generations, or for irrigations, or is conducted over farm areas for the direct benefit of crops; impressive benefit-cost ratios appear. In the case of hydroelectric power generation, cost of cloud seeding, paid for by the utility industry, runs from less than a dollar to several dollars an acre foot, and the benefits run $3 to $30 an acre-foot, depending upon the type of plant. Other benefits, not so tangible, such as the reduction in the pollution load brought about by substitution of hydropower for fossil fuel power, and just the additional energy made available, are certainly important in these times of environmental concern and energy crisis. The Portland General Electric Co. has stated that on one cloud seeding project in central Oregon, a 10 percent increase in runoff would mean that 100,000 barrels of oil would not have to be burned. There is at present an interest in expanding the Nation's hydroelectric power generation through the harnessing of water power in numerous smaller streams. The potential of cloud seeding to aid in this endeavor is quite significant.

Turning from production of physical energy to production of food energy, we note that cloud seeding to enhance hydroelectric energy production usually also enhances irrigation water supplies downstream. In some cases, cloud seeding to enhance irrigation water supplies is supported directly by irrigation districts. There is a vast potential for benefits to agriculture in dry farm areas. It has been calculated that an extra inch of water on South Dakota cropland is worth about $1 per acre, and this could be provided by cloud seeding at a cost of less than 5 cents per acre. In a drought year the result of seeding-enhanced precipitation might conceivably be the difference between making a crop or not making it.

The elimination of, or at least the amelioration of severe damaging storms, is a subject undergoing study. A national research program to reduce the destructiveness of hail is underway, as is a program to do the same for hurricanes. At present, practical work is underway in reducing hail-crop damage by means of specialized seeding methods. On the other side of the ledger, we have a concern about the social inconvenience of additional precipitation and the possibility of adverse ecological effects. Although no discernable adverse ecological effects have been noted in areas where projects have been conducted on a continuing basis for many years, as long as 25 years in one case; there are currently underway several detailed scientific investigations of possible subtle longer term cumulative impacts on ecology. Thus far. nothing significant has turned up. Calculations of the concentration of silver iodide in the air of a typical cloud seeding target area when full operations are underway shows concentrations to be about 1 to 10 million times under the EPA primary ambient air standards for particulates and the industrial standards for iodine.

Measurements have been made of the silver iodide content of seeding target area snowpack by means of a highly sensitive technique that can detect as little as one part of silver in a quadrillion parts of water. It has been found that concentrations are generally under one per trillion, some 500 times under the Public Health Service limit for iodine in drinking water.

A wildlife association in Montana expressed grave concern at a hearing that a seeding-produced 10-percent addition to the snowpack would have an adverse effect on elk wintering over in the lower reaches of a wilderness area. Figures comparing the reduction in calving rate from a winter with a shallow snowpack to one with deep snowpack did indicate that such an adverse effect could occur simply due to the addition of snowpack. However, a simple calculation showed that it would amount at the most to about a 1- to 3-percent annual attrition rate for the seeding as practiced, and this is quite small compared to the effects of hunting, where the attrition rate is more like 20 percent. Any seeding effect could be compensated by a small change in the number of hunting licenses issued, that is, within the framework of wildlife management procedures. A recent Bureau of Reclamation report indicates that snowpack augmentation in the San Juan Mountains of Colorado would have a minimal effect on forest or alpine ecosystems. This is based upon a 6-year, $1 million ecological field investigation.

Conflicting concerns about water resources and ecology within the Federal Government itself have lead to considerable confusion in wilderness area administration. Here, we have areas set aside by the Wilderness Act to be preserved in their pristine state as much as is possible. On the other hand, these same areas, which are expanding in number at a rapid rate, contain the prime watersheds of the country. It is certainly a matter of national concern that this water be managed, that is, observed, measured, regulated, and where desirable enhanced by cloud seeding; activities now subject to severe administrative restrictions or forbidden by the Forest Service.

Seeding-produced precipitation enhancement, being marginal in degree, is difficult to measure against the large variability present in natural precipitation. It is necessary to conduct randomized experiments in which seeding is carried out during many time intervals having suitable clouds for seeding, with no seeding being carried out during many other such suitable periods. The precipitation patterns are compared for the seeded and not seeded cases in order to determine differences. With only a few cases, a difference could easily appear due to chance. It is only after a long series of trials that a determination of the true seeding effect can be made with confidence. A test project of this type involves some features not found in a conventional operational project. One of these features is the use of a fixed experimental time block for each seeded, or not seeded case.

There have been several important randomized projects carried out in the last 10 years that have added significantly to our fund of knowledge about weather modification. I shall mention two of these with which I have been associated. One was carried out over Santa Barbara County in California for seven winter rainfall seasons-1967-74—and involved the seeding of frontal systems wherein embedded convection, organized into moderately large sized bands, provided the major precipitation mechanism. My firm carried out the project under contract

to the Earth and Planetary Sciences Division of the Naval Weapons Center, China Lake. The evaluation of results showed that precipitation was significantly greater in the seeded than in the not seeded bands.

The second project was carried out for the Bureau of Reclamation over the San Juan Mountains of Colorado. Our contract was for the task of evaluating the results of this very important 5-year project in which the data base consisted of over a million and a half hourly precipitation records from a gage network covering the rugged terrain, over a thousand balloon-borne soundings of the atmosphere taken just upwind of the target area, and many other types of data. In this project evidence for positive seeding effects was found for cloud types where the supply of natural ice forming nuclei within the cloud was inadequate. When there is an inadequate number of natural nuclei, many of the cloud droplets formed by condensation as the air moves up the upwind slopes are not converted to snowfall, but blow over into the downdraft on the lee slopes and evaporate.

Seeding will then make up some or all of the deficit, and the snowfall will be increased. The cloud top temperature is a good index of the concentration of natural nuclei. When it is warmer than about -25°C, there is usually a dearth of such nuclei. When the cloud top is colder than about -25°C, the natural nuclei supply is adequate for the conversion of all of the condensed water to ice crystals, which then fall out over the mountain slopes as snowflakes. Some of the snow will fall on the lee slope where it is carried by the wind. Any seeding at these colder top clouds leads to overseeding, and a reduction of precipitation. The water is spread over many small ice crystals which fall slowly, and are blown over to the lee slope, where many evaporate. Negative seeding effects were shown to have occurred under these cloud conditions in the San Juan project. A parameterized model was developed to simulate the interplay of the various factors. It could be applied in different types of terrain under different types of cloud conditions. Project data from a number of other Bureau of Reclamation randomized tests in different mountain watersheds were subjected to scrutiny by this approach. It was found, among other things, that due to warmer cloud tops and a broader barrier, a much larger fraction of the clouds were suitable for seeding in the Sierra Nevada Mountains of California than in the San Juan Mountains. There were fewer cases where overseeding could occur.

In testimony presented 10 years ago, promise was held out for the further development of computerized mathematical models which could simulate natural and seeded precipitation conditions, and therefore could be used to guide operations and to aid in the evaluation of results. Since then there has been a considerable development of such models, and some seem to simulate in general what happens in the free atmosphere. However, different models can give somewhat different results, and it is necessary to have an abundance of detailed data from randomized test projects in order to validate which models are superior and thus to lay down the correct track to be followed in future model development. It is therefore crucial to have an abundance of high quality field data in hand, not only to determine with confidence what the seeding effects are in a given area, but also to validate models which can then be used to transfer knowledge about seed