WSP08695 - Laserfiche WebLink

Home Browse Search

e\ . ., Lecture Notes--1966 Irrigation Opel~tors' Workshop I. Introduction Man daily faces the problem of satisfying his need for water. The West has always been concerned about adequate water supplies, and recently the East, too, has experienced water shortages. Part of the problem today is the misuse of water. However, the time is rapidly approaching ~hen true water shortages will occur .Rhich even the best of conservation practices will not be able to correct. We will then be looking for new sources of water. Ninety-seven percent of the earth's water is in the ocean. More than 99 pprcent of the remaining J pprcent fresh water is retained in the ice caps, glaciers, or underground, leaving less than) per- cent at any moment in the atmosphere, lakes, rivers, and soil. Nevertheless, the tota) precipitation in the United States is tremendous, amounting to about 4.2 trillion gal) ons per day, or 4.75 billion acre-feet per year. Large though this number may be it represents only about 10 percent of thO'! tota) watpr which passes overhead in th~ atmosphere. Think of the potential here: A, What is weather modification? Weather modification is defined in the Glossary of MeteorolQKY as "any effort to alter artificially the natural phenomena of the atmosphere." We are concerned here with the phase of weather modification dealir~ with modifying the notursl precipitotion, which for convenience Me shan call cloud seeding. Cloud seeding o:.fers an opportunity to tap the atmospheric Mater resources. By proper application of weather modification techniques, the total water supplies of the nation can be managed more efficiently. 1. Scientific attempts at weather modification From the time primitive man first hurled incantations to an unknown god to today's research scientist pursuing suspicions in the laboratory and in the field, man has dreamed of con- trolling his environment. Many of his efforts would not be called scientific by today's standards, but man took a significant step up when he first took active measures to protect himself from the whims of nature. While ancient man couJd not prevent rain, he could certsinly minimize its dis- turbing influence on some of his domestic activities. However, he remained virtually powerless to induce the rain. This awaited greater advancements in science. The honor of being the first man to write about weather modi- fication seems to belong to o~e J. Boecler who in 1710 2 89ll