. Principles of irrigation engineering, arid lands, water supply, storage works, dams, canals, water rights and products. Vv-. Fig. 6.—Map showing mean annual rainfall of the United States. The above map shows in a general way the inequalities of distribu-tion throughout the surface of the country being the averages ofobservations carried on through many years. For any singlelocality there is great divergence; during one year there may occurnearly twice as much rainfall as during some preceding or succeedingyear. This is illustrated by the diagram Fig. 7 of the annual pre-cipitation at Salt La
. Principles of irrigation engineering, arid lands, water supply, storage works, dams, canals, water rights and products. Vv-. Fig. 6.—Map showing mean annual rainfall of the United States. The above map shows in a general way the inequalities of distribu-tion throughout the surface of the country being the averages ofobservations carried on through many years. For any singlelocality there is great divergence; during one year there may occurnearly twice as much rainfall as during some preceding or succeedingyear. This is illustrated by the diagram Fig. 7 of the annual pre-cipitation at Salt Lake City, Utah, where the average is about 16inches, with few years which approximate this amount. Attempts have been made to arrive at some rule or generalizationregarding this irregularity of rainfall; efforts have been made toconnect it with the occurrence of the sun spots and other naturalphenomena. Various students have figured out, to their own satis- 20 PRINCIPLES OF IRRIGATION ENGINEERING faction, that years of drought or flood occur with a certain generalregularity in cycles of 7 years, or 11 years, or 17 years
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectirrigat, bookyear1913
