The Drought of 1930

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Precipitation and run-off records indicate that droughts of major proportions, both in severity and in extent, have occurred at intervals of 15 to 20 years and that droughts of equal severity but of less extent have occurred at intervals of 3 to 6 years. The drought of 1930 was a major drought, in which some of the outstanding features were as follows: 1. The year 1930 began with water conditions in most States about normal. 2. The area affected and the deficiency of annual precipitation over this area were slightly greater than in any previously recorded major drought. Neither of these conditions, however, was materially worse than for the major droughts of 1894 and 1910. 3. In most of the areas affected the duration of the drought was much longer than that of any previous one. 4. The minimum annual precipitation records were broken in 18 States, and the monthly precipitation in many localities was below normal for 8 to 14 consecutive months. 5. In many of the areas affected the annual stream flow during the water year ending September 30, 1930, did not fall below previously established minima, and but few records of minimum daily flow were broken. On the other hand, for many streams the monthly flow and the annual flow on the basis of the calendar year reached new minima and for most streams all records of long-continued low flows were broken. 6. Ground-water levels were rapidly reduced to a point below which they did not fall appreciably and the later fall was very slow, indicating that the available ground-water supply for most river drainage basins is so great that it is adequate to maintain the stream This content downloaded from 157.55.39.104 on Thu, 01 Dec 2016 05:55:14 UTC All use subject to http://about.jstor.org/terms 1824 JOHN C. HOYT [j. A. W. W. A. flow at practically a fixed minimum without appreciable change for a considerable period of time and probably through any drought that may be expected. 7. Normal activities, both economic and social, were probably interfered with to a greater extent than during any previous drought, and the resulting losses were greater. The effects of previous droughts related primarily to economic and social activities The effects of the drought of 1930 were also an important factor in political activities. The drought emphasized the following needs: 1. The collection in more detail of the hydrologie data required in wise planning and use of our water resources. This should include a country-wide research into the quality and quantity of both surface and ground water supplies, and also the collection of information leading to the best methods of conservation of supplies for their highest ultimate use. 2. More adequate works for storage of both surface and ground water supplies. 3. More care in planning, so that development will be kept within the limits of available water supplies. 4. More adequate facilities for the disposal of sewage and industrial wastes, in the interests of health and social betterment. 5. More systematic planning and operation of agriculture, to the end that all farms shall produce food crops as well as money crops, in order that adequate food supplies will be insured during years when returns for money crops are small. In the studies leading to this report the following observations were made: 1. That a knowledge of the occurrence of ground water is essential in surface-water studies. 2. That the effects of vegetation are important factors in the consideration of water supplies during the growing period. 3. That precipitation data must be used with great caution in water-supply studies and that there is practically no relation between precipitation and low-water flows. 4. That conclusions drawn from precipitation or stream-flow data expressed as percentages of the mean may lead to erroneous conclusions. 5. That conditions in different drainage basins are so varying that estimates of low flow, based on comparison with adjacent areas or on precipitation data, can not be made with any degree of certainty. This content downloaded from 157.55.39.104 on Thu, 01 Dec 2016 05:55:14 UTC All use subject to http://about.jstor.org/terms VOL. 23, NO. Il] DROUGHT OF 193