Laserfiche WebLink
<br />A~qiil'."l <br />u......,.... '-J.' \J-.jl <br /> <br />13 <br /> <br />DROUGHT AND ITS RAMIFICATIONS <br /> <br /> <br /> <br />~1 <br />~-"CiA <br />l:~_~'~77 ~. ~ 'l~________ <br /> <br />-5 <br /> <br />April 30, 1977 <br /> <br />A <br /> <br />B <br /> <br />Oct. 29, 1977 <br /> <br />D <br /> <br />c <br /> <br />Above +4 Extreme <br />+3 to +4 Severe <br /> <br />+2 to +3 Moderate <br />-2 to +2 Near normal <br /> <br />EXPLANATION <br />-2 to -3 Moderate drought <br />-3 to -4 Severe drought <br /> <br />National Weather Service, NOAA <br />Below -4 Extreme drought <br />Values indicate departures from normal climate <br /> <br />Figure 7. Maps of the United States showing values of Palmer index on four selected <br />dates in 1977. <br /> <br />undeveloped basin; and others may be made to <br />maintain diversions out of the basin. Also, <br />evaporation losses are increased, and water <br />development projects are not operated at <br />maximum efficiency because of errors in <br />forecasts of precipitation and runoff. And <br />after the stored water has been reduced <br />abnormally, the tendency is to store most of <br />the runoff the next time it occurs to replenish <br />the water released. This in turn may reduce <br />downstream flows below the usual controlled <br />amounts. <br />The above factors can be advantageous to <br />some people and a disadvantage to others at <br />the same time. The usual sequence is that the <br />release of stored water enhances the water <br />supply in the early stages of a drought. But <br />when the carry-over storage is depleted during <br />a multiyear drought, the increased demands <br /> <br />for water that the development stimulated <br />cannot be met, thus causing greater economic <br />losses in the later stages of a prolonged <br />drought. <br />The onset of a drought is usually a subtle <br />process~ertainly not as cataclysmic as other <br />natural disasters such as floods and earth- <br />quakes. There is no first day of drought. <br />People begin to suspect its approach and then <br />suddenly find that it arrived some time ago. <br />However, the effects of a drought can be more <br />widespread, and can cause greater economic <br />and social problems than the more dramatic <br />events. <br />Throughout the 1976-77 drought, there <br />were many people who were not convinced <br />that drought conditions existed. Two exam- <br />ples: Some lived where localized storms <br />produced enough rain at the right time that <br />