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40 /1>""" 1050 1000 HYDROLOGIC AND HUMAN ASPECTS OF THE 1976-77 DROUGHT ,,' 95' 90' MISSOURI I COLORADO I KANSAS ---------,--~----------------- i--------i I I /' I OKLAHOMA Tucumcari I oOklahoma City o I I I '<eo 34' EXPLANATION --- Region boundary o '00 I 200 KILOMETERS I I 100 MILES Figure 15. Arkansas-White-Red-WRC Region 11. o total monthly amounts of precipitation in Kansas and Missouri were small, less than 3 in. April precipitation was weil above normal over most of the region, but May, June, and July rainfall was less than 50 percent of normal near the Colorado-Kansas State line and in the Oklahoma and Texas panhandles. The less than 50 percent of norml;ll area centered around the Kansas-Oklahoma State line in August 1976 and shifted to Missouri in September. Precipi- tation in October was quite varied, but that in November and December was less than 25 percent of normal over major parts of the region and less than 50 percent of normal over almost all of it. Deficiencies of precipitation in the Rocky Mountains of Colorado and in and adjacent to southwestern Kansas continued through March 1977. Large parts of the region had above normal rainfall April through JUly, but small areas below 50 percent of normal precipitation persisted in Oklahoma, Colorado, near the Oklahoma panhandle, and in Missouri. August precipitation was above normal everywhere except in New Mexico and Arkansas. The August precipitation in Missouri was sufficient to provide adequate soil moisture and lessen the threat of a severe drought during the late summer and fall. Rains in eastern Kansas during the same period diminished the severity of the drought there. September and October were generally dry and a wet period returned in November 1977. Monthly flows in the Arkansas River at Canon City, about 35 mi west of Pueblo, Colo., dropped into the lowest 25 percent of the monthly flows in December 1976 and stayed that low for 17 months. The first half of this recession was caused by the low runoff from the much below normal snowpack in the Rocky Mountains, and the rest by that plus the in- creased diversions for irrigation. All time monthly low flows since records started 89 years ago occurred in May and August 1977. At Dodge City, 50 mi east of Garden City, Kans., the Arkansas River was dry for 212 days from September 21, 1976 to April 20, 1977, the longest period of no flow on record. Intermit- J