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. - --"-- 40 THE ARKANSAS RIV~ ~OD OF JUNE 3-5, 1921. . The next serious flood in the Arkansas Valley, and the last one' before 1921, occurred October 19-21, 1908, and affected the llrea east of 1:a Junta. It was due. to ve~ heavy rains. Records kept. by the Amity Canal Co. at varIOUS pomts showed a rainfall of 6 inches or more extending from Prowers to Holly. Praetically all the rain was believed to have fallen in eight hours during the night of Octo- ber 18. The area affected by the flood extended from La Junta on the ,,'est to Lamar 011 the east llnd from the Missouri Pacific Rail- road on the north to the south boundary of Otero, Bent, and Prowers counties on the south. The maximum stage of the river at Holly was 11 feet on the river gage. The maximum discharge at this p~int was estimated from cross sections and slope measurements made a~ter the flood as 136,000 second-feet. The flood at the Amity dam W11S estimated as greater than 100,000 second-feet. 15 That this flood did not affect the upper river is shown by the fact that the ma.ximwri discharge of the Arkansas at Pueblo for a week prior to the. flood was only 298 second-feet, which showq that there was no flood at Pueblo within the time it wotild have takEm for flood flow there to reach La Junta by October 19. MAXIMUM DISCHARGES PER SQUARE MILE PREVIOUSLY RECORDED. During the flood of 1921 the tributary streams had maximum dis- charges per square mile that were almost unprecedented in the Rocky Mountain States. The only recorded unit discharge that equaled them was that of Hogan's Gulch near Eden,. Colo., a station on the Denver & Rio Grande Western Railroad between Colorado Springs and Pueblo. Here a cloud-burst on August 7, 1904, caused a flood that was estimated to have a maximum discharge of 9,640 second-feet from a drainage area of 6.1 square miles, or 1,580 second-feet per square mile.16 It is apparent that streams d:.-aining small areas in the foothill region subject to cloud-bursts must have had as high discharges in the past as those that caused the recent flood, but no record of such diseharges has been made. . The following table shows the greatest previously recorded umt run-offs in the Rocky Mountain States, arranged in order of unit magnitude: ~"7 ' . ~-- i "Freeman, W. B.. U. S. Gee!. 8urvey Water-Supply raper,27t, pp. 33-40,1910. 16 Data furnished by Denver & Rio Grande Western Railroad Co.