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_.--- 40 THE ARKANSAS RIVEft ~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 area east of La Junta. It was due to ~ery heavy' rains. Records kept. by the Amity Canal Co. at various points showed a rainfa.Il of 6 inches or more extending from Prowers to Holly. . Practically all the rain was believed to have fallen in eight hours during the night or Octo- ber 18. The area. affected by the flood extended from La Junta on the west to Lamar on the east and from the ,Missouri Pacific Rail- road on the north to the south boundnry of Otero, Bent, and Prowers count.ies on the south. The maximum stage or the river at Holly was 11 reet 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 13G,000 second-reet. The flood at the Amity dam W!IS estima.tedas greater than 100,000 second-reet. 111 That this flood did. not affect the. upper river is shown by the ract that the ma.ximwi1 discharge of the Arkansas at Pueblo ror a week prior to the, flood was only 298 second-feet, which showo$ that there was no flood at Pueblo within the time it would have takim 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 ''\''as that or 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-reet from a. drainage area or 6.1 square miles, or 1,580 second-feet per squa.re mile.1s ' 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 or such discharges has been made. The following table shows the greatest previously recorded unit rUll-offs in the Rocky Mountain States, nrranged in order of unit magnitude: . ;. -,,'1 ' . ~.- I ,. Freeman, W. B.. U. S. Geol. Survey Water,SIIPply Pnper,27t; pp, 33-40, 1910. ,. Data furnished by Denver &I Rio Grande Western Rllllroad Co.