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<br />of Prowers, the peak discharge was computed as about 70,000 cfs.
<br />
<br />Flood of 1908 . The flood 01 October 19-20, 1908, was caused by heavy rains,
<br />chielly during the night 01 October 18, which covered the part 01 the Arltansas River Basin
<br />in Colorado east 01 a line running just west 01 La Junta, except the area south 01 a line
<br />from the Purgatoire River above Smith Canyon to the southeast comer 01 the State, The
<br />Geological Survey made an investigation of this flood soon alter it occurred,
<br />
<br />Rain gauges were also in operation at various points along the canal, which is part
<br />of the Am~y canal system, north of the Arkansas River, These gauges recorded
<br />precip~ationof 6,25 inches 40 miles northwest of Holly, 6 inches near Prowers, and 6,34
<br />inches a few miles north of Lamar, Most of the rain fell within 8 hours during the night of
<br />October 18-19,1908,
<br />
<br />The flood 01 1908 appears to have had two distinct parts, The first, October 19,
<br />due chiefly to the very heavy rains on the north side of the river. Throughout the area
<br />affected the ground was very hard and dry and had been grazed so closely that practically
<br />no vegetation remained, These cond~ions were conducive to an extremely high
<br />percentage of run-off, and ~ is believed that as much as two-thirds of the 6-inch rainfall
<br />reported appeared immediately in streams, On the north side of the river the water was
<br />reported to have "flowed away in a perfect sheet, overspreading the whole country and
<br />running into the river chiefly below the Amity Dam at Prowers, causing a very rapid rise",
<br />This run-off reached Holly sometimEl before midnight, October 19, and reached a stage
<br />of 9,8 feet on the gage at Holly. The flood was prolonged by the arrival of flood waters
<br />from Two Butte Creek and smaller tributaries from the south, and had only receded haff
<br />a foot the morning of October 20 when the second flood arrived,
<br />
<br />The second part of the flood was caused chiefly by floodwaters from the Purgatoire
<br />River, It reached a peak stage of 11 feet at Holly at noon, October 20, At 7 a,m, October
<br />21 it had receded to 4.6 feet, and at 7 a,m, October 22 ~ was 3,0 feEl!.
<br />
<br />The peak discharge at Amity Dam, haff a mile north of Prowers, was estimated at
<br />more than 100,000 cfs, and at Holly a slope-area measurement made by the Am~y Land
<br />Co, gave a discharge of 136,000 cfs, The discharge at Holly in 1908 was slightly greater
<br />than during the flood of 1921,
<br />
<br />Flood of 1921, Above the mouth of the Purgatoire River no damaging flood
<br />occurred alter 1894 until 1921, when the general storm that covered the State June 2-5
<br />was concentrated in a series of cloudbursts between Canon City and Pueblo, These
<br />covered two separate areas, The larger area, roughly elliptical, extended from the northern
<br />boundary of Pueblo County to the top of the Wet Mountains near Beulah, a distance of 30
<br />miles, and from a point a short distance above the mouth of Rush Creek nearly to Pueblo,
<br />a distance of 15 miles. The smaller area covered the south slope of the Pikes Peak uplift,
<br />Which forms the northern part of the mountain valley, and extended Irom a point above
<br />Skaguay Reservoir to a point 3 or 4 miles south of the river, a distance of 25 miles, and
<br />from Oil Creek to Beaver Creek, a distance of 11 miles. The two areas together comprise
<br />550 square miles,
<br />
<br />Colorado Flood
<br />Hydrology Manual
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<br />4.26
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