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<br />DAMES 8 MOORE
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<br />Often, the magnitude of an estimated PME is many times the maximum
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<br />historical flood in the area. Thus, doubt of the validity of a PMF
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<br />is often expressed, yet history is replete with instances when, after
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<br />a seemingly long history of flood records, actual floods have occurred
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<br />that were many times the previous highest flood.
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<br />At Hartford, Connecticut, the Connecticut River flood of
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<br />1938 was 8.6 feet higher than had been experienced in almost 300 years.
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<br />At Louisville, Kentucky, the Ohio River flood of 1937 was 10.4 feet
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<br />higher than it had been in the previous 105 years of record, with the peak
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<br />discharge (i., 100,00,0 cfs) being almost twice the previous record.
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<br />In Western areas, the experiences are even more startling. The
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<br />Pecos River at Comstack, Texas, (drainage areas 35,300 sq. mi.) had a
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<br />maximum flood prior to 1954 of 116,000 cfs, yet in June of that year a
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<br />flood of 948,000 cfs was experienced. Closer to the South Platte Basin,
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<br />the South Eork of the Republican River, at a point just east of the
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<br />Colorado line (drainage area 2580 sq. mi.) had a maximum knmffi. discharge
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<br />prior to 1935 of 750 cfs in 32 years of observation. In June 1935, the
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<br />peak discharge was 150,000 cfs, arising from observed rainfall amounts
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<br />of up to 26 inches.
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<br />Even more important 'have been experiences in the South Platte
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<br />Basin. The folloHing tabulation shoHs maximum observ"d floods prior
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<br />to 1965, comp2xed Hith flood p""ks observed iT'. the 1965 flood (where a
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<br />storm cent-er of 21 inches in 6 hours had occu'rred at Higgins, in the
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<br />heart of the basin): Drainage Years or Flood Peaks, in cfs
<br /> Ar"a Record Prior Prior to
<br /> Station _(~'L: mi.) to 1965 1965 1965
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<br />Plum Creek at LOLlviers 302 23 7,700"'" 154,000
<br />South Platte at Littleton 3,069 25 9,700".\ 110,000
<br />~;ol1th Platte at Ft. ~~()rg~n 11,,1300 30 84,OOo.'.'i 200,000
<br />Kiowa Creek at Kio~<Ja 111 18 110,000' ".l. 19,700
<br />East Bijou Creek at Deer 302 30 25,OOOlll 274,000
<br />Trail
<br />Bijou Creek near Higgins 1,3lL. 30 283,000 ...\. 466,009,'
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