Laserfiche WebLink
<br />I <br /> <br />2888 <br /> <br />..5- <br /> <br />DAM ES 6- MOORE <br /> <br />I <br /> <br />Often, the magnitude of an estimated PMF is many times the maximum <br /> <br /> <br />historical flood in the area. Thus, doubt of the validity of a PMF <br /> <br />, , <br />is often expressed, yet history is replete with instances when, after <br /> <br /> <br />a seemingly long history of flood records, actual floods have occurred <br /> <br /> <br />that were many times the previous highest flood. <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />At Hartford, Connecticut, the Connecticut River flood of <br /> <br /> <br />~938 was 8.6 feet higher than had been experienced in almost 300 years. <br /> <br /> <br />At Louisville, Kentucky, the Ohio River flood of 1937 was 10.4 feet <br /> <br /> <br />higher than :it had been in the previous 105 years of record, with the peak <br /> <br /> <br />discharge (4,100,000 ds) being almost twice the previous record. <br /> <br />I <br /> <br />I <br /> <br />In Western areas, the experiences are even more startling, The <br /> <br /> <br />Pecos River at Comstock, Texas, (drainage areas 35,300 sq. mi.) had a <br /> <br /> <br />maximum flood prior to 1954 of ,116,000 ds, yet in June of ,that year a, <br /> <br /> <br />flood of 948,000 cfs was experienced. Closer to the South Platte Basin, <br /> <br /> <br />the South Fork of the Republican 'River, at a'~point justesst of the <br /> <br /> <br />Colorado line (drainage area 2580 sq. mi.) had a maximum known discharge <br /> <br /> <br />prior to 1935 of 750 ds in 32 years of observation. In June 1935" the <br /> <br /> <br />peak discharge was 150,000 cfs, arising from observed rainfall amounts <br /> <br /> <br />of up to 26 inches. <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />Even more important have been experiences in the South Platte <br /> <br /> <br />Basin. The follo<"ing tabulat:ion shows maximum observed floods prior <br /> <br /> <br />to 1965, compared wi.th flood peaks observed in the 1965, flood (where a <br /> <br /> <br />storm center of 21 inches in 6 hours had occurred at Wiggins, in the <br /> <br />I <br /> <br />I <br /> <br />heart of the basin): Drainage Years of Flood Peaks, 1Il cfs <br /> --- <br /> Area Record Pri-or- Prior to' <br /> Station ~,-_mi,,l ,~_l965 __ 1965 1965 <br />Plum Creek at Louviers 302 23 7,700 154,000 <br />South Platte at Litt'leton 3,069 25 9,700 110,000 <br />South Platte at Ft. Morga-n 14,800 30 84,000 200,000 <br />Kiowa Creek at Kiowa 111 18 110,000 19,700 <br />East Bijou Creek at Deer 302 30 25,000 274,000 <br />Trail <br />Bij ou Creek near Higgins 1,314 30 283,000 466,000 <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br /> <br />I <br />