FLOOD00898

• County: Statewide
• Title: Floods in Colorado
• Date: 6/1/1948
• Prepared For: State of Colorado
• Prepared By: USGS
• Floodplain - Doc Type: Flood Documentation Report

.

.

~ 10

FLOODS IN COLORADO

METEOROLOGIC CONDITIONS

11

The high-water slopes on both banks throngh the reach of river
selected are measured,and the average of the two is taken s.s the slope
during, the flood peak. Cross sections of the channel to the high_
water line are run at each end of the reach, and if the reach is long, a
cross section between the two end sections is also run; the average of
the cross sections_is used to compute the discharge by the Chezy
formula, V =C-vRS. The coefficients of roughness used in the com-
putations are bllSed both on judgment and on experiments made to
determine them. If there is considerable difference in the arellS of the
upstream and downstream cross sections, it is necessary to consider
the velocity head and to correct the slope of the water surface to the
energy gradient.

METEOROLOGIC CONDITIONS CAUSING MAJOR FLOODS

Meteorologic conditions preceding the floods of the late spring of
1844, and of June 1864, May 1876, June 1884, May 30, 1894, and
June 1921, the IllSt named of which was the most widespread on record
are set forth in this report, as are also those of frequent occurrence that
produced the floods of September 1909 and Octobcr 1911, which
affected more than one large drainage area. Precipitation records
of floods in anyone basin are presented in connection with the descrip-
tion of those floods.
IB44

The belief that floods were widespread during the spring of 1844
as a result of heavy rains falling on a deep snow cover rests chiefly
on circumstantial evidence. Settlers came to Pueblo and the upper
Arkanss.s Valley in 1859, and reports were common among them
concerning an Indian legend of a flood in which the water "reached
from bluff to bluff"-an expression commonly used in connection
with legends about floods on western rivers. This circumstantial
evidence WllS reinforced by the statement of Rockafellow,' in his
history of Fremont County, that a French trader named :Maurice,
who lived near the mouth of Adobe Creek, told the pioneers that 4
feet of snow fell all over the valley in 1844 and lay there three "moons,"
from all of which it is surmised that the flood of Indian legend was.
in 1844, the year of the great flood at St. Louis. In that year the
lower Arkansas River at Little Rock reached a stage of 32.6 feet, as
compared with 34.6 feet in 1833, and 33.0 feet in 1927.' Furthermore,
a high-water mark of this flood at Pueblo was reputedly 12 feet higher
than the high-water mark of the flood of 1921, the greatest flood of
record there,'

The evidence of a flood in the South Platte River BllSin the same
year rests on the diaries of Clyman,' who left Independence Mo.,
on May 14, 1844, on his way to Oregon. He records almost daily
rains and floods from that time until July 10, when the party crossed
the Divide from the Kansas River to the Platte River near the present
site of Grand Island, Nebr, The latter stream WllS "as high or higher
than the Knnsas," which he had previously described llS being very
high. The KansllS River had its highest flood of record during the
spring of 1844, the stage at Topeka being about 2 feet higher than that
reached in 1903.' More specific data regarding the flood in the South
Platte River BllSin is contained in a letter written by Antoine Janis,
a French trapper on the Cache la Poudre River near thc present site
of Laporte. Ansel Watrous,' an early historian of Larimer County,
quotesJrom this lctter as follows:
On the first da.y of June 1844, I stuck my stake on a olaim in the valley.
. * * At tha.t time the streams were all very high.

Further data, also indirect in character, .refcr to a great flood in
the vicinity of Denver. Albert B. Sanford, curator of the State
Historical Society Museum, in an article in the Colorado Magazine,
May 1927, qUQtes a statement made in 1864 by the editor of the
Rocky Mountain News:
Mr. Byers told the writer of an old Indian who * * * solemnly warned of
"heap big water" such as he had seen cover the whole bottom lands "so," and he
held his hands above his head.
In further confirmation of the flood of Indian legend, an unsigned
articlc in the Denver Commonwealth, June 22, 1864, reads in part:
In the summer of 1861 we ware one of I..ieut. Berthoud's exploring part.y to and
from Salt Lake City. Major James Bridger, one of the most thorough practical
explorers in the West, was guide on that trip. * * * He proceeded to t.ell
us that many years ago while on a journey from Fort Laramie to some other
point, he found the entire bottoms of Cherry Creek anq. [South] Platte River
covered between the extreme bluffs of the two, which compelled him to remain on
the opposite bank from [the present site of] this city 9 days before he was able to
effect a crossing.
As the article quoted described Bridge.. as an old man in 1861, he
would have been active in 1844, and as no other reference is known
concerning a great flood in the South Platte River Basin prior to 1844,
it is believed Bridger's reference was to the flood of that year,
The referenccs to deep snow in the Arkansas River Valley and to
continuous rain in the Platte River Basin lcad to the conclusion that

. James Clyman's diaries and memoranda of a journey through the far Wcst, 1844 to 1846, Book I. Call.
fornia Rist. Soc., 1928.
. Kansas River, Colo., Nebr., and Kans.: ?ad Cong., 2d sess., H. Doc. 195, pp. 38-39, 1934.
7 Watrous, Ansel, History of Larimer County, Conner Printing & Publishing Co., Fort Collina, Colo.,
IOU,

. RocbfeUow, B. F.p Hlstory of Arkansas Valley, O. L. Baskin & Co., Cblcsgo, 188!.
. Arkansas RIver IUld tributarIes: 74th QOng., 1st sass., H. Doc. 308, vol. I, p. 56, 1936.
, Follansbee, Robert,lUld lones, E. E., The Arkans88 RIver flood of lone 3-5, 1921: U. B. Geological Burve.,
WateNJupply Paper C87. pp. 3&-36, 1922. .