FLOOD06564

• County: Boulder
• Community: Boulder
• Stream Name: Goose, Wonderland, Elmer's Twomile, 2-mile, 4-mile
• Basin: South Platte
• Title: Major Drainageway Planning Volume 1, Part B
• Date: 4/1/1969
• Prepared For: Boulder County
• Prepared By: CWCB
• Floodplain - Doc Type: Floodplain Report/Masterplan

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Street. Elmer's Twomile drainage basin and storm runoff route is
also urbanized,

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Most of the Wonderland Creek drainage basin and flood route is on
the brink of total urbanization. Fourmile Canyon Creek is still
mostly situated in a rural setting, though development pressures
are great along its channel, About 35 percent of the Fourmile
Canyon Creek waterway east of the hogback is suitable for saving
by effective flood plain zoning. The remainder must be channel ized,

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Sediment yield from Twomile and Fourmile Canyon Creeks is a problem
of significant proportions, The recent cutting of roads and general
impact of development in the Twomile Canyon basin has created a problem
where sediment flows freely into the Juniper-Kalmia neighborhood
of Boulder even during low flow periods, Fourmile Canyon Creek
wil I have similar soil erosion and channel instability problems as
residential development continues, unless proper County regulations
can be brought to bear soon,

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Flooding problems in North Boulder have not been well recorded.
Problems have occurred there, but they have not often been sensa-
tional enough to warrant detailed news coverage, However, some
accounts are presented in the following paragraphs,

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The headl ine on an article in the Boulder Oai ly Camera reads "Two-
Mi Ie Canyon Gully Washer Spews Mud Across Broadway and Into Yards,"
The date waS August 19, 1965. The first paragraph of the article
states, "Water cascading down normally-dry Two-Mile Creek spewed mud
across sections of Broadway and silted yards and basements of 8 or
10 homes near Broadway and Iris Avenue Wednesday afternoon,"

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The drainage basins north of Boulder Creek have contributed heavily
to general floods and at times have been the sole source of inunda-
tions, The Boulder Creek flood of 1894 was the worst yet recorded
in the Boulder area but area-wide floods recurred in 1897, 1906,
1909, 1921, and 1923 to mention just a few of the years when flooding
was widespread, In 1909 two persons were drowned when Twomi1e Canyon
Creek became a torrent as a result of a local cloudburst, Two more
persons were injured seriously enough to require treatment in a
hospital,

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Fourmile Canyon Creek has flooded frequently and on occasion has
caused extensive damage, In 1916 the railroad tracks near Pleasant-
view School were washed out. Again in 1941 a flood in this stream
washed out tracks northeast of Boulder, In the years between, less
noteworthy flooding occurred in this drainageway, but the main reason
damage and loss were not more extensive was that much of the area
was still devoted to such rural uses as grazing,

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Floods in Twomile Canyon Creek have been frequent and at times damage
has been extensive. The worst flood in this basin occurred in 1933 but

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