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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of the importance and functioning of these two drainage systems. The
function of the initial system is to handle runoff so that it will
eliminate inconvenience. Beyond this, however, the major system ful-
fills the main damage-prevention function. The major system wil I ope-
rate whether or not it has been designed and whether or not urban im-
provements are situated wisely in regard to it. In nearly all cases
it is economically impossible to provide an initial drainage system of
sufficient capacity to obviate the need for the major drainage system.

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The work in this assignment deals exclusively with the major drainage
system. The study did not include a review of the initial drainage
system. Once the major drainage system is planned, designed and con-
structed, the initial drainage system consisting of storm sewers and
small channels falls into order more easily. The future cost of storm
sewer works in North Boulder will be only a small fraction of the
amount that would be spent without a good major drainage system. In
many places storm sewers will be unnecessary because of the existence
of the major drainage works. It should be kept in mind that any money
spent on major drainage will be more than saved in the future because
of the savings on the, storm sewer systems.

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ALTERNATES STUDIED

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The alternates which were studied and reviewed in detail by the envi-
ronmental design team included the following:

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FOURMILE CANYON

lA, Fourmile Canyon Existing Channel,
IB, Fourmile Canyon Diversion to Sixmile Reservoir,

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IIAI,
IIA2,

Wonderland Lake Channel to Sewage Plant,
Wonderland Lake Channel to Sewage Plant with Diversion
of Upper Basin to Fourmile Canyon at 19th Street.
Wonderland Lake Channel via 30th Street to Goose Creek,
Wonderland Lake Channel via 30th Street to Goose Creek
with Diversion of Upper Basin to Fourmile Canyon at
19th Street.

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I I. WONDERLAND LAKE CHANNEL

IIBI.
II B2,

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I I lA, Twomlle Canyon to Goose Creek via Public Service Company
right-of-way.
IIIC. Twom 11 e Canyon to Goose Creek via I r i s Avenue,
III D. Twomile Canyon to Goose Creek via I r i s Avenue and
Columbine School,
IIIE, Twomlle Canyon to Goose Creek via Grape Street and
Columbine School,
I I lAG, Twomlle Canyon to Goose Creek via Public Service Company
Right-of-Way with Diversion of Twomile Canyon at Hogbac k
to Won de r 1 and Lake,

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I I I. TWOMILE CANYON

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