FLOOD05827

• County: Boulder
• Community: Boulder
• Stream Name: Boulder Creek
• Basin: South Platte
• Title: Boulder Creek Phase B
• Date: 12/1/1979
• Prepared For: Boulder
• Prepared By: UDFCD
• Floodplain - Doc Type: Floodplain Report/Masterplan

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to serve as a setback levee. The improvements would extend from

the mouth of the canyon downstream to 24th Street, the downstream

limit of development in the 1940's.

The reconnaissance investigation, completed in March 1970, indi-

cated that a serious flood potential remains unresolved on Boulder

Creek. In view of these indications, a more detailed feasibility

study was recommended. The feasibil ity study would evaluate the

best means to achieve the most reasonable balance between structural

works, flood plain regulation, and a broad program of flood plain

The plan includes the removal of one bridge, the construction of

two new bridges, and the reconstruction of four bridges; the

replacement of a fixed irrigation diversion structure at Broadway

Street with a collapsible dam; and the removal or relocation of 50

houses and commercial buildings. This plan was designed to pre-

serve the natural beauty of the existing tree-lined channel where

practicable. The overbank areas would be cleared of all major

obstructions and improved as natural parks and recreational areas.

management.

In June 1970, the Office of the Chief of Engineers reclassified the

project to an "active" status. At this time, the Corps of Engineers

Committee on Environmental Planning, Boulder Subcommittee (CECEP)

waS formed to advise the Corps of Engineers on local and environmental

issues concerning the authorized project.

No action was taken on the Boulder Creek Local Protection Project

after authorization due to lack of local interest and support. The

project was placed in an "inactive" status in 1957.

A reformulation of alternatives was the result of a post-authorization

General Design Memorandum started in 1971. More than 50 variations

of structural and nonstructural flood control concepts were evaluated.

Of these, only two, a channel enlargement concept and a levee and

floodwall concept were economically justified. During the reformula-

tion process, the Corps of Engineers contracted for an environmen-

tal impact analysis of the flood control concepts. A report on the

analysis was completed in November 1972 by the Thorne Ecological
Institute of Boulder.

Floods in Boulder and nearby communities and local pressures to

develop the Boulder Creek flood plain prompted the city of Boulder,

in June of 1969, to request the Corps of Engineers to restudy the

Boulder Creek flood control project. Later the same year, the

office of the Chief of Engineers reclassified the project to
"deferred" status, and directed the Omaha District to undertake a

reconnaissance investigation of the authorized project. This

investigation was to demonstrate whether or not the authorized

project appears to be economically justified under current price

conditions and interest rates and whether reformulation and new

Congressional authorization would be required.

In February 1973, the results of the reformulation studies and the
recommended levee and floodwall concept were presented to the City

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