FLOOD00850

• Designation Number: 31
• County: Arapahoe
• Community: Unincorporated Arapahoe County
• Title: Major Drainageway Planning - Little Dry Creek, Report, Volume I
• Date: 2/1/1974
• Designation Date: 6/1/1974
• Floodplain - Doc Type: Floodplain Report/Masterplan

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The principal unit prices used in preparing the preliminary cost estimates
are as follows:

Direct construction costs developed from work quantities and estimated

unit prices were increased by a contingency allowance of 20 percent to

cover uncertainties. Construction costs were then increased by 15 percent

to cover estimated administrative and engineering costs. Right-of-way

costs were estimated, depending on the individual circumstances for each

improvement, and were added to arrive at total estimated project cost for

each of the proposed improvements.

It should be emphasized that the channelization and conduit costs are pre-

dicated on the reduction of the flood flows by the six detention dams. If

the dams are not constructed, the costs given for channelization and conduits

are no longer valid, but would need to be increased to furnish protection

of the lOa-year flood. Conversely, without the dams, the construction repre-

sented by these costs would give less than lOO-year flood frequency protection.

The detention dams are justified because their cost is less than the cost

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Item

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Earthwork

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Dam embankment
Dam structural excavation
Channel shaping for grass-
lined sections
Channel structural excavation
Concrete-lined channel fine
grading
Compacted structural backfill

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Riprap

Dams
Channels

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Other

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Reinforced concrete
Bridges
CuI verts
Underfrains
Seeding and mulching

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Unit

Unit Price - Dollars

cu yd 1.50
cu yd 1.00
cu yd 3.00
cu yd 6.00
sq yd 0.45
cu yd 2.50

cu yd
cu yd

12.00
25.00

cu yd
horiz. sq ft
horiz. sq ft
Un ft
sq yd

l20.00
30.00
25.00
5.00
0.60

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