FLOOD03506

• County: Jefferson
• Community: Lakewood
• Stream Name: South Lakewood Gulch
• Basin: South Platte
• Title: Major Drainageway Planning
• Date: 8/1/1978
• Prepared For: Lakewood
• Prepared By: UDFCD
• Contract/PO #: &&
• Floodplain - Doc Type: Floodplain Report/Masterplan

COMMENTARY ON SHEET 5

ESTIMATEO CONSTRUCTION COST

A new 6-foot by 4-foot reinforced concrete box would be constructed parallel

to the existing 48-inch concrete pipe outlet from the pond at First Avenue

near Balsam Street across First Avenue to Allison Street (extended). The

existing 48-inch pipe changes size along this stretch. The 31-inch by

51-inch CMP arch pipe would be removed and replaced with a new 48-inch RCP.

Item

Headwall for existing Vance Street 84" RCP

Clean, Fine Grade and Seed Existing Channel
Sta. 49+00 to 52+50

Reinforced Concrete Pipe (RCP) at Wadsworth

A grass-lined channel would closely follow the existing channel route from

the discharge point of the new conduit to the retaining wall upstream of

Wadsworth. A flow separation structure is required at the Rocky Mountain

Oitch crossing. This structure allows gulch flows to be carried over the

ditch while limiting the ditch to its decreed flow capacity. Storm waters

in the ditch that are in excess of the decreed ditch capacity would be forced

to dump into South lakewood Gulch.

Grass lined channel - Wadsworth to 1st Avenue

2 Drop Structures
8' x 4' Reinforced Concrete Box (RCB)

Rocky Mountain Ditch Flow Separation Structure

Extend Existing 48" RCP and add 8' x 4' RCB

Utility Relo~ation

A 96-inch RCP inlet would replace the existing 48-inch pipe at the retain-
ing wall. The 96-inch RCP would transition to an 84-inch RCP at the Wads-
worth crossings and would continue beneath the auto complex, a distance of
approximately 1,500 feet. The construction of this conduit would alleviate
the flooding of Wadsworth Boulevard during a 100-year event to allow it to
be used for emergency traffic.

Clean-up

TOTAL CONSTRUCTION COSTS

Engineering and Contingencies (25% Construction Costs)
Fiscal, legal, and Administrative (8% of Total Above)

A 100-year channel exists at the discharge point of the proposed 84-inch

RCP to Vance Street. It is necessary, however, to clean, fine grade and

seed the channel and to provide an energy dissipation structure at the

pipe outlet.

land Acquisition Costs

TOTAL COST

Annual Maintenance Cost

A new headwall will be added to the culvert at Vance Street in order to
maximize its hydraulic capacity and to protect pipe ends from scour damage.

The 100-year floodplain is to be regulated and it is recommended that the
resDents within and adjacent to the 100-year floodplain be notified
annually of the potential flood hazards.

Cost
$ 8,000
$ 4,000
$242,000
$ 24,000
$ 14,000
$ 4,000
$ 8,000
$ 5~,OOO
$ 14,000
$ 5,000
$294,000

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$ 96,000
$ 39,000
$ 39,000

$548,000

$ 1,000