FLOOD10385

• County: Jefferson
• Community: Golden, Lakewood
• Stream Name: Upper Lena Gulch
• Basin: South Platte
• Title: Major Drainageway Planning - Upper Lena Gulch - Phase B Report
• Date: 3/1/1994
• Prepared For: UDFCD
• Prepared By: Boyle Engineering Corporation
• Floodplain - Doc Type: Floodplain Report/Masterplan

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The existing structure under the Heritage Square access road is a 60" diameter CMP culvert and has capacity for
approximately the 10-year flow. The access road and Highway 40 will be overtopped during the 100-year event
causing flow to split. Approximately 90 cfs will follow an independent flow path along the southeast side of
Highway 40. Thc SIJUctUIC UUdel Highway 93 is alsu a 60" diamctcI CMP. Buththc 10-yt;"dJ and 100-yt:alfluws
will overtop Highway 93, just upstream from the confluence of Apex Gulch and Lena Gulch. Damages in this reach
are minor since no residential or commercial structures lie in or near the floodplain. The recommended
improvements for this reach include erosion control structures at regular intervals to stabilize the channel. These
structures should improve the downstream water quality and will help to prevent streambed degradation.

Reach L-13

Comments on Sheet 2 of 18

Station 450+00 to 425+00

REACH L-13 (Continued) - SHEET 2
Item Description
Erosion Control Structures
- Includes excavation, b
Total Construction Cost
- 15% Engineering
- 20% Contingencies
TOTAL COST

Ouantitv Unit Unit Price Cost
- ~
190,000
17,900
27.400
164,300

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