FLOOD10386

• County: Jefferson
• Community: Golden, Lakewood
• Stream Name: Upper Lena Gulch
• Basin: South Platte
• Title: FHAD - Upper Lena Gulch
• Date: 1/1/1993
• Prepared For: UDFCD
• Prepared By: Boyle Engineering Corporation
• Floodplain - Doc Type: Floodplain Report/Masterplan

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I

15-16

Sheets

Sta. 0+00 to 29+00

AG

+00 to 40+00: Sheet 13

Sta, 31

P-3

I

split

flow

multi-directional

floodplain in Apex Gulch is complicated by a

The

relatively

is

View Tributary

the Pleasant

reach on

this

through

floodplain

The

I

to Heritage

road

access

the upper

through

the undersized culvert

caused by

quickly

fairly well contained at the upstream limits of the study but

broadens as

narrow and

I

100 cfs leaves the main channel and enters the Heritage

Approximately

Square

the

reach

to

travels overland across undeveloped property

flow

the main channel in a

250 cfs leaves

About

the south

Square development to

reach occur

this

Damages in

upstream of Orchard Street

of residential structures located

just

improved channe

I

the north of the main channel which crosses undeveloped

1500 feet downstream

re-enters the main channel approximately

to

flow path

property and

second

the

damage is also expected in this reach

mmediately adjacent to

imited number

Erosion and minor pavement

to a

floodplain

I

Sta, 0+00 to 31 +00

P-1,2

I

as

the development

through

travels

into Heritage Square

flow split

100 cfs

The

3-14

Sheets

out the main entrance

1 foot,

flow, with average depths less than

mostly shallow

I

the mainstem of

re-enters

flow

The

as sheet flow

the parking lot

and across

floodplain

the

View Tributary have

the Pleasant

n

reaches

two

The lower

I

upstream of

just

U.S. Highway 40 and Highway 93

the vicinity of

Lena GUlch in

in

the point

to

the banks of the improved channel

completely contained within

The split flow option In HEC-2

Apex Gulch with Lena Gulch

the confluence of

tributary

asmal

At this point

terminates

mproved channel

where the

reach P-1

I

the channel in both paths near the

the discharge leaving

was used to compute

flow comes

This

the southwest

from

flow

View

the main Pleasant

flow enters

road to Heritage Square

upper access

n addition

View Subdivision

the Pleasant

from local drainage within

primarily

I

View

the Pleasant

the main channel on Lena Gulch splits and joins with

from

flow

I

the Heritage Square parking

from

the sheet flow

reach

end of this

At the lower

to

this area widens

floodplain In

the

As previously mentioned

flows

Tributary

n addition

flows overtop Highway 93

Gulch channel

main Apex
from

the

and

ot

flow

there

From

West.

undeveloped land on Camp George

an area of

cover

I

the overflows crossing

with

Gulch combine

Lena

overflows

upstream

the

the undeveloped property in Camp George West to

travels overland across

I

flow area

this complicated

surface elevations In

Floodplain water

Highway 93

to minor

reach are primarily due

this

Damages in

erosion and debris cleanup and

confluence with Lena Gulch

the upstream energy of the Lena Gulch and Apex

were computed by balancing

removal

I

Gulch overflows

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8

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