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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maintenance level improvements which have been

the

n addition

crossings

Cole Boulevard and Eldridge

'-70

The drainage structures under

year flow.

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from

constructed have helped stabilize the channel eliminating severe damages

and Cole Boulevard downstream are all sized with adequate capacity for

Street;

reach have not significantly

the improvements done in this

al

However,

erosion

Adequate erosion protection has been

overtopping

provided in the channel at most

1 DO-year flows without

the

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residential properties

to

the damage potential

enlarged the channel capacity and

locations

is quite

Y oungfield Street

The concrete box culvert under

relatively high

is sti

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causes a backwater

road embankment

undersized and, because of the high

serve

West

Denver

portion of

the lower

n

three small detention ponds

The

during greater than about the 50-year flood

effect and overtopping of the street

accumulation

Sediment

the development.

from

runoff

to contain local

primarily

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removal

requiring periodic

the ponds is a continuing maintenance concern

n

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11-12

Sheets

+60

191

63+55 to

Sta

L-1

reach are expected to be

Damages In this

owners

West

and disposal by Denver

mostly of debris cleanup and removal

minor and consist

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through single-family

Youngfield Street the channel continues

Downstream of

L-2

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mostly unimproved, although

reach is

this

The channel in

residential property

1 0-11

Sheets

191 +60 to 223+00

Sta.

this

n

own

several property owners have attempted improvements of their

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near

directly in or

several homes lie either

upstream

just

reach, as in Reach L-2

reach

of this

the upstream limit

Pond is

West

Denver

of the lower

The outlet

floodplain is contained between

The

floodplain

100-year

limits of the

the

the

Gulch crosses

Lena

the pond

of

downstream

feet

Approximately 250

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The previous

the drainageway

to

mmediately adjacent

properties which are

the Agricultural

Welch Ditch in Reach L-4

the

Like

rrigation Ditch

Agricultural

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culvert at 20th Avenue was undersized and had a history of flooding problems

The

Ditch crosses over the Lena Gulch channel in a rectangular concrete flume

have

residential properties located just upstream of 20th Avenue on the east

Two

O-year flows without

1

less than the

flume only has capacity for

opening under the

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1992)

(November,

completed

recently

A

damaged

been

repeatedly

flume.

overtopping the

flooding problems

help to alleviate the

structure at 20th Avenue wi

replacement

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were associated with the previous undersized culvert. The enlarged opening

that

the Lena GUlch channel enters a single-

Downstream of the Agricultural Ditch

edge of the

the southeast

floodwall along

the concrete

area combined with

reach only has

this

through

The channel

residential development

family

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20th

upstream of

just

property damage

for

the potential

reduce

drainageway

the drainageway

about the 2-year flow. Several homes adjacent to

capacity for

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Avenue

Past

100-year floodplain

near the edge of the

directly In, or

are located either

7

Alkire Court. and Arbutus Street

those

which previously existed at

Alkire Street,

the constrictions

removal of the culvert crossings at

mostly eliminated

have

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