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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the upstream

total energy at

the

was computed by balancing

two paths

the

Sheets 4-5

+50 to 385+00

Sta. 371

L-9

the main channel was computed to be approximately

flow down

The

section

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300 cfs

The concrete-lined

mproved channel section

reach consists entirely of an

This

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reach

this

n

100-year flow.

for the

channel has adequate capacity

rectangular

Sheets 5-7

Sta. 325 + 50 to 353 + 00

L-7

imits except

the channel

with

mits are predominantly coincident

floodplain

the

I

the channel

Here

6th Avenue

the culvert under

an area near the Inlet to

for

mostly undeveloped open space with a

reach covers

this

floodplain In

The

flow and some localized

the

fully contain

height to

sufficient

of

walls are not

I

the edge of the

residential properties located on

low density

of

imited number

the

no structures are located in

floodplain at this location and no significant damages are expected

However,

overbank ponding could be expected

I.

reach is deep and well incised and shows

this

The main channel in

floodplain

reach contains

The upstream portion of this

erosion damage

past

evidence of

I

the split flow as described above for the previous reach

Sheet 5

+50

Sta. 353 + 00 to 371

L-8

I

reach is undersized

Orion Street at the downstream end of this

The culvert under

its historic path and has been

from

relocated

reach has been

this

The channel in

I

a length of

for

roadway

the

to back up and overtop

water

and causes

The

of the Mountain Side Mobile Estates

heavily encroached by development

two

into

to split

flow

the

This overtopping causes

feet.

approximately 600

the

The culvert under

exists has inadequate capacity

now

it

channel as

I

The split flow is described below

separate hydraulically disconnected flow paths

driveway to Mountain Side is also undersized causing overtopping Into the trailer

to erosion and

reach are primarily due

this

Damages in

reach

the next

n

of the mobile

relatively wide, covering most

reach is

this

The floodplain in

park

I

overtopping with some damages to structures and contents expected

pavement

floodplain

the

structures located in

of

Because of the large number

this reach is high

the damage potential in

home park

I

aswel

I

Sta. 312 + 00 to 325 + 50: Sheet 7

L-6

s characterized by a split flow around an

reach

The downstream end of this

flow is

This

Vernon Road

of the main channel along Mt.

the southeast

sland to

I

flow is divided

the

South Golden Road

and upstream of

Below Orion Street

sections

Downstream and upstream

divided and hydraulically disconnected

flow is combined

the

Downstream and upstream sections were identified where

the balancing

flow combined, and the analysis included

were identified where the

the energy

for

flow of 900 cfs

to balance

resulted in a computed

The same procedure as described previously was used

This analysis

flow paths

along both

15

of

flow distribution between

range

a

for

Energy profiles

The

flow path

paths

discharges were computed along each

flow

energy losses along both

of

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