FLOOD06450

• Designation Number: 92
• County: Jefferson
• Community: Arvada
• Stream Name: Ralston, Leyden Creeks
• Basin: South Platte
• Title: Major Drainageway Planning - Ralston/Leyden Creek, Arvada, Jefferson County, CO
• Date: 8/1/1977
• Designation Date: 1/1/1978
• Floodplain - Doc Type: Floodplain Report/Masterplan

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TABLE 1-1

STRUCTURES TO BE REMOVED .FROM HIGH
HAZARDOUS FLOODWAY

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Phase A
Reach

Structures Required to be Removed
Houses Garages Out-Buildings Mobile Homes

Reach
Description

RALSTON CREEK

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R-1 Clear Creek to
Pierce Street
R-2 Pierce Street to
Garrison Street 14 5
R-3 Garrison Street to
Leyden Confluence 45 5
R-4 Leyden Confluence to
Xenon S tree t 0 0
R-5 Xenon Street to
State Highway 93 0 0
LEYDEN CREEK
L-1 Confluence to
74th Avenue 0 0
L-2 74 th Avenue to
Alkire Street 0 0
L-3 Alkire Street to
State Highway 93 0 0

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6

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Unless otherwise noted, all master plan improvements are to be sized for the
lOa-year event with future basin development, The master plan improvements
include:

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RALSTON CREEK

1. A grass-lined channel from Clear Creek to West 56th Avenue.

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A European type channel from Grandview Avenue to above Pierce
Street. A European type channel is used on this reach of channel
due to the constraint of the extension of Ralston Road from Lamar
Street to Sheridan Boulevard,

2.

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3.

A grass-I ined channel from above Pierce Street to below State
Highway 121. The existing grass-lined channel will not require
modification in this reach, however, the apartment building owners
are encouraged to flood proof and obtain flood insurance.

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54

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7.

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10.

11.

1-2

4.

A European type channel from below State Highway 121 to 600 feet
above Wadsworth Boulevard. A total of seven residences and seven
separate garages will be removed in order to build this channel.

5,

Other than improvements to street crossings, no channel improvements
from 600 feet above Wadsworth Boulevard to below Garrison Street.
The homeowners left in the lOa-year flood plain are encouraged to
obtain flood insurance and to flood proof their dwellings.

6.

A short length of European type channel and a length of grass-
lined channel both sized for the 5-year event from below Garrison
to below Brooks Drive. Certain damages will occur on these
channels from lOa-year flows; however, these damages are unavoid-
able if the discharge is to flow through the constriction formed
by the inappropriate urbanization of the area, The homeowners
left in the lOa-year flood plain are encouraged to obtain flood
insurance and to flood proof their dwellings.

A European type channel from below Brooks Drive to above Lee
Street. A total of 44 residences and 3 separate garages will
be removed in order to bui Id this channel.

A grass-lined channel from above Lee Street to Nelson Street and
no improvements from Nelson Street to below Oak Street, The
homeowners left in the lOa-year flood plain above Nelson Street
are encouraged to obtain flood insurance and to flood proof their
dwell ings.

A grass-lined channel from below Oak Street which transitions to
a European channel below 68th Avenue. There are no improvements
from above 68th Avenue to Simms Street in the existing park area.
One residence will have to be removed to.build the European type
channel. Some damages will be sustained adjacent to these channels
from the lOa-year discharge.

A grass-lined channel from Simms Street to Xenon Street,

A nonstructural (modified) channel from Xenon Street to State
Highway 93, Rock side channel spillways will be located on the
east banks of the Croke Canal and the Farmers Highline Canal.