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Robert Peccia & Associates.

Environmental assessment and nationwide section 4(f) evaluation Canyon Ferry Road : STPS 430-1(5)1; CN 4480, Lewis and Clark County, Montana (Volume 2003) online

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amourits of agriculture
property south of Canyon
Ferry Road. Cut and fiii
heights associated with this
aiternate wouid increase
right-of-way needs over
Alternates 1 and 3.


New right-of-way needed
throughout project.
This alternative would
require the acquisition of
more agricultural land from
more property owners than
Alternate 1 .


New right-of-way needed
throughout project.

Cuts and fills associated
with the new highway would
encroach on several other
residences.

This alternative would also
require the acquisition of
more agricultural land than
Alternates 1 or 3.


Relocation Impacts


With the inciusion of a turn
iane. this aiternate wouid
most iikeiy require the
acquisition of two houses, a
mobile home, a business.
and the 'tront-yards" of three
or more residences near the
intersection.


This alignment would likely
require the acquisition of
one residence just north of
the proposed intersection to
accommodate a westbound
deceleration/right turn lane
and a left turn lane for
northbound traffic on
Spokane Creek Road.
Traffic would be shifted
away from a business
located near the present
intersection.


This alternate would require
the relocation of four
residences and possibly one
mobile home located
adjacent to the existing
highway.


This alternative would
require the total acquisition
of at ieast three residences,
a mobile home, and
potentially a business.


Utilities Impacts


Impacts the greatest amount
of pubiic service utilities that
exist in the present roadway
corridor.


Impacts utilities only at the
proposed intersection.


impactsfewerutiiities than Alternate 1.



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Canyon Ferry Road; STPS 430-1 (5) 1



Environmental Assessment



TABLE 5 (page 2 Of 7)





Alternate Intersection Configurations


Alternate 1


Alternate 2


Alternate 3

"Preferred Action"


Alternate 4


Effects to Helena Valley
Canal Bridge


The irrigation canai bridge
wouid have to be repiaced
because the structure wouid
be incompatibie with the
new design.


The irrigation canai bridge
couid remain as is because
the Spol<ane Creek Road
wouid remain as the through
route.


The irrigation canai bridge wouid have to be repiaced
because the structure wouid be incompatible with the new
design.


Horizontal Alignment


The proposed horizontai
alignment wouid siightly
improve but perpetuate the
curves on Canyon Ferry
Road near the intersection.
Spokane Creel< road would
intersect Canyon Ferry Road
west of the Giass Slipper.


The proposed aiignment
wouid eiiminate three short
horizontai curves associated
with the existing road.

This aiternate would
perpetuate the existing
horizontai curve and limited
sight distance on Spoltane
Creek Road.


This aiternate wouid replace
sharp horizontai curves with
one flatter horizontai curve
and a tangent (straight)
section.


This aiternate has just one
large radius horizontai curve
that replaces multiple curves
on the existing aiignment.
This aiignment wouid offset
Canyon Ferry Road the
furthest from the present
highway.


Vertical Alignment


The verticai alignment wouid
be iessened in thiis area
also, however it wouid stiil
be the maximum design
gradient of 7%.

This option wouid provide
the steepest grade on
Canyon Ferry Road of aii
alternates considered. The
steeper grade was
incorporated to better fit the
terrain and iimit cut and fiii
heights and reiocations.


The steep grade on the
Canyon Ferry Road
approach to the intersection
wouid be flattened
significantly (3.5% vs. 10%
existing grade) by relocating
the intersection to the south.

This alternative alignment's
drawbacks include
substantial cuts and fills to
provide desirable grades
that would change the
existing landscape
significantly. With these
large fills the local approach
access points will also have
steep grades.


The grade on Canyon Ferry
Road for through traffic
would be reduced from 10%
(existing) to about 4%.


The grade on the west
approach would be reduced
from 1 0% (existing) to about
4%.

The verticai aiignment would
result in deeper fills and cuts
as compared to Alternates 1
and 3.

The proposed aiignment
wouid likely not fit the terrain
as well as Alternates 1 and
3.



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Canyon Ferry Road; STPS 430-1 (5) 1



Environmental Assessment



TABLE 5 (page 3 Of 7)





Alternate Intersection Configurations


Alternate 1


Alternate 2


Alternate 3

"Preferred Action"


Alternate 4


Intersection Geometries


Spokane Creek Road would
tie into the Canyon Ferry
Road in a T-intersection
west of the Glass Slipper.
This is consistent with the
proposal that would no
longer require east-west
traffic to stop at the
intersection.

The intersection would be
situated on a substantially
banked curve.


This alternate would
maintain Canyon Ferry Road
as stop-controDed at the
intersection with Spokane
Creek Road. This would be
inconsistent with the
principal traffic flow patterns
observed at the intersection.

The intersection would be
situated on a substantially
banked curve and require a
deceleration/right turn lane.
The intersection would be
undesirably located at the
south end of a long curve on
Spokane Creek Road.


The Spokane Creek Road
intersection would be
reconfigured Into the
preferable stop-controlled T-
intersection.

The Spokane Creek Road
intersection would generally
lie on a flatter grade and be
located within a straight
section of roadway.


This alternate would provide
the preferred treatment of
reconstructing the Spokane
Creek Road as the stop-
controlled leg of the
intersection with Canyon
Ferry Road.


Other Intersections and
Approaches


Residential approaches and
the intersection at Keir Lane
would intersect Canyon
Ferry Road within a steeply
banked horizontal curve.

Properties lying within Ihe
existing Spokane Creek
Road curve area would likely
have steeper approaches
onto either Canyon Ferry
Road, or Spokane Creek
Road due to alignment and
grade of the new roadway.

Approaches to residences
west of the bridge would not
be compatible with the new
road's grade.


The T-intersec1ion with
Spokane Creek Road lies on
a fairly sharp and highly
banked curve. This is an
adverse condition to
negotiate for the vehicles
turning in either right or left
onto Canyon Ferry Road.
These conditions would be
perpetuated with Alternate 2.


The Keir Lane T-iniersec1ion
with Canyon Ferry Road
would lie on curve with
flatter banking as compared
with existing conditions.

Multiple approaches can be
combined allowing for the
elimination of several access
points. Better access
management can be
achieved with this alternate.


The Keir Lane T-intersection
with Canyon Ferry Road
would lie on a normal crown
section. The access
management opportunities
increase with this alternate
as compared to Alternate 1.
Approaches can be more
easily combined and grades
improved as the alignment
shifts further away from
properties that are otherwise
not directly impacted. This
alignment has the furthest
offset from the present
highway, as compared to all
other alternates presented.



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Canyon Ferry Road; STPS 430-1 (5) 1



Environmental Assessment



TABLE 5 (page 4 Of 7)





Alternate Intersection Configurations


Alternate 1


Alternate 2


Alternate 3

"Preferred Action"


Alternate 4


Impacts to Agricultural
Land


Impacts to agricultural land uses associated with all alternates would Include the acquisition of varying amounts of cropland
and pasture land for new highway right-of-way and modifications to field access locations. Generally, access to farm fields
or pastures from the new roadway would be maintained, although) the location of access points maybe moved to ensure
adequate sight distance along the new road. Alternate 1 was judged to have the least impacts to such lands and Alternates
2 and 4 would affect the most agricultural land due to the more extensive realignments.


Impacts to Important
Farmland


This alternative would have
the least impact to important
farmland because the
proposed alignment would
closely follow that of the
existing highway.


There are few discernable differences in impacts between these alternates.


Air Quality Impacts


Air quality impacts are not a project concern due to relatively low traffic volumes and the high existing air quality of the
project area. No discernable difference between alternates.


Water Quality Impacts


Reconstructing Canyon
Ferry Road with this
alternate would require new
crossings of No Name
Spring Creek and Spokane
Creek near the location of
existing crossings. Fill
placement and minor work
within stream channels
would be required at the
new highway crossings.

Alternate 1 would be similar
to Alternate 3 in its impacts
to No Name and Spokane
Creeks.


Reconstructing Canyon Ferry Road under any of these alternates would require new
crossings of No Name Spring Creek and Spokane Creek, the same streams crossed by the
existing highway. Fill placement and minor work vwthin stream channels would be required
at the new highway crossings. Consequently, the impacts of constructing the highway on a
new route through this area would be similar to those associated with rebuilding on or near
the existing highway.


Bridges may need to be
used at stream crossings
because of the fill heights
and the undesirable angles
at which the new road would
cross the streams.


Crossings of both creeks are
close to existing crossings
with similar grades. The
road's "footprint" at the
stream crossings would be
minimized with Alternate 3.


Alternate 4 would result in
substantial fill heights and
require wider fill sections.
This may dictate the use of
longer culverts or potentially
replacing culverts with
bridges at stream crossings.


Impacts to Wetlands


This reconstruction alternate
would impact about 0.13 ha
(0.3acres) of delineated
wetlands.


Alternate 2 would impact
about 0.60 ha (1.5acres) of
delineated wetlands.


This reconstruction alternate
would impact about 0.10 ha
(0.25 acres) of delineated
wetlands.


Alternate 4 would impact
about 0.24 ha (O.Sacres) of
delineated wetlands.



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Canyon Ferry Road; STPS 430-1 (5) 1



Environmental Assessment



TABLE 5 (page 5 Of 7)





Alternate Intersection Configurations


Alternate 1


Alternate 2


Alternate 3

"Preferred Action"


Alternate 4


Vegetation Impacts


This alternate would require
the least amount of clearing
due to the proximity to the
existing highway.


This realignment option
represents a notable
departure from the location
of the existing highway and
It would require that
vegetation be permanently
cleared to establish the new
alignment. The proposed
realignment would require
more clearing than any other
alternate due to Its
substantially higher fills
through the Spokane Creek
drainage and deep cuts
through the hill s to the west.

This loss of vegetation
would be offset In part by
obliterating the old section of
Canyon Ferry Road and
reseeding the former right-
of-way.


This alternate would require
more clearing than Alternate
1 but less than Alternates 2
or 4.


The affects to vegetation
would be similar to those
associated with Alternate 2
due to Its large cut and fill
sections.


Wildlife Impacts


Highway reconstruction on
or near the existing
alignment would result In the
permanent loss of minor
amounts of habitat and
temporarily displace some
species.


The road widening and slope modifications associated with the rebuilding on these offsets
alignment would result In the permanent loss of minor amounts of habitat In areas previously
undisturbed by highway construction. Wildlife species that rely upon these areas for habitat
would be permanently displaced. Overall, the effects to wildlife would be minor.


Fisheries Impacts


Impacts to aquatic resources In No Name SprJng Creek and Spokane Creek as a result of the proposed highway
Improvements are expected to be minor. Impacts to aquatic resources In the project area would primarily result from direct
disturbance associated with culvert replacement, bridge replacements, and highway fill placement.


Threatened and
Endangered Species
Impacts


Reconstructing Canyon Ferry Road on any of the alignments proposed with these alternates would cause little. If any,
effects to threatened or endangered species.



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Canyon Ferry Road; STPS 430-1 (5) 1



Environmental Assessment



TABLE 5 (page 6 Of 7)





Alternate Intersection Configurations


Alternate 1


Alternate 2


Alternate 3

"Preferred Action"


Alternate 4


Land Use Impacts


This alternate has the
potential to relocate or
adversely affect the most
residences and a business
near the existing
Intersection.


This alternate would affect
more farmland than
Alternates 1 or 3. The
resulting road's grade would
be less favorable for the
development of new
approaches In the future.


This alternative would
require the relocation of four
residences and possibly a
mobile home, but would not
require the relocation of any
businesses. Few other land
use changes would be
expected.


This alternate would result in
impacts similar to those
associated with Alternate 2.


Noise Impacts


The noise Impacts
associated with this
alternate would be similar to
existing conditions. There Is
a potential for Increased
traffic noise as some
residences along the
roadway because eastbound
traffic on Canyon Ferry
Road would no longer be
required to stop. Higher
travel speeds could result In
Increased noise levels.


This alternate would result in
the least noise Impacts since
the new intersection would
be shifted far south of the
present Intersection and
away from noise sensitive
residences.


The majority of the existing residences where noise impacts
could occur would need to be relocated to accommodate the
new road. The potential noise Impacts of Alternate 4 would
be less than those of Alternate 3 because the new road
would be shifted further to the north of sensitive receptors.


Social Impacts-
Environmental Justice


This proposed Intersection reconstruction would not have any significant Impact on the location, distribution, density or
growth rate In this portion of Lewis and Clark County. These alternates would not adversely affect any social or ethnic
groups and It would not Isolate or divide existing residential areas.


Economic Impacts


This alternate would require
the acquisition of one
business and would convert
more agricultural land than
Alternates 2 or 4.


This alternate would result in
a greater disruption to
agricultural uses than other
alternates. Although it would
not directly impact any
commercial buildings.
Canyon Ferry Road would
Intersect Spokane Creek
Road some distance from
the present Intersection.
Some loss of revenue could
occur if patrons no longer
chose to stop at the
business.


This alternate would not
impact the business near the
present intersection.
However, it would require
the acquisition of the home
and outbuildings of a small
ranch. Alternate 3 would
have less impact to
agricultural operations than
Alternates 2 or 4.


Alternate 4 would not impact
the business near the
present intersection.
However, it would bisect one
ranch and require the
acquisition of the home and
outbuildings associated with
another small ranch.



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Canyon Ferry Road; STPS 430-1 (5) 1



Environmental Assessment



TABLE 5 (page 7 Of 7)





Alternate Intersection Configurations


Alternate 1


Alternate 2


Alternate 3

"Preferred Action"


Alternate 4


Historical and Cultural
Resources


This alternate would require
the reconstruction of the
Helena Valley Canal Bridge
located on Canyon Ferry
Road east of the present
Intersection. Main canals
and laterals associated with
the Bureau of
Reclamation's Helena
Valley Irrigation Unit
(24LC1C62) are considered
historic irrigation features.
The Bureau and the SHPO
agreed the proposed project
would not affect the Helena
Valley Irrigation Unit or
affect Its potential for being
eligible for the National
Register of Historic Places.

No other cultural properties
eligible for the National
Register were Identified that
would be affected by these
alternates.


No cuHural properties
eligible for the National
Register of Historic Places
would be affected by this
alternate. The alternate
would not affect the Helena
Valley Irrigation Unit
(24LC1062).

The potential for
encountering unanticipated
cultural materials Is
Increased as the alignment
crosses generally
undeveloped agricultural
land.


As with Alternate 1 . the Helena Valley Canal Bridge located
on Canyon Ferry Road east of the present intersection
would need to be reconstructed. However, the Bureau of
Reclamation and the SHPO agreed the work would not
affect the Helena Valley Irrigation Unit.

No other cultural properties eligible for the National Register
were Identified that would be affected by these alternates.


Section 4(f) and LWCF
Section 6(f) Impacts


No 4(f) or 6(f) Involvement would occur with any of the proposed Intersection configurations. A Section 4(f) evaluation would
not be necessary for effects to the Helena Valley Canal Bridge because the Bureau of Reclamation and SHPO do not
believe the project would affect the Helena Valley Irrigation Unit (24LC1 062).


Visual Impacts


Reconfiguring the Intersection of Canyon Ferry Road and Spokane Creek Road with the associated modifications to terrain,
the addition of lighting, and removal of several residences would also be a notable change. These highway modifications
would be noticeable to residents and highway users familiar with the previous roadway alignment of the road.



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Canyon Ferry Road
STPS430-t(5J t; Control No. 4480
Environmental Assessment



IV. ENVIRONMENTAL IMPACTS
AND MITIGATING MEASURES



Canyon Ferry Road; STPS 430-1(5) 1



Environmental Assessment



IV. Environmental Impacts and
Mitigating Measures



A. Introduction

Part IV describes the social, economic, and enviiomnental conditions and resources affected by
tlie proposed reconstruction of Canyon Feixy Road fiom Walter Drive to tlie project end just east
of tlie present intersection with Spokane Creek Road. Resources likely to be affected were
identified tliiough agency contacts, literature reviews, reseaich and field studies and public
involvement activities.

This Part also discusses the potential impacts of implementing the Preferred Action and of taking
no action. As indicated in Part III, the "Prefened Action" refers to the specific activities
associated with tiie proposed Canyon Ferry Road project including tiie reconfiguration of the
Canyon Ferry Road/Spokane Creek Road intersection. MDT does not consider the No Build
Alternative as viable because it fails to meet tiie purpose and need for the project. However, tiie
impacts of tins alternatrve are being analyzed for tiie purposes of providing a contiast or
comparison witii the Preferred Action. Only the impacts with a reasonable possrbility for
indivrdual or cumulatrve impacts are assessed under this section.

Where approprrate, measures to mitigate the adverse enviromiiental impacts of this project are
drscussed at the end of each section. If the Prefened Action is advanced, tiien MDT will
implement tiie mitigatmg measuies identified in this Fait.

B. Impacts to the Natural Environment



1. IMPACTS TO LANDFORMS, GEOLOGY AND SOILS



Existing Conditions. The Canyon Feiiy Road project area is located in the southwestern
portion of the Northern Rocky Mountains Pliysrographic Provmce of the United States and is
characterized by broad intermountain valleys between major mountain ranges. The proposed
project is located in tiie soutiieastern portion of tiie Helena Valley, a wide area west of tiie
Missouri River. This portion of the Helena Valley is bounded by the Elkliom Mountains to tiie
south and the Spokane Hills and Big Belt Mountains to the nortii and east. The Helena Valley
was formed in sedrments and alluvial deposrts fi'om volcanic rocks, shale, and sandstones in
surrounding uplands.

The Helena Valley is located witlun tiie Intermountain Seismic Belt, a seismically active zone
associated witii major geologrc fault stRictuies. This area has a hrstory of seismic activity,
including earthquakes m 1869 and 1935 (a quake that measured 6.3 on the Richter scale). Much
of this aiea is underlam with partially consolidated sediments saturated with groundwater, which
affect tiie probabrhty and magnitude of ground failme and stinctiiral damage in a seismic event.



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Canyon Ferry Road; STPS 430-1(5) 1 Environmental Assessment

Piickly Pear Creek drains the western two-tliirds of tlie project area witli tlie creek itself lytr^
immediately west of the project's begiiuiiiig. Prickly Pear Creek originates fiom the Elkliom
Mountains several km (miles) soutliof the project area and flows noitliwesterly through tliis
poition of the Helena Valley. Spokane Creek and its tiibutanes drain the eastern one-tliird of the
project aiea. The divide between the Prickly Pear and Spokane Creek drainages uses more tlian 60
m (200 feet) above tlie elevation of the two vaheys.

Surface elevations along this project generally increase from west to east until reaching tlie
"divide" at about RP 5.7 and then decrease towards Spokane Creek near the project's east end.
The elevation of Canyon Feny Road is about 1,151 m (3,775 feet) at the beginning ofthepioject
and varies in elevation by no more than about 1 m (30 feet) until about Lake Helena Drive.
East of this point, tlie highway rises to over 1,210 m (3,970 feet) in elevation where tlie road
enteis and traverses a portion of the Spokane Hills. The highway's elevation drops significantly
as tlie road traverses tlie Spokane Creek drainage and increases again shar'ply at tlie intersection
of Canyon Feny Road and Spokane Creek Road. The rise in tenain of more than 35 m (1 1 5 feet)
&om Spokane Creek to tlie bencMand near Keir Lane is a significant design consideiation for the
reconfiguration of the Canyon Ferry Road/Spokane Creek Road intersection. The highway's
elevation is about 1,187 m (3,895 feet) at the east end of tlie proposed project.

IMPACTS OF THE PREFERRED ACTION. The reconstruction of Canyon Ferry Road
would involve rebuildir^ an existmg segment of highway across terrain and landfonns located
beneath and adjacent to tlie present road. The proposed reconstruction would involve cutting and
fiUir^ to prepare a new foundation for tlie widened road and roadside slopes and to enhance the
road's vertical and horizontal ahgnment. These activities would disrupt, displace, compact and
cover soils not currently associated with tlie existing highway.

The design of the proposed project would be accomplished in a way that attempts to balance the
amount of cut and fill materials witliin tlie project area. This would minimize the need for
borrow sources away fiom the project area. Surface and subsurface materials would be disturbed
at locations away fiom the project areas if additional material were needed to build tlie new
roadway. Typically, MDT's contractor provides any additional material imported to construct
tlie proposed project.

The constiiiction activities, including clearing and grading, would increase the short-term and
long-term potential for soil erosion and sediment transport. This potential for erosion and
adverse sedimentation impacts would vary depending upon the amount of soil area disturbed, tlie
nature of the soils disturbed, tlie steepness of slopes, tlie proximity of the disturbance to wetlands
and surface waters, and tlie duratron of tlie soil disturbances.

A Stoirii Water Pollution Prevention Plan (SWPPP) would be designed for the Canyon Ferry Road
project and submitted to the MDEQ Permitting and Comphance Drvision in accordance with
tlieu' Montana Pollutant Discharge Elimination System Regulations (ARM 16.20.1314) . Best
Management Practices, mcluding temporary and long-term erosron control measures, would be
consideied m the design of tlie Plan. Such practices may mclude the use of lined channels, silt
fences, ditch blocks, mulch, slope protection and other commonly accepted control measures.
The SWPPP would be developed using procedures and methods established in MDT's "Erosion
and Sediment Contiol Best Management Practices: Reference Manual" whose main objective is

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Canyon Ferry Road; STPS 430-1(5) 1 Environmental Assessment

to minimize erosion of disturbed areas during andafterconstiuction of these proposed projects.


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Online LibraryRobert Peccia & AssociatesEnvironmental assessment and nationwide section 4(f) evaluation Canyon Ferry Road : STPS 430-1(5)1; CN 4480, Lewis and Clark County, Montana (Volume 2003) → online text (page 6 of 19)