Building a Turnagain Arm Bridge: A Feasibility Study
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Transcript Building a Turnagain Arm Bridge: A Feasibility Study
Building a Turnagain
Arm Bridge: A
Feasibility Study
ENGL 212: Technical Writing
Bryce Eckroth
Overview
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Introduction
Criteria
Methods
Research Results
Conclusions
Recommendations
Introduction
• Examined the feasibility of constructing a bridge spanning the
Turnagain Arm from Anchorage to the city of Hope.
• Researched public safety statistics along the Seward Highway
corridor that this proposed bridge would circumvent to determine
project need.
• Determined economic, public safety, and environmental effects that
the bridge would have on South-central Alaska.
• Identified if the proposed Turnagain Arm Bridge Project is
environmentally and economically feasible.
Feasibility Criteria
• Would the construction of a bridge spanning Turnagain Arm from
Windy Pt. to the town of Hope be financially and physically possible?
• Would the construction of this bridge project effectively mitigate
risks to Seward highway users by skipping 60 miles of the current
route? Is there a current need for reduction in risks?
• Would there be any significant environmental impacts created by
the construction of this project?
Methods
• Created & disseminated a questionnaire, in which participants were
asked about: demographics, commuter habits along the Seward
Highway South of Anchorage, interest/ feelings about a proposed
bridge spanning the Turnagain Arm, and effects of such a bridge on
Kenai Peninsula economy, the environment, and public safety.
• Reviewed similar construction projects across Alaska. Focused
directly on feasibility studies & reports of a similar bridge spanning
the Knik Arm.
• Analyzed AK Department of Transportation & Public Facilities
statistics regarding commuter public safety along the Seward
Highway along the Turnagain Arm.
Methods
• Reviewed Environmental and geological reports of a highly similar
report to determine effects of this bridge on the environment and
whether or not it could physically be built.
• Reviewed economy statistics, figures, and projections of Southcentral Alaska Economies.
Research Results
• Physical Aspects and Economics of Construction:
• Quaternary geology of the Turnagain Arm is conducive to building
such a bridge.
• Highly similar Knik Arm Crossing project cost estimated at $650$750 million dollars, with a roughly $1 million per year cost of
operation.
• Strong population growth rate of 1.72% per year has Southcentral Alaska’s population growing by over 50% in the next 25
years.
• Study conducted shows public interest in proposed bridge’s
economic benefits.
Research Results
• Physical Aspects and Economics of Construction
• “Do you think lower Kenai Peninsula economies such as Seward,
Soldotna, and Homer, would benefit from this bridge’s construction?”
4
14
Yes
No
Research Results
• Risk Mitigation
• From 2001-2007, 121 vehicle crashes occurred along this stretch of the
Seward Highway resulting in fatalities or major incapacitating injuries.
• Challenging road conditions are present due to the physical topography,
weather, and variety of user groups.
• Average vehicle trips sometimes exceed 16,300 vehicles per day,
cramping this dangerous stretch of 2-lane highway. Primary research
supports this popularity.
“How many times per month do you travel on the Seward highway South
of Anchorage?”
4+ (I am a
regular
traveler)
21%
1 to 4
32%
0
47%
Research Results
• Environmental Impacts
• Similar bridge construction effects on Cook Inlet Beluga Whale
populations has been shown to be not detrimental to normal
feeding or migratory routes.
• Sediment displacement or erosion from the bridge’s bridge
supports would be expected to be negligible.
• Mainland connections of the proposed bridge would be spaced so
as not to interfere with shoreline migration routes of salmon and
smelt species.
• Dramatic figures of carbon footprint reduction will be realized
due to fuel consumption savings with the bridge’s use. A similar
bridge projected into the year 2025 totes a net savings of
approximately 6.2 million gallons of fuel and over 66,000 metric
tons of carbon dioxide by Anchorage commuters.
Research Results
• Environmental Impacts
• Public opinion is in favor of infrastructure development in Alaska.
Pie slices 1 and 3 represent the majority of survey respondents
who thought that bridge projects like the Turnagain Arm project
could be constructed to be harmonious with the environment.
4
29%
1
18%
3
47%
2
6%
Conclusions
• The data from the geological surveys, economic analysis, population
studies, and review of KABATA KAC construction cost estimates
indicate that building a bridge spanning the Turnagain Arm could be
both physically and financially possible.
• AKDOT&PF highway safety studies indicate there is a need for
reduction in risk to commuters on the Seward Highway.
• Environmental impact studies conducted on a similar project scope
elsewhere in the state of Alaska indicate the construction of a bridge
such as that proposed across the Turnagain Arm would not
negatively impact the surrounding ecosystem. That, combined with
an additional reduction in carbon footprint over the bridge’s lifespan
would make the bridge environmentally feasible to construct.
Recommendations
• An additional study be conducted researching the effects to public
safety of bridge construction circumventing dangerous stretches of
highway.
• A more comprehensive questionnaire be disseminated to a larger
group of Seward Highway commuters in order to make a precise
determination on their feelings regarding bridge construction,
current Seward Highway public safety statistics, and toll road use.
• The Alaska Legislature designates a board similar to the Knik Arm
Bridge and Toll Authority which centers on building a Turnagain Arm
toll bridge.