Meeting Notes - Knik Arm Bridge and Toll Authority

Meeting Notes
Robin Reich (HDR)
We haven’t made a decision yet on abutment type. We are looking for feedback.
Doug Kenley (PND)
The 10:1 abutment slope would decrease the navigation space. It may still be adequate.
Heather Dean (EPA)
Did you look at the option of combining options 1 and 4, having sheet pile with a 2:1 slope?
Michael Allwright (HDR)
The primary reason to have sheet pile is to reduce the length of the slope. Also, the sheet pile
would not slow down the current.
Robin Reich (HDR)
One of the alternatives to get into Anchorage is the below the bluff roadway. It would have
gravel fill along the bluff with armor rock on the waterside of the alignment. Doug will
explain the design options for the below the bluff alignment.
Doug Kenley (PND)
One option would be to have a 4-lane roadway with a 2.1 side slope. This alternative would
have a footprint of about 32 acres at a cost of $19 million. Roadway fill would extend 175 ft
from the bluff into the tidelands.
Another option would be a 4-lane roadway with a 10.1 side slope with a footprint of about 92
acres at a cost of $73 million. Fill would go out 575 ft from the bluff to the tidelands.
Another option would be a 4-lane roadway with a 10:2 benched slope. This option would
have a footprint of about 55 acres and cost $35 million. Fill would extend out 300 ft into the
tidelands. In Puget Sound the benched option is used to re-create salt marsh habitat which
does not occur in this area of Knik Arm.
Michael Allwright (HDR)
In British Columbia spur dikes have been used to replace salt marsh. They have a 30%
increase in net habitat.
Robin Reich (HDR)
In that example project we looked at, the area between spur dikes grew into green lush
marshes. They had a different purpose. Here they could be like a lot of little barriers for the
fish movement.
Skip Joy (COE)
The spur dike option doesn’t look good to me.
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