U-5828 alternatives memo

May 3, 2016
Eric Alsmeyer, US Army Corps of Engineers
Rob Ridings, NCDENR Division of Water Resources
Charles Cox, NCDOT Project Development and Environmental Analysis
RE:
Project U-5828 (McCrimmon Parkway) Alternative Comparison
Six conceptual alignments were considered for Project U-5828, McCrimmon Parkway from Airport
Boulevard (SR 3015) to Aviation Parkway (SR 1002) as shown on the attached figures. Alternative 6
has been identified as the preferred alternative.
The following table summarizes the potential estimated wetland and stream impacts for all six
alternatives based on GIS data from the National Wetland Inventory (NWI) and NC Division of Water
Resources (DWR). Tables 1 and 2 also list potential estimated wetland and stream impacts for
Alternative 6 (the preferred alternative) based on delineations of field-verified features.
None of the alternatives are expected to require relocations or impact historic or community
resources. Additionally, no threatened or endangered species are expected to be impacted by the
alignments.
Table 1: Estimated Stream and Wetland Impacts
Actual Delineated
Estimated GIS Impacts*
Impacts
Length
Alternative
(ft)
StreamsWetlandsStreamStreamsWetlands
(lf)(ac)Crossings(lf)(ac)
17,8002,3800.410
27,8002,53607
37,7002,08307
47,3001,46505
57,2001,32104
6 (Preferred) 7,7002,288< 0.183760.9
Note: The delineated streams and wetlands in the study area vary from the GIS data. However, the
GIS data is appropriate to use for comparing potential alignments.
* Estimated Impacts are based on a 210-foot wide corridor along each alignment centerline. The 210-
foot width includes an average 160-foot construction limit width with a 25-foot buffer on either side.
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Table 2: Estimated Delineated Impacts for the Preferred Alternative
Alternative 6Actual Delineated Impacts
(Preferred)
Streams (lf)Wetlands (ac)
Site 10.1
Site 264< 0.1
Site 30.1
Site 4740.2
Site 50.1
Site 62390.1
Site 70.3
Total3760.9
Note: Actual delineated impacts are based on the preferred
alternative slope stakes and are subject to change slightly as
final design progresses.
Several factors contributed to the selection of Alternative 6 as the preferred alignment:
Reserved right-of-way east of Airport Boulevard –
This right-of-way was reserved for the
purpose of the extension of McCrimmon Parkway. Alternative 6 utilized this area to minimize
additional right-of-way impacts to property owners.
Property impacts –
Property owners along the corridor participated in meetings with the
project team during the alternate selection process. Alternative 6 was adjusted to allow for
more equal “property swaps” where corners of two properties were split to allow property
owners to maximize their developable land while minimizing remnant parcels.
Environmental impacts –
Alternative 6 was designed so that no relocations or historic or
community impacts are expected. No threatened or endangered species are expected to be
impacted. Potential impacts to the Northern Long-Eared Bat will be handled under the
current programmatic agreement between NCDOT, FHWA, and USFWS. Actual delineated
stream impacts (376 lf) are lower than the estimated GIS stream impacts and will be less
than the USACE Nationwide Permit threshold.
Construction cost
– To avoid higher earthwork costs, Alternative 6 was shifted north to
balance cut/fill volumes and to avoid steep terrain.
Alternatives 1, 3, 4, and 5 have similar levels of anticipated natural environment impacts to Alternative
6 but conflict with the future Wake County Competition Center project. Alternative 2 does not conflict
with the future Wake County Competition Center project but has higher levels of anticipated natural
environment impacts than Alternative 6. Alternative 5A, a modified version of Alternative 5, was
developed to avoid impacts to Sites 1 and 2 before tying back into the preferred alternative. However,
to avoid Sites 1 and 2, Alternative 5A has an unfavorable horizontal curve design, generally avoided
by NCDOT. Additionally, Alternative 5A would create impacts to the pond located near Site 3 and
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would still result in impacts to Site 3. Additional avoidance and minimization may be possible during
final design.
Conclusion:
Given the geometric constraints of the existing intersection of McCrimmon Parkway at
Airport Boulevard, the future Wake County Competition Center project, the existing intersection of
Evans Road at Aviation Parkway, and the environmental features along the corridor, Alternative 6 is
recommended for selection. This recommendation is based on the limited environmental impacts
associated with the preferred alternative and the support of the impacted property owners along the
corridor.
Processing of this project under a Nationwide Permit has been agreed to by USACE staff at a pre-
application meeting that was held on October 6, 2015. Additionally, it was agreed to assign required
mitigation ratios on a per feature basis.
The USACE Action ID for the project is SAW-2014-02205, and the project contact is now Eric
Alsmeyer. The DWR project ID is 14-304, and the project contact is Rob Ridings.
Sincerely,
Aaron Heustess
NEPA Project Engineer
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