19970616 Ver 1_More Info Received_19980327

JATr ;
STATE OF NORTH CAROLINA
DEPARTMENT OF TRANSPORTATION
JAMES B. HUNT JR_
GOVERNOR
P.O. BOX 25201. RALEIGH. N.C. 27611-5201
E. NORRIs ToLSON
s-.TAaETARY
March 27, 1998
Mr. William L. Cox, Chief
Wetlands Section
Wetlands, Coastal, and Water Quality Grants Program
U.S. Environmental Protection Agency, Region 4
Atlanta Federal Center
61 Forsyth Street, S. W.
Atlanta, GA 30303
Dear Mr. Cox_
Re: U.S. 421, Watauga County
Action ID No. 199707161
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On March 25, 1998, we were given for the first time a copy of your February 5,
1998 letter to the Asheville Office of the U.S. Army Corps of Engineers regarding the
above-referenced project by the N.C. Division of Water Quality (DWQ). We would have
responded to you earlier if we had been copied along with the DWQ and the Raleigh
Office of the U.S. Fish and Wildlife Service. (Please copy us on future correspondence
of this nature.) Our response to your two comments is as follows:
1. Median and Right of Way Widths. The NCDOT's proposal to use a 46 ft. median on
the subject project is based on "A Policy on Geometric Design of Highways and Streets"
developed by the American Association of State Highway and Transpiration Officials
(AASHTO), Standing Committee on Highways. The Committee was established in 1937
to formulate and recommend highway engineering policies. The guidance supplied by
AASHTO is based on established practices and is supplemented by research and is
intended to provide operational efficiency, comfort, safety and convenience for motorists.
According to AASHTO, the principal function of a median on an expressway
facility such as US 421 is to separate opposing traffic, provide a recovery area for out-of-
control vehicles, provide a stopping area in case of emergencies, and minimize headlight
glare. Medians should be as wide as feasible, and where possible, should be such that a
median barrier is not warranted. A median should be of sufficient width to provide
adequate shelter for vehicles crossing at crossovers. Insofar as traffic is concerned, a
sense of physical and psychological separation from opposing traffic is obtained when
medians are about 12 in. (40 ft.) or wider. With such widths traffic is truly divided. The
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noise and air press ure of opposing traffic is not noticeable and at night headlight glare is
greatly reduced.
Based on PASHTO, the NCDOT has determined a 60 ft. median is desirable for
roadways posted for speeds 55 mph or higher. A 46 ft. median on such facilities is
considered the miriimum width acceptable, except under extraordinary circumstances.
The right cif way limits for the subject project were established based on
topographic constraints. US 421 between Deep Gap and the South Fork New River is
located in the mountain region of Northwestern North Carolina. A maximum desirable
vertical alignment for the proposed expressway type facility was established at four
percent. However the terrain was such that grades of approximately six percent were
required in some areas to limit the impacts of the proposed roadway. Cut and fill slopes
were established alt. 2:1 or steeper were practicable. Regardless of the efforts to make
slopes steeper and to increase grades, the footprint of the roadway extended as much as
500 ft. in areas of eextrerne terrain. In these areas the width of the right of way was
established at a width sufficient to contain the slopes. In areas of less extreme terrain,
right of way widthLs were reduced to a little as 110 ft.
2. Wetland and Stream Mitigation. The wetland mitigation for all of the highway
project's wetland i,,rnpacts is being proposed at the Sparta Bog. This site will also provide
some of the 11,272 ft. of stream mitigation required (5,636 ft. at a 2:1 ratio), however the
exact amount will not be known until the mitigation plan is complete. To address the (as
yet unknown) balaEnce, the NCDOT is entering into a contract with the N.C. Wildlife
Resources Commission (WRC) to identify and implement up to 11,272 ft. of stream
mitigation in the highway project's area.
To better discuss the wetland and stream mitigation issues you raised in your
letter, we have enclosed a copy of a document entitled "Wetland and Stream Mitigation
Strategy for US 421" dated March 27, 1998, which we prepared at the request of the N.C.
Division of Water Quality. This document includes a copy of the proposed DOT/WRC
contract. If you have any questions, please contact me directly at 919-733-7844, Ext.
310, or e-mail me at "[e-mail]."
Sincerely,
V_-ra
tDavid C. Robinson, Ph.D., P.E.
Assistant Manager - Environmental Services
Enclosure
cc: John Dorneyl/
Steve Lund
Gail Grimes