20000176 Ver 1_COMPLETE FILE_19920101

Environmental Review Tracking Sheet
D vVQ - Water Quality Section
Date: aj's199 r ,
MEMORANDUM i
Ta. Env. Sciences Branch (WO Lab)
O Trish MacPherson (end. sps) °-
O Kathy Herring (forest/ORW/HQW)
O Larry Ausley (ecosystems)
O Matt Mathews (toxicology)
p''Jay Sauber (intensive survey)
Non-Discharge Branch (Archdale _9th)
O Kim Colson (Permitting)
Wetlands (WQ Lab)
hri -Dozpey (Corps, 401, construction)
p Cyndi Bell (DOI)
0 Eric Fleek (dredging)
O

DENR # o kkl
qB i o w DWQ # a 3 y?
.vs
a
TEAR U y!OUP
N
N
Regional _Water Oualitv SuDervi rs
O Asheville O.Mooresville O Washington
O Fayetteville O Raleigh O Wilmington
0 Winston -Salem
Planning Branch (Archdale 6th)
O Alan Clark (basinwide planning)
O Boyd DeVane.(class cations & standards)
O Annette Lucas (management planning)
O Jeff Coutu (water supply)
0 Ruth Swanek (modeling) (Archdale 9th)
Point Source Branch (Archdale 9th)
0 Dave Goodrich (NPDES) O
0 Bradley Bennett (Stormwater) O
0 Tom Poe (Pretreatment) (Archdale 7th) O
FROM: Gloria Putnam, Local Government Assistance Unit, Planning Branch, 6th Floor, Archdale
PROJECT:
W
Attached is a copy of the above document. -Subject to the requirements of the North Carolina Environmental
Policy Act, you are being asked to review the document for potential significant impacts to the environment,
especially pertinent to your jurisdiction,--level of expertise or permit authority. Please check the appropriate
box below and return this form to me along with your written comments,-if any,-by the .date indicated.

I can be reached at:
phone: [phone], ext. 567 fax: [phone] e-mail: '[e-mail]
misAcircmemo - mac version
Thank you for=your.assistance_ Suggestionsfor-veamhning.thisprocessmre greatly:appreciated! .
Notes:
February 15, 1999
MEMORANDUM
TO: Gloria Putnam
THROUGH: John Dorn
FROM: Eric Fleekf F
SUBJECT: Scoping Letter-Wilmington Harbor Improvement Comments (NCDWQ# 12346; DENR# 99-
E-0441)
Based on a review of the scoping letter, the following comments are offered:
1) There are numerous PNAs located adjacent to the project limits. Previous NCDWQ requirements
included turbidity (and other physical monitoring) in and near PNAs during hopper overflow dredging.
Additional widening of portions of channel which are already near PNAs could cause increased
incidences and or magnitudes of turbidity and other physical (and biological) alternations in PNAs.
Please include specific information in the EA regarding how far the new proposed channel widenings
are to PNAs. In addition, please elaborate upon any alterations to the hopper dredging overflow-
monitoring plan to reflect the closer proximity of dredging to any PNAs. A detailed map showing
channel limits (previous and proposed) in relation to PNAs would be helpful.
2) Please elaborate on what physical and environmental impacts are (or thought to be) specific to
dredging in an ODMDS. Additionally, please detail how this proposed project will alter the current
ODMDS in terms of usefulness and if a new ODMDS will need to be established or if the existing one
will require expansion to compensate for any loss in use (i.e., storage) due to dredging.
3) Please detail the advantages/disadvantages of expanding nearby existing diked disposal areas
versus the creation of a completely new one in Snow's Cut.
If there are any questions regarding this matter please feel free to call Eric Fleek at 919-733-1786 or at
eric-fleek @ h2o - enr. state. nc. us
DEPARTMENT OF THE ARMY
WILMINGTON DISTRICT, CORPS OF ENGINEERS
P.O. BOX 1890
WILMINGTON, NORTH CAROLINA 28402-1890
IN REPLY REFER TO 28 January 1999
Environmental Resources Section
Dear Sir or Madam:
The Wilmington District, U. S. Army Corps of Engineers, will soon complete the
planning and design for congressionally authorized improvements for Wilmington Harbor,
North Carolina, that are scheduled to start construction in September 2000. The
improvements will reduce shipping costs by alleviating navigation constraints that now
require larger vessels to leave the harbor lightloaded or to wait for high tide.
Consequently, the economic viability of the port will improve. Details of the improvements
have been planned, designed, and coordinated with the public over a period of several
years. As a result, the overall plan is comprehensive and addresses the many needs and
concerns identified. However, additional engineering, economic, and environmental
analysis has led us to propose a new alignment for the entrance channel through the
ocean bar (Baldhead Shoal Channel). We are now requesting comments from agencies,
interest groups, and the public to identify and discuss significant resources and issues
related to selection of a preferred alignment for this entrance channel.
The existing plan integrates harbor improvements that were recommended and
approved separately as the (1) Wilmington Harbor - Northeast Cape Fear River project;
(2) Wilmington Harbor - Channel Widening project;.and (3) Cape Fear - Northeast Cape
Fear Rivers project. This plan provides for increasing the authorized navigation depth of
the 40-mile-long channel from the Atlantic Ocean to the Port of Wilmington by 4 feet and
widening selected portions of the project. It includes authorized project depths to -44 feet
mean lower low water (m.l.l.w.) through the ocean bar, then -42 feet m.l.l.w. up the Cape
Fear River to and including the Anchorage Basin immediately upriver from the State Ports
Authority (SPA) dock, then -38 feet m.l.l.w. upstream into the Northeast Cape Fear River
to 750 feet beyond the Hilton Railroad Bridge, and finally -34 feet m.l.l.w. upriver to the
turning basin near the upstream limits of the project. In addition, an overdepth zone of 2
feet is allowable for dredging inconsistencies throughout the project length, and 1 foot of
additional overdepth is required in areas of rock. Project horizontal expansions include:
widening Lower Midnight, Upper Midnight, and Lower Lilliput Channels from 400 to 600
feet over a distance of 6.2 miles; widening five turns and bends by 100 to 200 feet;
widening the Fourth East Jetty Channel from 400 to 500 feet over a span of 1.5 miles;
extending the Anchorage Basin near the SPA upstream 300 feet; widening the channel in
-2-
the Northeast Cape Fear River from 200 to 250 feet, starting 750 feet upstream of the
Hilton Railroad Bridge and proceeding upstream to the turning basin near the project
limits; and widening this turning basin from 700 to 800 feet. General geographic features
of the harbor are shown in figure 1.
Sediments dredged from the upper harbor in the vicinity of the SPA and downtown
Wilmington will be placed in diked upland sites at Eagle Island and Point Peter. Material
from the middle and lower harbor may be transported to a proposed new Ocean Dredged
Material Disposal Site (ODMDS) located about 6 to 10 miles offshore from Baldhead
Island, or, if the material is beach-compatible sand, it may be deposited on nearby
beaches. While the harbor improvements are economically justified based upon this
disposal plan, considerable cost savings are likely if a new diked disposal facility could be
made available near Snows Cut to accommodate mid-harbor sediment rather than
transporting it the long distance to the ocean. Due to the complexity of the issues and the
length of time necessary to develop a plan for such a new diked disposal facility, this
concept will be addressed in a separate study in the near future. Mr. Frank Yelverton of
this office (telephone [phone]) will coordinate that study.
The existing plan for the ocean bar channel is to deepen it along its current
alignment and to extend its present length of 5.8 miles to a new total length of 9.3 miles
seaward from the inlet. However, this path passes through very hard rock bottom.
During 1996 and 1997, we attempted to deepen the existing channel to -40 feet m.l.l.w.
by rock dredging but achieved only limited success. We have determined that further
deepening would require extensive blasting and would be very slow and expensive. In
addition, ocean bottom surveys conducted in 1998 revealed that the seaward extension
of the present channel would pass through a substantial amount of live coral and other
valuable live hard bottoms. ,,? have searched for a more cost effective and
environmental) table alternative an ve identified w c anne rridor that
avoi s rock:; bo \a --?
shorter distann?irP 1. We are now conducting studies and analyses to assist in the
refinement of this channel alignment. Ship simulation studies are being conducted, with
assistance from the river pilots to help determine the optimal location and angle for a new
channel bend that may be required. Sediment budgets are being developed and will be
used with wave and current studies to evaluate the impacts of various channel alignments
on littoral processes over time. Assessments will also be made of the effects of channel
alignment on erosion rates at nearby beaches and whether mitigation may be required to
offset associated sand losses. The answers to these and other pertinent questions will
be developed over the next several months.
-3-
Construction of the ocean entrance channel along an alternative alignment is
expected to require removal of approximately 10 million cubic yards of sediments
consisting of sands, silts, and clays. Approximately 550 acres of existing ocean bottom
habitat would be disturbed along the 6.7 mile channel and its side slopes. In addition,
annual maintenance dredging would likely produce about 1 million cubic yards of material
per year. Depending upon the final alignment selected, these estimated quantities may
change. Material dredged from the new channel would be placed at the proposed
ODMDS, or if sand of sufficient quality and quantity could be obtained, it may be cost
effective to place it on the beach(es) at Bald Head Island and/or Oak Island. Dredging
operations may utilize hydraulic pipeline or hopper dredges, bucket and barge dredging,
or spider barges.
Channel construction and maintenance could cause adverse impacts on significant
resources present in the vicinity. These may include: endangered/threatened species;
marine, estuarine, and beach habitat; marine and estuarine life; cultural resources,
including important historic shipwrecks; recreational and commercial fisheries; and water
quality. In addition, the alternative channel alignment would pass through the existing
ODMDS rendering part of it no longer serviceable and requiring a new ODMDS, as noted
above. The environmental impacts of the alternative channel alignment would be partially
offset by gradual reversion of the existing ocean bar channel to a natural condition after
its maintenance dredging ceases. In addition, the plan would be dropped to extend the
existing channel 3.5 miles seaward through live coral and other live hard bottom.
In summary, we believe that an alternative channel alignment would be
advantageous for a number of reasons. These include: (1) avoiding rock bottom with a
resulting estimated saving of over $40 million in channel construction cost; (2) avoiding
coral/live hard bottom in the path of extending the existing alignment; (3) shortening the
distance to natural deep water (i.e., the -46-foot contour) to about 6.7 miles rather than
9.3 miles on the existing alignment; (4) avoiding the need for rock blasting and its
associated environmental impacts; (5) reducing channel construction time; (6) avoiding 1
foot of extra overdepth that would be required in areas where the channel bottom is rock;
and (7) locating the channel where future deepening, if required, would not be restricted
by rock.
Potential disadvantages of this plan include: (1) creating another channel bend
affecting navigation; (2) environmental impacts of dredging along a new path on the
ocean floor; (3) potential temporary interruptions of fishing/shrimping activities;
(4) alignment of the new channel through the existing ODMDS; and (5) potential alteration
of wave and current effects on channel shoaling and/or shoreline erosion at nearby
beaches.
-4-
Written comments are requested on any of these matters. Responses to this letter
will be considered during our selection of a final channel alignment and our assessment
of potential impacts on the environment. Significant issues will be addressed, as
appropriate, in an Environmental Assessment or Environmental Impact Statement.
Letters should be addressed to the District Engineer, Attention: Mr. John Meshaw
(CESAW-TS-PE), U.S. Army Corps of Engineers, Wilmington District, Post Office Box
1890, Wilmington, North Carolina 28402-1890. Please send your comments to arrive
within 30 days from the date of this letter in order that they may be considered during our
evaluations and decision process. If you need 'additional information, please contact
Mr. Meshaw at [phone].
Sincerely,
?0- W. COLEMAN LONG
Chief, Planning & Environmental Branch
Enclosure
END OF FEDERAL
PROJECT (30.8 MI) T O
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MILEAGES ARE MEASURED WILMINGTON HARBOR CHANNELS
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PROPOSED DOMOS LOCATED
SCALE IN FEET SEAWARD OF THIS AREA