19970625 Ver 1_COMPLETE FILE_19970714

State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
James B. Hunt, Jr., Governor
Wayne McDevitt, Secretary
A. Preston Howard, Jr., P.E., Director
1 00
Wow
NCDENR
NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
August 18, 1998
Mr. Frank Yelverton
Wilmington District, Corps of Engineers
P.O. Box 1890
Wilmington, N.C. 28402-1890
SUBJECT: Hopper Overflow Dredging Monitoring Plan Comments
Wilmington Harbor
New Hanover County
Dear Mr. Yelverton:
After a careful review of the August 1998 monitoring plan for hopper dredge
overflow in Wilmington Harbor, the 401 Wetlands Unit has no objection to the plan as
proposed and concurs with its content and purpose.
If you should have further comments or questions regarding the conditions of
your 401 Water Quality Certification for this project please feel free to call myself or Mr.
Eric Fleek at (8919) 733-1786.
Sincerely,
4Wter orney
Quality Certificati Program
Cc: Joanne Steenhuis, NCDWQ Wilmington Regional Office
Wetlands/401 Unit 4401 Reedy Creek Road Raleigh, North Carolina 27607
Telephone [phone] FAX # [phone]
An Equal Opportunity Affirmative Action Employer 50% recycled/10% post consumer paper
DEPARTMENT OF THE ARMY
WILMINGTON DISTRICT, CORPS OF ENGINEERS
P.O. BOX 1890
WILMINGTON, NORTH CAROLINA 28402-1890
August 7, 1998
IN REPLY REFER TO
Environmental Resources Section
Mr. John Dorney, Director
PEWITLAWNDI 1 3 1?
Wetlands Unit 00"
North Carolina Division of Water Quality w:?TEa QuA?iTv
4401 Reedy Creek Road
Raleigh, North Carolina 27607
Dear Mr. Dorney:
Consistency determination CD97-26 was issued October 6, 1997, and 401 Water
Quality Certificate No. 3157 was issued September 26, 1997, for the overflow of hopper
dredges in the Wilmington Harbor in Wilmington, North Carolina. The conditions of
these documents required that a plan be developed for monitoring the overflow plume.
A draft monitoring plan was reviewed by several agencies at a meeting in Wilmington,
North Carolina, on August 4, 1998. Agency attendees included Mr. Jim Gregson,
Division of Coastal Management; Ms. Joanne Steenhuis, Division of Water Quality;
Mr. Fritz Rohde, Division of Marine Fisheries; and Mr. Bennett Wynne, Wildlife
Resources Commission. Representatives from the U.S. Fish and Wildlife Service and
the National Marine Fisheries Service were invited but were not able to attend;
however, comments were received from them by phone.
Enclosed for your review is the proposed final monitoring plan which incorporates
the comments received on the draft plan. Please indicate in writing by A U-, dust 26,
1998, if you concur with the plan.
Any questions regarding this matter should be directed to Mr. Frank Yelverton,
Environmental Resources Section, at [phone].
Sincerely,
L
W. Coleman Long
Chief, Planning and
Environmental Branch
Enclosure

MONITORING PLAN TO DETERMINE POTENTIAL EFFECTS
OF TURBIDITY AND SUSPENDED SOLIDS PLUME
ASSOCIATED WITH HOPPER DREDGE OVERFLOW IN THE
WILMINGTON HARBOR, NORTH CAROLINA
Prepared For:
Wilmington District Corps
U.S. Army Corps of Engineers
P.O. Box 1890
Wilmington, NC 28401
Prepared By:
CZR INCORPORATED
4709 College Acres Drive, Suite 2
Wilmington, North Carolina 28403
August 1998

Contract No. DACW54-97-D-0028
Delivery Order 004
MONITORING PLAN TO DETERMINE POTENTIAL EFFECTS
OF TURBIDITY AND SUSPENDED SOLIDS PLUME
ASSOCIATED WITH HOPPER DREDGE OVERFLOW IN THE
WILMINGTON HARBOR, NORTH CAROLINA
Prepared For:
Wilmington District Corps
U.S. Army Corps of Engineers
P.O. Box 1890
Wilmington, NC 28401
Prepared By:
CZR INCORPORATED
4709 College Acres Drive, Suite 2
Wilmington, North Carolina 28403
1.-,/ L."
Samuel Cooper
Project Manager
S 4;?? 199g
Date
MONITORING PLAN TO DETERMINE POTENTIAL EFFECTS OF TURBIDITY AND
SUSPENDED SOLIDS PLUME ASSOCIATED WITH HOPPER DREDGE OVERFLOW IN THE
WILMINGTON HARBOR, NORTH CAROLINA
1. INTRODUCTION / BACKGROUND
Disposal area capacity for the routine maintenance dredging of Wilmington Harbor is limited in
the Cape Fear River downstream of Eagle Island. Therefore, most of the maintenance material dredged
from the harbor downstream of Eagle Island is disposed in the ocean at the Wilmington Harbor Ocean
Dredged Material Disposal Site (ODMDS). One method for harbor maintenance and disposal at the
ODMDS is using a hopper dredge with overflow. Use of a hopper dredge with overflow as an additional
maintenance dredging method for portions of Wilmington Harbor was addressed in an Environmental
Assessment (July 1997) and a Finding of No Significant Impact (November 1997) prepared by the U.S.
Army Corps of Engineers, Wilmington District. Approval has recently been obtained to use this method
in the harbor downstream of Eagle Island, but monitoring of the overflow plume in portions of the harbor
has been required as a part of the North Carolina Division of Water Quality's (DWQ) Section 401 Water
Quality Certificate No. 3157 issued 26 September 1997 and North Carolina Division of Coastal
Management's (DCM) Letter dated 6 October 1997 (Appendices A and B, respectively).
The purpose of this monitoring plan is to address methods that will identify potential adverse
impacts to the water quality and natural resources that could result from overflow dredging methods.
The primary focus of additional hopper dredge monitoring will be to determine if dredged material
overflow will be contained within the limits of the ship channel or deposited in the adjacent shallow
waters of primary nursery areas (PNA). PNAs are often used by shrimp, crabs, and fish during post-
larval development. If the overflow from hopper dredging results in fine sediments leaving the channel
and accumulating in adjacent PNAs, the area of bottom affected and the depth of sediment accumulation
will be determined. Detecting impacts will be determined by monitoring turbidity, suspended solids,
sediment deposition, and benthic macroinvertebrates. This monitoring plan has been developed in
accordance with the following conditions:
DWQ's Section 401 Water Quality Certification (No. 3157):
1) If dredging [with overflow] is done in locations with less than 90% sand, water
quality data shall be collected by the U.S. Army Corps of Engineers for total and
suspended residue and turbidity to determine the lateral extent of the sediment
plume above background levels into adjacent PNA as well as the extent and
thickness of the sediment redeposition on the channel flanks.
2) If the sediment plume extends above background levels into the PNA, the effect of
sediment redeposition on benthic organisms in the PNA shall be documented by the
U.S. Corps of Engineers by monitoring pre- and post benthic abundance and
diversity in areas adjacent to the channel in the adjacent PNA where redeposition
is observed. The monitoring shall be at intervals for up to 1-1 /2 years or until
background levels of benthic organisms are achieved. Written approval from DWQ
is required for the monitoring plan before dredging utilizing hopper dredge when
overflow is implemented.
5 August 1998
3) If results from water quality and monitoring reveal significant environmental impacts,
this 401 Certification may be modified to reflect these impacts. Similarly if the
monitoring reveals a lack of environmental impact, this certification maybe modified
to remove these monitoring requirements.
DCM's consistency letter:
1) All conditions of the 401 Water Quality Certification issued by the N.C. Division of
Water Quality are met. This Certification must remain active for hopper dredge with
overflow to be used within portions of the channel authorized herein.
2) The Division of Coastal Management shall be provided the opportunity to review and
comment on any monitoring plans that are implemented as prescribed by the
conditions of the 401 Water Quality Certification. The Division of Coastal
Management will be provided a copy of the results of any monitoring for review.
3) Aerial photography shall be obtained to monitor the movement and dissipation of the
sediment plume as part of the project. Aerial photography will provide valuable
visual data to complement water quality observations and or sampling. Site
conditions for flight should be coordinated with the Division of Water Quality and
Jim Gregson of the Division of Coastal Management (919/395-3900).
4) Discharge within the mixing zone must not result in acute toxicity to aquatic life or
prevent the free passage of aquatic organisms.
5) The Corps of Engineers will continue its efforts to develop a Dredged Material
Management Plan for the Cape Fear-Northeast Cape Fear and Wilmington Harbor
Project.
6) All other conditions for consistency of this project remain in effect.
2. STUDY SITES
The focus of hopper dredge overflow monitoring will occur within two channel sections of the
harbor (Upper Brunswick and Keg Island) where sand comprises less than 90 percent of the sediment
and PNAs occur adjacent to the channel. To account for any site-specific differences between these
two channel sections, monitoring events will occur in each of these two sections where overflow
dredging occurs. The PNAs occur within an area 300 yards east and west of the main shipping channel
to the shoreline. The main shipping channel is approximately 400 feet wide and 38 feet deep. Depth
of waters in the PNAs adjacent to the channel is variable but often less than 4 to 8 feet. The average
tidal range in the estuary below Wilmington is about 4 feet. Salinity of the area is variable (generally
less than 15 ppt) and often stratified, depending on river discharge and the distance from the river
mouth.
The Upper Brunswick channel range begins just south of Eagle Island at the mouth of the
Brunswick River and extends south for approximately 1.7 miles. This area is approximately 23 miles
north of the mouth of the Cape Fear River. The width of the river in this area varies between 4,000 and
9,000 feet and the open water area of this portion is approximately 600 acres. Surface sediments of
the channel are comprised of 57 percent sand and 43 percent silt and clay.
2 5 August 1998
The Keg Island channel range begins just south of the mouth of Town Creek and extends south
for approximately 2.2 miles. This area is approximately 19 miles from the mouth of the Cape Fear River.
Campbell Island (approximately 270 acres) and several small dredge spoil islands occur in this range and
the width of the river in this area is about 1.3 miles. The open water area of this portion of the river
is approximately 930 acres. Surface sediments of the channel are comprised of 63 percent sand and
37 percent silt and clay.
3. MONITORING THE EXTENT OF THE OVERFLOW PLUME
Monitoring of the sediment plume created by the hopper dredge will be conducted via collection
of aerial photographs in conjunction with concurrent observations of water quality data.
Sampling Design. Two monitoring boats using different sampling strategies (one stationary boat
and one roaming boat) will be used for obtaining water quality measurements. One stationary boat will
be positioned at the down-current edge of the plume and the other boat will collect data along transects
from the dredged area to determine the maximum extent of the lateral edge of the plume. The side of
the plume that has the greater width will be determined visually by personnel in the plane being used
for photography.
Collection of Global Positioning System (GPS) Data. GPS equipment on board each monitoring
boat and the dredge will allow accurate determinations of sampling site locations and relative positions
between monitoring boats and the dredge. Field personnel will also use portable rangefinders as a
secondary source of mapping locations. GPS positions will be differentially corrected and accurate to
within ±5 meters.
Collection of Water Quality Data. The following water quality parameters will be monitored:
1) turbidity (NTU), 2) suspended solids (mg/1), 3) salinity (ppt), 4) dissolved oxygen (mg/1), and 5)
temperature (°C). Water quality parameters will be measured to the nearest tenth (0. 1), at the edge of
the plume (2 locations), and at a background/control location. Suspended solids will be determined by
a laboratory from collected water samples. All other parameters will be measured in situ or by taking
discrete water samples and measuring the parameters with portable equipment on board the monitoring
vessel. The monitoring equipment will be EPA-approved and properly calibrated and used by experienced
personnel. The edge of the plume created by hopper dredge overflow is defined as the location where
turbidity is 25 NTUs (a range of 20 to 30 NTUs will be assumed to be at the 25 NTU boundary).
Monitoring the Downstream Edge of the Plume. The boat monitoring the down-current edge
of the plume will collect water quality measurements from three monitoring events, while anchored at
approximately 1,000 feet, 2,000 feet, and 3,000 feet from the overflowing dredge. Water quality
parameters will be monitored from a depth of 6 inches below the surface on 15-minute intervals for a
30-minute period (to include three sample times per site). Collection of water quality data will begin 5
minutes after overflow begins. The position of the dredge and dredging operations will be noted at the
time of all sample collections. The distance between the dredge and the monitoring boat will be
determined with a range finder and GPS equipment. Background water quality measurements will be
taken prior to each plume monitoring event at a location approximately 1,000 feet up-current of the
nearest dredging location.
3 5 August 1998
Monitoring the Lateral Extent of the Surface Plume. The boat monitoring the lateral extent of
the plume will collect the same water quality parameters as the down-current boat. In addition, the boat
monitoring the lateral extent will collect turbidity data from three levels in the water column (6 inches
from the surface, mid-depth, and near bottom) between the channel flanks and shore. The boat will
traverse from the center of the overflow plume toward the shore while collecting water quality data.
By recording the time and distance to the dredged area, the edge of the plume will be located and
mapped. The distance between the dredge and the monitoring boat will be determined with a range
finder and GPS equipment.
Aerial Photography. Photography will betaken from a fixed-wing aircraft using a 35-mm camera
with a polarized lens. Photographs will be taken over the center of the plume with the entire plume,
dredge, and monitoring vessels occupying the center of each photograph. Photographs will be taken
as near vertical as reasonable, but tilt control equipment is not required for the camera. Photographs
will be taken through an open window or door, not through glass or plastic.
At least three photographs (one set) will be taken in rapid succession each time a plume is
monitored. Color print film will be used with an ASA of 100. Ten 8-inch by 10-inch prints will be made
from the best negative of each set. The best negative includes a combination of least tilt and clearest
visibility of the plume. An estimated scale (to the nearest 10 feet) will be provided for each of the best
photographs. The scale will be estimated based on the known length of the hopper dredge, and by use
of the GPS and range finder data. Monitoring will not occur if conditions prevent the detection (and
photography) of a surface plume (i.e. white caps are present, surface background turbidity exceeds 20
NTUs, or sun glare or cloud shadows are present in the vicinity of the subject area).
Two sets of photographs will be taken during each of an ebb tide and flood tide (total of 4 sets).
To minimize cost and time, the two sets of photographs will be taken during the same ebb tide and flood
tide cycle. This is possible since the dredge will make several passes over the same shoal while
overflowing before going to the ocean to dispose of the dredged material. Each pass will generally last
15 to 30 minutes. The dredge will then take 10 to 30 minutes to reposition at the beginning of the
shoal and then dredge the next pass for another 10 to 30 minutes. This process is repeated (generally
2 to 3 times) until an economic load is obtained.
Photographs and water quality measurements of the plume will be taken when the plume has
reached its probable maximum extent during each pass. This should occur at the time when dredging
stops. To capture this moment, a member of the dredge crew designated by the captain will inform the
monitoring crew 5 minutes before the pass is complete. This will allow the plane and monitoring boats
time to be in position for the photographs. Personnel in the plane should be able to assist the monitoring
boats by describing the position of the visible edge of the plume. To assist with data interpretation, the
time will be recorded with each set of photographs and during the period of water quality observations.
4. MONITORING THE EXTENT AND THICKNESS OF PLUME DEPOSITION IN THE PRIMARY
NURSERY AREAS
A review of available methods to measure narrow layers of sediment deposition in a dynamic
aquatic environment resulted in the selection of sediment profile imaging (SPI) technology. Traditional
aquatic sediment traps lack accurate resolution in environments with variable currents, can be easily
disturbed by boat traffic, require more field equipment and careful deployment, and often require data
collection over a longer period in order to characterize background conditions (Gardner 1980, Baker et
al. 1988, Rosa et al. 1994). SPI is the most efficient technology for measuring thin layers of recently
deposited sediment from dredging operations because many sites can be accurately sampled within a
narrow time period (Diaz 1990).
4 5 August 1998
Sediment profile cameras have been used since the 1970s to collect data on sediments at and
below the sediment-water interface. The in situ view of surface sediments that SPI cameras photograph
allows measurement of layers to millimeter (mm) accuracy. Recently deposited dredged material is often
detected as a thin layer with different color tones and texture when compared to undisturbed natural
sediments. Nichols et al. (1990) demonstrated how effective SPI techniques could be in detecting thin
layers of sediment deposited from hopper dredge overflow. SPI is also effective for mapping the
distribution of thin layers of dredged material from open-water disposal operations [(For example: Mobile
Bay, Diaz and Schaffner (1988); Mississippi Sound, Diaz et al. (1987); Long Island Sound, Morton et
al. (1985)].
The most reliable approach to monitoring thin layers of sediment deposited from hopper dredge
overflow would be to sample during overflow operations or immediately after (within 48 hours). This
approach would assure detection of the thinnest layers of dredged material. Previous work has indicated
that layers less than 1 or 2 cm are quickly reworked by storms or infauna (Nichols et al. 1990).
Sampling Design. The short-term distribution of deposited material will be characterized by
sampling with the SPI within 48 hours of the end of overflow dredging operations. The most effective
field design for tracking thin layers of dredged material from overflow would be transects radiating away
from the hopper dredge. Transects will be located in the vicinity of transects to be established for
benthic macroinvertebrate collections (see Section 5). Transects will start close to the dredged channel
and progress perpendicular from the channel toward shallow water or the shore line. SPI samples will
be collected at intervals of about 100 to 200 feet and will be located near sites for benthic
macroinvertebrate collections. The length of the transects will be sufficient to insure that samples are
being collected to a point where no overflow dredged material is observed, or to where the water
becomes too shallow for safe operation of the deployment vessel.
The video camera in the sediment profile camera prism will be monitored from the vessel to give
a real-time estimate of the presence/absence of recently deposited layers. The end of the transects will
be used to characterize areas with no dredged material deposition (i.e. reference conditions). In the
event that the perpendicular transects will not run far enough to avoid the influence of the overflow
deposition, specific reference transects will be located up-current and down-current of the dredging
operation.
The number of stations per transect will vary depending on the length of the transect. A typical
transect will have 10 to 20 sampling stations. Five to six transects should be sufficient to characterize
overflow deposition from one dredging location. This design will allow approximately 80 to100 sampling
stations to be collected in a day.
At each station, the sediment profile camera will be deployed one time. During the entire
deployment, a video image can be observed from the vessel and will also be recorded for reevaluation
of conditions if needed to support the SPI analysis. The photographic camera will be set to photograph
the sediment surface twice on each deployment, at 4 and 14 seconds after bottom contact. This timing
sequence will allow the camera to capture the sediment water interface even in very soft sediments.
Fujichrome 100 slide film will be used. Further details on SPI camera operation can be found in Diaz
(1990).
Analytical Procedures. The analysis of stations for the presence of recently deposited thin-layers
of dredged material will be accomplished by:
5 August 1998
1) A digital video camera attached to the profile camera prism which displays the same view of the
sediment profile as the 35-mm film camera. The video signal will be sent to the surface via cable so
penetration of the prism, benthic habitat type, and the presence/absence of thin layers can be monitored.
The initial evaluation will be done on the boat in real-time or between stations by an experienced senior
scientist. The video signal will also be recorded for later detailed evaluation and review.
2) Post-field analysis will continue with the processing of the 35-mm film and a reevaluation of the
video taped data if needed. After the film is processed (within 48 hours of completion of the field
work), a visual analysis including the same parameters as estimated from the video SPI will be
conducted. These data will be combined with the video data and the final analysis will be completed
within 48 hours of film development. The combination of real-time video and high resolution image
captured on film will insure accurate and reliable collection of SPI data.
3) Data from the analysis that will be tabulated and evaluated for thin-layers of dredged material and
general benthic habitat characteristics include:
a) sediment grain size;
b) sediment layering, thickness, and type;
c) surface and subsurface fauna and structures;
d) approximate prism penetration;
e) approximate surface relief; and
f) approximate redox potential discontinuity layer.
Data to be logged at each station while in the field will include: station position, date, time,
camera counter number, depth of prism penetration as determined from the deployment frame, water
depth, and other parameters. Each developed slide will be labeled with a station identification number
that will correspond to collected data. The distribution and thickness of overflow material deposition
will be detailed in the final written report.
Quality Assurance/Quality Control Plan. Quality assurance and control for the analysis and
collection of sediment profile film images (slides/prints) will be conducted at two levels.
1) Field photographic collection of SPI images: Prior to every field deployment, all essential items will
be collected and tested for proper operation. Once the SPI system is assembled on board the research
vessel, a system check will be initiated that includes all features of the SPI system, from tightening all
bolts to testing the profile camera.
After every station or replicate deployment, the film counter will be checked to insure proper
system functioning. Any misfires or improper camera operation could then be corrected while on
station. Almost any electronic or mechanical failure of the profile camera could be repaired in the field.
Spare parts and a complete back-up camera will be available if needed.
2) Film development: Film will be developed only by established and reputable labs. Even with the
most careful control on film development, there is often variation in either the film or processing that
can create subtle color differences. To correct for this potential problem, the first and last pictures
taken each field-day will be a standard color card (Macbeth ColorcheckerTM) with red, green, blue,
white, and neutral gray densities. From these color card images any variation in color from day to day
or film to film can be detected. Color variations can then be accounted for in the computer image
analysis.
6 5 August 1998
dredging sample will be required. If the overflow plume (turbidity levels higher than background levels)
is observed in the PNAs during monitoring and deposition (2:2 cm) of dredged material is documented
in the PNAs, benthic macroinvertebrates collected from the stations before and after the dredging event
will be sieved through a 0.5 mm mesh screen, sorted, counted, and identified to the lowest possible
taxon.
The location of sampling stations will be determined upon review of the specific sites to be
dredged when that information becomes available. The level of effort will be comparable to sampling
at least 24 stations in the vicinity of a dredging location. For example, if the dredged channel is oriented
north/south, then six stations will be located in each of the four directional quadrants (NE, SE, SW, NW).
Each quadrant will have two transects oriented east/ west (from the edge of the PNA to the shore).
Each transect will have three stations within the primary nursery area spaced between the edge of the
PNA and shore. Locations of sampling stations will be recorded using differentially corrected GPS
positions. Collection of benthic macroinvertebrates will occur within two weeks prior to dredging and
two weeks after completion of dredging at a particular site, if required.
Analytical Procedures. Species will be clumped into functional guilds (based on living position
-.--' t_--?:-- `_-I n__i..--- _t -..:IJ- ..c.,... ,J„a....s .....:r., r... A. +k, + -- -+ he cneilw nhenniatl
Quality assurance and quality control for the analysis and collection of sediment profile video
recording will also be conducted at two levels.
1) Field photographic collection of video SPI images: Prior to every field deployment, all video
components will be collected and tested for proper operation. Once the video SPI system is assembled
on board the research vessel, a system check will be initiated that includes all features of the video SPI
system from tightening all bolts and video cable connectors to testing the video camera, and deck video
monitor, and recorder.
Prior to and after every station deployment, a station card will be placed in front of the prism
and recorded for 5 to 10 seconds. This will put the station data on the video tape for later analysis.
Proper system functioning (penetration of prism, flash from film SPI camera) will be monitored in real
time on deck via the video monitor. Any misfires or improper film camera operation can then be
corrected while on station. Almost any electronic or mechanical failure of the video camera can be
repaired in the field. Spare parts and a complete back-up video camera will be available if needed.
2) Video recording: The real-time video image will be monitored on deck and recorded onto Hi8 mm
tape. To check for subtle color differences due to lighting variation (prism video lights and ambient
light), a standard color card (Macbeth ColorcheckerTM) with red, green, blue, white, and neutral gray
densities will be placed in front of the prism and recorded for 5 to 10 seconds in between each station.
From these color card images, any variation in colors can be detected and can then be accounted for
in the computer image analysis.
5. MONITORING OF BENTHIC ORGANISMS
If the overflow plume (turbidity levels higher than background levels) is observed in the PNAs
and deposition (2o2 cm) of dredged material is documented in the PNAs, benthic macroinvertebrates will
be evaluated to determine the potential impacts of overflow material deposition to biological organisms.
Previous work has indicated that dredged material deposits less than 1 or 2 cm are quickly reworked by
storms or infauna and often become difficult to detect after 48 hours of deposition (Nichols et al. 1990).
Benthic macroinvertebrates are useful biological monitors because they are less mobile than other
biological organisms, are easily collected, and provide a means of estimating the potential trophic
support for fisheries resources.
Shallow subtidal areas in the Cape Fear River are subject to frequent disturbances associated
with storms, tides, flooding events, siltation, and ship traffic. Estuarine environments are often
dominated by opportunistic, resilient, benthic macroinvertebrate species that can tolerate sediment
movement (Grant 1983, Dauer 1984, Levin 1984). Major disturbances from sediment deposition (i.e.
dredging, siltation) can alter infauna communities, but these impacts are often short term. Nichols et
al. (1990) found deposition from hopper dredging operations in the Chesapeake Bay to have little effect
on benthic communities despite elevated suspended sediment concentrations and the redeposition of
sediments up to 19 cm thick. The lack of adverse impacts to benthic macroinvertebrates from
deposition of dredged material in the Chesapeake Bay was attributed to 1) non-contaminated dredged
material, 2) grain size of the dredged material was similar to natural background sediments, 3) the low
rate of deposition of new material, and 4) the species characterizing the environment were generally
short-lived, exhibited flexible life histories, and had relatively high motilities which enabled them to
withstand the sediment deposition (Nichols et al. 1990).
Sampling Design. Benthic macroinvertebrates will be sampled and analyzed where appropriate,
following the DWQ's Standard Operating Procedures Biological Monitoring (1995). Quantitative benthic
samples will be collected with a standard Ponar grab. Three replicate samples will be taken at each
station. Samples will be preserved in 10 percent formalin and retained until it is determined if a post-
7 5 August 1998
6.0 REFERENCES
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under varying flow conditions. Journal of Marine Research. 46:573-592.
Dauer, D. M. 1984. High resilience to disturbance of an estuarine polychaete community. Bulletin of
Marine Science. 34:170-174.
Diaz, R. J. 1990. Use of Sediment Profile Cameras for Dredge Material Disposal Monitoring.
Unpublished report to Waterways Experiment Station, Environmental Laboratory, U.S. Army Corps of
Engineers, Vicksburg, MS.
Diaz, R. J. and L. C. Schaffner. 1988. Monitoring environmental impacts associated with open-water
thin-layer disposal of dredged material at Fowl River, Alabama, using sediment profile camera. VIMS,
College of William and Mary, Gloucester Pt., VA. Final Rpt. to TAI Environmental Sciences, Mobile, AL.
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open-water thin-layer disposal area. Twenty week post-disposal survey, cruise 4, May 17, 1987. SAIC,
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Grant, J. 1983. The relative magnitude of biological and physical sediment reworking in an intertidal
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Levin, L. A. 1984. Life history and dispersal patterns in a dense infaunal polychaete assemblage:
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Division Corps Engr., Waltham, MA. (4 volumes).
North Carolina Department of Environment, Health and Natural Resources. Division of Environmental
Management. Water Quality Section. 1995. Standard Operating Procedures Biological Monitoring.
Environmental Sciences Branch. Ecosystems Analysis Unit. Biological Assessment Group. 37pp.
Nichols, M. M., R. J. Diaz and L. C. Schaffner. 1990. Effects of hopper dredging and sediment
dispersion, Chesapeake Bay. Envirn. Geol. Water Sci. 15:31-43.
Posey, M., W. Lindberg, T. Alphin and F. Vose. 1996. Influence of storm distribution on an offshore
benthic community. Bulletin of Marine Science. 59(3):523-529.
Rosa, F., J. Bloesch and D. E. Rathke. 1994. Sampling the settling and suspended particulate matter.
in Handbook of Techniques for Aquatic Sediment Sampling. Edited by A. Mudroch and S. D. Mac Knight.
CRC Press, Inc.
U.S. Army Corps of Engineers. Wilmington District. 1997. Use of hopper dredge with overflow as an
additional maintenance dredging method for portions of Wilmington Harbor, North Carolina.
Environmental Assessment. 1 7pp.
U.S. Army Corps of Engineers. Wilmington District. 1997. Use of hopper dredge with overflow as an
additional maintenance dredging method for portions of Wilmington Harbor, North Carolina. Finding of
No Significant Impact. 11 pp.
9 5 August 1998
ENVIRONMENTAL ASSESSMENT
USE OF HOPPER DREDGE WITH OVERFLOW
AS AN ADDITIONAL MAINTENANCE DREDGING METHOD FOR
PORTIONS OF WILMINGTON HARBOR, NORTH CAROLINA
TABLE OF CONTENTS
Heading Page No.
1.00 PROJECT DESCRIPTION ...........................................................................1
2.00 PURPOSE AND NEED ................................................................................2
3.00 ALTERNATIVE DREDGING AND DISPOSAL METHODS ..........................2
3.01 FEIS Maintenance Methods ..............................................................2
3.02 Additional Hopper Dredge Maintenance Alternative .........................3
3.03 Additional Disposal Areas .................................................................4
4.00 ENVIRONMENTAL EFFECTS .....................................................................4
4.01 Water Quality ....................................................................................5
4.02 Aquatic Resources ............................................................................7
4.03 Endangered Species .........................................................................7
4.04 Ocean Disposal of Dredged Material ................................................8
5.00 COORDINATION .........................................................................................8
6.00 CONSISTENCY DETERMINATION FOR NC COASTAL MANAGEMENT
PROGRAM ...............................................................................................9
7.00 LIST OF RECIPIENTS .................................................................................9
8.00 POINT OF CONTACT ..................................................................................9
9.00 ENVIRONMENTAL COMMITMENTS ...........................................................9
10.00 REFERENCES ...........................................................................................9
11.00 FINDING ..................................................................................................10
TABLE OF CONTENTS (Cont'd)
Table
LIST OF TABLES
Page No.
1 Hopper Dredge MCFARLAND Efficiency With and Without
Overflow ..........................................................................................11
2 Characteristics of Surface Sediments in the Wilmington Harbor,
North Carolina, Channels ................................................................12
3 Hopper Dredge Overflow of Lower Midnight Channel Sediments,
Wilmington Harbor, North Carolina .................................................13
4 Hopper Dredge Overflow of MOTSU Sediments, Wilmington
Harbor, North Carolina ....................................................................14
LIST OF FIGURES
Figure Page No.
1 Hopper Dredging Wilmington Harbor, North Carolina .........................15
2 Hopper Dredge Overflow of Lower Midnight Channel Sediments,
Wilmington Harbor, North Carolina .................................................16
3 Hopper Dredge Overflow of MOTSU Sediments, Wilmington
Harbor, North Carolina ....................................................................17
ATTACHMENTS
ATTACHMENT 1: Evaluation of Section 404(b)(1) Guidelines.
ENVIRONMENTAL ASSESSMENT
USE OF HOPPER DREDGE WITH OVERFLOW
AS AN ADDITIONAL MAINTENANCE DREDGING METHOD FOR
PORTIONS OF WILMINGTON HARBOR, NORTH CAROLINA
July 1997
1.00 PROJECT DESCRIPTION
Wilmington Harbor is an approximately 38-mile Federal navigation project
located along the Cape Fear and Northeast Cape Fear Rivers in southeastern
North Carolina (Figure 1). In the Cape Fear River below the mouth of the
Brunswick River, the Wilmington Harbor Federal Channel is 400 feet wide by 38
feet deep. Maintenance dredging in Wilmington Harbor using a hopper dredge
is currently allowed from Lower Big Island Channel downstream (Figure 1), but
in the river overflow is only allowed in areas that are generally greater than 95
percent sand (but at least 90 percent). Excluded from overflow are 7.9 miles of
the following channels (less than 90 percent sand): Keg Island, Lower Lilliput
and Lower and Upper Midnight. The proposed action would involve hopper
dredging with overflow in all these reaches. In addition, the use of hopper
dredging with overflow is proposed to extend 2.9 miles upstream from Lower Big
Island Channel to the mouth of the Brunswick River. This extension contains
Upper Big Island and Lower and Upper Brunswick Channels, which are mostly
greater than 90 percent sand. Including this 2.9-mile extension and 7.9-mile
length indicated above, a total of 10.8 miles of channel would be added to
hopper dredging with overflow maintenance method. All disposal would be in
the Wilmington Ocean Dredged Material Disposal Site (ODMDS) located beyond
3 miles offshore of the mouth of the Cape Fear River [in accordance with Section
103 of the Marine Protection Research and Sanctuaries Act of 1972, as
amended (MPRSA 1972)].
Currently, maintenance in the Wilmington Harbor Project from Lower Big
Island Channel downstream is usually performed by a bucket and barge dredge
with disposal in the ODMDS and from Upper Big Island upstream maintenance is
performed by a hydraulic pipeline dredge with disposal in the Eagle Island diked
upland disposal facility (Figure 1). However in the winter of 1997, the Corps of
Engineers hopper dredge MCFARLAND did some maintenance work in the
harbor with disposal in the ODMDS. The MCFARLAND performed some
overflow activity in March 27, 1997, as described in section 4.
The 10.8 miles of channels where hopper dredging and/or overflow is
proposed for the first time are currently maintained and are anticipated to be
maintained on a 2-4 year frequency. The average annual volume to be removed
from these channels is about 320,000 cubic yards.
2.00 PURPOSE AND NEED
The purpose of this environmental assessment (EA) is to discuss the need for
and impacts of using a hopper dredge with overflow as an additional
maintenance method for Wilmington Harbor downstream of the mouth of the
Brunswick River. This EA is also intended to amend the Final Environmental
Impact Statement (FEIS) for the Long-Term Maintenance of Wilmington Harbor
North Carolina (USACE 1989) and, the Final Feasibility Report and
Environmental Impact Statement on Improvement of Navigation Cape Fear-
Northeast Cape Fear Rivers Comprehensive Study Wilmington North Carolina
(USACE 1996) to include this maintenance method.
The reasons hopper dredging with overflow in the proposed area are
needed in addition to the other methods indicated in the FEISs are:
a. Bucket and barge dredging methods are not efficient, hydraulic
pipeline dredging methods lack sufficient disposal capacity in the middle harbor,
and disposal areas may not be available during emergencies.
b. Hopper dredging with overflow is more efficient than hopper dredging
without overflow.
c. Hopper dredging with overflow should not adversely impact the
environment.
3.00 ALTERNATIVE DREDGING AND DISPOSAL METHODS
According to USACE 1989 and 1996, several maintenance dredging and
disposal methods are allowed from the mouth of the Brunswick River
downstream. These methods are described below plus the proposed additional
hopper dredge maintenance alternative.
3.01 FEIS Maintenance Methods.
Hydraulic pipeline dredging with disposal in Eagle Island or in the
disposal islands adjacent to the ship channel. Disposal in Eagle Island
2
(Figure 1) using a hydraulic pipeline dredge is still planned from the Upper Big
Island Channel northward. However, there may be occasions when dike repair
or other activities are needed to Eagle Island, and maintenance is urgently
needed in the nearby ship channels. In such situations, Eagle Island would not
be available for a hydraulic pipeline dredge.
1P Downstream of the mouth of the Brunswick River, -the use of a hydraulic
pipeline dredge with disposal in diked disposal islands adjacent to the channel is
no longer a viable option. All these islands are essentially full and would only be
occasionally available for small volumes of dredged materials. Raising the dikes
substantially is not feasible because the dikes are currently eroding, the islands
are too small, or the dike foundations are unsatisfactory. Expansion of these
islands into the estuary is not a viable option due to the associated adverse
environmental impacts (USACE 1989).
Bucket and barge dredging with disposal in the ODMDS from Lower
Big Island Channel downstream through Lower Swash Channel. This
method has not proven efficient in maintenance dredging. Thin shoals over a
substantial area are a particular problem for bucket and barge dredging
methods. The bucket excavates the bottom unevenly, leaving ridges between
bucket grabs. These ridges are difficult to level and according to surveys, the
uneven bottom may lead to increased shoaling rates.
Hopper dredging with disposal in the ODMDS from Lower Big Island
Channel downstream through Baldhead Shoal Channel. Overflow of water
from the hopper to allow efficient loading was addressed for the Baldhead Shoal
Channel and areas where the sediments are at least greater than 90 percent
sand. From the Lower Big Island Channel to Lower Midnight Channel, overflow
is only allowed in the Upper Lilliput Channel since it contains greater than 90
percent sand.
3.02 Additional Hopper Dredge Maintenance Alternative.
Hopper dredging with overflow in all channels downstream of the
mouth of the Brunswick River would be a valuable additional maintenance
dredging method. For example, the hopper dredge MCFARLAND can hold
about twice as much sediment if the dredge was allowed to overflow water to
obtain an economic load (Table 1).
As indicated above, in the upper harbor (around river mile 20 upstream to
the mouth of the Brunswick River, Figure 1), maintenance dredging is usually
performed with a hydraulic pipeline dredge with disposal in the Eagle Island
3
diked upland facility. Therefore, the use of a hopper dredge in this area will be
rare. Probably the only time hopper dredging would be used in the upper harbor
is if emergency dike repair work in Eagle Island would temporarily preclude its
use as a disposal area (has not occurred to date), or a shoal needed to be
removed and a hydraulic pipeline or bucket and barge dredge was not available.
In 1995, emergency approval was obtained to us a bucket and barge dredge to
remove a 60,000 cubic yards shoal in the Lower Brunswick Channel. A bucket
and barge dredge was used because one was already in the harbor performing
maintenance dredging.
From the upper harbor without overflow from a hopper dredge, the
average volume dredged per cycle hour is about 225 cubic yards (Table 1).
However if overflow is permitted, the average volume dredged per cycle hour is
about 350 cubic yards. Thus with overflow the dredge would be in upper section
of the harbor about 36 percent fewer days, and reduced dredging time would
mean lower costs and reduced environmental effects.
For the middle section of the harbor (around river mile 10-15, Figure 1)
where the disposal islands are full, without overflow, the average volume
dredged per cycle hour is about 275 cubic yards (Table 1). However if overflow
is permitted, the average volume dredged per cycle hour is about 409 cubic
yards. Thus with overflow the dredge would be in middle section of the harbor
about 33 percent fewer days, and as indicated above reduced dredging time
would mean lower costs and reduced environmental effects.
3.03 Additional Disposal Areas.
Additional disposal areas for use by a hydraulic pipeline dredge are being
investigated through the preparation of a Dredged Material Management Plan
(DMMP) for the harbor. If this plan identifies additional disposal area(s) for
hydraulic pipeline dredges in the harbor, such areas would not be ready for use
until about 2001. Therefore, hopper dredging with overflow from the mouth of
the Brunswick River downstream is needed for an alternative maintenance
method for the next several years.
4.00 ENVIRONMENTAL EFFECTS
The Wilmington Harbor environment is discussed in detail in the following three
FEISs. This EA will only add information concerning the monitoring data
collected March 27, 1997, during the test overflow of the hopper dredge
MCFARLAND:
4
a. Final Environmental Impact Statement, Long-Term Maintenance of
Wilmington Harbor, North Carolina (USACE 1989).
b. Final Feasibility Report and Environmental Impact Statement, on
Improvement of Navigation, Cape Fear-Northeast Cape Fear Rivers
Comprehensive Study, Wilmington, North Carolina (USACE 1996).
c. Final Environmental Impact Statement, Savannah, Georgia;
Charleston, South Carolina; and Wilmington, North Carolina, Ocean Dredged
Material Disposal Site Designation. (USEPA 1983).
4.01 Water Quality.
Two overflow events from the MCFARLAND were monitored in the middle
section of the harbor where the hopper dredge was working on March 27, 1997.
The first discussed here is the results of overflow monitoring on the dredged
material from Lower Midnight Channel (LMC). The sediments in LMC are about
76 percent sand and are generally representative of the channels below the
mouth of the Brunswick River where overflow is currently not allowed (Table 2).
Table 3 indicates a major reduction in suspended sediment concentration and
turbidity with distance from the dredge. Both parameters neared background
values at 3,300 feet from the dredge. Other measured water quality parameters
(temperature, salinity, and dissolved oxygen), remained relatively constant. The
suspended sediment data for LMC are graphed on Figure 2 along with the
estimated values from a study conducted in the Chesapeake Bay (Nichols et. al
1990). The percent sand in the Chesapeake Bay sediments were less than 20
percent and only data for mid-depth were available. The background and
hopper dredge overflow weir suspended sediments are also plotted on Figure 2.
This figure indicates that the concentrations of suspended sediments are lower
for LMC for all locations compared to Chesapeake Bay and the LMC levels
approach the background concentrations at a shorter distance. The major
difference between the LMC and Chesapeake concentrations is probably due to
the higher percentage of sand in the LMC sediments.
The North Carolina Division of Water Quality (NCDWQ) standard for
turbidity for saltwater is 25 NTU's. There is no NCDWQ suspended sediment
standard for the Cape Fear River. The surface and mid-depth background
turbidity values measured March 27, 1997, were both below 25 NTUs (16.0 and
14.3, respectively) whereas the bottom value was slightly above the standard
(28.5) probably due to turbulence caused by river currents (about 2.0 knots)
moving across the sediments. At 1,600 feet from the dredge during the overflow
test, the surface value returned to below 25 NTUs and at 3,300 the mid-depth
value returned to below standard (Table 3). The bottom value was only slightly
higher than the background value (30.2 vs. a background of 28.5 NTUs) at 3,300
5
feet. This turbidity plume is confined between the dredge and 3,300 feet since
the dredge is steering into the river currents averaging about 2.0 knots. The
lateral extend of the plume was not measured in this test, but the plume should
be confined principally to the 400-foot-wide channel limits since the current
follows the channel alignments. In the Chesapeake Bay study even though the
sediments there were less than 20 percent sand, of the dredged material in the
overflow, "less-than 1 percent drifts beyond the channel environs" (Nichols et. al
1990).
The second overflow monitoring was on the dredged material from Military
Ocean Terminal, Sunny Point (MOTSU, Table 4). MOTSU is not a part of the
Wilmington Harbor ship channel but overflow of the hopper from sediments
dredged from MOTSU should represent a worst-case scenario for suspended
sediments and turbidity since the MOTSU sediments in the area dredged are
about 35 percent sand (65 percent silt and clay). The lowest percentage sand in
the Wilmington Harbor channels to be dredged is 53.5 percent (46.5 percent silt
and clay, Table 2). Table 4 indicates a major reduction in suspended sediment
concentration and turbidity with distance from the dredge with both parameters
approaching background values at 1,600 feet from the dredge. Time did not
permit measurements at 3,300 feet from the dredge, but it is anticipated that
near background levels would also be reached at that distance. The rest of the
parameters remained relatively constant. The suspended sediment data for
MOTSU is graphed on Figure 3 along with the estimated values from the
Chesapeake Bay Study (Nichols et. al 1990). As indicated above, the percent
sand in the Chesapeake Bay sediments were less than 20 percent and only data
for mid-depth were available. The background and hopper dredge overflow weir
suspended sediments are also plotted (Figure 3). This figure indicates that the
concentrations of suspended sediments are lower for MOTSU for all locations
compared to Chesapeake Bay and the MOTSU levels approach the background
concentrations at a shorter distance. As indicated for the LMC sediments, the
major difference between the MOTSU and Chesapeake concentrations is
probably due to the higher percentage of sand in the MOTSU sediments.
As with the LMC test, at 1,600 feet from the dredge during the overflow
test, the surface value for turbidity returned to below the NCDWQ standard of 25
NTU's. Measurements were not taken at 3,300 feet due to time restraints, but it
is anticipated that the mid-depth and bottom values would be below or near the
standard as was the case for the LMC test.
The North Carolina Division of Environmental Management will
concurrently review this EA and the Corps' request for a Section 401 (P.L. 95-
217) Water Quality Certificate to authorize the work that may impact water
quality under the proposed action. Also, the Section 404(b)(1) evaluation for the
discharge of dredged material is included in Attachment A.
6
4.02 Aquatic Resources.
The only change to resources from the Wilmington Harbor FEISs is the
increased turbidity and suspended solids levels associated with overflow of the
hopper dredge. Without overflow, turbidity/suspended solids (TSS) is confined
to the near bottom zone from agitation associated with the hopper draghead.
This agitation occurs for the 13 minutes of dredging during a each dredging
cycle, or an average of about 0.6-0.7 hours per day (Table 1). With overflow,
increased TSS levels would occur about 1.12 hours during each dredging cycle
or an average of about 3-4 hours per day.
The proposed action should also have minimal impact on other aquatic
resources. With or without overflow, the hopper dredge would be dredging
sediment the same number of total hours during the North Carolina Division of
Marine Fisheries dredging window (August 1 to January 31). However since
overflow is more efficient (more volume per cycle hour, Table 1), the dredge
would be in the harbor 33-36 percent fewer days. Hopper dredging with
overflow will be confined to the Wilmington Harbor ship channel from the mouth
of the Brunswick River downstream. In this area, primary nursery areas (PNA)
for marine fisheries are not within 300 yards either side of the center line of the
channel, and as indicated above, the TSS plume is expected to remain within
the channel.
4.03 Endangered Species.
Endangered species issues were addressed through the EIS process
associated with the 1989 and 1996 FEISs (USACE 1989 and 1996) for
Wilmington Harbor. In the area where hopper dredging is currently allowed
(Lower Big Island downstream), the only change from the FEISs would be that
overflow would be performed in about 7.9 more miles of channel. The TSS
associated with the overflow should not impact any of the endangered species
(sea turtles, shortnose sturgeon and manatee) in the Harbor. The sea turtles
and manatee breathe air and the shortnose sturgeon is highly mobile and can
avoid the dredge. Overflow should reduce potential impacts since the dredge
would be in the harbor about 1 /3 fewer days. Also, overflow will essentially
double each load (1,230 vs. 2,400 cubic yards, Table 1) in the hopper, resulting
in the number of round trips to the ODMDS being reduced by about half. This
will reduce the potential for interaction with list species.
As indicated above, using a hopper dredge to maintain the upper harbor
would be a rare since this portion of the harbor is routinely maintained with a
hydraulic pipeline dredge with disposal in Eagle Island.
7
The use of a hopper dredge will be in accordance with the National
Marine Fisheries Service regional biological opinion dated April 9, 1997, and
August 25, 1995 (NMFS 1997, 1995).
Based on the above, the proposed action is not anticipated to adversely
effect endangered species.
4.04 Ocean Disposal of Dredged Material.
Only dredged materials which have been evaluated in accordance with
EPA's Ocean Dumping Regulations and Criteria (40 CFR 220-229) and found
acceptable may be transported for disposal in the Wilmington ODMDS under
section 103 of MPRSA 1972. Wilmington Harbor channel sediments from Lower
Big Island Channel downstream to Baldhead Shoal channel may currently be
transported for ocean disposal. A Section 103 evaluation of Wilmington Harbor
Channel sediments from the Anchorage Basin through Baldhead Shoal Channel
has been accomplished. This evaluation includes all channels where hopper
dredging with overflow is proposed. The evaluation is being submitted to EPA
Region IV for concurrence.
5.00 COORDINATION
Representatives from the agencies listed below were contacted regarding the
proposed action and preparation of the EA. Representatives from these
agencies were involved in one or both of the March 1997 field trips regarding
overflow from the MCFARLAND hopper dredge in Wilmington Harbor. The
purpose of the March 7, 1997, trip was to familiarize the agencies with the
operations of a hopper dredge. The purpose of the
March 27, 1997, trip was to monitor the overflow of the hopper dredge.
NC Division of Coastal Management
NC Division of Environmental Quality
NC Division of Marine Fisheries
NC Wildlife Resources Commission
U.S. Fish and Wildlife Service
National Marine Fisheries Service
Agencies contacted but not able to attend the field trips:
U.S. Environmental Protection Agency
8
6.00 CONSISTENCY DETERMINATION FOR NC COASTAL MANAGEMENT
PROGRAM
Based on the information presented above, the proposed action is consistent
with the Coastal Management Program of the State of North Carolina.
7.00 LIST OF RECIPIENTS
The list of recipients is the same as indicated on pages EIS-74 to EIS-76 of
USACE 1996.
8.00 POINT OF CONTACT
Any comments or questions regarding this EA should be addressed to Mr. Frank
Yelverton, Environmental Resources Section, U.S. Army Corps of Engineers,
Wilmington District, PO Box 1890, Wilmington, North Carolina 28402-1890.
Telephone contact is 910-251-4640.
9.00 ENVIRONMENTAL COMMITMENTS
Hopper dredging in the new areas proposed for overflow will be conducted
during the NCDMF dredging window (August 1 - January 31) and in accordance
with the National Marine Fisheries Service Biological Opinions for hopper
dredging (NMFS 1995 and 1997).
10.00 REFERENCES
National Marine Fisheries Service. 1997. Interim Biological Opinion, U.S. Army
Corps of Engineers, South Atlantic Division. The continued hopper dredging of
two channels and one borrow area in the southeastern United States during
1997.
National Marine Fisheries Service. 1995. Biological Opinion, U.S. Army Corps
of Engineers, South Atlantic Division. The hopper dredging of channels and
beach nourishment activities in the Southeastern United States from North
Carolina through Florida East Coast.
Nichols, M., R.J. Diaz and L.C. Schaffner. 1990. Effects of Hopper Dredging
and Sediment Dispersion, Chesapeake Bay. Environ. Geol. Water Sci. Vol. 15,
No. 1. 31-43.
9
U.S. Army Corps of Engineers, Wilmington District. 1989. Final Environmental
Impact Statement, Long-Term Maintenance of Wilmington Harbor, North
Carolina, Wilmington, NC, October 1989.
U.S. Army Corps of Engineers, Wilmington District. 1996. Final Feasibility
Report and Environmental Impact Statement, on Improvement of Navigation,
Cape Fear-Northeast Cape Fear Rivers Comprehensive Study, Wilmington,
North Carolina, Wilmington, NC, June 1996.
U.S. Environmental Protection Agency. 1983. Final Environmental Impact
Statement, Savannah, Georgia; Charleston, South Carolina; and Wilmington,
North Carolina, Ocean Dredged Material Disposal Site Designation. October
1983.
11.00 FINDING
The proposed action should not significantly affect the quality of the human
environment; therefore, an Environmental Impact Statement will probably not be
required. If this opinion is upheld following circulation of this EA, a Finding of No
Significant Impact (FONSI) will be signed and circulated.
10

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TABLE 2. CHARACTERISTICS OF SURFACE SEDIMENTS IN THE WILMINGTON HARBOR, NC
CHANNELS.
Channel
Baldhead Shoal
Offshore reaches
Inside Reaches
Smith Island
Bald head-Ca swell
Southport
Battery Island
Lower Swash
Horseshoe Shoal
Reaves Point
Lower Midnight
Upper Midnight
Lower Lilliput
Upper Lilliput
Keg Island
Upper and Lower Big Island
Lower Brunswick
Upper Brunswick
Fourth East Jetty and Between
Anchorage Basin
Between Memorial and
Hilton Railroad Bridges
Above Hilton Railroad Bridge
%Gravel %Sand % Silt & Clay
0.0 73.2 26.8
0.0 98.7 1.3
7.9 92.0 0.1
18.0 80.5 1.5
12.5 85.5 2.0
38.0 61.0 1.0
27.0 70.0 3.0
0.0 98.0 2.0
0.0 99.0 1.0
0.0 76.0 24.0
0.0 82.5 17.5
0.0 53.5 46.5
0.0 98.0 2.0
0.0 63.0 37.0
2.0 94.0 3.0
0.0 92.7 7.3
0.0 57.0 43.0
0.0 80.0 20.0
0.0 6.0 94.0
10.0 55.0 35.0
0.0 58.0 42.0
12
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I
SECTION 404(B)(1) (PUBLIC LAW 95-217) EVALUATION
USE OF HOPPER DREDGE WITH OVERFLOW
AS AN ADDITIONAL MAINTENANCE DREDGING METHOD
FOR PORTIONS OF WILMINGTON HARBOR
WILMINGTON, NORTH CAROLINA
Evaluation of Section 404(b)(1) Guidelines
40 CFR 230

1. Review of Compliance (230.10(a)-(d)) Preliminary 1/ Final 2/
Review of the NEPA Document indicates:
a. The discharge represents the least
environmentally damaging practicable
alternative and if in a special aquatic
site, the activity associated with the
discharge must have direct access or
proximity to, or be located in the
aquatic ecosystem to fulfill its basic
purpose (if no, see section 2 and NEPA
document);
YESI 1 N01 1* YESIXI N011
b. The activity does not: 1) violate
applicable State water quality
standards or effluent standards
prohibited under Section 307 of the
CWA; 2) jeopardize the existence of
federally listed endangered or
threatened species or their habitat;
and 3) violate requirements of any
federally designated marine sanctuary
(if no, see section 2b and check
responses from resource and water
quality certifying agencies); YESI_1 N01_1* YESIXI N01_1
C. The activity will not cause or
contribute to significant degradation
of waters of the U.S. including adverse
effects on human health, life stages of
organisms dependent on the aquatic
ecosystem, ecosystem diversity,
productivity and stability, and
recreational, aesthetic, and
economic values (if no, see section
2); YESI 1 N01 1* YESIXI N011
d. Appropriate and practicable steps have
been taken to minimize potential
adverse impacts of the discharge on
the aquatic ecosystem
(if no, see section 5).
YESI 1 N01-1* YESIXI N011
Proceed to Section 2
*, 1, 21 See page A-6
A-1
Not Signifi- Signifi-
2. Technical Evaluation Factors (Subparts C-F) N/A cant cant*

a. Physical and Chemical Characteristics
of the Aquatic Ecosystem (Subpart C)

(1) Substrate impacts. I I X I I
(2) Suspended particulates/turbidity I i I I
impacts. I I X I I
(3) Water column impacts. I I X I I
(4) Alteration of current patterns I I I I
and water circulation. I I X I I
(5) Alteration of normal water I I I I
fluctuations/hydroperiod. I I X I I
(6) Alteration of salinity I I I I
gradients. I I X I I
b. Biological Characteristics of the
Aquatic Ecosystem (Subpart D)

(1) Effect on threatened/endangered I I I I
species and their habitat. I I X I
(2) Effect on the aquatic food web. I I X I I
(3) Effect on other wildlife (mammals, I I I
birds, reptiles, and amphibians). I I X I I

C. Special Aquatic Sites (Subpart E)

(1) Sanctuaries and refuges. I X I
(2) Wetlands. I X I
(3) Mud flats. I X I
(4) Vegetated shallows. I X I I I
(5) Coral reefs. I X I I
(6) Riffle and pool complexes. I _X I I I
d. Human Use Characteristics (Subpart F)

(1) Effects on municipal and private I I I I
water supplies. I X I I I
(2) Recreational and commercial I I I I
fisheries impacts. I I X I I
(3) Effects on water-related recreation.) I X I 1
(4) Aesthetic impacts. I I X I
(5) Effects on parks, national and I I I
historical monuments, national I I I I
seashores, wilderness areas, I I I
research sites, and similar I I I
preserves. I X I I

Remarks: Where a mark is placed under
the significant category, preparer add
explanation below.
Proceed to Section 3
*See page A-6

r
A-2
3. Evaluation of Dredged or Fill Material (Subpart G) 3/
a. The following information has been
considered in evaluating the biological
availability of possible contaminants in
dredged or fill material. (Mark only
those appropriate.)
(1) Physical characteristics . . . . . . . . . . . . . . . . . .1X1
(2) Hydrography in relation to
known or anticipated _
sources of contaminants . . . . . . . . . . . . . . . . . . . 1 X 1
(3) Results from previous
testing of the material
or similar material in
the vicinity of the project . . . . . . . . . . . . . . . . . 1 X 1
(4) Known, significant sources of
persistent pesticides from _
land runoff or percolation . . . . . . . . . . . . . . . . . . 11
(5) Spill records for petroleum
products or designated
(Section 311 of CWA) _
hazardous substances . . . . . . . . . . . . . . . . . . . . . I X 1
(6) Other public records of
significant introduction of
contaminants from industries,
municipalities, or other
sources . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 X 1
(7) Known existence of substantial
material deposits of
substances which could be
released in harmful quantities
to the aquatic environment by _
man-induced discharge activities . . . . . . . . . . . . . 11
(8) Other sources (specify) . . . . . . . . . . . . . . . .. . . 11
List appropriate references.
Reference: Final Environmental Impact Statement, Cape Fear -
Northeast Cape Fear Rivers Comprehensive Study, New Hanover and
Brunswick Counties, North Carolina, June 1996.
Environmental Assessment, Use of Hopper Dredge with Overflow
as an Additional Maintenance Dredging Method for Portions of
Wilmington Harbor, North Carolina, July 1997.
b. An evaluation of the appropriate information in 3a
above indicates that there is reason to believe the
proposed dredge or fill material is not a carrier of
contaminants, or that levels of contaminants are sub-
stantively similar at extraction and disposal sites and
not likely to result in degradation of the disposal site. _
The material meets the testing exclusion criteria. YES 1X1 NO 1_1*
Proceed to Section 4
3/, see page A-6
A-3
4. Disposal Site Determinations (230.11(f)).
a. The following factors as appropriate,
have been considered in evaluating the
disposal site.
(1) Depth of water at disposal site . . . . . . . . . . . . IXI
(2) Current velocity, direction, and

variability at disposal site . . . . . . . . . . _
. . . IXI
(3) Degree of turbulence . . . . . . . . . . . . . . . . . 1 X I
A
(4) Water column stratification . . . . . . . . . . . . . . IXI
(5) Discharge vessel speed and

direction . . . . . . . . . . . . .. . . . . . . _
. . . 1 X I
(6) Rate of discharge . . . . . . . . . . . . . . . . . . . 1X1
(7) Dredged material characteristics
(constituents, amount and type _
of material, settling velocities). . . . . . . . . . . .?Xj
(8) Number of discharges per unit of _
time . . . . . . . . . . . . . . . . . . . . . . . . . I X I
(9) Other factors affecting rates and
patterns of mixing (specify)
List appropriate references.
Reference: Final Environmental Impact Statement, Ca pe Fear -
Northeast Cape Fear Rivers Comprehensive Study, New Hanover and
Brunswick Counties, North Carolina, June 1996.
Environmental Assessment, Use of Hopper Dredge with Overflow
as an Additional Maintenance Dredging Method for Por tions of
Wilmington Harbor, North Carolina, July 1997.
b. An evaluation of the appropriate factors in
4a above indicates that the disposal site

and/or size of mixing zone are acceptable . . . .YES _
1X1 NO 1_1*
5. Actions to Minimize Adverse Effects (Subpart H).

All appropriate and practicable steps have been taken,
through application of recommendations of 230.70-230.77,
to ensure minimal adverse effects of the proposed _
discharge. List actions taken. YES IXI NO 1_1*
See sections 4.01 through 4.04 and 8.00 of the environmental assessment.
Return to section 1 for final stage of compliance review. See also
note 3/, page A-6.
*See page A-6
A-4

6. Factual Determinations (230.11).
A review of appropriate information as identified in
items 2-5 above indicates that there is minimal
potential for short- or long-term environmental
effects of the proposed discharge as related to:
a. Physical substrate at the disposal site
(review sections 2a, 3, 4, and 5).
b. Water circulation, fluctuation, and salinity
(review sections 2a, 3, 4, and 5).
C. Suspended particulates/turbidity
(review sections 2a, 3, 4, and 5).
d. Contaminant availability
(review sections 2a, 3, and 4).
e. Aquatic ecosystem structure and function
(review sections 2b and c, 3, and 5).
f. Disposal site
(review sections 2, 4, and 5).
g. Cumulative impact on the aquatic
ecosystem.
h. Secondary impacts on the aquatic
ecosystem.
YES IXI NO 11*
YES IXI NO 11*
YES IXI NO 11*
YES IXI NO 11*
YES IRI NO 1-1*
YES 1XI NO 1-1*
YES IXI NO 11*
YES 1XI NO 1-1*
7. Findings.
a. The proposed disposal site for discharge of
dredged or fill material complies with the
Section 404(b)(1) guidelines . . . . . . . . . . . . . . . . .IXI
b. The proposed disposal site for discharge of
dredged or fill material complies with the
Section 404(b)(1) guidelines with the _
inclusion of the following conditions: I_I
*See page A-6
A-5
1

C. The proposed disposal site for discharge of
dredged or fill material does not comply with
the Section 404(b)(1) guidelines for the
following reasons(s):
(1) There is a less damaging practicable alternative. . . . . I I
(2) The proposed discharge will result in significant _
degradation of the aquatic ecosystem . . . . . . . . . . I I
(3) The proposed discharge does not include all
practicable and appropriate measures to minimize _
potential harm to the aquatic ecosystem . . . . . . . . . I
8
C.E.Shuford, Jr., P.E.
Acting Chief, Engineering
and Planning Division
Date:
*A negative, significant, or unknown response indicates that the permit application may
not be in compliance with the Section 404(b)(1) Guidelines.
1/ Negative responses to three or more of the compliance criteria at this stage
indicate that the proposed projects may not be evaluated using this "short form
procedure." Care should be used in assessing pertinent portions of the technical
information of items 2 a-d, before completing the final review of compliance.
2/ Negative response to one of the compliance criteria at this stage indicates that the
proposed project does not comply with the guidelines. If the economics of navigation
and anchorage of Section 404(b)(2) are to be evaluated in the decision-making process,
the "short form evaluation process is inappropriate."
3/ If the dredged or fill material cannot be excluded from individual testing, the
"short-form" evaluation process is inappropriate.
A-6
1
V

r State of North Carolina
Department of Environment,
Health and Natural Resources
Division of Coastal Management
James B. Hunt, Jr., Governor
Wayne McDevitt, Secretary
Roger N. Schecter, Director
October 6, 1997

Colonel Terry R. Youngbluth
District Engineer, Wilmington District
U.S. Army Corps of Engineers
P.O. B ox 1890
Wilmington, NC 28402-1890

Ji',i i U {?I
ENVIPM",41 nirAtSCIENCF t
REFERENCE: CD97-26 Use of Hopper Dredge with Overflow, Wilmington Harbor
Dear Colonel Youngbluth:
The State of North Carolina has completed its review of the referenced proposal for hopper
dredging with overflow in Wilmington Harbor, for consistency with the North Carolina Coastal
Management Program, pursuant to 15 CFR 930 Subpart C, Consistency for Federal Activities. The
document was received in our office September 8, 1997 and assigned the review number DCM97-38.
The Corps of Engineers is requesting authorization to use hopper dredging with overflow to maintain
two sections totaling 10.8 miles of the Cape Fear - Northeast Cape Fear River/Wilmington Harbor
Project. The sediment content in theses portions of the channel is less than 90 percent sand.
Currently, the Corps is allowed to use hopper dredge with overflow in areas where sediments are
greater than 90 percent sand. The purpose of the proposed change in maintenance method is to allow
the Corps of Engineers to achieve an "economic load" over a greater length of the channel. Based
upon our review, we cannot disagree with the Corps determination that the proposal is consistent
with the North Carolina Coastal Management, provided the following conditions are met.
1. All conditions of the 401 Water Quality Certification issued by the NC Division of Water
Quality are met. This Certification must remain active for hopper dredge with overflow to
be used within portions of the channel authorized herein.
2. The Division of Coastal Management shall be provided the opportunity to review and
comment on any monitoring plans that are implemented as prescribed by the conditions of
the 401 Water Quality Certification. The Division of Coastal Management will be provided
a copy of the results of any monitoring for review.
3. Aerial photography shall be obtained to monitor the movement and dissipation of the
sediment plume as part of the project. Aerial photography will provide valuable visual data
to complement water quality observations and or sampling. Site conditions for flight should
P.O. Box 27687, Raleigh, North Carolina 2761 1-7687 Telephone [phone]
An Equal opportunity Affirmative Action Employer 501/6 Recycled / 10% Post-Consumer Paoer
be coordinated with the Division of Water Quality and Jim Gregson of the Division of
Coastal Management (910/395-3900).
4. Discharge within the mixing zone must not result in acute toxicity to aquatic life or
prevent the free passage of aquatic organisms.
5. The Corps of Engineers will continue its efforts to develop a Dredged Material
Management Plan for the Cape Fear-Northeast Cape Fear and Wilmington Harbor Project.
6. All other conditions for consistency of this project remain in effect.
The stated purpose of the project is to allow the Corps of Engineers to achieve an "economic
load", to dredge the channel in a more economically efficient manner. While the proposed project
modification may provide economic benefit to the Corps, the impacts of hopper dredging with over
flow of finer material (< 90 % sand) on the natural resources of the coastal zone are not known. It
is known that sensitive areas, including Primary Nursery Areas, are placed at greater risk with
increased turbidity and sedimentation. Therefore, monitoring for water quality and biological
impacts associated with this project is particularly important. We are hesitant to approve projects
and project modifications for economic benefit when it cannot be shown that the work will not
adversely impact natural resources of the coastal zone.
If you have any questions regarding our finding, conditions, or recommendations, please
contact me or Mr. Steve Benton, Division of Coastal Management, at [phone]. Thank you
for your consideration of the North Carolina Coastal Management Program.
Sincerely,
Schecter
cc: Bob Stroud, Division of Coastal Management, Wilmington
John Dorney, Division of Water Quality
Preston Pate, Director, Division of Marine Fisheries
Frank Yelverton, US Army Corps of Engineers
• _...*.
State of North Carolina
Department of Environment,
Health and Natural Resources
Division of Water Quality
James B. Hunt, Jr., Governor
Wayne McDevitt, Secretary
A. Preston Howard, Jr., P.E., Director
Mr. Coleman Long
Wilmington District Corps of Engineers
Environmental Resources Section
Post Office Box 1890
Wilmington, North Carolina 28402-1890
Dear Mr. Long,
ITL.KMAI?EHNR
September 26, 1997
Re: Certification Pursuant to Section 401 of the Federal Clean Water Act,
Proposed use of hopper dredge with overflow - Wilmington Harbor dredging
WQC Project #970625
New Hanover County
Attached hereto is a copy of Certification No. 3157 issued to U.S. Army Corps of
Engineers dated September 26, 1997.
If we can be of further assistance, do not hesitate to contact us.
Sincerely,
eston Howard, Jr. .
Attachments
3157wgc
cc: Wilmington District Corps of Engineers
Corps of Engineers Wilmington, 1997 Field Office
Wilmington DWQ Regional Office
Mr. John Dorney
Mr. John Parker, Division of Coastal Management
Central Files
John Hefner, U.S. Fish and Wildlife Services
Jim Gregson, Wilmington DCM
Division of Water Quality - Environmental Sciences Branch
Enviro. Sciences Branch, 4401 Reedy Creek Rd., Raleigh, NC 27607 Telephone [phone] FAX # [phone]
An Equal Opportunity Affirmative Action Employer - 50% recycled/10% post consumer paper

NORTH CAROLINA 401 WATER QUALITY CERTIFICATION
THIS CERTIFICATION is issued in conformity with the requirements of Section
401 Public Laws 92-500 and 95-217 of the United States and subject to the North Carolina
Division of Water Quality (DWQ) Regulations in 15 NCAC 2H, Section.0500 to U.S.
Army Corps of Engineers in New Hanover County pursuant to an application filed on the
14th day of July 1997 to utilize a hopper dredge with overflow for the dredging of
Wilmington Harbor.
The application provides adequate assurance that the dredging of Cape Fear River will
not result in a violation of applicable Water Quality Standards and discharge guidelines.
Therefore, the State of North Carolina certifies that this activity will not violate the
applicable portions of Sections 301, 302, 303, 306, 307 of PL 92-500 and PL 95-217 if
conducted in accordance with the application and conditions hereinafter set forth.
This approval is only valid for the purpose and design that you submitted in your
application, as described in the Public Notice or as modified below. If you change your
project, you must notify us and you may be required to submit a revised application. For
this approval to be valid, you must follow the conditions listed below. In addition, you
should get any other federal, state or local permits before you go ahead with your project
including (but not limited to) Sediment and Erosion control, Coastal Stormwater, Non-
discharge and Water Supply watershed regulations.
Condition(s) of Certification:
1. If dredging is done in locations with less than 90% sand, water quality data shall
be collected by the U.S. Army Corps of Engineers for total suspended residue and
turbidity to determine the lateral extent of the sediment plume above background levels
into the adjacent Primary Nursery Area (PNA) as well as the extent and thickness of the
sediment redeposition on the channel flanks.
2. If the sediment plume extends above background levels into the PNA, the effect of
sediment redeposition on benthic organisms in the PNA shall be documented by the
U.S. Army Corps of Engineers by monitoring pre-and post benthic abundance and
diversity in areas adjacent to the channel in the adjacent PNA where redeposition is
observed The monitoring shall be at intervals for up to 1-1/2 years or until background
levels of benthic organisms are achieved Written approval from DWQ is required for
the monitoring plan before dredging utilizing the hopper dredge when overflow is
implemented
3. If results from the water quality and monitoring reveal significant environmental
impacts, this 401 Certification may be modified to reflect these impacts. Similarly if the
monitoring reveals a lack of environmental impact, this certification may be modified to
remove these monitoring requirements.
Violations of any condition herein set forth shall result in revocation of this
Certification and may result in criminal and/or civil penalties. This Certification shall
become null and void unless the above conditions are made conditions of the Federal 404
and/or coastal Area Management Act Permit. This Certification shall expire upon expiration
of the 404 or CAMA permit.
If this Certification is unacceptable to you you have the right to an adjudicatory hearing
upon written request within sixty (60) days following receipt of this Certification. This

27447, Raleigh, N.C. 27611-7447. If modifications are made to an original Certification,
you have the right to an adjudicatory hearing on the modifications upon written request
within sixty (60) days following receipt of the Certification. Unless such demands are
made, this Certification shall be final and binding.
WQC 3157
This the 26th day of September 1997
DIVISION OF WATER QUALITY
R. o , Jr. P.E.
State of North Carolina IT
Department of Environment, LTW;%
Health and Natural Resources 4 •
Division of Water Quality
James B. Hunt, Jr., Governor
Wayne McDevitt, Secretary
p E H N F
A. Preston Howard, Jr., P.E., Director
September 26, 1997
Mr. W. Coleman Long
Wilmington District Corps of Engineers
Environmental Resources Section
P.O. Box 1890
Wilmington, N.C. 28402-1890
SUBJECT: 401 Water Quality Certification
Hopper Dredge Overflow-Wilmington Harbor
New Hanover County
DWQ# 970625
We have carefully reviewed your August 13, 1997 reply letter
regarding the subject project and the proposed 401 Certification
conditions. Below we have provided a summary of the reasons why we
believe that this additional monitoring is necessary.
From the data collected during the trial dredging, it is
apparent that residue and turbidity approach background values 3,300
feet behind the dredge. The Division f water Quality is also aware
that the quantity of material to be dredged in Wilmington Harbor is
much less than the quantity dredged in a hopper dredge overflow
operation in Chesapeake Bay (Nichols et al. 1990). However, we are
still concerned that the lateral migration and subsequent
redeposition would adversely effect benthic assemblages in areas
adjacent to the charnel, which are classified as Primary Nursery
Areas (PNAs). Our concerns can be summarized as follows:
1) During DWQ's March 27, 1997 field visit aboard the hopper dredge
McFarland, no residue or turbidity sampling of the sediment plume was
made to determine its lateral extent beyond the channel axis.
2) Nichols et al. (1990) found that the sediment plume width
increases with age. Seven (7) minutes after the dredge passes, the
near field zone width is narrow (ca. 140 m). However, 63 minutes
after the dredge pass, the near field width of the sediment plume
increases to > 1, 100 m (Nichols et al. 1990). The PNA of concern
near the channel axis in Wilmington Harbor is only some 300 meters
away.
3) The Nichols et al. study site had a northwest current component.
The greatest extent of sediment plume propagation (other than that
from directly behind the dredge) occurred in the southwest direction.
Yet despite the northwest current, a sediment plume still extended
over 300m from the dredge track in the northeastern direction
(Nichols et al. 1990).
Environmental Sciences Branch 4401 Reedy Creek Road Raleigh, North Carolina 27607
Telephone [phone] FAX # [phone]
An Equal Opportunity Affirmative Arlon Employer 509. recycled/10% post consumer paper
1 I
I?,?I
•
US Army Corps
y.,
of Engineers
WILMINGTON DISTRICT
ENVIRONMENTAL ASSESSMENT
USE OF HOPPER DREDGE WITH OVERFLOW
AS AN ADDITIONAL MAINTENANCE DREDGING METHOD
FOR
PORTIONS OF WILMINGTON HARBOR
NORTH CAROLINA
JULY 1997
Mr. W. Coleman Long
Wilmington Corps of Engineers
Wilmington harbor Dredging
4) The overwhelming majority of studies regarding dredging have been
focused chiefly on disposal sites. There are few data pertaining to
the dispersion of suspended sediment and the impact of sediment
accumulation around dredge sites (Nichols et al. 1990). This is most
notably true for the dispersion of sediment discharged by hopper
overflow (Nichols et al. 1990). Nichols et al. (1990) goes on further
to state that a notable exception (Sustar et al. 1976) dealt with
hopper dredging in San Francisco Bay. However, the Sustar et al.
study showed that the resuspension and rate of dispersion of sediment
is dependent on the dredge and duration of water-sediment
interactions. Consequently (and importantly), the information is site
specific (Nichols et al. 1990).
5) In a literature review of recovery times for benthic communities
after dredging in Chesapeake Bay, Nichols et al. (1990) found that
the recovery times for benthic communities range from within months
to a year and a half depending on community type. Furthermore,
Nichols et al. (1990) determined that intercomparison of the data
from these studies (15 in all) is difficult and that the results are
mainly site specific. Nichols et al. (1990) continue by stating that
these studies do provide a useful first order understanding of the
range of environmental effect dredging has in Chesapeake Bay but the
environmental risks of dredging cannot be predicted with certainty
because quantitative field data are lacking.
For these reasons DWQ believes that it is reasonable to require
USACOE to undertake the additional monitoring efforts as outlined in
the attached 401 Certification. Since there was no sampling of the
sediment plume laterally during the hopper overflow, and the Nichols
et al. study demonstrated lateral flow and deposition with this type
of dredging, there is no evidence that sediment will remain in the
400 foot wide channel limits. Considering the aforementioned points
DWQ believes that the monitoring is justified to protect water
quality standards and the nearby PNAs.
If you should have any questions regarding the content of this
letter please feel free to call me at [phone].
S' cep
J n R. Dorney
W er Quality 6.. ication Program
Cc: Frank Yelverton, USACOE-Wilmington District Office
John Parker, N.C. Division of Coastal Management
Rick Shiver, DWQ-Wilmington Regional office
State of North Carolina
Department of Environment,
Health and Natural Resources
JamesEk Hunt, Jr., Governor
Jonathan B. Howes Secretary
Steven J. Levitas, Deputy Secretary
a
Imo` It?
4j
[D F= F1
Division of Water Quality
Environmental Sciences Branch
4401 Reedy Creek Road
Raleigh, N.C. 27607
FAX:[phone]
FAX TO: ? (, m1 ? i vo ' 'J, I FAX NUMBER:
FROM:
PHONE:
I NO. OF PAGES INCLUDING THIS SHEET: (1-2 1
Environmental Review Tracking Sheet W13
DWQ - Water Quality Section
?
M.
Env. Sciences Branch (WQ Lab)
* Wetlands
O John Dorney
O Cyndi Bell (wr)
oric Galamb (others)
Bio. Resources, Habitat, End. Species
O Trish MacPherson
O Kathy Herring (foresdoxwMQw)
O
Toxicology
O Larry Ausley
O
Planning Branch (Archdale - 6th)
O
FROMO Michelle Suverkrubbe, Planning Branch
<?
Technical Support Branch (Archdale 9th)Pc??F?T9 l99J
O Coleen Sullins, P&E
O Dave Goodrich, P&E, NPDES
O Kim Colson, P&E, State
O Bradley Bennett, P&E, Stormwater
O Ruth Swanek, Instream Assess. (modeling)
O Carla Sanderson, Rapid Assess.
O
Operations Branch (Archdale 7th)
O Kent Wiggins, Facility Assessment
O Tom Poe, Pretreatment
O Lisa Martin, Water Supply Watershed
Regional Water Quality Supervisors
O Asheville O Mooresville O Washington
O Fayetteville • O Raleigh O Wilmington
O Winston-Salem
BE qF -003 - LaW16g d% . 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.
Thank you for your assistance. Suggestions for streamlining and expediting this process are greatly
appreciated!
Notes:
I can be reached at:
phone: [phone], ext. 567 fax: [phone] e-mail: [e-mail]
misAcircmemo - mac version
.d
DEPARTMENT4OF THE ARMY
Wilmington District, Corps of Engineers
Post Office Box 1890
Wilmington, North Carolina 28402-1890
CESAW-EP-PE-97-0011
PUBLIC NOTICE
AND
NOTICE OF AVAILABILITY
ENVIRONMENTAL ASSESSMENT
July 11, 1997
USE OF HOPPER DREDGE WITH OVERFLOW
AS AN ADDITIONAL MAINTENANCE DREDGING METHOD FOR
PORTIONS OF WILMINGTON HARBOR, NORTH CAROLINA
JULY 1997
TO WHOM IT MAY CONCERN:
Wilmington Harbor is an approximately 38-mile Federal navigation project located along
the Cape Fear and Northeast Cape Fear Rivers in southeastern North Carolina (Figure 1). In
the Cape Fear River below the mouth of the Brunswick River, the Wilmington Harbor Federal
Channel is 400 feet wide by 38 feet deep. Maintenance dredging in Wilmington Harbor using
a hopper dredge is currently allowed from Lower Big Island Channel downstream (Figure 1),
but in the river overflow of water from the hopper in order to obtain an economic load is only
allowed in areas that are generally greater than 95 percent sand (but at least 90 percent).
Excluded from overflow are 7.9 miles of the following channels (less than 90 percent sand):
Keg Island, Lower Lilliput and Lower and Upper Midnight. The proposed action would involve
hopper dredging with overflow in all these reaches. In addition, the use of hopper dredging
with overflow is proposed to extend 2.9 miles upstream from Lower Big Island Channel to the
mouth of the Brunswick River. This extension contains Upper Big Island and Lower and Upper
Brunswick Channels, which are mostly greater than 90 percent sand. Including this 2.9-mile
extension and 7.9-mile length indicated above, a total of 10.8 miles of channel would be added
to hopper dredging with overflow maintenance method. All disposal would be in the
Wilmington Ocean Dredged Material Disposal Site (ODMDS) located beyond 3 miles offshore
of the mouth of the Cape Fear River [in accordance with Section 103 of the Marine Protection
Research and Sanctuaries Act of 1972, as amended (MPRSA 1972)].
F
The 10.8 miles of channels where hopper dredging and/or overflow is proposed for the
first time are currently maintained and are anticipated to be maintained on a 2-4 year
frequency. The average annual volume to be removed from these channels is about 320,000
cubic yards.
The Wilmington Harbor environment is discussed in detail in the following three final
environmental impact statements (FEIS). The environmental assessment (EA) described in this
notice only adds information concerning the monitoring data collected March 27, 1997, during
the test overflow of the hopper dredge MCFARLAND:
1. U.S. Army Corps of Engineers, Wilmington District. October 1989. Final
Environmental Impact Statement, Long-Term Maintenance of Wilmington Harbor, North
Carolina.
2. U.S. Army Corps of Engineers, Wilmington District. June 1996. Final Feasibility
Report and Environmental Impact Statement, on Improvement of Navigation, Cape Fear-
Northeast Cape Fear Rivers Comprehensive Study, Wilmington, North Carolina.
3. U.S. Environmental Protection Agency, Region IV. October 1983. Final
Environmental Impact Statement, Savannah, Georgia; Charleston, South Carolina; and
Wilmington, North Carolina, Ocean Dredged Material Disposal Site Designation.
A Section 401 (P.L. 95-217) Water Quality Certificate is required for overflow of the
hopper dredge. A Section 401 Water Quality Certification has been requested from the North
Carolina Division of Water Quality. A Section 404(b)(1) (P.L. 95-217) Evaluation report for the
overflow of the hopper dredge has been prepared and included in the EA.
The work will not affect any species currently on the Federal list of threatened or
endangered species.
The proposed work has been evaluated pursuant to the provisions of the National
Historic Preservation Act of 1966, as amended. No known archaeological or historical
resources will be affected by the proposed action.
A list of Federal, State, and local agencies with whom this activity is being coordinated is
included with the FEIS No. 2, above.
The decision whether to perform this work will be based on an evaluation of the probable
impact, including cumulative impacts of the proposed activity on the public interest. That
decision will reflect the national concern for both protection and utilization of important
resources. The benefits which may reasonably be expected to accrue from the proposal must
be balanced against its reasonably foreseeable detriments. All factors which may be relevant
to the proposal will be considered, including the cumulative effects thereof; among those are
conservation, economics, aesthetics, general values, flood hazards, flood plain values, land
use, navigation, shoreline erosion and accretion, recreation, water supply and conservation,
water quality, energy needs, safety, food and fiber production, mineral needs, considerations
of property ownership, and in general, the needs and welfare of the people.
2
This notice is being distributed to all knovrn interested persons concurrent with circulation
of the EA. For accuracy and completeness of record, all data in support of or in opposition to
the work should be submitted in writing within 30 days of the date of this notice setting forth
sufficient detail to support convictions. Any person who has an interest which may be affected
by the proposed action may request a public hearing. The request must be submitted in
writing to the District Engineer within 30 days of the date of this notice and must clearly set
forth the interest which may be affected and the manner in which the interest may be affected
by this activity. All correspondence should refer to the title, number, and date of this notice.
For further information or to receive a copy of the EA, contact Mr. Frank Yelverton, U.S. Army
Corps of Engineers, Post Office Box 1890, Wilmington, North Carolina 28402-1890, telephone
[phone].
C. E. Shuford, Jr., P.
Acting Chief, Engineering
and Planning Division
Attachment
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i
ENVIRONMENTAL ASSESSMENT
USE OF HOPPER DREDGE WITH OVERFLOW
AS AN ADDITIONAL MAINTENANCE DREDGING METHOD FOR
PORTIONS OF WILMINGTON HARBOR, NORTH CAROLINA

TABLE OF CONTENTS
Heading Page No.
1.00 PROJECT DESCRIPTION ...........................................................................1
2.00 PURPOSE AND NEED ................................................................................2
3.00 ALTERNATIVE DREDGING AND DISPOSAL METHODS ..........................2
3.01 FEIS Maintenance Methods ..............................................................2
3.02 Additional Hopper Dredge Maintenance Alternative .........................3
3.03 Additional Disposal Areas .................................................................4
4.00 ENVIRONMENTAL EFFECTS .....................................................................4
4.01 Water Quality ....................................................................................5
4.02 Aquatic Resources ............................................................................7
4.03 Endangered Species .........................................................................7
4.04 Ocean Disposal of Dredged Material ................................................8
5.00 COORDINATION .........................................................................................8
6.00 CONSISTENCY DETERMINATION FOR NC COASTAL MANAGEMENT
PROGRAM ...............................................................................................9
7.00 LIST OF RECIPIENTS .................................................................................9
8.00 POINT OF CONTACT ..................................................................................9
9.00 ENVIRONMENTAL COMMITMENTS ...........................................................9
10.00 REFERENCES ...........................................................................................9
11.00 FINDING ..................................................................................................10
r
TABLE OF CONTENTS (Cont'd)
Table
LIST OF TABLES
Page No.

1 Hopper Dredge MCFARLAND Efficiency With and Without +
Overflow ..........................................................................................11
2 Characteristics of Surface Sediments in the Wilmington Harbor,
North Carolina, Channels ................................................................12
3 Hopper Dredge Overflow of Lower Midnight Channel Sediments,
Wilmington Harbor, North Carolina .................................................13
4 Hopper Dredge Overflow of MOTSU Sediments, Wilmington
Harbor, North Carolina ....................................................................14
Figure
LIST OF FIGURES
Page No.
1 Hopper Dredging Wilmington Harbor, North Carolina .........................15
2 Hopper Dredge Overflow of Lower Midnight Channel Sediments,
Wilmington Harbor, North Carolina .................................................16
3 Hopper Dredge Overflow of MOTSU Sediments, Wilmington
Harbor, North Carolina ....................................................................17
ATTACHMENTS
ATTACHMENT 1 : Evaluation of Section 404(b)(1) Guidelines.

ENVIRONMENTAL ASSESSMENT
USE OF HOPPER DREDGE WITH OVERFLOW
AS AN ADDITIONAL MAINTENANCE DREDGING METHOD FOR
PORTIONS OF WILMINGTON HARBOR, NORTH CAROLINA
July 1997
1.00 PROJECT DESCRIPTION
Wilmington Harbor is an approximately 38-mile Federal navigation project
located along the Cape Fear and Northeast Cape Fear Rivers in southeastern
North Carolina (Figure 1). In the Cape Fear River below the mouth of the
Brunswick River, the Wilmington Harbor Federal Channel is 400 feet wide by 38
feet deep. Maintenance dredging in Wilmington Harbor using a hopper dredge
is currently allowed from Lower Big Island Channel downstream (Figure 1), but
in the river overflow is only allowed in areas that are generally greater than 95
percent sand (but at least 90 percent). Excluded from overflow are 7.9 miles of
the following channels (less than 90 percent sand): Keg Island, Lower Lilliput
and Lower and Upper Midnight. The proposed action would involve hopper
dredging with overflow in all these reaches. In addition, the use of hopper
dredging with overflow is proposed to extend 2.9 miles upstream from Lower Big
Island Channel to the mouth of the Brunswick River. This extension contains
Upper Big Island and Lower and Upper Brunswick Channels, which are mostly
greater than 90 percent sand. Including this 2.9-mile extension and 7.9-mile
length indicated above, a total of 10.8 miles of channel would be added to
hopper dredging with overflow maintenance method. All disposal would be in
the Wilmington Ocean Dredged Material Disposal Site (ODMDS) located beyond
3 miles offshore of the mouth of the Cape Fear River [in accordance with Section
103 of the Marine Protection Research and Sanctuaries Act of 1972, as
amended (MPRSA 1972)].
Currently, maintenance in the Wilmington Harbor Project from Lower Big
Island Channel downstream is usually performed by a bucket and barge dredge
with disposal in the ODMDS and from Upper Big Island upstream maintenance is
performed by a hydraulic pipeline dredge with disposal in the Eagle Island diked
upland disposal facility (Figure 1). However in the winter of 1997, the Corps of
Engineers hopper dredge MCFARLAND did some maintenance work in the
harbor with disposal in the ODMDS. The MCFARLAND performed some
overflow activity in March 27, 1997, as described in section 4.
The 10.8 miles of channels where hopper dredging and/or overflow is
proposed for the first time are currently maintained and are anticipated to be
maintained on a 2-4 year frequency. The average annual volume to be removed
from these channels is about 320,000 cubic yards.
2.00 PURPOSE AND NEED
The purpose of this environmental assessment (EA) is to discuss the need for
and impacts of using a hopper dredge with overflow as an additional
maintenance method for Wilmington Harbor downstream of the mouth of the
Brunswick River. This EA is also intended to amend the Final Environmental
Impact Statement (FEIS) for the Long-Term Maintenance of Wilmington Harbor
North Carolina (USACE 1989) and, the Final Feasibility Report and
Environmental Impact Statement, on Improvement of Navigation Cape Fear-
Northeast Cape Fear Rivers Comprehensive Study, Wilmington North Carolina
(USACE 1996) to include this maintenance method.
The reasons hopper dredging with overflow in the proposed area are
needed in addition to the other methods indicated in the FEISs are:
a. Bucket and barge dredging methods are not efficient, hydraulic
pipeline dredging methods lack sufficient disposal capacity in the middle harbor,
and disposal areas may not be available during emergencies.
b. Hopper dredging with overflow is more efficient than hopper dredging
without overflow.
c. Hopper dredging with overflow should not adversely impact the
environment.
3.00 ALTERNATIVE DREDGING AND DISPOSAL METHODS
According to USACE 1989 and 1996, several maintenance dredging and
disposal methods are allowed from the mouth of the Brunswick River
downstream. These methods are described below plus the proposed additional
hopper dredge maintenance alternative.
3.01 FEIS Maintenance Methods.
Hydraulic pipeline dredging with disposal in Eagle Island or in the
disposal islands adjacent to the ship channel. Disposal in Eagle Island
2
(Figure 1) using a hydraulic pipeline dredge is still planned from the Upper Big
Island Channel northward. However, there may be occasions when dike repair
or other activities are needed to Eagle Island, and maintenance is urgently
needed in the nearby ship channels, In such situations, Eagle Island would not
be available for a hydraulic pipeline dredge.
Downstream of the mouth of the Brunswick River, the use of a hydraulic
pipeline dredge with disposal in diked disposal islands adjacent to the channel is
no longer a viable option. All these islands are essentially full and would only be
occasionally available for small volumes of dredged materials. Raising the dikes
substantially is not feasible because the dikes are currently eroding, the islands
are too small, or the dike foundations are unsatisfactory. Expansion of these
islands into the estuary is not a viable option due to the associated adverse
environmental impacts (USACE 1989).
Bucket and barge dredging with disposal in the ODMDS from Lower
Big Island Channel downstream through Lower Swash Channel. This
method has not proven efficient in maintenance dredging. Thin shoals over a
substantial area are a particular problem for bucket and barge dredging
methods. The bucket excavates the bottom unevenly, leaving ridges between
bucket grabs. These ridges are difficult to level and according to surveys, the
uneven bottom may lead to increased shoaling rates.
Hopper dredging with disposal in the ODMDS from Lower Big Island
Channel downstream through Baldhead Shoal Channel. Overflow of water
from the hopper to allow efficient loading was addressed for the Baldhead Shoal
Channel and areas where the sediments are at least greater than 90 percent
sand. From the Lower Big Island Channel to Lower Midnight Channel, overflow
is only allowed in the Upper Lilliput Channel since it contains greater than 90
percent sand.
3.02 Additional Hopper Dredge Maintenance Alternative.
Hopper dredging with overflow in all channels downstream of the
mouth of the Brunswick River would be a valuable additional maintenance
dredging method. For example, the hopper dredge MCFARLAND can hold
about twice as much sediment if the dredge was allowed to overflow water to
obtain an economic load (Table 1).
As indicated above, in the upper harbor (around river mile 20 upstream to
the mouth of the Brunswick River, Figure 1), maintenance dredging is usually
performed with a hydraulic pipeline dredge with disposal in the Eagle Island
3
diked upland facility. Therefore, the use of a hopper dredge in this area will be
rare. Probably the only time hopper dredging would be used in the upper harbor
is if emergency dike repair work in Eagle Island would temporarily preclude its
use as a disposal area (has not occurred to date), or a shoal needed to be
removed and a hydraulic pipeline or bucket and barge dredge was not available.
In 1995, emergency approval was obtained to us a bucket and barge dredge to
remove a 60,000 cubic yards shoal in the Lower Brunswick Channel. A bucket
and barge dredge was used because one was already in the harbor performing
maintenance dredging.
From the upper harbor without overflow from a hopper dredge, the
average volume dredged per cycle hour is about 225 cubic yards (Table 1).
However if overflow is permitted, the average volume dredged per cycle hour is
about 350 cubic yards. Thus with overflow the dredge would be in upper section
of the harbor about 36 percent fewer days, and reduced dredging time would
mean lower costs and reduced environmental effects.
For the middle section of the harbor (around river mile 10-15, Figure 1)
where the disposal islands are full, without overflow, the average volume
dredged per cycle hour is about 275 cubic yards (Table 1). However if overflow
is permitted, the average volume dredged per cycle hour is about 409 cubic
yards. Thus with overflow the dredge would be in middle section of the harbor
about 33 percent fewer days, and as indicated above reduced dredging time
would mean lower costs and reduced environmental effects.
3.03 Additional Disposal Areas.
Additional disposal areas for use by a hydraulic pipeline dredge are being
investigated through the preparation of a Dredged Material Management Plan
(DMMP) for the harbor. If this plan identifies additional disposal area(s) for
hydraulic pipeline dredges in the harbor, such areas would not be ready for use
until about 2001. Therefore, hopper dredging with overflow from the mouth of
the Brunswick River downstream is needed for an alternative maintenance
method for the next several years.
4.00 ENVIRONMENTAL EFFECTS
The Wilmington Harbor environment is discussed in detail in the following three
FEISs. This EA will only add information concerning the monitoring data
collected March 27, 1997, during the test overflow of the hopper dredge
MCFARLAND:
4
a. Final Environmental Impact Statement, Long-Term Maintenance of
Wilmington Harbor, North Carolina (USACE 1989).
b. Final Feasibility Report and Environmental Impact Statement, on
Improvement of Navigation, Cape Fear-Northeast Cape Fear Rivers
Comprehensive Study, Wilmington, North Carolina (USACE 1996).
c. Final Environmental Impact Statement, Savannah, Georgia;
Charleston, South Carolina, and Wilmington, North Carolina, Ocean Dredged
Material Disposal Site Designation. (USEPA 1983).
4.01 Water Quality.
Two overflow events from the MCFARLAND were monitored in the middle
section of the harbor where the hopper dredge was working on March 27, 1997.
The first discussed here is the results of overflow monitoring on the dredged
material from Lower Midnight Channel (LMC). The sediments in LMC are about
76 percent sand and are generally representative of the channels below the
mouth of the Brunswick River where overflow is currently not allowed (Table 2).
Table 3 indicates a major reduction in suspended sediment concentration and
turbidity with distance from the dredge. Both parameters neared background
values at 3,300 feet from the dredge. Other measured water quality parameters
(temperature, salinity, and dissolved oxygen), remained relatively constant. The
suspended sediment data for LMC are graphed on Figure 2 along with the
estimated values from a study conducted in the Chesapeake Bay (Nichols et. al
1990). The percent sand in the Chesapeake Bay sediments were less than 20
percent and only data for mid-depth were available. The background and
hopper dredge overflow weir suspended sediments are also plotted on Figure 2.
This figure indicates that the concentrations of suspended sediments are lower
for LMC for all locations compared to Chesapeake Bay and the LMC levels
approach the background concentrations at a shorter distance. The major
difference between the LMC and Chesapeake concentrations is probably due to
the higher percentage of sand in the LMC sediments.
The North Carolina Division of Water Quality (NCDWQ) standard for
turbidity for saltwater is 25 NTUs. There is no NCDWQ suspended sediment
standard for the Cape Fear River. The surface and mid-depth background
turbidity values measured March 27, 1997, were both below 25 NTUs (16.0 and
14.3, respectively) whereas the bottom value was slightly above the standard
(28.5) probably due to turbulence caused by river currents (about 2.0 knots)
moving across the sediments. At 1,600 feet from the dredge during the overflow
test, the surface value returned to below 25 NTUs and at 3,300 the mid-depth
value returned to below standard (Table 3). The bottom value was only slightly
higher than the background value (30.2 vs. a background of 28.5 NTUs) at 3,300
5
feet. This turbidity plume is confined between the dredge and 3,300 feet since
the dredge is steering into the river currents averaging about 2.0 knots. The
lateral extend of the plume was not measured in this test, but the plume should
be confined principally to the 400-foot-wide channel limits since the current
follows the channel alignments. In the Chesapeake Bay study even though the
sediments there were less than 20 percent sand, of the dredged material in the
overflow, "less than 1 percent drifts beyond the channel environs" (Nichols et. al
1990).
The second overflow monitoring was on the dredged material from Military
Ocean Terminal, Sunny Point (MOTSU, Table 4). `INIOTSU is not a part of the
Wilmington Harbor ship channel but overflow of the hopper from sediments
dredged from MOTSU should represent a worst-case scenario for suspended
sediments and turbidity since the MOTSU sediments in the area dredged are
about 35 percent sand (65 percent silt and clay). The lowest percentage sand in
the Wilmington Harbor channels to be dredged is 53.5 percent (46.5 percent silt
and clay, Table 2). Table 4 indicates a major reduction in suspended sediment
concentration and turbidity with distance from the dredge with both parameters
approaching background values at 1,600 feet from the dredge. Time did not
permit measurements at 3,300 feet from the dredge, but it is anticipated that
near background levels would also be reached at that distance. The rest of the
parameters remained relatively constant. The suspended sediment data for
MOTSU is graphed on Figure 3 along with the estimated values from the
Chesapeake Bay Study (Nichols et. al 1990). As indicated above, the percent
sand in the Chesapeake Bay sediments were less than 20 percent and only data
for mid-depth were available. The background and hopper dredge overflow weir
suspended sediments are also plotted (Figure 3). This figure indicates that the
concentrations of suspended sediments are lower for MOTSU for all locations
compared to Chesapeake Bay and the MOTSU levels approach the background
concentrations at a shorter distance. As indicated for the LMC sediments, the
major difference between the MOTSU and Chesapeake concentrations is
probably due to the higher percentage of sand in the MOTSU sediments.
As with the LMC test, at 1,600 feet from the dredge during the overflow
test, the surface value for turbidity returned to below the NCDWQ standard of 25
NTU's. Measurements were not taken at 3,300 feet due to time restraints, but it
is anticipated that the mid-depth and bottom values would be below or near the
standard as was the case for the LMC test.
The North Carolina Division of Environmental Management will
concurrently review this EA and the Corps' request for a Section 401 (P.L. 95-
217) Water Quality Certificate to authorize the work that may impact water
quality under the proposed action. Also, the Section 404(b)(1) evaluation for the
discharge of dredged material is included in Attachment A.
6
4.02 Aquatic Resources.
The only change to resources from the Wilmington Harbor FEISs is the
increased turbidity and suspended solids levels associated with overflow of the
hopper dredge. Without overflow, turbidity/suspended solids (TSS) is confined
to the near bottom zone from agitation associated with the hopper draghead.
• This agitation occurs for the 13 minutes of dredging during a each dredging
cycle, or an average of about 0.6-0.7 hours per day (Table 1). With overflow,
increased TSS levels would occur about 1.12 hours during each dredging cycle
or an average of about 3-4 hours per day.
The proposed action should also have minimal impact on other aquatic
resources. With or without overflow, the hopper dredge would be dredging
sediment the same number of total hours during the North Carolina Division of
Marine Fisheries dredging window (August 1 to January 31). However since
overflow is more efficient (more volume per cycle hour, Table 1), the dredge
would be in the harbor 33-36 percent fewer days. Hopper dredging with
overflow will be confined to the Wilmington Harbor ship channel from the mouth
of the Brunswick River downstream. In this area, primary nursery areas (PNA)
for marine fisheries are not within 300 yards either side of the center line of the
channel, and as indicated above, the TSS plume is expected to remain within
the channel.
4.03 Endangered Species.
Endangered species issues were addressed through the EIS process
associated with the 1989 and 1996 FEISs (USACE 1989 and 1996) for
Wilmington Harbor. In the area where hopper dredging is currently allowed
(Lower Big Island downstream), the only change from the FEISs would be that
overflow would be performed in about 7.9 more miles of channel. The TSS
associated with the overflow should not impact any of the endangered species
(sea turtles, shortnose sturgeon and manatee) in the Harbor. The sea turtles
and manatee breathe air and the shortnose sturgeon is highly mobile and can
avoid the dredge. Overflow should reduce potential impacts since the dredge
would be in the harbor about 1/3 fewer days. Also, overflow will essentially
double each load (1,230 vs. 2,400 cubic yards, Table 1) in the hopper, resulting
in the number of round trips to the ODMDS being reduced by about half. This
will reduce the potential for interaction with list species.
As indicated above, using a hopper dredge to maintain the upper harbor
would be a rare since this portion of the harbor is routinely maintained with a
hydraulic pipeline dredge with disposal in Eagle Island.
7
The use of a hopper dredge will be in accordance with the National
Marine Fisheries Service regional biological opinion dated April 9, 1997, and
August 25, 1995 (NMFS 1997, 1995).
Based on the above, the proposed action is not anticipated to adversely
effect endangered species.
4.04 Ocean Disposal of Dredged Material.
Only dredged materials which have been evaluated in accordance with
EPA's Ocean Dumping Regulations and Criteria (40 CFR 220-229) and found
acceptable may be transported for disposal in the Wilmington ODMDS under
section 103 of MPRSA 1972. Wilmington Harbor channel sediments from Lower
Big Island Channel downstream to Baldhead Shoal channel may currently be
transported for ocean disposal. A Section 103 evaluation of Wilmington Harbor
Channel sediments from the Anchorage Basin through Baldhead Shoal Channel
has been accomplished. This evaluation includes all channels where hopper
dredging with overflow is proposed. The evaluation is being submitted to EPA
Region IV for concurrence.
5.00 COORDINATION
Representatives from the agencies listed below were contacted regarding the
proposed action and preparation of the EA. Representatives from these
agencies were involved in one or both of the March 1997 field trips regarding
overflow from the MCFARLAND hopper dredge in Wilmington Harbor. The
purpose of the March 7, 1997, trip was to familiarize the agencies with the
operations of a hopper dredge. The purpose of the
March 27, 1997, trip was to monitor the overflow of the hopper dredge.
NC Division of Coastal Management
NC Division of Environmental Quality
NC Division of Marine Fisheries
NC Wildlife Resources Commission
U.S. Fish and Wildlife Service
National Marine Fisheries Service
Agencies contacted but not able to attend the field trips:
U.S. Environmental Protection Agency
8
6.00 CONSISTENCY DETERMINATION FOR NC COASTAL MANAGEMENT
PROGRAM
Based on the information presented above, the proposed action is consistent
with the Coastal Management Program of the State of North Carolina.
7.00 LIST OF RECIPIENTS
The list of recipients is the same as indicated on pages EIS-74 to EIS-76 of
USACE 1996.
8.00 POINT OF CONTACT
Any comments or questions regarding this EA should be addressed to Mr. Frank
Yelverton, Environmental Resources Section, U.S. Army Corps of Engineers,
Wilmington District, PO Box 1890, Wilmington, North Carolina 28402-1890.
Telephone contact is 910-251-4640.
9.00 ENVIRONMENTAL COMMITMENTS
Hopper dredging in the new areas proposed for overflow will be conducted
during the NCDMF dredging window (August 1 - January 31) and in accordance
with the National Marine Fisheries Service Biological Opinions for hopper
dredging (NMFS 1995 and 1997).
10.00 REFERENCES
National Marine Fisheries Service. 1997. Interim Biological Opinion, U.S. Army
Corps of Engineers, South Atlantic Division. The continued hopper dredging of
two channels and one borrow area in the southeastern United States during
1997.
National Marine Fisheries Service. 1995. Biological Opinion, U.S. Army Corps
of Engineers, South Atlantic Division. The hopper dredging of channels and
beach nourishment activities in the Southeastern United States from North
Carolina through Florida East Coast.
Nichols, M., R.J. Diaz and L.C. Schaffner. 1990. Effects of Hopper Dredging
and Sediment Dispersion, Chesapeake Bay. Environ. Geol. Water Sci. Vol. 15,
No. 1. 31-43.
9
U.S. Army Corps of Engineers, Wilmington District. 1989. Final Environmental
Impact Statement, Long-Term Maintenance of Wilmington Harbor, North
Carolina, Wilmington, NC, October 1989.
U.S. Army Corps of Engineers, Wilmington District. 1996. Final Feasibility
Report and Environmental Impact Statement, on Improvement of Navigation,
Cape Fear-Northeast Cape Fear Rivers Comprehensive Study, Wilmington,
North Carolina, Wilmington, NC, June 1996.
U.S. Environmental Protection Agency. 1983. Final Environmental Impact
Statement, Savannah, Georgia; Charleston, South Carolina; and Wilmington,
North Carolina, Ocean Dredged Material Disposal Site Designation. October
1983.
11.00 FINDING
The proposed action should not significantly affect the quality of the human
environment; therefore, an Environmental Impact Statement will probably not be
required. If this opinion is upheld following circulation of this EA, a Finding of No
Significant Impact (FONSI) will be signed and circulated.
10
4
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TABLE 2. CHARACTERISTICS OF SURFACE SEDIMENTS IN THE WILMINGTON HARBOR, NC
CHANNELS.
Channel
Baldhead Shoal
Offshore reaches
Inside Reaches
Smith Island
Baldhead-Caswell
Southport
Battery Island
Lower Swash
Horseshoe Shoal
Reaves Point
Lower Midnight
Upper Midnight
Lower Lilliput
Upper Lilliput
Keg Island
Upper and Lower Big Island
Lower Brunswick
Upper Brunswick
Fourth East Jetty and Between
Anchorage Basin
Between Memorial and
Hilton Railroad Bridges
Above Hilton Railroad Bridge
%Gravel %Sand % Silt & Clay
0.0 73.2 26.8
0.0 98.7 1.3
7.9 92.0 0.1
18.0 80.5 1.5
12.5 85.5 2.0
38.0 61.0 1.0
27.0 70.0 3.0
0.0 98.0 2.0
0.0 99.0 1.0
0.0 76.0 24.0
0.0 82.5 17.5
0.0 53.5 46.5
0.0 98.0 2.0
0.0 63.0 37.0
2.0 94.0 3.0
0.0 92.7 7.3
0.0 57.0 43.0
0.0 80.0 20.0
0.0 6.0 94.0
10.0 55.0 35.0
0.0 58.0 42.0
12
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ATTACHMENT 1
SECTION 404(B)(1) (PUBLIC LAW 95217) EVALUATION
USE OF HOPPER DREDGE WITH OVERFLOW
AS AN ADDITIONAL MAINTENANCE DREDGING METHOD
FOR PORTIONS OF WILMINGTO14 HARBOR
WILMINGTON, NORTH CAROLINA
a
1
1
T
t
7
7
7
0 'S
..A ,f!Ea R
SECTION 404(B)(1) (PUBLIC LAW 95-217) EVALUATION
USE OF HOPPER DREDGE WITH OVERFLOW
AS AN ADDITIONAL MAINTENANCE DREDGING METHOD
FOR PORTIONS OF WILMINGTON HARBOR
WILMINGTON, NORTH CAROLINA
Evaluation of Section 404(b)(1) Guidelines
40 CFR 230
1. Review of Compliance (230.10(a)-(d))
Review of the NEPA Document indicates:
a. The discharge represents the least
environmentally damaging practicable
alternative and if in a special aquatic
site, the activity associated with the
discharge must have direct access or
proximity to, or be located in the
aquatic ecosystem to fulfill its basic
purpose (if no, see section 2 and NEPA
document);
b. The activity does not: 1) violate
applicable State water quality
standards or effluent standards
prohibited under Section 307 of the
CWA; 2) jeopardize the existence of
federally listed endangered or
threatened species or their habitat;
and 3) violate requirements of any
federally designated marine sanctuary
(if no, see section 2b and check
responses from resource and water
quality certifying agencies);
C. The activity will not cause or
contribute to significant degradation
of waters of the U.S. including adverse
effects on human health, life stages of
organisms dependent on the aquatic
ecosystem, ecosystem diversity,
productivity and stability, and
recreational, aesthetic, and
economic values (if no, see section
2);
d. Appropriate and practicable steps have
been taken to minimize potential
adverse impacts of the discharge on
the aquatic ecosystem
(if no, see section S).
Proceed to Section 2
1, 2/ See page A-6
Preliminary 1/ Final 2/
YESI 1 N01-1* YESIXI N011
YESI 1 N01-1* YESIXI N011
YESI 1 N01-1* YESIXI N011
YESI 1 N01-1* YESIXI N011
A-1
4• Dis osal Site Determinations (230.11(f)).
a. The following factors as appropriate,
have been considered in evaluating the
disposal site.
(1) Depth of water at disposal site .
. IX-1
(2) Current velocity, direction, and
variability at disposal site ,
. IXI
(3) Degree of turbulence
. IXI
(4) Water column stratification
. IXI
(5) Discharge vessel speed and
direction . . .
.. IXI
(6) Rate of discharge . . . . .
. IXI
(7) Dredged material characteristics
(constituents, amount and type
of material, settling velocities). . . ,
. IXI
(8) Number of discharges per unit of
time . . . . .
. IXI
(9) Other factors affecting rates and
patterns of mixing (specify)
List appropriate references.
Reference: Final Environmental Impact Statement, Cape Fear -
Northeast Cape Fear Rivers Comprehensive Study, New Hanover and
Brunswick Counties, North Carolina, June 1996.
Environmental Assessment, Use of Hopper Dredge with Overflow
as an Additional Maintenance Dredging Method for Portions of
Wilmington Harbor, North Carolina, July 1997.
b. An evaluation of the appropriate factors in
4a above indicates that the disposal site
and/or size of mixing zone are acceptable . . . .YES IXI NO I_
_ I*
5• Actions to Minimize Adverse Effects (Subpart H).
All appropriate and practicable steps have been taken,
through application of recommendations of 230.70-230.77,
to ensure minimal adverse effects of the proposed
discharge. List actions taken. -
YES IXI NO I I*
See sections 4.01 through 4.04 and 8.00 of the environmental assessment.
Return to section 1 for final stage of com liance review. See also
note 3/, pa 2e A-6
*See page A-6
A-4

6. Factual Determinations (230.11).
A review of appropriate information as identified in
items 2-5 above indicates that there is minimal
potential for short- or long-term environmental
effects of the proposed discharge as related to:
a. Physical substrate at the disposal site
(review sections 2a, 3, 4, and 5).
b. Water circulation, fluctuation, and salinity
(review sections 2a, 3, 4, and 5).
C. Suspended particulates/turbidity
(review sections 2a, 3, 4, and 5).
d. Contaminant availability
(review sections 2a, 3, and 4).
e. Aquatic ecosystem structure and function
(review sections 2b and c, 3, and 5).
f. Disposal site
(review sections 2, 4, and 5).
g. Cumulative impact on the aquatic
ecosystem.
h. Secondary impacts on the aquatic
ecosystem.
7. Findings.
a. The proposed disposal site for discharge of
dredged or fill material complies with the
Section 404(b)(1) guidelines. . . . . . . . . .
b. The proposed disposal site for discharge of
dredged or fill material complies with the
Section 404(b)(1) guidelines with the
inclusion of the following conditions:
*See page A-6
A-5
YES 1XI NO 1 -1*
YES IXI NO 1 1*
YES IXI NO 1 1*
YES IXI NO 1 1*
YES IXI NO 1 -1*
YES IXI NO I I*
YES 1XI NO 1 -1*
YES IXI NO 1 1*
IXI
I I

C. The proposed disposal site for discharge of
dredged or fill material does not comply with
the Section 404(b)(1) guidelines for the
following reasons(s):
(1) There is a less damaging practicable alternative. . . . . I I
(2) The proposed discharge will result in significant
degradation of the aquatic ecosystem . . . . . . . . . . I I
(3) The proposed discharge does not include all
practicable and appropriate measures to minimize _ t
potential harm to the aquatic ecosystem . . . . . . . . . I I
B
C.E.Shuford, Jr., P.E.
Acting Chief, Engineering
and Planning Division
Date: e-77
*A negative, significant, or unknown response indicates that the permit application may
not be in compliance with the Section 404(b)(1) Guidelines.
1/ Negative responses to three or more of the compliance criteria at this stage
indicate that the proposed projects may not be evaluated using this "short form
procedure." Care should be used in assessing pertinent portions of the technical
information of items 2 a-d, before completing the final review of compliance.
2/ Negative response to one of the compliance criteria at this stage indicates that the
proposed project does not comply with the guidelines. If the economics of navigation
and anchorage of Section 404(b) (2) are to be evaluated in the decision-making process,
the "short form evaluation process is inappropriate."
3/ If the dredged or fill material cannot be excluded from individual testing, the
"short-form" evaluation process is inappropriate.
A-6
M
NCDFHNP, I,IIRO Fax:[phone]oo4 Sep 23 '97 9:47 P.01.
MEMORANDUM
Septemb¢r 23, 1997
TO: John Doriney
FROM: Fritz Rohde
SUBJECT; Hopper Dredge Overfly
&L MOTSU
The North Carolina Divioio'. of Marine Fisheries has concerns
with the proposed overflow at MbTSU. While the test overflow in
the river channel in March 1997 demonstrated little impact
because, of the bottom type (pri Ar. i _.y sand), the bottom material
in MOTH ie.moatly milt which Zn have a greater impact to_the
surrounding 'area. Although not designaLe.d as primary nursery
areas, there are shallow water areas near MOTSU which do have
functional values of nursery areas. Because of the proximity of
these areas, the Diviaian requo tm that dredge overflow in MOTSU
be reatticted to times of non-p ak biological activity (the
normal dredging window for the ape Fear River),
POV-11'. Fax Note
w.:
DEPARTMENT OF THE ARMY
WILMINGTON DISTRICT, CORPS OF ENGINEERS
P.O. BOX 1890
WILMINGTON, NORTH CAROLINA 28402-1890
IN REPLY REFER TO August 13, 1997
Environmental Resources Section
SUBJECT: 401 Water Quality Certification
Hopper Dredge with Overflow -
New Hanover County
DWQ # 970625
Mr. John Dorney
Environmental Sciences Branch
Water Quality Certification Program
4401 Reedy Creek Road
Raleigh, North Carolina 27607
Dear Mr. Dorney:
O
9
Wilmington Harbor dredging g`?c4,
0Fs
We have reviewed your letter (copy enclosed), dated July 31, 1997, on the above
subject and believe that the potential conditions to the 401 Certification listed are not
warranted. We provide the following information in support of our position.
The highest concentration of the turbidity and suspended sediment plume will be
in the channel directly behind the dredge since the dredge is steering into a 2 knot
current. This plume behind the dredge was monitored twice on March 27, 1997, as
indicated in the July 1997 EA (USACE 1997). The results reported in the EA indicate
that both parameters return to background or near background levels within 3,300 feet
of the dredge. This plume will not extend as far laterally from the dredge since the
plume would have to move perpendicular to the current.
Even if the plume did extend as far laterally as it did behind the dredge, what
would be the worst case sediment redeposition layer? At 1,000 feet from the channel,
about where the primary nursery areas (300 yards either side of the channel) start from
Upper Lilliput Channel upstream, the average background suspended sediment
concentration (SSC) from the surface to 23 feet deep mean low water (MLW) is
25.5 mg/I (water from deeper than 23 feet is not anticipated to reach the flats adjacent
to the channel). For the observed worst case (highest SSC of the two tests), the
average SSC from the surface to 23 feet deep MLW at 1,000 feet from the dredge was
183 mg/I, 7.2 times background. This elevated condition may occur up to 7 hours per
day for a maximum of 30 days a year for a particular channel in the harbor. This would

-2-
be equivalent to an overflow SSC for about 9 days a year [(7 hours X 30 days)/24 hours
per day]. If average sedimentation in the primary nursery areas were about 1.0 cm per
year due to background SSC, the overflow SSC would add an additional 0.18 cm per
year [(7.2 X 1.0 cm per year)/365 days per year) X 9 days per year ]. Remember this
would be a worst case! Even if a similar procedure was performed for the SSC only
300 feet from the dredge, the overflow SSC would only add an additional 0.60 cm per
year to be background sedimentation rate. Besides, increased sedimentation
associated with high periodic flood events would probably mask any change due to
overflow from hopper dredging.
Nichols et al., 1990 for hopper dredge overflow in Chesapeake Bay, indicates that
sedimentation about 1,000 feet (275 m) from the channel averaged about 13.2 cm due
to hopper dredging overflow, but benthic communities "in the vicinity of the channel
were not obviously affected by deposition of dredged material." Why did an average of
13.2 cm of sedimentation occur in Chesapeake Bay and at worst 0.18 cm would be
anticipated in Wilmington Harbor? There are two primary reasons. First, 5,000,000
cubic yards were dredged in Chesapeake Bay and only 300,000 cubic yards are
projected to be dredged in Wilmington Harbor. This results in Wilmington Harbor
having 6 percent of the Chesapeake Bay dredged volume over similar channel
distances. Second, the Chesapeake Bay sediments were all less than 20 percent sand
while Wilmington Harbor averages 66 percent sand in the new areas proposed for
hopper overflow. With the much smaller volume and higher percent sand, Wilmington
Harbor would have much less sediment redeposition.
Other studies have also shown that thin layer disposal does not adversely affect
benthic communities. For example, the results reported in Wilber 1992 for Mobile Bay
Estuary, Alabama indicate benthic abundance approximated background levels 2
weeks after dredging had stopped if disposal of sediment was less than 15 centimeters.
Based on the above, we believe that the proposed hopper dredge overflow would
not adversely affect estuarine water quality, benthic resources, or primary nursery
areas in the Cape Fear River. We believe that the monitoring that you request would
be redundant; therefore, we request that the proposed conditions in your July 31, 1997,
letter be removed. If you have any questions, please contact Mr. Frank Yelverton of my
staff at 910-251-4640.
The Military Ocean Terminal, Sunny Point (MOTSU) will also be requesting
permission to overflow a hopper dredge at their facility. This will require modification to
their Department of the Army Section 10 and Section 404 permits and modification to
their 401 certification. We have been asked by MOTSU to be their agent for these
modifications. We will be forwarding to you a request for the modification of the

-3-
401 certification in a few weeks. This request will include information on plume
monitoring for hopper dredge overflow related to MOTSU dredged material. Based on
information we will present related to that request, we also believe additional
monitoring would be redundant at MOTSU.
Sincerely,
bj ?U
hip.
W. Coleng. C
Planning and Environmental Branch
Enclosure
Copy Furnished (with enclosure):
Mr. Steve Benton, Consistency Coordinator
North Carolina Division of Coastal Management
Post Office Box 27687
Raleigh, North Carolina 27611-7687
Mr. Jim Gregson
North Carolina Division of Coastal Management
127 Cardinal Drive
Wilmington, North Carolina 28405
Mr. Jerry Parker
North Carolina Division of Coastal Management
127 Cardinal Drive
Wilmington, North Carolina 28405
Mr. Jim Bushardt
North Carolina Division of Water Quality
127 Cardinal Drive
Wilmington, North Carolina 28405
Mr. Ron Sechler
Habitat Conservation Division
National Marine Fisheries Service
Pivers Island
Beaufort, North Carolina 28516

-4-
Mr. Kevin Moody
US Fish and Wildlife Service
Post Office Box 33726
Raleigh, North Carolina 27636-3726
Dr. Gerald Miller
Office of Environmental Assessment
US Environmental Protection Agency
61 Forsyth Street
Atlanta, Georgia 30303-3104
-5-
References:
Nichols, M., R.J. Diaz and L.C. Schaffner. 1990. Effects of Hopper Dredging and
Sediment Dispersion, Chesapeake Bay. Environ. Geol. Water Sci. Vol. 15, No. 1. 31-
43.
Wilber, P. 1992. Case Studies of the thin-layer disposal of dredged material - Fowl
River, Alabama. U. S. Army Corps of Engineers, Waterways Experiment Station,
Environmental Affects of Dredging, Vol. D-92-5. November 1992.
U. S. Army Corps of Engineers, Wilmington District. 1992. Environmental Assessment,
Use of Hopper Dredge with Overflow as an Additional Maintenance Dredging Method
for Portions of Wilmington Harbor, North Carolina. July 1997.

State of North Carolina
Department of Environment,
Health and Natural Resources 1 • •
Division of Water Quality
James Hunt, governor C) E H N F=1
Jonathan B. Howes, Secretary
A. Preston Howard, Jr., P.E., Director
July 31, 1997
Mr. W. Coleman Long
Wilmington District Corps of Engineers
Environmental Resources Section
P.O. Box 1890
Wilmington, NC 28402-1890
Dear Mr. Long:
RE: 401 Water Quality Certification
Hopper dredge with overflow - Wilmington Harbor dredging
New Hanover County
DWQ # 970625
On 14 July 1997, DWQ staff received your application for use of a hopper dredge with
overflow to facilitate the dredging of Wilmington Harbor. In accordance with 15A NCAC 2H
.0503, an Individual Certification will be needed for this project. I have put the project out to
Public Notice for this purpose. Until the Public Notice process is complete, this project will have
to remain on hold. The public comment period is for 15 days after publication in the local
newspaper.
Also in accordance with the Memorandum of Agreement with our agencies, we have
completed our review of the Certification application and EA and have the following comments
We expect that these conditions will need to be included in the 401 Certification in order to
protect water quality. If these conditions (or modifications thereof based on your review) are
included in the Certification, we anticipate issuing the 401 Certification after the EA/FONSI is
completed.
1. If dredging is done in locations with less than 90% sand, water quality data shall be
collected by the C.S. Army Corps of Engineers for total and suspended residue and turbidity to
determine the later extent of the sediment plume as well as the extent and thickness of the
sediment redeposition on the channel flanks.
2. The effect of sediment redeposition on benthic organisms adjacent to the channel shall
be documented by the U.S. Corps of Engineers by monitoring pre and post benthic abundance and
diversity in areas adjacent to the channel where redeposition is observed.
Division of Water Quality - Environmental Sciences Branch
Environmental Sciences Branch, 4401 Reedy Creek Rd., Raleigh, NC 27607 Telephone [phone] FAX # [phone]
An Equal Opportunity Affirmative Action Employer • 500% recycled/t V. post consumer paper
AUG 07 '97 11:13AM EHNR-PUBLIC WFATPS
NORTH CAROLINA DIVISION OF WATER QUALITY
Water Ouality Section
Wilmington Regional Office
Date: July 25, 1997
To: Melba McGee
From: James H. Gregso
Through: Rick Shiver
Subject: A95 Review
Environmental Assessment
Use of Hopper Dredge With Overflew
US Army Corps of Lngineers
Project Number 98-0037
New Hanover County
P.2/4
The Wilmington District Corps of Engineers proposes to use hopper dredging with
overflow its the Cape Fear River from the mouth of the Brunswick River downstream in areas
where hopper dmlgtnng with overflow is currently not allowed. Hopper dredging with overflow
is currently excluded hi the following reaches: Keg Island, Lower Lilliput, and Lower and Upper
Midnight. Overflow has not been allowed in these areas due to the duality of the sediments
(groatcr than 10 percent fines). All disposal from hopper dredging would be in the EPA
Wilmington Ocean Dredged Material Disposal Site. Hopper dredging with overflow is being
propowd in thane additional areas in order to allow dredges to obtain a more economic load and
to provide a more offtcicnt means of dredging in arras of the river where upland disposal areas
lack sufficient capacity or whcu other disposal options, nuty not be available during emergencies.
On March 7, 1997, staff front the Divi,iu?? of Water Quality participated in a field trip
aboard tho hopper dredge MCFARL.AND along with t?thor State and Federal review agencies.
Tito purpose of the field trip was to observe the operation of ilia MCFARLAND during overflow
and to discuss the concerns of various agmicies over the uverflow operation.
On March 27, 1997, staff from the Division or Water Quality participated In another field
trip in cooperation with the Wiltningtcm District C".ojps of Bngineera to monitor the overflow firma
the hopper dredge MCFARLAND. Water mTnplcs wets collected during two ovetflow events and
analyzed for total and suspended residue, and turbidity. Physical mcasurenients wow taken for
salinity, dissolver) oxygen, and temperature. Witter Aatnples and physical incasurements wort
taken at the surface (0.3 meters), mid-depth (7 meters), and near-bottom (11 meters). For each
overflow event, sunples were collected at the three dc3A.hs of multiple distances behind the dtrlge,
up to 3,300 40 for the overflow of Lower Midull;ht C hasinol wdiments and lip to 1,600 Peet for
. . AUG 07 '97 11:13AM EHNR•PUBLIC AFFAIRS P.3i4
Melba McGee
July 25, 1997
Page Two
the overflow of MOTSU sediments. Results of the physical sampling indicate very little change
in physical pannietexs as a result of sediment overflow. Results of residue and turbidity sampling
for the overflow of Midnight Channel sediments indicate that these parameters approach
background values 3,300 feet behind the dredge. Due to time constraints, samples at 3,300 feet
behind the dredge were not collected for the overflow of MOTSU sediments, however, data that
was collected for this overflow event indicate that residue and turbidity would also likely approach
background values at a distance of 3,300 feet behind the dredge.
A study conducted on the effects of hopper dredging and sediment dispersion in the
Chesapeake Bay by the Virginia Instihtte of Marine Science indicated that 12 % of the total amount
of material removed by the dredge is lost by overflow discharge or draghead resuspension and the
sediment pluthe contained approximately 1.0% of t.hea overflow discharge load. Less than 1. %
drifted beyond the channel "environs". Background concentrations were reached at 5,200 meters
from the discharge point. Sediments dredged in the Chesapeake Bay study were less than 20%
sand while sediments dredged from Lower Midnight Channel were approximately 76% sand.
While monitoring efforts on March 27, 1.997 of Lower Midnight Channel dredging indicate
that surface turbidity values near background approximately 23 minutes after discharge, the
ultimate fate of the sediment plume is stall of concern to this Office. Specifically, what is the
extent of the redeposition of dredged sediments outside the confines of the navigation channel and
what, if any, impact this redeposition will have on bentliic populations. It is reasonable to assume
that redeposition of sediments outside the confines of the navigation channel in the Cape Fear
River should be less than that in the Chesapeake Bay due to the facts that in the Cape Fear River
the current generally flows in the same direction as the channel alignment and the content of fines
in the sediment is much lower in the areas of the Crape Dear River where overtow is proposed
compared to Chesapeake Bay, however, the latera l extent of the sediment plume and the extent
of redeposition sediments were not mea,%tard during the overflow on March 27, 1997.
Hopper dredge overflow will require a Nec;tion 40). Water Quality Certification from this
Division. Thls Office recoinmends that a 401 C;crlifical ion t.?e issued for project as proposed with
the following conditlons:
1. That during the first drWging event when hopper overflow is utilized in areas less
than 90% sand additional data bu colketed to determine the lateral extent of the
sediment plume and the extent and thic=kness of sediment redeposition on the
channel flanks.
AUG 07 '97 11:14AM EHNR•PUBLIC AFF"AIR5
Melba McGee
July 25, 1997
page T'h: W
P. 4/4
2. -That the effect of sediment redeposition on benthic assemblages adjacent. to the
channel be evaluated by monitoring trim dredging henthic, abundance and diversity
adjacent to the channel and monitoring post dredging benthic diversity and
abundance in areas where redeposition is observed.
3. That data collection and sampling methodologies will be coordinated with the
Division of Water Quality (DWO) and other appropriate review agencies. That
monitoring results will be re.viewed by DWO to determine if environmental
impacts associated with hopper dredge overflow should result in rescission of the
401 CertWication by the Director.
cc: Wilmington Regional Office Files
Central Files
John Dorney
Steve Benton
i

aPP??gNT OF Tye,
o`` ym
9
V)
? a
gRCM 3 ?s
United States Department of the
FISH AND WILDLIFE SERVICE
Raleigh Field Office
Post Office Box 33726
Raleigh, North Carolina 27636.3726
September 4, 1997
Colonel Terry R. Youngbluth
District Engineer, Wilmington District
Post Office Box 1890
Wilmington, North Carolina 28402-1890
Attention: Frank Yelverton
Dear Colonel Youngbluth:
Interior
1
The U.S. Fish and Wildlife Service (Service) has reviewed July 11,
1997 Public Notice CESAW-EP-PE-97-0011 and Environmental Assessment
for the Use of Hopper Dredge with overflow. Your staff proposes to
use overflow dredging techniques, in limited circumstances, in the
Wilmington Harbor Navigation channel. The dredge McFarland hosted
a site visit and data collection trip on March 27, 1997.
This is the report of the Service submitted pursuant to, and in
accordance with, provisions of the Fish and Wildlife Coordination
Act (48 Stat. 401, as amended; 16 U.S.C. 661 et seq.) and the
Endangered Species Act of 1973 (87 Stat. 884, as amended; 16 U.S.C.
1531 et seq.).
We do not object to the subject proposal. Based on the available
literature and sampling conducted onsite behind the overflowing
McFarland, we concur that the suspended sediments, when mostly
mineral, move out of suspension or are otherwise dissipated to
below background levels very quickly. Further, we support
continueing efforts to determine environmentally sound parameters
for overflow dredging (e.g., quantifying lateral transport of
sediments).
We appreciate the opportunity to comment on this proposal. Please
call Kevin Moody of my staff at [phone] extension 19 if you
have any questions or comments.
Sincerely,
rohn M. n er
d Supervisor

cc:
DCM, Wilmington, NC (Bob Stroud)
DCM, Raleigh, NC (John Parker)
DMF, Wilmington, NC (Fritz Rohde)
DWQ,Raleigh, NC (John Dorney)
WRC, Kinston, NC (Bennett Wynne)
WRC, Raleigh, NC (Frank McBride)
EPA, Wetlands Regulatory Branch, Atlanta, GA (Thomas Welborn)
NMFS, Beaufort, NC (Larry Hardy)
FWS/R4:KMoody:KM:08/29/97:919/856-4520 extension 19:\wilharb.wpd

September 15, 1997
Mr. W. Coleman Long
Wilmington District Corps of Engineers
Environmental Resources Section
P.O. Box 1890
Wilmington, N.C. 28402-1890
SUBJECT: 401 Water Quality Certification
Hooper Dredge Overflow-Wilmington Harbor
New Hanover County
DWQ# 970625
We have carefully reviewed your August 13, 1997 reply letter
regarding the subject project and the proposed 401 Certification
conditions. Below we have provided a summary of the reasons why we
believe that this additional monitoring is necessary.
From the data collected during the trial dredging, it is
apparent that residue and turbidity approach background values 3,300
feet behind the dredge. The Division of Water Quality is also aware
that the quantity of material to be dredged in Wilmington Harbor is
much less than the quantity dredged in a hopper dredge overflow
operation in Chesapeake Bay (Nichols et al. 1990). However, we are
still concerned that the lateral migration and subsequent
redeposition would adversely effect benthic assemblages in areas
adjacent to the channel, which are classified as Primary Nursery
Areas (PNAs). Our concerns can be summarized as follows:
1) During DWQ's March 27, 1997 field visit aboard the hopper dredge
McFarland, no residue or turbidity sampling of the sediment plume was
made to determine its lateral extent beyond the channel axis.
2) Nichols et al. (1990) found that the sediment plume width
increases with age. Seven (7) minutes after the dredge passes, the
near field zone width is narrow (ca. 140 m). However, 63 minutes
after the dredge pass, the near field width of the sediment plume
increases to > 1, 100 m (Nichols et al. 1990). The PNA of concern
near the channel axis in Wilmington Harbor is only some 300 meters
away.
3) The Nichols et al. study site had a northwest current component.
The greatest extent of sediment plume propagation (other than that
from directly behind the dredge) occurred in the southwest direction.
Yet despite the northwest current, a sediment plume still extended
over 300m from the dredge track in the northeastern direction
(Nichols et al. 1990).
Mr. W. Coleman Long
Wilmington Corps of Engineers
Wilmington Harbor Dredging
4) The overwhelming majority of studies regarding dredging have been
focused chiefly on disposal sites. There are few data pertaining to
the dispersion of suspended sediment and the impact of sediment
accumulation around dredge sites (Nichols et al. 1990). This is most
notably true for the dispersion of sediment discharged by hopper
overflow (Nichols et al. 1990). Nichols et al. (1990) goes on further
to state that a notable exception (Sustar et al. 1976) dealt with
hopper dredging in San Francisco Bay. However, the Sustar et al.
study showed that the resuspension and rate of dispersion of sediment
is dependent on the dredge and duration of water-sediment
interactions. Consequently (and importantly), the information is site
specific (Nichols et al. 1990).
5) In a literature review of recovery times for benthic communities
after dredging in Chesapeake Bay, Nichols et al. (1990) found that
the recovery times for benthic communities range from within months
to a year and a half depending on community type. Furthermore,
Nichols et al. (1990) determined that intercomparison of the data
from these studies (15 in all) is difficult and that the results are
mainly site specific. Nichols et al. (1990) summarize by stating that
these studies do provide a useful first order understanding of the
range of environmental effect dredging has in Chesapeake Bay but the
environmental risks of dredging cannot be predicted with certainty
because quantitative field data are lacking.
For these reasons DWQ believes that it is reasonable to require
USACOE to undertake the additional monitoring efforts as outlined in
the attached 401 Certification. Since there was no sampling of the
sediment plume laterally during the hopper overflow, and the Nichols
et al. study demonstrated lateral flow and deposition with this type
of dredging, there is no evidence that sediment will remain in the
400 foot wide channel limits. Considering the aforementioned points,
DWQ believes that the monitoring with resultant action in respect to
the scope of dredging is justified to protect water quality standards
and the nearby PNAs.
If you should have any questions regarding the content of this
letter please feel free to call me at [phone].
Sincerely,
John R. Dorney
Water Quality Certification Program
Cc: Frank Yelverton, USACOE-Wilmington District Office
John Parker, N.C. Division of Coastal Management
Rick Shiver, DWQ-Wilmington Regional Office
State of North Carolina
Department of Environment, `
ealth and Natural Resources
vision of Water Quality
J mes B. Hunt, governor
J nat atha n B. Howes. Secretary
Preston Howard, Jr.. P.E., Director
V < SQ, F
July 31, 1997
Mr. W. Coleman Long
Wilmington District Corps of Engineers s
Environmental Resources Section
P.O. Box 1890
Wilmington, NC 28402-1890
Dear Mr. Long:
1?4 RE: 401 Water Quality Certification
Hopper dredge-with overflow - Wilmington Harbor dredging
New Hanover County
DWQ # 970625
On 14 July 1997, DWQ staff received your application for use of a hopper dredge with
overflow to facilitate the dredging of Wilmington Harbor. In accordance with 15A NCAC 2H
JJ .0503, an Individual Certification will be needed for this project. I have put the project out to
Public Notice for this purpose. Until the Public Notice process is complete, this project will have
of to remain on hold. The public comment period is for 15 days after publication in the local
newspaper.
Also in accordance with the Memorandum of Agreement with our agencies, we have
completed our review of the Certification application and EA and have the following comments.
We expect that these conditions will need to be included in the 401 Certification in order to
protect water quality. If these conditions (or modifications thereof based on your review) are
included in the Certification, we anticipate issuing the 401 Certification after the EA/FONSI is
completed. ?a-4'ex?„Q
1. If dredgin done in locations with less than 90% sand, water quality data shall be
collected by the . Army Corps of Engineers for total and suspended residue and turbidity to
determine the r extent of the sediment plumeias well as the extent and thickness of the
sediment redeposition on the channel flanks. \kt a n vf; W'ar? NmsCv *v' (PN??
The effect of sediment redeposition on benthic organisms adjacent to the channel shall
be documented by the U.S. Corps of Engineers by monitoring pre and post benthic abundance and
diversity in areas adjacent to the channel here redeposition is observed.
Division of Water Qu ity - Environmental Sciences Branch
Environmental Sciences Branch, 4401 Reedy reek Rd., Raleigh, NC 27607 Telephone [phone] FAX [phone]
An Equal Opportunity Affirmative Acti n Employer • 500% recycled110% post consumer paper L
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L State of North Carolina
Department of Environment, LTN?FA
Health and Natural Resources 4 J •
Division of Water Quality
James Hunt, Governor p E H N F=1
Jonathan B. Howes, Secretary
A. Preston Howard, Jr., P.E., Director
July 31, 1997
Mr. W. Coleman Long
Wilmington District Corps of Engineers
Environmental Resources Section
P.O. Box 1890
-Wilmington, NC 28402-1890
Dear Mr. Long:
RE: 401 Water Quality Certification
Hopper dredge with overflow - Wilmington Harbor dredging
New Hanover County
DWQ # 970625
On 14 July 1997, DWQ staff received your application for use of a hopper dredge with
overflow to facilitate the dredging of Wilmington Harbor. In accordance with 15A NCAC 2H
.0503, an Individual Certification will be needed for this project. I have put the project out to
Public Notice for this purpose. Until the Public Notice process is complete, this project will have
to remain on hold. The public comment period is for 15 days after publication in the local
newspaper.
Also in accordance with the Memorandum of Agreement with our agencies, we have
completed our review of the Certification application and EA and have the following comments.
We expect that these conditions will need to be included in the 401 Certification in order to
protect water quality. If these conditions (or modifications thereof based on your review) are
included in the Certification, we anticipate issuing the 401 Certification after the EA/FONSI is
completed.
1. If dredging is done in locations with less than 90% sand, water quality data shall be
collected by the U.S. Army Corps of Engineers for total and suspended residue and turbidity to
determine the later extent of the sediment plume as well as the extent and thickness of the
sediment redeposition on the channel flanks.
2. The effect of sediment redeposition on benthic organisms adjacent to the channel shall
be documented by the U.S. Corps of Engineers by monitoring pre and post benthic abundance and
diversity in areas adjacent to the channel where redeposition is observed.
Division of Water Quality - Environmental Sciences Branch
Environmental Sciences Branch, 4401 Reedy Creek Rd., Raleigh, NC 27607 Telephone [phone] FAX # [phone]
An Equal Opportunity Affirmative Action Employer • 50% recycled/10% post consumer paper
3. The water chemistry and benthic sampling methodologies shall be reviewed and
approved by DWQ after review by other appropriate agencies. Written approval for this plan is
required from DWQ before the use of the hopper dredge with overflow is implemented.
4. If results from the water quality and benthic monitoring reveal significant
environmental impacts, the 401 Certification may be modified to reflect those impacts. Similarly
if the monitoring reveals a lack of environmental impact, the Certification may be modified to
remove those monitoring requirements.
Please call me at 919-733-1786 if you have any questions about these conditions or
suggestions to make them more praticaL
urs,
S' PDomeyq
Jo Water Quality Certification g ram
cc: Jim Gregson, DWQ Wilmington Regional Office
Steve Benton, DCM
Central Files
970625.com
~ .-
State of North Carolina
Department of Environment, L,
Health and Natural Resources
Division of Water Quality
James Hunt, Governor ED E
Jonathan B. Howes, Secretary
A. Preston Howard, Jr., P.E., Director
August 1, 1997
Wilmington Star-News
P.O. Box 840
Wilmington, NC 28402
Attn: Legal Ad Department
Dear Sir:
Re: Public Notices
Please publish the attached Public Notice one time in the section set aside for Legal
Advertisements in your newspaper. The publication should run on or before August 5, 1997.
Please send the invoice for publication and three copies of the affidavit of publication to the address
given below. Payment cannot be processed without the affidavit of publication.
N.C. Division of Water Quality
Water Quality Section
4401 Reedy Creek Road
Raleigh, NC 27607
Attn: John Domey
If you have any questions concerning this matter, please call John Dorney at 919-733-1786.
Sincerely,
Jqhn R. Dorney
ater Quality C cation Program
cc: John Dorney
Wilmington DWQ Regional Office
Central Files
Coleman Long, U.S. Army Corps of Engineers
970625.pub
Division of Water Quality - Environmental Sciences Branch
4401 Reedy Creek Rd., Raleigh, NC 27626-0535 - Telephone [phone] - FAX [phone]
An Equal Opportunity Affirmative Action Employer50% recycled/ 10% post-consumer paper
NORTH CAROLINA DIVISION OF WATER QUALITY
PUBLIC NOTICE is hereby given that the U.S. Army Corps of Engineers, North Carolina, has
applied to the North Carolina Division of Water Quality for a Water Quality Certification pursuant
to Section 401 of the Federal Clean Water Act and Water Quality Commission rules in 15A NCAC
2H .0101 AND 15A NCAC 2B .0220. The activity for this the certification is sought is to utilize a
hopper dredge with overflow as an additional maintenance dredging method for portions of the
Wilmington Harbor dredging project, in New Hanover County.
The public is invited to comment on the above mentioned application to the Division of Water
Quality. Comments shall be in writing and shall be received by the Division no later than August
22, 1997. DWQ is proposing to take final action upon receipt of the final Environmental
Assessment from the U. S. Army Corps of Engineers. Comments should be sent to N.C.
Division of Water Quality, Environmental Sciences Branch, 4401 Reedy Creek Road, Raleigh,
North Carolina 27607, Attention: John Dorney [phone] Fax: [phone]. A copy of
the application is on file at the Division office at 127 Cardinal Drive Ext., Wilmington, North
Carolina 28405-3845 (Wilmington Regional Office 910-395-3900; Fax #[phone]) during
normal business hours and may be inspected by the public.
eston Howard, Jr.
for
C. Division of Wa Quality
DATE: 1 August 1997

NORTH CAROLINA DIVISION OF WATER QUALITY
Water Quality Section
Wilmington Regional Office
Date: July 25, 1997
To: Melba McGee
FYom: James H. Gregso40____
Through: Rick Shiver -? S
Subject: A95 Review
Environmental Assessment
Use of Hopper Dredge With Overflow
US Army Corps of Engineers
Project Number 98-0037
New Hanover County
The Wilmington District Corps of Engineers proposes to use hopper dredging with
overflow in the Cape Fear River from the mouth of the Brunswick River downstream in areas
where hopper dredging with overflow is currently not allowed. Hopper dredging with overflow
is currently excluded in the following reaches: Keg Island, Lower Lilliput, and Lower and Upper
Midnight. Overflow has not been allowed in these areas due to the quality of the sediments
(greater than 10 percent fines). All disposal from hopper dredging would be in the EPA
Wilmington Ocean Dredged Material Disposal Site. Hopper dredging with overflow is being
proposed in these additional areas in order to allow dredges to obtain a more economic load and
to provide a more efficient means of dredging in areas of the river where upland disposal areas
lack sufficient capacity or when other disposal options may not be available during emergencies.
On March 7, 1997, staff from the Division of Water Quality participated in a field trip
aboard the hopper dredge MCFARLAND along with other State and Federal review agencies.
The purpose of the field trip was to observe the operation of the MCFARLAND during overflow
and to discuss the concerns of various agencies over the overflow operation.
On March 27, 1997, staff from the Division of Water Quality participated in another field
trip in cooperation with the Wilmington District Corps of Engineers to monitor the overflow from
the hopper dredge MCFARLAND. Water samples were collected during two overflow events and
analyzed for total and suspended residue and turbidity. Physical measurements were taken for
salinity, dissolved oxygen, and temperature. Water samples and physical measurements were
taken at the surface (0.3 meters), mid-depth (7 meters), and near-bottom (11 meters). For each
overflow event, samples were collected at the three depths at multiple distances behind the dredge,
up to 3,300 feet for the overflow of Lower Midnight Channel sediments and up to 1,600 feet for
Melba McGee
July 25, 1997
Page Three
2. • That the effect of sediment redeposition on benthic assemblages adjacent to the
channel be evaluated by monitoring pre dredging benthic abundance and diversity
adjacent to the channel and monitoring post dredging benthic diversity and
abundance in areas where redeposition is observed.
3. That data collection and sampling methodologies will be coordinated with the
Division of Water Quality (DWQ) and other appropriate review agencies. That
monitoring results will be reviewed by DWQ to determine if environmental
impacts associated with hopper dredge overflow should result in rescission of the
401 Certification by the Director.
cc: Wilmington Regional Office Files
Central Files
John Dorney
Steve Benton
J RF?Fi,1F,6
U
g
/F
4sc
NCFs
State of North Carolina
Department of Environment,
Health and Natural Resources
Division of Coastal Management
James B. Hunt, Jr., Governor
Jonathan B. Howes, Secretary
Roger N. Schecter, Director
07/16/97
Mr. Jim Gregson
NC DEN&NR
Division of Water Quality
127 Cardinal Drive
Wilmington, NC 28405
JEEL
AkT*9
C)EHNR
REFERENCE: CD97-26 County: New Hanover
Applicant/Sponsor: U.S. Army Corps of Engineers
EA: Use of Hopper Dredge with Overflow, Wilmington Harbor
Dear Mr. Gregson:
The attached Consistency Determination, dated 07111197
describing a proposed Federal Activity is being circulated to
State agencies for comments concerning the proposal's consistency
with the North Carolina Coastal Management Program.
Please indicate your viewpoint
form to me before 08105197
on the proposal and return this
Sin rely,
tep en B. Benton
Consistency Coordinator
REPLY his office objects to the project as proposed.
Comments on this project are attached.
This office supports the project proposal.
No comment.
Signed
Date 19 V
Agency ??..102
P.O. Box 27687, Raleigh, North Carolina 27611-7687 Telephone [phone] FAX [phone]
An Equal Opportunity Affirmative Action Employer 50% recycled/ 10% post-consumer paper
K ^?`"'17?;r. DEPARTMENT OF THE ARMY
WILMINGTON DISTRICT, CORPS OF ENGINEERS
PO. BOX 1890
WILMINGTON, NORTH CAROLINA 28402-1890
IN REPLY REFER TO July 11, 1997
Environmental Resources Section
Dear Sir or Madam:
Enclosed for your review and comments is a copy(s) of the Environmental
Assessment (EA), Use of Hopper Dredge with Overflow as an Additional
Maintenance Dredoinq Method for Portions of Wilminqton Harbor, North
Carolina. This EA has been prepared in accordance with the Council on
Environmental Quality (40 CFR 1500-1508) and the U.S. Army Corps of
Engineers regulations (33 CFR 230) for implementing the National
Environmental Policy Act of 1969, as amended.
The primary purpose of this EA is to discuss the need for and impacts of
using a hopper dredge with overflow for maintenance of Wilmington Harbor
downstream of the mouth of the Brunswick River. The EA indicates that hopper
dredging is more efficient with overflow than without overflow. Hopper dredging
with overflow should not adversely impact the environment.
Please provide any comments you may have by August 15, 1997. If you
have any questions concerning this matter, please contact Mr. Frank Yelverton,
Environmental Resources Section, at [phone].
Sincerely,
l/?J
11'1`
-PM- C. E. Shuford, Jr., P. E.
Acting Chief, Engineering
and Planning Division
Enclosure
DEPARTMENT OF THE ARMY
WILMINGTON DISTRICT, CORPS OF ENGINEERS
P.O. BOX 1890
t WILMINGTON, NORTH CAROLINA 28402-1890
?July 11, 1997
IN REPLY REFER TO 9 VJ Of) 5
Environmental Resources Section
Mr. John Dorneyo rSS " . R?c???FG
Division of Water Quality
North Carolina Department of Environment, 7y9
]
and Natural Resources 'rNTq4
4401 Reedy Creek Road
Raleigh, North Carolina 27607-6445
Dear Mr. Dorney:
have enclosed an Application For 401 Water Quality Certification, pursuant to
Section 401 of Public Law 95-217, for use of a hopper dredge with overflow as an
additional maintenance dredging method for portions of Wilmington Harbor, North
Carolina. The environmental assessment for the proposed action is also enclosed.
Messrs. Jim Gregson and Greg Price with your Division have been involved in field
trips and discussions on this project.
Should you have any questions concerning the application, please contact
Mr. Frank Yelverton, Environmental Resources Section, at [phone].
Sincerely,
C? 1?47_
-?V,C. E. Shuford, Jr., P.E.
Acting Chief, Engineering and
Planning Division
Enclosure (7 copies)
Copy Furnished:
Mr. Jim Gregson
Division of Water Quality
North Carolina Department of Environment,
and Natural Resources
127 Cardinal Drive Extension
Wilmington, North Carolina 28405-3845
U.S. ARMY CORPS OF ENGINEERS
APPLICATION FOR 401 WATER QUALITY CERTIFICATION
DATE: June 18, 1997
2. NAME/ADDRESS: U.S. Army Corps of Engineers
Wilmington District
Post Office Box 1890
Wilmington, North Carolina 28402-1890
3. RESPONSIBLE INDIVIDUAL: Terry R. Youngbluth
Colonel, U.S. Army
District Engineer
4. NAME OF CORPS OF ENGINEERS CONTACT: Frank Yelverton
TELEPHONE NUMBER: [phone]
5. TYPE OF APPLICATION: New Application
6. PROJECT NAME: Maintenance of Wilmington Harbor
7. DESCRIPTION OF PROPOSED WORK: Wilmington Harbor is an
approximately 38-mile Federal navigation project located along the Cape Fear and
Northeast Cape Fear Rivers in southeastern North Carolina (Figure 1). In the Cape
Fear River below the mouth of the Brunswick River, the Wilmington Harbor Federal
Channel is 400 feet wide by 38 feet deep. Maintenance dredging in Wilmington Harbor
using a hopper dredge is allowed from Lower Big Island Channel downstream
(Figure 1), but in the river overflow is only allowed in areas that are generally greater
than 95 percent sand (but at least 90 percent sand). Excluded from overflow are 7.9
miles of the following channels (less than 90 percent sand): Keg Island, Lower Lilliput
and Lower and Upper Midnight. The proposed action would involve hopper dredging
with overflow in all these reaches. In addition, the use of hopper dredging with
overflow is proposed to extend 2.9 miles upstream from Lower Big Island Channel to
the mouth of the Brunswick River. This extension contains Upper Big Island and Lower
and Upper Brunswick Channels, which are mostly greater than 90 percent sand.
Including this 2.9-mile extension and 7.9-mile length indicated above, a total of 10.8
miles of channel would be added to the hopper dredging with overflow maintenance
method. All disposal would be in the Wilmington Harbor Ocean Dredged Material
Disposal Site (ODMDS) located about 3 miles offshore of the mouth of the Cape Fear
River in accordance with Section 103 of the Marine Protection Research and
Sanctuaries Act of 1972, as amended (MPRSA 1972).
Currently, maintenance in the Cape Fear River from Lower Big Island Channel
downstream is usually performed by a bucket and barge dredge with disposal in the
ODMDS and from Upper Big Island upstream maintenance is performed by a hydraulic
pipeline dredge with disposal in the Eagle Island diked upland disposal facility
(Figure 1).
The 10.8 miles of channels where hopper dredging and/or overflow is proposed
for the first time, are currently maintained and are anticipated to be maintained on a 2-4
year frequency. The average annual volume to be removed from these channels is
about 320,000 cubic yards.
The proposed action is described in detail in the environmental assessment (EA)
Use of a Hopper Dredge with Overflow as a Maintenance Dredging Method for Portions of
Wilmington Harbor, North Carolina, July 1997.
8. PURPOSE OF PROPOSED WORK: Hopper dredging with overflow is more
efficient than hopper dredging without overflow and should not adversely impact the
environment.
9. PROPOSED ACTIVITY TO BEGIN: Fall 1997
10. DURATION OF ACTIVITY: 1-4 months each year
11. DISCHARGE OF:
X Dredged Material (overflow from a hopper dredge)
Fill Material
12. LOCATION OF DISCHARGE:
Municipality: Wilmington, North Carolina
County: New Hanover and Brunswick
Drainage Basin: Cape Fear
Receiving Waters: Cape Fear River
13. NATURE OF RECEIVING WATERS:
Type: Coastal
Nature: Salt
Direction of Flow: Variable due to tides
14. TYPE OF DISCHARGE INCLUDING CHEMICAL COMPOSITION: Samples of
bottom sediments from a representative channel (Keg Island) were collected in 1992 and
tested to evaluate the toxicity and bioaccumulation potential of chemical contaminants
which may be associated with those maintenance sediment materials (Ward et al. 1993).
These site specific test results indicate that the maintenance sediments meet the testing
criteria of the Environmental Protection Agency's Ocean Dumping Regulations and Criteria
and are, therefore, acceptable for transportation for ocean dumping under Section 103 of
the Marine Protection, Research, and Sanctuaries Act of 1972, as amended. Chemical
test were again performed on sediment samples taken in 1996 from the Keg Island
Channel. The results of these tests also indicate that the sediments are acceptable for
ocean disposal (USACE 1997). Based on these results, the maintenance material is not
considered to be contaminated.
As indicated in the EA, turbidity and suspended sediments associated with such
overflow should be not adversely impact the environment.
15. PROJECTED FUTURE VARIATION IN THE NATURE OF THE DISCHARGE:
None.
16. IS THIS PROJECT LOCATED IN A WATERSHED CLASSIFIED AS SA, HQW, OR
ORW?
_YES (circle one) X NO, not in the area upstream of Snows Marsh
where overflow is proposed for the first time.
17. NUMBER OF ACRES OR VOLUME OF WETLANDS IMPACTED BY THE
PROPOSED PROJECT:
Filled: None
Excavated: None
Total Impacted: None
18. STATE REASONS WHY THE APPLICANT BELIEVES THAT THIS ACTIVITY
MUST BE CARRIED OUT AS PLANNED. ALSO, NOTE MEASURES TAKEN TO
MINIMIZE WETLAND IMPACTS: See 7, 8, and 17 above.
19. HAVE ANY SECTION 401 CERTIFICATES BEEN PREVIOUSLY REQUESTED
FOR USE ON THIS PROPERTY?
X YES NO IF YES, EXPLAIN:
Several Section 401 certificates have been issued for projects in Wilmington Harbor. They
include:
a. No. 1627R issued 12/21/89 - Maintenance of Wilmington Harbor,
renourishing bird islands
b. No. 2452 issued 4/17/90 - Long-term maintenance of Wilmington Harbor
C. No. 2971 issued 2/8/95 - Wilmington Harbor Channel Widening
d. No. 3084 issued 10/16/96 - Cape Fear - Northeast Cape Fear Rivers
Comprehensive Study.
I certify that all information contained herein or in support thereof is true and correct
to the best of my knowledge.
A 2-W
C. E. Shuford, Jr., P.E.
Acting Chief, Engineering and
Planning Division
DATE: u d ?9
Reference:
U.S. Army Corps of Engineers, Wilmington District. 1997. Tier I Evaluation of Dredge
Material Proposed for Ocean Disposal, Wilmington Harbor and Military Ocean
Terminal, Sunny Point, North Carolina.
Ward, J. A., M. R. Pinza, M. E. Barrows, and J. Q. Word. 1993. Ecological Evaluation
of Proposed Dredged Material From Wilmington Harbor and Military Ocean Terminal,
Sunny Point, North Carolina. Prepared for the U.S. Army Corps of Engineers, North
Carolina District, Under a Related Services Agreement with the U.S. Department of
Energy Contract DE-AC06-76RLO 1830 by Battelle, Pacific Northwest Laboratory,
Richland, Washington 99352

U.S. ARMY CORPS OF ENGINEERS
APPLICATION FOR 401 WATER QUALITY CERTIFICATION
DATE: June 18, 1997
2. NAME/ADDRESS: U.S. Army Corps of Engineers
Wilmington District
Post Office Box 1890
Wilmington, North Carolina 28402-1890 °ti???9 k? Jyy/
3. RESPONSIBLE INDIVIDUAL: Terry R. Youngbluth
Colonel, U.S. Army ?
District Engineer
4. NAME OF CORPS OF ENGINEERS CONTACT: Frank Yelverton
TELEPHONE NUMBER: [phone]
5. TYPE OF APPLICATION: New Application
6. PROJECT NAME: Maintenance of Wilmington Harbor
7. DESCRIPTION OF PROPOSED WORK: Wilmington Harbor is an
approximately 38-mile Federal navigation project located along the Cape Fear and
Northeast Cape Fear Rivers in southeastern North Carolina (Figure 1). In the Cape
Fear River below the mouth of the Brunswick River, the Wilmington Harbor Federal
Channel is 400 feet wide by 38 feet deep. Maintenance dredging in Wilmington Harbor
using a hopper dredge is allowed from Lower Big Island Channel downstream
(Figure 1), but in the river overflow is only allowed in areas that are generally greater
than 95 percent sand (but at least 90 percent sand). Excluded from overflow are 7.9
miles of the following channels (less than 90 percent sand): Keg Island, Lower Lilliput
and Lower and Upper Midnight. The proposed action would involve hopper dredging
with overflow in all these reaches. In addition, the use of hopper dredging with
overflow is proposed to extend 2.9 miles upstream from Lower Big Island Channel to
the mouth of the Brunswick River. This extension contains Upper Big Island and Lower
and Upper Brunswick Channels, which are mostly greater than 90 percent sand.
Including this 2.9-mile extension and 7.9-mile length indicated above, a total of 10.8
miles of channel would be added to the hopper dredging with overflow maintenance
method. All disposal would be in the Wilmington Harbor Ocean Dredged Material
Disposal Site (ODMDS) located about 3 miles offshore of the mouth of the Cape Fear
River in accordance with Section 103 of the Marine Protection Research and
Sanctuaries Act of 1972, as amended (MPRSA 1972).
Currently, maintenance in the Cape Fear River from Lower Big Island Channel
downstream is usually performed by a bucket and barge dredge with disposal in the
ODMDS and from Upper Big Island upstream maintenance is performed by a hydraulic
pipeline dredge with disposal in the Eagle Island diked upland disposal facility
(Figure 1).
The 10.8 miles of channels where hopper dredging and/or overflow is proposed
for the first time, are currently maintained and are anticipated to be maintained on a 2-4
year frequency. The average annual volume to be removed from these channels is
about 320,000 cubic yards.
The proposed action is described in detail in the environmental assessment (EA)
Use of a Hopper Dredge with Overflow as a Maintenance Dredging Method for Portions of
Wilmington Harbor, North Carolina, July 1997.
8. PURPOSE OF PROPOSED WORK: Hopper dredging with overflow is more
efficient than hopper dredging without overflow and should not adversely impact the
environment.
9. PROPOSED ACTIVITY TO BEGIN: Fall 1997
10. DURATION OF ACTIVITY: 1-4 months each year
11. DISCHARGE OF:
X Dredged Material (overflow from a hopper dredge)
Fill Material
12. LOCATION OF DISCHARGE:
Municipality: Wilmington, North Carolina
County: New Hanover and Brunswick
Drainage Basin: Cape Fear
Receiving Waters: Cape Fear River
13. NATURE OF RECEIVING WATERS:
Type: Coastal
Nature: Salt
Direction of Flow: Variable due to tides
14. TYPE OF DISCHARGE INCLUDING CHEMICAL COMPOSITION: Samples of
bottom sediments from a representative channel (Keg Island) were collected in 1992 and
tested to evaluate the toxicity and bioaccumulation potential of chemical contaminants
which may be associated with those maintenance sediment materials (Ward et al. 1993).
These site specific test results indicate that the maintenance sediments meet the testing
criteria of the Environmental Protection Agency's Ocean Dumping Regulations and Criteria
and are, therefore, acceptable for transportation for ocean dumping under Section 103 of
the Marine Protection, Research, and Sanctuaries Act of 1972, as amended. Chemical
test were again performed on sediment samples taken in 1996 from the Keg Island
Channel. The results of these tests also indicate that the sediments are acceptable for
ocean disposal (USACE 1997). Based on these results, the maintenance material is not
considered to be contaminated.
As indicated in the EA, turbidity and suspended sediments associated with such
overflow should be not adversely impact the environment.
15. PROJECTED FUTURE VARIATION IN THE NATURE OF THE DISCHARGE:
None.
16. IS THIS PROJECT LOCATED IN A WATERSHED CLASSIFIED AS SA, HQW, OR
ORW?
_YES (circle one) X NO, not in the area upstream of Snows Marsh
where overflow is proposed for the first time.
17. NUMBER OF ACRES OR VOLUME OF WETLANDS IMPACTED BY THE
PROPOSED PROJECT:
Filled: None
Excavated: None
Total Impacted: None
18. STATE REASONS WHY THE APPLICANT BELIEVES THAT THIS ACTIVITY
MUST BE CARRIED OUT AS PLANNED. ALSO. NOTE MEASURES TAKEN TO
MINIMIZE WETLAND IMPACTS: See 7, 8, and 17 above.
19. HAVE ANY SECTION 401 CERTIFICATES BEEN PREVIOUSLY REQUESTED
FOR USE ON THIS PROPERTY?
X YES NO IF YES, EXPLAIN:
Several Section 401 certificates have been issued for projects in Wilmington Harbor. They
include:
a. No. 1627R issued 12/21/89 - Maintenance of Wilmington Harbor,
renourishing bird islands
b. No. 2452 issued 4/17/90 - Long-term maintenance of Wilmington Harbor
C. No. 2971 issued 2/8/95 - Wilmington Harbor Channel Widening
d. No. 3084 issued 10/16/96 - Cape Fear - Northeast Cape Fear Rivers
Comprehensive Study.
I certify that all information contained herein or in support thereof is true and correct
to the best of my knowledge.
c
W` 002W
C. E. Shuford, Jr., P.E.
Acting Chief, Engineering and
Planning Division
DATE: 7Jt4 1177
Reference:
U.S. Army Corps of Engineers, Wilmington District. 1997. Tier I Evaluation of Dredge
Material Proposed for Ocean Disposal, Wilmington Harbor and Military Ocean
Terminal, Sunny Point, North Carolina.
Ward, J. A., M. R. Pinza, M. E. Barrows, and J. Q. Word. 1993. Ecological Evaluation
of Proposed Dredged Material From Wilmington Harbor and Military Ocean Terminal,
Sunny Point, North Carolina. Prepared for the U.S. Army Corps of Engineers, North
Carolina District, Under a Related Services Agreement with the U.S. Department of
Energy Contract DE-AC06-76RLO 1830 by Battelle, Pacific Northwest Laboratory,
Richland, Washington 99352

U.S. ARMY CORPS OF ENGINEERS
APPLICATION FOR 401 WATER QUALITY CERTIFICATION
1. DATE: June 18, 1997
2. NAME/ADDRESS: U.S. Army Corps of Engineers
Wilmington District F? ??
Post Office Box 1890 Goo
Wilmington, North Carolina 28402-1890 ti??yfq(s
3. RESPONSIBLE INDIVIDUAL: Terry R. Youngbluth
Colonel, U.S. Army
District Engineer
4. NAME OF CORPS OF ENGINEERS CONTACT: Frank Yelverton
TELEPHONE NUMBER: [phone]
5. TYPE OF APPLICATION: New Application
6. PROJECT NAME: Maintenance of Wilmington Harbor
7. DESCRIPTION OF PROPOSED WORK: Wilmington Harbor is an
approximately 38-mile Federal navigation project located along the Cape Fear and
Northeast Cape Fear Rivers in southeastern North Carolina (Figure 1). In the Cape
Fear River below the mouth of the Brunswick River, the Wilmington Harbor Federal
Channel is 400 feet wide by 38 feet deep. Maintenance dredging in Wilmington Harbor
using a hopper dredge is allowed from Lower Big Island Channel downstream
(Figure 1), but in the river overflow is only allowed in areas that are generally greater
than 95 percent sand (but at least 90 percent sand). Excluded from overflow are 7.9
miles of the following channels (less than 90 percent sand): Keg Island, Lower Lilliput
and Lower and Upper Midnight. The proposed action would involve hopper dredging
with overflow in all these reaches. In addition, the use of hopper dredging with
overflow is proposed to extend 2.9 miles upstream from Lower Big Island Channel to
the mouth of the Brunswick River. This extension contains Upper Big Island and Lower
and Upper Brunswick Channels, which are mostly greater than 90 percent sand.
Including this 2.9-mile extension and 7.9-mile length indicated above, a total of 10.8
miles of channel would be added to the hopper dredging with overflow maintenance
method. All disposal would be in the Wilmington Harbor Ocean Dredged Material
Disposal Site (ODMDS) located about 3 miles offshore of the mouth of the Cape Fear
River in accordance with Section 103 of the Marine Protection Research and
Sanctuaries Act of 1972, as amended (MPRSA 1972).
Currently, maintenance in the Cape Fear River from Lower Big Island Channel
downstream is usually performed by a bucket and barge dredge with disposal in the
ODMDS and from Upper Big Island upstream maintenance is performed by a hydraulic
pipeline dredge with disposal in the Eagle Island diked upland disposal facility
(Figure 1).
The 10.8 miles of channels where hopper dredging and/or overflow is proposed
for the first time, are currently maintained and are anticipated to be maintained on a 2-4
year frequency. The average annual volume to be removed from these channels is
about 320,000 cubic yards.
The proposed action is described in detail in the environmental assessment (EA)
Use of a Hopper Dredge with Overflow as a Maintenance Dredging Method for Portions of
Wilmington Harbor, North Carolina, July 1997.
8. PURPOSE OF PROPOSED WORK: Hopper dredging with overflow is more
efficient than hopper dredging without overflow and should not adversely impact the
environment.
9. PROPOSED ACTIVITY TO BEGIN: Fall 1997
10. DURATION OF ACTIVITY: 1-4 months each year
11. DISCHARGE OF:
X Dredged Material (overflow from a hopper dredge)
Fill Material
12. LOCATION OF DISCHARGE:
Municipality: Wilmington, North Carolina
County: New Hanover and Brunswick
Drainage Basin: Cape Fear
Receiving Waters: Cape Fear River
13. NATURE OF RECEIVING WATERS:
Type: Coastal
Nature: Salt
Direction of Flow: Variable due to tides
14. TYPE OF DISCHARGE INCLUDING CHEMICAL COMPOSITION: Samples of
bottom sediments from a representative channel (Keg Island) were collected in 1992 and
tested to evaluate the toxicity and bioaccumulation potential of chemical contaminants
which may be associated with those maintenance sediment materials (Ward et al. 1993).
These site specific test results indicate that the maintenance sediments meet the testing
criteria of the Environmental Protection Agency's Ocean Dumping Regulations and Criteria
and are, therefore, acceptable for transportation for ocean dumping under Section 103 of
the Marine Protection, Research, and Sanctuaries Act of 1972, as amended. Chemical
test were again performed on sediment samples taken in 1996 from the Keg Island
Channel. The results of these tests also indicate that the sediments are acceptable for
ocean disposal (USACE 1997). Based on these results, the maintenance material is not
considered to be contaminated.
As indicated in the EA, turbidity and suspended sediments associated with such
overflow should be not adversely impact the environment.
15. PROJECTED FUTURE VARIATION IN THE NATURE OF THE DISCHARGE:
None.
16. IS THIS PROJECT LOCATED IN A WATERSHED CLASSIFIED AS SA, HQW, OR
ORW?
_YES (circle one) X NO, not in the area upstream of Snows Marsh
where overflow is proposed for the first time.
17. NUMBER OF ACRES OR VOLUME OF WETLANDS IMPACTED BY THE
PROPOSED PROJECT:
Filled: None
Excavated: None
Total Impacted: None
18. STATE REASONS WHY THE APPLICANT BELIEVES THAT THIS ACTIVITY
MUST BE CARRIED OUT AS PLANNED. ALSO, NOTE MEASURES TAKEN TO
MINIMIZE WETLAND IMPACTS: See 7, 8, and 17 above.
19. HAVE ANY SECTION 401 CERTIFICATES BEEN PREVIOUSLY REQUESTED
FOR USE ON THIS PROPERTY?
X YES NO IF YES, EXPLAIN:
Several Section 401 certificates have been issued for projects in Wilmington Harbor. They
include:
a. No. 1627R issued 12/21/89 - Maintenance of Wilmington Harbor,
renourishing bird islands
b. No. 2452 issued 4/17/90 - Long-term maintenance of Wilmington Harbor
C. No. 2971 issued 2/8/95 - Wilmington Harbor Channel Widening
d. No. 3084 issued 10/16/96 - Cape Fear - Northeast Cape Fear Rivers
Comprehensive Study.
I certify that all information contained herein or in support thereof is true and correct
to the best of my knowledge.
c v C. E. Shuford, Jr., P.E.
Acting Chief, Engineering and
Planning Division
DATE: 7JL,
Reference:
U.S. Army Corps of Engineers, Wilmington District. 1997. Tier I Evaluation of Dredge
Material Proposed for Ocean Disposal, Wilmington Harbor and Military Ocean
Terminal, Sunny Point, North Carolina.
Ward, J. A., M. R. Pinza, M. E. Barrows, and J. Q. Word. 1993. Ecological Evaluation
of Proposed Dredged Material From Wilmington Harbor and Military Ocean Terminal,
Sunny Point, North Carolina. Prepared for the U.S. Army Corps of Engineers, North
Carolina District, Under a Related Services Agreement with the U.S. Department of
Energy Contract DE-AC06-76RLO 1830 by Battelle, Pacific Northwest Laboratory,
Richland, Washington 99352

U.S. ARMY CORPS OF ENGINEERS
APPLICATION FOR 401 WATER QUALITY CERTIFICATION
1. DATE: June 18, 1997
2. NAME/ADDRESS: U.S. Army Corps of Engineers
Wilmington District .p
Post Office Box 1890
Wilmington, North Carolina 28402-1890 3? ?, < I FO
3. RESPONSIBLE INDIVIDUAL: Terry R. Youngbluth o?lyy?
Colonel, U.S. Army
District Engineer
4. NAME OF CORPS OF ENGINEERS CONTACT: Frank Yelverton
TELEPHONE NUMBER: [phone]
5. TYPE OF APPLICATION: New Application
6. PROJECT NAME: Maintenance of Wilmington Harbor
7. DESCRIPTION OF PROPOSED WORK: Wilmington Harbor is an
approximately 38-mile Federal navigation project located along the Cape Fear and
Northeast Cape Fear Rivers in southeastern North Carolina (Figure 1). In the Cape
Fear River below the mouth of the Brunswick River, the Wilmington Harbor Federal
Channel is 400 feet wide by 38 feet deep. Maintenance dredging in Wilmington Harbor
using a hopper dredge is allowed from Lower Big Island Channel downstream
(Figure 1), but in the river overflow is only allowed in areas that are generally greater
than 95 percent sand (but at least 90 percent sand). Excluded from overflow are 7.9
miles of the following channels (less than 90 percent sand): Keg Island, Lower Lilliput
and Lower and Upper Midnight. The proposed action would involve hopper dredging
with overflow in all these reaches. In addition, the use of hopper dredging with
overflow is proposed to extend 2.9 miles upstream from Lower Big Island Channel to
the mouth of the Brunswick River. This extension contains Upper Big Island and Lower
and Upper Brunswick Channels, which are mostly greater than 90 percent sand.
Including this 2.9-mile extension and 7.9-mile length indicated above, a total of 10.8
miles of channel would be added to the hopper dredging with overflow maintenance
method. All disposal would be in the Wilmington Harbor Ocean Dredged Material
Disposal Site (ODMDS) located about 3 miles offshore of the mouth of the Cape Fear
River in accordance with Section 103 of the Marine Protection Research and
Sanctuaries Act of 1972, as amended (MPRSA 1972).
Currently, maintenance in the Cape Fear River from Lower Big Island Channel
downstream is usually performed by a bucket and barge dredge with disposal in the
ODMDS and from Upper Big Island upstream maintenance is performed by a hydraulic
pipeline dredge with disposal in the Eagle Island diked upland disposal facility
(Figure 1).
The 10.8 miles of channels where hopper dredging and/or overflow is proposed
for the first time, are currently maintained and are anticipated to be maintained on a 2-4
year frequency. The average annual volume to be removed from these channels is
about 320,000 cubic yards.
The proposed action is described in detail in the environmental assessment (EA)
Use of a Hopper Dredge with Overflow as a Maintenance Dredging Method for Portions of
Wilmington Harbor, North Carolina, July 1997.
8. PURPOSE OF PROPOSED WORK: Hopper dredging with overflow is more
efficient than hopper dredging without overflow and should not adversely impact the
environment.
9. PROPOSED ACTIVITY TO BEGIN: Fall 1997
10. DURATION OF ACTIVITY: 1-4 months each year
11. DISCHARGE OF:
X Dredged Material (overflow from a hopper dredge)
Fill Material
12. LOCATION OF DISCHARGE:
Municipality: Wilmington, North Carolina
County: New Hanover and Brunswick
Drainage Basin: Cape Fear
Receiving Waters: Cape Fear River
13. NATURE OF RECEIVING WATERS:
Type: Coastal
Nature: Salt
Direction of Flow: Variable due to tides
14. TYPE OF DISCHARGE INCLUDING CHEMICAL COMPOSITION: Samples of
bottom sediments from a representative channel (Keg Island) were collected in 1992 and
tested to evaluate the toxicity and bioaccumulation potential of chemical contaminants
which may be associated with those maintenance sediment materials (Ward et al. 1993).
These site specific test results indicate that the maintenance sediments meet the testing
criteria of the Environmental Protection Agency's Ocean Dumping Regulations and Criteria
and are, therefore, acceptable for transportation for ocean dumping under Section 103 of
the Marine Protection, Research, and Sanctuaries Act of 1972, as amended. Chemical
test were again performed on sediment samples taken in 1996 from the Keg Island
Channel. The results of these tests also indicate that the sediments are acceptable for
ocean disposal (USACE 1997). Based on these results, the maintenance material is not
considered to be contaminated.
As indicated in the EA, turbidity and suspended sediments associated with such
overflow should be not adversely impact the environment.
15. PROJECTED FUTURE VARIATION IN THE NATURE OF THE DISCHARGE:
None.
16. IS THIS PROJECT LOCATED IN A WATERSHED CLASSIFIED AS SA, HQW. OR
ORW?
_YES (circle one) X NO, not in the area upstream of Snows Marsh
where overflow is proposed for the first time.
17. NUMBER OF ACRES OR VOLUME OF WETLANDS IMPACTED BY THE
PROPOSED PROJECT:
Filled: None
Excavated: None
Total Impacted: None
18. STATE REASONS WHY THE APPLICANT BELIEVES THAT THIS ACTIVITY
MUST BE CARRIED OUT AS PLANNED. ALSO. NOTE MEASURES TAKEN TO
MINIMIZE WETLAND IMPACTS: See 7, 8, and 17 above.
19. HAVE ANY SECTION 401 CERTIFICATES BEEN PREVIOUSLY REQUESTED
FOR USE ON THIS PROPERTY?
X YES NO IF YES, EXPLAIN:
Several Section 401 certificates have been issued for projects in Wilmington Harbor. They
include:
a. No. 1627R issued 12/21/89 - Maintenance of Wilmington Harbor,
renourishing bird islands
b. No. 2452 issued 4/17/90 - Long-term maintenance of Wilmington Harbor
C. No. 2971 issued 2/8/95 - Wilmington Harbor Channel Widening
d. No. 3084 issued 10/16/96 - Cape Fear - Northeast Cape Fear Rivers
Comprehensive Study.

I certify that all information contained herein or in support thereof is true and correct
to the best of my knowledge.
c
C. E. Shuford, Jr., P.E.
Acting Chief, Engineering and
Planning Division
DATE: -7Jt4
Reference:
U.S. Army Corps of Engineers, Wilmington District. 1997. Tier I Evaluation of Dredge
Material Proposed for Ocean Disposal, Wilmington Harbor and Military Ocean
Terminal, Sunny Point, North Carolina.
Ward, J. A., M. R. Pinza, M. E. Barrows, and J. Q. Word. 1993. Ecological Evaluation
of Proposed Dredged Material From Wilmington Harbor and Military Ocean Terminal,
Sunny Point, North Carolina. Prepared for the U.S. Army Corps of Engineers, North
Carolina District, Under a Related Services Agreement with the U.S. Department of
Energy Contract DE-AC06-76RLO 1830 by Battelle, Pacific Northwest Laboratory,
Richland, Washington 99352

0
9"70to)
DEPARTMENT OF THE ARMY
Wilmington District, Corps of Engineers
Post Office Box 1890
Wilmington, North Carolina 28402-1890
401 'SS?
CESAW-EP-PE-97-0011
PUBLIC NOTICE
AND
NOTICE OF AVAILABILITY
ENVIRONMENTAL ASSESSMENT
T6,
,
July 11, 1997
USE OF HOPPER DREDGE WITH OVERFLOW
AS AN ADDITIONAL MAINTENANCE DREDGING METHOD FOR
PORTIONS OF WILMINGTON HARBOR, NORTH CAROLINA
JULY 1997
TO WHOM IT MAY CONCERN:
Wilmington Harbor is an approximately 38-mile Federal navigation project located along
the Cape Fear and Northeast Cape Fear Rivers in southeastern North Carolina (Figure 1). In
the Cape Fear River below the mouth of the Brunswick River, the Wilmington Harbor Federal
Channel is 400 feet wide by 38 feet deep. Maintenance dredging in Wilmington Harbor using
a hopper dredge is currently allowed from Lower Big Island Channel downstream (Figure 1),
but in the river overflow of water from the hopper in order to obtain an economic load is only
allowed in areas that are generally greater than 95 percent sand (but at least 90 percent).
Excluded from overflow are 7.9 miles of the following channels (less than 90 percent sand):
Keg Island, Lower Lilliput and Lower and Upper Midnight. The proposed action would involve
hopper dredging with overflow in all these reaches. In addition, the use of hopper dredging
with overflow is proposed to extend 2.9 miles upstream from Lower Big Island Channel to the
mouth of the Brunswick River. This extension contains Upper Big Island and Lower and Upper
Brunswick Channels, which are mostly greater than 90 percent sand. Including this 2.9-mile
extension and 7.9-mile length indicated above, a total of 10.8 miles of channel would be added
to hopper dredging with overflow maintenance method. All disposal would be in the
Wilmington Ocean Dredged Material Disposal Site (ODMDS) located beyond 3 miles offshore
of the mouth of the Cape Fear River [in accordance with Section 103 of the Marine Protection
Research and Sanctuaries Act of 1972, as amended (MPRSA 1972)].
The 10.8 miles of channels where hopper dredging and/or overflow is proposed for the
first time are currently maintained and are anticipated to be maintained on a 2-4 year
frequency. The average annual volume to be removed from these channels is about 320,000
cubic yards.
The Wilmington Harbor environment is discussed in detail in the following three final
environmental impact statements (FEIS). The environmental assessment (EA) described in this
notice only adds information concerning the monitoring data collected March 27, 1997, during
the test overflow of the hopper dredge MCFARLAND:
1. U.S. Army Corps of Engineers, Wilmington District. October 1989. Final
Environmental Impact Statement, Long-Term Maintenance of Wilmington Harbor, North
Carolina.
2. U.S. Army Corps of Engineers, Wilmington District. June 1996. Final Feasibility
Report and Environmental Impact Statement, on Improvement of Navigation, Cape Fear-
Northeast Cape Fear Rivers Comprehensive Study, Wilmington, North Carolina.
3. U.S. Environmental Protection Agency, Region IV. October 1983. Final
Environmental Impact Statement, Savannah, Georgia; Charleston, South Carolina; and
Wilmington, North Carolina, Ocean Dredged Material Disposal Site Designation.
A Section 401 (P.L. 95-217) Water Quality Certificate is required for overflow of the
hopper dredge. A Section 401 Water Quality Certification has been requested from the North
Carolina Division of Water Quality. A Section 404(b)(1) (P.L. 95-217) Evaluation report for the
overflow of the hopper dredge has been prepared and included in the EA.
The work will not affect any species currently on the Federal list of threatened or
endangered species.
The proposed work has been evaluated pursuant to the provisions of the National
Historic Preservation Act of 1966, as amended. No known archaeological or historical
resources will be affected by the proposed action.
A list of Federal, State, and local agencies with whom this activity is being coordinated is
included with the FEIS No. 2, above.
The decision whether to perform this work will be based on an evaluation of the probable
impact, including cumulative impacts of the proposed activity on the public interest. That
decision will reflect the national concern for both protection and utilization of important
resources. The benefits which may reasonably be expected to accrue from the proposal must
be balanced against its reasonably foreseeable detriments. All factors which may be relevant
to the proposal will be considered, including the cumulative effects thereof; among those are
conservation, economics, aesthetics, general values, flood hazards, flood plain values, land
use, navigation, shoreline erosion and accretion, recreation, water supply and conservation,
water quality, energy needs, safety, food and fiber production, mineral needs, considerations
of property ownership, and in general, the needs and welfare of the people.
2
t
This notice is being distributed to all known interested persons concurrent with circulation
of the EA. For accuracy and completeness of record, all data in support of or in opposition to
the work should be submitted in writing within 30 days of the date of this notice setting forth
sufficient detail to support convictions. Any person who has an interest which may be affected
by the proposed action may request a public hearing. The request must be submitted in
writing to the District Engineer within 30 days of the date of this notice and must clearly set
forth the interest which may be affected and the manner in which the interest may be affected
by this activity. All correspondence should refer to the title, number, and date of this notice.
For further information or to receive a copy of the EA, contact Mr. Frank Yelverton, U.S. Army
Corps of Engineers, Post Office Box 1890, Wilmington, North Carolina 28402-1890, telephone
[phone].
U'62G
'1'V C. E. Shuford, Jr., P.
Acting Chief, Engineering
and Planning Division
Attachment
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