19910121 Ver 1_COMPLETE FILE_19910202

IN REPLY REFER TO
DEPARTMENT F HE ARMY
WILMINGTON DISTRICT, CO PS OF EN
P.O. BOX 1890
WILMINGTON, NORTH CAROLINA 28402=I
Planning Division
June 17, 1994
Mr. Roger Schecter, Director
Division of Coastal Management
North Carolina Department of Environment,
Health, and Natural Resources
Post Office Box 27687
Raleigh, North Carolina 27611-7687
Dear Mr. Schecter:
GINEERS l?
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89Q` /
JUU w7 1
DIV. OF ENVIRONI1MAL MQ1IR
DIRECTORS OFFICE
Enclosed are the results of our evaluation of the expansion of the
dredged material disposal islands adjacent to the Manteo-Oregon Inlet
Channel and Old House Channel, Manteo (Shallowbag) Bay project, Dare
County, North Carolina (figure 1).
At a State-Corps dredging coordination meeting held in Morehead
City on January 4, 1991, the Wilmington District, for mitigation
purposes, agreed to determine the net acreage that each island has
expanded since 1977. Mitigation would be in the form of oyster reef
construction. As agreed, implementation of the mitigation plan for
the disposal islands was delayed in order to obtain information on
construction techniques and monitoring needs from the implementation
of a separate oyster reef mitigation plan for the expansion of the
Island H upland diked disposal island near Wanchese. Under the
Island H mitigation plan, 13 acres of oyster reefs were constructed
in 1993 in the vicinity of Wanchese.
If you have any questions regarding the evaluation or the decision
to proceed with the mitigation as a result of the expansion of the
island, please contact Mr. Daniel Small, Environmental Resources
Branch, at [phone].
Sincerely,
Lawrence W. Saunders
Chief, Planning Division
Enclosures
JUN 28 19;'4 J
VIAT P% OUf?,I..rr
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Copies Furnished (with enclosures):
f Dr. George Everett, Director
Division of Environmental Management
North Carolina Department of Environment,
Health, and Natural Resources
521 North Salisbury Street
Post Office Box 27687
Raleigh, North Carolina 27687-7687
Dr. William T. Hogarth, Director
Division of Marine Fisheries
North Carolina Department of Environment,
Health, and Natural Resources
Post Office Box 769
Morehead City, North Carolina 28557-0769
Mr. Dennis Stewart
North Carolina Wildlife
Resources Commission
Route 2, Box 310
Winterville, North Carolina 28590
Regional Administrator
U.S. Environmental Protection Agency
Region IV
345 Courtland Street, NE.
Atlanta, Georgia 30365-2401
Ms. L. K. Gantt, Supervisor
Fish and Wildlife Enhancement
U.S. Fish and Wildlife Service
Post Office Box 33726
Raleigh, North Carolina 27636-3726
Mr. Larry Hardy
Habitat Conservation Division
National Marine Fisheries Service
Pivers Island
Beaufort, North Carolina 28516
4.,
SUMMARY REPORT
Expansion of Dredged Material Disposal Islands
Manteo/Oregon Inlet-Old House Channels
Manteo (Shallowbag Bay) Project, Dare County, North Carolina
Background. Maintenance dredging of the Manteo-Oregon Inlet Channel and Old
House Channel involves removal of approximately 270,000 cubic yards of
material annually with disposal of the dredged material on the disposal
islands along the navigation channels (Figure 1). The control-of-effluent
method of disposal of dredged material is used to place material on all of
the disposal islands except for Island H, where diked upland disposal of
dredged material is used. The effluent from the discharge of dredged
material on these islands is directed back towards the channel, except for
islands N, 11, and L where the effluent is directed to the nonchannel side.
Since 1977, islands B, C, D, F, G, H, L, M, and N have been used on a
continuous basis for the disposal of dredged material from maintenance
dredging operation in the adjacent channels. Islands A, E, I, and J have
not been used since 1977. Island "K" has disappeared since 1977. Islands
"M" and "N" have merged since 1977. Sandshoal Island, which was created in
1986 as a result of disposal of dredged material on a shoal located adjacent
to the Oregon Inlet Channel was approved as a dredged material disposal
island in 1989. Wells Island, a sandbag island along Old House Channel, was
approved for dredged material disposal in 1980 and was constructed in 1988.
A 12-acre sandbag disposal island, located to the north of Wells Island, was
approved for construction in 1993 (Figure 1). Mitigation for the
construction of this island is also included in the total acreage that will
be mitigated.
Mitigation. Mitigation for estaurine bottom losses associated with new work
as well as operation and maintenance work for the Manteo (Shallowbag) Bay
project involves out-of-kind mitigation through the construction of oyster
reefs (combination of seed oyster relaying and cultch planting) in the
general project area. The mitigation plan for the Manteo (Shallowbag) Bay
project is described in the U.S. Fish and Wildlife Service mitigation plan
dated August 21, 1980. The mitigation plan calls for the construction of
0.66 acres of oyster reefs for each acre of estuarine bottom raised above
mean high water.
Method and Results. At a State-Corps dredging coordination meeting held in
Morehead City on January 4, 1990, the Corps, for the purpose of mitigation
requirements, agreed to determine the net acreage of expansion of the
disposal islands. The acreages included in the 1980 FSFEIS (Table 1) which
were determined by planimetering aerial photographs taken in November 1977,
were used for the baseline. Recent (April 1990) aerial photography of the
islands were used to planimeter their present size.
The acreage obtained from the November 1977 photographs (Figure 2) were
subtracted from the acreage obtained from the April 1990 photographs (Figure
3). The net acreage for each island is shown on attachment 2.
Enclosure 1
r
In addition to the existing disposal islands, a new 12-acre sandbag
disposal island, located to the north of Wells Island, was approved for
construction in 1993. The net total (both +/-) acreage of estaurine bottom
covered for all of the islands used on a regular basis since 1977 is 102.4
acres. The total number of acres of oyster reefs that will be constructed
.to compensate for estuarine bottom raised above mean high water as a result
of the disposal of dredged material will be 68 acres (102.4 acres x 0.66
acres).
Construction and Monitoring. The Corps of Engineers, Wilmington District,
and the North Carolina Division of Marine Fisheries (NCDMF) will use the
existing Memorandum of Agreement (MOA), signed by the two agencies in
November 1991 to construct the oyster reefs.
The NCDMF, Shellfish Rehabilitation Branch, will be responsible for
construction of the oyster reefs through a combination of seed oyster relay
and cultch planting. Construction will be located in areas identified by
local fishermen (in consultation with the NCDMF and the U.S. Fish and
Wildlife Service) as productive oyster areas in eastern Dare County.
Samples will be taken at each site twice each year to determine the
suitability of the sites and the rehabilitation methods used. For relayed
stocks, data on average size at planting, number of oysters per bushel, and
growth will be taken. For cultch planting areas, data will be recorded on
oysters per piece of cultch and growth and average size of oysters on the
site. A report will be submitted to the Wilmington District upon completion
of construction. A report on monitoring activities will be provided
annually to the Corps of Engineers.
The life of the project is 50 years. The Corps of Engineers will pay
for the initial construction (1 year) and the first 4 years of monitoring.
The NCDMF will assume operation and maintenance of the reefs for the
remaining 45 years of the project life.
2
figure

Ile

ISLAND 'H'
12.2 AC.

ISLAND '0'
\ 11.5 AC.

,
\
12LAND 'F'
20.6 AC.

ISLAND 'D'
22.5 AC.

ISLAND 'C'
41.1 AC. ISLAND 'E'
?14.3 AG.

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ISLAND 1' '?`-•__?•
5 AC.

ISLAND 'M' /
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20.2 A0.
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ISLAND 'N'
12.2 A[.
MA EO (SHALLOWBAG) BAY
NORTH CAROLINA
DREDGED MATERIAL
DISPOSAL ISLANDS - 1977
SCALE 1'2000'
NOTEI ISLAND LOCATIONS ARE APPROXIMATE.
AREAS DIGITIZED FROM AERIAL PHOTOGRAPHS.
Figure 2
ISLAND 'H'
17.1 AC.
\3 2.
ISLANO '0'
\ J1. 11.2 A.
ISLAND 'i'
11.1 AC.
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17.7 AC.
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MANEO (SHALLOWBAG) BAY
NORTH CAROLINA
DREDGED MATERIAL
DISPOSAL ISLANDS - 1990
SCALE 1'4000'
HOTEI ISLAND LOCATICNS ARE APPROX14ATE.
L AREAS DIGITIZED FROM AERIAL PHOTOCRAPHS.
SANDSXOAL ISLAND
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Disposal
Island
"B1(
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MANTEO (SHALLOWBAG) BAY PROJECT
Manteo/Oregon lnlet-Old House Channel Disposal Islands
"M & N"
"Wells Island"
"Sandshoal"
Sandbag Island
NOTE:
1977 1990 1977-1990
Acrea ge Acreage Change (+/-)
23.0 acres 11.5 acres -11.5 acres
60.3 acres 65.0 acres +04.7 acres
31.1 acres 49.8 acres +18.7 acres
43.9 acres 31.0 acres -12.9 acres
16.3 acres 14.6 acres -01.7 acres
18.1 acres 18.0 acres -00.1 acres
19.9 acres 57.4 acres +37.5 acres
41.4 acres 58.5 acres +17.1 acres
00.0 acres 19.9 acres +19.9 acres
00.0 acres 19.0 acres +19.0 acres
00.0 acres 00.0 acres +12.0 acres*
Net Total - +102.4 acres
1. Islands " A," "E," "1," and "J" have not been used since 1977.
2. Island "K" has disappeared since 1977.
3. Islands "M" and "N" have merged since 1977.
4. Islands were planimetered using November 1977 aerial photography
and April 1990 aerial photography.
5. *The 12-acre sandbag disposal island, located to the north of Wells
Island, was approved for construction in 1993. The island will be
constructed in 1994.
Enclosure 2