Attachment B_Battleship Special Investigatons Final Report_January 2017

US Army Corps
of Engineers
Wilmington District
SPECIAL INVESTIGATIONS REPORT
USS BATTLESHIP NORTH CAROLINA MEMORIAL
HYDROLOGY AND HYDRAULICS REVIEW AND POTENTIAL
STORMWATER IMPROVEMENTS
January 2017

Preface
The USS Battleship North Carolina Memorial is located on the west bank of the Cape Fear River
in New Hanover County, directly across from the Wilmington waterfront. It is owned by the
State of North Carolina and operated by state employees. The Park serves as a memorial to
North Carolinians who gave their lives in World War II, as well as an education center and top
tourist destination in the State of North Carolina.
In February of 2016, the Wilmington District visited the USS Battleship NC Memorial Park
following a request for assistance from Park officials concerning repetitive flooding events at
the Park. Although flooding events have occurred through the Parks history, there was concern
from Park officials that the frequency of these events had drastically increased in recent years.
These flooding events are a concern to the Park because of their economic, environmental and
operational impacts to the Park, as well as increased public safety concerns.
The Wilmington District discussed possible options for assistance from the USACE. These
options included a limited investigation through the Corps Special Investigations program, and a
Section 205 Flood Risk Management project through the Corps Continuing Authorities Program.
After consideration, the Battleship Memorial expressed interest in pursuing a limited
investigation under the Special Investigations program which would provide an analysis of
hydrology and hydraulics in the lower Cape Fear, as well as preliminary analysis on potential
storm water drainage improvements on the Park property.
This investigative report provides information from these analysis. The information is intended
to assist with potential planning decisions as well as provide some insight into the flooding
events in recent years.

Contents
1.0 Background............................................................................................................................................. 4
2.0 Field Review........................................................................................................................................... 6
3.0 Flooding Sources....................................................................................................................................
8
4.0 Water Level Analysis..............................................................................................................................
9
4.1 Tidal Analysis......................................................................................................................................
9
4.2 Sea Level Rise...................................................................................................................................
15
4.3 Cape Fear River Water Levels.........................................................................................................
16
4.4 Jordan Dam Releases.......................................................................................................................
17
4.5 Land Subsidence...............................................................................................................................
24
5.0 Potential Improvement Alternatives...................................................................................................
25
5.1 Alternative 1 - Stormwater Drainage Improvements.....................................................................
25
5.2 Alternative 2 - Increase Land Elevation...........................................................................................
25
5.3 Alternative 3 - Levee Protection......................................................................................................
26
6.0 Summary and Recommendations........................................................................................................
26
Appendix A - Battleship Aerial Plates (1-3)
Appendix B - Cost Information

1.0 Background
The USS Battleship North Carolina Memorial is moored adjacent to the Cape Fear River across
from Wilmington, NC. As a significant tourist destination and education center it receives over
one quarter -million visitors each year. Of concern is recurrent flooding of the Park property
and entrance road, which according to Park officials, has increased significantly in recent years.
This flooding comes primarily from the Cape Fear River during high tide events and has led to
significant impacts to the Park. The following are impacts as reported by Park officials:
Economic Impacts of Flooding:
➢ Lost revenue due to low or no visitation during flood events
➢ Lost revenue due to cancelled park and ship rentals
➢ Delays in deliveries of goods and services needed to operate the Memorial
➢ Delays to repair and renovations contracts
➢ Damage to facilities, ramps and maintenance vehicles
➢ Damage to landscaping — Trees and shrubs continue to die
➢ Potential loss of grants for park beautification due to risk of loss of shrubs and trees
➢ Damaged and disrupted utility services (electric, plumbing, etc.)
➢ Negative impressions among visitors & potential visitors regarding flooding will impact
numbers of families planning to visit
➢ Lost revenue from water taxi sales (impacts both Battleship and Downtown Wilmington)
Environmental Impacts of Flooding:
➢ Shoreline erosion
➢ Increased litter and debris in waterways
➢ Navigation hazards
➢ Erosion of visitor center support piles
➢ Sink holes in parking lot
➢ Possible sewage spills due to design of lift station
Operational Impacts:
➢ Increased liability for personal injury and property damage to visitors
➢ Increased likelihood of injuries to staff and damage to personal vehicles
➢ Delays in staff reporting to work
➢ Forced closures and delayed openings
➢ Strains on the infrastructure (Mooring lines, hull, ship structure)
Following a request form Park officials, US Army Corps of Engineers (USACE) staff visited the
Park in February 2016.The site was inspected by USACE staff both on 1 February 2016, and
during severe flood conditions on 8 February 2016. The level of flooding on 8 February
exceeded the normal flooding levels experienced at the park due to the addition of stormwater

runoff from a recent rainfall in addition to the high tide event. The photos in Figure 1 show
comparative views.
Figure 1. Comparative views from the deck of the USS NC Battleship Memorial without flooding
on 1 February 2016 during a lower tide, and during an extreme flooding event on 8 February
2016.
After discussion with Park officials about potential options for Corps assistance, it was
determined that a preliminary investigation would be conducted under the Special
Investigations Program. This investigation would provide an analysis of hydrology and
hydraulics in the lower Cape Fear, as well as provide a preliminary analysis on potential storm
water drainage improvements on the Park property. The following sections of the report
describe the analyses and findings.

2.0 Field Review
This section gives an overview of the field review conducted at the outset of the investigation.
During inspection at the time of flood conditions on 8 February2016, water from the Cape Fear
River was noted to flow west, laterally over the river bank and into the parking area (Figure 2).
Figure 2. Flooding from the Cape Fear River on 8 February 2016. View from Memorial to East.
River water was also flowing in the low lying marsh areas west of the parking areas and over
USS North Carolina Road (Figure 3).
Figure 3. Flooded entrance USS North Carolina Road. View from memorial to South.

A peak tide level of 4.24 ft NAVD88 was recorded at the NOAA National Ocean Service
downtown Wilmington gage (ID: 8658120). The Wilmington tide gage is located on the Cape
Fear River 0.6 miles downstream of the Battleship. Floodwater rose significantly faster than it
receded along the roadways and parking areas. The receding floodwater was hindered by an
undersized and damaged drainage system at the site.
A second site inspection and topographic survey of the drainage features was conducted on 2
June 2016 during non -flood conditions. The survey elevation data is provided in Plate 1 in
Appendix A. During the inspection it was noted that the drainage inlets and pipes at the
southeast corner of the parking lot along the north side of USS North Carolina Road were
damaged and undersized. Standing water was noted during low tide (figure 4). The 36" RCP at
the outlet into the Cape Fear River is undersized and was partially blocked with riprap and
debris (Figure 5).
Figure 4. Drainage South of Memorial Parking Area.

Figure 5. Drainage Outlet at Cape Fear River — undersized and partially blocked
The drainage ditch along the south side of USS North Carolina Road was noted to be overgrown
with vegetation and requiring clearing and re -grading to provide a constant slope. An
abandoned 30" RCP driveway culvert was located 140 ft east of the Battleship Road intersection
and should be removed. The 30" RCP under Battleship Road NE and the 30" outlet into the
Cape Fear River are both undersized. Inadequate drainage was also noted in the northwest
corner of the parking lot where elevations were under 2.0 ft NAVD88 and prone to frequent
flooding.
3.0 Flooding Sources
The major flooding events at the Battleship Memorial are caused by high water on the Cape
Fear River. When the Cape Fear River reaches elevation 2.70 ft NAVD88, water begins to
overtop its banks and flow into the vehicle parking areas and grassed park areas at the
Memorial. At elevation 3.30 ft NAVD88, river water begins to overtop NCDOT roadways USS
North Carolina Road and Battleship Road NE. River water can also enter the Memorial area
from the low -land marsh areas west of the Battleship. A color shaded elevation map of the area
surrounding the Memorial is provided in Plate 2 in Appendix A. Stormwater runoff can worsen

flood conditions at the Memorial but is secondary to high River water levels. Stormwater
drainage is hindered by the undersized and damaged pipe network (see section 2.0).
4.0 Water Level Analysis
The purpose of this analysis was to investigate the recent flooding events at the Battleship
Memorial and evaluate any increase in frequency of flooding. The analysis focused on flooding
events during the following months:
a. January 2015
b. September 2015
c. October 2015
d. November 2015
e. February 2016
4.1 Tidal Analysis
A summary of tide datums, elevations and ranges for the Wilmington tide gage is provided in
Table 1 on the following page. The mean high tide is 2.06 ft NAVD88 with a mean tide range of
4.28 ft. Flooding at the Battleship Memorial frequently occurs during periods of spring tides
that occur twice a month during the full and new moons. A perigean spring tide typically occurs
several times a year when the moon is closest to Earth and also occurs near a new or full moon
and results in the highest tides of the year. In 2015 perigean tides occurred in January,
September and October. September was a rare event in that the moon was the closest to Earth
on the same day as a full moon resulting in the highest astronomical tide in six years. The next
perigean tide will occur on May 25, 2017.

Table 1 - Summary of Tide Elevations, Wilmington, NC Station ID: 8658120
Datum
STND (ft)
MLLW (ft)
NAVD88 (ft)
Description
MHHW
7.13
4.68
2.31
Mean Higher -High Water
MHW
6.88
4.43
2.06
Mean High Water
MSL
4.89
2.44
0.07
Mean Sea Level
NAVD88
4.82
2.37
0.00
North American Vertical Datum of 1988
DTL
4.79
2.34
-0.03
Mean Diurnal Tide Level
MTL
4.74
2.29
-0.08
Mean Tide Level
MLW
2.61
0.16
-2.21
Mean Low Water
MLLW
2.45
0.00
-2.37
Mean Lower -Low Water
STND
0.00
-2.45
-4.82
Station Datum
MN
4.28
4.28
4.28
Mean Range of Tide
Maximum
10.60
8.15
5.78
Highest Observed Water Level
Max Date & Time
10/15/1954 12:30
Highest Observed Water Level Date/Time
Minimum
0.59
-1.86
-4.23
Lowest Observed Water Level
Min Date & Time
2/12/1981 10:30
Lowest Observed Water Level Date/Time
HAT
8.1
5.65
3.28
Highest Astronomical Tide
HAT Date & Time
4/8/1993 3:12
HAT Date and Time
LAT
1.78
-0.67
-3.04
Lowest Astronomical Tide
LAT Date & Time
1/21/1996 9:18
LAT Date and Time
The daily mean tide levels at the Wilmington and Wrightsville Beach gages are provided in
Figures 6 and 7 on the following page. From the figures, a significant spike in the tide can be
noted in the fall of 2015. The repeated flooding in the fall of 2015 occurred when higher than
normal astronomical tides coincided with persistent onshore winds and low pressure systems
including Hurricane Joaquin. The meteorological factors compounded the high tides resulting in
a long duration of elevated water levels along the mid -Atlantic coast of the US.

Average Daily Water Level Wilmington (NOS 8658120)
2.5
2
T 1.5
-2 '
1970 1974 1978 1982 1986 1990 1994 1998 2002 2006 2010 2014
Date (year) Data Interval Daily
Figure 6 — Average Daily Water Level at Wilmington Tide Gage 1970 to 2015
2.5
00 2
00
0
Q 1.5
1
v
J 0.5
m 0
awn -0.5
p -1.5
Average Daily Water Level Wrightsville Beach (NOS 8658163)
I
j
p �.
ice, .�71•�_..
. �! �•
i ��.••.�_
atn i .1, ��1
,� •4�,:,. :A� i. �'� �� �f;. ; +: i' s+•fit'! ' ; �'
�a• �,;sirs �y�' � . 'r�t; • • r ss1'+ '.., ���.::.�• ��:� ,
it} se ';1KCr: �:='S.� �� t» '7•••r Jf=�a•••`•' t.s `�!
1K '
.._
1
2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Date (year)
Figure 7 — Average Daily Water Level at Wrightsville Beach Tide Gage 2004 to 2015

Figures 8 through 12 compare the recorded water level at the Wilmington and Wrightsville
Beach tide gages during the five analysis months. The extreme levels approaching elevation 5.0
ft NAVD88 in September and October 2015 can be noted in Figures 9 and 10. It should also be
noted that the dates of the exceptionally high tides on the Cape Fear River and the high ocean
tides at Wrightsville Beach coincided.

PJ
-2
-3
-4
Water Level Wilmington and Wrightsville Beach
1
1
,
1
,
1;
;
s
�
1-Jan 5-Jan 9-Jan 13-Jan 17-Jan 21-Jan 25-Jan 29-Jan
January 2015
Wrightsville Beach Downtown Wilmington
Figure 8—Tide Gage Wilmington and Wrightsville Beach January 2015
5
4
3
00
00 2
0
Q
z 1
v 0
v
J
-1
2
-3
-4
Water Level Wilmington and Wrightsville Beach
i
1 ,
1 ;
1 ,
, ' 1
1}�
1-Sep 6-Sep 11-Sep 16-Sep 21-Sep 26-Sep
September 2015
Wrightsvilles Beach Downtown Wilmington
Figure 9 - Tide Gage Wilmington and Wrightsville Beach September 2015
1-Oct

5
4
3
2
W
M
Q 1
z
v O
v
-1
v
-2
-3
-4
Water Level Wilmington and Wrightsville Beach
1
1 �
'i
' � u
1-Oct 6-Oct 11-Oct 16-Oct 21-Oct 26-Oct
October 2015
-- Wrightsvilles Beach Downtown Wilmington
Figure 10 - Tide Gage Wilmington and Wrightsville Beach October 2015
Water Level Wilmington and Wrightsville Beach
5
4
3
-2
-3
-4
1-Nov 6-Nov 11-Nov 16-Nov 21-Nov 26-Nov
November 2015
-- Wrightsvilles Beach )owntown Wilmington
Figure 11 - Tide Gage Wilmington and Wrightsville Beach November 2015
31-Oct
1-Dec

Water Level Wilmington and Wrightsville Beach
5
4
3
'� 1; 1 1 I• 1
;
1 1 1 1 � 1 / 11 ,1 11 1, 1 1 11 1, • 1 � , 1 1 1
1 •1 ' 1, 1' i 1 11 ; I 1 1 „ 1 11 1 l{( 1 / 1 1 1 /
1.M
-4 1-
1-Feb
5-Feb 9-Feb 13-Feb 17-Feb 21-Feb 25-Feb
Febuary 2016
Wrightsville Beach Downtown Wilmington
Figure 12 - Water Level at Wrightsville Beach Tide Gage February 2016
29-Feb
4.2 Sea Level Rise
A graph of the sea level trend for the Wilmington tide gage is provided in Figure 13. The mean
sea level trend is increasing at 2.19 millimeters per year (0.086 inches per year). The mean
monthly sea level data used in the graph extends from 1935 to 2016. For comparison the sea
level trend for the Beaufort, NC tide gage (NOAA ID: 8656483) is 2.89 millimeters per year. In
Figure 6 an increasing trend in the mean tide level can also be noted starting in 2011, this could
be cyclical and not a part of the long-term trend.

0.60
0.45
0.30 -
0.15
N
L
0.00
v
- 0.15
-0.30 -
-0.45
-0.60
8658120 Wilmington, North Carolina 2.19 +- 0.35 mmlyr
— Linear Mean Sea Level Trend
At
_ — Lipper 95% Confidence Interval
- - - - - - - -
- - - - - - - - - - - - - - - - - - - - - - - - - -
— Lower 95% Confidence Interval
_ Monthly mean sea level with the
- average seasonal cycle removed
- - - - - - - -
- - - - - - - - - - - - - - - - --
tt-------
--------------------- 1i----------i---1---1-
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020
Figure 13 — Sea Level Trend Wilmington, NC (2.19 millimeters per year)
4.3 Cape Fear River Water Levels
The Cape Fear River Basin experienced above average flows during the fall of 2015 and winter
of 2016. The high river discharges were related to a strong El Nino Southern Oscillation that
brought above average precipitation to the southeastern United States. The monthly average
flows for the Cape Fear River at Lock & Dam #1 from 1981 to 2016 are provided in Table 2. Lock
and Dam #1 is located about 30 miles upstream of Wilmington with a watershed area of 5,255
square miles. The monthly average discharge for November and December 2015 and January
2016 were either the highest or second highest in 35 years for that particular month. October
2015 was the fifth highest and February 2016 the seventh highest for those months. The
monthly flows for all of the months were about twice the historic monthly average. During
November the observed water levels at the Wilmington tide gage averaged 0.7 feet higher than
predicted. The higher river flows contributed to the higher water levels seen at the Wilmington
tide gage.

Table 2 - Monthly Average Discharge Cape Fear River at Lock & Dam #1 near Kelly, NC
(USGS Gage 02105769)
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
1981
1,483
1,534
3,583
1982
11,180
11,120
11,000
4,102
5,024
15,070
3,202
3,020
1,003
1,625
1,681
6,073
1983
5,553
14,970
18,230
14,100
5,142
2,454
1,666
1,046
1,123
1,139
1,991
11,050
1984
12,840
12,910
16,790
16,980
4,737
4,985
8,317
7,883
2,762
1,598
1,442
1,935
1985
1 4,894
13,220
1 3,837
1,710
1 1,843
1,552
2,615
1 6,670
2,069
1,620
8,260
7,097
1986
2,265
3,025
5,460
1,667
1,272
1,147
1,046
3,135
1,313
1,133
1,484
2,756
1987
11,110
8,389
18,130
11,050
3,302
1,562
1,329
1,325
1,675
1,068
1,398
2,207
1988
7,167
5,447
3,629
3,851
2,067
1,556
1,716
1,531
2,856
2,276
3,687
1,938
1989
3,261
6,138
20,140
12,470
12,110
5,793
7,062
5,591
3,592
9,751
5,058
9,380
1990
8,801
12,750
7,022
9,537
7,315
3,832
1,305
1,651
985
5,942
3,209
5,051
1991
13,290
4,823
9,722
9,075
3,378
2,166
2,415
3,782
2,088
1,540
1,781
1,855
1992
5,261
3,532
6,934
5,713
2,254
6,638
2,576
3,272
1,312
1,798
6,850
7,396
1993
15,190
7,284
18,320
17,730
3,289
2,024
1,620
1,253
1,303
1,272
1,831
3,109
1994
6,199
8,650
11,780
7,377
1,826
2,336
2,391
3,650
3,609
2,704
1,869
2,863
1995
9,135
14,440
11,540
2,226
1,696
1 10,440
10,860
2,132
2,689
8,785
11,390
4,744
1996
9,050
9,836
8,435
5,684
4,744
2,416
1,897
3,288
22,580
9,151
4,440
8,286
1997
8,964
10,820
8,961
5,016
8,644
2,294
4,883
2,015
1,448
1,415
2,736
4,494
1998
17,180
27,780
23,830
13,560
5,827
1,900
1,039
1,375
1,417
1,023
1,118
1,783
1999
7,826
6,504
4,884
3,516
4,279
1,044
1,152
1,024
16,740
15,080
3,131
4,360
2000
8,007
13,020
7,303
6,013
2,376
1,396
2,343
2,449
4,629
2,127
1,703
1,967
2001
1,717
2,992
6,539
7,693
1,052
1 4,284
1,967
2,559
1,574
1,121
1,062
1,111
2002
4,743
3,445
3,016
2,924
968
874
802
776
1,270
5,551
8,448
10,120
2003
41866
9,224
20,890
21,650
8,042
10,920
9,036
13,400
6,756
2,690
3,083
6,098
2004
31101
7,183
5,798
3,677
3,512
2,128
1,793
5,029
10,110
3,775
3,132
5,537
2005
6,258
4,574
9,776
7,440
1,638
2,271
1,942
2,416
1,022
1,351
1,091
6,739
2006
4,407
2,959
2,012
2,466
3,443
6,230
3,641
1,645
3,598
1,783
12,870
9,243
2007
9,850
6,521
8,659
7,494
1,591
1,191
1,017
713
686
1,115
695
1,192
2008
2,128
2,571
6,289
7,261
3,227
1,018
1,345
2,342
9,368
1,916
2,177
6,173
2009
5,242
2,746
10,940
5,793
2,068
3,759
1,043
1,505
1,117
798
6,751
12,290
2010
10,150
17,990
6,716
4,139
2,763
2,488
1,205
1,233
1,154
3,408
1,216
1,320
2011
1,513
2,915
3,345
4,487
1,615
1,055
951
1,086
1,336
1,032
1,697
3,045
2012
1,723
2,162
5,401
2,003
2,699
1,264
1,346
1,891
2,374
1,418
1,216
2,216
2013
3,939
4,314
4,759
3,669
5,214
8,955
13,450
4,119
1,333
923
1,154
3,690
2014
11,100
9,281
11,220
8,004
6,165
1,322
1,218
2,110
2,150
1,314
1,658
3,483
2015
7,811
5,078
9,388
6,707
2,547
2,117
1,632
1,273
1,245
6,844
14,052
10,729
2016
15,732
13,002
5,651
3,807
5,708
2,855
3,181
21432
Monthly
Mean
7,470
8,332
9,610
7,160
3,811
3,524
3,000
2,875
3,538
3,073
3,626
4,998
4.4 Jordan Dam Releases
This section attempts to ascertain whether the Jordan Dam operations may be contributing to
flood events downstream in the area of the USS North Carolina Battleship Memorial. Jordan
Dam is located about 174 miles upstream of Wilmington, NC. The Haw River watershed at
Jordan Dam is 1,690 square miles and the Cape Fear River watershed at Wilmington is about
8,700 sq miles. The primary purpose of Jordan Dam is for flood control and to reduce
downstream flood levels. High inflows from Jordan Dam's watershed are held or detained

within the reservoir and then released after river conditions have peaked and flood stage
downstream of Jordan Dam has subsided.
During the fall of 2015 and winter of 2016, the watershed above Jordan Dam experienced high
rainfall amounts related to the El Nino event. Figures 14 through 18 show the daily averaged
inflow and outflow hydrographs for Jordan Dam from October 2015 to February 2016. The
outflow hydrograph shows the operation of the dam reducing the peak downstream flood
flows. During October the peak inflow was reduced by 70% before releasing downstream
helping to decrease downstream flood levels.
40,000
35,000
30,000
—"— 25,000
v
an
L
u 20,000
V)
15,000
10,000
5,000
7
October 2015 Jordan Dam Inflow and Outflow
— Oct 2015 Inflow
---•--- Oct 2015 Outflow
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31
Date
Figure 14 — Daily Average Inflow and Outflow at Jordan Dam, October 2015

November 2015 Jordan Dam Inflow and Outflow
40,000
35,000 Nov 2015 Inflow
30,000 •--- Nov 2015 Outflow
v
25,000 —
own
UU 20,000
15,000
10,000
5,000
0 V-4 Ilk . . . . . . . . . . . .
'.
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31
Date
Figure 15 — Daily Average Inflow and Outflow at Jordan Dam, November 2015
December 2015 Jordan Dam Inflow and Outflow
40,000
35,000 Dec 2015 Inflow
Dec 2015 Outflow
30,000
v
25,000
tin
20,000
15,000
10,000
5,000
0
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31
Date
Figure 16 — Daily Average Inflow and Outflow at Jordan Dam, December 2015

January 2016 Jordan Dam Inflow and Outflow
40,000
35,000 Jan 2016 Inflow
30,000 --- Jan 2016 Outflow
v
25,000
own
u 20,000
0
15,000
10,000 -
5,000 i •,,. •
0
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31
Date
Figure 17 Daily Average Inflow and Outflow at Jordan Dam, January 2016
Febuary 2016 Jordan Dam Inflow and Outflow
40,000
35,000 Feb 2016 Inflow
30,000 •--- Feb 2016 Outflow
v
25,000
r�
20,000
U
0
15,000
i
10,000
5,000
0
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31
Date
Figure 18 — Daily Average Inflow and Outflow at Jordan Dam, February 2016

Figures 19 through 22 are additional plots of the observed Wilmington tide gage with
precipitation at Jordan, Lock & Dam #3 and Wilmington and observed flow along the Cape Fear
River. The dates of full moon (FM) and new moon (NM) spring tides are noted, as is the peak
stage (green down arrow). The delay of the peak flow wave as it moves downstream from
Jordan, to Lillington, to Lock & Dam #3, to Lock & Dam #1 and finally at the Wilmington tide
gage can be noted. The plots also compare the magnitude of flow released from Jordan Dam to
the flow at Lock & Dam # 3. Overall, the rainfall and flow in the upper Cape Fear basin nearest
the dam are relatively smaller than what occurred in the lower Cape Fear, nearest Wilmington.
Additionally, the time delay for the upper basin flows to reach the lower basin occurred after
peak flows in the river system. The conclusion of this analysis is that Jordan Dam operations
are not a contributing factor to high water levels in the lower Cape Fear River near Wilmington.
65
6.0
r
m 5.5
m
50
4.5
40
40,000
35,000
30.000
25.000
0 20.000
L�
15,000
10,000
5,000
0
5
4
3
2
d
1
0
27 4 11 18
Sep2015 Oct2015
— WLON 14PLUS NOAA STAGE •••••• JORDAN D OUTFLOW FLOW --- MONCURE DCP FLOW LCK1 DCP FLOW
—•—• LILLINGTON DCP FLOW — LK&DAM 3 DCP FLOW ...... JORDN OBSERVED PRECIP-INC — WILM CRONOS PRECIP
LK&DM 3 DCP FRECIP-INC
Figure 19 — Observed Wilmington Tide, Cape Fear River Discharge and Precipitation Sep -Oct
2015

6.0
5.5
m
a 50
45
40
40.000
35,000
30,000
25,000
0 20.000
LL
15.000
10.000
5,000
0
2.0
15
10
m
a
0.5
0.0
November 24, 2015
n
FM
1.5 dy
VII
[-1 dy .` �-- 2 _d -
i
H
•
— WLON 14PLUS NOAA STAGE
—•—• LILLINGTON DCP FLOW
— LK&DM 3 DCP PRECIP-INC
8
•••••• JORDAN D OUTFLOW FLOW
— LK&DAM 3 DCP FLOW
15
Nov2015
--- MONCURE DCP FLOW
...... JORDN OBSERVED PRECIP-INC
22
LCK1 DCP FLOW
— WILM CRONOS PRECIP
Figure 20 — Observed Wilmington Tide, Cape Fear River Discharge and Precipitation Nov 2015.

6.5
60
1✓ 5.5
m
m
5.0
45
40
80,000
70.000
60.000
50,000
�F 40.000
30,000
20.000
10.000
0
2.0
0.0
January S, 2016
V
N•I� I
20 27 3 10
Dec2015 Jan2016
— WLON 14PLUS NOAA STAGE •••••• JORDAN D OUTFLOW FLOW --- MONCURE DCP FLOW - - LCK1 DCP FLOW
—•— LILLINGTON DCP FLOW — LK&DAM 3 DCP FLOW •••••• JORDN OBSERVED PRECIP-INC — WILM CRONOS PRECIP
— LK&DM 3 DCP PRECIP-INC
Figure 21 — Observed Wilmington Tide, Cape Fear River Discharge and Precipitation Jan 2016.

6`
6C
4`
4C
35,00C
30,00C
25,00C
20,00C
0
15,00C
10,00C
5.000
C
3`
3C
2`
2C
a�
1:
a 1C
0`
0C
February 8, 2016 n NM
1W
�2.Sdy�
f- ti
Jan2016 _ Feb2016
— WLON 14PLUS NOAA STAGE •••••• JORDAN D OUTFLOW FLOW --- MONCURE DCP FLOW ---- LCK1 DCP FLOW
-•-• LILLINGTON DCP FLOW - LK&DAM 3 DCP FLOW ...... JORDN OBSERVED PRECIP-INC WILM CRONOS PRECIP
- LK&DM 3 DCP FRECIP-INC
Figure 22 — Observed Wilmington Tide, Cape Fear River Discharge and Precipitation Feb 2015.
4.5 Land Subsidence
Much of the developed land adjacent to the Cape Fear River in Wilmington is built on material
dredged from the Cape Fear River. The timing, extent and quality of the material placed in the
area of the Battleship Memorial is unknown. Over time dredge material will compact and the
weight of the material can also compress the underlying foundation material. This results in
subsidence or a lowering in the land surface elevation. The amount of subsidence at the
Battleship Memorial is unknown. The benchmarks located in the grassed area along the River
have been disturbed and the original elevations were not documented to quantify the amount
of subsidence. Land subsidence may be a factor in the increased flood frequency and additional
research is required to quantify. If usable landmarks are discovered in the future, further
analysis can be conducted to determine the potential role this may play, if any, in high tide
flood events.

5.0 Potential Improvement Alternatives
Three basic alternatives were preliminarily investigated in this effort. Each have the potential
to help manage the flooding issues at the Battleship Memorial, although alternative 3 was
deemed impractical during this preliminary analysis.
5.1 Alternative 1- Stormwater Drainage Improvements
The first alternative includes upgrading the stormwater drainage system for the roadways and
parking areas. The existing drainage system is damaged and undersized and does not allow for
the complete drainage of the area between tide cycles. This alternative does not prevent or
reduce the peak flood levels caused by high water on the Cape Fear River but it will significantly
speed-up the time to drain the floodwater. Improved drainage will allow for quicker return to
normal tour activities and reduced flood damage. A concept plan for improvements is provided
in Plate 3 in Appendix A. The most important improvement is the removal of the damaged
drainage pipes along the north side of USS North Carolina Road and enlarging the outlet pipe
discharging into the River. The pipes should be replaced with a series of open grassed swales
and roadway culverts under the three parking lot entrances. Open grassed swales are
recommended over piped sections to avoid grated drop inlets that frequently become clogged
and restrict flow. The proposed drainage improvements are a concept design and will require
additional surveying and engineering design and coordination with NCDOT. A rough order of
magnitude cost estimate for this alternative is approximately $290,000. Cost details are located
in Appendix B.
5.2 Alternative 2 - Increase Land Elevation
The second alternative is to raise the roadways and parking areas above the more frequent
flood elevations using fill material. Raising the elevations to 5.0 ft NAVD88 would be 0.5 ft
above the most recent floods experienced. The total amount of fill material required for the
roads and parking area is estimated to be at least 26,300 cubic yards (CY). This alternative
would require new pavement and landscaping. USS North Carolina Road and Battleship Road
NE are both NCDOT maintained roads and would require approval and coordination with the
NCDOT. Funding and/or cost -sharing would have to be determined. This alternative would also
require the drainage improvements described in Section 5.1. A rough order of magnitude cost
estimate for this alternative (which includes Alternative 1 measures) is approximately
$2,650,000. Cost details are located in Appendix B

5.3 Alternative 3 - Levee Protection
The third alternative considered includes constructing a system of levees or dikes to contain the
parking area and prevent flooding from the Cape Fear River. The levee system would require
pumps to remove interior stormwater. The levee system would be required to surround the
parking area and would not address the issue of flooding along NCDOT roadways. This
alternative is not practical because of the need to rely on pumps to remove interior drainage,
therefore no cost analysis was done. However, it is assumed that costs for this alternative
would be substantial, to include long-term maintenance costs of the levee system and
maintenance of the interior drainage pumps.
6.0 Summary and Recommendations
The frequent flooding during the fall of 2015 and winter of 2016 at the USS North Carolina
Battleship Memorial was related to several factors. Flooding is caused by the Cape Fear River
overtopping its banks during high tide and inundating the roadways and parking areas. Recent
flooding occurred when a set of exceptionally high perigean tides coincided with above average
flows on the Cape Fear River and with persistent offshore weather patterns that increased
water levels along the mid -Atlantic coast. An astronomical perigean tide occurs when the moon
is closest to the Earth and overlaps a typical bi-monthly spring tide. The Cape Fear River at Lock
& Dam #1 recorded either the highest or second highest monthly average flow (for that month)
in 35 years during November and December 2015 and January 2016. Offshore weather systems
including Hurricane Joaquin caused the ocean tide gages at Wrightsville Beach, Beaufort, NC
and Myrtle Beach to record water levels several feet above the predicted tide during the fall of
2015. These three factors contributed to produce the unusually high and numerous flooding
events at the Memorial. Heavy rainfall in the area during a strong El Nino year compounded the
flooding.
The increase in flood frequency over the past decade as noted by Memorial Directors is likely
related to the increase in the sea level as measured at the Wilmington tide gage. Subsidence of
the land surface elevation over the past decades may also be a factor, as dredged fill material
was likely used to build the roadways and parking areas. However, this could not be confirmed
during this investigation. Analysis indicates that operations at Jordan Dam are not a factor.
Raising the roadways and parking areas with fill material may be the most appropriate long-
term solution to flooding at the Battleship Memorial, and for providing unimpeded emergency
and visitor access. A phased approach with improving the stormwater drainage system first
could also be one approach. The existing drainage system is damaged and undersized which
prevents adequate drainage of floodwater from the roadways and parking areas. A site visit

during flood conditions caused by high water on the Cape Fear River revealed standing water
unable to drain quickly as the tide receded on the River. Improving the drainage system will not
prevent or reduce peak flood elevations caused by high water on the Cape Fear, but it will allow
flood water to drain significantly faster and allow operations to return to normal sooner. The
proposed drainage improvements would be compatible with and would be required for any
future raising of the roadways and parking area.

APPENDIX A
Battleship Aerial Plates
1-3

IF 9'
{ co
r New 24" RCP with 0 �i-
` �s�tor Center Flap -Gate Outlet
"alp.
4 USS Battleship North Carolina Memorial
Concept Design
Flood Drainage Improvements
• New 24" RCP with AW
Flap -Gate Outlet 0.0
Ad
* •� I J � i
y r
i
Legend
oil
Drainage Ditch
1 -
+� New Culvert (RCP) y
T 6
� I �
mF
- - - New Headwall
at Outlet r j
Improved Grass Swale
r Upgrade Culvert
' j' * r Remove Old RCPs 3 - 36" RCP
- w . New Grass Swale
Upgrade Culvert
=
i • Remove Old RCPs 2 - 36" RCP _
Upgrade Culvert r -
New Culvert p1g- 36" RCP New Grass Swale = —
'- 1-24"RCP
r� Upgrade Culvert
3 - 36" RCP
Clear and Re -Grade s .
Upgrade Culvert Drainage Ditch
Improved Grass Swale (JSS North Carolina Road 2 - 36" RCP New - Headwall E -
- = * _
_ _ i • _ at Outlet -
Clearand Re -Grade _ t , - �. � Remove 30" RCP
_ Drainage Ditch + ♦* Culvert Plate 3
dI
yj M USS Battleship or Carolina
' + � 0 100 200 Concept Design USACE -Wilmington � � I �
Concept Design Not for Consfirucfiion Feet Drainage Improvements Map Date: 10/6/2016
E-sri, HERE, DeLorme, M'apm India, ©OpenStreetMap contributors

APPENDIX B
Cost Information

Print Date Thu 10 November 2016
Eff. Date 11/4/2016
U.S. Army Corps of Engineers Time 16:55:52
Project: BATTLESHIP ROM
ROM BATTLESHIP Title Page
BATTLESHIP ROM
Estimated by Susan Brokenshire
Designed by
Prepared by
Preparation Date 11/4/2016
Effective Date of Pricing 11/4/2016
Estimated Construction Time 60 Days
This report is not copyrighted, but the information contained herein is For Official Use Only.
Labor ID: NC- 2015 EQ ID: EP14R03 Currency in US dollars TRACES MII Version 4.3

Print Date Thu 10 November 2016 U.S. Army Corps of Engineers
Eff. Date 111412016 Project: BATTLESHIP ROM
ROM BATTLESHIP
BATTLESHIP ROM
BATTLESHIP ROM
Repair RCP, asphalt and swales
Public storm utility drainage piping, reinforced concrete pipe (RCP), 24" diameter, 8' lengths, class 3, excludes excavation or backfill, gaskets
Public storm utility drainage piping, reinforced concrete pipe (RCP), 36" diameter, 8' lengths, class 3, excludes excavation or backfill, gaskets
Selective demolition, water & sewer piping & fittings, concrete pipe end pieces, 24"-36", diameter, excludes excavation
Dewatering, excavate drainage trench, with backhoe
Concrete culvert, headwall concrete, precast, 30 degree skewed wingwall, 24" diameter pipe
Concrete culvert, headwall concrete, precast, 30 degree skewed wingwall, 36" diameter pipe
Rip -rap, random pieces, dumped from truck, 10 - 200 pound pieces
Selective demolition, saw cutting, asphalt, up to 3" deep
Asphalt paving, plant mixed asphaltic base courses for roadways and large paved areas, bituminous concrete, 4" thick
Selective clearing, wet clearing, heavy brush and trees, excludes removal offsite
Excavate and load, bank measure, medium material, 2-3/4 C.Y. bucket, track loader
Hauling, excavated or borrow material, loose cubic yards, 6 mile round trip @ 40 MPH (2.1 cycles/hour), 16.5 C.Y. dump trailer, highway haulers,
excludes loading
MARINE EQUIPMENT, BOATS & LAUNCHES, 19' ROUSTABOUT, TRI HULL, NO CABIN, CAP 2,600 LBS, OUTBOARD, 19.4' X 8.5' X 0.8'
Flap gates, hydraulic structures, aluminum, 24" diameter
Mob Demob
Mobilization or demobilization, delivery charge for equipment, hauled on 40-ton capacity towed trailer
Toilet, portable, chemical, rent per month
Mobilization or demobilization, delivery charge for small equipment, placed in rear of, or towed by pickup truck
PED costs
PED Costs
S&A costs
S&A Costs
OPTION Raise parlking lot and road
Compaction, 3 passes, 24" wide, 12" lifts, walk behind, vibrating roller
Asphaltic concrete paving, parking lots & driveways, 6" stone base, 2" binder course, 2" topping,
Seeding, mechanical seeding hydro or air seeding for large areas, includes lime, fertilizer and seed
Time 16:55:52
BATTLESHIP ROM Page 1
Quantity UOM ProiectCost
2,649,619.46
1.00 EA 2,649,619.46
1.00 EA 291,028.92
310.00
LF
14,814.69
610.00
LF
65,895.27
670.00
LF
3,179.92
669.00
CY
2,518.08
18.00
EA
67,157.34
2.00
EA
8,230.64
300.00
LCY
18,398.89
980.00
LF
1,114.44
933.00
SY
24,941.94
2.00
ACR
1,491.47
1,091.00
BCY
1,208.66
1,091.00
LCY
3,064.44
4.00 WK 18,574.69
4.00
EA
27,715.99
6.00
EA
3,689.07
6.00
EA
3,293.66
2.00
MO
319.51
2.00
EA
75.90
1.00
EA
17,490.00
1.00
EA
17,490.00
1.00
EA
11,543.40
1.00
EA
11,543.40
1.00
EA
2,358,590.54
26,300.00
ECY
19,805.36
20,854.00
SY
784,008.74
3.00
ACR
13,451.26
Labor ID: NC- 2015 EQ ID: EP14R03 Currency in US dollars TRACES MII Version 4.3

Print Date Thu 10 November 2016
Eff. Date 11/4/2016
U.S. Army Corps of Engineers
Project: BATTLESHIP ROM
ROM BATTLESHIP
Cycle hauling(wait, load, travel, unload or dump & return) time per cycle, excavated or borrow, loose cubic yards, 30 min load/wait/unload, 18 C.Y. 8
wheel truck, cycle 20 miles, 45 MPH, excludes loading equipment
Structural concrete, in place, spread footing (3000 psi), under 1 C.Y., includes forms(4 uses), Grade 60 rebar, concrete (Portland cement Type 1),
placing and finishing
In -place hot reused asphalt paving, recycle asphalt pavement at site, 4" deep, remove, rejuvenate and spread
Fill, dumped material, spread, by dozer, excludes compaction
Pavement markings, parking stall, paint, white, 4" wide
Borrow, common earth, 1-1/2 C.Y. bucket, loading and/or spreading, shovel
Light poles, anchor base, aluminum, 16' high, excl concrete bases
Foundations for utility pole, to 35' h, includes excavation & concrete
Mob Demob
Mobilization or demobilization, delivery charge for equipment, hauled on 40-ton capacity towed trailer ONE ADDITIONAL DOZER
Toilet, portable, chemical, rent per month
Mobilization or demobilization, delivery charge for small equipment, placed in rear of, or towed by pickup truck
FED costs
PED Costs
S&A costs
S&A Costs
Time 16:55:52
BATTLESHIP ROM Page 2
Quantity UOM ProiectCost
26,300.00 LCY 165,237.23
27.00 CY 7,471.89
20,854.00
BY
226,874.48
26,300.00
LCY
34,710.20
384.00
STL
4,352.43
26,300.00
BCY
768,137.99
27.00
EA
54,485.87
27.00
EA
42,412.29
6.00
EA
1,493.30
2.00
EA
1,097.89
2.00
MO
319.51
2.00
EA
75.90
1.00
EA
136,735.50
1.00
EA
136,735.50
1.00
EA
99,414.00
1.00
EA
99,414.00
Labor ID: NC- 2015 EQ ID: EP14R03 Currency in US dollars TRACES Mill Version 4.3

Print Date Thu 10 November 2015
U.S. Army Corps of Engineers
Time 16:55:52
Eff. Date 11/4/2016
Project: BATTLESHIP ROM
ROM BATTLESHIP
Table of Contents
Description
Page
BATTLESHIPROM.........................................................................................................................................................................................................................................................................................................................................................................................................................
1
BATTLESHIP ROM .......................................................................................................................................................................................................................................................................................................................................................................................................................
1
Repair RCP, asphalt and swales ....................................................................................................................................................................................................................................................................................................................................................................................
1
Mob Demob
PEDcosts..........................................................................................................................................................................................................................
........................................................................................................................................................................
1
S&A costs .......................................................................................................................................................................................................................................................................................................................................................................................................................................
1
OPTION Raise parlking lot and road
1
Mob Demob ...............................................................................................................................................................................................................................................................
2
PED costs ...........-..........................................................................................................................................................................................................................................................................................................................................................................
.......................................................................................................................................
2
S&A costs
2
Labor ID: NC- 2015 ED ID: EP14R03 Currency in US dollars TRACES MII Version 4.3