20150955 Ver 1_Memo of Findings_20131205

ZR 4709 COLLEGE ACRES DRIVE
€ SUITE 2
I N C O R P O R A T E D WILMINGTON, NORTH CAROLINA 28403 -1725
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FAX [phone]
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MEMORANDUM OF FINDINGS
TO: Kathy Herring, North Carolina Department of Transportation - Natural Environment Unit
FROM: Michael Neal, CZR Incorporated
RE: Submerged Aquatic Vegetation (SAV) Surveys for Topsail Island Bridge Replacement
Project (B- 4929), Pender County, INC
DATE: 05 December 2013
Introduction
The North Carolina Department of Transportation ( NCDOT) has proposed to replace the existing,
structurally deficient swing -span bridge currently providing access to Topsail Island along NC 50/210 in
Surf City, Pender County, NC. In accordance with the National Environmental Policy Act (NEPA), NCDOT
has been conducting studies for this replacement project, State Transportation Improvement Program
(STIP) project number B -4929, to determine potential impacts within the project study area. After
federal, state, and local environmental agency review, Alternative 17 bridge alignment (Alt 17
alignment) was selected as the preferred alternative for the bridge replacement project (Federal
Highway Administration and North Carolina Department of Transportation 2011).
Purpose and Need
The purpose of this study was to document the presence and extent of submerged aquatic vegetation
(SAV) to provide baseline information (SAV species present and estimated percent cover) for evaluation
of Alt 17 project impacts to SAV and potential mitigation associated with the SAV resources. The need
for SAV surveys was based on a request from the North Carolina Division of Marine Fisheries (NCDMF).
A site visit by Jessi O'Neal of NCDMF resulted in confirmation of SAV habitat area and the location to be
surveyed monthly during the growing season (M.K. Herring & K.M. Kendig- NCDOT, personal
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communication, 28 and 30 October 2013). This memorandum presents the findings of four SAV surveys
during 2013 and documents the survey methodology.
Tasks Completed by CZR
• Participated in survey area orientation and reconnaissance with NCDOT staff on 14 May 2013 to
discuss and develop an appropriate sampling methodology. A summary of the reconnaissance
and field notes from the meeting, discussion, and informal survey was provided to NCDOT.
• Developed a NCDOT- approved sampling methodology and data form specifically for the study
area.
• Provided three staff, GPS and water quality sampling equipment, survey quadrat markers,
underwater view buckets, and a shallow -draft boat to transport personnel between the boat
launch area in Soundside Park and the survey area.
• Conducted four (4) SAV surveys with NCDOT staff on 04 June, 16 July, 09 August, and 12
September 2013 (during the SAV growing season).
Methods
The 0.21 -acre survey area (50 feet by 180 feet) situated within the Alt 17 alignment west of the Atlantic
Intracoastal Waterway (Figure 1). In an effort to aid data collection and keep observers oriented while
completing their visual estimates of percent cover, the survey area was subdivided into eight survey
quadrats (25 feet by 45 feet). Estimates of percent cover were aided by a crown density scale used to
determine the density of SAV beds (modified from Paine 1981) (Figure 2). A Trimble GeoExplorer 2005
series handheld GPS unit was used both to ensure accuracy in establishing the survey area within the Alt
17 alignment and to record the four corners of the 50' x 180' survey area during the initial survey to
ensure subsequent surveys were performed in the same area.
Tools and materials used to set up the survey plot and sampling quadrats:
• (1) Trimble GeoExplorer 2005 series handheld GPS unit
• (1) 200 foot measuring tape
• (15) 5 -foot PVC pole (0.75 -inch diameter)
Prior to performing the survey each month, the survey area boundaries and quadrats were identified
and re- staked using the PVC markers. The four corners of the 50 X 180 foot survey area were located
using the GPS unit (Table 1). Next, the eight quadrats were established within the survey area using line
of sight and the measuring tape. Water quality parameters (temperature, dissolved oxygen
concentration, conductivity, salinity, and pH) were recorded once in the northeastern corner of quadrat
#8 using the YSI Professional Plus instrument. Secchi depth was also measured prior to beginning the
survey.
Topsail Island Bridge 2 December 2013
Replacement SAV Survey CZR Incorporated

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SAV Survey Area and Vicinity
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SCALE: AS SHOWN
APPROVED BY:
DRAWN BY: BFG
Alt 17 Alignment
DATE: 11/8/13
FILE: Topsail_Isl —d Bndq,
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Topsail Island Bridge 3 December 2013
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SCALE: NOT TO SCALE APPROVED BY: DRAWN BY: BFG /TLJ
DATE: 11/08/13 FILE: CrownDenScale
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SOURCE: Modified from Paine 1981 INCOR PORATEO WILMINGTON, NOR TELL 9100 /392 -9253
ENVIRONMENTAL CONSULTANTS FAX [phone]
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Topsail Island Bridge 4 December 2013
Replacement SAV Survey CZR Incorporated
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Topsail Island Bridge (B -4929)
SAV Monitoring, Pender County, NC
SCALE: NOT TO SCALE APPROVED BY: DRAWN BY: BFG /TLJ
DATE: 11/08/13 FILE: CrownDenScale
4709 COLLEGE ACRES DRIVE
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SOURCE: Modified from Paine 1981 INCOR PORATEO WILMINGTON, NOR TELL 9100 /392 -9253
ENVIRONMENTAL CONSULTANTS FAX [phone]
CP #2234.00
FIGURE 2
Topsail Island Bridge 4 December 2013
Replacement SAV Survey CZR Incorporated

Table 1.Topsail Bridge SAV survey area (50 feet by 180 feet) corner coordinates
Survey Corner
Latitude
Longitude
Southeast
34.4310497
- 77.5522208
Northeast
34.4315403
- 77.5522532
Northwest
34.4315272
- 77.5524091
Southwest
34.4310341
- 77.5523780
Five observers, three CZR biologists and two representatives from NCDOT, were used during each
survey. Each observer was responsible for surveying a belt transect (5 feet by 45 feet) within each of
the 8 survey quadrats (25 feet by 45 feet)(Figure 3). The sequence in which the survey quadrats were
surveyed was determined by the tide and wind conditions; this prevented sediment suspended (by
wading observers) from further reducing visibility over the rest of the survey area. If the water depth
and turbidity allowed suitable visibility then the survey was accomplished using batiscopes and
underwater viewing buckets. However, when the depth of water and /or the turbidity increased,
observers crouched in the water and used their hands to feel for the presence of SAV. After each
quadrat, each observer reported the species, number of patches, and percent cover of SAV observed in
their survey area. Observer one measured water depth at the end of each quadrat adjacent to each
(outer) PVC marker. Reported depth was the average of the two depths measured adjacent to outside
PVC markers.
Results
Two estuarine SAV species, widgeon grass (Ruppia maritima) and eelgrass (Zostera marina), were rooted
in sediment throughout the survey area and all survey months (Figures 4 -7). Widgeon grass prefers a
moderate salinity (5 -18 PSU) but tolerates a wide range in salinity. Eelgrass is a species found in high
salinity (18 -30 PSU) estuarine areas (Deaton et al 2010).
Salinity measurements ranged from 30.18 to 36.68 PSU over the four surveys. The greatest Secchi
depth measured during a survey was greater than 20.5 inches. The area was not surveyed in October
due to the high spring tide water level, but the Secchi depth was measured at greater than 30.0 inches.
By the methodology, Secchi depth was measured at the same location as the water quality parameters,
and therefore was not measured in the deepest portion of the survey area. Thus, Secchi depths
reported from the survey are not necessarily good indicators of seawater clarity. Secchi measurements
were made prior to surveys as surveyors would often create a suspended cloud of silt and sediment
obscuring visibility until tidal currents dispersed. Water depth averages in the survey area ranged from
0.0 to 17.5 inches when the survey occurred in low tide conditions and 13.75 to 29.75 inches when the
survey occurred in high tide conditions (Table 2). In addition, increased and more widespread silt
deposition became evident throughout survey area in the August and September surveys.
Topsail Island Bridge 5 December 2013
Replacement SAV Survey CZR Incorporated

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Observer 2
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Quadrat (25'x45')
Observer 4
Observer 5
Survey Area Key
Topsail Island Bridge (B -4929)
SAV Monitoring, Pender County, NC
SCALE: NOT TO SCALE APPROVED BY: DRAWN BY: BFG /TLJ
NOT TO SCALE DATE: 11/08/13 FILE: SurveyAreaKey
Aw 4709 COLLEGE ACRES DRIVE CP #2234.00
SUITE 2
WILMINGTON, NORTH CAROLINA 28403
ENVIRONMENTT& CONSULTANTS FAX 910% FIGURE 3
392 -9139
Topsail Island Bridge 6 December 2013
Replacement SAV Survey CZR Incorporated

Presence of SAV Species*
Ruppia maritima
Zosfera marina
Both species
Absent
*all quadrats had less than 5% total SAV cover
Depth =3.0 in.
depth =19.5 in.
Depth =16.5 in.
depth =16.0 in,
04 June 2013
SAV Survey Results— Presence /Absence
Topsail Island Bridge (B -4929)
SAV Monitoring. Pender County, NC
SCALE: NOT TO SCALE APPROVED BY: DRAWN BY: BFG /TLJ
NOT TO SCALE DATE: 11/08/13 FILE: 04JUN13_SAV
Aw 4709 COLLEGE ACRES DRIVE CP #2234.00
SUITE 2
WILMINGTON, NORTH CAROLINA 28403
ENVIRONMENTT& CONSULTANTS FAX [phone] IGURE 4
392 -9139
Topsail Island Bridge 7 December 2013
Replacement SAV Survey CZR Incorporated

Depth =Q.O in.
Depth =17.5 in.
Depth =12.75 in.
Depth=B.O in.
Presence of SAV species *
Ruppia moritima
Zostera mar;na
Both species
Absent
*all quadrats had less than 5% total SAV cover
16 July 2013
SAV Survey Results— Presence /Absence
Topsail Island Bridge (B -4929)
SAV Monitoring, Pender County, NC
SCALE: NOT TO SCALE APPROVED BY: DRAWN BY: BFG /TLJ
NOT TO SCALE DATE: 12/03/13 1 FILE: 16Ju113_SAV
Aw 4709 COLLEGE ACRES DRIVE CP #2234.00
SUITE 2
WILMINGTON, NORTH CAROLINA 28403
ENVIRONMENTT& CONSULTANTS FAX [phone] IGURE 5
392 -9139
Topsail Island Bridge 8 December 2013
Replacement SAV Survey CZR Incorporated

Presence of SAV species*
Ruppiu maritr`ma
Zostera marina
Both species
Absent
*all quadrats had less than 5% total SAV cover
Depth =13.75 in.
Depth =29.75 in.
Depth =26.0 in.
Depth =24.0 in.
09 August 2013
SAV Survey Results— Presence /Absence
Topsail Island Bridge (B -4929)
SAV Monitoring. Pender County, NC
SCALE: NOT TO SCALE APPROVED BY: DRAWN BY: BFG /TLJ
NOT TO SCALE DATE: 12/03/13 1 FILE: 08Aug13_SAV
Aw 4709 COLLEGE ACRES DRIVE CP #2234.00
SUITE 2
WILMINGTON, NORTH CAROLINA 28403
ENVIRONMENTT& CONSULTANTS FAX [phone] IGURE 6
392 -9139
Topsail Island Bridge 9 December 2013
Replacement SAV Survey CZR Incorporated

Depth =0.0 in.
Depth =15.5 in.
Depth =15.0 in.
Depth= 101.25 in.
Presence of SAV species*
Ruppia moritima
Zostera marina
Both species
Absent
*all quadrats had less than 5% total SAV cover
12 September 2013
SAV Survey Results— Presence /Absence
Topsail Island Bridge (B -4929)
SAV Monitorin , Pender County, NC
SCALE: NOT TO SCALE APPROVED BY: DRAWN BY: BFG /TLJ
NOT TO SCALE DATE: 12/03/13 1 FILE: 12Sept13_SAV
4709 COLLEGE ACRE CP #2234.00
Z SUI ACRES
WILMINGTON, NORTEL09R10 /392 -9253 FIGURE 7
ENVIPONMENTAL CONSULTANTS FAX [phone]
Topsail Island Bridge 10 December 2013
Replacement SAV Survey CZR Incorporated

Table 2.Water quality parameters measured during SAV surveys in Topsail Sound.
Water Quality Parameters (recorded once at the northeastern corner of quadrat #8):
Secchi
Temp ( °C) DO% DO mg /L Sp Cond (µS) Cond (µS) Sal (PSU) pH
(in)1
Jun 25.3 61.4 4.18 52042 53320 34.25 7.81
>16.5
Jul 29.1 64.5 4.15 46668 50370 30.18 7.92
>13.5
Aug 28.6 59.2 3.78 54898 58636 36.25 7.71
>20.5
Sept 27.4 60.6 3.89 55462 57966 36.68 7.39
>10.0
Octz 22.5 84.5 6.01 50154 47610 32.87 7.71
>30.0
1Secchi depth was measured at the same location as the water quality parameters, and therefore
was not measured in the deepest area of the survey area.
2The October survey was not completed due to above normal (spring) tidal conditions and poor visibility.
Estimated actual aerial- coverage did not exceed 5 percent in any belt transect, or quadrat, for either
SAV species for all 2013 surveys When evaluating the number of belt transects with SAV detected, the
number of belt transects with SAV present was highest for both species in earlier surveys and declined
with each subsequent survey (Figures 4 through 7). SAV was detected from 39 of the 40 belt transects
(98 percent) in June and 11 of 40 belt transects (28 percent) in September. The frequency of
occurrence, or percentage of the total belt transects with SAV present, was higher for widgeon grass
compared to eelgrass (Figure 8).
Percentage of belt transects
with SAV present
100.0%
90.0%
u 80.0%
v
C c 70.0%
4 v 60.0%
v C
CL
> 50.0%
o Q
v 40.0%
3 30.0%
u
a 20.0%
10.0%
0.0%
Jun Jul Aug Sep
-- *- Zostera
fRuppia
Figure 8.Percentage of belt transects (40 total) with SAV present during four SAV surveys in 2013.
Topsail Island Bridge 11 December 2013
Replacement SAV Survey CZR Incorporated

During the June and July surveys, surveyors observed two to four patches each of both eelgrass and
widgeon grass approximately one to two feet in diameter. These larger patches were absent in
subsequent surveys, and smaller patches (less than one foot diameter) and many single sprigs and
rhizomes became the dominant forms of both SAV species. Many species of red and brown algae, as
well as bryozoans, formed visually apparent "beds" of vegetation that required closer inspection and
handling in order to differentiate these patches of vegetation from vascular SAV patches. These beds of
non - vascular species also were more apparent and appeared to be closely associated with SAV in the
earlier surveys. Coverage and presence of algae and bryozoans species, like the SAV, decreased
throughout the growing season. By the August and September surveys, no SAV patches were found,
and SAV was observed only as single sprigs /rhizomes. Many times surveyors had to distinguish between
actual rooted SAV rhizomes and the occurrence of SAV sprigs incorporated into worm casings
buried in sediment.
Summary
Widgeon grass (Ruppia maritima) and eelgrass (Zostera marina) were observed in the SAV survey area
of the Topsail Island bridge replacement project Alt 17 alignment during four monthly SAV surveys from
June to September 2013. Occurrences of both species decreased throughout the progression of the
growing season as expected and ranged from patches one to two feet in diameter to single sprigs or
rhizomes. Overall, widgeon grass presence was greater and declined later than eelgrass presence, and
neither species exceeded the less than 5 percent category in any sampling quadrat.
Topsail Island Bridge 12 December 2013
Replacement SAV Survey CZR Incorporated

Works Cited
Deaton, A.S., W.S. Chappell, K. Hart, J. O'Neal, B. Boutin. 2010. North Carolina Coastal Habitat
ProtectionPlan. North Carolina Department of Environment and Natural Resources. Division of
Marine Fisheries, NC. 639 pp.
Federal Highway Administration and North Carolina Department of Transportation. 2011.
Environmental Assessment for Topsail Island Bridge Replacement. Prepared by RS &H
Architects - Engineers - Planners, Inc. 2011.
Paine, David P. 1981. Aerial Photography and Image Interpretation for Resource Management. John
Wiley & Sons, Inc., New York City, NY. 571pp.
Topsail Island Bridge 13 December 2013
Replacement SAV Survey CZR Incorporated

:: View north into SAV survey area with quadrats marked, CZR, 04 June 2013
I=
:: Eelgrass observed through a view bucket, CZR, 04 June 2013
Topsail Island Bridge 14 December 2013
Replacement SAV Survey CZR Incorporated

L.-
:: Widgeon grass observed through a view bucket, CZR, 04 June 2013
:: Aquatic worm casings with SAV incorporated from survey area, CZR, 16 July 2013
Topsail Island Bridge 15 December 2013
Replacement SAV Survey CZR Incorporated