R-3113WM

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1 ANNUAL REPORT FOR 1999

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Pea Island Mitigatio
Dare County
Project No. 6.051029
TIP No. R-3113 WM
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Prepared By:
Natural Systems Unit &
Roadside Environmental Unit
North Carolina Department of Transportation
December 1999

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TABLE OF CONTENTS
SUMMARY ........................................................................................................... 1
1.0 INTRODUCTION ....................................................................................... 2
1.1 Project Description .......................................................................... 2
' 1.2 Purpose .......................................................................................... 2
1.3 Project History ................................................................................ 2
' 2.0 HYDROLOGY ............................................................................................4
2.1 Success Criteria ............................................................................ .. 4

' 2.2
2.3 Hydrologic Description .................................................................... 4
Results of Hydrologic Monitoring .................................................... 4
2.3.1 Site Data .............................................................................. 4
'
2.4 2.3.2 Climatic Data ........................................................................ 6
Conclusions .................................................................................... 8
3.0 VEG
3.1 ETATION ........................................................................................... 9
Success Criteria .............................................................................. 9
3.2 Vegetative Description .................................................................... 9
' 3.3 Results of Vegetative Monitoring ........................................... ..9
3.4 Conclusions.. . 10
4.0 OVERALL CONCLUSIONS/ RECOMMENDATIONS .......................... 11
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TABLES
TABLE 1 PRE-HURRICANE HYDROLOGIC MONITORING RESULTS .......... 6
TABLE 2 - POST HURRICANE HYDROLOGIC MONITORING RESULTS ........ 6
TABLE 3 - VEGETATIVE MONITORING RESULTS - AREA "A" ........................ 9
TABLE 4 - VEGETATIVE MONITORING RESULTS - AREA "B" ....................10
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FIGURE 1 - SITE LOCATION MAP ..................................................................... 3
FIGURE 2 - WELL LOCATION MAP .................................................................... 5
FIGURE 3 - 30-70 PERCENTILE GRAPH ........................................................... 7
APPENDICES
APPENDIX A - DEPTH TO GROUNDWATER PLOTS ...............................12
APPENDIX B - SITE PHOTOS ..............................................................18

SUMMARY
' The following report summarizes the monitoring activities that have occurred in the past
year at the Pea Island Mitigation Site. This site was established in March of 1996 and
' vegetative monitoring began in June of the same year. 1999 marks the 4t' year of
monitoring on this site. Mitigation plan specifications require this site to produce
vegetative and hydrological success for at least three growing seasons.
' The Pea Island site contains four wells one surface gauge, and one rain gauge. Three
of the four wells have been working without evidence of problems. Well number PI-5
had several malfunctions throughout the season. Data from mid May until the end of
September was not recorded from this well.
' The site's rain gauge, number PI-4, was noticed missing and was presumed to have
been washed out in mid-October. It will be replaced prior to the 2000 growing season.
' Hydrologic monitoring indicated that this site has met success criteria; the site was
completely inundated for most of. the growing season. Neither Hurricane Dennis nor
Floyd harmed the mitigation site. Both pre-hurricane and post-hurricane hydrologic
success data is included in this report. Vegetation monitoring yielded a successful
coverage of 73% across 10 planting transects. Because the site has met apparent
' success after four years, NCDOT proposes to discontinue all monitoring activities.

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1.0 INTRODUCTION
' 1.1 Project Description
' The Pea Island Mitigation Site, TIP# R-3113WM, is located in Dare County
approximately 3.5 miles south of Pea Island Refuge' maintenance facility, immediately
' west of NC 12 (Figure 1). The site consists of approximately 37.6 acres of wetland
establishment and is designed as mitigation for the relocation of NC 12.
' 1.2 Purpose
In order to demonstrate successful mitigation, hydrologic and vegetative monitoring
' must be conducted for a minimum of three consecutive years. Success criteria are
based on the federal guidelines for wetland mitigation. This guidelines stipulate criteria
for both hydrologic conditions and vegetation survival. The following report describes
' the results of the hydrologic and vegetative monitoring during the 1999 growing season
at the Pea Island Mitigation Site.

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Activities in 1999 reflect the 4th year of monitoring. Included in this report are analyses
of both hydrologic and vegetative monitoring results as well as local climate conditions
throughout the growing season.
1.3 Project History.
March 1996
June 1996
October 1996
June 1997
June- November 1997
September 1997
March- November 1998
August 1998
March- November 1999
October 1999
Site planted
Vegetation Monitoring (1 mo.).
Vegetation Monitoring (1 yr.)
Monitoring Wells Installed
Hydrologic Monitoring (1 yr.)
Vegetation Monitoring (2 yr.)
Hydrologic Monitoring (2 yr.)
Vegetation Monitoring (3 yr.)
Hydrologic Monitoring (3 yr.)
Vegetation Monitoring (4yr.)
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Pea Island Wetland Site &

Pea Island Duck Pond Site

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FIGURE 1
SITE LOCATION MAP
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I 2.0 HYDROLOGY
2.1 Success Criteria
' In accordance with federal guidelines for wetland mitigation, a site meets hydrologic
criteria if it is inundated or saturated (within 12" of the surface) by surface or ground
water for at least 12.5% of the growing season. However, discussions between
' NCDOT and natural resource agencies have determined that, due to the unique
character of this site, the normal guidelines for hydrologic success may not apply.
' Groundwater levels may vary significantly on a daily basis due to a sandy substrate that
is in close proximity to a tidally influenced body of water.
' The growing season in Dare County begins March 13 and ends November 25. These
dates correspond to a 50% probability that air temperatures will drop to 28° or lower
after March 13 and before November 25.' Thus the growing season is 258 days;
optimum wetland hydrology requires 12.5% of this growing season, or 32 days. The
site must also experience average climatic conditions in order for the hydrologic data to
be considered valid.
' 2.2 Hydrologic Description
' Four monitoring wells, one rain gauge, and one surface water gauge were installed on
surface
' water gauge in 1999. Precipitation events are included on each graph as bars. The
maximum number of consecutive days is noted on each graph. The individual
' precipitation events, shown on the monitoring well graphs as bars, represent data
collected from a Manteo weather station, maintained by the NC State Climate Office.
These graphs include rain data from March to August of 1999.
' 2.3 Results of Hydrologic Monitoring
-
the depth to groundwater and rainfall, respectively. Data was collected on a daily basis
site in Appendix June A 1997 contains a (Figure 2)plot. of The the water automatic depth for monitoring each wells and monitoring rain well and gauges record
throughout the growing season.
'
1 2.3.1 Site Data
The largest number of consecutive days in which the groundwater was within twelve
inches of the surface was determined for each well. The number of days was then
converted into a percentage of the 258-day growing season. The results are presented
in Table 1 and Table 2. With Hurricanes Dennis and Floyd this past fall, groundwater
' Soil Conservation Service. Soil Survey of Dare County, North Carolina, p.69.
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levels were abnormally influenced during the early part of September. Therefore pre-
hurricane data and post hurricane data was analyzed separately.
TABLE 1
HYDROLOGIC MONITORING RESULTS
FOR MARCH 13.1999-AUGUST 31. 19994PRE-HURRICANE INFLUENCEI
Monitoring
Well < 5% 5% - 8% 8% - 12.5% > 12.5% Actual % Success
Dates
PI-2 66.6 March 13 -August 31
PI-3 16.6 March 13 - April 24
PI-5 8.1 April 23 - May 13
PI-6 15.1 March 13 - April 20
TABLE 2
HYDROLOGIC MONITORING RESULTS
SEPTEMBER 1-NOVEMBER 25. 1999 (POST HURRICANE INFLUENCE)
Monitoring
Well < 5% 5% -80/. -12.5% > 12.5% Actual °/U Success
Dates
PI-2 ? 33.3 September 1 - November 25
PI-3 33.3 September 1 - November 25
PI-5 19.4 September 25 - November 13
PI-6 29.1 September 1 - November 14
This site data shows a record of saturation for more than 12.5% of the growing season
in three of the four wells. Both pre-hurricane and post hurricane success supports the
conclusion that this site continues to meet jurisdictional success. The surface gauge
has shown a consistent level of surface water throughout the growing season.
Due to a malfunctioning monitoring well, the groundwater data for one well is
incomplete. Data from well number PI-5 is missing data from May 16 through
September 24. The well was replaced on the 25th of September and is now functioning
properly. Rain gauge number PI-4 was noticed missing, in an October site visit. It was
presumed to be washed out and will be replaced prior to the start of the 2000 season.
2.3.2 Climatic Data
Figure 3 represents an examination of the local climate in comparison with historical
data in order to determine whether 1999 was "average" in terms of climate conditions.
The figure compares the rainfall from 1998 and 1999 with that of historical rainfall (data
collected between 1966 and 1997).
The two lines represent the 30th and 70th percentiles of historical monthly precipitation
for Manteo, NC. The bars represent the monthly rainfall totals for the winter months of
1998 and the available months of this year. All rainfall data was collected from the NC
State Climate Office. The graph shows rainfall totals through August 1999. Rainfall
data for the winter of 1999 will be presented in the 2000 Annual Monitoring Report.
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FIGURE 3
30-70 PERCENTILE GRAPH

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This growing season's climate was average for the area. Even with an excessive
amount of rain during September, the site experienced no extended periods of
abnormally dry or wet weather.
2.4 Conclusions
This site has exceeded success criteria again this season; the site showed surface
water for the majority of the season. Three of the four monitoring stations yielded
wetland hydrology; the remaining well malfunctioned, thus not taking readings the entire
growing season.
Pea Island was not adversely affected by Hurricanes Dennis or Floyd, which hit the
state in September 1999. The site's integrity was maintained, and the wells were not
disturbed. The rain gauge, which was missing and presumed to be washed out in mid
October was not due to the hurricanes.
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3.0 VEGETATION
3.1 Success Criteria
Success Criteria states that there should be > 50% areal coverage of grasses and other
herbaceous vegetative species for a period of at least three years.
3.2 Description of Species
The following species were planted in the Wetland Restoration Area:
Panicum amarum
Panicum amarulum
Scirpus americanus
Scirpus robustus
Scirpus olneyi
Bidens aristosa
3.3 Results of Vegetation Monitoring (4 year)
Area "A"

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1 15% 30% 20% 10% 75%
2 20% 8% 25% 25% 5% 2% 5% 90%
9 35% 20% 15% 10% 80%
AVERAGE COVER (%) 82%
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Area "B"
3 40% 15% 5% 60%
4 20% 20% 35% 5% 80%
5 10% 25% 25% 60%
6 5% 50% 15% 70%
7 5% 30% 30% 5% 70%
8 20% 20% 40% 5% 5% 90%
10 25% 20% 5% 50%
AVERAGE COVER (%) 69%
TOTAL AVERAGE COVER (%) 73%
3.4 Conclusions
There are 36.7 acres of marsh established on this site. There were 10 monitoring plots
established throughout the site, three within the area "A" and seven within area "B".
The average aerial coverage of grasses in area "A" is 82%. The average aerial
coverage of the grasses in area "B" is 69%. The total average cover is 73%, which
exceeds the Success Criteria for this site.
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4.0 OVERALL CONCLUSIONS/ RECOMMENDATIONS
After four years of vegetation monitoring and three years of hydrologic monitoring, the
site has met success criteria. The site showed successful hydrologic conditions as well
as an average plant coverage of 73%.
NCDOT recommends discontinuing all monitoring activities at the site.
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APPENDIX A
DEPTH TO GROUNDWATER PLOTS
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APPENDIX B
SITE PHOTOS
18

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PEA ISLAND
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Photo 1: Eastern side of site facing West
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Photo 2: Middle of site facing NW at Plot 8
Photo 3: Middle of site facing NW at Plot 7
PEA ISLAND
Photo 4: Facing East at Plot 1
Photo 5: Facing East at Plot 4
7777`-7'_1
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NCDENR
JAMESZ..HUNT . JR.:
-GOVERNOR
BILL,HOLMAN
SECRETARY
August 1, 2000
INW NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF COASTAL MANAGEMENT
V. Charles Bruton, Ph.D.
Assistant Branch Manager
Project Development and Environmental Analysis
NC Department of Transportation
1548 Mail Service Center
Raleigh, NC 27699-1548
Tit
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SUBJECT: Pea Island Mitigation Site, Dare County, State Project No. 6.051029,
TIP No. R-3113WM, COE Action ID No. 199404858. CAMA Permit No. 40-95.
"DONNA D. MOFFITT
DIRECTOR Dr. Bruton.
This letter is in response to letters dated September 15, 1999 and May 8, 2000 from
the NC Department of Transportation (NC DOT) to the NC Division of Coastal
Management (NC DCM) regarding the above referenced project.._.
The September 15`h NC DOT letter requests a modification to the revised
mitigation plan for the Pea Island mitigation site dated February 1995 for the
proposed relocation of NC 12 from four miles south of Oregon Inlet to six miles
south of Oregon Inlet in Dare County, TIP No. R-3113. The current monitoring.
plan for the site targets a vegetation success criteria of >50% of the plants living for
at least 3 years. The monitoring methodology contained within the plan indicated
that a determination of number of plants per acre would be made through the use of
ten 15 feet square sample plots.
NC DCM hereby approves NC DOT's proposal that the monitoring plan for the Pea
Island Mitigation Site be revised to state that vegetative success criteria will be
>50% areal coverage of grasses and other herbaceous vegetative species for a
period of at least three years. Vegetation will be monitored in the previously
established ten 15-feet square. plots. A determination of plants per acre is no longer
required. Condition No. 8 of the CAMA Permit for this project requires that
- monitoring is conducted to attest evolution of wetland vegetation and hydrology.
Because the CAMA Permit does not specifically identify the monitoring
methodology, a CAMA permit modification is not required.
The May 8t' NC DOT letter requests discontinuing monitoring of the Pea Island
mitigation site. It appears, according to the information provided in your letter and
in the 1999 annual monitoring report, that the vegetation and hydrologic success
criteria have been met. We can, therefore, agree with your recommendation to
discontinue monitoring at this site.
MAILING: 1638 MAIL SERVICE CENTER, RALEIGH, NORTH CAROLINA 27699-1638
PHYSICAL: 2728 CAPITAL BLVD., RALEIGH, NC 27604
PHONE: [phone] FAX: [phone]
AN EQUAL OPPORTUNITY / AFFIRMATIVE ACTION EMPLOYER - 50% RECYCLED / 10% POST-CONSUMER PAPER
:ENR TOLL FREE HOTLINE: [phone]
We are pleased the site has exceeded the success criteria as specified in the revised
mitigation plan dated February 1995: (1) vegetation coverage of >50% plants
living for at least 3 years; and (2) hydrologic success criteria of soil saturation to
within 12 inches of the surface for at least 12.5% of the•growing season.
If you have any questions or concerns, please contact Kelly Williams or me at (919)
733-2293.
Sincerely,
c
Cathy Brittingham
Transportation Project Coordinator
cc: Mike Bell, USACE
David Cox, NC WRC
John Hennessy, NC DWQ
Heather Montague, NC DOT
Beth Smyre, NC DOT
Kelly Williams, P.W.S., DCM

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STATE OF NORTH CAROLINA
DEPARTNffiNT OF TRANSPORTATION
JAMES B. HUNT 1R. P.O. BOX 25201, RALEIGH, N.C. 27611-5201 DAVID MCCOY
GOVERNOR SECRETARY
September 15, 1999
U.S. Army Corps of Engineers
Washington Regulatory Field Office
Post Office Box 1000
Washington, NC 27889-1000
ATTENTION: Mr. Mike Bell
NCDOT Coordinator
Dear Mr. Bell:
SUBJECT: Permit Modification: Pea Island Mitigation Site, Dare County, State
Project No. 6.051029, TIP R-3113WM COE Action ID No. 199404858.
The North Carolina Department of Transportation (NCDOT) requests a
modification to the Mitigation Plan (February 1995) for the Pea Island Mitigation Site in
Dare County. The specific modification is with regard to monitoring methodologies for
determination of vegetative success of the site.
The current Monitoring Plan for the site targets a success criteria of > 50 % of the
plants living for at least three years. The monitoring methodology contained within the
plan indicated that a determination of number of plants per acre would be made through
the use of ten-15 feet square sample plots.
A conflict lies -between the monitoring methodology and the type of vegetation
planted. A determination of plants per acre is more appropriate for woody species of
vegetation. The Pea Island Mitigation site was planted with grasses and other herbaceous
species where a per cent areal cover determination is more appropriate ("Corps of
Engineers Wetlands Delineation Manual", 1987).
Therefore, the NCDOT requests that the Monitoring Plan for the Pea Island
Mitigation Site be revised to state that vegetative success criteria will be > 50 % areal
coverage of grasses and other herbaceous vegetative species for a period of at least three
years. Vegetation will be monitored in the previously established ten-15 feet square
monitoring plots.
Thank you for your assistance with this project. If you have any questions or
need additional information, please contact Mr. Bruce Ellis at [phone].
Sincerely,

?u William D. Gilmore, PE, Branch Manager
Planning Development and
Environmental Analysis Branch
cc: Mr. Doug Huggett, NCDCM, Raleigh
Mr. David Franklin, Corps of Engineers, Wilmington Field Office
Mr. John Dorney, NCDENR, Division of Water Quality
Mr. David Cox, NCWRC
Mr. Calvin Leggett, P.E., Program Development Branch
Ms. Debbie Barbour, P.E., Highway Design Branch
Mr. A. L. Hankins, P.E., Hydraulics Unit
Mr. William J. Rogers, P.E., Structure Design Unit
Mr. John Alford, P.E., Roadway Design Unit
Mr. D. R. Conner, PE, Division 1 Engineer
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STATE OF NORTH CAROLINA
DEPARTMENT OF TRANSPORTATION
JAMES B. HUNT JR. P.O.13OX 25201, RALEIGH, N.C. 27611-5201 DAVID MCCOY
GOVERNOR SECRETARY
September 15, 1999
U.S. Army Corps of Engineers
Washington Regulatory Field Office
Post Office Box 1000
Washington, NC 27889-1000
ATTENTION: Mr. Mike Bell
NCDOT Coordinator
Dear Mr. Bell:
SUBJECT: Permit Modification: Pea Island Mitigation Site, Dare County, State
Project No. 6.051029, TIP R-3113WM COE Action ID No. 199404858.
The North Carolina Department of Transportation (NCDOT) requests a
modification to the Mitigation Plan (February 1995) for the Pea Island Mitigation Site in
Dare County. The specific modification is with regard to monitoring methodologies for
determination of vegetative success of the site.
The current Monitoring Plan for the site targets a success criteria of > 50 % of the
plants living for at least three years. The monitoring methodology contained within the
plan indicated that a determination of number of plants per acre would be made through
the use of ten-15 feet square sample plots.
A conflict lies between the monitoring methodology and the type of vegetation
planted. A determination of plants per acre is more appropriate for woody species of
vegetation. The Pea Island Mitigation site was planted with grasses and other herbaceous
species where a per cent areal cover determination is more appropriate ("Corps of
Engineers Wetlands Delineation Manual", 1987).
Therefore, the NCDOT requests that the Monitoring Plan for the Pea Island
Mitigation Site be revised to state that vegetative success criteria will be > 50 % areal
coverage of grasses and other herbaceous vegetative species for a period of at least three
years. Vegetation will be monitored in the previously established ten-15 feet square
monitoring plots.
A
Thank you for your assistance with this project. If you have any questions or
need additional information, please contact Mr. Bruce Ellis at [phone].
Sincerely,

?v William D. Gilmore, PE, Branch Manager
Planning Development and
Environmental Analysis Branch
cc: Mr. Doug Huggett, NCDCM, Raleigh
Mr. David Franklin, Corps of Engineers, Wilmington Field Office
Mr. John Dorney, NCDENR, Division of Water Quality
Mr. David Cox, NCWRC
Mr. Calvin Leggett, P.E., Program Development Branch
Ms. Debbie Barbour, P.E., Highway Design Branch
Mr. A. L. Hankins, P.E., Hydraulics Unit
Mr. William J. Rogers, P.E., Structure Design Unit
Mr. John Alford, P.E., Roadway Design Unit
Mr. D. R. Conner, PE, Division 1 Engineer