ANNUAL REPORT FOR 2000
U. S. Marine Corps Mitigation Site
Onslow County
Project No. 6.269010T
TIP No. U-2107 WM
Prepared By:
Natural Systems Unit & Roadside Environmental Unit
North Carolina Department of Transportation
December 2000
TABLE OF CONTENTS
SUMMARY………………………………………………………………………………………1
1.0 INTRODUCTION………………………………………………………………………..2
1.1 Project Description………………………………...……………………………2
1.2 Purpose……….…..………………………………...…………………………..2
1.3 History…………….………………………………...……………………………2
2.0 HYDROLOGY…………………………………………………………….……………..4
2.1 Success Criteria….………………………………...……………...……………4
2.2 Hydrologic Description…………………………...…………………….………4
2.3 Results of Hydrologic Monitoring………………...……………………………4
2.3.1 Site Data…………………………………………………………………4
2.3.2 Climatic Data…………………………………………………………….6
2.4 Conclusions………………………………………...…………………………7
3.0 VEGETATION.………………………………………………………...……..……….10
3.1 A Success Criteria (shrub area)……..…………………………...……………10
3.1 B Success Criteria (marsh grass area)…………..…………………………...10
3.2 A Description of Planted Areas (shrub area)………………………………….10
3.2 B Description of Planted Areas (marsh grass area)………………………….10
3.3 A Results of Vegetation Monitoring (shrub area)……………………………..11
3.3 B Results of Vegetation Monitoring (marsh grass area)……………...……..12
3.4 A Conclusions (shrub area)……………………………………………………..13
3.4 B Conclusions (marsh grass area)……………...……………………………..13
4.0 OVERALL CONCLUSIONS / RECOMMENDATIONS….……………..………….14
TABLES
TABLE 1 – RESULTS OF HYDROLOGIC MONITORING…………………………………6
TABLE 2 – VEGETATION MONITORING RESULTS (shrub area)……………………..11
TABLE 3 – VEGETATION MONITORING RESULTS (marsh grass area)……………..12
FIGURES
FIGURE 1 – SITE LOCATION MAP……………….…….………….………………………..3
FIGURE 2 – WELL LOCATION
MAP………………………………………………………………………………………………5
FIGURE 3 – 2000 HYDROLOGIC MONITORING RESULTS……………………………..8
FIGURE 4 - 30-70 PERCENTILE GRAPH………………………………………………….9
APPENDICES
APPENDIX A – DEPTH TO GROUNDWATER GRAPHS…………………..…………...15
APPENDIX B – SITE PHOTOS…………..…………………………………………………27
APPENDIX C – VEGETATION PLANTING PLAN………..………………………………30
1
SUMMARY
The following report summarizes the monitoring activities that have occurred in the past
year at the U.S. Marine Corps Mitigation Site. This site was constructed in 1999.
Monitoring activities in 2000 represent the second year of monitoring. The site must
demonstrate vegetation success for three years and hydrologic monitoring must be
conducted until success is demonstrated.
The site is monitored with twenty five vegetation plots, three groundwater gauges, four
surface gauges, and one rain gauge.
One major change in the hydrologic monitoring process is the installation of an Infinity
rain gauge. This gauge was installed because in the past existing on-site rainfall
gauges have proven unreliable. Daily rainfall recorded at a Trenton rain gauge,
maintained by the NC State Climate Office will be obtained to produce the 30-70
percentile graph. Data from the Infinity rain gauge will be used for comparison on the
groundwater gauge graphs.
Hydrologic monitoring indicates that the site has met success criteria during the1999
monitoring year. All three groundwater gauges met criteria for well over 12.5% of the
growing season and two of the four surface water gauges have shown standing surface
water throughout the growing season. Gauge 1 malfunctioned for most of the growing
season and gauge 7 did not show appreciable surface water during the growing
season.
Vegetation monitoring of the shrub area revealed an average density of 573 shrubs per
acre, well above the minimum requirement. Vegetation monitoring yielded results
below the success criteria in the marsh grass planting transects, although has improved
since 1999.
Based on the monitoring results from the 2000 season and consulting with resource
agencies, NCDOT has determined that remediation of the site is necessary. Grading of
the site will take place in the winter of 2002 and the site will be replanted in the spring of
2002. Tidal data will be obtained by recording the presence of surface water on site
every hour for one month during the growing season in 2001 to determine whether the
site is being flooded twice a day.
2
1.0 INTRODUCTION
1.1 Project Description
The U.S. Marine Corp Mitigation Site encompasses 3.5 acres and is located in Onslow
County on the Intracoastal Waterway southeast of Onslow Beach at the Camp Lejeune
Marine Corps Base (Figure 1). Designed as a salt marsh, the site provides
compensatory mitigation for the US 17 Bypass of Jacksonville.
1.2 Purpose
In order to demonstrate successful mitigation, USMC is monitored for both wetland
vegetation and hydrology. Vegetative monitoring must be conducted for a minimum of
three years, and hydrologic monitoring must be conducted until success is
demonstrated. The following report details the results of hydrologic and vegetative
monitoring during 2000 at the USMC Mitigation Site.
1.3 Project History
March 1999 Grading Construction
April 1999 Site planted
May 1999 Monitoring Wells Installed
March- November 1999 Hydrologic Monitoring (1 yr.)
October 1999 Vegetation Monitoring (1 yr.)
March-November 2000 Hydrologic Monitoring (2 yr.)
August 2000 Vegetation Monitoring (2 yr.)
3
4
2.0 HYDROLOGY
2.1 Success Criteria
Project specifications require saturation or inundation (within 12 inches of the surface)
for at least 27 consecutive days during the growing season for one year under
reasonably average climatic conditions. However, areas may still be classified as
wetlands even though the hydrology does not meet optimum wetland criteria.
The growing season in Onslow County begins April 8 and ends November 5. These
dates correspond to a 50% probability that air temperatures will drop to 28° F or lower
after April 8 and before November 5.1 Thus, the growing season is 212 days. Also,
local climate conditions must represent average conditions for the area.
2.2 Monitoring Procedure
Three monitoring gauges, one rain gauge, and four surface water gauges were installed
on-site in 1999 (Figure 2). The automatic groundwater gauges and rain gauges record
depth to groundwater and rainfall, respectively. Daily readings are taken throughout the
growing season. The rain gauge was replaced in the spring of 2000 with an Infinity
rain gauge.
Appendix A contains a plot of the water depth for each groundwater monitoring gauge
and surface gauge during the growing season. Precipitation events are included on
each groundwater gauge graphs as bars. The precipitation data on each groundwater
gauge graph is from the on-site Infinity rain gauge.
2.3 Results of Hydrologic Monitoring
2.3.1 Site Data
The maximum number of consecutive days that the groundwater was within twelve
inches of the surface was determined for each gauge. This number was converted into
a percentage of the 212-day growing season. Based on project requirements, the
optimum percentage, which represents 27 consecutive days of the growing season, is
12.5%.
1 Soil Conservation Service, Soil Survey of Johnston County, North Carolina, 1994.
5
6
The following table presents both the actual consecutive day percentage for each
gauge as well as its percentage range.
Table 1
RESULTS OF HYDROLGIC MONITORING 2000
Monitoring
Gauge
< 5% 5% - 8% 8% - 11.5% > 11.5% Actual % Success Dates
G3^ ✔ 100.0 Apr. 8 – Nov. 5
G4* ✔ 100.0 Apr. 8 – Nov. 5
G5* ✔ 100.0 Apr. 8 – Nov. 5
‘*’ - Denotes wells which malfunctioned during the growing season; well data is
incomplete.
‘^’ - Denotes consecutive days extending into the second half of the growing season.
For 2000, all three groundwater gauges indicate hydrologic data that meets and
exceeds project specifications. Two of the four surface water gauges on the site have
shown appreciable surface water throughout the 2000 growing season. Surface gauge
1 malfunctioned a large portion of the growing season, which rendered the data
received invalid. The July download revealed a dead battery for gauge 1, which was
replaced. Gauge 1 stopped recording each month after that due to a dead battery and
each time the battery was replaced and the gauge reset. On November 7 it was
determined that gauge 1 was not functioning properly and at that time the entire gauge
was replaced and the monitoring intervals reset. Surface gauge 7 showed minimal
surface water throughout the growing season. In order to clearly view daily flooding of
the site, a graph for one week out of the growing season in addition to a graph for the
entire growing season is included for each surface gauge. Figure 3 is a map of the
hydrologic monitoring results for 2000. A blue dot indicates hydrology for greater than
12.5% of the growing season; a red dot means the gauge showed between 8% and
12.5%. A green dot indicates hydrology between 5% and 8% of the season.
2.3.2 Climatic Data
Figure 4 is a comparison of 1999 and 2000 monthly rainfall to historical precipitation for
the area. The two lines represent the 30th and 70th percentiles of monthly precipitation
for Trenton, NC. These percentiles represent monthly rainfall data collected in Trenton
between 1931 and 1998. They are designed to illustrate the “normal range” for rainfall
in the area. The bars are the monthly rainfall totals for 1999 and 2000. The historical
data was collected from a National Climatic Data Center rain gauge; the current
monthly rainfall data was provided by the State Climate Office of North Carolina at NC
State University. Because of data availability, the 2000 rainfall encompasses
precipitation through October.
7
Rainfall during 2000 was for the most part average for the Trenton area. The 2001
Annual Monitoring Report will show precipitation totals for the remaining months of
2000.
2.4 Conclusions
In 2000, all three groundwater gauges exceeded project specifications. Although,
according to the surface gauges the site is not receiving substantial flooding to support
the desired vegetation and meet the hydrology success criteria.
8
9
USMC 30-70 Graph
Trenton, NC
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec
Month
Precipitation (in.)
2000 Rainfall 1999 Rainfall 30% 70%
70th Percentile
30th Percentile
10
3.0 VEGETATION: USMC MITIGATION SITE (YEAR 2 OF 3)
3.1A Success Criteria (Shrub Area)
Success Criteria states that there must be a minimum mean density of 320 trees per
acre of approved target species surviving for at least three years
3.1B Success Criteria (Marsh Grass Area)
The vegetative marsh success of the wetland site will be determined in accordance with
NMFS Guidelines. Monitoring plots found to be located within the open water channel
will not be evaluated, and will not count to the final count of plots. The vegetation
component of the wetland site will be deemed successful if the following criteria are
met.
1. At year five, the average of all plots should have a scale value of 5 (75%
vegetative cover) consisting of wetland herbaceous species, not including
any invasive species.
2. A minimum of 70% of the plots shall contain the target (planted) specie.
3.2A Description of Planted Areas (Shrub Area)
The following plant communities were planted in the Shrub Area:
Zone 1: (approximately 0.56 acres)
Myrica cerifera, Wax Myrtle
Baccharis halimifloia, False Willow
Iva frutescens, Marsh Elder
3.2B Description of Planted Areas (Marsh Grass Area)
The following plant communities were planted in the Marsh Grass Area:
Zone 1: (approximately 0.7acres)
Juncus roemerianus, Black Needle Rush
Zone 2: (approximately 2.23 acres)
Spartina alterniflora, Smooth Cordgrass
11
3.3A Results of Vegetation Monitoring (2 year) (Shrub Area)
Table 2
1 24 8 11 43 51 51 573
TOTAL DENSITY 573
To determine shrub density, 50’ x 50’ plots are installed immediately following planting.
The actual number of planted shrubs which occur within the plot are counted. This
number is equated to the number within each plot, which represents 680 shrubs per
acre (average). The survival monitoring number is compared to the planted number to
obtain survival percentage. This percentage is applied to the 680 shrubs per acre to
obtain an estimated shrub per acre for the site. (Density = monitoring count / planted
shrubs x 680)
Site Notes: Natural propagation seen in Marsh elder species. Wax myrtles have
some salt burn. Patens and juncus present in zone. Alterniflora is present in the
channel. Phragmities on the outer fringe of the site will be treated.
12
3.3B Results of Vegetation Monitoring (Marsh Grass Area)
Table 3
N otes
2 1 3.0 ✔ ✔
2 2 0.5 ✔ ✔
1 3 2.0 ✔ ✔ S ide F in g e r
2 4 2.0 ✔ ✔
2 5 0.0
2 6 0.5 ✔ ✔ 5" Sur face W a ter
2 7 0.0
2 8 0.0
1 9 0.0
2 10 2 .0 ✔ ✔ 1 2 " Su rfac e W a ter
2 11 4 .0 ✔ ✔ 8" Sur face W a ter
2 12 2 .0 ✔ ✔
1 13 5 .0 Pa tens
2 14 5 .0 ✔ ✔ 2" Sur face W a ter
2 15 3 .0 ✔ ✔ 6" Sur face W a ter
2 16 4 .0 ✔ ✔ 6" Sur face W a ter
1 17 3 .0 ✔ ✔ B la ck N eed le R ush & P a ten s
2 18 0 .0
2 19 0 .0
2 20 5 .0 ✔ ✔ 8" Sur face W a ter
2 21 0 .0
2 22 3 .0 ✔ ✔ 6" Sur face W a ter
2 23 5 .0 Pa tens
2 24 2 .0 ✔ ✔ 6" Sur face W a ter
2 25 0 .0
2 26 0 .0
2 27 4 .0 ✔ ✔ 6" Sur face W a ter
2 28 4 .0 ✔ ✔ 6" Sur face W a ter
1 29 0 .0
1 30 0 .0
1 31 0 .0
2 32 5 .0 ✔ ✔ 6" Sur face W a ter
1 33 2 .0 ✔ ✔
1 34 2 .0 ✔ ✔
2 35 0 .0
2 36 1 .0 ✔ ✔ 4" Sur face W a ter
1 37 0 .0
2 38 0 .0
2 39 2 .0 ✔ ✔
1 40 0 .0
2 41 4 .0 ✔ ✔ 4" Sur face W a ter
2 42 0 .0
2 43 5 .0 Pa tens
2 44 0 .0
2 45 3 .0 ✔ ✔
A VG . 1 .8
Fr equ en cy /Per cen tage o f 5 3 .3%
P lots with D e s ired Sp ec ie
Sum B -B Value 8 3 .0
Total # o f P lo ts C ounted 4 5.00
V egeta tive Cov er (S ca le V a lu e) 1 .84
13
Site Notes: Marsh area has grasses present throughout most of the site, and coverage
is increasing.
3.4A Conclusions (Shrub Area)
Of the 3.5 acres of this site, approximately 0.56 acres involved shrub planting. There
was 1 test plot established in the planting area. The second year vegetation monitoring
of the planted area revealed an average density to be 573 shrubs per acre, which is
well above the minimum requirement of 320 shrubs per acre. The wax myrtle continue
to show slight salt burn and the marsh elder shrubs are spreading by natural
propagation throughout the shrub area.
3.4B Conclusions (Marsh Grass Area)
• Percent Frequency of Target Specie (Black needle rush and Smooth Cordgrass)
53.3%
Frequency of 70% required.
• Vegetative Cover Scale Value 1.8
Scale Value of 5 required for year 5.
Of the 3.5 acres of this site, approximately 2.93 acres involved marsh grass planting.
There were 45 random plots established throughout the planting area and located using
GPS. The vegetative coverage and frequency do not meet the success criteria;
however, they have significantly increased since planting.
14
4.0 OVERALL CONCLUSIONS/ RECOMMENDATIONS
According to project specifications the hydrology and vegetation of the site have not
demonstrated success. This concludes the second year of vegetation and hydrological
monitoring for the site.
Based on the monitoring results from the 2000 season and consulting with resource
agencies at an on-site meeting November 28, 2000, NCDOT has determined that
remediation of the site is necessary. Grading of the site will take place in the winter of
2002 and the site will be replanted in the spring of 2002. Tidal data will be obtained by
recording the presence of surface water on site every hour for one month during the
growing season in 2001 to determine whether the site is being flooded twice a day.
The three year monitoring period will begin when remediaiton efforts are finished
15
APPENDIX A
DEPTH TO GROUNDWATER PLOTS
16
USMC-G3
-20
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
2
4
6
8
08-Apr-00
15-Apr-00
22-Apr-00
29-Apr-00
06-May-00
13-May-00
20-May-00
27-May-00
03-Jun-00
10-Jun-00
17-Jun-00
24-Jun-00
01-Jul-00
08-Jul-00
15-Jul-00
22-Jul-00
29-Jul-00
03-Aug-00
10-Aug-00
17-Aug-00
24-Aug-00
31-Aug-00
07-Sep-00
14-Sep-00
21-Sep-00
28-Sep-00
05-Oct-00
12-Oct-00
19-Oct-00
26-Oct-00
02-Nov-00
Date
Depth to Groundwater (in.)
0
1
2
3
4
Precipitation (in.)
Rainfall S31FA85 USMC-G3 Required Depth
212 days
17
USMC-G4
-20
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
2
4
6
8
08-Apr-00
15-Apr-00
22-Apr-00
29-Apr-00
06-May-00
13-May-00
20-May-00
27-May-00
03-Jun-00
10-Jun-00
17-Jun-00
24-Jun-00
01-Jul-00
08-Jul-00
15-Jul-00
22-Jul-00
29-Jul-00
03-Aug-00
10-Aug-00
17-Aug-00
24-Aug-00
31-Aug-00
07-Sep-00
14-Sep-00
21-Sep-00
28-Sep-00
05-Oct-00
12-Oct-00
19-Oct-00
26-Oct-00
02-Nov-00
Date
Depth to Groundwater (in.)
0
1
2
3
4
Precipitation (in.)
Rainfall S127164 USMC-G4 Required Depth
212 days
18
USMC-G5
-20
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
2
4
6
8
08-Apr-00
15-Apr-00
22-Apr-00
29-Apr-00
06-May-00
13-May-00
20-May-00
27-May-00
03-Jun-00
10-Jun-00
17-Jun-00
24-Jun-00
01-Jul-00
08-Jul-00
15-Jul-00
22-Jul-00
29-Jul-00
03-Aug-00
10-Aug-00
17-Aug-00
24-Aug-00
31-Aug-00
07-Sep-00
14-Sep-00
21-Sep-00
28-Sep-00
05-Oct-00
12-Oct-00
19-Oct-00
26-Oct-00
02-Nov-00
Date
Depth to Groundwater (in.)
0
1
2
3
4
Precipitation (in.)
Rainfall S1270CF USMC-G5 Required Depth
212 days
19
USMC-1
Surface Gauge
0
2
4
6
8
10
12
14
16
08-Apr-00
14-Apr-00
21-Apr-00
27-Apr-00
04-May-00
11-May-00
17-May-00
24-May-00
31-May-00
06-Jun-00
13-Jun-00
19-Jun-00
26-Jun-00
03-Jul-00
09-Jul-00
16-Jul-00
22-Jul-00
29-Jul-00
05-Aug-00
11-Aug-00
18-Aug-00
25-Aug-00
31-Aug-00
07-Sep-00
13-Sep-00
20-Sep-00
27-Sep-00
Date
Surface Water Depth (in.)
gauge
malfunction
gauge malfunction
20
USMC-1
Surface Gauge
0
1
2
3
4
5
6
7
8
9
14-Apr-00
14-Apr-00
14-Apr-00
14-Apr-00
15-Apr-00
15-Apr-00
15-Apr-00
15-Apr-00
16-Apr-00
16-Apr-00
16-Apr-00
16-Apr-00
17-Apr-00
17-Apr-00
17-Apr-00
17-Apr-00
18-Apr-00
18-Apr-00
18-Apr-00
18-Apr-00
19-Apr-00
19-Apr-00
19-Apr-00
19-Apr-00
20-Apr-00
20-Apr-00
20-Apr-00
20-Apr-00
Date
Depth of Surface Water (in.)
21
USMC-2
Surface Gauge
0
2
4
6
8
10
12
14
16
08-Apr-00
14-Apr-00
21-Apr-00
28-Apr-00
05-May-00
12-May-00
19-May-00
26-May-00
02-Jun-00
08-Jun-00
15-Jun-00
22-Jun-00
29-Jun-00
06-Jul-00
13-Jul-00
20-Jul-00
27-Jul-00
02-Aug-00
09-Aug-00
16-Aug-00
23-Aug-00
30-Aug-00
06-Sep-00
13-Sep-00
20-Sep-00
26-Sep-00
03-Oct-00
02-Oct-00
09-Oct-00
16-Oct-00
23-Oct-00
30-Oct-00
Date
Surface Water Depth (in.)
22
USMC-2
Surface Gauge
0
1
2
3
4
5
6
7
14-Apr-00
14-Apr-00
14-Apr-00
14-Apr-00
15-Apr-00
15-Apr-00
15-Apr-00
15-Apr-00
16-Apr-00
16-Apr-00
16-Apr-00
16-Apr-00
17-Apr-00
17-Apr-00
17-Apr-00
17-Apr-00
18-Apr-00
18-Apr-00
18-Apr-00
18-Apr-00
19-Apr-00
19-Apr-00
19-Apr-00
19-Apr-00
20-Apr-00
20-Apr-00
20-Apr-00
20-Apr-00
Date
Depth of Surface Water (in.)
23
USMC-7
Surface Gauge
-4
-2
0
2
4
6
8
10
12
14
16
08-Apr-00
14-Apr-00
21-Apr-00
28-Apr-00
05-May-00
12-May-00
19-May-00
26-May-00
02-Jun-00
08-Jun-00
15-Jun-00
22-Jun-00
29-Jun-00
06-Jul-00
13-Jul-00
20-Jul-00
27-Jul-00
02-Aug-00
09-Aug-00
16-Aug-00
23-Aug-00
30-Aug-00
06-Sep-00
13-Sep-00
20-Sep-00
26-Sep-00
03-Oct-00
03-Oct-00
09-Oct-00
16-Oct-00
23-Oct-00
30-Oct-00
Date
Surface Water Depth (in.)
gauge
malfunction
24
USMC-7
Surface Gauge
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
14-Apr-00
14-Apr-00
14-Apr-00
14-Apr-00
15-Apr-00
15-Apr-00
15-Apr-00
15-Apr-00
16-Apr-00
16-Apr-00
16-Apr-00
16-Apr-00
17-Apr-00
17-Apr-00
17-Apr-00
17-Apr-00
18-Apr-00
18-Apr-00
18-Apr-00
18-Apr-00
19-Apr-00
19-Apr-00
19-Apr-00
19-Apr-00
20-Apr-00
20-Apr-00
20-Apr-00
20-Apr-00
Date
Depth of Surface Water (in.)
gauge malfunciton
25
USMC-8
Surface Gauge
0
5
10
15
20
25
30
35
08-Apr-00
14-Apr-00
21-Apr-00
28-Apr-00
05-May-00
12-May-00
19-May-00
26-May-00
02-Jun-00
08-Jun-00
15-Jun-00
22-Jun-00
29-Jun-00
06-Jul-00
13-Jul-00
20-Jul-00
27-Jul-00
02-Aug-00
09-Aug-00
16-Aug-00
23-Aug-00
30-Aug-00
06-Sep-00
13-Sep-00
20-Sep-00
26-Sep-00
03-Oct-00
03-Oct-00
09-Oct-00
16-Oct-00
23-Oct-00
30-Oct-00
Date
Suface Water Depth (in.)
26
USMC-8
Surface Gauge
0
5
10
15
20
25
30
14-Apr-00
14-Apr-00
14-Apr-00
14-Apr-00
15-Apr-00
15-Apr-00
15-Apr-00
15-Apr-00
16-Apr-00
16-Apr-00
16-Apr-00
16-Apr-00
17-Apr-00
17-Apr-00
17-Apr-00
17-Apr-00
18-Apr-00
18-Apr-00
18-Apr-00
18-Apr-00
19-Apr-00
19-Apr-00
19-Apr-00
19-Apr-00
20-Apr-00
20-Apr-00
20-Apr-00
20-Apr-00
Date
Depth of Surface Water (in.)
27
APPENDIX B
SITE PHOTOS
USMC
28
Photo 1 Photo 2
Photo 3 Photo 4
Photo 5 Photo 6
USMC
29
Photo 7
30
APPENDIX C
VEGETATION PLANTING PLAN
31