Annual report for ... Mildred Woods mitigation site, Edgecombe County, project no. 6.09902T, TIP no. R-2111/R-2112A

              ANNUAL REPORT FOR 2002
Mildred Woods Mitigation Site
Edgecombe County
Project No. 6.09902T
TIP No. R-2111/R-2112A
Office of Natural Environment & Roadside Environmental Unit
North Carolina Department of Transportation
December 2002/March 2003 (Revised)
TABLE OF CONTENTS
SUMMARY......................................................................................................................1
1.0 INTRODUCTION ..................................................................................................2
1.1 PROJECT DESCRIPTION.........................................................................2
1.2 PURPOSE..................................................................................................2
1.3 PROJECT HISTORY .................................................................................3
1.4 DEBIT LEDGER.........................................................................................3
2.0 HYDROLOGY.......................................................................................................7
2.1 SUCCESS CRITERIA ................................................................................7
2.2 HYDROLOGIC DESCRIPTION..................................................................8
2.3 RESULTS OF HYDROLOGIC MONITORING .........................................10
2.3.1 Site Data........................................................................................10
2.3.2 Climatic Data .................................................................................15
2.4 CONCLUSIONS.......................................................................................15
3.0 VEGETATION ....................................................................................................18
3.1 SUCCESS CRITERIA ..............................................................................18
3.2 DESCRIPTION OF PLANTED AREAS....................................................18
3.3 RESULTS OF VEGETATION MONITORING ..........................................21
3.4 CONCLUSIONS.......................................................................................21
4.0 OVERALL CONCLUSIONS/RECOMMENDATIONS.........................................22
LIST OF FIGURES
Figure 1. Site Location Map ..................................................................................................4
Figure 2. Mildred Woods Delineation Map...........................................................................6
Figure 3. Hydrologic Monitoring Gauge Location Map..........................................................9
Figure 4. Hydrologic Monitoring Results 2002 ....................................................................16
Figure 5. Mildred Woods Mitigation Site 30-70 Percentile Graph, Tarboro, NC .................17
LIST OF TABLES
Table 1. Mildred Woods Mitigation Site Debit Ledger..........................................................5
Table 2. NCDOT Delineation Results ..................................................................................5
Table 3. Individual Gauge Success Criteria.........................................................................7
Table 4. Gauge Locations (Sections 1-12) ..........................................................................8
Table 5. Hydrologic Monitoring Results – Northwest Corner.............................................10
Table 6. Hydrologic Monitoring Results – Northern Area ..................................................10
Table 7. Hydrologic Monitoring Results – Center of Mildred Woods .................................11
Table 8. Hydrologic Monitoring Results – Eastern Area ....................................................11
Table 9. Hydrologic Monitoring Results – Northeast Corner .............................................12
Table 10. Hydrologic Monitoring Results – East of Borrow Pit 1 .........................................12
Table 11. Hydrologic Monitoring Results – Southeast of Borrow Pit 1 ................................13
Table 12. Hydrologic Monitoring Results – West of Borrow Pit 2 ........................................13
Table 13. Hydrologic Monitoring Results – Lower Eastern Area .........................................14
Table 14. Hydrologic Monitoring Results – South of Borrow Pit 1 .......................................14
Table 15. Hydrologic Monitoring Results – Lower Northwest Corner ..................................14
Table 16. Hydrologic Monitoring Results – Middle Northern Area.......................................15
Table 17. Vegetation Monitoring Statistics, by plot..............................................................21
APPENDICES
APPENDIX A DEPTH TO GROUNDWATER CHARTS
APPENDIX B SITE PHOTOS ANDPHOTO AND PLOT LOCATIONS MAP
APPENDIX C HYDROLOGIC MODIFICATION AGENCY NOTIFICATION LETTER
1
SUMMARY
The following report summarizes the monitoring activities that have occurred in the past
year at the Mildred Woods Mitigation Site. Designed as mitigation for impacts
associated with new construction on US 64 in Edgecombe County, the site
encompasses 593 acres, with plant communities reestablished on 372 acres. This site
was originally constructed in 1995 and planted between January and February 1996.
Due to issues with flooding on an adjacent property, and the structural integrity of a
culvert on US 64, NCDOT requested and received a modification approval for the
mitigation site. The initial plan called for a concrete riser that would control water
elevations adjacent to the borrow pit. After further review of the borrow pit area, it was
decided instead to armor the existing outlet ditch for stabilization and not to construct
the concrete riser (See Appendix C). It was determined that the current outlet elevation
of the pond was not adversely affecting the upstream culvert, and this would maintain
the existing site hydrology. This work was completed in mid-June 2002 and did not
change the overall site hydrology. Thus monitoring continued as normal in 2002;
hydrologic and vegetation monitoring have been conducted for a total of seven years.
A total of 76 groundwater monitoring gauges and two rain gauges are used to monitor
the site’s groundwater levels and rainfall amounts, respectively. The success criteria
for these gauges vary dependent upon location; gauges that are expected not to meet
jurisdictional success are in place in order to verify wetland areas. Hydrologic
monitoring indicated that of the 76 gauges at the site, 53 gauges either met or exceeded
their respective hydrologic expectations. Upon reviewing previous data, it can be seen
that gauges meeting their expected hydrology in years past are continuing to meet their
expected hydrology.
Of the 593 acres of this site, approximately 372 involved tree planting. There were 20
plots established throughout the planting areas, encompassing all plant communities.
The 2002 vegetation monitoring of the planted area revealed an average density of 513
trees per acre, which is well above the 320 trees per acre required by the minimum
success criteria.
In summer 2002, NCDOT performed a delineation of the Mildred Woods site. Gauge
data from previous years was initially used to determine areas of the site that were wet
and dry. Based on maps developed from this gauge data, these lines denoting wet
areas were field-verified using hydric soil indicators. NCDOT then used this delineation
map to perform tree counts of nuisance species (red maple, sweet gum, and pine)
within the wet areas of the site. The new delineation map is provided within this report.
NCDOT will develop a proposal for the nuisance vegetation per discussions at field
meetings with resource agency personnel. Once agency concurrence is obtained, the
proposal will be implemented in 2003 in order to finalize/ close this site.
2
1.0 INTRODUCTION
1.1 Project Description
As part of a mandate to improve the North Carolina Intrastate System, US 64 was
extended on new location from the US 64/258/NC 44 Interchange south of Tarboro to a
location west of Everetts at the US 64/SR 1405. The Mildred Woods Mitigation Site was
created to compensate for unavoidable wetland losses incurred during roadway
construction.
Located in Edgecombe County, the site is approximately three miles east of Tarboro. It
encompasses approximately 593 acres and is situated near the Tar River, immediately
adjacent to the newly constructed US 64 (Figure 1). Wetland plant communities will be
reestablished on approximately 372 of the 593 acres. Plant communities include
swamp forest (37 acres), Atlantic white cedar (2 acres), wet hardwood forest (214
acres), oak-hickory forest (108 acres), and long leaf pine-oak/hickory forest (11 acres).
The site was constructed in 1995, and it was first monitored for both hydrology and
vegetation in 1996. Work to stabilize the entrance of an outlet ditch on the south side of
the existing borrow lake was completed during the 2002 growing season. As the work
did not interfere with the overall site hydrology, monitoring continued in 2002 for a
seventh year.
1.2 Purpose
In order to demonstrate successful mitigation, vegetative and hydrologic monitoring will
be conducted for a minimum of three years. The following report details the results of
hydrologic and vegetative monitoring during 2002, the seventh year of monitoring.
Included in this report is the following: analyses of site data and local climate conditions
during the growing season, site photographs, and maps of both hydrologic and
vegetation monitoring areas.
3
1.3 Project History
Summer 1995 Construction - Ditches plugged and filled
Sept.-Oct. 1995 KG Shearing/Piling
Jan.-Feb. 1996 Tree Planting
February 1996 Monitoring Gauges Installed
March- November 1996 Hydrologic Monitoring (1 yr.)
October 1996 Vegetation Monitoring (1 yr.)
March 1997 Additional Monitoring Gauges Installed
March- November 1997 Hydrologic Monitoring (2 yr.)
August 1997 Vegetation Monitoring (2 yr.)
March- November 1998 Hydrologic Monitoring (3 yr.)
September 1998 Vegetation Monitoring (3 yr.)
February 1999 Additional gauges installed
March- November 1999 Hydrologic Monitoring (4 yr.)
October 1999 Vegetation Monitoring (4 yr.)
March- November 2000 Hydrologic Monitoring (5 yr.)
October 2000 Vegetation Monitoring (5 yr.)
March 2001 North side ditch flow diverted to SR 1523
March- November 2001 Hydrologic Monitoring (6 yr.)
October 2001 Vegetation Monitoring (6 yr.)
March- November 2002 Hydrologic Monitoring (7 yr.)
June 2002 Stabilization of Borrow Pit Outlet
Summer 2002 Site Delineation
August 2002 Vegetation Monitoring (7 yr.)
1.4 Debit Ledger
Table 1 is the current debit ledger for the Mildred Woods Site. The new delineation map
(Figure 2) was used to update the acreage of wetlands delineated, uplands, and
wetland acreage debited for roadway projects. Table 2 summarizes the total acreage of
the dry areas; these are not included in the debited area of the site.
4
Figure 1. Site Location Map
5
Table 1. Mildred Woods Mitigation Site Debit Ledger
Mitigation Plan TIP Debit
Site Habitat Acres
at Start
Acres
Remaining
Percent
Remaining
R-509GB,
R-2111&
R-2112A
R-2112B Alterations* U-2218*† U-2720*† B-2980
BLH Restoration 369.00 129.00 34.96 217.00 23.00 23.50 21.41
SPH Restoration 26.00 23.00 88.46 6.00 3.00
Preservation 23.00 8.00 34.78 15.00
Upland Mgmnt 200.00 N/A --
Total** 418.00 160.00 38.28
SPH: Swamp Hardwood BLH: Bottomland Hardwood *: hydrologic modifications under review by US Army Corps of Engineers
†: Proposed **: Excludes management habitat
Table 2. NCDOT Delineation Results- Mildred Woods
Section
(Corresponding to
Placed Gauges)
New Upland Acreage
2 65.2
2 0.88
5 2.0
5 17.6
3,10 106.6
4 7.2
4 5.4
8 9.0
Total Upland Acreage 213.9
Total Wet Acreage (593 Ac Total-
Upland)
379.1
6
Figure 2. Mildred Woods Delineation Map (sections shown to be dry noted in blue, with acreage)
7
2.0 HYDROLOGY
2.1 Success Criteria
Hydrological success criteria include saturation or inundation (within 12” of surface) for
at least 12.5% of the growing season at lower landscape positions during average
climatic conditions. Upper landscape areas of the wetland restoration areas may exhibit
surface saturation/inundation for between 5% and 12.5% of the growing season based
on gauge data. Several monitoring gauges were placed at locations where saturation is
expected to be less than 5% of the growing season, in order to aid in the delineation of
true wetland area. Table 3 summarizes the wetland criteria expected for each
monitoring gauge by showing which gauges in each section are expected to meet which
criteria.
The growing season in Edgecombe County begins March 21 and ends November 10.
These dates correspond to a 50% probability that air temperatures will drop to 28o F or
lower after March 21 and before November 10.1 Thus, the growing season is 233 days;
optimum wetland hydrology requires 12.5%, or a consecutive 29 days. However, the
site must also experience average climatic conditions for the data to be valid.
Table 3. Individual Gauge Success Criteria
Expected % of the Growing Season with Saturated Conditions
Table Number < 5% 5 - 12.5% > 12.5%
Table 5 6,7 1 – 5, 15C – 18C
Table 6 10 8, 9
Table 7 19C,21C 11 – 15
Table 8 16 17,29C 18, 20C, 26C – 28C
Table 9 27 26,1C,2C 19 - 25,3C – 5C,7C,8C
Table 10 28, 29
Table 11 30,31,32,33, 23C 22C
Table 12 34,35,36,37,38,39,31C, 32C
Table 13 30C 40, 25C
Table 14 41 24C
Table 15 42, 11C-14C, 33C
Table 16 6C, 9C 43, 10C
1 Soil Conservation Service, Soil Survey of Edgecombe County, North Carolina, 1979.
8
2.2 Hydrologic Description
Seventy-six monitoring gauges and two rain gauges were installed on site in between
1996 and 2000 (Figure 3). The automatic monitoring gauges and rain gauges record
depth to groundwater and rainfall, respectively. Daily readings of groundwater levels
and rainfall totals are taken throughout the growing season.
Because Mildred Woods is a large site, it is divided into sections according to gauge
locations. Table 4 lists the location of each table and the gauges contained in each
section. Borrow Pit 1 is located on the west side of the site. Borrow Pit 2 is located on
the east side of the site.
Appendix A contains a plot of the groundwater depth for each monitoring gauge during
the 2002 growing season. Precipitation events, recorded by the onsite rain gauges, are
included on each graph as bars. These monitoring gauge graphs are designed to show
the reaction of the groundwater level to specific rainfall events. If the gauge shows
saturation for 5% or greater of the growing season, the maximum number of
consecutive days is noted on each graph.
Table 4. Gauge Locations
Table
Number Location # of
Gauges Gauge Numbers
5 Northwest Corner 11 MW 1 – 7, MW 15C-18C
6 Northern Area 3 MW 8 –10
7 Center of Mildred Woods 7 MW 11 – 15, MW 19C & 21C
8 Eastern Area 8 MW 16 – 18, MW 20C, 26C-29C
9 Northeast Corner 16 MW 19 – 27, MW 1C-5C, 7C, 8C
10 East of Borrow Pit 1 2 MW 28 – 29
11 Southeast of Borrow Pit 1 6 MW 30 – 33, MW 22C & 23C
12 West of Borrow Pit 2 8 MW 34 – 39, MW 31C & 32C
13 Lower Eastern Area 3 MW 40, MW 25C & 30C
14 South of Borrow Pit 1 2 MW 41, MW 24C
15 Lower Northwest Corner 6 MW 42, MW 11C-14C, 33C
16 Middle Northern Area 4 MW 43, MW 6C, 9C, 10C
9
Figure 3. Hydrologic Monitoring Gauge Location Map (Delineated areas shown in blue)
10
2.3 Results of Hydrologic Monitoring
2.3.1 Site Data
The total 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 233-day growing season. The results are presented in Tables 5 to 16.
Note that specific gauge problems listed below tables are only for those gauges that did
not meet their expected hydrology.
Table 5. Hydrologic Monitoring Results – Northwest Corner
Gauge Expected % <5% 5 - 8% 8 -
12.5% > 12.5% Actual %
MW-1 12.5 5.3
MW-2 12.5 13.8
MW-3 12.5 13.8
MW-4 12.5 16.7
MW-5 12.5 12.2
MW-6 0 5 1.2
MW-7 0 5 0.0
MW-15C 12.5 16.7
MW-16C 12.5 16.7
MW-17C 12.5 16.7
MW-18C 12.5 16.7
Nine of the eleven gauges in the northwest corner met their respective expected
hydrology.
-Gauge 1 did not record data from Aug 1 to Sept 12, due to a malfunction.
Table 6. Hydrologic Monitoring Results – Northern Area
Gauge Expected % <5% 5 - 8% 8 -
12.5% > 12.5% Actual %
MW-8 12.5 36.9
MW-9 12.5 12.2
MW-10 0 5 2.9
Two of the three gauges in the northern area met their respective expected hydrology.
11
Table 7. Hydrologic Monitoring Results – Center of Mildred Woods
Gauge Expected % <5% 5 - 8% 8 -
12.5% > 12.5% Actual %
MW-11 12.5 2.0
MW-12 12.5 1.2
MW-13 12.5 12.2
MW-14 12.5 0.4
MW-15 12.5 2.4
MW-19C 5 12.5 16.7
MW-21C 12.5 4.1
Only one of the seven gauges in the center section met the expected hydrology.
-Gauge 12 did not record data from Jan 1 to Feb 6, due to dead batteries.
-Gauge 14 went down from Aug 2 to Oct 16, when it was replaced.
-Gauge 15 did not record valid data from Jan 1 to Feb 25, due to a malfunction.
Table 8. Hydrologic Monitoring Results – Eastern Area
Gauge Expected % <5% 5 - 8% 8 -
12.5% > 12.5% Actual %
MW-16 0 5 0.4
MW-17 5 12.5 12.2
MW-18 12.5 15.0
MW-20C 12.5 17.1
MW-26C 12.5 16.7
MW-27C 12.5 13.0
MW-28C 12.5 16.7
MW-29C 5 12.5 4.1
Seven of the eight gauges in the eastern area met or exceeded their respective
expected hydrology.
-Gauge 29C stopped recording data from Jan 1 to Feb 25, and again from Aug 2 to
Sept 12, when it was replaced.
12
Table 9. Hydrologic Monitoring Results – Northeast Corner
Gauge Expected % <5% 5 - 8% 8 -
12.5% > 12.5% Actual %
MW-19 12.5 16.3
MW-20 12.5 17.1
MW-21 12.5 24.8
MW-22 12.5 13.0
MW-23 12.5 12.1
MW-24 12.5 16.3
MW-25 12.5 13.8
MW-26 5 12.5 16.7
MW-27 0 5 8.5
MW-1C 5 12.5 16.7
MW-2C 5 12.5 .4
MW-3C 12.5 17.1
MW-4C 12.5 16.7
MW-5C 12.5 16.7
MW-7C 12.5 16.7
MW-8C 12.5 27.6
Fifteen of the sixteen gauges in the northeast corner met or exceeded their respective
hydrologic requirement.
Table 10. Hydrologic Monitoring Results – East of Borrow Pit 1
Gauge Expected % <5% 5 - 8% 8 -
12.5% > 12.5% Actual %
MW-28 12.5 12.2
MW-29 12.5 8.5
None of the two gauges east of Borrow Pit 1 met expected hydrology.
-Gauge 29 did not record data from Jan 1- Feb 25, due to a malfunction.
13
Table 11. Hydrologic Monitoring Results – Southeast of Borrow Pit 1
Gauge Expected % <5% 5 - 8% 8 -
12.5% > 12.5% Actual %
MW-30 5 12.5 2.4
MW-31 5 12.5 8.5
MW-32 5 12.5 12.2
MW-33 5 12.5 12.2
MW-22C 12.5 16.7
MW-23C 12.5 14.6
Five of the six gauges southeast of Borrow Pit 1 met or exceeded expected hydrology.
Table 12. Hydrologic Monitoring Results – West of Borrow Pit 2
Gauge Expected % <5% 5 - 8% 8 -
12.5% > 12.5% Actual %
MW-34 5 12.5 0.0
MW-35 5 12.5 .81
MW-36 5 12.5 1.2
MW-37 5 12.5 2.8
MW-38 5 12.5 8.5
MW-39 5 12.5 8.5
MW-31C 12.5 13.0
MW-32C 5 12.5 6.5
Four of the eight gauges west of Borrow Pit 2 met the expected hydrology for the area.
14
Table 13. Hydrologic Monitoring Results – Lower Eastern Area
Gauge Expected % <5% 5 - 8% 8 -
12.5% > 12.5% Actual %
MW-40 12.5 12.2
MW-25C 12.5 16.7
MW-30C 5 12.5 13.0
Two of the three gauges in the lower eastern area met expected hydrology.
Table 14. Hydrologic Monitoring Results – South of Borrow Pit 1
Gauge Expected % <5% 5 - 8% 8 - 12.5% > 12.5% Actual %
MW-41 0 5 12.6
MW-24C 5 12.5 3.7
One of the two gauges south of Borrow Pit 1 greatly exceeded its expected hydrology,
which was to show saturation for less than 5% of the growing season.
Table 15. Hydrologic Monitoring Results – Lower Northwest Corner
Gauge Expected % <5% 5 - 8% 8 - 12.5% > 12.5% Actual %
MW-42 12.5 8.5
MW-11C 12.5 16.7
MW-12C 12.5 16.7
MW-13C 12.5 16.7
MW-14C 12.5 6.5
MW-33C 12.5 16.7
Four of the six gauges in the lower northwest corner met or exceeded the expected
hydrology for the area.
-Gauge 14C did not record data from Feb 22 to May 21, when it was replaced.
15
Table 16. Hydrologic Monitoring Results – Middle Northern Area
Gauge Expected % <5% 5 - 8% 8 - 12.5% > 12.5% Actual %
MW-43 12.5 15.0
MW-6C 5 12.5 13.0
MW-9C 5 12.5 16.7
MW-10C 12.5 9.4
Three of the four gauges in the middle northern area met or exceeded the expected
hydrology.
-Gauge 10C did not record data from Aug 9 to Sept 12, due to battery failure
Figure 4 is a graphical representation of the 2002 hydrologic results.
2.3.2 Climatic Data
Figure 5 is a comparison of 2002 monthly rainfall to historical precipitation for the area.
The two lines represent the 30th and 70th percentiles of monthly precipitation for
Tarboro, NC, located in Edgecombe County. The NC State Climate Office provided
both the historical and the current precipitation totals. The bars are monthly rainfall
totals for portions of 2001 and 2002, collected since the publication of the 2001 annual
report. Because data from November and December 2002 were not available at the
time this report was published, the 2002 rainfall data encompasses precipitation totals
through October.
Overall, the Tarboro area had an average climatic year in terms of rainfall totals. Only
four of the twelve months yielded below average rainfall amounts. The site received
below average totals in November (2001), December (2001), February, and May, while
it received above average precipitation in January and July.
2.4 Conclusions
Of the 76 gauges currently on the site, 53 gauges either met or exceeded their
respective hydrologic expectations during a year with average rainfall. Most of the
gauges that did not meet the hydrologic expectations for the 2002 growing season are
either located adjacent to the borrow pits or within the center area of the site.
16
Figure 4. Hydrologic Monitoring Results 2002
17
18
Figure 5: Mildred Woods 30-70 Percentile Graph Tarboro, NC
0
1
2
3
4
5
6
7
Nov 01' Dec 01' Jan 02' Feb 02' Mar 02' Apr 02' May 02' Jun 02' Jul 02' Aug 02' Sep 02' Oct 02' Nov 02' Dec 02'
Month
2002 Rainfall 2001 Rainfall 30th Percentile 70th Percentile
Average Rainfall
* *
30 th Percentile
70th Percentile
19
3.0 VEGETATION
3.1 Success Criteria
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. Minimum of 6
hardwood species with no more than 20% of any one species and up to 10% of site
species may be comprised of softwood species.
3.2 Description of Planted Areas
The following plant communities were planted in the Wetland Restoration Area:
Zone 1: Swamp Forest (approximately 37 acres)
Nyssa aquatica, Water Tupelo
Taxodium distichum, Bald cypress
Fraxinus pennsylvanica, Green Ash
Quercus laurifolia, Laurel Oak
Nyssa sylvatica var. biflora, Swamp Tupelo
Carya aquatica, Water Hickory
Platanus occidentalis, American Sycamore
Quercus lyrata, Overcup Oak
Zone 2: Wet Hardwood Forest (approximately 214 acres)
Fraxinus pennsylvanica, Green Ash
Quercus falcata var. pagodaefolia, Cherrybark Oak
Quercus michauxii, Swamp Chestnut Oak
Quercus phellos, Willow Oak
Quercus nigra, Water Oak
Liriodendron tulipfera, Tulip Poplar
Quercus laurifolia, Laurel Oak
Ulmus americana, American Elm
Quercus falcata, Swamp Red Oak
Zone 3: Dry-Mesic Oak/Hickory Forest (approx. 108 acres)
Quercus alba, White Oak
Quercus falcata, Swamp Red Oak
Carya tomentosa, Mockernut Hickory
Carya glabra, Pignut Hickory
Quercus stellata, Post Oak
Quercus nigra, Water Oak
20
Zone 4: Long-Leaf Pine-Oak/Hickory (approximately 11 acres)
Pinus palustris, Longleaf Pine
Quercus marilandica, Blackjack Oak
Quercus velutina, Black Oak
Quercus stellata, Post Oak
Carya tomentosa, Mockernut Hickory
Carya glabra, Pignut Hickory
Zone 5: Atlantic White Cedar Test Area (approximately 2 acres)
Chamaecyparis thyoides, American White Cedar
21
3.3 Results of Vegetation Monitoring
Table 17. Vegetation Monitoring Statistics, by plot
22
2 5 4 1 10 27
3 1 2 9 5 4 1 1 23 23
4 3 12 4 1 20 27
5 2 1 6 12 3 1 2 3 30 31
6 4 11 7 6 28 31
7 1 4 3 1 5 14 22
8 8 12 3 1 4 2828
9 2 4 16 3 25 29
10 1 1 4 1 11 11 29 29
16 10 4 1 2 17 22
17 1 1 9 13 2 1 27 28
18 1 2 7 1 11 21
20 2 3 2 7 21
21 1 3 1 5 2 12 21
23
Site Notes: Other species noted: sweetgum, trumpet creeper, broomsedge, Juncus sp.,
ragweed, Aster sp., volunteer tulip poplar, volunteer hickory, fennel, goldenrod, pine,
foxtail, wax myrtle, elm, Carex sp., giant cane, woolgrass, devil’s walking stick, briars,
magnolia, pokeweed, winged sumac, grapevine, smartweed, sicklepod, Pluchea sp.,
black willow, and switchgrass. Plots 1, 11-15, and 28 have not been monitored
because the plot locations are in existing woods. Plot 20 was monitored again this year.
Few trees were found due to heavy competition. Plot 19 was not monitored because of
heavy competition. It was noted that certain areas within the site consisted of heavy
natural regeneration of sweet gum, pine, and red maple. Overall, the mitigation site is
performing well in terms of vegetation survival.
3.4 Conclusions
Of the 593 acres of this site, approximately 372 involved tree planting. There were 20
plots established throughout the planting areas, encompassing all plant communities.
The 2002 vegetation monitoring of the planted area revealed an average density of 513
trees per acre, which is well above the 320 trees per acre required by the minimum
success criteria.
NCDOT has met with Ron Myers, a Hardwood Specialist with the North Carolina Forest
Service on the sweetgum and pine issue. Sample plots were set and tree populations
were counted throughout the site. The plots were 0.02 acre in size and were set at
approximately 132 feet apart. Planted species, pine and sweetgum were the only trees
counted in the samples. Only species three feet tall or higher were counted. It was
noted from the sample plots that the outer perimeter of the site consisted of the most
sweetgum and pine vegetation.
NCDOT proposes to discontinue vegetation monitoring at the Mildred Woods Mitigation
Site, as the planted species have continued to show excellent survival rates.
24
4.0 OVERALL CONCLUSIONS/RECOMMENDATIONS
Monitoring of the Mildred Woods Mitigation Site yielded the following:
Hydrologic monitoring indicated that of the 76 gauges currently on site, 53
gauges either met or exceeded their respective hydrologic expectations.
The majority of the gauges not meeting their expected success criteria are
located adjacent to either of the borrow pits or within the center area.
It can be seen from previous data that gauges meeting their expected hydrology
in years past are continuing to meet their expected hydrology.
The vegetation monitoring of the planted area revealed an average density of
513 trees per acre, which is well above the 320 trees per acre required by the
minimum success criteria.
Based on the 2002 monitoring results, NCDOT intends:
To develop a proposal regarding nuisance vegetation per discussions with
resource agency personnel.
Once agency concurrence is obtained, the proposal will be implemented in 2003
in order to facilitate the closing of the site.
APPENDIX A
DEPTH TO GROUNDWATER CHARTS
APPENDIX B
SITE PHOTOS AND
PHOTO AND PLOT LOCATIONS MAP
MILDRED WOODS
2002
Photo 1 Photo 2
Photo 3 Photo 4
Photo 5 Photo 6
MILDRED WOODS
2002
Photo 7 Photo 8
Photo 9 Photo 10
Photo 11
MILDRED WOODS
2002
2002
APPENDIX C
HYDROLOGIC MODIFICATION AGENCY NOTIFICATION
LETTER, AUGUST 23, 2002
2002
STATE OF NORTH CAROLINA
DEPARTMENT OF TRANSPORTATION
MICHAEL F. EASLEY 1501 MAIL SERVICE CENTER, RALEIGH, N.C. 27699-1501 LYNDO TIPPETT
GOVERNOR SECRETARY
August 23, 2002
Raleigh Regulatory Field Office
U.S. Army Corps of Engineers
6508 Falls of Neuse Road
Suite 120
Raleigh, North Carolina 27615
Attention: Mr. Eric Alsmeyer
Subject: Remediation Activities at Mildred Woods Mitigation Site in Edgecombe County,
State Project No. 6.099008T, TIP No. R-2111/R-2112A. COE Action ID
200220237.
The North Carolina Department of Transportation (NCDOT) proposed to complete remediation
efforts at the Mildred Woods Mitigation Site in Edgecombe County utilizing Nationwide Permit
27, which was issued on December 10, 2001. The final remediation work, as described in the
NW-27 permit, involved the installation of a concrete flashboard riser in the outlet ditch on the
south side of the borrow pond.
Based on the initial survey conducted June 1997, the original plan proposed to install a concrete
flashboard riser to maintain a maximum water surface elevation of 43 feet MSL, on the Mildred
Woods Mitigation Site. In February 2002, NCDOT conducted a new survey, which concluded
an elevation of 44.16. At that time NCDOT began to question the need for such a structure in
the outlet ditch of the borrow pond. On May 7, 2002, NCDOT and the regulatory agencies met
on-site to review the proposal. During that visit, it was concluded that some bank stabilization
was needed at the entrance of the outlet ditch, however the concrete flashboard riser was not
necessary. Also, all were in agreement that the current water surface elevation that has been
maintained in the borrow pond had caused no noticeable problems with the existing pond nor
with the interchange at SR 1523 (Shiloh Farm Road).
Instead, the Department proposed to stabilize the entrance of the outlet ditch using class-B rip-rap
and filter fabric. Because of the minimal length of rip-rap, this activity was covered under
Nationwide Permit 13 (Bank Stabilization) and requires that the Department notify the U.S.
Army Corps of the Engineers upon successful completion of the activity. The NCDOT
2002
Edgecombe County Maintenance Forces completed this work on mid June 2002. (See
attachment photo documentation)
If you have any questions or need any additional information, please contact Randy Griffin at
(919) 733-7844 Ext. 294
Sincerely,
V. Charles Bruton, Ph.D.
Manager Office of Natural Environment
Project Development and Environmental
Analysis Branch
Cc: file
Mr. John Hennessy, NCDWQ
Mr. Howard Hall, USFWS
Mr. David Cox, NCWRC
Mr. Jim Trogdon, PE, Division Engineer
Mr. Bobby Lewis, PE, Highway Maintenance Engineer
2002
Northeast at entrance to outlet.
Southwest across Borrow Pond towards outlet ditch.