ANNUAL REPORT FOR 2004
White Oak Creek
Johnston County
Project No. 6.408014T
TIP No. R-2000 WM
Prepared By:
Office of Natural Environment & Roadside Environmental Unit
North Carolina Department of Transportation
December 2004
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 HYDROLOGIC DESCRIPTION ................................................................. 4
2.3 RESULTS OF HYDROLOGIC MONITORING........................................... 6
2.3.1 Site Data ......................................................................................... 6
2.3.2 Climatic Data................................................................................. 10
2.4 CONCLUSIONS ...................................................................................... 10
3.0 VEGETATION: WHITE OAK CREEK MITIGATION SITE ................................. 12
3.1 SUCCESS CRITERIA.............................................................................. 12
3.2 DESCRIPTION OF SPECIES.................................................................. 12
3.3 RESULTS OF VEGETATION MONITORING.......................................... 14
3.4 CONCLUSIONS ...................................................................................... 14
4.0 OVERALL CONCLUSIONS/RECOMMENDATIONS.......................................... 15
LIST OF TABLES
Table 1. 2004 White Oak Creek Hydrologic Monitoring Results .............................. 7
Table 2. Vegetation Monitoring Statistics............................................................... 14
LIST OF FIGURES
Figure 1. Site Location Map...................................................................................... 3
Figure 2. Monitoring Gauge Location Map................................................................ 5
Figure 3 . Monitoring Gauge Hydrologic Results........................................................ 9
Figure 4. White Oak Creek 30-70 Graph ................................................................ 11
APPENDICES
APPENDIX A - GAUGE DATA GRAPHS
APPENDIX B - SITE PHOTOS & PLANTING PLAN
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SUMMARY
The following report summarizes the monitoring activities that have occurred in the past
year on the White Oak Creek Mitigation Site. Site construction began in January 2002
and was completed in March 2002. The site was planted in late March 2002 and
replanted in December 2002. The 2004-year represents the second year of vegetation
monitoring. Hydrology monitoring in 2004 represents the third year of monitoring at the
site. The site must demonstrate both hydrologic and vegetation success for a minimum
of five consecutive years or until the site is deemed successful. The site is monitored
with thirty-eight groundwater monitoring gauges and eight vegetation plots.
The 2004-year represents the third year for hydrology monitoring. Overall, twenty-six of
the thirty-six (non-reference) monitoring gauges indicate saturation within 12” of the
surface for greater than 12.5% of the growing season. The two reference gauges, REF-
37 and REF-38, also met the saturation criteria. Ten of the thirty-six gauges did not
meet the jurisdictional success criteria for the 2004-monitoring year.
The 2004 vegetation monitoring of the site revealed an average density of 375 trees per
acre. This average is well above the minimum success criteria of 320 trees per acre.
Per letter from the Ecosystem Enhancement Program to NCDOT dated August 25,
2004, the EEP has accepted the transfer of all off-site mitigation projects. The EEP will
be responsible for fulfilling the remaining monitoring requirements and future
remediation for this project.
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1.0 INTRODUCTION
1.1 PROJECT DESCRIPTION
The White Oak Creek Site is located adjacent to the west bank of White Oak Creek,
immediately south of Winston Road (SR 1550) and north of Austin Pond, approximately
2.5 miles west of Clayton, NC in Johnston County.
The site, totaling 50.69 acres in size, was mostly in open pastureland that was used to
support horses in the past. Currently, the site has been returned to its natural condition.
Construction started in January 2002 and was completed in March 2002. Planting was
completed in March 2002.
1.2 PURPOSE
In order to demonstrate successful mitigation, hydrologic and vegetative monitoring
must be conducted for a minimum of five consecutive years. Success criteria are based
on federal guidelines for wetland mitigation. These guidelines stipulate criteria for both
hydrologic conditions and vegetation survival. The following report details the results of
hydrologic and vegetative monitoring during the 2004-growing season at the White Oak
Creek Mitigation Site.
Activities in 2004 reflect the third year of hydrology monitoring and the second year for
vegetation monitoring, following the restoration efforts. Included in this report are
analyses of both hydrologic and vegetative monitoring results, as well as local climate
conditions throughout the growing season, and site photographs.
1.3 PROJECT HISTORY
January 2002- March 2002 Site Construction
March 2002 Site Planted
August 2002 Vegetation Monitoring (1 yr.)
March – November 2002 Hydrologic Monitoring (1 yr.)
December 2002 Site Replanted
June 2003 Vegetation Monitoring (Restart Year 1)
March – November 2003 Hydrologic Monitoring (2 yr.)
June 2004 Vegetation Monitoring (2 yr.)
March – November 2004 Hydrologic Monitoring (3 yr.)
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Figure 1: Vicinity Map
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2.0 HYDROLOGY
2.1 SUCCESS CRITERIA
In accordance with federal guidelines for wetland mitigation, the success criteria for
hydrology states that the area must be inundated or saturated (within 12” of the surface)
by surface or groundwater for at least a consecutive 12.5% of the growing season
during a normal precipitation year. Areas inundated for less than 5% of the growing
season are always classified as non-wetlands.
A site may be found to meet the hydrology performance criteria on the basis of
comparison of monitoring data taken from the site with monitoring data taken from an
established reference site approved by the Corps. The Corps retains the discretion to
find that the hydrology criteria are met if such monitoring data from the mitigation site
and the reference site are similar.
The growing season in Johnston County begins March 26 and ends November 10.
These dates correspond to a 50% probability that temperatures will not drop to 28°F or
lower after March 26 and before November 10.1 The growing season is 229 days;
therefore, optimum hydrology requires 12.5% of this season, or at least 29 consecutive
days. Local climate must also represent average conditions for the area.
2.2 HYDROLOGIC DESCRIPTION
In March of 2002, thirty-eight monitoring gauges were installed across the site (Figure
2). The automatic monitoring gauges record daily readings of groundwater depth. This
represents the third full growing season that the monitoring gauges have been in place.
The White Oak Creek Site was designed to receive hydrologic input from rainfall and
surface water accessing the floodplain. The hydrologic monitoring should show the
reaction of the groundwater level to specific rainfall events.
1 Natural Resources Conservation Service, Soil Survey of Wake County, North Carolina, p. 79.
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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 well. This number was converted into a
percentage of the 229-day growing season (March 26 – November 10). The results are
presented in Table 1.
Appendix A contains a plot of the groundwater depth for each monitoring well. If the
gauge shows saturation for greater than 12.5% of the growing season, the maximum
number of consecutive days is noted on each graph. The individual precipitation events
are shown on the monitoring well graphs as bars.
Figure 3 provides a graphical representation of the hydrologic results. Gauges
highlighted in blue indicate wetland hydrology for more than 12.5% of the growing
season. Gauges highlighted in red show hydrology between 8% and 12.5% of the
growing season, while those in green indicate hydrology between 5% and 8%. Gauges
highlighted in black indicate no wetland hydrology (less than 5% of the growing season).
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Table 1. 2004 White Oak Creek Hydrologic Monitoring Results
Monitoring
Well <5% 5-8% 8-12.5% >12.5% Actual % Dates Meeting
Success
GW-1* r 1.7
GW-2*+ r 13.5
March 26-April 25
April 27-May 10
Aug 30-Sept 26
GW-3* r 4.8
GW-4+ r 100 March 26-Nov 10
GW-5*+ r 51.7 March 26-May 14
June 15-Oct 11
GW-6 r 11.7
March 26-April 21
Aug 13-Aug 25
Aug 30-Sept 25
GW-7*+ r 13.0
March 26-April 25
April 27-May 10
Aug 30-Sept 26
GW-8* r 9.1 Sept 16-Sep 28
Oct 19-Nov 8
GW-9+ r 39.1 March 26-May 10
GW-10*+ r 29.6 March 26-June 1
June 5-July 16
GW-11*+ r 80.9 April 2-Oct 4
GW-12* r 0.9
GW-13+ r 45.2 March 26-May 28
July 30-Nov 10
GW-14*+ r 23.0 April 2-May 16
Aug 13-Oct 4
GW-15* r 0.4
GW-16*+ r 83.9 March 26-Oct 4
GW-17*+ r 50.4 March 26-July 19
GW-18+ r 45.2 March 26-May 20
May 31-July 26
GW-19 r 3.0
GW-20*+ r 22.6 March 26-May 16
June 5-June 18
GW-21* r 11.4 April 1-April 20
Aug 30-Sept 24
8
Monitoring
Well <5% 5-8% 8-12.5% >12.5% Actual % Dates Meeting
Success
GW-22* r 20.1 March 26-May 10
GW-23*+ r 18.3 April 1-May12
Aug 30-Oct 2
GW-24* r 20.5 March 26-May 11
GW-25*+ r 32.3 March 26-May 17
July 30-Oct 11
GW-26* r 46.3 April 2-July 16
Sept 25-Nov 5
GW-27*+ r 45.0 May 31-June 22
July 30-Nov 10
GW-28*+ r 18.3 April 1-May 12
GW-29*+ r 35.8 March 26-June 15
GW-30* r 1.3
GW-31*+ r 18.3 April 1-May 12
GW-32*+ r 74.3 May 23-Nov 10
GW-33*+ r 49.1 March 26-July 16
GW-34+ r 100.0 March 26-Nov 10
GW-35+ r 44.8 March 26-May 28
July 30-Nov 10
GW-36* r 0
REF-37+ r 100 March 26-Nov 10
REF-38+ r 20.4 March 26-May 11
* Gauge experienced a malfunction during the growing season.
+Gauge met the success criterion during an average rainfall month (February, April,
May, July, and November).
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2.3.2 Climatic Data
Figure 4 represents an evaluation of the local climate in comparison with historical data
in order to determine whether 2004 was “average” in terms of rainfall. The two lines
represent the 30th and 70th percentiles of monthly precipitation for Clayton. The bars
are the monthly rainfall totals for parts of 2003 and 2004. The onsite rain gauge
experienced a gauge malfunction, therefore the rain gauge from the Clayton weather
station was used for the following dates: January 1 - May 4 and July 9 - November 26.
The State Climate Office collected the historical and monthly rainfall data.
For the 2004-year, the month of January, March, and October recorded below average
rainfall. The months of November (03’), December (03’), February, April, May, July, and
November all recorded average rainfall for the site. June, August, and September all
recorded above average rainfall. Overall, 2004 experienced an average rainfall year.
2.4 CONCLUSIONS
Twenty-six of the thirty-six (non-reference) monitoring gauges indicated saturation
within 12” of the surface for greater than 12.5% of the growing season. Three gauges
resulted in saturation between 8% and 12.5% and no gauges showed saturation levels
between 5% and 8%. Seven of the thirty-six gauges had saturation levels less than 5%
of the growing season. Both reference gauges (REF-37 and REF-38) met the
jurisdiction criteria in 2004.
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Figure 4: 30-70 Percentile Graph
White Oak Creek 30-70 Percentile Graph
Clayton, NC
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2
4
6
8
10
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14
Nov 03' Dec 03' Jan 04' Feb 04' Mar 04' Apr 04' May 04' Jun 04' Jul 04' Aug 04' Sep 04' Oct 04' Nov 04' Dec 04'
Month
Precipitation (inches)
2003 Rainfall 2004 Rainfall 30th Percentile 70th Percentile
30th Percentile
70th Percentile
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3.0 VEGETATION: WHITE OAK MITIGATION SITE
(YEAR 2 MONITORING)
3.1 SUCCESS CRITERIA
Success Criteria states that at least 320 stems per acre must survive after the
completion of the third growing season. The required survival criterion will decrease by
10% per year after the third year of vegetation monitoring (i.e., for an expected 290
stems per acre for year 4, and 260 stems per acre for year 5.)
3.2 DESCRIPTION OF SPECIES
The following tree species were planted in the Wetland Areas:
Zone 1: Wetland Restoration Area (10.03 acres)
Quercus lyrata, Overcup Oak
Quercus michauxii, Swamp Chestnut Oak
Quercus phellos, Willow Oak
Quercus nigra, Water Oak
Nyssa sylvatica var. biflora, Swamp Blackgum
Fraxinus pennsylvanica, Green Ash
Cornus amomum, Silky Dogwood
Sambucus canadensis, Elderberry
Cephalanthus occidentalis, Buttonbush
Zone 2: Wetland Enhancement Area (1.58 acres)
Quercus lyrata, Overcup Oak
Quercus michauxii, Swamp Chestnut Oak
Quercus phellos, Willow Oak
Quercus nigra, Water Oak
Nyssa sylvatica var. biflora, Swamp Blackgum
Fraxinus pennsylvanica, Green Ash
Cornus amomum, Silky Dogwood
Sambucus canadensis, Elderberry
Cephalanthus occidentalis, Buttonbush
Zone 3: Wetland Creation Area (6.59 acres)
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Quercus lyrata, Overcup Oak
Quercus michauxii, Swamp Chestnut Oak
Quercus phellos, Willow Oak
Quercus nigra, Water Oak
Nyssa sylvatica var. biflora, Swamp Blackgum
Fraxinus pennsylvanica, Green Ash
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3.3 RESULTS OF VEGETATION MONITIORING
Table 2. Vegetation Monitoring Statistics
Site Notes: Other species noted: ragweed, broomsedge, Scirpus sp., black willow,
Juncus sp., trumpet creeper, briars, fennel, smartweed, cattails, yellow nutsedge,
fescue, arrow arum, lespedeza, and various grasses. Due to heavy competition of
Juncus sp. in plots 2, 3, 6, and 8 the trees were very difficult to find. Plots 3 and 8 had
approximately 2 to 3 inches of standing water at time of monitoring. There were a few
sweetgum noted in the front portion of the site near the road but at this time the
sweetgum are not a problem.
3.4 CONCLUSIONS
Of the 50.7 acres on this site, approximately 18.2 acres involved tree planting. An
upland buffer area that consisted of 12.04 acres was planted. There were 8-vegetation
monitoring plots established throughout the planting areas. The 2004 vegetation
monitoring of the site revealed an average tree density of 375 trees per acre. This
average is above the minimum success criteria of 320 trees per acre.
1 5 3 2 1 4 9 1 1 26 40 442
2 2 2 1 1 5 2 2 15 38 268
3 2 1 2 7 7 2 4 2 5 4 5 3 7 8
4 1 3 1 5 3 2 6 21 24 595
5 1 7 1 1 4 1 4 3 7 2 5 7
6 2 1 5 1 9 31 197
7 1 12 2 4 1 5 3 1 3 32 40 544
8 4 1 1 3 2 1 3 1 5 3 2 3 1 9
T o ta l D e n s ity A v e ra g e 3 7 5
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4.0 OVERALL CONCLUSIONS/RECOMMENDATIONS
The third year for hydrologic monitoring resulted in twenty-six of the thirty-six (non-reference)
monitoring gauges showing saturation within 12” of the surface for greater
than 12.5% of the growing season. The two reference gauges, REF-37 and REF-38,
also exceeded the optimum saturation period. Ten of the thirty-six gauges did not meet
the jurisdictional success criteria for the 2004-monitoring year.
Due to the low stem counts after year one, the site was replanted in December 2002.
The site has improved with an average density of 375 trees per acre, which is above the
minimum success of 320 trees pre acre.
Per letter from the Ecosystem Enhancement Program to NCDOT dated August 25,
2004, the EEP has accepted the transfer of all off-site mitigation projects. The EEP will
be responsible for fulfilling the remaining monitoring requirements and future
remediation for this project.
APPENDIX A
GAUGE DATA GRAPHS
APPENDIX B
SITE PHOTOS & PLANTING PLAN
White Oak Creek
Photo 1 Photo 2
Photo 3 Photo 4
Photo 5 Photo 6
2004