ANNUAL REPORT FOR 2003
Gurley Mitigation Site
Greene County
Project No. 8.T340306
TIP No. R-1023WM
Prepared By:
Office of Natural Environment & Roadside Environmental Unit
North Carolina Department of Transportation
December 2003 TABLE OF CONTENTS
SUMMARY......................................................................................................................1
1.0 INTRODUCTION..................................................................................................2
1.1 PROJECT DESCRIPTION.........................................................................2
1.2 PURPOSE.................................................................................................2
1.3 PROJECT HISTORY.................................................................................4
1.4 DEBIT LEDGER........................................................................................5
2.0 HYDROLOGY......................................................................................................6
2.1 SUCCESS CRITERIA................................................................................6
2.2 HYDROLOGIC DESCRIPTION.................................................................6
2.3 RESULTS OF HYDROLOGIC MONITORING...........................................8
2.3.1 Site Data.........................................................................................8
2.3.2 Climatic Data.................................................................................11
2.4 CONCLUSIONS......................................................................................11
3.0 VEGETATION....................................................................................................13
3.1 SUCCESS CRITERIA..............................................................................13
3.2 DESCRIPTION OF SPECIES..................................................................13
3.3 RESULTS OF VEGETATION MONITORING..........................................15
3.4 CONCLUSIONS......................................................................................16
4.0 OVERALL CONCLUSIONS/RECOMMENDATIONS.........................................16 LIST OF FIGURES
Figure 1. Site Location Map ...........................................................................................3
Figure 2. Monitoring Gauge Locations ........................................................................... 7
Figure 3. Hydrologic Monitoring Results.......................................................................10
Figure 4. Gurley 30-70 Percentile Graph......................................................................12
LIST OF TABLES
Table 1. Gurley Tract Mitigation Site Debit Ledger......................................................... 5
Table 2. Hydrologic Monitoring Results..........................................................................8
Table 3. Hydrologic Monitoring Results (1998-2002)……………………………………….9
Table 4. Vegetation Monitoring Statistics, By Zone and Plot........................................15
APPENDICES
APPENDIX A GAUGE DATA GRAPHS
APPENDIX B UPLAND LEVEE REPAIR PICTURE
APPENDIX C SITE PHOTOS
SUMMARY
The following report summarizes the monitoring and construction activities during 2003 at the Gurley Mitigation Site in Greene County. Originally constructed in 1997, the site provides compensatory wetland mitigation for several NCDOT projects in the Neuse River Basin. In June 2001, the site was delineated in order to verify that the site covered existing permit requirements. The Army Corps of Engineers approved the delineation in June 2001. The confirmed wetland delineation map that was produced from this exercise was included in the 2001 annual report.
The site is monitored with 16 groundwater-monitoring gauges, three surface water gauges, and one rain gauge. The hydrologic success criterion varies for each gauge, depending upon its location within the site. Per the request of the Corps of Engineers, the hydrologic monitoring requirements of the site were changed from the requirements stated in the approved mitigation plan. The riverine portion of the site must show saturation within 12” of the surface for 12.5% of the growing season, while the non-riverine areas must show saturation within 12 inches of the surface for at least 8% of the growing season. Vegetation planting occurred in four zones, with multiple plots in each.
Repairs were made to portions of the upland levee area in December 2003. The repairs were needed due to extensive washes along a portion of the levee adjacent to the beaver impoundment (See photo Appendix B). A gate will be added on the levee to prevent further public access.
Six non-riverine and two riverine gauges are located outside of the wetland extents based on the approved wetland delineation (2001). The results from these gauges are documented in Table 2, however the success of the site should not be influenced by the data reported for these gauges. Hydrologic monitoring in 2003 indicated that two riverine gauges recorded saturation within 12” of the surface for more than 12.5% of the growing season. Five non-riverine gauges recorded saturation for more than 8% of the growing season. Two riverine gauges and one non-riverine gauge that met the success criterion could not be downloaded due to high water from beaver activity. All three surface gauges indicated inundation throughout the growing season.
The success criteria for vegetation is that a minimum survival rate of 320 trees per acre is required after three years; this minimum requirement is reduced by 10% for two years following the third year of monitoring. Vegetation monitoring yielded an average tree density of 486 trees per acre, which is well above the minimum success criterion of 320 trees per acre.
The 2003-year represents the sixth consecutive monitoring season for vegetation and hydrology. Based on the sixth year of monitoring and the delineation approved by the Army Corps of Engineers (2001), NCDOT proposes that vegetation and hydrology monitoring be discontinued on the Gurley Mitigation Site.
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1.0 INTRODUCTION
1.1 Project Description
The Gurley Tract Mitigation Site is located in Greene County, approximately 12 miles northeast of Goldsboro (Figure 1). The site provides 170 acres of riverine and non-riverine restoration and enhancement. The Gurley Tract provides compensatory mitigation for several projects in the Neuse River Basin. The following plant communities are included in the site: Coastal Plain Bottomland Hardwood Swamp, Non-Riverine Wet Hardwood Forest, streambed Atlantic White Cedar Forest, and Cypress/Tupelo Swamp.
1.2 Purpose
In order to demonstrate successful mitigation, the site must achieve success for 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 describes the results of the hydrologic and vegetation monitoring during the 2003-growing season at the Gurley Tract Mitigation Site. Included in this report are analyses of both hydrologic and vegetative monitoring results, as well as local climate conditions throughout the growing season. Updated site photographs have also been provided.
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Figure 1. Site Location Map
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1.3 Project History
The site was initially monitored for both wetland hydrology and vegetation in 1998. Since then, additional work has been completed on the mitigation site. 2003 represents the sixth year of both hydrologic and vegetation monitoring; however it is the fifth year of monitoring following additional planting and remediation work in 1999.
December 1997 Site Constructed
January 1998 Site Planted
Spring 1998 Monitoring Gauges Installed
May - November 1998 Hydrologic Monitoring (1 yr.)
October 1998 Vegetation Monitoring (1 yr.)
February 1999 Zone 4 (Atlantic White Cedar Area) Planted
March - November 1999 Hydrologic Monitoring (2 yr.)
August 1999 Remediation on Nahunta Swamp Bank
September & October 1999 Vegetation Monitoring (2 yr.)
March - November 2000 Hydrologic Monitoring (3 yr.)
October 2000 Vegetation Monitoring (3 yr.)
March - November 2001 Hydrologic Monitoring (4 yr.)
June 2001 Wetland Delineation of Site
June 2001 Vegetation Monitoring (4 yr.)
August-September 2001 GPS Mapping of Beaver Impoundment
March – November 2002 Hydrologic Monitoring (5 yr.)
September 2002 Vegetation Monitoring (5 yr.)
March – November 2002 Hydrologic Monitoring (6 yr.)
September 2003 Vegetation Monitoring (6 yr.)
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1.4 Debit Ledger
Table 1. Gurley Tract Mitigation Site Debit Ledger
Mitigation Plan
TIP Debit
Site Habitat
Acres at Start
Acres Remaining
Percent Remaining
Ratios
R-525 D
R-1023 AB B
B-3070
R-2001 B
R-2719 BA
R-525 G
U-3472
R-1030
SPH Restoration (RR)
26.92
4.84
17.98
1:5:1
1.48
12.66
1.19
4.68
2.07
BLH Restoration (NRR)
27.83
-12.18
-43.77
2:01
1.08
34.58
3.76
0.59
BLH Enhancement
26.92
-18.88
-70.13
4:01
45.8
SPH Preservation
5.9
0
0.00
10:01
5.9
Beaver
Impoundment
20.61
20.61
100.00
Total
87.57
-26.22
-29.94
SPH: Swamp Hardwood BLH: Bottomland Hardwood RR: Riverine NRR: Non-riverine
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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 inches of the surface) by surface or ground water for at least a consecutive 12.5% of the growing season. Areas inundated less than 5% of the growing season are always classified as non-wetlands. Areas inundated between 5% and 12.5% of the growing season can be classified as wetlands depending upon factors such as the presence of hydrophytic vegetation and hydric soils.
Upon request of the US Army Corps of Engineers, the hydrologic monitoring requirements for the Gurley Tract Site have been altered from the original mitigation plan. The new success criteria state that the riverine portions of the site must be saturated within 12 inches of the surface for at least 12.5% of the growing season. The non-riverine areas must be saturated for at least 8% of the growing season. Monitoring will be conducted for a total of five years. The riverine and non-riverine portions of the site are illustrated in Figure 2; riverine areas are shaded on this map.
According to the Soil Conservation Service, the growing season in Greene County extends from March 17 to November 15, approximately 244 days. A consecutive 12.5% of the growing season for Gurley Tract would equal 30.5 days; a consecutive 8% would be equivalent to 19.5 days. Local climate must represent average conditions for the area in order for the hydrologic data to be valid.
2.2 Hydrologic Description
Sixteen groundwater, three surface water, and one rain gauge are used on the Gurley Tract to monitor site hydrology (Figure 2). The automatic monitoring gauges record the depth to the groundwater level. Daily groundwater and rainfall measurements were taken throughout the growing season; the surface water gauges record water levels every three hours.
Appendix A contains a plot of the water depth for each of the monitoring and surface gauges for 2003. Precipitation events, measured by the onsite rain gauge, are included on each graph as bars.
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Figure 2. Monitoring Gauge Locations
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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 244-day growing season. Table 2 presents the hydrologic results for 2003. Figure 3 is a graphical representation of the hydrologic monitoring results for 2003.
Table 2. 2003 Hydrologic Monitoring Results
Monitoring Gauge
< 5%
5-8%
8-12.5%
>12.5%
Actual %
Dates of Saturation
NON-RIVERINE (Success = saturation for 8% of the growing season)
GW-1
r
8.2
Outside of
Delineation
GW-2+
r
23.0
March 17-May 11
GW-3
r
0.4
Outside of
Delineation
GW-5
r
2.5
GW-7
r
1.6
Outside of
Delineation
GW-9
r
0.8
Outside of
Delineation
GW-10
r
7.0
Outside of
Delineation
GW-11+
r
100
March 17-Nov 15
GW-12+
r
55.7
March 17-June 26
July 3-Nov 15
GW-13+
r
44.7
April16-Aug 2
GW-15*
r
-
Standing water
GW-16
r
1.6
Outside of
Delineation
RIVERINE (Success = saturation for 12.5% of the growing season)
GW-4*
r
0.4
Outside of
Delineation
GW-6+
r
29.5
March 17-May 27
Sept 12-Nov 15
GW-8*
r
-
Standing water
GW-14
r
7.4
Outside of
Delineation
* Gauge could not be downloaded due to standing water at gauge location.
+ Gauge met during an average month of rainfall (March and May).
• Gauges that are highlighted in Table 2 are located outside of the Corps of Engineers approved wetland delineation.
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• Gauges GW-8 and GW-15 could not be downloaded during the majority of the growing season due to standing water related to the beaver activity.
Table 3. Hydrologic Monitoring Results (1998-2002)
Monitoring Gauge
1998 % Results
1999 % Results
2000 %
Results
2001 % Results
2002 % Results
NON-RIVERINE (Success = saturation for 8% of the growing season)
GW-1
2.9
3.7
7.0
10.2
14.8
GW-2
8.7
1.2
7.9
8.6
4.9
GW-3
Not installed
0
0.8
1.6
0
GW-5
.8
0.4
12.8
2.5
15.2
GW-7
1.2
1.2
1.7
1.6
1.2
GW-9
0
0
0
0
0
GW-10
Not installed
Not installed
2.1
4.5
3.3
GW-11
2.5
30.3
24.0
23
28.7
GW-12
47.1
31.6
32.6
44.3
31.9
GW-13
47.1
34.4
47.9
67.2
22.1
GW-15
24.4
68.8
43
100
100
GW-16
Not installed
0.4
0
0.8
0.8
RIVERINE (Success = saturation for 12.5% of the growing season)
GW-4
0
0
0
0
0
GW-6
18.2
14.3
52.5
100
33.2
GW-8
41.3
59.4
54.1
100
100
GW-14
Not installed
3.7
7.9
2.0
10.6
Climate Conditions
Average Rainfall
Not Available
Average Rainfall
Below Average Rainfall
Below Average Rainfall
Table 3 represents hydrologic data in percentages from the previous years (1998-2002).
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2.3.2 Climatic Data
Figure 4 is a comparison of 2002-2003 monthly rainfall to historical precipitation for the area. The two lines represent the 30th and 70th percentiles of monthly precipitation for Goldsboro, NC. The bars are the monthly rainfall totals for 2002 and 2003. The NC State Climate Office provided the historical data.
For the 2003-year, November (02’), February, April, and July experienced above average rainfall. The months of January, June, August, September, October, and November recorded below average rainfall for the site. December (02’), March, and May experienced average rainfall. Overall, 2003 experienced an average rainfall year.
2.4 CONCLUSIONS
Hydrologic monitoring in 2003 indicated that two riverine gauges recorded saturation within 12” of the surface for more than 12.5% of the growing season. Five non-riverine gauges recorded saturation for more than 8% of the growing season. Two riverine gauges and one non-riverine gauge that met the success criterion could not be downloaded due to high water from beaver activity. All three surface gauges indicated inundation throughout the growing season.
The 2003-year is the sixth consecutive year that hydrology has been monitored. Based on the monitoring data and the jurisdictional wetland delineation, NCDOT proposes to discontinue hydrology monitoring on the Gurley Mitigation Site.
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Figure 4. 30-70 Percentile Graph, Goldsboro, NC 30-70 Percentile GraphGoldsboro, NC01234567Nov 02'Dec 02'Jan 03'Feb 03'Mar 03'Apr 03'MayJun 03'Jul 03'AugSep 03'Oct 03'Nov 03'Dec 03'MonthPrecipitation (in)2002 Rainfall2003 Rainfall30 Percentile70 Percentile30th Percentile70th Percentile
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3.0 VEGETATION: GURLEY MITIGATION SITE
(YEAR 6 MONITORING)
3.1 Success Criteria
The March 1998 Mitigation Plan states that there must be a minimum of 320 trees per acre living for at least three consecutive years.
Subsequent permit conditions associated with the site state that NCDOT will monitor the site for five years. The 320 stems per acre survival criterion for planted seedlings was used to determine success for the first three years. The required survival criterion was decreased 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 Restoration Area:
Zone 1: Coastal Plain Bottom-Land Hardwood Forest (18.86 acres)
Taxodium distichum, Baldcypress Fraxinus pennsylvanica, Green Ash Quercus falcata var. pagodaefolia, Cherrybark Oak Quercus michauxii, Swamp Chestnut Oak Quercus phellos, Willow Oak Quercus nigra, Water Oak Nyssa aquatica, Water Tupelo Quercus lyrata, Overcup Oak
Nyssa sylvatica var. biflora, Swamp Blackgum
Carpinus caroliniana, American Hornbeam
Zone 2: Non-Riverine Wet Hardwood Forest (17.57 acres)
Taxodium distichum, Baldcypress Fraxinus pennsylvanica, Green Ash Quercus falcata var. pagodaefolia, Cherrybark Oak Quercus michauxii, Swamp Chestnut Oak Quercus phellos, Willow Oak Quercus nigra, Water Oak Quercus alba, White Oak Pinus serotina, Pond Pine Platanus occidentalis, American Sycamore Nyssa aquatica, Water Tupelo Quercus lyrata, Overcup Oak Liriodendron tulipifera, Tulip Poplar
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Nyssa sylvatica var. biflora, Swamp Blackgum
Carpinus caroliniana, American Hornbeam
Zone 3: Streambank Levee Forest (3 acres)
Quercus michauxii, Swamp Chestnut Oak Quercus alba, White Oak Pinus serotina, Pond Pine Platanus occidentalis, American Sycamore Quercus lyrata, Overcup Oak
Salix nigra, Black Willow Betula nigra, River Birch
Zone 4: Atlantic White Cedar Forest (7 Acres) Planted February 1999*
Chamaecyparis thyoides, Atlantic White Cedar Nyssa aquatica, Water Tupelo Fraxinus pennsylvanica, Green Ash Quercus falcata var. pagodaefolia, Cherrybark Oak
Nyssa sylvatica var. biflora, Swamp Blackgum
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3.3 Results of Vegetation Monitoring
Table 4: Vegetation Monitoring Statistics 1211137261010413159636373962793123945589T12810123112831614T31431725462T42133068T5541321537276ZONE 1 AVERAGE DENSITY4412434738355331455555651365457421385249761326511173115050680ZONE 2 AVERAGE DENSITY578419321433288T21116447234747680ZONE 4 AVERAGE DENSITY484TOTAL AVERAGE DENSITY486
Zone 1: Other species noted: trumpet creeper, Aster sp., fennel, winged sumac, broomsedge, woolgrass, cane, blackberry, muscadine, plume grass, Juncus sp., Baccharis sp., river birch, red maple, briars, and sweetgum. 18-24 inches of standing water noted in plot T4, 8-16 inches of standing water noted in T5. Beaver activity evident in plot T4.
Zone 2: Other species noted: trumpet creeper, Baccharis sp., fennel, red maple, Aster sp., honeysuckle, holly, broomsedge, sicklepod, sweetgum, and pine.
Zone 3: Trees surviving along levee.
Zone 4: Other species noted: black willow, Juncus sp., smartweed, jewelweed, alder, cattails, and volunteer oaks.
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3.4 Conclusions
Of the 426 acres on this site, approximately 46 acres involved tree planting. There were 6 test plots and 5 transects established throughout the planting areas. The 2003 vegetation monitoring of the planted areas revealed a total average density of 486 trees per acre. This average is well above the minimum requirement of 260 trees per acre.
NCDOT proposes to discontinue vegetation monitoring at the Gurley Mitigation Site.
4.0 OVERALL CONCLUSIONS/RECOMMENDATIONS
Monitoring activities in 2003 represent the sixth year of hydrologic monitoring at the Gurley Tract Mitigation Site. Hydrologic monitoring for 2003 indicated that two riverine gauges recorded saturation within 12” of the surface for more than 12.5% of the growing season. Five non-riverine gauges recorded saturation for more than 8% of the growing season. Two riverine gauges and one non-riverine gauge that met the success criterion could not be downloaded due to high water from beaver activity. All three surface gauges indicated inundation throughout the growing season
During the sixth year of vegetation monitoring, the site yielded an overall average survival rate of 486 trees per acre over four planting zones. This is well above the minimum requirement. NCDOT proposes to discontinue vegetation monitoring at the Gurley Mitigation Site.
The 2003-year represents the sixth consecutive monitoring season for hydrology and vegetation. Based on the monitoring data and the jurisdictional delineation (approved by the Army Corps of Engineers in 2001), NCDOT proposes that hydrology and vegetation monitoring be discontinued at the Gurley Mitigation Site.
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APPENDIX A
GAUGE DATA GRAPHSAPPENDIX B
UPLAND LEVEE REPAIR PICTUREAPPENDIX C
SITE PHOTOSGurley
Photo 1 Photo 2
Photo 3 Photo 4
Photo 5 Photo 6
2003 Photo 7 Photo 8
Photo 9
2003