Annual report for ... Long Creek mitigation site, Mecklenburg County, project no. 8.U672204, TIP no. R-2248

              ANNUAL REPORT FOR 2004
Long Creek Mitigation Site
Mecklenburg County
Project No. 8.U672204
TIP No. R-2248
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 ................................................................................. 4
2.0 HYDROLOGY....................................................................................................... 5
2.1 SUCCESS CRITERIA................................................................................ 5
2.2 HYDROLOGIC DESCRIPTION ................................................................. 5
2.3 RESULTS OF HYDROLOGIC MONITORING........................................... 7
2.3.1 Site Data ......................................................................................... 7
2.3.2 Climatic Data................................................................................... 7
2.4 CONCLUSIONS ........................................................................................ 7
3.0 VEGETATION: LONG CREEK MITIGATION SITE ........................................... 11
3.1 SUCCESS CRITERIA.............................................................................. 11
3.2 DESCRIPTION OF SPECIES.................................................................. 11
3.3 RESULTS OF VEGETATION MONITORING.......................................... 11
3.4 CONCLUSIONS ...................................................................................... 11
4.0 OVERALL CONCLUSIONS AND RECOMMENDATIONS ................................. 12
LIST OF FIGURES
Figure 1. Site Location Map...................................................................................... 3
Figure 2. Long Creek Site Gauge Location Map....................................................... 6
Figure 3. 2004 Hydrologic Monitoring Gauge Results............................................... 9
Figure 4. Long Creek 30-70 Percentile Graph, Charlotte, NC................................. 10
LIST OF TABLES
Table 1. 2004 Hydrologic Monitoring Results – Groundwater Gauges .................... 8
APPENDICES
APPENDIX A GAUGE DATA GRAPHS
APPENDIX B SITE PHOTOS & VEGETATION PLOT LOCATIONS
1
SUMMARY
The Long Creek Mitigation Site is located in Mecklenburg County and was constructed
in 1996. In order to receive mitigation credit, the site must meet jurisdictional success
criteria for both wetland hydrology and vegetation for three consecutive years or until
the site is deemed successful. The following report details the monitoring activities
during the 2004-growing season. The 2004 data represents results from the seventh
year of hydrologic monitoring and the eighth year of vegetation monitoring.
The daily rainfall data depicted on the gauge data graphs was recorded from an onsite
rain gauge that was installed on May 4, 2000. Additional Charlotte rainfall data used for
the 30-70 graph was provided by the NC State Climate Office. In 2004, Charlotte
experienced an average to above average rainfall year.
For the seventh monitoring year, six of the eighteen groundwater-gauges met the
success criteria for jurisdictional hydrology (saturation within 12” of the surface for
greater than 12.5% of the growing season). Eight gauges reported saturation for less
than 5%. Three gauges reported saturation in the 5 - 8% range, while one gauge
reported saturation in the 8 – 12.5% range. Three of the four surface water gauges
indicated periodic inundation during the growing season. Surface water gauge (LCSG-
5) malfunctioned throughout the growing season.
As discussed at the 2003 annual monitoring meeting, vegetation monitoring of the Long
Creek Mitigation Site has been discontinued until completion of the highway project.
Upon completion of the project, vegetation monitoring will resume for one year. For the
2004-monitoring year, the site was visually monitored for vegetation. The nuisance tree
species were cut down on the Long Creek Site in October 2004, as requested by the
resource agencies.
NCDOT will continue to monitor the site for hydrology, in addition to the photograph
monitoring (vegetation), until the completion of the Charlotte Outer Loop.
2
1.0 INTRODUCTION
1.1 PROJECT DESCRIPTION
Located in Mecklenburg County, the Long Creek Mitigation Site encompasses
approximately 156 acres. It is situated off of Beatties Ford Road (SR 2074) and will be
bisected by the future I-485 (Figure 1). This project provides compensatory mitigation
for wetland impacts associated with sections of the proposed Charlotte Outer Loop.
The Long Creek Site was designed to restore bottomland hardwood forest wetlands. It
was originally constructed in December 1996, with 37 acres of the planting occurring in
1997. A five-acre portion, consisting of the former haul roads, was planted in early
1998. Groundwater, surface water, and rain gauges were installed in 1998. The 2004-
year is the seventh year of hydrologic monitoring and the eighth year of vegetation
monitoring at the site.
1.2 PURPOSE
Monitoring of the Long Creek Site is required to demonstrate successful mitigation. The
success of a wetland site is based primarily on federal guidelines for wetland mitigation;
these guidelines include minimum standards for hydrologic conditions and vegetation
survival. Both hydrologic and vegetation monitoring is conducted throughout the
growing season; success criteria must be met for three consecutive years. The
following report details the results of the hydrologic and vegetation monitoring for the
2004-year at the Long Creek Mitigation Site.
3
Figure 1. Site Location Map
4
1.3 PROJECT HISTORY
December 1996 Grading Construction
March 1997 Site Planted (Except 5 ac. of Haul Roads)
September 1997 Vegetation Monitoring (1 yr.)
October 1997 Monitoring Gauges Installed
March 1998 Haul Roads Planted
March- November 1998 Hydrologic Monitoring (1 yr.)
September 1998 Vegetation Monitoring (2 yr.)
March- November 1999 Hydrologic Monitoring (2 yr.)
September 1999 Vegetation Monitoring (3 yr.)
March- November 2000 Hydrologic Monitoring (3 yr.)
September 2000 Vegetation Monitoring (4 yr.)
March 2001 Site Maintenance
March- November 2001 Hydrologic Monitoring (4 yr.)
June 2001 Vegetation Monitoring (5 yr.)
March- November 2002 Hydrologic Monitoring (5 yr.)
August 2002 Vegetation Monitoring (6 yr.)
March- November 2003 Hydrologic Monitoring (6 yr.)
October 2003 Photograph Monitoring (7 yr.)
October 2004 Nuisance Tree Species Cut
November 2004 Photograph Monitoring (8 yr.)
March- November 2004 Hydrologic Monitoring (7 yr.)
5
2.0 HYDROLOGY
2.1 SUCCESS CRITERIA
In accordance with federal guidelines for wetland mitigation, the success criteria for
hydrology state that areas must be inundated or saturated (within 12 inches of the
surface) by surface or groundwater for at least a consecutive 12.5% of the growing
season. Areas inundated for 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 such factors as the presence of wetland
vegetation and hydric soils.
The growing season in Mecklenburg County begins March 22 and ends November 11
(235 days). These dates correspond to a 50% probability that air temperatures will not
drop below 28°F or lower after March 22 and before November 11.1 Minimum wetland
hydrology is required for at least 12.5% of this growing season; for Mecklenburg
County, 12.5% equals 29 consecutive days. Local climate must represent average
conditions for the area.
2.2 HYDROLOGIC DESCRIPTION
Eighteen groundwater gauges, four surface water gauges, and two rain gauges were
installed in October 1997 (Figure 2). Daily readings of the groundwater depth were
taken throughout the growing season. The 2004-year is the seventh full growing
season that the hydrology has been monitored. The rainfall data used to analyze the
site’s water level data is from onsite rain gauges.
The Long Creek Site was designed to function with rainfall as its primary hydrologic
influence. Per the original mitigation plan for this site, a section of the Charlotte Outer
Loop is scheduled for construction through the middle of the mitigation site. This new
roadway should improve the hydrology of the site through the addition of runoff.
Monitoring will continue through the construction phase of I-485 in order to determine
whether this work will have any adverse effects on the mitigation site. Current
monitoring is designed to show the influence of rainfall on site hydrology. The influence
of Long Creek itself should be reflected in the data from the surface gauges.
During a site visit in February 2001, a swale and a pipe were determined to be draining
two areas of the site. Both drainage issues were addressed in March 2001.
Maintenance work was done to stop water from leaving the site by constructing a berm
perpendicular in the swale and by placing a clay plug at the inlet of the cross pipe in
March 2001.
1 Natural Resources Conservation Service, Soil Survey of Mecklenburg County, North Carolina, p.61.
6
Figure 2. Long Creek Site Gauge Location Map
Legend
Berm to block
surface flow
Clay plug
installed at pipe
Gate installed
7
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 235-day growing season. The results are presented in Table 1.
Appendix A contains charts of the water depth for each groundwater and surface gauge.
Precipitation is shown on each graph as bars. These graphs show the reaction at each
monitoring location of the groundwater level to specific rainfall events. The maximum
number of consecutive days is noted on each graph.
The placement of the groundwater gauges and a graphical representation of the
hydrologic monitoring results are provided in Figure 3.
2.3.2 Climatic Data
Figure 4 is a comparison of 2003 and 2004 monthly rainfall to historical precipitation for
the area. This comparison indicates if 2004 was “average” in terms of climate
conditions by comparing the rainfall to that of historical rainfall (data collected between
1973 and 2004). The NC State Climate Office provided all historical data.
For the 2004-year June, July, August and September experienced above average
rainfall. The months of November (03’), January, March, April, and October recorded
below average rainfall for the site. December (03’), February, May, and November
experienced average rainfall. Overall, 2004 experienced an average to above average
rainfall year.
2.4 CONCLUSION
For the seventh monitoring year, six of the eighteen groundwater-gauges met the
success criteria for jurisdictional hydrology (saturation within 12” of the surface for
greater than 12.5% of the growing season). Eight gauges reported saturation for less
than 5%. Three gauges reported saturation in the 5 - 8% range, while one gauge
reported saturation in the 8 – 12.5% range. Three of the four surface water gauges
indicated periodic inundation during the growing season. Surface water gauge (LCSG-
5) malfunctioned throughout the growing season.
NCDOT proposes to continue hydrologic monitoring until the completion of the highway
project (Charlotte Outer Loop).
8
Table 1. 2004 Hydrologic Monitoring Results – Groundwater Gauges
Monitoring
Gauge <5% 5-8% 8-12.5% >12.5% Actual
% Dates of Success
LCW-1+ r 23.0 March 22-May 14
Sept 28-Nov 11
LCW-2 r 2.1
LCW-3 r 4.7
LCW-4 r 4.3
LCW-7 r 14.0 March 22-April 23
LCW-9 r 1.3
LCW-10 r 4.3
LCW-11 r 10.6
LCW-13 r 14.5 March 22-April 24
LCW-14 r 6.0
LCW-15 r 4.7
LCW-16 r 2.1
LCW-17 r 17.4 Sept 9-Oct 18
LCW-18 r 2.1
LCW-20 r 5.1
LCW-22 r 14.9 March 22-April 25
LCW-23 r 7.2
LCW-24 r 16.6 Sept 9-Oct 16
+ Gauge met the success criterion during an average rainfall month (February, May, and
November).
􀀀          	

   
                                 
􀀀 􀀀      
          􀀀 􀀀
      
􀀀
	
  
 
 
        
     􀀀
 
   
      
􀀀 􀀀 􀀀
􀀀
􀀀􀀀  􀀀
􀀀􀀀 
􀀀
􀀀􀀀 􀀀
􀀀
􀀀
􀀀
􀀀
􀀀
􀀀􀀀 􀀀 
􀀀
􀀀
􀀀
  	
   
   
   
   

   	
    
    
    
    
    
    
  	 
  		
  	 
  	 
   
   
   
   
   
    
  	

    
􀀀               
􀀀           
10
Figure 4. 30-70 Percentile Graph
Long Creek 30-70 Percentile Graph
Charlotte, NC
0
1
2
3
4
5
6
7
8
9
Nov 03' Dec 03' Jan 04' Feb 04' Mar 04' Apr 04' May Jun 04' Jul 04' Aug Sep 04' Oct 04' Nov 04' Dec 04'
Month
Precipitation (in.)
2003 Rainfall 2004 Rainfall 30th Percentile 70th Percentile
*
30th Percentile
70th Percentile
11
3.0 VEGETATION: LONG CREEK MITIGATION SITE
(YEAR 8 MONITORING)
3.1 SUCCESS CRITERIA
The success criteria state that there must be a minimum mean density of 320 trees per
acre of approved target species surviving for at least three years.
3.2 DESCRIPTION OF SPECIES
The following tree species were planted in the Wetland Restoration Area:
Fraxinus pennsylvanica, Green Ash
Fraxinus caroliniana, Carolina Ash
Betula nigra, River Birch
Quercus phellos, Willow Oak
Liriodendron tulipifera, Tulip Poplar
Quercus michauxii, Swamp Chestnut Oak
Quercus falcata var. pagodaefolia, Cherrybark Oak
Ulmus americana, American Elm
3.3 RESULTS OF VEGETATION MONITORING
As discussed in the 2003 annual monitoring meeting, vegetation monitoring of the Long
Creek Mitigation Site has been discontinued until completion of the highway project.
Upon completion of the project, vegetation monitoring will resume for one year.
Photograph monitoring will continue until project completion.
3.4 CONCLUSIONS
Approximately 37 acres of this site were planted in bottomland hardwoods in March
1997. The remaining five acres were planted in March 1998. There were six
vegetation-monitoring plots established throughout the planting areas. Vegetation
monitoring has been discontinued until the completion of highway project.
The nuisance tree species were cut down on the Long Creek Site in October 2004, as
requested by the resource agencies. The photographs illustrate before and after the
cutting project.
NCDOT will continue photograph monitoring at the Long Creek Mitigation Site.
12
4.0 OVERALL CONCLUSIONS AND RECOMMENDATIONS
For the seventh monitoring year, six of the eighteen groundwater-gauges met the
success criteria for jurisdictional hydrology (saturation within 12” of the surface for
greater than 12.5% of the growing season). Eight gauges reported saturation for less
than 5%. Three gauges reported saturation in the 5 - 8% range, while one gauge
reported saturation in the 8 – 12.5% range. Three of the four surface water gauges
indicated periodic inundation during the growing season. Surface water gauge (LCSG-
5) malfunctioned throughout the growing season.
As discussed at the 2003 annual monitoring meeting, vegetation monitoring of the Long
Creek Mitigation Site has been discontinued until completion of the highway project.
Upon completion of the project, vegetation monitoring will resume for one year. For the
2004-monitoring year, the site was visually monitored for vegetation. The nuisance tree
species were cut down on the Long Creek site in October 2004, as requested by the
resource agencies.
NCDOT will continue to monitor the site for hydrology, in addition to the photograph
monitoring (vegetation), until the completion of the Charlotte Outer Loop.
14
APPENDIX A
GAUGE DATA GRAPHS
APPENDIX B
SITE PHOTOS & VEGETATION PLOT LOCATIONS
Long Creek (Before Cutting)
Photo 1 Photo 2
Photo 3 Photo 4
Photo 5 Photo 6
2004
Long Creek (After Cutting)
Photo 1 Photo 2
Photo 3 Photo 4
Photo 5 Photo 6
2004