Annual report for ... Friedburg Marsh mitigation site, Forsyth County, project no. 6.628001T, TIP no. R-2247

              ANNUAL REPORT FOR 2004
Friedburg Marsh Mitigation Site
Forsyth County
Project N0. 6.628001T
TIP No. R-2247
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 .................................................................................4
2.0 HYDROLOGY ............................................................................................4
2.1 Success Criteria ..............................................................................4
2.2 Hydrologic Description.....................................................................5
2.3 Results of Hydrologic Monitoring.....................................................5
2.3.1 Site Data...............................................................................5
2.3.2 Climatic Data ........................................................................9
2.4 Conclusions.....................................................................................9
3.0 VEGETATION..........................................................................................11
3.1 Results of Vegetation Monitoring...................................................11
3.2 Conclusions.............................................................................................11
4.0 OVERALL CONCLUSIONS/RECOMMENDATIONS ...............................12
TABLES/FIGURES/APPENDICES
Table 1. 2004 Hydrologic Monitoring Results ......................................................7
Figure 1. Friedburg Marsh Vicinity Map ...............................................................3
Figure 2. Friedburg Marsh Monitoring Gauge Locations......................................6
Figure 3. Friedburg Marsh 2004 Hydrologic Results............................................8
Figure 4. Friedburg Marsh 30-70 Percentile Graph, Yadkinville, NC .................10
Appendix A. Gauge Data Graphs
Appendix B. Site Photographs
1
SUMMARY
The following report summarizes the monitoring activities that have occurred in
2004 at the Friedburg Marsh Mitigation Site. Friedburg Marsh was constructed in
the winter of 1999 and spring of 2000. Monitoring activities in 2004 represent the
fourth year following construction. The site must demonstrate hydrologic
success during the five-year monitoring period or until the site is deemed
successful.
Friedburg Marsh is composed of existing wetlands, upland buffer areas, wetland
restoration areas, and wetland creation areas. A total of twelve groundwater-monitoring
gauges were installed on the site. There was no planting of trees or
herbaceous species at Friedburg, so vegetation monitoring is not required.
Qualitative visual observations in conjunction with the hydrologic monitoring of
the existing vegetation were made.
For the 2004 monitoring year, the data indicates that all twelve of the
groundwater gauges met the hydrologic success criterion of saturation within
twelve inches of the surface for more than 5% of the growing season. Three of
the gauges reported saturation/inundation for the entire growing season. The
vegetation in the restoration areas was dominated by wetland plant species and
included a variety of other species, as well.
In November of 2004, approximately six acres of the site were hand cleared in
order to improve the Bog Turtle habitat as recommended by Dennis Herman, the
Coordinator of Living Collections with the North Carolina Museum of Natural
Sciences.
Based on agency comments from the 2003 annual monitoring reports meeting,
NCDOT proposes to discontinue hydrology and vegetation monitoring at the
Friedburg Mitigation Site.
2
1.0 INTRODUCTION
1.1 Project Description
The Friedburg Marsh Mitigation Site, located in southern Forsyth County (Figure
1), is the easternmost known location (in North Carolina) for the bog turtle
(Clemmys muhlenbergii). The southern population of bog turtle is federally listed
as a Threatened Species due to Similarity of Appearance. Due to the diverse
wetland communities at this marsh, the Piedmont Land Conservancy and the
North Carolina Natural Heritage Program consider the site a regionally significant
natural site. The Friedburg Marsh Mitigation Plan calls for the preservation and
enhancement of the existing wetland habitat, as well as restoration and creation
of additional bog turtle habitat.
The Friedburg Marsh Mitigation Site consists of existing wetlands (3.8 acres),
upland buffer (38 acres), and wetland restoration/creation areas (5.7 acres). The
restoration/creation areas were constructed in 1999/2000 to increase hydrology
and improve bog turtle habitat. Construction activities involved filling ditches,
constructing ditch plugs, grading to reflect groundwater profiles, removing
invasive woody vegetation, and installing a new outlet for the upper pond area.
No vegetation planting was conducted.
Friedburg Marsh is located in the Muddy Creek portion of the Yadkin River Basin.
This site was created to offset wetland impacts associated with the Winston-
Salem Outer Loop (TIP No. R-2247).
1.2 Purpose
In order to demonstrate successful mitigation, hydrologic criteria must be met
during the five years of monitoring. The following report details the results of
hydrologic monitoring during the 2004-year at the Friedburg Marsh Mitigation
Site.
The 2004-year is the fourth monitoring year following site construction in 2000.
Included in this report are analyses of hydrology and vegetation monitoring
results, as well as local climate conditions throughout the growing season.
3
Figure 1. Friedburg Marsh Vicinity Map
Friedburg Marsh
Mitigation Site
Winston Salem
4
1.3 Project History
May 1997 Feasibility Study Conducted
November 1997 Site Purchased by NCDOT, Initial
Monitoring Wells Installed.
1999 Mitigation Plan Developed
Winter-Spring 2000 Grading and Construction
March 2000 Additional Monitoring Wells Installed
March-November 2001 Hydrology Monitoring (Year 1)
July 2001 Vegetation Monitoring (Year 1)
March-November 2002 Hydrology Monitoring (Year 2)
August 2002 Vegetation Monitoring (Year 2)
March-November 2003 Hydrology Monitoring (Year 3)
September 2003 Vegetation Monitoring (Year 3)
March-November 2004 Hydrology Monitoring (Year 4)
July 2004 Vegetation Monitoring (Year 4)
November 2004 Vegetation Removal – Habitat Improvement
2.0 HYDROLOGY
2.1 Success Criteria
The success criteria for hydrology states that wetland hydrology will be
established when water inundates or saturates (within 12 inches of the surface)
consecutively for 5.0 percent of the growing season.
The growing season in Forsyth County begins March 28th and ends November
10th (228 days). These dates correspond to a 50 percent probability that
temperatures will drop to 28ºF or lower after March 28 and before November 10
(Soil Survey of Forsyth County, 1976, p.63). Five percent of the growing season
translates to twelve consecutive days of inundation or saturation. Local climate
must also represent average conditions for the area.
5
2.2 Hydrologic Description
RDS WL40 and WL20 units record all groundwater and surface water data
(Figure 2). The groundwater gauges record groundwater data daily. The gauges
are downloaded in the field on a monthly basis. In November 1997, six
groundwater gauges were installed at Friedburg Marsh to monitor pre-construction
hydrology and develop a mitigation plan. Gauge 7 (DL9D90A70)
was installed to record surface water and groundwater depths. Following
construction, six additional groundwater gauges were installed, of which Gauge 6
(S4940BB) was installed to record surface water and groundwater depths.
2.3 Results of Hydrologic Monitoring
2.3.1 Site Data
The maximum number of days that the groundwater was within twelve inches of
the surface was determined for each gauge. This number was then converted
into a percentage of the 228-day growing season (March 28 – November 10).
The results are presented in Table 1 and Figure 3.
Appendix A contains a plot of the groundwater depth for each gauge. The
maximum number of consecutive days and percentage of growing season of
saturation/inundation is noted on each plot. The individual precipitation events,
shown on the monitoring gauge graphs as bars, represent data provided by the
NC State Climate Office.
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)
6
Figure 2. Friedburg Marsh Monitoring Gauge Location
7
Table 1. 2004 Hydrologic Monitoring Results
Monitoring
Gauge <5% 5% - 8% 8% - 12.5% >12.5% Actual % Success Dates
G-1
S4CFF78* r 68.4 April 2-Sept 4
Sept 7-Nov 11
G-2
S31F7FE* r 100 March 28-Nov 10
G-3
S50446C* r 100 March 28-Nov 10
G-4
S49411F* r 33.3 March 28-June 11
Sept 8-Nov 10
G-5
S50417A* r 100 March 28-Nov 10
G-6
S4940BB* r 48.7 April 2-July 1
July 23-Nov 10
G-7
DL9D90A70* r 99.1 March 30-Nov 10
G-8
DL8E8CF62* r 86.8 April 27-Nov 10
G-9
DL8E85A2* r 50.0 March 30-July 21
Sept 28-Nov 10
G-10
S213FD4 r 10.1 Oct 19-Nov 10
G-11
S51C0EB* r 28.1 March 28-May 13
Sept 8-Nov 10
G-12
S4940B9* r 48.7 April 22-July 1
July 23-Nov 10
*Gauge met the hydrology criteria during an average rainfall month (February,
April, May, July, and August).
8
Figure 3. Friedburg Marsh 2004 Hydrologic Results
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2.3.2 Climatic Data
Figure 4 is a comparison of monthly rainfall for the period of November 2003
through November 2004 to historical precipitation (collected between 1973 and
2004) for Yadkinville, North Carolina. This comparison gives an indication of how
2004 relates to historical data in terms of climate conditions. The NC State
Climate Office provided all local rainfall information.
For the 2004-year, September and November experienced above average
rainfall. The months of January, March, June, and October recorded below
average rainfall for the site, while November (’03), December (’03), February,
April, May, July, and August recorded average rainfall. Overall, 2004
experienced an average rainfall year.
2.4 Conclusions
For the 2004 monitoring year, the data indicates that all twelve of the
groundwater gauges met the hydrologic success criterion of saturation within
twelve inches of the surface for more than 5% of the growing season. Three of
the gauges reported saturation/inundation for the entire growing season.
NCDOT proposes to discontinue hydrology monitoring at the Friedburg Mitigation
Site.
10
Figure 4. 30-70 Percentile Graph
Friedburg Marsh 30-70 Percentile Graph
Yadkinville, NC
0
2
4
6
8
10
12
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'
YEAR
Precipitation
2003 Rainfall 2004 Rainfall 30th Percentile 70th Percentile
30th Percentile
70th Percentile
11
3.0 VEGETATION: FRIEDBURG MARSH
(YEAR 4 MONITORING)
3.1 Results of Vegetation Monitoring
No planting of trees or herbaceous species was undertaken as part of the
Friedburg Marsh mitigation. Therefore, no quantitative vegetation monitoring
was required. Qualitative observations of common species have been made in
conjunction with hydrologic monitoring.
The following species are found in the creation/restoration area: spike rush,
pickerel weed, bulrush, Juncus sp., cattail, poplar, and green ash are the more
wet tolerant species. Also found were: foxtail, broomsedge, beggar’s ticks,
barnyard grass, goldenrod, sweetgum, and multi-flora rose. The presence of
these species in these areas has not affected the overall quality of the bog turtle
habitat at Friedburg Marsh.
3.2 Conclusions
The vegetation in the restoration areas is dominated by wetland plant species
and includes a variety of other species, as well.
In November of 2004, approximately six acres of the site were hand cleared in
order to improve the Bog Turtle habitat as recommended by Dennis Herman, the
Coordinator of Living Collections with the North Carolina Museum of Natural
Sciences.
NCDOT proposes to discontinue vegetation monitoring at the Friedburg
Mitigation Site.
12
4.0 OVERALL CONCLUSIONS/RECOMMENDATIONS
The 2004-year is the fourth consecutive year that the Friedburg March Mitigation
Site has been monitored.
For the 2004 monitoring year, the data indicates that all twelve of the
groundwater gauges met the hydrologic success criteria of saturation within
twelve inches of the surface for more than 5% of the growing season. Three of
the gauges reported saturation/inundation for the entire growing season. The
vegetation in the restoration areas was dominated by wetland plant species and
includes a variety of other species, as well.
In November of 2004, approximately six acres of the site were hand cleared in
order to improve the Bog Turtle habitat as recommended by Dennis Herman, the
Coordinator of Living Collections with the North Carolina Museum of Natural
Sciences.
Based on agency comments from the 2003 annual monitoring reports meeting,
NCDOT proposes to discontinue hydrology and vegetation monitoring at the
Friedburg Mitigation Site.
APPENDIX A
GAUGE DATA GRAPHS
APPENDIX B
SITE PHOTOGRAPHS
Friedburg
Photo 1 Photo 2
Photo 3 Photo 4
Photo 5 Photo 6
2004