1. Southeastern Section, GSA
Hydrologic Connectivity and Water Quality Function of Coastal Plain Geographically Isolated Wetlands
March 25, 2011
Southeastern Section, GSA
Amy Keyworth, NCDENR, Division of Water Quality
Rick Bolich, NCDENR, Division of Water Quality

2. Background Wetlands contribute to water quality Clean Water Act, 1972
Prevent or control
flash flooding ۰ Surface water pollution
Erosion ۰ Loss of biodiversity
Clean Water Act, 1972
2 Supreme Court decisions
2001 – Solid Waste Agency of Northern Cook County (SWANCC)
2006 – Rapanos/Carabell 2

3. Background Geographically isolated wetlands – no Federal protection
“Significant nexus” to navigable waters
Interpreted as surface water drainage
Geographically isolated wetlands – no Federal protection
Isolated wetlands serve most of the same functions as “connected” wetlands
Habitat of amphibians that need fish-free environments to reproduce

4. Background No national policy - state by state protection
NC adopted rules
2001 – new rules
2006 – strengthened rules
Is groundwater a significant nexus? (you just can’t see it) 4

5. Objectives EPA funded grant project
Estimate acreage of Isolated Wetlands lost and mitigated
To determine the pollution absorption capacity and the water quality function of these systems
To identify and characterize the hydrological connectivity to downstream water bodies

6. 100 Miles
10 Miles
10 Miles
Bladen County
Brunswick County

7. Bladen County is covered in Carolina Bays, including several of our sites
1 Mile
Bladen County

8. Brunswick County 1 Mile 10 Miles
No Carolina Bays but perhaps an ancient scarp and plenty of sinkholes (don’t show up on map)
Brunswick County

9. Data Collection 44 cores 72 monitoring wells 3 pumping wells
Water levels
monthly point-in-time
32 automatic data-loggers
Adding stream gages
3 Aquifer tests
Water quality
Quarterly
Nutrients
Metals
Other – TOC, DOC

10. Typical Site Core site 500 Ft Cored in wetland 4 points surrounding it
streamside
500 Ft
Core site

11. Typical Site Core site Monitoring Well 500 Ft
Installed monitoring wells in a transect from the wetland to the stream
Core site
Monitoring Well
500 Ft

12. Typical Site Core site Monitoring Well Data Logger 500 Ft
Installed automatic dataloggers in at least 3 wells – wetland, upland, streamside
Core site
Monitoring Well
Data Logger
500 Ft

13. Typical Site Core site Monitoring Well Data Logger Pumping Well 500 Ft
At 3 sites installed a pumping well to perform an aquifer test
Core site
Monitoring Well
Data Logger
Pumping Well
500 Ft

14. Site BL7 – Cross-section
Monitoring well #
PW1 1 3 6 7 8 60 55 50 45 40 35 30 25
Elevation (feet)
1,000
500
This is the “simplest” site – 25 feet of undifferentiated sand overlying a hard dark gray clay
Often a gravel bed and wood chuncks at the base of the sand
Distance (feet)
Monitoring well
Pumping well
Core and Monitoring well
Well screen
Dark gray clay layer
Sandy layer
Water Level (August, 2010)

15. Site BL7 – Potentiometric surface
49.0
49.5
50.0
50.5
51.0
51.5
In all cases found that groundwater is flowing through the wetland from some higher elevation to the stream in seemingly unimpeded flow
Monitoring well
Water table contour
500 Ft

16. Site BL7 – Water Levels Taking monthly readings in all wells
Indicate that all wells respond in a similar fashion

17. Site BL7 – Water Levels
BL7-MW1S – daily ground-water levels

18. Other Findings
One site surrounded by a hardpan
250 Ft

19. Other Findings
Also found a paleochannel, drilled to 42 feet – hit clay in one but not the other
Coastal Carolina University ran GPR around this site
250 Ft

20. Other Findings Red = surficial well Blue = confined
2 aquifers, one confined or partially confined
Purple lines = shallow wells
Blue lines = deep wells
CCU did a GPR run around one of these sites
Red = surficial well
Blue = confined

21. Well # Elevation (feet) Distance (feet) 1 2 3 4 PW1 5 600 200 400 65
600
200
400 65 60 55 50 45 40 35 30 25 20 15 10

22. Conclusion Ongoing investigation Field work in NC complete May/June
The 8 isolated Coastal Plain wetlands in NC are hydrologically connected
Understanding of how these 8 systems interact with and connect to downstream water bodies
Pollution absorption capacity or the water quality function of these systems
Have not found evidence to support the meteor hypothesis of Carolina Bays

23. Acknowledgements
EPA Cooperative Agreement Number CD and CWA Section 106
NCDENR, DWQ, Wetlands Unit and Aquifer Protection Section
Virginia Baker, Rick Bolich, Rick Savage, Ross Vander Vorste, Ray Milosh
DWQ Groundwater Investigation Unit
State match
Bladen Lakes State Forest
Turnbull Creek Educational State Forest
The Nature Conservancy

24. Contact Information
contacts: 24