This project explores the remediation a Santee Cooper Coal Ash Pond and the wetland restoration of the site.

1. Wetland Restoration in an Industrial
Coal Ash Pond in Granger, SC
Paige Kimble, Rachel Mordovancy, Ramona Kahler

2. Introduction: Coal-Powered Generation
● 20% of South Carolina’s electricity is coal generated
○ Over 50% decrease in coal generation than a decade ago
● Coal power plants: organic material in coal is burned at high temperatures
● What is left is called coal ash
○ Contains concentrated amounts of arsenic, lead, mercury, and other heavy
metals along with aluminum, cobalt, manganese, zinc, etc.
■ These metals are found naturally
■ Concentrations of these materials make coal and coal ash toxic

3. Introduction: Coal-Powered Generation
Coal energy
generation
process
Photo Courtesy of
https://www.fossilconsu
lting.com/2020/01/09/s
upplanting-upgrading-
coal-ash-ponds/

4. Introduction: Coal Ash Ponds
● Less coal generation → more ash ponds
closures
● More strict mandates → more ash pond
closures
○ Two methods for closing ash ponds:
■ Cover in place - temporary but
cheap solution; allowed for lined
ash ponds
■ Closure by removal - removing
all ash and contaminated soil
● Use the land for
something else
● Convert land back to
original state
Diagram of a Cover in Place ash pond
Photo courtesy of https://www.northcarolinahealthnews.org/2018/02/18
/fate-most-duke-energy-coal-ash-uncertain/

5. Site Details
● Modeled after the Santee Cooper Ash Pond
located at closed Grainger Generating
Station
○ Original ash pond was created on a
wetland
■ Surrounding environment is suited
for wetlands (soil quality,
presence of an adjacent river,
some surrounding wetland
vegetation, etc.)
○ The groundwater is impacted by the
ash
■ Aspect of engineering
management
Santee Cooper Ash Pond located at closed Grainger
Generating Station in South Carolina

6. Closure by Removal Plan
● Detailed closure plans available online
● Ash Pond Closure Plan:
○ Dewater pond under appropriate guidelines
○ Remove ash
■ Class III landfill
■ Beneficially reuse
○ Partially fill ash pond → drainage and restoration
● Post Closure Plan
○ Ensures remediation and maintains effectiveness
○ Groundwater monitoring every 3-6 months
○ Make design corrections for erosion
Ash Pond being closed by removal
Photo courtesy of
http://www.rpmsolve.com/services/coal-
combustion-residuals

7. Wetland Restoration
Steps to Wetland Restoration:
● Evaluating Compensatory Mitigation
● Restoring Hydrology
○ Water Control Structures
○ Topography
● Restoring Native Flora
● Recovery Monitoring

8. Compensatory Mitigation
● No Net Loss of Wetlands
● Restoring a wetland is the process of
mitigation banking where mitigation credits
are earned for a wetland restoration.
● Earning mitigation credits requires an
approved, designed restoration
● Credits earned from a mitigation bank can be
sold to developers to compensate for
construction projects impacting wetlands.
● The Army Corps of Engineers and SCDHEC
monitor and approve credits

9. RIBITS
● US ACE uses the Ratio Method for quantifying wetland recovery for many locations
● The amount of credits given to a restoration project are based on the value of the wetland
and the intensity of the project (restoration, enhancement, preservation)

10. Restoring Hydrology
● One of the most important aspects of restoring a
wetland is ensuring proper hydrological periods.
● First, one must determine the volume stored in the
wetland.
● Then the water budget must be calculated.
● Factors affecting the water budget and storage.
○ Groundwater
○ Direct Precipitation
○ Evaporation
○ Transpiration
○ River Flow

11. Water Control Structures
● Water control structures must be designed
with the water budget and storage capacity in
mind
○ Design depth of wetland
● Dikes surrounding the wetland will be broken
to input a weir and chute at the inlet and
outlet of the wetland.
○ Inlet/Outlet chutes will be constructed
as vegetative spillways
● An emergency spillway will also be
constructed

12. Topography
● Topographic complexity promotes diverse
hydroperiods and enhances the
development of the plant and animal
community.
● Topography is to be designed with micro
(smaller than 6” in elevation) and
macrotopography
● Mounds provide:
○ Habitats
○ Diverse Vegetation
○ Help Directing Flow Path
Topography and the Wetland Community:
○ Amphibians: prefer microtopographic
depressions seasonally inundated with
water
○ Waterfowl: deep swales of open water
○ Wading Birds: Shallow shorelines from
Irregular ponding shapes and large
depressions with a flat slope

13. Budget Considerations
● Wetland restoration is an expensive
project.
● Creative borrowing should be
utilized
○ Using fill from created depressions to
construct mounds
○ Excavation should not occur near the
dikes to prevent erosion or burrowing
rodents from compromising the
structure.

14. Revegetation
● Bulrushes
● Spikerushes
● Sedges
● Rushes
● Grasses

15. Methods of Flora Reintroduction
● Planting, where saplings are planted by hand or through mechanical means, is a highly intensive
process
● Direct Seeding, with seeds being hand sown or mechanically sown
● Brush Matting, which can provide seeds and cover for reducing overland flow and increasing
infiltration. This should not be done if there is not an excess of brush in the area the brush is
taken from.
● Transferring Leaf Litter, which can bring seeds, fungi, bacteria and more from an already
established site, can also bring along disease.
● Transplanting is an option which is viable for some soils, but factors such as moisture content
must be considered

16. Recovery
Two ways of measuring wetland recovery are by productivity and diversity
A more intensely restored wetland will typically have higher productivity at the
cost of lower diversity

17. Follow-up
● Monitoring
○ Productivity
○ Diversity
○ Water Quality
○ Hydroperiods
● Making small changes if goals are not being met as expected
○ Hydrological changes
○ Replanting
● Allowing for self-design to maintain the site once restoration is done

18. Final Thoughts/Overview
Ash Pond Closure
Restoration
Revegetation
Mitigation Credits (RIBITS)

19. References
● ●U.S. Energy Information Administration - EIA - Independent Statistics and Analysis.” South Carolina - State Energy Profile Analysis - U.S. Energy Information Administration (EIA),
www.eia.gov/state/analysis.php?sid=SC.
● ●“Coal Ash: Hazardous to Human Health.” Physicians for Social Responsibility (PSR). https://www.psr.org/wp-content/uploads/2018/05/coal-ash-hazardous-to-human-health.pdf.
● ●Aronson, M. and Glatowitsch (2008). S. Long-term vegetation development of restored prairie pothole wetlands. Wetlands, Vol. 28, No. 4, pp. 883-895.
● ●Mitsch, W. et al (2012). Creating Wetlands: Primary Succession, Water Quality Changes, and Self-Design over 15 Years. Bioscience, Vol. 62, No. 3, pp. 237-250.
● ●Blomqvist, M. et al (2003). Restoration of ditch bank plant species richness:The potential of the soil seed bank. Applied Vegetation Science, Vol. 6, pp 179-188.
● ●United States Environmental Protection Agency. # 20 Wetland Hydrology # 20 Wetland Hydrology. 2008, No. December.
● ●Natural Resources Conservation Service. Engineering Chapter 13 Wetland Restoration , Enhancement , or Creation. U. S. Dep. Agric. Soil Conserv. Serv. Eng. F. Handb. 1997, 210-EFH, 1
(May).
● ●Wetland Science Institute. Wetland Restoration, Enhancement, and Management. Nat. Resour. Conserv. Serv. 2003, 375.
● ●https:/https://telluriumpartners.com/mitigation-banking-guide/
● ●https://www.nps.gov/subjects/wetlands/restoring-wetlands.htm
● ● Conservation Management Notes Managing bushland and wildlife habitat. New South Wales Department of Planning, Industry, and Environment. Retrieved from
https://www.environment.nsw.gov.au/resources/cpp/Revegetation.pdf
● ●The Ratio Method. United States Army Corps of Engineers Assessment Tools. Retrieved from
https://ribits.usace.army.mil/ribits_apex/f?p=107:27:721720919616::NO::P27_BUTTON_KEY:23
● ●Kentula, Mary E. Restoration, Creation, and Recovery of Wetlands Wetland Restoration and Creation. US Environmental Protection Agency. Retrieved from
https://water.usgs.gov/nwsum/WSP2425/restoration.html

20. Questions?
Topics Discussed:
● Coal generation and coal ash
● Ash pond closure
● Wetland restoration and associated complications
● Mitigation credits
● Restoration follow-up