NC0004961_RBSS Excavation Plan 2016_20161113

Riverbend Steam Station

Coal Ash Excavation Plan

2016 Update

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Table of Contents
I. Statement of Purpose ................................................................................................................... 1
II. General Facility Description ......................................................................................................... 2
III. Project Charter ............................................................................................................................... 4
IV. Critical Milestone Dates................................................................................................................ 5
V. Erosion and Sedimentation Control Plan .................................................................................. 6
VI. Dewatering Plan ............................................................................................................................ 6
VII. Approved Location- for Removed Ash ....................................................................................... 7
VIII. Transportation Plan ....................................................................................................................... 8
IX. Environmental and Dam Safety Permitting Plan ...................................................................... 9
X. Contracting Strategy ................................................................................................................... 11
XI. Environmental, Health, and Safety Plan .................................................................................. 11
XII. Communications Plan ................................................................................................................. 12
XIII. Glossary ........................................................................................................................................ 12
XIV. Reference Documents ................................................................................................................ 14

Exhibits
Exhibit A: Excavation Soil Sampling Plan

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I. Statement of Purpose
Duke Energy Carolinas, LLC (Duke Energy or the Company) is required by Part II,
Section 3(b) of the Coal Ash Management Act of 2014 (Session Law 2014-122) (Coal
Ash Act or Act) to close, in accordance with Part II, Section 3(c) the coal combustion
residuals (CCR) surface impoundments located at the Riverbend Steam Station
(Riverbend or Plant), National Pollutant Discharge Eliminations System Permit No.
NC0004961 in Gaston County as soon as practicable, but not later than August 1, 2019.
This Coal Ash Excavation Plan (Plan) represents activities to satisfy the requirements
outlined in Part II, Sections 3(b) and 3(c), Subparagraphs 1 and 2 of the Act and the
requests set forth in the North Carolina Department of Environment Quality’s (NC DEQ)
August 13, 2014 letter titled “Request for Coal Ash Excavation Plans for Asheville
Steam Electric Generating Plant, Dan River Combined Cycle Station, Riverbend Steam
Station, L.V. Sutton Electric Plant” (NC DEQ Letter).
The NC DEQ Letter was sent by the North Carolina Department of Environment and
Natural Resources, which was renamed the North Carolina Department of
Environmental Quality by Session Bill 2015-241. The NC DEQ Letter specifically
requests that the Plan include 1) soil and sedimentation erosion control measures, 2)
dewatering, and 3) the proposed location(s) of the removed ash. These requirements
are found in this updated Plan.
This is a revision of the Coal Ash Excavation Plan dated November 13, 2015, which
covers the initial phase of ash basin excavation activities, including the initiation of basin
dewatering, site preparation, ash basin preparation and ash removal from the basins at
Riverbend. The Plan will generally be updated and submitted to NC DEQ annually.
The Plan covers some of the work required by Part II, Sections 3(b) and 3(c) of the Coal
Ash Act. The Act requires the closure of the ash basins as soon as practicable, but no
later than August 1, 2019. However, the Act contains no requirement for the submittal
of an excavation plan of the kind presented here. Thus, while the formulation, submittal,
and review of this Plan will assist in Duke Energy’s work to close the ash basin, its
ultimate approval is an action not specifically required by statutory, regulatory, or other
applicable authority.
The scope of work in excavating the ash basins has been determined by applicable
laws, rules, permits, and approvals that control the activities to be performed under the
Plan. There are several external and internal factors that could potentially affect the
precise scope of the work to be performed under the Plan. As a consequence, neither
the submittal of this Plan nor its acknowledgement by NC DEQ should be taken as
requiring actions different from such applicable requirements . Duke Energy submits this
Plan to NC DEQ based on the understanding that it may be necessary to take actions

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that deviate from the Plan in the future, and the Company reserves the right to make
such changes.

II. General Facility Description
Riverbend is located off of Horseshoe Bend Beach Road near the town of Mt. Holly in
Gaston County, NC on the south bank of the Catawba River. The seven-unit Station
began commercial operation in 1929 with two units and then expanded to seven by
1954. At its peak, the generating facility had a capacity of 454 megawatts. As of April
1, 2013, all of the coal-fired units were retired.
The CCR from Riverbend’s coal combustion operations was historically processed in
the ash basin system located on the northeast side of the property adjacent to the
Catawba River. The discharge from the ash basin system is permitted through Outfall
#002 to the Catawba River in the Catawba River Basin by NC DEQ’s Division of Water
Resources under National Pollutant Discharge Elimination System (NPDES) Permit No.
NC0004961. Riverbend has been decommissioned and no active ash placement or
sluicing is occurring within the ash basin system.
Duke Energy’s Coal Combustion Residuals Removal Verification Procedure (Removal
Verification Procedure) will be used to verify that primary source ash has been removed
from the basin. Subsequent to removal of the ash pursuant to the Removal Verification
Procedure, Duke Energy will implement its Excavation Soil Sampling Plan (ESSP),
which was developed for the purpose of meeting the applicable performance standard.
Although not required under CAMA, in September 2016, NC DEQ sent Coal
Combustion Residuals Surface Impoundment Closure Guidelines for Protection of
Groundwater to Duke Energy instructing the Company to submit the ESSP to NC DEQ
as part of the site’s excavation plan. In accordance with this directive, a copy of the
ESSP is attached as Exhibit “A” to this Plan.
Ash Basin System
The ash basin system was an integral part of the station’s NPDES permitted wastewater
treatment system, which predominantly received inflows from the ash removal system,
station yard drain sump, and stormwater flows. During station operations, inflows to the
ash basin were highly variable due to the cyclical nature of station operations. The
current ash basin system consists of a Primary Ash Basin and a Secondary Ash Basin,
which are separated by an intermediate dam. For the purpose of stormwater
management, the Ash Stack is also within the ash basin system.
The ash basin system is located approximately 2,400 feet to the northeast of the power
plant, adjacent to the Catawba River. The Primary Ash Basin is impounded by an
earthen embankment dam, referred to as Primary Dam (GASTO-97), located on the
west side of the Primary Ash Basin. The Secondary Ash Basin is impounded by an

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earthen embankment dam, referred to as Secondary Dam (GASTO-98), located along
the northeast side of the Secondary Ash Basin.
Originally, the ash basin at Riverbend consisted of a single basin commissioned in
1957. It was expanded in 1979 to its current configuration. In 1979, the original single
basin was divided by constructing a divider dam (Intermediate Dam (GASTO-99)) to
form two separate basins (Primary Ash Basin and Secondary Ash Basin). This
modification improved the original basin’s overall ability for suspended solids removal.
The Intermediate Dam was built over sluiced ash to a crest of 730 feet mean sea level
(msl). At the same time, the Secondary Dam crest elevation remained at 720 feet msl.
At present, the Primary Ash Basin and the Secondary Ash Basin are estimated to
contain approximately 2.6 million and 1.0 million tons of CCR, respectively.
The inflows from the ash removal system and the station yard drain sump were directed
through sluice lines into the Primary Ash Basin. The discharge from the Primary Ash
Basin to the Secondary Ash Basin was through a concrete discharge tower located near
the divider dam. The surface area of the Primary Ash Basin is approximately 41 acres
with an approximate maximum basin elevation of 724 feet msl. The surface area of the
Secondary Ash Basin is approximately 28 acres with an approximate maximum basin
elevation of 714 feet msl. The full basin elevation of Mountain Island Lake is
approximately 647 feet msl.
Prior to the station being retired, stormwater and wastewater effluent from other non-
ash-related station flows to the ash basin were discharged in compliance with the
station’s NPDES permit to the Catawba River through a concrete discharge tower
located in the Secondary Ash Basin. The concrete discharge tower drained through a
30-inch diameter corrugated metal pipe into a concrete-lined channel. The channel
extends from the Secondary Ash Basin to an NPDES Outfall #002 that discharged to
the Catawba River. This discharge pipe has been grouted closed.
Ash Stack
An ash fill deposit, known as the “Ash Stack,” was constructed from ash removed from
the Primary and Secondary Ash Basins during basin clean-out projects. The Ash Stack
was utilized for periodic ash basin clean-outs to prolong the life of the ash basins. The
Ash Stack is a 29-acre area located south of the Primary Ash Basin and contained
approximately 1.4 million tons of CCR. The Ash Stack was constructed during two ash
basin clean-outs; the last recorded ash basin clean-out project was in 2007. Prior to
Phase I excavation, the Ash Stack had a 1.5 to 2 feet of soil cover and vegetation that
was maintained following the last deposition in this area. For the purpose of water
management, the stormwater run-off from the Ash Stack area is routed to the ash basin
system.
Cinder Pit and Other Identified Ash Storage Areas

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Prior to construction of the ash basin, bottom ash (cinders) was deposited in a primarily
dry condition in the “Cinder Pit” and other areas near the cinder pit and coal pile. The
Cinder Pit is approximately 13 acres and is located in a triangular area northeast of the
coal pile and northwest of the rail spur. This area was utilized for storage of ash
material at the station prior to the installation of precipitators and a wet sluicing system.
The Cinder Pit contains predominantly dry cinders and is currently covered with dense
vegetation. The Cinder Pit contains approximately 203,000 tons of CCR.
III. Project Charter
Dewatering of the ash basins and the removal of ash from the site will be performed
within project phases. Required permits for each phase are set forth in Section IX of
this Plan. Phase I included the initial removal of ash from the Ash Stack and basins,
bulk dewatering, decanting of the Primary Ash Basin, and completing any other
subsequent permitted activities.
A dewatering plan for the ash basins has been completed and contracts have been
issued to implement the dewatering plan. Duke Energy submitted an application to
modify its NPDES W astewater Permit to include controls to be implemented during
dewatering activities, and the modified permit became effective on December 1, 2016.
Bulk decanting of the Secondary Basin started early in 2016 and continued under the
permission of NC DEQ and the current NPDES Permit.
As performed during Phase I, the Company will continue to perform the pre-construction
and planning activities for the subsequent phase(s) or work evolutions. These activities
include project planning, development of new ash disposition options, and completion of
additional required permitting that may be necessary for ash removal from the ash
basins and Cinder Pit. Knowledge and opportunities for program improvement obtained
during Phase I of the project are being applied to the subsequent phase(s).
Project Charter O bjective s
Phase II Objectives
1. Excavate and transport ash from the Ash Stack, Cinder Pit, Primary Ash Basin,
and Secondary Ash Basin
2. Validate production rates to meet project requirements
3. Dewater ash basins, pumping water through the on-site waste water treatment
facility
4. Submit and obtain any necessary permits
5. Gain knowledge and opportunities for continuous program improvement

Inactive Ash Areas Objectives

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1. Excavate and transport ash from the Cinder Pit
2. Submit and obtain any necessary permits
3. Gain knowledge and opportunities for program improvement

Project Charter Scope
Phase II Scope
1. Install site erosion and sedimentation control measures, as required
2. Maintain and utilize rail for the transportation of ash from Riverbend
3. Excavate and transport approximately 3.8 million tons of ash from the Ash Stack
and Ash Basins to the approved disposal site
4. Stop water inputs into the ash basins
5. Rerouting of inflows away from the ash basins
6. Operate and maintain the on-site waste water treatment facility to process
contact water to acceptable parameters.
7. Continue dewatering the Primary and Secondary Ash Basins
8. Decommission the Intermediate Dam
9. Plan activities for subsequent work
10. Assess, including delineation, the potential remediation efforts in the Cinder Pit
11. Submit and/or obtain remaining required permit applications for ash removal
activities for subsequent work.
12. Complete closure activities for Primary and Secondary Ash Basins as outlined in
Part II, Sections 3(b) and 3(c), Subparagraphs 1 and 2 of the Coal Ash Act.

Inactive Ash Areas Scope
1. Excavate and transport ash from the Cinder Pit to the appropriate disposal site
2. Cinder Pit closure will be completed as part of overall site closure, but is not
subject to the requirements of Part II, Sections 3(b) and 3(c) of the Coal Ash Act.

IV. Critical Milestone Dates
Critical Milestones within the Plan are summarized in the table below.
MILESTONE NO LATER THAN DATE STATUS
Submit Excavation Plan November 15, 2014 Completed
November 13, 2014
Complete Comprehensive
Engineering review
November 30, 2014 Completed
November 30, 2014
Excavation Plan
Acknowledgement by NC DEQ
February 17, 2015 Completed
February 2, 2015
Receive Industrial Stormwater
(ISW) Permit
March 5, 2015 Completed
May 15, 2015
Commence work – ash removal Final permit approval + 60 Completed

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MILESTONE NO LATER THAN DATE STATUS
Days May 21, 2015
after receipt of ISW Permit
Submit Updated Excavation Plan November 15, 2015 Submitted on November 13,
2015
Submit Updated Excavation Plan December 31, 2016 On track
Submit Updated Excavation Plan December 31, Annually On track
Eliminate stormwater discharge
into impoundments
December 31, 2018 On track
Impoundments closed per Part II,
Sections 3(b) and 3(c) of the Coal
Ash Act
August 1, 2019 On track

V. Erosion and Sedimentation Control Plan
The Erosion and Sedimentation Control (E&SC) plans for the excavation of the Ash
Stack, construction of the rail infrastructure, and haul roads were developed, submitted
to NC DEQ, and approved. Modifications from E&SC plans for subsequent phase(s)
will be approved by NC DEQ prior to installation and initiation of subsequent phase
work.
The approved contractor will install the E&SC measures indicated in the plan. All
control measures will be maintained through the project in accordance with the E&SC
plans. When possible, portions of the E&SC plan will be closed out at the approval of
NC DEQ as areas become stabilized.
VI. Dewatering Plan
The Riverbend ash basins will be dewatered to facilitate the removal of ash and to
mitigate risk. An engineered dewatering plan for Riverbend has been developed, and
interstitial dewatering will begin once bulk dewatering is complete. Riverbend
completed installation of the required water treatment components in the previous
phase of this Ash Plan.
Primary Ash Basin
Remaining water in the Primary Basin is either entrapped in ash or bet ween ash and
soil. That water will be controlled and diverted into a settling basin within the Primary
Basin. Eventually, and when permissible, that water will be pumped to the waste water
treatment facility on site for eventual discharge to the Catawba River, in accordance
with the NPDES permit. The permitted discharge outfall for the waste water treatment
plant is SW002.

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Secondary Ash Basin
The free water in the Secondary Ash Basin will be pumped to the NPDES permitted
discharge Outfall 002 through the waste water treatment facility. The maximum free
water drawdown rate will be one foot over seven days. Following free water removal,
accumulated stormwater will be removed at a maximum rate of two feet over one day.
During excavation of the basin, the Intermediate Dam (GASTO-99) will be
decommissioned and removed, at which time the Primary and Secondary Basins will be
combined. For the combined single basin, the water will be diverted to the settling basin
noted above, then pumped to the waste water treatment plant for treatment prior to
discharge through the permitted outfall.
VII. Location(s) for Removed Ash
The Plan includes the excavation and removal of approximately 3.8 million tons of ash
from the Ash Stack, basins, and Cinder Pit. Ash removed from the site is being
transported by the contractor to permitted facilities. The ash disposal location will be
managed and maintained to ensure environmental compliance with all applicable rules
and regulations.
Phase I: Disposal Sites
A pilot program for ash removal began on May 21, 2015 to transport ash by truck to the
R&B Landfill in Homer, GA. Ash transport to the landfills located at the Marshall Steam
Station in Sherrill’s Ford, NC began on July 27, 2015. Initial ash shipments by truck
from Riverbend to the Brickhaven Structural Fill began on October 23, 2015. Ash
transportation to the R&B Landfill was terminated in September 2015, and ash
transportation to the Marshall Landfill was terminated in the first quarter of 2016. Early
in the first quarter of 2016, rail transport of ash commenced to the Brickhaven Structural
Fill and is expected for the duration of this phase and scope. Eventually, as the
excavation and transportation comes to a close, rail transport may taper off and be
replaced, again, by truck transport before completion.
DISPOSAL SITE LOCATION APPROXIMATE
AMOUNT (TONS)
CCR DISPOSAL
R&B Landfill Homer, GA 15,762 (actual) Landfill
Marshall FGD and Industrial
Landfills
Sherrills Ford, NC 88,745 (actual) Landfill
Brickhaven Structural Fill Moncure, NC 5,074,500 Structural Fill

R&B Landfill

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A total of 15,762 tons of ash has been removed from the site and transported to the
R&B landfill in Homer, GA, which is a permitted facility.

Marshall FGD and Industrial Landfills
The FGD and industrial landfills are located at the Duke Energy Marshall Steam Station
facility in Sherrills Ford, NC. Both are permitted facilities, and 88,745 tons of CCR
material was relocated there.

Brickhaven Structural Fill
The Brickhaven Structural Fill is located at the Brickhaven Mine near the city of
Moncure in Chatham County, NC. It resides on approximately 299 acres. Ash
transported there is beneficially used as structural fill material at the reclaimed mine.
Contingent Plan: Disposal Sites
In the event of any issues with accepting ash at the Brickhaven Structural Fill, the Colon
Structural Fill has been determined as a suitable alternative site.
Colon Structural Fill
The Colon Structural Fill is located at the Colon Mine in Sanford, NC. Ash may be
transported from Riverbend to the Colon Structural Fill to be beneficially used as fill
material for a structural fill project at the reclaimed mine.
The Company continues to develop and evaluate contingency disposal locations in the
event this scenario becomes unobtainable. Contingency plans currently being
developed include assessing alternate ash disposal locations and beneficial use.
VIII. Transportation Plan
Ash will be transported from the site via rail car and/or highway trucks to the off-site
facilities. Transportation will be conducted by approved transporters and will meet
Department of Transportation (DOT) and other applicable federal, state, and local
regulations. Drivers will follow all DOT regulations pertaining to the trucking, including
DOT bridge laws.
Excavation Phases: Transportation
As previously noted in Section VII above, a pilot program for ash removal began with
the transportation of ash by truck to the R&B Landfill in Homer, GA, Marshall Steam
Station landfills, and the Brickhaven Structural Fill. Truck transportation has halted and
been replaced by rail transportation.

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The rail loading system at Riverbend transports ash to the Brickhaven Structural Fill.
The rail system has the ability to load and transport at least 145,000 tons of ash per
month. That system will continue until the very end of the project, when only the
smallest amounts of ash will need to be relocated by truck transportation.

Contingent Plan: Transportation
Trucking will continue to be an option in support of ash transportation by rail.
IX. Environmental and Dam Safety Permitting Plan
Phase I will include initiating excavation and removal of ash from the Ash Stack.
Implementation of Phase I can begin once the permitting for Phase I is in place,
although different permitting may be necessary prior to initiating subsequent phase
work. Permitting activities for subsequent phase(s) will be included in Phase I.
Throughout this project, Duke Energy will continue to seek confirmation that all
necessary approvals have been identified.
Excavation of ash creates potential for stormwater impacts. The facility holds approved
erosion and sedimentation control plans and associated Construction Stormwater
Permits for ash removal. Also, NC DEQ has indicated that an NPDES industrial
stormwater permit is required to transport ash. The Company received the Industrial
Stormwater Permit to support ash removal at the site. Pursuant to the requirements of
the Industrial Stormwater Permit, a stormwater pollution prevention plan (SPPP)
incorporating best management practices has been created and is currently being
implemented. Future modifications to the permit/plan will be managed as necessary.
On February 12, 2016, NC DEQ issued NPDES Permit NC0004961 for operation of the
waste water treatment works at Riverbend and for discharging treated wastewater to the
Catawba River (Mountain Island Lake) and associated tributaries and wetlands. Certain
effluent limits (pH and total hardness) in the permit were subsequently modified under
that certain Special Order By Consent (EMC SOC WQ S16-005) dated November 10,
2016 (SOC).
There are no jurisdictional wetlands/streams associated with the removal of the Ash
Stack or Primary or Secondary Ash basins in Phase I. Future wetland/stream impacts
and jurisdictional determinations will be managed through the U nited States Army Corps
of Engineers with particular attention paid to the difference between jurisdictional
wetlands/streams under Section 404 and those arising from Section 401 waters.
Transfer of the mining permit and receipt of an individual structural fill permit has been
obtained by the mine reclamation project owner/operator to accept the ash.

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Riverbend ash is not classified as a DOT hazardous material.
Subsequent phase(s) will include continued dewatering and continued excavation and
removal of ash from the Ash Stack, Primary and Secondary Ash Basins, and the Cinder
Pit area, although, as discussed in Section III above, the Cinder Pit is not subject to the
requirements of Part II, Sections 3(b) and 3(c) of the Coal Ash Act.
Before shipping ash to a third-party RCRA Subtitle D landfill, waste characterization and
approval will be completed. The necessary Dam Safety approvals will be obtained to
cover activities on or around jurisdictional dams. Breaching of the dams will require
Dam Safety approval. Any impacted wells or piezometers will be abandoned in
accordance with NC DEQ requirements. Fugitive dust will be managed to mitigate
impacts to neighboring areas. Impacts to threatened and endangered species will be
avoided.
No additional site-specific or local requirements have been identified.

Permit Mat rix
MEDIA PERMIT RECEIVED DATE (R)
/ TARGET DATE (T)
COMMENTS
Water
NPDES Industrial
Stormwater Permit
May 15, 2015 (R) Previous Target Date was
March 5, 2015. NC DEQ
issued the ISW permit to the
Company on May 15, 2015.
SPPP implementation date
was November 15, 2015.
NPDES Wastewater
Permit – Major
Modification
First quarter 2016 (R)
(modified by SOC in
fourth quarter 2016)
Previous Target Date was
August 28, 2015. Permit
became effective December 1,
2016.
Jurisdictional Wetland and
Stream Impacts / 404
Permitting and 401 WQC
N/A There are no identified
jurisdictional wetland/stream
impacts.
Dam Safety
Intermediate Dam
Decommissioning
Request Approval
June 16, 2016 (R) Submitted May 31, 2016 and
received approval on June 16,
2016.

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MEDIA PERMIT RECEIVED DATE (R)
/ TARGET DATE (T)
COMMENTS
Primary and Secondary
Dam Decommissioning
Request Approval
June 1, 2017 (T) Transportation and excavation
activities must not impact a
jurisdictional dam or dike.
Excavation activities are
initially staying 50 feet away
from the jurisdictional dike.
Removing ash from the
Primary and Secondary Ash
Basins will have to be
reviewed with Dam Safety.
Breaching of dike will require
Dam Safety approval.
Waste
Individual Structural Fill
Permit

Received Permit to
Operate
October 15, 2015

Mine Reclamation
Owner/Operator obtained an
individual structural fill permit
as set forth in Part II, § 130A-
309.219 of the Coal Ash Act.

Other
Requirements
Site-specific
Nuisance/Noise/Odor/
Other Requirements,
including DOT and FERC
Requirements
N/A None identified.

X. Contracting Strategy
The Ash Management Program strategy is to engage multiple contractors, drive
competition, create system-wide innovation, and develop a collection of best practices.
Duke Energy has engaged contractor(s), who are experienced in coal ash excavation,
transportation, and disposal, and continues to evaluate other potential contractors. The
Company provides in-depth oversight, coordination, and monitoring of the contractors to
ensure the work is performed appropriately. Duke Energy’s core values include safety,
quality, and protection of the environment which are incorporated into our contracts.
The Company continues to evaluate alternate approaches, methods, and contracting
solutions and will adjust its strategy, as necessary.
XI. Environmental, Health, and Safety Plan
Protecting workers, the public, the community , and the environment
Duke Energy is committed to the health, safety, and welfare of employees, contractors,
and the public, and to protecting the environment and natural resources. During all
phases of the project work, Duke Energy and its contractors will follow the Duke Energy
Safe Work Practices Manual, the Environmental, Health, and Safety supplement

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document, and any additional requirements. Occupational health and safety
expectations include oversight and continuous improvement throughout the project.
The project includes comprehensive environmental, health, and safety plans
encompassing all aspects of the project work, including at the plant, in transit, and at the
final destination as needed.
In addition to adhering to all applicable environmental, health, and safety rules and
regulations, Duke Energy and its contractors will focus on ensuring the safety of the
public and protection of the environment during each phase of the project.
XII. Communications Plan
Many different external stakeholders, including neighbors, government officials, and
media have an interest in this project. For example, there is the potential for facility
neighbors and the general public to see or experience construction-related impacts,
such as truck traffic, landscape changes, or noise. The Company is committed to
providing information by proactively communicating about the project activities to
potentially affected parties and responding to inquiries in a timely manner. The project
team has coordinated with Duke Energy’s Corporate Communications Department to
develop and implement a comprehensive external communications plan tailored to the
specific needs of each phase of the project.
XIII. Glossary
TERM DEFINITION
Ash Basin Synonymous with Coal Combustion Residual Impoundment. A
topographic depression, excavation, or dammed area that is
primarily formed from earthen materials; without a base liner
approved for use by Article 9 of Chapter 130A of the North
Carolina General Statutes or rules adopted thereunder for a
combustion products landfill or coal combustion residuals landfill,
industrial landfill, or municipal solid waste landfill; and an area
that is designed to hold accumulated coal combustion residuals
in the form of liquid wastes, wastes containing free liquids, or
sludge, and that is not backfilled or otherwise covered during
periods of deposition.
Ash Stack A dry ash storage feature external to the ash basin
Beneficial Use Projects promoting public health and environmental protection,
offering equivalent success relative to other alternatives, and
preserving natural resources

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TERM DEFINITION
Bottom Ash The agglomerated, angular ash particles formed in pulverized
coal furnaces that are too large to be carried in the flue gases
and collect on the furnace walls. Bottom ash falls through open
grates to an ash hopper at the bottom of the furnace.
Bulk Water Water above the ash contained in the ash basin. Synonymous
with free water
Coal Ash Excavation
Plan
Plan required by NC DEQ letter dated August 13, 2014, including
a schedule for soil and sedimentation erosion control measures,
dewatering, and the proposed location of the removed ash
Coal Ash Management
Act of 2014
North Carolina Session Law 2014-122
Coal Combustion
Residuals (CCR)
Residuals, including fly ash, bottom ash, boiler slag, mill rejects,
and flue gas desulfurization residue produced by a coal-fired
generating unit
Dewatering The act of removing bulk and entrapped water from the ash
basin
Duke Energy Safe Work
Practices Manual
Document detailing the Duke Energy safety guidelines
Entrapped Water Flowable water below the ash surface, which creates hydrostatic
pressure on the dam
Excavation Activities Tasks and work performed related to the planning, engineering ,
and excavation of ash from an ash basin
Excavation Plan Refer to Coal Ash Excavation Plan
Free Water Water above the ash contained in the ash basin. Synonymous
with bulk water
Fly Ash Very fine, powdery material, composed mostly of silica with
nearly all particles spherical in shape, which is a product of
burning finely ground coal in a boiler to produce electricity and is
removed from the plant exhaust gases by air emission control
devices.
NPDES National Pollutant Discharge Elimination System
NPDES Permit A permit that regulates the direct discharge of wastewater to
surface waters

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TERM DEFINITION
Off-Site Facility A structural fill or mine reclamation for the long-term
disposalstorage of coal combustion residuals
Permit Federal, state, county, or local government authorizing document
XIV. Reference Documents
REF DOCUMENT DATE
1 Letter to Duke Energy, Request for Excavation Plans August 13, 2014
2 Coal Ash Management Act of 2014 September 20, 2014

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EXHIBIT A
EXCAVATION SOIL SAMPLING PLAN
RIVERBEND STEAM STATION
ASH BASIN SYSTEM
FOR ASH BASIN EXCAVATION
NORTH CAROLINA ASH BASIN CLOSURE

DUKE ENERGY CAROLINAS, LLC.
526 SOUTH CHURCH STREET/EC13K
CHARLOTTE, NORTH CAROLINA 28202

Waste & Groundwater Programs
Revision 0
December 2016
Excavation Soil Sampling Plan December 2016
Riverbend Steam Station Ash Basin System Revision 0

TABLE OF CONTENTS
SECTION PAGE
1.0 Purpose ............................................................................................................................................ 1
2.0 Soil Sampling methodology ............................................................................................................. 1
2.1 Method Summary 1
2.1.1 Equipment 1
2.1.2 Sample Locations 2
2.1.3 Collection of Representative Samples 2
2.1.4 Sample Preservation, Containers, Handling and Storage 3
2.1.5 Decontamination 4
3.0 Visual Confirmation of Ash Removal ............................................................................................... 4
3.1 Pre-Excavation Documentation 4
3.2 Ash Removal Verification Protocol 4
3.2.1 Field Documentation 5
3.2.2 Fill Evaluation Criteria 5
3.3 Visual Removal Not Applicable 6
4.0 Soil Sampling and Analysis ............................................................................................................... 6
4.1 Soil Sampling 6
4.1.1 Scenario 1 7
4.1.2 Scenario 2 7
4.2 Fate and Transport Modeling 7
5.0 Documentation Summary ................................................................................................................ 8

LIST OF TABLE
Table 1 - Soil Parameters and Analytical Methods

LIST OF FIGURE
Figure 1 - Riverbend Steam Station Sample Grid

Excavation Soil Sampling Plan December 2016
Riverbend Steam Station Ash Basin System Revision 0
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1.0 Purpose
The purpose of this Excavation Soil Sampling Plan is to provide a standardized method for collecting soil
samples at Duke Energy North Carolina ash basins that are to be closed via excavation. Soil samples are
being collected following all visible ash removal from certain ash basins or other ash management units
referenced in Coal Ash Excavation Plans to support closure activities.
This Excavation Soil Sampling Plan is applicable to the collection of representative soil samples. Analysis
of soil samples may be chemical or physical in nature and may be used to determine the following:
 Extent and magnitude of constituent occurrence
 Input concentrations for groundwater fate and transport model
The methodologies discussed in this Excavation Soil Sampling Plan are applicable to the sampling of soil
in ash basin excavation areas. For the purposes of this plan, soils are those mineral and organic
materials remaining after all visible ash has been excavated.
2.0 Soil Sampling Methodology
2.1 Method Summary
This Excavation Soil Sampling Plan has been adapted from Environmental Protection Agency (EPA)
Standard Operating Procedures (SOPs) #2012 and #2006; and North Carolina Department of
Environmental Quality (DEQ) Attachment 1 Coal Combustion Residuals Surface Impoundment Closure
Guidelines for Protection of Groundwater, November 4, 2016.

Soil samples are collected directly using stainless steel or plastic trowel, spade, shovel, or scoops.
Following collection, soil is transferred from the sampling device to a stainless steel or plastic bowl to be
homogenized. Once homogenized, the soil is transferred into Duke Energy Laboratory supplied sample
bottles.
Soil samples will be submitted under chain of custody for the following analyses: total metals and
Synthetic Precipitation Leaching Procedure (SPLP) metals. Analytical methods for total metals and SPLP
metals are described in Table 1. Ash presence is quantitatively determined by polarized light
microscopy (PLM) by RJ Lee Laboratory (or other approved vendor). PLM analysis passes visible light
through a pair of polarizing filters to create optical effects used in identifying unknown materials. This
method is commonly used in asbestos and coal ash identification.
2.1.1 Equipment
 Stainless steel or plastic trowel, scoop, spade or shovel – used for collecting soil samples
from surface locations.
 Sample containers – To be supplied by Duke Energy Laboratory with appropriate
cooler(s). Estimated that 5-8 ounce samples bottles with Teflon-lined lids will be
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required for each sample location and sample depth. For return of cooler to the lab, ice
will be required.
 Gloves – used for personal protection and to prevent cross-contamination of samples –
nitrile, disposable, powderless.
 Field clothing and Personal Protective Equipment – used as specified in the site Health
and Safety Plan.
 Sampling flags – used for identifying soil sampling locations.
 Field notebook – a bound book used to record progress of sampling effort and record
any problems and field observations during sampling.
 Three-ring binder book – used to store necessary forms and record and track samples
collected at the site.
 Permanent marking pen – used to label sample containers, document field logbooks,
data sheets and chain of custody.
 Stainless steel or plastic spoon – used for homogenizing soil samples within a stainless
steel or plastic bowl.
 Stainless steel or plastic bowl – used for homogenizing soil samples, when applicable.
 Camera – used for photo-documentation of sample locations and samples.
 GPS – device used to obtain elevation, latitude and longitude of sample location.
 Trash bag – used to dispose of gloves and any other non-hazardous waste generated
during sampling.
 Decontamination supplies and equipment.
2.1.2 Sample Locations
General locations for soil sampling are determined by the soil scientist in the field at a rate of
one soil sample for every 1 acre of ash basin area excavated. Actual sampling locations on-site
may vary to account for site conditions and to allow collection of representative samples.
Representative samples reflect areas where all ash has been visually excavated and natural soil
is observed.
2.1.3 Collection of Representative Samples
For the purpose of this plan, surface soil is considered to range from 0 to 6 inches in depth while
deeper samples will be collected at a range of 2 to 2.5 feet below ground surface (bgs), 7 to 7.5
feet bgs, 12 to 12.5 feet bgs and 17 to 17.5 feet bgs (unless bedrock, refusal, or the water table
are encountered). A surface soil sample and deeper samples will be collected at each location
for every 1 acre of ash basin excavated. A new pair of nitrile gloves is worn at each sampling
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location and each depth. Each sampling location is recorded on the site map prior to collecting
the sample if location is not already noted on the map. The GPS location of each sampling
location (i.e. elevation, latitude and longitude), sample descriptions, and area photographs are
also recorded. All sampling equipment is decontaminated prior to use irrespective of depth. The
following procedure will be used to collect representative soil samples with a scoop, shovel,
trowel, geoprobe or excavator:
 Locate general sampling locations.
 Determine suitability of sampling location for a representative sample.
 If sampling location appears to reflect representative conditions that would allow
collection of a representative sample, proceed with sampling procedure. If
location is not indicative of conditions that would allow collection of a
representative sample, notify the project manager so an alternate location can
be identified.
 Using a decontaminated sampling instrument, remove the desired thickness and
volume of soil from the sampling area. The sampler must obtain enough soil to
fill five 8-ounce sample bottles.
 Transfer the sample into an appropriate sample or homogenization bowl. Non-
dedicated containers should be adequately decontaminated. Stir for
approximately one minute until there appears to be a uniform color and
consistency.
 Transfer homogenized sample to a labeled container(s) of appropriate size and
construction for the analyses requested.
 Secure sample container tightly.
2.1.4 Sample Preservation, Containers, Handling and Storage
Chemical preservation of soils is generally not recommended. Cooling to 4oC on wet ice is
usually the best approach, supplemented by the appropriate holding time for the analyses
requested.
The Duke Energy Laboratory will supply the appropriate sample bottles for the collected soil
samples. The sample volume is a function of the analytical requirements and the Duke Energy
Laboratory will ensure the appropriate number of bottles are supplied. Ensure chain of custody
is completed for sample bottle return to the Duke Energy Laboratory.
Table 1 contains a list of parameters to be analyzed with corresponding reporting units and
analytical methods. If a parameter or group of parameters is not included in Table 1, the
laboratory performing the analysis should be contacted to determine the appropriate sample
bottles, volumes, and preservatives.
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All non-dedicated sampling devices should be decontaminated and wrapped in plastic. The
sampling device should remain in this wrapping until it is needed. Each sampling device should
be used for only one sample and then decontaminated or disposed of. Non dedicated sampling
devices should be cleaned in the field using the decontamination procedure described below.
2.1.5 Decontamination
Decontamination procedures can be time consuming; having a sufficient quantity of sampling
tools available is recommended. All non-dedicated sampling equipment must be
decontaminated prior to reuse. Equipment decontamination consists of:
1. Detergent wash and brush cleaning
2. Tap water rinse
3. Deionized water rinse
4. Air dry
5. Wrap sampling tools with plastic
3.0 Visual Confirmation of Ash Removal
3.1 Pre-Excavation Documentation
Closure by removal is defined herein as removing the primary source (primary source of potential
constituents of interest) to the point that ash is not visible to the unaided eye at the ground surface.
Primary source ash is the main body of ash that was deposited in the basin. This method is intended
solely to verify and document primary source ash removal and is not intended to validate environmental
quality standards of the subsurface (considered the secondary source of potential constituents of
interest). Pre-excavation documentation would consist of:

 Review topographic mapping, aerial photography, construction drawings, and boring logs to
estimate the pre-ash placement topography and/or ash/soil interface

 Preparation of an ash basin figure illustrating a grid spacing of 100 feet (Figure 1). Each grid
point (node) will be assigned a unique identifier. Each node of the grid spacing (grid point) will
represent a visual verification location.

3.2 Ash Removal Verification Protocol
Ash excavation will be considered complete based on visual confirmation that all ash has been removed.
Ash removal will be based on sampling of the ash/soil interface and analysis by PLM. Soil samples will
be examined utilizing methods outlined in American Society for Testing and Materials (ASTM) D2488,
Standard Practice for Description and Identification of Soils (Visual-Manual Procedure). Vertical and
horizontal excavation of ash can terminate when the remaining material can be documented using PLM
to contain less than 50% ash.

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Project will excavate ash until a visible change in color or texture confirms removal. This location shall
be referred to as the ash/soil interface. If visual evaluation is inconclusive, then request additional
evaluation to confirm ash removal.

3.2.1 Field Documentation
Evaluate the excavated surface elevation relative to the pre-ash placement topography.
Periodically check bottom elevation to evaluate if fill is present above historic bottom elevation.
Visual confirmation will be performed on a 100 foot grid system (Figure 1) unless conditions
prevent such confirmation, as described in Section 3.3. Soil sampling will be performed on an
acre grid system and will be analyzed using PLM.

 Personnel will locate each node by GPS or survey control, determine elevation and
evaluate whether that point is above or below the historic bottom elevation.

 Personnel will then observe the surface area represented by the node to note if visible
ash is present at the surface. If present, the location should be documented and
excavation will need to continue. If the evaluation indicates the surface soils are
residuum or bedrock, then hand auger to two feet below surface (or refusal) and
perform visual-manual classification of the soils at the surface and depth according to
ASTM method D2488. Submit sample from surface and depth (or shallower if refusal)
for PLM analysis. The conditions shall be documented by taking photographs.

 The classification indicator for fly ash will be grey to black silt-sized particles with no
plasticity. The classification indicator for bottom ash will be grey to black sand to gravel
sized particles and porous. If the material cannot be positively identified as soil, submit
a sample for PLM analysis.

 If the node point elevation is near the historic bottom elevation and either (1) residuum
is indicated by observation or (2) soil is confirmed by visual manual classification (ASTM
D2488) and PLM analysis is less than 50%, then personnel can conclude the primary
source is removed.

3.2.2 Fill Evaluation Criteria
The following procedure provides an approach that can be used to ascertain if the fill can remain
in place. The procedure specified is based on the fill material and depth.

 If the elevation is less than eight feet above the historic bottom elevation and residuum
is not observed, then test pits may be excavated to historic bottom elevation or until
residuum or bedrock is encountered but no more than eight feet below the surface.
o Personnel will evaluate existing information to determine if the test pits are
necessary. If necessary personnel may recommend excavating test pits at a
frequency no tighter than 100 feet by 100 feet.
o If visible ash is not discovered based on information defined above, then the
primary source removal may be confirmed.
o If visible ash is discovered, then continue excavation.

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 If the elevation is more than eight feet above historic bottom elevation and residuum is
not observed, discuss with CCP Closure Personnel.
o CCP Closure Personnel will confirm historic information and recommend a
drilling and sampling program at a frequency no tighter than 100 feet by 100
feet to evaluate the presence of ash below the fill in accordance with the
information defined above. If unusual features are revealed by the drilling, CCP
Closure Engineering may request/recommend additional borings. Exploration is
to be performed by continuous sampling during drilling.
o If visible ash is not discovered based on information defined above, then the
primary source removal may be confirmed.
o If visible ash is discovered, then continue excavation.

3.3 Visual Removal Not Applicable
If possible, excavation of ash should continue even if groundwater is encountered. Visual
documentation cannot be completed where ash is under the water table. If Duke Energy cannot
complete visual removal because of site conditions or other restricting factors, documentation shall be
presented to DEQ.

Duke Energy anticipates that in locations where visual documentation cannot be completed, additional
ash characterization along with groundwater fate and transport modeling will be completed. Ash
characterization may consist of SPLP and/or other testing with results imputed into an updated site wide
groundwater fate and transport model. Details will be provided to DEQ for review and concurrence.

4.0 Soil Sampling and Analysis
4.1 Soil Sampling
Soil sampling of the remaining soils (less than 50% ash per PLM analysis) will be necessary to evaluate
the extent of potential secondary source depending on the depth of the water table and any proposed
institutional or engineering controls that may be used in the area of excavation. Soil sampling will not
be required if refusal or the top of bedrock are encountered or the remaining soils are below the water
table. Soil samples for laboratory analysis must be collected in a manner that will ensure a relatively
uniform distribution of particles throughout the six inch sample.
The systematic approach and design for soil sampling an analysis is dependent upon two scenarios:
 Scenario 1: Remaining soil (containing less than 50% ash per PLM analysis) is located above the
seasonal high water table and final constructed institutional and/or engineering controls will
restrict infiltration from the surface reaching the water table (e.g. installation of a liner system).

 Scenario 2: Remaining soil (containing less than 50% ash per PLM analysis) is located above the
seasonal high water table and infiltration from the surface would continue to reach the water
table.

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4.1.1 Scenario 1
Confirmation sampling will include discrete surface samples collected from the first six inches of
the soil. Sampling will be performed on an acre grid system. This sample collection
methodology shall be sufficient to characterize the horizontal extent of any remaining potential
secondary source impacts for comparison with the DEQ Preliminary Soil Remediation Goals
(PSRG). The samples shall be analyzed by a North Carolina certified laboratory for total
concentrations for the following parameters: antimony, aluminum, arsenic, barium, beryllium,
boron, cadmium, calcium, chloride, chromium (total and hexavalent), cobalt, copper, iron, lead,
magnesium, manganese, mercury, molybdenum, nickel, nitrate as nitrogen, pH, potassium,
selenium, silver, sodium, strontium, sulfate, thallium, vanadium and zinc. No SPLP testing is
required.

4.1.2 Scenario 2
Confirmation sampling will include collection of both discrete surface and subsurface soil
samples performed on an acre grid system. Discrete surface samples will be collected from the
first six inches of the soil and a subsurface soil sample will be collected at 2 to 2.5 feet below
ground surface (bgs), 7 to 7.5 feet bgs, 12 to 12.5 feet bgs and 17 to 17.5 feet bgs unless refusal,
bedrock or the water table are encountered. The use of a geoprobe or excavator is anticipated.
This sample collection methodology shall be sufficient to characterize both the horizontal and
vertical extent of any remaining potential secondary source impacts for comparison with the
DEQ PSRGs and/or input into the soil leachate model. The samples shall be analyzed by a North
Carolina certified laboratory for both total concentrations and SPLP for the following
parameters: antimony, aluminum, arsenic, barium, beryllium, boron, cadmium, calcium,
chloride, chromium (total and hexavalent), cobalt, copper, iron, lead, magnesium, manganese,
mercury, molybdenum, nickel, nitrate as nitrogen, pH, potassium, selenium, silver, sodium,
strontium, sulfate, thallium, vanadium and zinc.

4.2 Fate and Transport Modeling
Contingency for stabilization of remaining amounts of potential secondary source impacts in a manner
that will meet the intent of North Carolina Groundwater 2L Rules and closure requirements shall be
considered as site conditions dictate. Provisions to develop groundwater flow and transport models to
evaluate protection of groundwater criteria if some secondary source impacts are left in place shall be
considered. In addition, the possibility of metals leaching from a potential change in pH and
geochemical conditions related to dewatering and excavation shall be considered along with plans for
groundwater models to assess resulting site conditions.

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5.0 Documentation Summary
100’ x 100’ Grid Node (Figure 1) Visually confirm primary source removal and document with
photographs

Soil Sample Collection at a Grid Node (1 per Acre)
Depth/Test PLM Total Metals (Table 1) SPLP (Table 1)
0 – 6 inches X X X
2’ – 2.5’ X X X
7’ – 7.5’ N/A X X
12’ – 12.5’ N/A X X
17’ – 17.5’ N/A X X

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Table
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TABLE 1
SOIL PARAMETERS AND ANALYTICAL METHODS
TOTALS AND SPLP ANALYSIS
NORTH CAROLINA ASH BASINS TO BE CLOSED
VIA EXCAVATION

INORGANIC COMPOUNDS UNITS METHOD1
Aluminum mg/kg or µg/l EPA 6010D
Antimony mg/kg or µg/l EPA 6020B
Arsenic mg/kg or µg/l EPA 6020B
Barium mg/kg or µg/l EPA 6010D
Beryllium mg/kg or µg/l EPA 6020B
Boron mg/kg or µg/l EPA 6010D
Cadmium mg/kg or µg/l EPA 6020B
Calcium mg/kg or µg/l EPA 6010D
Chloride mg/kg or µg/l EPA 9056A
Chromium mg/kg or µg/l EPA 6010D
Cobalt mg/kg or µg/l EPA 6020B
Copper mg/kg or µg/l EPA 6010D
Hexavalent Chromium mg/kg or µg/l EPA Method
7199/218.7
Iron mg/kg or µg/l EPA 6010D
Lead mg/kg or µg/l EPA 6020B
Magnesium mg/kg or µg/l EPA 6010D
Manganese mg/kg or µg/l EPA 6010D
Mercury mg/kg or µg/l EPA Method
7470A/7471B
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Molybdenum mg/kg or µg/l EPA 6010D
Nickel mg/kg or µg/l EPA 6010D
Nitrate as Nitrogen mg/kg or µg/l EPA 9056A
pH SU EPA 9045D
Potassium mg/kg or µg/l EPA 6010D
Selenium mg/kg or µg/l EPA 6020B
Silver mg/kg or µg/l EPA 6020B
Sodium mg/kg or µg/l EPA 6010D
Strontium mg/kg or µg/l EPA 6010D
Sulfate mg/kg or µg/l EPA 9056A
Thallium (low level) (SPLP Extract only) mg/kg or µg/l EPA 6020B
Vanadium mg/kg or µg/l EPA 6020B
Zinc mg/kg or µg/l EPA 6010D
Notes:

1. Soil samples to be analyzed for Total Inorganics using USEPA Methods 6010/6020 and pH
using USEPA Method 9045, as noted above (or similar approved methods). Soil samples will
also be analyzed for leaching potential using SPLP Extraction Method 1312 in conjunction with
USEPA Methods 6010/6020 (or similar approved methods).

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Figure

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Figure 1 – Riverbend Steam Station Sample Grid