HomeMy WebLinkAboutClosure Documentation_20200313DUKE Paul Draovitch
Senior Vice President
ENERGY Environmental, Health & Safety
® RECEIVED and Operations Support
526 S. Church Street
MAR 17 20�� Mail Code: EC3XP
Charlotte, NC 28202
(980) 373-0408
NC DEQUDWR
March 11, 2020
Central office
Rick Bolich, L.G.
North Carolina Department of Environmental Quality
Division of Water Resources
512 North Salisbury Street
Raleigh, NC 27699
Edward F. Mussler III, P.E.
North Carolina Department of Environmental Quality
Division of Waste Management
217 W Jones Street
Raleigh, NC 27603
C Dept of Environmev Quality
N
t4NR i 3 2020
galeigb�egional Office
Subject: Documentation of Compliance with the Coal Ash Management Act of 2014,
Session Law 2014-122, Sections 3.(b), 3.(c)(1) and 3.(c)(2), Coal Ash Impoundment
Excavation and Closure, Riverbend Steam Station — Ash Basin 1 and Ash Basin 2
Dear Messrs. Bolich and Mussler:
This letter responds to the department's letter of December 6, 2019, requesting additional
information around closure of the CCR surface impoundments at Duke Energy's Riverbend Steam
Station (Riverbend). As a preliminary matter, consistent with Duke Energy's earlier position, with
one exception (discussed below), the high -priority sites, including Riverbend, are strictly governed
by Sections 3.(b) and 3.(c) of CAMA. Accordingly, Section 3.(a) of CAMA, which contains,
among other provisions, § 130A-309.213 (impoundment prioritization) and § 130A-309.214
(impoundment closure), is not generally applicable to these sites. The "notwithstanding" language
in the first sentence of Section 3.(b) makes this clear.' The one exception is the applicability of §
130A-309.211, which addresses corrective action to restore groundwater quality.2 The reason for its
applicability to the high -priority sites is explained by the fact that § 130A-309.211 is specifically
referenced in CAMA Section 3.(c)(3). (Indeed, it is the only provision in CAMA Section 3.(a) that
Sections 3.(b) and 3.(c) reference.) This notwithstanding, in recognition of the importance of
providing the department with information it deems relevant to basin closure, Duke Energy provides
the following response:
1 North Carolina General Statutes (N.C.G.S.) Sections 13oA-309.211 and 13oA-309.212 were codified as §§
13oA-309.213 and 13oA-309.214, respectively.
2 N.C.G.S. § 3.(c)(3) refers to "corrective action to restore groundwater quality ... as provided in G.S.13oA-
309-204." The General Assembly probably intended to reference N.C.G.S. § 130A-309-204, which was
subsequently codified as N.C.G.S. § 13oA-309-211. This section was subsequently correctly referenced as
N.C.G.S. § 13oA-309-211 in § 3.(b) of H.B. 630.
Summary of closure activities to date and those planned in the context of proiect
milestones
MILESTONE
STATUS
Submit Excavation Plan to NCDEQ
Completed November 13, 2014
Complete Comprehensive Engineering
Completed November 30,
review
2014
Excavation Plan Acknowledgement from NCDEQ
Completed February 2,
2015
Receive Industrial Stormwater Permit
Completed May 15,
2015
Completed May 21,
Commence Work — Ash Removal
2015
Submit Updated Excavation Plan to NCDEQ
Completed November 13,
2015
Submit Updated Excavation Plan to NCDEQ
Completed December 21, 2016
Submit Updated Excavation Plan to NCDEQ
Completed December 1,
2017
Submit Final Excavation Plan to NCDEQ
Completed December 11, 2018
Eliminate Stormwater Discharge into
Completed December 14,
Impoundments
2018
Impoundments Closed Pursuant to Sections 3.(b)
Completed March 16, 2019
and 3.(c) of CAMA
As -built drawings and schematics along with the results of anv engineering
evaluations and analyses for the closed impoundments
The "as -built" condition of the Riverbend CCR surface impoundments following
excavation of all CCR materials is illustrated in Attachment 1, Bottom of Ash Excavation
Grades. Engineering and analysis was provided in the Ash Removal Verification Report
submitted to the department on April 18, 2019.
Final Plans for management of wastewater and stormwater
Upon the completion of CCR removal from the Riverbend CCR impoundments,
wastewater strearns ceased and the NPDES Wastewater Outfall 002 was decommissioned.
The site is in the final phases of dam decommissioning and grading in general accordance
with Attachment 2, Final Grading Plans. This final grading plan designates sheet flow of
all stol-inwater.
List of all State or Federal permits obtained or anticipated for impoundment
closure
MEDIA1
DATE
COMMENTS
NPDES Industrial
NCDEQ issued the ISW permit
Stormwater (ISW)
May 15, 2015
May 15, 2015. SPPP
Permit
implementation date
Water
was November 15, 2015.
NPDES Wastewater
Q1 2016
Permit became effective December
Permit — Major
(Modified by SOC in
1, 2016.
Modification
Q4 2016)
There are no identified
Jurisdictional
Wetland and Stream
Impacts / 404
N/A
jurisdictional
Permitting
wetland stream impacts.
and 401 W C
Intermediate Dam
Submitted May 31, 2016.
Decommissioning
June 16, 2016
Received approval June 16, 2016.
Request Approval
Decommissioning completed
March 13, 2017.
Primary Dam
Submitted May 8, 2017.
Modification Request
August 3, 2017
Received approval August 3, 2017.
Dam Safety
Approval
Modification completed March 3,
2018.
Resubmitted May 29, 2018.
Primary and
Secondary Dam
Received approval June 7, 2018.
Decommissioning
June 7, 2018
Decommissioning is currently in
Request Approval
progress.
Mine reclamation
Waste
Individual Structural
October 15, 2015
owner/operator obtained
Fill Permit
(Permit to Operate)
an Individual Structural Fill Permit
pursuant to N.C.G.S. § 130A-
309.219.
Original permit received
Duke Energy
Water Conveyance
August 2, 2016
April 7, 2016. Amended permit
Lake Services
Permit
for revised quantities received
August 2, 2016.
Description of the Post -Closure Monitoring and Care Plan; proposed Final
Monitoring Plan
Upon completion of closure and final grading at Riverbend, post -closure monitoring and
care will be conducted in accordance with the June 30, 2016 Post -Closure Operations
Maintenance and Monitoring Plan. This plan was prepared in accordance with N.C.G.S. §
130A-309.212(4)(k) and is included in this submittal as Attachment 3. Groundwater
monitoring will continue to be conducted according to the March 20, 2019 Interim
Monitoring Plan (IMP) until the 2020 IMP is approved by NCDEQ. The current Riverbend
IMP is included in this submittal as Attachment 4. The IMP will be effective at Riverbend
until a site Corrective Action Plan with an associated Effectiveness Monitoring Plan (EMP)
is approved by NCDEQ. Upon the completion of groundwater corrective action,
effectiveness groundwater monitoring will be replaced with post -closure groundwater
monitoring.
Updated cost estimates for closure andpost-closure operation
• Basin closure (including dam stability/emergent projects) ;::� $412.2 million
• EHS-GW/Post-Closure Maintenance - $21.5 million
• Total Compliance Cost --zf $433.7 million
Duke Energy remains committed to safely and permanently closing ash basins in ways that
continue to protect people and the environment and welcomes the opportunity to work
constructively with the department to move forward.
Sincer
Dy,
Pov
Senior Vice
Enviromnent.al, Health & Safety and Operations Support
Attachments:
• Attachment 1, Riverbend Bottom of Ash Excavation Grades
• Attachment 2, Riverbend Final Grading Plan
• Attachment 3, Riverbend Post -Closure Operations Maintenance and Monitoring Plan
• Attachment 4, Riverbend Interim Monitoring Plan Optimization
Attachment 1
Riverbend Bottom of Ash Excavation Grades
RECEIVED
MAR 17 2020
NC DEQ/DWR
Central Office
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Attachment 2
Riverbend Final Grading Plan
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Attachment 3
Riverbend Post -Closure Operations Maintenance and
Monitoring Plan
RECEIVED
MAR 17 2020
NC DEQ/DWR
Centre! Office
POST -CLOSURE OPERATIONS
MAINTENANCE AND MONITORING (OM&M)
PLAN
RIVERBEND ASH BASINS
DUKE ENERGY - RIVERBEND STEAM STATION
MT. HOLLY, NORTH CAROLINA
REVISION 0
Prepared for
DUKE
ENERGY.
Duke Energy
550 South Tryon Street
Charlotte, North Carolina 28202
June 30, 2016
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TABLE OF CONTENTS
1. INTRODUCTION...................................................................................................................................1
1.1 Project Information ........................................................................................................................1
2. DESCRIPTION OF CLOSURE COMPONENTS...................................................................................1
2.1 Compacted Fill.............................................................................................................................. 2
2.2 Geotextiles.................................................................................................................................... 2
2.3 Riprap and Aggregate................................................................................................................... 2
2.4 Final Soil Layer.............................................................................................................................. 2
2.5 Vegetative Ground Cover.............................................................................................................. 3
2.6 Stormwater Management System................................................................................................. 3
3. POST -CLOSURE OM&M PLAN........................................................................................................... 3
3.1
Monitoring Activities...................................................................................................................... 3
3.1.1
Groundwater Monitoring............................................................................................................4
3.1.2
Surface Water Monitoring..........................................................................................................4
3.1.3
Reporting...................................................................................................................................
4
3.1.4
Modifying Monitoring Requirements..........................................................................................5
3.2
Maintenance Activities..................................................................................................................
5
3.2.1
Post -Closure Stormwater Maintenance....................................................................................
5
3.2.2
Post -Closure Erosion and Sediment Control Maintenance.......................................................
5
3.2.3
Post -Closure Vegetation Maintenance......................................................................................6
3.3
Facility ContactInformation...........................................................................................................
7
3.4
Post -Closure Planned Use............................................................................................................
8
3.5
Certification...................................................................................................................................
8
List of Appendices
AppendixA Example Post -Closure Monitoring Form
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1. INTRODUCTION
This Post -Closure Operations Maintenance and Monitoring (OM&M) Plan is being submitted as
part of the Riverbend Steam Station Site Analysis and Removal Plan (Removal Plan) which has
been prepared to address removing coal combustion residuals (CCRs) from the site and to
comply with the regulatory requirements of the North Carolina Coal Ash Management Act
(CAMA) for closure of ash basins / surface impoundments. The information contained in this
plan will be used to assist Duke Energy Carolinas, LLC (Duke) in the closure of inactive coal
ash impoundments and the maintenance and monitoring required during the post -closure care
period.
1.1 Project Information
Duke intends to decommission and remove the CCR facilities, specifically the Primary and
Secondary Ash Basins, Dry Ash Stack and Cinder Pit Storage Area, on the property of the
retired Riverbend Steam Station. The primary objective of the Removal Plan is to remove CCR
materials from the site, breach the existing dams that form the ash basins, and to establish final
grades to promote drainage. The CCR materials at the Riverbend Steam Station will be
excavated and removed from the site using conventional excavation equipment and transported
using over -the -road trucks and, eventually, transition to railcar after the initial phases of the
project. Upon establishing final grades, the site will be seeded to establish a vegetative ground
cover per approved grading plan drawings and specifications. In addition to establishing
vegetative ground cover, relatively gentle slopes will be established during final grading to
control runoff velocities. The final long term disposition of the site has not been determined at
this time. The short term disposition of the site will be grading the site to drain, establishing the
vegetative cover, and maintaining the site in an undeveloped state.
2. DESCRIPTION OF CLOSURE COMPONENTS
Decommissioning of the CCR facilities at the Riverbend Steam Station includes breaching the
Primary Ash Basin Dam (State ID GASTO-097), the Secondary Ash Basin Dam (State ID
GASTO-098), and the Intermediate Dam (State ID GASTO-099). Soil removed from the dams
during excavation and grading activities will be stockpiled and, if suitable, used as fill material to
achieve final grades within the excavation limits of the former CCR facilities. The proposed
closure components are described in the following sections of this report. The various
components to be used for the closure of the CCR facilities will consist of the following:
• Compacted fill (including soil materials excavated from onsite) placed on subgrades
• Geotextiles placed according to decommissioning plan specifications
• Riprap and aggregate placed according to decommissioning plan specifications
• Final soil layer placed on final grades
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• Vegetative ground cover including seed, mulch, and soil amendments applied to
prepared soil surfaces on final grades
A temporary soil layer and vegetation will be installed and maintained during the construction
work to manage erosion and sedimentation. Riprap and geotextiles will be utilized in temporary
and permanent stormwater management structures. Aggregate will be utilized for site access
and temporary haul roads during the construction work. Stormwater management structures will
collect surface water runoff according to the decommissioning plan. The final ground cover for
areas disturbed during the dam decommissioning and CCR removal activities will be vegetated
and maintained with grasses.
2.1 Compacted Fill
Compacted fill to be used in the closure of the CCR facilities at Riverbend Steam Station will be
soil from excavation or grading activities. Soil materials used for compacted fill may classify as
sand (SW, SP, SM, SC), silt (ML or MH), or clay (CL or CH) under the unified soil classification
system. Note that any fill classified as peat (PT) or organic silt or clay (OL or OH) shall not be
accepted as compacted fill for the project.
2.2 Geotextiles
Woven and non -woven geotextile fabrics to be used in the closure of the CCR facilities at
Riverbend Steam Station will consist of polypropylene material resistant to biological
degradation and naturally occurring chemicals, alkalis, and acids. Applicable ASTM and
AASHTO standards for geotextile properties as well as delivery, storage, and handling
requirements are provided in the specifications included with the decommissioning plan.
2.3 Riprap and Aggregate
Riprap to be used in the closure of the CCR facilities at Riverbend Steam Station may consist of
imported Class A, B, C and Class 1 and 2 rock from a commercial quarry meeting the
requirements of Section 1042 RIP RAP Materials in the NCDOT "Standard Specifications for
Roads and Structures," 2012 Edition and additional requirements provided in the specifications
included with the decommissioning plan. Note that demolished concrete shall not be accepted
as imported riprap for the project.
2.4 Final Soil Layer
The final soil layer to be used in the closure of the CCR facilities at Riverbend Steam Station will
consist of topsoil stripped from onsite during excavation or grading activities. Topsoil will be
removed from excavation and grading areas and stockpiled for reuse after final grades are
established at the former CCR facilities. The topsoil shall be spread 3 inches thick on final
grades prior to application of seed, mulch, and soil amendments and will be capable of
sustaining vegetation to prevent erosion.
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In the event that adequate quantities of stockpiled topsoil are not available to cover graded
areas, soil preparation will be implemented according to the soil testing report included in the
technical specification of the decommissioning plan. Finished grade surfaces will be prepared to
promote positive drainage and support a grass vegetative cover.
2.5 Vegetative Ground Cover
The vegetative ground cover to be used in the closure of the CCR facilities at Riverbend Steam
Station will consist of permanent and temporary seed mixes, nurse crops, mulch, and soil
amendments. Unless directly superseded by the plans and specifications, preparation of
subgrade and seeding shall be performed in accordance with the requirements of the North
Carolina Department of Environmental Quality (NCDEQ) "Erosion and Sediment Control
Planning and Design Manual' dated May 2013, or latest revision. Prior to seeding, soil surfaces
receiving seed shall be scarified to a depth of two to four inches to aid seed germination and
reduce loss of seed during stormwater runoff events. However, the vegetative soil layer will not
be subjected to compaction requirements.
2.6 Stormwater Management System
The proposed closure of the CCR facilities at the Riverbend Steam Station is designed with a
network of stormwater conveyances accounting for ash basin dam decommissioning, CCR
removal, and final closure conditions. Stormwater that does not come in contact with CCR
materials during the closure will be treated as non -contact water. Non -contact water will be
managed separately from water within the Ash Basins or that contacts CCR materials. Non -
contact water may be used for dust control or other operational purposes during construction.
Upon final closure, stormwater will be directed across vegetated finished grades and into riprap
energy dissipaters before discharging into stormwater culverts and/or wetland areas that
ultimately discharge to the Catawba River and Mountain Island Lake. Final grading plans and
details illustrating the stormwater management system are provided in the decommissioning
plan drawings.
3. POST -CLOSURE OM&M PLAN
The Post -Closure OM&M Plan outlines the operations, monitoring, and maintenance activities
required to be performed during the post -closure care period. During the post -closure period,
the re -graded and vegetated areas of the former CCR facilities at the Riverbend Steam Station
will be monitored and maintained to sustain their integrity and effectiveness until permanent
vegetation is established.
3.1 Monitoring Activities
Post -closure monitoring events will be conducted quarterly for the first two years and semi-
annually thereafter until permanent vegetation is established on the former CCR facilities. Post -
closure monitoring will include a review of the following:
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• The condition of site security features such as gates and/or fencing
• Evidence of erosion, settlement, ruts, burrows and/or other disturbances within the
closure areas
• Type and quality of vegetation within the closure areas
• Evidence of erosion and integrity of stormwater conveyance features
Example forms that may be used to document the monitoring events are included in Appendix
A. The proposed grading profiles and final grades showing the limits of disturbance and
stormwater features are presented in the decommissioning plan. As -built drawings will be
prepared after the dam breach and following completion of the final grades on the former CCR
facilities. The as -built drawings will be used to assist with post -closure monitoring. Completed
post -closure forms will be maintained in the facility operating record.
3.1.1 Groundwater Monitoring
Post -closure groundwater monitoring requirements will be established in the Groundwater
Monitoring Plan, and submitted under separate cover. The Comprehensive Site Assessment
(CSA) Report (HDR, August 2015a) provides an interim groundwater monitoring plan to bridge
the gap between completion of CSA Report activities and implementation of the pending
Groundwater Monitoring Plan and Corrective Action Plan (CAP).
Two comprehensive sampling events and two background -only sampling events were
conducted in 2015. There have been two comprehensive sampling events so far in 2016.
The proposed constituents and parameters for the interim groundwater monitoring plan are
presented in Table 16-1 of the CSA Report, and the proposed sampling locations are presented
in Table 16-2 of the CSA Report. The interim groundwater monitoring plan includes sampling
background wells during the additional interim groundwater sampling event in 2015.
3.1.2 Surface Water Monitoring
Post -closure surface water monitoring will be consistent with the NPDES permits for wastewater
discharges (Permit NC0004961) and stormwater discharges (Permit NCS000549) for the
Riverbend Steam Station. The discharge permits should be consulted for a detailed description
of the parameters and frequency of surface water monitoring required at the site. Following
completion of the closure activities at the Riverbend Steam Station, wastewater and stormwater
discharge NPDES permits will require modification to reflect the discontinuation of certain
discharges. Discontinued discharges include flow from the ash basin and dewatering liquids, as
well as, several stormwater pipes and outfalls that will be removed during construction.
3.1.3 Reporting
In addition to the forms, reporting, and record keeping that will be maintained as part of the
groundwater and surface water monitoring plans, the various notifications, reports, plans, and
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amendments associated with closure and post -closure of the CCR facilities will be placed onto
Duke's CCR web site.
3.1.4 Modifying Monitoring Requirements
A request can be made any time during the post -closure care period to reduce the requirements
for groundwater monitoring provided that sufficient justification exists for the periodic reduction.
The request will explain the reason for reducing monitoring with justification, and be submitted
to NCDEQ for regulatory approval.
3.2 Maintenance Activities
Maintenance activities will be conducted as soon as practical to address items of concern
identified during monitoring events. Maintenance activities will be performed at the frequencies
defined herein and are anticipated to include the following:
• Localized placement of fill to prevent ponding of water caused by settlement, erosion,
ruts, burrows and/or other disturbances
• Mowing vegetation
• Vegetative cover shall be amended and fertilized as needed to maintain healthy
vegetation
• Repair of stormwater conveyance measures
3.2.1 Post -Closure Stormwater Maintenance
Post -closure operations of the former CCR facilities at the Riverbend Steam Station shall not
cause the discharge of a non -point source of pollution to waters of the United States, including
wetlands, that violates any requirements of an area -wide or statewide water quality
management plan that has been approved under Section 208 or 319 of the Clean Water Act, as
amended.
Stormwater drainage features (i.e., diversion ditches, berms, dissipaters, retention ponds,
discharge pipes, etc.) will be inspected at a minimum of twice per year, and within 24 hours of
rainfall events of 0.5 inches or greater until permanent vegetation is established. Any signs of
damage, settlement, clogging, silt buildup, or washouts will be documented during these
inspections. If necessary, repairs to stormwater features will be made as soon as possible
following detection of a problem. Any disturbed areas will be seeded and soil amendments
applied as necessary to establish a healthy vegetative cover.
3.2.2 Post -Closure Erosion and Sediment Control Maintenance
Erosion and sediment control during post -closure operations of the former CCR facilities at the
Riverbend Steam Station will consist of monitoring and repairing stormwater features and
surface erosion as described above. It is anticipated that post -closure erosion control measures
at the site will include:
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• Minimizing ground disturbances to the extent possible while mowing and performing
other maintenance
• Seeding and mulching of disturbed areas commencing as soon as practically possible
• Employing erosion control matting or seeding and mulch on slopes and other erosion
prone areas
• Use of earthen berms, wattles, silt fences, riprap, or equivalent devices down gradient of
disturbed areas, and at intervals along grassed waterways, until such time as permanent
vegetation is established
• Maintaining an adequate vegetative ground cover with a suitable seed mix and soil
amendments
• Placement of riprap at the, inlets and outlets of stormwater pipes
Adequate erosion control measures will be provided to prevent sediment from leaving the site.
Stormwater features and slopes within the former CCR facilities will be periodically checked for
erosion and vegetative quality, fertilized, and mowed. Slopes will be observed for erosion,
cracking, sliding, sloughing, and seepage. Slopes identified as needing maintenance will be
repaired as soon as practical and as appropriate to correct deficiencies. Repair activities may
include re -shaping the slope, filling in low areas, and/or seeding.
3.2.3 Post -Closure Vegetation Maintenance
Vegetation maintenance during post -closure operations of the former CCR facilities at the
Riverbend Steam Station will consist of periodic mowing at a minimum of twice per year, and
other maintenance activities as needed until permanent vegetation is established and, where
necessary, to enable access to stormwater and groundwater monitoring features during the
post -closure period.
Post -closure maintenance may also include applying temporary seeding and installation of
temporary erosion controls as required until a permanent ground cover is established. Post -
closure mulching may be used to stabilize areas where final grade has been reached and/or
vegetation is inadequate. Soil mulch materials may include wood chips, straw, hay, jute matting,
and synthetic fibers. Mulches allow for greater water retention, reduce runoff, and improve soil
moisture and temperature conditions. Mulch will also help retain seeds, fertilizer, and lime when
it is applied. A minimum of 4,000 pounds per acre of straw mulch is typically applied when
establishing permanent seeding areas. Steeper slopes (3:1 horizontal to vertical or steeper)
should be protected with erosion control matting.
Temporary and permanent seeding will be applied as specified in the current Duke Vegetation
Maintenance Implementation Plan (VMIP) using prescribed seasonal seed mixes or over -
seeding mixes. Alternatively, seeding may be applied in accordance with the NCDEQ "Erosion
and Sediment Control Planning and Design Manual' dated May 2013, or latest revision. Typical
seed mix applications for permanent seeding are as follows:
to. N�
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Table 3.1: Permanent Seeding
Fall to Early Spring - September through April
Species
Pounds per Acre
Kentucky 31 Tall Fescue (Festuca arundinacea)
100
I. Rye Grain (Secale cereale)
50
Spring to Summer - May through August
Species
Pounds per Acre
German Millet (Setaria italica)
50
Post -closure application of soil amendments, including fertilizer and lime, may be required to
establish or improve the vegetative ground cover pursuant to soil sampling and testing results.
North Carolina Department of Agriculture soil test(s) may be conducted to assess soil nutrient
requirements. Typical soil amendment applications for permanent seeding are as follows:
Table 3.2: Permanent Seeding Soil Amendments
Soil Amendment Pounds per Acre
Agricultural limestone 4,000
Fertilizer (10-10-10) 1,000
Mulch (straw) 4,000
3.3 Facility Contact Information
Duke will be responsible for post -closure maintenance and monitoring. Correspondence
regarding the Riverbend Ash Basins should be directed to:
Duke Energy Carolinas, LLC
Riverbend Steam Station
175 Steam Plant Rd
Mt. Holly, North Carolina 28120
(704) 263-3200
Station Sponsor for Ash Basins Operations or Environmental Professional
The physical address of the proposed Riverbend Ash Basins is the same as above.
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3.4 Post -Closure Planned Use
The CCR facilities at the Riverbend Steam Station will be vegetated following closure. Site
access to the public will remain restricted through closure and post -closure care periods. The
final long term disposition of the site has not been determined at this time and there are no
current anticipated post -closure uses for the former Ash Basins, Dry Ash Stack, and Cinder Pit
Area. The short term disposition of the site will be grading the site to drain, establishing the
vegetative cover, and maintaining the site in an undeveloped state. Duke Energy will obtain
approval from NCDEQ if a proposed post -closure use is identified.
3.5 Certification
Within 60 days following completion of the post -closure care period, a notification will be
prepared that the post -closure care has been completed. The notification will include the
certification of a qualified professional engineer verifying that the post -closure care has been
completed in accordance with the Removal Plan and the OM&M Plan. The notification will be
placed in the facility Operating Record.
amec
foster
wheeler
A
Amec Foster Wheeler Environment & Infrastructure, Inc. June 30, 2016
Post -Closure Operations Maintenance and Monitoring Plan
Riverbend Steam Station Site Analysis and Removal Plan
Revision 0
APPENDIX A
Example Post -Closure Monitoring Form
Duke Energy - Riverbend Steam Station
DUKEAsh Basin Post -Closure Monitoring Form
Date/Time:
Observation Personnel:
Weather/Temperature:
Question
No
Yes
If yes, location
Description
Corrective Actions
Date Corrected
Recommended
Is there evidence of erosion,
settlement, rutting, or potholes?
Is there evidence of vegetative
cover intrusion (ruts, burrows,
excavation or other disturbance)?
Is there evidence of stressed
vegetation or bare spots?
Is there evidence of erosion or
sedimentation in stormwater
channels, pipes, or other
stormwaterfeatures?
Is there evidence of regular
maintenance not being
performed?
Is there evidence of human
encroachment (trash, fire pits,
tire/footprints)?
General Notes:
1/1
Attachment 4
Riverbend Interim Monitoring Plan Optimization
MAR 17 2020
NC DEG/OkAl _
Central O#li :,
TABLE 1
IMP Optimization
Summary of Analytical Parameters for Newly Installed Wells
(to begin Q12019)
For each of Duke Energy's 14 North Carolina facilities, new wells installed as part of the CAMA program will be
monitored quarterly. Samples from these wells will be analyzed for parameters formerly included as part of the 4th
Quarter 2018 IMP and additional constituents analyzed voluntarily. After four quarterly events, the monitoring
frequency and/or parameter list for the new wells will be re-evaluated with NCDEQ and may be reduced and/or
optimized. A summary of analytical parameters to include under this criteria is provided below.
SUMMARY OF ANALYTICAL PARAMETERS FOR NEWLY INSTALLED WELLS
Minimum CAMA Parameters per Q4 2018 IMP
{Metals are Totals}
Additional Voluntary Parameters
[Dissolved (Q.45 micron filter)]
Aluminum
Mercury
Molybdenum
Aluminum
Antimony
Mercury
Molybdenum
Nickel
Alkalinity (CO3/HCO3)
Antimony
Nickel
Arsenic
Arsenic
Potassium
Barium
Phosphorus
Barium
Radium (226 + 228)
Beryllium
Potassium
Selenium
Silver
Sodium
Beryllium
Selenium
Boron
Boron
Sodium
Cadmium
Cadmium
Strontium
Calcium
Calcium
Sulfate
Chromium
Strontium
Thallium
Chloride
Sulfide
Cobalt
Chromium
Total Dissolved Solids (TDS)
Copper
Vanadium
Cobalt
Thallium
Iron
Zinc
Copper
Total Organic Carbon (TOC)
Lead
Lithium
Magnesium T
Manganese
Hexavalent Chromium
Uranium (233+234+236+238)
Iron
Total Suspended Solids (TSS)
Lead
Vanadium
Magnesium
IZinc
Additional Voluntary Parameters
(Totals)
Manganese
Fluoride Nitrate + Nitrite
Lithium j Phosphorus
Methane*
Additional: Field Water Quaiit . Pararneer5 _
Dissolved Oxygen (DO)
Oxidation -Reduction Potential (ORP)
Redox Potential (Eh)
Turbidity
Temperature
Specific Conductance
pH
* W.H. Weatherspoon Power Plant only
Wells for Quarterly
Monitoring (23)
CPA-15*/D*
CPA-2S*/D*
CPA-3S*/D*
CPA-4S*
CPA-55*/D*
CPA-65*
CPA-7S*/D*
GWA-115/D
GWA-12S/D
GWA-20S
GWA-2BRU
GWA-3SA/D/BR
GWA-9D
M W-60
Table 2.11- Riverbend
Riverbend Steam Station - IMP Optimization
Summary of Wells, Frequency, & Parameters
(to begin Q12019)
Comprehensive Water level Sweep to Occur Semi -Annually
Modification - February 2019
Wells for Send -Annual Monitoringl' (68)
AB-8S/D
BG-1S/DA
_ BGAS/D
BG-5D/BR
GWA-1S/BRU
MW-1S/D
MW-2SA/D
MW-35/D
MW-4S/D
MW-5S/D
GWA-2S/BR
MW-6S
GWA-45/D/BR
GWA-5S/D
MW-75R/D/BRA
MW-8S/I/D
GWA-6S/D
MW-9/9DA/9BRA
GWA-75/D/BR
MW-10
GWA-8S/D
MW-11SR/DR
GWA-9S/BR
GWA-10S/BRU
MW-13
MW-14
GWA-13S3
MW-15/15DA/15BR
GWA-145/D
OB-1(woterievelonly)
GWA-15S/D
OB-2 (water level only)
GWA-20DA/BR
Comprehensive Water
Level Sweeps
(includes wells in Semi -
Annual, Quarterly, and
Discontinued Monitoring
Lists)
GWA-225/D/BRA
Optimized Quarterly & Semi -Annual Parameters for "Non -New Wells"
(Total)
Antimony
Arsenic
Iron
Manganese
Strontium
Aluminum
Alkalinity(CO3/HCO3)
Calcium
Beryllium
Boron
Sulfate
Dissolved Oxygen (DO)
Chromium (total)
Total Dissolved Solids (TDS)
Redox Potential (Eh)
Chromium (hexavalent)
Vanadium
Lithium
Cobalt
Magnesium
Molybdenum
Nickel
Nitrate + Nitrite
Oxidation -Reduction Potential (ORP)
pH
Phosphorus
Potassium
Sodium
Specific Conductance
Temperature
Thallium
Turbidity
Discontinue Sampling
Ils/Water Level Only (
BG-3S/D
BG-4BR
GWA-13D
To Be Re A
GWA-9BRA
GWA-20BRA
GWA-22SA
MW-4SA
AB-SS/D
AB-2S/D
GWA-23S/DA/BR
A = Comprehensive Site Assessment
,is = Constituents of Interest
MA, CoaI Ash Management Act
:DEQ= North Carolina Department of Environmental Quality
ami-Annual monitoring events are scheduled to be performed concurrently with two Quarterly monitoring events per year and will include the wells listed under Quarterly for
:pective events.
ew wells installed as part of the LAMA program will be monitored quarterly. Samples from these wells will he analyzed for parameters formerly included as part of the 4th Quarter
18 IMP and additional constituents analyzed voluntarily (see Table 1). After four quarterly events, the monitoring frequency and/or parameter list for the new wells will be re-
aluated with NCDEQ and maybe reduced and/or optimized. Replacement wells will not be considered "new wells" and will follow the respective monitoring protocol for the well in
rich they replace; however, additional parameters maybe included voluntarily.
WA-13S will be temporarily sampled until replacement well GWA-22SA is installed. After GWA-22SA is installed:
1. Sampling of GWA-13S will be discontinued
2. Semi-annual water level measurements of GWA-13S will continue