HomeMy WebLinkAbout3612_Allen_ModifiedClosurePlan_Rev2_AppendixA_FID1897214_20230731ESTIMATED VOLUME OF CCR
MATERIAL IN IMPOUNDMENT
AECOM
Job
Description
Duke Energy —Allen Closure Project No. 60572629 Sheet 1 of 2
Estimated Volume of CCR Material
in Impoundment
Computed by ANR
Checked by NSF
Date 9/27/19
Date 7/27/23
The purpose of these calculations is to estimate the quantity of the coal combustion residual
(CCR) material located within the Ash Basin at the Duke Energy Allen Steam Station (Allen),
located in Gaston County, North Carolina. These calculations have been developed independent
of past calculations/estimates prepared by others, and the actual volume of CCR within the Ash
Basin will vary from that presented previously. This variability is primarily due to the differences
in data sources/references used in the calculations. These volume estimates will be refined if
more accurate data is collected throughout the design process.
I. APPROACH
CCR Quantity within the Ash Basin
To illustrate the depth of impounded ash, the approximate pre -development topography (see
Figure A-1), which is based on the Duke Energy drawing No. A3350-113 titled "Ash Storage
Basin, General Plan, As Built Topography', dated 11/11/1975, was compared to existing
topography, which is based on topographic survey performed in February 2015, and
bathymetric contours from AMEC Foster Wheeler's Waste Strategy Analysis report, dated
April 2015. This comparison was performed using AutoCAD Civil 3D version 2016 (AutoCAD).
The quantity of CCR material within the AAB and RAB was subsequently calculated, using
AutoCAD Civil 3D, as the volume differential between the pre -development topographic
contours and the existing topographic contours (see Figure A-2) within the Ash Basin Waste
Boundary, except in the RAB landfill and DORS 1 and DORS 2. In these areas, pre -
development topography was compared to base grades underneath the fill areas. This
comparison is shown in Figure A-3.
The overall estimated volume of CCR material within the AAB and RAB was calculated using
AutoCAD as discussed above; however, the data was supplemented with information from
Duke's CCR Inventory Data (dated 6/30/23) and with scaled tonnage data through 6/30/23.
The quantity of CCR material within the RAB and AAB waste boundaries was calculated to be
approximately 16,387,400 cubic yards (CY) or 19,417,800 tons. This includes the unlined
Distribution of Residual Solids (DORS) facilities that were constructed over the west portion
of the RAB.
A break -down of these quantities is presented in the attached Tables 1, 2A, 2B and 2C.
II. CONCLUSION
Based on the calculations described above, the total quantity of CCR material within the Ash
Basin at Allen is estimated to be approximately 16,387,400 CY, or 19,417,800 tons.
AECOM
Job Duke Energy —Allen Closure Project No. 60572629 Sheet 2 of 2
Description Estimated Volume of CCR Material Computed by ANR Date 9/27/19
in Impoundment Checked by NSF Date 7/27/23
III. ATTACHMENTS
Attachment A: Figures
- Figure A-1— Pre -Development Topography
- Figure A-2 — Existing Topography
- Figure A-3 — In -Place CCR Material Isopach Map
Attachment B: Tables
- Table 1— Estimated Volume of CCR Material in Impoundment Subject to Closure
Plan
ATTACHMENT A
Figures
ALLEN STEAM
STATION
REV.
INCHES
TENTHS
1
30
1
PLANT ALLEN RD
--------
- __---'' --''\\
COT
I
I
I
ACTIVE ASH BASIN
575
RETIRED ASH BASIN DIKE
tiOonl C-0
LAKE WYLIE/ CATAWBA
RIVER
LAKE WYLIE/ CATAWBA
RIVER
0 300 600 900
GRAPHIC SCALE (IN FEET)
LEGEND:
HISTORIC MAJOR CONTOUR (25 FOOT)
HISTORIC MINOR CONTOUR (5 FOOT)
LIMITS OF IMPOUNDED ASH
NOTES
1) LIMITS OF IMPOUNDED ASH ARE APPROXIMATE.
2) (5 FT) CONTOURS WERE DIGITIZED FROM HISTORICAL
TOPO BY AMEC AS PART OF THE WASTE STRATEGY
ANALYSIS REPORT DATED APRIL 2015. (FIGURE 2.2).
3) A DATUM SHIFT OF -0.75 FT WAS APPLIED TO CONVERT
ELEVATIONS FROM NCVD29 TO NAVD88.
REFERENCES
1) DRAWING NO. A3350-1 B ENTITLED "ASH STORAGE BASIN,
GENERAL PLAN, AS BUILT TOPOGRAPHY", PREPARED BY
DUKE POWER COMPANY, DATED 11/11/75
TITLE
PRE -DEVELOPMENT TOPOGRAPHY
RETIRED AND ACTIVE ASH BASINS
AAECOM -\LLLIN 5 1 rzrlivi 5 1 A 1 lUIN
4v18 CLOSURE PLAN UPDATES
GASTON COUNTY, NORTH CAROLI
N.C. ENGINEERING LICENSE NO. FOR F-0342 ISSUED r- REVIEW
SEAL SCALE: DES:
DUKE DWG TYPE :. DWG DFTR :
ENEJOB NO: CHKD:
RGY® DATE: ENGR:
FILENAME: Figure A-l.dW APPD:
DWG SIZE DRAWING NO. REVISION
ANSID 22.0"x34.0" FIGURE - A-1
V
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1 1
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0 300 600 900
GRAPHIC SCALE (IN FEET)
LEGEND:
LAKE WYLIE/ CATAWBA EXISTING MAJOR CONTOUR (25 FOOT)
RIVER EXISTING MINOR CONTOUR (5 FOOT)
LIMITS OF IMPOUNDED ASH
BATHYMETRIC MAJOR CONTOUR
(25 FOOT)
BATHYMETRIC MINOR CONTOUR
(5 FOOT)
LIMITS OF BATHYMETRIC
SURVEY
EXISTING TRANSMISSION LINES
,J�, pd ® TRANSMISSION TOWERS / POLES
NOTES
1) LIMITS OF IMPOUNDED ASH ARE APPROXIMATE.
2) AERIAL TOPOGRAPHIC SURVEY WAS
PERFORMED BY WSP IN FEBRUARY 2015.
3) BASIS OF BEARINGS: NC GRID NAD83.
4) ELEVATIONS ARE BASED ON NAVD88.
5) UNDERGROUND UTILITIES ARE NOT SHOWN IN
THIS FIGURE.
6) VOLUME OF FREE WATER, WITHIN THE LIMITS OF
BATHYMETRIC SURVEY SHOWN, IS
APPROXIMATELY 92 MILLION GALLONS.
7) THE VOLUME OF FREE WATER WAS OBTAINED BY
COMPARING THE EXISTING TOPOGRAPHY
SURVEY AND THE BATHYMETRY SURVEY
SURFACES, IN AUTOCAD CIVIL 3D.
REFERENCES
1) BATHYMETRIC SURVEY SHOWN WAS OBTAINED
FROM AMEC'S WASTE STRATEGY ANALYSIS
REPORT DATED APRIL 2015.
TITLE
EXISTING TOPOGRAPHY
RETIRED AND ACTIVE ASH BASINS
P"=com -\LLLIN 5 I LAM 5 I A I WIN
4v18 CLOSURE PLAN UPDATES
GASTON COUNTY, NORTH CAROLINA
LAKE WYLIE/ CATAWBA N.C. ENGINEERING LICENSE NO. FOR F-0342 r r w
RIVER ISSUE REVIEW
SEAL SCALE: DES:
UKE DWG TYPE:.DWG DFTR:
JOB NO: CHKD:
ENERGY® [DATE. ENGR:
FILENAME: Figure A-2.dwg APPD:
DWG SIZE DRAWING NO. REVISION
ANSID 22.0"x34.0" FIGURE - A-2
V
INCHES
TENTHS 10 20
30
10
1
REV. C
ALLEN STEAM n
I� la \ \� �� 1 l \ \ -• V STATION �\
d
ILI-
—/ �—'. -- ' ( ► '\ \tip
Nz
PLANT ALLEN RD
0 300 600 900
I✓
GRAPHIC SCALE(IN FEET) 1 II
�I 2S\�
Lo
RETIRED ASH BASIN DIKE LEGEND:
co
I - ---_ ���
EXISTING MAJOR CONTOUR (25 FOOT)
�✓'\ _- `— �1 / l� I I I I I �^ 1 I LAKE WYLIE/ CATAWBA
RIVER EXISTING MINOR CONTOUR (5 FOOT)
�I
l II L� U� I IIII ✓� ��\�__� tl IIII I
LIMITS OF IMPOUNDED ASH
if
H BASIN RETIRED AS — _ — -_ I I III II I IMPOUNDED ASH
, , �� �I I I
NUMBER DEPTH (FT.) COLOR
l -� I I III I, I II II I II I ,I�I� IIII I I I
�I II Ill II II III I ✓I II II II III 1 10.00
I� I I I
� o � I I � III I � 2 20.00
III I I N I II I 3 30.00
1 � I I �� � I � I �� III I I _ _ __��� — .� ooJ I � I I 4 40.00
�l �- \�I��f�ll IIIII { II ��{- _ ----_— _--� Iillll
/ I \� \ II ►��/� I — _ — _ _ _ — _ I I 5 50.00 NOTES
i -- \ \ \ _ — J ����� I I✓ _ _ _ ,� �_ _ II I) 6 60.00 1) LIMITS OF IMPOUNDED ASH ARE APPROXIMATE.
7 70.00 2) IMPOUNDED ASH VOLUME WAS CALCULATED USING
8 80.00 AUTOCAD CIVIL 3D SOFTWARE.
IKE
NORTH D
9 90.00 3) SURFACES SHOWN ON FIGURES 01 AND 02 (EXISTING
II 10 100.00 TOPOGRAPHY AND PRE -DEVELOPMENT TOPOGRAPHY
RESPECTIVELY) WERE COMPARED TO GET THE
11 110.00 VOLUME AND THICKNESS OF IMPOUNDED ASH.
12 120.00
I l r II / III II II III
�
II0Is ,
r I II I�
�. �
-65
i —
; IIII\
ACTIVE ASH BASIN
� fr �IIII
I��
�
II II Q �
�
�. j1 1 I II III III
TITLE
IMPOUNDED ASH THICKNESS
III I o r�t ll i RETIRED AND ACTIVE ASH BASINS
ALLEN STEAM STATION
2018 CLOSURE PLAN UPDATES
GASTON COUNTY, NORTH CAROLINA
LAKE WYLIE/ CATAWBA FOR ISSUED FOR REVIEW
— — \\\ \ �� \\ 11 RIVER
SCALE: DES: ANR
DWG TYPE:. DWG DFTR: ANR
JOB NO: 60572629 CHKD: JDM
DATE: 1-30-19 ENGR: JDM
FILENAME: Figure A3.dw APPD: JDM
DWG SIZE DRAWING NO. REVISION
ANSI D
22.0"x34.0" FIGURE - A3 C
INCHES 1 2 3 TENTHS 10 20 30 1 5 6 ; 8 1 10
ATTACHMENT B
Tables
Table 1: Estimated Volume of CCR Material in Impoundment Subject to Closure Plan
Allen Station CCR Inventory
CCR unit
tons
CY
Retired Ash Basin (RAB)1
8,395,600
7,593,900
- RAB Area Outside RAB LF Footprint
5,569,660
4,641,400
- RAB Ash under landfill including subgrade
600,000
500,000
- RAB Ash above liner in landfill 2
1,234,740
1,234,740
- DORS 1
428,400
357,000
- DORS 2
562,800
469,000
Active Ash Basin (AAB) 3
11,022,200
9,185,200
GRAND TOTAL
19,417,800
16,387,300
1Future ash production to be placed within the lined RAB Landfill beyond 6/30/23 is excluded.
2CCR material tonnage provided is based on CCR Inventory Data provided by Duke as of 6/30/23. A
conversion factor of 1.2 tons/cy of CCR was assumed, with the exception of ash contained within the
RAB Landfill above the liner, in which case a factor of 1.0 tons/cy was used.
3 Sluicing of CCRs to the AAB ceased on February 9, 2019.