WQ0003468_Report_20220809

Geosyntec l>
consultants
Geosyntec Consultants of NC, P.C.
To Ms. Morella Sanchez King
Wilmington Regional Office
127 Cardinal Drive Extension
Wilmington, NC 27405
[e-mail]
910-796-7218
Subject: West Fraser Armour Mill CLRS Permit WQ0003468
Inspection Comment Responses
Dear Ms. Sanchez King,
2501 Blue Ridge Road, Suite 430
Raleigh, NC 27607
PH 919.870.0576
www.geosyntec.com
August 9, 2022
Geosyntec Consultants of NC, P.C. (Geosyntec) has prepared this letter on behalf of West Fraser,
Inc. (West Fraser) in response to your April 6, 2022, inspections report providing comments on
the closed loop recirculation system (CLRS) Permit WQ0003468 for the Armour Mill Plant in
Riegelwood, North Carolina (Site). During the North Carolina Department of Environmental
Quality (NCDEQ) routine inspection of the Site, NCDEQ noted that several minor modifications
had been made to the CLRS. The four main modifications identified were: (i) the removal of the
centrifuge system; (ii) the replacement of the recirculating pump; (iii) the addition of a new
oil/water separator (OWS); and (iv) modifications to the Ash Pond 2 outlet pipe that supplies the
CLRS recirculation pump. NCDEQ requested that these modifications be documented with a
modification permit application.
On July 14, 2022, Geosyntec and West Fraser met with NCDEQ via teleconference to provide an
update on project status and to discuss potential additional modifications to the CLRS that West
Fraser may implement. Based on the outcome of the phone conversation with NCDEQ on July 14,
2022, a modification permit application, including previous modifications and planned future
modifications, will be submitted at a later date in conjunction with the Site's permit renewal
application. The purpose of this letter is to provide responses to the comments in the inspection
letter. For ease of review, this letter is formatted such that each NCDEQ comment is repeated and
then followed by West Fraser's response to the comment.

Ms. Morella Sanchez King
August 2022
Page 2
NCDEQ Comment No. 1:
Provide a written narrative of activities for which the permit modification is being requested.
Response to NCDEQ Comment No. 1:
A description of each previous modification is included below:
Centrifuge: The Swaco 414 centrifuge dewatering system was installed in 2005 adjacent
to the boiler and scrubber to aid in the separation of ash and water exiting the scrubber. At
the time of installation, it was assumed that both ash ponds would soon close, however, the
ash ponds remained in operation at the Site, eliminating the need for the centrifuge. To
reduce operations and maintenance costs at the Site, the centrifuge was decommissioned
and removed from the Site in 2019.
Recirculation Pump: The Gorman -Rupp Super T Series self -priming centrifugal pump
(Model No. T3A60S-B /F) was installed in December 2021 at the pump house on the west
side of Ash Pond 2. This modification was a like -for -like replacement for the original 500
gallons per minute (gpm) pump which had reached the end of its functional lifetime. The
replacement pump was selected to decrease operations and maintenance efforts and provide
easier functionality for Site personnel.
Oil/Water Separator: A model 6V Oil Skimmers Inc. OWS was installed in August 2021
in the vehicle washdown area. This new separator reduces solids, is more efficient, and
involves easier operations and maintenance than the previous OWS, a Sandpiper PN
S30B1ANNANS700. While the previous OWS is not currently being utilized for
separation of oil and water, it is still being utilized to pump residual water from the vehicle
washdown area into Ash Pond 1. Note that the use of the old OWS to pump water into the
Ash Pond is only employed intermittently as needed at the Site and does not represent a
continuous source of water to the Ash Ponds.
Outlet from Ash Pond 2: A new inlet pipe to the recirculation pump was installed at Ash
Pond 2 in December 2021 to replace the old, damaged pipe. This pipe was modified during
the installation of the new recirculation pump. Previously, the intake was located against
the bottom of Ash Pond 2, which resulted in elevated solids content being introduced into
the recirculation system at the pump suction inlet. The new pipe intake is submerged just
below the surface of the pond to reduce solids; its position relative to the pond surface level
is held in place by an attached buoy.
engineers I scientists I innovators

Ms. Morella Sanchez King
August 2022
Page 3
As discussed above, a modification permit application will be submitted at a later date in
conjunction with the Site's permit renewal application.
NCDEQ Comment No. 2:
Provide a detailed revised process diagram. The process diagram is recommended to:
1. Demonstrate that the system operates as a closed loop system (e.g., that the flow
following the dumpster flows to Pond #1).
2. Depict how all the flows associated with the water softener are directed (e.g., flow into
and out of the unit as well as backwash water);
3. Depict all inlet structures (e.g., surface drop inlets, etc.); and
4. Indicate if potable water for the on -site buildings is provided through the same water
meter or other(s). Indicate the location of the water meter(s) on a site diagram.
Considering the modifications to the system over the years, additional site diagrams are
recommended to depict the location of structures referenced within the process diagram to assist
in a timely review of the permit modification application.
Response to NCDEQ Comment No. 2:
Figure 3 of the Closed Loop Evaluation Report (Attachment A; Geosyntec, 2022) depicts the
process flow diagram of the current system and demonstrates that the system operates as a closed
loop.
Figure 3 also depicts how the inflow, outflow, and backwash flows associated with the water
softener are directed within the system. As illustrated, county water flows into the softener, and
subsequently exits the softener and flows into the boiler. Softener backwash exits the softener and
flows into a collection pit located near the softener. Process water collected in the collection pit
continues to flow through a series of additional collection pits that also receive stormwater.
Ultimately, these collection pits transmit flows to Ash Pond 1.
Figure 2 of the Closed Loop Evaluation Report (Attachment A) depicts the locations of structures
identified in the process flow diagram. The locations of inlets and outlets of the ash ponds and the
location of the county water meter can be found in Figure 2.
engineers I scientists I innovators

Ms. Morella Sanchez King
August 2022
Page 4
County water is provided to the Site through the single meter located at the scrubber as shown on
Figure 2 of the Closed Loop Evaluation Report (Attachment A). The county water meter measures
combined flow for the following on -Site demands: process water, fire water, and potable water.
NCDEQ Comment No. 3:
Request confirmation that system operates as a closed -loop system. This can be accomplished
either through an assessment with a water balance approach or by providing documentation of the
characteristics of the impermeable layer(s) of the settling basins to demonstrate that infiltration is
not occurring.
Response to NCDEQ Comment No. 3:
The Closed Loop Evaluation Report (Attachment A; Geosyntec, 2022) describes activities
completed to assess whether the Site CLRS operates as a closed loop. A water balance was
performed around the ash ponds utilizing a combination of flows measured at the Site, precipitation
data gathered from a local weather station, and transpiration/evapotranspiration estimated using
the Thornthwaite method. Ultimately, the Closed Loop Evaluation Report indicates that the system
operates as a closed loop. Please note that based on the water balance evaluation, West Fraser is
planning additional modifications to the CLRS to decrease uncertainties associated with the closed
loop calculation. As discussed previously, West Fraser will submit a permit modifications package
at a later date. For more details, refer to Attachment A.
engineers I scientists I innovators

Ms. Morella Sanchez King
August 2022
Page 5
CLOSING
We trust that these responses address the comments provided by the NCDEQ. Please feel free to
contact either of the undersigned if there are further comments or questions.
Sincerely,
,,,„„,,,,,49,1„i
Jim Deitsch, Ph.D., P.E. (NC, GA, MA, MD, NC, OH) Hari Parthasarathy, Ph.D., P.E. (sc)
Sr. Principal Engineer Senior Engineer
Attachment A
Closed Loop Evaluation Report, Geosyntec, 2022.
engineers I scientists I innovators

ATTACHMENT A
Closed Loop Evaluation Report

LEI
West Fraser
Prepared for
West Fraser Inc.
361 State Rd 1879
Riegelwood, NC 28456
CLOSED LOOP
EVALUATION REPORT
Armour Mill Plant
Prepared by
Geosyntec D
consultants
Geosyntec Consultants of NC, P.C.
Geosyntec Consultants of NC, P.C.
2501 Blue Ridge Road, Suite 430
Raleigh, North Carolina 27607
Project Number GR8879
August 2022

Geosyntec °
consultants
Geosyntec Consultants of NC, P.C.
TABLE OF CONTENTS
1. Introduction 1
2. Background 2
3. Process Components and Flow 3
4. Closed Loop Evaluation Methods 4
4.1. Water Balance Framework 4
4.2. Flow Rate Data 5
4.2.1. Installation of Flow Meter 5
4.2.2. Collection of Flow Rate Data 6
5. Results 8
5.1. Water Balance 8
5.2. Uncertainties 8
6. Summary 10
7. References 11
Table 1
Table 2
Table 3
Figure 1
Figure 2
Figure 3
LIST OF TABLES
Pipe #1 Flow Meter Data and Flow Analysis
Precipitation Flow Rates into Ash Ponds 1 and 2
Potential Evapotranspiration Flow Rates from Ash Ponds 1 and 2
LIST OF FIGURES
Site Location
Site Diagram
Process Flow Diagram
GR8879/CLRS Evaluation Report_Rev 0 i 08.09.22

1. INTRODUCTION
On behalf of West Fraser, Inc., Geosyntec Consultants of NC, P.C. (Geosyntec) has
prepared this Closed Loop Evaluation Report for the Armour Mill Plant in Riegelwood,
North Carolina (Site). Currently, the facility operates under North Carolina Department
of Environmental Quality (NCDEQ) Permit No. WQ0003468, issued January 9, 2019,
and effective from June 1, 2019, through November 30, 2023. Alterations to processes at
the Site have prompted the need for a permit modification of the Closed Loop Recycle
System (CLRS) in accordance with 15A NCAC 02T .1000 of the North Carolina
Administrative Code (NCAC). NCDEQ performed a routine inspection of the Site and
provided comments on the CLRS on April 6, 2022. This report, and associated figures
and tables, addresses Comments 2 and 3 from the NCDEQ inspection report.
The remainder of this report is organized as follows:
• Section 2 — Background, including Site ownership history and modifications;
• Section 3 — Process Components and Flow, including detailed descriptions of
pertinent equipment;
• Section 4 — Closed Loop Evaluation Methods, including data collection and the
water balance method utilized to assess the closed -loop nature of the Site;
• Section 5 — Results, including the ensuing analysis from the water balance
calculation;
• Section 6 — Summary; and
• Section 7 — References.
GR8879/CLRS Evaluation Report_Rev 0 1 08.09.22

2. BACKGROUND
The Site is located at 361 Federal Road, Riegelwood, Columbus County, North Carolina
(Figure 1). The facility accepts cut logs and produces finished lumber. Wastewater
generated through the lumber processing is treated through settling and managed by the
CLRS.
The Site's permit was first issued on August 9, 1990 to Federal Paper Board Company,
Inc., superseding Permit No. 5402R. In 1995, International Paper Co. (International
Paper) acquired Federal Paper Board Company, Inc. The subsequent permit dated
October 22, 1999 was issued to International Paper. In 2006, International Paper agreed
to sell the Site to West Fraser, Inc.. A request was made to NCDEQ on February 28, 2007
to change the permit holder from International Paper, Wood Products, to West Fraser,
Inc. To date, West Fraser, Inc. continues to operate the Armour Mill Plant.
Over the years, the Site has made changes to the CLRS, including decommissioning of
the centrifuge system, installation of a belt -type oil/water separator (OWS)in the vehicle
washdown area, replacement of the recycle pump, and modifications to the outlet
structure of the ash ponds.
The NCDEQ performed a routine inspection of the Site on April 6, 2022. In their
inspection report, NCDEQ noted that the aforementioned modifications had been made
to the CLRS. Based on the findings of the inspection, NCDEQ informed West Fraser,
Inc. that, due to the changes to the CLRS, a modification to the CLRS permit will likely
be required. The NCDEQ also requested that the Site evaluate whether the system is still
operating as a closed loop. The purpose of this report is to document the water balance
evaluation undertaken to address the NCDEQ's comment about the closed nature of the
CLRS.
GR8879/CLRS Evaluation Report_Rev 0 2 08.09.22

3. PROCESS COMPONENTS AND FLOW
This section provides a comprehensive overview of the CLRS to better understand the
equipment and flow rates associated with this system. Figure 2 depicts the locations of
inlets and outlets of the ash ponds, the location of the county water meter, and the
locations of other relevant structures. A process flow diagram illustrating this process is
shown in Figure 3.
County water provides water for the vehicle wash down area and a Culligan CSM Duplex
alternating flow water softener. The softener prepares water for entry into a wood -fired
boiler with a maximum heat input of 104,336 British thermal units (BTU)/hour. The
boiler produces steam to power two continuous kilns (drying rate of 137,415 thousand
board -feet [MBF] of lumber per year) and one batch kiln (drying rate of 20,000 MBF of
lumber per year) used to dry lumber. Ash produced from the boiler enters a multicyclone
and venturi wet scrubber with a capacity of 350 gallons per minute (gpm). The scrubber
collects ash directly from the boiler and separates the ash from the boiler exhaust using
water from a 13,000-gallon makeup tank. Backwash from the softener, blowdown from
the boiler, overflow from the makeup tank, water from the kilns, and blowdown from the
scrubber enter a centralized system of collection pits. Water from these processes, as well
as stormwater in the vicinity of the collection system, enters the collection pits and
ultimately flows into two 0.167-million-gallon ash ponds. The purpose of the ash ponds
is to provide hydraulic residence time for ash settling. Water enters Ash Pond 1 from the
collection pits and then overflow water from Ash Pond 1 is gravity fed to Ash Pond 2
through a connecting pipe. A self -priming centrifugal recirculation pump (Super T Series
Gorman Rupp Model T3A60S-B/F) pumps water from Ash Pond 2 to the makeup tank
where it is held and ultimately reused by the scrubber.
Simultaneously, the vehicle wash down area that is used to clean vehicles and other
equipment contains an OWS and an additional pump that transmits wastewater to Ash
Pond 1 through a second inlet pipe. A standalone OWS (Oil Skimmers Inc. Model 6V)
removes oil from washdown water. The old OWS machinery (Sandpiper PN
S30B1ANNANS700) is still in use in the vehicle wash down station, though it is no
longer used for separation. Instead, the pump is used to transport the skimmed wastewater
from the wash down area to Ash Pond 1. The new OWS operates intermittently on an as
needed basis at low flow rates and does not represent a source of continuous flow to the
ash ponds.
GR8879/CLRS Evaluation Report_Rev 0 3 08.09.22

4. CLOSED LOOP EVALUATION METHODS
4.1. Water Balance Framework
A water balance calculation to evaluate the closed nature of the CLRS was performed as
per NCDEQ 15A NCAC 02T .1004(b)(4). This calculation compares the flows into and
out of the Ash Ponds. The inflows and outflows from the Ash Ponds are outlined below:
Inflows
• Pipe #1: Pipe #1 refers to the final section of process flow pipe before entering
Ash Pond 1 (Figures 2 and 3). Just upstream of the entrance to Ash Pond 1 is a
collection pit, which aggregates a combination of stormwater and process water.
Stormwater is collected from runoff over impervious pavement in and adjacent to
the milling operation of the facility. Process water includes (i) blowdown from
the scrubber and boiler, (ii) backwash from the softener, (iii) overflow from the
makeup tank, and (iv) condensate from the kilns. Flow from the collection pit is
transported through Pipe #1 to Ash Pond 1.
• Pipe #2: Pipe #2 refers to the pipe that connects the vehicle washdown area to Ash
Pond 1 (Figures 2 and 3). The flow entering Pipe #2 is wastewater from the OWS.
This flow rate is minimal and not continuous and calculated to be approximately
0.65% of total inflow at the Site; as such, it is assumed to be negligible for this
water balance calculation.
• Precipitation: Precipitation is collected in Ash Ponds 1 and 2. Stormwater that
falls in the vicinity of the collection pits is diverted into collection pits, which
ultimately flow into Ash Pond 1 through Pipe #1. Therefore, this precipitation
inflow refers only to precipitation that falls directly over the Ash Ponds.
Outflows
• Potential Evapotranspiration (PET): Water exits the system through PET from
Ash Ponds 1 and 2.
• Recirculation Pump: Water from Ash Pond 2 is pumped via the recirculation
pump to the makeup tank. This water is then reused by the CLRS.
GR8879/CLRS Evaluation Report_Rev 0 4 08.09.22

Storage
• The water balance assumes that the water levels of Ash Ponds 1 and 2 do not
fluctuate. This assumption was corroborated by water level data collected by the
water level sensors located in the ash ponds from June 27, 2022, through June 30,
2022. Therefore, there is assumed to be negligible change in the storage capacity
of the ash ponds over the period of this water balance calculation.
4.2. Flow Rate Data
This section describes the field effort of the flow meter installation and how the field data
was processed. It also describes how flow rate data was managed for the water balance
calculation.
4.2.1. Installation of Flow Meter
Geosyntec performed a flow meter installation at the Site from June 27 to 30, 2022. An
ISCO 750 area velocity flow meter, in conjunction with an ISCO 6712 portable sampler,
was used to collect flow rate data for this field event. This flow meter uses Doppler
ultrasonic technology to measure the average velocity of a flow stream and a submerged
pressure transducer to measure depth of the flowing liquid. The level measurement of this
instrument can measure a range of 0.033 to 10 feet, with accuracy within 0.008 feet for
measurements below 5 feet. The average velocity can be measured from ranges of -5 to
20 feet per second (ft/s), with accuracy within 0.1 ft/s for velocities up to 5 ft/s and within
2% of the reading for velocities between 5 and 20 ft/s.
The flow meter was installed on the bottom of the wastewater/stormwater collection pit
just upstream of Pipe #1 to measure the flow rates entering Ash Pond 1 through Pipe #1.
This collection pit contains two inlet pipes and one outlet pipe. The transducer sensor was
installed facing the primary inlet (operations water inlet), approximately 1 foot from the
apparent highest velocity observed in the sump, following guidelines from the ISCO 750
Area Velocity Module Installation and Operation Guide (Teledyne Isco, 2013). The flow
meter and sampler were powered via an external battery located at the surface of the
collection pit. Daily average, maximum, and minimum velocities and liquid heights
within the collection pit were recorded.
GR8879/CLRS Evaluation Report_Rev 0 5 08.09.22

4.2.2. Collection of Flow Rate Data
As described in Section 4.1, five inflows/outflows to/from Ash Ponds 1 and 2 were
identified to form the framework to calculate the water balance. Data sources and
management are described below for each flow stream.
Inflows
• Pipe #1: Average, maximum, and minimum velocities and water levels were
recorded from the field event. Table 1 provides the daily measurements and
associated flow rate calculations. The cross -sectional area of the flow path was
calculated to assess flow rate. The collection pit was roughly 4 feet by 4 feet; a
buildup of ash within the pit created a flow path that was reduced to approximately
3 feet in width. The measured water levels provided the height of water within the
flow path. Flow rate was calculated by multiplying the flow velocity by the cross -
sectional area (CSA), as follows:
Flowrate (Q) = Velocity x CSA
• Pipe #2: Inflow from Pipe #2 is assumed to be negligible, as described in Section
4.1.
• Precipitation: Thirty years of daily precipitation data (January 30, 1992 to January
30, 2022) was retrieved from a National Oceanic and Atmospheric Administration
(NOAA) gauge in Whiteville, North Carolina (USC00319357). The 80th
percentile of the daily precipitation rate was calculated per month. As the flow
rate measurement of Pipe #1 was performed in June, the precipitation input for
the water balance included the calculated June data. The surface areas of Ash
Ponds 1 and 2 were obtained from measurements taken from satellite images of
the Site. The precipitation inflow was calculated by multiplying the June
precipitation by the total surface area of the Ash Ponds. The volume entering the
ash ponds from precipitation was converted from a monthly flow rate to gpm for
the water balance. Table 2 outlines the precipitation data calculated per month and
the inflow estimated for the month of June.
Outflows
• PET: Thirty years of observed daily maximum and minimum temperature data
was retrieved from the NOAA gauge described above. The surface areas of Ash
GR8879/CLRS Evaluation Report_Rev 0 6 08.09.22

Ponds 1 and 2 were obtained from measurements taken from satellite images of
the Site. The Thornthwaite method (Ponce, 1989) was used to calculate average
PET per month over the surface area of Ash Ponds 1 and 2. PET was converted
from an average monthly flow rate to flow rate in gpm for the water balance. Table
3 provides further details regarding the calculation of PET.
• Recirculation Pump: The rolling thirty -day average flow rate in gpm for the pump
was measured by Site personnel.
GR8879/CLRS Evaluation Report_Rev 0 7 08.09.22

5. RESULTS
The results and uncertainties of the water balance evaluation are described in the sections
that follow.
5.1. Water Balance
The results of the water balance calculation are shown in the inset table below. Average
flow rates for inflows and outflows were used to perform the calculation. The water
balance was calculated as the sum of inflows minus the sum of outflows from the Ash
Ponds. The overall balance for the month of June, when the flow rate was measured at
Pipe #1, is 16.5 ± 48.2 gpm. Although the calculation suggests a positive water balance,
the calculated balance is within one standard deviation of the measured inflows from the
collection pits (Pipe #1) which indicates that the CLRS operates as a closed loop although
the uncertainty associated with inflows is high.
Inflows (gpm)
Outflows (gpm)
Balance
(Inflows -
Outflows)
(gpm)
Pipe #1
(Collection
Pits)Washdown
Pipe #2
(Vehicle
Area)
Precipitation
Recirculation
Pump
Potential
Evapotranspiration
PET
(PET)
65.6* ± 48.2
0
2.78
49.1
2.82
16.5
45.1
(median)
0
2.78
49.1
2.82
-4.04
*Note: Flow rates presented here are average values. See Section 4.2.2 for details on calculation
of these averages.
5.2. Uncertainties
Daily average flow rates measured at Pipe #1 during the field event ranged from 41.6 to
137.4 gpm. The overall average flow rate during the measurement period was 65.6 gpm
with a median of 45.1 and standard deviation of 48.2. The 95% confidence interval (CI)
for Pipe #1 measurements was calculated as follows:
Standard deviation
CI = Mean flow rate ± (.95) x
.Number of samples
GR8879/CLRS Evaluation Report_Rev 0 8 08.09.22

The CI for Pipe# 1 ranged from 42.7 to 88.5 gpm. Since the average is greater than the
median, it is likely that Pipe #1 flows would be below 65.6 gpm for a majority of the time.
This is supported by the highest average Pipe #1 flow rate being out of range of the CI
(137.4 gpm). This outlier is likely driving the average flow rate higher than the median
resulting in a skewed average. Using the median inflow (45.1 gpm), the water balance
was calculated as -4.04 gpm.
The flow rate for Pipe #2 measured by Site personnel was a rolling 30-day average flow
rate of the recirculation pump. This measurement does not capture daily variability like
and may contribute uncertainty to the water balance.
Precipitation flow rates into the Ash Ponds exhibit less variability than the measured Pipe
#1 flow rates. Monthly precipitation flow rates range from 0.44 to 3.80 gpm.
Potential evapotranspiration flow rates out of the Ash Ponds also exhibit less variability.
Monthly flow rates range from 0.18 to 3.06 gpm.
GR8879/CLRS Evaluation Report_Rev 0 9 08.09.22

6. SUMMARY
As shown in Section 5, the inflows and outflows from the Ash Ponds are similar; the
difference between them is within one standard deviation of the inflows measured at Pipe
#1 (± 48.2 gpm). As described, the average Pipe #1 flow rate appears to be skewed high.
Based upon the statistics for Pipe #1 flow rates, it can be inferred that future inflows from
Pipe #1 will likely be less than 65.6 gpm, which brings the overall water balance closer
to zero. If the median flow rate from Pipe #1 is used in this calculation, the balance
decreases to -4.04 gpm. Therefore, it appears that the CLRS operates as a closed -loop
system although the uncertainties appear to be high.
Alterations to the Armour Mill Plant in recent years have prompted a modification to the
Site's CLRS permit. To confirm the closed -loop nature of the Site, CLRS processes were
evaluated to develop a water balance for the CLRS. A review of the CLRS identified
three sources of inflow and two sources of outflow from the Ash Ponds. Flow rate
measurements, as well as historical weather and temperature data, were utilized to
calculate flow rates to and from the Ash Ponds. Based on the calculated balances of
inflows and outflows, and considering the observed data variability, the evaluation
indicates that the CLRS operates as a closed -loop system. In response to the uncertainties
identified during the water balance study, West Fraser, Inc. is evaluating options for
further modifications to Site infrastructure to be able to better assess water flows at the
Site.
GR8879/CLRS Evaluation Report_Rev 0 10 08.09.22

7. REFERENCES
North Carolina Department of Environmental Quality. Permit No. WQ0003468: Armour
Lumber Mill CLRS. Linda Culpepper. North Carolina Environmental
Management Commission, 2019.
Ponce, V.M. 1989. Engineering Hydrology: Principles and Practices. Englewood Cliffs,
New Jersey: Prentice Hall.
Teledyne Isco. 2013. 750 Area Velocity Module: Installation and Operation Guide.
GR8879/CLRS Evaluation Report_Rev 0 11 08.09.22

TABLES

Table 1. Pipe #1 Flow Meter Data and Flow Analysis
Geosyntec Consultants of NC, P.C.
West Fraser, Inc.
Riegelwood, NC
Date
Width
of
Flow
Path
(ft)
Height (ft)
CSA (sq ft)
Velocity (fps)
Flow Rate (cfs)
Flow Rate (gpm)
Average
Max
Min
Average
Max
Min
Average
Max
Min
Average
Max
Min
Average
Max
Min
6/27/2022
3
0.451
0.62
0.37
1.353
1.86
1.107
0.08
0.15
-0.08
0.1
0.3
-0.1
48.6
125.4
-39.7
6/28/2022
3
0.518
0.78
0.43
1.554
2.34
1.287
0.05
0.24
-0.23
0.1
0.6
-0.3
34.9
252.0
-132.8
6/29/2022
3
0.486
0.61
0.44
1.458
1.84
1.314
0.21
0.21
0.07
0.3
0.4
0.1
137.4
173.0
41.3
6/30/2022
3
0.343
0.58
0.28
1.029
1.74
0.837
0.09
0.29
-0.08
0.1
0.5
-0.1
41.6
226.1
-30.1
Assumptions:
were measured within the collection pit. See Section 4.2 for details.
Average
65.6
194.1
-40.3
Median
45.1
199.6
-34.9
1. Height and Velocity
Stdev
48.2
56.4
71.5
2. Collection pit dimension = 4 ft x 4 ft
3. Estimated width of flow path (due to ash buildup) = 3 ft
4. CSA = width of flow path x height of water
5. The geometry of the CSA is assumed to be rectangular.
6. For simplicity, the flow path at the measurement point is assumed to be straight and laminar.
7. Friction losses due to ash buildup were not calculated.
8. Flow rate = CSA * velocity
Acronyms:
cfs = cubic feet per second
CSA = cross -sectional area
fps = feet per second
ft = feet
gpm = gallons per minute
stdev = standard deviation
sq ft = square feet
GR8879
August 2022

Table 2. Precipitation Flow Rates into Ash Ponds 1 and 2
Geosyntec Consultants of NC, P.C.
West Fraser, Inc.
Riegelwood, NC
Month
Daily
Precipitationll'21
(80th Percentile,
in/day)
Volume of
Precipitation Over
AP 1131 (ft3/day)
/day)
Volume of
Precipitation
Over AP 2 [41
(ft3/day)
Total
Precipitation
/day)
(ft3/day)
Total
Precipitation
(gal/day)
Flow Rate of Precipitation into
Ash Ponds
(gpm)
January
0.11
211
99
310
2,318
1.61
February
0.14
268
126
394
2,950
2.05
March
0.1
192
90
282
2,107
1.46
April
0.068
130
61
192
1,433
0.99
May
0.1
192
90
282
2,107
1.46
June
0.19
364
171
535
4,003
2.78
July
0.18
345
162
507
3,792
2.63
August
0.26
498
234
732
5,478
3.80
September
0.14
268
126
394
2,950
2.05
October
0.03
58
27
85
632
0.44
November
0.05
96
45
141
1,053
0.73
December
0.092
176
83
259
1,938
1.35
Notes:
1. Historical precipitation data retrieved from NOAA Station "Whiteville 7 NW, NC, US" from January 30, 1992, through January 30, 2022.
2. The 80th percentile daily precipitation is calculated per month over a 30-year dataset.
3. Surface area of AP 1 is approximately 23,000 ft2.
4. Surface area of AP 2 is approximately 10,800 ft2.
Acronyms:
AP 1 = Ash Pond 1
AP 2 = Ash Pond 2
ft = feet
gal = gallons
gpm = gallons per minute
in = inches
NOAA = National Oceanic and Atmospheric Administration
GR8879
August 2022

Table 3. Potential Evapotranspiration Flow Rates from Ash Ponds 1 and 2
Geosyntec Consultants of NC, P.C.
West Fraser, Inc.
Riegelwood, NC
Month
Avg.
TempI21
(°F)
Avg.
Temp
(°C)
I
J
c
Flow Rate
of
Preci itatio
p
n into Ash
Ponds
(gpm)
K�3�
PET
(cm/month)
PET
(in/month)
PET in AP 1
3
(ft /month)
PET in AP 2
3
(ft /month)
Total PET
(gal/month)
Flow Rate from
Ash Ponds
(gpm)
Annual
82.06
1.82
January
44.19
6.77
1.58
1.13
0.84
0.95
0.37
715
336
7,858
0.18
February
46.96
8.31
2.16
1.64
0.91
1.49
0.59
1,128
529
12,395
0.31
March
53.48
11.93
3.73
3.16
1.00
3.15
1.24
2,374
1,115
26,092
0.58
April
62.12
16.73
6.23
5.84
1.08
6.32
2.49
4,772
2,241
52,453
1.21
May
69.98
21.10
8.84
8.90
1.17
10.37
4.08
7,827
3,675
86,037
1.93
June
77.20
25.11
11.51
12.21
1.20
14.71
5.79
11,097
5,211
121,987
2.82
July
80.43
26.90
12.78
13.84
1.19
16.47
6.48
12,428
5,836
136,608
3.06
August
79.12
26.18
12.26
13.16
1.13
14.84
5.84
11,199
5,259
123,101
2.76
September
73.84
23.24
10.24
10.61
1.03
10.97
4.32
8,279
3,888
91,007
2.11
October
63.60
17.56
6.70
6.37
0.95
6.03
2.38
4,553
2,138
50,049
1.12
November
53.90
12.16
3.84
3.27
0.86
2.83
1.11
2,133
1,001
23,444
0.54
December
47.06
8.37
2.18
1.66
0.82
1.36
0.53
1,025
481
11,264
0.25
Notes:
1. PET flows calculated using Thornthwaite methodology obtained from: Ponce, V.M. 1989. Engineering Hydrology: Principles and Practices . Englewood Cliffs, N.J: Prentice Hall.
2. Historical temperature data retrieved from NOAA Station "Whiteville 7 NW, NC, US" from January 30, 1992, through January 30, 2022. Average was calculated from daily
maximum and minimum temperatures.
3. K is calculated using latitude of the facility, 34.3399°.
Acronyms:
AP 1 = Ash pond 1
AP 2 = Ash pond 2
Avg = average
°C = Celsius
cm = centimeters
°F = Fahrenheit
ft3 = cubic feet
gal = gallons
gpm = gallons per minute
in = inches
K = constant, dependent on month and latitude
NOAA = National Oceanic and Atmospheric Administration
PET = potential evapotranspiration
PET(0) = PET at 0° latitude
Thornthwaite Method Equations
c = 0.000000675J3 - 0.0000771/2 + 0.01792J + 0.49239
PET(0) = 1.6 (---)
lOT
PET = K * PET(0)
T = mean monthly temperature (°C)
I = monthly heat index
J = annual temperature efficiency index
c = constant, dependant on J
GR8879
August 2022

FIGURES

Miles
0 25 50 100 150 200
Legend
NC Counties
• Facility
A
SITE LOCATION
RIEGELWOOD, NC
Geosyntec
consultants West Fraser Figure
1
Geosyntec Consultants of NC, RC.
RALEIGH, NC AUGUST 2022

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NOTES:
1. SITE DIAGRAM BASEMAP PROVIDED BY WEST FRASER, INC.
CONTINUOUS
KILN
r BATCH KILN
COUNTY WATER
METER
SCRUBBER
WATER SOFTENER
BOILER
DECOMMISSIONED CENTRIFUGE
(REMOVED FROM SITE)
COLLECTION PIT
MAKEUP TANK
II
II
II
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PIPE #1 INLET
RECIRCULATION PUMP
PUMP HOUSE
OUTLET TO
RECIRCULATION PUMP
ASH POND 2
VEHICLE WASHDOWN AREA
0 1,500
SCALE IN FEET
PIPE #2
INLET
SITE DIAGRAM
RIEGELWOOD, NC
Geosyntec
consultants
,cosyntec Consultants of NC, P.0
PROJECT NO: GR8879 AUGUST 2022
FIGURE
2

FIRE WATER/
POTABLE WATER
1
CLOSED
COUNTY
WATER
NOTES:
MAKEUP TANK
SOFTENER
BOILER
-
CP
•
BLOWDOWN
SOFTENER BACKWASH
•
VEHICLE
WASHDOWN AREA
OIL WATER SEPARATOR
SW CP/CP
SW CP/CP
ASH POND 2
•
OLD O/W SEPARATOR
1. PROCESS FLOW DIAGRAM BASED ON GEOSYNTEC SITE VISIT ON MAY 10, 2022.
ASH POND 1
SOFTENER
Legend
CP — Collection Pit
SW CP/CP — Stormwater Collection Pit /
Collection Pit
Kilns
Water Softener
O/W — Oil Water Separator
PROCESS FLOW DIAGRAM
RIEGELWOOD, NC
Geosyntec
consultants
Geosyntec Consultants of NC, P.C.
RALEIGH, NC
1111 West Fraser
AUGUST 2022
Figure
3