2019.12.31_CCO.p16_ChemoursCorrectiveActionPlan-AppendixH

TR0795 December 2019
APPENDIX H
Numerical Groundwater Modeling Report

NUMERICAL MODELING
Chemours Fayetteville Works

Prepared for
The Chemours Company FC, LLC 22828 NC Highway 87
Fayetteville, NC 28306

Prepared by
Geosyntec Consultants of NC, P.C.
2501 Blue Ridge Road, Suite 430
Raleigh, NC 27607
Geosyntec Project Number TR0795

December 2019

TR0795 ii December 2019
TABLE OF CONTENTS
EXECUTIVE SUMMARY vi
1. INTRODUCTION ..................................................................................................... 1 1.1 Purpose of the Report ....................................................................................... 1
1.2 Approach .......................................................................................................... 1
2. GENERAL SETTING ............................................................................................... 2 2.1 Site Description and Surroundings ................................................................... 2
2.2 Geomorphologic Site Setting ........................................................................... 2
3. CONCEPTUAL MODEL ......................................................................................... 2
3.1 Aquifer System Framework ............................................................................. 3
3.1.1 General ................................................................................................. 3
3.1.2 EVS Model ........................................................................................... 5
3.2 Groundwater Flow System ............................................................................... 6
3.2.1 Perched Zone ........................................................................................ 6
3.2.2 Surficial Aquifer ................................................................................... 6
3.2.3 Black Creek Aquifer ............................................................................ 7
3.3 Boundaries, Sources and Sinks ........................................................................ 7
3.4 Water Budget ................................................................................................... 7
4. COMPUTER MODEL .............................................................................................. 8 4.1 Model Selection ............................................................................................... 8
4.2 Model Description ............................................................................................ 8
5. GROUNDWATER FLOW MODEL CONSTRUCTION ........................................ 8
5.1 Model Mesh ..................................................................................................... 8
5.2 Hydraulic Parameters ....................................................................................... 9
5.3 Flow Model Boundary Conditions ................................................................. 10
5.4 Selection of Calibration Targets ..................................................................... 11
6. CALIBRATION ...................................................................................................... 12
6.1 Residual Analysis ........................................................................................... 12
6.2 Seeps and Discharges ..................................................................................... 14
6.3 Sensitivity Analysis ........................................................................................ 14
7. PREDICTIVE SIMULATIONS .............................................................................. 15
7.1 Extraction Wells Scenario with no Barrier Wall ............................................ 20

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7.2 Extraction Wells Scenario and Barrier Wall .................................................. 20
7.3 Extraction Wells Scenario and Barrier Wall Adjacent to the Plant ............... 21
8. LIMITATIONS AND RECOMMENDATIONS .................................................... 21 8.1 Model Assumptions and Limitations ............................................................. 21
8.2 Summary and Recommendations ................................................................... 22
9. REFERENCES ........................................................................................................ 23

LIST OF TABLES
Table 1: Site Aquifer System
Table 2: Calibrated Model Hydraulic Parameters for Each Hydrostratigraphic Unit
Table 3: Final Calibrated Groundwater Flow Model Statistics
Table 4: Calibration to Seeps and Discharges
Table 5: Calibrated Model Sensitivity to Model Boundary Conditions and Hydraulic Parameters
Table 6: Summary of Prediction Scenarios
Table 7: Summary of Prediction Scenarios Results

LIST OF FIGURES
Figure 1: Site Location Map
Figure 2: Regional Topographic Map
Figure 3: Site Topographic Map
Figure 4: Typical Site Cross-Section
Figure 5: Overview of EVS Model
Figure 6: Model Computed Groundwater Elevation Map – Perched Zone, October 2019
Figure 7: Model Computed Groundwater Elevation Map – Surficial Aquifer, October 2019
Figure 8: Model Computed Groundwater Elevation Map – Black Creek Aquifer, October 2019
Figure 9: Comparison of Observed and Computed Hydraulic Head Elevations

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LIST OF APPENDICES
Appendix A: Extracts from EVS Model

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LIST OF ABBREVIATIONS
CAP Corrective Action Plan
CFRW Cape Fear River Watch
CO Consent Order
EVS Environmental Visualization System
ft feet
ft bgs feet below ground surface
ft/day feet per day
GPM gallons per minute
K hydraulic conductivity
HPT hydraulic profiling tool
LiDAR Light Detection and Ranging
MSL mean sea level
NCDEQ North Carolina Department of Environmental Quality
NRMS Normalized Root Mean Square
Pc capillary pressure
PFAS per- and polyfluoroalkyl substances
RMS Root Mean Square
Sr residual wetting phase saturation
Ss specific storage
Sw wetting phase saturation
USGS United States Geological Survey
WWTP wastewater treatment plant
α Brooks-Corey-Burdine constitutive fitted parameter, alpha
δ Brooks-Corey-Burdine constitutive fitted parameter, delta
λ Brooks-Corey-Burdine constitutive fitted parameter, lambda
θ unsaturated-flow porosity, theta

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EXECUTIVE SUMMARY
This numerical modeling report was prepared by Geosyntec Consultants of NC, P.C.
(Geosyntec) for The Chemours Company FC, LLC (Chemours) to assess groundwater
flow at the Chemours Fayetteville Works facility (Site) using numerical modelng,
pursuant to Paragraph 16 of the February 25, 2019 Consent Order (CO) among Chemours,
the North Carolina Department of Environmental Quality (NCDEQ) and Cape Fear River
Watch (CFRW). Paragraph 16 requires Chemours to submit a Corrective Action Plan
(CAP) for the Site by 31 December 2019.
The objective of the numerical modeling program is to develop a model for use in the
design and costing assessment of the various proposed groundwater remedies for the Site.
In addition, the model will aid in assessing the effectiveness of each remedy. Based on
the requirements of the modeling, the finite element code FEFLOW was chosen for the
project. The model is intended to be hydraulic only, to aid in assessment of pumping and
recharge reduction approaches. The model is not intended (in its current formulation) to
simulate contaminant fate and transport. The modeling was conducted in accordance
with NC guidance and the NCDEQ’s 2007 Groundwater Modeling Policy (NCDEQ,
2007). Initial model parameters were chosen based on the available field data and
published literature values where field data were not available. Calibration was performed
using a sequenced trial and adjustment approach.
The calibrated model developed had a Normalized Root Mean Square (NRMS) error of
12.5% which is considered satisfactory based on the scale of the model and its intended
end use in costing and preliminary design focusing on hydraulics only (as opposed to
contaminant fate and transport). The majority of the error in the calibrated model occurs
in the Perched Zone and will have limited effect of the ability of the model to predict
capture of groundwater discharge to the surface water bodies. The steep topography,
presence of a perched water bearing region, and lack of laterally extensive
hydrostratagraphic units in many regions of the model domain makes this a challenging
scenario to model, in both development and calibration stages.
Twenty simulations were conducted using the calibrated model to aid in the evaluation
of the appropriate groundwater remedy of the CAP. Table 7 presents a description of the
six key simulations examined in the model study area. All simulations consisted of
groundwater extraction in some cases coupled with a barrier wall along the Cape Fear
River. In general, to avoid capture of large volumes of water from the Cape Fear River, a
barrier wall was required. Groundwater extraction minimization simulations of the
location and extraction rates of the pumping wells (in combination with the barrier wall)
indicated that a well spacing of 200 feet with extraction rates between 20 and 35 GPM

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provided capture of groundwater discharge to the Cape Fear River without excessive
capture of Cape Fear River water.
Based on the results of the numerical modeling program, groundwater remedy
development would be supported by reducing uncertainty regarding:
• Interactions between the Surficial Aquifer and the Black Creek Aquifer along the bluffs; and
• Distribution of groundwater flows into surface water drainage features
including onsite groundwater seeps, Willis Creek and Old Outfall 002.
A combination of additional simulations and targeted field investigations (aquifer testing)
to address these uncertainties is recommended before final remedy design.

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1. INTRODUCTION
1.1 Purpose of the Report
This numerical modeling report was prepared by Geosyntec Consultants of NC, P.C.
(Geosyntec) for The Chemours Company FC, LLC (Chemours) to assess groundwater
flow at the Chemours Fayetteville Works facility (Site) using numerical modelng,
pursuant to Paragraph 16 of the February 25, 2019 Consent Order (CO) among Chemours,
the North Carolina Department of Environmental Quality (NCDEQ) and Cape Fear River
Watch (CFRW). Paragraph 16 requires Chemours to submit a Corrective Action Plan
(CAP) for the Site by 31 December 2019. This CAP describes how groundwater will be
remediated at Site with a primary focus on reducing Site associated per and
polyfluoroalkyl substances (PFAS) from reaching the Cape Fear River.
This document focuses on the development, calibration and implementation of the
numerical groundwater model to support remedy evaluation, selection and design at the
Site.
1.2 Approach
The model was developed in accordance with the guidelines described in the NCDEQ
2007 Groundwater Modeling Policy (NCDEQ, 2007) to help support potential future
discussions with the NCDEQ about modeling results and interpretations and decisions
based on modeling effort.
To meet this requirement, the report was prepared based on the following structure:
• Introduction (this section);
• General Setting (Section 2) – describes the Site and surrounding areas, and geomorphological Site setting;
• Conceptual Model (Section 2.2) – describes the geology and hydrogeology of the Site, and Site-specific hydrologic and hydraulic boundaries;
• Computer Model (Section 4) – describes the model selection process, the capabilities of the selected model;
• Groundwater Model Construction (Section 5) – describes the model mesh development, hydraulic parameters of hydrostratigraphic units, groundwater
model boundary conditions based on available Site-specific data, and selected
model calibration targets;
• Calibration (Section 6) – discusses the residual and sensitivity analysis results of the model calibration process;

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• Predictive Simulations (Section 7) – discusses the results of the predictive simulation suite performed to assess different groundwater extraction remedial strategies;
• Summary and Conclusions (Section 8) – discusses model assumption and
limitations, and recommendations for potential future modeling efforts;
• References (Section 9).
2. GENERAL SETTING
2.1 Site Description and Surroundings
The Site is located within a 2,177-acre property at 22828 NC Highway 87, approximately
20 miles southeast of the city of Fayetteville along the Bladen-Cumberland county line
in North Carolina. Figure 1 presents an overview of the Site location. Figure 2 presents a
regional topographic map and Figure 3 presents a higher resolution topographic map of
the Site.
The Site is bounded by NC Highway 87 to the west, Cape Fear River to the east, and on
the north and south by forested areas, farmland and private residences. Zoning maps
indicate that the surrounding areas are zoned as residential, agricultural, conservation,
industrial or commercial.
The manufacturing area of the Site covers approximately 312 acres (Figure 3). Chemours
also operates a wastewater treatment plant (WWTP) at the Site. The remaining areas are
grassy areas, forests and wetlands.
2.2 Geomorphologic Site Setting
The Site is located on the Coastal Plain. In North Carolina, the Coastal Plain
Physiographic Province extends from the present Atlantic Ocean inland to the Fall Line,
an erosional contact boundary with the Piedmont Province. The Fall Line is
approximately 40 miles northwest of the Site.
Most of the Site sits on a rather flat-lying area at typical elevations ranging from 125 feet
above mean sea level (ft MSL) to 150 ft above MSL (Figure 3). The topography mildly
slopes from the western boundary towards the north, east and south. The slope then
steepens quite abruptly in these directions, resulting from incisions carved by surface
water courses including:
• Towards the north, coinciding with the course of Willis Creek where the topography decreases to elevations ranging between 35 ft above MSL and 70
ft above MSL;

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• Towards the east, coinciding with the course of the Cape Fear River where the elevation drops sharply to approximately 35 ft above MSL, forming a bluff face between the Site and the River;
• Towards the south, coinciding with the course of Georgia Branch Creek where
the topography decreases to elevations ranging between 35 ft above MSL and
110 ft above MSL.
A topographic incision also coincides with the Old Outfall 002, sloping more mildly in
the southern portion of the Site.
Willis Creek and Georgia Branch Creek are tributaries to the Cape Fear River. Willis
Creek flows in an easterly direction and was observed to have flow rates around 2,900
gallons per minute (GPM) in dry weather and around 6,500 GPM following rainfall.
Georgia Branch Creek, which is offsite for its entire course, is flowing in a southeasterly
direction and was observed to have flow rates between 2,400 and 2,600 GPM in both wet
and dry weather. Georgia Branch Creek runs northwest-southeast beside Highway 87
before turning east towards the Cape Fear River to the south of the Site. The median flow
rate in the Cape Fear River is in the order of 750,000 GPM.
3. CONCEPTUAL MODEL
3.1 Aquifer System Framework
3.1.1 General
Multiple aquifer units occur underneath the Site, which are summarized in Table 1 (from
youngest to oldest) while their typical positions in the vertical profile are illustrated in
Figure 4.
Table 1: Site Aquifer System
Unit Description Classification Typical
K-values*
Floodplain
Deposits
Predominantly fine-grained deposits.
Closely associated with the Cape Fear River
course, typically 10 to 15 ft in thickness.
Aquitard (where
fine-grained),
local aquifer
(where more
sandy)
0.1 ft/day
to 1 ft/day

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Unit Description Classification Typical
K-values*
Perched Zone Predominantly loose silty sand, brown to
reddish brown. Relatively thin in the eastern
portion of the Site to a depth of about 20 ft
below ground surface (bgs). In the western
portion, an inferred erosional feature has
likely resulted in the unit being thicker.
Unconfined
perched
groundwater
body of local
extent, porous
medium
2 ft/day to
5 ft/day
Perched Clay Predominantly stiff clay with minor silts,
dark grey. Also spatially limited. Pinching
out to the north. To the east and south,
outcrops along the bluff face. To the west,
terminates and becomes absent, presumably
eroded by the erosional feature.
Aquitard of
local extent,
porous medium
< 1ft/day
Surficial
Aquifer
Predominantly fine to medium-grained
sand, white to light brown. Mostly
continuous layer across Site area, typically
20 ft to 40 ft thick with a mild dip to the
south. In the western portion, the absence of
Perched Clay does not enable to
differentiate the contact with the lithology
representing the Perched Zone.
Unconfined
aquifer, porous
medium
2 ft/day to
5 ft/day
Black Creek
Confining
Unit
Predominantly organic-rich clay, hard, dark
grey to black. Regionally extensive layer,
20 ft to 40 ft thick with a mild dip to the
south.
Aquitard of
regional extent,
porous medium
<1 ft/day
Black Creek
Aquifer
Predominantly dense medium-grained sand,
dark grey. Regionally extensive layer,
typically 20 ft to 40 ft thick. Thins out in the
Cape Fear River vicinity (up to less than 5
ft), likely due to erosion and emplacement
of recent Floodplain Deposits.
Confined
aquifer of
regional extent,
porous medium
5 ft/day to
80 ft/day
Cape Fear
Confining
Unit
Predominantly clay, hard. Regionally
extensive layer.
Aquitard of
regional extent,
porous medium
<1 ft/day
Notes to Table: *Sourced from the On and Offsite Assessment Report (Geosyntec, 2019) and the Additional Site
Investigation Report (Parsons, 2018). Aquifer values derived from aquifer testing (i.e. slug test and pumping test),
aquitard values derived from grain-sized analysis.

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In the western portion of the Site (Figure 4), an erosional feature (i.e. paleochannel) is
indicated to occur. The erosional feature is interpreted to have completely eroded the
Perched Clay, enabling direct hydraulic connection between the Perched Zone and the
Surficial Aquifer. In parts (northwest), the erosional feature is also interpreted to have
incised into the top of the Black Creek Aquifer.
3.1.2 EVS Model
A three-dimensional (3D) hydrostratigraphic model of the Site was constructed using
CTech’s Earth Volumetric Studio (EVS) software (https://www.ctech.com/products
/earth-volumetric-studio/). The EVS model was developed to interpolate the
hydrostratigraphic model, along the horizontal and vertical directions, and develop the
model mesh for the numerical groundwater model.
A review of the available borehole logs, hydraulic profiling tool (HPT) logs and
geological mapping observations indicated that the horizontal and vertical distribution of
available data varied throughout the Site; with a dense distribution in some areas (e.g.,
onsite observations of the Perched Zone) and sparse in others (e.g., western portion of the
Site, south of Old Outfall 002, and onsite observations below the Perched Clay). The EVS
model was therefore constructed using an iterative process, by generating and
incorporating control points which were guided by the cross-sections from the On and
Offsite Assessment Report (Geosyntec, 2019), field observations and professional
judgement.
A review of the available borehole logs also suggested that the hydrostratigraphic units
within the Site vicinity are not continuous and not hierarchically layered (i.e., not
“pancake” layered), especially in units above the Black Creek Aquifer. The “indicator
kriging” method was therefore utilized to develop the EVS model. This approach
involved computing the probability for each hydrostratigraphic unit at every cell within
the model domain, and then assigning the unit with the highest probability to the cell.
Using this approach, the EVS model was constructed using the kriging interpolation
method. Model input parameters were selected based on a review of the overall data
distribution, visual comparisons of results with various input parameters, overall
interpolating computing time and software limitations. A total of 98 boring locations, 28
HPT locations, 42 geological mapping observations, and 36 control points were
incorporated to the EVS model.
The top of the model (i.e., ground surface) was determined based on the Light Detection
and Ranging (LiDAR) data from NC Dept. of Public Safety published on 18 October
2015. The streambeds of the Willis Creek and Old Outfall 002 were further refined based
on surveyed data. The bottom of the model was set to -20 ft MSL, which is below the

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Black Creek Aquifer and intersects the Cape Fear Confining Unit. However, the bottom
of the model does not represent the bottom of the Cape Fear Confining Unit.
An overview of the EVS model is presented in Figure 5. Visuals from the EVS model are
also provided in Appendix A, which includes an the EVS model boundary, aerial view of
the input data, and model outputs in aerial views, 3D views and cross-sectional views
along selected portions of the Site.
3.2 Groundwater Flow System
The groundwater flow system in the Perched Zone, Surficial Aquifer and Black Creek
Aquifer and their relative interactions are briefly described in the following sections.
Further description is available in the On and Offsite Assessment Report (Geosyntec,
2019).
3.2.1 Perched Zone
Groundwater levels in the Perched Zone are distributed according to a mound-like shape.
Higher groundwater levels are indicated in the northeast of the manufacturing area,
typically over 140 ft above MSL. Lower groundwater levels, at the edge of the mound,
are less than 120 ft above MSL, coinciding with the edge of the Perched Clay or the bluff.
Groundwater from the Perched Zone is anticipated to be a manifestation of surface
infiltration due to its localized nature i.e. not in connection with regional flow.
Groundwater flow in the Perched Zone is likely to be radial i.e. outward from the top of
the mound. Groundwater from the Perched Zone discharges along the bluff, above the
contact between the Perched Zone and the Perched Clay. Groundwater from the Perched
Zone is also anticipated to recharge the Surficial Aquifer, either via leakage through the
Perched Clay or else via the erosional feature i.e. where the Perched Zone is directly
connected to the Surficial Aquifer.
3.2.2 Surficial Aquifer
Groundwater levels in the Surficial Aquifer range from above 115 ft above MSL in the
western area of the Site to about 90 ft above MSL in the northern and eastern areas.
Groundwater in this aquifer unit is indicated to predominantly flow in a northeasterly and
easterly direction, towards Willis Creek and the Cape Fear River, respectively.
Groundwater from the Surficial Aquifer also discharges near the toe of the bluff, above
the contact with the Black Creek confining unit. Discharge from the Surficial Aquifer
into the Old Outfall 002 is also likely where it cuts across this unit.
Groundwater in the Surficial Aquifer is recharged by the regional flow and leakage from
the above units.

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3.2.3 Black Creek Aquifer
In the eastern part of the Site, groundwater levels in the Black Creek Aquifer range from
90 ft above MSL near the top of the bluff to about 35 ft above MSL near the Cape Fear
River. There is limited information in the western part of the Site. Groundwater flow in
the Black Creek Aquifer is predominantly in an easterly direction, towards the river
although localized flow towards Willis Creek is anticipated where the creek is incised
into this aquifer. While the Cape Fear River acts as a groundwater discharge zone for the
Black Creek Aquifer, the steep gradient along the bluff (0.03 to 0.04 ft/ft) combined with
the thin section of the aquifer (up to less than 5 ft) likely indicates resistance to flow.
3.3 Boundaries, Sources and Sinks
The dominant hydrologic boundary is the Cape Fear River, which acts as the regional
groundwater discharge zone for the Black Creek Aquifer. The tributaries to the Cape Fear
River are also indicated to act as more localized hydrologic boundaries, with groundwater
from the Site variably interacting with these surface water bodies.
The bluff above the Cape Fear River acts as a seepage face. The steep slope results in
groundwater discharge above the interface between the two shallow aquifer units (i.e.
Perched Zone and Surficial Aquifer) and their underlying aquitard. The Cape Fear
Confining Unit is considered to form the base of the Site aquifer system, providing a
hydraulic barrier to the deeper hydrostratigraphic units (not included in the geologic or
numerical models).
The main source of water in the Perched Zone is indicated to be derived from Site
infiltration (both rainfall, stormwater recharge and infiltration from previously unlined
sediment ponds and ditches). The source of water in the Surficial Aquifer and the Black
Creek Aquifer are leakage from the shallower units and throughflow from the regional
aquifer system.
Responses from rainfall were assessed by comparing rainfall events against changes in
groundwater levels. Initial results from selected wells across the three aquifer units
indicated an increase in groundwater level following a 0.08-inch rain event after a lag
time typically ranging between 1.5 and 2 days.
3.4 Water Budget
Over the long term, the rate of water inflow to the Site is equal to the rate of water outflow
from the Site. Water enters the groundwater system from regional flow, Site rainfall,
stormwater recharge and infiltration from previously unlined sediment ponds and
previously ditches. Water leaves the system through discharge primarily to the Cape Fear
River via direct discharge and onsite groundwater seeps, and to a lesser extent discharge
to Willis Creek, Georgia Branch Creek, and Old Outfall 002. No water balance was

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developed for the Site during the EVS model development stage. One of the intended
outcomes of the numerical model is to provide an initial water budget estimate in order
to inform future work.
4. COMPUTER MODEL
4.1 Model Selection
The model is required to simulate variably saturated flow behaviors at the Site. The steep
topography surrounding the Site is challenging to simulate, and therefore a finite element
model was deemed to be more appropriate than a finite difference model. Various
commercially available finite element models were assessed based on their ability to meet
the study objectives and their maturity and acceptance in the scientific and regulatory
communities. FEFLOW (DHI-WASY) was the most suitable numerical model based on
those criteria.
4.2 Model Description
FEFLOW is a 3D finite element groundwater model widely recognized in industry,
research and government and considered to be an industry standard for finite element
groundwater modeling. The code uses the Richards’ equation, the conservation of mass,
and nonlinear relationships between capillary pressure (Pc) and wetting phase saturation
(Sw) and between Sw and hydraulic conductivity (K) to solve for hydraulic heads.
FEFLOW simulates 3D transient groundwater flow in unsaturated and variably saturated,
confined and unconfined heterogeneous systems, and models the dynamic interaction
with injection/extraction wells, recharge and surface water systems. This study used
FEFLOW version 7.2 for the numerical groundwater flow model simulations. All
groundwater models were simulated and post-processed within the built-in FEFLOW
graphical user interface.
5. GROUNDWATER FLOW MODEL CONSTRUCTION
5.1 Model Mesh
The EVS geologic model described in Section 3.1.2 of this report was translated into a
series of shape files representing each of the seven hydrostratigraphic units. The
numerical model mesh was developed using the contact points for the seven
hydrostratigraphic units, ground surface elevation from the LiDAR remote sensing
dataset and field measurements along Willis Creek and the Old Outfall 002. This data
were assembled and meshed within FEFLOW using the triangle mesh generation
algorithm. The model mesh contained 1,878,129 elements and 372,054 nodes. The model

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varies in thickness from about 170 ft on top of the bluff to 55 ft at the base of bluff near
the Cape Fear River.
5.2 Hydraulic Parameters
Initial model parameters were chosen based on the available field data (Geosyntec, 2019).
Where ranges in data existed, mid-points of the ranges were chosen as the initial set of
parameters. Hydraulic conductivity ranges for each hydrostratigraphic unit were
presented in Table 1.
Hydraulic conductivity, specific storage (Ss), unsaturated-flow porosity (θ), residual
wetting phase saturation (Sr), and Brooks-Corey-Burdine Pc-Sw-K constitutive parameters
(alpha (α), lambda (λ), delta (δ)) are the main hydraulic parameters in the model. The
distribution and assignment of these parameters is based on the conceptual model
hydrostratigraphy. Hydraulic parameter distribution in the model was uniform across
individual hydrostratigraphic units. The parameter values for each hydrostratigraphic unit
were determined during the flow model calibration process (Section 6) and presented in
Table 2.
Table 2: Calibrated Model Hydraulic Parameters For Each Hydrostratigraphic Unit
Hydrostratigraphic Unit K (ft/day) Ss (m-1) θ Sr (-) α (m-1) λ (-) δ (-)
Floodplain Deposits 1.4 1.0 x 10-8 0.32 0.2 0.5 0.15 25
Perched Zone 2.6 1.0 x 10-3 0.3 0.1 11.5 0.56 7.3
Perched Clay 0.0014 1.0 x 10-8 0.5 0.2 0.5 0.15 25
Surficial Aquifer 72 1.0 x 10-3 0.33 0.1 11.5 0.56 7.3
Black Creek Confining Unit 0.43 1.0 x 10-8 0.55 0.2 0.5 0.15 25
Black Creek Aquifer 144 5.1 x 10-5 0.34 0.1 11.5 0.56 7.3
Cape Fear Confining Unit 1.1 1.0 x 10-8 0.28 0.2 0.5 0.15 25

The hydraulic conductivities of the Surficial Aquifer and Black Creek Aquifer are greater
than the original estimates presented in Table 1 (see calibration section for additional
details). The estimates presented in Table 1 were based primarily on grain size
distributions. The calibrated hydraulic conductivity of the Surficial Aquifer is in
agreement with the aquifer test (72.3 ft/d) performed by Parsons (Parsons, 2018) and the
ratio of hydraulic conductivities of the Surficial and Black Creek Aquifers is in agreement
with the differences in geologic description based on the borehole logs (fine vs. medium
grained sand).
Sr and the Brooks-Corey-Burdine (α, λ, δ) constitutive parameters for each
hydrostratigraphic unit were selected based on the soil textural class and the estimated
model parameters reviewed from Madi et al. (2018), Matlan et al. (2014), and Shao and

TR0795 10 December 2019
Irannejad (1999). These parameter assignments were simplified for the model by
separating the hydrostratigraphic units as either aquifers or aquitards (see Table 1), after
performing the first set of flow model calibration runs where each hydrostratigraphic unit
was assigned distinct parameter sets. Aquifer units were assigned Sr and Brooks-Corey-
Burdine constitutive parameters representative of sands; aquitard units were assigned Sr
and Brooks-Corey-Burdine constitutive parameters representative of sandy clay, silty
clay, and clay soil types.
5.3 Flow Model Boundary Conditions
The numerical model extent is a subset of the EVS model extent. The lack of available
data on a regional scale required the model to be site-scale focused. Focusing on the Site
enabled a detailed examination and quantitation of the steep topography and steep vertical
gradients. The numerical model extent was closely tied to the boundary conditions chosen
for the model:
Top Boundary: Established as the ground surface, taken from a combination of LiDAR
data and topographic surveys performed along Willis Creek and the Outfall. Boundary
conditions on the top boundary were either constant flux (to simulate rainfall recharge)
or constant head equal to elevation (with a no inward flow constraint) to simulate seepage
faces on the bluffs. Initial rainfall recharge values were selected with reference to the
annual precipitation and evapotranspiration estimates for the Mid-Atlantic Coastal Plain
(United States Geological Survey (USGS), 2005).
Bottom Boundary: Chosen as flat at an elevation of -20 ft above MSL which is located
within the Upper Cape Fear confining unit. A no-flow hydraulic condition was applied
to the entire bottom boundary of the model.
Northern Boundary: Willis Creek forms a hydraulic boundary north of the model domain.
The creek is treated as a spatially-varying constant hydraulic head boundary from the
northwest model corner to the outflow to the Cape Fear River located at the northeast
model corner. The uppermost active nodes in the mesh along the Willis Creek boundary
were linearly interpolated, from west to east along the creek, from a hydraulic head equal
to the ground surface elevation at the westmost part of Willis Creek to a hydraulic head
equal to the constant hydraulic head boundary value of the Cape Fear River. Application
of this constant head condition to only the upper nodes in the mesh forces all groundwater
flowing towards the boundary to discharge into the creek (as all nodes below the upper
nodes were assigned a no-flow condition).
Eastern Boundary: The Cape Fear River forms a hydraulic boundary east of the model
domain. The river is treated as a constant hydraulic head boundary in the uppermost active
nodes with an elevation representative of a daily median water elevation in the river, as

TR0795 11 December 2019
measured at the W.O. Huske Dam (United States Geological Survey (USGS) 2105500).
The river wraps partially around the northeast and southeast corners of the model.
Application of this constant head condition to only the uppermost nodes in the mesh
forces all groundwater flowing towards the boundary to discharge into the river.
Southern Boundary: The model domain southern extent was chosen to represent a flow
line from the western boundary to the eastern boundary. This selection was based on the
available measured hydraulic head data and professional judgement (Geosyntec, 2019).
A no flow condition was applied to the southern boundary.
Western Boundary: The western model boundary is not bounded by any clearly defined
hydraulic features and may be a flow divide beneath a topographic high. This boundary
was chosen as parallel to the Cape Fear River as limited hydraulic information was
available to make a more refined choice. This boundary is located more than a quarter
mile from the manufacturing area of the Site. Spatially-varying constant hydraulic head
boundary conditions were applied linearly ranging from 125 ft (in the shallower portion
of the domain) or 122 ft (in the deeper portion of the domain) at the southern end of the
boundary to the elevation of Willis Creek at the northern end of the boundary.
5.4 Selection of Calibration Targets
The steady state flow model calibration targets were water level measurements taken at
77 of the 147 monitoring wells synoptically surveyed on October 15, 2019, screened in
the Perched Zone, Surficial Aquifer, and Black Creek Aquifer units (Geosyntec, 2019).
Of these 77 monitoring wells, 33 wells were located in the Perched Zone (Figure 6), 23
wells were located in the Surficial Aquifer (Figure 7), and 21 wells were located in the
Black Creek Aquifer (Figure 8). The focus of this modeling study was on flow behaviors
in the Black Creek Aquifer, and to a lesser extent the flow behaviors in the Surficial
Aquifer and Perched Zone. Computed nodal hydraulic heads at the approximate
reference well screen midpoint elevations in the FEFLOW model domain were compared
to the field measured hydraulic heads at these 77 wells. FEFLOW calculates hydraulic
heads at individual nodes rather than nodal intervals, therefore only monitoring well
locations which had field measured hydraulic heads greater or equal to their respective
well screen midpoints were included in the calibration analysis.
Seventy of the 147 wells from the October 15, 2019 synoptic water level survey were
excluded from the calibration analysis based on one or more of the following criteria:
• Wells located offsite (20 monitoring wells);
• Wells located outside of the model domain (3 monitoring wells);

TR0795 12 December 2019
• Wells screened within the Floodplain Deposits hydrostratigraphic unit (6 monitoring wells);
• Wells where the hydraulic head groundwater elevation measurement was lower than the elevation of the well screen midpoint (19 monitoring wells);
• Wells where water levels were not measured in this synoptic water level survey (10 monitoring wells);
• Wells where the well construction details were not available to estimate an
approximate well screen midpoint elevation (MW-7S); or
• Wells where the hydraulic head measured was considered anomalous/inconsistent and was either not used in the groundwater elevation contour development (pre-calibration) or removed from calibration analysis based on professional judgement and review (11 monitoring wells). For
example, a high density of wells exists to the immediate southwest of the plant in the vicinity of the top of Old Outfall 002. Three of these eleven wells were retained for the calibration, with MW-31, MW-33, MW-34, MW-35, MW-36, PZ-29, PZ-32, and PZ-34 excluded from the calibration analysis.
6. CALIBRATION
6.1 Residual Analysis
The groundwater flow model was calibrated using a staged approach starting with the
initial hydraulic parameter set described in Section 5.2 and the boundary conditions
described in Section 5.3. Calibration testing was performed by trial and adjustment,
evaluating the modeled hydraulic heads against the water level data described in Section
5.4. The final calibrated hydraulic parameters are presented in Table 3. Groundwater
recharge due to rainfall was determined to result in a best fit when 70% of rainfall
recharge (total precipitation multiplied by non-evapotranspiration fraction) was allowed
to infiltrate to the Perched Zone. Localized anthropogenic stormwater recharge (in
addition to rainfall recharge) and historical infiltration from previously unlined
sedimentation basins was also included distributed across the footprint of the plant at a
scoping level infiltration rate estimate of 80,000 GPD.
The final calibration statistics of the calibrated groundwater flow model are presented in
Table 3. A graphical comparison of the model computed hydraulic heads versus the
measured hydraulic heads from the October 2019 water level synoptic survey are
presented in Figure 9.

TR0795 13 December 2019

Table 3: Final Calibrated Groundwater Flow Model Statistics
Hydro-stratigraphic Unit
Number of Well Observations
Mean Hydraulic Head Residual (ft)
Minimum Hydraulic Head Residual (ft)
Maximum Hydraulic Head Residual (ft)
RMS Error (ft)
NRMS Error (%)
Perched Zone 33 -1.33 -9.91 7.86 4.59 25.2%
Surficial Aquifer 23 -2.93 -12.62 4.84 5.47 6.2%
Black Creek Aquifer 21 2.52 -4.37 10.57 5.43 6.2%
Notes: RMS – Root Mean Square. NRMS – Normalized Root Mean Square. Residuals are calculated as the difference
between computed hydraulic heads from the groundwater flow model and the measured hydraulic heads from the
October 2019 synoptic water level survey (Geosyntec, 2019).
Assessing a model calibration based on statistics derived from residuals is driven by the
end requirements of the model, its predictive use, and the quantity of quality data
available during the calibration process. The end use of the current model is to assist in
the design and costing of potential hydraulic approaches to managing flow into the Cape
Fear River. This end use allows for a greater level of uncertainty than a detailed
contaminant fate and transport modeling program used to inform risk. Overall, a
Normalized Root Mean Square (NRMS) error of less than 10% is considered acceptable
for the intended end use of this model. The calibration achieves this for the Surficial and
Black Creek Aquifers individually and also for the overall model when not separated into
individual hydrostratigraphic units. The calibration does not achieve this for the Perched
Zone, and additional calibration efforts may be required.
Computed hydraulic head contours and hydraulic head residuals are presented in Figures
6 to 8, for the Perched Zone, Surficial Aquifer, and Black Creek Aquifer, respectively.
Overall, the model computed hydraulic heads provide a reasonable fit to the October 2019
synoptic survey water level data in the Surficial Aquifer and Black Creek Aquifer units.
Outlier hydraulic heads (greatest residuals) can be grouped into three types:
• Overestimates of hydraulic head in the Black Creek Aquifer in the vicinity of the Cape Fear River (PW-10R, PIW-4D, PIW-9D, SMW-12).
• Underestimates of the hydraulic heads along the mid to bottom of the bluff
slopes in the Surficial Aquifer (MW-9S, PIW-5S, PW-03, SMW-09).

TR0795 14 December 2019
• Overestimates of the hydraulic head along the Cape Fear River bluffs in the Perched Zone (MW-23, MW-30).
There is likely a correlation between the tendency of the model to overpredict hydraulic
heads in the Black Creek Aquifer and underpredict hydraulic heads in the Surficial
Aquifer in similar geographical locations. It is likely that there is better hydraulic
communication across the Black Creek Confining Unit in the vicinity of the Cape Fear
River than is present in the model. Adjustments to the hydraulic conductivity of the Black
Creek Confining Unit resulted in poorer fits elsewhere in the model and no geologic
evidence is present in the borehole logs to indicate a localized phenomenon. The higher
hydraulic heads in the Black Creek Aquifer in the model result in larger gradients and
conservative overestimates of discharge to the Cape Fear River so additional,
unsupported localized parameter modifications were not attempted.
6.2 Seeps and Discharges
The model calibration process also included comparison of predicted seepage rates from
the Willis Creek and Cape Fear River bluffs as well as discharges to the Old Outfall 002
and the Cape Fear River. Results of this secondary calibration assessment are presented
in Table 4.
Table 4: Calibration to Seeps and Discharges
Seep/Discharge Target Measured/Estimated1 Modeled
Willis Creek Bluff Seeps > 50 GPM 102 GPM
Cape Fear River Bluff Seeps 280 GPM 34 GPM
Old Outfall 002 Flow 500 – 750 GPM 1,202 GPM2
Notes: 1Data taken from CAP or Investigation Report. 2This estimate includes discharge in the vicinity of
the Cape Fear River that likely is directly discharged to the river and as such is an overestimate of the actual
flow in the Old Outfall 002.
6.3 Sensitivity Analysis
Following model calibration, a sensitivity analysis was performed to key variables
modified during the calibration process or chosen based on literature values:
• Recharge due to rainfall;
• Perched Zone Hydraulic Conductivity;
• Surficial Aquifer Hydraulic Conductivity;
• Black Creek Aquifer Hydraulic Conductivity;

TR0795 15 December 2019
• Perched Clay Hydraulic Conductivity;
• Western Boundary Condition Hydraulic Head Distribution.
The sensitivity of the model calibration to each variable is assessed qualitatively and
quantitatively (where possible) in Table 5.
Table 5: Calibrated Model Sensitivity to Model Boundary Conditions and Hydraulic Parameters
Sensitivity Variable Change Sensitivity NRMS Error
Calibrated Model N/A N/A 12.5%
Rainfall Recharge +/- 20% Low 13.6%/12.7%
Perched Zone K +/- 50% Low 11.6%/13.3%
Surficial K +/- 20% Low 12.7%/12.8%
Black Creek K +/- 20% Low 12.4%/12.7%
Perched Clay K Across three orders of magnitude High
31.7% at reference hydraulic conductivity. Sensitivity limited to Perched Zone.
Western Boundary Condition
Change in spatial distribution of hydraulic heads and absolute values of
hydraulic heads
Moderate
Wide range depending on changes. Sensitivity limited to Surficial and
Black Creek, limited sensitivity in Perched Zone.

The higher calibration assessment statistics (poorer fit) of the model in the Perched Zone
are primarily due to the small range of observed hydraulic heads in the system (as
compared to the Surficial and Black Creek Aquifers). The distribution of hydraulic heads
in the Perched Zone is likely dependent on the actual locations of anthropogenic recharge
which have been spatially variable over time. The model used a uniform spatially
distributed recharge (in addition to rainfall recharge) to replicate the general mounding
observed at the Site. This approach captured the overall behavior but does not capture
the detailed spatial variability to a high degree of certainty.
7. PREDICTIVE SIMULATIONS
The predictive simulations were designed to investigate the effectiveness of extraction
gallery well field distribution as a mechanism to capture the groundwater discharging to
the Cape Fear River. The modeling conducted was comprised of the following:

TR0795 16 December 2019
• Extraction Wells Scenario with no Barrier Wall at the Base of the Bluff;
• Extraction Wells Scenario and Barrier Wall at the Base of the Bluff; and
• Extraction Wells Scenario and Barrier Wall Adjacent to the Plant.
A summary of the simulations conducted are presented in Table 6. For each scenario a
base case was established, and sensitivity analyses were completed to assess and
minimize the simulated degree of groundwater capture needed to reduce discharge to the
Cape Fear River.
Table 6: Summary of Prediction Scenarios
Scenario Type Scenario Description Number of Extraction Wells
Extraction Wells Scenario with no Barrier Wall at the Base of the Bluff
Well Spacing at 50 ft and a uniform pumping rate of 30 GPM
164
Well Spacing at 50 ft and a spatially variable pumping rate between 20 to 40 GPM
Well Spacing at 50 ft and a spatially variables pumping rate between 20 to 40 GPM, adjusted hydraulic conductivity
within the Surficial and Black Creek Aquifers as sensitivity analysis Extraction Wells Scenario and Barrier Wall at the Base of the Bluff
Well Spacing at 200 ft spacing with a uniform pumping rate at 20 GPM
41
Well Spacing at 200 ft spacing with a spatially variable pumping rate between 20
to 30 GPM
Well Spacing at 200 ft spacing with a spatially variable pumping rate between 20 to 30 GPM, adjusted extraction location
towards the bluff as sensitivity analysis
Well Spacing at 200 ft spacing with a spatially variable pumping rate between 20 to 30 GPM, adjusted hydraulic conductivity within the Surficial and Black Creek Aquifers as sensitivity analysis
Well Spacing at 250 ft spacing with a uniform pumping rate at 30 GPM 31 Well Spacing at 250 ft spacing with a spatially variable pumping rate between 20 to 30 GPM

TR0795 17 December 2019
Scenario Type Scenario Description Number of Extraction Wells
Well Spacing at 250 ft spacing with a spatially variable pumping rate between 20 to 30 GPM, adjusted extraction location
towards the bluff as sensitivity analysis
Well Spacing at 250 ft spacing with a spatially variable pumping rate between 20 to 30 GPM, adjusted hydraulic
conductivity within the Surficial and Black Creek Aquifers as sensitivity analysis Extraction Wells Scenario and Barrier Wall Adjacent to the Plant
Extraction wells west of the plant area. Well spacing of 200 ft with a uniform pumping rate of 40 GPM 49
Extraction wells east of the plant area.
Well spacing of 200 ft with a uniform pumping rate of 40 GPM 51
Extraction wells west of the plant area. Well spacing of 250 ft with a uniform pumping rate of 40 GPM 36
Extraction wells east of the plant area. Well spacing of 250 ft with a uniform pumping rate of 40 GPM 38

The following assumptions were made for the predictive model runs:
• Model parameters were taken from the model consistent with the model discussed in Section 5.0;
• The model was run for a forecast period of 1 year; and
• Initial conditions were taken from the final head of the model consistent with the model discussed in Section 5.0.
A summary of the predictive simulation results is presented in Table 7.

TR0795 18 December 2019

Table 7: Summary of Prediction Scenarios Results
Scenario Type Scenario Description Number of Extraction Wells
Black Creek Groundwater Discharge
Rate into the Cape Fear River – Before Simulated Pumping (GPM)
Black Creek
Groundwater Capture Flow into the Cape Fear River – By Simulated Pumping (GPM)
Extraction Wells Scenario with no Barrier Wall at the Base of the Bluff
Well Spacing at 50 ft and a uniform pumping rate of 30 GPM
164
1151 3522
Well Spacing at 50 ft and a spatially variables pumping rate between 20 to 40 GPM 1151 3772
Well Spacing at 50 ft and a spatially variables pumping rate between 20 to 40 GPM,
adjusted hydraulic conductivity as sensitivity analysis
1445 3862
Extraction Wells Scenario and Barrier
Wall at the Base of the Bluff
Well Spacing at 200 ft spacing with a uniform pumping rate at 20 GPM
41
1551 1389
Well Spacing at 200 ft spacing with a spatially variable pumping rate
between 20 to 30 GPM
1551 1421
Well Spacing at 200 ft spacing with a spatially variable pumping rate
between 20 to 30 GPM, adjusted extraction location towards the bluff as
sensitivity analysis
1551 1459

TR0795 19 December 2019
Scenario Type Scenario Description Number of Extraction Wells
Black Creek Groundwater Discharge Rate into the Cape Fear River – Before Simulated Pumping (GPM)
Black Creek Groundwater Capture Flow into the Cape Fear River – By Simulated Pumping (GPM)
Well Spacing at 200 ft spacing with a spatially
variable pumping rate between 20 to 30 GPM, adjusted hydraulic
conductivity as sensitivity analysis
1551 1532
Well Spacing at 250 ft spacing with a uniform
pumping rate at 30 GPM
31
1551 1419
Well Spacing at 250 ft spacing with a spatially variable pumping rate between 20 to 30 GPM
1551 1322
Well Spacing at 250 ft spacing with a spatially variable pumping rate between 20 to 30 GPM,
adjusted extraction location towards the bluff as sensitivity analysis
1551 1337
Well Spacing at 250 ft
spacing with a spatially variable pumping rate between 20 to 30 GPM,
adjusted hydraulic conductivity as sensitivity analysis
1551 1446
Extraction
Wells Scenario and Barrier Wall Adjacent to the Plant
Extraction wells east of the
plant area. Well spacing of 200 ft with a uniform pumping rate of 40 GPM
49 1551 1021
Extraction wells west of the plant area. Well spacing of 200 ft with a uniform pumping rate of 40 GPM
51 1551 822

TR0795 20 December 2019
Scenario Type Scenario Description Number of Extraction Wells
Black Creek Groundwater Discharge Rate into the Cape Fear River – Before Simulated Pumping (GPM)
Black Creek Groundwater Capture Flow into the Cape Fear River – By Simulated Pumping (GPM)
Extraction wells east of the plant area. Well spacing of
250 ft with a uniform pumping rate of 40 GPM
36 1551 824
Extraction wells west of the plant area. Well spacing of 250 ft with a uniform pumping rate of 40 GPM
38 1551 719

7.1 Extraction Wells Scenario with no Barrier Wall
The initial model assumed an extraction well spacing of 5 feet apart along the base of the
bluff between Willis Creek and the Old Outfall 002. These pumping scenarios indicated
dewatering would occur along sections of the aquifer at the base of the bluff, resulting in
significant capture of water from the Cape Fear River. Additional model runs were
completed with the aim of reducing the capture of Cape Fear River water while providing
capture of groundwater discharge. The minimal pumping scenario, based on the model
runs completed, recommended the extraction gallery wells spacing of 50 feet apart.
7.2 Extraction Wells Scenario and Barrier Wall
The initial model assumed an extraction well spacing of 200 to 250 feet apart along the
base of the bluff between Willis Creek and the Old Outfall 002. In addition to the
extraction well gallery a low permeability barrier wall was placed between Cape Fear
River and the extraction wells. A uniform pumping rate of 30 GPM was applied along
the extraction galley of 41 wells. This extraction rate resulted in a groundwater depression
along the base of the bluff between the extraction wells and the barrier wall. Additional
model runs were completed to refine the extraction rate and spacing within the extraction
gallery. The minimal pumping scenario, based on the model runs completed,
recommended the extraction gallery wells to have a well spacing of 200 feet, and a
variable pumping rate along the extraction gallery wellfield between 20 to 35 GPM. This
scenario results in a minimum of excess produced water while still providing capture of

TR0795 21 December 2019
discharging groundwater and minimal to no flow from the Cape Fear River to the
extraction gallery.
In addition to the groundwater extraction minimization analyses for the remedial design
simulations sensitivity analysis was also completed by increasing the hydraulic
conductivities of hydrostratigraphic units to emphasize the flow interactions between the
aquifer units and adjusted the recharge rate. The results indicated that the model is
moderately sensitivity to the changes in hydraulic conductivity and is not sensitivity to
the changes in recharge for the Black Creek Aquifer.
7.3 Extraction Wells Scenario and Barrier Wall Adjacent to the Plant
The initial model assumed an extraction well spacing of 200 to 250 feet apart west and/or
east of the plant. Similar to the scenario of pumping along the Cape Fear River, this
scenario resulted in dewatering of the aquifer along section at the base of the bluff,
resulting in significant capture of water from the Cape Fear River. Model runs were
completed with the goal of reducing the capture of water from the Cape Fear River and
reducing the dewatering of the aquifers. The minimal pumping scenario, based on the
model runs completed, recommended the extraction gallery wells spacing be less than
200 feet apart if extraction wells are placed above the bluff adjacent to the plant and
required pumping rates to be above 40 GPM. The groundwater extraction minimization
process indicated that greater volumes of extraction are required to provide the required
hydraulic control at the base of the bluff as compared to other scenarios.
8. LIMITATIONS AND RECOMMENDATIONS
8.1 Model Assumptions and Limitations
The hydrogeologic conditions that control the movement of groundwater in the
subsurface are complex and, as such, assumptions and simplifications must be made
during the construction of the numerical model that are used to simulated groundwater
flow. The following assumptions were made in the design of the Chemours Fayetteville
Works groundwater flow model and should be considered when assessing any model
predictions in the future:
• The model domain was limited to the spatial extent where hydrogeological data was available;
• Boundary conditions are aligned with geological and hydraulic boundaries
identified within the EVS model;
• Changes to geology derived via the EVS model and Site data during the calibration process were avoided where possible; and

TR0795 22 December 2019
• The model was calibrated to an average steady-state condition based on data from October 2019.
• The modeling conducted for the Site was challenging from both design (three
dimensional, spatially variable hydrostratigraphy, unsaturated, and steep
topography driving steep hydraulic gradients) and calibration (day-long
simulation times, significant hours to make changes to the complex model
between calibration runs) standpoints. There are some identified regions of
error in the predictions that are likely tied to uncertainties in the conceptual
site model, and these could impact on the design of groundwater remedies for
the Site. The process of site investigation – modeling – design is best
undertaken in an iterative manner, with feedback from each step incorporated
into the following steps.
8.2 Summary and Recommendations
The calibrated FEFLOW model meets the requirements of the NCDEQ’s 2007
Groundwater Modeling Policy (NCDEQ, 2007) and supports remedy evaluation,
selection and design at the Site. The calibrated model is deemed sufficiently accurate for
the modeling goals of this work however new data should be incorporated into both the
conceptual and numerical models when it becomes available.
Numerical modeling is an effective technique for identifying areas of uncertainty in
conceptual models and source-pathway-receptor models. Based on the results of the
numerical modeling program, groundwater remedy development would be supported by
reducing uncertainty regarding:
• Interactions between the Surficial Aquifer and the Black Creek Aquifer along the bluffs; and
• Distribution of groundwater flows into surface water drainage features including onsite groundwater seeps, Willis Creek and Old Outfall 002.
A combination of additional simulations and targeted field investigations (aquifer testing)
to address these uncertainties is recommended before final remedy design.

TR0795 23 December 2019
9. REFERENCES
Diersch, H.J.G. 2014. FEFLOW: Finite Element Modeling of Flow, Mass and Heat
Transport in Porous and Fractured Media. Springer-Verlag Berlin Heidelberg.
2014.
Geosyntec, 2019. On and Offsite Assessment Report, Chemours Fayetteville Works.
Geosyntec Consultants of NC, PC. September 30, 2019.
Madi, R., de Rooij, G.H., Mielenz, H., & Mai, J. 2018. Parametric soil water retention
models: critical evaluation of expressions for the full moisture range. Hydrology
and Earth System Sciences, 22. 2018.
Matlan, S.J., Mukhlisin, M., & Taha, MR. 2014. Performance Evaluation of Four-
Parameter Models of the Soil-Water Characteristic Curve. The Scientific World
Journal, 2014(569851). 2014.
NCDEQ, 2007. Groundwater Modeling Policy, North Carolina Department of
Environmental Quality. May 31, 2007.
Parsons, 2018. Additional Site Investigation Report, Chemours Fayetteville Works Site,
RCRA Permit No. NCD047368641-R1. March 30, 2018.
Shao, Y., & Irannejad, P. 1999. On The Choice of Soil Hydraulic Models in Land-Surface
Schemes. Boundary-Layer Meteorology, 90(1). 1999.
USGS. A Surficial Hydrogeologic Framework for the Mid-Atlantic Coastal Plain,
Professional Paper 1680. 2005.

TR0795
FIGURES
")
")
")
Willis Creek
Old Outfall 002Cape Fear RiverOutfall 002
W.O. Huske Dam
Site River Water Intake
NC Highway 87Seep A
Seep B
Seep C
Seep D
G BCTributary1GeorgiaBranchCreek
Site Location Map
Figure
1Raleigh
2,000 0 2,0001,000 Feet
³Path: P:\PRJ\Projects\TR0795\Database and GIS\GIS\Onsite and Offsite Assessment Report\TR0795_SiteLocation.mxd; 10/31/2019December 2019
Legend
")Site Features
Site Boundary
Nearby Tributary
Observed Seep (Natural Drainage)
Site Drainage Network
Notes:1. The outline of the Cape Fear River shown on this figure is approximate (River outline based on compilation of open data sources fromArcGIS online service and North Carolina Department of Environmental Quality Online GIS - Major Hydro shapefile).2. Basemap sources: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GISUser Community
Chemours Fayetteville Works, North Carolina
Areas at Site
Chemours Monomers IXM
Former DuPont PMDF Area
Wastewater Treatment Plant
Kuraray SentryGlas®Leased Area
Kuraray Trosifol®Leased Area
DuPont Polyvinyl FluorideLeased Area
Chemours PolymerProcessing Aid Area Power - Filtered andDemineralized WaterProduction
Kuraray Laboratory
Regional Topographic Map
Chemours Fayetteville Works, North Carolina
Figure
2Raleigh
2 0 21 Miles
³Path: P:\PRJ\Projects\TR0795\Database and GIS\GIS\Onsite and Offsite Assessment Report\TR0795_TopographicMap_6mile.mxd Last Revised: 10/30/2019 Author: TIpDecember 2019
Projection: NAD 1983 StatePlane North Carolina FIPS 3200 Feet; Units in Foot US
Notes:1. For topographic map symbols, please refer to this document: https://pubs.usgs.gov/gip/TopographicMapSymbols/topomapsymbols.pdf 2. Basemap source: © 2013 National Geographic Society, i-cubed
Legend
Site Boundary
")
Old Outfall 002
Site Drainage Network
To Outfall 002
W.O. Huske Dam
Willis Creek
Georgia Branch Creek
Outfall 002Ca
p
e
F
e
a
r
R
i
v
e
r
Site Topographic Map
Chemours Fayetteville Works, North Carolina
Figure
3Raleigh
2,000 0 2,0001,000 Feet
Path: P:\PRJ\Projects\TR0795\Database and GIS\GIS\Onsite and Offsite Assessment Report\TR0795_SiteTopgraphicMap.mxd; SSomnarain; 10/30/2019December 2019
Notes:Basemap sources: Esri, Garmin, USGS, NPS (World Terrain Reference); Esri, USGS, NGA, NASA, CGIAR, N Robinson, NCEAS, NLS, OS, NMA, Geodatastyrelsen, Rijkswaterstaat, GSA, Geoland, FEMA, Intermap and the GIS user community (World Hillshade)
Legend
")Site Features
Site Boundary
County Boundary
Observed Seep (Natural Drainage)
Nearby Tributary
Site Drainage Network
³
02ft NAVD88 - feet in 1988 North American Vertical DatumVertical Exaggeration = 15x1. Lithology between borings is interpolated and estimated. 2. Groundwater elevations calculated from measured depth to water on 15 October 2019.3. Cape Fear River water level indicated is median value for 15 October 2019 measured at the W.O. Huske Dam (USGS 2105500). Data obtained from National Water Information System (URL: https://waterdata.usgs.gov/nwis/inventory/?site_no=02105769, date accessed: 2019-09-24).4. Geological Mapping Locations from Figure 6-1. Approximate mapping elevations listed in Table 6-1.5. Seeps observed reported in Seeps and Creeks Investigation Report (Geosyntec, 2019)
ft NAVD88 - feet in 1988 North American Vertical DatumVertical Exaggeration = 15x
01150
125
100
75
50
25
0
1,000 2,000 3,000 4,000 5,000Elevation (ft NAVD88)Feet
%%

WeVt (aVt
Notes
e ro sional surfaceMW-17D (100 ft)00Figure
Raleigh December 2019
5ZQJDBM
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Chemours Fayetteville Works, North Carolina
Legend
Data/PRJ/Projects/TR0795/Database and GIS/Illustrator/Onsite and Offsite Assessment Report/Numeric Modeling cross-sections/TR0795_CrossSectionB_B'.aiFine to Medium Sand
Clay
Predominantly Fine to Medium-grained Sand
Floodplain Deposits
Fine to Medium-grained Sand with Variable Silt Content
Micaceous Clay
Silty or Sandy Claywith Organics

Location Name
Offset Distance+/- north/south of line
Well Screen NAF-11A (+103 ft)NAF-11B (+105 ft)MW-22D (-27 ft)LTW-02HP-22(90 ft)03PIW-4DHP-21PW-15R (+77 ft)BCA-03R (-77 ft)PZ-11 (-43 ft)MW-15DRR (-78 ft)NAF-02 (-107 ft)NAF-03 (-200 ft)NAF-07 (+131 ft)NAF-06 (+13 ft)MW-17D (-45 ft)MW-16D (-56 ft)Perched Zone
Surficial Aquifer
Upper Cape Fear
Confining Unit
Black Creek
Confining Unit
Black Creek Aquifer
8QGLIIereQWLDWeG
Surficial Aquifer
Power Area LinedSediment
Basin
Chemours
MonomersIXM AreaKuraray Butacite® Leased Area; Kuraray SentryGlas® Leased Area
Seeps observed
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Seep A
"
"Perched Clay
(97 ft)"
"
Cape FearRiver"
"04Seeps observed
Seeps observed
Geologic Mapping Location 34
Geologic Mapping Location 32/33
Geologic Mapping Location 29/31
Geological Mapping Location
Corresponds to Section
Black Creek Aquifer Groundwater Elevation
Perched Zone
Groundwater Elevation
Surficial Aquifer Groundwater Elevation
110.98
102.94
64.55
139.43 138.92
134.48
130.58
137.02
117.09
103.37
94.24
113.02113.82
101.27
76.96
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'
''
''''''
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'''
''
'''
AAA
A
AA
A
A
A
AAA
A
A
AAAAAA
A
A
A
A AAA AAA
A
AA
A
A AA
A
AA
AA
AAA
A
A
AA
AAAAAA
A
AAAAAAAA
BCA-01
BCA-02
BCA-03R
BCA-04
FTA-01
FTA-02 FTA-03
INSITU-01 INSITU-02
LTW-01
LTW-02
LTW-03
LTW-04
LTW-05
MW-12S MW-13D
MW-14D
MW-15DRR
MW-16DMW-17D
MW-18D
MW-19D
MW-1S
MW-20D
MW-21D
MW-22D
MW-23
MW-24
MW-25
MW-26
MW-27
MW-28
MW-2S
MW-30
MW-7S
MW-8S
MW-9S
NAF-01
NAF-02
NAF-03NAF-04
NAF-05A
NAF-05B
NAF-06
NAF-07
NAF-08A
NAF-08B
NAF-09NAF10
NAF-11A
NAF-11B
NAF-12
NAF-13PZ-11
PZ-12
PZ-13
PZ-14
PZ-15
3=R
3=R3=R
PZ-22
PZ-24
PZ-25
PZ-26PZ-27PZ-28
3=
SMW-02SMW-02B
SMW-03
SMW-03BSMW-04A
SMW-04B
SMW-05
SMW-05P SMW-06
SMW-06B
SMW-07
SMW-08SMW-08B
SMW-09
SMW-12
3,W'
3,WS
3,W'
3,W'
3,WS
3,WS
3,W'
3,W'R
3,WS
3,W'
3,W'
3,WS
3,WS3,W'
3W
3W
3W
3W
3W
3W
3W
3W
3W
3WCapeFearRiverB
B'
1,000 0 1,000500 Feet
³
((

((

")")
")
A-1 A-2
GP-103PZ-17
MW-11
Figure
5
Overview of EVS Model
Chemours Fayetteville Works, North Carolina
Raleigh December 2019
Units
Perch Zone
Perch Clay
Floodplain Deposits
Surficial
Black Creek Confining Unit
Black Creek Aquifer
Cape Fear Confining Unit1
Water Features
Elevation Contour Line
(every 5-ft)
Cape Fear River
Old Outfall 002
Willis Creek
Note
1.Bottom of the model does
not represent the bottom of
the Cape Fear Confining Unit.
@A
@A
@A
@A
@A
@A
@A
@A
@A
@A
@A
@A
@A
@A
@A
@A@A
@A
@A
@A
@A
@A
@A
@A@A
@A
@A
@A
@A
@A
@A
@A
@A
C
a
p
e
FearRi
verW illisC r e e k
Seep A
Seep B
Seep C
Seep D
FTA-01131.07 (-2.54)
FTA-03131.92 (-0.98)
MW-1S126.99 (-3.70)MW-2S120.45 (-9.91)MW-9S135.28 (2.47)
MW-12S131.46 (-0.15)
MW-23141.79 (7.86)
MW-25134.48 (1.19)
MW-27126.98 (-5.01)
MW-28123.16 (-7.04)MW-32
128.36 (-4.00)
NAF-02140.50 (1.07)
NAF-04138.37 (-1.62)
NAF-07138.24 (-0.68)
NAF-08A
145.15 (6.61)
NAF-09143.68 (7.30)NAF-10133.83 (-1.93)
PW-01126.91 (-6.64)
PZ-11133.60 (-3.42)
PZ-12130.67 (-0.07)
PZ-19R133.77 (-1.77)
PZ-20R131.43 (-4.04)
PZ-21R133.54 (-2.68)
PZ-24131.47 (-1.89)
PZ-26133.25 (-1.55)
PZ-27129.71 (-4.26)
PZ-28127.35 (-7.79)
PZ-31127.36 (-3.34)
PZ-33128.49 (-4.23)
PZ-35133.78 (-2.54)
MW-30140.45 (7.44)PZ-15141.84 (6.72)
PZ-17119.15 (-2.66)1401
3
0
1251351351251301
3
0
1259085
150145705075
4
5120110140
125
130
10
5
100
95105957570
125
120
95
80
75
155145504515
5
14
5
1
5
0
1
4
5
14
5135 706555454540
45404535135806511560130
60
13585
357040
1
4
5
120
11510510
0
105654540
1551
5
5
155155 150150145145150150
145
140
135125125125
115115105
90
9570
70 706055
505045
505
0
4540
403
5
353
5
145
145
145
35
Model Computed Groundwater Elevation Map - Perched Zone, October 2019
Chemours Fayetteville Works, North Carolina
Figure
6Raleigh
³Path: P:\PRJ\Projects\TR0795\Database and GIS\GIS\Corrective Action Plan\TR0795_GW_Contours_Maps_PerchedZone_Oct2019.mxd Last Revised: 12/13/2019 Author: NBarNahoumDecember 2019
Projection: NAD 1983 StatePlane North Carolina FIPS 3200 Feet; Units in Foot US
1,000 0 1,000500 Feet
Notes:ft NAVD88 - feet North American Vertical Datum 1988.1. Groundwater contours were visually interpolated using the computed groundwater elevations from the calibrated groundwater flow model.2. Depth to water measurements collected on October 15, 2019 used to calculate the groundwater elevation residual.3. Groundwater elevation residuals are calculated as the difference between the model computed groundwater elevations and the field measured groundwater elevations from October 15, 2019. Groundwater elevation residuals are presented in brackets.4. Topographic contours from LiDAR Digital Elevation Model ground surfaceelevations collected by NC Dept. of Public Safety published 18 October 2015.5. Seep locations identified visually as reported in Geosyntec, 2019. Seeps and Creeks Investigation Report. Chemours Fayetteville Works. 26 August 2019.6. The outline of Cape Fear River is approximate and is based on open data from ArcGIS Online and North Carolina Department of Environmental Quality OnlineGIS (MajorHydro shapefile).7. Basemap source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community.
0.5 0 0.50.25 Miles
³
Legend
@A Monitoring Well
Groundwater Contours(ft NAVD88) - 5 feetinterval
Observed Seep
Nearby Tributary
Ground SurfaceElevation Contour (ftNAVD88) - 5 ft interval
Site Boundary
PW-01126.91 (-6.64)
Well Location
Model ComputedGroundwater Elevation(ft NAVD88)
Groundwater ElevationResidual (ft)
@A
@A
@A@A
@A
@A
@A
@A
@A
@A@A
@A
@A
@A
@A
@A
@A
@A
@A@A
@A
@A
@A
@A C
a
p
e
FearRi
ver
W illisC r e e k
Seep A
Seep B
Seep C
Seep D
MW-13D
97.64 (-6.69)
MW-14D106.63 (-3.04)
MW-16D112.18 (-0.84)
MW-17D114.65 (-2.44)
MW-18D83.82 (-3.46)
MW-19D78.72 (-9.52)
MW-20D86.12 (-3.39)
MW-21D103.18 (-2.53)
MW-22D112.22 (-1.60)
PIW-1D34.35 (1.54)
PIW-5S52.24 (-8.22)
PW-0283.66 (-6.39)
PW-05122.33 (1.08)
MW-15DRR102.69 (-0.68)
PW-0394.52 (-11.05)
SMW-03B
98.24 (4.84)
SMW-05P104.89 (-0.42)
SMW-06B105.48 (2.33)
SMW-08B108.37 (0.08)
SMW-0972.58 (-12.62)
SMW-10
50.72 (4.03)
SMW-1149.83 (-8.04)
SMW-04B102.60 (-0.34)
60
70
65
110
75
80
105
100
95
90
85
6
0
7065
1107
5
80
1051009590859085150145705075
4
5
13595
140
120 13012511
5
80
60
105957570125
120
95
80
75
155145504515
5
14
5
1
5
0
1
4
5
14
5135 110105 706555454540
4540453565105
100130
60
13585
357040
1
4
5
120
11510
0
105956545 40
1551
5
5
155155 150150145145150150
145
140
135125125125
115115105
90
9570
70 706055
505045
505
0
4540
403
5
353
5
145
145
145
35
Model Computed Groundwater Elevation Map - Surficial Aquifer, October 2019
Chemours Fayetteville Works, North Carolina
Figure
7Raleigh
³Path: P:\PRJ\Projects\TR0795\Database and GIS\GIS\Corrective Action Plan\TR0795_GW_Contours_Maps_SurficialAquifer_Oct2019.mxd Last Revised: 12/13/2019 Author: NBarNahoumDecember 2019
Projection: NAD 1983 StatePlane North Carolina FIPS 3200 Feet; Units in Foot US
1,000 0 1,000500 Feet
Notes:ft NAVD88 - feet North American Vertical Datum 1988.1. Groundwater contours were visually interpolated using the computed groundwater elevations from the calibrated groundwater flow model.2. Depth to water measurements collected on October 15, 2019 used to calculate the groundwater elevation residual.3. Groundwater elevation residuals are calculated as the difference between the model computed groundwater elevations and the field measured groundwater elevations from October 15, 2019. Groundwater elevation residuals are presented in brackets.4. Topographic contours from LiDAR Digital Elevation Model ground surfaceelevations collected by NC Dept. of Public Safety published 18 October 2015.5. Seep locations identified visually as reported in Geosyntec, 2019. Seeps and Creeks Investigation Report. Chemours Fayetteville Works. 26 August 2019.6. The outline of Cape Fear River is approximate and is based on open data from ArcGIS Online and North Carolina Department of Environmental Quality OnlineGIS (MajorHydro shapefile).7. Basemap source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community.
0.5 0 0.50.25 Miles
³
Legend
@A Monitoring Well
Groundwater Contours(ft NAVD88) - 5 feetinterval
Observed Seep
Nearby Tributary
Ground SurfaceElevation Contour (ftNAVD88) - 5 ft interval
Site Boundary
PW-0394.52 (-11.05)
Well Location
Model ComputedGroundwater Elevation(ft NAVD88)
Groundwater ElevationResidual (ft)
@A
@A
@A
@A @A
@A
@A
@A
@A
@A
@A
@A
@A
@A
@A
@A
@A
@A
@A
@A@A
@A
W illis C r e e k
Ca
p
e
Fear
Ri
ver
Seep A
Seep B
Seep C
Seep D
BCA-0183.01 (-4.37)
BCA-0278.36 (3.81)
BCA-04122.16 (0.61)
BCA-03R102.42 (1.15)
PW-10R58.28 (10.13)
PW-12103.14 (10.49)
LTW-0242.40 (0.21)
LTW-0542.47 (0.12)
PIW-2D63.28 (-1.27)PIW-3D41.89 (6.09)
PIW-4D51.70 (10.02)
PIW-7D45.36 (2.67)
PIW-8D43.86 (2.75)
PIW-9D52.65 (10.57)
PW-0950.10 (-2.14)
PW-1140.00 (0.40)
PW-13116.56 (-3.23)PW-1484.52 (-2.34)
PW-15R75.62 (-1.34)
PZ-2243.53 (-0.53)
SMW-1242.51 (9.07)
110
105
95
100
90
85
50
45
75
80
70
65
60
55
11010595100908550457580706560559085150145705075
4
5120110140
125
130
10
5
100
95105957570
125
120
95
80
75
155145504515
5
14
5
1
5
0
1
4
5
14
5135 70655545454045351358065 4
0
115 60130
60
13585
35307040
1
4
5
120
11510510
0
105654540
1551
5
5
155155 150150145145150150
145
140
135125125125
115115105
90
9570
70 706055
505045
505
0
4540
45 403
5
353
5
145
145
145
35
Model Computed Groundwater Elevation Map -Black Creek Aquifer, October 2019
Chemours Fayetteville Works, North Carolina
Figure
8Raleigh
³Path: P:\PRJ\Projects\TR0795\Database and GIS\GIS\Corrective Action Plan\TR0795_GW_Contours_Maps_BlackCreek_Oct2019.mxd Last Revised: 12/13/2019 Author: NBarNahoumDecember 2019
Projection: NAD 1983 StatePlane North Carolina FIPS 3200 Feet; Units in Foot US
1,000 0 1,000500 Feet
Notes:ft NAVD88 - feet North American Vertical Datum 1988.1. Groundwater contours were visually interpolated using the computed groundwater elevations from the calibrated groundwater flow model.2. Depth to water measurements collected on October 15, 2019 used to calculate the groundwater elevation residual.3. Groundwater elevation residuals are calculated as the difference between the model computed groundwater elevations and the field measured groundwater elevations from October 15, 2019. Groundwater elevation residuals are presented in brackets.4. Topographic contours from LiDAR Digital Elevation Model ground surfaceelevations collected by NC Dept. of Public Safety published 18 October 2015.5. Seep locations identified visually as reported in Geosyntec, 2019. Seeps andCreeks Investigation Report. Chemours Fayetteville Works. 26 August 2019.6. The outline of Cape Fear River is approximate and is based on open data from ArcGIS Online and North Carolina Department of Environmental Quality OnlineGIS (MajorHydro shapefile).7. Basemap source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community.
0.5 0 0.50.25 Miles
³
Legend
@A Monitoring Well
Groundwater Contours(ft NAVD88) - 5 feetinterval
Observed Seep
Nearby Tributary
Ground SurfaceElevation Contour (ftNAVD88) - 5 ft interval
Site Boundary
PZ-2243.53 (-0.53)
Well Location
Model ComputedGroundwater Elevation(ft NAVD88)
Groundwater ElevationResidual (ft)
C:\Users\sbryck\Desktop\[Calibration Plot - Observed vs Computed Heads.xlsx]8_5 x 11 landscape_no clientComparison of Observed and Computed Hydraulic Head ElevationsChemours Fayetteville Works, North Carolina Figure9RaleighDecember 2019NotesNAVD88 - North American Vertical Datum of 19881. Observed hydraulic head elevations were obtained from asynoptic water level survey conducted on October 15, 2019.2. Computed hydraulic head elevations were obtained from thecalibrated steady state groundwater flow model.3. Orange line represents the ideal calibration scenario whereobserved and computed hydraulic heads are equal.Legend02550751001251500 255075100125150Computed Hydraulic Head Elevation (ft NAVD88)Observed Hydraulic Head Elevation (ft NAVD88)Black Creek AquiferSurficial AquiferPerched Zone

TR0795
APPENDIX A
EXTRACTS FROM EVS MODEL
(9S 0RGel 'Rmain
Cape Fear River
Old Outfall 002
Willis Creek
,nput 'ata fRr (9S 0RGel
Cape Fear River
Old Outfall 002
Willis Creek
(9S 0RGel 2utput ± 3lan 9ieZ
Cape Fear River
Old Outfall 002
Willis Creek
(9S 0RGel 2utput ± ' 9ieZ Facing 1RrtKZeVt
N
Vertical Exaggeration = 15x
Cape Fear River
Old Outfall 002
Willis Creek
(9S 0RGel 2utput ± ' 9ieZ Facing SRutKeaVt
N Vertical Exaggeration = 15x
Cape Fear River
Old Outfall 002
Willis Creek
(9S 0RGel 2utput ± ' 9ieZ 1RrtK %RunGar\
Vertical Exaggeration = 15x
East West
Cape Fear River
(9S 0RGel 2utput ± ' 9ieZ SRutK %RunGar\
Vertical Exaggeration = 15x
Cape Fear River
West East
(9S 0RGel 2utput ± ' 9ieZ (aVt %RunGar\
Vertical Exaggeration = 15x
South North
Cape Fear River Willis Creek
(9S 0RGel 2utput ± ' 9ieZ WeVt %RunGar\
Vertical Exaggeration = 15x
North South
Willis Creek
(9S 0RGel 2utput ± CrRVVSectiRnV in ' 9ieZ
Vertical Exaggeration = 15x
(9S 0RGel 2utput ± CrRVVSectiRnV in ' 9ieZ
Vertical Exaggeration = 15x
West Edge of Cape Fear River
Along Willis Creek
Along Old Outfall 002
A A’
(9S 0RGel 2utput ± CrRVVSectiRn $$¶
A (West)A’ (East)Elevation (ft NAVD88)Distance (ft)
Cape
Fear
River
B B’
(9S 0RGel 2utput ± CrRVVSectiRn %%¶
B (West)B’ (East)Elevation (ft NAVD88)Distance (ft)
Cape
Fear
River
Vertical Exaggeration = 15x
(9S 0RGel 2utput ± CrRVVSectiRn CC¶
C (West)C’ (East)Elevation (ft NAVD88)Distance (ft)
Cape Fear River
C C’
Vertical Exaggeration = 15x
(9S 0RGel 2utput ± CrRVVSectiRn ''¶
D (West)D’ (East)Elevation (ft NAVD88)Distance (ft)
Cape
Fear
River
D D’
Old Outfall 002
Vertical Exaggeration = 15x
(9S 0RGel 2utput ± CrRVVSectiRn ((¶
E (South)E’ (North)Elevation (ft NAVD88)Distance (ft)Vertical Exaggeration = 15x
E
E’
Old
Outfall
002
Willis
Creek
Vertical Exaggeration = 15x
(9S 0RGel 2utput ± CrRVVSectiRn $lRng WilliV CreeN
1 (West)1’ (East)Elevation (ft NAVD88)Distance (ft)Vertical Exaggeration = 15x
Cape Fear River
1
1’
Vertical Exaggeration = 15x
(9S 0RGel 2utput ± CrRVVSectiRn $lRng Cape Fear River
2 (North)2’ (South)Elevation (ft NAVD88)Distance (ft)Vertical Exaggeration = 15x
Old Outfall 002
Willis Creek
2’
2
Vertical Exaggeration = 15x
(9S 0RGel 2utput ± CrRVVSectiRn $lRng 2lG 2utfall 
3 (North)3’ (South)Elevation (ft NAVD88)Distance (ft)Vertical Exaggeration = 15x
Cape Fear River
3
3’
Vertical Exaggeration = 15x