WQ0002708_Groundwater Monitoring Results Memo_20210913

Groundwater
Monitoring Results
Memorandum
Wrenn Road Facility
City of Raleigh
Garner, NC
September 13, 2021

F]?
Table of Contents
Introduction 1
Sampling Plan Review 2
Monitoring Well Installation 2
Sample Collection and Methods 4
Results 5
Results Summary 5
Arsenic Results 5
Iron Results 6
Manganese Results 7
Conclusions 8
List of Tables
Table 1. Background Monitoring Well Summary 2
Table 2. Background Monitoring Well Results for Arsenic (November 2019 — March 2021) 5
Table 3. Background Monitoring Well Results for Iron (November 2019 — March 2021) 6
Table 4. Background Monitoring Well Results for Manganese (November 2019 — March 2021)7
List of Figures
Figure 1. Background and Compliance Monitoring Wells 3
Figure 2. Iron Results 6
Figure 3. Manganese Results 7
Appendices
Appendix 1 — Sampling and Data Analysis for Background Concentrations of As, Fe, and Mn in
Groundwater (2021)
Appendix 2 — Ground Water Monitoring Plan (2019)
Appendix 3 — Wrenn Road Monitoring Well Installation Report (2019)
Appendix 4 — Complete Groundwater Monitoring Results
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Introduction
The Wrenn Road Facility is located in Garner, NC, and currently receives water treatment
process residuals from the Dempsey E. Benton (DE Benton) Water Treatment Plant (WTP).
Liquid residuals are received through a 16-inch influent force main and spray -applied to the
site's 14 irrigation zones, which are spread among over 600 acres of fields and woodlands.
Historically, the facility disposed of treated wastewater from the Garner wastewater treatment
plant (WWTP). The facility has been operated by Raleigh Water since the merger of Garner's
water and wastewater utilities with the City of Raleigh (City) in 2001, and stopped receiving
waste from the sewer system in 2008 when wastewater flow was permanently redirected to the
Neuse River Resource Recovery Facility (NRRRF).
A comprehensive hydrogeologic and geochemical evaluation was performed in 2010 to evaluate
the site as part of the permit modification application'', 2. This study included the installation of
over 20 temporary piezometers and three monitoring wells, in addition to groundwater flow,
groundwater transport, and geochemical modeling. The two main purposes of the study were to:
1. Evaluate conditions before the DE Benton WTP residuals application, and
2. Identify recommended loading rates to the spray fields that would meet water quality
levels established in the modified permit.
The spray irrigation system and accompanying permit (WQ0002708) were modified to accept
DE Benton WTP residuals in 2012. As part of this permit, North Carolina Department of
Environmental Quality (NC DEQ) included the condition that the City prepare a monitoring plan
to assess if background concentrations of arsenic, iron, and manganese were above the levels
established in 15A NCAC 02L (referred to as "2L Standards"), which are as follows:
• Arsenic: 10 micrograms per liter (pg/L)
• Iron: 300 pg/L
• Manganese: 50 pg/L
Another goal of this sampling effort was to recommend site -specific background concentrations
for these constituents that are either the existing 2L Standards or higher concentrations if data
from the background samples is statistically greater than the standard. Data from the 2010
study was not used to establish background values because the wells were not permanent, and
their sampling may not have met the currently recommended sampling methodology for metals.
This memorandum provides an overview of the results obtained from the groundwater
monitoring wells. A complete analysis of the results of the monitoring efforts, including a
statistical analysis, is provided in Appendix 1, Sampling and Data Analysis for Background
Concentrations of As, Fe, and Mn in Groundwater (Eagle Resources, P.A., 2021). This
memorandum also briefly summarizes monitoring well installation and the sampling plan.
Soil and Environmental Consultants, 2009, Site Analysis for Wrenn Road Wastewater Treatment Plant Spray Irrigation System, Garner, Wake County, North Carolina.
2 Eagle Resources, P.A. May 10, 2010, Groundwater Mounding Analysis and Groundwater Quality Assessment Wrenn Road Wastewater Treatment Plant Spray Irrigation
System, Garner, Wake County, North Carolina.
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1

Sampling Plan Review
Future groundwater monitoring cannot be performed using the piezometers installed during the
2010 study since these piezometers were only designed to be temporary and have since been
abandoned. The three monitoring wells are not adequate in number or location to use for the
establishment of background concentrations. Therefore, a groundwater sampling plan was
developed and four new background monitoring well locations were identified with approval from
NC DEQ between February of 2017 and February of 2019. The complete sampling plan is
provided in Appendix 2, Ground Water Monitoring Plan (2019).
This sampling plan included information related to the following:
• Installation and development of four (4) background monitoring wells at the Wrenn Road
Facility,
• Establishment of sampling duration and sample collection protocols,
• Measurement of water quality parameters (iron, manganese, and arsenic) bi-monthly,
• Determination of whether the 2010 sampling data are from the same population as
2019/2020 data, and its use in defining background statistics for groundwater
monitoring,
• Establishment of well maintenance protocols to ensure future resampling of wells can
occur, if necessary.
Monitoring Well Installation
Four (4) background monitoring wells were installed in August of 2019. Background monitoring
well information is summarized in Table 1, including geographic coordinates, installation dates,
and depths. Figure 1 was developed by Eagle Resources, P.A. and presents a map of
background and monitoring well locations. Well locations were selected using model analyses
performed by Eagle Resources, P.A. and based on access requirements due to the
development of the adjacent residential subdivision. Wells were drilled and completed with
depths that extended at least into the Partially Weathered Rock (PWR) that lies beneath the soil
and saprolite. Additional information related to well installation can be found in the Wrenn Road
Background Monitoring Well Installation Report (2019), which is provided in Appendix 3.
Table 1. Background Monitoring Well Summary
el Easting Northing Installatio from Land Screened
Name Date Surface (ft) Intervals (ft)
PMW-1
•
2126151.11 691215.39 8/13/2019 43 33 to 43
PMW-2 2124505.08 691694.17 8/14/2019
20
10to20
PMW-3
2121970.60 688486.31 8/26/2019
16
6 to 16
PMW-4 2125522.18 687848.49 8/13/2019
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74 64 to 74
2

F
Mono.orknej Wells
• Background Monl!oring Well
• Compliance hloniLorrng well
Prhlvrty Roundirie. IwAk! County GI'}
Figure 1. Background and Compliance Monitoring Wells
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3

Sample Collection and Methods
The Ground Water Monitoring Plan (2019) provided in Appendix 2 describes the sample
collection and methods followed during this project in detail. Groundwater samples were
collected from each monitoring well on the same day during each sampling event. Before
collecting groundwater samples, monitoring wells were purged at a low flow until turbidity
reaches < 10 NTU or did not vary by more than 10%, and until pH and water temperature
measurements were stable. One duplicate sample was collected from one of the background
monitoring wells during each sampling event to evaluate consistency in field sampling methods
and laboratory analytical methods.
The first background monitoring well samples were collected in November of 2019 and
monitoring well sampling continued every other month for six months (January of 2020 and
March of 2020). Groundwater samples were measured by Raleigh Water staff in the field for pH,
conductivity, turbidity, and temperature. Laboratory parameters for samples collected through
November of 2020 were measured in the Raleigh Water laboratory for iron, manganese, and
arsenic. Iron, manganese, and arsenic samples collected in March of 2021 were analyzed by an
external laboratory.
The 2019 and 2020 sampling results were compared to results from 2010 sampling events to
evaluate any water quality changes that may have occurred. If these sampling results were
deemed statistically similar to the 2010 results, the 2019/2020 results could be combined with
2010 results to serve as the background iron, manganese, and arsenic concentrations. If the
results from the two sets of samples were statistically different, then only the 2019/2020 results
would be used.
The sampling dates for bi-monthly sampling were as follows:
• November 21, 2019
• January 17, 2020
• March 12, 2020
After the completion of bi-monthly monitoring well sampling, background well monitoring
continued using the same schedule used by Raleigh Water for existing compliance well
monitoring. Sampling has occurred in April, August, and November of 2020 and in March of
2021 to evaluate data trends in iron, manganese, and arsenic.
The dates for these sampling events are as follows:
• April 14, 2020
• August 20, 2020
• November 4, 2020
• March 10, 2021
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4

Results
The purpose of this section is to provide an overview of arsenic, iron, and manganese results.
The complete analysis of arsenic, iron, and manganese results is documented in Appendix 1,
Sampling and Data Analysis for Background Concentrations of As, Fe, and Mn in Groundwater
(2021), provided by Eagle Resources, P.A., and includes a statistical analysis to determine if
data are similar to those obtained in 2010.
During each sampling event, a log sheet was used to record sampling information (sample
collector(s), date/time, and weather condition(s)), field data (depth to water, total well depth,
volume of water purged before collecting the sample, turbidity, pH, temperature, and
conductivity), and laboratory data (iron, manganese, and arsenic). Complete groundwater
monitoring results are provided in Appendix 4.
Results Summary
Table 2, Table 3, and Table 4 present arsenic, iron and manganese results, respectively, from
six sampling events occurring from November of 2019 to March of 2021. Many parameters were
below detection limits.
Arsenic Results
Arsenic was below detection limits in each of the groundwater monitoring well samples collected
from November of 2019 through March of 2021, as shown in Table 2. In samples collected from
November of 2019 through November of 2020, the detection limit was 10 pg/L, which is also the
2L Standard. The arsenic detection limit was 5 pg/L for sample collected in March of 2021 due
to the use of an external laboratory. Since data were below detection, a statistical analysis was
not performed using arsenic data, and a time trend could not be developed .
Table 2. Background Monitoring Well Results for Arsenic (November 2019 — March 2021)
Well
Arsenic (pg/L) — Detection Limit: 10 lag/L (November of 2019 through
November of 2020) or 5 lag/L (March of 2021) — 2L Standard:10 pg/L
Nov Jan Mar April Aug Nov March
2019 2020 2020 2020 2020 2020 2021
PMW-1
< 10
< 10
< 10
< 10
< 10
< 10
< 5
PMW-2
< 10
< 10
< 10
< 10
< 10
< 10
< 5
PMW-3
< 10
< 10
< 10
< 10
< 10
< 10
< 5
PMW-4
< 10
< 10
< 10
< 10
< 10
< 10
< 5
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5

Iron Results
Table 3 and Figure 2 present iron results from November of 2019 to March of 2021. Iron levels
were often below the detection limits. Samples collected from November of 2019 to November
of 2020 were analyzed using a method detection limit of 60 pg/L, whereas the sample collected
in March of 2021 was analyzed using a method detection limit of 50 lag/L. Iron was detected in
one sample collected from PMW-1, with a value of 97 pg/L (March of 2021). Iron was detected
in two samples collected from PMW-2, with values of 72 pg/L (November of 2020) and 199 pg/L
(March of 2021). Iron levels only exceeded the 2L Standard of 300 pg/L in two samples, both
collected from PMW-3 (August of 2020 and March of 2021). There is a statistically significant
increase in iron in PMW-3, and there is a statistically significant decrease in iron in PMW-4,
which is described in detail in Sampling and Data Analysis for Background Concentrations of
As, Fe, and Mn in Groundwater (Appendix 1).
PMW-1
PMW-2
PMW-3
PMW-4
Table 3. Background Monitoring Well Results for Iron (November 2019 - March 2021)
Iron (pg/L) — Detection Limit: 60 pg/L (November of 2019 through November of
2020) or 50 pg/L (March of 2021) — 2L Standard: 300 pg/L
Nov Jan Mar April Aug Nov March
2019 2020 2020
2020 2020 2020 2021
< 60
< 60
< 60
< 60
< 60
< 60
< 60
< 60
199
< 60
141
< 60
172
68
< 60
< 60
700
600
500
J
'a 400
300
0
L
200
100
< 60 < 60 97
< 60 72
482
69
199
73 601
< 60 < 50
PMW-1 • PMW-2 ♦ PMW-3 PMW-4 —2L Standard
• • ••
•
0
rn rn 0 0 0 0 0 0 0
- N N N N N N N N N
1 1 1 Iffs
I I 1 ++ I I Iff
7 U
Z o li Q O 0
Date
Figure 2. Iron Results
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Manganese Results
Table 4 and Figure 3 present manganese results from November of 2019 to March of 2021.
Manganese levels were below detection in many samples collected from PMW-2 and PMW-3.
Samples collected from November of 2019 to November of 2020 were analyzed using with a
method detection limit of 50 pg/L, whereas the sample collected in March of 2021 was analyzed
using a method detection limit of 10 pg/L. Manganese exceeded the 2L Standard of 50 pg/L in
each sample collected from PMW-1, one sample collected from PMW-3 (March of 2021), and a
majority of samples collected from PMW-4. There is no statistically significant increase in
manganese in monitoring wells, which is described in detail in Sampling and Data Analysis for
Background Concentrations of As, Fe, and Mn in Groundwater (Appendix 1).
Table 4. Background Monitoring Well Results for Manganese (November 2019 — March 2021)
Well
Manganese (pg/L) — Detection Limit: 50 pg/L (November of 2019 through
November of 2020) or 10 pg/L (March of 2021) — 2L Standard: 50 pg/L
Nov Jan Mar April Aug Nov March
2019 2020 2020 2020 2020 2020 2021
PMW-1
90
74
64
70
88
59
71
PMW-2
< 50
< 50 < 50
< 50
< 50 < 50
16
PMW-3
PMW-4
200
180
160
�,140
120
100
•
a 80 •
Fa 60 • )1(
2 40
< 50 < 50
< 50
< 50
134 < 50
88
< 50 < 50
176
96 123 88
71
• PMW-1 • PMW-2 PMW-3 PMW-4 —2L Standard
♦
20 ♦
0
am am 0 0 0 0 0 0 0 r
N N N (-1N N N N N (.1.1 1 1 i 1 1 1 �+ 1 L
—)
Date
Figure 3. Manganese Results
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7

Iron and manganese results were used to develop probability curves and conduct an Analysis of
Variance Analysis (ANOVA). These exercises were conducted by Eagle Resources, P.A. to
determine if iron or manganese measured from November of 2019 through March of 2021 were
statistically similar to the results obtained in 2010. Based on this analysis, the data from the
2010 study is not statistically from the same population as the data from the compliance and
new background wells and should not be used in assessing site -specific background standards.
Conclusions
Arsenic levels remained below the detection limits of 10 pg/L (through November of 2020) and 5
pg/L (March of 2021) throughout the monitoring efforts conducted as part of this study.
Therefore, there is no statistical reasoning for setting a site -specific standard for arsenic greater
than the 2L Standard of 10 pg/L.
Data from the 2010 iron and manganese study and results reported as part of the November of
2019 to March of 2020 sampling are not statistically from the same population. Therefore, the
2010 data should not be used to assess site -specific background standards for iron and
manganese.
Iron levels were below detection in a majority of samples and exceeded the 2L Standard in two
samples (PMW-3, August of 2020 and March of 2021). Since the distributions for iron samples
are less than the 2L Standard of 300 pg/L, the 2L Standard should be used for compliance
purposes based on the data obtained to date. However, iron levels have changed over time in
some of the compliance and background wells since the start of compliance sampling in
November of 2019. Therefore, it is recommended to continue assessing iron levels on an
annual basis to determine if the iron standard for the site should be increased to a value greater
than the 2L Standard in the future.
Manganese levels were below detection in many samples, but above the detection limit and 2L
Standard in each of the samples collected from PMW-1 and PMW-4 and one sample collected
from PMW-3 (March of 2021). Additionally, the average manganese concentration was 66 pg/L,
which is greater than the 2L standard of 50 pg/L; therefore, it is recommended that the site -
specific background concentration for manganese be set at 66 pg/L.
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8

1
Sampling and Data Analysis
for Background
Concentrations of As, Fe,
and Mn in Groundwater
(2021)

4alie it'escrrces
Sampling and Data Analysis for Background Concentrations of
As, Fe, and Mn in Groundwater
Wrenn Road Wastewater Treatment Facility, Garner, NC
Prepared for:
HDR Engineering, Inc. of the Carolinas
and
City of Raleigh Public Utilities Department
March 18, 2021
Updated July 27, 2021
Eric G. Lappala, P.E.
Eagle Resources, P.A
215 West Moore Street
Southport, NC 28461
919-345-1013
www.eagleresources.com
1

tale Pe5otirces
Table of Contents
Introduction 1
Installation of new Background Monitoring Wells 1
Sampling of Background and Compliance Wells 3
Data Analysis 4
Probability Plots 4
Analysis of Variance 9
Pooling of new samples and the 2010 samples 12
Time Trends 13
Conclusions 17
Attachment 1 Approved Background Sampling Program 18
Attachment 2 Sampling Reports from CORPUD 19
Figures
Figure 1.-- Location of compliance and background wells and wells and piezometers sampled for the
2010 report 2
Figure 2.-- Cumulative probability plots for the log -transformed concentrations of Fe for background
samples and 2010 report unfiltered samples. 5
Figure 3.-- Cumulative probability plots for concentrations of Fe for background samples and 2010
report filtered samples. 6
Figure 4.-- Cumulative probability plots for concentrations of Fe in compliance wells and new
background wells 7
Figure 5.-- Cumulative probability plots for concentrations of Mn for background samples and 2010
report filtered samples. 7
Figure 6.-- Cumulative probability plots for concentrations of Mn for background samples and 2010
report filtered samples. 8
Figure 7.-- Cumulative probability plots for concentrations of Mn from compliance and new background
wells 9
Figure 8.-- Time trend in Fe and Mn in compliance well MW-B3. 13
Figure 9.-- Time trend in Fe and Mn in compliance well MW-B9. 14
Figure 10.-- Time trend in Fe and Mn in new background well PMW-3. 15
Figure 11.-- Time trend in Fe and Mn in new background well PMW-4. 16
i

Tables
Table 1.-- Results of laboratory analyses for As, Fe, and Mn from the background and compliance wells
sampled in 2019 and 2020. 3
Table 2.-- Results of laboratory analyses for As, Fe, and Mn from wells and piezometers reported in the
2010 report 4
Table 3.-- One-way ANOVA comparing the 2020 background values for Fe to the values for unfiltered
samples from 2010. 9
Table 4.-- One-way ANOVA comparing the 2020 background values for Fe to the values for filtered
samples from 2010. 10
Table 5.-- One-way ANOVA comparing the 2020 background values for Fe from the compliance wells
and the new background wells. 10
Table 6.-- One-way ANOVA comparing the 2020 background values for Mn to the values for unfiltered
samples from 2010. 11
Table 7.-- One-way ANOVA comparing the 2020 background values for Mn from the compliance wells
and the new background wells. 11
Table 8.-- One-way ANOVA comparing the values for Mn from the compliance wells vs. the new
background wells 12
Table 9.-- Regression analysis for the significance of the slope of the regression line for Fe in MW-B3.
13
Table 10.-- Regression analysis for the significance of the slope of the regression line for Fe in MW-B9.
14
Table 11.-- Regression analysis for the significance of the slope of the regression line for Fe in PMW-3.
15
Table 12.-- Regression analysis for the significance of the slope of the regression line for Fe in PMW-4.
16
Table 13.-- Regression analysis for the significance of the slope of the regression line for Mn in PMW-4.
16
ii

Introduction
This report documents the methodology recommended in the approved monitoring plan', and changes to
that methodology and the reasons for same to determine the statistically valid background concentrations
of Fe and Mn at the Wrenn Road Site. This update includes the results from samples collected on
03/10/2021 which concludes the approved sampling period.
The methodology is summarized as follows:
• Install new monitoring wells to assess concentrations of As, Fe and Mn that are hydraulically up
gradient or cross gradient from any field area to which treated effluent has been or may be applied.
• Sample the new wells and the three existing compliance wells (MW-B3, MW-B8m and MW-B9)
bi-monthly for one year using the purging and turbidity testing protocol specified in the approved
plan to reduce or eliminate high -turbidity samples (background samples).
• Compare the laboratory -determined concentrations of the three constituents in background
samples with the ones from samples collected from monitoring wells and temporary piezometers
as reported in the 2010 site investigation report2 to answer the following questions:
1. Are concentrations of the three constituents from the background samples statistically same as
those in Table 8 of the 2010 report (unfiltered samples)?
2. Are the filtered sample concentrations of the three constituents in Table 9 of the 2010 report
statistically the same as those from the background samples?
3. Are concentrations of the three constituents from the background samples from the new wells
from the same population as those from the three compliance wells?
• Based upon the answers to these questions, recommend a site -specific background concentration
for all three constituents that is either the existing NC 2L groundwater standard or a higher
concentration if data from the background samples is statistically greater than the standard.
Installation of new Background Monitoring Wells
The monitoring plan called for the installation and development of five (5) new background monitoring
wells. Owing to the availability of suitable background locations only four background wells (PMW-1,
PMW-2, PMW-3 and PMW-4) were approved by NC DEQ and installed as shown in Figure 1. The
installation details, turbidity testing during development and hydraulic conductivity testing of these wells
was documented in our 2019 letter report3 which is included as Attachment 1 to this report.
Figure 1 also shows the location of wells and piezometers from which samples were analyzed for As,
Fe, and Mn as documented in the 2010 site investigation report. Where two piezometers are shown at
the same location they were completed at different depths. Note that MW-3 will be removed as the result
of the construction of the I-540 corridor.
1 Eagle Resources, P.A.: Final_Groundwater_Baseline_Quality_Monitoring_Rev_020317
2 Eagle Resources, P.A.: Groundwater Mounding Analysis and Groundwater Quality Assessment, Wrenn Road Wastewater
Treatment Plant Spray Irrigation System, Garner, Wake County, North Carolina 10, 2010
3 Eagle Resources, P.A.: Documentation of Background Monitoring Well Installation and Testing, Letter Report to HDR
dated 11/08/19
1

aqi/e Pe5arcee
EXPLANATION
Wells and Piezometers
® Background Monitoring Well
S Compliance Monitoring Well
• Non -Compliance Monitoring Well
O Piezometer Nest - Two depths
• Piezometer
Field Boundaries
Active
Closed owing to 1-540 impacts
Property Boundaries (Wake County GIS)
500 0 500 1,000 1,500 2,000 Ft
Figure 1.-- Location of compliance and background wells and wells and piezometers sampled for the 2010 report.
2

tale Pescces
Sampling of Background and Compliance Wells
The monitoring plan recommended that the background and compliance wells (MW-B3, MW-B8 and
MW-B9) be sampled bi-monthly for one year following the installation and development of the new
wells. The sampling was to follow the recommended procedure for low flow purging and field analysis
for pH, conductivity, turbidity and temperature. Samples taken were to be analyzed in the City of Raleigh
Public Utilities Department (CORPUD) laboratory for As, Fe and Mn. One duplicate sample was to be
taken from a randomly selected background well each sampling round.
CORPUD staff obtained the samples from the background and compliance wells using the protocol
recommended in the monitoring plan and submitted the samples to the CORPUD laboratory. The results
of these analyses are summarized in Table 1 and the sampling reports are included as Attachment 2 to
this report. Note that duplicate analyses are only available for the last three sampling rounds (8/20/20,
11/4/20 and 3/10/21).
Table 2 shows the values for As, Fe, and Mn from Tables 8 and 9 of the 2010 report.
Constituent
Date
MW-B3
MW-B8
MW-B9
PMW-1
PMW-2
PMW-3
PMW-4
PMW-1 Dup
ug/I
ug/I
ug/1 _
ug/I
ug/I
ug/I
ug/I
ug/I
As
11/5/19
<10
<10
<10
<10
<10
<10
<10
ns
1/17/20
<10
ns
ns
<10
<10
<10
<10
ns
3/12/20
<10
<10
<10
<10
<10
<10
<10
ns
4/14/20
<10
0
0
0
ns
ns
<10
ns
7/8/20
<10
<10
<10
ns
ns
ns
ns
ns
8/20/20
<10
ns
na
<10
<10
<10
<10
<10
11/4/20
<10
<10
<10
<10
<10
<10
<10
<10
3/10/21
<5
ns
ns
<5
<5
<5
<5
<5
Fe
11/5/19
180
76
82
<60
<60
199
172
ns
1/17/20
98
ns
ns
<60
<60
<60
68
ns
3/12/20
<60
<60
89
<60
<60
141
<60
ns
4/14/20
65
ns
ns
<60
<60
<60
<60
ns
7/8/20
234
<60
166
ns
ns
ns
ns
ns
8/20/20
118
ns
ns
<60
<60
482
69
<60
11/4/20
301
<60
135
<60
72
73
<60
<60
3/10/21
108
ns
ns
97
ns
ns
ns
132
Mn
11/5/19
<50
<50
<50
90
<50
<50
134
ns
1/17/20
<50
ns
ns
74
<50
<50
<50
ns
3/12/20
<50
<50
<50
64
<50
<50
88
ns
4/14/20
<50
ns
ns
70
<50
<50
96
ns
7/8/20
<50
<50
<50
ns
ns
ns
ns
ns
8/20/20
<50
ns
ns
88
<50
<50
123
90
11/4/20
<50
<50
<50
59
<50
<50
88
61
3/10/21
<10
ns
ns
71
16
176
71
71
Notes: ns = no sample collected.
Table 1.-- Results of laboratory analyses for As, Fe, and Mn from the background and compliance wells sampled in 2019 and 2020.
3

Well
As
Fe
Mn
Unfiltered
Filtered
Unfiltered
Filtered
Unfiltered
Filtered
Round 1
Round 2
Round 2
Round 1
Round 2
Round 2
Round 1
Round 2
Round 2
ug/I
ug/I
ug/I
ug/I
ug/I
ug/I
ug/I
ug/I
ug/I
MW-1
42
8
<50
11742
4157
16
1067
220
26
MW-2
8
ns
ns
6369
ns
ns
628
ns
ns
MW-3
8
<50
<50
42
2497
39
371
ns
101
PZ-1
68
10
<50
3834
799
130
ns
1812
1676
PZ-2
61
11
<50
11694
2324
12
ns
443
91
PZ-3
9
ns
ns
3024
ns
ns
ns
ns
ns
PZ-4
24
<50
<50
26276
921
78
4432
339
331
PZ-5
82
<50
<50
30202
153
8
4114
52
43
PZ-6
24
<50
<50
69147
28581
22710
561
1628
1968
PZ-7
111
6
<50
23603
1709
77
2163
144
47
PZ-8
61
<50
<50
31936
272
17
3160
21
19
PZ-9
24
ns
ns
6921
ns
ns
3460
ns
ns
PZ-10
16
<50
<50
6958
578
22
3238
106
85
PZ-11
<50
ns
ns
1406
ns
ns
428
ns
ns
PZ-12
31
<50
<50
10303
512
38
842
38
32
PZ-14
ns
ns
ns
1523
ns
ns
553
ns
ns
PZ-15
ns
ns
ns
684
ns
ns
20
ns
ns
PZ-16
6
ns
ns
2388
ns
ns
250
ns
ns
PZ-17
16
ns
ns
2294
ns
ns
ns
ns
ns
PZ-18
42
<50
<50
6160
606
103
334
37
51
PZ-19
6
ns
ns
3140
ns
ns
220
ns
ns
ns = no sample collectred
Table 2.-- Results of laboratory analyses for As, Fe, and Mn from wells and piezometers reported in the 2010 report.
Data Analysis
Because all the values for As were below the method detection limit of 10 µg/1 for all samples, no statistical
analysis was performed for this constituent. To perform the analyses on Fe and Mn using all values from
the background samples that were less than the laboratory reported detection limits (10 µg/1 for Mn and
60 µg/1 for Fe) value of one (1) µg/l less that the limits was assigned (49 µg/1 for Mn and 59 µg/1 for Fe).
To answer the three questions posed previously, the concentrations of As, Fe, and Mn were compared by:
• Examination of plots of their log probability distributions; and
• Using One -Way Analysis of Variance (ANOVA)
Both statistical measures were computed using Microsoft ExcelTM
Probability Plots
The cumulative probability distributions of the log -transformed (ln or log base e) for Fe and Mn for the
background samples (compliance wells plus background wells), for the 2010 unfiltered samples and for
the 2010 filtered samples were computed and plotted for visual comparison.
Figure 2 shows the probability curves for Fe in the background samples and for the 2010 unfiltered
samples. This comparison shows that the Fe samples from the 2010 report are not from the same
4

eaie &mime
population as the background samples. Fe concentrations for both sets of samples are approximately log -
normally distributed based on the apparent fit of the curves to the data points.
1.0
0.9
0.8
▪ 0.7
to • 0.6
0
0.5
0.4
0.3
0.2
0.1
0.0
Fe All 2020 & 2021 and 2010 Unfiltered
• •
L
a
i
■
• In Fe 2020& 2021
Dist In Fe 2020 & 2021
—
—Norm
• In Fe 2010, unriltered
Norm Dist In Fe 2010
• In Fe2LStandard
—
I I I
0 2 4 6
In(Fe, ug/l)
8
10
12
14
Figure 2.-- Cumulative probability plots for the log -transformed concentrations of Fe for background samples and 2010 report unfiltered
samples.
Figure 3 shows the probability curves for Fe in the background samples and for the 2010 filtered samples.
This comparison shows that the filtered Fe samples from the 2010 report are closer to the same population
as the background samples but still probably not equal. Fe concentrations for both sets of samples are
approximately log -normally distributed based on the apparent fit of the curves to the data points.
5

1.0
0.9
0.8
. ' 0.7
2
- 0.6
0
L
0.5
0.4
0.3
0.2
0.1
0.0
Fe All 2020 & 2021 and 2010 Filtered
• •
• • •
• ....•.
• s s s
•
•
•
•
.
•
In Fe 2020 & 2021
Dist In Fe 2020 & 2021
In Fe 2010, filtered
Dist In Fe 2010
In Fe2LStandard
-Norm
•
-Norm
•
I I I
0 2 4 6
In(Fe, ug/I)
Figure 3.-- Cumulative probability plots for concentrations of Fe for background samples and 2010 report filtered samples.
8
10
12
14
Figure 4 shows the probability curves for Fe in the background samples from the new background wells
and from the compliance wells. This comparison shows that Fe from the compliance wells and from the
new wells are from the same population and therefore can be pooled. Because the distributions for the
pooled samples for Fe are less than the 2L standard, the 2L standard of 300 1.1,g/1 should be used for
compliance purposes to establish the site -specific background value of Fe concentrations for both sets of
samples are approximately log -normally distributed based on the apparent fit of the curves to the data
points.
6

1.0
0.9
0.8
0.5
0.4
0.3
0.2
0.1
0.0
Fe Compliance and Background Wells
• .
•
•
•
•
•
■
• In FeComplianceWells
Dist In Fe Compliance Wells
Wells
Dist In Fe Background Wells
L Standard
-Norm
• In Fe Background
-Norm
• In Fe 2
2
3
4 5
In(Fe, ugil)
6
7
Figure 4.-- Cumulative probability plots for concentrations of Fe in compliance wells and new background wells.
8
Figure 5 shows the probability curves for Mn in the background samples and for the 2010 unfiltered
samples. This comparison shows that the Mn samples from the 2010 report are not from the same
population as the background samples. Mn concentrations for both sets of samples are approximately
log -normally distributed based on the apparent fit of the curves to the data points.
1.0
0.9
0.8
0.7
n 0.6
0
a
0.5
0.4
0.3
0.2
0.1
0.0
Mn All 2020 & 2021 and 2010 Unfiltered
•
•
•
•
•
• InMn2020&2021 —
In
—Norm Dist Mn 2020 & 2021
•
• In Mn2010, unfiltered
In
—Norm Dist Mn2010 _
• In Mn2L Standard
__
I I I I
0 1 2 3 4 5
In(Mn), ug/I
6
7
8
9
10
Figure 5.-- Cumulative probability plots for concentrations of Mn for background samples and 2010 report filtered samples.
7

Figure 6 shows the probability curves for Mn in the background samples and for the 2010 filtered
samples. This comparison shows that the filtered Mn samples from the 2010 report are closer to the same
population as the background samples but still probably not equal. Mn concentrations for both sets of
samples are approximately log -normally distributed based on the apparent fit of the curves to the data
points.
1.0
0.9
0.8
0.7
0.6
L
d
0.5
0.4
0.3
0.2
0.1
0.0
Mn All 2020& 2021 and 2010 Filtered
•
• •
•
• •
•
•
•
•
• In
Mn2020 &2021
Dist In Mn2020
Mn 2010, filtered
Dist In Mn2010
Mn2LStandard
Norm
• In
-Norm
• In
•
--
1 1 1 1
0 1 2 3 4 5
In(Mn), ug/I
6
7
8
9
10
Figure 6.-- Cumulative probability plots for concentrations of Mn for background samples and 2010 report filtered samples.
Figure 7 shows the probability curves for Mn in the background samples from the new background wells
and from the compliance wells. This comparison shows that Mn from the compliance wells and from the
new wells are approximately from the same population but the compliance well data is skewed by all
being at the detection limit of 50 1.1g/1. Mn concentrations for both sets of samples are approximately
log -normally distributed based on the apparent fit of the curves to the data points.
The mean of the distributions for Mn when all data from the background and compliance wells are
considered is less than the 2L standard because of the large number of values less than the detection
concentration of 50 µg/1. Therefore, if the data from all of these wells is considered, the 21 standard of
50 µg/1 should be used for compliance purposes.
However, if only PMW-1 and PMW-4 are used to establish the site -specific background concentration of
Mn, there is statistical support for increasing it. The mean Mn value for all samples from these two wells
is 86 µg/1 and the standard deviation is 22 µg/1. If only these two wells are used, it is recommended that
the site -specific background concentration be set at 80 µg/1.
The large number of non -detect concentrations of Mn in the compliance wells is likely the result of dilution
by historical irrigation applied to their up -gradient fields. The non -detect values of Mn in PMW-2 and
PMW-3, which are located cross -gradient from all sprayfields, is likely the result of dilution from surface
runoff and flow in the stream located between them and the sprayfields.
8

1.0
0.9
0.8
0.7
si cv
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Mn Compliance and Background Wells
l
••
•
r.
r
.
• In MnComp liance Wells
Dist In Mn Compliance Wells
-Norm
• In Mn Background Wells
Norm Dist In Mn Ba Wells
ckg ro and
• In Mn2L Standard
2 3 4 5
In(Mn), ug/I
Figure 7.-- Cumulative probability plots for concentrations of Mn from compliance and new background wells.
6
7
8
Analysis of Variance
One-way Analysis of Variance (ANOVA) on the log -transformed values to further assess whether the new
background results from the compliance and background wells are from the same population as the 2010
samples. The analyses were conducted using the Data Analysis Package for Microsoft ExcelTM
Table 3 shows the ANOVA for Fe between the background samples and the unfiltered 2010 samples.
Because the F-statistic value of 8.85 is greater than the Fcrit value of 3.96, the samples are not from the
same population, consistent with the probability plot analysis.
Fe Background +Compliance Wells vs 2010 Unfiltered Samples
Anova: Single Factor Alpha = 0.01
Groups Count Sum Average Variance
In Fe Background Samples
46 237.64 5.17 29.83
38 322.25 8.48 20.95
In Fe2010 Unfiltered Samples
ANOVA
Source of Variation SS df MS F P-value F crit
Between Groups
228.5736
1
228.57
8.85
0.00
3.96
Within Groups
2117.4
82
25.82
Total 2345.973 83
Table 3.-- One-way ANOVA comparing the 2020 background values for Fe to the values for unfiltered samples from 2010.
9

eajle ie:AGir e5
Table 4 shows the ANOVA for Fe between the background samples and the filtered 2010 samples.
Because the F-statistic value of 0.14 is less than the Fcrit value of 4.00, the samples are from the same
population, consistent with the probability plot analysis and may be pooled.
Fe Background +Compliance Wells vs 2010 Filtered Samples
Anova: Single Factor Alpha = 0.01
Groups
Count
Sum
Average
Variance
In Fe Background Samples
46
237.64
5.17
29.83
In Fe2010 Filtered Samples
17
79.05
4.65
9.27
ANOVA
Source of Variation
SS
df
MS
F
P-value
F crit
Between Groups
3.30
1
3.30
0.14
0.71
4.00
Within Groups
1490.62
61
24.44
Total
1493.93
62
Table 4.-- One-way ANOVA comparing the 2020 background values for Fe to the values for filtered samples from 2010.
Table 5 shows the ANOVA for Fe between the samples from the new background wells and the
compliance wells for the 2019-2020 background sampling period. Because the F-statistic value of 2.11is
less than the Fcrit value of 4.11, the samples are from the same population, consistent with the probability
plot analysis and may be pooled.
Fe Background Wells vs Compliance Wells
Anova: Single Factor Alpha = 0.01
Groups
Count
Sum
Average
Variance
In Fe Compliance Wells
12
54.93
4.58
0.34
In Fe Background Wells
26
111.98
4.31
0.26
ANOVA
Source of Variation
SS
df
MS
F
P-value
F crit
Between Groups
0.60
1
0.60
2.11
0.16
4.11
Within Groups
10.27
36
0.29
Total
10.87
37
Table 5.-- One-way ANOVA comparing the 2020 background values for Fe from the compliance wells and the new background wells.
Table 6 shows the ANOVA for Mn between the background samples and the unfiltered 2010 samples.
Because the F-statistic value of 2.36 is slightly less than the Fcrit value of 3.97, the samples are from the
same population, consistent with the probability plot analysis.
10

Ea�eeesarces
Mn Background +Compliance Wells vs 2010 Unfiltered Samples
Anova: Single Factor Alpha =0.01
Groups
Count
Sum
Average
Variance
In Mn Background
46
220.72
4.80
30.17
In Mn 2010 Unfiltered
33
216.32
6.56
18.07
ANOVA
Source of Variation
SS
df
MS
F
P-value
Fcrit
Between Groups
59.32
1
59.32
2.36
0.13
3.97
Within Groups
1936.00
77
25.14
Total
1995.32
78
Table 6.-- One-way ANOVA comparing the 2020 background values for Mn to the values for unfiltered samples from 2010.
Table 7 shows the ANOVA for Mn between the background samples and the filtered 2010 samples.
Because the F-statistic value of 1.93 is less than the Fcrit value of 4.05, the samples are from the same
population, consistent with the probability plot analysis and may be pooled. The differences between the
two populations are the result of assigning a value of 49 µg/1. to samples that were reported to be below
the detection limit of 50 µg/l.
Mn Background +Compliance Wellsys 2010 Filtered Samples
Anova: Single Factor Alpha = 0.01
Groups
Count
Sum
Average
Variance
In Mn Background
33
216.32
6.56
18.07
In Mn 2010 Filtered
16
79.48
4.97
5.66
ANOVA
Source of Variation
SS
df
MS
F
P-value
Fcrit
Between Groups
27.1682947
1
27.17
1.93
0.17
4.05
Within Groups
663.187462
47
14.11
Total
690.355756
48
Table 7.-- One-way ANOVA comparing the 2020 background values for Mn from the compliance wells and the new background wells.
Table 8 shows the ANOVA for Mn between the samples from the new background wells and the
compliance wells for the 2019-2020 background sampling period. Because the F-statistic value of 5.95
is close to the Fcrit value of 4.09, the samples probably are from the same population, consistent with the
probability plot analysis and may be pooled. The differences between the two populations are the result
of assigning a value of 49 µg/1 to samples that were reported to be below the detection limit of 50 µg/1.
11

Mn Background vs Compliance Wells
Anova: Single Factor Alpha = 0.01
Groups
Count
Sum
Average
Variance
In Mn Compliance Wells
11
42.81
3.89
0.00
In Mn Background Wells
30
123.77
4.13
0.10
ANOVA
Source of Variation
SS
df
MS
F
P-value
F crit
Between Groups
0.44
1
0.44
5.95
0.02
4.09
Within Groups
2.89
39
0.07
Total
3.33
40
Table 8.-- One-way ANOVA comparing the values for Mn from the compliance wells vs. the new background wells.
Pooling of new samples and the 2010 samples
The monitoring plan recommended that if samples from the background sampling were statistically from
the same population as those from the 2010 study that they should be pooled to determine if they should
be used to set site -specific background concentrations for Fe and Mn.
Because the statistical analyses in the foregoing show that the 2011 unfiltered sample results for both Fe
and Mn are not from the same population as those from the background monitoring program samples to
date the 2011 unfiltered samples should not be used in an assessment of a site -specific background
standard for either Fe or Mn.
The filtered samples from 2011 for both Fe and Mn appear to approximately from the same population
as the background monitoring program samples. This is likely because purging and sampling protocol
used for the background program accomplished the same reduction in turbidity and suspended fine
particulate matter as filtration did for the 2010 samples. Because filtration of samples is not included in
the accepted sampling and analysis protocol by NC DEQ, it is recommended that the 2010 filtered
sample data not be used in assessing site -specific background standards for either constituent.
12

ea* Pesarces
Time Trends
The monitoring plan recommended sampling the new background wells for one year on the same
schedule used for the compliance wells (March, July, and November) to evaluate any time trends
in As, Fe, Mn to consider in compliance assessments. The values plotted and analyzed below are
not log -transformed as the conclusions reached regarding the significance of the slope of the
trend lines is not affected by the transformation. Plots are only included for those wells in
which the number of sample results greater than the detection limits for either Fe or Mn provided
for a meaningful analysis.
Figure 8 and Table 9 show that there is no statistically significant increase in Fe in MW-B3
because the F -statistic value of 0.42 shown in Table 9 is less than the Significance F value of
0.54.
[Fe] & [Mn], ug/I
350
300
250
200
150
100
50
0
0
Fe and Mn in MW-B3
I I
•
• Fe MW-B3
Mn
• MW-B3
Linear (Fe MW-B3)
Linear (Mn MW-B3)
•
•
..................
•
•
•
_ _
•
....•• ......
♦ •
•
•
100 200 300
Days since 11/01/2019
Figure 8.-- Time trend in Fe and Mn in compliance well MW-B3.
400
500
Regression Statistics
ANOVA
Multiple R
0.257
RSquare
0.066
df SS MS F SignificanceF
Adjusted RSquare
-0.090
Regression
1.00
3406.05
3406.05
0.42
0.54
Standard Error
89.608
Residual
6.00
48177.82
8029.64
Observations
8
Total
7.00
51583.88
Coefficients Standard Error tStat P-value Lower95% Upper95% Lower95.0% Upper95.0%
Intercept 114.84
56.59 2.03 0.09 -23.62 253.30 -23.62 253.30
0.211 0.65 0.541 -0.38 0.651 -0.38 0.65
X Variable 1 ` 0.14
Table 9.-- Regression analysis for the significance of the slope of the regression line for Fe in MW-B3.
13

Gre feces
Figure 9 and Table 10 show that there is a statistically significant increase in Fe in MW-B9
because the F -statistic value of 2.85 shown in Table 10 is greater than the Significance F value
of 0.23.
[Fe] & [Mn], ug/I
180
160
140
120
100
80
60
40
20
0
0
Fe and Mn in MW-B9
I I I
•
• Fe MW-B9
• Mn MW-B9
Linear (Fe MW-B9)
Linear (Mn MW-B9)
•
•..
•
•
••...
•
•
•
•
50 100 150 200 250 300 350 400
Days since 11/01/2019
Figure 9.-- Time trend in Fe and Mn in compliance well MW-B9.
Fein Compliance Well MW-B9
Regression Statistics
ANOVA
Multiple R
0.767
R Square
0.588
df SS MS F Significance F
Adjusted RSquare
0.381
Regression
1.00
2778.98
2778.98
2.85
0.23
Standard Error
31.233
Residual
2.00
1951.02
975.51
Observations
4
Total
3.00
4730.00
Coefficients Standard Error tStat P-value Lower95% Upper95% Lower95.0% Upper95.0%
Intercept 81.32 26.76 3.04 0.09 -33.82 196.46 -33.82 196.46
Days 0.19 0.12 1.69 0.23 -0.30 0.69 -0.30 0.69
Table 10.-- Regression analysis for the significance of the slope of the regression line for Fe in MW-B9.
Figure 10 and Table 11 show that there is a statistically significant increase in Fe in new
background well PMW-3 because the F -statistic value of 3.31 shown in Table 11 is less than
the Significance F value of 0.13.
14

anan
700
600
500
400
300
200
100
0
Fe and Mn in PMW-3
I I
•
•
Fe PMW-3
MnPMW-3
i
0
100
200 300 400
Days since 11101j2019
Figure 10.-- Time trend in Fe and Mn in new background well PMW-3.
500
600
ea* Pesarces
Regression Statistics
ANOVA
MultipleR
0.6312
R Square
0.3985
df SS MS F Significance F
Adjusted R Square
0.2782
Regression
1
116812.66
116812.66
3.31
0.13
Standard Error
187.80
Residual
5
176343.05
35268.61
Observations
7
Total
6
293155.71
Coefficients Standard Error tStat P-value Lower95% Upper95% Lower95.0% Upper95.0%
Intercept 54.42 120.03 0.45 0.67 -254.12 362.96 -254.12 362.96
X Variable 1 0.80 0.44 1.82 0.13 -0.33 1.94 -0.33 1.94
Table 11.-- Regression analysis for the significance of the slope of the regression line for Fe in PMW-3.
Figure 11 and Table 12 show that there is a statistically significant decrease in Fe in new
background well PMW-4 because the F -statistic value of 3.14 shown in Table 12 is greater than
the Significance F value of 0.13. Although samples from PMW-4 showed values of Mn greater
than the detection limit, there is no significant time trend in these values because the F -statistic
value of 0.27 shown in Table 13 is less than the Significance F value of 0.62.
15

[Fe] & [Mn], ug/I
200
180
160
140
120
100
80
60
40
20
0
0
Fe and Mn in PMW-4
I
• Fe PMW-4
•
• Mn PMW-4
Linear (Fe PMW-4)
Linear (Mn PMW-4)
•
•
..._
_...,,.......
.:t....•.........
................................�..........................
•
•.*.
•
•
• •..........•
•
100 200 300
Days since 11/01/2019
Figure 11.-- Time trend in Fe and Mn in new background well PMW-4.
400
500
ea* Pesarces
Regression Statistics
ANOVA
Multiple R
0.6213
RSquare
0.3860
df SS MS F SignificanceF
Adjusted RSquare
0.2632
Regression
1
4216.53
4216.53
3.14
0.14
Standard Error
36.6256
Residual
5
6707.19
1341.44
Observations
7
Total
6
10923.71
Coefficients Standard Error tStat P-value Lower95% Upper95% Lower95.0% Upper95.0%
Intercept
109.90
23.41
4.69
0.01
49.72
170.07
49.72
170.07
X Variable 1
-0.15
0.09
-1.77
0.14
-0.37
0.07
-0.37
0.07
Table 12.-- Regression analysis for the significance of the slope of the regression line for Fe in PMW-4.
Regression Statistics
ANOVA
MultipleR
0.2278
RSquare
0.0519
df
SS
MS
F
SignificanceF
Adjusted RSquare
-0.1377
Regression
1
262.65
262.65
0.27
0.62
Standard Error
30.9735
Residual
5
4796.78
959.36
Observations
7
Total
6
5059.43
Coefficients
Standard Error
tStat
P-value
Lower95%
Upper95%
Lower95.0%
Upper95.0%
Intercept
101.07
19.80
5.11
0.00
50.18
151.95
50.18
151.95
X Variable 1
-0.04
0.07
-0.52
0.62
-0.23
0.15
-0.23
0.15
Table 13.-- Regression analysis for the significance of the slope of the regression line for Mn in PMW-4.
16

ea* Pesarces
Conclusions
The data from the 2010 study for Fe and Mn in groundwater samples is not statistically from the
same population as that from the data from the compliance and new background wells and
should not be used in assessing site -specific background standards.
The data from the background sampling program to date show that the mean and standard
deviation of the concentrations for Fe are lower than the 2L groundwater standard of 300 µg/1
respectively. Consequently, the 2L standards should continue to be used as the values for
compliance monitoring for Fe.
Because there appears to be statistically significant changes over time since the start of the
compliance sampling in November of 2019 in Fe concentrations in some of the compliance and
background wells, it is recommended that these trends be assessed on an annual basis to
determine if there is a basis for increasing the Fe standard for the site to a value greater than the
2L standard.
Concentrations of As in the compliance and background wells have all been less than the 2L
standard of 10 µg/1 and therefore, that value should continue to be used as the value for
compliance monitoring.
This update, which includes samples taken on 3/10/2021, shows that the average Mn
concentration 66 µg/1 is greater than the 2L standard of 50 µg/1. Therefore, it is recommended
that the site -specific background concentration for Mn be set at 66 µg/1.
The large number of non -detect concentrations of Mn in the compliance wells is likely the result
of dilution by historical irrigation applied to their up -gradient fields. The non -detect values of Mn
in PMW-2 and PMW-3 which are located cross -gradient from all sprayfields is likely the result of
dilution from surface runoff to and surface flow in the stream located between them and the
sprayfields.
17

ea/e►('esarces
Attachment 1 Approved Background Sampling Program
The following steps are recommended to implement the determination of background
concentrations of Fe and Mn at the Wrenn Road Site:
1. Install and develop the five (5) new background monitoring wells as recommended
herein;
2. Sample the background and compliance wells bi-monthly for six (6) months following
the installation and development of the new wells. The sampling should follow the
recommended low -flow purging, and field analysis for pH, Conductivity, Turbidity, and
Temperature. Samples taken should be analyzed in the CORPUD laboratory for As, Fe
and Mn This will provide a background sample size of 15 (5 wells x 3 samples) for each
constituent. One duplicate should be taken from a randomly selected background well
each sampling round;
3. Prepare probability plots of the 15 sample results for each constituent using the log
transform of the raw values; and visually compare to the plots for the 2010 samples;
4. Conduct One-way Analysis of Variance (ANOVA) on the log -transformed values to
assess whether the new background results are from the same population as the 2010
samples;
5. If the ANOVA shows that the new and 2010 samples are from the same population, pool
both to define the background statistics to use in compliance monitoring; or
6. If the ANOVA shows that the new and 2010 samples are not from the same population,
use only the new samples to define the background statistics to use in compliance
monitoring; and
Sample the new background wells for one year on the same schedule used for the compliance
wells (March, July, and November) to evaluate any time trends in As, Fe, Mn to consider in
compliance assessments. Log transformation should be applied to all these data.
18

Attachment 2 Sampling Reports from CORPUD
em/e►('esarces
19

City of Raleigh
Wrenn Road Groundwater Monitoring Plan
Permit No. WQ0002708
Notes:
Before collecting samples, low flow well purging should continue until turbidity<10 NTU or vary no morethan 10%
Before collecting samples, pH and water temperature should be stable
One duplicate should be collected from one ofthe background wells for each sampling round
Try to usethe same equipment during sampling, and note when alternate equipment is used to help account for a difference in results
Month
November 2019Background
MW-B3
PMW-1
PMW-2
PMW-3
PMW-4
Statistics
Sampled By
D. Godfrey
R. Tart
D. Godfrey
R. Tart
D. Godfrey
Date
11/5/19
11/21/19
11/21/19
11/21/19
11/21/19
Time
8:05
11:18
8:40
12:23
12:10
Daily Weather Condition
Clear/Cool/Sunny
Field Data
Depth to water
21.65'
24'
8
6'
21.9'
Total well depth
30'
43'
20'
16'
74'
Volumeofwater purged before
sampling (gal)
4.25 gal
9.31 gal
6 gal
4.57 gal
25.5 gal
Turbidity (NTU)
0.87
0.48
1.86
1.58
5.08
pH, units
5.23
5.75
5.3
6.03
5.97
Temperature, °C
16.6
16.6
16.8
16.9
17.6
Lab Data
Conductivity (umhos/cm)
45.9
98.9
69.6
129.8
126.2
Iron (pg/L)
180
<60
<60
199
172
Manganese(pg/L)
<50
90
<50
<50
134
Arsenic (pg/L)
<10
<10
<10
<10
<10

CITY OF RALEIGH
EM JOHNSON WATER PLANT LABORATORY
Wrenn Road Spray Irrigation Facility
Permit No. W00002708
Wells Monitoring Data Results
Month: November
Year: 2019
Location: MW-3
Collection Date
Parameter
Results
Units of Measure
Daily Max
Limits
05-Nov-19
Arsenic
<10
ug/L
10
05-Nov-19
Conductivity
45.9
umhos/cm
05-Nov-19
Iron
180
ug/L
300
05-Nov-19
Manganese
<50
ug/L
50
05-Nov-19
pH
5.23
su
6.5 - 8.5
05-Nov-19
Temperature
16.6
C
05-Nov-19
Turbidity
0.87
NTU
05-Nov-19
Arsenic
<10
ug/L
10
05-Nov-19
Chloride
<10
mg/L
250
05-Nov-19
Conductivity
45.9
umhos/cm
05-Nov-19
DO
2.39
mg/L
05-Nov-19
Fecal MPN
0
MPN/100 ml
05-Nov-19
Nitrate
0.8
mg/L
10
05-Nov-19
pH
5.23
su
6.5 - 8.5
05-Nov-19
Sulfate
<10
ppm
250
05-Nov-19
Total Dissolved Solids @ 180 degrees
86
mg/L
500
05-Nov-19
Temperature
16.6
C
05-Nov-19
TOC
<1.0
mg/L
Location: MW-8
Collection Date
Parameter
Results
Units of Measure
Daily Max
Limits
05-Nov-19
Arsenic--10
ug/L
10
05-Nov-19
Chloride
23.07
mg/L
250
05-Nov-19
Conductivity
94.9
umhos/cm
05-Nov-19
DO
2.86
mg/L
05-Nov-19
Fecal MPN
0
MPN/100 ml
05-Nov-19
Iron
76
ug/L
300
05-Nov-19
Manganese
<50
ug/L
50
05-Nov-19
Nitrate
0.37
mg/L
10
05-Nov-19
pH
5.07
su
6.5 - 8.5
05-Nov-19
Sulfate
<10
ppm
250
05-Nov-19
Total Dissolved Solids @ 180 degrees
142
mg/L
500
05-Nov-19
Temperature
15.5
C
05-Nov-19
TOC
<1.0
mg/L
05-Nov-19
Turbidity
0.77
NTU
Location: MW-9
Collection Date
Parameter
Results
Units of Measure
Daily Max
Limits
05-Nov-19
Arsenic
<10
ug/L
10
05-Nov-19
Chloride
27.66
mg/L
250
05-Nov-19
Conductivity
144.6
umhos/cm
05-Nov-19
DO
1.71
mg/L
05-Nov-19
Fecal MPN
0
MPN/100 ml
05-Nov-19
Iron
82
ug/L
300
05-Nov-19
Manganese
<50
ug/L
50
05-Nov-19
Nitrate
1.29
mg/L
10
05-Nov-19
pH
5.05
su
6.5 - 8.5
05-Nov-19
Sulfate
10.36
ppm
250
05-Nov-19
Total Dissolved Solids @ 180 degrees
172
mg/L
500
05-Nov-19
Temperature
17.4
C
05-Nov-19
TOC
<1.0
mg/L
05-Nov-19
Turbidity
1.52
NTU

City of Raleigh
Wrenn Road Groundwater Monitoring Plan
Permit No. WQ0002708
Notes:
Before collecting samples, low flow well purging should continue until turbidity<10 NTU or vary no morethan 10%
Before collecting samples, pH and water temperature should be stable
One duplicate should be collected from one of the background wells for each sampling round
Try to usethe same equipment during sampling, and note when alternate equipment is used to help account for a difference in results
Month
Januarv2020Background
MW-B3
PMW-1
PMW-2
PMW-3
PMW-4
Statistics
Sampled By
D. Godfrey
R. Tart
R. Tart
R. Tart
D. Godfrey
Date
1/17/20
1/17/20
1/17/20
1/17/20
1/17/20
Time
1002
1005
1049
818
1040
Daily Weather Condition
Partly Sunny, Cool
Field Data
Depth to water
19.1
23.8
7.4
5.6
20.5
Total well depth
30'
43'
20'
16'
74'
Volume of water purged before
sampling (gal)
4.75 gals
9.4 gals
6.1 gals
6.5 gals
27 gals
Turbidity (NTU)
1.3
0.98
0.48
1.06
2.04
pH, units
4.86
5.87
6.02
6.68
6.07
Temperature, °C
16.2
14
15.1
12.8
15.3
Lab Data
Conductivity (umhos/cm)
43
91.6
67.2
110.1
121.2
Iron (pg/L)
98
<60
<60
<60
68
Manganese(pg/L)
<50
74
<50
<50
<50
Arsenic (Ng/L)
<10
<10
<10
<10
<10

City of Raleigh
Wrenn Road Groundwater Monitoring Plan
Permit No. WQ0002708
Notes:
Before collecting samples, low flow well purging should continue until turbidity<10 NTU or vary no morethan 10%
Before collecting samples, pH and water temperature should be stable
One duplicate should be collected from one of the background wells for each sampling round
Try to usethe same equipment during sampling, and note when alternate equipment is used to help account for a difference in results
Month
March 2020Background
MW-B3
PMW-1
PMW-2
PMW-3
PMW-4
Statistics
Sampled By
D. Godfrey
D. Godfrey
R. Tart
R. Tart
D. Godfrey
Date
3/12/20
3/12/20
3/12/20
3/12/20
3/12/20
Time
1040
1206
750
1230
959
Daily Weather Condition
Cloudy, Cool
Field Data
Depth to water
19.1
20.85
7.5
5.3
16.2
Total well depth
30'
43'
20'
16'
74'
Volume of water purged before
sampling (gal)
5.5 gals
11 gals
7 gals
5.25 gals
28.5 gals
Turbidity (NTU)
0.78
1.31
0.53
3.49
1.76
pH, units
4.85
5.31
5.93
7.03
6.16
Temperature, °C
16.6
18.2
14.6
14.3
16.8
Lab Data
Conductivity (umhos/cm)
41.4
90.9
71.8
62.2
115.4
Iron (pg/L)
<60
<60
<60
141
<60
Manganese(pg/L)
<50
64
<50
<50
88
Arsenic (pg/L)
<10
<10
<10
<10
<10

CITY OF RALEIGH
EM JOHNSON WATER PLANT LABORATORY
Wrenn Road Spray Irrigation Facility
Permit No. WQ0002708
Wells Monitoring Data Results
Month: March
Year: 2020
I nra*inn• M\A/_2
Collection Date
Parameter
Results
Units of Measure
Daily Max
12-Mar-20
Arsenic
<10
ug/L
10
12-Mar-20
Chloride
<10
mg/L
250
12-Mar-20
Conductivity
41.4
umhos/cm
12-Mar-20
DO
3.11
mg/L
12-Mar-20
Fecal MPN
0
MPN/100 ml
12-Mar-20
Iron
<60
ug/L
300
12-Mar-20
Manganese
<50
ug/L
50
12-Mar-20
Nitrate
0.68
mg/L
10
12-Mar-20
pH
4.85
pH
6.5 - 8.5
12-Mar-20
Sulfate
<10
ppm
250
12-Mar-20
Total Dissolved Solids @ 180 degrees C
39
mg/L
500
12-Mar-20
Temperature
16.6
C
12-Mar-20
TOC
<0.5
mg/L
12-Mar-20
Turbidity
0.78
NTU
• nn'ni_
Collection Date
Parameter
Results
Units of Measure
Daily Max
12-Mar-20
Arsenic
<10
ug/L
10
12-Mar-20
Chloride
17.8
mg/L
250
12-Mar-20
Conductivity
77
umhos/cm
12-Mar-20
DO
5.20
mg/L
12-Mar-20
Fecal MPN
0
MPN/100 ml
12-Mar-20
Iron
<60
ug/L
300
12-Mar-20
Manganese
<50
ug/L
50
12-Mar-20
Nitrate
0.44
mg/L
10
12-Mar-20
pH
6.33
pH
6.5 - 8.5
12-Mar-20
Sulfate
<10
ppm
250
12-Mar-20
Total Dissolved Solids @ 180 degrees C
62
mg/L
500
12-Mar-20
Temperature
15.5
C
12-Mar-20
TOC
<0.5
mg/L
12-Mar-20
Turbidity
0.56
NTU
Collection Date
Parameter
Results
Units of Measure
Daily Max
12-Mar-20
Arsenic
<10
ug/L
10
12-Mar-20
Chloride
11.41
mg/L
250
12-Mar-20
Conductivity
76.9
umhos/cm
12-Mar-20
DO
3.14
mg/L
12-Mar-20
Fecal MPN
0
MPN/100 ml
12-Mar-20
Iron
89
ug/L
300
12-Mar-20
Manganese
<50
ug/L
50
12-Mar-20
Nitrate
0.54
mg/L
10
12-Mar-20
pH
7.02
pH
6.5 - 8.5
12-Mar-20
Sulfate
<10
ppm
250
12-Mar-20
Total Dissolved Solids @ 180 degrees C
54
mg/L
500
12-Mar-20
Temperature
16.0
C
12-Mar-20
TOC
0.7404
mg/L
12-Mar-20
Turbidity
3.87
NTU

City of Raleigh
Wrenn Road Groundwater Monitoring Plan
Permit No. WQ0002708
Notes:
Before collecting samples, low flow well purging should continue until turbidity<10 NTU or vary no morethan 10%
Before collecting samples, pH and water temperature should be stable
One duplicate should be collected from one of the background wells for each sampling round
Try to usethe same equipment during sampling, and note when alternate equipment is used to help account for a difference in results
Month
April 2020 Compliance
MW-B3
PMW-1
PMW-2
PMW-3
PMW-4
Monitoring
Sampled By
D. Godfrey
R. Tart
R. Tart
R. Tart
D. Godfrey
Date
4/14/20
4/14/20
4/14/20
4/14/20
4/14/20
Time
1107
1015
830
1145
1028
Daily Weather Condition
Sunny, Clear 60s
Field Data
Depth to water
19'
20.9'
7.7'
5.7'
16.4'
Total well depth
30'
43'
20'
16'
74'
Volumeofwater purged before
sampling (gal)
5.5 Gallons
10.8 Gallons
6.5 Gallons
5.0 Gallons
28.25 Gallons
Turbidity (NTU)
0.44
0.39
0.23
0.46
1.61
pH
4.82
7.15
7.32
6.27
6.05
Temperature
17.2
17.6
14.8
15.5
17
Lab Data
Conductivity (umhos/cm)
39.8
92.2
68.8
116.4
110.8
Iron (pg/L)
65
<60
<60
<60
<60
Manganese(pg/L)
<50
70
<50
<50
96
Arsenic (Ng/L)
<10
<10
<10
<10
<10

Month: July
Year: 2020
• _
CITY OF RALEIGH
EM JOHNSON WATER PLANT LABORATORY
Wrenn Road Spray Irrigation Facility
Permit No. WQ0002708
Wells Monitoring Data Results
Collection Date
Parameter
Units of Measure
Results
Daily Max
7/8/2020
pH
su
5.19
6.5 - 8.5
7/8/2020
Fecal Coliform
col/100 ml
0
7/8/2020
Total Dissolved Solids @ 180°C
mg/I
38
500
7/8/2020
Total Organic Carbon
mg/I
<0.5
7/8/2020
Chloride
mg/1
5.17
250
7/8/2020
Nitrate Nitrogen
mg/1
0.44
10
7/8/2020
Sulfate
mg/I
<5
250
7/8/2020
Iron
ug/I
234
300
7/8/2020
Manganese
ug/I
<50
50
7/8/2020
Arsenic
ug/I
<10
10
7/8/2020
Total Phosphorus
mg/1
<0.05
7/8/2020
Acrylamide
ug/I
<0.50
0.008
Collection Date
Parameter
Units of Measure
Results
Daily Max
7/8/2020
pH
su
5.35
6.5 - 8.5
7/8/2020
Fecal Coliform
col/100 ml
0
7/8/2020
Total Dissolved Solids @ 180°C
mg/I
55
500
7/8/2020
Total Organic Carbon
mg/I
<0.5
7/8/2020
Chloride
mg/I
17.9
250
7/8/2020
Nitrate Nitrogen
mg/I
0.02
10
7/8/2020
Sulfate
mg/I
<5
250
7/8/2020
Iron
ug/I
<60
300
7/8/2020
Manganese
ug/I
<50
50
7/8/2020
Arsenic
ug/I
<10
10
7/8/2020
Total Phosphorus
mg/I
<0.05
7/8/2020
Acrylamide
ug/I
<0.50
0.008
Collection Date
Parameter
Units of Measure
Results
Daily Max
7/8/2020
pH
su
5.32
6.5 - 8.5
7/8/2020
Fecal Coliform
col/100 ml
0
7/8/2020
Total Dissolved Solids @ 180°C
mg/I
71
500
7/8/2020
Total Organic Carbon
mg/I
1.01
7/8/2020
Chloride
mg/1
20.9
250
7/8/2020
Nitrate Nitrogen
mg/I
1.47
10
7/8/2020
Sulfate
mg/I
6.99
250
7/8/2020
Iron
ug/I
166
300
7/8/2020
Manganese
ug/I
<50
50
7/8/2020
Arsenic
ug/I
<10
10
7/8/2020
Total Phosphorus
mg/1
<0.05
7/8/2020
Acrylamide
ug/I
<0.50
0.008

City of Raleigh
Wrenn Road Groundwater Monitoring Plan
Permit No. WQ0002708
Notes:
Before collecting samples, low flow well purging should continue until turbidity<10 NTU or vary no morethan 10%
Before collecting samples, pH and water temperature should be stable
One duplicate should be collected from one of the background wells for each sampling round
Try to usethe same equipment during sampling, and note when alternate equipment is used to he p account for a difference in results
Month
August 2020 Comoliance
MW-B3
PMW-1
PMW-1 Dup
PMW-2
PMW-3
PMW-4
Monitoring
Sampled By
Roy Tart
Roy Tart
Roy Tart
Roy Tart
Roy Tart
Roy Tart
Date
8/20/20
8/20/20
8/20/20
8/20/20
8/20/20
8/20/20
Time
14:35
13:25
13:25
12:01
15:15
12:45
Daily Weather Condition
Cloudy 80°F
Field Data
Depth to water
20.3
22.8
22.8
9.8
6
19
Total well depth
30
43
43
20
30
74
Volume of water purged before
sampling (gal)
4.7
9.8
9.8
5.1
5
26
Turbidity (NTU)
0.9
0.68
0.68
1.46
1.69
1.5
pH
5.8
5.93
5.93
6.01
6.63
6.81
Temperature
18.5
19.1
19.1
20.7
19.8
19
Conductivity (umhos/cm)
111
94.5
96.7
73.3
43.5
124.5
Iron (pg/L)
118
<60
<60
<60
482
69
Manganese(pg/L)
<50
88
90
<50
<50
123
Arsenic (pglL)
<10
<10
<10
<10
<10
<10

City of Raleigh
Wrenn Road Groundwater Monitoring Plan
Permit No. WQ0002708
Notes:
Before collecting samples, low flow well purging should continue until turbidity<10 NTU or vary no morethan 10%
Before collecting samples, pH and water temperature should be stable
One duplicate should be collected from one ofthe background wells for each sampling round
Try to usethe same equipment during samp ing, and note when alternate equipment is used to help account for a difference in results
Month
November 2020 Compliance
MW-B3
PMW-1
PMW-1 Dup
PMW-2
PMW-3
PMW-4
Monitoring
Sampled By
D. Godfrey
D. Godfrey
D. Godfrey
D. Godfrey
D. Godfrey
D. Godfrey/E.
Batchelor
Date
11/4/20
11/4/20
11/4/20
11/4/20
11/4/20
11/4/20
Time
9:43
8:25
8:25
9:08
10:44
12:00
Daily Weather Condition
Clear 48 °C Clear 40 °C Clear 40 °C Clear 40 °C Clear 55 °C Clear 62 °C
Field Data
Depth to water
19.95
22.3
22.3
7.8
5.7
18.9
Total well depth
30'
43'
43'
20'
16'
74'
Volume of water purged before
sampling (gal)
5
10.25
10.25
6
5.25
27
Turbidity(NTU)
0.73
1.12
1.12
1.86
0.44
0.72
pH
4.79
5.32
5.32
5.08
5.65
5.87
Temperature
17.8
17
17
18.5
18.1
18.2
Conductivity (umhos/cm)
41.4
82
82.4
73.6
101.5
129.8
Iron )pg/L)
301
<60
<60
72
73
<60
Manganese(pg/L)
<50
59
61
<50
<50
88
Arsenic (pg/L)
<10
<10
<10
<10
<10
<10

CITY OF RALEIGH
EM JOHNSON WATER PLANT LABORATORY
Wrenn Road Sorav Irrieation Facility
Permit No. W00002708
Wells Monitorine Data Results
Month: November
Year: 2020
Location: MW-3
Collection Date
Parameter
Results
Units of Measure
Daily Max
04-Nov-20
Arsenic
<10
ug/L
10
04-Nov-20
Conductivity
41.4
umhos/cm
04-Nov-20
Iron
334
ug/L
300
04-Nov-20
Manganese
<50
ug/L
50
04-Nov-20
pH
4.79
su
6.5 - 8.5
04-Nov-20
Temperature
17.8
C
04-Nov-20
Turbidity
0.73
NTU
05-Nov-20
Arsenic
<10
ug/L
10
05-Nov-20
Chloride
6.073
mg/L
250
05-Nov-20
Conductivity
40.3
umhos/cm
05-Nov-20
DO
2.06
mg/L
05-Nov-20
Fecal MPN
0
MPN/100 ml
05-Nov-20
Iron
301
ug/L
300
05-Nov-20
Manganese
<50
ug/L
50
05-Nov-20
Nitrate
0.35
mg/L
10
05-Nov-20
pH
4.52
su
6.5 - 8.5
05-Nov-20
Sulfate
<5
ppm
250
05-Nov-20
Total Dissolved Solids (&, 180 degrees
41
mg/L
500
05-Nov-20
Temperature
17.2
C
05-Nov-20
TOC
<1.0
mg/L
05-Nov-20
Total Phosphorus
<0.04
mg/L
05-Nov-20
Turbidity
0.76
NTU
Collection Date
Parameter
Results
Units of Measure
Daily Max
05-Nov-20
Arsenic
<10
ug/L
10
05-Nov-20
Chloride
21.932
mg/L
250
05-Nov-20
Conductivity
91.4
umhos/cm
05-Nov-20
DO
3.78
mg/L
05-Nov-20
Fecal MPN
0
MPN/100 ml
05-Nov-20
Iron
<60
ug/L
300
05-Nov-20
Manganese
<50
ug/L
50
05-Nov-20
Nitrate
<0.04
mg/L
10
05-Nov-20
pH
4.69
su
6.5 - 8.5
05-Nov-20
Sulfate
<5
ppm
250
05-Nov-20
Total Dissolved Solids A 180 degrees
73
mg/L
500
05-Nov-20
Temperature
16.2
C
05-Nov-20
TOC
<1.0
mg/L
05-Nov-20
Total Phosphorus
<0.04
mg/L
05-Nov-20
Turbidity
0.88
NTU
•
Collection Date
Parameter
Results
Units of Measure
Daily Max
05-Nov-20
Arsenic
<10
ug/L
10
05-Nov-20
Chloride
22.576
mg/L
250
05-Nov-20
Conductivity
122.0
umhos/cm
05-Nov-20
DO
1.41
mg/L
05-Nov-20
Fecal MPN
0
MPN/100 ml
05-Nov-20
Iron
135
ug/L
300
05-Nov-20
Manganese
<50
ug/L
50
05-Nov-20
Nitrate
1.04
mg/L
10
05-Nov-20
pH
4.64
su
6.5 - 8.5
05-Nov-20
Sulfate
8.892
ppm
250
05-Nov-20
Total Dissolved Solids A 180 degrees
81
mg/L
500
05-Nov-20
Temperature
17.3
C
05-Nov-20
TOC
<1.0
mg/L
05-Nov-20
Total Phosphorus
<0.04
mg/L
05-Nov-20
Turbidity
5.97
NTU

City of Raleigh
Wrenn Road Groundwater Monitoring Plan
Permit No. WQ0002708
Notes:
Before collecting samples, low flow well purging should continue until turbidity<10 NTU or vary no morethan 10%
Before collecting samples, pH and water temperature should be stable
One duplicate should be collected from one of the background wells for each sampling round
Try to usethe same equipment during samp ing, and note when alternate equipment is used to help account for a difference in results
Month
March 2021 Compliance
MW-B3
PMW-1
PMW-1 Dup
PMW-2
PMW-3
PMW-4
Monitoring
Sampled By
D. Godfrey
D. Godfrey
D. Godfrey
D. Godfrey
D. Godfrey
D. Godfrey
Date
3/10/21
3/10/21
3/10/21
3/10/21
3/10/21
3/10/21
Time
7:50
8:50
8:50
9:22
11:16
13:00
Daily Weather Condition
Sunny39°C
Sunny43°C
Sunny43°C
Sunny50°C
Sunny65°C
Sunny67°C
Field Data
Depth to water
16.8'
18.3
18.3
6.9
5.9
14.1
Total well depth
30'
43'
43'
20'
16'
74'
Volume of water purged before
sampling (gal)
6.5
12.25
12.25
6.5
5
30
Turbidity(NTU)
0.72
3.52
3.52
1.52
2.83
0.72
pH
5.3
5.62
5.62
5.75
6.48
5.85
Temperature
15.8
16.5
16.5
15.5
14.2
19.8
Conductivity (umhos/cm)
38.35
84.53
83.03
79.36
85.17
123.9
Iron )pg/L)
108
97
132
199
601
<50
Manganese(pg/L)
<10
71
71
16
176
71
Arsenic(pg/L)
<5
<5
<5
<5
<5
<5
*Trace Metal Analysis by Environment 1

2
Ground Water Monitoring
Plan (2019)

F�2
Ground Water
Monitoring Plan
Wrenn Road Facility Wastewater Irrigation
System
Garner, NC
February 26, 2019

hdrinc.com
February 26, 2019
Mr. Rick Bolich
NC Department of Environmental Quality
Division of Water Resources
Water Quality Regional Operations Section
Raleigh Regional Office
3800 Barrett Drive
Raleigh, NC 27609
Re: Ground Water Monitoring Plan
Permit No. WQ0002708
City of Raleigh Wrenn Road Facility Wastewater Irrigation System
Wake County, North Carolina
Dear Mr. Bolich,
On behalf of the City of Raleigh Public Utilities Department, we are resubmitting the Ground Water
Monitoring Plan requested in the approval for Permit Number WQ0002708 to support background
concentrations of manganese, iron and arsenic above the 15A NCAC 02L standards. The sampling
plan has been prepared with consideration to the guidance material suggested in the Permit
Approval letter: Aquifer Protection Section Policy for metals Determinations Required by Title 15A,
NCAC, Subchapter 2L (May, 2013) and Evaluating Metal in Groundwater at DWQ Permitted
Facilities: A Technical Assistance Document for DWQ Staff (NC DENR, July, 2012). Also, the
following US EPA groundwater monitoring guidance document was utilized: Statistical Analysis of
Groundwater Monitoring Data at RCRA Facilities -Unified Guidance: EPA 530/R-09-007.
Additionally, recommendations offered by DEQ during discussions with the City and HDR were
incorporated into the sampling plan.
In summary, the revised sampling plan will:
1. Install and develop four (4) background monitoring wells at the Wrenn Road Facility;
2. These wells will be sampled for iron, manganese, and arsenic bi-monthly for the first six (6)
months to develop background statistics for compliance monitoring;
3. Determine if 2010 sampling data is from the same population and for use in defining
background statistics for ground water monitoring;
4. Sample the new background wells for one (1) year on the same schedule used for
compliance monitoring to evaluate any time trends to consider in compliance assessments;
5. The new ground water monitoring wells will be maintained such that resampling can be
accomplished in the future if necessary.
555 Fayetteville Street Suites 900 & 210, Raleigh, NC 27601-3034
[phone]

hdrinc.com
This package contains the following:
Attachment A — The ground water monitoring plan submitted to DEQ on February 28, 2017
Attachment B — Responses to comments provided to DEQ on October 7, 2017
Attachment C — The resubmittal to DEQ by the City/HDR on December 14, 2018, providing
revised background monitoring well locations
Attachment D — Meeting minutes from a meeting held with the City, HDR, Eagle Resources,
and DEQ on January 31, 2019
Attachment E — Water well locations for the subdivision located adjacent to the Wrenn
Road Facility
Attachment F — Ground water well levels
Attachment G — A contour map of the proposed monitoring well locations
The groundwater permit WQ0002708 expires June 30, 2020. The 1-540 project will impact the
Wrenn Road Facility and the compliance boundary. The exact timing of the 1-540 project is
unknown at this time. The City will keep DEQ informed as to the progress of this project.
We have submitted a full package in order to hopefully help the review process. Should you have
any questions, please do not hesitate to call me at 919-232-6657. We look forward to hearing from
the NC Department of Environmental Quality.
Sincerely,
HDR Engineering Inc. of the Carolinas
Chris Brown, PE
Project Manager
Enclosures
CC: Chris Phelps, City of Raleigh
Dennis Lassiter, City of Raleigh
Whit Wheeler, City of Raleigh
Eric Lappala, Eagle Resources
Samantha Black, HDR
Manish Bhandari, HDR
555 Fayetteville Street Suites 900 & 210, Raleigh, NC 27601-3034
[phone]

A
Ground Water Monitoring
Plan — Submitted February
28, 2017

E�Z
hdrinc.com
February 28, 2017
Mr. Troy Doby
Non -Discharge Permitting Unit
Water Quality Permitting Section
Division of Water Resources
512 N. Salisbury Street
Raleigh, NC 27604
Re: Ground Water Monitoring Plan
Permit No. WQ0002708
City of Raleigh Wrenn Road Facility Wastewater Irrigation System
Wake County, North Carolina
Dear Mr. Doby,
On behalf of the City of Raleigh Public Utilities Department, we are providing the Ground Water
Monitoring Plan requested in the approval for Permit Number WQ0002708 to support background
concentrations of Manganese, Iron and Arsenic above the 15A NCAC 02L standards. The
sampling plan has been prepared with consideration to the guidance material suggested in the
Permit Approval letter: Aquifer Protection Section Policy for metals Determinations Required by
Title 15A, NCAC, Subchapter 2L (May, 2013) and Evaluating Metal in Groundwater at DWQ
Permitted Facilities: A Technical Assistance Document for DWQ Staff (NC DENR, July, 2012).
Also, the following US EPA groundwater monitoring guidance document was utilized: Statistical
Analysis of Groundwater Monitoring Data at RCRA Facilities -Unified Guidance: EPA 530/R-09-007.
Based on these sources and other groundwater modeling tools a ground water monitoring plan has
been developed. This detailed groundwater monitoring pian is attached, "Proposed Monitoring Plan
to Establish Background Concentration of Iron and Manganese at the Wrenn Road Spray Fields,
Wake County NC" (Plan) by Eric Lappala, P.E., P.H., Eagle Resources.
In summary the sampling plan will:
1. Install and develop five (5) new monitoring wells at the Wrenn Road Facility;
2. These wells will be sampled for Iron, Manganese and Arsenic, bi-monthly for the first six (6)
months to develop the background statistics for compliance monitoring;
3. Determine if 2010 sampling data is from the same population and for use in defining
background statistics for ground water monitoring;
4. Sample the new background wells for one (1) year on the same schedule used for
compliance monitoring, to evaluate any time trends to consider in compliance assessments.
5. The new ground water monitoring wells shall be maintained such that resampling can be
accomplished if necessary.
3733 National Drive Suite 207, Raleigh NC 27612
T 919.232.6600 F 919.785.1187

Should you have any questions, please do not hesitate to call me at [phone].
Sincerely,
HDR Engineering Inc. of the Carolinas
Randy Plummer, PE
Project Manager
RTP
Enclosures
cc: Chris Phelps
Dennis Lassiter
3733 National Drive Suite 207, Raleigh NC 27612
T 919.232.6600 F 919.785.1187

Proposed Monitoring Plan to Establish Background
Concentration of Iron and Manganese at the
Wrenn Road Sprayfields, Wake County, NC
North Carolina Non -Discharge Permit WQ0002708
Prepared for
City of Raleigh Pubic Utilities Department and
HDR Engineering of the Carolinas
April 1, 2016
(Revised February 1, 2017)
Eric G. Lappala, P.E., P.H.
11115 tag& PeAarce5
Eagle Resources, P.A.
P.O. Box 11189
Southport, NC
www.eagleresources.com
1

Contents
Introduction 1
Purpose 1
Model Analyses to select sites for background monitoring 2
Sampling Design 8
1. Identical and Independent Distributions of background and forward samples 8
2. Temporal Stationarity of Samples 10
3. Spatial Stationarity of Samples 10
4. Statistical Outliers 12
5. Use of Parametric Methods 12
6. Minimum Number of Background Samples 12
a) Additional Background Wells 13
b) Sampling to Establish Background 14
c) Initial Sampling Methodology Assessment 14
Recommended Background Determination Methodology 15
Conclusions 16
Figures
Figure 1.-- Measured and modeled water level elevations in B-3, B-8, and B-9 3
Figure 2.-- Modeled concentrations of the modeled constituent in model layer 1 as of 12/31/15. 5
Figure 3.-- Modeled concentrations of the modeled constituent in model layer 2 as of 12/31/15. 6
Figure 4.-- Modeled concentrations of the modeled constituent in model layer 3 as of 12/31/15. 7
Figure 5.-- Probability Plots for (Fe / 2L standard) and (Mn / 2L standard) for the 2010 study samples..
9
Figure 6.-- Probability plots of log -transformed values of (Fe 2L Standard) and (Mn / 2L Standard) for
the 2010 study samples. 10
Figure 7.-- Log -transformed multiple of Fe (left panel) and Mn (right panel) multiples of the 2L
Standards for samples from the 2010 study. 11
Figure 8.-- Dissolved Fe and Mn plotted against each other showing little correlation between them.... 12
Tables
Table 1.—Dissolved Fe and Mn from the 2010 study, their multiples of the 2L standards and the log
transform of the multiples of the 2L standards. 9
Table 2.-- Coordinates of Proposed Background Monitoring Wells. 13
Table 3.-- Results of purging of compliance wells on February 5, 2016 and laboratory analyses for
dissolved Fe and Mn in samples taken at the end of purging 15
i

Introduction
NC DEQ has granted Permit WQ0002708 to the City of Raleigh (City) for the continued operation and
irrigation at the Wrenn Road Facility in southeastern Wake County. This permit is a renewal for the
permit of the same number that was in effect originally to permit the same facilities for the disposal of
wastewater effluent from the treatment facilities. The Wrenn road Facility stopped receiving domestic
wastewater in 2008. The spray irrigation facilities were modified to allow treatment of residuals from
the DE Benton Water Treatment Plant (DEBWTP). WQ0002708 was amended in 2012 for the spray
irrigation modifications and to change the influent waste source to residuals from the DEBWTP. The
spray irrigation permit was renewed in 2015. The sprayfields have been used since 1989 to dispose of
treated wastewater from the Garner wastewater treatment plant (Garner WWTP). The Town of Garner
operated the WR Sprayfields until the merger of the Garner water and sewer utility systems with the
City of Raleigh in July 2000. The City of Raleigh Public Utilities Department (CORPUD) has operated
the Garner wastewater plant and the WR Sprayfields since that date.
A comprehensive Hydrogeologic and Geochemical evaluation of the site was completed by Soil and
Environmental Consultants (S&EC) and Eagle Resources for the site in 2010 and approved by DEQ as
part of the application for the currently issued permit,2,. These studies comprised the installation of
over 20 temporary piezometers, three monitoring wells, and groundwater flow, groundwater transport,
and geochemical modeling to assess both conditions prior to the application of residuals from the WTP
and to recommend loading rates to the sprayfields to assure that the likely depth to the watertable would
be compliant with the conditions of the permit.
Purpose
The permit was issued by DEQ with the condition that the City prepare a monitoring plan to assess the
background concentrations of arsenic, iron and/or manganese above the 15A NCAC .02L groundwater
standards (2L Standards). The 2010 reports documented concentrations of these constituents in samples
collected from piezometers and monitoring wells that exceeded the 2L Standards. The permit condition
also requested that CORPUD consider DWQ Staff guidance documents3,4 in preparing the plan.
These guidance documents include the statistical evaluation of data used to establish background
concentrations to account for spatial variations across complex sites. Because the piezometers from the
2010 studies have been abandoned, they and are no longer available to use for re -development and
sampling to provide this data. The three monitoring wells that have been used for compliance reporting
since the original permit was issued for the site (MW-B3, MW-B8, and MW-B-9) also are not adequate
in number or location to use for the establishment of background concentrations. These wells are not
located in areas where the 2010 study showed concentrations of the regulated metals to be above the 2L
Standards. Additionally, only three rounds of samples have been taken that have included analyses for
the metals of concern since the permit was issued and application of residuals was started in 2014.
The objective of this report is to present a plan for using data and analyses from the 2010 study
documents combined with data from additional monitoring locations to respond to the permit condition
to assess the background concentrations of iron and manganese at the facility.
1 Soil and Environmental Consultants, 2009, Site Analysis for Wrenn Road Wastewater Treatment Plant Spray Irrigation
system, Garner., Wale County, North Carolina
2 Eagle Resources, P.A., May 10, 2010, Groundwater Mounding Analysis and Groundwater Quality Assessment Wrenn Road
Wastewater Treatment Plan Spray Irrigation System Garner, Wake County, North Carolina
3 NC Division of Water Quality, July 2012: Evaluating Metals in Groundwater at DWQ Permitted Facilities: a Technical
Assistance Document for DWQ Staff.
4 NC Division of Water Quality, May 13, 2013: Aquifer Protection Section Policy for Metals Determinations Required by Title
15A North Carolina Administrative Code, Subchapter 2L.
1

Based upon the DEQ guidance documents, determination of the quality and quantity of background data
needed should consider the following:
1. Physical complexity of the site
a. Does site geology vary horizontally across the site
b. Are off -site wastes likely to migrate to and contaminate background or compliance
boundary wells
c. Have Hydrogeologic anomalies been identified?
d. Have wastes been disposed across particularly large or undocumented areas
e. Spatial extent and complexity of the waste disposal practices
2. Are background concentrations expected to be similar to 2L standards and/or similar to on -site
concentrations at the compliance boundary
3. Will site be used as a precedent for similar sites in the state
4. Will statistical proof be required to justify a non-compliance determination
At a minimum, collected data should measure maximum concentrations of permitted waste constituents
that exist at the compliance boundary and at ambient background locations, along with any spatial or
temporal trends. Moreover, sample numbers and locations should align with statistical data needs....
Therefore, background data should be collected from a hydraulically up gradient location (outside the
influence of site wastes) in immediate proximity to the site and within the same groundwater horizon
(depth/zone) as samples collected from compliance boundary wells....."
Model Analyses to select sites for background monitoring
The 2010 studies and analyses provide the documentation of the items listed above that define the
physical complexity of the site. The calibrated groundwater flow and transport model constructed for
those studies was based on site -specific data from borings, piezometers (19) monitoring wells (3), water
levels, tests for hydraulic conductivity, chemical and geochemical analyses of water samples. The
model was constructed using three layers: The Saprolite at the site was modeled as two layers each 17.7
feet thick which are referred to as the Upper Saprolite and Lower Saprolite respectively. The third layer
comprised Partially Weathered Rock (PWR) and was 15 feet thick.
Transient analyses using the model have been used to help identify those areas that are not likely to
have been impacted by migration of constituents in water applied to the Wrenn Road fields during 2014
and 2015. The initial water levels used for the transient analyses with the model were the steady state
values from the calibrated 2010 model which used a natural recharge rate of using a recharge rate of 15
inches per year. Monthly recharge for 2014 and 2015 used for model input was determined as follows:
Recharge on non-sprayfield areas = Precipitation — Evapotranspiration (ET); and (1)
Recharge on spray areas = Precipitation + Applied Effluent — ET. (2)
Precipitation for each month was taken from the grid centered on the site out of the 4km x 4km gridded
values from the National Precipitation Dataset from the PRISM website5. The PRISM datasets are
5 http://www.prism.oregonstate.edu/
2

computed using measurements from a wide range of monitoring networks that cover the conterminous
United States to which sophisticated quality control measures and a variety of modeling techniques are
applied and are available as daily, monthly and yearly time scales for the period from 1895 to the
present.
ET was taken from the global monthly ET 0.05 degree grid corresponding to the site from the MODIS
projects. This project is part of NASA/EOS project to estimate global terrestrial evapotranspiration from
earth land surface by using satellite remote sensing data. The MOD16 ET datasets are estimated using
Mu et al.'s improved ET algorithm (2011) over previous Mu et al.'s paper (2007a). The ET algorithm is
based on the Penman -Monteith equation (Monteith, 1965). Surface resistance is an effective resistance
to evaporation from land surface and transpiration from the plant canopy.
Applied effluent to each field for each month was computed using the volume applied as reported on the
Discharge Monitoring Reports (DMRs) provided by CORPUD and tables provided by HDR of the
percentage of spray heads applying to each soil type within each field that are included as Attachment 1
to this report. Attachment 2 provides a summary tabulation of the monthly effluent applied to each soil
type within each field. The unit rate applied effluent in equation (2) was determined by dividing the
volume applied by the area occupied by each soil within each field.
Modeled water level elevations in B-3, B-8, and B-9 for the period 2014 through 2015 are shown on
Figure 1 along with measured water level elevations for 2007 through 2015 Although water levels
fluctuate, they tend to fluctuate in unison over the site and model analyses show that the pattern of
groundwater flow that are determined by recharge and discharge areas does not change significantly.
361.75
331.5
v
v
LL
co 301.25
co
z
c 271
ro
w 240.75
u
210.5
180.25
150
6/1/06 5/22/075/11/08 5/1/09 4/22/104/12/11 4/1/12 3/22/133/13/14 3/3/15
t B-3
t B-8
—~ B-9
— B-3 Modeled Sy = 0.25
— B-8 Modeled Sy = 0.25
— B-9 Modeled Sy = .25
Figure 1.-- Measured and modeled water level elevations in B-3, B-8, and B-9
6 http://www.ntsg.umt.edu/project/mod16
3

Transient transport analyses for 2014 through 2015 were conducted to assess potential migration of
COCs in effluent from DEB WTP and to locate areas where it is not likely to have impacted
groundwater and hence where background monitoring sites should be located. The source term used for
these analyses was an arbitrary constituent at a concentration of 10 arbitrary units applied to the areas
that received effluent during 2014 and 2015. Figures 2 through 4 show the modeled concentrations of
the arbitrary constituent as of December 31, 2015 for each of the modeled layers.
4

13 M,=
%MW-3 4
1500 2000 Ft
f
101
63
1043
EXPLANATION
Layer 1 [C] Monitoring Wells
EM 0 Compliance Well
- 1
2 * Monitoring Well
3 * Proposed Background Well
0 2010 Mn X 2L Std (Purple)
2010 Fe X 2L Std (Orange)
Areas Irrigated in 2014 and 2015
CORPUD_Property_Boundary
Base: USGS 2010
NI to Pecs
Eagle Resources, P.A.
P.O. Box 11189
Southport, NC 28461
919-345-1013
[e-mail]
City of
Raleigh
Public
Utilties
Department
Project No.
24041.1
Approved: EGL
Date: 02/21 /16
Design data and recommendations included herein are provided as a
matter of information and should not be used for final design. Rely only on
hard copy bearing consultants original seal and signature
Modeled concentrations in Upper Saprolite of an
arbitrary solute on 12/31/2015 applied in irrigation
water at concentration of 10 arbitrary units for 2014
and 2015.
DRAFT
FIGURE
2
4

0 '36%5
EXPLANATION
Layer 1 [C] Monitoring Wells
EM 0
Mi 1
In 2
3
4
5
6
7
8
9
10
Compliance Well
* Monitoring Well
• Proposed Background Well
O 2010 Mn X 2L Std (Purple)
• 2010 Fe X 2L Std (Orange)
Areas Irrigated in 2014 and 2015
n CORPUD_Property_Boundary
Base: USGS 2010
ei to Pecs
Eagle Resources, P.A.
P.O. Box 11189
Southport, NC 28461
919-345-1013
[e-mail]
City of
Raleigh
Public
Utilties
Department
Project No.
24042.1
Approved: EGL
Date: 02/21/16
Design data and recommendations included herein are provided as a
matter of information and should not be used for final design. Rely only on
hard copy bearing consultants original seal and signature
Modeled concentrations in Lower Saprolite of an
arbitrary solute on 12/31/2015 applied in irrigation
water at concentration of 10 arbitrary units for 2014
and 2015.
DRAFT
FIGURE
3
5

MWgBr3
'4
EXPLANATION
PWR [C] Monitoring Wells
IM 0
1
2
3
4
5
f 6
7
8
9
10
1500 2000 Ft
Itr Compliance Well
* Monitoring Well
• Proposed Background Well
o 2010 Mn X 2L Std (Purple)
O 2010 Fe X 2L Std (Orange)
%° Areas Irrigated in 2014 and 2015
n CORPUD_Property_Boundary
Base: USGS 2010
i eagle Peoarce,
Eagle Resources, P.A.
P.O. Box 11189
Southport, NC 28461
919-345-1013
[e-mail]
City of
Raleigh
Public
Utilties
Department
Project No.
24041.1
Approved: EGL
Date: 02/21/16
Design data and recommendations included herein are provided as a
matter of information and should not be used for final design. Rely only on
hard copy bearing consultants original seal and signature
Modeled concentrations in Lower Saprolite of an
arbitrary solute on 12/31/2015 applied in irrigation
water at concentration of 10 arbitrary units for 2014
and 2015.
DRAFT
FIGURE
4
6

Sampling Design
DEQ has determined that the data from the 2010 report should not be used to establish background
values because the wells were not permanent and because their sampling may not have met the currently
recommended sampling methodology for metals. However, because the sample size is relatively large
(n = 21) from that study and to provide a guide to the approximate variability in concentrations of iron
and manganese over the site as an aid to establishing a background monitoring program to meet these
requirements, we have included that data its summary statistics in Table 1 as well as their as multiples
of the 2L standards. Their multiples of the 2L Standards are also shown on Figures 2 through 4 to
illustrate their spatial variability.
The USEPA guidance document7 on groundwater monitoring for compliance purposes which is
referenced in the DEQ guidance document provides the following six requirements for establishing
prediction limits for comparing background and future compliance samples:
1. Background and future sample measurements need to be identically and independently distributed;
2. Sample data do not exhibit temporal non-stationarity in the form of trends, autocorrelation, or other
seasonal or cyclic variation;
3. For inter -well tests (e.g., up-gradient-to-downgradient comparisons), sample data do not exhibit non -
stationary distributions in the form of significant natural spatial variability;
4. Background data do not include statistical outliers;
5. For parametric prediction limits, background data are normal or can be normalized using a
transformation; and
6. A minimum of 8 background measurements is available; more for non -parametric limits or when
accounting for multiple, simultaneous prediction limit tests.
1. Identical and Independent Distributions of background and forward samples
To assess the likely distributions of these data, probability plots for the multiples of the 2L standards are
shown in Figure 5. Examination of these plots and the value of the skew coefficients in Table 1 show
that the raw data is not normally distributed. However, the the log transform of the multiples of the 2L
standards closely approximate normal distributions as shown by the fit to the straight normal probability
line in Figure 6. Therefore, to meet the requirements 1 and 5 above, all background and forward
compliance samples should be log -transformed. Note that for both Mn and Fe a value of the log
transformed value of 0.0 for the multiple of the standard is equivalent to the 2L Standard (Value /
Standard = 1.0).
U.S. Environmental Protection Agency, March, 2009: Statistical Analysis of Groundwater Monitoring Data at RCRA Facilities -
Unified Guidance: EPA 530/R-09-007, chapter 18, pp 18-4.
8

v
0
u
3
2.5
2
1.5
1
0.5
0
-0.5
-1
-1.5
-2
RZ = 0.68701
•
2
1.5
•
0 50 100 150 200 250
Fe / 2L Standard
0.5
0
cn 0
N
-0.5 .'
•
-1 •
•
-1.5
••
RZ = 0.7386
•
•
-2
0 20 40 60 80 100
Mn / 2L Standard
Figure 5.-- Probability Plots for (Fe / 2L standard) and (Mn / 2L standard) for the 2010 study samples..
Study
Well No.
Fe,
mg/I
Mn,
mg/I
Fe x
Std
Log Fe
x Std
Mnx
Std
Log Mn
x Std
M W-1
11.74
1.06
39.13
1.593
21.2
1.326
M W-2
6.37
0.63
21.23
1.327
12.6
1.100
M W-3
12.33
0.04
41.1
1.614
0.8
-0.097
PZ-1
3.83
4.43
12.77
1.106
88.6
1.947
PZ-2
11.69
4.11
38.97
1.591
82.2
1.915
PZ-3
3.02
0.56
10.07
1.003
11.2
1.049
PZ-4
26.28
2.16
87.6
1.943
43.2
1.635
PZ-5
30.2
3.16
100.67
2.003
63.2
1.801
PZ-6
69.14
3.46
230.47
2.363
69.2
1.840
PZ-7
23.6
0.43
78.67
1.896
8.6
0.934
PZ-8
31.94
0
106.47
2.027
0
n/a
PZ-9
6.92
0.84
23.07
1.363
16.8
1.225
PZ-10
6.96
0.55
23.2
1.365
11
1.041
PZ-11
1.41
0.02
4.7
0.672
0.4
-0.398
PZ-12
10.3
0.25
34.33
1.536
5
0.699
PZ-14
1.52
0.33
5.07
0.705
6.6
0.820
PZ-15
0.68
0.22
2.27
0.356
4.4
0.643
PZ-16
2.39
0.26
7.97
0.901
5.2
0.716
PZ-17
2.29
0.09
7.63
0.883
1.8
0.255
PZ-18
6.16
0.08
20.53
1.312
1.6
0.204
PZ-19
3.14
0.57
10.47
1.020
11.4
1.057
Mean
12.95
1.11
43.16
1.361
22.14
0.986
Median
6.92
0.55
23.07
1.363
11.00
1.045
Variance
260
2
2887
0.268
821
0.439
Std Dev
16.12
1.43
53.73
0.517
28.65
0.662
Skew
2.40
1.45
2.40
0.012
1.45
-0.340
Table 1.-Dissolved Fe and Mn from the 2010 study, their multiples of the 2L standards and the log transform of the multiples of the 2L
standards.
9

2
1.5
1
N
N
R2 = 0.98704
1.5
1
' • 0.5
...4
•
0.5 ••
•
0
`• N.5
- 0.5 ...
-1
• -1.5
•'
-2 -2
-1
- 1.5
R2 = 0.97568
e..
4
••'
•
•
:•
•.
•
0.000 0.500 1.000 1.500 2.000 2.500 -0.500 0.000 0.500 1.000 1.500 2.000 2.500
Log (Fe / 2L Standard) Log(Mn / 2L Standard)
Figure 6.-- Probability plots of log -transformed values of (Fe 2L Standard) and (Mn / 2L Standard) for the 2010 study samples.
Conformance with requirement 1 for compliance samples will have to be assessed by periodically determining
their log transformed values and plotting their distribution compared to the background distribution.
2. Temporal Stationarity of Samples
Conformance with Requirements 1 and 2 above will require the periodic assessment of time trends in
both background and compliance samples to assess whether such trends are consistent with each being
similarly distributed. The evaluation of the background and compliance samples should be evaluated for
temporal trends using regression and/or analysis of variance. These analyses will not be possible until a
sufficient number of compliance (and background) samples are available.
3. Spatial Stationarity of Samples
Examination of the spatial patterns of the log transformed values from the 2010 for Fe shows that
concentrations of Fe were elevated in the northwest portion of the property and Mn concentrations were
elevated in the northern portion of the property as shown in Figure 7. These patterns are likely the
result of increased weathering and leaching of the soils and saprolite from the uplands at the north end of
the property to the lowlands at the southern part of the property. These patterns are not apparently
correlated with either the presence or absence of application fields or with the modeled concentrations of
the arbitrary constituent shown in Figures 4 through 4.
10

Figure 7.-- Log -transformed multiple of Fe (left panel) and Mn (right panel) multiples of the 2L Standards for samples from the 2010 study.
A similar spatial variability assessment should be made using new background data and compliance data
once a samples have been collected for at least one year on the current compliance schedule.
To further assess the spatial distribution of Fe and Mn, the log -transformed values of their respective
multiples of the 2L standards are plotted against each other for the 2010 study samples in Figure 8.
While there is a general trend in this relationship, the correlation coefficient between them is very low,
indicating a very weak relationship.
11

Log(Mn / 2L Standard)
3.5
3
2.5
2
1.5
1
0.5
0
-0.5
-1
0
f
R2 = 0.1431
•
•
•
•
•
•
•
•
•
•
• ••
•
•
•
•
•
•
1
2 3
Log(Fe / 2L Standard)
Figure 8.-- Dissolved Fe and Mn plotted against each other showing little correlation between them.
5
4. Statistical Outliers
The EPA guidance document lists two screening tools (Probability and Box Plots) and two formal
outlier tests (Dixon's and Rosner's) to identify statistical outliers8. The probability plots shown in
Figure 6 for the samples from the 2010 study show that there are no apparent outliers for the log -
transformed data for either Fe or Mn. Because samples from multiple time periods are not available for
the 2010 study samples, Box Plots to compare the values are not appropriate. However after a sufficient
number of additional background and compliance samples are available they may be useful in
identifying any outliers. Because there do not appear to be any statistical outliers for either the log -
transformed Fe or Mn data shown in Figure 6, it does not seem appropriate to apply either parameter.
5. Use of Parametric Methods
Using parametric methods to assess compliance with background requires that the background and
compliance data are both drawn from normal distributions or that the data can be transformed to normal
distributions. As shown in Figure 6 both Fe and Mn are log normally distributed and therefore at least
the data from the 2010 study meet this requirement.
6. Minimum Number of Background Samples
The EPA guidance document states that at least 8 samples should be available to establish background
for the use of prediction intervals for compliance assessment9. As few as three background observations
can be used to compute compliance but would result in a very large upper prediction limit for
background and would limit the statistical power of the test.
8 USEPA Unified Guidance document, Chapter 12.
9 USEPA Unified Guidance Document, p. 18-4.
12

Although DEQ has determined as previously stated that the sample analyses from the 2010 study cannot
be used by themselves to establish background, it is our professional opinion that that dataset as well as
samples from the 1990 study can and should be use in conjunction with additional samples to achieve
this objective. As demonstrated in the previous five sections the 2010 dataset is a) larger than the
minimum of 8 required; b) shows that parametric tests for compliance can be used if the data is log -
transformed; c) shows that the spatial variability in Fe and Mn is the result of natural variability and not
the result of past applications to fields; and d) apparently does not contain statistically significant
outliers. The recommended monitoring plan utilizes this information from the 2010 samples in
conjunction with additional background samples to be obtained from new permanent background
monitoring wells.
With the exception of compliance well MW-B3, none of the existing wells on site meet the necessary
criteria to establish background. MW-B 1 is the only well up -gradient of the fields. The remaining
compliance wells (MW-B-8 and MW-B9 and the three other permanent wells remaining on site (MW-1,
MW-2, and MW-3) are down gradient of the fields and therefore do not meet the DEQ criteria for
background wells going forward. However, data from the 2010 study for MW-1, MW-2, and MW-3 can
and should be use as part of the overall dataset used to establish background. The modeling analysis
shown in the previous section showed that there is the potential for Fe and Mn to have migrated in some
concentrations to these wells as the result of applications in 2014 and 2015 and therefore these and
future data from these wells should be excluded from the background analysis.
Because Fe and Mn were not required compliance parameters prior to the issuance of the current permit,
there is no data from the three compliance wells prior to 2015 for these parameters that could be used to
establish background.
a) Additional Background Wells
This plan recommends the installation and sampling of new wells at five (5) sites and sampled twice at 6
month intervals be used to establish background concentrations for iron and manganese. These sites
were selected based upon the transient model analyses discussed above the are shown on Figures 2
through 4 and were chosen to meet the criteria listed in the DEQ and EPA guidance. The coordinates of
these sites are shown in Table 2 below.
Well No
Easting
Northing
P-MW-1
2126155
691193
P-MW-2
2124156
688177
P-MW-3
2123614
686726
P-MW-4
2125044
688180
P-MW-5
2126427
689422
Table 2.-- Coordinates of Proposed Background Mon'toring Wells.
Type 1 monitoring wells should be constructed at these sites that are screened from the depth of the
seasonal high water permanent watertable to the top of PWR. Based upon the 2009 S&EC
hydrogeologic report for the site the new wells will be approximately 25 feet deep and have ten (10) feet
of well screen. The preferred well construction method should be sonic or air rotary drilling to
eliminate blinding off of the formation by drilling muds with hydraulic rotary or smearing of the
formation by hollow stem auger methods.
13

The wells are to be constructed using new threaded 2-inch diameter PVC casing and wire -wound screen
with a number 10 (0.01 inch) opening. The wells are to be completed with a graded sand pack installed
in the annulus between the well screen and borehole wall from the bottom of the boring to two feet
above the top of the screened interval. A bentonite seal at least 1 foot thick is to be placed on top of the
sand pack and a concrete seal placed above it to the land surface. The wells are to be completed with
above -ground, lockable, protective metal well casings.
The new background wells should be developed using industry standard procedures as documented in
the DEQ guidance document. Pumping, surging, and bailing should be used in an effort to develop the
sand pack used so as to minimize the potential for fine sediment to enter the wells during the sampling
events. Development should continue until the produced water is visibly clear and preferably has a
turbidity of 10 NTU or less or the turbidity levels are stable (three consecutive turbidity measurements
do not vary by more than 10%).
b) Sampling to Establish Background
The newly constructed background wells and the three compliance wells should be sampled on a bi-
monthly basis for the first six months following their installation to develop an adequate sample
population for background assessment. Thereafter, these wells should be sampled on the same schedule
used for the existing three compliance wells (March, July, and November) for one year to assess any
longer term time trends. Low flow purging and sampling of all wells should be used to conform with the
DEQ guidance document0. Low flow well purging should continue until turbidity levels are less than
10 NTU or vary no more than 10% and field measured pH and water temperature are similarly stable.
c) Initial Sampling Methodology Assessment
An initial evaluation of low -flow purging and sampling was conducted of the three existing compliance
wells (MW-B-3, MW-B-8, and MW-B9) on February 5,2016 by CORPUD staff using procedures
recommended by Eagle Resources to assess the ability to implement the procedures for obtaining valid
metal samples recommended by DEQ. Low flow well purging was conducted for approximately 30
minutes with pH, temperature and turbidity measurements made at approximately 7 minute intervals.
The wells were purged with the dedicated bladder pumps installed in each well controlled with a
GeoControl Pro system which filled the bladder for 20 seconds and discharged for 10 seconds, resulting
in a flow rate of 0.375 gallons per minute. The field measurements for this purging event are shown in
Table 3.
Water samples were taken at the end of the purging in pre -acidified sample containers supplied by the CORPUD
laboratory and the results of these analyses are shown in Table 3. It is apparent that the DEQ requirements for
low flow purging and sampling can be implemented for the compliance wells. While the turbidity in well MW-
B9 was slightly greater than 10 NTU, subsequent measurements were stable within 10% of the initial value.
10 NC Division of Water Quality, May 13, 2013: Aquifer Protection Section Policy for Metals Determinations Required by Title
15A North Carolina Administrative Code, Subchapter 2L.
14

ialie,7esarces
Elapsed Time, Min
1
8
16
23
Purge Volume Gal
0.38
3.00
6.00
8.63
MW-B-3
pH
4.81
4.55
4.57
4.59
Temp Deg C
15.20
15.6
15.8
15.80
NTU
0.20
1.30
1.35
0.95
Dissolved Fe (mg/I)
0.111
Dissolved Mn (mg/I)
< .05
Conductivity (umhos/cm)
43.4
MW-B-8
pH
4.80
4.74
4.83
4.79
Temp Deg C
14.80
15.1
15.1
15.10
NTU
2.43
2.00
1.48
1.86
Dissolved Fe (mg/I)
0.109
Dissolved Mn (mg/I)
0.148
Conductivity (umhos/cm)
189
MW-B-9
pH
5.61
5.15
5.06
4.97
Temp Deg C
14.20
13.8
13.9
13.90
NTU
14.90
13.40
13.10
13.30
Dissolved Fe (mg/I)
0.57
Dissolved Mn (mg/I)
< .05
Conductivity (umhos/cm)
64.2
Table 3.-- Results of purging of compliance wells on February 5, 2016 and laboratory analyses for dissolved Fe and Mn in samples taken
at the end of purging..
Recommended Background Determination Methodology
The following steps are recommended to implement the determination of background concentrations of
As, Fe, and Mn at the Wrenn Road Site:
1. Install and develop the five (5) new background monitoring wells as recommended herein;
2. Sample the background and compliance wells bi-monthly for six (6) months following the
installation and development of the new wells. The sampling should follow the recommended
low -flow purging, and field analysis for pH, Conductivity, Turbidity, and Temperature. Samples
taken should be analyzed in the CORPUD laboratory for As, Fe and Mn This will provide a
background sample size of 15 (5 wells x 3 samples) for each constituent. One duplicate should
be taken from one of the background wells that is randomly selected for each sampling round;
3. Prepare probability plots of the 15 sample results for each constituent using the log transform of
the raw values; and visually compare to the plots for the 2010 samples;
4. Conduct One-way Analysis of Variance (ANOVA) on the log -transformed values to assess
whether the new background results are from the same population as the 2010 samples;
5. If the ANOVA shows that the new and 2010 samples are from the same population, pool both to
15

Ea%,7esa«es
define the background statistics to use in compliance monitoring; or
6. If the ANOVA shows that the new and 2010 samples are not from the same population, use only
the new samples to define the background statistics to use in compliance monitoring; and
7. Sample the new background wells for one year on the same schedule used for the compliance
wells (March, July, and November) to evaluate any time trends in As, Fe, Mn to consider in
compliance assessments. Log transformation should be applied to all these data.
Conclusions
A recommended methodology for establishing the background statistics for the concentrations of
Arsenic (As) Iron (Fe) and Manganese (Mn) in groundwater at the Wrenn Road facility that can be used
in assessing compliance in the three compliance wells monitored at the site under the currently issued
permit WQ0002708. This methodology was prepared in response to a condition of the issuance of the
permit by NC DEQ.
Information on As, Fe, and Mn concentrations is available from the 2010 study at the site that was
collected before application of residual effluent from the Dempsey E. Benton Water Treatment Plant
began in 2014 under the permit. However, the wells used to collect these samples were temporary and
could not be re -sampled and the sample purging and collection methods used for that study were not
necessarily conformant with DEQ guidance for metals evaluation that was published in 2012 and 2013.
Consequently, additional background wells are recommended to be installed to supplement the 2010
data.
Five additional background wells are recommended at sites where modeling analyses conducted as part
of this plan showed that concentrations of mobile constituents contained in effluent applied in 2014 and
2015 were not likely to have reached.
The plan recommends sampling the new wells bi-monthly for six months to provide an adequate sample
size for assessing background concentrations of As, Fe, and Mn. To assess the additional value
provided by also considering the results from the 2010 study, statistical evaluations are recommended to
ascertain if data from the new wells is from the same population as that from the 2010 study. If so, all
the data should be pooled to provide a more robust sample size to establish the distributions and
statistics to use in compliance assessment. If these tests show that the new and 2010 data are not from
the same population only the new data should be used. This assessment concluded that to enable the use
of parametric tests for compliance that the raw As, Fe, and Mn concentrations should be log -
transformed.
To assess any time trends in background values of As, Fe, and Mn it is recommended that the
background wells be sampled for one year on the same schedule used for the compliance wells. The
background wells should be maintained in such as a condition that they can be resampled following this
period if necessary.
16

B
Responses to DEQ
Comments — Provided
October 7, 2017

11_ 54e Peoarce5
Rick Bolich, L.G.
Assistant Supervisor
N.C. Dept. of Environmental Quality
Division of Water Resources
Water Quality Regional Operations Section
Raleigh Regional Office
3800 Barrett Drive
Raleigh, NC 27609
rick. bolich@ncdenr. gov
October 7, 2017
Subject: Groundwater Monitoring Plan for City of Raleigh Wrenn Road Facility Permit WQ0002708.
Dear Rick;
This letter responds to your email dated May 2, 2017 to Chris Brown of HDR regarding the location of
proposed new monitoring wells to establish ambient concentrations of iron and manganese in
groundwater at the Wrenn Road Facility. Our response to the issues you provided in that email are
attached.
Please contact us if you need any further information on this matter. We are available to meet with you
if necessary to discuss any additional information that you may need to approve the monitoring plan.
Sincerely yours,
01/
Eric G. Lappala, P.E., P.H.
Attachment:
Response to additional information request
Eagle Resources, P.A.
215 West Moore Street Southport, NC 28461
919-345-1013 www.eagleresources.com

eaie ieerces
Comment:
The proposed background wells P-MW-1 and P-MW-5 appear to be in a topographically upgradient areas that
would be good locations for background assessment of groundwater conditions.
P-MW-2, P-MW-3. and P-MW-4 are not in locations suited to be background locations. They may be suitable
monitoring stations for site conditions affected by lagoon and spray field activities, but these locations are not
representative of background concentrations as they appear to be hydraulically downgradient of the waste
application areas. DWR recommends moving these two wells to a location that is unlikely to be impacted by
waste application.
Response:
The groundwater flow and transport modeling performed for this site demonstrate that all wells chosen to establish
background conditions, including P-MW-2, P-MW-3, and P-MW-4, are unlikely to have been impacted by the
application of water treatment residuals, even if they are within the boundaries of the facility. The objective of the
proposed monitoring plan is to establish statistically significant ambient background conditions that include any
contribution from applied wastewater effluent during that period.
The site was used previously by the Town of Garner and operated by the City of Raleigh to dispose of treated
wastewater effluent from 1989 through 2008 under permit WQ0002708 (Permit).
• Sampling and analysis for iron and manganese in groundwater was not required under that permit.
• The Eagle Resources 2010 study used to support the modification of the Permit detected elevated
concentrations of iron and manganese in temporary monitoring wells that were located within and down
gradient of fields that had been used for wastewater effluent from 1989 to 2008.
• Therefore, any concentrations of these constituents that are currently in groundwater are the result of both
their natural occurrence and any concentrations that may have been present in the wastewater effluent applied
under the permit from 1989 through 2008.
The application of water treatment residuals from the Dempsey E. Benton Water Treatment Plant under the amended
permit that was issued in 2012 began in 2014. The three-dimensional groundwater flow and transport model used in
the 2010 report was updated and used to assess the likely extent of migration of iron and manganese may have
occurred as the result of the application of water treatment residuals.
As documented in the 2010 report the migration of both iron and manganese in groundwater is influenced by the
complex geochemical interaction of these constituents with the soils, saprolite and weathered bedrock that underlie
the site. These interactions all act to attenuate the migration of iron and manganese relative to the migration of
groundwater via a variety of sorption processes. However, to provide the likely maximum extent of their migration
from the application of water treatment residuals, the updated model did not include any of these attenuation
processes.
The DEQ guidance document on establishing ambient background also requires that a statistically valid data set be
present that accounts for the spatial variability hydrogeologic conditions as well concentrations of the regulated
constituents that were present prior to the application of water treatment residuals. Because of the size and
complexity of the Wrenn Road site, it therefore is necessary to include monitoring sites that are within the boundaries
of the site and that may be apparently hydraulically down gradient of some application fields but that have not been
impacted by the application of water treatment residuals.
2

All the proposed monitoring wells locations were selected to meet above criteria. Locating additional wells only at
topographically up -gradient locations of all fields will not meet the requirement to account for this spatial variability
and account for presence of iron and manganese interior to the site that were detected in samples taken for the 2010
report that may have included a contribution from the application of wastewater effluent prior to 2008. Therefore,
we believe that it is scientifically appropriate to install monitoring wells at the proposed locations in order to establish
background conditions.
Comment:
Please use caution if you intend to use groundwater quality data from the 2010 Eagle Resources study and report
to establish background metals concentrations as some of the wells in this study had turbidity in excess of the
levels recommended in the NCDEQ July 2012 "Evaluating Metals in Groundwater at DWQ Permitted Facilities:
A Technical Assistance Document for DWQ Staff" as mentioned in previous correspondence. Please also note
filtered samples are not acceptable for use in establishing metals concentrations at permitted facilities in
accordance with the May 13, 2013 policy memo by Jay Zimmerman, "Aquifer Protection Section Policy for Metals
Determinations Required by Title 15A, North Carolina Administrative Code, Subchapter 2L ".
Response:
We intend to use only data that we deem in our professional opinion to be representative of background
conditions.
Comment:
DWR also recommends that any new compliance monitoring wells used to monitor potential impacts from waste
applications be placed at the review or compliance boundary.
Response:
We will consult with DWR on the location of any new compliance wells if they become necessary.
3

c
Ground Water Monitoring
Plan Resubmittal — Submitted
on December 14, 2018

Transmittal
Date: Friday, December 14, 2018
Project: City of Raleigh Wrenn Road Facility
To: Rick Bolich, L.G., DEQ
From: Chris Brown, PE, HDR
Subject: Groundwater Permit
We are sending you:
❑Z Attached
❑ Shop drawings
❑ Samples
❑ Change Order
❑ Under separate cover via the following items:
❑ Prints ❑ Plans
❑ Specifications ❑ Copy of letter
❑ Other:
Copies Date No. Description
1 Dec 13 2018 Letter from Eagle Resources — Relocated Wells
These are transmitted as checked below:
❑X For your approval
❑X For your use
❑X As requested
❑X For review/comment
❑ For bids due
❑ Approved as submitted
❑ Approved as noted
❑ Returned for corrections
❑ Other:
❑ Resubmit
❑ Submit
❑ Return
❑ Prints returned after loan to us
Remarks: Mr. Bolich —
HDR Engineering, Inc. of the Carolinas (HDR) is pleased to provide DEQ with the above item. This is
a follow up to comments received at our Oct 2017 meeting. The team has been working with the
adjacent land owner on acquisition of property.
We would like to meet in Jan 2019 to discuss a path forward.
Please let us know if you have any questions.
Copy to: Dennis Lassiter, Chris Phelps, Whit Signed: Chris Brown 919.677.9350
Wheeler, Jesse Walker, Tracy McLamb - [e-mail]
City of Raleigh; Eric Lappala, Eagle
Resources; Samantha Black, Manish
Bhandari - HDR
555 Fayetteville Street, Suite 900, Raleigh, NC 27601 hdrinc.com
[phone]

ra taie Peoarce,5
Rick Bolich, L.G.
Assistant Supervisor
N.C. Dept. of Environmental Quality
Division of Water Resources
Water Quality Regional Operations Section
Raleigh Regional Office
3800 Barrett Drive
Raleigh, NC 27609
[e-mail]
December 13, 2018
Subject: Groundwater Monitoring Plan for City of Raleigh Wrenn Road Facility Permit WQ0002708
Dear Rick,
This letter transmits the revised locations of the four (4) proposed background monitoring wells for the
subject facility that are shown on the attached map. Wells PMW-2 and PMW-3 will be installed on
property recently acquired by the City of Raleigh. Well PMW-3 is to be accessed for installation from
the adjacent subdivision which has provided permission for same. The location of PMW-1 has not
changed from the original monitoring plan We have moved the location of PMW-4 to the location
shown on the attached map to provide better access for drilling equipment.
We are available at your convenience to meet to discuss the monitoring plan and these locations if it is
necessary.
Sincerely yours,
Eric G. Lappala, P.E., P.H.
Attachments: Proposed monitoring well location map
Eagle Resources, P.A.
215 West Moore Street Southport, NC 28461
919-345-1013 www.eagleresources.com

EXPLANATION
0 Proposed Background Monitoring Wells
Property Boundaries (Wake County GIS)
Well No. Easting
PMW-1
PMW-4
PMW-2
2126151.11
2125522.18
2124505.08
Northing
691215.39
687848.49
691694.17
PMW-3 2121970.6 688486.31
F1 ta Pesar-ces
Eagle Resources, P.A.
215 West Moore Street
Southport, NC 28461
919-345-1013
[e-mail]
City of
Raleigh
Public
Utilties
Department
Project No.
24041.1
Approved: EGL
Date: 11/28/18
Design data and recommendations included herein are provided as a
matter of information and should not be used for final design. Rely only on
hard copy bearing consultants original seal and signature
Location of proposed background moniitoring wells
Wrenn Road Facilty.
;�tltIVY
CArjQ4i�fe.i
s ".7-
6990
•
;Gt4NE,r,
FIGURE
1

D
Minutes from Resubmittal
Discussion Meeting —
Meeting Held on January 31,
2019

Meeting Minutes
Project: City of Raleigh — Wrenn Road Facility Ground Water Monitoring Plan
Subject: Meeting with City and DEQ
Date: Thursday, January 31, 2019
Location: DEQ Offices, 3800 Barrett Drive
Attendees: Chris Phelps — City of Raleigh Samantha Black — HDR
Rick Bolich — DEQ Manish Bhandari — HDR
Brion Byers — DEQ Chris Brown — HDR
Eric Lappala — Eagle Resources
Goal of the Meeting
The goal of this meeting was to gain verbal approval of the Wrenn Road Facility Ground Water
Monitoring Plan so the City may proceed to the implementation and monitoring phase. An
additional goal was to make DEQ aware of changes that may come to the existing Wrenn Road
Facility following the future expansion of Interstate-540 (1-540).
History of the Wrenn Road Facilties Ground Water Monitoring Plan
A brief history of the Wrenn Road Facility Ground Water Monitoring Plan was provided during
the meeting as follows:
• The current permit (WQ0002708) was issued in 2015, and allowed the continued
operation of the Wrenn Road Facility. Part of this permit was the requirement that the
City monitor ground water wells for manganese, iron, and arsenic.
• In February 2017, a revised monitoring plan was submitted to DEQ.
• In May 2017, comments on the revised plan were received by DEQ.
• In October 2017, the City/HDR provided responses to DEQ comments, and a meeting
was held with the City, DEQ, and HDR to discuss these responses. Changes to some of
the background wells were requested by DEQ during this meeting.
• In 2018, the City obtained a parcel of land adjacent to the Wrenn Road Facility. This
parcel provided options for locating background wells. This parcel will provide easier
access to monitoring well #3.
• In December 2018, revised background well locations were submitted to DEQ for review.
These locations were selected based on fieldwork conducted by Eagle Resources and
the well driller. Two well locations were added to the west of the Wrenn Road Facility.

Revised Well Locations
There are four proposed monitoring wells (PMWs). PMW-4 was relocated to avoid a drilling
access issue, and it is now on the access road. DEQ is interested in the ground water flow
directions for PMW-4, and requested a 5-ft contour map of this site. Additionally, a water table
map and water levels were requested.
Wells will be drilled into partially weathered rock, and are not considered bedrock wells. It is
estimated that the depth of these wells will be less than 50 feet. The nearby subdivision ground
water well might influence PMWs if they are to be drilled into partially weathered rock. It was
suggested that a monitoring device be put in to observe the diurnal influence of the subdivision
well. The partially weathered rock is a relatively high permeability, and there is no significant
change in water level based on a recent study. The screening level of the PMWs will be from
the bottom, across the water table.
Impacts of 1-540 to the Wrenn Road Facility
In the future, 1-540 will be expanded on a portion of the Wrenn Road Facility. It is expected that
this expansion will result in the abandonment of at least one MW, consumed 15 to 16 acres of
irrigation land, and change the compliance boundary. The 1-540 design -build project is in the
early stage of design, and it is anticipated that it will be one year until the design is complete. A
conceptual drawing of where 1-540 will be located was provided in the agenda. The City will deal
with the changes caused by the 1-540 expansion project when the design is closer to
completion. The PMWs will not be impacted by 1-540.
It may be beneficial to submit the ground water monitoring plan once changes from the 1-540
project are established since construction will impact the water table. However, the City will
need to submit a permit modification after the new compliance boundary is established.
Alternatively, having a plan in place prior to 1-540 construction may be beneficial as well to get
background data collected before construction for comparison purposes.
The City plans to wait to abandon wells impacted by 1-540 until they can no longer use
associated the spray irrigation area. Although 15 to 16 acres of land will be lost due to the 1-540
expansion, the City currently has excess capacity. However, the permit will still need to be
modified to reflect the new capacity.
Action Items and Next Steps
• HDR/Eagle Resources to provide existing subdivision water well locations, ground water
well levels, well depth, and a contour map to DEQ.
• DEQ will review information and generate a ground water flow map.
• HDR to resubmit the revised Wrenn Road Facility Ground Water Monitoring Plan to DEQ
for review.
These minutes were prepared by Samantha Black with HDR> Please provide comments within
5 days of receipt to [e-mail] or 919-232-6638.

E
Water Well Locations for
Subdivision Adjacent to the
Wrenn Road Facility

Appendix E — Water Well Locations for
Subdivision Adjacent to the Wrenn Road Facility
HDR has identified three wells located within the Glen Creek Community:
1. Well 1: One drinking water well is completely developed, and is located on the north side
of the community (Figures 1 and 2).
2. Well 2: A second drinking water well has been drilled, but is not currently in use, and is
located the south side of the community (Figures 3 and 4).
3. Well 3: The third well is an irrigation well, which supplies irrigation water to the
community (Figures 5 and 6).
Table 1 provides a summary of these community wells, and the following figures show
photographs of wells and their locations relative to the closest proposed monitoring wells
(PMWs).
Table 1. Glen Creek Community Wells
Well
Use
Latitude, Longitude
Closest PMW
1
Drinking Water
35.6466, -78.5855
PMW-2
2
Drinking Water
35.6363, -78.5937
PMW-3
3
Irrigation Water
35.6503, -78.5803
PMW-2
Figure 1. Existing Drinking Water Well Located on the North Side of the Glen Creek Community
1

Well No. Easting
2126151.11
2125522.18
2124505.08
PMW-3 2121970.6
Northing
691215.39
687848.49
691694.17
688486.31
Approximate
location of
existing
drinking
water well
Figure 2. Existing Drinking Water Well Location Relative to PMW-2
`LW POOLE WELL & PUMP CO. _
'O BOX 1958 WENDELL, N.C. 27591
919-266-9223
CERTIFICATION #J
DATE COMPLETED: Fi
_ DEPTH:-
CASING DEPTH:_ _FL DIAMEiER:`1N.
STATIC WATeq LEVEL_ _
Y1ELp;
GPM
i 0sP Via. _r i
Figure 3. Future Drinking Water Well Located on the South Side of the Glen Creek Community
Approximate
location of
future drinking
water well
Figure 4. Future Drinking Water Well Location Relative to PMW-3
2

Figure 5. Existing Irrigation Well Located on the North Side of the Glen Creek Community
Approximate
location of
irrigation well
Figure 6. Irrigation Well Location Relative to PMW-2
3

F
Ground Water Well Levels

City of Raleigh Ground Water Monitoring Plan
Wrenn Road Facility
Ground Water Well Levels
B-3
MP Elev
346.00
B-8
MP Elev
226.46
B-9
MP Elev
247.94
Date
DTW
WL EL
Date
DTW
WL EL
Date
DTW
WL EL
3/9/2017
19.70
326.30
42803.00
20.50
205.96
42803.00
11.20
236.74
7/5/2017
20.60
325.40
42921.00
21.10
205.36
42929.00
12.10
235.84
11/7/2017
22.80
323.20
43046.00
23.60
202.86
42937.00
12.30
235.64
3/8/2018
22.00
324.00
43167.00
22.30
204.16
43046.00
12.20
235.74
7/5/2018
22.40
323.60
43286.00
23.00
203.46
43167.00
11.40
236.54
7/12/2018
22.60
323.40
43293.00
23.20
203.26
43286.00
12.60
235.34
11/8/2018
21.50
324.50
43412.00
22.70
203.76
43293.00
12.50
235.44

G
Contour Map of Proposed
Monitoring Well Locations

500
EXPLANATION
0 Compliance Wells and July 2018 Water Level
Q Background Wells
Property Boundaries (Wake County GIS)
Land Surface Elevation
Modeled Steady State Watertable 2014
Well No.
Water Table Elev
MW-B-9
235.34
MW-B-8
203.26
MW-B-3
323.4
0
MW-B-9
'4235.34
500
1000
1500
2000 Ft
MW-B-3
323.4
0
PMW-4,
PMW-1
PP� taie Pesarces
Eagle Resources, P.A.
215 West Moore Street
Southport, NC 28461
919-345-1013
[e-mail]
City of
Raleigh
Public
Utilties
Department
Project No.
24041.1
Approved: EGL
Date: 02/02/19
Design data and recommendations included herein are provided as a
matter of information and should not be used for final design. Rely only on
hard copy bearing consultants original seal and signature
Proposed background moniitoring wells, existing
compliance wells, topography, modeled steady state
watertable elevations, and measured water level
elevations in July 2018, Wrenn Road Facilty
FIGURE
1

This page intentionally left blank

HDR Engineering, Inc. of the Carolinas
555 Fayetteville Street
Suite 900
Raleigh, North Carolina, 27601
919-232-6600
NCBELS Number F-0116
hdrinc.com
© 2019 HDR, Inc., all rights reserved

3
Wrenn Road Background
Monitoring Well Installation
Report (2019)

E�Z
hdrinc.com
November 19, 2019
Mr. Rick Bolich
NC Department of Environmental Quality
Division of Water Resources
Water Quality Regional Operations Section
Raleigh Regional Office
3800 Barrett Drive
Raleigh, NC 27609
Re: Ground Water Monitoring Plan
Permit No. WQ0002708
City of Raleigh Wrenn Road Facility Wastewater Irrigation System
Wake County, North Carolina
Dear Mr. Bolich,
On behalf of the Public Utilities Department I Raleigh Water, we are submitting the attached
Installation and Testing of Background Wells report prepared by Eagle Resources, P.A., under
subcontract to HDR. This report was prepared to satisfy requirements of the Ground Water
Monitoring Plan for the Wrenn Road Facility Wastewater Irrigation System Package, submitted to
NC DEQ DWR in February 2019, and approved in April 2019.
Should you have any questions, please do not hesitate to call us at 919-232-6657.
Sincerely,
HDR Engineering Inc. of the Carolinas
Chris Brown, PE
Project Manager
Enclosures
CC: Chris Phelps, Public Utilities Department I Raleigh Water
Dennis Lassiter, Public Utilities Department I Raleigh Water
Whit Wheeler, Public Utilities Department I Raleigh Water
Eric Lappala, Eagle Resources
Samantha Black, HDR
Manish Bhandari, HDR
555 Fayetteville Street Suites 900 & 210, Raleigh, NC 27601-3034
[phone]

Ira taqiePeoarce,5
Chris Brown, P.E.
HDR
555 Fayetteville Street
Suite 900
Raleigh, NC
27601
11/08/19
Subject: Wrenn Road Background Monitoring Well Installation Report
Dear Chris;
This letter transmits the updated data and information from my observations of the installation and
testing of the four background monitoring wells at the Wrenn Road facility. These wells were installed
as part of the monitoring program to establish background concentrations of Fe, Mn, and As in
groundwater in accordance with the monitoring plan documented in our report dated February 2017 and
approved by the NC Division of Water Resources, Raleigh Regional Office (NCDWR RRO). This
update includes the results of turbidity testing on PMW-3 and PMW-4 that was conducted on 11/06/19
at your request.
Sincerely yours,
Eric G. Lappala, P.E., P.H.
Attachment: Well Installation Report?
Eagle Resources, P.A.
215 West Moore Street, Southport, NC 28461
919-345-1013 www.eagleresources.com

Installation and Testing of Background Wells
City of Raleigh Wrenn Road Facility, Garner, NC
Prepared for:
HDR
and
City of Raleigh
Public Utilities Department
September 25, 2019
(Updated 11/08/19)
t4kAl 4-4 x
I•
�rl
Eric G, Lappala, P.E., P.H.
esai, kien5urce -;
EAGLE RESOURCES, P.A.
215 WEST MOORE STREET
SOUTHPORT, NC 28461

Table of Contents
Introduction 1
Well Installation 1
Turbidity Testing 2
Pump Testing 4
Sampling Protocol Recommendations 5
Attachment 1 Photos and Description of Drill Cutting Samples 7
PMW-1 7
Attachment 2 Well Completion Records 11
Attachment 3 Pumping Test Analysis Curves 15
Figures
Figure 1.-- Locations of Installed Background Monitoring Wells. 6
Tables
Table 1.-- Well Completion Information 1
Table 2.-- Turbidity measurements in PMW-1. 2
Table 3.-- Turbidity measurements in PMW-2. 2
Table 4.-- Turbidity measurements in PMW-4. 3
Table 5.--Pumping and recovery test analysis results. 5
i

eaiSPegu-ces
Introduction
This report documents the installation, turbidity testing, water level measurements, and estimated aquifer
hydraulic parameters for four wells installed at the Wrenn Road facility. These wells were installed to be
used as part of the program' that has been approved by NC DWR to establish background concentrations
of iron (Fe), Manganese (Mn), and Arsenic (As) to use as alternatives to the NC 2L groundwater standards
for these constituents. The locations of these wells are shown on Figure 1 and were determined by GPS
by Eagle Resources.
Well Installation
The wells were all installed by Geologic Exploration of Statesville, NC under the direction and contract
to HDR. The installation dates and completion information provided by driller are shown in Table 1. At
the direction of Eagle Resources, all wells were drilled and completed with depths that extended at least
into the Partially Weathered Rock (PWR) that underlies the soil and saprolite at all locations. All wells
were drilled with a GeoprobeTM track -mounted drill rig that had the capabilities for both down -hole air -
percussion (Air) and hollow -stem auger (HSA) methods.
Units
Well ID
PMW-1
PMW-2
PMW-3
PMW-4
Date Drilled
8/13/19
8/14/09
8/26/19
8/13/19
Drill Method
HSA
HSA
HSA
Air/ HSA
Drill Diameter
In
10/6
8
8
8
Depth
Ft
43
20
16
74
Screen Top Depth
Ft
33
10
6
64
Screen Bottom Depth
Ft
43
20
16
74
Sand Pack Top Depth
Ft
31
8
4
61
Sand Pack Bottom Depth
Ft
43
20
16
74
Bentonite Top Depth
Ft
29
6
3
58
Bentonite Bottom Dept
Ft
31
8
4
61
Grout Top Depth
Ft
0
0
0
0
Grout Bottom Depth
Ft
29
6
3
58
Static Water Level Depth Driller
Ft
22
5
2
22
Stickup
Ft
3.0
3.0
3.7
2.9
Depth to Water from TOC (8/26/19)
Ft
23.63
7.99
7.60
20.22
Table 1.-- Well Completion Information.
Well PMW-4 was installed to the completed depth using Air but HSA was used to complete the well as
the open hole caved at a depth of approximately 22 feet. All other wells were installed using the HSA
method. Completion of all wells was accomplished by installation of screen, casing, sand pack, bentonite,
and grout as the HSA was removed. Grout was installed by pumping with a tremie pipe to assure no
bridging.
All wells were developed by the driller by surging and pumping with a submersible pump until the pump
discharge was visibly clear.
Soil samples were collected by either the driller or Eagle Resources at 5 to 10-foot intervals or significant
1 Eagle Resources, 2017: Proposed Monitoring Plan to Establish Background Concentration of Iron and Manganese at the
Wrenn Road Sprayfields Wake County, NC.
1

eaie 1e:irce5
change in the visual appearance of drill cuttings during drilling. The sample descriptions and photos of
the sampled materials are shown in Attachment 1. The logs of materials encountered by the driller and
well construction details are included in the Well Completion Records (Forms GW-3) and are included as
Attachment 2.
Turbidity Testing
Wells PMW-1, PMW-2, and PMW-4 were tested for turbidity during pumping on August 26, 2019 by
Eagle Resources. PMW-3 was not tested because it was bit installed prior to the time turbidity testing
equipment having to be returned. However, turbidity testing in this well was completed on 11/06/19 as
discussed below. Pumping was conducted by Geologic Exploration using a downhole submersible pump.
Turbidity measurements were made on samples collected during pumping with a Hanna HI 98703 Portable
Turbidimeter. For wells PMW-1 and PMW-2, pumping continued until the turbidity readings became
stable or were less than 5 NTU. Well PMW-4 was cycled between pumping and recovery in an attempt
to produce stable and low turbidity readings. Pumping rates were determined by using a bucket of known
volume and a stopwatch.
Turbidity readings and chart for each well are shown in Tables 2, 3, and 4.
Well
Pumping Time
Turbidity
Pumping Rate
Minutes
NTU
GPM
PMW-1
5
524
0.94
9
21.4
0.94
13
5.47
0.94
20
2.79
0.94
25
1.38
0.94
30
1,05
0.94
1000
D
1-
Z 100
42
10
1
PMW-1
0 10 20 30 40
Pumping Time, Minutes
Table 2.-- Turbidity measurements in PMW-1.
Well
Pumping Time
Turbidity
Pumping Rate
Minutes
NTU
GPM
PMW-2
2
210
1.41
6
22.9
1.41
10
7.95
1.41
21
4.86
1.41
25
5.78
1.41
35
5.57
1.41
40
4.64
1.41
1000
1
PMW-2
0 10 20 30 40 50
Pumping Time, Minutes
Table 3.-- Turbidity measurements in PMW-2.
2

tag& Pea rCe5
Well
Pumping Time
Turbidity
Pumping Rate
Minutes
NTU
GPM
PMW-4
2
610
0.84
5
484
0.84
9
394
0.65
17
368
0.56
24
216
0.56
29
254
0.56
38
pump off
50
pump on
51
184
0.76
57
174
0.60
65
136
0.53
75
213
0.56
80
442
0.56
83
462
0.56
Turbidity, NTU
1000
100
10
Table 4.-- Turbidity measurements in PMW-4.
PMW-4
ti
J
0 20 40 60 80 100
Pumping Time, Minutes
On 11/06/19 PMW-3 and PMW-4 were tested for turbidity using a portable downhole submersible pump
and a portable turbidity meter. Pumping from PMW-3 was continuous at an estimated 1 gpm. Pumping
from PMW-4 was cyclic as the measured depth to water in the well was 22.55 feet below the top of casing
and only 25 feet of discharge line was available and after approximately 10 seconds of pumping the water
in the well was drawn down below the pump intake. Consequently, samples were taken after the well was
allowed to recover for approximately 15 seconds. The turbidity readings for these tests are shown in
Tables 5 and 6.
Well
Pumping Time
Turbidity
Pumping Rate
Minutes
NTU
GPM
PMW-3
(11/06/19)
1
46.6
nm
5
22.5
nm
10
8.01
nm
15
5.06
nm
20
6.54
nm
25
1.67
nm
30
3.05
nm
100
D
1-
Z
10
197
PMW-3 (11/06/19)
0 10 20 30 40
Table 5.-- Results of turbidity testing on PMW-3 on 11/06/19.
Pumping Time, Minutes
3

to /e Pe5arce5
Well
Pumping Cycle
Turbidity
Pumping Rate
No
NTU
GPM
PMW-4
(11/06/19)
2
39.3
nm
3
33
nm
4
31.3
nm
5
25.6
nm
6
18.7
nm
7
25
nm
8
18.9
nm
9
26.9
nm
10
28.7
nm
Turbidity, NTU
100
10
PMW-4 (11/06/19)
1 3 5
Table 6.-- Results of turbidity testing on PMW-4 on 11/06/19.
Pumping Cycle
9
Based upon the turbidity readings in PMW-1, PMW-2, and PMW-3 it appears that purging these wells for
at least 30 minutes of continuous pumping should achieve levels consistent with the sampling and analysis
protocol recommended in the approved monitoring program of 10 NTU or less.
The initial turbidity readings in PMW-4 did not stabilize and were not as low as potentially may be
achieved. Subsequent testing on 11/06/19 showed that pumping from the top of the water column in the
well was approximately stable at 20 NTU. Because the dedicated air-lift pump in this well is set at the
bottom of the well, it is recommended that this well be further developed by air-lift pumping and surging
and additional turbidity measurements made if this low level is not observed while purging before
sampling. .
Pump Testing
Although it was not required as part of the approved monitoring program, water level changes during
pumping and recovery cycles of PMW-1, PMW-2, and PMW-4 were recorded by manual measurements
with an electric water level sounder and with a downhole recording transducer that was read at the surface
(In -Situ LevelTrollTM 400).
These water level changes and the corresponding pumping rates were used to evaluate the transmissivity,
hydraulic conductivity, and storage properties of the formation sections in which the wells were screened.
The water level and pumping data were analyzed using AgteSOLVTM. The results are summarized in
Table 5. The analysis curves for both the Theis and Neuman analysis methods for unconfined aquifers
are presented as Attachment 3.
4

tag& Pe5arC85
Well ID
Units
PMW-1
PMW-2
PMW-3
PMW-4
formation thickness, b
ft
21
15
No test
52
Pumping rate(s), Q
oz
18
18
18
gal
0.140625
0.140625
0.140625
sec
9
6
15
min
0.15
0.1
0.25
gpm
0.94
1.41
0.56
Aquifer type
Unconfined
Unconfined
Method
Theis
Theis
Transmissivity, T
ft"2/d
32
162
1.5
Hydraulic conductivity, K
ft/d
1.5
10.8
0.029
Storage Coefficient, S
Dim
8.00E-05
0.0025
0.0056
Vertical to Horizontal K, Kz/Kr)
Dim
1
1
1
Neuman
Neuman
Neuman
Transmissivity, T
ft"2/d
7.2
131
1.07
Hydraulic conductivity, K
ft/d
0.34
8.73
0.02
Storage Coefficient, S
Dim
0.009
0.0035
0.02
Table 7.--Pumping and recovery test analysis results.
Sampling Protocol Recommendations
Sampling protocol should meet the requirements of the approved background sampling program for the
site as documented on page 14 of the approved report (footnote 1). Documentation of sampling should
use the spreadsheet developed by HDR.
5

EXPLANATION
Monitoring Wells
40 Background Monitoring Well
O Compliance Monitoring Well
Property Boundaries (Wake County GIS)
2000 Ft
Eagle Resources, P.A.
215 West Moore Street
Southport, NC 28461
919-345-1013
[e-mail]
City of
Raleigh
Public
Utilties
Department
Project No.
24041.1
Approved: EGL
Date: 09/25/19
Design data and recommendations included herein are provided as a
matter of information and should not be used for final design. Rely only on
hard copy bearing consultants original seal and signature
Location of installed background moniitoring wells
and compliance wells. Wrenn Road Facilty.
kyt cod.*
Jr 6990 111
FIGURE
1

tale Pe5arce5
Attachment 1 Photos and Description of Drill Cutting Samples
PMW-1

PMW-2
PMW-2
Depth, Ft
Description
Color
5
Brown to tan silty sand
soil and saprolite
10 YR 7/4
F
10
Dark brown sandy
saprolite minor rock
fragments, moist
10 YR 2/2
r
15
Dark brown sandy
saprolite minor rock
fragments, moist
10 YR 2/2
20
Dark Brown to green
brown sandy saprolite
minor mica
10 YR 2/2
8

tag& Pe5arC85
PMW-3
PMW-3
Depth, Ft
Description
Color
5
Dark Brown organic sandy
saprolite minor mica
5 YR 2/2
PP
10
Dark brown sandy
saprolite, large rounded
pebbles abundant mica
flakes moist to saturated
5 Y 4/4
15
Dark brown sandy
saprolite minor rock
fragments saturated
10 YR 2/2
9

PMW-4
PMW-4
Depth, Ft
Description
Color
0 -5
Reddish Brown Sandy Soil,
dry
2.5 YR 2/8
10
Orange Brown Coarse
sandy saprolite, dry
10 YR 4/6
15
Dark tan to orange brown
sandy saprolite dry
5 YR 4/4
20
Tan saprolite - sandy clay
very moist to saturated
10 YR 6/6
25
Tan saprolite - sandy clay
very moist to saturated
10 YR 6/6
30
Tan saprolite - sandy clay
very moist to saturated
10 YR 6/6
35
Clayey silt slightly sandy
saprolite - saturated
10 YR 5/4
40
Weathered to partially
weathered rock drier
5 YR 6/4
45
Weathered to partially
weathered rock very moist
10 YR 4/4
50
Weathered to partially
weathered rock saturated
10 YR 4/4
10

tale Pe5arce5
Attachment 2 Well Completion Records
11

WELL CONSTRUCTION RECORD
This form can be used for single or multiple wells
1. Well Contractor Information:
For Internal Use ONLY:
JOHNNY BURR
Well Contractor Name
A - 3098
NC Well Contractor Certification Number
GEOLOGIC EXPLORATION, INC
Company Name
2. Well Construction Permit #:
List all applicable well construction permits (i.e. County, State, Variance, etc.)
3. Well Use (check well use):
Water Supply Well:
❑ Agricultural
❑Geothermal (Heating/Cooling Supply)
❑Indu strial/Commercial
❑Irrigation
❑Municipal/Public
❑Residential Water Supply (single)
❑Residential Water Supply (shared)
Non -Water Supply Well:
OMonitoring
❑Recovery
Injection Well:
El Aquifer Recharge
❑Aquifer Storage and Recovery
El Aquifer Test
ElExperimental Technology
❑Geothermal (Closed Loop)
El Geothermal (Heating/Cooling Return)
El Groundwater Remediation
❑ Salinity Barrier
❑ Stormwater Drainage
El Subsidence Control
❑ Tracer
El Other (explain under #21 Remarks)
4. Date Well(s) Completed: 08/14/19 Well ID#
5a. Well Location:
WRENN ROAD WASTE WATER PLANT
Facility/Owner Name
PMW-1
Facility ID# (if applicable)
8828 WRENN ROAD GARNER 27529
Physical Address, City, and Zip
WAKE
County Parcel Identification No. (PIN)
5b. Latitude and Longitude in degrees/minutes/seconds or decimal degrees:
(if well field, one lat/long is sufficient)
35° 38' 20.87" N 78° 34' 59.72"
6. Is (are) the well(s): ©Permanent or ❑Temporary
W
7. Is this a repair to an existing well: ❑Yes or ❑No
If this is a repair, fill out known well construction information and explain the nature of the
repair under #21 remarks section or on the back ofthis form.
8. Number of wells constructed:
For multiple injection or non -water supply wells ONLY with the same consfruethn, you can
submit one form.
1
9. Total well depth below land surface: 43'0 (ft.)
For multiple wells list all depths rf d fferent (example- 3g200' and 2@100)
10. Static water level below top of casing: 22.0 (ft.)
If water level is above casing, use ••+"
11. Borehole diameter: 10.016.0 (in.)
12. Well construction method: AUGER/AIR
(i.e. auger, rotary, cable, direct push, etc.)
FOR WATER SUPPLY WELLS ONLY:
13a. Yield (gpm) Method of test:
13b. Disinfection type: Amount:
14. WATER ZONES
FROM
TO
DESCRIPTION
ft.
ft.
ft.
ft.
15. OUTER CASING (for multi -cased wells) OR LINER (if ap licable)
FROM
TO
DIAMETER
THICKNESS MATERIAL
ft.
ft.
in.
16. INNER CASING OR TUBING (geothermal closed -loop)
FROM
TO
DIAMETER
THICKNESS
MATERIAL
0.0 ft
33.0 IL
2.0 in.
SCH 40
PVC
ft.
ft.
in.
17. SCREEN
FROM
TO
DIAMETER
SLOT SIZE
THICKNESS
MATERIAL
33.0 ft.
43.0 ft.
2.0 m•
.010
SCH 40
PVC
ft.
ft.
in.
18. GROUT
FROM
TO
MATERIAL
EMPLACEMENT METHOD & AMOUNT
0.0 ft.
29.0 ft
PORTLAND1BJTONITE
SLURRY
ft.
ft.
ft.
ft.
19. SAND/GRAVEL PACK (if applicable)
FROM
TO
MATERIAL
EMPLACEMENT METHOD
31.0 ft.
43.0 ft
20-40
FINE SILICA SAND
ft.
ft.
20. DRILLING LOG (attach additional sheets if necessary)
FROM
TO
DESCRIPTION (color, hardness, soiVrock type, grain size, etc)
0.0 ft.
1.0 rt•
GRAVEL
1.0 ft
6.0 ft
ORANGE SANDY CLAY
6.0 ft
40.0 ft.
BROWN SILTY CLAY
40.0 ft
43.0 ft.
BROWN ROCK
ft.
ft.
ft.
ft.
ft.
ft.
21. REMARKS
BENTONITE SEAL FROM 29.0 TO 31.0 FEET
22. Certification:
Signature of Certified Well Contractor
09/05/19
D ate
By signing this form, I hereby certlfy that the well(s) was (were) constructed in accordance
with 15A NCAC 02C .0100 or 15A NCAC 02C .0200 Well Construction ,Standards and that a
copy of this record has been provided to the well owner.
23. Site diagram or additional well details:
You may use the back of this page to provide additional well site details or well
construction details. You may also attach additional pages if necessary.
SIJB141ITTAL INSTUCTIONS
24a. For All Wells: Submit this form within 30 days of completion of well
construction to the following:
Division of Water Quality, Information Processing Unit,
1617 Mail Service Center, Raleigh, NC 27699-1617
24b. For Infection Wells: In addition to sending the form to the address in 24a
above, also submit a copy of this form within 30 days of completion of well
construction to the following:
Division of Water Quality, Underground Injection Control Program,
1636 Mail Service Center, Raleigh, NC 27699-1636
24c. For Water Supply & Injection Wells: In addition to sending the form to
the address(es) above, also submit one copy of this form within 30 days of
completion of well construction to the county health department of the county
where constructed.
Form GW-1
North Carolina Department of Environment and Natural Resources -Division of Water Quality Revised Jan. 2013

WELL CONSTRUCTION RECORD
This form can be used for single or multiple wells
1. Well Contractor Information:
For Internal Use ONLY:
JOHNNY BURR
Well Contractor Name
A - 3098
NC Well Contractor Certification Number
GEOLOGIC EXPLORATION, INC
Company Name
2. Well Construction Permit #:
List all applicable well construction permits (i.e. County, State, Variance, etc.)
3. Well Use (check well use):
Water Supply Well:
❑ Agricultural
El Geothermal (Heating/Cooling Supply)
❑Industrial/Commercial
❑Irrigation
❑Municipal/Public
❑Residential Water Supply (single)
❑Residential Water Supply (shared)
Non -Water Supply Well:
❑✓Monitoring
❑Recovery
Injection Well:
❑ Aquifer Recharge
❑ Aquifer Storage and Recovery
❑Aquifer Test
❑Experimental Technology
El Geothermal (Closed Loop)
❑Geothermal (Heating/Cooling Return)
❑ Groundwater Remedi ation
❑ Salinity Barrier
❑ Stormwater Drainage
❑Subsidence Control
❑ Tracer
❑ Other (explain under #21 Remarks)
4. Date Well(s) Completed: 08/14/19 Well ID#
5a. Well Location:
WRENN ROAD WASTE WATER PLANT
PMW-2
Facility/Owner Name Facility ID# (if applicable)
8828 WRENN ROAD GARNER 27529
Physical Address, City, and Zip
WAKE
County Parcel Identification No. (PIN)
5b. Latitude and Longitude in degrees/minutes/seconds or decimal degrees:
(if well field, one tat/long is sufficient)
35° 38' 20.87" N 78° 34' 59.72"
6. Is (are) the well(s): ©Permanent or ❑Temporary
W
7. Is this a repair to an existing well: ❑Yes or ONo
If this is a repair, fill out known well construction information and explain the nature of the
repair under #21 remarks section or on the back of this form.
8. Number of wells constructed: 1
For multiple injection or non -water supply wells ONLY with the same constnw ion, you can
submit one form.
9. Total well depth below land surface: 20'0 (ft.)
For multiple wells list all depths if different (example- 3@200'and 2@100)
10. Static water level below top of casing: 5'0 (ft.)
If water level is above casing, use "+"
11. Borehole diameter: 10.0/6.0 (in.)
12. Well construction method: AUGER/AIR
(i.e. auger, rotary, cable, direct push, etc.)
FOR WATER SUPPLY WELLS ONLY:
13a. Yield (gpm) Method of test:
13b. Disinfection type: Amount:
14. WATER ZONES
FROM
TO
DESCRIPTION
ft.
ft.
ft.
ft.
15. OUTER CASING (for multi -cased wells) OR LINER (if ap licable)
FROM
TO
DIAMETER
THICKNESS MATERIAL
ft.
ft.
in.
16. INNER CASING OR TUBING (geothermal closed -loop)
FROM
TO
DIAMETER
THICKNESS
MATERIAL
0.0 ft.
10.0 it.
2.0 in.
SCH 40
PVC
ft.
ft.
in.
17. SCREEN
FROM
TO
DIAMETER
SLOT SIZE
THICKNESS
MATERIAL
10.0 ft.
20.0 ft•
2.0 m'
.010
SCH 40
PVC
ft.
ft.
in.
18. GROUT
FROM
TO
MATERIAL
EMPLACEMENT METHOD & AMOUNT
0.0 ft.
6.0 ft.
PORTL5 D1BJTONITE
SLURRY
ft.
ft.
ft.
ft.
19. SAND/GRAVEL PACK (if applicable)
FROM
TO
MATERIAL
EMPLACEMENT METHOD
8.0 ft.
20.0 It
20-40
FINE SILICA SAND
ft.
ft.
20. DRILLING LOG (attach additional sheets if necessary)
FROM
TO
DESCRIPTION (color, hardness, soillrock type, grain size, etc.)
0.0 ft.
5.0 It•
BROWN SANDY CLAY/ROCKS
5.0 ft•
9.0 ft•
BROWN PWR
9.0 ft•
20.0 ft•
BROWN ROCK
ft.
ft.
ft.
ft.
ft.
ft.
ft.
ft.
21. REMARKS
BENTONITE SEAL FROM 6.0 TO 8.0 FEET
22. Certification:
Signature of Certified Well Contractor
09/05/19
D ate
By signing this form, I hereby certify that the well(s) was (were) constructed an accordance
with 15A NCAC 02C .0100 or 15A NCAC 02C .0200 Well Construction Standards and that a
copy of this record has been provided to the well owner.
23. Site diagram or additional well details:
You may use the back of this page to provide additional well site details or well
construction details. You may also attach additional pages if necessary.
SUBMITTAL INSTUCTIONS
24a. For All Wells: Submit this form within 30 days of completion of well
construction to the following:
Division of Water Quality, Information Processing Unit,
1617 Mail Service Center, Raleigh, NC 27699-1617
24b. For Infection Wells: In addition to sending the form to the address in 24a
above, also submit a copy of this form within 30 days of completion of well
construction to the following:
Division of Water Quality, Underground Injection Control Program,
1636 Mail Service Center, Raleigh, NC 27699-1636
24c. For Water Supply & Infection Wells: In addition to sending the form to
the address(es) above, also submit one copy of this form within 30 days of
completion of well construction to the county health department of the county
where constructed.
Form GW-1
North Carolina Department of Environment and Natural Resources -Division of Water Quality Revised Jan. 2013

WELL CONSTRUCTION RECORD
This form can be used for single or multiple wells
1. Well Contractor Information:
For Internal Use ONLY:
JOHNNY BURR
Well Contractor Name
A - 3098
NC Well Contractor Certification Number
GEOLOGIC EXPLORATION, INC
Company Name
2. Well Construction Permit #:
List all applicable well construction permits (i.e. County, State, Variance, etc.)
3. Well Use (check well use):
Water Supply Well:
❑ Agricultural
El Geothermal (Heating/Cooling Supply)
❑Industrial/Commercial
❑Irrigation
❑Municipal/Public
❑Residential Water Supply (single)
❑Residential Water Supply (shared)
Non -Water Supply Well:
❑✓Monitoring
❑Recovery
Injection Well:
❑ Aquifer Recharge
❑ Aquifer Storage and Recovery
❑Aquifer Test
❑Experimental Technology
El Geothermal (Closed Loop)
❑Geothermal (Heating/Cooling Return)
❑ Groundwater Remedi ation
❑ Salinity Barrier
❑ Stormwater Drainage
❑Subsidence Control
❑ Tracer
❑ Other (explain under #21 Remarks)
4. Date Well(s) Completed: 08/27/19 Well ID#
5a. Well Location:
WRENN ROAD WASTE WATER PLANT
PMW-3
Facility/Owner Name Facility ID# (if applicable)
8828 WRENN ROAD GARNER 27529
Physical Address, City, and Zip
WAKE
County Parcel Identification No. (PIN)
5b. Latitude and Longitude in degrees/minutes/seconds or decimal degrees:
(if well field, one tat/long is sufficient)
35° 38' 20.87" N 78° 34' 59.72"
6. Is (are) the well(s): ©Permanent or ❑Temporary
W
7. Is this a repair to an existing well: ❑Yes or ONo
If this is a repair, fill out known well construction information and explain the nature of the
repair under #21 remarks section or on the back of this form.
8. Number of wells constructed: 1
For multiple injection or non -water supply wells ONLY with the same constnw ion, you can
submit one form.
9. Total well depth below land surface: 16.0 (ft.)
For multiple wells list all depths if different (example- 3@200'and 2@100)
10. Static water level below top of casing: 2'0 (ft.)
If water level is above casing, use "+"
10.0
11. Borehole diameter:
(in.)
12. Well construction method: AUGER
(i.e. auger, rotary, cable, direct push, etc.)
FOR WATER SUPPLY WELLS ONLY:
13a. Yield (gpm) Method of test:
13b. Disinfection type: Amount:
14. WATER ZONES
FROM
TO
DESCRIPTION
ft.
ft.
ft.
ft.
15. OUTER CASING (for multi -cased wells) OR LINER (if ap licable)
FROM
TO
DIAMETER
THICKNESS MATERIAL
ft.
ft.
in.
16. INNER CASING OR TUBING (geothermal closed -loop)
FROM
TO
DIAMETER
THICKNESS
MATERIAL
0.0 ft.
6.0 ft.
2.0 in.
SCH 40
PVC
ft.
ft.
in.
17. SCREEN
FROM
TO
DIAMETER
SLOT SIZE
THICKNESS
MATERIAL
6.0 ft•
16.0 ft•
2.0 m'
.010
SCH 40
PVC
ft.
ft.
in.
18. GROUT
FROM
TO
MATERIAL
EMPLACEMENT METHOD & AMOUNT
0.0 ft.
3.0 ft.
POFRPND1BJTONITE
SLURRY
ft.
ft.
ft.
ft.
19. SAND/GRAVEL PACK (if applicable)
FROM
TO
MATERIAL
EMPLACEMENT METHOD
4.0 ft.
16.0 It
20-40
FINE SILICA SAND
ft.
ft.
20. DRILLING LOG (attach additional sheets if necessary)
FROM
TO
DESCRIPTION (color, hardness, soillrock type, grain size, etc.)
0.0 ft•
1.0 It•
BROWN/BLACK TOPSOIL
1.0 ft•
4.0 ft•
BROWN/WHITE SAND
4.0 ft•
16.0 ft•
BROWN ROCK
ft.
ft.
ft.
ft.
ft.
ft.
ft.
ft.
21. REMARKS
BENTONITE SEAL FROM 3.0 TO 4.0 FEET
22. Certification:
Signature of Certified Well Contractor
09/05/19
D ate
By signing this form, I hereby certify that the well(s) was (were) constructed an accordance
with 15A NCAC 02C .0100 or 15A NCAC 02C .0200 Well Construction Standards and that a
copy of this record has been provided to the well owner.
23. Site diagram or additional well details:
You may use the back of this page to provide additional well site details or well
construction details. You may also attach additional pages if necessary.
SUBMITTAL INSTUCTIONS
24a. For All Wells: Submit this form within 30 days of completion of well
construction to the following:
Division of Water Quality, Information Processing Unit,
1617 Mail Service Center, Raleigh, NC 27699-1617
24b. For Infection Wells: In addition to sending the form to the address in 24a
above, also submit a copy of this form within 30 days of completion of well
construction to the following:
Division of Water Quality, Underground Injection Control Program,
1636 Mail Service Center, Raleigh, NC 27699-1636
24c. For Water Supply & Infection Wells: In addition to sending the form to
the address(es) above, also submit one copy of this form within 30 days of
completion of well construction to the county health department of the county
where constructed.
Form GW-1
North Carolina Department of Environment and Natural Resources -Division of Water Quality Revised Jan. 2013

WELL CONSTRUCTION RECORD
This form can be used for single or multiple wells
1. Well Contractor Information:
For Internal Use ONLY:
JOHNNY BURR
Well Contractor Name
A - 3098
NC Well Contractor Certification Number
GEOLOGIC EXPLORATION, INC
Company Name
2. Well Construction Permit #:
List all applicable well construction permits (i.e. County, State, Variance, etc.)
3. Well Use (check well use):
Water Supply Well:
❑ Agricultural
El Geothermal (Heating/Cooling Supply)
❑Industrial/Commercial
El Irrigation
❑Municipal/Public
❑Residential Water Supply (single)
❑Residential Water Supply (shared)
Non -Water Supply Well:
❑✓Monitoring
El Recovery
Injection Well:
❑ Aquifer Recharge
❑ Aquifer Storage and Recovery
❑Aquifer Test
❑Experimental Technology
El Geothermal (Closed Loop)
❑Geothermal (Heating/Cooling Return)
❑ Groundwater Remedi ation
❑ Salinity Barrier
❑ Stormwater Drainage
❑Subsidence Control
❑ Tracer
❑ Other (explain under #21 Remarks)
4. Date Well(s) Completed: 08/14/19 Well ID#
5a. Well Location:
WRENN ROAD WASTE WATER PLANT
PMW-4
Facility/Owner Name Facility ID# (if applicable)
8828 WRENN ROAD GARNER 27529
Physical Address, City, and Zip
WAKE
County Parcel Identification No. (PIN)
5b. Latitude and Longitude in degrees/minutes/seconds or decimal degrees:
(if well field, one latllong is sufficient)
35° 38' 20.87" N 78° 34' 59.72"
6. Is (are) the well(s): ©Permanent or ❑Temporary
W
7. Is this a repair to an existing well: ❑Yes or ONo
If this is a repair, fill out known well construction information and explain the nature of the
repair under #21 remarks section or on the back of this form.
8. Number of wells constructed: 1
For multiple injection or non -water supply wells ONLY with the same constnw ion, you can
submit one form.
9. Total well depth below land surface:
For multiple wells list all depths if different (example- 3@200'and 2@100)
10. Static water level below top of casing: 22.0 (ft.)
If water level is above casing, use "+"
11. Borehole diameter: 10.0/6.0 (in.)
12. Well construction method: AUGER/AIR
74.0
(ft.)
(i.e. auger, rotary, cable, direct push, etc.)
FOR WATER SUPPLY WELLS ONLY:
13a. Yield (gpm)
Method of test:
13b. Disinfection type:
Amount:
14. WATER ZONES
FROM
TO
DESCRIPTION
ft.
ft.
ft.
ft.
15. OUTER CASING (for multi -cased wells) OR LINER (if ap licable)
FROM
TO
DIAMETER
THICKNESS MATERIAL
ft.
ft.
in.
16. INNER CASING OR TUBING (geothermal closed -loop)
FROM
TO
DIAMETER
THICKNESS
MATERIAL
0.0 ft.
64.0 ft•
2.0 in.
SCH 40
PVC
ft.
ft.
in.
17. SCREEN
FROM
TO
DIAMETER
SLOT SIZE
THICKNESS
MATERIAL
64.0 ft•
74.0 ft•
2.0 m'
.010
SCH 40
PVC
ft.
ft.
in.
18. GROUT
FROM
TO
MATERIAL
EMPLACEMENT METHOD & AMOUNT
0.0 ft.
58.0 ft'
POFRPNDEwTONITE
SLURRY
ft.
ft.
ft.
ft.
19. SAND/GRAVEL PACK (if applicable)
FROM
TO
MATERIAL
EMPLACEMENT METHOD
61.0 ft•
74.0 ft•
20-40
FINE SILICA SAND
ft.
ft.
20. DRILLING LOG (attach additional sheets if necessary)
FROM
TO
DESCRIPTION (color, hardness, soil/rock type, grain size, etc.)
0.0 ft•
1.0 It•
BROWN SAND
1.0 ft•
8.0 ft•
TAN/ORANGE CLAY
8.0 ft•
62.0 ft.
TAN/BROWN SANDY CLAY
62.0 ft•
74.0 ft.
BROWN ROCK
ft.
ft.
ft.
ft.
ft.
ft.
21. REMARKS
BENTONITE SEAL FROM 58.0 TO 61.0 FEET
22. Certification:
Signature of Certified Well Contractor
09/05/19
D ate
By signing this form, I hereby certify that the well(s) was (were) constructed an accordance
with 15A NCAC 02C .0100 or 15A NCAC 02C .0200 Well Construction Standards and that a
copy of this record has been provided to the well owner.
23. Site diagram or additional well details:
You may use the back of this page to provide additional well site details or well
construction details. You may also attach additional pages if necessary.
SUBMITTAL INSTUCTIONS
24a. For All Wells: Submit this form within 30 days of completion of well
construction to the following:
Division of Water Quality, Information Processing Unit,
1617 Mail Service Center, Raleigh, NC 27699-1617
24b. For Infection Wells: In addition to sending the form to the address in 24a
above, also submit a copy of this form within 30 days of completion of well
construction to the following:
Division of Water Quality, Underground Injection Control Program,
1636 Mail Service Center, Raleigh, NC 27699-1636
24c. For Water Supply & Infection Wells: In addition to sending the form to
the address(es) above, also submit one copy of this form within 30 days of
completion of well construction to the county health department of the county
where constructed.
Form GW-1
North Carolina Department of Environment and Natural Resources -Division of Water Quality Revised Jan. 2013

tale Pe5arce5
Attachment 3 Pumping Test Analysis Curves
15

Displacement (ft)
10.
1.
0.1
10.
100.
Time (sec)
pill 1111111,111111,1,111 ull
1000.
1.0E+4
WELL TEST ANALYSIS
Data Set:
Date: 08/27/19 Time: 08:48:48
PROJECT INFORMATION
Company: Eagle Resources
Client: CORPUD
Location: Wrenn road
Test Well: pmw-1
Test Date: 8/25/19
AQUIFER DATA
Saturated Thickness: 21. ft
WELL DATA
Pumping Wells Observation Wells
Well Name
X (ft)
Y (ft)
Well Name
X (ft)
Y (ft)
PMW-1
0
0
° PMW-1
0
0
SOLUTION
Aquifer Model: Unconfined Solution Method: Neuman
T = 7.156 ft2/day S = 0.009562
Sy = 0.5 13 =0.01761

Displacement (ft)
10.
1.
0.1
10.
100.
Time (sec)
1000.
1.0E+4
WELL TEST ANALYSIS
Data Set:
Date: 08/27/19 Time: 09:21:45
PROJECT INFORMATION
Company: Eagle Resources
Client: CORPUD
Location: Wrenn road
Test Well: pmw-2
Test Date: 8/26/19
AQUIFER DATA
Saturated Thickness: 15. ft
WELL DATA
Pumping Wells Observation Wells
Well Name
X (ft)
Y (ft)
Well Name
X (ft)
Y (ft)
PMW-2
0
0
° PMW-2
0
0
SOLUTION
Aquifer Model: Unconfined Solution Method: Neuman
T = 130.9 ft2/day S = 0.003477
Sy = 0.006212 R = 0.0003113

Displacement (ft)
100.
10.
1.
10.
100.
Time (sec)
1000.
1.0E+4
WELL TEST ANALYSIS
Data Set:
Date: 08/27/19 Time: 10:03:50
PROJECT INFORMATION
Company: Eagle Resources
Client: CORPUD
Location: Wrenn road
Test Well: pmw-4
Test Date: 8/26/19
AQUIFER DATA
Saturated Thickness: 50. ft
WELL DATA
Pumping Wells Observation Wells
Well Name
X (ft)
Y (ft)
Well Name
X (ft)
Y (ft)
PMW-4
0
0
° PMW-4
0
0
SOLUTION
Aquifer Model: Unconfined Solution Method: Neuman
T = 1.071 ft2/day S = 0.01199
Sy = 0.5 R = 0.0001824

4
Complete Wrenn Road
Facility Results

Raleigh Water I DRAFT Interim Groundwater Monitoring Results Memorandum
Appendix4—Complete Groundwater Monitoring Results
Appendix 4 — Complete Groundwater Monitoring
Results
November 2019
Sampled By
R. Tart
D. Godfrey
R. Tart D. Godfrey
Date
Time
Weather Condition
Field Data
Depth to Water (ft)
Total Well Depth (ft)
Volume of Water Purg
Before Sampling (gal)
Turbidity (NTU)
pH (standard units)
Temperature (°C)
Conductivity (pmhos/
Laboratory Data
Iron (pg/L)
Manganese (pg/L)
Arsenic (pg/L)
11/21/2019
11/21/2019
11/21/2019 11/21/2019
11:18AM
8:40 AM 12:23 PM 12:10 PM
Clear/Cool/Sunny
24 8
6
21.9
43
20
16
74
d
9.31
6
4.57
25.5
0.48
1.86
1.58
5.08
5.75
5.3
6.03
5.97
16.6
16.8
16.9
17.6
m)
98.9
69.6
129.8
126.2
<60
<60
199
172
90
<50
<50
134
<10
<10
<10
<10
hdrinc.com 555 Fayetteville Street Suite 900 Raleigh, NC 27601-3034
[phone]

Raleigh Water I DRAFT Interim Groundwater Monitoring Results Memorandum
Appendix4—Complete Groundwater Monitoring Results
January 2020
[ Parameter PMW-1
Sampled By
Date
Time
Weather Condition
Field Data
Depth to Water (ft)
Total Well Depth (ft)
Volume of Water Purg
Before Sampling (gal)
Turbidity (NTU)
pH (standard units)
Temperature (°C)
Conductivity (pmhos/
Laboratory Data
Iron (lag/L)
Manganese (lag/L)
Arsenic (lag/L)
R. Tart
R. Tart
R. Tart
D. Godfrey
1/17/2020 1/17/2020 1/17/2020 1/17/2020
10:05 AM 10:49 AM 8:18 AM 10:40 AM
Partly Sunny, Cool
23.8
7.4
5.6
20.5
43
20
16
74
9.4
6.1
6.5
27
0.98
0.48
1.06
2.04
5.87
6.02
6.68
6.07
14
15.1
12.8
15.3
m)
91.6
67.2
110.1
121.2
<60
<60
<60
68
74
<50
<50
<50
<10
<10
<10
<10
hdrinc.com 555 Fayetteville Street Suite 900 Raleigh, NC 27601-3034
[phone]

Raleigh Water I DRAFT Interim Groundwater Monitoring Results Memorandum
Appendix4—Complete Groundwater Monitoring Results
March 2020
[ Parameter PMW-1 PMW-2 PMW-3 PMW-4
Sampled By
Date
Time
Weather Condition
Field Data
Depth to Water (ft)
Total Well Depth (ft)
Volume of Water Purg
Before Sampling (gal)
Turbidity (NTU)
pH (standard units)
Temperature (°C)
Conductivity (pmhos/
Laboratory Data
Iron (lag/L)
Manganese (lag/L)
Arsenic (lag/L)
D. Godfrey
R. Tart
R. Tart
D. Godfrey
3/12/2020 3/12/2020 3/12/2020 3/12/2020
12:06 PM 7:50 AM 12:30 PM
9:59 AM
Cloudy, Cool
20.85
7.5
5.3
16.2
43
20
16
74
d
11
7
5.25
28.5
1.31
0.53
3.49
1.76
5.31
5.93
7.03
6.16
18.2
14.6
14.3
16.8
m)
90.9
71.8
62.2
115.4
<60
<60
141
<60
64
<50
<50
88
<10
<10
<10
<10
hdrinc.com 555 Fayetteville Street Suite 900 Raleigh, NC 27601-3034
[phone]

Raleigh Water I DRAFT Interim Groundwater Monitoring Results Memorandum
Appendix4—Complete Groundwater Monitoring Results
April 2020
Parameter
PMW-1 PMW-2 PMW-3 PMW-4
Sampled By
D. Godfrey R. Tart
R. Tart R. Tart
Date
4/14/2020 4/14/2020 4/14/2020 4/14/2020
Time
10:15 AM 8:30 AM 11:45AM 10:28 AM
Weather Condition
Sunny, Clear, 60's
Field Data
Depth to Water (ft)
20.9
7.7
5.7
16.4
Total Well Depth (ft)
43
20
16
74
Volume of Water Purged
Before Sampling (gal)
10.8
6.5
5.0
28.25
Turbidity (NTU)
0.39
0.23
0.46
1.61
pH (standard units)
7.15
7.32
6.27
6.05
Temperature (°C)
17.6
14.8
15.5
17
Conductivity(pmhos/cm) 92.2
68.8
116.4
110.8
Laboratory Data
Iron (lag/L)
<60
<60
<60
<60
Manganese (lag/L)
70
<50
<50
96
Arsenic (lag/L)
<10
<10
<10
<10
hdrinc.com 555 Fayetteville Street Suite 900 Raleigh, NC 27601-3034
[phone]

Raleigh Water I DRAFT Interim Groundwater Monitoring Results Memorandum
Appendix4—Complete Groundwater Monitoring Results
August 2020
Parameter
PMW-1 PMW-1 D PMW-2 PMW-3 PMW-4
Sampled By
R. Tart
R. Tart R. Tart
R. Tart R. Tart
Date
8/20/2020 8/20/2020 8/20/2020 8/20/2020 8/20/2020
Time
1:25 PM 1:25 PM 12:01 PM 3:15 PM 12:45 PM
Weather Condition
Cloudy, 80's
Field Data
Depth to Water (ft)
22.8
22.8
9.8
6 19
Total Well Depth (ft)
43
43
20
30
74
Volume of Water
Purged Before
Sampling (gal)
9.8
9.8
5.1
5
26
Turbidity(NTU)
0.68
0.68
1.46
1.69
1.5
pH (standard units)
5.93
5.93
6.01
6.63
6.81
Temperature (°C)
19.1
19.1
20.7
19.8
19
Conductivity
(pmhos/cm)
Laboratory Data
Iron (pg/L)
94.5
<60
96.7
<60
73.3
<60
43.5
482
124.5
69
Manganese (pg/L)
88
90
<50
<50
123
Arsenic (pg/L)
<10
<10
<10
<10
<10
hdrinc.com 555 Fayetteville Street Suite 900 Raleigh, NC 27601-3034
[phone]

Raleigh Water I DRAFT Interim Groundwater Monitoring Results Memorandum
Appendix4—Complete Groundwater Monitoring Results
November 2020
Parameter PMW-1 PMW-1 ' PMW-2 PMW-3 PMW-4
Sampled By
D. Godfrey D. Godfrey D. Godfrey D. Godfrey D. Godfrey/
E. Batchelor
Date
11/4/2020 11/4/2020 11/4/2020 11/4/2020 11/4/2020
Time
8:25 AM 8:25 AM 9:08 AM 10:44 AM 12:00 PM
Weather Condition
Clear, 40's/50's
Field Data
Depth to Water (ft) 22.3
22.3
7.8 5.7 18.9
Total Well Depth (ft) 43
43
20
16 74
Volume of Water
Purged Before
Sampling (gal)
10.25
10.25
6
5.25 27
Turbidity (NTU)
1.12
1.12 1.86
0.44 0.72
pH (standard units)
5.32
5.32 5.08
5.65 I 5.87
Temperature (°C)
17
17
18.5
18.1
18.2
Conductivity
(pmhos/cm)
82
82.4
73.6
101.5
129.8
Laboratory Data
Iron (pg/L)
<60
<60
72
73
<60
Manganese (pg/L)
59
61
<50
<50
88
Arsenic (pg/L)
<10
<10
<10
<10
<10
hdrinc.com 555 Fayetteville Street Suite 900 Raleigh, NC 27601-3034
[phone]

Raleigh Water I DRAFT Interim Groundwater Monitoring Results Memorandum
Appendix4—Complete Groundwater Monitoring Results
March 2021
1 Parameter PMW-1 PMW-1 ' PMW-2 PMW-3 PMW-4
Sampled By
D. Godfrey D. Godfrey D. Godfrey D. Godfrey D. Godfrey
Date
3/10/2021
3/10/2021 3/10/2021
3/10/2021 3/10/2021
Time
8:50 AM
8:50 AM 9:22 AM 11:16 AM 1:00 PM
Weather Condition
Sunny, 40's - 60's
Field Data
Depth to Water (ft) 18.3
18.3
6.9 5.9 14.1
Total Well Depth (ft) 43
43
20
16 74
Volume of Water
Purged Before
Sampling (gal)
12.25
12.25 6.5
5 30
Turbidity (NTU)
3.52 3.52
1.52
2.83 0.72
pH (standard units)
5.62
5.62 5.75
6.48 5.85
Temperature (°C)
16.5
16.5
15.5
14.2 19.8
Conductivity
(pmhos/cm)
Laboratory Data
Iron (pg/L)
84.5
97
83.0
132
79.3
199
85.2
123.9
601 <50
Manganese (pg/L)
71
71
16
176
71
Arsenic (pg/L)
<5
<5
<5
<5
<5
hdrinc.com 555 Fayetteville Street Suite 900 Raleigh, NC 27601-3034
[phone]

FY
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Suite 900
Raleigh, NC 27601-3034
[phone]
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