WQ0001740_Appx-D-1 Five-Year Report_20140407

A;tro[it6y Sountl ScianCa !Rlh�vatiUn - S�iUffU.9s
Five -Year Evaluation of Remediation Strategy, Biosolids Fields
at the Neuse River Wastewater Treatment Plant, Wake
County, North Carolina under Permit #WQ0001730
Prepared for:
City of Raleigh Public Utilities Department
April 7, 2014
Eric G. Lappala, P.E., P.H
Eagle Resources, P.A
P.O. Box 11189, 215 W. Moore St, Southport, NC 28461
919.345.1013 /Fax: [phone] [e-mail]

Contents
1 Introduction.......................................................................................................................................
l
1.1 Site Description..........................................................................................................................1
1.2 Remediation Activities...............................................................................................................2
1.3 Assessment of Groundwater Flow and Transport Modeling.....................................................4
1.3.1 Field Sampling Program.....................................................................................................4
1.3.2 Water Balance Modeling....................................................................................................5
1.3.3 Fate and Transport Modeling of NO3 in the Vadose Zone.................................................6
1.3.4 Update and Recalibration of SSA Groundwater Flow Model............................................7
1.3.5 Update and Recalibration of the SSA NO3 Transport Model.............................................7
1.3.6 Time Required to Achieve 2L Compliance by Natural Attenuation..................................8
1.3.7 Candidate Areas for the Resumption of Biosolids Application..........................................8
1.3.8 Lack of Impact on 2L Compliance from Candidate Areas.................................................8
1.3.9 Surface Water Loading Analysis......................................................................................10
1.3.10 Effectiveness of the Updated Groundwater Flow and Transport Model ........................11
2 Groundwater Containment System.................................................................................................20
2.1 Effectiveness of Groundwater Capture by the Active Containment System ...........................25
2.2 Evaluation of Alternatives to the Active Containment System...............................................27
3 Evaluation of Monitored Natural Attenuation................................................................................28
3.1 Evaluation of Alternatives to MNA.........................................................................................29
3.1.1 Enhanced in-situ Biodenitrification(EISBD)...................................................................29
3.1.2 Enhanced Flushing............................................................................................................30
3.1.3 Phytoremediation..............................................................................................................30
4 Evaluation of Subsurface Flow Wetlands.......................................................................................32
4.1 Constructed Wetland Construction, Operation, and Sampling................................................32
4.2 Evaluation of Removal Efficiencies of Wetlands....................................................................32
5 Evaluation of Off -Site Riparian Buffer Restoration.......................................................................36
6 Conclusions.....................................................................................................................................37
6.1 Groundwater Modeling Conclusions.......................................................................................37
6.2 Groundwater Containment System Conclusions.....................................................................37
6.3 Monitored Natural Attenuation Conclusions...........................................................................37
6.4 Subsurface Wetlands Conclusions...........................................................................................38
6.5 Off -Site Riparian Buffer Restoration Conclusions..................................................................38
Attachment L-2014 Annual Monitoring Report ................................................................................39
Attachment 2.—Modeled and Observed Time Histories of NO3 through 2013 for Active
Remediation
Extraction and Observation Wells.......................................................................................
a7

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Attachment 3.—Modeled and Observed Time Histories of NO3 through 2013 for Compliance
MonitoringWells................................................................................................................................108
Attachment 4.—Modeled and Observed Time Histories of NO3 through 2013 for Other Active
MonitoringWells................................................................................................................................118
Attachment 5.—Modeled and Observed Time Histories of NO3 through 2013 for Active Surface
WaterStations.....................................................................................................................................141
ii

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Figures
FigureI.-- Site Map................................................................................................................................3
Figure 2—Typical measured and modeled residual NO3 vertical profile beneath fields that received
historically high levels of PAN in excess of crop uptake requirements.................................................5
Figure 3..-- Measured and Modeled NO3 profile for Field 36...............................................................6
Figure 4.-- . Percolation of water and NO3 below the root zone used as input to the vadose zone
column model and computed concentration in recharge to the groundwater as output from the column
modelfor Field 36...................................................................................................................................7
Figure S. --Comparison of reduction to 2L NO3 Standard under historical (no further loading) and
additional constant loading of 50 Ib/ac/yr starting in 2012 on the selected 385 acres ............................9
Figure 6.—Comparison of reduction to 2L NO3 Standard under historical (no further loading) and
additional constant loading of 50 lb/ac/yr starting in 2012 on the selected 385 acres ............................9
Figure 7.—Comparison NO3 discharge to the Neuse River and its tributaries that drain the CORPUD
fields under historic (no further loading) and additional constant loading of 50 lb/ae/yr starting in
2012 on the selected 385 acres and loading from the SSA models......................................................10
Figure 8. --Modeled and Observed NO3 concentrations in Active Remedial Well RW -3 ..................11
Figure 9. --Modeled and Observed NO3 concentrations in Active Remedial Well RW -8 ..................12
Figure 10. --Modeled and Observed NO3 concentrations in Active Remedial Well RW -8 .............:..12
Figure 11. --Modeled and Observed NO3 concentrations in Active Remedial Well RW -25 ..............13
Figure 12. --Modeled and Observed NO3 concentrations in Active Remedial Well RW -29 ..............13
Figure 13. --Modeled and Observed NO3 concentrations in Compliance Well MW -41 .....................14
Figure 14. --Modeled and Observed NO3 concentrations in Compliance Well MW -42A and MW-
42AR.....................................................................................................................................................15
Figure 15. --Modeled and Observed NO3 concentrations in Compliance Well MW -45 .....................15
Figure 16. --Modeled and Observed NO3 concentrations in Compliance Well MW -52 and MW-52R.
...............................................................................................................................................................16
Figure 17. --Modeled and Observed NO3 concentrations for Surface Water Station SW -1 ................17
Figure 18. --Modeled and Observed NO3 concentrations for Surface Water Station SW -7 ................17
Figure 19. --Modeled and Observed NO3 concentrations for Surface Water Station SW -9 ................18
Figure 20. --Modeled and Observed NO3 concentrations for Surface Water Station SW -28 ..............18
Figure 21.—Modeled and Observed NO3 Concentrations at the end of 2013 in compliance Wells and
SurfaceWater Stations..........................................................................................................................19
Figure 22.-- Groundwater Containment System...................................................................................21
Figure 23. --Monthly flow of groundwater and mass of NO3 delivered to the NRW WTP from the
remedial containment systems..............................................................................................................22
Figure 24.-- Fraction of groundwater withdrawn from each well in the Field 500 containment system.
.....
.........................................................................................................................................................23.
Figure 25.—Time trend in NO3 in Field 500 extraction wells and concentrations in monitoring wells
inor down gradient of field..................................................................................................................24
Figure 26.-- Fraction of groundwater withdrawn from each well in the Field 50 containment system.
...............................................................................................................................................................24
Figure 27.—Time trend in NO3 in Field 50 extraction wells and concentrations in monitoring wells
in or down gradient offield..................................................................................................................25
Figure 28.-- NO3 concentrations in monitoring well MW -117 under NINA, pumping, and
inactivation of pumping in 2015...........................................................................................................26
Figure 29.-- NO3 concentrations in monitoring well MW -203 under MNA, pumping, and
inactivation of pumping in 2015...........................................................................................................26
Figure 30. --Comparison of NO3 mass in inflow and outflow for Wetland A ......................................34
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Figure 31.-- Comparison of NO3 mass in inflow and outflow for Wetland C .....................................35
Figure 32.-- Comparison of NO3 mass in inflow and outflow for Wetland E .....................................35
Tables
Table 1.-- Comparison of design and average actual flow rates from the extraction wells of the
groundwater containment system.........................................................................................................20
Table 2.-- Summary of water and NO3 removed from Field 50 and 500 groundwater containment
systems..................................................................................................................................................22
Table 3.-- Comparison of trend in observed and modeled NO3 at MMA Stations..............................28
Table 4.-- Mass of NO3 in inflow to and outflow from wetlands A, C, and E .....................................33
Table 5.—Mass removal of NO3 by the wetlands since becoming fully operational and average rate
ofremoval since July 2013................................................................................................................... 34
iv

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1 Introduction
This report has been prepared for the City of Raleigh Public Utilities Department (CORPUD) to
provide the five-year evaluation of the groundwater remediation strategy being implemented by
CORPUD at its Neuse River Waste Water Treatment Plant (NRW WTP) pursuant to the variance
from the requirements of 15A NCAC .02L granted on January 15, 2010 by the North Carolina
Environmental Management Commission (Variance). The remediation strategy addresses nitrate
contamination of groundwater and surface water associated with application of biosolids to
agricultural fields (the Site) that serve the NRW WTP. The NRW WTP is located at 8500 Battle
Bridge Road in Raleigh, Wake County, North Carolina (Figure 1).
1.1 Site Description
The Site comprises approximately 1466 acres of mostly contiguous farmland owned by CORPUD
that is divided into numbered fields. The Site is surrounded by residential properties, private
farmland, and state-owned farmland. A 3.6 -mile reach of the Neuse River forms the northern and
eastern boundaries of the site, and the river bisects the northeastern portion of the site. The southern
portion of the site is bounded by Beddingfield Creek.
The Site comprises rolling hills that are drained by natural and constructed drainage ways which all
drain to either the Neuse River of Beddingfield Creek. Topography ranges from a high of 140 ft. to
350 ft. NAVD88. The Site is underlain by moderately to well -drained soils developed on saprolite,
which is developed from the weathering of the underlying consolidated granitic bedrock.
The fields at the Site historically received biosolids from the NRW WTP from 1980 through
September 2002 under land application Permit #W00001730 (Permit). The number of active fields
varied during this period. Application to Fields 1, 2, and 3 was ceased in 1998 and these fields were
converted into a police training facility. Waste Corporation of America now owns formerly leased
Fields 100, 101, 102, 522, 523, and 524 and that property has been developed as a construction and
demolition debris landfill. Field 600 on the south side of Beddingfield Creek is no longer leased by
CORPUD. All of the remaining fields are owned by CORPUD as shown in Figure 1.
Groundwater monitoring required under the Permit showed exceedances of the NCAC 2L standard of
10 mg/l for nitrate (NOO in the vicinity of the permit compliance boundary and land application of
biosolids to all fields was suspended in September 2002. Extensive site investigations have been
performed of groundwater and surface water conditions and water quality since 2002.2.3.
ENSR, 2002, Comprehensive Site Assessment (CSA) Report, City of Raleigh Neuse River Wastewater Treatment Plant,
Raleigh, NC.
Z ENSR, 2003, Supplemental Site Assessment Report (SSA) , City of Raleigh Neuse River Wastewater Treatment Plant,
Raleigh, NC.
3 Eagle Resources, 2007, Assessment of Irrigation Requirements City of Raleigh Phase III Sprayfields

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1.2 Remediation Activities
A revised Corrective Action Plan based upon the CSA and SSA was prepared and submitted to
the Division in November 20054. That plan included the following activities:
• Groundwater Containment System;
• Monitored Natural Attenuation;
• Constructed Subsurface Flow Wetlands, and
• Off -Site Riparian Buffer Restoration.
This 5 -year evaluation assesses the effectiveness and performance of these activities as required by
the following language in paragraph 4f (page 15 of the Variance):
" Beginning in January 2014 and every five years thereafter, Raleigh shall evaluate the effectiveness
of the overall remediation strategy required herein to determine if new or additional treatment
technologies exist that could be implemented cost effectively while maintaining safety of human
health and the environment. These evaluations and reports shall also include review of modeling
results against observed data. Collection of additional data and information to improve model
calibration or to better evaluate potential treatment technologies may be requested by the DWQ. "
This evaluation relies on data and information provided by CORPUD in the 2013 Annual Monitoring
Report, which is included as Attachment 1. The annual reports conform to the requirements of
Attachment 2 to the Variance (See Appendix A to Attachment 1 to this report).
Figure 1 shows the location of all monitoring stations as well as the location of the subsurface
wetland sites. This evaluation also relied on a review of the 2013 Annual Monitoring Reports.
4 ENSR, 2005, Revised Corrective Action Plan, City of Raleigh, Neuse River Wastewater Treatment Plant, Raleigh, NC.
'Annual Monitoring Report CY2013.pdf
2

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1.3 Assessment of Groundwater Flow and Transport Modeling
The groundwater flow and transport model from Eagle Resources' latest report on the resumption of
biosolids6 was used for this evaluation. The model was updated by refining the model grid from a 60
ft x 60 ft square mesh to 20 ft x 20 ft over the areas that are centered on Fields 50 and 500 so as to
better assess the geometry of the zones of groundwater capture by the extraction wells that comprise
the Groundwater Containment System.
The biosolids application model was developed from the model initially constructed for the CSA1 and
SSA2. The biosolids application model was updated based upon the following:
• Field Sampling of NO3 vs. depth in 30 fields;
• Water Balance Modeling to evaluate water percolation from the soil zone;
• Fate and Transport Modeling of NO3 in the vadose zone above the watertable;
• Update and Re -calibration of the SSA Groundwater Flow Model; and
• Update and Re -calibration of the SSA NO3 Transport Model.
The updated model was used to assess the following scenarios:
The likely time required for NO2 to decline to the 2L Standard at the compliance boundary via
natural attenuation following the cessation of biosolids application in 2002;
Identification of fields from which groundwater flow paths do not cross the compliance
boundary as potential candidates for resumption of biosolids application; and
Demonstration that the resumption of biosolids on the candidate fields would not impact the
time to achieve 2L compliance anywhere along the compliance boundary.
The updated model was also used to demonstrate likely changes in loading to the Neuse River and its
tributaries for the conditions of no additional loading and the combination of that condition and the
unlikely case of PAN being applied in excess of plant uptake requirements on the candidate fields for
the resumption of biosolids application.
1.3.1 Field Sampling Program
Field sampling of 30 out of the 77 permitted CORPUD fields during July and August 2011 to
document the NO3 concentration vs. depth profiles in at least one location in each sampled field and
to provide samples to measure hydraulic properties of the soil and vadose zones:
The field sampling program comprised NO3 analyses of samples of homogenized 3 -foot intervals
from continuous cores obtained from borings installed to refusal using push technology. The fields
sampled were expanded beyond the 18 prototype fields to include at least one boring in each of 30 of
the 78 permitted fields. The field sampling program included the following:
• Installation and continuous coring of 58 borings;
• Completion of 11 of the borings that encountered shallow groundwater as temporary
piezometers;
• Field analysis of NO3, Temperature, pH, and Specific Conductance on 275 soil samples.
• Analysis of 61 split soil samples for NO3 by the CORPUD laboratory;
s Eagle Resources, 2012, Method and Results Demonstrating the Acceptability of Resuming Biosolids Application to
Selected Areas of the City of Raleigh Neuse River Waste Water Treatment Plant Fields
ll

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• Two rounds of sampling and field and laboratory analysis for NO3 from the temporary
piezometers;
• Analysis of 269 split soil samples for moisture content and 74 split soil samples for particle
size distribution by the NCSU Soil Properties Laboratory;
• Field measurements of in-situ hydraulic conductivity at the 14 boring locations at 2 depths;
• Collection of undisturbed core samples from the depths and locations used for hydraulic
conductivity tests; and
• Analysis of undisturbed soil core samples for 4 -point soil moisture retention curves by the
NCSU laboratory.
The results of the field sampling program demonstrate that a significant amount of residual nitrogen
in the form of NO3 is present in groundwater in the vadose zone above the watertable beneath most of
the CORPUD fields. In general, the pattern of NO3 vs. depth shows increases from 10 to 20 mg/1 at
the surface and from 50 to greater than 100 mg/1 at the watertable as shown in Figure 2. This pattern
is the result of slow flushing of the vadose zone by the combination of percolation of rainfall below
the root zone since biosolids application was stopped in 2002 (and irrigation on some fields since
2007). Fields that received limited to very low historical biosolids applications show an exception to
this pattern with low NO3 concentrations decreasing slightly with depth.
0-
5-
W 10 -
L
Y
a
p 15 -
20 -
25 -
Field 36 (Irrigated)
1.0 10.0 100.0
[NO3] in Soil Moisture or Groundwater, mg/1)
Figure 2—"typical measured and modeled residual NO3 vertical profile beneath fields that received historically high levels of
PAN in excess of crop uptake requirements.
1.3.2 Water Balance Modeling
The daily water balance model previously developed to assess irrigation methods to limit leaching of
NO3 from the soil zone under the permitted Phase III irrigation ffelds3 was expanded to cover the area
Notes:—
Multiplier for 140
Ib/ac/yr=1.0
Multiplier for 200
Ib/ac/yr = 1.0 based on
Transport Model
calibration
I
58-36-1
♦ SB -36-1 CORPUD Lab
SSB -36-2
♦ 5B-36-2 CORPUD Lab
® Piezometer 36-1
—Groundwater Level (PZ -36-1)
1.0 10.0 100.0
[NO3] in Soil Moisture or Groundwater, mg/1)
Figure 2—"typical measured and modeled residual NO3 vertical profile beneath fields that received historically high levels of
PAN in excess of crop uptake requirements.
1.3.2 Water Balance Modeling
The daily water balance model previously developed to assess irrigation methods to limit leaching of
NO3 from the soil zone under the permitted Phase III irrigation ffelds3 was expanded to cover the area

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covered by the Groundwater Flow Model. Climatic data for the model provided a daily record of
precipitation and temperature data for the 1950 through 2010 period. Soil hydraulic property data
irrigation study were augmented by laboratory measurements on samples from the Field Sampling
Program.
The updated water balance model was used to generate daily, monthly, and annual average
percolation rates below the root zone for each of the 40 sub -watersheds which were used for input to
the Vadose Zone Fate and Transport Models and to generate 1979 to 2010 average recharge rates to
groundwater by sub -watershed to recalibrate the updated Groundwater Flow Model.
1.3.3 Fate and Transport Modeling of NO3 in the Vadose Zone
Fate and transport models for NO3 using vertical columns from the base of the soil zone to below the
watertable were constructed for each field to: 1) analyze the measured residual NO3 concentrations in
the vadose and shallow groundwater zone; 2) evaluate the likely time required to flush the residual
NO3 from the vadose zone; and 3) and to generate time -varying NO3 concentrations in recharge as
source terms to recalibrate for the Updated Transport Model.
Water input to the models was average annual rate of percolation below the root zone from the water
balance model for each of the ears from 1950 to 2010. NO3 input in the percolating water was
computed from the difference between applied PAN from Table G-3 of the SSA and an assumed
agronomic plant uptake rate of 200 /b/ac/yr which is close to the average of 190 ]b/ac/yr in the Permit
for the crops grown in rotation in the fields. The comparison of the NO3 vs. depth profiles computed
with the models were compared to the measured profiles as exemplified in Figure 3 demonstrated
that the models provide a reasonable representation of field conditions and could therefore be used
for objectives 2) and 3) for these models.
20
25
Field 36
1.0 10.0 100.0
[NO3] in Soil Moisture or Groundwater, mg/1)
Figure 3 ---Measured and Modeled NO3 profile for Field 36
Analyses of the vertical NO3 profiles with the vertical col demonstrate that, under climatic and
irrigation conditions since the cessation of applications in 2003, more than 15 to 20 years will be
C
iezometer 36-1
roundwater Le I (PZ -36-1)
oil
FIE
1.0 10.0 100.0
[NO3] in Soil Moisture or Groundwater, mg/1)
Figure 3 ---Measured and Modeled NO3 profile for Field 36
Analyses of the vertical NO3 profiles with the vertical col demonstrate that, under climatic and
irrigation conditions since the cessation of applications in 2003, more than 15 to 20 years will be

'We Pa5arce5
required to flush the residual NO3 from the vadose zone. This is the result of the low permeability of
the Saprolite and Partially Weathered Rock (PWR) that comprise the vadose and groundwater zones
above the underlying fractured bedrock. Figure 4 illustrates this time lag for Field 36. As shown in
Figure 4, transport of NO3 under transient variably saturated flow and NO3 also results in the
attenuation of the maximum concentration and variations in excess PAN applied to the soil as well as
a significant lag between from the cessation of applications and the flushing of the vadose zone.
600
500
400
G
m
E 300
m
O
Z
200
100
Field 36 NO3 Concentration in Recharge to Watertable
12/31/70 12/31/90 12/31/10 12/31/30 12/31/50
Figure 4.--. Percolation of water and NO3 below the root zone used as input to the vadose zone column model and computed
concentration in recharge to the groundwater as output from the column model for Field 36.
1.3.4 Update and Recalibration of SSA Groundwater Flow Model
The three-dimensional groundwater flow model developed for the SSA was updated to include data
collected from borings and wells installed since the SSA, as well as the two active remedial pumping
systems located adjacent to Fields 50 and 500. The Updated Groundwater Flow Model was
successfully recalibrated to average water levels computed from 437 water levels measured in 110
observation wells from 2000 through 2011.
Model calibration was achieved by manual and automated fitting by adjusting the isotropic hydraulic
conductivity of the Saprolite and PWR layers in the model. The degree of fit between modeled and
observed water levels as measured by the Normalized Root Mean Square Error was 5.9%, which is
less than the industry standard and NCDENR guidance level of 10% and less than the 6.7% achieved
by the SSA Groundwater Flow Model.
1.3.5 Update and Recalibration of the SSA NO3 Transport Model
The transport model was used in the SSA to compare modeled and measured NO3 concentrations in
observation wells that were available as of 2002. Based upon criteria provided by NC D WQ an
IN
Column Model
fit- 11
In to Transport Model
i
12/31/70 12/31/90 12/31/10 12/31/30 12/31/50
Figure 4.--. Percolation of water and NO3 below the root zone used as input to the vadose zone column model and computed
concentration in recharge to the groundwater as output from the column model for Field 36.
1.3.4 Update and Recalibration of SSA Groundwater Flow Model
The three-dimensional groundwater flow model developed for the SSA was updated to include data
collected from borings and wells installed since the SSA, as well as the two active remedial pumping
systems located adjacent to Fields 50 and 500. The Updated Groundwater Flow Model was
successfully recalibrated to average water levels computed from 437 water levels measured in 110
observation wells from 2000 through 2011.
Model calibration was achieved by manual and automated fitting by adjusting the isotropic hydraulic
conductivity of the Saprolite and PWR layers in the model. The degree of fit between modeled and
observed water levels as measured by the Normalized Root Mean Square Error was 5.9%, which is
less than the industry standard and NCDENR guidance level of 10% and less than the 6.7% achieved
by the SSA Groundwater Flow Model.
1.3.5 Update and Recalibration of the SSA NO3 Transport Model
The transport model was used in the SSA to compare modeled and measured NO3 concentrations in
observation wells that were available as of 2002. Based upon criteria provided by NC D WQ an

acceptable level of agreement was achieved by that model. However, owing to the limited number of
available measured values, no attempt was made to calibrate the SSA transport model. The updated
Transport Model was successfully calibrated using more than 2000 NO3 analyses on groundwater and
surface water from the ongoing CORPUD groundwater monitoring program that was collected since
biosolids applications ceased in 2003 until 2010.
Calibration of the Transport model was achieved by applying multipliers to the NO3 output from the
column models for each field. Multipliers ranged from 0.01 to 4, with an approximate average of 1.0.
Calibration did not involve any spatial variation in the transport parameters that determine the
velocity of NO3 movement (effective porosity) or the pattern of spreading in groundwater caused by
variations in from the mean direction of flow (hydrodynamic dispersion). Values of these
parameters were left at values used for the SSA transport model.
1.3.6 Time Required to Achieve 2L Compliance by Natural Attenuation
Analyses with the updated and calibrated Groundwater Flow and Transport Models showed 1) that it
will take more than 30 years for NO3 concentrations the Saprolite and PWR zones to be reduced to
less that the 2L Standard everywhere along the compliance Boundary; and 2) that significant residual
concentrations can remain in groundwater beneath the central portions of the field areas that will
likely never reach the Compliance Boundary, because such groundwater discharges to surface water
tributaries to the Neuse River that drain the fields.
1.3.7 Candidate Areas for the Resumption of Biosolids Application
An initial estimate of the fields or portions of fields from which any NO3 leaching below the root
zone and entering the groundwater would not reach the Compliance Boundary was performed by
steady-state groundwater flow path analyses with the calibrated Groundwater Flow Model. A flow
path was generated from the center of each model computational cell falling within a field until it
reached a surface drainage or had traveled for 50 years. Areas of fields that had no flow paths
crossing the compliance boundary were identified as likely candidates for the resumption of biosolids
application.
The updated and calibrated Transport model was then run for 50 years with an assumed loading of
PAN to the candidate areas of 50 lb/ac/yr in excess of agronomic uptake rates to identify areas where
the NO3 concentration was greater than the 2L Standard in any model layer outside the Compliance
Boundary. The candidate areas were manually adjusted and the model re -run until an approximate
maximum loading area comprising 385 acres was derived from which the constant rate of excess NO3
leaching at 50 mg/I resulted in no exceedances of the 21, Standard anywhere along the Compliance
Boundary after 50 years.
These analyses also showed that a quasi -steady state NO3 distribution is reached in approximately 30
to 40 years. That is, the outer NO3 boundary defined by the 10 mg/12L Standard does not expand
further after this period. This is the result of dilution by recharge within the modeled area that does
not include the excess NO3 application areas.
1.3.8 Lack of Impact on 2L Compliance from Candidate Areas
The very conservative analysis used to identify candidate areas for the resumption of biosolids
showed that resuming biosolids application on approximately 385 of the 999 acres of permitted
CORPUD fields will have no significant effect on the time it will take to reach 2L Standard along the
Compliance Boundary. This is because no groundwater emanating from beneath any of the identified
candidate areas moves across the compliance boundary before discharging to surface drains. This
was confirmed by comparing the modeled NO3 concentrations from 1979 to 2060 at approximately

,�,Ije P'e3a.Yce3
100 more or less equally spaced observation locations along those portions of the Compliance
Boundary that were down -gradient or cross -gradient from any field with and without the application
of the 50 lb/ac/yr of excess PAN to the candidate areas. Figures 5 and 6 illustrate the lack of
significant time to compliance from this analysis.
50
40
R
CL
E
0
.� _30
3 E
a
v
C 40
R C
O
O m
Q
10
C
0
Z
0
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49 Dec -59
Figure 5.—Comparison of reduction to 21. NO3 Standard under historical (no further loading) and additional constant loading
of 50 Ib/ac/yr starting in 2012 on the selected 385 acres.
50
c
40
R
CL
E
O
U
S 10
M
0
z
rel
1111
TO
IN
A Historic Loading and Residual
A Historic Loading and Residual
:1111
ist Residual Plus 50
H oric Loading and
lb/ac/yr no impact loading
Historic Loading and Residual
Plus 50 lb/ac/yr no impact
loading
IN
oil
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49 Dec -59
Figure 5.—Comparison of reduction to 21. NO3 Standard under historical (no further loading) and additional constant loading
of 50 Ib/ac/yr starting in 2012 on the selected 385 acres.
50
c
40
R
CL
E
O
U
S 10
M
0
z
rel
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49 Dec -59
Figure 6.—Comparison of reduction to 21, NO3 Standard under historical (no further loading) and additional constant loading
or50 Ib/ae/yr starting in 2012 on the selected 385 acres.
z
1111
TO
IN
A Historic Loading and Residual
:1111
ist Residual Plus 50
H oric Loading and
lb/ac/yr no impact loading
IN
oil
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49 Dec -59
Figure 6.—Comparison of reduction to 21, NO3 Standard under historical (no further loading) and additional constant loading
or50 Ib/ae/yr starting in 2012 on the selected 385 acres.
z

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1.3.9 Surface Water Loading Analysis
The updated groundwater flow and transport model demonstrates that with no resumption of
biosolids applications the maximum loading rates of NO3 to the Neuse River and its tributaries that
drain the CORPUD fields will be less than that predicted by the SSA model, but the rate at which
loading declines over time will be slower. This is the result of using the more realistic time -varying
source term from this study that accounts for the attenuation and delay of NO3 in recharge through
the vadose zone.
(For the purposes of updating the model, it was necessary to replicate the original SSA model using
newer software.)
Figure 7 also shows, for the replicated SSA model and the updated model, the NO3 flux to the Neuse
River and tributaries in excess of the flux that would occur if the NO3 concentration in groundwater
everywhere within the modeled area, including at the Compliance Boundary, equaled the 10 mg/1 NC
2L standard for NO3. These values, as determined using the original SSA model, were the basis for
establishing the nitrogen debit in CORPUD's NPDES permit, which is intended to offset the nitrogen
flux to surface water resulting from excess NO3 concentrations in groundwater at the site.
160,000 -
140,000 -
120,000
N
Y
R
s 100,000
H
v
c
80,000
w
cc
d
� 60,000
Z
R
20,000
C
Q
Jan -80 Dec -89 Jan -00 Dec -09 Jan -20 Dec -29 Jan -40 Dec -49 Jan -60
Figur e 7.—Comparison NO3 discharge to the Neuse River anti its tributaries that drain the CORPUD fields under historic (no
further loading) and additional constant loading of 50 Ib/ac/yr starting in 2012 on the selected 385 acres and loading from the
SSA models.
lul
—Replica of SSA Model
—Replica of SSA Model - Difference between
SSA Model and 10 mg/loading used for Debit
—Updated Model Baseline, no Additional
Loading
—Updated Model - Difference Between No
Additional Loading and 10 mg/I loading
♦ Debit Values from Permit
- —
Jan -80 Dec -89 Jan -00 Dec -09 Jan -20 Dec -29 Jan -40 Dec -49 Jan -60
Figur e 7.—Comparison NO3 discharge to the Neuse River anti its tributaries that drain the CORPUD fields under historic (no
further loading) and additional constant loading of 50 Ib/ac/yr starting in 2012 on the selected 385 acres and loading from the
SSA models.
lul

Figure 7 also includes the exact debit values that have been established in the NPDES permit through
2017 based on the original SSA model). Figure 7 shows that the Permit debit has been and remains
until at least203O, substantially higher than the currently modeled excess nitrogen load to surface
water, even before the conservatism of the model and the debit methodology are accounted for.
1.3.10 Effectiveness of the Updated Groundwater Flow and Transport Model
For this 5 -year evaluation, the comparison between measured and observed concentrations has been
updated to include NO3 analyses collected between 2010 and 2013. The effectiveness of the model
as an analysis tool is illustrated by the comparison of observed and modeled concentrations.
1.3.10.1 Effectiveness of Modeled NO3 Concentrations for the Active Remedial System
This comparison is shown in Figures 8 through 10 for the Active Remediation System in Field 500
for the three wells (RW -3, RW -8, and RW -15) that are capturing the majority of the groundwater
from that system. Figures 11 and 12 show the comparison for the two wells (RW -25 and RW -29)
that are capturing the majority of the flow from the Field 50 system.
Plots for all the 29 Active Remediation Wells are included as Attachment 2.
100
I I i-
i
f-
fI
i
I
Upgradient Fields:
500, 201
1 4 -7 --
Dec -79
RW -3
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39
Figure 8.--NIodeled and Observed NO3 concentrations in Active Remedial Well RW -3.
Dec -49
II

100
1
�a�e �E'esav'ces
RW -8
_ ■ RW -8 Observed t
I _ _ —Model
_- — - - - --�—I— --I --- I - - - — J- --'-
Upgradient Fields: I f
500,201
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
Figure 9. --Modeled and Observed NO3 concentrations in Active Remedial Well RW -8.
RW -15
100 .. _ . _ ... ..._._, _
Upgradient Fields: ■ RW -15 _
Observed
—Model }'
E
M I—
Q
Z
' I I�lill I I', ' ii I 111
1 1 --
Dec-79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
Figure lo. --Modeled and Obsenwed NO3 concentrations iu Active Remedial Well RW -8.
12

100
R
E
.; 10
0
z
tri
Upgradient Fields
50
�a�e,('esa.Yces
RW -25
1 4#
Dec -79
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
Figure 11. --1 lodeled and Obsen ed NO3 concentrations in Active Remedial Well RW -25.
RW -29
R
100
1 .._..._.. t.4._�..-.-.yam
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
Figure 12. --Modeled and Observed NO3 concentrations in Active Remedial Well RW -29.
We conclude from this evaluation that the model reasonably represents NO3 concentrations in the
remedial wells and that it can be used as a reasonable tool to assess the effectiveness of the hydraulic
capture of groundwater from Fields 50 and 500.
13

.ea* &5arce5
1.3.10.2 Effectiveness of Modeled NO3 Concentrations for Compliance Wells
Observed values in the compliance wells provide the measure of the degree to which concentrations
have changed as the result of natural attenuation since the cessation of biosolids application in 2003.
Modeled concentrations demonstrate the ability of the model to represent those concentrations as well
as their likely future reductions. Figures 13 through 16 compare observed and modeled NO3
concentrations in the Compliance Wells. Plots for all the Compliance Wells are included in
Attachment 3. Wells shown with "R" appended to the well number are replacement wells that were
installed tat the request of DWR to deeper depths where the original wells were often too dry to
obtain a sample.
100
MW -41 (Compliance Well)
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
Figure U.—Modeled and Observed NO3 concentrations in Compliance well MW -dl.
14

�aje K'ff. � a rce5
MW-42AR and MW -42A (Compliance Wells)
100 --- - -�. --: --. — —------ --..y-- 77--
III
-�.
IIIMW-42AR
j Observed . �, l_. r1�i' ♦ MW -42A Observed
- --I-
E --Model
0 10 -,L -
milli-
..
-
LUpgradient - -
Fields:
I�
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
Figure 14. --Modeled and Obserwd NO3 concentrations in Compliance Well NIR• -42A and MNV-42AR.
100
1
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19
Figure 15.--Nlaleled and Obscned NO3 concentrations in Compliance Well NIRV-45.
MW -45 Compliance Well
Dec -29 Dec -39 Dec -49
15
�I
T.
I
i
■
-
- -
-I_-
0 MW -45
-
-
-
- Observed -
-I
—Model
Dec -29 Dec -39 Dec -49
15

100
m
E
m
z 10
z
dale eesarces
MW -52R and MW -52 (Compliance Wells)
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
Figure 16.--Olodeled and Obsemed NO3 concentrations in Compliance well NiW-52 and Mw -5212.
We conclude from comparing the plots of observed and modeled concentrations in compliance wells
that the model provides a reasonable tool to assess the likely future reductions in NO3 at the
compliance boundary as the result of natural attenuation. The modeled concentrations for the last
several years generally are in good agreement or are higher than the observed values.
1.3.10.3 Effectiveness of Modeled NO3 Concentrations in Surface Water
The updated groundwater flow and transport model had previously been used to demonstrate the
discharge of NO3 emanating from the fields to surface drainage and to the Neuse River as discussed
in Section 1.3.9 of this evaluation. To assess the reasonableness of these modeled discharges we
evaluated the NO3 concentrations in surface water stations that are part of the required monitoring
under the Permit and compared them to the modeled concentrations. Figures 17 through 20
compare the modeled and observed values for 4 stations that monitor drainages that receive
groundwater discharge from multiple fields.
16

100
E 10
M
z
z,
1
Contributing M I I --
Fields: '
■ SW -1 Observed
—Model
,�4e&afces
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
Figure 17.-Modcled and Observed NO3 concentrations for Surface Water Station SW -1.
SW -7
100
1
Contributing i II�Ii�!I� �I?IIIIIIjIiI) Ili
Fields: =i
28,29 -
-- - - J -- -
■ SW -7 -
Observed
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29
Figure 18.--Modcled and Obscwed NO3 concentrations for Surface Water Station SW -7.
Dec -39 Dec -49
17

SW -9
100
'We pk--am-5
1
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
Figure 19. --modeled and Observed NO3 concentrations for Surface Water Station SW -9.
100
E 10
m
O
z
1
SW -28
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
Figure 20.--Modcled and Observed NO3 concentrations for Surface Water Station SW -28.
Plots of the modeled and observed NO3 concentrations for all 24 surface water stations are included
in Attachment 5.
18

)WI- ('e5arc_5
We conclude from the comparison of modeled and observed concentrations in surface water drains
that the model is a reliable tool to assess present and likely future NO3 loading to surface water.
1.3.10.4 Effectiveness of Modeling at Compliance Wells and Surface Water Stations
The observed and modeled concentrations of NO3 in the Compliance Wells and Surface Water
Stations on drains that intercept groundwater from the fields at the end of 2013 are shown in Figure
21.
150
140
130
5 120
E
ni 110
0
100
� 90
80
° 70
C 60
U So
M
40
a 20
10 .
■■■■■■RNM■■■■■
M
■■■■■■■.,■■■■M
■
■
ComplianceWells
0 Surface Water StationsLinear (Compliance Wells)■
!■■/N%
%■1
NPIFII
Mi■■■1
�,1�i1■�■■■■■■■■■■
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
Observed NO3 Concentration as of 12/31/2013, mg/I
Figure 21. Modeled and Observed NO3 Concentrations at the end of 2013 in compliance wells and Surface Water Stations.
Comparison of the slopes of the best fit regression line with the line of equality in Figure 21 shows
that modeled concentrations in Compliance Wells are approximately 65% higher than observed
values and that modeled concentrations at Surface Water Stations are approximately 25% higher than
observed values.
Based upon this assessment the model predicts higher concentrations at the compliance boundary and
longer times to 21, compliance at that boundary than observed values would indicate. This analysis
also demonstrates that the model over predicts NO3 concentrations in surface water drains which
discharge to the Neuse River, and consequently that the analysis of such discharge discussed in
Section 1.3.9 used to compute the Debit in the Permit is very conservative.
19

��%l.'esarrces
2 Groundwater Containment System
Active groundwater remediation at the Site includes groundwater capture and containment systems
for Fields 50 and 500. These systems comprise extraction wells completed at the locations and
depths determined by modeling in the Revised Corrective Action Plan to capture groundwater
containing NO3 beneath up -gradient fields and areas and to prevent the migration of such
groundwater into areas down gradient of the systems.
The Field 50 containment system comprises 7 extraction wells along the compliance boundary for
that field, and the Field 500 system comprises 22 extraction wells along the compliance boundary for
that field as shown in Figure 22. Water produced from the extraction wells from both systems is
collected at a pump station located along Old Baucom Road and discharged to the head works of the
NRW WTP for treatment at the facility. Both containment systems became active in January 2007
and have been operating continuously since that time.
Table 1 shows the design and measured average flow rates from each of the extraction wells. It is
apparent from this table that the majority of the flow from the containment system comes from the 7
wells of the Field 50 system. The actual average flow rate was 106% of the design rate for Field 500,
121% of the design rate for Field 50, and 110% of the design rate for the total system.
Field
Well
Actual
Flow
Actual/
Design
Field
Well
Design
Flow
Actual
Flow
Actual/
Design
Gal/day
%
gal/day
gal/day
%
500
RW -1
V3733
3901
105%
500
RW -17
15
11
75%
RW -2
1129
125%
RW -18
284
247
87%
RW -3
4208
106%
RW -19
494
458
93%
RW -4
486
532
109%
RW -20
808
1008
125%
RW -5
688
487
71%
RW -21
329
313
95%
RW -6
1010
1967
195%
RW -22
337
324
96%
RW -7
2244
1854
83%
Total Field 500
22911
24388
106%
RW -8
3351
3803
114%
50
RW -23
823
863
105%
RW -9
1 67
65
97%
RW -24
359
297
83%
RW -10
75
79
106%
RW -25
2693
3190
118%
RW -11
157
109
70%
RW -26
396
536
135%
RW -12
494
344
70%
RW -27
718
661
92%
RW -13
254
173
68%
RW -28
299
1021
341%
RW -14
284
221
78%
RW -29
1 2633
3026
115%
RW -15
2827
3062
108%
-Total 50
7921
9595
121%
RW -16
105
93
89%
Total System
1 30833
1 33983
110%
'ruble I.-- Coin parisoit of design and average actual flow rates from the extraction wells of the groundwater containment
system.
20

V_ � ry
/ e
Ry \;` V i de da N
N m a 3
deR 2 n v
o a E
I° < E
c e > E H m
de
/ ! re m w
A 3 1
a a O
c
3 Z
0 3
a a
m' Q
do
dada
as
ad
as
re
ed
City of
Raleigh
Eagle Resource. P.A.
P.O. Box 11189 Public
Southport, NC 28481 Utilities
919.3451013 — .
ovalgn a.W anarccommenaaEuna btludcd nerds aro promaea az. meMr
Would not be said for trial design. Rely only an fined, berCaopy moderate be
Nd. 24001.1nwnanis original egnnare and sem.
ae: GLRamobi
Y25H4 ..a the af6, tsiptim. and Ici6eEy of end reseyedy sWtedrt'____..____._
Figure
2

Based upon the latest reporting data from CORPUD7, the containment systems in Fields 50 and 500
collectively removed a total of 75 million gallons of groundwater and 18,000 lb. of NO3 from system
startup in January 2008 through January 2014 as shown in Table 2.
Year
Flow to
NRWWTP
NO3 to
NRWWTP
M al! r
Lb/yr
2008
6.73
1756
2009
11.71
2558
2010
13.63
3245
2011
12.89
3168
2012
13.34
3172
2013
15.53
3467
2014
1.31
305
Total
75.15
17670
Table 2.-- Summary of water and NO3 removed from Field 50 and 500 groundwater containment systems.
The monthly volumes of groundwater and mass of NO3 delivered to the NRW WTP from January
2010 through January 2014 are shown in Figure 23. Regression analysis using a 99% significance
value of these data show that the concentration of NO3 delivered to the NRW WTP has only slightly
changed at a rate of 0.53 mg/l/year and has averaged 30.4 mg/I over this time period. Based upon
average flow rates and concentrations from the Fields 50 and 500 containment systems for the period
from January 1, 2008 through January 2014, the flow weighted average concentration of NO3
delivered to the plant is 33.6 mg/l.
�If
350 -
300
250
R
200
°
\ —\150
� m
Y
m 100
a
° 50
O
z 0
m
r
10 20 30 40 50
Months since 1/1/2008
60 70
1.60
1.40
1.20
1.00
M
0.80 0
E
0.60
0.40 m
0.20 3
0.00
Figure 23.--Nfonthly flow of groundwater and mass of NO3 delivered to the NRWWTP from the remedial containment systems.
' Sludge -GW Monthly Report January 2014.xls provided by CORPUD
22
WW
�11131
■
IN Lb NO3
A Flow, rngal/nio—Linear (Lb NO3)■
10 20 30 40 50
Months since 1/1/2008
60 70
1.60
1.40
1.20
1.00
M
0.80 0
E
0.60
0.40 m
0.20 3
0.00
Figure 23.--Nfonthly flow of groundwater and mass of NO3 delivered to the NRWWTP from the remedial containment systems.
' Sludge -GW Monthly Report January 2014.xls provided by CORPUD
22

�a�e,('esas-ces
The 99% statistically significant rate of increase in flow is 6740 gallons/month or 0.081 million
gallons / year, and the rate of increase in mass of NO3 delivered is approximately 17 lb/year. As
discussed previously the latest modeling shows that the mass of NO3 in groundwater continues to
increase in the capture zone of the containment system because of delayed migration of NO3 from the
vadose zone up -gradient of the capture system. The slight increase in the rate of NO3 delivered to the
plant may be the result of this increase, increases in flow caused by well field efficiency
improvements, or a combination of all of these.
The Field 500 containment system comprises 22 extraction wells as shown on Figure 21. As shown
on Figure 24, the majority of groundwater pumped from this system comes from wells at the south
end of the system along the east boundary of field 500 (Wells RW -1 through RW -8) and from RW -
15. The differences in flow rate are likely the result of variations in permeability of the Saprolite and
Partially Weathered Rock in which the wells are screened.
25% -
20% -
X
5%
0%
N N N N N N N N N N N N N
Figure 24.-- Fraction of gromulwater withdrawn fi-om each well in the Field 500 containment system.
The average observed NO3 in extraction wells for the Field 500 Containment system as of 12/31/2013
is 22.5 mg/I. Regression tests on the trend line in Figure 25 show a statistically significant slight
decrease in the concentration of NO3 being withdrawn from the Field 500 extraction wells.
Approximately 45% of the groundwater captured but only 15% of the NO3 removed by the
containment system is derived from the wells in the Field 500. This is the result of the lower per well
flow rates and the lower NO3 concentrations present up gradient of the Field 500 wells.
23
■ 2008
■ 2009
n2010-
02011 2010■2011
■ 2012
■ 2013
■ 2014
■ Total
�L ILAkIL
dw LIM
N N N N N N N N N N N N N
Figure 24.-- Fraction of gromulwater withdrawn fi-om each well in the Field 500 containment system.
The average observed NO3 in extraction wells for the Field 500 Containment system as of 12/31/2013
is 22.5 mg/I. Regression tests on the trend line in Figure 25 show a statistically significant slight
decrease in the concentration of NO3 being withdrawn from the Field 500 extraction wells.
Approximately 45% of the groundwater captured but only 15% of the NO3 removed by the
containment system is derived from the wells in the Field 500. This is the result of the lower per well
flow rates and the lower NO3 concentrations present up gradient of the Field 500 wells.
23

60
50
40
E 30
0
20
10
0
'We,Pk6atrces
Field 500 Extraction and Monitoring Wells
0 1 2 Years sind 1/1/2008 4 5 6
Figurc 25.—Time trend in NO3 in Field 500 extraction wells and concentrations in monitoring wells in or down gradient of
field.
The Field 50 containment system comprises 7 extraction wells as shown on Figure 22. As shown on
Figure 26, the majority of groundwater pumped from this system comes from 2 wells: RW -25 at the
south end and RW -29 at the north end of the system. The differences in flow rate are likely the result
of variations in permeability of the Saprolite and Partially Weathered Rock in which the wells are
screened.
50%
45%
40% -
35%
m 20%
X10%-
5%
0%
• Extraction Wells RW -1 through RW -22
trm
,
■
■
t
■ Field 500 Monitoring Wells
•
•
•
•
•
■
• —
00
;■
°
■ 1
1 • 1
••
no
01
� •
00
s
•
0 1 2 Years sind 1/1/2008 4 5 6
Figurc 25.—Time trend in NO3 in Field 500 extraction wells and concentrations in monitoring wells in or down gradient of
field.
The Field 50 containment system comprises 7 extraction wells as shown on Figure 22. As shown on
Figure 26, the majority of groundwater pumped from this system comes from 2 wells: RW -25 at the
south end and RW -29 at the north end of the system. The differences in flow rate are likely the result
of variations in permeability of the Saprolite and Partially Weathered Rock in which the wells are
screened.
50%
45%
40% -
35%
m 20%
X10%-
5%
0%
RW -23 RW -24 RW -25 RW -26 RW -27 RW -28 RW -29
Figure 26: - Fraction of groundwater -withdrawn from each well in the Field 50 containment system.
The average observed NO3 in extraction wells for the Field 50 Containment system as of 12/31/2013
is 48 mg/l. Regression tests on the trend line in Figure 27 shows that to date there has been no
statistically significant change in these concentrations at the 99% significance level. Approximately
55% of the groundwater captured and 85% of the NO3 removed by the containment system is derived
24
trm
,
■
■
t
RW -23 RW -24 RW -25 RW -26 RW -27 RW -28 RW -29
Figure 26: - Fraction of groundwater -withdrawn from each well in the Field 50 containment system.
The average observed NO3 in extraction wells for the Field 50 Containment system as of 12/31/2013
is 48 mg/l. Regression tests on the trend line in Figure 27 shows that to date there has been no
statistically significant change in these concentrations at the 99% significance level. Approximately
55% of the groundwater captured and 85% of the NO3 removed by the containment system is derived
24

1WePescrr6e5
from the wells in the Field 50. This is the result of the higher per well flow rate and the higher NO3
concentrations present up gradient of the Field 50 wells.
100
90
80
70
60
E 50
o 40
Z
30
Fla
10
Field 50 Extraction and Monitoring Wells
Years Since 1/1/2008
Figure 27.—'Time trend in n03 in Field 50 extraction wells and concentrations in monitoring wells in or down gradient of field.
2.1 Effectiveness of Groundwater Capture by the Active Containment System
The effectiveness of the capture of groundwater containing NO3 from the Containment System was
evaluated by assessing the capture zones generated with the latest version of the groundwater flow
and transport model using the actual pumping rates shown in Table 1. The capture zones for Fields
50 and 500 are shown in Figure 22.
Based upon where these zones cross the down -gradient (northern and eastern) boundaries of Field
500, essentially 100% of the groundwater emanating from Field 500 is captured and the system has
been 100% effective in meeting the objectives of the containment system for that field.
Based upon where these zones cross the down -gradient (eastern) boundary of Field 50, approximately
50% of the groundwater emanating from Field 50 is captured. Complete capture by the Field 50
wells would require the installation and operation of wells along the areas where the capture zones do
not cross, or increasing the pumping rates of wells on either side of the areas of non -capture. If the
pumping rates of the existing wells cannot be sufficiently increased, approximately 5 additional wells
would be required
The updated model was also used to generate likely NO3 future concentrations at locations of
monitoring wells that are down- gradient from the compliance boundaries of Fields 500 and 50 with
the remedial system in continuous operation if the system had not been turned on. These locations
are shown on Figure 22. Figures 28 and 29 show this comparison and demonstrate that the system
is effective in capturing NO3 in groundwater that otherwise would continue to cause concentrations to
increase more (MW -117) and that the time required for 2L compliance would be longer (MW -203).
25
♦ Extraction Wells
■ Monitoring Wells
—
# #
—Linear (Extraction Wells)
#
IN
40 V
i
_ # #
$
49
# #
$
Years Since 1/1/2008
Figure 27.—'Time trend in n03 in Field 50 extraction wells and concentrations in monitoring wells in or down gradient of field.
2.1 Effectiveness of Groundwater Capture by the Active Containment System
The effectiveness of the capture of groundwater containing NO3 from the Containment System was
evaluated by assessing the capture zones generated with the latest version of the groundwater flow
and transport model using the actual pumping rates shown in Table 1. The capture zones for Fields
50 and 500 are shown in Figure 22.
Based upon where these zones cross the down -gradient (northern and eastern) boundaries of Field
500, essentially 100% of the groundwater emanating from Field 500 is captured and the system has
been 100% effective in meeting the objectives of the containment system for that field.
Based upon where these zones cross the down -gradient (eastern) boundary of Field 50, approximately
50% of the groundwater emanating from Field 50 is captured. Complete capture by the Field 50
wells would require the installation and operation of wells along the areas where the capture zones do
not cross, or increasing the pumping rates of wells on either side of the areas of non -capture. If the
pumping rates of the existing wells cannot be sufficiently increased, approximately 5 additional wells
would be required
The updated model was also used to generate likely NO3 future concentrations at locations of
monitoring wells that are down- gradient from the compliance boundaries of Fields 500 and 50 with
the remedial system in continuous operation if the system had not been turned on. These locations
are shown on Figure 22. Figures 28 and 29 show this comparison and demonstrate that the system
is effective in capturing NO3 in groundwater that otherwise would continue to cause concentrations to
increase more (MW -117) and that the time required for 2L compliance would be longer (MW -203).
25

30
25
20
E
M5
O
2
10
5
0
Jan -00
1�lzle Mesas-ce3
Dec -09 Jan -20 Dec -29 Jan -40 Dec -49 Jan -60 Dec -69
Figure 28.-- NO3 concentrations in monitoring well NIR' -117 under NINA, pumping„ and inactivation of pumping in 2015.
30
25
20
E 5
O
z
10
5
0
Jan -00 Dec -09 Jan -20 Dec -29 Jan -40 Dec -49 Jan -60
Figure 29.-- NO3 concentrations in monitoring well NAV -203 under NINA, pumping, and inactivation of pumping in 201.5.
MW -117
PWR
PWR
--- PWR No Pumping
PWR No PUmping
17
j I
U. \—\
i•• -Is
I� I \I
\%
1
a I
1 I
i
/
/
/
I
/
/
Dec -09 Jan -20 Dec -29 Jan -40 Dec -49 Jan -60 Dec -69
Figure 28.-- NO3 concentrations in monitoring well NIR' -117 under NINA, pumping„ and inactivation of pumping in 2015.
30
25
20
E 5
O
z
10
5
0
Jan -00 Dec -09 Jan -20 Dec -29 Jan -40 Dec -49 Jan -60
Figure 29.-- NO3 concentrations in monitoring well NAV -203 under NINA, pumping, and inactivation of pumping in 201.5.
Dec -69
M
MW -203
PWR
PWR No PUmping
17
1 I
Dec -69
M

J�aje &Wce5
2.2 Evaluation of Alternatives to the Active Containment System
Because the Active Containment System complies with the 2L rules no assessment of additional
alternatives appears to be necessary.
27

��'e l'ez�xces
3 Evaluation of Monitored Natural Attenuation
Monitored Natural Attenuation (MNA) is the remedial activity for the remainder of the Site that is
not affected by the Groundwater Containment System. It is implemented by triennial sampling of
the73 monitoring stations shown in Figure 1. This evaluation only included wells for which sampling
and analysis data was reported for 2013 (16 Compliance Monitoring Wells and 43 additional
monitoring wells located throughout the site and 12 surface water stations that are down gradient of
NRW WTP fields). The evaluation was performed by assessing statistically significant linear trends
over time since 2003 when biosolids applications ceased. Table 3 summarizes the trend directions
and magnitudes for each type of MNA station and for all stations. Measured trends are declining or
constant in 84% of the MNA stations.
Compliance Monitoring Wells Other Monitoring Wells
Rate of
[NO3]
Rate of [NO3] Change,
% of
Change,
% of
mg/I/year
Number
Total
mg/I/year
Number
Total
< 0.0
Count
Count
Trend
9
53%
Trend
19
44%
<
0.0
Model
2
12%
Model
13
30%
Trend
-3.38
Average
Trend
-3.39
Average
Model
-1.30
Model
-2.09
Trend
1
6%
= 0.0
Count
Trend
8
19%
0.0
Count
Model
1
6%
Model
1
2%
Trend
7
41%
> 0.0
Count
Trend
16
37%
Count
>
Model
14
82%
Model
29
67%
0.0
Trend
1.83
Average
Trend
3.19
Average
Model
1.86
Model
1.64
Total Stations
17
Total Stations
43
Surface Water Stations All MNA Stations
Rate of [NO3] Change,
% of
% of
mg/I/year
Number
Total
Rate of [NO3] Change, mg/I/year
Number
Total
Trend
9
75%
Trend
37
51%
Count
Count
<
Model
4
33%
Model
19
26%
< 0.0
Trend
-2.26
Trend
-3.20
0.0
Average
Average
Model
-0.91
Model
-1.56
=
Trend
2
17%
Trend
11
15%
Count
= 0.0
Count
Model
1
8%
Model
3
4%
0.0
Trend
1
8%
Trend
24
33%
Count
Count
Model
7
58%
Model
50
69%
>
> 0.0
Trend
0.42
Trend
2.43
0.0
Average
Average
Model
0.51
Model
1.64
Total Stations
12
Total Stations
72
Table 3.-- Cum pa risoa of Irend in obscr%cd and modeled NO3 at MALA Stations.
28

��le l�e'es�ces
NO3 time vs. concentration plots for all the compliance wells are included in Attachment 3. As
shown in Table 3, approximately the same numbers of compliance wells show increasing and
decreasing trends based on observed values and the rate of decreases is approximately twice as large
as the rate of increase.
Although the monitoring wells interior to the Site are not used to assess 2L compliance, they are
included in this analysis as a general indicator of the effectiveness of MNA following the cessation of
biosolids application in 2003. As shown in Table 3, approximately the same numbers of these
interior monitoring wells show increasing and decreasing trends based on observed values. The rate
of decrease is approximately twice as large as the magnitude of the increasing trends. The plots for
all the interior wells are included in Attachment 4 to this report.
We conclude based on analysis of observed NO3 concentrations since the cessation of biosolids
application in 2003 that MNA is reducing concentrations at the compliance boundary and at
approximately one half of the monitoring locations interior to that boundary. Changes in
concentrations are consistent with the modeled delayed movement of NO3 in groundwater in the
vadose zone as illustrated in Figure 4.
3.1 Evaluation of Alternatives to NINA
Additional remedial measures were evaluated for their potential to enhance the reduction of NO3
concentrations up gradient of the compliance boundary and consequently reduce the time required to
assure no additional migration past the compliance boundary in excess of the 2L standards.
Methodologies that have been used at other sites with NO3 in groundwater include Enhanced in-situ
Biodenitrification, Enhanced Flushing via over irrigation, and Phytoremediation.
3.1.1 Enhanced in-situ Biodenitrification (EISBD)
These measures would include the in-situ injection of compounds such as organic carbon electron
donors such as methanol or acetic acid, or inorganic electron donors such as hydrogen or reduced
sulfur. For reduction to occur the dissolved oxygen content of the in-situ water containing the NO3
must be approximately 0.1 mg/l or less The EISBD compounds enhance the biological de-
nitrification which produces nitrogen gas which would then be removed by gas phase migration to the
land surface through the vadose zone 9.
The application of these technologies has been partially successful in remediating plumes of NO3 in
permeable sand and gravel aquifers. However, to be effective, it requires the ability to effectively
place the amendment in contact with the groundwater zones that contain the NO3 to be reduced. For
the fine-grained Saprolite and PWR materials that underlie in Fields 50 and 500, this would require
placing injection wells in at least as many locations as there are extraction wells.
Application of de -nitrification technologies to the residual NO3 in groundwater present in the vadose
zone beneath fields up gradient from the compliance boundary zone would require the ability to place
any amendments in effective contact with this water. Because the majority of such water in the
vadose zone is held by capillary tension, such contact could only be implemented by continuously
applying the amendment at the land surface. Establishment of effective contact of the amendment
with the groundwater in the vadose zone under conditions of natural recharge would require at least
' http://www.swhvdro.arizona.edu/archive/V8 N4/feature6.pddf
'Interstate Technology and Regulatory Cooperation Work Group, 2000 Emerging Technologies for Enhanced In Situ
Biodenitrification (EISBD) of Nitrate -Contaminated Ground Water.
29

We Ak5arce5
as long as the time required for the NO3 to be reduced by continued downward migration without the
addition of any amendment.
The number of wells to inject de -nitrifying amendments would be equal to for greater than he number
of extraction wells along the compliance boundary which were determined in the Variance to not be a
cost effective cost remedy to MNA. EISBD would also incur the costs of the injected compounds,
systems to supply them to the wells, and to monitor its effectiveness. Therefore for the same reasons
given in the Variance, EISBD would not be cost effective and would result in unreasonable economic
hardship to the City. The cost of land applying denitrifying amendments to the land surface, if
feasible, would add further costs to this alternative.
3.1.2 Enhanced Flushing
It is evident from the field sampling program discussed in Section 1.3.1 that irrigation of fields has
the potential to enhance the flushing of groundwater containing NO3 from the vadose zone. The
effectiveness of such flushing would require irrigating in excess of plant uptake and moisture holding
capacity of the root zone.
Enhanced flushing by over -irrigation could also increase the effectiveness of contact of any de-
nitrifying amendment with water in the vadose zone.
However, limits on irrigation rates in the Permit to minimize formation of shallow seasonal high
water tables, and downward migration of NO3 would seem to preclude the use of enhanced flushing
by increasing irritation rates in fields up gradient of the compliance boundary.
3.1.3 Phytoremediation
Phytoremediation is the process by which excess NO3 in groundwater in the vadose and saturated
zones is removed by vegetation.
The potential limits to the effectiveness of phytoremediation include the following:
• High concentrations of nitrate and/or ammonia which may result in plant toxicity, either
overall or at certain developmental stages of the plant;
• Depth of contamination which may exceed the rooting depth of plants;
• Heavy, tight and/ or poorly drained soils which may limit rooting depth; and
• The length of time it takes plantings to mature sufficiently to become effective at significant
nitrogen removal.
Application of phytoremediation with terrestrial plants is limited to the vadose zone and the top
surface
of the saturated zone. Roots of these plants do not grow deeply into the saturated zone even when it
is very shallow. Plants used for nitrate phytoremediation include: phreatophyte trees such as poplar
and willow; grasses such as rye, Bermuda, sorghum, and fescue); and legumes such as clover, and
Alfalfa. Root depths of the above tree species are essentially never over 10 to 13 feet, and can be
much shallower depending on soil conditions. (Crow 2005). Mature root systems of rye and
sorghum can extend to around 5 feet in ideal conditions and while alfalfa and clover taproots can
extend to over 10 feet, bur are rarely over 5 feet] 0.
1D littn://eroundwaternitrate.ucdavis.edu/files/139112xdf
30

,Paje &WC, -s
Based upon measurements in observation wells and modeling the depth to the watertable below most
fields up gradient of the compliance boundary is generally greater than 10 to 15 feet during the
growing season. Therefore using phytoremediation at the down gradient boundaries of fields to
enhance MNA does not appear to be feasible.
31

�a�le,f'esarces
4 Evaluation of Subsurface Flow Wetlands
The following description of the Subsurface Flow Wetlands is adapted from the 2013 Annual
Monitoring Report. These wetlands were installed by CORPUD as part of the agreement with the
Neuse River Foundation as part of the implementation of the Variance.
4.1 Constructed Wetland Construction, Operation, and Sampling
Constructed wetlands have been installed at three locations (A, C, and E) on three drainages that
receive surface runoff and groundwater discharge from fields to which biosolids were applied during
the 1979 to 2002 at the locations shown on Figure 1. The systems were constructed during 2010 and
comprise constructed inlet and outlet structures to create wetland conditions. Planting of wetland
species in the areas between the inlet and outlet structures was completed in October 2010. Wetland
vegetation became well established during the first growing season in 2011.
The wetlands began receiving flow from upstream areas in the spring of 2011. Fine sediment
accumulation around the intake structures reduced the inflow to all three wetlands. Repairs to the
intake structures at all three wetlands were modified to reduce sedimentation so as to restore design
inflows. Modifications to the overflow structure of the outflow dam on Wetland E were also required
for that wetland to function properly. All repairs were completed early in 2013. The water levels in
the outflow boxes required to compute outflow rates are currently measured using staff gages. These
gages replaced pressure transducers and data loggers in February 2013 to simplify and improve on
the reliability of readings required to measure outflows.
Samples for analysis of NO3 concentrations in the inflow and outflow from each wetland are
collected bi-monthly when flow measurements are made. During the second sampling each month, a
sample is also collected at a location downstream of the wetland outfalls.
4.2 Evaluation of Removal Efficiencies of Wetlands
Sample analyses for NO3 from October 5, 2011 to the present were reviewed to assess the
performance of the wetlands. Because the necessary repairs to the wetlands were not completed until
February 2013, this evaluation only uses the bi-monthly sampling and flow measurements from that
date to the present. Because the purpose of the wetlands is to remove the mass of NO3, this analysis
has used the measured outflow and influent and effluent concentrations to compute the mass of NO3
inflow to and outflow from each wetland. The mass was computed using the following equation:
Mass of NO3, lb/day = [NO31 mg/( x outflow, gallons / day * 8.34 / 106 gallons / Mgal. The 8.34 is a
units conversion constant to change mg/1 to lb/Mgal.
Table 4 shows the outflow rates, NO3 concentrations in the inflow and outflow, and the computed
mass of NO3 in the inflow and outflow for each wetland.
Statistical analyses using one -factor analysis of variance was performed to assess the probabilities
that the constructed wetlands have removed a significant mass of NO3 since they became fully
operational in February of 2013. Analyses were performed comparing all the analyses since February
2013 and for the period from July 2013 on. The second period was used to reflect the likely full
establishment and functioning of the wetland vegetation in removing NO3. Table 5 shows the
resultant probabilities.
32

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eaje>{'esam-5
Table S.—IN lass removal of NO3 by the wetlands since becoming fully operational and average rate of removal since.hdy 2013.
Figures 30 through 32 show the time trends in mass of NO3 in the inflow and outflow from the
wetlands. The changes in mass in the inflow are the result of continued leaching from the vadose
zone beneath up -gradient fields as documented in the report assessing resumption of biosolids
applications 5.
Wetland A
4.50
4.00
3.50
m
3.00
0 2.50
0 2.00
Z
6 1.50
m
2 1.00
0.50
Probability of significant
mass removal
Average annual mass
removed
Efficiency of
removal
Feb 2013 to July 2013 to
Mar 2014 Mar 2014
Ib/year
% of
Inflow
(Probability x
% reduction)
Wetland A
89% 91%
259
60%
55%
Wetland C
52% 99%
274
47%
47%
Wetland E
1% 100%
35
76%
76%
Table S.—IN lass removal of NO3 by the wetlands since becoming fully operational and average rate of removal since.hdy 2013.
Figures 30 through 32 show the time trends in mass of NO3 in the inflow and outflow from the
wetlands. The changes in mass in the inflow are the result of continued leaching from the vadose
zone beneath up -gradient fields as documented in the report assessing resumption of biosolids
applications 5.
Wetland A
4.50
4.00
3.50
m
3.00
0 2.50
0 2.00
Z
6 1.50
m
2 1.00
0.50
0.00
12/18 1/17 2/16 3/18 4/18 5/18 6/17 7/17 8/17 9/16 10/16 11/15 12/16 1/15 2/14 3/16 4/16
Figure 311: -Comparison of NO3 mass in inflow and outtlo)v for Welland A.
:v
*Ma ss in Ib/day
■ Mass Out Ib/day
■
■
_
♦
or—
■
■
0.00
12/18 1/17 2/16 3/18 4/18 5/18 6/17 7/17 8/17 9/16 10/16 11/15 12/16 1/15 2/14 3/16 4/16
Figure 311: -Comparison of NO3 mass in inflow and outtlo)v for Welland A.
:v

7.00
6.00
R 5.00
9
a
0 4.00
M
Z 3.00
0
N
^2 2.00
1.00
Wetland C
■
♦ Mass in Ib/day
■ Mass Out Ib/day
■
im
♦
■
eaje Re5axzes
12/18 1/17 2/16 3/18 4/18 5/18 6/17 7/17 8/17 9/16 10/16 11/15 12/16 1/15 2/14 3/16 4/16
Figure 31.— Comparison of NO3 mass in inflow and outflow for Wetland C.
Wetland E
rMIRIENENMENIIIN■
■■■iii■■■■1.---■■■■
Figure 32: - Comparison of NO3 mass in inflow and outnow for Wetland G.
35

wale 91---ar .5
We conclude that the fully functioning wetlands are effective at removing NO3 from the surface
water. However the wetlands to date do not remove 100% of the NO3 from the surface water as
shown in Table 7. The amount of mass removed per year is only a small fraction of the mass entering
all drainages from the fields and eventually entering the Neuse River if all loading to the fields is at
the 2L standard of 10 mg/I as shown in Figure 7.
5 Evaluation of Off -Site Riparian Buffer Restoration
In agreement with the Neuse River Foundation, as part of the Variance, CORPUD purchased and
completed buffer restoration of the Butlers Branch site in Craven County, North Carolina in 2010.
The site comprises approximately 54 acres of headwater buffer habitat and includes three main
tributary systems that drain directly to the Neuse River. Restoration Systems, LLC completed the
restoration for CORPUD. Restoration activities comprised the following:
• Removal of nonpoint sources of pollution associated with agricultural practices;
• Reduction of sedimentation and siltation within on-site and downstream receiving waters;
• Promotion of floodwater attenuation; and
• Providing terrestrial wildlife habitat.
The restoration has resulted in providing 4,091 Ib of nitrogen offset per year, or a reduction of
122,742 pounds of reduced N loading to the Neuse River over 30 Years .
Because this restoration is complete and functioning, further evaluation of this remedial activity is not
necessary.
" 2013 Annual Report, page 2-3.
36

ease Pesat ce5
6 Conclusions
This review has assessed the following remedial activities required by the Variance: Groundwater
Containment System; Monitored Natural Attenuation; Constructed Subsurface Flow Wetlands,
and Off -Site Riparian Buffer Restoration.
6.1 Groundwater Modeling Conclusions
This review has reached the following conclusions regarding updates to the groundwater flow and
transport models since the model constructed for the SSA that was used to support the Variance:
The hydrogeologic modeling of the Site was significantly modified to account for the
residual NO3 in groundwater in the vadose zone that had not been assumed to be
present in the SSA model;
As updated, the groundwater flow and transport model for the Site shows adequate
agreement with the rates of changes over time and the concentrations of NO3 in the
water withdrawn from the containment system and therefore can be used as an
effective tool to extrapolate future concentrations and mass removal rates; and
However, as discussed above, the model is conservative in that it consistently over
predicts groundwater concentrations in groundwater and surface water relative to
observed conditions.
6.2 Groundwater Containment System Conclusions
This review has reached the following conclusions for the Groundwater Containment System:
• The active groundwater containment system has operated at essentially the design
capacity for all the extraction wells since system startup in January 2008;
• The containment system for Field 500 is capturing essentially 100% of up -gradient
groundwater and preventing the further down -gradient migration of NO3;
• The containment system for Field 50 is capturing approximately 50% of up -gradient
groundwater containing and reducing the further down -gradient migration;
• Approximately 55% of the groundwater captured from the containment system is
derived from the 7 wells down gradient of Field 50 and 45% from the 22 wells down
gradient of Field 500; and
• The groundwater containment system has removed 75 million gallons of groundwater
and 18,000 Ib. of NO3 from system startup in January 2008 through January 2014.
6.3 Monitored Natural Attenuation Conclusions
This review has reached the following conclusions for the Monitored Natural Attenuation (NINA):
• The majority of monitoring stations show either declining or non-changing concentrations
over the 2008 through 2013 period. The surface water stations that monitor drainage from
multiple fields also show a significant decline in NO3 concentrations for this period. These
stations integrate the effects of natural attenuation over large areas of the Site;
37

• Although the directions of the modeled trends do not necessarily agree well with the observed
trends, the magnitude of the modeled values generally agree with the observed values as of
the end of 2013;
Because more observed than modeled trends show decreasing NO3 concentrations over time,
the model predicts longer times to achieve compliance that is indicated by the observed data;
and
The Variance concluded that NINA was an acceptable approach to corrective action for that
portion of the Site not affected by the groundwater containment system because available
technologies to actively remediate the remainder of the Site would be cost prohibitive and
result in significant economic hardship to the City. Our review of the literature and our
experience show that no new cost effective technologies have been developed that would alter
this conclusion.
6.4 Subsurface Wetlands Conclusions
The fully functioning wetlands are effective at removing NO3 from the surface water. However the
amount of mass removed per year is only a small fraction of the mass entering all drainages from the
fields and eventually entering the Neuse River if all loading to the fields is at the 2L standard of 10
mg/1.
The loading to the Neuse from continued discharge of groundwater surface water containing NO3 at
concentrations greater than the NC 2L standard of 10 mg/l has not resulted and will not result in
exceeding the NC 2B standard for NO3. The N loading to the Neuse from this source is accounted
for in the permitted discharge from the NRWWTP.
6.5 Off -Site Riparian Buffer Restoration Conclusions
The off-site restoration at the Butlers Branch site has resulted in providing 4,091 lb of nitrogen offset
per year, or a reduction of 122,742 pounds of reduced N loading to the Neuse River over 30 Years.
Because this restoration is complete and functioning additional evaluation of this remedial activity is
not necessary.
38

Attachment L-2014 Annual Monitoring Report
39

�� ar//r `awn//•�rt�
January 28, 2014
Mr. Rick 8oiich
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Raleigh Regional Office Aquifer Protection Section
1628 Mail Service Center
Raleigh, NC 27699-1628
Re: Annual Monitoring Report, Neuse River Wastewater Treatment Plant
City of Raleigh, Non -Discharge Permit #WQ0001730
Dear Rick:
In accordance with the final decision on January 15, 2010 by the Environmental Management
Commission of the revised CAP and related request for variance from groundwater regulations 15A
NCAC 2L.0107(K)3(A) and 15A NCAC 2L.0106(J) we are forwarding to you for review the annual site
monitoring report. The City has been actively monitoring groundwater and surface water quality at the
Site as part of their ongoing investigation.
If you have any further questions or concerns, or require any additional information, please do not
hesitate to contact me at [phone].
Sincerely,
Tim Woo
Division hector
cc: Mr. John Robert Carman, Public Utilities Director
Mr. Robert Massengili, Assistant Public Utilities Director
Mr. Kenneth Waldroup, Assistant Public Utilities Director
Mr. TJ Lynch, Assistant Public Utilities Director
Mr. Steve Levitas, Kilpatrick -Stockton LLP
Mr. Eric Lappala, Eagle Resources
OFFICES • 222 WEST HARGETr STREET • POST OFFICE BOX 590 • RALEIGH, NORTH CAROLINA 27602
RECYCLED PAPER

Prepared by:
City of Raleigh
Public Utilities
Department
Raleigh, NC
January 2014
Annual Monitoring Report
Neuse River Wastewater Treatment Plant,
Raleigh, North Carolina

Annual Monitoring Report
Neuse River Wastewater Treatment Plant,
Raleigh, North Carolina
c9 )c
Prepared By Tim Wood'
/ IGt (on3.✓ rOWCr
Reviewed By (print namelsignature)
Prepared by.
City of Raleigh
Public UOlttles
Department
Raleigh, NO
January 2014

Contents
1.0 Introduction ................... ................................................................................................. 1-1
1.1 Site Description................................................................................................................... 1-1
1.2 Site History .......................................................................................................................... 1-1
2.0 Remediation Activities to Date.....................................................................................2-1
2.1 Status of Remediation Activities.........................................................................................
2-1
2.1.1
Groundwater Containment System ........... ........... ............ ............... ...
... ............ - 2-1
2.1.2
Monitored Natural Attenuation.............................................................................2-1
2.1.3
Subsurface Flow Wetlands..................................................................................2-1
2.1.4
Vadose Zone Monitoring.....................................................................................
2-2
2.1.5
Off -Site Riparian Buffer Restoration....................................................................
2-3
2.2 Monitoring Results: Groundwater and Surface Water Quality ...........................................
2-3
2.2.1
Methods................................................................................................................2-3
2.2.2
March 2013 Sampling Event................................................................................
2-4
2.2.3
July 2013 Sampling Event...................................................................................
2-5
2.2.4
November 2013 Sampling Event.........................................................................
2-5
2.2.5
Private Well Sampling..........................................................................................
2-6
2.2.6
Subsurface Flow Wetlands Monitoring................................................................
2-6
3.0 Summary and Recommendations................................................................................3.1
4.0 References Cited
List of Appendices
Appendix A Approval of Variance Request
..... ...................................................................... 4-1
Appendix B NCDENR Subsurface Wetland Monitoring Modification Letter
Appendix C Butlers Branch Year 4 Monitoring Report
Appendix D Field Data Sheets
Appendix E Laboratory Data
January 204

List of Tables
Table 1 Remediation Well Summary --Groundwater Containment System
Table 2 Well Construction Details
Table 3 Historical Nitrate Analytical Data
Table 4 March 2013 Nitrate Analytical Data
Table 5 July 2013 Nitrate Analytical Data
Table 6 November 2013 Nitrate Analytical Data
Table 7 March 2013 Groundwater Elevation Data
Table 8 July 2013 Groundwater Elevation Data
Table 8 November 2013 Groundwater Elevation Data
i. Table 10 Subsurface Flow Wetlands Monitoring
List of Figures
Figure 1 Site Location Map
Figure 2 Topographic Map
Figure 3 Off -Site Riparian Buffer Restoration, Butlers Branch Site
Figure 4 March, July, & November 2013 Nitrate Analytical Data
Figure 5 March, July, & November 2013 Groundwater Elevation Map
iv
January 2014

List of Acronyms
amsl
above mean sea level
CAP
Corrective Action Plan
CORPUD
City of Raleigh Public Utilities Department
DWQ
Division of Water Quality
mg/L
milligrams per liter
NCAC
North Carolina Administrative Code
NRWWTP
Neuse River Wastewater Treatment Plant
NSW
Nutrient Sensitive Waters
pwr
partially weathered rock
In
January 2014

1-1
1.0 Introduction
City of Raleigh Public Utilities Department (CORPUD) prepared this annual monitoring report to report
the monitoring activities conducted during 2013 to address nitrate contamination in groundwater and
surface water at the biosolids application fields serving the Neuse River Wastewater Treatment Plant
(NRWWTP). The NRWWTP (the Site) is located at 8500 Battle Bridge Road in Raleigh, Wake
County, North Carolina (Figure 1). This annual monitoring report has been prepared to meet the
requirements of the variance from certain 15A NCAC 2L rules Issued by the Environmental
Management Commission to the City of Raleigh on January 15, 2010 (Appendix A). Monitoring
requirements for this CORPUD program are provided in Appendix A,
1.1 Site Description
The NRWWTP consists of approximately 1,466 acres of mostly contiguous farmland owned by
CORPUD and divided into numbered fields. Properties surrounding the Site consist of residential
properties, farmland, and state-owned farmland. The northern and eastern boundaries border a 3.6 -
mile section of the Neuse River. Beddingfield Creek bounds the Site to the south. Topographically,
the Site ranges in elevation from an approximate high of 280 feet above mean sea level (amsl) in
upland areas to an approximate low of 140 feet amsl at the Neuse River (Figure 2). A layout of the
facility, associated blosolids application fields and the current compliance boundary are depicted on
Figure 1.
The Neuse River is classified as a Class C NSW (nutrient sensitive water) from the Falls Lake Dam to
the mouth of Beddingfield Creek. From the mouth of Beddingfield Creek to approximately 0.2 miles
downstream of Johnston County State Road 1700, the Neuse River is classified as Water Supply V
NSW. Beddingfield Creek is classified as Class C NSW from the source to the Neuse River. No
nitrate water quality standard has been established for Class C NSW water. For surface waters
classified as Water Supply V NSW, the state -imposed nitrate water quality standard is 10 milligrams
per liter (mg/L), the drinking water standard.
1.2 Site History
The NRW WiP has been operated since 1976 and biosolids were land -applied at the Site from 1980
through September 2002 under a land application permit (Permit #WQ0001730). During this period,
fields have been added and removed from biosolids application. Fields 1, 2, and 3 were removed
from biosolids application in 1998 and converted Into a police training facility. Fields 100, 101, 102,
200, 201, 500, 501, 502, 503, 511, 512, 513, 522, 523, 524, 600, 601, 602, and 603 were previously
leased for biosolids application. Fields 200,201,500, 501, 502, 503, 511, 512, 513, 601 and 602 have
subsequently been purchased by the City. The remaining fields are owned by CORPUD. The property
containing former leased fields 100, 101, 102, 522, 523, and 524 are currently owned by Waste
Corporation of America. This property has been developed as a construction and demolition debris
landfill.
Groundwater quality monitoring required under the permit revealed exceedances of the NCAC 2L
nitrate groundwater standard in proximity to the compliance boundary of CORPUD owned
January 2614

1-2
biosolids application fields. Land application of biosolids was suspended in September 2002. Since
that time, there has been extensive investigation of the Site to evaluate groundwater quality and to
develop remediation actions (e.g., ENSR, 2002; ENSR, 2003; ENSR, 2005), including those
described in this report.
Modifications to the existing land application permit (Permit #WQ0001730) were approved on
September 4, 2013. These modirications allow for reapplication to select NRW WTP on-site fields as
follows. Fields 5, 6, 7, 8, 9, 10,11, 12, 14, 23, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 36, 43, 44, 45, 46,
47, 48, 62, 63, 70, 71, 73, 501, 511, 519, 520, and 602.
Application resumed on Field 32 in December 2013.
January 2014

2.1
2.0 Remediation Activities to Date
A Comprehensive Site Assessment was completed in December 2002 (ENSR, 2002), followed by a
Supplemental Site Assessment in 2003 (ENSR, 2003). A revised Corrective Action Pian (CAP) was
submitted in November 2005 (ENSR, 2005). DWQ's conditional approval of the CAP was issued to
CORPUD on July 19, 2006 and the City began active remediation in January 2007. On January 15,
2010, the Environmental Management Commission granted the City's request for a variance from the
2L rules, but required extensive groundwater and surface water monitoring as conditions of the
variance. On September 2, 2010, DWQ approved the monitored natural attenuation portion of the
CAP based on the variance.
2.1 Status of Remediation Activities
2.1.1 Groundwater Containment System
Active remediation at the Site includes a groundwater containment system for Fields 50 and 500,
using appropriately spaced extraction wells along the compliance boundaries for these two fields
(Figure 1). The groundwater extraction wells allow for containment of the dissolved nitrate plume.
There are 7 extraction wells along the compliance boundary for field 50 and 22 wells along the
compliance boundary for field 500 (Figure 1). Water produced from the extraction wells is collected at
a pump station located along Old Baucom Road and discharged to the head works of the NRWWTP
for treatment by the facility. System operations began in January 2007, and the system has been
running continuously since that time.
Monthly pumping data and triennial water quality sampling data were collected for the extraction well
network, which Includes wells RW -1 through RW -29 (Table 1). Pumping data indicate variable
monthly pumping averages across the well network, with an average pumping rate of 1,294,345
gallons per month of groundwater produced by the extraction wells. In total, the extraction well
network produced 15,532,150 gallons of groundwater during calendar year 2013 (Table 1).
Monthly nitrate concentration data were collected at the pump station, which Incorporates all water
produced from the extraction well network. Average monthly nitrate concentration for the overall flow
volumes, was 29.06 mgtL for calendar year 2013 (Table 1), which is comparable to the average of
29.65 and 28.49 mglL for calendar years 2011 and 2012 respectively. For calendar year 2013, the
average concentration and total volume produced from the well network corresponds to a removal of
3759.89 pounds of nitrogen from groundwater as a result of the groundwater containment system's
groundwater extraction, similar to the 3,180 pounds removed in 2012.
2.1.2 Monitored Natural Attenuation
Long-term monitoring of natural attenuation of groundwater concentrations is being performed for the
remaining areas on the Site. Groundwater and surface water quality data for the 3 monitoring events
is discussed in Section 2.2, below.
2.1.3 Subsurface Flow Wetlands
Surface water is being remediated through the use of subsurface flow constructed wetlands along
three stream segments at the Site (Figure 1). These systems were constructed during 2010, with
wetland plantings completed in October 2010. During spring 2011, these constructed wetlands
JanMY2014

2-2
came on-line and started receiving flow. Fine sediment around the intake structures reduced flow at
all three wetlands. Intake structures at Wetland A and Wetland C were modified to reduce and
account for sedimentation and allow for design flows. Flow through these wetlands is now occurring
as designed. Wetland E intake was also modified; however, it was determined that repairs to the dam
overflow were necessary for this intake to function properly. These repairs were completed early in
2013. Vegetation in all three wetlands became well established during the first growing season in
2011.
Additionally, the designed method of flow measurement using a Diver data logger did not provide
sufficient data to calculate the nitrate removal efficiency of the wetlands. The data logger was overly
sensitive and unreliable in providing accurate readings. To remedy this Issue, staff gages were
placed inside the outlet box at each wetland in February 2013 to simplify the readings and improve
flow measurement accuracy.
In addition to the installation of the staff gages, NCDENR approved bf-monthly flow measurements to
be taken concurrently with water quality samples in order to improve the accuracy of data collected
from the wetlands (Appendix B). Inflow and outflow samples are taken twice a month when flow
measurements are read. During the second sampling event of each month, a sample is also collected
downstream from the wetland outfall in order to monitor nitrate levels in the stream that is receiving
the outfall. This sampling adheres to the Operation and Maintenance Plan that was developed for the
subsurface flow wetlands when they were constructed.
Wetland C began experiencing issues with flooding in fall 2013 and has been taken off-line in order to
try and determine what Is causing the issue and what corrective measures need to betaken. Even
though the wetland has been taken off-line and is no longer receiving flow from the retention pond,
water continues to Inundate the wetland and samples are still being collected bi-monthly in order to
fulfill monitoring requirements.
Sample results from bl-monthly monitoring of the wetlands are discussed in detail in Section 2.2.6.
Wetlands A and C are showing some reduction of nitrates. Concentrations at Wetland E are currently
low enough that no reduction has been noted. Prior to the modification of the Wetland E intake/dam,
Improper functionality was a contributing factor to the nitrate removal process. Nitrate concentrations
were typically lower on the upstream side of the wetland and higher at the outflow. Since the
modiflcations have been completed, nitrate concentrations are beginning to return to what would be
expected (higher at the intake and lower at the outflow).
It should be noted that the denitrification process is dependent upon the buildup of organic material in
the subsurface rock matrix in the wetlands, and it will likely take several years for these wetlands to
become fully functional.
An Operation and Maintenance Plan was developed for the subsurface flow wetlands and was
Implemented in 2012.
2.1.4 Vadose Zone Monitoring
Vadose zone monitoring devices were Installed in Fields 8, 33, and 45 on November 22 and 23, 2013.
The gages will be sampled monthly in order to comply with WQ Permit #0001730 requirements that
allow for land application of Class B residuals.
Jwuary=4

2-3
2.1.5 Offsite Riparian Buffer Restoration
During 2010, CORPUD completed the purchase and off-site riparian buffer restoration for the Butlers
Branch site in Craven County, North Carolina. Also during 2010, Restoration Systems, LLC
completed riparian buffer restoration at the site, which consists of approximately 54 acres of
headwater buffer habitat. The site includes three main tributary systems that drain directly to the
Neuse River. Prior to construction work, the site was characterized by agricultural fields and disturbed
forest, and site streams were regularly dredged and cleared of vegetation. Land use practices
including the maintenance and removal of vegetation, regular plowing, and use of agricultural
chemicals resulted In degraded water quality in the Neuse River tributary streams (Restoration
Systems, LLC, and Axiom Environmental, Inc., 2013).
The goals and objectives of the restoration project focused on improving local water quality, improving
bank stability, supporting in -stream habitat (through the contribution of large woody debris), and
maintaining wildlife passage corridors (Restoration Systems, LLC and Axiom Environmental, Inc.,
2013). The goals for this restoration program were accomplished by Restoration Systems by the
following actions:
• Removing nonpoint sources of pollution association with agricultural production;
• Reducing sedimentation/siltation within on-site and downstream receiving waters;
• Promoting floodwater attenuation, and
• Providing terrestrial wildlife habitat.
Project construction was performed in late winter/early, spring 2010. Restoration work resulted in
providing 4,091 pounds of nitrogen offset per year, which equates to a reduction of greater than
122,742 pounds of nitrogen offsets over 30 years for the City of Raleigh (Restoration Systems, 2013).
Monitoring of the planted buffers was performed in October 2013 and showed an average of 840
stems per acre, which exceeds the vegetative success criteria (in Year 5) of 320 planted stems per
acre. A copy of the Restoration Systems, LLC Year 4 monitoring report is included as Appendix C.
2.2 Monitoring Results: Groundwater and Surface Water Quality
2.2.1 Methods
Three sampling events were conducted in 2013, in March, July, and November. A total of 73 wells
were sampled during each event, 58 shallow and 15 deep. Wells that are considered deep wells are
those where the well terminates in bedrock or partially weathered rock (pwr). These wells are MW -
1011), MW -104R, MW -105D, MW -111D, MW -113D, MW -121R, MW -122D, MW -123D, MW-124DR,
MW -125D, MW -126D, MW -204, MW -205, MW -206, and MW -207. Additionally, 24 surface water
samples were collected for laboratory analysis of nitrate. The monitoring wells are grouped as
compliance wells and active monitoring wells. Prior to purging and sampling, the depth to water was
measured in each well. Purging was accomplished, ideally, by removing a minimum of three well
volumes or until the well was dry. Sampling was conducted within 24 hours of the purging and the
sample was placed In laboratory -supplied containers. Surface water samples were collected with
clean sampling devices at the designated surface water sample location within perennial and
Intermittent streams and wetlands. After collection, the samples were transported to the NRW WTP
laboratory under standard chain -of -custody procedures.
Field sample collection data sheets are included as Appendix D. Laboratory data are included as
Appendix E.
January 2014

2-4
Per the variance approval documented in Appendix A, new monitoring wells were installed in 2010
and several existing monitoring wells were abandoned and replaced with new and/or deeper
monitoring wells. Well names for the new and replaced wells were assigned based on the protocol
defined here. New wells were assigned names following the latest numerical scheme (MW -200
series, thus the newest wells were MW -204 and up). Replacement wells were named based on the
original well name (e.g., MW-42AR is the replacement well for MW -42A). Well construction details,
Including installation date, total depth, well diameter, casing, screen length, and depth of the screened
interval are provided in Table 2. Historical groundwater and surface water analytical data for the
monitoring wells and surface water monitoring stations are provided in Table 3.
A meaningful nitrate isoconcentration map for each sampling event cannot be generated for the entire
Site because groundwater concentrations vary within individual fields and along the compliance
boundary. Nitrate -contaminated groundwater derived from the fields is not predicted to migrate
across major streams such as Beddingfield Creek. Historical groundwater quality data support the
conclusion that the streams are receiving groundwater discharge and that there is insignificant
underflow, if any, across the streams (ENSR, 2005).
2.2.2 March 2013 Sampling Event
Groundwater and surface water analytical data for the monitoring wells and surface water monitoring
stations for the March 2013 sampling event are provided In Table 4. Groundwater elevation data for
the sampling event are provided in Table 7. A map of nitrate as nitrogen concentrations for the March
2013 sampling event is presented in Figure 4. A groundwater elevation map for the March 2013
sampling event is presented in Figure 5.
For the March 2013 event, two of the shallow wells were dry and were not sampled. Forty of the
shallow well samples analyzed indicated concentrations greater than the 2L standard of 10 mg/L
(Figure 4). Of the 40 samples with concentrations greater than 10 mg/L, 9 contained nitrate
concentrations greater than 50 mg/L. These concentrations are present across the Site and are
correlative with historical locally high groundwater concentrations (Table 3).
Ten of the 15 groundwater samples collected from the deep monitoring wells contained nitrate
concentrations greater than 10 mg/L. The highest concentration was recorded in MW -101 D (109.9
mg/L), as shown on Figure 4.
A total of 20 surface water locations were sampled during the March 2013 sampling event. Four
locations (SW -7, SW -15, SW -17, and SW -26) were dry. Eight of the 20 samples contained nitrate
concentrations greater than 10 mg/L. Only two locations contained nitrate concentrations greater than
50 mg/L, as shown on Figure 4.
Nitrate concentration data for the monitoring event are consistent with the conceptual understanding
of groundwater and surface water nitrate distribution for the Site based on the last several years of
Investigation. Additionally, the nitrate concentration data are relatively consistent with historical trends
and distributions across the Site.
Depths to groundwater across the Site range from approximately 2 to 46 feet below ground surface.
Measurements collected during the March 2013 event Indicate that groundwater flow Is generally
consistent with topography (Figure 5). Within the Piedmont region, streams and rivers are generally
gaining streams. Based on the historical data and current mapping, groundwater discharges to
surface water throughout most of the Site. The Neuse River is a groundwater discharge feature and,
as such, groundwater flows predominantly toward the river across the Site. The potentiometric
January 2014

2-5
surface map illustrates that three groundwater divides are present in the central and southern portions
of the Site (Figure 5).
2.2.3 July 2013 Sampling Event
Groundwater and surface water analytical data for the monitoring wells and surface water monitoring
stations for the July 2013 sampling event are provided in Table 5. Groundwater elevation data for the
sampling event are provided in Table 8. A map of nitrate as nitrogen concentrations for the July 2013
sampling event is presented in Figure 4. A groundwater elevation map for the July 2013 sampling
event is presented in Figure 5.
For the July 2013 event, forty of the 58 samples analyzed indicated concentrations greater than 10
mg/L (Figure 4). Of the 40 samples with concentrations greater than 10 mg/L, 10 samples contained
nitrate concentrations greater than 50 mg/L. These concentrations are present across the Site and
are correlative with historical groundwater concentration trends (Table 3).
Ten of the 15 groundwater samples collected from the deep monitoring wells contained nitrate
concentrations greater than 10 mg/L (Figure 4). Of those 10 samples, two contained nitrate
concentrations greater than 50 mg/L: MW -1011)(120.94 mg/L) and MW -105D (55.34 mg/L).
A total of 23 surface water samples were collected during the July 2013 sampling event: sample
location SW -15 was dry. Five of the 23 samples analyzed contained nitrate concentrations greater
than 10 mg/L (Figure 4).
Nitrate concentration data for the monitoring event are consistent with the conceptual understanding
of groundwater and surface water nitrate distribution for the Site based on the last several years of
investigation. Additionally, the nitrate concentration data are relatively consistent with historical trends
and distributions across the Site.
Groundwater elevations were collected during the July 2013 sampling event (Table 8). The
groundwater elevation map created using the July 2013 data (Figure 5) is consistent with the
groundwater mapping for the March 2013 sampling event.
22.4 November 2013 Sampling Event
Groundwater and surface water analytical data for the monitoring wells and surface water monitoring
stations for the November 2013 sampling event are provided in Table 6. Groundwater elevation data
for the sampling event are provided in Table 9. A map of nitrate as nitrogen concentrations for the
November 2013 sampling event is presented in Figure 4. A groundwater elevation map for the
November 2013 sampling event is presented in Figure 5.
For the November 2013 event, one of the shallow wells was dry and not sampled. Forty-one of the 57
shallow/saprofite well samples analyzed indicated concentrations greater than 10 mg/L (Figure 4). Of
the 41 samples with concentrations greater than 10 mg/L, 11 samples contained nitrate
concentrations greater than 50 mg/L. These concentrations are present across the Site and correlate
with historical locally high groundwater concentrations (Table 3).
Ten of the 15 groundwater samples collected from the deep monitoring wells contained nitrate
concentrations greater than 10 mg/L (Figure 4), Of those 10 samples, MW -101 D (110.48 mg/L) and
MW -105D (61.76 mg/L) contained a nitrate concentration greater than 50 mg/L.
Jwary 2014

2-6
A total of 19 surface water samples were collected during the November 2013 sampling event:
sample locations SW -7, SWA 5, SWA 7, SW -28, and SW -27 were dry. Eight of the 19 samples
analyzed contained nitrate concentrations greater than 10 mg/L (Figure 4). Three samples contained
concentrations greater than 50 mg/L.
Nitrate concentration data for the monitoring event are consistent with the conceptual understanding
of groundwater and surface water nitrate distribution for the Site based on the last several years of
investigation. Additionally, the nitrate concentration data are consistent with historical trends and
distributions across the Site.
Groundwater elevations were collected during the November 2013 sampling event (Table 9). The
groundwater elevation map created using the November 2013 data (Figure 5) is consistent with the
groundwater mapping for the March and July 2013 sampling events.
2.2.5 Private Well Sampling
The variance approval included a requirement to evaluate water quality for 3 wells located south of
Beddingfield Creek (Appendix A). Working with DWQ, the potential sampling area was further
refined. The three sample locations were: 2101 Eason Drive, Clayton; 2221 Eason Drive, Clayton,
and the Tippetts Chapel FWB Church water well at 2530 Shotwell Road, Clayton (Figure 2).
Each of the wells listed above were sampled in 2011 and nitrate concentrations for each well were
less than 10 mg/L. The most recent publicly available data for the Tippetts Chapel (August 2010) well
also indicated a nitrate concentration of less than 10 mg/L.
The monitoring requirements for these wells were satisfied as of December 2011; no additional
monitoring is required.
2,2.6 Subsurface Flow Wetlands Monitoring
The Subsurface flow wetlands were sampled bi-monthly in 2013. Two locations were sampled during
one event (inflow and outflow), and three locations were sampled during the second event: Inflow,
outflow and downstream. Sample results from monitoring of the wetlands are presented in Table 10.
The bi-monthly sampling events found that some initial reduction of nitrate concentrations was
occurring in Wetlands A and C. At Wetland A, the average annual nitrate concentration in the inflow
sample was 12.23 mg1L and the outflow concentration was 8.29 mg/L. At Wetland C, average annual
inflow and outflow concentrations were 36.99 and 27.8 mg/L respectively. The results at Wetland E
were 1.53 mg/L for the inflow sample and 1.5 mg/L in the outflow sample; these values are low
enough to determine that a reduction has not yet been noted. Since the repairs to the intake/dam at
Wetland E are complete and the wetland's functionality has been restored, nitrate concentrations are
beginning to return to what is expected (higher at the intake and lower at the outflow).
Jam,ary2OA

3-1
3.0 Summary and Recommendations
CORPUD successfully completed the 2013 monitoring events for the Neuse River W WTP site.
Following the sampling program requirements accepted as part of the variance approval (Appendix
A), groundwater and surface water quality data were collected for 73 monitoring wells and 24 surface
water sampling locations during March, July, and November 2013. The groundwater containment
system continues to operate successfully, having pumped 15,532,150 gallons of water in 2013, with
an estimated removal of 3,759.89 pounds of nitrogen from the aquifer system. Offsite riparian buffer
restoration performed for the Butlers Branch site during 2010, is credited for removing 4,091 pounds
of nitrogen per year.
The subsurface flow wetlands constructed in 2010 came on-line in 2011 and were sampled bi-monthly
throughout 2013. Wetlands A and C are functioning as designed and nitrate reduction should start
occurring as organic material builds up in the subsurface matrix. Repairs to the existing dam overflow
at Wetland E should were completed early in 2013 with the addition of a concrete pad to the spillway;
nitrate reduction is still too tow to quantify.
Groundwater remediation is ongoing through a combination of groundwater withdrawal/containment in
and around fields 50 and 500, and natural attenuation. Based on review of the data from the 2013
sampling events, documented herein, the following recommendations are provided for ongoing
activities:
• Monitoring should continue using the current monitoring wells and surface water sampling
locations described in this report.
• Monitoring and evaluating the pumping rates and well integrity for wells in the groundwater
containment system. Field inspections are recommended and additional actions will be taken
based on the results of those inspections.
• Ongotng evaluation of the natural attenuation of nitrate in surface and groundwater should
continue through at least 2014.
January=4

4-1
4.0 References Cited
ENSR, 2002. Comprehensive Site Assessment, City of Raleigh, Neuse River Wastewater Treatment
Plant.
ENSR, 2003. Supplemental Site Assessment, City of Raleigh, Neuse River Wastewater Treatment
Plant.
ENSR, 2005. Revised Corrective Action Plan, City of Raleigh, Neuse River Wastewater Treatment
Plant.
Restoration Systems, LLC, and Axiom Environmental, Inc., 2013. Annual Monitoring Report, Year 4
(2013): Butlers Branch Nutrient Buffer Restoration Project, Neuse River Nitrogen Abatement,
Craven County, North Carolina. Prepared for City of Raleigh, NC, November 2013.
Ja ry2014

Appendix A
Approval of Variance Request
January2014

STATE OF NORTH CAROLINA
COUNTY OF WAKE
IN THE MATTER OF:
PETITION FOR VARIANCE FROM }
GROUNDWATER REGULATIONS )
15A NCAC 2L .0107(K)(3)(A) AND )
15A NCAC 2L .0106(J) BY THE )
CITY OF RALEIGH, NORTH )
CAROLINA }
BEFORE THE
ENVIRONMENTAL MANAGEMENT
COMMISSION
FINAL DECISION GRANTING
VARIANCE
THIS MATTER came before the North Carolina Environmental Management
Commission at its meeting on 19 November 2009, in Raleigh, North Carolina.
Commissioners Kevin Martin, Les Hail and Donnie Brewer did not participate in the
consideration or determination of this matter. On June 26, 2009, the City of Raleigh
(Raleigh) applied for a variance to certain State groundwater rules - 15A NCAC 2L
.0107(k)(3)(A) and 15A NCAC 2L .01060). The purpose of the requested variance is to
allow Raleigh to implement a natural attenuation corrective action plan (CAP) pursuant
to 15A NCAC 21- .0106 for nitrate contamination in groundwater that has resulted from
the over application of residuals to fields at Raleigh's Neuse River Wastewater
Treatment Plant. State groundwater rules do not allow natural attenuation as a
cleanup method for permitted facilities; therefore, Raleigh seeks a variance from those
rules.
A public hearing was noticed in accordance with N.C.G.S. § 143-215.3(e) and
15A NCAC 2L .0113(d) and held on 9 September 2009 in Raleigh. Having considered
the whole variance application and comments submitted during the public hearing
process, the hearing officers compiled a report and recommendation for presentation to
the Environmental Management Commission.
Based upon the request for the variance, the comments submitted during the
public hearing and comment period, and the presentations of the parties, the
Environmental Management Commission (the Commission) makes the following:
FINDINGS OF FACT .
1. Raleigh owns and operates the Neuse River Wastewater Treatment Plant in

2
f
southeastern Wake County (the treatment plant). The area for which the variance is
requested is land at and near the treatment plant consisting of approximately 1,466
acres of the treatment plant and 37 parcels of land adjacent to the property along Old
Baucom Road, Mial Plantation Road, Shotwell Road, and Battlebridge Road. Land
surrounding this site consists of residential properties, farmland, commercial property,
and state-owned forestland.' The northern and eastern boundaries border a 3.6 -mile
section of the Neuse River which is classified as Class C NSW (nutrient sensitive
water).
2. The site is situated within the eastern Piedmont Physiographic Province of North
Carolina. Area topography consists of rolling hills dissected by narrow v -shaped
drainage ways and perennial streams that drain into the Neuse River. Localized steep
bluffs exist to the south along Beddingfield Creek and along the Neuse River to the
east and north. Localized bluffs in this area plateau to narrow bench cut alluvial
fioodplains that are nearly flat with incised drainage ways to the Neuse River.
3. Land application operations at this facility are regulated by Biosolids Permit #
WQ0001730. The Permit allows for the application of 7,000 total dry tons of Class ;B
Biosolids per year on fields listed in the permit, subject to a condition added on October
15, 2004, that prohibits all biosolids application at the site until authorized by the
Division of Water Quality (DWQ) via a permit modification.
4. Since 1980, application fields have been added and removed from the biosolids
application program. Several fields owned or formerly leased by Raleigh have been
converted into other uses.
5. Groundwater monitoring required under the Biosolids Permit revealed
exceedances of the groundwater standard for nitrate (10 mg/L nitrate as N), 15A NCAC
2L .0202, at numerous points along and beyond the compliance boundary of City -
owned biosolids application fields. Raleigh suspended the application of residuals on.
their land in this area in September 2002.
6. As a result of over application of biosolids, nitrate in groundwater has exceeded
the 2L standard outside the permitted compliance boundary. In 2002, Raleigh sampled
thirty-nine private water supply wells located in the vicinity of the site. Analytical data
indicated that seven of those wells had nitrate concentrations in excess of 10 mg/L

3
nitrate as N likely resulting from a combination of septic systems, non -City fertilization,
and biosolids application to upgradient fields. Raleigh subsequently began a quarterly
sampling program of private water supply wells located within a half of a mile of the
biosolids application field boundaries and identified forty-five private and/or community
water supply wells.
7. The near -by residents with elevated nitrate in their water supply wells, as well as
a majority of other residents in Raleigh's sampling program, have been connected to
Raleigh's municipal water supply at no cost to the property owner for 20 years. The
private water supply wells have been abandoned consistent with the Commission's
rules, 15A NCAC 20 .0100, et seq. There are four private water supply wells that are
still in use as drinking water supplies. Nitrate concentrations for these currently active
water supply wells have been below 10 mg/L nitrate as N in all sampling events.
These wells are not in the areas for coverage by the variance as they are not likely
receptors for nitrate -impacted groundwater migrating beyond the compliance boundary.
8. Raleigh performed a Comprehensive Site Assessment (CSA) and a
Supplemental Site Assessment (SSA) of the groundwater contamination at the site.
Groundwater analytical data from the sixteen compliance monitoring wells included in
the Biosolids Permit and the 61 additional monitoring wells installed in connection with
the CSA, SSA and CAP indicated that nitrate exceeded the 2L groundwater standard
at locations near the compliance boundary in the areas of Fields 6, 12, 18, 19, 41, 47,
50, 60, 61, 62 63, 74, 100, 201, 500, and 503. The deep saprolite well (MW -113d) and
bedrock wells (MW -101d, MW -105d and MW -111d) also exceeded the nitrate
groundwater standard. Analytical results suggest a potential for nitrate from biosolids
application in Field 50 to have impacted groundwater on the residential property to the
east and in a former private water supply well. Off-site nitrate impacts to groundwater
associated with biosolids application in the vicinity of the intersection of Old Baucom
Road and Mial Plantation Road do not appear to extend significantly east of Shotwell
Road or Mial Plantation Road. Nitrate in groundwater exceeded the nitrate
groundwater standard within Field 500 in the vicinity of former private water supply
wells PW -8, PW -12, PW -30, and PW -36. Analytical data from wells located across
major streams such as Beddingfield Creek, as well as hydrogeologic modeling,

U
indicated that migration of nitrate impacted groundwater under the stream has not
occurred and is not likely to do so.
9. Analytical results of surface water data from several samples collected in first
order tributaries and seeps within the application areas had nitrate concentrations
above 10 mg/L nitrate as N. The nitrate concentrations in surface water suggest
groundwater discharges to the streams and tributaries. However, nitrate levels In a
number of the first order tributaries have declined significantly in recent years and
nitrate in samples collected from Beddingfield Creek and the Neuse River were lower
and did not exceed 10 mg/L nitrate as N.
10. Analytical results of the soil samples collected from Fields 3, 100, and 500
reveal that concentrations of nitrate generally peaked in the 4 to 8 ft depth interval and.
peak concentrations are expected to stay in approximately the same depth interval.
Nitrate appears to have accumulated at the 4 to 8 ft depth interval through mechanisms
such as infiltration redistribution (some water takes a rather slow pathway through the
soil) and anion exchange (nitrate is an anion).
11. An incubation study conducted as part of the SSA estimated the amount of plant
available nitrogen (PAN) in soils in the fields and the residual PAN for the 2003
growing season. The 2003 soil PAN evaluation indicated that approximately 38 fields
would supply PAN in excess of the amount required for anticipated crop production in
2003. Since these fields have been cropped steadily since 2003 without significant
additional nutrient inputs, PAN levels have likely declined substantially, which appears
to be confirmed by declining yields in crop production.
12. Raleigh developed a corrective action plan to achieve full compliance with the
Commission's rules for groundwater corrective action that would utilize "best available
technology" and would actively remediate groundwater exceedances beyond the
compliance boundary. That plan would involve (i) the installation of approximately 380
groundwater extraction wells to hydraulically contain nitrate -impacted groundwater
within the compliance boundary, and (ii) enhanced in situ denitrification of groundwater
beyond the compliance boundary in areas where nitrate concentrations exceeded, or
were predicted to exceed, 10 mg/L nitrate as N. Raleigh determined that the present
net worth of capital and operation and maintenance costs of this alternative over a

5
thirty-year period would be nearly $81 million dollars.
13. Raleigh also developed an alternative corrective action plan which involves (i)
hydraulic containment of groundwater in the area with the highest density of existing
residences immediately downgradient of the site and where some private wells had
mean nitrate concentrations in excess of 10 mg/L nitrate as N; and (ii) long-term
groundwater monitoring and natural attenuation of nitrate levels for the remainder of
the site. Raleigh projects the cost of implementing this plan over a thirty-year period to
be $6.3 million dollars.
14. The areas proposed for a variance are depicted on Attachment 1 which is
incorporated herein by reference. The variance areas are grouped into the following
zones:
Zone No.
Description
Parcel Nos.
1
NRWWTP Site
N/A
2
Waste Corporation of America
Construction and Demolition Debris
Landfill/Common Area of a Residential
Subdivision
5, 18
3
Progress Energy Substation/Portion of
NRWWTP Site
3
4
Clemmons State Forest
1, 7, 17, 32
5
Cemetery
26
6
Private Residences
4, 6, 8, 10, 15, 16, 19, 20,
24,25, 27, 28, 29, 36
7
Private Residences
2,22
8
Private Residences
12
9
Private Residences
13, 14, 31, 16, 35
10
Private Residences
21
11
Private Residences
23
12
Private Residences
30
13
Private Residences
33, 34, 35
15. All of the properties for which a variance is requested, except Parcels 1, 7, 17,
and 32, have public water service or access to public water service should a residence

or place of business be constructed on the parcel. The excepted properties comprise
the Clemmons State Forest owned by the State of North Carolina, which has been
notified of Raleigh's CAP and has given its consent to Raleigh's conditionally approved
CAP as required by the Commission's corrective action rules (see 15A NCAC 2L
.0106(k)(3)).
16. The primary risk associated with the groundwater contamination at the site is
that groundwater with nitrate levels in excess of 10 mg/L nitrate as N would be used for
potable water. The vast majority of the variance areas (Zones 1 though 5) are
comprised of the Neuse River Waste Water Treatment Plant property and other
nonresidential parcels where there is no potential for the use of groundwater for
potable purposes. As noted above, Raleigh instituted a testing program for nearby
private water supply wells in 2002, including all those that are or were in the variance
areas. Testing of these wells detected exceedances of the standard in sixteen wells.
Of those sixteen wells, eight wells had only one test result greater than the mg/L nitrate
as N 2L standard for nitrate. All of those wells, as well as most others that did not
show exceedances, have been abandoned and the residences in question have been
connected to Raleigh's public water supply system. The monitoring, connection and
well abandonment program is incorporated into enforceable conditions in Biosolids
Permit No. WQ0001730. Four private water supply wells in the sampling program are
currently still in use, but monitored nitrate concentrations in those wells have never
exceeded, and are not predicted to exceed, the nitrate groundwater standard. Wells
that were not part of Raleigh's testing program are not at risk from nitrate -contaminated
groundwater as indicated by Raleigh's groundwater models. In addition, Raleigh has
Installed the hydraulic containment system approved in its alternative corrective action
plan. The groundwater extraction system has been operating continuously since
January 3, 2008. This system provides an additional, redundant layer of protection to
the most densely populated variance area where some wells had. mean nitrate
concentrations in excess of 10 mglL nitrate as N.
17. Raleigh prepared a baseline human health risk assessment to evaluate the
potential risk to human health from nitrate -impacted groundwater at the site. The
assessment evaluated potential future use of downgradient groundwater and found

7
r
that there were no unacceptable risks for exposure to groundwater used for a non -
potable purpose (swimming pool) and that there were no unacceptable risks for using
groundwater for irrigation purposes. The assessment found a potentially unacceptable
risk for site groundwater if it were used as drinking water.
18. Some portion of the nitrate -contaminated groundwater at the site ultimately
reaches surface water and, if it resulted in a concentration of nitrate in excess of 10
mg/L nitrate as N in a surface water body used as a drinking water supply, there could
be an effect, on public health. however, nitrate concentrations in the Neuse River in
the vicinity of the treatment plant have consistently been below 0.6 mg/L nitrate as N
and the Neuse River below the mouth of Beddingfield Creek is the only surface water
body in the vicinity that is used as a drinking water supply. Nitrate concentrations at
that location have consistently been below 0.6 mg/L nitrate as N. Thus, granting the
variance would not endanger public health by creating a risk to surface waters used as
water supplies. In addition, the risk assessment determined there were no
unacceptable human health risks for body exposure to surface water on the site.
19. A hydrogeologic study of the site conducted for Raleigh estimated that the
maximum total discharge of nitrogen to surface waters occurred in 2006 at the rate of
148,000 pounds per year via groundwater discharge. Of this total, 34% or 50,000
pounds resulted from groundwater concentrations exceeding 10 mg/L nitrate as N at
the compliance boundary. The remaining nitrate discharge to surface water from
discharges (i) beyond the compliance boundary of groundwater with concentrations
less than 10 mg/L nitrate as N, or (ii) within the compliance boundary are not relevant
to the variance request. Thus, the effect of the requested variance, without any
mitigation, would be to allow a maximum of 50,000 pounds per year of additional
nitrogen to reach the Neuse River via groundwater from the site. This number will go
down overtime as natural attenuation occurs.
20. To mitigate for this potential impact, Raleigh has agreed with DWQ to modify the
NPDES permit for the treatment plant to include a debit against the facility's nitrogen
loading allocation cap (682,483 pounds) under the Neuse NSW management strategy
based on an estimate of the amount of additional nitrogen loading to the Neuse River
that is occurring and will occur in the absence of a fully compliant groundwater

H
n
remediation system. The maximum debit amount of 123,000 pounds per year is
73,000 pounds per year greater than the amount of nitrogen loading to surface water
that would be eliminated in the absence of a variance.
21. Raleigh also evaluated both on-site and off-site nitrogen mitigation alternatives,
including stream impoundments, phytoremediation, subsurface flow treatment
wetlands, and riparian buffer restoration. Raleigh proposes to construct subsurface
treatment wetlands on streams at three locations on the site where nitrate
concentrations in surface water exceed 20 mg/L nitrate as N, which will, based on
current nitrate concentrations, remove approximately 28,500 to 42,800 pounds of
nitrogen annually, assuming removal efficiencies of 50% to 75%. Raleigh also
proposes. to acquire nitrogen offset credits by constructing an off-site riparian buffer
restoration project on a segment of Butlers Branch in Craven County that will remove
approximately 4,000 pounds of nitrogen annually. Raleigh has committed to implement
these mitigation measures Irrespective of the approval of this variance request and
DWQ has modified the Biosolids Permit to make implementation of the mitigation
measures an enforceable condition of the permit.
22. Implementation of the corrective action plan utilizing "best available technology"
to achieve full compliance with the Commission's rules for groundwater corrective
action would employ an extraction system process requiring approximately 380
extraction wells along the portions of the compliance boundary where the nitrate
groundwater standard has been exceeded and/or is estimated to be exceeded, in
addition to piping installed underground, in trenches, along the roads and fields, to
convey the water to the treatment plant. The extraction wells, 12 monitoring wells and
10 surface water samples would be sampled and analyzed for nitrate triennially for the
life of the project (30 years) at an estimated cost of approximately $51,125,400.
23. Application of "best available technology' in the corrective action plan to achieve
the full -compliance alternative would also require the denitrification of the impacted
groundwater beyond the compliance boundaries by the use of approximately 5,760
injection wells constructed in the thirteen zones where nitrate exceeds the 2L standard.
The probable costs for the .enhanced denitrification process component, including
design services, capital costs, operation and maintenance, monitoring and

9
decommissioning, over the life of the project would be approximately $29,967,900.
24. Raleigh's alternative corrective action plan involves the installation and
operation of groundwater extraction wells to prevent further migration of groundwater
with elevated nitrate levels to Zone 6 of the variance areas. Zone 6 consists of densely
clustered residential properties several of which had private wells (now abandoned) in
which mean nitrate concentrations in excess of 10 mg/L nitrate as N were recorded.
Raleigh has installed appropriately -spaced groundwater extraction (recovery) wells
within the compliance boundaries of Fields 50 and 500 at the southeast corner of the
site, upgradient from the Zone 6 variance areas to allow containment of the dissolved
nitrate plume exceeding the nitrate groundwater standard. The extracted groundwater
is being piped to the Neuse River Treatment Plant for treatment. The extraction and
monitoring wells and surface waters will be sampled and analyzed for nitrate as
required by a monitoring plan approved by the DWQ.
25. The total cost associated with the alternative corrective action plan groundwater
extraction process, including design, construction and startup, operating and
maintenance, monitoring and decommissioning is estimated to be $6,358,500.
26. Raleigh's full compliance with the Commission's rules for groundwater
remediation would require that it spend approximately $75 million dollars beyond the
approximately $6.35 million that it will have to spend to implement the "best available
technology economically reasonable" alternative. The majority of the cost to implement
the corrective action plan utilizing "best available technology" to achieve full
compliance with the Commission's rules for groundwater corrective action would be
incurred to remediate groundwater on (i) Raleigh's own wastewater treatment plant
site, (ii) a construction and demolition landfill site, (iii) a remote and largely inaccessible
fringe of a State forest, and (iv) residential properties where Raleigh has spent over
$600,000 providing public water service.
27. According to Raleigh's economic analysis of the costs of the full compliance
plan and the alternative groundwater extraction and natural attenuation alternative
plan, the former could require Raleigh to divert funds allocated to the numerous capital
improvements planned for the treatment plant, thus potentially putting the protection of
water quality and the availability of high quality wastewater treatment service to the

10
area's growing population at risk. This would be a detriment to public health and
outweigh the benefits of the full compliance alternative, relative to the more cost-
effective and more protective proposed remedy. The expenditure required to
implement the full compliance alternative would provide little if any public benefit
beyond that of the alternative plan.
28. The fully compliant corrective action plan could have detrimental effects on the
environment by requiring the installation of approximately 380 pumping wells along
portions of the compliance boundary where groundwater exceeds or is expected to
exceed the nitrate groundwater standard. The hydraulic barrier created by the
extraction wells could result in reducing groundwater discharge and thus stream
baseflow to several streams in the area, particularly Beddingfield Creek. This reduced
flow could be detrimental to the ecology of those streams. In addition, full-scale in situ
denitrification system implementation with 5,760 injection wells will require the
disturbance of significant riparian and wetlands areas around the site.
29. Edge of Auburn, LLC and Auburn Associates (collectively Auburn), who propose
to develop a residential community to the southwest of the wastewater treatment plant
site, have alleged that water supply wells they propose to install would be at risk of
becoming contaminated by nitrate in groundwater emanating from the site. However,
in its comments and submissions during the public comment period, Auburn provided
no evidence to support this allegation. The evidence in the record clearly supports the
conclusion that nitrate from the Raleigh site will not migrate to or cause exceedances
of the 2L standard on the Auburn property.
30. Granting the requested variance, with the conditions described below, will npt
endanger human health or safety.
31. Compliance with the rules, standards, and limitation from which this variance is
sought cannot be achieved by application of best available technology that is
economically reasonable, and such compliance would produce serious hardship
without equal or greater benefits to the public.
Based upon the foregoing Findings of Fact, the Environmental Management
Commission makes the following:

CONCLUSIONS OF LAW
1. Raleigh is subject to the requirements of State groundwater rule 15A NCAC 2L
.0106 for nitrate and has exceeded the State standard beyond the compliance
boundary at the Neuse River Wastewater Treatment Plant. This rule provides in
relevant part:
(a) Where groundwater quality has been degraded, the goal of any required
corrective action shall be restoration to the level of the standards, or as closely
thereto as is economically and technologically feasible. In all cases involving
requests to the Director for approval of corrective action plans, or termination of
corrective action, the responsibility for providing all information required by this
Rule lies with the person(s) making the request.
(d) Any person conducting or controlling an activity which is conducted under the
authority of a permit issued by the Division and which results in an increase in
concentration of a substance in excess of the standards:
(1) at or beyond a review boundary, shall demonstrate, through predictive
calculations or modeling, that natural site conditions, facility design and
operational controls will prevent a violation of standards at the compliance
boundary; or submit a plan for alteration of existing site conditions, facility design
or operational controls that will prevent a violation at the compliance boundary,
and implement that plan upon its approval by the Director, or his designee.
(2) at or beyond a compliance boundary, shall assess the cause, significance and
extent of the violation of standards and submit the results of the investigation, and
a plan and proposed schedule for corrective action to the Director, or his
designee. The permittee shall implement the plan as approved by and in
accordance with a schedule established by the Director, or his designee. In
establishing a schedule the Director, or his designee shall consider any
reasonable schedule proposed by the permittee.
Q) A corrective action plan prepared pursuant to Paragraph (c) or (d) of this Rule
must be implemented using the best available technology for restoration of

12
groundwater quality to the level of the standards, except as provided in
Paragraphs (k), (1), (m), (r) and (s) of this Rule.
2. Raleigh is subject to the requirements of State groundwater rule 15A NCAC 2L
.0107(k)(3)(A) which provides in relevant part:
(K) The Director shall require:
(3) that a violation of.standards within the compliance boundary resulting from
activities conducted by the permitted facility be remedied through clean-up,
recovery, containment, or other response when any of the following conditions
occur:
(A) a violation of any standard In adjoining classified groundwaters occurs or
can be reasonably predicted to occur considering hydrogeologic conditions,
modeling, or other available evidence; and 15A NCAC 2L.0110130).
3. The State groundwater standard for nitrate is 10 mg/L nitrate as N, 15A NCAC
2L .0202(103), and has been exceeded in the groundwaters at and beyond the
compliance boundary at the Neuse River Wastewater Treatment Plant. In the absence
of a variance, Raleigh must implement a corrective action plan to remedy exceedence
of the standard beyond the compliance boundary using "the best available technology"
for restoration of groundwater quality to the level of the standards. 15A NCAC 2L
.0106(1).
4. State groundwater rules 15A NCAC 2L .0107 and 15A NCAC 2L .0106 do not
allow natural attenuation as a cleanup method for permitted facilities, including the
Neuse River Wastewater Treatment Plant.
5. The Commission may issue a variance from its rules, standards, or limitations
for a fixed or indefinite period of time upon finding that:
(1) The discharge of waste ... occurring or proposed to occur do(es) not
endanger human health or safety; and
(2) Compliance with the rules, standards, or limitations from which variance is
sought cannot be achieved by application of best available technology found to
be economically reasonable at the time of application for such variance, and.
would produce serious hardship without equal or greater benefits to the public,
provided that such variance shall be consistent with the provisions of the

13
Federal Water Pollution Control Act as amended ....
N.C.G.S. § 143-215.3(e).
6. The Commission, pursuant to a request under N.C.G.S. § 143-215.3(e), may
grant a variance to the groundwater classification and standards set forth in
Subchapter 2L of its rules. 15A NCAC 2L .0113.
7. Impiemehtation by Raleigh of the corrective action plan utilizing "best available
technology" to achieve restoration of groundwater quality at this site and relevant
property to the level of the 10 mg1L nitrate as N nitrate standard within and beyond the
compliance boundary is not economically reasonable at this time.
8. In this limited situation, compliance with the rule that does not allow natural
attenuation as a cleanup method for permitted facilities would produce financial
hardship to Raleigh's wastewater treatment utility without equal or greater benefits to
the public or the environment.
9. The variance requested by Raleigh is consistent with the provisions of the
Federal Water Pollution Control Act, as amended.
10. The Commission concludes that Raleigh has met the criteria for a variance
established by N.C.G.S. § 143-215.3(e) and 15A NCAC 2L .0113. The requested
variance allows for the implementation of a corrective action plan reflecting utilization of
the best available economically reasonable technologies available to Raleigh. The
Commission further concludes that continued application of the existing technologies
and resulting reduction of nitrates in the groundwater do not endanger human health or
safety, and are economically reasonable and will not cause unnecessary economic
disruption to Raleigh's capital needs of this wastewater treatment facility.
Based upon the foregoing Findings of Fact and Conclusions of Law, it is
HEREBY ORDERED that:
1. Raleigh's request for a variance is GRANTED, pursuant to N.C.G.S. § 143-
215.3(e) and 15A NCAC 2L.0113, as a variance to rules 15A NCAC 2L .0106 and 2L
.0107 to allow the implementation of the corrective action plan utilizing natural
attenuation with groundwater containment with conditions as described below.
2. The conditions described below shall be incorporated into permits that Raleigh
currently holds, as noted below, and, within 60 days, Raleigh shall formally seek

14
i
amendment of the permits to incorporate conditions set forth herein.
3. NPDES Permit No. NCO029033:
Implementation of the Total Nitrogen debit to the facility's nitrogen loading
allocation cap (682,483 pounds) under the Neuse NSW management strategy
established in the NPDES Permit No. NC0029033. The Total Nitrogen debit may
be revisited at a frequency as determined necessary by the DWQ and modified
upon the review of sufficient information to support such modification.
4. Non -discharge Permit No. WQ0001730:
(a) Continued operation of the active corrective action system; designed to
remediate Nitrate — Nitrogen contaminated groundwater near the intersection of
Mial Plantation Rd and Baucom Rd. The pump and treat system shall operate
until such time as DWQ determines, based on monitoring data that indicates
restoration of groundwater has occurred to the level of the standards for
Nitrate -Nitrogen, referenced at 15A NCAC 2L .0202, for all areas outside of the
Compliance Boundary associated with Fields 50 and 500. Any modification to
the active corrective action system designed to enhance the system
effectiveness, proposed by Raleigh or requested by the DWQ, shall be
implemented upon approval by the DWQ.
(b) Complete installation and operation of the agreed upon subsurface flow (SSF)
constructed wetlands as proposed in the report titled "Proposed Subsurface
Flow Constructed Wetlands, Neuse River Wastewater Treatment Plant,
Raleigh, NC," received January 23, 2009, and as modified or otherwise
approved by the DWQ.
(c) Implementation of the agreed upon riparian buffer restoration work associated
with Butler's Branch in Craven County, as approved by the DWQ.
(d) Implementation of a groundwater and surface water monitoring plan sufficient
to evaluate the effectiveness of the natural attenuation of Nitrate -Nitrogen
originating from the former residuals application fields, the effectiveness of the
SSF wetlands' removal of Nitrogen from surface waters, and the effectiveness
of the pump and treat corrective action systems' restoration of Nitrate—Nitrogen
impacted groundwater. Groundwater and surface water monitoring shall be

15
conducted of the locations and frequency specified by the DWQ in Attachment
"2" Any proposed changes to the monitoring plan shall be submitted with
justification to the DWQ for approval.
(e) Installation of additional monitor wells as specified in Attachment 2 to address
concerns expressed by Auburn and the NC Department of Public Health, to
replace monitoring points determined to be insufficient as not having shown
sufficient groundwater to enable collection of a sample, and to address gaps in
the monitor well network. The Division of Water quality (DWQ) will work with
the City of Raleigh to identify for additional sampling private well owners in the
area south of Beddingfield Creek and west of Mial Plantation Road/Shotwell
Road.
(f) Beginning in January 2014 and every five years thereafter, Raleigh shall
evaluate the effectiveness of the overall remediation strategy required herein to
determine if new or additional treatment technologies exist that could be
implemented cost-effectively while maintaining safety of human health and the
environment. These evaluations and reports shall also include review of
modeling results against observed data. Collection of additional data and
information to improve model calibration or to better evaluate potential
treatment technologies may be requested by the DWQ.
(g) These five-year evaluations shall be reported to the DWQ Raleigh Regional
Office APS one year prior to expiration of Non -discharge Permit No.
WQ001730. The first report shall be due March 31, 2014. The DWQ will report
results of the five year evaluation to the Commission every five years beginning
in 2014.
(h) Specific monitoring and reporting requirements are further detailed in
Attachment 2 which may be modified by DWQ as necessary to implement this
variance.
5. The Commission, at request of the DWQ or upon its own initiative, may reopen
this variance to address potential changes to its terms or conditions in light of new
information or changed circumstances.

This the tjld y of January, 2010,
ENVIRONMENTAL MANAGEMENT COMMISSION
eph n T. Smith, Chairman

17
CERTIFICATE OF SERVICE
This is to certify that this day the undersigned served a copy of the foregoing
FINAL DECISION GRANTING VARIANCE upon the City of Raleigh and the Division of
Water Quality in the manner indicated below. A copy of the foregoing FINAL
DECISION GRANTING VARIANCE also was served upon Edge of Auburn, LLC and
Auburn Associates in the manner indicated below.
Steven J. Levitas, Esq, CERTIFIED MAIL
Kilpatrick Stockton LLP RETURN RECEIPT
3737 Glenwood Avenue, Suite 400 [Electronic Delivery]
Raleigh, N. C. 27612
Counsel for the City of Raleigh
Ms. Coleen Sullins HAND DELIVERY
Director Division of Water Quality [Electronic Delivery]
612 N. Salisbury Street
Raleigh, N. C. 27602
Thomas C. Worth, Jr., Esq. CERTIFIED MAIL
127 W. Hargett Street, Suite 500 RETURN RECEIPT
Raleigh, N. C. 27602 [Electronic Delivery]
Counsel for Edge of Auburn, LLC
and Auburn Associates
This the 15i4`day of January, 2010.
ROY COOPER
Attorney General
Francis W. Crawley`
Special Deputy Attorney General

Attachment 1

Attachment 2
Reporting Requirements
• An annual report will be submitted on or before the last business day of January of each
year, summarizing and InIeroptlog the data collected the *p-r-evious,year (preceding March,
Ju . ly, and November). The initial report shall be due Janvar.y,31, 2010.
• Each annual report shall summarize and Interpret, .the. ditafrom the sampling events,
discuss the status and provide recommendations regarding monitored natural attenuation,
the pump and treat system, the subsurface flow wetI6hdp,and.the.off-slte riparian buffer
restoration activities.
The annual monitoring. -report. should be based on the.monitoring report template from the
DWO guidance document prppridwater Section Guk:1ejIn94 for the investigation and
Remediation of Soil and Groundwater, July 2000,
- The report shall Include a table of current groundwatey an.d.surface water sampling data
for each sampling event,:p table of groundwater elevations
104tions for each sampling event, a
map of corresponding groundwater elevations at ea. chn', a map of nitrates nitrogen
concentrations for each event, and a table compiling , t ,a
ihistorical nitrate as nitrogen
concentrations.
- Each annual report shall .also Include a summary,;table of the well construction
specifications of all monitoring wells In the monitoring plan. The table shall Include the
following Information: installation date, total depth, well diameter, casing and screen
length, and depth of screened;Interval.
• Three copies of each annual report shall be sent to th e-I)WQ -Aqulfer Protection Section,
Raleigh Regional Office.
• Results of subsurface flow wpliande.monitorIng shall be: submitted quarterly for the first year
and each year thereafter as part of the annual report.
Groundwater Monitoring Schedple.and Parameters
• Groundwater monitoring shall be. conducted three times a year during the months of March,
July, and November.
• For each monitoring event, the water level in each monitoring Well In the required monitoring
network will be measured and recorded prior to purging,

Attachinent 2 cont
During each monitoring event, each of these wells will be sampled and analyzed for the
following parameters: temperature, pH, specific conductivity, dissolved oxygen, and nitrate -
nitrogen.
Corrective Action Groundwater, Monitoring Network
Include the compliance wells in Permit No. WQ0001730 In the corrective action monitoring.
These wells are MW -13, MW720, MW -22, MW -41, MW -42, MW -44, MW -45, MW -46, MW -
47, MW -48, MW -49, MW -50, MW -51, MW -52, MW -53, and MW -54.
The permit compliance sampling schedule Is the same as the recommended monitoring
schedule (March, July, and November of each year).
Continue sampling and monitoring the existing groundwater monitoring wells shown in
Figure 1 the Groundwater Corrective Action Variance Application (June 26, 2009).
- All "active monitoring wells" listed on Figure 1: TW -1, TW -2, TW -9, TW -11, TW -14, TW -
16, TW -18, TW -24, TW -25, TW -30, TW -30.1, TW -31, TW -31 A, TW -32, TW -32A, TW -33,
TW -34, TW -35, TW -36, TW -37, TW -45A, TW -642, MW -100, MW -101, MW -101D, MW -
102, MW -103, MW -104, MW -105, MW -105D, MW -1.06, MW -107, MW -108, MW -109,
MW -110, MW -111, MW -111D, MW -112, MW-113D,'MW114, MW -115, MW -116, MW -
117, MW -121, MW -122, MW -122D, MW -123D, MW -.124D, MW -125D, MWA26D, MW -
127, MW -201, MW -202, MW -203, GP -1, GP -3, G13-5,.G.P-8, GP -9, GP -10, GP -12, GP -
17, GP -21, and GP -22.
Replace monitoring wells In this network that are chronically dry with deeper wells, Use
existing water level information to plan replacement well depths such that well would not
be expected to be dry under typical seasonal conditions,
After reviewing the "Remediation and Non-compliance Well Data" received on August 31,
2009, DWQ identified several "active monitoring wells" as chronically dry such that water
quality parameters could not be collected, For this review, "chronically dry" was defined
as the well being listed as "dry" three or more times during the time period from January
2007 through July 2009 on a sampling schedule three times each year (March, July, and
November). These wells are TW -1, TW -2, TW -14, TIN -16, TW -31A, TW -45A, MW -104,
MW -121, MW -124A, GP -1, GP -3, GP -5, GP -8, GP -10; :GP -12, and GP -22.
Specifically, it is recommended that monitoring wells ,MW -121, MW -104, and GP -3 be
replaced with wells screened In partially weathered rock or bedrock.
The existing wells at the site arepredominantly shallow. and screened in saprolite, To
address concerns about the nitrate Impacts to deeper groundwater In thepartially weathered
rock and bedrock aquifers, the Installation of additional deep wells Is recommended in
several locations.
Install a deep well screened In partially weathered rock south of Field 60, near or
adjacent to existing well MW -48.
Page 2 of 4
I

Attachment 2 coni
Install a deep well screened In bedrock near or adjacent to existing well MWA 12.
Install a palr of deep wells screened 1) in partially weathered rock and 2) in bedrock
along the western edge of Field 74 at a point approximately halfway between existing
wells MW -122 and MW -49.
• Several private residential wells in the housing development located south-southeast of
Field 201 will be sampled and analyzed with other monitoring samples. The City of Raleigh
will work with the regional office staff to identify private .well owners in the area south of
Beddingfield Creek and west of Mtal Plantation Road/Sholwell Road.
• After reviewing the well construction for the wells in the network as described in Reporting
Requirements), DWQ willworkwith the City to eliminate. potentially redundant sampling
locations. NOTE: This is specifically in reference to the large number of TW wells such as in
Field 602,
Groundwater Monitoring Well Construction Requirements
• All monitoring wells Installed should be screened with 10 feet to 20 feet of screen across
water -bearing fractures or units at discrete Intervals. From this time forward, deep wells will
not be Installed with open boreholes.
• Where wells are installed In, pairs (such as deep and shallow), the wells in the cluster should
be screened at discrete Intervals to avoid overlapping zones,
• Existing water level information should be used to plan well depths to avoid chronically dry
wells,
• In accordance with 15A NCAC 2C ,0102, all temporary wells must be converted to
permanent monitoring wells within seven days of completion or they shall be abandoned.
Surface Water Monitoring Schedule, Locations, and Parameters
• Surface water monitoring will be conducted three times a,year during the months of March,
July, and November.
• Surface water monitoring will ,be conducted as the surface water locations shown and
Identified in Figure 1 of the Groundwater Corrective Action Variance Application (June 26,
2009), These locations include: SW -1, SW -2, SW -3, SWA SW -S, SW -6, SW -7, SW -8, SW -
9, SW -10, SW -11, SW -12, SW -13; SW -14, SW-115,SW-.10, SW -17, SW -18, SW -19, SW -20,
SW -21, SW -22, SW -23, SW -24, SW -25, SW -26, SW -27, SW -AU, SW -AD, SW -CU, SW -CD,
SW -EU, and SW -ED.

Attachment 2 con't
• During each monitoring event, each of the surface .water monitoring locations will be
sampled and analyzed for the following parameters; temperature, pH, specific conductivity,
dissolved oxygen and nitrate-nitrggen.
Subsurface Flow Wetland Monitoring
The subsurface.flow wetlands will be monitored as specified in the monitoring plan
presented in Section 3.1 of the. Proposed Subsurface Flow Constructed Wetlands,
Neuse River Wastewater Treatment Plant, Raleigh, NC;(December 20.08), or as
otherwise approved by the DWQ Raleigh Regional Office..'
Page 4 of 4

IVA
CDMR-
Na1th Carolina 1llepart1n011t of B11•v 0mile11t and Natural'Rosomaes
Division ar•Virnlor Qunfft
BOvorly Bavos Porduo Coloon M Sullins y Don Freeman
Qoverllor Director Secretary
8uptcmber2,2010. � '
OM1'1f QM MAIL,
1UTIMN 91'CISIU 1ZnrrnSTBD
Mr. J, RusHali Alton, City Manager
City of Roloigh
222.Wotllargottstreet
P.O.'Box 590
R01e1811, NC 27602
SUBJECT: Corrootivo Aottou Plan (CAP) Final Approval
Nam River Wnstowater'Proalmout Plant
Ino 1186477., Non-Olsahargo Pormit it WQouoI73o
Wake County
Dom' Mr, Russoll:
On June 26, 2009, the City of Raleigh applied for a vnrinnoo to cortahi State groundwator rules loonted Jn'1'itle
15A, Norfli Cordlin Administrotivo Cade, Subol ap'lar 2L, .0100 (15ANCA C 2L) fortho purpose of.
lmpiomanting a Corrective Action Plan (CAP) meeting tho raqulroments of 15ANCAg 2L ,0106. Corrective'
action meusures propelled in tho varinuce apPtloatiol hlaludod the implomentutiou of a natural attenuation plan
with monitorhtg, continued Implementnitou of the gronndwnlar raoovel� ayataln loentedat Mint Pinntadnn nud
flnuuom Roads, i OMIntion of subsurlhoo flow wotlands and riparian buffer restoration efforts along g segment or
Butiol�'sBrnnoh In Ghnvon County. On January lq, 201.0, the 13uvh'onmantnl i4lunngemant Cotnnllsalou (IIMC)
signed the 'Th) lDeolsion.Ornnting•Varinndo" (Varinnoo) in the nlattor Of 010 "Polltionfo• Vorlanoe fPom Cn'ound
WntorRogulations 15ANCAC 2L .0107(k)(3)(a) nud 154 NCAC 2L ,0106(#) by duo City ofltnloigh Nortil
Carolina." Tide ruling ordered, in;pila,that:
ltnlolgh's roquait for a vnrinnoo is ORANT11D, pm'snant to N.C.G.S, § 143-21i3(0) mid 15A
NCAC 2L .0113, n§ 0 vnrinnoo to rnira .15A NCAC 2L .0106 and 2L .0107 to allow tile
Implomontolion of the oorrootivo action plan utilizing natural attenuutiolr'with groundwater
oontalnmantwith oonditions...
Based upon n review of the final Valance doolsioa o1'.thoAMC, Information submitted In the CAP, and nlior
oonsidering any public comments and the Raleigh Regional OftMoo recommendations, I am horaby gronling final
f 1617 "tall ST'Nlnn Caalor, auloiga. Nm@ CM1111A 2'1699.1617
.uonnmr. 512 N, SoIMUinyy SL nnIe1HU, korlb Carolitln 27601 .One
Ptinue:919-ee'RG3Qe1 VAY1919•ea7.6d921 Ce4IvmCrBan'Ice t•877fi2;f•67AH � ��A.��
intralCl: lvvrv.rtouvnlormmllluurc [�' /'� ��
dl, annul Cinnnr✓IlnllVl /lalniNllYn AMIAn n111n(nvN' •�"�""��

Nouso War Wasicwslor'1Trennneat Plant
Sopteiabor 2, 2010
pnge'l. of 3
approval to Implement the CAP. This approval is eoatingeut upon the Conditions speolfied in etre Variance, vvhieh
arts briefly sumtnarixadas foliowst
'n, implementation of the Total Nitrogen debit to Ore facility's nitrogen landing alloentlon onp (682,4113
pounds) under theNonso NSW munagemoat strategy estobilsbed in theNPDES Porm(tNo. r
NC0029033,
b. Continued operation of the 1100VO aorraotivo nation system, designed to ramedinteNitrate -Ni4'ogcC
oontaininated groundwater near Ora intorsootion ofMinl Plantation Rd gild Bnuoam Rd, until suoh
time as AWQ determines t1mtrost0r00on of groundwater has 000urrod to the level of the slandorda
for Nitro to-Nitrogon, raforonced at 15A NCAC 2L.02t12,
a. Complete installation and operation of tits subsurfaao flow (SSF) mistrustedwotlando as proposed
In the report ittled "Proposed Subsurrnoa Plow Cousiroated Wetlands, Naune River Wastewutor
Treatment Plant, Ruioigh, NC," rcaolvod immary 23, 2009, and as modified or otherwise approved
by OieDWQ,
d, Implementation of Ore agreed upon riparlmrbufrer restoration work gseoointed wilitButler's Brmtolt '
in craven County, us approved by tho DWQ.
e, implementation of a groundwater and surfaoo Water monitoring plan in nccordanoo widr and at the
laxations nnd.ftoquonoy apaoified by Ota DWQ In Attaolimont 2, Any proposed ohanges to the
monitoring plan shall be submitted with justt8catlon to die DWQ for npprovnl,
f, lnstallntloit iii additional monitor wolls as apooifidd in Attauhment2 and roplaoantent of monitoring
points determined to be insufftaiant beenaso tiroyroudnely do nothave sufficient groundwater to
enable aolteotion of a sample.
g, DWQ will continue to xvarlc with Ota City of. Raleigh to identify private wall owners In die area
south of Eoddhigfiold Crooli and West of Mini Plantation RoadMotwoll Rood for additional
smupihtg,
b. Every five years, ilio ofroodVeness of -the overall remediation strategy sball be evalunted to dotormino
Ram or additional trontrnant toohnologles exist that oonid be im@iwnonted cost cffootively while
maintaining safety of buntnn 11011101 and Ulu onvironmeirt. The five•yoor evaluation shell be reported -
to the DWQ Raleigh Regional Offloe APS one year prior to expiration ofNon-dlsohnrge Permit No.
W0001730, The first report shall be duo Moroi 31, 2014, The DWQ will report results of Oto flvu
your ovaluadon to tho Commission avert' fivoyonrs beginning in 2014,
i, Speolflu monitoring and roportinglogtiliromonls aro iltrlhor doinlled in Attuohmogt 2 which may be.
modified -by DWQ as necessary to implomcnt the varluuoo.
Upon implementing filo mensnros speoi£ied hi Ole varionoe approvul, YOU may be required to poribrm additional
monitoring, conduat additional alto moossmont activities, assess the performance of the ongoing correolivo gallon,
and/or ovalaato the technological and eoonomioal thosibllity of Implonenting a new teolmology at the subjeot alto,
you are required by 15ANCAC 2L ,0114(o) tonotily till interested pokfiell, as speoified In paragraph (b) of Orol
ride, diet approval of pie CAP was gmnlad by Oro Dlreotor. Notification is required by oortified mail and must be
mado within 30 Allyn of reeolpt of the Diroetor's deolsion,

N0118e1livor WnsiClynterTraannont Plant
8cp1anbor2, 2010
Page of
Pursuant to iSANCAC 2L ,0110 and tho Varlaneo, you are ragnired to hrnplennunt a monitoring plan as follows:
1. Oronndwnior monitoring shall be Can duoted three tiaras n year (luring Mnrob, July, and Novomber.
2. SurlhocWater monitoring 31101, bo Oondnoled ttuee ttmos a your darbtg Maroh. July, and Novembor.
3. An annual report must be submitted to the APS RRO oat of betbro the lust day of janunly datutltug the
groundwater find surface water monitoring conducted durbtgMaroh, July, find Novombor of the
previous year.
Additional monitoring roquirentonts aro spoelilud by DWQ in AttoOhment 2 of Ole Vmimtoo, As notod In the
Vartnneo, Soy proposod Changes to the monitoringplfin Shalt be submitted to DWQ for fipprovuL On April 29,
2010, ABCOM North CaroOnd, on behalf of Ota MY of Ratoigh, proposad Changes to the groundwater and
surf0oo cantor monitoringlOonOons in lite Corrcotivo Aotion Flan tyoniioringNbtwork, After reylowing those
o11nnges, DWQ -approved soma of the Changes in n lotto( dntod Juno 14, 2010. Arevised version of Atthohment 2
Ortho Vnrianoe Out bnolndos these approvod moditiontions is nRnohed hr Otis Ictloribrroreronoe.
Failure to adhere to the requirements of tho Vadnnoe, CAP, and this approval letter may bo oonaildorad to be, n
W0111110rt DMO rules, subject to possible 011forooment notion by the Dlvision.
If you huvo any questions, plenso Conhtut Jay Zimmerman of the Raleigh Reglonat Oft9oo at 919.7914200.
Sincoroly,
Coleenil, Sul ms
co: joint Robert Carman, Public Utilities Dircutor, City ofitalolgh
Tkn Woody, Reuse Superintendent, City of Rulolgh
Ted Dash, Agniibr Frotootion Scotlon Chief
Jny ZlmmOrmnn, Rn 1018h Regional Aquifer Protcotlon Supervisor
Stove Loy11110, YJlpntriok Stookton, L,L,P,
RRO, APS filo

RE *ISE, Attachment 2
This is a revised version of the Variance Attaohmont 2 based ori changes to the Corrective Action
monitoring nethvork.approved by DWQ in a letter dated June 14, 2010. Monitoring locations and
text that have been removoti Rol" tte plan are, stricken through (for oxample "MAV -#0P).
Additions td this document are underitned'(forexamplc"Y 12 tine 1).
Reporting Requirements
An annual report will be submitted on or before the last business day of January of oath'
year, eummariztng and interpreting the data colleotoc( tha•prevlous year (preceding March,
July, and November), The Initial report shall be due January 31, 2010.
• Each annual report shall summarize and Interpret the data from the sampling events,
discuss the status and provide recommendations regarding monitored natural attenuation,
the 'pump and treat system, the subsurface flow wetlands,, and the offsit9 riparian buffer
restoration activities,
The anpual monitoring report should be based on the monitoring report template from the
DWQ guidance document Groundwater section Guidelines for the Investigation and
Remediation of Boll and Groundwater, July 2000.
The report shall include a table of current groundwater'and surface waiter sampling data
for each sampling event, a fable of groundwater elevations for each sampling event, a
map of corresponding groundwater elevations at each event, a map of nitrate as nitrogen
,concentrations for each event, and a table compiling historical nitrate as nitrogen
concentrations,
Each annual report shall also Include a summary table of the well construction
specifications of ali'monitoring wells in the monitoring plan. The table shall ingtude the
following information: instellalion .date, total depth, well diameter, casing and screen
length, and depth of smooned interval.
• Three ocpids or each annual report shall be sent Wthe DWQ — Aquifer Prolectlon 5oction,
Raleigh Regional Office,
e Results of subsurface flow wetlands monitoring shall be submitted quantoriy for Met . lrotyoar
and each year thereafter as part of the annual report,
Groundwater Monitoring Schedule and parameters
Groundwatef monitoring shull be conducted three times a year during the months of March,
July, and November.

REVISED Attaolnnent 2 coni
• For each monitoring event, the water level in each monitoring well in the required monitoring
network will be measured and recorded prior tb purging,
• During each monitoring event, each of these weds will be sampled and analyzed for the
following parameters: temperature, pH, spsolflc.conduottvily, dissolved oxygen, and nitrate -
nitrogen,
Corrective Action Groundwater Monitoring Network
• include the compliance wells in Permit No. WQ0001730 In the corrective action monitoring,
-- These wells are MW 13, MW 20, MVV -22, MW -41, MW -42A, MW -44, MW -46, MW 46,
MW -47, MW48, MW -49, MW50, MW -s1, MW52, MW�ti3, and MW54,
- The permit compliance sampling schedule is the eamo as the recommended monitoring
Schedule (March, July, and November of sect, year).
• Oonllnue sampling and monitoring the existing groundWater monitoring wells shown In
Figure 1 the Groundwater Corrootivq Action Waunae Application (June 2E, 2009),
-- All "active monitoring wells" listed on Figure 1: TW -1, TW 2{q�� 7.W 14, TW.1e, TW18, T34, TW�25, TW30, TWso.1 7'-W ,"' Z, TW 32,-TV42A_,W.,
33, TW -34, TW 45A, 0T+-(,42,, it1W100, MW101, MW -101D, ,
MW -102, .MW 109,. MW -104, MW 105, MW -105D, MW -loo, tvIFW-i", •MWid9,. MW
109, MW1101 MW'411, MW111Di M.W 112, W11013, MW114, MW -115,. MW -116,
HW -10, MW -121, MW -122, MW -1220, MW -120D MW 1241), MW -125D, MW128D,
MW -127, MW -2o1, MW202, MW -;203, Op"1, Gp•3, GP.S, Gp-0, GF�9, Op -10, OP -12,
GP 14, Op 21, and OP -22,
Replace monitoring wells In this nelwori( that are chronically dry with deeper wells, Use
existing water level Information to plan replacement well depths such that well would not
be expeoted to be dry under lypfoal seasonal conditions,
After reviswing the "Remedlatton and Non.compltence Well pale" received an August 31,
2009, i?W.q.identified several "active monitoring wells" as chronically dry such'that water
quality parametere•could not be cotlsctad. For this review, "chronically dry" was defined
as the well being listed as "dry" three or more times duds g the time period from January
2007 through July 2009 on a sampling schedule three times each year (March, July, and
November), These wells are TW -1, TW -21 TW -14, M-18, IZW-3M, TW -45A, W1104,
MW121,WAV4a4Arl,W..�, OP -11 OP -3, GP -5, OP -8, OP -10, QP -12, and GP -22,
- Specifically, It is recommended that monitoring wells MW -121, MW 104, and OP -3 be
replaced with wells screened in partially weathered rock or bedrock,
• The existing welts at the site are predominantly shallow and screened In saproilte, To
address concerns about the nitrate impaata to deeper groundwater in the partially weatherad
Pago 2 of

R)WISE D Attachment 2 con't
rock and hedrock equifers, the Installation of additional deep wells is recommended in
several locations.
-• Install a deep well screened In partially weathered rock south of Field 80, near or
adjacent to existing well MW -48.
— Install a deep well screened In bedrock near or adjacent to existing well MW -1.12,
•- Install a pair of deep wells screened 1) in partially weathered rook and 2) In bedrock
along the western edge of Field 74 at a point approximately halfway between existing
wells MW -122 and MW -49.
+nvewd U g� private residential wells In the housing development located south-
southeast of Field 2010111 be sampled and analyzed with other monitoring samples, far un
to tlia.a Morita ing events, Ths City of Raleigh will work with the regional office staff to
identify private well owners In the area south of Bepdthgfleld Creek and west of Mist
Plantallon Road/Shotwell Road. T,,,liotiponILg1ug data w1i1 be inclndod as part of tile-
ammat monitoring renork
+ After reviewing the well consirwHon for the wells In the network (as described In Reporting
Requirements), DWQ will work with the City to ellminate potentially redundant sampling
Ieaatlene, NOTR; This Is speolfically in reference'to•Ihe large number of'rWwalls such as In
Field 002.
Groundwater Monitoring Well Constructlon Requirements
All monitoring wails installed bhould be screened with 10 foot to 20 feet of sarean across
water -bearing fractures or units at discrete Intervals. From this timo.forward, deep wells will
not be installed with open boroboies,
• . Where wails are Installed in pairs (such as deep and shallow), the wells in the cluster should -
be soreenod at discrete intervals to avoid overlapping zones,
Bxlsting water level information should be used to plan wall depths to avoid chronioally dry
wells.
.
'in accordance with. 16A NCAC 2C .0102, all temporary wells must be gonvortod to
permanent monitoring walls within seven days of completion or they shall bo abandoned.
Surface Water Monitoring Schedule, Locations, and parameters
+ Surfap water monitoring will be conducted three times a year during the months of March,
July, and November.
. Surface water, monitoring will be conducted as the surface water locations shown and
Identified In Figure 4 of the Groundwater Corrective Action Variance Application (June 20,
Page 3 of 4

REVISER A,ttaohment 2 won't
2000). These locations include: SW -1, SW -2, 9W-3, 6*4, SW 5, ,SW..G, sW.7, W-8, sW
91-0,- ! 1 dh4Ak! Y� Q
'-l*' M,SW44, SW -1G, SW T0; $W- 17, $"'5819, 8W-
20, SW 21,•SW 22, SW -23, SW -24, SW -28, $W-20, SW -27, SW -AU, MAD, SW -13u, $W
BD, SW -CU. SW -013, SW -DU, SW -DD, SW -M, and 8W -ED. -
► During each monftoring event, each of the surface water monitoring locations wifl be
sampled and analyzed for the following parameters: temperature, pH, specific conduaiiviy,
dissolved oxygen and nitfate-nitrogen,
Sobsurtace Flow Wetland Monitoring
Tho subsurface flow watiands will be ihonitored as specified in the monitoring plan presented In
Section 8,1 of the Proposed Subsurface FIoW Consiructed Wetlands, Nouse River Wastewater
Trealmont Plant, Raletglt,. NO (December 2008), or as otherwise approved by the DWQ fial01gh
Regional Of(IW.-Tbeso monttorl�ig dots will bo it ch doil es ting. or tpo nnnun r�onit__ or i
�a a
Psge 4 of

Attachment 2.—Modeled and Observed Time Histories of NO3 through 2013
for Active Remediation Extraction and Observation Wells
MA

100
RW -1
1 -}-A
Dec -79
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
LM?
100
--
■ RW-20bservedITMT.-
'
—Model
-
t,
iii
i
E
10
i
Upgradient Fields: I
I
Dec
-79 Dec -89 Dec -99 Dec
-09 Dec
-19
Dec
-29 Dec
-39 Dec
-49
..

100
RW -3
1
Dec -79
100
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
RW -4
■ RW -4 Observed I ---_
—Model
E 2-
10
Upgradient Fields:
I i
500,201
i
1
Dec -79
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
9

RW -5
100
- .. _ - j ■ RW -5 Observed
' 1 —Model i
E
O
Upgradient Fields: 500,
201
1
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
RW -6
100 ... .. ..
■ RW -6 Observed
I _
1 a: —Model -
..
E
10
Upgradient Fields: 500,
201
i
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
90

a
RW -7
100
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
RW -8
100
m
E
m 10
O
Z
1
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
M

RW -9
100
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
RW -10
100
T Upgradient Fields: 500,
201 - ■ RW -10 Observed
1
—Model
c I Ii I
E �v
Z C. r =
fftli }1Ef
92
Dec -79
Dec -89 Dec -99
Dec -09 Dec -19
Dec -29 Dec -39 Dec -49
92

RW -11
100
upgradient Fields:
■ RW -11 Observed
Model I
10--
O
f
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
100
m
E
M 10
O
Z
1
Dec -79 Dec -89 Dec -99
RW -12
Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
93
—
■ RW -12 Observed
UpgradentFields:
500, 201
-
—Model
-
i
' I
'
i
I
I
I
Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
93

100
Q
E
,h 10
O
Z
RW -13
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
100
E
E
M 10
O
Z
RW -14
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
m

100
1 -I—I—
Dec-79
RW -15
j
_ 1
Upgradient Fields: ■ RW -15 observed
—Model I
' I
1
I I��Iil
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
RW -16
100 - . . ... .:..
Upgradient Fields:
500,201
■ RW -16
Observed
—Model
PI
E r ry
Dec-79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49

RW -17
100 .. ..
UpgradientFields: ® RW -17 Observed
500,201
'I Model
i
I
m-- — t --- —`
O
I
.
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
RW -18
100
E
10
O
Z
1
Upgradient
I- - - ■ RW -18 Observed -
Fields: I _ —Model
w
I ,
ill1
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
m

100
RW -19
I �I
I , I
1
Dec -79 Dec -89
Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
100
r Upgradient
j Fields:
I ,
I i
m '
£ 10 - - --�-- -- . a
m
O
Z
I
RW -20
I I
I I'
IMF
- c rt - L--
■ RW-200bserved
—Model
I
I
I 1'
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
97

E
RW -21
100
100
E 10
0
1
1 4— I! I _f L _,- I 11 I 1 I I I I I i 1 I I I I I 1 I I 1 I I I I 1 1 1
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
RW -22
Upgradient Fields: -. l
� I ■ RW -22 Observed
500,201
I —Model
1
i _
i
- I
1
Dec-79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
m

RW -23
100
Upgradient Field: - 0 RW -23 Observed - -
50
—Model
10
z 4
l l i I - - I I ��♦ l l
L
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
RW -24
100
Upgradient Field: - - ® RW -24 Observed -
50
—Model '
E
E10
I
LI---�--
Dec-79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
r"

100
m 10
O
Z
RW -25
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
RW -26
100
Upgradient
Field: 50
I
I•
E 10 ------ - --- ■ RW -26 Observed
jlll-- --- ---
z Model
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
100

10(
m
E
O 10
Z
1
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29
RW -27
100
1
RW -28
Dec -39 Dec -49
1111
1111 JIM 111111111
Upgr
Feda6ont I ~I1� I
I
i
- L -i -- - i� ■ RW -28 Observed i
I
i —Model
-
�IL
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
101

RW -29
100 .. .
i
Upgradient Field:
Dec -79 Dec -89
10(
I I
I i
Dec -99 Dec -09
MW -105
j
E RW -29 Observed
I-
-Model
Ili I '
Dec -19 Dec -29 Dec -39 Dec -49
1
Dec -79 Dec -89
Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
102
m
E
MO
10----
-
?
I.
1
Dec -79 Dec -89
Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
102

100
e�
Upgradient Fields: k -
1 4F -
Dec -79
MW -108
i
J r
■ MW -108
ObservedILL
Model J,
I �
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
103
100poll
I
I
T
Upgradient
f
ao
E
S
■
MW -105D Observed
10
z
—Model
i.
1
Dec -79 Dec -89 Dec -99 Dec -09
Dec -19 Dec -29
Dec -39 Dec -49
100
e�
Upgradient Fields: k -
1 4F -
Dec -79
MW -108
i
J r
■ MW -108
ObservedILL
Model J,
I �
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
103

E
MW -109
100
I
�l
E
m10 - ---.._.__.__ - ----- - - -----�� - - --. - i._.--- -�-�_-
t _
■ MW -109 Observed
Upgradient i
—Model
I
I
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
MW -110
100
Upgradient Fields:
500,201 -� ■ MW -110 Observed
■ I '
1 —Model
I
I
� I
� I
i
1
Dec -79
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
104

M W-111
100
I
Upgradient Fields:
j I t ■ MW -111 Observed
500,201 -
I
—Model
I
E
o j IL
FIT
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
M W -111-D
100
i
Upgradient Fields: ?I 11I},'r(} ■ MW -111D Obse rved -
500,201 rTTTT1T77T7T
—Model -
i-
E
III � ��, .I. •.I
I '
_ I
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
105

100
E
0 10
1
Dec -79
MW -201
100
Dec -89 Dec -99 Dec -09
lMW-202
Upgradient Field:
Dec -19 Dec -29 Dec -39 Dec -49
■ MW -202 Observed
�
- ' � i I
,
i
Upgradient
I
(
E
■ MW -201 Observed
j
'
—Model
,
' I
z
h�
100
Dec -89 Dec -99 Dec -09
lMW-202
Upgradient Field:
Dec -19 Dec -29 Dec -39 Dec -49
■ MW -202 Observed
106
—Model
(
E
'
10
z
h�
Dec
-79 Dec
-89 Dec
-99 Dec
-09 Dec
-19 Dec
-29 Dec
-39 Dec
-49
106

100
MW -203
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
107

Attachment 3.—Modeled and Observed Time Histories of NO3 through 2013
for Compliance Monitoring Wells
�:'

MW -13R and MW -13 (Compliance Wells)
100 .. ..
Upgradient Field:
42 IN MW -13R Observed
- ® MW -13 Observed
• —Model -'
E I.
10.._._.. _ —
O !
Z i ' f
i
1-1 1441
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
100 -
E 10
O
Z
1 -
Dec -79 Dec -89
MW -20 (Compliance Well)
Upgradient
I
-
® MW -20 Observed
Fields:
`..'
• ,
20, 21, 23
i
—Model
- -- - --i- -- ---..
IT-- *
-- _
..L_..
f4
r
_
Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
109

MW -22 and MW -22R Compliance Wells
100
Upgradient Field: + f
16 ■ MW-22RObserved
I
i. - rl �_ti _ - i . ' • l Observed
—Model
-
I i i
-10
z-
- I
- _ p -.
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
MW -41 (Compliance Well) jr
100 --. T T
T I
Upgradient Fields:
3 (now inactive)
,
i tip i
E
■ MW -41 Observed - -
`..�t. —
_ I Model
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
110

MW-42AR and MW -42A (Compliance Wells)
m
E
100
Epgr,
1 . 1 i i . 1 M, 1 i - . -1-4.._- — - i -- --+, __:--- _ , , , , - 'r'
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
111
100,--
--_
- --
--
.--- _
---- _
..-- -- --
'--
I
#
i
-
■ MW-42ARObserved
-
♦ MW -42A Observed
C
EI
—Model
zto
'
Upgradient Field
19
1�
Dec -79
Dec -89
Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
MW -44R and MW -44 Compliance Wells
m
E
100
Epgr,
1 . 1 i i . 1 M, 1 i - . -1-4.._- — - i -- --+, __:--- _ , , , , - 'r'
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
111

MW -45 Compliance Well
100
E
0 10
z
PB
k •.
.*4F
■ MW -45 Observed- -- -
,-I I —Model
iHII
i
1
Dec -79
Dec -89
100
E 10
Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
MW -46 (Compliance Well)
1 i ' — i —27 _ 4 � _._—}.. _ . _ ..-T�—
Dec-79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
112

100
m
10
1 I –
Dec -79
100 -
m
E
M 10
O
Z
1
Dec -79
1
p
— o
Dec -89
MW -47 (Compliance Well)
Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
MW -48 (Compliance Well)
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
113
_ _�..
Upgradient
-
■ I
I
r ' it
■
■ MW -48 Observed
®
—Model
Y
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
113

MW -49 (Compliance Well)
100
Upgradient Field:
74
■
i
■
li
10
_ __ _ _ ■
_.
_. _._
,_,___.
__. __
i
■
_I
-
® MW-490bserved
Model
I�
Dec
-79 Dec -89 Dec
-99 Dec
-09 Dec
-19 Dec -29 Dec -39 Dec
-49
MW -50 (Compliance Well)
100 ..
Upgradient "I -_ - - ■ MW -50 Observed
Fields: 75 I •-- - -
� —Model
m � ■ ■� � - ����".l _ IIS -
E 10
0 ■ - - -
Z 4 ■
l
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
114

MW -51R and MW -51 (Compliance Wells)
it
I iii �C.
100 -t vv $L— ! -~�f� �t�_ _. '_��_ _ UPgradient
I i'JF
0
z to --
It
Dec -79 Dec -89 Dec -99 De
100 -
E
0 10
1
Dec -79
MW -52R and MW -52 (Compliance Wells)
Upgradient
a
i
Field: 41
I.
® MW -52R Oberved _
l_
I
♦ MW -52 Observed
i
-_
M MW -51R Observed
_
,
♦ MW -51 Observed
_
Model
-39 Dec -49
09 Dec
-19 Dec -29 Dec
MW -52R and MW -52 (Compliance Wells)
Upgradient
I - i iii
i
Field: 41
I.
® MW -52R Oberved _
l_
I
♦ MW -52 Observed
—Model
I
I
E'
I
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
115

MW -53R and MW -53 (Compliance Wells)
100
- ..-
.,
.,.....
_
�►
*
�1 '
Upgradient Field:
Upgradient♦
I
' f
Field: 503
63
....
E 10
I i t
�
E
.T
10
■ MW -54R Observed
1
l
I
i
i
♦ MW -54 Observed
-
® MW -53R Observed
I
I ,
♦ MW -53 Observed
�
i
Model
Model
Dec -79 Dec -89 Dec
-99 Dec
-09 Dec
-19 Dec -29 Dec -39 Dec
-49
MW -54R and MW -54 (Compliance Wells)
100
- ..-
_
�►
*
�1 '
Upgradient♦
Field: 503
....
E 10
I �
�
■ MW -54R Observed
1
l
-
i
i
♦ MW -54 Observed
'
�
Model
Dec
-79 Dec
-89 Dec
-99 Dec
-09 Dec
-19 Dec -29 Dec -39 Dec
-49
116

MW -122 (Compliance Well)
100
Upgradient } - - ■ MW -122 Observed
fields: f _
520 —Model
I
E
10A
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
117

Attachment 4.—Modeled and Observed Time Histories of NO3 through 2013
for Other Active Monitoring Wells
118

TW -1R & TW -1
100 I Up71ds—
TW=10BSERVED
E10® TW -1R Observed
-
—Model
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
TW -2R & TW -2
100 Upgradient Fields: ---- -- -
16, 13 1
l
10
i ..
m
I- ■ TW -2R Observed T
■ TW -2 Observed -
—Model
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
119

100
E
M 10
0
z
E
m
0
z
1
Dec -79
TW -14R and TW -14
100
10
1
Dec -79
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
TW -16R and TW -16
Upgradient
'
I
i FieId:35
Upgradient Fields: 33, 37, 38
-
-
-
-
(Well may be cross -gradient) -
■ TW -16R Observed -
* {
�► ,
I
♦ TW-160bserved
—Model
■ TW -14R Observed
-
TW Observed
-
♦ -14
®
I
_Model
4--
100
10
1
Dec -79
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
TW -16R and TW -16
Upgradient
'
I
i FieId:35
�
■ TW -16R Observed -
* {
�► ,
I
♦ TW-160bserved
—Model
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
120

10
TW -18
1 +,_-- _ .. I I —I!_ __. --4 __ 1 4 — I – I - r
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
TW -25
100
Upgradient
1 _
Fields: 70
i
I
'
m 10
Z
-
-
-
- ■ TW -25 Observed
Model
i
.. f
1
Dec
-79 Dec -89 Dec
-99 Dec
-09 Dec
-19 Dec -29 Dec -39 Dec
-49
121

TW -30
100 ...
Upgradient Field: ■ TW -30 Observed --
I
l i I i
—Model
10
m i�il
o -
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
TW -30.1
100 ... ..
Upgradient Field:
602 ` 0 TW -30.1 Observed
t - E
—Model
10
IN --
{
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
122

TW -32
100 ...
Upgradient Field: 70 t
i i Ij ■ TW -32 Observed
—Model
' �..
E 4 �I
M
10
_
t 1 IN
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
TW -34
100 — IJ-
-- - - ■ TW-340bserved - -
Upgradient
Field: 70 —Model
. I I 111
i -
Z 10
�. .''. r.
I
I
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
123

100
m
E
z10
1
TW-45AR and TW -45A
_ Upgradient
Field: 47 -
■ TW-45AR Observed ---
-1 +-. - -
�- - ♦ TW -45A Observed
I —Model _
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
100
MW -100
I _
0000-100
WAL
Oil ...
I
® MW -100 Observed
—Model
Upgradient Field: 18
(cross gradient)
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
124

100
5
E
Z 10
1
Dec -79
MW -101
100
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
MW -101D
(
Upgradient -J--
i MW -101D Observed
I _-
' - —Model
I
1
� I I
Dec -79
�M
-
i 1tI
l
_ A -
4 444 44
Upgradient Field:
31
E
t
z10
T
I�
_
■ MW -101 Observed
i —Model
�I -
100
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
MW -101D
(
Upgradient -J--
i MW -101D Observed
I _-
' - —Model
I
1
� I I
Dec -79
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
125
E
E
z10
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
125

LTi 14YDt N
' I I
100
-
j �
E �t
0 10—
z F �
Upgradient Field: ■ MW -102 observed
38 —Model
:
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
100
MW -103
t
f
Upgradient
{ 1 ■ MW -103 OBSERVED -
Model
II
Dec -79
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
126

MW -104R and MW -104
100 .. ..
Upgradient Field: - _ ® MW -104R Observed
N�, ♦ MW -104 Observed
*Flow
—Model
I)
E10 --- - - �- -= - - - ------ ---�� -- - --- ----- . _ - -- . _. _.—�
:
14 -
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
MW -106
100
Upgradient R
Fields: 75, 71 4
1 I l i I
m �
.. 1 - - - - _..-- -- - _ - _ - ----- - - - i-
I
- ■ MW -106 OBSERVED
1
_ I —Model
i
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
127

10(
MW -112
1
Dec -79 Dec -89
Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
MW -113D
100 _.
Upgradient _ � �yl -
7 ■ MW -113D Oberved
I —Model
E
Dec-79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
128
m
E10
m
O
Z
i
1
Dec -79 Dec -89
Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
MW -113D
100 _.
Upgradient _ � �yl -
7 ■ MW -113D Oberved
I —Model
E
Dec-79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
128

MW -114
100 ..
Upgradient Fields: I ® MW-114Observed
None (Cross- °
gradient of —Model
I
I i
i
m I i
E
m10 -I - - - -- - -- ----- - ----- - -- - - -
O-
Z
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
MW -115
129
100
Upgradient Field:
-
E10
p
-
-
-
■ MW -115 Observed -
z
—Model
-� 11�
4J
P
Dec-79
Dec -89 Dec -99 Dec -09
Dec -19 Dec -29 Dec -39 Dec -49
129

MW -116
100
Upgradient {
Field: 62 � I ,
E
10,
i 1 ■ MW-1160bserved
I
—Model
or
1
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
100
E 10
M
0
z
MW -121R and MW -121
Upgradient Fields: I N MW -121R Observed
None C
(Upgradient of Field j ♦ MW -121 OBSERVED
600) ! —Model
i � I
dp
I � illi i
' I
L
{ 7A -
1 {')
1 -- ' 1 I
Dec -79
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
130

MW -122D
100 ....
Upgradient
Field: 520 0 MW 122D Observed -
Model i
� I
E10
� � I
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
MW -123D
K I,
100 UPgradient -- -- - - -- ,--� _.�+. -:----
f
E I�Ieloe
O 10 - I it TModel
MW-123DObserved
FLI --_-
Dec-79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
131

101
MW-124DR and MW -124D
Upgradient Fields:
26,28
��IIL it
■ MW-124DR Observed
- - ♦ MW -124D Observed _
.. �.' .� —Model
Dec -79 Dec -89 Dec -99
100
Upgradient
E
10 �-9
1
Dec -79 Dec -89 Dec -99
Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
uA iTi16 WRI
i l
® MW-125DO1served
—Model
ttj,_fl- fH'
' -
t.
I.
,
:-09 Dec -19 Dec -29 Dec -39 Dec -49
132

100
1
m
E
R 10
0
Z
MW -126D
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
MW -127
100
Upgradient Fields:
None ■ MW -127 Observed
(Upgradient of
Field 71) Model
E
I
10
z * i
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
133

100 ,
MW -204
Upgradient Fields: 1
None
( Cross/up-gradient of ■ MW -204 Obse ved
—Model
I I ;
E i
Z �
I I■ I -
,I I( I' I , ■ I i
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
MW -205
100
Upgradient Fields:
None ■ MW -205 Observed
(Cross/Up-gradient of —Model '
10
_ I -
E - I I■
m _
1 - - :-�'--- - - J- --- ------'�-'--'-�--- --- - -- _
-
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
134

-MITA IR
100
Up -Gradient
Field: 201 ® MW -206 Observed -
,
I —Model
10
f,
I '
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
MW -207
100 .. ..
Up -gradient Field: i 44 !
60
-10
I I I
I
E MW -207 Observed �
I-
i —Model
i
III � i
i II'
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
135

100
Dec -79
100
GP -1R and GP -1
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
GP -3R and GP -3
i
Up -Gradient I � .
--'-
-
E
E
O 10 - .- -- - ---- - I. �. i I __ 1 ■ GP -3R Observed
- { ♦ - ♦ GP -3 Observed
—Model
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
136
-
'
I it
■ GP -1 Observed
I
♦ GP -1 Observed i
—Model
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
GP -3R and GP -3
i
Up -Gradient I � .
--'-
-
E
E
O 10 - .- -- - ---- - I. �. i I __ 1 ■ GP -3R Observed
- { ♦ - ♦ GP -3 Observed
—Model
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
136

GP -5R and GP -5
100 _
Up -Gradient �
Field:8 f
i
1.
M I
i I t ■ GP -5R Observed
;. ♦ GP -5 Observed
—Model
r y
� I
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
GP -8R and GP -8
100
C
E
0 11
Z
1 4 .—
Dec -79
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
137

GP -911 and GP -9
100
Up -Gradient Field:
-. -- - ® GP -9R Observed
® GP -9 Observed
-� —Model
it
E ♦ �i
10, -- r- ,- - - - - _.. -- ----- -
o � 4
z i �
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
GP -10R
100
1
Dec -79
Up -Gradient
48
Field:
•
.:
■ GP -10R Observed
—Model
:
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
138

100
Up -Gradient
own j
E 10
M
z �
I.
GP -12R and GP -12
� I
■ GP -12R Observed
Dec -79 Dec -89 Dec -99 Dec -09
1
Dec -79
'♦ GP -12 OBSERVED -
t —Model
I l j I
Dec -19 Dec -29 Dec -39 Dec -49
GP -21R and GP -21
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
139
I
iI fur rj.._
rf
-
r
Up -Gradient
I
t
-
- ♦
-
■ GP -21R Observed -
'. i
♦'►
♦ GP -23 Observed
II
� Model
j t
-
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
139

GP -22R and GP -22
100
..
Up -Gradient
i
I i
10
- ■ GP -22R Observed -
+Y
♦ GP -22 Observed
lJ
Model
I
I
Dec -79 Dec -89 Dec
-99 Dec
-09 Dec
-19 Dec -29 Dec -39 Dec
-49
140

Attachment 5.—Modeled and Observed Time Histories of NO3 through 2013
for Active Surface Water Stations
141

100
100
1 i .. s. ----- —.L-- I' 1- 1 1--`---1 - -LP
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
m I�.
10 —
m i
O I
Z �
(
1 --
Dec-79 Dec -89
Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
142
E 10
— —
—
z
I�
100
1 i .. s. ----- —.L-- I' 1- 1 1--`---1 - -LP
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
m I�.
10 —
m i
O I
Z �
(
1 --
Dec-79 Dec -89
Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
142

SW -4
100 ... i ...
Contributing j E
I Fields: --ON IS- ■ - - .-- -- -
4,5,7,38-
I I
E 10
IIS i
■ SW -4 Observed
' —Model
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
SW -5
100
Contributing
Fields:
None "- i - ■ SW -5 Observed
—Model -
_-
I I
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
143

100
m
E
m 10
0
Z
1
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
I
Contributing
Fields:
28,29
SW -7
100
10 —
o�p
0
Z
1
SW -8
0 +--- L 11 1 0. �r-,-1 1 __; + I — - 4--
Dec-79
--J-Dec-79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
144

100
E 10 .I
0
0
z
1
Dec
100
1
Dec -79
SW -9
4
Contributing MINI m
Fields:
39, 40, 41, 100,
101, 102, 524 ■
I
I
■ SW -9 Observed
J I }(I —Model
i }11111' ...I_L.II il
I I I
79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
SW -16
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
145
I
Contributing
Fields:
45, 48, 49, 511,
, ;
512
I�I
i
�
it+illll
■ SW Observed
� i
■ SII
1.
-16
.
_ ■
■ -I
-
—Model '
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
145

100
E 10
m
O
Z
SW -20
Contributing
Fields:
None
■ SW -20 Observed
_Model
F
11h
1 _
Dec -79
100
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
SW -25
Contributing
Field: 62
r'
E 10
z■ SW -25 Observed
—Model
1 ., _ _..__._•___ '--�' ' .--_ice--. .____ � I �.i. �.
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
146

SW -26
100 .. ...
Contributing Field:
61
I
I
E 10
O � i
r
0 SW -26 Observed
Model j
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
10l
E 1(
O
z
SW -27
Contributing I -
Fields:
60,61
l i I i
F , I
I i
-� ® SW -27 Observed _ - _ i
IN
—Model
Dec -79
Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
147

SW -28
100 ..
i
E 10 ---- .. - - — ---- f _- �'.-� - ---- r-----
I
z Contributing Fields:
I All in South Half of Obse ved
Central Watershed Model
f
TI II
I Dili ; I I 1I i
Dec -79 Dec -89 Dec -99 Dec -09 Dec -19 Dec -29 Dec -39 Dec -49
148