NC0025453_Expanded Surface Water Discharge Evaluation_20240104

Expanded Surface
Water Discharge
Evaluation
Technical Memorandum
Sam’s Branch Water Reclamation Facility

Town of Clayton, North Carolina
January 4, 2024

This page intentionally left blank.

Town of Clayton | Expanded Surface Water Discharge Evaluation
Contents
i

Contents
1 Introduction ............................................................................................................................ 1
2 Receiving Waters Description ................................................................................................ 1
3 Water Quality Modeling Assessment ..................................................................................... 1
4 Model Results ........................................................................................................................ 2
5 Summary ............................................................................................................................... 7
Tables
Table 1. Modeled discharge effluent characteristics Sam’s Branch WRF .................................... 2
Table 2. Daily average DO model output near river kilometer 70 ................................................. 5
Table 3. Daily minimum DO model output near river kilometer 70................................................ 5
Figures
Figure 1. Neuse River Summer Dissolved Oxygen Concentrations with NRRRF at 75 MGD ...... 4
Figure 2. Neuse River Summer Dissolved Oxygen Concentrations with NRRRF at 75 and 90
MGD ................................................................................................................................ 6
Attachments
Attachment A – Neuse River Qual2K Water Quality Modeling Results

Town of Clayton | Expanded Surface Water Discharge Evaluation
Contents
ii

This page intentionally left blank.

Town of Clayton | Expanded Surface Water Discharge Evaluation
Introduction
1
1 Introduction
The Town of Clayton (Town) has been actively working to ensure wastewater capacity to meet
the Town’s immediate and long-term needs. The Sam’s Branch Water Reclamation Facility
(WRF) Phase 1 construction that provides 6 MGD in capacity is a first step that meets the
Town’s needs. While Phase 1 provides for immediate needs, the Town also must address short-
term and long-term capacity requirements for the service area. The Town has significant growth
(residential, commercial, and biopharmaceutical industry) and recent projections indicate Phase
2 (expansion to 10 MGD) preliminary engineering must begin immediately while the Sam’s
Branch WRF is still under construction.
This new information also emphasizes the need for additional long-range planning beyond the
current NPDES permit’s (Permit No. NC0025453) maximum discharge of 10 MGD. As part of
this long-term planning process, the Town is seeking speculative limits beyond the maximum
discharge limitation of 10 MGD in the Town’s current NPDES permit. Speculative limits will
provide the Town a reliable basis of planning for long-term wastewater capacity needs and
ensure appropriate space planning for the Sam’s Branch WRF site across all the current and
potential future drivers for wastewater treatment.
2 Receiving Waters Description
The Sam’s Branch WRF will discharge directly to the Neuse River pursuant to NPDES Permit
No. NC0025453 in the segment designated as Stream Index 27-(38.5), which is classified Water
Supply IV and Nutrient Sensitive Waters (WS-IV, NSW). In the Neuse River water quality model,
the river is modeled generally from Falls Lake to Goldsboro which includes multiple stream
segments. Predominantly all stream segments are classified as WS-IV or C and NSW due to
nutrient sensitivity in the Neuse River estuary. Certain segments in the model environment
downstream of the Sam’s Branch WRF are also classified as WS-IV Critical Area (CA) for
stream segments that include water intakes (i.e., for Johnston County, Smithfield, and
Goldsboro).
At the Sam’s Branch WRF discharge, the stream segment is not listed as impaired on the North
Carolina 2022 Integrated Report. In the model environment, there are stream segments
upstream listed as impaired; however, none are listed for impairment related to dissolved
oxygen (DO). No stream segments (within the model environment) are listed as impaired
downstream of the Sam’s Branch WRF except stream segment 27-(49.75), which is exceeding
criteria for copper.
3 Water Quality Modeling Assessment
The Neuse River QUAL2K water quality model was obtained from the Department of
Environmental Quality’s Division of Water Resources (DWR) to evaluate the possible expansion
of the Sam’s Branch WRF to 15 and 20 MGD. The model results are focused on DO to estimate
the impact of oxygen consuming parameters on the Neuse River from additional discharge of
highly treated municipal effluent. Model inputs and assumptions, including the 7-day average,
Town of Clayton | Expanded Surface Water Discharge Evaluation
Model Results
2
10-year recurrence interval low flow (7Q10) were not adjusted from the model provided by
DWR.
The effluent characteristics for the Sam’s Branch WRF were assumed to remain the same as
the current permit. Three effluent discharge flow regimes were modeled – 10 MGD which is the
maximum flow allowed in the current NPDES permit, 15 MGD to support the speculative limits
request, and 20 MGD for a sensitivity perspective. It is understood that the City of Raleigh is
also planning for an expansion of the Neuse River Resource Recovery Facility (NRRRF) to 90
MGD, which discharges to the Neuse River upstream of the Sam’s Branch WRF. For each of
the three flow scenarios for the Sam’s Branch WRF, additional model runs were included in this
effort for additional discharge at the NRRRF. The NRRRF’s current limit of 75 MGD was used
as was the expanded discharge at 90 MGD; discharge concentrations were held constant as
defined in the model, as provided by DWR, for each discharge condition. All other discharge
conditions were held constant as included in the current model.
It was assumed that the Town would obtain additional nitrogen allocation or credits to allow
discharge of the respective total nitrogen (TN) loads; therefore, it is assumed there is no impact
related to nutrients in the estuary.
The effluent concentration limits for Sam’s Branch WRF were the same for each flow regime
and are shown in Table 1.
Table 1. Modeled discharge effluent characteristics Sam’s Branch WRF
Modeled Effluent Limits Monthly Avg Daily Max Units
BOD, 5 day, 20° C (April 1- October 31) 5 7.5 mg/L
BOD, 5 day, 20° C (November 1- March 31) 10 15 mg/L
NH3-N (April 1- October 31) 1 3 mg/L
NH3-N (November 1- March 31) 2 6 mg/L
DO Daily Avg ≥6 mg/L
Total Phosphorus (mg/L) 2 (Quarterly Avg) mg/L
4 Model Results
Figure 1 provides a summary of the model results for the three flow scenarios for Sam’s Branch
WRF without considering any increase in flow at the NRRRF discharge (i.e., effluent flow of 75
MGD). The top panel in Figure 1 presents daily minimum model DO output for daily maximum
effluent limits for the summer 7Q10 low-flow condition (April 1- October 31). Model results from
this scenario were compared to the DWR daily minimum DO standard of 4 mg/L. The bottom
panel in Figure 1 presents daily average model DO output for monthly average effluent limits for
the summer 7Q10 low-flow condition (April 1- October 31). Model results from this scenario
were compared to the DWR daily average DO standard of 5 mg/L.
The modeling output indicates that DO is lower with an additional discharge of 5 MGD (i.e., from
10 MGD to 15 MGD) from the Sam’s Branch WRF and proportionately lower when the
discharge was increased by another 5 MGD (i.e., to 20 MGD). Daily average DO model output
decreases less than 0.1 mg/L (bottom panel) when increasing the effluent flow from 10 to 20
MGD, while the daily minimum DO model output decreases are slightly greater. However, this
Town of Clayton | Expanded Surface Water Discharge Evaluation
Model Results
3
decrease is only approximately 0.1 mg/L total while the flow is doubled from 10 MGD to 20
MGD (top panel). These maximum DO decreases associated with the increased flows occur
where the model output indicates the lowest overall DO levels occur (approximately at river
kilometer 70). At this location, daily average DO model output is approximately 5.4 mg/L at the
20 MGD effluent flow, which is above the daily average DO standard of 5 mg/L and slightly
higher than upstream baseline values (i.e., between the NRRRF and Sam’s Branch WRF
discharges). In addition, the daily minimum DO model output at this location is approximately
4.4 mg/L at the 20 MGD effluent flow, which is above the daily minimum DO standard of 4 mg/L.
The increases in Sam’s Branch WRF discharge flow does not change the pattern of DO
fluctuations from Falls Lake to Goldsboro.

Town of Clayton | Expanded Surface Water Discharge Evaluation
Model Results
4
Figure 1. Neuse River Summer Dissolved Oxygen Concentrations with NRRRF at 75 MGD
Town of Clayton | Expanded Surface Water Discharge Evaluation
Model Results
5
Figure 2 provides a summary of all model results for the three flow scenarios for Sam’s Branch
WRF while considering an increase in flow at the NRRRF to 90 MGD in addition to the current
flow of 75 MGD. The top panel in Figure 2 presents daily minimum DO model output for daily
maximum effluent limits for the summer 7Q10 low-flow condition (April 1- October 31). The
bottom panel in Figure 2 presents daily average DO model output for the monthly average
effluent limits for the summer 7Q10 low-flow condition (April 1- October 31).
The modeling output indicates that DO is incrementally lower with the increased discharges
from both the Sam’s Branch WRF and NRRRF. The change in daily average DO model output
as a result of the 15 MGD discharge by the Sam’s Branch WRF at current conditions (i.e.,
NRRRF at 75 MGD) compared to an increased discharge at NRRRF to 90 MGD results in less
than 0.1 mg/L decrease in DO where the model output indicates the lowest overall DO levels
occur (approximately at river kilometer 70). When the Sam’s Branch WRF flow is increased to
20 MGD the decrease remains less than 0.1 mg/L. At this location, daily average DO model
output are all above the daily average DO standard of 5 mg/L and slightly higher than upstream
baseline values (i.e., between the NRRRF and Sam’s Branch WRF discharges). In addition, the
daily minimum DO model output at this location is approximately 4.3 mg/L at the 20 MGD
effluent flow remaining above the daily minimum DO standard of 4 mg/L.
Table 2 and 3 present the daily average and daily minimum DO model output, respectively, for
the different Sam’s Branch WRF effluent discharge scenarios analyzed. Attachment A provides
all model results for the three Sam’s Branch WRF flow scenarios at the current flow for NRRRF
(75 MGD) and the same three Sam’s Branch WRF flow scenarios at a NRRRF discharge flow of
90 MGD.
Table 2. Daily average DO model output near river kilometer 70
Sam’s Branch WRF
Flow (MGD)
75 MGD NRRRF
Flow
90 MGD NRRRF
Flow
10 5.42 5.39
15 5.40 5.37
20 5.39 5.36
Table 3. Daily minimum DO model output near river kilometer 70
Sam’s Branch WRF
Flow (MGD)
75 MGD NRRRF
Flow
90 MGD NRRRF
Flow
10 4.55 4.42
15 4.50 4.37
20 4.44 4.31
Town of Clayton | Expanded Surface Water Discharge Evaluation
Model Results
6
Figure 2. Neuse River Summer Dissolved Oxygen Concentrations with NRRRF at 75 and 90 MGD
Town of Clayton | Expanded Surface Water Discharge Evaluation
Summary
7
5 Summary
The Town has significant growth (residential, commercial, and biopharmaceutical industry) and
recent projections indicate planning for capacity beyond the current NPDES permit flow
limitations is needed. Speculative limits for a 15 MGD discharge from the Sam’s Branch WRF
will provide the Town a reliable basis of planning for long-term wastewater capacity needs.
The Neuse River QUAL2K model was obtained from DWR to evaluate the possible expansion
of the Sam’s Branch WRF to 15 MGD in support of a speculative limits request. Model output
indicates that DO daily average values for all model scenarios remain above the daily average
DO standard of 5 mg/L and above the daily minimum DO standard of 4 mg/L including a
scenario of Sam’s Branch WRF increased to 20 MGD in conjunction with an expansion of the
NRRRF to 90 MGD. Model results support the development and issuance of speculative limits
for an expansion of the Sam’s Branch WRF to 15 MGD.

Town of Clayton | Expanded Surface Water Discharge Evaluation
Summary
8

This page intentionally left blank.
Town of Clayton | Expanded Surface Water Discharge Evaluation
Attachment A – Neuse River Qual2K Water Quality Modeling Results

A
Attachment A – Neuse River
Qual2K Water Quality
Modeling Results

Town of Clayton | Expanded Surface Water Discharge Evaluation
Attachment A – Neuse River Qual2K Water Quality Modeling Results

This page intentionally left blank.

4
5
6
7
8
170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0
DO

(
m
g
/
L
)
River Kilometer
Sa
m
s

B
r
a
n
c
h

W
R
F
Ne
u
s
e

R
i
v
e
r

W
W
T
P
Ce
n
t
r
a
l

J
o
h
n
s
t
o
n

C
o
u
n
t
y

R
e
g
i
o
n
a
l

W
W
T
F
Riv
e
r
M
i
l
l
s
Go
l
d
s
b
o
r
o

W
R
F
Sm
i
t
h

C
r
e
e
k

W
W
T
P
Summer Weekly Average Base Case (1A) - Clayton at 10 MGD
4
5
6
7
8
170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0
DO

(
m
g
/
L
)
River Kilometer
Sa
m
s

B
r
a
n
c
h

W
R
F
Ne
u
s
e

R
i
v
e
r

W
W
T
P
Ce
n
t
r
a
l

J
o
h
n
s
t
o
n

C
o
u
n
t
y

R
e
g
i
o
n
a
l

W
W
T
F
Riv
e
r
M
i
l
l
s
Go
l
d
s
b
o
r
o

W
R
F
Sm
i
t
h

C
r
e
e
k

W
W
T
P
Summer Monthly Average Base Case (2A) - Clayton at 10 MGD
DO (Min, Mean and Max) computed by Qual2K in the Neuse River Mainstem in Summer 2019
Neuse River RRF at 75 MGD
4
5
6
7
8
170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0
DO

(
m
g
/
L
)
River Kilometer
Sa
m
s

B
r
a
n
c
h

W
R
F
Ne
u
s
e

R
i
v
e
r

W
W
T
P
Ce
n
t
r
a
l

J
o
h
n
s
t
o
n

C
o
u
n
t
y

R
e
g
i
o
n
a
l

W
W
T
F
Riv
e
r
M
i
l
l
s
Go
l
d
s
b
o
r
o

W
R
F
Sm
i
t
h

C
r
e
e
k

W
W
T
P
Summer Weekly Average Scenario 1 (1W) - Clayton at 15 MGD
4
5
6
7
8
170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0
DO

(
m
g
/
L
)
River Kilometer
Sa
m
s

B
r
a
n
c
h

W
R
F
Ne
u
s
e

R
i
v
e
r

W
W
T
P
Ce
n
t
r
a
l

J
o
h
n
s
t
o
n

C
o
u
n
t
y

R
e
g
i
o
n
a
l

W
W
T
F
Riv
e
r
M
i
l
l
s
Go
l
d
s
b
o
r
o

W
R
F
Sm
i
t
h

C
r
e
e
k

W
W
T
P
Summer Monthly Average Scenario 1 (1M) - Clayton at 15 MGD
DO (Min, Mean and Max) computed by Qual2K in the Neuse River Mainstem in Summer 2019
Neuse River RRF at 75 MGD
4
5
6
7
8
170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0
DO

(
m
g
/
L
)
River Kilometer
Sa
m
s

B
r
a
n
c
h

W
R
F
Ne
u
s
e

R
i
v
e
r

W
W
T
P
Ce
n
t
r
a
l

J
o
h
n
s
t
o
n

C
o
u
n
t
y

R
e
g
i
o
n
a
l

W
W
T
F
Riv
e
r
M
i
l
l
s
Go
l
d
s
b
o
r
o

W
R
F
Sm
i
t
h

C
r
e
e
k

W
W
T
P
Summer Weekly Average Scenario 2 (2W) - Clayton at 20 MGD
4
5
6
7
8
170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0
DO

(
m
g
/
L
)
River Kilometer
Sa
m
s

B
r
a
n
c
h

W
R
F
Ne
u
s
e

R
i
v
e
r

W
W
T
P
Ce
n
t
r
a
l

J
o
h
n
s
t
o
n

C
o
u
n
t
y

R
e
g
i
o
n
a
l

W
W
T
F
Riv
e
r
M
i
l
l
s
Go
l
d
s
b
o
r
o

W
R
F
Sm
i
t
h

C
r
e
e
k

W
W
T
P
Summer Monthly Average Scenario 2 (2M) - Clayton at 20 MGD
DO (Min, Mean and Max) computed by Qual2K in the Neuse River Mainstem in Summer 2019
Neuse River RRF at 75 MGD
4
5
6
7
8
170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0
DO

(
m
g
/
L
)
River Kilometer
Sa
m
s

B
r
a
n
c
h

W
R
F
Ne
u
s
e

R
i
v
e
r

W
W
T
P
Ce
n
t
r
a
l

J
o
h
n
s
t
o
n

C
o
u
n
t
y

R
e
g
i
o
n
a
l

W
W
T
F
Riv
e
r
M
i
l
l
s
Go
l
d
s
b
o
r
o

W
R
F
Sm
i
t
h

C
r
e
e
k

W
W
T
P
Summer Weekly Average Scenario 5 (5W) - Clayton at 10 MGD
4
5
6
7
8
170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0
DO

(
m
g
/
L
)
River Kilometer
Sa
m
s

B
r
a
n
c
h

W
R
F
Ne
u
s
e

R
i
v
e
r

W
W
T
P
Ce
n
t
r
a
l

J
o
h
n
s
t
o
n

C
o
u
n
t
y

R
e
g
i
o
n
a
l

W
W
T
F
Riv
e
r
M
i
l
l
s
Go
l
d
s
b
o
r
o

W
R
F
Sm
i
t
h

C
r
e
e
k

W
W
T
P
Summer Monthly Average Scenario 5 (5M) - Clayton at 10 MGD
DO (Min, Mean and Max) computed by Qual2K in the Neuse River Mainstem in Summer 2019
Neuse River RRF at 90 MGD
4
5
6
7
8
170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0
DO

(
m
g
/
L
)
River Kilometer
Sa
m
s

B
r
a
n
c
h

W
R
F
Ne
u
s
e

R
i
v
e
r

W
W
T
P
Ce
n
t
r
a
l

J
o
h
n
s
t
o
n

C
o
u
n
t
y

R
e
g
i
o
n
a
l

W
W
T
F
Riv
e
r
M
i
l
l
s
Go
l
d
s
b
o
r
o

W
R
F
Sm
i
t
h

C
r
e
e
k

W
W
T
P
Summer Weekly Average Scenario 3 (3W) - Clayton at 15 MGD
4
5
6
7
8
170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0
DO

(
m
g
/
L
)
River Kilometer
Sa
m
s

B
r
a
n
c
h

W
R
F
Ne
u
s
e

R
i
v
e
r

W
W
T
P
Ce
n
t
r
a
l

J
o
h
n
s
t
o
n

C
o
u
n
t
y

R
e
g
i
o
n
a
l

W
W
T
F
Riv
e
r
M
i
l
l
s
Go
l
d
s
b
o
r
o

W
R
F
Sm
i
t
h

C
r
e
e
k

W
W
T
P
Summer Monthly Average Scenario 3 (3M) - Clayton at 15 MGD
DO (Min, Mean and Max) computed by Qual2K in the Neuse River Mainstem in Summer 2019
Neuse River RRF at 90 MGD
4
5
6
7
8
170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0
DO

(
m
g
/
L
)
River Kilometer
Sa
m
s

B
r
a
n
c
h

W
R
F
Ne
u
s
e

R
i
v
e
r

W
W
T
P
Ce
n
t
r
a
l

J
o
h
n
s
t
o
n

C
o
u
n
t
y

R
e
g
i
o
n
a
l

W
W
T
F
Riv
e
r
M
i
l
l
s
Go
l
d
s
b
o
r
o

W
R
F
Sm
i
t
h

C
r
e
e
k

W
W
T
P
Summer Weekly Average Scenario 4 (4W) - Clayton at 20 MGD
4
5
6
7
8
170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0
DO

(
m
g
/
L
)
River Kilometer
Sa
m
s

B
r
a
n
c
h

W
R
F
Ne
u
s
e

R
i
v
e
r

W
W
T
P
Ce
n
t
r
a
l

J
o
h
n
s
t
o
n

C
o
u
n
t
y

R
e
g
i
o
n
a
l

W
W
T
F
Riv
e
r
M
i
l
l
s
Go
l
d
s
b
o
r
o

W
R
F
Sm
i
t
h

C
r
e
e
k

W
W
T
P
Summer Monthly Average Scenario 4 (4M) - Clayton at 20 MGD
DO (Min, Mean and Max) computed by Qual2K in the Neuse River Mainstem in Summer 2019
Neuse River RRF at 90 MGD
4
5
6
7
170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0
Da
i
l
y

A
v
e
r
a
g
e

D
O

(
m
g
/
L
)
River Kilometer
Clayton at 10 MGD (1A)
Clayton at 15 MGD (1W)
Clayton at 20 MGD (2W)
Sa
m
s

B
r
a
n
c
h

W
R
F
Ne
u
s
e

R
i
v
e
r

W
W
T
P
Ce
n
t
r
a
l

J
o
h
n
s
t
o
n

C
o
u
n
t
y

R
e
g
i
o
n
a
l

W
W
T
F
Riv
e
r
M
i
l
l
s
Go
l
d
s
b
o
r
o

W
R
F
Sm
i
t
h

C
r
e
e
k

W
W
T
P
Summer Weekly Average Scenarios:
4
5
6
7
170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0
Da
i
l
y

A
v
e
r
a
g
e

D
O

(
m
g
/
L
)
River Kilometer
Clayton at 10 MGD (2A)
Clayton at 15 MGD (1M)
Clayton at 20 MGD (2M)
Summer Monthly Average Scenarios:
Daily Average DO computed by Qual2K in the Neuse River Mainstem in Summer 2019
Neuse River RRF at 75 MGD
4
5
6
7
170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0
Da
i
l
y

A
v
e
r
a
g
e

D
O

(
m
g
/
L
)
River Kilometer
Clayton at 10 MGD (5W)
Clayton at 15 MGD (3W)
Clayton at 20 MGD (4W)
Sa
m
s

B
r
a
n
c
h

W
R
F
Ne
u
s
e

R
i
v
e
r

W
W
T
P
Ce
n
t
r
a
l

J
o
h
n
s
t
o
n

C
o
u
n
t
y

R
e
g
i
o
n
a
l

W
W
T
F
Riv
e
r
M
i
l
l
s
Go
l
d
s
b
o
r
o

W
R
F
Sm
i
t
h

C
r
e
e
k

W
W
T
P
Summer Weekly Average Scenarios:
4
5
6
7
170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0
Da
i
l
y

A
v
e
r
a
g
e

D
O

(
m
g
/
L
)
River Kilometer
Clayton at 10 MGD (5M)
Clayton at 15 MGD (3M)
Clayton at 20 MGD (4M)
Summer Monthly Average Scenarios:
Daily Average DO computed by Qual2K in the Neuse River Mainstem in Summer 2019
Neuse River RRF at 90 MGD
4
5
6
7
170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0
Da
i
l
y

A
v
e
r
a
g
e

D
O

(
m
g
/
L
)
River Kilometer
Clayton at 10 MGD, Neuse River at 75 MGD (1A)
Clayton at 15 MGD, Neuse River at 75 MGD (1W)
Clayton at 20 MGD, Neuse River at 75 MGD (2W)
Clayton at 15 MGD, Neuse River at 90 MGD (3W)
Clayton at 20 MGD, Neuse River at 90 MGD (4W)
Clayton at 10 MGD, Neuse River at 90 MGD (5W)
Sa
m
s

B
r
a
n
c
h

W
R
F
Ne
u
s
e

R
i
v
e
r

W
W
T
P
Ce
n
t
r
a
l

J
o
h
n
s
t
o
n

C
o
u
n
t
y

R
e
g
i
o
n
a
l

W
W
T
F
Riv
e
r
M
i
l
l
s
Go
l
d
s
b
o
r
o

W
R
F
Sm
i
t
h

C
r
e
e
k

W
W
T
P
Summer Weekly Average Scenarios:
4
5
6
7
170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0
Da
i
l
y

A
v
e
r
a
g
e

D
O

(
m
g
/
L
)
River Kilometer
Clayton at 10 MGD, Neuse River at 75 MGD (2A)
Clayton at 15 MGD, Neuse River at 75 MGD (1M)
Clayton at 20 MGD, Neuse River at 75 MGD (2M)
Clayton at 15 MGD, Neuse River at 90 MGD (3M)
Clayton at 20 MGD, Neuse River at 90 MGD (4M)
Clayton at 10 MGD, Neuse River at 90 MGD (5M)
Summer Monthly Average Scenarios:
Daily Average DO computed by Qual2K in the Neuse River Mainstem in Summer 2019

This page intentionally left blank.

555 Fayetteville Street, Suite 900
Raleigh, NC 27601-3034
919.232.6600
NC License F0116
hdrinc.com
© 2024 HDR, Inc., all rights reserved