NC0086924_Request for Speculative Limits_20231201

GMA Apex,2205-A Candun Drive
North Carolina 27523
Telephone [phone]
PE Firm No. C-0854
The Groundwater Experts
RECEIVED
November 29, 2023 DECO 1 2023
Michael Montebello NCDEQIDWR1NPDES
NPDES Branch Chief
NPDES Complex Permitting Unit
1617 Mail Service Center
Raleigh, NC 27699-1617
RE: Request for Speculative Limits for Proposed Municipal Discharge
Mr. Montebello:
Bogue Banks Water Corporation (BBWC) is requesting that the NPDES Unit establish Speculative
Effluent Limits for effluent from a planned new Reverse Osmosis (RO) Water Treatment Plant
(WTP) near BBWC Well #11 (Figure 1). The RO WTP will be initially sized to produce 2 million
gallons per day (MGD) of finished water and will be expandable to 4 MGD. The discharge
would consist of concentrate wastewater from the RO WTP.
The proposed future discharge location for concentrate wastewater produced from the RO WTP
will be in a tidal channel of Bogue Sound near the Emerald Isle Boat Ramp, approximately 345
feet north of the shoreline near the Emerald Isle Boat Ramp (N 34.674325, W 77.06159).
According to the Carteret County GIS, this area of Bogue Sound is owned by the NC
Department of Environmental Quality and is listed under Parcel #539416836832000. The
discharge location was chosen based on site-specific flow and water quality data collected
during a one-week study at the proposed outfall location. The outfall location is shown on the
attached Figure 1. This location has access to property owned by the Town of Emerald Isle and
it has water depth and expected currents that would facilitate effective mixing of the RO
concentrate wastewater.
We contacted the U.S. Geological Survey to obtain low flow data for the proposed discharge
location. The USGS says that since the location is in Bogue Sound and is tidally influenced, they
can't provide any low flow data. The response from USGS is attached (email from J. Curtis
Weaver dated 11/28/23).
BBWC operates an existing RO WTP that discharges concentrate wastewater to a NPDES
permitted outfall (NPDES Permit NC0083089) in Bogue Sound near the Emerald Isle Bridge
L

Request for Speculative Effluent Limits
November 29, 2023
Page 2
(NC Highway 58). The proposed new RO WTP is needed to address growth and source water
quality issues. BBWC contact information is: Bogue Banks Water Corporation, 7412 Emerald
Drive, Emerald Isle, NC 28594; Mr. Seola Hill, 252-515-6353, [e-mail].
We have attached a copy of GMA's 2018 report titled "Future Reverse Osmosis Concentrate
Effluent Mixing Model Evaluation for the Bogue Banks Water Corporation"for your review and
use in preparing speculative effluent limits. Please let us know if you require additional
information.
Sincerely,
GMA �•• ^ � !+'
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Groundwater Management Associates, Inc.
NCPE Firm # C-0854
[e-mail]
Enclosures
Cc: Seola Hill, BBWC
Kristen Litzenberger, NPDES
Derek Denard, NPDES

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WELL 11 * PROPOSED BBWC WTP OUTFALL
FILE. DRAWINGS/24312/ STUDY AREA DATE. 6/19/2018
Figure_1_Study_Area
FUTURE BBWC RO WASTEWATER MIXING STUDY,
PROJECT NO. 24312 FIGURE 1
CARTERET COUNTY, NORTH CAROLINA

From: Weaver.John C
To: John Wise
Cc: Bill Lvke;Bodkin,Lee J;Walters,Douglas A;McClenney.Bryce J;Algerdn.Klaus P;Weaver.John C
Subject: USGS response concerning...RE: [EXTERNAL]Bogue Sound streamflow estimates
Date: Tuesday,November 28,2023 11:58:16 AM
Good morning, Mr. Wise:
Your suspicions are correct. The USGS does not provide estimates of low-flow discharges for stream
locations that are known or suspected of being tidally influenced.
r formally your r and Mo e f o a g f or records
The USGS South Atlantic Water Science Center (Raleigh office) currently refrains from providing (or
updating previously determined) low-flow estimates for streams known or suspected of being tidally
affected or influenced as shown on this map, https://pubs.usgs.gov/wsp/2221/plate-1.pdf.There are
currently no techniques that allow for quantifying the effects of tides on low flows. Concerns that
tides may possibly reduce low-flow discharges (that is, relative to low-flow estimates for the same
stream not tidally-affected) lead to speculation that any such estimates for these streams may be
too high. Given the "back-n-forth"flow dynamics associated with tidal effects, attempting to
determine low-flow characteristics based on the assumption of uni-directional flow characteristics is
not considered meaningful.
The requestor will should NCDEQ for further guidance if the stream at the point of interest is known
to be tidally influenced.
Thank you.
Curtis Weaver
J. Curtis Weaver, PE
Assistant Director for Data - North Carolina
USGS South Atlantic Water Science Center(GA-SC-NC).
3916 Sunset Ridge Road I Raleigh, NC 27607
Mobile: [phone]
From: Bodkin, Lee J <[e-mail]>
Sent:Tuesday, November 28, 2023 11:29 AM
To: Weaver,John C<[e-mail]>; McClenney, Bryce J <[e-mail]>
Cc: Bill Lyke<[e-mail]>;John Wise<[e-mail]>; Walters, Douglas A
<dwa lters @ usgs.gov>
Subject: Re: [EXTERNAL] Bogue Sound streamflow estimates

Hello John-
Apologies for missing your call I'm out of the office today.
I am forwarding your email on to the NC Data chief(John (Curtis)Weaver), and the acting
Raleigh Field office chief(Bryce McClenney)who wilt be able to provide you with more
information.Thank you.
Lee
******************************************************
Lee Bodkin
USGS -South Atlantic Water Science Center
Hydrologist - Water Quality Specialist
3916 Sunset Ridge Rd.
Raleigh, NC 27607
[phone] - Office
[phone] - Mobile
[phone] - Fax
Jittps://www.usgs.govicentersisa-water
https://www2.usgs.gov/water/southatlantic/
******************************************************
From:John Wise<JohnPgma-nc.com>
Sent:Tuesday, November 28, 2023 11:15 AM
To: Bodkin, Lee J <Ijbodkin aPusgs.gov>
Cc: Bill Lyke<BillPgma-nc.com>
Subject: [EXTERNAL] Bogue Sound streamflow estimates
This email has been received from outside of DOI - Use caution before clicking on links,
opening attachments, or responding.

Mr. Bodkin,
I left you a voice message earlier then found your email address. We are working for
Bogue Banks Water Corporation (BBWC) in Emerald Isle NC to determine if they will
be able to get an NPDES permit for a new wastewater discharge from a water
treatment plant. The NPDES Unit will evaluate whether a proposed municipal
discharge is considered allowable if BBWC initiates this review by submitting a letter
request for Speculative Effluent Limits to the NPDES Unit. The NPDES Unit says we
must obtain streamflow estimates for the proposed discharge location to ensure that
the receiving stream is not subject to zero flow restrictions. They advise in their
guidance that Low flow data (specifically, drainage area, summer and winter 7Q10,
average flow and 30Q2 flow statistics) can be obtained from the U.S. Geological
Survey and that the low flow data must be submitted with the speculative limits
request letter.
Is this somethingyou canprovide? The proposed location of the discharge is in a
p p g
tidal channel of Bogue Sound near the Emerald Isle Boat Ramp, approximately 345
feet north of the shoreline (N 34.674325, W 77.06159) See the attached Figure 1.
9
We suspect USGS can't give flow data since the Sound is tidally influenced. If that's
the case, a message back from you saying so would be helpful.
Thanks,
John J. Wise, P.E.
Principal Civil/Environmental Engineer
Groundwater Management Associates, Inc.
2205-A Candun Drive
Apex, NC 27523
919-363-6310
NC PE # 15056
PE Firm # C-0854

Future Reverse Osmosis Concentrate Effluent RECEIVED
Mixing Model Evaluation ] 2023
for the Bogue Banks Water Corporation DEC 0
NCDEQ/DWR/NPDES
GMA Project Number: 24312
PREPARED FOR:
Mr. Seola Hill
Bogue Banks Water Corporation
7412 Emerald Dr
Emerald Isle, NC 28594
PREPARED BY:
Groundwater Management Associates, Inc.
4300 Sapphire Court, Suite 100
Greenville, North Carolina 27834
Telephone: [phone] ,``.'wosit A"����'�•,
Facsimile: [phone] .o,� �.. .. R ,
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July 16, 2018

Table of Contents
1.0 INTRODUCTION 1
2.0 CORMIX DESCRIPTION 2
3.0 STUDY SITE AND AMBIENT CONDITIONS 2
3.1 METHODS 3
3.1.1 Current Velocity and Direction 3
3.1.2 Channel Geometry 4
3.1.3 Water Quality Sampling 4
3.1.4 Benthic Invertebrates 5
3.1.5 Sediment Grain Size Analysis 5
3.2 FLOW STUDY RESULTS 5
3.3 WATER QUALITY 6
3.4 BENTHIC INVERTEBRATES 6
3.5 SEDIMENT GRAIN SIZE ANALYSIS 7
4.0 CRITERIA FOR OUTFALL DESIGN AND EFFLUENT WATER CHEMISTRY 7
5.0 CORMIX SIMULATIONS FOR THE PROPOSED DISCHARGE 8
5.1 DISCHARGE DESIGN VARIABLES AND SINGLE-PORT DISCHARGE INVESTIGATION 8
5.2 OPTIMIZED SIMULATION OF A SINGLE-PORT SIMULATION 10
5.3 CORMIX SENSITIVITY ANALYSIS 10
5.4 SIMULATIONS OF VARIED DISCHARGE FLOW RATE 12
5.5 SIMULATIONS OF VARIED SOURCE WATER SALINITY 13
6.0 CONCLUSIONS AND RECOMMENDATIONS 13
7.0 REPORT CERTIFICATION 14
8.0 REFERENCES 14
List of Figures
1. Study Area
2. Example of CORMIX Flow Classification Chart
3. Staff Gauge and Channel Cross-Section Locations
4. Progressive Vector Plot and Rose Diagram of Currents at the Proposed Discharge Location
5. Optimized Diffuser-Orientation
6. Plan View of Plume Geometry using an Optimized Multi-Port Diffuser
7. Concentration Excess versus Distance using an Optimized Multi-Port Diffuser
8. Dilution versus Distance using an Optimized Multi-Port Diffuser

List of Tables
1. Summary of Monitoring and Sample Site Locations
2. Field Water-Quality Observations and Analytical Results
3. Summary of Grain Size Analyses
4. Discharge Variables for the Proposed RO Outfall
5. Effluent Variables for the Proposed RO Outfall
6. Ambient Variables at the Proposed RO Outfall Location
7. CORMIX Simulation Variables
8. CORMIX Simulation Results
9. Multi-port Simulation Variables for the Proposed BBWC RO Discharge
Appendices
I. Photographs
II. Meteorological Data from the KNJM Weather Station
III. Tidal Predictions from NOAA tidal station TEC2837 at Bogue Inlet
IV. Laboratory Analytical Reports
V. Benthic Macroinvertebrate Analyses
VI. Grain Size Analyses
VII. DWQ Mixing Zone Rule
VIII. CORMIX Output Files for the Optimized Single Port and Multi-Port Simulations
GMA

RO Effluent Mixing Model Evaluation
Bogue Banks Water Corporation
1.0 INTRODUCTION
Bogue Banks Water Corporation (BBWC) plans to construct a new Reverse Osmosis (RO) Water
Treatment Plant (WTP) near BBWC Well #11 (Figure 1). The RO WTP will be initially sized to
produce 2 million gallons per day (MGD) of finished water and will be expandable to 4 MGD.
Discharge of concentrate wastewater, or reject, produced from the RO WTP will require a
National Pollutant Discharge Elimination System (NPDES) permit from the North Carolina
Department of Environmental Quality (NCDEQ).
BBWC operates an existing RO plant that discharges concentrate wastewater to a NPDES
permitted outfall in the Bogue Sound near the Emerald Isle Bridge. In 2007, GMA assisted
BBWC and their engineer at the time, The Wooten Company, with an evaluation of mixing
characteristics of the chosen discharge site and with establishing a regulatory mixing zone
around the outfall. Because the Bogue Sound is tidal, establishing a mixing zone as part of the
NPDES permit was based on a mixing and dispersal model, not on the 7Q10 low flow of the
receiving water body. The surface water mixing modeling performed by GMA guided the initial
site selection process, evaluated a multi-port diffuser design, and supported permitting.
Characteristics of the future RO reject are generally anticipated to be similar to the effluent
from the current RO plant. Therefore, the new NPDES permit from the NCDEQ will again
require establishing a regulatory mixing zone around the new outfall.
Groundwater Management Associates, Inc. (GMA) was contracted by the BBWC to provide
CORMIX (Cornell Mixing Zone Expert System) simulations for the purpose of evaluating mixing
characteristics at the proposed discharge site and to support establishment of a regulatory
mixing zone as part of a future NPDES permit application. CORMIX is an expert rule-based
system for the analysis, prediction, and design of pollutant discharges into several types of
water bodies (Doneker and Jirka, 2012). This report summarizes the results and implications of
a series of surface water mixing simulations performed by GMA using the CORMIX (Version 10.0
GT) modeling program. Simulations were based on ambient flow and water-quality data
collected at the location of the proposed RO WTP outfall during a short-duration field study
conducted by GMA (Figure 1).
GMA does not attempt in this report to provide a full-scale presentation of all the simulations
performed and their implications. Our goal is to provide pertinent information to support the
permit application and design for the discharge to the Bogue Sound. BBWC will submit an
application and supporting documentation for the new NPDES permit at a later time.
Specifically, the purpose of this report is to:
1) Evaluate near-field mixing characteristics of the proposed discharge location,
2) Evaluate hydrologic implications for various diffuser design options,
3) Address regulatory concerns about the mixing characteristics of the proposed surface
water discharge, and
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RO Effluent Mixing Model Evaluation
Bogue Banks Water Corporation
4) Define the mixing zone and the predicted water-quality characteristics at the mixing
zone boundaries.
Diffuser details and suggested orientations discussed in this report are for mixing modeling
purposes only. Actual design of the facilities to be used for effluent discharge on this project
are outside of the scope of this study and will be performed at a later date by a NC licensed
Professional Engineer.
2.0 CORMIX DESCRIPTION
CORMIX is a rule-based expert system that models the discharge of several types of effluent
into various water bodies and covers a majority of common discharge and environmental
conditions (Doneker and Jirka, 2012). The expert rule-based system requires the user to input
data about the nature of the ambient conditions, the effluent, and the discharge configuration
(diffuser design, etc.). These input parameters are run through a series of"If" (conditions) and
"Then" (conclusions/hypothesis) logical steps to classify how the effluent-plume will behave.
Figure 2 is an example of a flow classification chart for a multi-port discharge that illustrates
some of the logical steps CORMIX utilizes to determine the flow classification. Once the flow is
classified, CORMIX utilizes integral, length-scale, and passive-diffusion approaches to simulate
the hydrodynamics of different regions of the effluent plume (Doneker and Jirka, 2012). In
essence, CORMIX uses different logical and mathematical approaches to describe different
areas of the plume once the flow has been classified.
CORMIX simulates the hydrodynamics of both near-field and far-field mixing zones. The near-
field is the region of a receiving water where the initial jet characteristics of momentum flux,
buoyancy, and outfall geometry control mixing of the effluent (Doneker and Jirka, 2012). Near-
field mixing is more predictable, usually generates the greatest amount of mixing, and occurs
before the plume interacts with any boundaries. Boundaries could include: a shoreline, the
bottom of a water body, the water surface, etc. The first boundary encountered represents the
end of the near-field region. The diffuser or port design, and its orientation to the ambient
current, are the dominant controls on the amount of mixing that occurs in the near-field region.
The far-field region occurs after boundary interaction, and control of mixing is dominated by
ambient conditions and passive diffusion. In steady, non-reversing flows, CORMIX predicts
mixing and plume characteristic in the far-field region until these predictions become less
reliable, then the simulation is terminated. In unsteady tidal reversing flows, such as those
seen in the Bogue Sound, simulations include re-entrainment effects on plume behavior and are
terminated at the point of tidal reversal.
3.0 STUDY SITE AND AMBIENT CONDITIONS
The proposed future discharge site is located in a tidal channel of Bogue Sound near the
Emerald Isle Boat Ramp, approximately 345 feet north of the shoreline from Parcel
#539420915466000 (Emerald Isle Parks and Rec). According to the Carteret County GIS, this
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RD Effluent Mixing Model Evaluation
Bogue Banks Water Corporation
area of Bogue Sound is owned by the NC Department of Environmental Quality and is listed
under Parcel #539416836832000.
Ambient conditions for the CORMIX simulations were based on site-specific flow and water-
quality data collected during a one-week study at the proposed outfall location (the study site),
(N 34.674325, W 77.06159, Figure 1, Table 1). This location was selected because it has
access to property owned by the Town of Emerald Isle and it has water depth and expected
currents that would facilitate effective mixing of the RO concentrate wastewater. Other areas
near Well #11 (e.g. Archer's Creek) are expected to be too shallow and/or have inadequate
flow to facilitate mixing.
Specific tasks related to establishing ambient conditions for the proposed discharge location
were completed by GMA as follows:
1) Studied flow dynamics at the proposed site — current, tides, and wind effects
2) Measured channel geometry at and near the existing discharge location
3) Measured temperature, dissolved oxygen, conductivity, salinity, pH, and oxidation
reduction potential (ORP) in the vicinity of the proposed discharge
4) Collected grab water samples for water-quality analyses
5) Collected benthic invertebrate samples and sediment cores
Data analyses from this field evaluation provided the needed site-specific background data for a
CORMIX mixing model to simulate a discharge at the proposed WTP outfall location.
3.1 METHODS
3.1.1 Current Velocity and Direction
Water current data were collected with a Falmouth Scientific, Inc., 3-Dimensional Acoustic
Current Meter (ACM-PLUS) (Appendix I). This instrument is lightweight, compact, and is
capable of collecting and storing highly accurate 2- or 3-dimensional velocity measurements,
even in low flow conditions. The ACM-PLUS measures current velocity in 3 dimensions using
four acoustic transducers mounted on fingers in an orthogonal configuration. Current velocity is
calculated using a phase-shift acoustic transit-time measurement technique. Accuracy of
velocity measurement is +/-2%. The inclusion of an internal 3-axis magnetometer and 2-axis
tilt sensor allow the instrument to collect true current direction without needing to know the
specific orientation of the meter during deployment. Accuracy of the direction and tilt are +/-2°
and 0.5°, respectively.
The ACM-PLUS instrument was deployed from 11:04 am on October 20, 2017, until 10:20 am
on October 27, 2017. The meter was set to power up every 15 minutes and measure
instantaneous currents for a period of 2 minutes. At the end of the 2 minute interval, the unit
would record the average current velocity and direction measured during the interval, and
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RO Effluent Mixing Model Evaluation
Bogue Banks Water Corporation
would then enter into a standby mode to conserve battery power. This setup provided 4
measurements of the current velocity and direction every hour.
To evaluate the dominant forcing agents of currents in this area, GMA obtained wind
speed/direction and precipitation amounts from the North Carolina State Climate Office for the
nearest weather station (KNJM located at Marine Corps Auxiliary Field Bogue) (Figure 1,
Appendix II). Tidal variations were based on predicted tidal ranges from the subordinate NOAA
tidal station (Station ID TEC2837), which is located in Bogue Inlet approximately 5.6 miles west
of the proposed discharge site (N 34.650000°, W 77.100000°, Appendix III). Tidal predictions
at this station are referenced to the NOAA station at Beaufort, NC (#8656483, N 34.720000°, W
76.670000°). Wind speed, wind direction, and precipitation information were obtained from the
weather station KNJM- Bogue Field Marine Corps Auxiliary Landing Field (N 34.690500°, W
77.02967°).
3.1.2 Channel Geometry
GMA measured water depth along three channel profiles extending from the northern shore of
Bogue Banks near the Emerald Isle boat ramp to Long Marsh, located approximately 775 feet to
the north (Figure 3). GMA recorded depths using a Lowrance HDS-7 chartplotter with
TotalScan sonar transducer mounted to the bottom of the boat. Depths recorded using the
sonar transducer were converted to actual water depths by establishing the relationship
between transducer based depth values and water depth as measured by hand using a
telescoping stadia rod.
In addition, GMA installed a temporary staff gauge on a piling located on the southern tip of
Long Marsh (Figure 3), and we correlated the staff gauge readings to water depths measured at
the flow meter. BBWC staff read the staff gauge periodically throughout the study period in
order to provide supplemental
water-depth data.
3.1.3 Water Quality Sampling
GMA measured water-quality parameters in the immediate vicinity of the flow station on
October 20 during near high tide conditions and near low tide conditions (Table 2).
Temperature, dissolved oxygen (DO), conductivity, salinity, pH, and oxidation reduction
potential (ORP) were measured using a YSI Professional Plus water-quality meter. In addition,
GMA collected grab samples of water near the proposed outfall location near high tide and near
low tide (at approximately 2.5 feet below the surface) for analysis of total dissolved solids,
chloride, total phosphorus, total nitrogen, total Kjeldahl nitrogen, and turbidity. Water samples
were kept on ice and transferred to Environmental Chemists, Inc., following chain-of-custody
protocol. The sampling program was designed to provide a "snap-shot"of existing conditions
at the proposed future discharge outfall.
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RO Effluent Mixing Model Evaluation
Bogue Banks Water Corporation
3.1.4 Benthic Invertebrates
On October 20, 2017, GMA collected six benthic macroinvertebrate grab samples within 110
feet of the proposed outfall using a 6"x 7.5"x 3"deep LaMotte sampling dredge (Figure 3).
Sample depths varied by core and are listed in Table 1. GMA sieved each sample in the field
using a 0.5 mm mesh screen, and we immediately placed the samples in 1 L HDPE bottles
containing formalin preservative. GMA took care to ensure sufficient preservative was used for
each sample and that all samples were properly labeled. Samples were then shipped to
EnviroScience, Inc. of Stow, OH for macroinvertebrate identification and analysis. Field water-
' quality measurements were provided to the aquatic macroinvertebrate biologist for
interpretation in relation to the macrofaunal species identified.
P P
3.1.5 Sediment Grain Size Analysis
GMA collected five sediment cores within 110 feet of the proposed outfall using a 6"x 7.5"x 3"
deep LaMotte sampling dredge on October 20, 2017 (Figure 3). A full 3 inch deep sample was
recovered at each location (Table 1). Samples were placed in a cooler and transported to
Terracon Consultants, Inc. of Winterville, NC for grain size analyses using sieve and hydrometer
methods.
3.2 FLOW STUDY RESULTS
Observed water depth at the proposed outfall location ranged from approximately 4.2 feet at
low tide to 6.3 feet at high tide. Flow direction and velocity measurements indicate that slack
tide at the site occurs between 1.75 and 3.5 hours after tidal reversal at the Bogue Inlet
monitoring station, with an average lag of approximately 3 hours. The period of current
reversal due to tides is on the order of 12.45 hours for the time when the current meter was
deployed. Wind speeds during the study period varied from 0 to 25 miles per hour (mph) and
averaged 5.9 mph during the deployment of the current meter.
Current direction at the site generally alternated between southeast during rising tides and
northwest during falling tides, which generally aligns with the local shoreline orientation and
illustrates the tidal nature of flow (Figure 4). During the study period, rising current speeds
averaged 0.58 +/- 0.24 feet per second, and falling current speeds averaged 0.26 +/- 0.11 feet
per second. The maximum observed current speed was 1.06 feet per second. The average
current velocity at 1-hour after slack tide, which represents flow velocity during the period
where the effects of re-entrainment of discharge from the previous tidal cycle are expected to
be greatest, was 0.56 +/-0.23 feet per second.
A progressive vector plot of collected data demonstrates the tidal nature of flow at the site
(Figure 4). This plot simulates a Lagrangian point of view by simply adding the vector
associated with each current measurement to the previous vector measured at the site, thus
providing an estimate of flow direction and distance traveled. By assuming that the currents
remained at the same speed and orientation between scans (15 minutes), we can estimate the
net distance that water traveled past the current meter during the study period. Such an
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RO Effluent Mixing Model Evaluation
Bogue Banks Water Corporation
estimate assumes that current speed and direction do not change beyond the measurement
point and that there are no physical limitations to flow orientation, which is certainly not the
case. Despite these assumptions, this plot is useful for visualizing overall flow patterns. As is
apparent from the progressive vector plot of data from this site, flow near the proposed BBWC
discharge location is tidal with slightly higher velocity flows occurring during the rising tide
when flow is directed to the east-southeast.
3.3 WATER QUALITY
Field water-quality measurements and the analytical results from grab samples taken at the site
summarized in Table 2. The laboratory October 20, 2017, are reports are included in
Appendix IV.
Water temperatures measured at the site ranged from 19.7 to 21.4° C. Large temperature
iff rences with depth were not noted. Specific conductance at the site was slightly lower with
differences p 9 Y
P
depth and may indicate groundwater discharge along the channel bottom. Salinity, as
calculated from measured chloride concentrations, ranged from 23.31 to 25.65 ppt. Salinity
measured during GMA's field study was slightly lower than historical salinity measurements from
the closest known NCDEQ water quality monitoring station in the Bogue Sound (Station
P9580000). This station is located more than 9 miles to the east-northeast at channel marker
G15 near Salter Path (Figure 1). Ambient DO concentrations measured during this study
ranged from 7.28 to 8.48 mg/L, levels not typically stressful to marine macrofauna common to
the site. Data on pH indicated that the Bogue Sound was neutral to slightly basic. ORP,
conductivity, and pH measurements were all values that would be expected in tidal, estuarine
settings (Appendix V), and these values were within the range of historic values from
monitoring station P9580000.
Laboratory analyses of water samples collected by GMA on October 20, 2017, were intended to
provide confirmation of ambient conditions for key monitoring parameters. The Total Dissolved
Solids (TDS) and chloride analyses confirm the brackish conditions as measured in the field.
Ammonia nitrogen was detected at a concentration of 0.3 mg/L in the grab sample from the
flow station collected near high tide, but was not detected in the sample collected near low tide.
3.4 BENTHIC INVERTEBRATES
EnviroScience, Inc., identified twelve macroinvertebrate species from the samples collected
during the field study (Appendix V). These organisms consisted predominantly of marine
polychaete worms (n=8). Seed shrimp (Ostracoda), a single dwarf clam (Mulinia lateralis), and
two types of marine amphipods (Ampelisca sp. and Leptocheirus sp.) were also identified from
the samples collected at the site. All organisms are typical of marine and estuarine habitats in
p
NC (Hymel, 2009). The Shannon-Wiener Diversity Index (H') is a widely used calculation for
determining biodiversity that accounts for both the total number of species found at a site and
the relative abundance of each species within the sample. Based on genus-level classification,
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RO Effluent Mixing Model Evaluation
Bogue Banks Water Corporation
H' was calculated to be 1.29 for the site, which is considered low for benthic macroinvertebrate
communities but is similar to estimates from comparable settings in NC (Hymel, 2009).
3.5 SEDIMENT GRAIN SIZE ANALYSIS
Sediments collected at the site consisted of gray, fine sands with silt and clay. Results of the
five grain size analyses from the vicinity of the proposed outfall are presented in Table 3.
Original particle size distribution reports provided by Terracon are provided in Appendix VI. The
predominance (>85%) of fine grained sand particles at the site indicates the system has
enough energy to winnow out the finer particle fractions. The major energy source in this
location is tidal currents.
4.0 CRITERIA FOR OUTFALL DESIGN & EFFLUENT WATER CHEMISTRY
Careful selection of the outfall position and design characteristics can maximize the initial
dilution and minimize the environmental impact of the discharge. The regulatory area around a
port or diffuser, where the initial dilution of an effluent is allowed to occur, is referred to as a
mixing zone. The North Carolina Division of Water Resources, Water Quality Permitting Division
(NCDWR-WQP) (formerly the Division of Water Quality (NCDWQ)) defines a mixing zone as"an
area downstream of a discharge point where the effluent is diluted by the receiving water and
within which certain water-quality standards that would otherwise be applicable may be
exceeded" (NCDWQ, 1999). The NCDWQ mixing zone rule is included in Appendix VII.
GMA reviewed information available on the NCDWR website (NCDWR, 2017), concerning
classification of the Bogue Sound and the regulations concerning the water quality of the water
body. The Bogue Sound is classified as a Class SA water body, which means that water quality
should meet the sanitary and bacteriological standards suitable for commercial shellfish culture
and all types of recreational use. By definition, Class SA waters are also designated as High
Quality Waters (HQW) by the NCDWQ. Regulations affecting Class SA waters are available in
North Carolina Administrative Code 15A NCAC 02B Rule .0221 (NCDENR, 2007).
The Bogue Banks Water Corporation provided anticipated effluent water chemistry based upon
2017 historical monitoring of their existing RO plant discharge. Based upon these records,
concentrations of ammonia nitrogen have historically been the greatest relative to the 2B
standard, and therefore require the greatest dilution in order to meet the regulatory water-
quality criterion. GMA has modeled the dilution of ammonia nitrogen in CORMIX simulations as
the primary mixing constituent. GMA has set a conservative goal of modeling an outfall that
dilutes effluent concentrations to existing water-quality standards within a circular mixing zone
10 meters in diameter around the outfall.
To determine whether the proposed site will provide adequate mixing under the worst-case
scenario conditions, and to ensure that the effluent diffuser would adequately mix future
discharge volumes, GMA modeled a projected future RO reject volume of 1 MGD at a
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RO Effluent Mixing Model Evaluation
Bogue Banks Water Corporation
concentration of 5 mg/L of ammonia nitrogen. This represents the predicted future effluent
volume at the expanded plant capacity of 4.0 MGD of finished water. Initially, the proposed RO
plant will only produce 2.0 MGD of finished water with a reject volume of 0.5 MGD. The
greatest concentration of ammonia nitrogen measured in the existing RO plant effluent during
2017 was 4.48 mg/L, less than the concentration used for all CORMIX simulations.
5.0 CORMIX SIMULATIONS FOR THE PROPOSED DISCHARGE
GMA performed an iterative series of CORMIX simulations to evaluate the effects of potential
discharge configurations (i.e. diffuser design) on effluent mixing characteristics under a worst-
case scenario using the future 1.0 MGD reject volume. Simulations were based on a
conservatively assumed background concentration of 0 mg/L of ammonia nitrogen in the
ambient environment. Detailed information on effluent discharge density, ambient density,
depth at the proposed outfall location, diffuser configuration, and river current velocities served
as input for the CORMIX model (Tables 4-6).
GMA used unsteady tidal reversal analyses available in CORMIX to simulate the effects of tidal
flow on mixing at the proposed outfall location. CORMIX can predict the buildup of effluent that
occurs in tidal regimes when the current is reversed. To evaluate mixing at the site under
worst case conditions, GMA simulated the time of minimum dilution. The time of minimum
dilution generally occurs shortly after slack tide when historic plume material remaining from
the previous tidal cycle is re-entrained into the effluent plume (Doneker and Jirka, 2012).
Information provided to CORMIX included the period for tidal reversals, maximum current
velocity, and current velocities shortly after slack tide (1 hour). CORMIX tidal predictions
terminate at the point of tidal reversal. Under the most conservative scenario using the
observed current velocities one hour after slack tide, the point of tidal reversal occurs
approximately 98.5 meters from the site. All tida/CORMIX simulations conducted as part of this
investigation terminated at this distance.
CORMIX iterations were conducted to assess:
a) Variations to single-port and multi-port diffuser design options,
b) Variations in environmental conditions (sensitivity analysis), and
c) Variations in effluent flow volumes (initial effluent volume)
d) Variations in effluent salinity (based on potential variations in source-water salinity)
5.1 DISCHARGE DESIGN VARIABLES AND SINGLE-PORT DISCHARGE INVESTIGATION
The distribution and concentrations of parameters from a discharge within the receiving water
body are a function of the hydrodynamic variables of the effluent and the ambient conditions of
the water body. In the proximal region around the discharge, the initial jet characteristics of
momentum flux, buoyancy flux, and outfall geometry determine mixing. In this region, known
as the near-field, the configuration of the diffuser represents the major control on the amount
of mixing that will occur. Dilution of the effluent in the near-field occurs as the discharge
Page 8

RO Effluent Mixing Model Evaluation
Bogue Banks Water Corporation
stream exits the outfall at a higher velocity than the ambient water body, resulting in turbulent
entrainment of the ambient water into the jet plume. As the plume travels farther from the
source, the effluent characteristics exert less influence, and mixing is controlled by ambient flow
conditions and passive diffusion (Doneker and Jirka, 2012).
Details on the simulation inputs and the results of each simulation are included in Tables 7 and
8, respectively. A major control on model results (the amount of mixing) is the configuration of
the outfall. Based on conditions at the site, a cross-flow layout has been chosen for all single-
port and diffuser orientations, meaning that the effluent is discharged away from the shore and
perpendicular to the tide dominated current. This orientation was chosen to avoid a counter-
flow during current reversal; which would reduce mixing. The exact effluent density of the
brine reject from the future RO plant is unknown. Water-quality data obtained from Test Well
10 suggests that source water for the new RO plant may be fresher than source water used for
the existing plant. Initial modeling performed by GMA assumed a source water chloride
concentration of 1230 mg/L, which was the highest value measured in Test Well 10, and a 5x
waste concentration factor. These assumptions resulted in an effluent that was only very
slightly positively buoyant relative to the ambient water (Table 8). Possible variations in source-
water salinity were tested using the final optimized model, and these model results are
discussed in Section 5.5 of this report.
The first variable GMA investigated with respect to the diffuser design options was the vertical
angle of discharge relative to the horizontal. This angle is an important factor in mixing. For
positively buoyant discharges, a horizontal or near-horizontal discharge angle is often favorable
(Doneker and Jirka, 2012). GMA found that discharge angles of both 0° and 5° maximized
initial near-field mixing at the site, but resulted in bottom attachment of the plume. In an
attempt to avoid bottom attachment, GMA also investigated the effects of changing the height
of the discharge port. GMA determined that a singleport discharge with a vertical angle of 5°,
9 9 9 9
elevated 10 inches above the channel bottom, increased mixing of the effluent without causing
bottom attachment.
The discharge velocity is controlled by the port size and the amount of effluent discharged.
mixingthat occurs in the near-field region.
Discharge velocity greatly influences the amount of g
Discharge velocities below 0.5 m/s (1.6 feet per second) can allow sediment or saltwater to
infiltrate the diffuser, although duck-billed diffuser ports that restrict this infiltration could be
used. Excessive discharge velocities may contribute to nozzle erosion if velocities are greater
than 15 feet per second. GMA experimented with discharge velocities that created the greatest
amount of initial mixing while maintaining a desirable discharge velocity. An 8-inch diameter
port was determined to provide good mixing of the plume and an adequate discharge velocity
(1.61 meters per second) at the 1.0 MGD effluent volume. However, the discharge velocity for
this configuration was less than 1 m/s under the anticipated initial effluent volume.
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RO Effluent Mixing Model Evaluation
Bogue Banks Water Corporation
parameters that minimized the spatial extent of the mixingzone and
Optimized designp
maximized near-field mixing were determined iteratively. The CORMIX modeling performed by
GMA has analyzed the external hydraulics affecting mixing of the proposed range of RO effluent
volumes within the ambient fluid based on the port exit velocity. No considerations of internal
pipe hydraulics or required operating pressures were made. Single port discharge simulations
provided a good understanding of the mixing system and the relative effects of changes to
various discharge configurations.
5.2 OPTIMIZED SIMULATION OF A SINGLE-PORT DISCHARGE
CORMIX simulations indicate that at both the initial and future effluent volumes (0.5 and 1.0
MGD, respectively), an elevated, single-port, cross-flowing diffuser is capable of strong initial
mixing in the near-field. The technical parameters of the final optimized single port diffuser
(simulation nameS: 'VERT 5 RISE CONSTRICT' and 'VERT 5 RISE CONSTRICT INITIAL',
Appendix VIII) are as follows:
• Diffuser type: submerged
• Outfall pipe: 105 meters from the shore
• Port diameter: 8 inches
• Height of the discharge port center above the river bottom: 10 inches (0.254 meters)
• Vertical discharge angle: angled at 5° towards the water surface
90°• flow, i.e., a cross-flowingdischarge)
Sigma: (oriented perpendicular to ambient o g )
• Discharge velocity: 1.62 meters per second (1.0 MGD effluent volume), 0.81 meters per
second (0.5 MGD effluent volume)
Simulations indicate that during worst case mixing conditions (i.e. one after hour slack tide) this
design will dilute the concentration of ammonia-nitrogen to less than 2 mg/L above ambient
conditions within 2 meters of the proposed site. In a cross-flowing design, the port is pointed
perpendicular to the ambient current direction and away from the shoreline. The predicted
dilution at the edge of the 10-meter Regulatory Mixing Zone would be 7.6 using a cross-flowing
design and assuming the maximum proposed effluent volume scenario. This dilution factor is
more than is required to meet water-quality standards.
5.3 OPTIMIZED SIMULATION OF A MULTI-PORT DISCHARGE
A multiport diffuser is a linear structure consisting of multiple ports or nozzles that allow an
effluent to be discharged as a series of turbulent jets at high velocity into the ambient receiving
water body. Model results indicate that the water-quality standard for ammonia-nitrogen would
be met within 2 meters of the proposed discharge using the optimized single-port scenario.
However, this design results in a discharge velocity of less than 1 meter per second at the initial
waste volume. Such a low discharge velocity may lead to sediment accumulation within the
pipe. The use of a multiport diffuser would increase discharge velocity and would result in far
better mixing due to the increased surface area for jet entrainment around each discharging jet.
Therefore, a multiport diffuser is preferable.
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RO Effluent Mixing Model Evaluation
Bogue Banks Water Corporation
GMA simulated multi-port diffuser options using the knowledge of the mixing system that was
gained during the single port optimization process. A staged diffuser (i.e. all diffuser nozzles
oriented in the same direction generally following the diffuser line) was modeled in all
scenarios. CORMIX multiport simulations assume a uniform flow distribution across the
modeled diffuser header.
Multi-port simulations indicated that a 3-inch port diameter resulted in the greatest mixing
without inducing discharge velocities that might cause nozzle erosion. The technical
parameters of the final optimized 3-inch, multiport diffuser (simulation: 'MULTI 6') are as
follows:
• Diffuser type: submerged,
• Outfall pipe: 105 meters from the shore
• Diffuser length: 20 feet
• Number of ports: 3 single ports; spacing: 6.7 feet; average diameter: 3 inches
• Height of the discharge port center above the river bottom: 10 inches (0.254 meters)
• Vertical discharge angle: 5°
• Gamma: 90°, Sigma: 90°, Beta: 0° (perpendicular, staged diffuser resulting in a cross-
flowing discharge)
• Discharge velocity: 3.84 meters per second
The location and orientation of the optimized diffuser are shown in Figure 5. Low discharge
velocities may lead to undesirable sediment accumulation within the discharge pipe. The
utilization of the optimized multi-port diffuser greatly enhanced initial near-field mixing while
maintaining desirable discharge velocities under both initial and future predicted waste volumes
(1.92 m/s and 3.84 m/s, respectively) (Table 8, Simulation name: MULTI 6; Appendix VIII).
This discharge configuration resulted in rapid dilution of the effluent plume with concentrations
falling below the water-quality standard within 1 meter of the outfall. Under the 1-hour post
slack tide ambient water velocity, the plume is predicted to have traveled approximately 100
meters in the direction of flow before tidal reversal occurs. At the point of tidal reversal under
this scenario, the model predicts an ammonia-nitrogen concentration of only 0.11 mg/L.
Figure 6 illustrates a plan view of the simulated plume for the final multi-port diffuser simulation
described above. Once the momentum of the effluent jets slows and near-field processes no
longer dominate, the plume begins to spread laterally and is advected by the ambient current.
Note that the ammonia-nitrogen water-quality standard is met within 1 meter of the discharge.
Figure 7 illustrates the concentration excess (i.e. the concentration of ammonia-nitrogen above
background, which is assumed to be zero) versus the distance the center of the plume travels
from the multi-port diffuser. As shown in the graph, the concentration of chloride rapidly
declines to below the water-quality standard within a meter of the discharge. Similarly, Figure
Page 11

RO Effluent Mixing Model Evaluation
Bogue Banks Water Corporation
8 shows the dilution versus the distance the plume has traveled downstream. The dilution
illustrated on this graph would be applicable to other potential effluent constituents.
5.4 CORMIX SENSITIVITY ANALYSIS
GMA performed a sensitivity analysis to evaluate the effects of potentially changing ambient
conditions. Table 6 gives details of the observed and inferred ambient variables at the
proposed effluent outran. Design recommendations provided by CORMIX suggest variations to
ambient conditions on the order of 25% to test model sensitivity. In order to better
characterize the uncertainty in ambient environmental data, and to account for extreme
conditions that might occur at the site, GMA altered ambient variables as follows:
• Maximum Current Speed — 50%, 75%, 125%, and 200% of observed
• Wind Speed — minimum and maximum observed wind based on 5 years of weather
records
• Current Speed 1 Hour After Slack Tide — 50%, 75%, 125%, and 200% of observed.
• Water density— minimum and maximum ambient water densities based on historic
water-quality monitoring data from NCDEQ station P9580000
• Discharge Water Depth — range of measured ambient water depth 3.2 — 5.3 feet
The sensitivity analysis was performed using the optimized multiport diffuser design discussed
in Section 5.3, discharging at 1.0 MGD. The results of the simulations performed as part of the
sensitivity analysis are included in Table 8.
Maximum ambient current and ambient water-body density had very little effects on mixing
characteristics of the modeled system. CORMIX simulations for the conditions at the study site
were sensitive to:
• Changes in wind speeds
o As expected, changes to wind speed did not affect near-field dilution. Increased
wind speed resulted in increased dilution in the far field (beyond 6.55 meters
under a 1.0 MGD discharge volume), and decreased wind speeds reduced far
field dilution.
o Regardless, predicted ammonia-nitrogen concentrations were far below water
quality goals within the near-field, and therefore wind is not expected to hinder
mixing at the site.
• Changes in current speed at one hour after slack tide
o Changes in current speed at one hour after slack tide had the greatest effect on
mixing.
o Decreased current speed at one hour after slack tide resulted in increased
ammonia-nitrogen concentrations at the end of the near field, and increased
current speeds at one hour after slack tide decreased the predicted ammonia-
nitrogen concentration. Regardless, the water-quality standard was met within 1
Page 12

RO Effluent Mixing Model Evaluation
Bogue Banks Water Corporation
meter of the outfall in all simulations.
• Changes in ambient water depth at the outfall
o A simulation modeling an extreme low ambient water depth of only 3.2 feet at
the discharge site resulted in reduced mixing, but the predicted ammonia-
nitrogen concentration at the end of the near field, 0.22 mg/L, remained well
below the water quality standard.
5.5 SIMULATIONS OF VARIED SOURCE WATER SALINITY
The majority of the simulations run by GMA were based on the anticipated future expansion of
the proposed RO plant to 4 MGD of finished water (1.0 MGD of reject discharging 20 hours per
day). GMA ran an additional simulation at the initial average daily reject volume of 0.5 MGD
discharging for 20 hours per day. Under the initial reject production volumes, using the
optimized multi-port diffuser design, dilution of the effluent remained high, and ammonia-
nitrogen continued to be rapidly diluted to below the water-quality standard within a meter of
the outfall (Table 8, Effluent Volume Change simulation). The model predicts that
concentrations of ammonia-nitrogen will be lower under the initial effluent volume scenario,
despite the reduced effluent velocity, than under the full build out. Therefore, GMA believes
that the optimized diffuser described in this study will perform well during both the initial and
the future phases of the plant.
6.0 CONCLUSIONS AND RECOMMENDATIONS
An extensive site investigation was performed by GMA that provided details on the nature of the
ambient conditions at the proposed future BBWC RO discharge site near the Emerald Isle Boat
Ramp. GMA utilized CORMIX to simulate the majority of the ambient, discharge volume, and
effluent concentration conditions that are likely to occur at the site. Based upon the predicted
RO reject chemistry and current surface water standards, GMA has modeled the dilution of
ammonia-nitrogen in CORMIX simulations as the primary mixing constituent. GMA modeled
mixing of the brine effluent under a worst-case scenario following slack-tide conditions and
using a maximum ammonia-nitrogen concentration of 5 mg/L.
The CORMIX model predicts that using a 3-port multiport diffuser, 20 feet in length, oriented
perpendicular to ambient flow direction, and with ports elevated 10 inches above the channel
bottom, effluent concentrations of ammonia-nitrogen were diluted to well below the 2B water
quality standard of 2 mg/L within only 1 meter of the outfall under both current and future
predicted effluent volumes. Dilution remained strong using this scenario in all ambient
conditions predicted to occur at the site.
CORMIX predicts that ammonia-nitrogen concentrations would be rapidly diluted to below the
water quality standard within only a meter of the optimized diffuser. However, like all models,
mixing zone simulations have some degree of inherit error. CORMIX simulations are generally
accurate to within + 50% of the standard deviation of the data. Therefore, GMA recommends
Page 13

RO Effluent Mixing Model Evaluation
Bogue Banks Water Corporation
that a regulatory mixing zone of 10 meters around the diffuser pipe be established for this
location. The model indicates that the required dilution should easily occur within this distance,
which represents only about 4% of the channel width between the shore and Long Marsh.
Diffuser details and suggested orientations discussed in this report are for mixing modeling
purposes only. Actual design of the facilities to be used for effluent discharge on this project
are outside of the scope of this study and will be performed at a later date by a NC licensed
Professional Engineer. Mixing modeling was based on effluent velocity and receiving water
body characteristics. If the actual diffuser design is different than what has been modeled in
this report, additional CORMIX simulations may be necessary to evaluate the mixing
characteristics of the discharge.
GMA believes that the current CORMIX simulations are good planning tools to estimate the
potential effects of the proposed discharge. Simulations indicate that by using a multi-port
diffuser, effluent concentrations of ammonia-nitrogen should be easily diluted to less than 2
mg/L above ambient background concentrations within 10 meters of the proposed site. Thus,
modeling results support the use of the discharge location near the Emerald Isle Boat Ramp as
an environmentally sound disposal option for the future BBWC RO reject water.
7.0 REPORT CERTIFICATION
This report was prepared by GMA, a professional corporation licensed to practice geology (#C-
121) and engineering (#C-0854) in the state of North Carolina.
: v 91��6
:u = 11
Emma H. Shipley, P 'Z�'' G, Q= ames K. Holley, PG
Project Hydrogeologist %I ".• .0 0C- c.4s Senior Hydrogeologist
%� N,,,o+°+
� RDISO.*......,N......,
8.0 REFERENCES
Doneker and Jirka, 2012, "CORMIX User Manual: A Hydrodynamic Mixing Zone Model and
Decision Support System for Pollutant Discharges Into Surface Waters", US
Environmental Protection Agency, Washington, D.C., 236 pages.
Hymel, S.N. 2009. Inventory of Marine and Estuarine Benthic Macroinvertebrates for Nine
Southeast Coast Network Parks. Natural resource Report NPS/SECN/NRR — 2009/121.
149 pages.
Page 14

RO Effluent Mixing Model Evaluation
Bogue Banks Water Corporation
NCDENR. 2007. "Redbook" Surface Waters and Wetlands Standards. NC Administrative Code
15A NCAC 02B .0100, .0200 & .0300. Amended effective May 1, 2007.
NCDWR. 2017. "Classifications" NCDEQ Division of Water Resources. Available at:
https://deci.nc.gov/about/divisions/water-resources/planning/classification-
standards/classifications
NCDWQ. 1999. "Mixing Zones in North Carolina". North Carolina Department of the
Environment and Natural Resources, Division of Water Quality. 5 pages.
Page 15

FIGURES

Jones
County
Carteret
58 County
�. n'
WaY
Fredo
e
X c0 241
gogueSound
Onslow (0
County a
24 58 Emerald Dr.
71(
1 INCH = 1,650 FEET ;
LONG MARSH
Plan
Oc
can
P EMERALD ISLE •
BOAT RAMP\ I `
r,
r
tt
LEGEND
0 1.5 3 GMA
COUNTY BOUNDARIES KNJM WEATHER STATION
11
ROADS WATER QUALITY STATION P9580000 MILES -�
♦ WELL 11 PROPOSED BBV11C WTP OUTFALL
FILE: DRAWINGS/24312/ STUDY AREA DATE: 6/19/2018
Figure_1_Study_Area
FUTURE BBWC RO WASTEWATER MIXING STUDY,
PROJECT NO. 24312 FIGURE 1
CARTERET COUNTY, NORTH CAROLINA

Figure 2: Example of CORMIX flow classification chart. CORMIX Model, BBWC Proposed RO Discharge, Carteret County,
NC (GMA Project #: 24312).
FLOW CLASSIFICATION
SUBMERGED POSITIVELY BUOYANT GMA MULTIPORT DIFFUSER DISCHARGE
IN UNIFORM LAYER(HEIGHT Hs)
Deep Layer Shallow Layer
Stable Discharge /M(1 + Cost it )2 1 M-C4a ho srn Y Unstable Discharge
+ —
<1 Hs fm
t
Diffuser
Type
Weak • Strong •
Current / £M\Current Unidirectional Staged Alternating
<t``£m/>> Diffuser Diffuser Diffuser
C4 i
• • •
Alnment Alignmen Alignment
Angle Angle ` Angle
Perpendicular >45
Perpendicular >ig45' Perpendicular'>s5'
<45' Parallel a5' Parallel <45' Parallel
Pm em
i Hs Hs
Weak >1 s<t Strong Weak <t Strong
I • Current Current Current Current •
`M�U/1V U2 _Mr3�/ i MU4 y U5 MIU6 MU? MU9
S u S —► P —► P -' q P -` P —e. P -- P
S=Side View P=Plan View

NORTH CHANNEL PROFILES SOUTH LEGEND
PAS
�� _ FLOWRCEL METERBOUNDARIE LOCATION
5 1-
a.
1 , i 1 10 o LONG MARSH STAFF GAUGE
900 800 700 600 500 400 300 200 100 0 CROSS-SECTION 1
FEET NORTH OF SOUTHERN SHORE
VERTICAL EXAGGERATION=10X CROSS-SECTION 2
t, CROSS-SECTION 3
,
,
a SAMPLE LOCATIONS
- 1 GRAIN SIZE & BENTHIC
', MACROINVERTEBRATE
t
o` t BENTHIC
A MACROINVERTEBRATE
• A' ONLY
, •
• • •
• A
•
• •
• • PROJECT: 24312
4\ tb4"/
• •
STAFF GAUGE AND CHANNEL
}}�' CROSS-SECTION LOCATIONS
.\ t 11‘,‘ \\‘ , 't
FIGURE 3 DATE 05/23/2018
t 1 \
0 250 500'
1 ,.=250'
c\ \
I BOGUE BANKS WATER CORPORATION
x CARTERET COUNTY, NORTH CAROLINA
i EMERALD ISLE `1= I
"`. BOAT RAMP
GMAi 1
, , %, _ ........
N1 41' ... , \ \ \ ..''''''...r'.7'
4. GROUNDWATER MANAGEMENT ASSOCIATES,INC. I
ter... sa- " s.:_ - IL

A. NORTH
START DATA COLLECTION
25000 OCT. 20, 2017
W + D
-25000 25000 50000 75000 100000 -I
(FEET)
-25000
H
-50000 w
U-
END DATA COLLECTION
OCT. 27, 2017
-75000
-100000
SOUTH
NORTH
B.
30
20
10
WEST 27G 30 20 1c 20 30 9G EAST
10
20
3G
SOUTH
Figure 4. Progressive Vector Plot (A) and Rose Diagram (B) of Currents at the Proposed Discharge
Location. CORMIX Model, BBWC, Carteret County, NC (GMA Project #: 243124).

a .. LEGEND
Ailiiiiill LONG MARSH
PARCEL BOUNDARIES
DIFFUSER
Cross-sectional view of diffuser looking east-northeast.
Drawing not to scale.
PROPOSED 10 METER
REGULATORY MIXING
ZONE
T PROJECT: 24312
le\\‘' ,i
1.\ .
1T-?.t
3� OPTIMIZED DIFFUSER
ORIENTATION
} 0.r FIGURE 5 DATE 6/11/2018
0 150 300'
1\
1 ' = 150'
^ BOGUE BANKS WATER CORPORATION
•! , CARTERET COUNTY, NORTH CAROLINA
...„
f GMAS
N
. , .
, ,
. \
" GROUNDWATER MANAGEMENT ASSOCIATES,INC.

Figure 6: Plan View of Plume Geometry using an Optimized Multi-Port Diffuser. CORMIX Model, BBWC Proposed RO Discharge,
Carteret County, NC (GMA Project #: 24312).
�+ End of Near Field
3 Region (NFR) Ambient Current At 1
30 c (-6.5 m from Hour after Slack Tide
3 N diffuser) = 3.84 m/s
20
_I V
Diffuser
Pipe
\10
I 0 - meters
-10 1(icf
-10
E
0
-20-- cc
G!
O.
2 Discharge Excess (mg/1)
G MA S 0.10 0.39 1.53 6.00
Visualization is an approximation.

Figure 7: Concentration Excess versus Distance using an Optimized Multi-Port Diffuser. CORMIX Model, BBWC Proposed RO
Discharge, Carteret County, NC (GMA Project #: 24312).
Concentration vs. Centerline Trajectory Distance
6
E
5- o,�
J �
Oa a/
0
4 a
c 2
0
a
00
U
a) 3-
>
0
Water Quality Standard for
ammonia-nitrogen(2 µg/L)
• 2
a,
U
c
0
1
p
0
Downstream Distance(m) 80 1100 GMA

Figure 8: Dilution versus Distance using an Optimized Multi Port Diffuser. CORMIX Model, BBWC Proposed RO Discharge, Carteret
County, NC (GMA Project #: 24312).
Dilution vs. Downstream Distance
50
45 - 0
N
40 -
v
0
35 - 0.
30 -
c
0 i
25 -
o
20 -
15 -
10 -
5-
0
0 20 40 60 80 100
Downstream Distance(m) GMA

TABLES

Table 1. Summary of Monitoring and Sample Site Locations
Bogue Banks Water Corporation, Carteret County, NC (GMA Project #: 24312)
Sample
ID Description Latitude Longitude Core
+
Depth
(inches)
SG Staff Gauge 34.66752 -77.00660 -
FM Flow Meter 34.67476 -77.00596 -
MB1 Benthic Macroinvertebrate Sample 34.67468 -77.00631 3
MB2 Benthic Macroinvertebrate Sample 34.67479 -77.00617 3
MB3 Benthic Macroinvertebrate Sample 34.67458 -77.00596 3
MB4 Benthic Macroinvertebrate Sample 34.67467 -77.00569 3
MB5 Benthic Macroinvertebrate Sample 34.67491 -77.00577 3
MB6 Benthic Macroinvertebrate Sample 34.67493 -77.00595 2
GS1 Grain Size Sample 34.67458 -77.00596 3
GS2 Grain Size Sample 34.67467 -77.00569 3
GS3 Grain Size Sample 34.67491 -77.00577 3
GS4 Grain Size Sample 34.67493 -77.00595 3
GS5 Grain Size Sample 34.67468 -77.00631 3
+Sample depth measured below the bottom of the river.

Table 2. Field Water-Quality Observations and Analytical Results
Bogue Banks Water Corporation, Carteret County, NC (GMA Project #: 24312)
Flow Meter Station
Latitude: 34.67476, Longitude: -77.00576
Near High Tide Near Low Tide
10/20/2017 10:20 10/20/2017 13:25
Depth (ft) 0.5 3.0 6.0 0.5 3.0 ' 5.0
Temp(°C) 19.8 19.7 19.7 21.4 20.9 20.7
DO(mg/L) 7.51 7.28 8.24 8.19 8.25 8.48
ORP(mv) 138.3 160.7 142.1 141.9 143.2 149.7
Conductivity(pS/cm) 35,875 48,227 28,426 40,192 39,439 37,061
Specific Conductance(pS/cm) 39,839 53,506 31,685 43,145 42,787 40,379
pH 7.97 7.28 7.97 8.03 8.01 7.79
Turbidity(NTU) - 8.21 - - 7.72 -
Estimated Salinity(ppt) - 23.31 - - 25.65 -
Ammonia Nitrogen (mg/L) - 0.3 - - <0.2 -
Total Kjeldahl Nitrogen (mg/L) - 0.7 - - 0.7 -
Total Dissolved Solids(TDS) - 38,000 - - 37,000 -
Chloride(mg/L) - 12,900 - - 14,200 -
Total Phosphorus(mg/L) - 0.08 - - 0.1 -
Total Nitrogen (mg/L) - 0.7 - - 0.7 -
Total Nitrogen (Calc)
-Nitrate+Nitrite-Nitrogen <0.02 - <0.02 -
-

Table 3. Summary of Grain Size Analyses
Bogue Banks Water Corporation, Carteret County, NC (GMA Project #: 24312)
Percent of Sample
Grain Size
(mm) USCS Size Terms GS1 GS2 GS3 GS4 GS5
19.0-76.2 coarse 0.0 0.0 0.0 0.0 0.0
4.76-19.0 Gravel fine 0.0 0.0 0.0 0.0 0.0
2.00-4.76 coarse 0 0 0 0 0
0.420-2.00 Sand medium 1.2 0.1 0.2 0.2 0.2
0.074-0.420 fine 84.2 91.2 89.1 92.1 92.8
0.005-0.074 Silt 3.7 4.2 4.3 3.6 3.0
<0.005 Clay 10.9 4.5 6.4 4.1 4.0
Total 100 100 100 100 100

Table 4. Discharge Variables for the Proposed RO Outfall
Bogue Banks Water Corporation, Carteret County, NC (GMA Project #: 24312)
Range
Discharge Variable Minimum Maximum Plan / Comments
Primarily effects discharge velocity. Maximum diameter
based on anticipated diameter of proposed force main. Port
Port Diameter (inches) 2 10 diameters resulting in discharge velocities of less than 0.5
m/s may lead to undesirable sediment accumulation within
the pipe.
A deep discharge that increases the path length of the
Center of Port Height 5 17 positively buoyant plume is recommended. Disharge ports
(inches) were elevated slightly off of the bottom to reduce the chance
for bottom attachment of the plume.
Velocities below 0.5 m/s can allow sediment to infiltrate port,
pipe, or diffuser. Generally recommended velocity for single
port nozzles or diffusers is 3 to 8 m/s. The engineer that
Discharge Velocity (m/s) 0.81 6.48 worked on the existing RO diffuser design previously
recommended a discharge velocity of 4.5 m/s or less to
reduce discharge nozzle erosion. RO plant assumed to
operate 20 hours per day.
Outfall Location All simulations modeled the proposed outfall location,
105 approximately 105 feet north of the shore near the Emerald
(meters) Isle Boat Ramp.
For positively buoyant discharges, a flat to slightly upward
Vertical Angle (degrees) 0 60 discharge angle allows for the greatest initial mixing in
shallow water bodies. Vertical angles of 0, 5, 15, and 60
were tested.
Angle of discharge Due to the tidal nature of flow at the site, a crossflowing (90
relative to flow 270 or 270 degrees relative to ambient flow direction) design is
(degrees) recommended to enhance mixing.

Table 5. Effluent Variables for the Proposed RO Outfall
Bogue Banks Water Corportation, Carteret County, NC (GMA Project #: 24312)
Effluent Variable I.Modeled Value(s) Plan/Comments
The maximum ammonia-nitrogen (NH3-N) concentration
NH3-N 5 mg/L measured during 2017 effluent monitoring from the existing
RO reject stream was 4.48 mg/L. GMA modeled an effluent
concentration of 5 mg/L NH3-N as a worst case scenario.
Effects discharge velocity. Low end of range based on
anticipated daily waste volume produced under initial 2 MGD
Discharge Volume (MGD) 0.5 - 1.0 finished water volume with 20% reject. High end of range
based on future expansion to 4 MGD of finished water.
Assumed RO plant operates 20 hours per day.
3 Density calculated based on Test Well 10 chloride analyses and
Density of Effluent (kg/m ) 998.59 1024.580 current RO plant effluent concentrations.
ug/L - micrograms per liter
MGD - million gallons per day
kg/m3 - kilograms per cubic meter

Table 6. Ambient Variables at the Proposed RO Outfall Location
Bogue Banks Water Corportation, Carteret County, NC (GMA Project #: 24312)
Ambient Base Modeled Sensitivity
Variable Value Range Plan/Comments
Maximum Observed maximum current speed. Variations of
Current Speed 0.324 0.162 - 0.648 50%, 75%, 125%, and 200% of the average were
(m/s) used for sensitivity analysis.
Water Depth at Approximate water depth at the proposed site.
Discharge 4.3 3.2-5.3 Variations include approximate depths at low and
Location (ft) high tide.
Average wind speed during the field study.
Wind Speed Variations encompassing the observed min and max
(mph) 5.88 0 - 15 daily avg wind gusts over a 5 year period from a
NOAA weather buoy at Station BFTN7 near Beaufort
were used for sensitivity analysis.
Tide Reversal 12.31 n/a Using 12.31 hours based on flow study data.
(hours)
Speed 1� Observed current Current
speed one hour after tidal reversal.
p
Hour After Tide 0.172 0.0859 - 0.344 Variations of 50%, 75%, 125%, and 200% of the
m s average were used for sensitivityanalysis.
Reversal ( / ) 9 Y
Sensitivity analyses were based on historic salinity
Salinity (ppt) 24.48 7 37 data obtained from NCDWQ Water Quality Station
P958000 in the Bogue Sound at channel marker G15
near Salter Path.
Water Average value from the field study used for the base
Temperature 20.37 1 30 simulation. Sensitivity analyses were based on
(°C) historic temperature data obtained from NCDWQ
Water Quality Station P958000
Base simulation based on average temperature and
salinity during field study. Sensivity analyses were
Density of 1016.67 1000.87 - based historical temperature and salinity data
Water (kg/m3) 1029.65 obtained from NCDWQ Water Quality Station
P958000. Highest values associated with cold water
and highest salinities.
n/a = not applicable
ft/s = feet per second
mph = miles per hour
PSU = practical salinity unit
°C = degrees Celcius
kg/m3 - kilograms per cubic meter

Table 7. CORMIX Simulation Variables, Bogue Banks Water Corportation, Carteret County, NC(GMA Project#: 24312)
Ambient Variables Effluent Variables Discharge Variables
Current Port Port Angle of
Water Speed Maximum Density of Discharge Center Center
Wind Tide Effluent Outfall Vertical discharge
Type Simulation Name Depth at 1-Hour Current Ambient Flow concentration Port Size Port Size Height Height
Speed Reversal Density Pollutant Type Location Angle relative to
Discharge After Slack Speed Water (gpm) of NH3-N 3 (inches) (meters) above above
(m) (m/s) (hours) Tide (m/s) (kg/m3) (mg/L) (kg/m) Bottom Bottom (m) (degrees) flow
(m/s) (in) (m) (degrees)
BASE(VERT 0) 1.31 2.63 12.31 0.172 0.324 1016.67 833 5 1006.61 Conservative 10 0.254 5 0.127 105 0 90
VERT 60 1.31 2.63 12.31 0.172 0.324 1016.67 833 5 1006.61 Conservative 10 0.254 5 0.127 105 60 90
VERT 15 1.31 2.63 12.31 0.172 0.324 1016.67 833 5 1006.61 Conservative 10 0.254 5 0.127 105 15 90
VERT 5 1.31 2.63 12.31 0.172 0.324 1016.67 833 5 1006.61 Conservative 10 0.254 5 0.127 105 5 90
IA
z VERT 0 RISE 1.31 2.63 12.31 0.172 0.324 1016.67 833 5 1006.61 Conservative 10 0.254 11 0.2794 105 0 90
0
0
mVERT 0 RISE 1 1.31 2.63 12.31 0.172 0.324 1016.67 833 5 1006.61 Conservative 10 0.254 17 0.4318 105 0 90
F
►,
a
it VERT 5 RISE 1.31 2.63 12.31 0.172 0.324 1016.67 833 5 1006.61 Conservative 10 0.254 11 0.2794 105 5 90
0
a
W
VERT 5 RISE 2 1.31 2.63 12.31 0.172 0.324 1016.67 833 5 1006.61 Conservative 10 0.254 8 0.2032 105 5 90
z
a VERT 5 RISE 2
CONSTRICT 1.31 2.63 12.31 0.172 0.324 1016.67 833 5 1006.61 Conservative 8 0.203 7 0.1778 105 5 90
VERT 5 RISE 1.31 2.63 12.31 0.172 0.324 1016.67 833 5 1006.61 Conservative 8 0.203 10 0.254 105 5 90
CONSTRICT
VERT 0 RISE 1.31 2.63 12.31 0.172 0.324 1016.67 833 5 1006.61 Conservative 8 0.203 10 0.254 105 0 90
CONSTRICT
VERT 5 RISE
CONSTRICT 1.31 2.63 12.31 0.172 0.324 1016.67 417 5 1006.61 Conservative 8 0.203 10 0.254 105 5 90
INITIAL
I- z
0
gMULTI 1-MULTI 7 1.31 2.63 12.31 0.172 0.324 1016.67 833 5 1006.61 Conservative SEE TABLE 9
J m
a _
a Ambient Max Current
y (50%) 1.31 2.63 12.31 0.162 0.162 1016.67 833 5 1006.61 Conservative
Y
J
a Ambient Max Current 1.31 2.63 12.31 0.172 0.243 1016.67 833 5 1006.61 Conservative
et (75%)
SEE TABLE 9-MULTIPORT 6 CONFIGURATION
Ambient Max Current 1.31 2.63 12.31 0.172 0.405 1016.67 833 5 1006.61 Conservative
E (125%)
a
z Ambient Max Current 1.31 2.63 12.31 0.172 0.648 1016.67 833 5 1006.61 Conservative
a (200%)
page 1 of 2

Table 7. CORMIX Simulation Variables, Bogue Banks Water Corportation, Carteret County, NC(GMA Project#: 24312)
Ambient Variables Effluent Variables Discharge Variables
Current Port Port Angle of
Water Wind Tide Speed Maximum Density of Discharge Effluent Center Center Outfall Vertical discharge
Type Simulation Name Depth at 1-Hour Current Ambient Flow concentration Port Size Port Size Height Height
Speed Reversal Density Pollutant Type Location Angle relative to
Discharge After Slack Speed Water (gpm) of NH3-N (inches) (meters) above above
(m) (m/s) (hours) Tide (m/s) (kg/m3) (mg/L) (kg/m3) Bottom Bottom (m) (degrees) flow
(m/s) (in) (m) (degrees)
Ambient Water Depth 0.98 2.63 12.31 0.172 0.324 1016.67 833 5 1006.61 Conservative
Min
Ambient Water Depth 1.62 2.63 12.31 0.172 0.324 1016.67 833 5 1006.61 Conservative
Max
Ambient Wind Min 1.31 0.0 12.31 0.172 0.324 1016.67 833 5 1006.61 Conservative
u) Ambient Wind Max 1.31 15.0 12.31 0.172 0.324 1016.67 833 5 1006.61 Conservative
Fi
.
r
Ambient Current
Z4 Speed 1 Hr(50%) 1.31 2.63 12.31 0.086 0.324 1016.67 833 5 1006.61 Conservative
4
Ambient Current 1.31 2.63 12.31 0.129 0.324 1016.67 833 5 1006.61 Conservative
C Speed 1 Hr(75%)
m Ambient Current
Speed 1 Hr(125%) 1.31 2.63 12.31 0.215 0.324 1016.67 833 5 1006.61 Conservative
Ambient Current 1.31 2.63 12.31 0.344 0.344 1016.67 833 5 1006.61 Conservative SEE TABLE 9-MULTIPORT 6 CONFIGURATION
Speed 1 Hr(200%)
Ambient Density Low 1.31 2.63 12.31 0.172 0.324 1000.87 833 5 1006.61 Conservative
Ambient Density High 1.31 2.63 12.31 0.172 0.324 1029.65 833 5 1006.61 Conservative
Initial Effluent Vol 1.31 2.63 12.31 0.172 0.324 1016.67 417 5 1006.61 Conservative
E -p r (0.5 MGD over 20 hrs)
w > U
• ate+ MULTI 6 SALTIER 1.31 2.63 12.31 0.172 0.324 1016.67 833 5 1016.67 Conservative
VI f0 53 •C
m u ip
► MMC A6 1.31 2.63 12.31 0.172 0.324 1016.67 833 5 998.59 Conservative
Bold indicates a variable being altered for sensitivity analysis. Green indicates an optimized variable based on previous simulations.
`Sensitivity analyses were performed on the MULTI 6(optimized)discharge configuration.
page 2 of 2

Table 8.CORMIX Simulation Results,Bogue Banks Water Corportation,Carteret County,NC(GMA Project#:24312)
Near Field Near Field 10-m RMZ 10-m
Discharge Buoyant Time to End of Ambient WQ WQ Standards NH3 N Conc.
Termination Conc.of NH3 Near Field Conc. RMZ Flow Flow Class
Type Simulation Name Velocity Accleration Near Field Standard Met At at Tidal Reversal Flow Description
Coordinates N Dilution of NH,-N Dilution 9 Class Diagram
(m/s) (m/s') (m) (secs) (mg/L) (mg/L) (mg/L) Coordinates(m) (m /L)
- x=4.79 x=0.70 Buoyant submerged discharge in
BASE(VERT 0) 1.04 0.097 y=4.24 19 0.45 11.2 0.38 13.3 2 y=2.17 0.18 H4-90A3 uniform density layer;bottom -
Z=1.31 z=0 attached •.... ':-:.::.
x=10.68 x=4.02
VERT 60 1.04 0.097 y=3.10 61 1.82 2.7 1.84 2.7 2 y=1.90 0.32 S Near vertical,buoyant submerged I
z=131 z=1.31 discharge in uniform density layer 1 '
x=1.31 x=0.43
VERT 15 1.04 0.097 y=2.44 5 1.32 3.8 0.92 5.4 2 y=1.66 0.27 H4-90 Buoyant submerged discharge in -
>-t 31 z=0 73 uniform density layer
x=4.79 x=0.70 Buoyant submerged discharge in -v.--
VERT VERT 5 1,04 0.097 y=4.24 19 0.45 11.2 0.38 13.3 2 y=2.17 0.18 H4-90A3 uniform density layer;bottom -
l
7=1 31 7=0 attarhed
m x=4.79 x=0.70 Buoyant submerged discharge in - , •
0 VERT 0 RISE 1.04 0.097 y=4.24 19 0.45 11.2 0.38 13.3 2 y=2.17 0.18 H4-90A3 uniform density layer;bottom -
z=1.31 z=0 attached _
x=1.78 x=0.46 n ,:
• VERT 0 RISE 1 1.04 0.097 y=2.78 6 1.12Buoyant submerged discharge in 4.5 0.81 6.2 2 y=1.77 0.26 H4-90 ��
N z=1.31 z=0.60 ,....1
uniform density layer
x=1.70 x=0.45 w
p VERT 5 RISE 1.04 0.097 y=2.72 6 1.13 4.4 0.81 6.1 2 y=1.75 0.26 H4-90 Buoyant Submerged discharge in //,
a z=1.31 z=0.60 uniform density layer , ,r,
ti x=1.85 x=0.45 $49,g
O Buoyant submerged discharge in
.z, VERT 5 RISE 2 1.04 0.097 y=2.78 6 1.05 4.8 0.76 6.6 2 y=1.75 0.26 H4-90H z=1.31 z=0.52 uniform density layer Pr
VERT 5 RISE 2 x=5.72 x=0.48 Buoyant submerged discharge in 'r,..
1.62 0.097 y=5.48 22 0,32 15.4 0.29 17.4 2 y=2.22 0.15 H4-90A3 uniform density layer;bottom
z=0 attached ��„_
CONSTRICT z=1.31
x=1.78 x=0.32
VERT 5 RISE Buoyant submerged discharge in i-/ I
CONSTRICT 1.62 0.097 y=3.46 6 0.92 5.5 0.66 7.6 2 y=1.95 0.23 H4-90 uniform density layer ,�
z=1 31 z=0.51 _
VERT 0 RISE x=5.72 x=0.48 Buoyant submerged discharge in _ • '4'•
CONSTRICT 1.62 0.097 y=5.48 22 0.32 15.4 0.76 17.4 2 y=2.22 0.15 H4-90A3 uniform density layer;bottom
z=131 z=0 attached ---- "" '-
.-_
VERT 5 RISE x=2.18 x=0.37
CONSTRICT 0.81 0.097 y=1.86 8 0.76 6.6 0.57 8.8 2 y=1.08 0.13 H4-90 Buoyant submerge ischarge in .71
INITIAL z=1.31 - r-0.46 uniform densitylayer ft
x=6.55 x=0.05 Submerged positively buoyant ,_MS '
MULTI 1 1.62 0.097 y=-1.10 38 0.13 39.2 0.13 39.8 2 y=-0.01 0.09 MU6 multiport diffuser discharge in
z=1.31 z=0.26 uniform laver -1 °
m x=6.55 x=0.05 Submerged positively buoyant _5S8
0 MULTI 2 2.88 0.097 y=-1.96 38 0.12 40.8 0.12 41.4 2 y=-0.01 0.09 MU6 multiport diffuser discharge in _ 11
r z=1.31 z=0 26 uniform laver !°1-
j x=6.55 x=0.05 Submerged positively buoyant 1 N6_ i
Y MULTI 3 6.48 0.097 y=-4.40 38 0.11 44.6 0.11 45.0 2 y=-0.03 0.08 MU6 multiport diffuser discharge in • -3,,�°:
n
r x=6.55 x=0.05 Submerged positively buoyant --.W.-6,-
2. MULTI 4 2.88 0.097 1.96 38 0.18 28.2 0.17 29.3 2 0.02 0.11 MU6 multipart diffuser discharge in
O Y=- Y=- P r9
4 z=1.31 z=0 26 uniform laver
.1x=6.55 x=0.06 Submerged positively buoyant - 177, "
o MULTI 5 2.88 0.097 y=-1.96 38 0.32 15.6 0.29 17.1 2 y=-0.02 0.16 MU6 multiport diffuser discharge in �€
F z=1 31 z=0.26 uniform laver M�°
x=6.55 x=0.05 Submerged positively buoyant l
MULTI 6 3.84 0.097 y=-2.61 38 0.17 29.3 0.16 30.3 2 y=-0.02 0.11 MU6 multiport diffuser discharge in C 1
z=131 z=0.26 uniform laver °
Ambient Max Current x=6.55 x=0.05 Submerged positively buoyant r
w 50% 3.84 0.097 y=-2.97 41 0,19 26.7 0.18 27.3 2 y=-0.02 0.13 MU6 multiport diffuser discharge in ' _
'in- ( ) z=1.31 z=0.26 uniform layer ,11---P
a Ambient Max Current x=6.55 x=0.05 Submerged positively buoyant • J ti(T
z 3,84 0.097 y=-2.61 38 0.17 28.8 0.17 29.7 2 y=-0.02 0.11 MU6 multiport diffuser discharge in
4 (75 o) z=1.31 z=0.26 uniform layer - '�P
x=6.55 x=0.05 Submerged positively buoyant .1.tS 11
Ambient Max Current 3 84 0.097 y=-2.61 38 0.17 29.6 0.16 30.8 2 y=-0.02 0.11 MU6 multiport diffuser discharge in _;}!/
(125%)vi z=1.31 z=0.26 uniform layer ^' P'.
N Ambient Max Current x=6.55 x=0.05 Submerged positively buoyant -2. 11
(2 Man 3.84 0.097 y=-2.61 38 0.17 30.1 0.16 31.4 2 y=-0.02 0.10 MU6 multiport diffuser discharge in 1F °!I
z=1.31 z=0.26 uniform layer __
page 1 of 2

Table 8.CORMIX Simulation Results,Bogue Banks Water Corportation,Carteret County,NC(GMA Project#:24312)
Near Field Near Field 10-m RMZ 10-m
Discharge Buoyant Time to End of Ambient WQ WQ Standards NHS N Conc.
Termination Conc.of NH3 Near Field Conc. RMZ Flow Flow Class
Type Simulation Name Velocity Accleration Near Field Standard Met At at Tidal Reversal Flow Description
(m/s) (m/s') Coordinates (secs) N Dilution of NH3-N Dilution (mg/L) Coordinates(m) (mg/L) Class Diagram
(m) (mg/L) (mg/L)
Ambient Water Depth x=4.9 x=0.04 Submerged positively buoyant !2,:
Min 3.84 0.097 y=-3.48 28 0.22 23.1 0.21 24.2 2 y=-0.03 0.13 MU6 multiport diffuser discharge in ;
z=0.98 z=0.26 uniform layer
Ambient Water Depth x=8.1 x=0.06 Submerged positively buoyant �
Max 3.84 0.097 y=-2.11 47 0.14 35 0.14 35.7 2 y=-0.02 0.10 MU6 multiport diffuser discharge in
z=1.62 z=0.26 uniform layer • ..
x=6.55 x=0.05 Submerged positively buoyant !�.--.
Ambient Wind Min 3.84 0.097 y=-2.60 38 0.17 29.3 0.16 30.3 2 y=-0.02 0.11 MU6 multiport diffuser discharge in
z=1.31 z=0.26 uniform layer
x=6.55 x=0.05 Submerged positively buoyant (.�h8J5.._
Ambient Wind Max 3.84 0.097 y=-2.60 38 0.17 29.3 0.16 30.6 2 y=-0.02 0.05 MU6 multiport diffuser discharge in ti
4 z=1.31 z=0.26 uniform layer -_tzIpi
trrLi x=6.55 x=0.06 Submerged positively buoyant (-aJ0
a Ambient Current
Z Speed 1 Hr(SO%) 3.84 0.097 y=-10.42 76 0.25 19.8 0.23 21.4 2 y=-0.09 0.19 MU6 multiport diffuser discharge in _.1......,,,9
z=1.31 z=0.26 uniform layer _.1......,,,
Ambient Current x=6.55 x=0.06 Submerged positively buoyant ii._/,tnf. '
Speed 1 Mr(75%) 3.84 0.097 y=-4.63 51 0.21 121.6 0.20 25.6 2 y=-0.04 0.15 MU6 multiport diffuser discharge in _f
z=1.31 z=0.26 uniform layer i " .
z x=6.55 x=0.05 Submerged positively buoyant -Li,-°--
ti Ambient Current 3.84 0.097 y=-1.67 30 0.14 34.6 0.14 35.3 2 y=-0.01 0.07 MU6 multiport diffuser discharge in
Speed 1 Hr(125%) z=1.31 z=0.26 uniform layer
Ambient Current x=6.55 x=0.05 Submerged positively buoyant . !1'`
Speed 1 Hr urrent 3.84 0.097 y=-0.65 19 0.10 51.2 0.10 51.6 2 y=0 0.05 MU6 multiport diffuser discharge in
(200z=1.31 z=0.26 uniform layer ..__-_•
_..
Deeply submerged negatively
x=6.55 x=0.05 buoyant multiport diffuser discharge -
Ambient Density Low 3.84 -0.056 y=-2.60 38 0.17 29.3 0.17 30.0 2 y=-0.02 0.11 MNU11 in uniform layer with a strong
z=0 z=0.26 J
current
x=6.55 x=0.05 Submerged positively buoyant I W6_ I
Ambient Density High 3.84 0.219 y=-2.60 38 0.17 29.3 0.16 31.0 2 y=-0.02 0.11 MU6 multiport diffuser discharge in -
z=1.31 z=0.26 uniform layer
c v x=6.55 x=0.05 Submerged positively buoyant I1
o 3 = Initial Effluent Vol 1.92 0.097 y=-0.65 38 0.10 51.8 0.09 53.0 2 y=0 0.06 MU6 multiport diffuser discharge in
W-u z=1.31 z=0.26 uniform layer r
Deeply submerged negatively
x=6.55 x=0.051
A" MULTI 6 SALTIER 3.84 -0.076 y=-2.61 38 0.17 29.3 0.17 30.1 2 y=-0.02 0.11 MNUll buoyant multiport diffuser discharge
g c z=0 z=0.26 in uniform layer with a strong -• ,-�`
c'3 current
N
x=6.55 x=0.05 Submerged positively buoyant w
n MULTI
A 3 MCHA 3.84 0174 y=-2.61 38 0.17 29.3 0.16 30.8 2 y=-0.02 0.11 MU6 multiport diffuser discharge in yt _
j z=1.31 z=0.26 uniform layer v
'Sensitivity Analyses performed on the MULTI 6 discharge configuration.
The final optimized multiport diffuser design used as the base for all sensitivity analyses is shaded orange.
page 2 of 2

Table 9. Multi-port Simulation Variables for the Proposed BBWC RO Discharge,Carteret County, NC(GMA Project #: 24312)
Multi-Port Variables
Distance Distance to Diffuser Diffuser
Simulation Diffuser Diffuser to 1st 2nd Nozzle Nozzle Port Port Total Alignment Relative
Name Length Length Endpoint Endpoint Spacing Spacing Height Diameter Contraction Number of Angle Vertical Horizontal Orientation
(feet) (meters) (meters) (meters) (feet) (meters) (meters) (inches) Ratio Openings Gamma Theta Sigma Beta
MULTI 1 30 9.144 105 114.144 10 3.05 0.254 4.0 1 4 90 5 90 0
MULTI 2 30 9.144 105 114.144 10 3.05 0.254 3.0 1 4 90 5 90 0
MULTI 3 30 9.144 105 114.144 10 3.05 0.254 2.0 1 4 90 5 90 0
MULTI 4 20 6.096 105 111.096 6.7 2.07 0.254 3.0 1 4 90 5 90 0
MULTI 5 10 3.048 105 108.048 3.3 1.006 0.254 3.0 1 4 90 5 90 0
MULTI 6 _ 20 6.096 105 111.096 6.7 2.07 0.254 3.0 1 3 90 5 90 0
Bold indicates a variable being altered to determine effect on mixing. Green indicates an optimized variable based on previous simulations.

APPENDIX I
PHOTOGRAPHS

Appendix I. Photographs. Bogue Banks Water Corporation, Carteret County, North Carolina (GMA Project#24312)
. ,_. - - — -
- .fin
�, ' i
._ n'h 1
Oct 20,201/
ACM-Plus current meter attached to anchoring base Current-meter station buoy
r :
x
I
111111P
•
OCt2. Oct 20.2017
Rope setup used for current meter retrieval Staff gauge set-up

Appendix I. Photographs. Bogue Banks Water Corporation, Carteet County, North Carolina (GMA Project#24312)
9
Benthic grab sample and LaMotte sampling dredge Benthic grab sample
•
•
ilia 11;00
•
-Zt 20 2017
ct20.2017
Using a sieve to prepare a benthic
macroinvertebrate sample for Looking west towards current meter
station
identification

Appendix I. Photographs. Bogue Banks Water Corporation, Carteret County, North Carolina (GMA Project#24312)
•
•
dry' ,.a.
k. Jj
oct 20
Oct 20,2017
Preparing to attach temporary staff
View looking northwest from current
gauge
meter station towards staff gauge
r., a-° r._ :. •. W
11111111111
11104
4 _„eOe!20.2017
Collecting field notes Anchoring retrieval line to current meter.
Line was sunk to avoid boat

Appendix I. Photographs. Bogue Banks Water Corporation, Carteret County, North Carolina (GMA Project#24312)
t:
otiolootH„ 4.10i, ,,,i
10111
_ ,...... _ _
.........._ .....
ii _ ., ,....._ __
__ _
_ _A5,_
ir .
1 7w� G N.
Oct 20,2017
Attaching current meter retrieval line View looking west from center of channel
v.
,
t
i yam _
r lde.! .
, Oct20,2017 °..
Bogue Banks Water Corporation staff operating vessel
used for current meter deployment Staff Gauge

APPENDIX II
METEOROLOGICAL DATA FROM THE KNJM WEATHER STATION
III

Appendix II. KNJM Weather Station Bogue Banks Water Corporation
Carteret County, North Carolina (GMA Project#24312)
Date and Time Temperature (F) Wind Direction Wind Speed Precip (In)
(Degrees) (MPH)
10/19/2017 0:57 60.1 North (100) 10.4 -
10/19/2017 1:57 59 North (10°) 9.2 -
10/19/2017 2:57 59 North (10°) 9.2 -
10/19/2017 3:57 60.1 North (10°) 10.4 -
10/19/2017 4:57 60.1 North (10°) 9.2 -
10/19/2017 5:57 60.1 North (10°) 9.2 -
10/19/2017 6:57 60.1 North Northeast (20°) 9.2 -
10/19/2017 7:57 64 North Northeast (20°) 6.9 -
10/19/2017 8:57 70 Northeast (40°) 8.1 -
10/19/2017 9:57 73.9 East Northeast (70°) 9.2 -
10/19/2017 10:57 77 North Northeast (30°) 8.1 -
10/19/2017 11:57 77 Calm or Variable 4.6 -
10/19/2017 12:57 77 Southeast (130°) 6.9 -
10/19/2017 13:57 77 Southeast (130°) 5.8 -
10/19/2017 14:57 73.9 South Southwest (200°) 8.1 -
10/19/2017 15:57 73.9 Southeast (130°) 6.9 -
10/19/2017 16:57 72 Calm or Variable 5.8 -
10/19/2017 17:57 66 Calm or Variable 0 -
10/19/2017 18:57 64 Calm or Variable 0 -
10/19/2017 19:57 62.1 Northwest (310°) 3.5 -
10/19/2017 20:57 60.1 Calm or Variable 0 -
10/19/2017 21:57 59 Calm or Variable 0 -
10/19/2017 22:57 57.9 Calm or Variable 0 -
10/19/2017 23:57 57.9 Calm or Variable 0 -
10/20/2017 0:57 57 Calm or Variable 0 -
10/20/2017 1:57 55 Calm or Variable 0 -
10/20/2017 2:57 55.9 Calm or Variable 0 -
10/20/2017 3:57 55 Calm or Variable 0 -
10/20/2017 4:57 54 Calm or Variable 0
10/20/2017 5:57 53.1 Calm or Variable 0 -
10/20/2017 6:57 55 North Northwest (340°) 4.6 -
10/20/2017 7:57 61 North Northwest (330°) 3.5 -
10/20/2017 8:57 66.9 Calm or Variable 4.6 -
10/20/2017 9:57 71.1 Calm or Variable 6.9 -
10/20/2017 10:57 73.9 West Northwest (290°) 5.8 -
10/20/2017 11:57 75 Calm or Variable 3.5 -
10/20/2017 12:57 77 Calm or Variable 3.5 -
10/20/2017 13:57 75.9 South (190°) 6.9 -
10/20/2017 14:57 75 South Southeast (160°) 6.9 -
10/20/2017 15:57 73 South Southwest (210°) 6.9 -
10/20/2017 16:57 71.1 South Southwest (210°) 3.5 -
10/20/2017 17:57 64 Calm or Variable 0 -
10/20/2017 18:57 61 Calm or Variable 0 -
1 of 5

Date and Time Temperature (F) Wind Direction Wind Speed Precip (In)
(Degrees) (MPH)
10/20/2017 19:57 60.1 Calm or Variable 0 -
10/20/2017 20:57 59 Calm or Variable 0 -
10/20/2017 21:57 57 Calm or Variable 0 -
10/20/2017 22:57 55.9 Calm or Variable 0 -
10/20/2017 23:57 55 Calm or Variable 0 -
10/21/2017 0:57 55 Calm or Variable 0 -
10/21/2017 1:57 53.1 Calm or Variable 0 -
10/21/2017 2:57 53.1 Calm or Variable 0 -
10/21/2017 3:57 53.1 Calm or Variable 0 -
10/21/2017 4:57 52 Calm or Variable 0 -
10/21/2017 5:57 52 Calm or Variable 0 -
10/21/2017 6:57 53.1 Calm or Variable 0 -
10/21/2017 7:57 64 North Northeast (20°) 3.5 -
10/21/2017 8:57 71.1 Northeast (40°) 4.6 -
10/21/2017 9:57 73.9 East Northeast (60°) 6.9 -
10/21/2017 10:57 75.9 East Southeast (110°) 5.8 -
10/21/2017 11:57 75.9 East (100°) 8.1 -
10/21/2017 12:57 77 East (100°) 5.8 -
10/21/2017 13:57 75.9 South Southeast (150°) 5.8 -
10/21/2017 14:57 75 South (170°) 5.8 -
10/21/2017 15:57 73.9 Southeast (130°) 5.8 -
10/21/2017 16:57 71.1 East Southeast (120°) 3.5 -
10/21/2017 17:57 70 East Northeast (70°) 3.5 -
10/21/2017 18:57 66 Calm or Variable 0 -
10/21/2017 19:57 63 Calm or Variable 0 -
10/21/2017 20:57 61 Calm or Variable 0 -
10/21/2017 21:57 62.1 Northeast (50°) 4.6 -
10/21/2017 22:57 60.1 Northeast (50°) 3.5 -
10/21/2017 23:57 61 North Northeast (30°) 4.6 -
10/22/2017 0:57 57.9 Northeast (40°) 3.5 -
10/22/2017 1:57 62.1 Northeast (40°) 5.8 -
10/22/2017 2:57 62.1 North Northeast (20°) 4.6 -
10/22/2017 3:57 62.1 North Northeast (30°) 5.8 -
10/22/2017 4:57 63 North Northeast (20°) 6.9 -
10/22/2017 5:57 62.1 North Northeast (20°) 5.8 -
10/22/2017 6:57 63 North Northeast (30°) 4.6 -
10/22/2017 7:57 66.9 North Northeast (20°) 8.1 -
10/22/2017 8:57 72 North Northeast (30°) 5.8 -
1 10/22/2017 9:57 75 Northeast (40°) 8.1 -
1 10/22/2017 10:57 79 East Northeast (70°) 6.9 -
10/22/2017 11:57 78.1 East (100°) 9.2 -
10/23/2017 8:57 77 South Southeast (150°) 10.4 -
10/23/2017 9:57 78.1 South Southeast (150°) 13.8 -
10/23/2017 10:57 79 South Southeast (150°) 11.5 -
10/23/2017 11:57 78.1 South Southeast (160°) 12.7 -
2 of 5

Date and Time Temperature (F) Wind Direction Wind Speed Precip (In)
(Degrees) (MPH)
10/23/2017 12:57 79 South (1801 16.1 -
10/23/2017 13:57 78.1 South (170°) 9.2 -
10/23/2017 14:57 77 South Southeast (150°) 12.7 -
10/23/2017 15:57 73 South (170°) 23 0.0001
10/23/2017 16:57 72 South Southeast (160°) 17.3 0.02
10/23/2017 17:57 75 South (170°) 16.1 0.0001
10/23/2017 18:57 75 South (170°) 16.1 -
10/23/2017 19:57 75.9 South (170°) 21.9 -
10/23/2017 20:57 75.9 South (180°) 24.2 -
10/23/2017 21:57 75.9 South (180°) 21.9 0.0001
10/23/2017 22:57 75.9 South (180°) 25.3 0.0001
10/23/2017 23:57 75 South (180°) 18.4 0.06
10/24/2017 0:57 73.9 South (170°) 23 0.12
10/24/2017 1:57 72 South (170°) 18.4 0.22
10/24/2017 3:57 66 West Northwest (300°) 3.5 0.06
10/24/2017 4:57 64.9 West Northwest (290°) 4.6 0.03
10/24/2017 5:57 64.9 Calm or Variable 0 0.1
10/24/2017 6:57 68 South (170°) 8.1 0.04
10/24/2017 7:57 71.1 South (170°) 11.5 -
10/24/2017 8:57 73 South (190°) 12.7 -
10/24/2017 9:57 75 South Southwest (200°) 10.4 -
10/24/2017 12:57 77 Southwest (220°) 16.1 -
10/24/2017 13:57 78.1 South Southwest (210°) 13.8 -
10/24/2017 14:57 75.9 Southwest (230°) 13.8 -
10/24/2017 15:57 75 West Southwest (240°) 15 -
10/24/2017 16:57 73 Southwest (230°) 10.4 -
10/24/2017 17:57 72 West Southwest (250°) 5.8 -
10/24/2017 18:57 70 West Southwest (240°) 5.8 -
10/24/2017 19:57 69.1 West (280°) 3.5 -
10/24/2017 20:57 68 West (270°) 8.1 -
10/24/2017 21:57 66 West (260°) 6.9 -
10/24/2017 22:57 64 West (270°) 4.6 -
10/24/2017 23:57 64 West (280°) 5.8 -
10/25/2017 0:57 62.1 Calm or Variable 4.6 -
10/25/2017 1:57 61 West Northwest (290°) 8.1 -
10/25/2017 2:57 60.1 Northwest (310°) 4.6 -
10/25/2017 3:57 57.9 Northwest (320°) 3.5 -
10/25/2017 4:57 55.9 West Northwest (290°) 4.6 -
10/25/2017 5:57 55.9 Northwest (320°) 5.8 -
10/25/2017 6:57 55.9 Northwest (320°) 5.8 -
10/25/2017 7:57 57 North Northwest (330°) 5.8 -
10/25/2017 8:57 61 North Northwest (330°) 5.8 -
10/25/2017 9:57 63 Northwest (310°) 4.6 -
10/25/2017 10:57 64.9 West Southwest (240°) 4.6 -
10/25/2017 11:57 66.9 Southwest (230°) 8.1 -
3 of 5

I
Date and Time Temperature (F) Wind Direction Wind Speed Precip (In)
(Degrees) (MPH)
10/25/2017 12:57 66.9 Southwest (2301 11.5 -
10/25/2017 13:57 66 West Northwest (290°) 4.6 -
10/25/2017 14:57 68 North Northwest (330°) 6.9 -
10/25/2017 15:57 66 Northwest (310°) 3.5 -
10/25/2017 16:57 64 West Northwest (300°) 3.5 -
10/25/2017 17:57 57.9 West Northwest (300°) 3.5 -
10/25/2017 18:57 55 West Northwest (300°) 3.5 -
10/25/2017 19:57 53.1 Northwest (310°) 3.5 -
10/25/2017 20:57 50 Northwest (310°) 3.5 -
10/25/2017 21:57 52 Northwest (310°) 4.6 -
10/25/2017 22:57 54 Northwest (310°) 3.5 -
10/25/2017 23:57 51.1 West Northwest (300°) 5.8 -
10/26/2017 0:57 51.1 Northwest (3101 5.8 -
10/26/2017 1:57 48.9 North Northwest (330°) 5.8 -
10/26/2017 2:57 48.9 Northwest (320°) 6.9
10/26/2017 3:57 50 Northwest (310°) 10.4 -
10/26/2017 4:57 48.9 North Northwest (330°) 6.9 -
10/26/2017 5:57 48.9 Northwest (320°) 9.2 -
10/26/2017 6:57 48.9 Northwest (310°) 8.1 -
10/26/2017 7:57 52 Northwest (320°) 10.4 -
10/26/2017 8:57 52 Northwest (310°) 6.9 -
10/26/2017 9:57 57 Northwest (320°) 11.5 -
10/26/2017 10:57 59 Northwest (320°) 13.8 -
10/26/2017 11:57 60.1 West Northwest (300°) 9.2 -
10/26/2017 12:57 62.1 Northwest (320°) 9.2 -
10/26/2017 13:57 63 North Northwest (330°) 9.2 -
10/26/2017 14:57 63 Northwest (310°) 9.2 -
10/26/2017 15:57 63 West Northwest (300°) 6.9 -
10/26/2017 16:57 59 Northwest (310°) 3.5 -
10/26/2017 17:57 51.1 West Northwest (300°) 3.5 -
10/26/2017 18:57 48.9 Calm or Variable 0 -
10/26/2017 19:57 46.9 Calm or Variable 0 -
10/26/2017 20:57 46.9 Calm or Variable 0 -
10/26/2017 21:57 45 Calm or Variable 0 -
10/26/2017 22:57 44.1 Calm or Variable 0 -
10/26/2017 23:57 42.1 Calm or Variable 0 -
10/27/2017 0:57 44.1 Calm or Variable 0 -
10/27/2017 1:57 41 Calm or Variable 0 -
10/27/2017 2:57 42.1 Calm or Variable 0 -
10/27/2017 3:57 41 Calm or Variable 0 -
10/27/2017 4:57 39.9 Calm or Variable 0 -
10/27/2017 5:57 39 Calm or Variable 0 -
10/27/2017 6:57 41 Calm or Variable 0 -
10/27/2017 7:57 51.1 Calm or Variable 0 -
10/27/2017 8:57 61 Calm or Variable 0 -
4 of 5

Date and Time Temperature (F) Wind Direction Wind Speed Precip (In)
(Degrees) (MPH)
10/27/2017 9:57 64 Southeast (1401 4.6 -
10/27/2017 10:57 66 East Southeast (120°) 6.9 -
10/27/2017 11:57 66 Calm or Variable 5.8 -
10/27/2017 12:57 66.9 South Southeast (150°) 8.1 -
10/27/2017 13:57 66 South (170°) 6.9 -
10/27/2017 14:57 66 South Southeast (150°) 6.9 -
10/27/2017 15:57 66 Southeast (140°) 6.9 -
10/27/2017 16:57 63 South (180°) 4.6 -
10/27/2017 17:57 55.9 Calm or Variable 0 -
10/27/2017 18:57 53.1 Calm or Variable 0 -
10/27/2017 19:57 54 Calm or Variable 0 -
10/27/2017 20:57 54 Calm or Variable 0 -
10/27/2017 21:57 51.1 Calm or Variable 0 -
10/27/2017 22:57 50 Calm or Variable 0 -
10/27/2017 23:57 50 Calm or Variable 0 -
10/28/2017 0:57 50 Calm or Variable 0 -
10/28/2017 1:57 52 Calm or Variable 0 -
10/28/2017 2:57 53.1 Calm or Variable 0 -
10/28/2017 3:57 55.9 East Northeast (60°) 3.5 -
10/28/2017 4:57 55.9 Calm or Variable 0 -
10/28/2017 5:57 55.9 North (10°) 3.5 -
10/28/2017 6:57 57 Northeast (40°) 4.6 -
10/28/2017 7:57 60.1 East Northeast (60°) 4.6 -
10/28/2017 8:57 63 Calm or Variable 3.5 -
10/28/2017 9:57 66 East (90°) 8.1 -
10/28/2017 10:57 69.1 East (100°) 8.1 -
10/28/2017 11:57 71.1 East (100°) 8.1 -
10/28/2017 12:57 73 East (100°) 8.1 -
10/28/2017 13:57 75 East (100°) 5.8 -
10/28/2017 14:57 75.9 Southeast (130°) 6.9 -
10/28/2017 15:57 75 South (170°) 6.9 -
10/28/2017 16:57 71.1 East (100°) 3.5 -
10/28/2017 17:57 72 South (180°) 8.1 -
10/28/2017 18:57 72 South Southeast (160°) 5.8 -
10/28/2017 19:57 73 South (170°) 6.9 -
10/28/2017 20:57 73.9 South (170°) 10.4 -
10/28/2017 21:57 73.9 South (190°) 10.4 -
10/28/2017 22:57 73.9 South (170°) 10.4 -
10/28/2017 23:57 73.9 South (170°) 11.5 -
5of5

APPENDIX III
TIDAL PREDICTIONS FROM NOAA TIDAL STATION
TEC2837 AT BOGUE INLET

Appendix III. Tidal Predictions from NOAA Tidal Station TEC2837 at Bogue Inlet
Bogue Banks Water Corporation, Carteret County, North Carolina, (GMA Project#24312)
Date Day of the Week Time (LST/LDT) Predicted (ft) High/Low
10/20/2017 Fri 14:54 0.14 L
10/20/2017 Fri 20:51 2.43 H
10/21/2017 Sat 2:52 0.18 L
10/21/2017 Sat 9:11 2.82 H
10/21/2017 Sat 15:35 0.22 L
10/21/2017 Sat 21:30 2.32 H
10/22/2017 Sun 3:28 0.27 L
10/22/2017 Sun 9:49 2.76 H
10/22/2017 Sun 16:16 0.32 L
10/22/2017 Sun 22:08 2.19 H
10/23/2017 Mon 4:04 0.38 L
10/23/2017 Mon 10:28 2.67 H
10/23/2017 Mon 16:58 0.44 L
10/23/2017 Mon 22:48 2.07 H
10/24/2017 Tue 4:42 0.5 L
10/24/2017 Tue 11:09 2.56 H
10/24/2017 Tue 17:42 0.57 L
10/24/2017 Tue 23:31 1.96 H
10/25/2017 Wed 5:24 0.62 L
10/25/2017 Wed 11:54 2.45 H
10/25/2017 Wed 18:30 0.67 L
10/26/2017 Thu 0:18 1.87 H
10/26/2017 Thu 6:11 0.71 L
10/26/2017 Thu 12:43 2.36 H
10/26/2017 Thu 19:23 0.74 L
10/27/2017 Fri 1:12 1.83 H
10/27/2017 Fri 7:05 0.78 L
10/27/2017 Fri 13:38 2.29 H
10/27/2017 Fri 20:18 0.75 L

APPENDIX IV
LABORATORY ANALYTICAL RESULTS

Environmental Chemists, Inc.
envirochenl 6602 Windmill Way,Wilmington,NC 28405 • 910.392.0223 Lab • 910.392.4424 Fax
710 Bowsertown Road,Manteo,NC 27954 • 252.473.5702 Lab/Fax
SM) 255-A Wilmington Highway,Jacksonville,NC 28540 • 910.347.5843 Lab/Fax
ANALYTICAL&CONSULTING CHEMISTS [e-mail]
Groundwater Management Associates Date of Report: Oct 30, 2017
4300 Sapphire Ct, Suite 100 Customer PO#:
Greenville NC 27834 Customer ID: 09030031
Attention: Jay Holley Report#: 2017-16392
Project ID: 24312
Lab ID Sample ID: High Tide Collect Date/Time Matrix Sampled by
17-39618 Site: 10/20/2017 10:20 AM Water Emma Shipley
Test Method Results Date Analyzed
Ammonia Nitrogen EPA 350.1 0.3 mg/L 10/25/2017
Total Kjeldahl Nitrogen (TKN) EPA 351.2 0.7 mg/L 10/26/2017
Total Dissolved Solids (TDS) SM 2540 C 38000 mg/L 10/23/2017
Chloride SM 4500 CI E 12900 mg/L 10/27/2017
Total Phosphorus SM 4500 P F 0.08 mg/L 10/27/2017
Total Nitrogen Total Nitrogen 0.7 mg/L 10/28/2017
Total Nitrogen (Calc)
Nitrate+Nitrite-Nitrogen EPA 353.2 < 0.02 mg/L 10/26/2017
Lab ID Sample ID: Low Tide Collect Date/Time Matrix Sampled by
17-39619 Site: 10/20/2017 1:25 PM Water Emma Shipley
Test Method Results Date Analyzed
Ammonia Nitrogen EPA 350.1 < 0.2 mg/L 10/25/2017
Total Kjeldahl Nitrogen (TKN) EPA 351.2 0.7 mg/L 10/26/2017
Total Dissolved Solids (TDS) SM 2540 C 37000 mg/L 10/23/2017
Chloride SM 4500 CI E 14200 mg/L 10/27/2017
Total Phosphorus SM 4500 P F 0.10 mg/L 10/27/2017
Total Nitrogen Total Nitrogen 0.7 mg/L 10/28/2017
Total Nitrogen (Calc)
Nitrate+Nitrite-Nitrogen EPA 353.2 < 0.02 mg/L 10/26/2017
Comment:Reviewed by: —7 1 /I-1--
Report#:. 2017-16392 Page 1 of 1

envirnchem ENVIRONMENTAL 602 Windmill Way Wilmington,NC 28405
L CHEMISTS, INCI N C OFFICE: 910-392-0223 FAX [phone]
Analytical&Consulting Chemists NCDENR: DWQ CERTIFICATION#94 NCDHHS: DLS CERTIFICATION#37729 [e-mail]
COLLECTION AND CHAIN OF CUSTODY
CLIENT: 6, (Y,/ PROJECT NAME: -�
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J? , REPORT NO: I� 3� �-
ADDRESS: 1-{2, y1tt e . ` F�7�.-e. CONTACT NAME: a.41 . t�( PO NO: 2._L1' i 2-
E-A4 .\A u N(. 2.--n ;6.; REPORT TO: .,j01.+j kL 1\M' +CA1(c TV\C.4-rlc .c.all PHONE/FAX: -? 4y 7... •Th : I -'
COPY TO: -0. Y\t V e;1 Vvy , ?(rah t TIO _O' (,ti, email:
Sampled By: IZ;,mob, , cK,,l )e•j SAMPLE TYPE: I=Influent, E= Effluent, W=Well,ST=Stream,SO=Soil, SL= Sludge, Other:
Collection m
c c2 o Q PRESERVATION
Sample Identification a a g - t; m
1 E ° 6 = °o et- t E a z 3 o 00 ANALYSIS REQUESTED
Date Time Temp " J Z ° _ _ _`
N
i 01 I-0 a 10 ' 2.0 C P ,,ci os'viS t
l t t�b, j ( (0�` TDS C�ft{or�cl� , tOk t' f_' `
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I—CAN i ) u , . CT (G) G ,��LO 9 X/ kU r ice, 4v f ha Spiwa...�S} ff m,.,
C P
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•
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G G
C P
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Transfer Relinquished By: Date/Time Received y: Date/Time
1. ./,/,e4. cam?. v J
(b. 23 � 7 /2 l 8 , t0 -23 0 7.7 i
2. /
Temperature when Received: f.' `r' Accepted: N.s' ejected: Resample Requested:
Delivered By: Received By. . V 'Y tom QA, k-A-- Date: / 'LL 2.3 Time: l/q 8'
Comments: P TURNAROUND:

APPENDIX V
BENTHIC MACROINVERTEBRATE ANALYSES

Excellence In Any Environment
Ms. Emma Shipley
Groundwater Management Associates, Inc
Ms. Shipley,
The macroinvertebrates identified from the Bogue Banks Flow Study are detailed in the table
below. The water quality data provided, dated 10/20/17, are within normal parameters for this
type of habitat. Temperature, dissolved oxygen, and pH are all normal. Estimated salinity can
range from 12-30 in estuary habitats and the estimated values provided were not unusual.
Organisms BM-1 BM-2 BM-3 BM-4 BM-5 BM-6
Ostracoda 1 1
Mediomastus sp. 4 17 4 8 2 4
Streblospio benedicti 1 5 12 9 6 18
Undertermined Spionidae 1
Glycera sp. 1
Arabella iricolor 1 1
Eteone sp. 1
Capitella sp. 1
Maldanidae 1
Ampelisca sp. 1 1
Leptocheirus sp. 1 1
Mulinia lateralis 1
TOTALS 7 25 21 18 10 23
Please let me know if you have any additional questions.
Sincerely,
Nicole Jordan
Aquatic Biologist
EnviroScience
5070 Stow Road
Stow, OH 44224
Toll Free:800-940-4025 I Office:330-688-0111 I Fax:[phone]

APPENDIX VI
GRAIN SIZE ANALYSES

Particle Size Distribution Report
C O O O
C 4 I O O O O I C O V O
CO el N w ��" P�7 . 5 N # # # # # #
100 I I
I I •
I I
90
I
1
I
80 1
70 r
1 1
1 1
1 I
(r
W 60 r
z
LI
z 50
W
0
w 40 I
I
1 I •
1
1
30 + + I + I I 1
I I I
I I
I I
1
20 l 1 1-
I
• • • •
10 •
1
1
0_i___ i
100 10 1 0.1 0.01 0.001
GRAIN SIZE-mm.
�/,+3" %Gravel %Sand %Fines
Coarse Fine Coarse 1 Medium Fine Silt Clay
0.0 0.0 0.0 0.0 1.2 84.2 3.7 10.9
SIEVE PERCENT SPEC.* PASS? Material Description
SIZE FINER PERCENT (X=NO) GRAY SILTY FINE SAND
#4 100.0
#10 100.0
#20 99.7 Atterberg Limits
#40 98.8 PL= LL= Pi=
#60 93.6
#100 34.3 Coefficients
#200 14.6 D90= 0.2394 D85= 0.2275 D60= 0.1858
D50= 0.1721 D30= 0.1346 D15= 0.0770
D10= 0.0035 Cu— 53.29 Cc— 27.96
Classification
USCS= SM AASHTO= A-2-4(0)
Remarks
(no specification provided)
Location: Project#24312(Bogue Banks Flow Study)
Sample Number: GS-1 Date: 11-1-17
Te rra c o n Consultants, Inc. Client: Groundwater Management Associates,Inc
Project: Lab Testing for Groundwater Management Associates
Various Locations,NC
Winterville, North Carolina Project No: 72101159 Figure GS-1
Tested By: LWest Checked By: BNeel

Particle Size Distribution Report
C C C O O O O O O_ V O
t0 C. CVw elit V •_ it # # ik it
100 I 1
I
I
I •
I
I
90 I
I
1
I
I
80
I
I
1
70
1
1
I
LLJ_z 60
LL
z 50
w
U
GC
w 40 a .
o_
1 1
1
30
• I
I I I
1
20 }
1 I
it
1 1'
1
10 • • • •
0
100 10 1 0.1 0.01 0.001
GRAIN SIZE- mm.
%+3„ %Gravel %Sand %Fines
Coarse Fine Coarse Medium Fine Silt Clay
0.0 0.0 0.0 0.0 0.1 91.2 4.2 4.5
SIEVE PERCENT I SPEC.* PASS? Material Description
SIZE FINER PERCENT (X=NO) GRAY FINE SAND W/SILT
#4 100.0
#10 100.0
#40 100.0 Atterberg Limits
#40 99.9 PL= LL= PI=
#60 95.3
#100 28.5 Coefficients
#200 8.7 D90= 0.2363 D85= 0.2262 D60= 0.1891
D50= 0.1768 D30= 0.1521 015= 0.1013
D10= 0.0812 Cu— 2.33 Cc= 1.51
Classification
I USCS= SP-SM AASHTO= A-3
Remarks
* (no specification provided)
Location: Project#24312(Bogue Banks Flow Study)
Sample Number:GS-2 Date: 11-1-17
Terracon Consultants, Inc. Client: Groundwater Management Associates,Inc
Project: Lab Testing for Groundwater Management Associates
Various Locations,NC
Winterville, North Carolina Project No: 72101159 Figure GS-2
Tested By: LWest Checked By: BNeel

Particle Size Distribution Report
c c 0 0 0
0 0 0 0 0_ 0
CD 1) N Wk. 8- yt a • • # # ik It 00 I
I
I
I I I
90 I
80
70 1
1
I
I
W I
W 60
Z
Li
I—
z 50
LL
U
w 40
I I I I
I I
I I
I 1
I I I I I • i
30 -
I I
I I
I I
20 i � I
\
10 1 II
"•MPF11111111111■ •
0
100 10 1 0.1 0.01 0.001
GRAIN SIZE- mm.
+3" %Gravel %Sand _ %Fines
% Coarse Fine Coarse Medium Fine Silt _ Clay
0.0 0.0 (1.0 0.0 0.2 89.I 4.3 6.4
SIEVE PERCENT SPEC.* PASS? Material Description
SIZE FINER PERCENT (X=NO) GRAY FINE SAND W/SILT
#4 100.0
#10 100.0
#20 100.0
#40 99.8 Atterberg Limits
#60 95.6 PL= LL= PI=
#100 31.2 Coefficients
#200 10.7 D90= 0.2351 D85= 0.2248 D60= 0.1869
D50= 0.1743 D30= 0.1459 D15= 0.0927
D10= 0.0524 Cu- 3.56 Cc- 2.17
Classification
USCS= SP-SM AASHTO= A-2-4(0) 1
Remarks
* (no specification provided)
Location: Project#24312(Bogue Banks Flow Study)
Sample Number: GS-3 Date: 11-1-17
Terracon Consultants, Inc. Client: Groundwater Management Associates,Inc
Project: Lab Testing for Groundwater Management Associates
Various Locations,NC
Winterville, North Carolina Project No: 72101159 Figure GS-3
Tested By: LWest Checked By: BNeel

Particle Size Distribution Report
o _oo
c c c c ._' E ., o 0 0 0 2 o a o
t0 C�) N .- w C7 �k _# • # # # #
100 1 �l I I
I I
I I I •
I
90 I I •
I
1
1
I
1
80
I
1
1
70 1 I
I
W 60
Z_
LI
Z 50
w
0
W 40 I I I
I I I
I I
I
30 '
1 1
I 1 1
1 I 1
1 I 1
1 1 1
20 + L I J.
1 1
10
• • •
• : c —0
0
100 10 1 0.1 0.01 0.001
GRAIN SIZE- mm.
%+3„ %Gravel %Sand %Fines
Coarse Fine Coarse Medium Fine Silt Clay
0.0 0.0 0.0 0.0 0.2 92.1 3.6 4.1
SIEVE PERCENT SPEC.* PASS? Material Description
SIZE FINER PERCENT (X=NO) GRAY FINE SAND W/SILT
#4 100.0
#10 100.0
#20 100.0 Atterberg Limits
#40 99.8 PL= LL= P1=
#60 94.0
#100 30.8 Coefficients
#200 7.7 D90= 0.2389 D85= 0.2277 D60= 0.1881
D50= 0.1750 D30= 0.1475 D15= 0.1013
D10= 0.0842 Cu- 2.23 Cc- 1.38
Classification
USCS= SP-SM AASHTO= A-3
Remarks
* (no specification provided)
Location: Project#24312(Bogue Banks Flow Study)
Sample Number: GS-4 Date: 1 1-2-17
Terracon Consultants, Inc. Client: Groundwater Management Associates,Inc
Project: Lab Testing for Groundwater Management Associates
Various Locations,NC
Winterville, North Carolina Project No: 72101159 Figure GS-4
Tested By: LWest Checked By: BNeel

Particle Size Distribution Report
C C - O O O O O 0 O
o co C c C O aao
c N 0., V (O N
100 1
I I
I I I
I I
00 I I I
I
1
I
80
7 1
1 I
I II
70 r
I1
W 60
ZLZ 50
WUW 40
+
a 1
30 II H \ IL
II III 11
10 1
1
�C`4 0
0
100 10 1 0.1 0.01 0.001
GRAIN SIZE- mm.
+3" %Gravel %Sand %Fines
% Coarse _ Fine Coarse Medium Fine Silt Clay
0.0 0.0 0.0 0.0 0.2 92.8 3.0 4.0
SIEVE PERCENT SPEC.* PASS? Material Description
SIZE FINER PERCENT (X=NO) GRAY FINE SAND W/SILT
#4 100.0
#10 100.0
#20 100.0 Atterberg Limits
#40 99.8PL= LL= PI=
#60 94.6
#100 28.4 Coefficients
#200 7.0 D90= 0.2379 D85= 0.2274 D60= 0.1895
D50= 0.1770 D30= 0.1522 D15= 0.1059
D10= 0.0878 CU= 2.16 Cc- 1.39
Classification
USCS= SP-SM AASHTO= A-3
Remarks
* (no specification provided)
Location: Project#24312(Bogue Banks Flow Study)
Sample Number:GS-5 Date: I 1-2-17
Terracon Consultants, Inc. Client: Groundwater Management Associates,Inc
Project: Lab Testing for Groundwater Management Associates
Various Locations,NC
Winterville, North Carolina I Project No: 72101159 Figure GS-5
Tested By: LWest Checked By: BNeel

APPENDIX VII
DWQ MIXING ZONE RULE
I

MIXING ZONES IN NORTH CAROLINA
July 23, 1999
A mixing zone is an area downstream of a discharge point where the effluent is diluted by
the receiving water and within which certain water quality standards that would otherwise be
applicable may be exceeded. Under North Carolina regulations, mixing zones can be established on
a case by case basis. This document summarizes North Carolina's mixing zone rule and describes
how it has been used to establish mixing zones.
Standard Permitting Procedure
The following paragraphs provide a brief summary of the Division of Water Quality's
standard operating procedures for determining dilution and establishing permit limits for toxicants.
Further details on permitting procedures may be found in the Division's Wasteload Allocation
Standard Operating Procedures Manual and in the NPDES Permit Writer's Guidance Manual.
Standard permitting practice is to use the entire critical low flow in the receiving waters to
determine dilution, utilizing a simple mass balance approach. Complete and instantaneous mixing
of the effluent with the receivingwaters is generallyassumed. Dilution is calculated as
D = (Q.+ Qu)/QW
Where:
Qu, is the maximum permitted wasteflow and
Q„ is the critical upstream streamflow, generally the summer 7Q10 flow.
Permit limits for individual toxicants are established for pollutants that have the reasonable
potential to cause or contribute to an excursion above a State water quality standard. Permit limits
are calculated using a mass balance approach as shown below.
Ca = ((Qu + Qw)(Cs)—(Qu)(Cu))/Qw
Where:
Ca is the allowable effluent concentration in units of mg/L or µg/L,
Cs is the North Carolina water quality standard,
Cu is the background concentration,
QW is the maximum permitted wasteflow and
Qu is the critical upstream streamflow, generally the summer 7Q10 flow.
Permits for all major facilities and any facility discharging complex wastewater will contain
whole effluent toxicity(WET) limits. The objective of these WET limits is to prevent discharge of
toxic substances in amounts likely to cause chronic or acute toxicity to wildlife in the receiving
stream. WET testing represents the only feasible method of evaluating the combined effects of
constituents of complex wastestreams.
To establish a WET limit, a facility's instream waste concentration(IWC) is first calculated
as follows.

IWC(%) _[Qwi(Qw+ Q,4)1(100)
The type of WET test required is based upon the facility's IWC, as well as upon discharge
and receiving water characteristics. For example, if the facility's 1WC is greater than or equal to
0.25 percent, the facility will generally perform the"North Carolina Ceriodaphnia Chronic Effluent
Bioassay Procedure". The limit is stated as "there may be no observable inhibition of reproduction
or significant mortality" at the effluent concentration equivalent to the facility's IWC. The
maximum permit limit is 90%.
If the facility's IWC is less than 0.25 percent, a 24 hour fathead minnow acute"No
Significant Mortality"limit will be applied. The procedure employed is the"Pass/Fail
Methodology For Determining Acute Toxicity In A Single Effluent Concentration".
Other limits are applicable to specific situations, such as episodic discharges or tidally
influenced waters, and alternative tests may be substituted by permittees under certain
circumstances. Detailed information on WET requirements is available from the Division.
General Procedure for Evaluating Mixing Zones
For the majority of discharges, permit limits are established using the approach outlined
above and no explicit mixing zone is established. As provided in 15A NCAC 2B.0204 (see
Appendix for the text of this rule), mixing zones for wastewater discharges can be established on a
case by case basis. This rule states that mixing zones can be established in order to provide
reasonable opportunity for the mixture of wastewater with the receiving waters, and specifies that
these zones be established such that discharges will not:
(1) result in acute toxicity to aquatic life or prevent free passage of aquatic organisms;
(2)result in offensive conditions;
(3)produce undesirable aquatic life or result in a dominance of nuisance species;
(4) endanger the public health or welfare.
The Division evaluates the feasibility and appropriateness of mixing zones when at least one
of the following conditions applies: 1)the permittee proposes to construct a diffuser; 2)the
Division believes that the discharge is causing or is likely to cause water quality problems if
standard practices are followed; 3)the Division receives a request for a mixing zone evaluation.
To date mixing zones have been established in only a few cases. Dilution levels at the
perimeter of these zones have been used to set WET limits and permit limits for individual
toxicants. Water quality standards do not apply within mixing zones, but must be met at the
perimeter of chronic mixing zones. Mixing zones have not been explicitly established for BOD,
fecal coliform or other pollutants.
The Division has no formal specifications for determining the size of chronic mixing zones,
and EPA's Technical Support Document for Water Quality-based Toxics Control(EPA/505/2-90-
001)provides no specific guidance on this issue. North Carolina rules provide that mixing zone
dimensions be determined on a case by case basis "after consideration of the magnitude and
character of the waste discharge and the size and character of the receiving waters". In practice, we
have implemented this provision by taking the following factors into account: type of receiving
waters (e.g. stream vs. estuary); outfall configuration; effluent characteristics; extent of
mixing/dilution; specific aquatic resource concerns (e.g. sensitive areas or species, recreational use,
navigation). State and federal resource agencies are consulted as appropriate.
2

To date the Division has established only chronic mixing zones. While no acute mixing
zones have thus far been established, the Division uses the procedures described in the Technical
Support Document for Water Quality-based Toxics Control to evaluate the dimensions of potential
acute mixing zones. That document(p. 71-72) outlines four alternatives for sizing acute mixing
zones to prevent lethality to passing organisms. The factors listed in the preceding paragraph are
also considered.
Analytical Approach
The Division requires that the degree of mixing of the effluent with receiving waters be
evaluated using either a dye study or a modeling analysis. In practice, modeling using the Cornell
Mixing Zone Expert System(CORMIX)has been the method of choice. CORMIX is an analytical
tool originally developed at Cornell University and now distributed by EPA's Center for Exposure
Assessment Modeling. CORMIX was intended for the analysis, prediction and design of aqueous
toxic or conventional pollutant discharges into diverse waterbodies. Its major emphasis is on the
prediction of plume geometry and dilution characteristics within a receiving water's initial mixing
zone. Plume behavior at larger distances can also be predicted. CORMIX can be used with single
pipe discharges as well as with multiport diffusers.
CORMIX requires data on the discharge configuration, discharge site morphometry,
ambient conditions and pollutant characteristics. Among the most important factors influencing the
extent of dilution are ambient depth, ambient velocity and effluent discharge velocity. Additional
information on the application of and input requirements for CORMIX may be found in User's
Manual for CORMIX:A Hydrodynamic Mixing Zone Model and Decision Support System for
Pollutant Discharges into Surface Waters,by Gerhard Jirka et al (USEPA Office of Science and
Technology, September 1996).
Models are run using conservative estimates of critical conditions. Critical conditions for
streams are typically defined by the velocity and cross-sectional area associated with the 7Q10 flow.
Critical conditions for lakes and estuaries are established on a case by case basis and generally
consider water levels, wind, lunar tides and other factors. Mixing zone analyses are generally
conducted using the permitted wasteflow, although other wasteflows may also be evaluated if there
is reason to believe that lower rates of mixing will occur under these conditions. In order to insure
that adequate data are available to support the modeling effort, the Division requires that site-
specific flow and velocity estimates be developed and that model inputs be based upon a cross-
section of the receiving waterbody at the discharge site or comparable data on site morphometry.
Case Descriptions
In order to illustrate how the Division has evaluated mixing zones, two recent examples are
briefly described below.
USMC-Camp Lejeune. Camp Lejeune, operated by the US Marine Corps (USMC), was
designing a new centralized wastewater treatment plant to replace several older facilities. This
plant, with a permitted capacity of 15 MGD, was to discharge into the estuary of the New River.
The potential impact of altered salinity on estuarine biota was a major concern.
In consultation with the North Carolina Division of Marine Fisheries, the Division
determined that aquatic resources would be adequately protected if at least 20:1 dilution was
3

attained within 50 meters of the outfall. The USMC engaged a consultant to conduct the necessary
field work and to assess mixing characteristics of the proposed outfall using CORMIX.
Several alternative diffuser designs were evaluated. A design was selected which exceeded
the dilution criteria described above and met the peak hydraulic requirements of the discharge. The
USMC is required to conduct ambient monitoring to evaluate the extent of mixing achieved by the
discharge.
City of Salisbury. The city of Salisbury was designing a new outfall on the Yadkin River to
replace two discharges into small streams. While the Yadkin is a sizeable waterbody, the discharge
would be located in the backwaters of a large impoundment. The Division was concerned that
ambient mixing would be relatively slow in this situation and that standard procedures may not
protect water quality.
An engineering firm hired by the city measured river cross-sections in the vicinity of the
discharge. The firm--in conjunction with the Division--used CORMIX to evaluate the mixing
characteristics of both a single pipe outfall and a multiport diffuser. After reviewing discharge and
receiving water characteristics, the Division determined that the mixing zone should not exceed one
third of the river width.
Using this criteria, mixing zones were developed for both the diffuser and single pipe
options. Since both mixing zones provided equivalent water quality protection, requiring water
quality standards to be met when the width of the plume reached one third of the river width, the
Division allowed the city to choose between the two options. Salisbury elected to construct a
diffuser because of the greater dilution obtained.
Further Development of Mixing Zone Policy
As noted above, the Division has established mixing zones in only a few instances. Under
these circumstances working on a case by case basis has proven to be an effective approach. The
number of mixing zone evaluations is likely to increase in the future,however. As this occurs it
will become important for us to ensure that mixing zones are evaluated in a consistent and
scientifically defensible fashion, and that our policy approach and technical requirements are clear
to the public.
The Division therefore intends to review its approach to mixing zone evaluation. This
review will focus on several key issues: 1) clarifying the conditions which should trigger a mixing
zone evaluation and the conditions under which complete and instantaneous mixing should be
assumed; 2) developing criteria for establishing the size of mixing zones; 3) developing guidelines
for the data collection, technical analysis and modeling necessary to support mixing zone
evaluations.
4

APPENDIX
NORTH CAROLINA'S MIXING ZONE RULE (15A NCAC 2B.0204)
.0204 LOCATION OF SAMPLING SITES AND MIXING ZONES
(a) Location of Sampling Sites. In conducting tests or making analytical determinations of classified
waters to determine conformity or nonconformity with the established standards, samples shall be
collected outside the limits of prescribed mixing zones. However, where appropriate, samples shall
be collected within the mixing zone in order to ensure compliance with in-zone water quality
requirements as outlined in Paragraph (b) of this Rule.
(b) Mixing Zones. A mixing zone may be established in the area of a discharge in order to provide
reasonable opportunity for the mixture of the wastewater with the receiving waters. Water quality
standards will not apply within regions defined as mixing zones, except that such zones will be
subject to the conditions established in accordance with this Rule. The limits of such mixing zones
will be defmed by the division on a case-by-case basis after consideration of the magnitude and
character of the waste discharge and the size and character of the receiving waters. Mixing zones
will be determined such that discharges will not:
(1)result in acute toxicity to aquatic life [as defmed by Rule .0202(1)of this Section] or
prevent free passage of aquatic organisms around the mixing zone;
(2) result in offensive conditions;
(3)produce undesirable aquatic life or result in a dominance of nuisance species outside of the
assigned mixing zone;
(4)endanger the public health or welfare.
In addition, a mixing zone will not be assigned for point source discharges of fecal coliform
organisms in waters classified "WS-II," "WS-III," "B," "SB," or "SA." For the discharge of heated
wastewater, compliance with federal rules and regulations pursuant to Section 316(a)of the Federal
Water Pollution Control Act, as amended, shall constitute compliance with Subparagraph (b) of this
Rule.
History Note: Authority G.S. 143-214.1;
Eff. February 1, 1976;
Amended Eff. October 1, 1989; February 1, 1986; September 9, 1979.
5

APPENDIX VIII
CORMIX OUTPUT FILES FOR THE OPTIMIZED SINGLE PORT
AND MULTI-PORT SIMULATIONS

VERTS_RISE_CONSTRICT_20180516.ses
CORMIX SESSION REPORT:
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
CORMIX MIXING ZONE EXPERT SYSTEM
CORMIX Version 10.OGT
HYDRO1:version-10.0.0.0 July,2016
SITE NAME/LABEL: EMERALD ISLE BOAT RAMP
DESIGN CASE: VERT 5 RISE (10 in RISE) 8 INCH PIPE
FILE NAME: Z:\GMA\243XX-Bogue Banks\24312 CORMIX
Study\CORMIX Runs\CORMIX Model Files\VERT5 RISE CONSTRICT 20180516.prd
using subsystem CORMIX1: single Port Discharges
Start of session: 06/19/2018--10:32:16
..****************************************************----.,.****************
SUMMARY OF INPUT DATA:
AMBIENT PARAMETERS:
Cross-section = bounded
width BS = 253 m
Channel regularity ICHREG = 1
Ambient flowrate QA = 53.27 mA3/s
Average depth HA = 1.23 m
Depth at discharge HD = 1.31 m
Darcy-Weisbach friction factor F = 0.0458
Calculated from Manning's n = 0.025
wind velocity UW = 2.63 m/s
TIDAL SIMULATION at time Tsim = 1 hours
Instantaneous ambient velocity UA = 0.1718 m/s
Maximum tidal velocity UaMAX = 0.324 m/s
Rate of tidal reversal duA/dt = 0.1718 (m/s)/hour
Period of reversal T = 12.31 hours
Stratification Type STRCND = U
Surface density RHOAS = 1016.67 kg/mA3
Bottom density RHOAB = 1016.67 kg/mA3
DISCHARGE PARAMETERS: Single Port Discharge
Nearest bank = right
Distance to bank DISTB = 105 m
Port diameter DO = 0.2032 m
Port cross-sectional area AO = 0.0324 mA2
Discharge velocity u0 = 1.62 m/s
Discharge flowrate QO = 0.052554 mA3/s
Discharge port height HO = 0.25 m
vertical discharge angle THETA = 5 deg
Horizontal discharge angle SIGMA = 90 deg
Discharge density RHO() = 1006.61 kg/mA3
Density difference DRHO = 10.0600 kg/mA3
Buoyant acceleration GPO = 0.097 m/sA2
Discharge concentration CO = 5 m g/1
Surface heat exchange coeff. KS = 0 m/s
Coefficient of decay KD = 0 /s
DISCHARGE/ENVIRONMENT LENGTH SCALES:
LQ = 0.18 m Lm = 1.70 m Lb = 1.00 m
LM = 2.21 m Lm' = 99999 m Lb' = 99999 m
UNSTEADY TIDAL SCALES:
Tu = 0.1400 hours Lu = 12.13 m Lmin= 0.56 m
NON-DIMENSIONAL PARAMETERS:
Port densimetric Froude number FRO = 11. 54
velocity ratio R = 9.43
MIXING ZONE / TOXIC DILUTION ZONE / AREA OF INTEREST PARAMETERS:
Toxic discharge = no
water quality standard specified = yes
water quality standard CSTD = 2 mg/1
Regulatory mixing zone = yes
Regulatory mixing zone specification = distance
Page 1

VERT5_RISE_CONSTRICT_20180516.ses
Regulatory mixing zone value = 10 m (mA2 if area)
Region of interest = 2530 m
****************•****************•*****************•****************************
HYDRODYNAMIC CLASSIFICATION:
1 FLOW CLASS = H4-90 1
This flow configuration applies to a layer corresponding to the full water
depth at the discharge site.
Applicable layer depth = water depth = 1.31 m
Limiting Dilution S = (QA/Q0)+ 1.0 = 1014.7
MIXING ZONE EVALUATION (hydrodynamic and regulatory summary) :
X-Y-Z Coordinate system:
origin is located at the BOTTOM below the port/diffuser center:
105 m from the right bank/shore.
Number of display steps NSTEP = 100 per module.
NEAR-FIELD REGION (NFR) CONDITIONS :
Note: The NFR is the zone of strong initial mixing. It has no regulatory
implication. However, this information may be useful for the discharge
designer because the mixing in the NFR is usually sensitive to the
discharge design conditions.
Pollutant concentration at NFR edge c = 0.9168 mg/1
Dilution at edge of NFR s = 5.5
NFR Location: x = 1.78 m
(centerline coordinates) y = 3.46 m
z = 1.31 m
NFR plume dimensions: half-width (bh) = 0.62 m
thickness (bv) = 0.62 m
Cumulative travel time: 5.8559 sec.
Buoyancy assessment:
The effluent density is less than the surrounding ambient water
density at the discharge level .
Therefore, the effluent is POSITIVELY BUOYANT and will tend to rise towards
the surface.
PLUME BANK CONTACT SUMMARY:
Plume in bounded section does not contact bank.
UNSTEADY TIDAL ASSESSMENT:
Because of the unsteadiness of the ambient current during the tidal
reversal , CORMIX predictions have been TERMINATED at:
x = 98.46 m
y = 3.46 m
z = 1.31 m.
For this condition AFTER TIDAL REVERSAL, mixed water from the previous
half-cycle becomes re-entrained into the near field of the discharge,
increasing pollutant concentrations compared to steady-state predictions.
A pool of mixed water formed at slack tide will be advected downstream
in this phase.
************************ TOXIC DILUTION ZONE SUMMARY ************************
No TDZ was specified for this simulation.
********************** REGULATORY MIXING ZONE SUMMARY ***********************
The plume conditions at the boundary of the specified RMZ are as follows:
Pollutant concentration c = 0.66171 mg/1
Corresponding dilution s = 7.6
Plume location: x = 10 m
(centerline coordinates) y = 3.46 m
z = 1.31 m
Plume dimensions: half-width (bh) = 3.67 m
Page 2

VERTS_RISE_CONSTRICT_20180516.prd
CORMIX1 PREDICTION FILE:
111111111111111111111111111111111111111111111111111111111111111111111111111111
11111111111111111
CORMIX MIXING ZONE EXPERT SYSTEM
Subsystem CORMIX1: Single Port Discharges
CORMIX Version 10.0GT
HYDRO1 version 10.0.0.0 July 2016
CASE DESCRIPTION
Site name/label : EMERALD ISLE BOAT RAMP
Design case: VERT 5 RISE (10 in RISE) 8 INCH PIPE
FILE NAME: Z:\. . .MIX Model Files\VERT5_RISE_CONSTRICT_20180516.prd
Time stamp: 06/19/2018--10:32:16
ENVIRONMENT PARAMETERS (metric units)
Bounded section
BS = 253.00 AS = 310.00 QA = 53.27 ICHREG= 1
HA = 1.23 HD = 1.31
Tidal Simulation at TIME = 1.000 h
PERIOD= 12.31 h UAmax = 0.324 dUa/dt= 0.172 (m/s)/h
UA = 0.172 F = 0.046 USTAR =0.1301E-01
uw = 2.629 UWSTAR=0.2933E-02
Uniform density environment
STRCND= U RHOAM = 1016.6700
DISCHARGE PARAMETERS (metric units)
BANK = RIGHT DISTB = 105.00
DO = 0.203 AO = 0.032 HO = 0.25 SUBO = 1.06
THETA = 5.00 SIGMA = 90.00
UO = 1.621 QO = 0.053 =0. 5255E-01
RHOO = 1006.6100 DRHOO =0.1006E+02 GPO =0.9704E-01
CO =0. 5000E+01 CUNITS= mg/1
IPOLL = 1 KS =0.0000E+00 KD =0.0000E+00
FLUX VARIABLES (metric units)
QO =0.5255E-01 MO =0.8517E-01 JO =0. 5100E-02 SIGNJO= 1.0
Associated length scales (meters)
LQ = 0.18 LM = 2.21 Lm = 1.70 Lb = 1.00
Lmp = 99999.00 Lbp = 99999.00
Tidal : Tu = 0.1400 h Lu = 12.128 Lmin = 0. 556
NON-DIMENSIONAL PARAMETERS
FRO = 11. 54 R = 9.43
FLOW CLASSIFICATION
111111111111111111111111111111111111111111
1 Flow class (CORMIX1) = H4-90 1
1 Applicable layer depth HS = 1.31 1
1 Limiting Dilution S =QA/QO= 1014.69 1
111111111111111111111111111111111111111111
MIXING ZONE / TOXIC DILUTION / REGION OF INTEREST PARAMETERS
CO =0. 5000E+01 CUNITS= mg/1
NTOX = 0
NSTD = 1 CSTD =0.2000E+01
REGMZ = 1
REGSPC= 1 XREG = 10.00 WREG = 0.00 AREG = 0.00
XINT = 2530.00 XMAX = 2530.00
X-Y-Z COORDINATE SYSTEM:
ORIGIN is located at the bottom and below the center of the port:
105.00 m from the RIGHT bank/shore.
x-axis points downstream, Y-axis points to left, Z-axis points upward.
Page 1

VERT5_RISE_CONSTRICT_20180516.prd
NSTEP = 100 display intervals per module
BEGIN MOD101: DISCHARGE MODULE
X Y Z S C B Uc TT
0.00 0.00 0.25 1.0 0. 500E+01 0.10 1.621 .00000E+00
END OF MOD101: DISCHARGE MODULE
BEGIN CORJET (MOD110) : JET/PLUME NEAR-FIELD MIXING REGION
Jet/plume transition motion in weak crossflow.
Zone of flow establishment: THETAE= 5.00 SIGMAS= 87.48
LE = 0.66 XE = 0.01 YE = 0.66 ZE = 0.31
Profile definitions:
B = Gaussian 1/e (37%) half-width, normal to trajectory
S = hydrodynamic centerline dilution
C = centerline concentration (includes reaction effects, if any)
Uc = Local centerline excess velocity (above ambient)
TT = Cumulative travel time
X Y Z S C B Uc TT
0.00 0.00 0.25 1.0 0. 500E+01 0.10 1.621 .00000E+00
0.01 0.66 0.31 1.0 0. 500E+01 0.10 1.621 . 56392E-02
0.02 0.69 0.31 1.0 0. 500E+01 0.11 1.621 .17156E-01
0.02 0.71 0.32 1.0 0. 500E+01 0.11 1.621 .28993E-01
0.02 0.74 0.32 1.0 0. 500E+01 0.11 1.621 .41151E-01
0.02 0.76 0.32 1.0 0. 500E+01 0.11 1.621 .53631E-01
0.02 0.79 0.32 1.0 0. 500E+01 0.12 1.621 .66437E-01
0.02 0.81 0.33 1.0 0. 500E+01 0.12 1.621 .79569E-01
0.03 0.84 0.33 1.0 0.493E+01 0.12 1.621 .93031E-01
0.03 0.86 0.33 1.0 0.481E+01 0.13 1.621 .10682E+00
0.03 0.89 0.33 1.1 0.470E+01 0.13 1.621 .12095E+00
0.03 0.91 0.34 1.1 0.459E+01 0.13 1.621 .13541E+00
0.04 0.94 0.34 1.1 0.448E+01 0.14 1.621 .15021E+00
0.04 0.96 0.34 1.1 0.438E+01 0.14 1.621 .16534E+00
0.04 0.99 0.34 1.2 0.429E+01 0.14 1.610 .18082E+00
0.05 1.01 0.35 1.2 0.419E+01 0.14 1. 573 .19665E+00
0.05 1.04 0.35 1.2 0.410E+01 0.15 1.538 .21282E+00
0.05 1.06 0.35 1.2 0.401E+01 0.15 1.504 .22934E+00
0.06 1.09 0.36 1.3 0. 393E+01 0.15 1.471 .24622E+00
0.06 1.10 0.36 1.3 0. 389E+01 0.16 1.454 .25479E+00
0.06 1.13 0.36 1.3 0.381E+01 0.16 1.423 .27220E+00
0.07 1.15 0.36 1.3 0.373E+01 0.16 1.392 .28997E+00
0.07 1.18 0.37 1.4 0.365E+01 0.16 1.363 .30811E+00
0.08 1.20 0.37 1.4 0.358E+01 0.17 1.334 .32661E+00
0.08 1.23 0.37 1.4 0.351E+01 0.17 1.306 .34549E+00
0.09 1.25 0.38 1. 5 0.344E+01 0.17 1.279 .36473E+00
0.09 1.27 0.38 1. 5 0.337E+01 0.18 1.252 .38436E+00
0.10 1.30 0.38 1. 5 0.331E+01 0.18 1.226 .40436E+00
0.10 1.32 0.39 1. 5 0.324E+01 0.18 1.201 .42475E+00
0.11 1.35 0.39 1.6 0.318E+01 0.19 1.177 .44553E+00
0.11 1.37 0.39 1.6 0.312E+01 0.19 1.153 .46670E+00
0.12 1.40 0.40 1.6 0.306E+01 0.19 1.130 .48827E+00
0.13 1.42 0.40 1.7 0.300E+01 0.20 1.108 . 51023E+00
0.13 1.45 0.41 1.7 0.295E+01 0.20 1.085 .53260E+00
0.14 1.47 0.41 1.7 0.289E+01 0.20 1.064 .55538E+00
0.14 1.49 0.41 1.8 0.284E+01 0.21 1.043 . 57857E+00
Page 2

VERTS_RISE_CONSTRICT_20180516.prd 1
0.15 1. 52 0.42 1.8 0.279E+01 0.21 1.022 .60217E+00
0.16 1. 54 0.42 1.8 0.274E+01 0.22 1.002 .62620E+00
0.17 1. 57 0.43 1.9 0.269E+01 0.22 0.983 .65065E+00
0.17 1. 59 0.43 1.9 0.264E+01 0.22 0.964 .67552E+00
0.18 1.61 0.44 1.9 0.259E+01 0.23 0.945 .70084E+00
0.19 1.64 0.44 2.0 0.254E+01 0.23 0.927 .72659E+00
0.20 1.66 0.44 2.0 0.250E+01 0.23 0.909 .75278E+00
0.21 1.68 0.45 2.0 0.245E+01 0.24 0.891 .77942E+00
0.22 1.71 0.45 2.1 0.241E+01 0.24 0.874 .80651E+00
0.22 1.73 0.46 2.1 0.237E+01 0.24 0.857 .83406E+00
0.23 1.75 0.46 2.1 0.233E+01 0.25 0.841 .86207E+00
0.24 1.78 0.47 2.2 0.229E+01 0.25 0.825 .89054E+00
0.25 1.80 0.47 2.2 0.225E+01 0.26 0.809 .91949E+00
0.26 1.82 0.48 2.3 0.221E+01 0.26 0.793 .94890E+00
0.27 1.85 0.48 2.3 0.217E+01 0.26 0.778 .97880E+00
0.28 1.87 0.49 2.3 0.213E+01 0.27 0.763 .10092E+01
0.29 1.89 0.49 2.4 0.209E+01 0.27 0.749 .10401E+01
0.30 1.91 0.50 2.4 0.206E+01 0.28 0.735 .10714E+01
0.31 1.94 0.50 2.5 0.202E+01 0.28 0.721 .11033E+01
**WATER QUALITY STANDARD OR CCC HAS BEEN FOUND**
The pollutant concentration in the plume falls below water quality standard
or CCC value of 0.200E+01 in the current prediction interval .
This is the spatial extent of concentrations exceeding the water quality
standard or CCC value.
0.32 1.96 0. 51 2. 5 0.199E+01 0.28 0.707 .11356E+01
0.33 1.98 0. 51 2.6 0.195E+01 0.29 0.694 .11685E+01
0.35 2.00 0.52 2.6 0.192E+01 0.29 0.680 .12019E+01
0.36 2.03 0.53 2.6 0.189E+01 0.30 0.668 .12358E+01
0.37 2.05 0.53 2.7 0.186E+01 0.30 0.655 .12702E+01
0.38 2.07 0.54 2.7 0.182E+01 0.31 0.643 .13051E+01
0.39 2.09 0. 54 2.8 0.179E+01 0.31 0.631 .13406E+01
0.41 2.11 0. 55 2.8 0.176E+01 0.31 0.619 .13766E+01
0.42 2.13 0. 55 2.9 0.173E+01 0.32 0.607 .14131E+01
0.43 2.15 0. 56 2.9 0.170E+01 0.32 0. 596 .14501E+01
0.44 2.18 0. 57 3.0 0.168E+01 0.33 0. 585 .14877E+01
0.46 2.20 0.57 3.0 0.165E+01 0.33 0. 574 .15259E+01
0.47 2.22 0.58 3.1 0.162E+01 0.34 0. 563 .15646E+01
0.48 2.24 0. 59 3.1 0.159E+01 0.34 0.553 .16038E+01
0.50 2.26 0. 59 3.2 0.157E+01 0.34 0. 543 .16436E+01
0.51 2.28 0.60 3.2 0.154E+01 0.35 0.533 .16839E+01
0. 52 2.30 0.60 3.3 0.152E+01 0.35 0. 523 .17248E+01
0. 54 2.32 0.61 3.3 0.149E+01 0.36 0. 513 .17663E+01
0. 55 2.34 0.62 3.4 0.147E+01 0.36 0.504 .18083E+01
0.57 2.36 0.62 3. 5 0.145E+01 0.37 0.495 .18509E+01
0.59 2.39 0.63 3. 5 0.141E+01 0.37 0.481 .19159E+01
0.61 2.41 0.64 3.6 0.139E+01 0.38 0.473 .19599E+01
0.62 2.43 0.65 3.7 0.137E+01 0.38 0.464 .20044E+01
0.64 2.45 0.65 3.7 0.135E+01 0.39 0.456 .20496E+01
0.65 2.46 0.66 3.8 0.132E+01 0.39 0.448 .20953E+01
0.67 2.48 0.67 3.8 0.130E+01 0.40 0.440 .21415E+01
0.68 2. 50 0.67 3.9 0.128E+01 0.40 0.433 .21884E+01
0.70 2. 52 0.68 4.0 0.126E+01 0.41 0.425 .22358E+01
0.71 2. 54 0.69 4.0 0.125E+01 0.41 0.418 .22837E+01
0.73 2. 56 0.70 4.1 0.123E+01 0.41 0.411 .23322E+01
0.75 2.57 0.70 4.1 0.121E+01 0.42 0.404 .23813E+01
0.76 2. 59 0.71 4.2 0.119E+01 0.42 0.397 .24309E+01
0.78 2.61 0.72 4.3 0.117E+01 0.43 0.391 .24811E+01
0.80 2.63 0.73 4.3 0.116E+01 0.43 0.384 .25318E+01
0.81 2.64 0.73 4.4 0.114E+01 0.44 0.378 .25831E+01
0.83 2.66 0.74 4. 5 0.112E+01 0.44 0.372 .26349E+01
0.85 2.68 0.75 4. 5 0.111E+01 0.45 0.366 .26872E+01
0.87 2.70 0.75 4.6 0.109E+01 0.45 0.360 .27401E+01
0.88 2.71 0.76 4.6 0.108E+01 0.45 0.355 .27935E+01
0.90 2.73 0.77 4.7 0.106E+01 0.46 0.349 .28474E+01
0.92 2.75 0.78 4.8 0.105E+01 0.46 0.344 .29019E+01
0.94 2.76 0.79 4.8 0.103E+01 0.47 0.339 .29568E+01
Page 3

VERTS_RISE_CONSTRICT_20180516.prd
0.96 2.78 0.79 4.9 0.102E+01 0.47 0.334 .30123E+01
0.97 2.79 0.80 5.0 0.101E+01 0.48 0.329 .30683E+01
0.99 2.81 0.81 5.0 0.993E+00 0.48 0.324 .31249E+01
1.01 2.83 0.82 5.1 0.980E+00 0.48 0.319 .31819E+01
1.03 2.84 0.82 5.1 0.973E+00 0.49 0.317 .32106E+01
cumulative travel time = 3.2106 sec ( 0.00 hrs)
END OF CORJET (MOD110) : JET/PLUME NEAR-FIELD MIXING REGION
BEGIN MOD131: LAYER BOUNDARY/TERMINAL LAYER APPROACH
Control volume inflow:
X Y Z S C B TT
1.03 2.84 0.82 5.1 0.988E+00 0.49 .32106E+01
Profile definitions:
BV = Gaussian 1/e (37%) vertical thickness
BH = Gaussian 1/e (37%) horizontal half-width, normal to trajectory
ZU = upper plume boundary (z-coordinate)
ZL = lower plume boundary (z-coordinate)
S = hydrodynamic centerline dilution
C = centerline concentration (includes reaction effects, if any)
TT = Cumulative travel time
X Y Z S C BV BH ZU ZL
TT
0.66 2.53 1.31 5.1 0.972E+00 0.00 0.00 1.31 1.31
.32106E+01
0.77 2.62 1.31 5.1 0.973E+00 0.39 0.20 1.31 0.92
.32106E+01
0.88 2.72 1.31 5.1 0.973E+00 0.47 0.28 1.31 0.85
.32106E+01
0.99 2.81 1.31 5.1 0.974E+00 0. 51 0.34 1.31 0.80
.32106E+01
1.10 2.90 1.31 5.1 0.972E+00 0. 55 0.39 1.31 0.76
.34751E+01
1.22 3.00 1.31 5.2 0.961E+00 0. 57 0.44 1.31 0.74
.38719E+01
1.33 3.09 1.31 5.3 0.946E+00 0. 59 0.48 1.31 0.72
.42687E+01
1.44 3.18 1.31 5.4 0.932E+00 0.61 0. 52 1.31 0.70
.46655E+01
1.55 3.28 1.31 5.4 0.924E+00 0.62 0. 56 1.31 0.69
. 50623E+01
1.66 3.37 1.31 5.4 0.919E+00 0.62 0. 59 1.31 0.69
.54591E+01
1.78 3.46 1.31 5. 5 0.917E+00 0.62 0.62 1.31 0.69
.58559E+01
Cumulative travel time = 5.8559 sec ( 0.00 hrs)
END OF MOD131: LAYER BOUNDARY/TERMINAL LAYER APPROACH
BEGIN MOD155: WEAKLY DEFLECTED SURFACE/BOTTOM PLUME
SURFACE/BOTTOM PLUME into a co-flow (or counter-flow)
This flow region is INSIGNIFICANT in spatial extent and will be by-passed.
END OF MOD155: WEAKLY DEFLECTED SURFACE/BOTTOM PLUME
Page 4

VERT5_RISE_CONSTRICT_20180516.prd
BEGIN MOD156: STRONGLY DEFLECTED SURFACE/BOTTOM PLUME
SPECIAL CO-FLOWING, COUNTER-FLOWING OR VERTICAL DISCHARGE CASE:
THIS FLOW REGION DOES NOT OCCUR.
END OF MOD156: STRONGLY DEFLECTED SURFACE/BOTTOM PLUME
** End of NEAR-FIELD REGION (NFR) **
The initial plume WIDTH values in the next far-field module will be
CORRECTED by a factor 1.48 to conserve the mass flux in the far-field!
BEGIN MOD141: BUOYANT AMBIENT SPREADING
Profile definitions:
BV = top-hat thickness, measured vertically
BH = top-hat half-width, measured horizontally in Y-direction
ZU = upper plume boundary (Z-coordinate)
ZL = lower plume boundary (Z-coordinate)
S = hydrodynamic average (bulk) dilution
C = average (bulk) concentration (includes reaction effects, if any)
TT = Cumulative travel time
Plume Stage 1 (not bank attached) :
X Y Z S C BV BH ZU ZL
TT
1.78 3.46 1.31 5. 5 0.917E+00 0.92 0.92 1.31 0.39
.58559E+01
5.16 3.46 1.31 6.8 0.738E+00 0.47 2.27 1.31 0.84
.25548E+02
8.55 3.46 1.31 7.4 0.678E+00 0.36 3.29 1.31 0.95
.45240E+02
** REGULATORY MIXING ZONE BOUNDARY **
In this prediction interval the plume DOWNSTREAM distance meets or exceeds
the regulatory value = 10.00 m.
This is the extent of the REGULATORY MIXING ZONE.
11.94 3.46 1.31 7.8 0.643E+00 0.30 4.16 1.31 1.01
.64932E+02
15.33 3.46 1.31 8.1 0.617E+00 0.27 4.95 1.31 1.04
.84624E+02
18.71 3.46 1.31 8.4 0. 596E+00 0.25 5.68 1.31 1.07
.10432E+03
22.10 3.46 1.31 8.7 0. 576E+00 0.23 6.37 1.31 1.08
.12401E+03
25.49 3.46 1.31 9.0 0. 558E+00 0.22 7.02 1.31 1.09
.14370E+03
28.88 3.46 1.31 9.3 0. 540E+00 0.21 7.64 1.31 1.10
.16339E+03
32.26 3.46 1.31 9.6 0. 522E+00 0.20 8.23 1.31 1.11
.18308E+03
35.65 3.46 1.31 9.9 0. 504E+00 0.20 8.80 1.31 1.11
.20278E+03
39.04 3.46 1.31 10.3 0.486E+00 0.20 9.36 1.31 1.11
.22247E+03
42.43 3.46 1.31 10.7 0.468E+00 0.19 9.90 1.31 1.12
.24216E+03
45.81 3.46 1.31 11.1 0.451E+00 0.19 10.42 1.31 1.12
.26185E+03
49.20 3.46 1.31 11. 5 0.433E+00 0.19 10.93 1.31 1.12
.28154E+03
52. 59 3.46 1.31 12.0 0.415E+00 0.20 11.43 1.31 1.12
Page 5

VERT5_RISE_CONSTRICT_20180516.prd
.30124E+03
55.98 3.46 1.31 12.6 0. 398E+00 0.20 11.91 1.31 1.11
.32093E+03
59.36 3.46 1.31 13.1 0. 382E+00 0.20 12.39 1.31 1.11
.34062E+03
62.75 3.46 1.31 13.7 0.365E+00 0.20 12.86 1.31 1.11
.36031E+03
66.14 3.46 1.31 14.3 0.349E+00 0.21 13.32 1.31 1.10
.38000E+03
69. 52 3.46 1.31 15.0 0.334E+00 0.21 13.77 1.31 1.10
.39970E+03
72.91 3.46 1.31 15.7 0.319E+00 0.21 14.21 1.31 1.10
.41939E+03
76.30 3.46 1.31 16.4 0.305E+00 0.22 14.65 1.31 1.09
.43908E+03
79.69 3.46 1.31 17.2 0.291E+00 0.22 15.08 1.31 1.09
.45877E+03
83.07 3.46 1.31 18.0 0.278E+00 0.23 15.50 1.31 1.08
.47846E+03
86.46 3.46 1.31 18.8 0.265E+00 0.24 15.92 1.31 1.07
.49816E+03
89.85 3.46 1.31 19.7 0.254E+00 0.24 16.33 1.31 1.07
. 51785E+03
93.24 3.46 1.31 20.6 0.242E+00 0.25 16.74 1.31 1.06
.53754E+03
96.62 3.46 1.31 21.6 0.231E+00 0.26 17.14 1.31 1.05
.55723E+03
98.46 3.46 1.31 22.2 0.226E+00 0.26 17.36 1.31 1.05
.56792E+03
Cumulative travel time = 567.9185 sec ( 0.16 hrs)
CORMIX prediction has been TERMINATED at last prediction interval .
Limiting time due to TIDAL REVERSAL has been reached.
END OF MOD141: BUOYANT AMBIENT SPREADING
CORMIxl: single Port Discharges End of Prediction File
111111111111111111111111111111111111111111111111111111111111111111111111111111
11111111111111111
Page 6

MULTI_6_20180524.ses
CORMIX SESSION REPORT:
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
CORMIX MIXING ZONE EXPERT SYSTEM
CORMIX Version 10.0GT
HYDR02:version-10.0.0.0 July,2016
SITE NAME/LABEL: EMERALD ISLE BOAT RAMP
DESIGN CASE: MULTI 6
FILE NAME: Z:\GMA\243XX-Bogue Banks\24312 CORMIX
Study\CORMIX Runs\CORMIX Model Files\MULTI 6 20180524.prd
Using subsystem CORMIX2: Multiport Diffuser Discharges
Start of session: 06/19/2018--13:48:05
*****************************************************************************
1 SUMMARY OF INPUT DATA:
AMBIENT PARAMETERS:
Cross-section = bounded
width BS = 253 m
Channel regularity ICHREG = 1
Ambient flowrate QA = 53.27 mA3/s
Average depth HA = 1.23 m
Depth at discharge HD = 1.31 m
Darcy-Weisbach friction factor F = 0.0458
Calculated from Manning's n = 0.025
Wind velocity UW = 2.63 m/s
TIDAL SIMULATION at time Tsim = 1 hours
Instantaneous ambient velocity UA = 0.1718 m/s
Maximum tidal velocity UaMAX = 0.324 m/s
Rate of tidal reversal dUA/dt = 0.1718 (m/s)/hour
Period of reversal T = 12.31 hours
Stratification Type STRCND = U
Surface density RHOAS = 1016.67 kg/mA3
Bottom density RHOAB = 1016.67 kg/mA3
DISCHARGE PARAMETERS: Submerged Multiport Diffuser Discharge
Diffuser type DITYPE = staged perpendicular
Diffuser length LD = 6.10 m
Nearest bank = right
Diffuser endpoints YB1 = 105 m; YB2 = 111.10 m
Number of openings NOPEN = 3
Number of Risers NRISER = 3
Ports/Nozzles per Riser NPPERR = 1
Spacing between risers/openings SPAS = 3.05 m
Port/Nozzle diameter DO = 0.0762 m
with contraction ratio = 1
Equivalent slot width BO = 0.0022 m
Total area of openings TAO = 0.0137 mA2
Discharge velocity u0 = 3.84 m/s
Total discharge flowrate QO = 0.052554 mA3/s
Discharge port height HO = 0.25 m
Nozzle arrangement BETYPE = staged
Diffuser alignment angle GAMMA = 90 deg
vertical discharge angle THETA = 5 deg
Actual vertical discharge angle THEAC = 5 deg
Horizontal discharge angle SIGMA = 90 deg
Relative orientation angle BETA = 0 deg
Discharge density RHO() = 1006.61 kg/mA3
Density difference DRHO = 10.0600 kg/mA3
Buoyant acceleration GPO = 0.097 m/sA2
Discharge concentration CO = 5 mg/1
Surface heat exchange coeff. KS = 0 m/s
Coefficient of decay KD = 0 /s
FLUX VARIABLES PER UNIT DIFFUSER LENGTH:
Discharge (volume flux) q0 = 0.008621 mA2/s
Momentum flux m0 = 0.033117 mA3/sA2
Buoyancy flux j0 = 0.000837 mA3/sA3
Page 1

MULTI_6_20180524.ses
DISCHARGE/ENVIRONMENT LENGTH SCALES:
LQ = 0.00 m Lm = 1.12 m LM = 3.73 m
lm' = 99999 m Lb' = 99999 m La = 99999 m
UNSTEADY TIDAL SCALES:
Tu = 0.1617 hours Lu = 16.17 m Lmin= 1.39 m
(These refer to the actual discharge/environment length scales.)
NON-DIMENSIONAL PARAMETERS:
Slot Froude number FRO = 260.30
Port/nozzle Froude number FRDO = 44.67
Velocity ratio R = 22.35
MIXING ZONE / TOXIC DILUTION ZONE / AREA OF INTEREST PARAMETERS:
Toxic discharge = no
Water quality standard specified = yes
Water quality standard CSTD = 2 mg/1
Regulatory mixing zone = yes
Regulatory mixing zone specification = distance
Regulatory mixing zone value = 10 m (mA2 if area)
Region of interest = 2530 m
HYDRODYNAMIC CLASSIFICATION:
1 FLOW CLASS = MU6
* *
This flow configuration applies to a layer corresponding to the full water
depth at the discharge site.
Applicable layer depth = water depth = 1.31 m
Limiting Dilution S = (QA/Q0)+ 1.0 = 1014.7
MIXING ZONE EVALUATION (hydrodynamic and regulatory summary) :
X-Y-Z Coordinate system:
Origin is located at the BOTTOM below the port/diffuser center:
108.05 m from the right bank/shore.
Number of display steps NSTEP = 100 per module.
NEAR-FIELD REGION (NFR) CONDITIONS :
Note: The NFR is the zone of strong initial mixing. It has no regulatory
implication. However, this information may be useful for the discharge
designer because the mixing in the NFR is usually sensitive to the
discharge design conditions.
Pollutant concentration at NFR edge c = 0.1707 mg/1
Dilution at edge of NFR s = 29.3
NFR Location: x = 6.55 m
(centerline coordinates) y = 2.61 m
z = 1.31 m
NFR plume dimensions: half-width (bh) = 3.59 m
thickness (bv) = 1.31 m
Cumulative travel time: 38.1335 sec.
Buoyancy assessment:
The effluent density is less than the surrounding ambient water
density at the discharge level .
Therefore, the effluent is POSITIVELY BUOYANT and will tend to rise towards
the surface.
Near-field instability behavior:
The diffuser flow will experience instabilities with full vertical mixing
in the near-field.
There may be benthic impact of high pollutant concentrations.
Page 2

MULTI_6_20180524.ses
FAR-FIELD MIXING SUMMARY:
Plume becomes vertically fully mixed WITHIN NEAR-FIELD at 0 m
downstream, but RE-STRATIFIES LATER and is not mixed in the far-field.
PLUME BANK CONTACT SUMMARY:
Plume in bounded section does not contact bank.
UNSTEADY TIDAL ASSESSMENT:
Because of the unsteadiness of the ambient current during the tidal
reversal , CORMIX predictions have been TERMINATED at:
x = 98.46 m
y = 2.61 m
z = 1.31 m.
For this condition AFTER TIDAL REVERSAL, mixed water from the previous
half-cycle becomes re-entrained into the near field of the discharge,
increasing pollutant concentrations compared to steady-state predictions.
A pool of mixed water formed at slack tide will be advected downstream
in this phase.
************************ TOXIC DILUTION ZONE SUMMARY ************------**----
No TDZ was specified for this simulation.
********************** REGULATORY MIXING ZONE SUMMARY ***********************
The plume conditions at the boundary of the specified RMZ are as follows:
Pollutant concentration c = 0.16483 mg/1
Corresponding dilution s = 30.3
Plume location: x = 10 m
(centerline coordinates) y = 2.61 m
z = 1.31 m
Plume dimensions: half-width (bh) = 4.45 m
thickness (bv) = 1.12 m
Cumulative travel time: 58.1709 sec.
Note:
Plume concentration c and dilution s values are reported based on prediction
file values - assuming linear interpolation between predicted points just
before and just after the RMZ boundary has been detected.
Please ensure a small step size is used in the prediction file to account
for this linear interpolation. step size can be controlled by increasing
(reduces the prediction step size) or decreasing (increases the prediction
step size) the - Output Steps per Module - in CORMIX input.
At this position, the plume is NOT IN CONTACT with any bank.
Furthermore, the specified water quality standard has indeed been met
within the RMZ. In particular:
The ambient water quality standard was encountered at the following
plume position:
water quality standard = 2 mg/1
Corresponding dilution s = 3.4
Plume location: x = 0.05 m
(centerline coordinates) y = 0.02 m
z = 0.26 m
Plume dimensions: half-width (bh) = 3.05 m
thickness (bv) = 0.01 m
**********"*********** FINAL DESIGN ADVICE AND COMMENTS **********************
CORMIX2 uses the TWO-DIMENSIONAL SLOT DIFFUSER CONCEPT to represent
the actual three-dimensional diffuser geometry. Thus, it approximates
the details of the merging process of the individual jets from each
port/nozzle.
In the present design, the spacing between adjacent ports/nozzles
(or riser assemblies) is of the order of, or less than, the local
water depth so that the slot diffuser approximation holds well .
Nevertheless, if this is a final design, the user is advised to use a
final CORMIX1 (single port discharge) analysis, with discharge data
for an individual diffuser jet/plume, in order to compare to
the present near-field prediction.
Page 3

MULTI_6_20180524.ses
REMINDER: The user must take note that HYDRODYNAMIC MODELING by any known
technique is NOT AN EXACT SCIENCE.
Extensive comparison with field and laboratory data has shown that the
CORMIX predictions on dilutions and concentrations (with associated
plume geometries) are reliable for the majority of cases and are accurate
to within about +-50% (standard deviation) .
As a further safeguard, CORMIX will not give predictions whenever it judges
the design configuration as highly complex and uncertain for prediction.
Page 4

MULTI_6_20180524.prd
CORMIX2 PREDICTION FILE:
222222222222222222222222222222222222222222222222222222222222222222222222222222
22222222222222222
CORMIX MIXING ZONE EXPERT SYSTEM
Subsystem CORMIX2: Multiport Diffuser Discharges
CORMIX Version 10.OGT
HYDRO2 Version 10.0.0.0 July 2016
CASE DESCRIPTION
Site name/label : EMERALD ISLE BOAT RAMP
Design case: MULTI 6
FILE NAME: Z:\. . .RMIX Runs\CORMIX Model Files\MULTI_6_20180524.prd
Time stamp: 06/19/2018--13:48:05
ENVIRONMENT PARAMETERS (metric units)
Bounded section
BS = 253.00 AS = 310.00 QA = 53.27 ICHREG= 1
HA = 1.23 HD = 1.31
Tidal Simulation at TIME = 1.000 h
PERIOD= 12.31 h UAmax = 0.324 dUa/dt= 0.172 (m/s)/h
UA = 0.172 F = 0.046 USTAR =0.1301E-01
UW = 2.629 UWSTAR=0.2933E-02
Uniform density environment
STRCND= U RHOAM = 1016.6700
DIFFUSER DISCHARGE PARAMETERS (metric units)
Diffuser type: DITYPE= staged_perpendicular
BANK = RIGHT DISTB = 108.05 YB1 = 105.00 YB2 = 111.10
LD = 6.10 NOPEN = 3 SPAC = 3.05
DO = 0.076 AO = 0.005 HO = 0.25 SUBO = 1.06
DOINP = 0.076 CRO = 1.000
Nozzle/port arrangement: staged
GAMMA = 90.00 THETA = 5.00 SIGMA = 90.00 BETA = 0.00
UO = 3.841 QO = 0.053 QOA =0.5255E-01
RHO() = 1006.6100 DRHOO =0.1006E+02 GPO =0.9704E-01
CO =0. 5000E+01 CUNITS= mg/1
IPOLL = 1 KS =0.0000E+00 KD =0.0000E+00
FLUX VARIABLES - PER UNIT DIFFUSER LENGTH (metric units)
q0 =0.8621E-02 m0 =0.3312E-01 j0 =0.8366E-03 SIGNJO= 1.0
Associated 2-d length scales (meters)
1Q=B = 0.002 1M = 3.73 lm = 1.12
lmp = 99999.00 lbp = 99999.00 la = 99999.00
FLUX VARIABLES - ENTIRE DIFFUSER (metric units)
QO =0.5255E-01 MO =0.2019E+00 JO =0. 5100E-02
Associated 3-d length scales (meters)
LQ = 0.07 LM = 4.22 Lm = 2.61 Lb = 1.00
Lmp = 99999.00 Lbp = 99999.00
Tidal : Tu = 0.1617 h Lu = 16.171 Lmin = 1.387
NON-DIMENSIONAL PARAMETERS
FRO = 260.30 FRDO = 44.67 R = 22.35 PL = 36.10
(slot) (port/nozzle)
FLOW CLASSIFICATION
222222222222222222222222222222222222222222
2 Flow class (CORMIX2) = MU6 2
2 Applicable layer depth HS = 1. 31 2
2 Limiting Dilution S =QA/QO= 1014.69 2
222222222222222222222222222222222222222222
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MULTI_6_20180524.prd
MIXING ZONE / TOXIC DILUTION / REGION OF INTEREST PARAMETERS
CO =0.5000E+01 CUNITS= mg/1
NTOX = 0
NSTD = 1 CSTD =0.2000E+01
REGMZ = 1
REGSPC= 1 XREG = 10.00 WREG = 0.00 AREG = 0.00
XINT = 2530.00 XMAX = 2530.00
X-Y-Z COORDINATE SYSTEM:
ORIGIN is located at the bottom and the diffuser mid-point:
108.05 m from the RIGHT bank/shore.
X-axis points downstream, Y-axis points to left, z-axis points upward.
NSTEP = 100 display intervals per module
BEGIN MOD202: DISCHARGE MODULE (STAGED DIFFUSER)
Due to complex near-field motions: EQUIVALENT SLOT DIFFUSER (2-D) GEOMETRY
Profile definitions:
BV = Gaussian 1/e (37%) half-width, in vertical plane normal to trajectory
BH = Gaussian 1/e (37%) half-width in horizontal plane normal to trajectory
S = hydrodynamic centerline dilution
C = centerline concentration (includes reaction effects, if any)
Uc = Local centerline excess velocity (above ambient)
TT = Cumulative travel time
X Y Z S C BV BH Uc
TT
0.00 0.00 0.25 1.0 0. 500E+01 0.00 3.05 3.841
.00000E+00
END OF MOD202: DISCHARGE MODULE (STAGED DIFFUSER)
BEGIN MOD275: STAGED PERPENDICULAR DIFFUSER IN STRONG CURRENT
Because of the strong ambient current the diffuser plume of this crossflowing
discharge gets RAPIDLY DEFLECTED.
A near-field zone is formed that is VERTICALLY FULLY MIXED over the entire
layer depth. Full mixing is achieved at a downstream distance of about
five (5) layer depths.
Profile definitions:
BV = layer depth (vertically mixed)
BH = top-hat half-width, measured horizontally in Y-direction
S = hydrodynamic average (bulk) dilution
C = average (bulk) concentration (includes reaction effects, if any)
TT = Cumulative travel time
X Y Z S C BV BH TT
0.00 0.00 0.25 1.0 0. 500E+01 0.00 3.05 .00000E+00
** WATER QUALITY STANDARD OR CCC HAS BEEN FOUND **
The pollutant concentration in the plume falls below water quality standard
or CCC value of 0.200E+01 in the current prediction interval .
This is the spatial extent of concentrations exceeding the water quality
standard or CCC value.
0.07 0.03 0.26 4.0 0.126E+01 0.02 3.05 .38133E+00
0.13 0.05 0.26 5.2 0.962E+00 0.03 3.06 .76267E+00
0.20 0.08 0.27 6.1 0.815E+00 0.04 3.06 .11440E+01
0.26 0.10 0.27 6.9 0.722E+00 0.05 3.07 .15253E+01
0.33 0.13 0.27 7.6 0.656E+00 0.07 3.07 .19067E+01
Page 2

MULTI_6_20180524.prd
0.39 0.16 0.28 8.3 0.606E+00 0.08 3.08 .22880E+01
0.46 0.18 0.28 8.8 0. 566E+00 0.09 3.09 .26693E+01
0.52 0.21 0.29 9.4 0. 534E+00 0.11 3.09 .30507E+01
0.59 0.23 0.29 9.9 0. 506E+00 0.12 3.10 .34320E+01
0.66 0.26 0.29 10.3 0.483E+00 0.13 3.10 .38133E+01
0.72 0.29 0.30 10.8 0.463E+00 0.15 3.11 .41947E+01
0.79 0.31 0.30 11.2 0.445E+00 0.16 3.11 .45760E+01
0.85 0.34 0.31 11.6 0.429E+00 0.17 3.12 .49574E+01
0.92 0.37 0.31 12.0 0.415E+00 0.19 3.12 .53387E+01
0.98 0.39 0.31 12.4 0.403E+00 0.20 3.13 .57200E+01
1.05 0.42 0.32 12.8 0. 391E+00 0.21 3.13 .61014E+01
1.11 0.44 0.32 13.1 0.380E+00 0.22 3.14 .64827E+01
1.18 0.47 0.33 13. 5 0.371E+00 0.24 3.15 .68640E+01
1.25 0. 50 0.33 13.8 0.362E+00 0.25 3.15 .72454E+01
1.31 0. 52 0.33 14.2 0.353E+00 0.26 3.16 .76267E+01
1.38 0. 55 0.34 14. 5 0.345E+00 0.28 3.16 .80080E+01
1.44 0. 57 0.34 14.8 0.338E+00 0.29 3.17 .83894E+01
1.51 0.60 0.35 15.1 0.331E+00 0.30 3.17 .87707E+01
1. 57 0.63 0.35 15.4 0.325E+00 0.32 3.18 .91520E+01
1.64 0.65 0.35 15.7 0.319E+00 0.33 3.18 .95334E+01
1.70 0.68 0.36 16.0 0.313E+00 0.34 3.19 .99147E+01
1.77 0.70 0.36 16.2 0.308E+00 0.36 3.19 .10296E+02
1.83 0.73 0.37 16. 5 0.303E+00 0.37 3.20 .10677E+02
1.90 0.76 0.37 16.8 0.298E+00 0.38 3.20 .11059E+02
1.97 0.78 0.37 17.0 0.294E+00 0.39 3.21 .11440E+02
2.03 0.81 0.38 17.3 0.289E+00 0.41 3.22 .11821E+02
2.10 0.83 0.38 17. 5 0.285E+00 0.42 3.22 .12203E+02
2.16 0.86 0.39 17.8 0.281E+00 0.43 3.23 .12584E+02
2.23 0.89 0.39 18.0 0.277E+00 0.45 3.23 .12965E+02
2.29 0.91 0.39 18.3 0.274E+00 0.46 3.24 .13347E+02
2.36 0.94 0.40 18. 5 0.270E+00 0.47 3.24 .13728E+02
2.42 0.96 0.40 18.7 0.267E+00 0.49 3.25 .14109E+02 1
2.49 0.99 0.41 19.0 0.264E+00 0. 50 3.25 .14491E+02 1
2. 56 1.02 0.41 19.2 0.261E+00 0. 51 3.26 .14872E+02
2.62 1.04 0.41 19.4 0.258E+00 0. 53 3.26 .15253E+02
2.69 1.07 0.42 19.6 0.255E+00 0. 54 3.27 .15635E+02
2.75 1.10 0.42 19.9 0.252E+00 0. 55 3.27 .16016E+02
2.82 1.12 0.43 20.1 0.249E+00 0. 56 3.28 .16397E+02
2.88 1.15 0.43 20.3 0.247E+00 0. 58 3.29 .16779E+02
2.95 1.17 0.43 20.5 0.244E+00 0. 59 3.29 .17160E+02
3.01 1.20 0.44 20.7 0.242E+00 0.60 3.30 .17541E+02
3.08 1.23 0.44 20.9 0.239E+00 0.62 3.30 .17923E+02
3.15 1.25 0.45 21.1 0.237E+00 0.63 3.31 .18304E+02
3.21 1.28 0.45 21.3 0.235E+00 0.64 3.31 .18685E+02
3.28 1.30 0.45 21. 5 0.233E+00 0.66 3.32 .19067E+02
3.34 1.33 0.46 21.7 0.231E+00 0.67 3.32 .19448E+02
3.41 1.36 0.46 21.9 0.229E+00 0.68 3.33 .19829E+02
3.47 1.38 0.47 22.1 0.227E+00 0.70 3.33 .20211E+02
3. 54 1.41 0.47 22.2 0.225E+00 0.71 3.34 .20592E+02
3.60 1.43 0.47 22.4 0.223E+00 0.72 3.34 .20973E+02
3.67 1.46 0.48 22.6 0.221E+00 0.73 3.35 .21355E+02
3.74 1.49 0.48 22.8 0.219E+00 0.75 3.36 .21736E+02
3.80 1. 51 0.49 23.0 0.218E+00 0.76 3.36 .22117E+02
3.87 1. 54 0.49 23.2 0.216E+00 0.77 3.37 .22499E+02
3.93 1. 56 0.49 23.3 0.214E+00 0.79 3.37 .22880E+02
4.00 1. 59 0. 50 23. 5 0.213E+00 0.80 3.38 .23261E+02
4.06 1.62 0.50 23.7 0.211E+00 0.81 3.38 .23643E+02
4.13 1.64 0. 51 23.9 0.210E+00 0.83 3.39 .24024E+02
4.19 1.67 0. 51 24.0 0.208E+00 0.84 3.39 .24405E+02
4.26 1.70 0. 51 24.2 0.207E+00 0.85 3.40 .24787E+02
4.33 1.72 0. 52 24.4 0.205E+00 0.87 3.40 .25168E+02
4.39 1.75 0. 52 24.5 0.204E+00 0.88 3.41 .25549E+02
4.46 1.77 0. 53 24.7 0.203E+00 0.89 3.41 .25931E+02
4. 52 1.80 0. 53 24.8 0.201E+00 0.91 3.42 .26312E+02
4. 59 1.83 0. 53 25.0 0.200E+00 0.92 3.43 .26693E+02
4.65 1.85 0.54 25.2 0.199E+00 0.93 3.43 .27075E+02
Page 3

MULTI_6_20180524.prd
4.72 1.88 0. 54 25.3 0.197E+00 0.94 3.44 .27456E+02
4.78 1.90 0. 55 25. 5 0.196E+00 0.96 3.44 .27837E+02
4.85 1.93 0. 55 25.6 0.195E+00 0.97 3.45 .28219E+02
4.91 1.96 0. 55 25.8 0.194E+00 0.98 3.45 .28600E+02
4.98 1.98 0. 56 25.9 0.193E+00 1.00 3.46 .28981E+02
5.05 2.01 0. 56 26.1 0.192E+00 1.01 3.46 .29363E+02
5.11 2.03 0. 57 26.2 0.191E+00 1.02 3.47 .29744E+02
5.18 2.06 0. 57 26.4 0.189E+00 1.04 3.47 .30125E+02
5.24 2.09 0.58 26. 5 0.188E+00 1.05 3.48 .30507E+02
5.31 2.11 0.58 26.7 0.187E+00 1.06 3.48 .30888E+02
5.37 2.14 0. 58 26.8 0.186E+00 1.08 3.49 .31269E+02
5.44 2.16 0. 59 27.0 0.185E+00 1.09 3.50 .31651E+02
5. 50 2.19 0.59 27.1 0.184E+00 1.10 3.50 .32032E+02
5. 57 2.22 0.60 27.3 0.183E+00 1.11 3. 51 .32413E+02
5.64 2.24 0.60 27.4 0.182E+00 1.13 3. 51 .32795E+02
5.70 2.27 0.60 27. 5 0.182E+00 1.14 3. 52 .33176E+02
5.77 2.29 0.61 27.7 0.181E+00 1.15 3. 52 .33557E+02
5.83 2.32 0.61 27.8 0.180E+00 1.17 3.53 .33939E+02
5.90 2.35 0.62 28.0 0.179E+00 1.18 3.53 .34320E+02
5.96 2.37 0.62 28.1 0.178E+00 1.19 3.54 .34701E+02
6.03 2.40 0.62 28.2 0.177E+00 1.21 3.54 .35083E+02
6.09 2.43 0.63 28.4 0.176E+00 1.22 3. 55 .35464E+02
6.16 4
2.45 0.63 28. 5 0.175E+00 1.23 3. 55 .358 5E+0 2
6.23 2.48 0.64 28.6 0.175E+00 1.25 3. 56 .36227E+02
6.29 2.50 0.64 28.8 0.174E+00 1.26 3. 57 .36608E+02
6.36 2.53 0.64 28.9 0.173E+00 1.27 3. 57 .36990E+02
6.42 2.56 0.65 29.0 0.172E+00 1.28 3. 58 .37371E+02
6.49 2.58 0.65 29.2 0.171E+00 1.30 3. 58 .37752E+02
6.55 2.61 0.66 29.3 0.171E+00 1.31 3.59 .38134E+02
Cumulative travel time = 38.1335 sec ( 0.01 hrs)
Plume centerline may exhibit slight discontinuities in transition
to subsequent far-field module.
END OF MOD275: STAGED PERPENDICULAR DIFFUSER IN STRONG CURRENT
** End of NEAR-FIELD REGION (NFR) **
BEGIN MOD241: BUOYANT AMBIENT SPREADING
Profile definitions:
BV = top-hat thickness, measured vertically
BH = top-hat half-width, measured horizontally in y-direction
ZU = upper plume boundary (z-coordinate)
ZL = lower plume boundary (z-coordinate)
S = hydrodynamic average (bulk) dilution
C = average (bulk) concentration (includes reaction effects, if any)
TT = Cumulative travel time
Plume Stage 1 (not bank attached) :
X Y Z S C BV BH ZU ZL
TT
6.55 2.61 1.31 29.3 0.171E+00 1.31 3. 59 1.31 0.00
.38134E+02
9. 57 2.61 1.31 30.2 0.165E+00 1.14 4.34 1.31 0.17
.55656E+02
** REGULATORY MIXING ZONE BOUNDARY **
In this prediction interval the plume DOWNSTREAM distance meets or exceeds
the regulatory value = 10.00 m.
This is the extent of the REGULATORY MIXING ZONE.
12. 58 2.61 1.31 30.9 0.162E+00 1.02 5.04 1.31 0.29
.73179E+02
15.60 2.61 1.31 31.4 0.159E+00 0.93 5.69 1.31 0.38
.90702E+02
18.61 2.61 1.31 31.9 0.157E+00 0.87 6.31 1.31 0.44
Page 4

MULTI_6_20180524.prd
.10822E+03
21.62 2.61 1.31 32.3 0.155E+00 0.82 6.89 1.31 0.49
.12575E+03
24.64 2.61 1.31 32.6 0.153E+00 0.77 7.45 1.31 0. 54
.14327E+03
27.65 2.61 1.31 32.9 0.152E+00 0.74 8.00 1.31 0. 57
.16079E+03
30.67 2.61 1.31 33.2 0.150E+00 0.71 8. 52 1.31 0.60
.17832E+03
33.68 2.61 1.31 33. 5 0.149E+00 0.69 9.03 1.31 0.63
.19584E+03
36.70 2.61 1.31 33.9 0.148E+00 0.66 9.52 1.31 0.65
.21336E+03
39.71 2.61 1.31 34.2 0.146E+00 0.65 10.00 1.31 0.67
.23088E+03
42.72 2.61 1.31 34.6 0.145E+00 0.63 10.47 1.31 0.68
.24841E+03
45.74 2.61 1.31 34.9 0.143E+00 0.62 10.93 1.31 0.69
.26593E+03
48.75 2.61 1.31 35.3 0.142E+00 0.60 11.38 1.31 0.71
.28345E+03
51.77 2.61 1.31 35.7 0.140E+00 0.59 11.82 1.31 0.72
.30098E+03
54.78 2.61 1.31 36.2 0.138E+00 0.59 12.25 1.31 0.72
.31850E+03
57.80 2.61 1.31 36.6 0.136E+00 0.58 12.67 1.31 0.73
.33602E+03
60.81 2.61 1.31 37.1 0.135E+00 0.57 13.09 1.31 0.74
.35354E+03
63.82 2.61 1.31 37.7 0.133E+00 0. 57 13.50 1.31 0.74
.37107E+03
66.84 2.61 1.31 38.2 0.131E+00 0. 56 13.91 1.31 0.75
.38859E+03
69.85 2.61 1.31 38.8 0.129E+00 0. 56 14.31 1.31 0.75
.40611E+03
72.87 2.61 1.31 39.4 0.127E+00 0. 56 14.70 1.31 0.75
.42363E+03
75.88 2.61 1.31 40.1 0.125E+00 0. 56 15.09 1.31 0.76
.44116E+03
78.89 2.61 1.31 40.7 0.123E+00 0. 55 15.47 1.31 0.76
.45868E+03
81.91 2.61 1.31 41. 5 0.121E+00 0. 55 15.85 1.31 0.76
.47620E+03
84.92 2.61 1.31 42.2 0.118E+00 0. 55 16.22 1.31 0.76
.49373E+03
87.94 2.61 1.31 43.0 0.116E+00 0. 55 16.59 1.31 0.76
. 51125E+03
90.95 2.61 1.31 43.8 0.114E+00 0. 56 16.95 1.31 0.76
. 52877E+03
93.97 2.61 1.31 44.6 0.112E+00 0. 56 17.31 1.31 0.75
. 54629E+03
96.98 2.61 1.31 45.5 0.110E+00 0. 56 17.67 1.31 0.75
. 56382E+03
98.46 2.61 1.31 46.0 0.109E+00 0. 56 17.85 1.31 0.75
. 57243E+03
Cumulative travel time = 572.4307 sec ( 0.16 hrs)
CORMIX prediction has been TERMINATED at last prediction interval .
Limiting time due to TIDAL REVERSAL has been reached.
END OF MOD241: BUOYANT AMBIENT SPREADING
CORMIX2: Multiport Diffuser Discharges End of Prediction File
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222222222222222222222222222222222222222222222222222222222222222222222222222222
22222222222222222
Page 6

VERT5_RISE_CONSTRICT_20180516.ses
thickness (bv) = 0.33 m
Cumulative travel time: 53.6586 sec.
Note:
Plume concentration c and dilution s values are reported based on prediction
file values - assuming linear interpolation between predicted points just
before and just after the RMZ boundary has been detected.
Please ensure a small step size is used in the prediction file to account
for this linear interpolation. Step size can be controlled by increasing
(reduces the prediction step size) or decreasing (increases the prediction
step size) the - Output Steps per Module - in CORMIX input.
At this position, the plume is NOT IN CONTACT with any bank.
Furthermore, the specified water quality standard has indeed been met
within the RMZ. In particular:
The ambient water quality standard was encountered at the following
plume position:
water quality standard = 2 mg/1
Corresponding dilution s = 2.5
Plume location: x = 0.32 m
(centerline coordinates) y = 1.95 m
z = 0. 51 m
Plume dimension: half-width (bh) = 0.28 m
********** FINAL DESIGN ADVICE AND COMMENTS . *******. ..... ... "****
REMINDER: The user must take note that HYDRODYNAMIC MODELING by any known
technique is NOT AN EXACT SCIENCE.
Extensive comparison with field and laboratory data has shown that the
CORMIX predictions on dilutions and concentrations (with associated
plume geometries) are reliable for the majority of cases and are accurate
to within about +-50% (standard deviation) .
As a further safeguard, CORMIX will not give predictions whenever it judges
the design configuration as highly complex and uncertain for prediction.
Page 3
L