20150124 Ver 2_Final DO Monitoring Plan_20190118

Bynum Hydro Project
FERC Project No. P-14858
DWR Project # 2015-0124 v2

WATER QUALITY MONITORING PLAN

Prepared by:
McMahan Hydroelectric, LLC

Andrew McMahan, President
[e-mail]
105 Durham Eubanks Rd.
Pittsboro, NC 27312
336-509-2148

January 2019
Water Quality Monitoring Plan FERC No. P-4093 Bynum Hydro Project McMahan Hydroelectric, LLC
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Table of Contents:
Acronyms ....................................................................................................................................................................3
Purpose .......................................................................................................................................................................4
Background .................................................................................................................................................................5
General Description of the Haw River in Project Area ...........................................................................................5
Water Quality Classifications and Standards .........................................................................................................6
Historic River Data ..................................................................................................................................................7
Monitoring Approach and Parameters .......................................................................................................................9
Pre-operational Monitoring ...................................................................................................................................9
Post-operational Monitoring ..................................................................................................................................9
Sites, Frequency, and Duration ..................................................................................................................................9
Descriptions of Sampling and Monitoring Locations........................................................................................... 10
Sampling Procedure ................................................................................................................................................ 11
Equipment Calibration & Maintenance ............................................................................................................... 11
Data Management and Reporting ........................................................................................................................... 11

List of Figures:
Figure 1 - View of Project Area ...................................................................................................................................5
Figure 2 - AU Numbers Located within Project Area ..................................................................................................6
Figure 3 - DO Levels at AMS Station B210000 1980-2016 .........................................................................................7
Figure 4- Average Monthly DO Level 1968-2016 .......................................................................................................8
Figure 5- Average Monthly Water Temperature 1968-2016 .....................................................................................8
Figure 6 - DO & Water Temperature at AMS Station B210000 1997-2016 ...............................................................8
Figure 7 - Proposed Monitoring Locations .............................................................................................................. 10

List of Tables:
Table 1 - Monitoring Site Data ................................................................................................................................ 11

Water Quality Monitoring Plan FERC No. P-4093 Bynum Hydro Project McMahan Hydroelectric, LLC
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Acronyms
WQMP Water Quality Monitoring Plan
NCDWR North Carolina Division of Water Resources
Division North Carolina Division of Water Resources
NCDENR North Carolina Department of Environment and Natural Resources
FERC Federal Energy Regulatory Commission
Commission Federal Energy Regulatory Commission
McMahan McMahan Hydroelectric, LLC
Applicant McMahan Hydroelectric, LLC
Project Bynum Hydro Project (FERC P-4093)
USGS United States Geological Survey
AMS Ambient Monitoring System
GPS Global Positioning System
SOP Standard Operating Procedure
DO Dissolved oxygen
°C Degrees Centigrade
°F Degrees Fahrenheit
AU# Assessment Unit Number
cfs Cubic Feet Per Second
m Meter
mg/L Milligrams Per Liter

Water Quality Monitoring Plan FERC No. P-4093 Bynum Hydro Project McMahan Hydroelectric, LLC
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Purpose
This Water Quality Monitoring Plan (WQMP) describes monitoring procedures for select water quality
parameters in the vicinity of the Bynum Hydro Project (Project) (No. P-4093). The Project is located on
the Haw River in Chatham County, North Carolina. The Project consists of a dam (Bynum Dam), an
impoundment (Bynum Reservoir aka Odell Pond), an open millrace, a powerhouse and associated
equipment, and transmission facilities.
McMahan is in the process of relicensing the Bynum Hydro Project from the Federal Energy Regulatory
Commission (FERC). The FERC is expected to issue a new license before the end of 2018. To support
issuance of the license from the FERC, McMahan is required to obtain a 401 Water Quality Certification
from the Division of Water Resources (DWR) of the North Carolina Department of Environment and
Natural Resources (NCDENR).
As will be stipulated in the FERC license once issued to McMahan, McMahan will conduct monitoring of
water quality conditions in the Haw River in the vicinity of the Project to ensure continued protection
and compliance with state water quality standards. McMahan’s plan for water quality monitoring is
described in the following sections, including sites and parameters to be monitored, sampling frequency,
sampling procedures and equipment, quality control procedures, and data assessment and reporting.

Water Quality Monitoring Plan FERC No. P-4093 Bynum Hydro Project McMahan Hydroelectric, LLC
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Background
The Project is located at river mile 101 on the Haw River in the Cape Fear River Basin and consists of one
development. Project lands are located entirely within Chatham County, North Carolina. The project
utilizes an existing dam approximately 10 feet tall and 900 feet long; consisting of a 750-foot section of
spillway and 150-foot non-overflow section along the eastern side of the river. The non-overflow section
of the dam contains two Tainter-style gates that regulate water inflow to the open millrace. The dam
associated with the project is not federally owned or operated. The powerhouse consists of one
generator/turbine unit with a generating capacity of 600kW. The project will be operated in run-of-the-
river mode at all times with manual start and automatic stop. No federal lands are affected by the
project.
General Description of the Haw River in Project Area
The 20-acre reservoir at the project site contains multiple small rocky islands and is relatively shallow
with limited habitat due to the trapping of silt at the impoundment. Waters below the impoundment
are predominately rocky riverbed with numerous islands that create a braided nature to the river, but
consists of one main channel and a smaller channel toward the eastern side of the river (Figure 1).
The closest upstream impoundment is located approximately 15 miles away at Saxapahaw. The closest
downstream impoundment is located at Jordan Lake approximately 6 miles away.
The project utilizes a 2,500 ft bypass reach below the dam on the eastern side of the river. The intake
canal for the project begins at the impoundment and flows parallel to the river along the eastern bank
until it reaches the powerhouse. After passing through the powerhouse water flows down a 500 ft
tailrace before rejoining the river.

Figure 1 - View of Project Area
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Water Quality Classifications and Standards
NCDWR uses assessment unit numbers (AU#)
to identify segments of waterways in North
Carolina for the purpose of tracking and
recording water quality assessment in a state
database. Three NCDWR assessment unit
index numbers have been identified for
waters within the project area (Figure 2).
The first section, AU# 16-(28.75), begins
approximately 0.15 miles west of U.S.
15/501, to a point 0.5 miles upstream of the
Town of Pittsboro current water supply
intake at the project impoundment. NCDENR
classified this river reach as a water supply
(WS-IV)1 and a nutrient sensitive water (NSW)2.
The second section, AU# 16-(28.875), begins 0.15 miles upstream of US 15/501 at the Town of Pittsboro
water supply intake and ends 0.4 miles downstream of Brooks Branch. NCDENR classified this river reach
as WS-IV and NSW.
The third section, AU #16-(36.3), begins 0.4 miles downstream of Brooks Branch and ends at the former
Pittsboro water supply intake located 0.3 miles upstream of Pokeberry Creek. This reach is cl assified as
WS-IV and NSW, as well as a critical area (CA).
According to 15A NCAC 0.2B .0202, all waters of the Cape Fear River Basin are classified as lower
piedmont and coastal plain waters. As such, the waters associated with the hydroelectric plant ar e
subject to the following water quality standards: a minimum instantaneous dissolved oxygen (DO)
concentration of 4.0 mg/L, a minimum daily average DO concentration of 5.0 mg/L, a maximum
temperature increase of 2.8°C above natural water temperature, and a maximum water temperature of
32° C.

1 Waters classified as WS-IV are waters used as sources of water supply for drinking, culinary, or food processing purposes where a WS-I, II
or III classification is not feasible. These waters are also protected for Class C uses. WS-IV waters are generally in moderately to highly
developed watersheds or Protected Areas.
Class C waters are protected for uses such as secondary recreation, fishing, wildlife, fish consumption, aquatic life including propagation,
survival and maintenance of biological integrity, and agriculture. Secondary recreation includes wading, boating, and other uses involving
human body contact with water where such activities take place in an infrequent, unorganized, or incidental manner.
2 In 1983, all waters in the Haw River watershed (subbasins 03-06-01 to 03-06-06) including Jordan Reservoir received a supplemental
classification of nutrient sensitive water (NSW) to acknowledge that Jordan Reservoir could have water quality problems associated
with excessive nutrient inputs from both wastewater discharges and runoff from the various land uses in the watershed.
Figure 2 - AU Numbers Located within Project Area
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Historic River Data
Data has been collected on a regular basis within the project vicinity for at least 40 years through two
sources; a river gage station operated by the United States Geologic Survey (USGS), and an Ambient
Monitoring Station overseen by the North Carolina Division of Water Resources.
USGS Gauge Station
The USGS maintained a river gage station located (35°45’55” N, 79°08’09” W) on the Haw River
approximately one mile downstream from the Project dam. USGS Gauge 02096960 – Haw River Near
Bynum, NC references 1,275 square miles of drainage area and is 283.31 feet above sea level. The USGS
station at Bynum was installed in 1973 and remains in operation.
The USGS station near Bynum currently collects data on water discharge and gage height in 15 minute
increments. Discharge data has been collected since 1973. Gage height data is available back to 19 96.
NCDWQ Ambient Monitoring System
The North Carolina DWR has conducted water quality monitoring within the project boundary for over
40 years through the state’s Ambient Monitoring System (AMS). Station number B2100000 (35.77°N,
79.14° W) is located on the Haw River at State Road 1713 in Bynum. A full suite of water quality testing
is conducted at the station.
Data regarding DO levels and water temperature have been collected at this station since 1968.
Monitoring was limited to warm weather months throughout the 1970s. Year-round monthly monitoring
began at the station in 1980 and continued until 2005. Since 2005 monitoring at the station has been
conducted on bi-weekly basis. Approximately 600 measurements for DO and water temperature have
been conducted since data collection begin at AMS B2100000 in 1968.
Analysis of Historic Water Monitoring Data
Analysis of DO and water temperature data from AMS station B2100000 reveals the close relationship
between water temperature and DO at this site. DO at this site show an annual pattern of decreased
DO levels during the summer season and increased DO levels du ring the winter season (Figure 3).

Figure 3 - DO Levels at AMS Station B210000 1980-2016

0
5
10
15
20
Dissolved Oxygen (mg/L)Dissolved Oxygen Level at AMS Station B210000 1980-2016
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This pattern of annually fluctuating DO levels is further demonstrated when historic averages are
calculated for each month of the year. According to these results, average monthly DO levels range from
a low of 7.6 mg/L during July to a high of 13.0 mg/L in January for the years 1968-2016 (Figure 4).
Figure 4- Average Monthly DO Level 1968-2016

Figure 5- Average Monthly Water Temperature 1968-2016

Water temperature data collected at AMS Station B2100000 also present an annual pattern with warmer
temperatures in the summer season and cooler temperatures in the winter season (Figure 6). Monthly
averages for water temperature at this site reflect this cycle (Figure 5).
Figure 6 - DO & Water Temperature at AMS Station B210000 1997-2016

13.0 12.4
11.3
9.7 8.9 8.1 7.6 7.9 8.3
9.7
11.0
12.3
0.0
3.0
6.0
9.0
12.0
15.0
JanFebMarAprMayJunJulAugSepOctNovDecmg/LMonth
Average Monthly DO Levels at Bynum
1968-2016
5.6
7.3
11.3
16.8
21.3
25.7
27.7 27.5
23.8
17.6
11.8
7.3
0.0
5.0
10.0
15.0
20.0
25.0
30.0
JanFebMarAprMayJunJulAugSepOctNovDecDegree CelciusMonth
Average Monthly Water Temp at Bynum
1968-2016
0
5
10
15
20
25
30
35
0
2
4
6
8
10
12
14
16
18
Temperature °Cmg/LDissolved Oxygen and Water Temperature at AMS Station B2100000 for 1997 -2016
Dissolved Oxygen Level Water Temperature
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Monitoring Approach and Parameters
McMahan seeks to conduct water quality monitoring at an appropriate scale for the project. Site
selection for water quality monitoring at this project is based on 1) locations that will help characterize
conditions in the bypass reach and the tailrace; and 2) locations that are safe and accessible for data
collection.
The approach McMahan proposes would address monitoring water quality within the Project area as
two phases: Pre-operational monitoring and Post-operational monitoring.
Pre-operational Monitoring
As stated in the previous section, water quality data has been collected within the Project area by
NCDWR for over 40 years.
McMahan proposes to conduct no additional water quality monitoring prior to operation on the
hydroelectric project.
Post-operational Monitoring
Once the hydroelectric facility is operational, McMahan proposes to assess two water quality parameters
(DO and Water Temperature) at three sampling sites within the Project area as well as physical
measurements of stream discharge and river gauge height. DO and water temperature will be recorded
using a handheld instrument (YSI ProODO Optical Dissolved Oxygen Instrument or similar), while stream
discharge and river height will be monitored using the USGS Gauging Station #02096960 (Haw River Near
Bynum.) Monitoring of these parameters at the selected sites will allow McMahan and the Division to
assess on-going trends in water quality conditions and compliance with applicable water quality
standards in the Project area.
Sites, Frequency, and Duration
The three sampling sites and their locations are shown in Figure 7. The sampling sites are located on
the Haw River within two segments in the Project vicinity:
• In the bypass section of the Haw River; from the toe of the Bynum dam down to the confluence of
the project tailrace and bypass section of the river.
• In the project tailrace
Parameters and sampling frequency are summarized in Table 1. In general, the sampling sites are
selected for their ability to represent conditions within these segments, and to ascertain potential
effects of Project facilities and operations on water quality , while also providing safe monitoring
locations for the field operator.

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Figure 7 - Proposed Monitoring Locations

Descriptions of Sampling and Monitoring Locations
Bypass Reach
Water quality monitoring will occur at two site within the project bypass reach. Monitoring for both of
these sites will be conducted from the Bynum Road (SR 1713) pedestrian bridge located approximately
1750 feet downstream of the Bynum dam and 750 feet upstream from the confluence of the
powerhouse tailrace with the Haw River. The “Bypass Reach 2” monitoring location identified in Figure
7 is the same location used by the DWR for its ambient water quality monitoring of the Haw River in
Bynum.
Powerhouse Tailrace
Tailrace monitoring of water temperature and dissolved oxygen will occur at a site located downstream
of the powerhouse within the tailrace. Exact location of the monitoring site within the tailrace has yet
to be determined. McMahan will consult with DWR and other resource agencies to determine an
appropriate monitoring location.
USGS River Gauging Station
The (USGS) maintains a USGS river gauge located (35°45’55” N, 79°08’09” W) on the Haw River
approximately one mile down river from the Project dam. USGS Gauge 02096960 – Haw River Near
Bynum, NC references 1,275 square miles of drainage area and is 283.31 feet above sea level. For flow
information utilized in this monitoring plan a direct drainage area percentage factor of 1:1 was used to
convert recorded USGS flow data to historic water flow rates at the Bynum Dam.

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Table 1 – Water Quality Monitoring Site Data
Sample Site Bypass Reach 1 Bypass Reach 2 Powerhouse Tailrace
Site Identification Name BR-1 BR-2 PT-1
Site Location
From the SR 1713
pedestrian bridge.
In the middle of the
eastern channel.
From the SR 1713
pedestrian bridge.
In the middle of the
main river channel.
In the project tailrace
directly downstream
from the powerhouse
GPS Coordinates 35°46’20.71” N
79°8’39.39” W
35°46’18.29” N
79°8’41.92” W
35°46’18.93” N
79°8’33.93” W
Monitoring Parameters Dissolved Oxygen /
Temperature
Dissolved Oxygen /
Temperature
Dissolved Oxygen /
Temperature
Frequency of Monitoring Weekly* Weekly* Weekly*
Duration of Monitoring Year Round Year Round Year Round
Sampling Method Hand-held Instrument Hand-held Instrument Hand-held Instrument
* Sampling will only be collected when the powerhouse is operational within that one-week period.
Sampling Procedure
Procedure for field sampling, data collection, equipment calibration, equipment cleaning, and other
monitoring activities will follow, or adapt as appropriate, the Standard Operations Procedures provided
by the NC DWR Intensive Survey Branch SOP Manual for Physical and Chemical Monitoring. These are
the same procedures used by DWR for water quality monitoring.
Field sampling will be conducted at all of the proposed monitoring sites on the same day when the
powerhouse is in operation.
Equipment Calibration & Maintenance
In addition to following SOPs provided by AMS, monitoring equipment will be calibrated, cleaned, and
maintained in accordance with the manufacturer’s specifications. A record of calibration measurements
will be maintained to ensure proper instrument operation. Any instrument that fails to properly
maintain calibration will not be used for data collection.
Data Management and Reporting
McMahan will maintain digital records of all recorded data as well as a backup of collected data in cloud
storage. McMahan will provide data on an annual basis, or as requested, to NCDWQ and other
appropriate agencies.