NC0004979_Temperature Impairment_20100203

Belnick, Tom
From:
Lewis, Ron [[e-mail]]
Sent:
Wednesday, February 03, 2010 9:04 PM
To:
Belnick, Tom
Cc:
Williams, Melanie; Chernikov, Sergei
Subject:
RE: Temperature Impairment
Attachments:
Allen 316a demo.pdf
Tom,
Please see pages 27 and 31 in the attached Allen Steam Station 316(a) demonstration that references the mixing zone
that was originally assigned per the NPDES permit. However, the demonstration supported that a variance of the
thermal water quality standards be granted because confining heat dissipation to the assigned mixing zone would
essentially be impossible. If further documentation is needed to address this issue, I will need to start searching the
archived files.
Thanks,
Ron Lewis
Duke Energy
Mail Code: EC13K
526 S. Church Street
Charlotte, NC 28202
Office 980-373-5710
Mobile [phone]
From: Belnick, Tom [mailto:[e-mail]]
Sent: Friday, January 22, 2010 5:56 PM
To: Lewis, Ron
Cc: Williams, Melanie; Chernikov, Sergei
Subject: Temperature Impairment
Ron- you called last week about a potential temperature impairment of the receiving waterbody (South Fork Catawba
River) near the Allen Steam Station (NC0004979), Outfall 001. 1 know Duke has a 316(a) thermal variance, but I'm not
aware of any defined mixing zone. Thus, if ambient waters exceed the state WQS, then an impaired listing is not
surprising (we have listed waters as impaired for chloride discharged from pickle facilities that have a chloride variance;
the variance protects them from not being able to comply with the chloride WQS, but does not stop the waterbody from
being listed as impaired. Not sure if I have all the specifics, but if this is the case, you might want to stay in touch with
Melanie regarding any future listing, since this process is outside of the NPDES realm.
Tom Belnick
Supervisor, NPDES West Program
NC DENR/Division of Water Quality
1617 Mail Service Center, Raleigh, NC 27699-1617
[phone]; fax [phone]
E-mail correspondence to and from this address may be subject to the North Carolina Public Records Law and may be
disclosed to third parties.

J,Belnick, Tom
From: Lewis, Ron [[e-mail]]
Sent: Wednesday, February 03, 2010 9:04 PM
To: Belnick, Tom
Cc: Williams, Melanie; Chernikov, Sergei
Subject: RE: Temperature Impairment
Attachments: Allen 316a demo.pdf
Tom,
Please see pages 27 and 31 in the attached Allen Steam Station 316(a) demonstration that references the mixing zone
that was originally assigned per the NPDES permit. However, the demonstration supported that a variance of the
thermal water quality standards be granted because confining heat dissipation to the assigned mixing zone would
essentially be impossible. If further documentation is needed to address this issue, I will need to start searching the
archived files.
Thanks,
Ron Lewis
Duke Energy
Mail Code: EC13K
526 S. Church Street
Charlotte, NC 28202
Office 980-373-5710
Mobile [phone]
From: Belnick, Tom [mailto:[e-mail]]
Sent: Friday, January 22, 2010 5:56 PM
To: Lewis, Ron
Cc: Williams, Melanie; Chernikov, Sergei
Subject: Temperature Impairment
Ron- you called last week about a potential temperature impairment of the receiving waterbody (South Fork Catawba
River) near the Allen Steam Station (NC0004979), Outfall 001. 1 know Duke has a 316(a) thermal variance, but I'm not
aware of any defined mixing zone. Thus, if ambient waters exceed the state WQS, then an impaired listing is not
surprising (we have listed waters as impaired for chloride discharged from pickle facilities that have a chloride variance;
the variance protects them from not being able to comply with the chloride WQS, but does not stop the waterbody from
being listed as impaired. Not sure if I have all the specifics, but if this is the case, you might want to stay in touch with
Melanie regarding any future listing, since this process is outside of the NPDES realm.
Tom Belnick
Supervisor, NPDES West Program
NC DENR/Division of Water Quality
1617 Mail Service Center, Raleigh, NC 27699-1617
[phone]; fax [phone]
E-mail correspondence to and from this address may be subject to the North Carolina Public Records Law and may be
disclosed to third parties.

1 0
PLANT ALLEN to 1q7q)
AND
UNITS 1, 2, 3, 4, A 5
316(a) DEMONSTRATION 1
DUKE POWER COMPANY
TABLE OF CONTENTS
CHAPTER PAGES
I. SUMMARY, CONCLUSIONS, AND RECOMMENDATION
SUMMARY 1
CONCLUSIONS 1
RECOMMENDATION 2
II. INTRODUCTION
LEGAL BACKGROUND 3
LOCATION AND PHYSICAL DESCRIPTION 4
ANNUAL TEMPERATURE REGIME 8
III. PLANT OPERATING DATA
UNIT INFORMATION 10
INTAKE 10
DISCHARGE 11
IV. ENVIRONMENTAL DATA
PHYSICAL DESCRIPTION 15
FIELD DATA 15
MATHEMATICAL MODEL 20
RESULTS OF MODELING 21
ASSIGNED MIXING ZONE 27
WATER QUALITY 31
V. BIOLOGICAL DATA
SOURCE BODY OF WATER - CATAWBA RIVER ARM - LAKE WYLIE
Phytoplankton Community 36
Zooplankton Community 37
RECEIVING BODY OF WATER - SOUTH FORK CATAWBA RIVER ARM -
LAKE WYLIE
Vascular Plants and Macroalgae 38
Phytoplankton Community 38
Benthic Macroinvertebrates 39
Fish 41
LIST OF ABBREVIATIONS 48
REFERENCES 49

IST OF FIGUR
FI GURE
PAGE
1.
Regional Site Location
5
2.
Map of Lake Wylie
6
3.
Lake Wylie Area and Volume
Curves
7
4.
Sampling Locations (Fro
Weiss Study Reference 5)
16
5.
Isotherms, in °C, for Sauth
Fork Catawba River
(From Reference 5)
I
17
6.
Isotherms, in °C, for Lake
Wylie - February, April,
-
June 1973 (From Referen
a 5)
18
7.
Isotherms, in °C, for L
ke Wylie - August, October,
December 1973 (From Ref rence 5)
19
8.
Winter Plume - Predicted
Monthly Average
23
9.
Summer Plume - Predicte
Monthly Average "
24
10.
(a), (b) Topographic M
p of Lake Wylie
25,26
11.
Winter Plume - Predicted
Monthly.Average at Ten Foot Drawdown
29
12.
Summer Plume - Predicted
Monthly Average at.Ten Foot Drawdown
30
13.
Schematic Representation
of State of North Carolina
Assigned Heat Dissipation
Zone for Plant Allen
32
14.
Sampling Locations for
Benthic Invertebrates, Periphyton, Phyto -
plankton, Zooplankton,
and Water Quality (From Reference 3)
34
15.
Fish Sampling Location
(From Reference 3)
44

LIST OF TABLES
TABLE
PAGE
1. Recent Plant Allen Monthly Average Inlet Temperature,
Condenser Delta T and Average Outlet Temperature
Compilations 12
2. Plant Allen Monthly Average Thermal Plume Data - Predicted 22
3. Plant Allen Monthly Average Thermal Plume Data for
560.0' Lake Elevation (10 -foot drawdown) - Predicted 28
4. Common and Scientific Names of Fishes Collected
from Lake Wylie, North and South Carolina 42

SUMMARY, CON
SUMMARY
CHAPTER I
;IONS, and RECOMMENDATION
This document summarizes Duke Power Company's 316(a) demonstration for Plant
Allen located on Lake Wylie nea Charlotte, North Carolina. It presents re-
sults of extensive physical, chemical, and biological studies designed to
evaluate the influence of the o eration of Plant Allen upon the aquatic en-
vironment of Lake Wylie. The p incipal sources of information for this
document are reports based on research projects conducted by Duke Power
Company, the University of North Carolina at Chapel Hill, Industrial Bio -Test
Laboratories, and the North Carolina Wildlife Resources Commission.
CONCLUSIONS
The major conclusion of this do'ument is that the heated discharge from Plant
Allen is such that the protection and propagation of a balanced indigenous
aquatic community in and on Lakl Wylie is assured. This major conclusion is
supported by the following:
1. The sport fisheries resourdes of Lake Wylie have not been adversely
affected by the thermal of luent of Plant Allen even though summertime
monthly average discharge emperatures as high as 101.6°F (38.7'C)�1have
been recorded.
2. Water temperatures and oxyen-concentrations beneath the Plant Allen thermal
plume were always sufficie t to support fish life and a substantial zone
of unrestricted fish passa�e was always present.
3. Fish body temperature stud es indicated that fish utilized both the heated
and unheated portions of t e Allen thermal discharge even when temperatures
exceeded 95°F (350C).
4. A large number of threadfishad, an extremely important forage fish,
survive the naturally occurring cold winter temperatures of Lake Wylie
because of the heated disc�arge from Allen.
*See page 48 for a list of abbreviations.

5. Physical, chemical and biological effects attributable to the thermal
effluent from Plant Allen are limited to the vicinity of the discharge
area which is a very small percentage of the total acreage of Lake Wylie.
6. The operation of Plant Allen has a minimal overall impact upon the com-
position, diversity, standing crop and reproduction of phytoplankton,
zooplankton and macroinvertebrates (bottom dwelling organisms) in Lake
Wylie.
7. No rare or endangered species of fish or macroinvertebrates are known to
occur in Lake Wylie.
8. Measurable in -lake effects of the Allen thermal effluent on the viability
of phytoplankton and zooplankton populations are limited to the immediate
discharge area and are not statistically separable from naturally occur-
ring variations in plankton populations.
9. Laboratory bioassays coupled with past and present field observations
show that Lake Wylie waters are not conducive to an overabundant growth
of nuisance blue-green algae.
10. The discharge of cooling water from Plant Allen improves the chemical and
bacteriological quality of the receiving waters by diverting higher
quality Catawba River Arm waters into the lower quality South Fork
Catawba River Arm.
Q_��)limitations
Plant Allen is eligible for alternative, less stringent, thermal effluent
under §316(a). This document demonstrates that such alterna-
tive limitations are warranted.
RECOMMENDATION
The thermal effluent limitations imposed in National Pollutant Discharge
Elimination System Permit No. NC0004979 are requested to be modified to con-
form to the present and anticipated operating parameters of Plant Allen as
described in Chapter IV of this document.
2

i
CHAPTER II
INTRODUCTION
LEGAL BACKGROUND
Under the 1972 Amendments to th� Federal Water Pollution Control Act (the
Act) operators of steam electri power generating units must comply with
applicable technology based eff�luent limitations promulgated by the Ad-
ministrator of Environmental' Pr tection Agency. These limitations, Effluent
Guidelines and Standards, are p�blished at 40 C.F.R. Part 423. In addition,
compliance with effluent limita ions calculated to achieve water quality
standards is required under Sec ion 301(b) (1) (C) of the Act. With respect
to the discharge of heat, however, an exemption from any of these limitations
is available if the operator can make a successful demonstration under
Section 316(a) of the Act.
There are five units in operation at Plant Allen, all of which were placed
in commercial operation prior to January 1, 1970. They are thus 'bid" units
as defined in the Effluent Gui elines and Standards and exempt from the "no
discharge of heat" limitations. Thus, the Effluent Guidelines and Standards
impose no restrictions on discharge of heat from Allen Units 1-5.
According to water quality statjdards for the state of North Carolina, however,
the temperature of receiving waters cannot exceed 90°F(32.2°) and cannot exceed
5°F(2.8°C) above natural tempeIatures beyond the boundary of an assigned mixing
zone. Under the state of Sout Carolina water quality standards, the temperature
of receiving waters cannot exc ed 90°F(32.2°C) and cannot exceed 3°F(1.7°'C) above
natural temperatures beyond th boundary of an assigned mixing zone. A mixing
zone for Plant Allen has been ssigned by the state of North Carolina; however,
due to the nature of the flow attern of the heated water discharge, the
thermal plume from Plant Allen cannot be so confine d. Accordingly, Duke Power
Company has requested that alt rnative, less stringent thermal effluent limita-
tions be imposed under Section 316(a) for the heated water discharge from all
units at Plant Allen.
The following narrative is a brief summary of extensive environmental studies
3

of the physical, chemical and biological effects resulting from the operation
of Plant Allen. This narrative summarizes Duke Power Company's demonstration
that the impact of the heated water discharge from Plant Allen is so insig-
nificant that its continuation "will assure the protection and propagation of
a balanced, indigenous population of shellfish, fish and wildlife" (Reference 1)
in and on Lake Wylie.
IO
The general format of this narrative follows the "Basic Guide to the Design'
f 316 Demonstrations" of Region IV, EPA.
LOCATION AND PHYSICAL DESCRIPTION
Plant Allen is a 1155 MW fossil fired station located on Lake Wylie near
Charlotte, -North Carolina (Figures 1,2). The lake was created in 1904 by the
Southern Company with the construction of a dam on the Catawba River for hydro-
electric power production. Duke Power Company increased the original impound-
ment acreage in 1925 when the dam was raised 50 feet (15.2m) and a new 60 MW
hydroelectric facility was constructed. Lake Wylie, which is located in both
North and South Carolina, extends north from Wylie Dam up the Catawba River
28 miles (45km) to Mountain Island Dam which is another 60 MW hydroelectric
facility. The impoundment extends approximately five miles (8.0 km) up the
South Fork of the Catawba River.
At full pond elevation 569.4 (174m) ms], Lake Wylie has a surface area of
12,455 acres (50 km2), a shoreline of about 325 miles (523 km), a volume
of 281,900 ac -ft (3.46 x 108 m3), and a mean depth of 22.5 ft (6.9m). Its
total watershed is approximately 3020 mi2 (7818 km2) which yields an average
flow of 4100 cfs (116m3/s) through Wylie Dam resulting in a 32 day theoretical
retention time. An area -volume curve for Lake Wylie is presented in Figure 3.
Since 1950 the maximum lake drawdown has been 10.4 ft (3.2m) while the Federal
Power Commission license permits a maximum drawdown of 16 ft.(4.9m) (Reference 2).
Lake Wylie is drawn down approximately five feet
(1.5m) on an annual basis
(Reference 2).
The primary sources of water for Lake Wylie are Mountain Island Lake (Catawba
River), the South Fork Catawba River and other tributary creeks which respective -
4

REGIONAL SITE LOCATION
ouK PLANT ALLEN
5 Figure 1
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22
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2
REGIONAL SITE LOCATION
ouK PLANT ALLEN
5 Figure 1

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Figure 2

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LAKE WYLIE AREA AND VOLUME CURVES
ouM PLANT ALLEN
7 Figure 3
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LAKE WYLIE AREA AND VOLUME CURVES
ouM PLANT ALLEN
7 Figure 3

ly contribute approximately 50%, 25% and 25%'of the total flow. Based on
eight years of records (1963-1970) the average flows through Mountain Island
and Wylie Dam are respectively 2700 cfs (76.5m3/s) and 4400 cfs (12'4.6m3 /s),
while United States Geological Survey streamflow measurements of the South Fork
Catawba Ri yer averaged. _794. cfs (22.5m3/s) from 1942 through 1971 (Reference 3) .
Mountain Island Hydro has an operational range from 2480 (67.9) to 9600 cfs
(271.7m 3/s). Those from Wylie Dam ranged from 2800 (79.2) to 11200 cfs
(317m3/s). Historical flow records for the impoundment are presented in
Reference 3.
ANNUAL TEMPERATURE REGIME
Lake Wylie is characterized by winter water temperatures exceeding 390F(40C),
thermal stratification during the summer, and complete mixing during the
winter,typical of a monomictic lake. Lake Wylie usually reaches its coolest
temperature of about 44°F (7°C) by mid-January. By late March the lake begins
to exhibit natural thermal stratification which becomes well established by
the end of April and is maintained throughout the summer. The fall overturn
usually occurs in September and the lake becomes completely mixed. The in-
tensity of stratification and the occurrence of overturn are influenced by
the operation of Wylie and Mountain Island Hydroelectric Stations operation.
Thermal stratification is usually characterized by temperature differences
from surface to bottom of not more than 9 to 11°F (5-6°C) and overturn may
occur as early as August. This early overturn is due to the low level with-
drawals by the hydroelectric station..
For analysis and discussion purposes, Lake Wylie can be descriptively parti-
tioned into three general areas: (1) South Fork Catawba River Arm, (2)
Catawba River Arm, and (3) Main Body of Lake Wylie. The South Fork area
includes the South Fork Catawba River from the Upper Armstrong Bridge to i_ts
point of confluence with the Catawba River. This region exhibits artifically
induced stratification due to the Allen thermal plume. The bottom waters of
the South Fork flowing beneath the plume are representative of the waters up-
stream which are not influenced by the thermal plume. The Catawba River area
includes the Catawba River Arm from the base of Mountain Island dam to its
point of confluence with the South Fork. This region is riverine in nature

and well -mixed throughout the year. The Main Body of Lake Wylie includes the
area downlake of the confluencelof the two arms to the dam.
0

CHAPTER III
PLANT OPERATING DATA
UNIT INFORMATION
Plant Allen has five independent generating units which have a combined
nameplate capacity of 1155 MW. Units 1 and 2, which began commercial opera-
tion in 1957, are each rated at 165 MW. Units 3, 4, and 5, each rated at
275 MW, became operational in 1959, 1960 and 1961 respectively. _
INTAKE
Condenser cooling water for Plant Allen is drawn from the Catawba River Arm
of Lake Wylie. Each unit has two condenser cooling pumps. Two pumps are
generally used during the summer when the unit is at full load. One pump is
generally used during the winter or when the unit is at reduced load
(Reference 4). Units 1 and 2 share a common cooling water tunnel served by
a total of 4 pumps. Similarly, Units 3 and 4 share a tunnel and -4 pumps.
This design permits the operation of three pumps per tunnel or the equivalent
of 12 -pump operation per unit. This adds an economical range of operating
flexibility. Unit 5 has a separate tunnel and can operate with one or two
pumps.
Condenser cooling water flow rates for each unit for 1, 12, or 2 -pump operation
are as follows:
Unit No.
1 -Pump
1,, -Pumps
2 -Pumps
cfs
'(m3/S)
cfs
(m3/S)
cfs (m3/s) -
1
124
(3.5)
167
(4.7)
205 (5.8)
2
124
(3.5)
167
(4.7)
205• (5.8)
3
185
(5.2)
248
(7.0)
308 (8.7)
4
185
(5.2)
248
(7.0)
308 (8.7)
5
185
(5.2)
308 (8.7)
Total
803
(22.6)
830
(23.4)
1334 (37.8)
Irs

DISCHARGE
The winter and summer condenser cooling water design flows and temperature
rises for Plant Allen are summarized as follows:
Winter Summer
Condenser Cooling 3 —
Water Flow, cfs (m /s) 803 (22.7) 1334 (37.8)
Temperature Rise
dT, OF(OC) 29 (16.1) 18 (10.0)
Presented in Table 1 are recent ionthly average intake temperatures, dis-
charge temperatures'and plant &I's for the period 1968-1974. A comparison
of Table 1 data with the design Jaloes indicates that during the winter
months, plant AT's were well be ow, the design value of 29°F (16.1°C) with
the highest.monthly average &T being 25.8°F (14.3°C). Examination of Table I
reveals that, during the traditional summer months of June, July and August,
the greatest plant &T was 18.9°F (10.5°C). -The highest monthly average
discharge temperature tabulated is 101.6°F (38.7°C) (See Table 1). Historical
monthly average intake temperatures are also presented in Reference 3.

TABLE I
Recent Plant Allen Monthly Average Inlet Temperature,
Condenser Delta --T and Average Outlet Temperature Compilations
12 -
- Average Inlet
Plant
Average Outlet
Temperature
Delta T
Temperature
Month Year
OF(OC)
OF(OC)
OF(OC)
January 1968
43.5(6.4)
23.0(12.8)
66.5(19.2)
February
44.2(6.8)
25.8(14.3)
70.0(21.2)
March
52.2(11.2)
20.8(11.6)
73.0(22.8)
April
- 64.1(17.8)
16.2(9.0)
80.3(26.8)
May
71.1(21.7)
15.1(8.4)
86.2(30.1)
June
78.5(25.8)
15.4(8.6)
93.9(34.4)
July
82.4(28.0)
16.2(9.0)
98.6(37.0)
August
84.5(29.2)
17.1(9.5)
101.6(38,7)
September
78.6(25.9)
16.3(9.1)
94.9(34.9)
October_
71.0(21.7)
14.7(8.2)
85.7(29.8)
November
57.5(14.2)
17.9(9.9)
75.4(24.1)
December
48.6(9.2)
19.3(10.7)
67.9(19.9)
January 1969
44.7(7.1)
22.5(12.5)
67.2(19.6)
February
46.2(7.9)
23.1(12.9)
69.3(20.7)
March
49.2(9.6)
20.3(11.3)
69.5(20.8)
April
61.6(16.4)
17.3(9.6)
78.9(26.1)
May
- 70.4(21.3)
15.7(8.7)
86.1(30.1)
June
77.9(25.5)
13.7(7.6)
91.6(33.1)
July
84.6(29.2)
14.8(8.2)
99.4(37.4)
August
82.4(28.0)
16.0(8.9)
98.4(36.9)
September
78.1(25.6)
13.7(7.6)
91.8(33.2)
October
70.1(21.2
14.2(7.9)
84.3(29.1)
November
57.7(14.3)
22.0(12.2)
79.7(26.5)
December
- 47.9(8.8)
19.3(10.7)
67.2(19.6)
January 1970
43.2(6.2)
23.5(13.1)
66.7(19.3)
February
46.2(7.9)
23.1(12.8)
69.3(20.7)
March
52.9 (1 1 .6)
20-701-5)
73.6(23-1)
April
62.5(16.9)
15.8(8.8)
78.3(25.7)
May
71 .6 (22.0
16.2 (9.0)
87.8(31-0)
June
79.2(26.2)
14.5(8.1)
93.7(34.3)
July
82.4(28.0)
14.5(8.1)
96.9(36.1)
August
86.4(30.2)
14.9(8.3)
101.3(38.5)
September
80.4(26.9)
16.8(9.3)
97.2(36.2)
October
72.1(22.3)
15.5(8.6)
87.6(30.9)
November
59-305.2)
15.8(8-8)
75.1(23-9)
December
51.9(11.1)
17.6(9.8)
69.5(20.8)
12 -

TgBLE I, Continued
Average Inlet Plant Average Outlet
Temperature Delta T Temperature
Month Year °F(OC) °F(°C) °F(°C)
January 1972
50.4(10.2)
18.3(10.2)
68.7(20.4)
January 1971
46.0 (7.8)
23.603-1)
69.6 (20.9)
February
44.2(6.8)
1.8)
16.8(9.3)
61.0(16.1)
March
50.7(10.4)
19.2(10.7)
69.9(21.1)
April
59.3 (15.2)
1.1)
16.0 (8.9)
75.3 (24.1)
May
67.6(19.8)
15.8(8.8)
83.4(28.6)
June
74.5(23.6)
7.4)
16.7(9.3)
91.2(32.9)
,Ju 1 y
81.6W.6)
(8.2)
15.1 (8.4)
96.7(35-9)
August
82.7(28.7)
15.9(8.8)
98.6(37.0)
September
80.3(26.8)
0.6)
14.4(8.0)
94.7(34.8)
October
71.5 (21'.9)
14.1(7-8)
85.6 (29.8)
November
61.0()6.1)
17.3(9.6)
78.3(25.7)
December
52.1 (}
1.2)
16.9 (9.4)
69.o(20.6)
January 1972
50.4(10.2)
18.3(10.2)
68.7(20.4)
February
46.6(8.1)
23.7(13.2)
70.3(21.3)
March
53.2(
1.8)
20.5(11.4)
73.7(23.2)
April
61.6Q6.4)
17.4(9.7)
79.0(26.1)
May
69.9 (
1.1)
14.7 (8.2)
84.6 (29.2)
June
75.4(24.1)
11.8(6.6)
87.2(30.7)
July
81.2 (�
7.4)
14.0(7-8)
95.2(35-1)
August
82.8
(8.2)
15.8 (8.8)
98.6(37-0)
September
79.4(26.4)
15.2(8.4)
94.6(34.8)
October
69.0(1
0.6)
15.4(8.6)
84.4(29.1)
November
59.6(15.3)
19.9(11.1)
79.5(26.4)
December
50.9(10.5)
18.3(10.2),
69.2(20.7)
.January 1973
46.9,8-3)
18.600-3)
65.5 (18.6)
February
45.9 (17.7)
18-500-3)
64.4(18.0)
March
51 .6 (110.9)
2.600-3)
70.2 (2i .2)
April
57.4(114.1)
18.4(10.2)
75.8(24.3)
May
65.9(18.8)
18.5(10.3)
84.4(29.1)
June
76.1124-5)
18.7 (10.4)
94.8 (34.9)
July
82.3127.9)
18.9(10.5)
101.2(38.4)
August
82.9 128.3)
18.7.(10.4)
101.6(38-7)
September
81.1127-3)
18.9(10,5)
100.0(37.8)
October
72.'5122.5)
19.5 (10.8)
89.6 (32.0)
November
60.5
15.8)
19.2(10.7)
79.7(26.5)
December
50.7
10.4)
20.5(11.4)
71.2(21.8)
January 1974
50.1,10-1)
19.3(10.7)
69.5(20.8)
February
49.6(9.8)
19.3(10.7)
68,9(20.5)
March
54.1
12.3)
19.0(10.6)
73.0(22.8)
April
60.1
15.6)
18.7(10.4)
78.7(25.9)
May
69.3
20-7)
20.8(11.6)
89.4(31.9)
13

TABLE I, Continued
14
Average Inlet
Plant
Average Outlet
Temperature
Delta T
Temperature
Month Year
OF(OC)
OF(OC)
0F(0C)
June 1974
77.3(25.2)
17.2(9.6)
94.5(34.7)
July
80.8(27.1)
16.9(9.4)
97.7(36.5)
August
81.5(27.5)
16.3(9.1)
97.8(36.6)
September
76.3 (24.6)
16.7(9-3)
93.1(33-9)
October
66.9(19.4)
19.1(10.6)
86.0(30.0)
November
59-105-1)
17.2(g.6)
76.3 (24.6)
December
47.7(8.7)
17.1(9.5)
64.8(18.2)
14

ENI
PHYSICAL DESCRIPTION
CHAPTER IV
/IRONMENTAL DATA
Plant Allen uses the Catawba River Arm of Lake Wylie as its source of
condenser cooling water and discharges into the South Fork Catawba River
Arm through a 3/4 -mile discharge canal (See Figure 2). The discharge
causes turbulent mixing within the upper layer of the South Fork receiving
waters. This turbulent mixing 'area is approximately 230 acres (0.9 km2).
FIELD DATA
Duke Power Company sponsored two independent, one-year environmental studies
on Lake Wylie spanning 1973 and 1974. The first was directed by Dr. Charles
M. Weiss of the University of North Carolina for the period February 1973
through January 1974 (Reference 5). The second study was conducted by
Industrial Bio -Test Laboratories, Inc. from September 1973 through
August 1974 (Reference 3).
Horizontal and vertical thermal distribution patterns in the South Fork
Catawba River Arm from*Weiss's study (See Figure 4 for sampling locations)
are shown for each month of the period February, 1973 - January 1974 in Figure 5.
Isotherm patterns in Lake Wylie'for the months of February, April, June, August,
October and December 1973, are presented in Figures 6 and 7. The heated dis-
charge enters the South Fork River Arm approximately opposite Station 2.0
(See Figure 4). The maximum surface water temperatures occur at this point
and diminish as the plume floals downlake and, to a limited extent, uplake
approximately 1.5 miles. The lume temperature decreases rapidly toward
natural levels as it moves dow stream toward the confluence with the Catawba
River Arm (Figure 5). Allen's thermal plume enters the main body of Lake Wylie
at Station 78.9 and spreads dolnlake and uptake for comparatively short dis-
tances (Figures 6 and 7). Tem eratures within the plume as it reaches the
confluence of the two arms of he lake are -usually elevated only 2-3°C above
the rest of the lake and a substantial zone of passage is always available
beneath the plume (Reference 5i. Thermal studies conducted by Industrial Bio -
Test (Reference 3) substantiat this plume behavior.
15

Fi gure 4
16

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LU
:560 --�
n
Lu _550 .,
Z � -
}--
Z
530
O
520
}
510
600,
166 4
r
T B.il
7.5
\�-
r 70
7.0
83.1
78.9
�74
�- 18.0
560
o p
550
w c o
�r 540 o p
}-- p 13.0
f1 530
0 0 0
O 520
V o
} 510 70.8
S
500
FEBRUARY 1913
--
o
0 18.0 0 15.0
!74.2
0 0
17.0 0
0 83.1
78.9
APRIL 1973
WYLIE
560 y
0
25.0 c
�..._ " 25.0
550 —_
24.0 o� p o
W
')'� p
Q Sao }- -, - 23.0
0
530 - ).: 0
C) 52.0
78 9
� 74.2
cm 510
y ?C.6
= p
500 68 i
66 4
JUNE 1973
ISOTHERMS,IN 0C,FOR LAKE W YLIE
FEBRUARY,APRIL, JUNE 1973
( FROM REFERENCE 5 )
DUKE} PLANT ALLEN
Figure 6
18

0 ° ---
360 0 0 n 29.0 00
o u o 0 28. 0 0
w 1550 0 0 ° 0 0 0
Y 0 ° 0 0
d 540 0 0
I--- ° o u 0 27.0
v
r -i 330 °
03.1
520 ` 78.9
p 74.2
>- 510 70.8
Z
500 68.1
66.4
WYLIE
ALGUST 1973
360 23.0 0 0 ° 24.0 0
0 0 0 3.0 0
22.0 0
W550
° ° 0
°� 0. ° I
F¢- 540 d ° 0
0 0
O ~ 530 I 83.1
r O 78.9
5 20 74.2
LUJ
S 510 70.8
W
500 66.4 68.1
WYLIE
OCTOBER 1973
III Z.
560 0 0
0 0 0 0 0 0
W 550 ° °
Y o 0 0 0 0
Q 540 11.0
F' 0 0 0 0
H 530 63.1
0
0 0 0 78.9
O
520 74.2
� o
r 510 70.8
Z
0
500 68.1
66.1
WYLIE
DECEMBER 1973
ISOTHERMS,IN °C,FOR LAKE WYLIE
AUGUST,OCTOBER, DECEMBER 1973
( FROM REFERENCE 5 )
C:EPO PLANT ALLEN
Figure 7
19

Y
MATHEMATICAL MODEL
In addition to the actual field data collected on Lake Wylie depicting Allen's
thermal plume, predictive mathematical modeling studies were conducted to
determine the most extreme monthly average thermal plume conditions. As
mentioned earlier in this chapter, Plant Allen discharges through a canal
into the South Fork Catawba River Arm. This heated water discharge eventually
moves downlake to the main body of Lake Wylie. Special drogue, dye and
thermal imagery studies conducted by Duke (1970-1973) have demonstrated that
the flow patterns between the discharge canal and the Lower Armstrong Bridge
were very complex. For this reason, the plume modeling was divided into two
regions: Region ]).canal to the Lower Armstrong Bridge, and Region 2)
downlake of the Lower Armstrong Bridge. As a result of the complex
flows involved, no attempt was made to model isotherms in Region 1. Instead,
a plug flow model with dilution and surface heat loss was used to predict
temperatures at the Lower Armstrong Bridge. The resulting equation for the
temperature excess ( ATLAB ) at Lower Armstrong Bridge is:
AT LAB = AT 0 exp C- HA/ P CvQtil (1)
t D L JJ
s
where G Tois the temperature rise through Allen, Ds the dilution, H the
surface exchange coefficient, A the surface area between the discharge canal
and Lower Armstrong Bridge (approximately 230 acres),Qthe water density, C
the specific heat, and Qo the plant volumetric flow rate. A series of
vertical temperature profiles at 25 stations in the South Fork Catawba River
Arm taken in 1972 and 1973 was used with Equation (1) to determine Ds which
is defined as the ratio of the entrained flow to Qo. The median value obtained
from these measurements was approximately 0.8. A surface exchange coefficient
of 5 BTU/ft 2/°F/Hr was used in the model.
Analysis of Region 2 was accomplished using the surface heat transfer portion
of the transient cooling pond model developed at Massachusetts Institute of
Technology (MIT) by Ryan and Harleman (Reference 6). Validation of the complete
model was accomplished by comparing daily temperature measurements and pre-
dicted distributions, using daily plant flows, a T's and daily meteorology.
20

The hypothesized "extreme" year is a combination of several highly unlikely
model input conditions. The year 1953 was used since it exhibited the most
extreme meteorological conditions based on a 23 -year period of record (1951-
1973) from Charlotte's Douglas Airport. Maximum monthly average intake
temperatures were selected by studying operating logs -for the three years
(in the period 1960-1970) which had the highest summer and winter equilibrium
temperatures, resulting in maxi um summer and winter values of 85°F (29.4°C)
and 52°F (11.]°C) respectively. These conditions existed in August, 1968
and December, 1967. Plant Alle is condenser flows and temperature increases
( oT's) were based on full capacity (1155 MW) operating conditions with one -
pump operation (803 cfs) in the winter and two -pump operation (1334 cfs) in
the summer.
RESULTS OF MODELING
Based on the modified MIT model (Reference 6) the simulated monthly average
thermal plume acreages, shorelines in the elevated temperature region and
their respective percentages of the total lake values for the extreme
summer and winter conditions ale presented in Table 2 (p. 22). The
thermal plume is herein defines{ as 90°F (32°C) or 3°F (1.7°C) AT
excess above background lake temperatures in South Carolina and as 90°F
(32°C) or 5°F (2.8°C)o T in North Carolina. Under extreme winter conditions
2800 ac (11.3 km2) representing 22% of the surface area of Lake Wylie was
simulated to be 30F 0.7%) above ambient lake temperatures, as a result of
Plant Allen. This drops to 1950 ac (7.9 km2) or 16% of the lake surface when
a 5°F (2.8°C) o T is considered
For simulated extreme summer conditions, 1100 ac (4.5 km2), representing 9%
of the total lake area, were f and to be in excess of 90°F (32°C); this area
also represents the 5°F (2.8°C oT plume. The 3°F (1.7°C) AT plume encom-
passes an area of 1850 ac (7.5 km2) or 15% of the lake. Figures 8 and 9 show
the extent and approximate location of the thermal plumes for winter and
summer conditions respectively.
A topographic map of Lake Wyli
le (Figure 10(a) (b)) shows that the shallow areas
21

N
N
TABLE 2. PLANT ALLEN MONTHLY AVERAGE THERMAL PLUME DATA - PREDICTED
Thermal Plume Data
Plant
operating Conditions 90'F (32°C) Isotherm
Reference Extreme Condenser T Loadl Intake Discharge N. C. S. C. Total5 % N. C.3 % S. C.3 `/, Total N. C. S. C. Total % N. C.4 % S. C.4 % Totals
Figure Flow Temp. Temp. Surface Surface Surface Lake Lake Lake Shoreline Shoreline Shoreline Lake Lake Lake
cfs "F `C %• 'F 'C 'F "C Acres Acres Acres Acrea a Acreage Acreage Miles Miles Miles Shoreline Shoreline Shorelin(
Figure 8 Winter 803 29(16.1) 100 52(11.1) 81(27.2) 0 0 0 0 0 0 0 0 0 0 0 0
Figure 9 Summar 1334 18(10) 100 85(29.4) 103(39.4) 670 430 1100 101, 8% 9% 12.5 1.5 14 5% 2% 4%
5'F(2.8`C) Excess 3'F(1.7'C) Excess
ABOVE INTAKE ISOTHERM ABOVE INTAKE ISOTHERM
N. C. Total .7 N. C. % Total N. C. Total % N. C. % Total S. C. Total % S. C. % Total S. C. Total % S. C. % Total
Surface Surface Lake Lake Shoreline Shoreline Lake Lake Surface Surface Lake Lake Shoreline Shoreline Lake Lake
Acres Acres Acreage Acreage Miles Miles Shoreline Shoreline Acres Acres Acreage Acreage Miles Miles Shoreline Shoreline
Figure 8 Winter 1100 1950 16% 16A 17.5 25 8'/,-, 8`„ 1100 2800 20% 2T'/, 9.5 34 10% 101/1
Figure 9 Sumner 670 1100 10% 9% 12.5 14 5`! 4% 720 1850 13% 15% 6 20.5 6'/, 6%
IPLANT full load operating capacity = 1155 MW
2Based on maximum monthly average intake temperatures selected from period 1960-1970; winter -December, 1967; summer -August, 1968.
313ased on full pond lake elevation at 569.4` msl (12,455 acres); lake surface acreage in N. C. and S. C. are respectively 6,975 and 5,480 acres.
4Based on total shoreline mileage of 327 miles; 232 miles in N. C. and 95 miles in S. C.
5Total refers to sum of affected areas in both North and South Carolina.

uth
Carotin- o �� •.
n
0
0
S
a
:R ARMSTRONG
BRIDGE
PLANT
ALLEN
f o INTAKE
° 60
LOWER
ARMSTRONG DISCHARGE
BRIDGE CANAL
(81°F/27.20C)
STATION
O
LAKE WYLI E
WATER SURFACE (c) EL. 570
WINTER PLUME—PREDICTED [IONTHLY AVERAGE
dune PLANT ALLEN
Figure 8
23
5
tr'
I 2
SCALE IN 411LE5
LEGEND
®3°F
(EXCESS ABOVE
2°
INTAKE TENT 5F/11.1°C)
INTAKE
r�
CEM ABOVE
INTAKE TEMP. 52°F/II.I°C)
STATION
O
LAKE WYLI E
WATER SURFACE (c) EL. 570
WINTER PLUME—PREDICTED [IONTHLY AVERAGE
dune PLANT ALLEN
Figure 8
23

f)
D
E
4
UPPER ARMSTRONG
BRIDGE
?� APLANT
V�vl ALLEN
"41,
INTAKE
\ BRIDGE v \` CANAL qGE
CANAL
Na -Ca rfh (103°F/39.4°C)
r o I i n a
5
SCALE IN MILES
LEGEND
3° F (EXCESS ABOVE
ti INTAKE TEMP. 85°F4°C)
C`$+
F & 5 (EXCESS EXCESS ABOVE
7 K
NNrr�� f� INTAKE TEMP. B5°F/29.4°C) I
Y\Y�\LIIE STATION ,
\V1
LAKE WYLIE
NATER SURFACE (a7 EL.570
SUMMER PLUME -PREDICTED MONTHLY AVERAGE
oua PLANT ALLEN
Figure 9
24

3nia
Q J
U z
D Q
0 U
C
TOPOGRAPHIC MAP OF LAKE WYLIE
oua PLANT ALLEN
25 � Figure 10 (a)
crW
N
LL w
p
W W
y N p
F N _
W
Z
—
W
r
O
LjQ
N
z
ZQo -
K
aL>U
T -
0)U
TOPOGRAPHIC MAP OF LAKE WYLIE
oua PLANT ALLEN
25 � Figure 10 (a)

TOPOGRAPHIC MAP OF LAKE WYLIE
DUKE POWER PLAINT ALLEN
26 Figure 10 (b)

ef f,
oPo1�
are adjacent to the shoreline. Therefore, the percentage of shallow areas
in the elevated temperature region is approximately equal to the percentage
of shoreline in the elevated to perature region. Approximately 34 mi (55 km)
or 10% of the total lake shoreline is affected by the 3°F (1.7°C) AT for the
extreme conditions. For a 5°F 2.8°C) AT during the winter 25 mi (40 km) or
8% of the shoreline is affected 11l During the extreme summer simulation 14 mi
(23 km) or 4% of the Lake Wylie shoreline is affected by the 90°F (32°C)
thermal plume. Since an 85°F (29.4°C) intake temperature is used the shoreline
in the 5°F (2.8°C) AT plume is the same as for the 90°F (32°C) thermal plume.
Six percent of the shoreline is affected by the 3°F (1.7°C) AT thermal plume.
The Plant Allen intake temperature (and thus the discharge temperature)
is not appreciably affected by I drawdown condition in Lake Wylie. The
area required for the 90°F,'5°F AT and 3°F AT heat dissipation zones re-
mains the same for both drawdown and full pond lake surface elevations.
Figures 11 and 12 and Table 3 present thermal plume data assuming a 10 -
foot drawdown for Lake Wylie. This plume data analysis was based on the
same meteorological and plant operating condition as for the full pond
analysis. Under drawdown condil tions the heat dissipation zones extend
further down the lake. Although the total plume area remains constant,
I
there'is a change in the relatilve distribution of the plume in North and
South Carolina. Due to lake bottom topography, North Carolina has an
increase and South Carolina has a decrease in plume area.
ASSIGNED MIXING ZONE
The State of North Carolina assigned a heat dissipation zone (mixing zone)
for North Carolina waters for Pant Allen. This zone encompasses that portion
of the thermal plume where surface temperatures are permitted to exteed 5°F
(2.8°C) AT above natural temp rature and/or 90°F (32°C). It is delineated
as being "the eastern two-thir s of the South Fork Catawba River (as measured
from the eastern shoreline) lying between upper Armstrong Bridge (State
Road No. 2519 bridge), and the Catawba River; and the western two-thrids of
the Catawba River (as measured from the western shoreline of the river)
extending from the Allen Steam Station intake structure to the South Fork
Catawba River" (From NPDES Permit No. NC0004979). This mixing zone is
27

Reference Extreme
Figure
Figure 11 Winter
Figure 12 Summer
N
rye
Figure 11 Winter
Figure 12 Summer
Table 3. Plant Allen Monthly Average Thermal Plume Data for 560.0'
Lake Elevation (10 -foot drawdown) - Predicted
Plant Thermal Plume Data
Operating Conditions 90'F (32%) Isotherm
Condenser AT Loadl Intake Discharge N. C. S. C. Total3 Total3 N. C. S. C. Total3
Flow Temp. Temp. Surface Surface Surface Lake Sh•,re- Shore- Shoreline
line line
cfs 'F('C) '%. 'F('C) 'F('C) Acres Acres Acres Acreage Miles Miles Miles
803
1334
N. C.
Surface
29(16.1) 100
2800
52(11.1)
81(27.2)
0
0 0
0
0 0
0
18(10) 100
85(29.4)
103(39.4)
821
279 lion
12
16 3
19
5'F(2.8'C) Excess
3'F(1.7'C) Excess
ABOVE INTAKE ISOTHERM
ABOVE INTAKE ISOTHERM
Tota13 '% Tota13
N. C.
Total3
S. C.
Total3
% Tota13 S. C.
Tota13
Surface Lake
Shore-
Shoreline
Surface
Surface
Lake Shore-
Shoreline
line
line
Acres Acres Acreage Miles Miles Acres Acres Acreage Miles Miles
1264 1950 21 24 33
821 1100 12 16 19
994
2800
30
14.5 48
630
1850
20
8 31
PLANT full load operating capacity = 1155 MW
2Based on maximum monthly average intake temperatures selected from period 1960-1970; winter -December, 1967; summer -August, 1968.
3Total refers to sum of affected areas in both North and South Carolina.

!-es
L4 S. 79 ono
o
"-•'LPKR ARMSTRONG
•;I BRIDGE
PLANT
ALLEN
INTAKE
p0 LOWER. ..
ARM$TRON{l.•, ••;•
`B.!RIDGE.::.
t
DISCHARGE
CANAL
SOolhh Carolinna
(81°F/27,2°C)
t„ ... S.C. 49
Got
J
O' I 2
/ SOLE IN A11 L[5
LEGEND
•~'I�:'- ' +-
30F (EXCESS ABOVE
•' �'
:.PJJJJ/,]
Y�l� INTAKE TEMP, 52°F/II.10C)
5°F(EXCESS ABOVE
INTAKE TEMP. 52°F/11.10C)
'
,WYLIE STATION
LAKE WYLIE
WATER SURFACE (a) EL
560
WINTER PLUME—(PREDICTED
MONTHLY
AVERAGE AT T
FOOT DRAWDOWN
ouK PLANT ALLEN
Figure Ill

j
30

Y
shown schematically in Figure 13;.
Compliance with the State assigr'ed heat dissipation zone would be impossible'
without the construction of a p`1ysical barrier to restrict the thermal plume
to the assigned zone. Studies of cooling pond mechanics by various authors
have demonstrated that density differences between the heated plume and the
lake surface temperature set up "density currents". Ryan and Harleman
(Reference 6) provide a theoretical basis for the existence of density flows
and discuss confirming laboratoly and field results. These currents are the
primary mechanism by which the surface plume, in the process of cooling, is
transported into remote portions of a cooling lake allowing effective use of
the lake surface areas for cooling. The plume is buoyant and tends to spread
uniformly over the water surface. However, due to river flows, operation
of Mountain Island and Wylie Hydro Stations, high winds, rainfall and other
changing meteorological conditions, the thermal plume meanders over the water
body.
The maximum monthly average heat dissipation zone required by Plant Allen is
2200 acres (8.9 km2). This is 1 computed projection based on extreme hydro-
logical and meteorological conditions. An evaluation of Duke Power Company _
field data and extensive studies conducted by Industrial Bio -Test Laboratories,
Inc. (Reference 3) and by Weiss (Reference 5) confirm this projection. The
heat dissipation zone would be contiguous with the end of the Allen discharge
canal and encompass waters in both North and South Carolina. Of the total
2200 acres (8.9 km2), 1100 acres (4.5 km2) would be in North Carolina, based
on the 90°F (32°C) or 5°F (2.8°C) AT water quality standard. The remaining
1100 acres (4.5 km2) would be in South Carolina assuming a 90°F (32°C)
or 3°F 91.7°C) pT standard (S e Table 2 and Figures 8 and 9). The geo-
graphical boundaries of the heft dissipation zone would vary with the meandering
of the thermal plume. It shoud be noted that it is winter time operation of
Plant Allen which determines tie maximum size of the heat dissipation zone.
WATER QUALITY
A recent study of Lake Wylie water quality was conducted by Industrial Bio -
Test for Duke'Power Company from September 1973 to August 1974 (Reference 3)
31

NORTH CAROLINA
SOUTH CAROLINA
0
Nommomm
SCALE IN MILES
I
DISCHARG
CANAL
MIXING
ZONE
LOWER
ARMSTRONG
�, BRIDGE
SCHUTATIC REPRESENTATION OF STATE
OF NORTH CAROLINA ASSIGNED HEAT
DISSIPATION ZONE FOR PLANT ALLEN
oua PLANT ALLEN
Figure 13
32

(See Figure 14 for sampling locations). Weekly profiles of temperature,
oxygen, conductivity, pH and tratismissivity and monthly chemical and bacte-
riological analyses were made at 20 locations throughout the lake during the
year. These studies indicated that the study area was comprised of three
distinct water systems: the Cat wba River Arm, typical of a well mixed
river; the South Fork Catawba Riier Arm, an artifically stratified system
resulting from the flow of ambient South Fork water beneath the Plant Alien
thermal effluent; and the Main Body of Lake Wylie.
Concentrations of major chemical constituents were typical of a drainage
system originating in an area underlain by igneous and metamorphic bedrock.
The highest values of most parameters occurred in ambient South Fork Arm
waters, unaffected by the Allen discharge. These values probably reflected
the upstream discharges of industrial and municipal wastes (Reference 3).
Associated with industrial and municipal waste discharges are decreased
oxygen concentrations ('oxygen sags") some distance below the point of dis-
charge. These oxygen sags, if they develop, can be accentuated by increased
temperatures due to thermal effl ents. An analysis of theoretical considera-
tions and existing data (Reference 3) revealed that the Plant Allen thermal
discharge has little or no measurable effect on the oxygen concentration
(organic loading) of the South Fork Arm of Lake Wylie (Reference 7),
Catawba River waters had a pred
main body of Lake Wylie. Howev
of ambient South Fork water wer
as far as 10 miles downstream f
Catawba Rivers (Reference 3).
minant effect on water quality within the
r, chemical and bacteriological parameters
sometimes measured in Lake Wylie bottom water
om the confluence of the South Fork and
During the late spring and summ r months of the study period, pH values in
Lake Wylie exceed state water quality standards. These high pH values
resulted from naturally occurri g photosynthetic activity in Lake Wylie.
Nitrogen and phosphorus concent ations were generally highest in natural
South Fork Arm waters. Overall) the Plant Allen discharge exerted a positive
effect on the chemical and bacteriological quality of the South Fork Catawba
33

SAMPLING LOCATIONS FOR BENTHIC INVERTEBRATES,
PERIPHYTON, PHYTOPLANKTON, ZOOPLANKTON AND
WATER QUALITY (FROM REFERENCE 3)
PLANT
Figure 14
34

River Arm waters by diverting hi
the comparatively lower quality
]her quality Catawba River Arm waters into
iouth Fork water.
35

CHAPTER V
BIOLOGICAL DATA
SOURCE BODY OF WATER - CATAWBA RIVER ARM - LAKE WYLIE
Phytoplankton Community
The phytoplankton community of the Catawba River Arm of Lake Wylie in the
vicinity of Plant Allen was studied from February 1973 to January 1974, by
Weiss et al. (Reference 5) (See Figure 4 for sampling locations) and from
September 1973 to August 1974 by Industrial Bio -Test Laboratories (Reference
3) (See Figure 14 for sampling locations). Monthly quantitative phyto -
plankton samples were taken by both researchers in Lake Wylie including the
Catawba River Arm and the South Fork Catawba River Arm. The naturally occur-
ring seasonal population patterns of phytoplankters were comparable for
both studies. Data from these studies are used in the following discussion.
The upstream impoundments of the Catawba River System were probably the origin
of the majority of phytoplankton species in the Catawba River Arm and in Lake
Wylie (Reference 3). The South Fork did contribute a small but distinctive
riverine type flora (Reference 3). Results of seasonal Phytoplankton population
studies indicated that lowest densities of all algal divisions occurred in
the winter. Maximum densities varied seasonally for each algal division. The
diatoms (Bacillariophyta) and the green algae-(Chlorophyta) dominated the phyto -
plankton in Lake Wylie. Diatoms reached their greatest abundance in May and
the principal genera included Melosira, Stephanodiscus and Cyclotella. Maximum
densities for the green algae occurred in June. The most abundant green algal
taxa were Chiamydomonas, Nannochloris, Mesostiqma and_Scenedesmus (Reference 3). _
The blue-green algae (Cyanophyta) were a minor constituent of the total phyto -
plankton populations. The most quantitatively important blue-green algal taxa
were the colonial genera Aphanocapsa, Aphanothece, Merismopedia and Microcystis
and the filamentous Anabaena and Oscillatoria.
36

The dinoflagellates (Pyrrhophyte
(Euglenophyta), cryptomonads (Cr
dophyta) were present in relativ
portion of biomass compared to t
Zooplankton Community
The zooplankton community of La
sampled monthly from February 1
(See Figure 4 for sampling loca
August 1974 by Industrial Bio -T
locations).
j, yellow-brown algae (Chrysophyta), euglenoids
(ptophyta) and the chioromonads (Chloromona-
:ly low numbers and accounted for a negligible
ie diatoms and green algae (Reference 3).
e Wylie in the vicinity of Plant Alien was
73 to January 1974 by Weiss et al. (Reference 5)
ions) and monthly from September 1973 to
st (Reference 3) (See Figure 14 for sampling
The rotifers were the most numerically abundant constituents of the Lake
Wylie zooplankton community (References 5 and 3). The rotifer population
densities were generally greater during April through August with highest
populations occurring in April and May. Dominant rotifers, those genera com-
prising 10% or more of the total zooplankton, included Asplanchna, Brachionus,
Conochiloides, Conochilus, Keratella, Polyarthra and Synchaeta. Keratella and
Polyarthra, the most common genlLra, were present throughout the year and attaire d
greatest population densities ih May. Brachionus was a summer form and was
dominant only in the South Fork. Conochiloides and Conochilus were dominant
summer forms. Asplanchna was the dominant genus only in the spring. Synchaeta
was the only genus present throlughout the year which had two density maxima:
one in January and one in May.
The most abundant cladocerans
The various cladoceran genera
but they comprised only an ave
(Reference 3). Bosmina was pr
pulses in spring and fall (Ref
attained maximum abundance in
ere Bosmina and Daphnia (References 5 and 3).
xhibited seasonal differences in abundance,
age of 10% of the total zooplankton population
sent all year long and exhibited population
rence 3). Daphnia was common in February and
ay. The greatest adult copepod population
densities were present during the fall and the spring. The rotifer, cladoceran
and copepod populations exhibi ed fluctuations in densities typical of reservoirs
and lakes of the Piedmont region (Reference 5).
37

RECEIVING BODY OF WATER - SOUTH FORK CATAWBA RIVER ARM - LAKE WYLIE
Vascular Plants and Macroalgae
Field observations of shallow near -shore areas of the entire reservoir
(including the elevated temperature region) confirmed that rooted aquatic
vegetation (vascular plants) and algae attached to submerged surfaces
(periphyton) and macroalgae constitute an insignificant portion of the lake's
total primary production (See Figure .14 for sampling locations). The near ab-
sence of both rooted aquatic vegetation periphyton is attributable to the
combined effects of changes in lake level caused by hydroelectric operation
and reduced light penetration caused by naturally occurring high turbidity
levels (Reference 3) .
Phytoplankton Community
Thermal discharges from Plant Allen into the South Fork Catawba River Arm
spread uplake as well as downlake and diluted the nutrient -rich waters of
the South Fork (Reference 5). The South Fork Catawba River Arm contained a
small but distinctive phytoplankton community consisting mainly of pennate
diatoms, non -motile green algae and euglenoids (Reference 3). The operation
of Plant Allen caused a thermal stratification in the discharge area and a
subsequent phytoplankton stratification. Phytoplankton taxa characteristic
of the Catawba River Arm were more prevalent in the heated surface water while
phytoplankton taxa typical of South Fork Catawba River Arm were more frequently
found in the cooler, deeper water. At the interface of the plume and ambient
South Fork waters, a highly variable degree of mixing between the two phyto -
plankton assemblages was observed (Reference 3). There was no evidence that
the thermal discharge from Plant Allen had been or is causing any shift in
the phytoplankton flora of South Fork Arm to more heat tolerant species
(Reference 5).
Operation of Plant Allen did not cause a reduction in the species diversity
of zooplankton. The discharge of condenser cooling water from Plant Allen
had no measurable overall influence on zooplankton populations in Lake
Wylie (Reference 3).
M

Bioassay results indicated that
conducive to the overabundant g
(Reference 3). Furthermore, th
Plant Allen on the ability of t
algal growth as a function of n
that the operation of Plant All
qualitative variation of plankt
Arm and South Fork Catawba Rive
Benthic Macroinvertebrates
he Lake Wylie study area waters were not
wth of potential nuisance blue-green algae
e results did not indicate any influence of
Lake Wylie study area waters to support
rient content (Reference 3). It is concluded
had no influence on the quantitative and/or
below the confluence of the Catawba River
Arm.
A quantitative survey of the benthos (bottom dwelling invertebrates) of Lake
Wylie was conducted by Industrial Bio -Test Laboratories for Duke Power Company
from October 1973 through August 1974 (Reference 3) and by Lenat and Weiss
in 1972 (Reference 8). Samples Iwere taken every two months from October to
April, and every month thereafter through the spring and summer (Reference 3)
(See Figure 14 for sampling locations). No known rare or endangered species
were found in Lake Wylie (Referinces 9 and 10).
A total of 121 taxa were reportbd in benthos collected from Lake Wylie during
the 1973-74 studies (Reference �). Total numerical densities averaged ap-
proximately 1500 organisms per 2 throughout the study area. No consistent
pattern of change with season w,s apparent at any station; differences which
did occur were associated with ;changes in sediment type.
Benthic biomass was dominated
first appeared in Lake Wylie a
those from the South Fork Arm
were immatures. Although the
location and time, that of the
the study.
Approximately 30% by number of
the family Chironomidae (midge
most diverse group collected.
sediment in shallow water, les!
y the Asiatic clam (Corbicula manilensis) which
out 1968 (Reference 3). With the exception of
f the lake most (sometimes 99%) of the Corbicula
ensity of the immatures fluctuated widely with
adults remained relatively constant throughout
the benthos in Lake Wylie are insect larvae of
flies). The 40 taxa represented also made it the
Chironomids were most common in fine grained
so in rocky areas and, in deeper water, they
39

tended to be replaced by larvae of the phantom midge (Chaoborus punctipennis).
Both chironomids and C. punctipennis are important as fish food.
Equally abundant and almost as diverse as the Chironomids were the oligochaetes
(aquatic worms),.which comprised 50% by number of the total benthos collected
during the study (Reference 3). They varied markedly, however, in both density
and species composition among stations and with time.
Numerous other taxa of macroinvertebrates were collected. These included the
larvae of a variety of insect groups (mayflies, dragonflies, caddisflies and
beetles, among others), molluscs, leeches, a fresh water sponge and a variety
of minor invertebrate groups. They did not constitute more than 10% by number
of the total benthos for the study period. All species found are common to
fresh water lakes and rivers.
Only two areas sampled for benthos exhibited an influence of the Allen thermal
discharge. One, in the shallow areas near shore at the mouth of the discharge
cove, averaging 5.8°C (10.4°F) higher than the intake temperature; the other,
in the shallow areas near shore one mile downlake of the discharge, averaging
5.6°C (10.1°F) higher than the intake. In one study the effects of the thermal
discharge on the benthos revealed that the number of organisms whose population
density increased was approximately equal to the number of organisms whose
population decreased (Reference 8). In this study it was also reported that in
the discharge area "overall productivity was depressed, but this effect was
limited to the discharge canal and the immediate area of discharge into the
lake" (Reference 8). In a more recent study (Reference 3) the diversity index,
a relative measure of environmental stress, was consistently lower in the Allen
discharge area than in other areas of Lake Wylie. However, the overall con-
clusions of the report are that "the thermal discharge from the Allen Station
did not have an overall influence on benthic macroinvertebrates in the Lake
Wylie reservoir" and that "no consistent seasonal differences in benthic popu-
lations were measured at sampling locations within areas influenced by the
thermal discharge of the Allen Station versus locations which were not" (Reference 3).
40

Fi sh
r
A list of fish species collected by the North Carolina Wildlife Resources
Commission in 1965 and by Industrial Bio -Test Laboratories in 1973-74 are
presented in Table 4. Based on these studies 45 species representing 10
families have been recorded from Lake Wylie (References 3 and 11). Numbers
of species reported for the two studies are similar (Table 4) indicating no
major shift in species composition had. occurred during this time period. No
rare or endangered fish species are known to occur in Lake Wylie.
Results of the year-long fish stbdy of Lake Wylie conducted by Industrial
Bio -Test showed that the total catches of fish (excluding threadfin shad) by
gill netting and electroshocking were greater in the discharge cove than in
any other location sampled (Reference 3) (See Figure 15 for sampling locations).
Even though monthly average discharge temperatures reached 100.0°F (37.8°C)
during the 1973-1974 study period, the number of fish species collected from
the elevated temperature region, except the discharge canal, was equal to or
greater than that collected from outside the heat—affected area (Reference 3)..
It is generally hypothesized thalt a shift in fish composition from sport to
either forage or rough fish or both is usually associated with increased thermal
loading. This was not observed lin Lake Wylie where gill net catch rates of
sport fish during all seasons were generally greater in the Allen discharge
cove than in all other location sampled (Reference 3). These findings show
that the Allen discharge temperatures outside the discharge canal did not limit
fish abundance or diversity.
Fish distribution in Lake Wylie was dependent on a variety of factors including
the suitability of habitat. This seemed to be especially true for sunfishes
which were collected in greates numbers from downlake locations. Redbreast
sunfish and pumpkinseeds were ire abundant at sampling locations outside the
thermal influence of Plant Alle . All other sunfishes were either more abundant
or equally abundant in the heat affected zone when compared with the other uplake
sampling location at the Allen intake area. White Crappie were not found at any
of the uplake sampling areas in icating lack of suitable habitat rather than thermal
avoidance. Based on the above iscussion, it appears that the lower (downlake)
41 -

i
TABLE 4
COMMON AND SCIENTIFIC NAMES OF FISHES COLLECTED FROM LAKE WYLIE, NORTH AND SOUTH CAROLINA
Family
N. C. W.R.C.I
Bio -Test
Species
Common Name
Study
Study
Lepisosteidae - Gars
Lepisosteus osseus (Linnaeus)
Longnose Gar.
X
X
Amiidae - Bowfins
Amia calva (Linnaeus)
Bowfin
X
X
Clupeidae - Herrings
Dorosoma ceoedianum (LeSueur)
Gizzard Shad
X
X
Dorosoma petenense (Gunther)
Threadfin Shad
X
X
Cyprinidae - Minnows and Carps
Carassius auratus (Linnaeus)
Goldfish
X
X
Cyprinus carpio Linnaeus
Carp
X
X
Hybognathus nuchalis Agassiz
Silvery Minnow
x
Nocomis _leptocephalus (Girard)
Bluehead Chub
x
Notemigonus crysoleucas (Mitchill)
Golden Shiner
x
x
Notropis analostanus (Girard)
Satinfin Shiner
x
x
Notropis hudsonis Clinton)
Spottail Shiner
x
x
Notropis procne (Cope)
Swallowtail Shiner
x
x
Catostomidae - Suckers
Carpiodes car io (Rafinesque)
River Carpsucker
x
Carpiodes cyprinus (LeSueur)
Quillback
x
x
Catostomus commersoni (Lacepede)
White Sucker
x
x
Erimyzon oblongus (Mitchili)
Creek Chubsucker
x
Erimyzon sucetta (Lacepede)
Lake Chubsucker
x
Ictiobus bubalus (Rafnisque)
Samllmouth Buffalo
x
x
Ictiobus cyprinellus (Valenciennes)-
Bigmouth Buffalo
x
Moxostoma collapsum (Cope)
V -lip Redhorse
x
Moxostoma macrole idotum (LeSueur)
Shorthead Redhorse
x
.Moxostoma pappillos.um (Cope)
Suckermouth Redhorse x
x
Moxostoma robustum (Cope)
Smallfin Redhorse
x
Ictaluridae - Freshwater Catfishes
Ictalurus catus (Linnaeus) -
White Catfish
x
x
Ictalurus melas (Rafinesque)
Black Bullhead
x
Ictalurus natalis (LeSueur)
Yellow Bullhead
x
Ictalurus nebulosus (LeSueur)
Brown Bullhead -
x
x
Ictalurus platycephalus (Girard)
Flat Bullhead
x
Ictalurus punctatus (Rafinesque)
Channel Catfish
x
x
Poeciliidae - Livebearers
. Gambusia affinis (Baird and Girard)
Mosquitofish
x
Perichthyidae - Temperate Basses
;; Morone chrysops (Rafinesque)
White Bass
x
x
Centrarchidae - Sunfishes
;; Ambloplites rupestris (Rafinesque)
Rock Bass
x
:; Enneacanthus gloriosus (Holbrook)
Bluespotted Sunfish
x
,c Lepomis auritus (Linnaeus)
Redbreast Sunfish
x
x
;; Lepomis cyanellus (Rafinesque)
Green Sunfish
x
42

Family
Species
_.Centrarchidae - Sunfishes
:; Lepomis gibbosus (Linnaeus)
• Lepomis gulosus (Cuvier)
• Lepomis macrochirus Rafinesque
:; Lepomis microlophus (Gunther)
:a Microoterus salmoides (Lacepede)
:; Pcmoxis annularis Rafinesque
• Pomoxis nigromaculatus (LeSueur)
Percidae
Etheostoma ni rum Refinesque
-` Perca flavescens (Mitchill)
Stizostedium vitreum (Mitchill)
Common Name
Pumpkinseed
Warmouth
Bluegill
Redear Sunfish
Largemouth Bass
White Crappie
Black Crappie
Johnny Darter
Yellow Perch
Walleye
1North Carolina Wildlife Resourcei Commission
Important Game or Pan Fish
Important Forage Fish
Stocked - 1954
43
N.C.W.R.C.1 Bio -Test
Study
Study
X
x
X
X
x
x
x
x
x
x
X
x
x
x
x
X
x
x

FISH SAMPLING LOCATIONS (FROM REFERENCE 3)
OUIfEPOYIER PLAINT ALLEN
Figure 15
44

portion of Lake Wylie is a more suitable sunfish habitat. There is some
avoidance of the heat affected zine by some sunfish species and an attraction
to it by others. The overall re�ult is that there are more sunfish by numbers
and by weight in the heat affected zone (excluding the discharge canal itself)
than in a comparable uptake arealunaffected by heat.
Water temperatures in the South (Fork Catawba River Arm of Lake Wylie receiving
the Plant Allen condenser cooling water were 8.9°F (4.9°C) to 19.2°F (12.0%)
higher than those of the naturally occurring Catawba River Arm during the year-
long Bio -Test study. Historically, monthly average condenser discharge tempera-
tures as high as 101.6°F (38.7°0) have been recorded. Field fish body tempera-
ture studies and laboratory tempe
rature avoidance studies were conducted to
determine if fish were able to areas influenced by the Allen thermal
plume. Results of these studiesshowed that "consistent, though small, dif-
ferences between fish body temperature and water temperature indicated that fish
utilized both heated and unheated areas of the thermally stratified Allen
discharge cove" even when temperatures exceeded 95°F (35°C) (Reference 3).
Oxygen concentrations and thermal conditions beneath the plume were always
sufficient to support fish life and did not serve as a barrier to fish movement.
These findings demonstrate that a substantial zone of unrestricted fish passage
exists in the Allen discharge cove (South Fork Arm) and also, that the fish move
into and out of the plume at al) times of the year.
The heated effluent from Plant Allen allows threadfin shad, an extremely important
forage fish, to survive the nathrally occurring lower lethal winter temperatures,
thereby reducing the need for pl rpetual restocking (Reference 3). Lake Wylie
threadfin shad populations servle as a major source for stocking other lakes in
North Carolina.
Fish living in the elevated toperature regions may exhibit increased metabolic
rates and, depending on food a this may result in a reduction of the
K factor. The K factor is a m,ailability,,
asure of the overall condition of a fish based
on length -weight relationships. No significant differences were found in the K
factors of fishes located inside the outside the heat affected zones (Reference 3).
It was further concluded that ')'any increase in the metabolic rate of fish in the
45

Allen discharge area was apparently compensated for by either an adequate food
supply or the movement of fish to other areas to feed" (Reference 3). No
difference in the growth rates of bluegill and redbreast sunfish were noted
between heat -affected and unaffected populations.
Spawning and fecundity information for common Lake Wylie fishes can be found
in Reference 3 and life history information in "Proposed Criteria for Water
Quality" (Reference 12). The fish of Lake Wylie are typical warm water, non -
migratory lake species that will spawn where suitable habitat exists. Peak
spawning activity of most species studied occurred during the expected times
throughout the study area; however, some species such as shad, quillbacks and
white catfish, apparently reached spawning conditions earlier in the Allen
discharge than elsewhere (Reference 3). The few white bass larvae obtained
during the study were collected from the Allen discharge canal, indicating
that they were able to successfully utilize the Allen discharge for spawning,
and also, that the heated effluent was not a barrier to their migration
(Reference 3). None of the above-mentioned effects can be considered detri-
mental to Lake Wylie Fish populations.
Larval fish sampling by Bio -Test (Reference 3) indicated that the greatest
densities existed from April through June in 1974. A total of ten taxa were
identified, including shad, largemouth bass, crappie, and other sunfish. The
greatest numbers of larval fish were shad. Larvae of the major sport and
forage fish were collected in the immediate discharge area of Allen indicating
that the temperatures during the critical spawning period were not too high to
exclude fish from this area.
The incidence of external parasitic infestations was low at all sampling
stations (Reference 3). Epistylis, an external parasite, was observed on
fish during all months of the study and from all areas sampled. It was found
to occur slightly more frequently at the Alien discharge areas. Since Epistylis
is found more frequently in areas of organic enrichment, the increased incidence
of infection may be due to the enriched condition of the South Fork. A study
of gas bubble disease conducted by the North Carolina Wildlife Resources Com-
mission revealed a low incidence of the disease in Lake Wylie (Reference 13).
Of the 1305 fish examined only three exhibited external symptoms of gas bubble
M

disease (Reference 13). No symptoms of gas bubble disease were observed in
fish collected during the Bio-Tlst study (Reference 3).
Since Allen has five independently operating units, it is improbable that all
units will be shut down at the same time. No evidence of cold shock has been
observed and no cold shock is expected.
47

LIST OF ABBREVIATIONS
ac
= acres
ac -ft
= acre-feet
BTU
= British Thermal Unit
°C
= degrees Celsius
cfs
= cubic feet per second
cm
= centimeters
OF
= degrees Fahrenheit
ft
= feet
ft
= square foot
Hr
= hour
in
= inches
km
= kilometers
m
meters
M3
= cubic meters
m3/s
= cubic meters per second
mi
- miles
mit
= square miles
mm
= millimeters
m.s.l.
= mean sea level
MW
= megawatts
s
= seconds
L:

REFERENCES
1. Federal Water Pollution Contol Acts, Amendments of 1972, Public Law
92-500.
2. Duke Power Company, 1972. Catawba Nuclear Station Environmental Report -
Construction Permit Stage.
3. Industrial Bio -Test. 1974.A baseline/predictive environmental investiga-
tion of Lake Wylie. Volumes I, II. Prepared for Duke Power Company,
Charlotte, North Carolina.
4. Duke Power Company, Supplemintal Information Request Transmitted to
EPA April 19, 1974.
5. Weiss, C. M., P. H. Campbell I, T. P. Anderson, and S. L. Pfaender. 1975.
The Lower Catawba Lakes: characterization of phyto- and zooplankton
communities and their relationships to environmental factors. University
of North Carolina, Chapel Hill, Department of Environmental Sciences
and Engineering Publication Number 389.
6. Ryan, P. J., and D. R. F. Harleman. 1973. An analytical and experimental
study of transient cooling pond behavior. Ralph M. Parsons"Laboratory
for Water Resources and Hydrodynamics, Report Number 161, M.I.T.
C7_) Letter dated February 2, 1976, from Mr.- Lewis Martin, North Carolina Depart-
ment of Natural and Econo esources, to Mr. Howard Zeller, U. S.
Environmental Protection Agency.
8. Lenat, D. R., and C. M. Weis. 1973. Distribution of benthic macroin-
vertebrates in Lake Wylie,}North Carolina -South Carolina. University of
North Carolina, Chapel Hillll, Department of Environmental Sciences and
Engineering Publication Number 311.
9. Endangered Species Committee. 1973. Preliminary list of endangered plant
and animal species in Northl Carolina. Department of Natural and Economic
Resources, State of North garolina, Raleigh.
10. U. S. Department of the Interior. 1974. United States list of endangered
fauna. Fish and Wildlife Service, Washington, D. C.
Il. McNaughton, W. D. 1965. Upper Catawba and Upper Yadkin River reservoirs.
North Carolina Wildlife Resources Commission
12. U. S. Environmental Protection Agency. 1973. Proposed criteria for Water
Quality. Volume I. Washington, D. C.
13. Miller, R. W. 1974. Inci
effluent. pp. 79-93. In.
Ecology. U. S. Atomic Ene
(1973).
Fence and cause of gas -bubble disease in a heated
J. W. Gibbons and R. R. Sharitz (eds) Thermal
-gy Commission Symposium Series, Conf 730505
49