NC0004961_Assessment of Balanced & Indigenous Populations_20090801

ASSESSMENT OF BALANCED AND INDIGENOUS POPULATIONS
IN MOUNTAIN ISLAND LAKE NEAR RIVERBEND STEAM STATION
NPDES Permit No. NC0004961
Principal Investigators:
Michael A. Abney
John E. Derwort
Keith A. Finley
DUKE ENERGY
Corporate EHS Services
McGuire Environmental Center
13339 Hagers Ferry Road
Huntersville, NC 28078
August 2009

ACKNOWLEDGMENTS
The authors wish to express their gratitude to a number of individuals who made significant
contributions to this report. First, we are much indebted to the EHS Scientific Services field
staff in carrying out a complex, multiple -discipline sampling effort that provides the
underpinning of this report. We would like to thank Glen Long for support in water quality
and sediment sample collections. Mark Auten, Kim Baker, Bob Doby, James Hall, Bryan
Kalb, Glenn Long, and Todd Lynn were vital contributors in completing fisheries collections
and sample processing. James Hall, Aileen Lockhart, Shannon McCorkle, and Jan Williams
contributed in macroinvertebrate sampling, sorting and taxonomic processing.
We would also like to thank multiple reviewers; including Penny Franklin, Duane Harrell,
Ron Lewis, and John Velte. The insightful commentary and suggestions from these
individuals and also between co-authors have benefited the report in myriad ways.
lu

TABLE OF CONTENTS
EXECUTIVESUMMARY....................................................................................................v
LISTOF TABLES............................................................................................................... vii
LIST OF FIGURES............................................................................................................ viii
CHAPTER1- INTRODUCTION........................................................................................1-1
REGULATORY CONSIDERATIONS..........................................................................1-2
CHAPTER 2- STATION OPERATION............................................................................ 2-1
METHODS......................................................................................................................
2-1
RESULTS AND DISCUSSION.....................................................................................
2-1
StationOperation.........................................................................................................
2-1
ThermalCompliance....................................................................................................2-2
Compliance with EPA Nomograph -Related Thermal Limits......................................2-2
CHAPTER 3- WATER AND SEDIMENT CHEMISTRY ...............................................
3-1
MATERIALSAND METHODS....................................................................................
3-1
Collection of Field Parameters, Water, and Sediment Chemistry Samples .................
3-1
AnalyticalMethods......................................................................................................
3-2
RESULTS AND DISCUSSION.....................................................................................
3-3
WaterQuality...............................................................................................................
3-3
RSS Ash Basin Effluent Selenium and Arsenic Mass Loading Estimates ..................
3-8
Sediment Elemental Analyses......................................................................................
3-9
CONCLUSIONS...........................................................................................................
3-10
CHAPTER 4- MACROINVERTEBRATES...................................................................... 4-1
MATERIALS AND METHODS.................................................................................... 4-1
RESULTS AND DISCUSSION..................................................................................... 4-1
Substrate....................................................................................................................... 4-1
Density......................................................................................................................... 4-2
TaxaAbundance.......................................................................................................... 4-2
CONCLUSIONS............................................................................................................. 4-3
CHAPTER5- FISH.............................................................................................................. 5-1
MATERIALS AND METHODS.................................................................................... 5-1
Winter and Summer Electrofishing Surveys................................................................ 5-1
Spring Electrofishing Surveys..................................................................................... 5-1
Fall Hydroacoustics and Purse Seine Surveys............................................................. 5-2
Trace Element Analyses.............................................................................................. 5-2
Balanced and Indigenous Assessment......................................................................... 5-2
RESULTS AND DISCUSSION..................................................................................... 5-3
Winter Electrofishing Surveys..................................................................................... 5-3
iii

Summer Electrofishing Surveys.................................................................................. 5-3
Spring Electrofishing Surveys..................................................................................... 5-4
Fall Hydroacoustics and Purse Seine Surveys............................................................. 5-5
CONCLUSIONS............................................................................................................. 5-6
LITERATURE CITED.......................................................................................................L-1
APPENDIX TABLES....................................................................................................... A-1
IV

EXECUTIVE SUMMARY
Per agreement with the North Carolina Department of Environment and Natural Resources
(NCDENR), annual monitoring of macroinvertebrates and fish was initiated in 1990 at
selected locations in Mountain Island Lake to evaluate potential impacts of the Riverbend
Steam Station (RSS) condenser cooling water discharge on balanced and indigenous
populations in Mountain Island Lake. Water quality and sediment samples collected also
provided information relative to the biological assessment. This report compares monitoring
data collected from 2004 — 2008 and past studies.
As in the past, during 2004 — 2008, RSS operated primarily as a peaking facility. Electric
generation occurred on 81% of available days, with the entire station operating at an average
of 48% of capacity over the period. Thermal limits specified in the RSS National Pollutant
Discharge Elimination System (NPDES) permit were not exceeded. Average monthly
condenser cooling water (CCW) discharge temperatures ranged from 4.9 °C (58.9 °F) in
February 2005, to 34.7 °C (94.4 °F) in August 2007. These temperatures followed a regular
seasonal pattern and were within the range of previously reported values. The discharge
water temperature of RSS was continually monitored to ensure compliance and to assist in
the investigation of potential impacts to downstream biota.
Water quality in Mountain Island Lake during 2004 — 2008 was similar to previous years.
Seasonal thermal stratification, and dissolved oxygen concentrations were representative of
historical ranges. Lake -wide, concentrations of major nutrients, similar to historical levels,
continued to result in Mountain Island Lake being classified as oligotrophic to mesotrophic
during 2004 — 2008. Typically elevated concentrations of dissolved and suspended material,
as well as nutrients entering the lake from the McDowell Creek drainage were slightly lower
during 2004 — 2008.
Mass loading of selenium and arsenic from the RSS ash basin outfall during 2004 — 2008
was similar to historical trends, except for reductions observed in arsenic loading over the
2007 — 2008 period. Mountain Island Lake concentrations of aqueous trace elements
remained generally low, consistent with low levels of turbidity and suspended solids.
March 2008 arsenic concentrations in fine surficial sediments were elevated downstream of
RSS in the forebay of Mountain Island Hydroelectric Station (MINS) with respect to uplake
v

concentrations, with samples just downstream of the RSS ash basin effluent confluence
yielding the highest concentrations. While the 2008 samples were likely influenced by a
slight relocation of the sampling site due to difficulty in obtaining material other than coarse
sand at the former location, MIHS forebay sediment sampling continues to indicate a slight,
gradual increase in arsenic concentrations over recent years. Sediment concentrations of
selenium were consistently low lake -wide. As a whole, 2004 — 2008 Mountain Island Lake
water and sediment chemistry continue to indicate the waterbody remains capable of
sustaining balanced and indigenous aquatic communities. Trace element concentrations
measured in Mountain Island Lake common carp, sunfish, and largemouth bass since 1988
remain well below values of regulatory concern.
As in previous years, annual samples of the macroinverterbrate community collected uplake,
downlake, and adjacent to the RSS discharge area during 2004 — 2008 were comprised
primarily of Oligochaeta, Diptera, and Corbicula. Comparison of macroinvertebrate
densities and taxa abundance continues to indicate no apparent adverse effect of the heated
discharge on the macroinvertebrate community in the vicinity of the discharge.
Electrofishing samples have shown a persistent and stable fish community present in the
littoral portions of Mountain Island Lake around RSS from 2004 to 2008. The assorted fish
species typically found in Mountain Island Lake encompass a range of trophic groups
including insectivores, omnivores, and piscivores that indicate a balanced and indigenous
fish community. Forage fish population densities were comparable to those measured
previously at Mountain Island Lake and to other Catawba River reservoirs of similar trophic
status. The introduction of alewife, the inherent, temporal variability of clupeid populations,
and the historical flux of Mountain Island Lake between oligotrophic and mesotrophic water
quality classifications are all factors contributing to the unpredictable nature of forage fish
densities.
Based on the diversity and numbers of individuals in the Mountain Island Lake littoral fish
community during winter, spring, and summer; the range of trophic groups represented; the
lack of accumulation of selenium, arsenic, mercury, or zinc in fish flesh; and the regular
availability of forage fish to limnetic predators; it is concluded that the operation of RSS has
not impaired the protection and propagation of a balanced and indigenous fish community in
Mountain Island Lake.
vi

LIST OF TABLES
Table Title Page
1-1 Biological and water quality monitoring locations on Mountain Island Lake............ 1-5
2-1 RSS monthly units 4 through 7 (U4 — U7), monthly average (Av), and annual
station coal-fired capacity factors (percent) during 2004 — 2008 ............................... 2-3
3-1 Analytical methods used to determine chemical and physical constituents in
Mountain Island Lake during 2004 — 2008............................................................... 3-12
4-1 Densities (number/m2) of macroinvertebrates collected annually from Location B
(upstream of RSS) from 2000 — 2008......................................................................... 4-4
4-2 Densities (number/m2) of macroinvertebrates collected annually from Location F
(RSS discharge) from 2000 — 2008............................................................................. 4-8
4-3 Densities (number/m2) of macroinvertebrates collected annually from Location G
(downstream of RSS) from 2000 — 2008.................................................................. 4-11
5-1
Number of individuals and number of species in winter electrofishing surveys
from three locations (B, F, and G) in Mountain Island Lake, 1994 — 1999, 2000 —
2003, and 2004 — 2008................................................................................................
5-8
5-2
Number of individuals and number of species in summer electrofishing surveys
from three locations (B, F, and G) in Mountain Island Lake, 1991 —1993, 1994 —
1999, 2000 — 2003, and 2004 — 2008..........................................................................
5-9
5-3
Number of individuals, biomass, and number of species collected during spring
electrofishing of five 300-m transects downlake and five 300-m transects uplake
of the RSS discharge canal in Mountain Island Lake, 1993 — 1997, 1999 — 2008...5-10
5-4
Number of individuals and number of species collected during spring
electrofishing of ten 300-m transects in the vicinity of the RSS discharge canal
in Mountain Island Lake, 1994 — 1997 and 1999, 2000 — 2003, and 2004 — 2008...
5-11
5-5
Number, percentage, average length, average density, and forage fish population
estimates in Mountain Island Lake, 1993 — 1997, 1999 — 2008, from mid-
September purse seine and hydroacoustic surveys ...................................................
5-12
vii

LIST OF FIGURES
Figure Title Page
1-1 Sampling locations on Mountain Island Lake. Duke Energy historical location
identifiers are listed in parentheses............................................................................. 1-6
2-1
Average monthly CCW discharge temperatures (solid circles) and monthly range
3-23
3-19
daily average temperatures (open circles), displayed over days per month of RSS
3-23
3-20
coal-fired generation during 2004 — 2008...................................................................
2-4
2-2
Average monthly downstream temperatures (solid circles) and monthly range of
3-24
3-22
daily average temperatures (open circles)...................................................................
2-4
3-1
Winter profiles of temperature (°C; ■) and dissolved oxygen (mg/L; ❑) at the
3-25
3-24
Mountain Island Lake forebay, Location G..............................................................
3-15
3-2
Summer profiles of temperature (°C; ■) and dissolved oxygen (mg/L; ❑) at the
3-25
3-26
Mountain Island Lake forebay, Location G..............................................................
3-16
3-3
Semi-annual specific conductance profiles in Mountain Island Lake, 2004 —
3-26
2008...........................................................................................................................
3-17
3-4
Semi-annual pH profiles in Mountain Island Lake, 2004 — 2008 .............................
3-18
3-5
Distribution of Mountain Island Lake specific conductance .....................................
3-19
3-6
Distribution of Mountain Island Lake pH.................................................................
3-19
3-7
Distribution of Mountain Island Lake total alkalinity concentrations ......................
3-19
3-8
Distribution of Mountain Island Lake turbidity........................................................
3-20
3-9
Distribution of Mountain Island Lake total suspended solids concentrations...........
3-20
3-10
Distribution of Mountain Island Lake ammonia nitrogen concentrations .................
3-20
3-11
Distribution of Mountain Island Lake nitrate+nitrite nitrogen concentrations.........
3-21
3-12
Distribution of Mountain Island Lake total nitrogen concentrations ........................
3-21
3-13
Distribution of Mountain Island Lake soluble orthophosphate concentrations........
3-21
3-14
Distribution of Mountain Island Lake total phosphorus concentrations ...................
3-22
3-15
Distribution of Mountain Island Lake calcium concentrations .................................
3-22
3-16
Distribution of Mountain Island Lake magnesium concentrations ...........................
3-22
3-17
Distribution of Mountain Island Lake sodium concentrations . .................................
3-23
3-18
Distribution of Mountain Island Lake potassium concentrations .............................
3-23
3-19
Distribution of Mountain Island Lake chloride concentrations .................................
3-23
3-20
Distribution of Mountain Island Lake sulfate concentrations ...................................
3-24
3-21
Distribution of Mountain Island Lake iron concentrations .......................................
3-24
3-22
Distribution of Mountain Island Lake manganese concentrations ............................
3-24
3-23
Distribution of Mountain Island Lake aluminum concentrations ..............................
3-25
3-24
Distribution of Mountain Island Lake silica concentrations .....................................
3-25
3-25
Distribution of Mountain Island Lake arsenic concentrations ..................................
3-25
3-26
Distribution of Mountain Island Lake barium concentrations ..................................
3-26
3-27
Distribution of Mountain Island Lake copper concentrations ...................................
3-26
viii

LIST OF FIGURES, Continued
Figure Title Page
3-28 Distribution of Mountain Island Lake soluble copper concentrations ...................... 3-26
3-29 Distribution of Mountain Island Lake mercury concentrations ................................ 3-27
3-30 Distribution of Mountain Island Lake zinc concentrations ....................................... 3-27
3-31 Average annual RSS ash basin discharge and arsenic loading to Mountain Island
Lake, 1992 —2008 ..................................................................................................... 3-28
3-32 Average annual RSS ash basin discharge and selenium loading to Mountain
Island Lake, 1992 — 2008........................................................................................ 3-28
3-33 Distribution of arsenic concentrations in sediment fines sampled from Mountain
Island Lake upstream (US) and downstream (DS) of the RSS ash basin outfall...... 3-29
3-34 Distribution of selenium concentrations in sediment fines sampled from
Mountain Island Lake upstream (US) and downstream (DS) of the RSS ash basin
outfall........................................................................................................................ 3-29
4-1 Density (number/m2) of macroinvertebrates collected annually during 2000 —
2008 from Mountain Island Lake..............................................................................4-15
4-2 Total number of macroinvertebrate taxa collected annually during 2000 — 2008
from Mountain Island Lake.......................................................................................4-15
4-3 Density (number/m2) of Oligochaeta, Diptera, and Corbacula collected annually
during 2000 — 2008 from Location B in Mountain Island Lake ............................... 4-16
4-4 Density (number/m2) of Oligochaeta, Diptera, and Corbacula collected annually
during 2000 — 2008 from Location F in Mountain Island Lake ................................ 4-16
4-5 Density (number/m2) of Oligochaeta, Diptera, and Corbacula collected annually
during 2000 — 2008 from Location G in Mountain Island Lake ............................... 4-17
5-1 Number of fish (a), and fish species (b) collected from electrofishing a 100-m
transect at each of three locations (B, F, and G) during winter electrofishing in
Mountain Island Lake, 1994 — 2008......................................................................... 5-13
5-2 Number of fish (a), and fish species (b) collected from electrofishing a 100-m
transect at each of three locations (B, F, and G) during summer electrofishing in
Mountain Island Lake, 1994 — 2008......................................................................... 5-14
5-3 Selenium concentrations in muscle tissue from common carp (a), sunfish (b), and
bass (c) from four locations (A, B, C, and G) in Mountain Island Lake, 1994 —
2008. The only complete common carp samples were Locations A (2004 —
2006) and C (2005)................................................................................................... 5-15
5-4 Arsenic concentrations in muscle tissue from common carp (a), sunfish (b), and
bass (c) from four locations (A, B, C, and G) in Mountain Island Lake, 1994 —
2008. The only complete common carp samples were Locations A (2004 —
2006) and C (2005)................................................................................................... 5-16
ix

LIST OF FIGURES, Continued
Figure Title Page
5-5 Mercury concentrations in muscle tissue from common carp (a), sunfish (b), and
bass (c) from four locations (A, B, C, and G) in Mountain Island Lake, 1995 —
2008. The only complete common carp samples were Locations A (2004 —
2006) and C (2005)................................................................................................... 5-17
5-6 Zinc concentrations in muscle tissue from common carp (a), sunfish (b), and bass
(c) from four locations (A, B, C, and G) in Mountain Island Lake, 1997 — 2008.
The only complete common carp samples were Locations A (2004 — 2006) and
C(2005).................................................................................................................... 5-18
X

CHAPTER 1
INTRODUCTION
Riverbend Steam Station (RSS) is located northwest of Charlotte, in Gaston County, North
Carolina on 25 -km Mountain Island Lake, one of the 11 Catawba River reservoirs (Figure 1-
1). The RSS began commercial service in 1929. Three of the oldest generating coal-fired
units (1 — 3) were retired from service in the 1970s. The station presently has four operating
coal-fired units (4 — 7), with a combined generating capacity of 454 MWe-net. Units 4 and 5
began commercial operation in 1952, and units 6 and 7 followed in 1954. In recent years
RSS generation has typically been used to meet peak electric power demand, and as such,
short-term and cyclic operation of selected units is common. In the 1990s, the four coal-fired
units were modernized to improve reliability in light of their role in meeting electrical load
peaks; the above -listed unit capacities reflect those modifications. Four additional
combustion turbine units located at the RSS site, each of 30 MWe-net capacity, are not
condenser -cooled and therefore do not reject heat to Mountain Island Lake.
The RSS coal-fired units 4 — 7 utilize Mountain Island Lake as a source for once -through
condenser cooling water (CCW). The CCW intake and discharge structures for RSS are
located approximately 10.6 and 22.0 river km, respectively, downstream of Cowan's Ford
Hydroelectric Station (CFHS; impounding Lake Norman). The RSS CCW discharge
structure is approximately 2.7 km upstream of Mountain Island Hydroelectric Station
(MIHS). Each generating unit has two CCW pumps that can be operated independently.
Station operators run either one or two pumps per unit depending on intake water
temperature, discharge temperature limits, and operational efficiency. The four RSS once -
through -cooled units are capable of withdrawing CCW at a combined maximum rate of 18.2
m3/s (642 cfs).
1-1

REGULATORY CONSIDERATIONS
Current National Pollutant Discharge Elimination System (NPDES; NCDENR 2005)
permitted thermal limits for RSS CCW effluent, based upon an approved 316(a) thermal
variance, are:
• a monthly average CCW discharge (i.e , end -of -pipe) temperature limit of 35 °C (95 °F),
and
• a daily average downstream water temperature limit of 32.0 °C (89.6 °F) measured at
Mountain Island Hydroelectric Station.
The RSS NPDES permit stipulates additional delta temperature (AT) thermal effluent limits
(i.e., maximum permissible temperature increase above ambient, or upstream conditions),
based on the Environmental Protection Agency (EPA) nomograph (USEPA 1976), under
specific operational conditions. The EPA nomograph limits are intended to protect
warmwater fish from "cold shock" in the event of a winter season plant shutdown. These
operational constraints (paraphrased below) were originally approved by the North Carolina
Department of Environment and Natural Resources NCDENR in 1993, and incorporated into
subsequent RSS NPDES permits, including the present permit:
• when only one RSS control system is operating and the inlet water temperature ranges
from 2.5 °C (36.5 °F) to < 12 8 °C (55 W), then the average daily discharge water
temperature limit is two times the inlet temperature (°F) minus 23, and
• when only one RSS control system is operating and the inlet water temperature is < 2.5 °
C (36.5 °F), then the average daily discharge water temperature limit is 10 cC (50 °F)
Assessment of the potential influence of thermal discharges on biological communities is a
key component of thermal discharge variances granted under section 316(a) of the Clean
Water Act (CWA). The term "balanced, indigenous community" [40CFR125.71(c)] is
synonymous with the term "balanced, indigenous population" in the CWA, and refers to a
biotic community typically characterized by diversity, the capacity to sustain itself through
cyclic seasonal changes, presence of necessary food chain species and a lack of domination
by pollution tolerant species. Such a community may include historically non-native species
introduced in connection with a program of wildlife management and species whose
presence or abundance results from substantial, irreversible environmental modifications
(USEPA 1977).
1-2

Pursuant to an agreement with the NCDENR, annual monitoring of macroinvertebrates and
fish was initiated in 1990 at selected Mountain Island Lake locations in the vicinity of RSS.
The objectives of this ongoing monitoring program were to assess macroinvertebrate and fish
populations with respect to operation of RSS, and provide an indication of the suitability of
approved thermal limits as defined in the RSS NPDES permit. Additionally, water quality
and sediment samples were evaluated to provide information relevant to the biological
assessment, but also to characterize potential impacts to the reservoir relating to the
permitted RSS ash basin discharge.
Water quality and biological samples are collected each year from established Mountain
Island Lake sample locations (A — G) upstream, within the immediate influence of, and
downstream of the RSS thermal discharge. Additionally, fish are collected from 10 shoreline
segments in the vicinity of RSS in the spring (Table 1-1 and Figure 1-1). Finally, sediment
samples are collected generally once per permit period at selected locations upstream and
downstream of the RSS ash basin discharge. Conventional Duke Energy sample location
numbers associated with Locations A through G are provided in Table 1-1 and Figure 1-1 for
reference to previously submitted reports. Locations A and B are upstream of the RSS
thermal discharge (Location A is also upstream of the station CCW intake) and for the
purposes of the 316(a) monitoring program, these two locations were considered reference
sites. Location C is immediately downstream of the RSS ash basin discharge. This location
is used in conjunction with Location B to evaluate water quality and sediment chemistry in
relation to the potential impacts of the RSS ash basin discharge. Location D is situated in the
McDowell Creek arm of Mountain Island Lake and is utilized to characterize potential water
quality impacts resulting from inflows from that extensively developed sub -catchment.
Location E represents the area where Charlotte -Mecklenburg Utilities Department (CMUD)
withdraws raw lake water for drinking water supply; water chemistry is sampled to assist in
characterizing Mountain Island Lake water quality at the site. Location F is adjacent to the
RSS CCW thermal discharge and is utilized to evaluate potential near -field effects on aquatic
biota from heated effluents. Finally, Location G is situated at the Mountain Island Lake
forebay and represents a far -field site for evaluating impacts of the RSS thermal discharge.
Previous studies of this site have established that the existing limits on the thermal
component of the discharge of RSS have assured the protection and propagation of balanced,
indigenous populations in Mountain Island Lake (Duke Power Company 1994; Duke Power
2001 and 2004). This report presents results related to RSS operations from data collected
1-3

since submittal of the previous (2004) summary report and includes data collected from 2004
— 2008 (Note: January 2004 sediment trace element data were included in the previous
report). Also, the 2004 — 2008 data are compared with other environmental monitoring
programs conducted in this watershed.
1-4

Table 1-1. Biological and water quality monitoring locations on Mountain Island Lake.
1 Latitude/longitude data obtained from TOPOI USGS mapping software (National Geographic Holdings, Inc 2001)
River km (mi)
Report
Duke
County
Description
Assessments
Upstream of
Location
Energy
Mountain
Latitude'
Longitude'
Designation
Location
Island
N
W
No.
Hydroelectric
Station
A
16.0
Gaston I
Catawba River at entrance to Duck Cove
Water quality
17.2
35° 22.894'
80° 58.817
Mecklenburg
Sediments
(10.7)
Fish
Mecklenburg
Catawba River upstream and north of RSS ash
Water quality
11.6
35° 22.358'
80° 57.363'
B
2776
basin discharge; eastern side of lake
Sediments
(7 2)
Macroinvertebrates
Fish
C
277.5
Gaston /
Catawba River downstream of RSS ash basin
Water quality
10.8
35° 22.009'
80° 57.085'
Mecklenburg
discharge and upstream of McDowell Creek
Sediments
(6 7)
confluence, western side of lake
D
277.3
Mecklenburg
McDowell Creek cove, approx. 250 m upstream
Water quality
100
350 22.240'
800 56.510'
from Catawba River mainstem confluence
6.2
E
277.0
Mecklenburg
Catawba River at Charlotte -Mecklenburg Water
Water quality
5.8
35° 20.922'
80° 56 621'
Treatment plant intakes
3.6
F
276.5
Gaston
RSS condenser cooling water discharge canal
Water quality
27
35° 21.320'
80° 58171'
Macroinvertebrates
(17)
Fish
G
275.0/
Gaston
Mountain Island Dam forebay (275 0);
Water quality
0.2-06
35° 20.069'
80° 59 203'
275.5
Cove upstream of the Mt. Holly Water Treatment
Sediments
(0.1-0.4)
35° 20 099'
80° 59.428'
plant intake (275 5)
Macroinvertebrates
Fish
1 Latitude/longitude data obtained from TOPOI USGS mapping software (National Geographic Holdings, Inc 2001)

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�
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`,,
s
Z
1
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IWO
,v° � bt i ���� �'Y „ys ,-� .Ir• i' - x `rfg,jiry��'�r���+'�"J' };`, 7`'' ry`;rV��\ { r �j�
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`,
5. ,( a��t �' �w'!t� „��~-T i Tv�, �-Jl ^.,t..�•�''`,'�1'�`t{`7t�'� �.�.,,�.m� & .�-�� �t�'�
t �� slartd '11711
,,JI
00.59000 W 00.59000 W 80.57000 W 80°56000 W WG50400`550 O W
Y �bllti I
Figure 1-1. Sampling locations on Mountain Island Lake. Duke Energy historical location identifiers
are listed in parentheses.
1-6

CHAPTER 2
STATION OPERATION
METHODS
Riverbend Steam Station (RSS) intake, discharge, and downstream water temperatures were
continuously monitored during 2004 — 2008 to ensure thermal permit compliance. Thermal
compliance data were obtained from National Pollutant Discharge Elimination System
(NPDES) discharge monitoring reports. Station generating unit capacity data were compiled
from the Duke Energy MicroGads and predecessor databases.
Until April 9, 2008, RSS downstream water temperatures were measured at the Mountain
Island Hydroelectric Station (MIHS) tailrace. During periods of very low Catawba River
flow, however, particularly as experienced during recent drought years, MIHS generation
was limited. In the absence of hydroelectric generation during warmer months, daytime
temperatures in the quiescent tailwater pool could be appreciably warmed by incident solar
radiation, in excess of upstream (upper pool) thermal conditions in deeper lake strata which
correspond to MIHS penstock elevations. Therefore, Duke Energy sought and was granted
permission from North Carolina Department of Environment and Natural Resources
(NCDENR) to relocate the RSS downstream thermal compliance point upstream of the
MIHS. On April 9, 2008 the downstream thermal sensor was relocated to the Mountain
Island Dam forebay at a depth of 9 in; a depth that historical monitoring data indicated
corresponded to tailwater temperatures during periods of hydroelectric generation.
RESULTS AND DISCUSSION
Station Operation
The RSS has in recent years operated as a peaking facility, and operation during January
2004 through December 2008 was consistent with this role of peak electric load generation.
Electric generation (from one or more coal-fired units) occurred on 81% of days between
January 1, 2004 and December 31, 2008 (Figure 2-1). For the entire five-year period, RSS
2-1

coal-fired units operated at an average of about 48% of capacity (i.e., actual/potential station
generation), ranging from 39.6% in 2004 to 56.3% in 2007 (Table 2-1). Month-to-month
generation capacity factors varied substantially by season and year, depending on load
demand and unit outages. Maximum monthly average capacity was achieved during the June
— August period in each of the five years, reflecting greater utilization of RSS for periods of
peak summertime electric demand.
Thermal Compliance
The thermal limits of the NPDES permit of RSS were not exceeded during the 2004 — 2008
period. The average monthly CCW discharge water temperature ranged from 14.9 °C (58.9
°F) in February 2005, to 34.7 °C (94.4 °F) in August 2007 (Figure 2-1). These temperatures
followed a regular seasonal pattern and were within thermal ranges previously reported
(Duke Power Company 1993, 1994; Duke Power 2004). Likewise, daily average
downstream temperatures measured at MIHS reflected typical seasonal variability, ranging
from 8.1 °C (46.5 °F) on January 29, 2004 to 31.9 °C (89.5 °F) on August 10, 2007 (Figure 2-
2). During 2004 — 2008, maximum average monthly CCW outlet and downstream daily
average temperatures were recorded in August 2007. These thermal maxima were influenced
by below normal total precipitation in August 2007 (1.04 cm versus a normal 9.45 cm), as
well as appreciably warmer than normal ambient August 2007 air temperatures (587 cooling
degree-days versus a normal of 415; NOAA 2008a).
Compliance with EPA Nomograph -Related Thermal Limits
The EPA nomograph thermal limits (see Chapter 1) apply during times of relatively low
receiving stream temperatures, and when only one of the RSS coal-fired units control
systems is operational. A nomograph limit is calculated by applying a maximum permissible
temperature increase (OT) above ambient, i.e., CCW inlet temperature. These limits were
established to protect resident warmwater fish from potential "cold shock" in the event of a
unit trip or sudden unit shutdown, which would lead to rapid cooling in the portion of
Mountain Island Lake affected by the RSS thermal plume. Coincident wintertime operation
of more than one RSS control system frequently restricted the applicability of nomograph
thermal limits. During 2004 — 2008, thermal effluent temperatures complied with applicable
nomograph thermal restrictions at all times.
2-2

Table 2-1. RSS monthly units 4 through 7 (U4 - U7), monthly average (Av), and annual station coal-fired capacity factors (percent)
during 2004 - 2008.
N
W
2004
2005
2006
2007
2008
Month
U4
U5
U6
U7
Av
U4
U5
U6
U7
Av
U4
U5
U6
U7
Av
U4
U5
U6
U7
Av
U4
U5
U6
U7
Av
Jan
668
661
763
277
580
357
404
419
423
404
00
00
51
54
29
179
164
324
543
325
594
53.8
592
589
581
Feb
708
672
743
00
50.3
174
454
322
390
339
304
308
452
462
394
469
520
637
625
574
464
45.5
50.5
589
511
Mar
299
449
464
29
299
715
682
472
773
654
364
341
423
519
422
313
312
320
313
315
413
644
69.2
64.2
610
Apr
594
51.1
45.2
688
56.3
305
57.9
0.0
655
374
67.3
52.5
74.5
775
693
473
493
578
539
52.7
76.1
78.8
74.2
825
78.0
May
540
704
740
774
701
423
387
16.9
17.4
268
34.9
36.3
42.6
46.9
410
643
637
647
645
64.4
689
637
654
657
659
Jun
340
658
74.5
80.2
66.0
496
485
63.9
642
578
68.4
646
673
767
697
587
579
615
62.4
60.4
85.3
83.6
750
822
81.0
Jul
422
49.8
630
653
56.6
717
674
645
578
646
780
789
810
789
793
775
725
710
682
718
701
59.2
668
512
61.4
Aug
524
457
454
581
506
75.6
727
732
785
751
78.9
74.7
81.3
74.3
774
788
763
757
76.1
76.6
47.2
43.0
570
544
513
Sep
119
10.0
265
268
20.2
619
62.1
68.9
68.7
66.0
3.7
4.1
19.0
12.9
110
63.0
32.7
63.4
73.4
59.9
24.4
23.8
293
33.1
28.2
Oct
00
0.0
7.9
10.2
5.1
35.7
421
368
480
410
59.7
603
570
122
451
781
52
439
755
522
00
00
10.4
127
6.6
Nov
0.0
0.0
0.4
3.0
08
20.9
25.6
149
00
138
665
657
6.0
699
496
529
658
698
612
629
104
124
262
382
23.6
Dec
136
19
159
135
118
469
410
375
3.3
30.1
355
352
462
417
404
563
595
569
46.7
543
173
16.0
257
269
223
Annual
39.6
46.2
47.3
56.4
49.0
N
W

45 113
Monthly average limit
40 4 q p 104
35 4Q1 IQ 4414 QQ 95
30 86
U
25 0 0
CD
%a y
CD
E 20 68 m
9 TI
15 59
10 50
5 41
O - — - -- -- — 32
30 - -----""F'-- --"- -- --'�—' ----- - --- — '----'- - - ----+-'-- - -----
25 —'—�- --}— — --- -
w , 5 — --
N 10
0 5
0
2004 2005 2006 2007 2008
Date
Figure 2-1. Average monthly CCW discharge temperatures (solid circles) and monthly range
daily average temperatures (open circles), displayed over days per month of RSS
coal-fired generation during 2004 — 2008.
35
32
30
25
U
uD 20
m
`m
CL
E 15
F�
10
5
95
86
77
m
68 3
CD
CD
c
59
50
41
0 I- i 32
2004 2005 2006 2007 2008
Figure 2-2. Average monthly downstream temperatures (solid circles) and monthly range of
daily average temperatures (open circles).
2-4

CHAPTER 3
WATER AND SEDIMENT CHEMISTRY
MATERIALS AND METHODS
Collection of Field Parameters, Water, and Sediment Chemistry Samples
Mountain Island Lake water quality was monitored at six locations (A, B, C, D, E, and G;
Figure 1-1 and Table 1-1) semiannually (summer and winter) during 2004 — 2008. Sample
locations ranged (as ordered above) from the furthest upstream site at Cowan's Ford
Hydroelectric Station (CFHS) tailwater to the furthest downstream site at the Mountain
Island Hydroelectric Station (MIHS) forebay. Locations were the same as those monitored
in prior years (Duke Power Company 1994; Duke Power 2001 and 2004). In-situ analyses
were performed by Duke Energy Scientific Services personnel? At each location, vertical
profiles of in-situ parameters (temperature, dissolved oxygen, pH and specific conductance)
were collected with a Hydrolab DataSondeo.
Water samples for the laboratory analyses listed in Table 3-1 were collected with a
Kemmerer bottle at surface (0.3 m) at each location, and approximately one meter above
bottom at the MIHS forebay (Location G). Samples for soluble nutrients (i.e., ammonia -N,
nitrtate+nitrite-N, and orthophosphate) were filtered (0.45-µm) in the field. Additional
samples collected for the analysis of soluble copper, beginning in 2005, were also field -
filtered. All samples were preserved (acidified or iced) in the field immediately following
collection.
Mountain Island Lake sediment sampling was conducted on March 6, 2008 (data from
sediment samples collected January 30, 2004 were summarized previously; Duke Power
2004). Sediment cores were obtained from four locations (A, B, C, and G; Figure 1-1 and
Table 1-1), including an upstream reference site (Location A), locations immediately
upstream and downstream of the ash basin outfall (Locations B and C, respectively) and the
MIHS forebay (Location G). Ten replicate cores were obtained from each location with a K-
2 The Duke Energy Scientific Services organization is presently certified by the North Carolina Division of
Water Quality (DWQ) under the Field Parameter Certification program (certificate number 5193) However,
all field chemistry data represented in this report are uncertified data; i.e., not collected for effluent compliance
monitoring purposes.
3-1

B° gravity corer, or in shallower depths, a hand corer fitted with cellulose acetate butyrate
core liner tubes. Upon collection, sediment cores were sealed with polyethylene end caps,
with site water overlaying the intact water -sediment interface. Cores were maintained in an
upright position to preserve the sediment -water interface, stored on ice, and subsequently
refrigerated upon return to the laboratory.
Analytical Methods
Analytical methods and sample preservation techniques employed during 2001 — 2005 are
summarized in Table 3-1. Since 2001, trace element concentrations of water samples have
been analyzed as "total recoverable" elemental concentration, which incorporates a dilute
acidic digestion of the sample (USEPA 1994). This technique was distinct from the
analytical method for trace elements employed during the period 1988 — 2000, when acid -
preserved samples were analyzed by atomic absorption spectroscopy direct injection, i.e.,
samples were not acid -digested. With minor exceptions, laboratory water quality analyses
were performed by Duke Energy Corporate EHS Analytical Laboratory, Huntersville, NC
(North Carolina DWQ Laboratory Certification program, certificate number 248). In several
instances, selected parameters were analyzed by an alternate state -certified commercial
laboratory. Prism Laboratories, Inc., Charlotte, NC (NC DWQ certificate number 402)
provided turbidity analyses (except for February 2004 samples), total solids analyses for
2005 — 2008, total suspended solids for 2005 samples, and mercury analyses for February
2007 and February 2008 samples.
Because the uppermost sediment strata was of primary concern in evaluating recent
deposition and trace element bioavailability, sediment core samples were processed in the
laboratory to remove surficial material (i.e., silt + clay fractions) from the uppermost stratum
of each core. Upon return to the laboratory, fine-suspendable sediments were siphoned from
the uppermost 2 mm of each sediment core, sieved through a 63-µm plastic (Nitex°) screen,
and then deposited onto a pre -weighed 0.45-µm Millipore® acetate membrane filter. Filters
were subsequently dried at room temperature and analyzed by non-destructive neutron
activation analysis at the Nuclear Services Laboratory, North Carolina State University,
Raleigh, NC. Quality assurance measures for dry weight -based selenium and arsenic
concentrations (expressed as µg element/g sediment) employed analyses of filter blanks,
internal standards, and National Institute of Standards and Technology or International
Atomic Energy Agency reference materials for calibration.
3-2

Data analyses employed both statistical and graphical methods. Time series plots were used
to assess seasonal and inter -annual trends in CCW and lake temperatures. Box and whisker
plots (showing median, 25% and 75% quartiles, and data range) were produced for selected
water chemistry analytes, by sample location and pre -defined year groupings, to permit
temporal and spatial comparisons with historical data. Trace element concentrations in
Mountain Island Lake sediments were analyzed by non -parametric procedures (Wilcoxon
rank sum and Kruskal-Wallis tests) for effects by year and location, respectively (SAS
Institute Inc. 2002 — 2004) where statistical treatment of analytical results was not limited by
the prevalence of below -detection values. In all instances where analyte concentrations were
less than the laboratory reporting limit, the reporting limit value was represented graphically.
RESULTS AND DISCUSSION
Water Quality
Because of the relatively small catchment and short hydrologic retention time of Mountain
Island Lake (e.g., < 1 to 12 days; Bales et al. 2001), the thermal structure of the reservoir is
substantially influenced by the linkage of controlled releases from the upstream CFHS and
outflows from MINS, combined with the thermal plume from RSS. A submerged weir
immediately upstream of Cowans Ford Dam results in inflows to Mountain Island Lake
during summer hydro generation that are thermally representative of the warmer Lake
Norman epilimnion. The high flow-through rates, small reservoir catchment, and relatively
shallow reservoir morphometry all serve to limit the establishment of a strong thermal
gradient, particularly in areas of the lake upstream of RSS.
Typical seasonal trends during 2004 — 2008 were observed for Mountain Island Lake
temperature and dissolved oxygen (Figures 3-1 and 3-2). Forebay thermal profiles were
similar to results of previous monitoring (Duke Power Company 1994; Duke Power 2001,
2004). During the summers of 2004 — 2008, the deeper regions of the reservoir became
weakly stratified thermally, and dissolved oxygen levels declined gradually with increasing
depth below the uppermost mixed layer (i.e., top 3 to 5 m) of the water column (Figure 3-2).
As in previous years, the occurrence of summertime hypolimnetic anoxia at the MIHS
forebay was variable year-to-year, with anoxic conditions occurring most years at elevations
in the reservoir corresponding to the lower limit of the MIHS penstocks, i.e., normally in the
bottom 3 to 4 meters of the water column. Thermal stratification was slightly less
3-3

pronounced for the August 2005 sampling compared to other years, and can be linked to lack
of anoxic conditions at the time in those bottom waters.
Surface specific conductance (Figures 3-3 and 3-5) ranged lake -wide from 49.9 to 227
µS/cm, with maximum values typically occurring in the McDowell Creek cove (Location D).
This finding is consistent with recent monitoring trends and is in agreement with data
reported by other researchers (Bales et al. 2001; Buetow 2003). McDowell Creek receives a
substantial point source discharge from the recently enlarged Charlotte -Mecklenburg
Utilities 12 -MGD McDowell Creek Wastewater Treatment Plant (WWTP), as well as non -
point source contributions due to increasing (primarily residential) development in the
watershed. Specific conductance values measured in the lower water column (i.e., 3 to 4 in
deep) at Location D were frequently among the greatest encountered lake -wide. Near -
surface specific conductance values at this location were exceptionally greater in February
2005, however, likely reflecting warmer, buoyant inflows from McDowell Creek relative to
cooler ambient lake temperatures at the time of sampling (Figure 3-3). Based on
conductance profiles, elevated dissolved solids inflows from McDowell Creek frequently
appear to suffuse into the lake at depths below 3 meters. Elevated summer specific
conductance values observed in the deepest waters of Mountain Island Lake forebay
(Location G) are primarily linked to increased concentrations of the dissolved fraction of
redox -sensitive metals (e.g., reduced iron and manganese), reflective of the influence of
thermal stratification and seasonal anoxia at that particular site.
From a temporal perspective, slightly elevated specific conductance was observed lake -wide
during 2008, with August 2008 values similar to increased conductance levels encountered
during the 1998 — 2002 regional drought. A drought period spanning spring 2007 through
the summer of 2008 likely contributed to the elevated dissolved solids, driving the
conductance readings upward (NCDENR 2009). However, marginally increased Lake
Norman dissolved solids concentrations, linked to a new discharge of flue gas desulfurization
wastewater at Marshall Steam Station on Lake Norman, may also be a contributor to recently
elevated lake -wide conductance values (Duke Energy, unpublished data).
In-situ pH (Figures 3-4 and 3-6) in the main channel of Mountain Island Lake tended to be
circum -neutral, with a median pH of 7.1, and a range of pH 6.1 to 7.9 during 2004 — 2008. A
general increase in reservoir -wide pH, and to some extent, total alkalinity (see discussion
below; Figure 3-7) is apparent over the 19 years of monitoring summarized in this report.
These gradual increases may be related to slight increases in calcium (Figure 3-15) as well as
decreases in sulfate concentrations (Figure 3-20) over a similar time period. While added
3-4

calcium inputs are likely attributable to increased Mountain Island Lake and Catawba River
Basin watershed development over the past two decades, similarly timed reductions in
sulfate concentrations in Southeastern surface waters have been observed. These sulfate
reductions are thought to be related to lower sulfate deposition attributable to air emissions
control measures implemented at numerous up -wind coal -electric generating facilities
(USEPA 2003).
Surface (0.3 m) pH values ranged from 6.6 to 7.9 lake -wide. Lowest pH values were
observed during the August 2005 sampling. Drought -associated summer 2007, and
particularly 2008 pH values in the McDowell Creek cove (Location D) ranged from 7.5 to
7.9, displaying a tendency toward slightly more alkaline conditions compared to other lake -
wide sample locations. Likewise, forebay (Location G) euphotic zone (e.g., depths < 3 m)
pH values were marginally more alkaline (pH 7.4 to 7.8) in August 2008 than the earlier
2004 — 2007 samplings. These forebay pH values were coincident with slightly
supersaturated dissolved oxygen concentrations (e.g., 109 to 111%) measured at 0.3 to 3 m
depth and were probably linked to increased densities of phytoplankton and resultant
photosynthetic activity occurring due to the warm and relatively dry weeks prior to the
August 20 sampling date (NOAA 2008b).
Total alkalinity as CaCO3 ranged from 12 to a maximum of 60 mg/L (the latter value from a
forebay bottom sample in 2008) during 2004 — 2008 (Figure 3-7). Greatest alkalinity
concentrations lake -wide were measured during the August 5, 2004 sampling, ranging from
23 to 29 mg CaCO3/L. From a spatial perspective, total alkalinity values associated with the
McDowell Creek cove (ranging from 12 to 29 mg CaCO3/L) were usually slightly elevated
with respect to surface (0.3 m) samples collected from other Mountain Island Lake locations.
As discussed above, total alkalinity concentrations have displayed a long-term, but very
slight increasing trend over the years of this monitoring program. While some of the noted
increase is undoubtedly linked to drought conditions prevalent during several of the years
over the past decade, other watershed -linked contributions may also be important, given the
dynamic changes in land use and population over time.
Mountain Island Lake turbidity ranged from 1.6 to 16.5 NTU in 2004 — 2008 (Figure 3-8).
No samples exceeded the applicable state water quality standard (25 NTU; NCDENR
2007a). Reservoir -wide, turbidity was slightly less spatially variable, compared to prior
reporting periods. Total suspended solids (TSS) concentrations were also generally low
(ranging from 1 to 10 mg/L for mainstem locations) during 2004 — 2008 (Figure 3-9). A
maximum TSS concentration of 16 mg/L occurred in the McDowell Creek arm of Mountain
3-5

_ Island Lake during the February 2007 sampling, a site where greatest TSS concentrations
have frequently been observed in the past (Bales et al. 2001; Duke Power 2001, 2004).
Nutrient concentrations throughout 2004 — 2008 reflected historical trends and were
consistent with formerly documented, time -variable transitions between oligotrophic and
mesotrophic water quality classifications for Mountain Island Lake (USEPA 1975; Weiss
and Kuenzler 1976; Bales et al. 2001; Duke Power 2001; Buetow 2003; NCDENR 2004).
Ammonia -nitrogen (Figure 3-10), nitrate+nitrite (Figure 3-11), and total nitrogen
concentrations (Figure 3-12) were similar to previous years. Maximal ammonia -nitrogen
concentrations were consistently measured during summer in the deeper waters of the MIHS
forebay; Location G (maximum of 1.3 mg NH3-N/L August 20, 2008). This was the only
sample location where near -bottom samples were obtained in this monitoring program.
Seasonally elevated ammonia -nitrogen concentrations noted for deep samples collected at
this site can be linked to anoxia -induced strongly reducing conditions, which result in an
increased release of nutrients from lake sediments, as well as limitation of oxygen -dependent
microbial nitrification processes. Such seasonal increases in ammonia -nitrogen
concentrations have been reported previously in Mountain Island Lake, and other Catawba
- River reservoirs (Bales et al. 2001; Duke Power 2004). These seasonal increases in the
reservoir hypolimnetic ammonia -nitrogen were also reflected in 2004 — 2008 total nitrogen
concentrations.
Lake -wide, phosphorus concentrations were similar to those observed in recent years.
Concentrations of soluble orthophosphate (Figure 3-13) and total phosphorus (Figure 3-14)
in the McDowell Creek arm of Mountain Island Lake (Location D) have for many years
provided a consistent indication of nutrient loading via the McDowell Creek WWTP. Bales
et al. (2001) observed, based on 1996 — 1997 monitoring, that on average approximately one
half of the loading of total phosphorus to Mountain Island Lake entered the reservoir from
McDowell Creek. Six individual exceedances of the Mecklenburg County Water Quality
Program (MCWQP) action level (0.04 mg/L) for total phosphorus were reported for the
McDowell Creek arm of Mountain Island Lake during 2007, as well as a sample exceeding
the action level in the Gar Creek arm of the lake, during the same drought -impacted year
(Buetow 2008). During 2004 — 2008, both orthophosphate and total phosphorus
concentrations were reduced in the McDowell Creek arm with respect to prior years of
monitoring.
Loading of nutrients to Mountain Island Lake during 2004 — 2008, while reduced overall,
remained evident from spatial trends in nitrate+nitrite (Figure 3-11) and total phosphorus
3-6

(Figure 3-14) concentrations. As for phosphorus, the MCWQP action level for nitrate+nitrite
(0.65 mg/L) was exceeded on three occasions in the McDowell Creek arm of the lake during
2007; no exceedances were observed elsewhere in the reservoir (Buetow 2008). McDowell
Creek was listed as impaired for biological integrity in the most recent (2006) 303(d)
evaluation of state water quality use attainment (NCDENR 2007b). Continuing nutrient
enrichment and excessive solids loading from the McDowell Creek WWTP and the
extensively developed catchment further upstream undoubtedly contribute to this
impairment.
During 2004 — 2008, concentrations of major cations, including calcium (Figure 3-15),
magnesium (Figure 3-16), sodium (Figure 3-17), and potassium (Figure 3-18); and anions,
including chloride (Figure 3-19) and sulfate (Figure 3-20) were generally consistent with
previous trends. Median concentrations of these major dissolved ionic constituents, as for
specific conductance (Figure 3-5), were slightly lower than the marginally elevated
concentrations observed during the prolonged 1998 — 2002 regional drought. As discussed
previously for calcium, long-term temporal trending appears to also indicate a slight increase
in magnesium concentrations over the years 1990 — 2008, whereas sulfate concentrations
appear to be in slight decline over the same timeframe.
Mountain Island Lake iron (Figure 3-21) and manganese (Figure 3-22) concentrations during
2004 — 2008 were typical of previous years. Surface concentrations of the two metals
remained low and showed minimal variation among the locations. However, as is commonly
observed, substantially elevated summertime iron and manganese concentrations in the
minimally oxygenated water near the lake bottom at the forebay location (G) were evident, as
expressed by maxima on Figures 3-21 and 3-22 (note log concentration scale).
Aluminum concentrations (Figure 3-23) have, over time, displayed a clear decreasing trend.
It is possible, although presently unconfirmed for this site, that the observed decreases in
aluminum may be linked to reduced regional atmospheric sulfate deposition and lessened
watershed acidification over recent years, due to the increasing implementation of coal-fired
power plant emission controls. Similar aluminum concentration reductions have been
demonstrated in northeastern U.S. lakes in response to power plants air emission controls and
reduced acid deposition of sulfur (Warby et al. 2008).
Soluble silica concentrations (Figure 3-24) were comparable to long-term monitoring data.
Median silica concentrations were marginally greater in the McDowell Creek cove (Location
D) and further down -lake mainstem sites (Locations E and G) relative to further up -lake.
3-7

Aqueous concentrations of trace elements were typically near or below laboratory reporting
limits during 2004 — 2008. No spatial trends were evident in the lake -wide trace element
concentrations, with the exception that samples collected from the lake bottom at the MIHS
forebay (Location G) yielded 2004 — 2008 maximum concentrations of total recoverable
arsenic (maximum of 11.4 gg/L August 20, 2008; Figure 3-25) and barium (maximum of
0.14 mg/L; Figure 3-26). A maximum total recoverable copper concentration of 5.49 µg2
was measured at surface (0.3 m) at the forebay location (G) August 5, 2004 (Figure 3-27).
Of these three trace elements, only a single August 2008 lake forebay (Location G) bottom
sample exceeded a state water quality standard (arsenic; 10 gg/L based on human health) or
action level (NCDENR 2007a). Total recoverable cadmium, chromium, lead, nickel, silver,
and selenium concentrations consistently remained below method reporting limits (Table 3-
1) and applicable water quality standards or action levels throughout 2004 — 2008, and are
not depicted graphically. Two mercury samples exceeded laboratory reporting limits during
2004 — 2008. Mercury in a sample collected August 5, 2004 from the lake mainstem at the
CMUD water intake (Location E) had a concentration of 0.35 µg/L, and a second sample
collected August 4, 2005 from the bottom at the MIHS forebay (Location G) yielded a
concentration of 0.32 gg/L. The cause of this pair of elevated mercury concentrations, which
exceeded water quality standard of 0.12 gg/L, was undetermined (NCDENR 2007a).
RSS Ash Basin Effluent Selenium and Arsenic Mass Loading Estimates
For the five-year period, 2004 — 2008, loading of arsenic (Figure 3-31) from the NPDES-
permitted RSS ash basin discharge averaged 895 g/day, and selenium loading (Figure 3-32)
averaged 47.5 g/day. As described previously (Duke Power 2001), the post -1995 estimated
increase in arsenic or selenium 'loading, depicted in Figures 3-31 and 3-32, should be
considered artifacts of modified discharge flow calculations implemented in 1995, rather
than being attributed to any operational changes at RSS.
Estimates of arsenic mass loading to Mountain Island Lake were near or below historical
averages, ranging from 336 g/day (2007) to 1,556 g/day (2006). Arsenic loading increased
approximately two -fold over the years 2004 — 2006, after a minimum level of loading was
achieved in 2003. Subsequently in 2007 and 2008, loading was substantially reduced to
levels not observed in recent years. Arsenic loading reductions in 2003 were in part linked to
significantly greater precipitation event -driven watershed contributions to the ash pond
(Duke Power 2004). Reductions in effluent arsenic concentrations driving the 2007 — 2008
3-8

loading estimates lower, however, may be related to changes in coal supply, as the reductions
show no clear linkage with RSS coal-fired electric generation capacity (Table 2-1).
Mass loading of selenium via the RSS ash basin outfall displayed somewhat less inter -annual
variability, in contrast to arsenic. Annual average selenium loading ranged from 36 g/day
(2004) to 56 g/day (2006). As observed previously, selenium loading from the ash pond
effluent appeared more closely linked to effluent discharge rates than did arsenic loading
rates (Duke Power 2001, 2004). Mean annual Se concentrations in ash pond effluents during
2004 — 2008 were only marginally above the laboratory reporting limit, ranging from 2.3 to
3.1 µg/L.
Sediment Elemental Anal
Neutron activation analysis of surficial fine (< 63 µm; silt+clay fraction) Mountain Island
Lake sediments sampled March 6, 2008 resulted in arsenic concentrations of similar
magnitude as observed previously at the two sites upstream of the RSS ash basin discharge
(Locations A and B), but increased arsenic concentrations down -lake (Locations C and G),
compared to previous years (Figure 3-33). Arsenic results for sediments collected
immediately downstream of the RSS ash basin discharge (Location C) were particularly
elevated in 2008 with respect to historical data, with a median arsenic concentration of 77.7
µg/g, i.e., more than three -fold the median 2004 arsenic concentration (see following
discussion). Results of Kruskal-Wallis tests showed that for all 1988 — 2008 sediment
samples combined, sample location had a highly significant effect (P < 0.001) on the
magnitude of arsenic concentrations in sediment fines. For 2008 samples, Wilcoxon rank
sum scores indicated arsenic concentrations in fine surficial sediments collected at the two
sites downstream of the RSS ash basin outfall were significantly (Location C: P < 0.001;
Location G: P < 0.01) greater than up -lake concentrations.
Atypically elevated sediment arsenic concentrations from Location C, immediately
downstream of the RSS ash basin outfall are thought to be an artifact of a slight change in the
sampling site in 2008. Sediments sampled from the customary sites within the river channel
in recent years have been exposed to substantial currents during upstream CFHS generation,
so that samples frequently yield primarily coarse sand (virtually no fines present). This was
particularly the case at Location C in 2008. To facilitate collection of sediment fines, an area
was sampled approximately 250 in upstream, very near to the mouth of a cove where RSS
ash pond effluent flows into the lake. Presumably, over the years, relatively arsenic -rich ash
pond effluent -associated particulates have settled in this cove, including the region sampled
3-9

near the point of confluence with the river channel. Therefore, the 2008 Location C samples
may be considered largely indicative of material entering the mainstem from the cove
impacted by RSS ash basin effluents, rather than indicative of the mainstem of the lake itself
(where deposits of sediment fines were virtually absent in 2008).
The scarcity of sediment fines in the river channel at Location C is linked, conversely, to the
gradual increases observed in sediment arsenic concentrations at the Mountain Island Lake
forebay (Location G). Lower velocities encountered in this deepest portion of the lake
facilitate an ultimate sink for fine particulates. Location G trace element analyses therefore
serve to provide a window on the long-term arsenic mass loading from all upstream sources,
including the RSS ash basin outfall.
Similar to the 2004 sampling, sediment selenium concentrations (Figure 3-34) from samples
collected in 2008 were mostly below sample -specific detection limits (i.e., 33 of 40 samples),
so statistical methods were not employed for this analyte. (Selenium concentrations less than
detection limits were represented graphically as the detection limit in Figure 3-34.) No
overall location -dependent relationship was apparent in the combined set of 1988 — 2008
samples for selenium. This observation is consistent with the relatively low concentrations
of selenium typical of the RSS ash basin discharge.
CONCLUSIONS
Water quality in Mountain Island Lake during 2004 — 2008 was similar to previous years.
Seasonal thermal stratification, dissolved oxygen concentrations, and pH were representative
of historical ranges. Specific conductance values had increased by the end of the monitoring
period in 2008, achieving values similar to those recorded during the drought earlier in the
decade. Lake -wide, concentrations of major nutrients, similar to historical levels, indicated
spatial variability, but continued to result in Mountain Island Lake being classified as
oligotrophic to mesotrophic during 2004 — 2008. Typically elevated concentrations of
dissolved and suspended material, as well as nutrients entering the lake from the McDowell
Creek drainage, were slightly lessened during 2004 — 2008. This impaired tributary,
however, continued to produce a localized degradation of water quality, typically limited to
the McDowell Creek cove of the lake. Mass loading of selenium and arsenic from the RSS
ash basin outfall during 2004 — 2008 was similar to historical trends, except for reductions
observed in arsenic loading over the 2007 — 2008 period. Mountain Island Lake
concentrations of aqueous trace elements remained generally low, consistent with low levels
3-10

of turbidity and suspended solids. One sample (total recoverable arsenic of 11.4 µg/L,
collected in August 2008) yielded the singular exceedance of a state water quality standard or
action level for trace elements during 2004 — 2008.
March 2008 arsenic concentrations in fine surficial sediments were elevated downstream of
RSS with respect to uplake concentrations, with samples just downstream of the RSS ash
basin effluent confluence yielding the highest concentrations. While the 2008 samples were
likely influenced by a slight relocation of the sampling site due to difficulty in obtaining
material other than coarse sand at the former location, MIHS forebay sediment sampling
continues to indicate a slight, gradual increase in arsenic concentrations over recent years.
Sediment concentrations of selenium were consistently low lake -wide. As a whole, 2004 —
2008 Mountain Island Lake water and sediment chemistry continue to indicate the waterbody
remains capable of sustaining balanced and indigenous aquatic communities. Trace element
concentrations measured in Mountain Island Lake common carp, sunfish, and largemouth
bass since 1988 remain well below values of regulatory concern (Chapter 5).
3-11

Table 3-1. Analytical methods used to determine chemical and physical constituents in
Mountain Island Lake during 2004 — 2008.
Parameter
Method (EPA/APHA)3
Preservation
Reporting Limit
Alkalinity, Total
Total inflection point titration
4'C
0.01 meq/L
EPA 310 1
as CaCO3
Aluminum
Atomic emission/ICP
0 5% HNO3
0 05 mg/L
EPA 200.7
Arsenic, Total
ICP Mass Spectrometry
0 5% HNO3
2 0 pg/L
Recoverable
EPA 200.8
1 0 pg/L4
Arsenic, Sediment
Neutron Activation Analysis
4 °C
0 0002 pg/g
Barium Atomic emission/ICP
EPA 200.7
Cadmium, Total ICP Mass Spectrometry
Recoverable EPA 200.8
Calcium Atomic emission/ICP
EPA 200 7
Carbon, Total Organic EPA 415.1
Chloride
Conductance,
Specific
Chromium, Total
Recoverable
Copper, Dissolved
Copper, Total
Recoverable
Iron, Total
Recoverable
Lead, Total
Recoverable
Magnesium
Ion Chromatography
EPA 300 0
Temperature -compensated
nickel or graphite electrode
APHA 2510
ICP Mass Spectrometry
EPA 200 8
ICP Mass Spectrometry
EPA 200.8
ICP Mass Spectrometry
EPA 200.8
Atomic emission/ICP
EPA 200.7
ICP Mass Spectrometry
EPA 200 8
Atomic emission/ICP
EPA 200.7
0 5% HNO3
0 5% HNO3
0 5% HNO3
4 °C,
0 5% H2SO4
4 °C
in-situ
0 5% HNO3
0 5% HNO3
0 5% HNO3
0 5% HNO3
0.5% HNO3
0 5% HNO3
3 References 1 USEPA 1983 2. APHA et al. 1998
4 August 2008 only
5 Optimal conditions, no interfering elements in sample matrix
6 Instrument sensitivity furnished in lieu of laboratory reporting limit
sample
0 005 mg/L
0 5 pg/L
1 0 pg/L4
0 03 mg/L
0 1 mg/L
10 mg/L
0 1 pS/cm6
1 0 pg/L
2 0 pg/L
1 0 pg/L4
2 0 pg/L
1 0 pg/L4
0.01 mg/L
2.0 pg/L
0.03 mg/L
3-12

Table 3-1. (Continued).
Parameter
Method (EPA/APHA)
Preservation
Reporting Limit
Manganese
ICP Mass Spectrometry
0 5% HNO3
1.0 pg/L
EPA 200 8
Nitrogen, Ammonia
EPA 350 1
40C
0 02 mg/L
0 5% H2SO4
Nitrogen, Nitrate+Nitnte EPA 353 2
40C
0 02 mg/L
0 5% H2SO4
Nitrogen, Total
EPA 351 2
40C
0.1 mg/L
Kjeldahl
0 5% H2SO4
Nickel
ICP Mass Spectrometry
0 5% HNO3
2 0 pg/L
EPA 200 8
Phosphorus,
EPA 365 1
4 °C
0 005 mg/L
Orthophosphate
Phosphorus, Total
EPA 365 1
40C
0 01 mg/L
0 5% H2SO4
Oxygen, Dissolved
Temperature -compensated
in-situ
0 01 mg/L6
polarographic cell
APHA 4500-0-G
pH
Temperature -compensated
in-situ
0 01 units
glass electrode
APHA 4500-H+
Potassium
Atomic emission/ICP
0 5% HNO3
0 25 mg/L
EPA 200.7
Selenium
ICP Mass Spectrometry
0 5% HNO3
2.0 pg/L
EPA 200.8
1 0 pg/L4
Selenium, Sediment
Neutron Activation Analysis
40C
0 02 pg/g sample
Silica (as Si)
APHA 4500Si-F
40C
0 5 mg/L
Silver
ICP Mass Spectrometry
0 5% HNO3
0.5 pg/L
1 0 pg/L4
EPA 200 8
Sodium
Atomic emission/ICP
0 5% HNO3
1.5 mg/L
EPA 200 7
Solids, Total
Gravimetric, dried at 103-105 °C
4 °C
20 mg/L
EPA 160 3
12 mg/L'
Solids, Total
Gravimetnc, dried at 103-105 °C
4 °C
0 10 mg/L
Suspended
EPA 160 2 / APHA 2540 D
Sulfate
Ion Chromatography
40C
1 0 mg/L
EPA 300 0
' August 2005; 2006 samples
8 Modified Seston method for 1-L samples
3-13

Table 3-1. (Continued).
Parameter Method (EPA/APHA) Preservation Reporting Limit
Temperature NTC Thermistor in-situ 0 01 °C6
APHA 2550
Turbidity Turbidimetric 4 °C 0 05 NTU
EPA 180 1
Zinc ICP Mass Spectrometry 0 5% HNO3 1 0 pg/L
EPA 200 8
3-14

2004 2005
0 5 10 15 20 0 5 10 15 20
0
5
E
L 10
CL
0)
❑
15
20
0
0
5
L 10
Q
a�
15
20
2006 2007
5 10 15 20 0 5 10
2008
0 5 10 15 20
0
5
15 20
Z 10
0.
0)
15
20
Figure 3-1. Winter (February) profiles of temperature (°C; ■) and dissolved oxygen (mg/L;
❑) at the Mountain Island Lake forebay, Location G.
3-15

E
E
2004
0 5 10 15 20 25 30 35
0
5
15
2005
0 5 10 15 20 25 30 35
0
20
2006
0 5 10 15 20 25 30 35
0
5
15
20
E
2007
0 5 10 15 20 25 30 35
0
5
L 10
a
CD
1s
20
2008
0 5 10 15 20 25 30 35
0
5
L 10
Q
0)
15
20 '
Figure 3-2. Summer (August) profiles of temperature (°C; ■) and dissolved oxygen (mg/L;
❑) at the Mountain Island Lake forebay, Location G.
3-16

Location A
µS/cm
0 25 50 75 100 125 150 1i5 200 225 250
0
2
3
4
L 5
CL
6
7
8
9
Location C
µS/cm
0 25 so 75 100 125 150 '175 200 225 250
0
P 9
S Feb 2004
__�--Aug 2004
4 Feb 2005
2 _ _—o-�Aug2005
Feb 2006
.vAug2006
8 - _ - - - Feb 2007
—f'Aug2007
+ Feb 2008
`� •
Aug 20081
CL e
N
0 6 - _ _ _ _ _ _ _
g- - - _ _ _ _ - _ _ x
Location E
µS/cm
0 25 50 75 100 125 150 175 200 225 250
0
• o F 211
7 - b� Aug 2004
Feb2005
2a • a d n= n Aug 2005
Feb 2006
3 �- s>4_ - Aug 2006
E 4
L 5
O.
(1) s
7
8
9
1n
Location B
µS/cm
0 25 50 75 100 125 150 175 200 225 250
0 }
o Fe62004
1 _—_-- -4 - ____________ _ __ —0_Aug 2004
c= Feb 2005
2 • s -Aug 2005
o Feb 2006
3 —_—_ y _ _ _ _ _ _ _ _ _ _ Aug 2006
Feb 2007
- Q *:' _nE�-- o _ _ —~Aug 2007
4
} + Feb 2008
Aug008
5
Q
N ❑ _
8
Location D
µS/cm
0 25 50 75 100 125 150 175 200 225 250
0
■
o Feb 2004
-
4 Feb2005
2 —Aug 2005 _Q_ __ __ _--_ _ _ _ _
F.b2006
3 Aug 2006
E 4
L 5
Q
N
� 6
7
8
9
10
Location G
µS/cm
0 26 50 75 1100 125 150 175 200 225 250
0
5
E
t 10
n
a�
15
20
Figure 3-3. Semi-annual specific conductance profiles in Mountain Island Lake, 2004 —
2008.
3-17
•
o Feb 2004
♦
�- Aug 2004
♦
F.b2005
Aug 2005
Aug 2006
♦
• Feb2007
Aug 2007
Qi
♦
+ Feb 2008
1-�
Aug 2008
a
4
a
.
_
Figure 3-3. Semi-annual specific conductance profiles in Mountain Island Lake, 2004 —
2008.
3-17

Location A
pH SU
6 7 8
Location B
pH SU
9 5 6 7 8 9
5
0
1
3
E 4
L 5
CL
Q)
Q 6
7
8
9
10
0-
1
2
3
E 4
t 5
a
CU
0 6
7
8
9
.. ... .. ... .. ... ... ... .. ...........
o Feb 2004
--_----_ _ _ _ _ _ _ f _ _ _ _
o 1- 21-
-o-Aug 2004
d Feb2005
♦ *
=--�-Aug 20041
- - ---- - �Y- af-
•
Aug 2005
o Feb 200
e Feb 2005
_
• Feb 2007
A
-a- Aug 2005
- - - « • t -
a Feb2008
� Aug 2006
a Feb 2008
0
�- Au 208
POOP
070 •�
�.� Aug 20081
-Aug 208
_'�.. _
d] 4•
• Feb 2007
_ _ _ _ _ _ _ _ _ _
d 04•
n. so
Aug 2007
l ■
o
+ Feb 20081
t A 2008
-- - --- - - -- --
9da
y♦
_
d
°la
i
5
0
1
3
E 4
L 5
CL
Q)
Q 6
7
8
9
10
0-
1
2
3
E 4
t 5
a
CU
0 6
7
8
9
.. ... .. ... .. ... ... ... .. ...........
o Feb 2004
--_----_ _ _ _ _ _ _ f _ _ _ _
_ . Aug 2004
-o-Aug 2004
d Feb2005
♦ *
-o-Aug 2005
- - ---- - �Y- af-
o Fe6200
Aug 2005
o Feb 200
Aug 2006
_
• Feb 2007
A
-f-Aug 2007
- - - « • t -
a Feb2008
� Aug 2006
-r Aug2008
0
�- Au 208
Location C
pH SU
6 7 8 9 5
•
o Feb 2004
_ _ _ _.� -_ _ _ _ • >=o— Aug 2004
e Feb 200$
- - - • —� Aug 2005
• o Feb200
____________ ��• Aug 2006
- - - - - - I Feb 2007
1 207
a • Feb 2008
•
O • • Aug206
- - - - - - - - -- - - _
Location E
pH SU
3
E 4
L 5
CL
6
7
8
Location D
pH SU
6 7 8 9
Location G
pH SU
5 6 7 8 9 5 6 7
0
2
3
4
t 5
d
Q 6
7
8
9
10
0
5
t 10
d
15
20
8 9
0 Feb2004
_--__ __ _ _ 1 ♦R
-
-o-Aug 2004
Imo --Aug 204
a Feb2005
- - ---- - �Y- af-
o- Feb 2005
Aug 2005
o Feb 200
-___-----_-_ _ _ _ _ 6 _ _ -
_
� Aug 206
A
o Feb 200 _
• Feb 2007
�Aug207
� Aug 2006
Feb 208
------------------------------------
�- Au 208
Location G
pH SU
5 6 7 8 9 5 6 7
0
2
3
4
t 5
d
Q 6
7
8
9
10
0
5
t 10
d
15
20
8 9
Figure 3-4. Semi-annual pH profiles in Mountain Island Lake, 2004 — 2008.
3-18
D �•
0 Feb2004
a •
Imo --Aug 204
d ♦
o- Feb 2005
p
-o-- Aug 2005
o Feb 200 _
m -
� Aug 2006
P ♦
4CO
■ Feb207
-Aug207
• Feb2008
POOP
070 •�
-Aug 208
_'�.. _
d] 4•
c0411
d 04•
e0� 1
l ■
Figure 3-4. Semi-annual pH profiles in Mountain Island Lake, 2004 — 2008.
3-18

250
200
150
E
Cn
100
50
O
---
—
---
—
-
-
-
--
------
----
IL&
----
-----
-- -
1
N (V
N N
N N
N N
N N
O O
m
N O
O No
_
N N
N N
m
N N
O O
A
B
c
D
E
G
Sample Dates / Location
Figure 3-5. Distribution of Mountain Island Lake specific conductance.
5
N pN o _O gN N O O N O O O
O O O O Q O $ O O O O G O o o � O O O
N N N N N N In N
A B C D E G
Sample Dates / Location
Figure 3-6. Distribution of Mountain Island Lake pH.
70
so
50
40
O
U
Lj

50= -
i ! ! i i ! ! i- i i T i"' T= T i i i I
45 - r- r - � i r --�-� r F-- =r +-� - - a - r r- t - � + --� - r - _t=r -� _•_-, r
1 ! ! 1 ! ! f f ! !
� _
35 t G I�=, __ gl I ! { l + I Jv l I G
r I— i a r t �— f I f— 1 �� t——r T=r�� VI——c t
~ 25 - ---- f - - - ---- -- - -- - -- - -- --- - -------=
Z'20 -1- ----- I -------I ------ T --- - - ------ -------1 ------4------ ------ -- -I ------ ------a-- ---- -----1------
15
----15 --f -- 1 + f - f- 1 1- t 7- f i I- � t- - , Y- -- f -- --f- - - - -----
10=a
` IID Tja- T�jr �I
5 41i `Y
0
0 0 0 0 0 0 0 o o g o 0
A B C D E G
Sample Dates / Location
Figure 3-8 Distribution of Mountain Island Lake turbidity
80 T r i-
i i l
70 r 1 r Fr - sA r r r r i
so = ---- - ---=- - - = L----- -' y-- --- = --- --- --
50
40 ! ! ! ------
. !------
r----- -*--- - t - - --------r- - - r ----r-- - -r- -- -r r -----T �- r- -- r - --*--- -r---- -- - -- -- r -- -� r --i
20 I I ----- ! -} i + -I-- ---I ! --4 J- -J T- I-- I------1
10
o - -
M M
0
A B c D E, G
Sample Dates / Location
Figure 3-9 Distribution of Mountain island Lake total suspended solids concentrations.
-T=
i-
E, -' -
01
I 1 —; t t 1 1 t r I t t jjj I
�il I ii I SI I I ISI I I I—� i t iii I I Ill
O O O 00
o O O o O O O N
o O o N O N o O N N O O
A B
Sample Dates / Location
Figure 3-10 Distribution of Mountain Island Lake ammonia nitrogen concentrations
3-20

r i I i i i g i I i i
I i i i I i i i i i i
2,5 --- ---------+ ------
- a 1
1-
I i I I i I
2,0 i i
{ !- i- 1 4 r I -_ ! 1 � 4 =_-_= t- s l 1 + 4 =l l-- -��.- --=..i a
ILL
I I I I I I I i I I i I I I I ! I I
1 5 - - r--- -�- " - r ---- r r - r- -- r - -r ---+-- ---t- - r ----r- r -- --r- --- r- --- +---- -r- -- -- ---'-r -- � ` r------ r- -r -i
1 1 1 1 1 1 1 1 1 1 I I I I I
1 O ...... i i I t i t i Y 1-
I I I! I I I�I
O 5 --'-----' -
00
A B G D E G
Sample Dates / Location
Figure 3-12 Distribution of Mountain Island Lake total nitrogen concentrations
007
O 06�- _ i 7 1 1 1
�' - � i ..•`�- `�1 - I I i i i i - i i
- 4005 -----+---- - -- --- ----- - -- i --
i
` i (
� O 04 -� -----� -- --�------�----- T - =T- --- T-- ---I- ---{-------{--- --T -----'�------T-- -T- --- �- ' -;-- -- }- --------- T-- --- I--` f --- --- ---- -- ----i
003 E f =- 4{+ I +- -{ T i f f j` 0., - T- --A
rf
002
001 -
�-� r
000
o O Q O o O O o o O o Q O o
O N O o N N O O O o o N
A, B C D E, G
Sample Dates / Location
Figure 3-13 Distribution of Mountain Island Lake soluble orthophosphate concentrations
3-21
T I
T—
1
�.,6
q
---- - ---- - -- --- ---- ------
i - I
j
----------'-- - - - --- ---- - -------=-- ---
i f- t- I i
�- � �
I
- -- ------
t-' r- I I
I I
- -- --- --
i t- i
� j---�
1 2
�
----`------
-- ----- - ------ -- --,-------
---;
-- ;
0 8
-fI ----- - 1-------
t ----- I� If - 1- 1i - ti fI
�-
I i i
- i
i i i
06
I
1----
0,4
02�}}r
I I i
t t T
�7r-rS}t�+�I
i i
i I I i I
j I Y t' 1 1 i 7
I
Y
I I I
i I
T i i
I
O.0
o N
o o O o
O O o 0
0 0
A
B C
D E
G
Sample Dates / Location
Figure 3-11
Distribution
of Mountain Island Lake nitrate+nitrite nitrogen concentrations
r i I i i i g i I i i
I i i i I i i i i i i
2,5 --- ---------+ ------
- a 1
1-
I i I I i I
2,0 i i
{ !- i- 1 4 r I -_ ! 1 � 4 =_-_= t- s l 1 + 4 =l l-- -��.- --=..i a
ILL
I I I I I I I i I I i I I I I ! I I
1 5 - - r--- -�- " - r ---- r r - r- -- r - -r ---+-- ---t- - r ----r- r -- --r- --- r- --- +---- -r- -- -- ---'-r -- � ` r------ r- -r -i
1 1 1 1 1 1 1 1 1 1 I I I I I
1 O ...... i i I t i t i Y 1-
I I I! I I I�I
O 5 --'-----' -
00
A B G D E G
Sample Dates / Location
Figure 3-12 Distribution of Mountain Island Lake total nitrogen concentrations
007
O 06�- _ i 7 1 1 1
�' - � i ..•`�- `�1 - I I i i i i - i i
- 4005 -----+---- - -- --- ----- - -- i --
i
` i (
� O 04 -� -----� -- --�------�----- T - =T- --- T-- ---I- ---{-------{--- --T -----'�------T-- -T- --- �- ' -;-- -- }- --------- T-- --- I--` f --- --- ---- -- ----i
003 E f =- 4{+ I +- -{ T i f f j` 0., - T- --A
rf
002
001 -
�-� r
000
o O Q O o O O o o O o Q O o
O N O o N N O O O o o N
A, B C D E, G
Sample Dates / Location
Figure 3-13 Distribution of Mountain Island Lake soluble orthophosphate concentrations
3-21

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--�----- I I
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12 --T -- - --- --- 7 -1 ----- -- T- -- - ----- -- ------- ---- -- -
10
1 1 T 'T 1 t -1 i
f - t
4
2
0
e
93 M 8 8
- -- - - - - - - - - -- - -
A B C D E G
Sample Dates / Location
Figure 3-17 Distribution Of Mountain Island Lake sodium concentrations.
3 5 - -- ---- ----- - -------
3 0-' - ------- - - -- --- -----------
1----T -T-
2,5
20
E
'11 5 J
1 0 ------
-------- ----------- --
05 t------I-------� ------+-4- -- ---i------{------=-------t------ 4 ------- --------- --- 4--- --a- - ---- ! ------ ------t ------- -- ----i------a
0,0
iE3 2 M M 2 0 P2
C�
93 8
A B c D E G
Sample [Dates Location
Figure, 3-18 Distribution of Mountain Island Lake potassium concentrations
16 -
- --------- - -- ------T--- --T --T -----T---- --- --- -------------- -- ---- ---T-------r- ----T -T-- -7
---- T ----- 7 ----
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Figure') -19. Distribution of Mountain Island Lake chloride concentrations.
3-23

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A B C D EI G
Sample Dates / Location
Figure 3-26 Distribution of Mountain Island ,Lake barium concentrations
-'------ --- - ----T -------- •-
10
i ry I i i i i i 1 i �I E I 1 i
i i I I I i I I
8 m - 1 j +..... .-- -- i.w= i f - w —+ j
i i i i i i i i I I i i i I i i
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i i i i I I I I I i i I i i I
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A B CD E G
Sample Dates / Location
Figure 3-27. Distribution of Mountain Island Lake copper concentrations
12 •- --r----- -- --- _ ------•----- - --- -- I r - --r -- - r -- --I
Oma 6 4 k � k JH --L-
1 = t { h i I _.• qs .+- I
, I I
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N o O O O O O o O
o V(T O O o o O O O O O O O
A B C D E G
Sample Dates / Location
Figure 3-28. Distribution of Mountain [bland Lake soluble copper concentrations
,3-26

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cl Discharge Flow
■ As Loading
-------------- ------------------ ---- ----------------------- ---- ---------------------------------------------- ---- ---------
-- -- -- - -- - -- -- - -- - - -- -- -
1,800
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D
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M O M O O O W O O O O O O O O O O
O 07 D7 O O O O O O O O O O O O O O
N N N N N N N N
Figure 3-31. Average annual RSS ash basin discharge and arsenic loading to Mountain
Island Lake, 1992 — 2008.
25.000
a
CU
a 20,000
.E
a�
a' 15,000
10,000
a
CO
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O O O O M M O O O O O O O O O O O
O Q) Q7 O d1 O O O O O O O O O O O O
r c- r- c- N N N N N N N N N
Figure 3-32. Average annual RSS ash basin discharge and selenium loading to Mountain
Island Lake, 1992 — 2008.
3-28
11 Discharge Flow
-------------------------- ------------ ---------------- -----------------------
--------------------------------- -- --
-- -- -- -- -- -
-- -- -- -- -- --
■ Se Loading
-----------------------------
- -- -- -- --
- - -- -- --
-- -- -- -- --
---------- ------------
-- --
- -- --
-- -- --
----
--
--
--
---------
-
-
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m
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CD
40 r-
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v
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20
10
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N CO IT to (0 r— 00 O ON M I- LO M r— CO
O O O O M M O O O O O O O O O O O
O Q) Q7 O d1 O O O O O O O O O O O O
r c- r- c- N N N N N N N N N
Figure 3-32. Average annual RSS ash basin discharge and selenium loading to Mountain
Island Lake, 1992 — 2008.
3-28

100-T-- -� - �-�- -�- - �- r ---r---
T—T-
I I(( I l l l j l l l l l l(( l l l l
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N N N N N N N N
A(4 8 km US) B (0 5 km US) C (0 6 km DS) G (10 1 km DS)
Sample Dates / Location
Figure 3-33. Distribution of arsenic concentrations in sediment fines sampled from
Mountain Island Lake upstream (US) and downstream (DS) of the RSS ash
basin outfall.
40 T-
i ! �-_i T.T - ; j -
i -i 1 1 1-; 1-!
I j i i i ii l i i i i i l l i i i i
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2 2 N N m n N N T T T T N N 62 Q2 T N N
A(4 8 km US) B (0 5 km US) C (0 6 km DS) G (10 1 km DS)
Sample Dates / Location
Figure 3-34. Distribution of selenium concentrations in sediment fines sampled from
Mountain Island Lake upstream (US) and downstream (DS) of the RSS ash
basin outfall.
3-29

CHAPTER 4
MACROINVERTEBRATES
MATERIALS AND METHODS
Benthic macroinvertebrate sampling was conducted annually in July 2004 — 2008 as part of
the continuing monitoring program for Riverbend Steam Station (RSS). Samples were
collected from three locations in Mountain Island Lake: Location B, approximately 8.5 km
upstream of RSS, Location F adjacent to the RSS discharge, and Location G approximately 3
km downstream of the RSS discharge near Mountain Island Hydroelectric Station (Table 1-1
and Figure 1-1). Note that in past reports (macroinvertebrate chapter only), Location B
(277.6) was incorrectly referred to as Location C (277.5) (Duke Power 2001 and 2004). A
ponar dredge was used to collect five sample replicates at each location. Samples were
collected at depths ranging from 2 — 3 in to bracket the depth of peak benthic abundance
(Brinkhurst 1974). Samples were washed through a 500-µm mesh sieve and individually
preserved with 70% ethanol containing rose bengal stain. Organisms were sorted from the
debris in the laboratory and identified to the lowest practicable taxon. Oligochaeta were not
speciated until after 2001, when they were also identified to species, if possible (Tables 4-1
through 4-3). Macroinvertebrate densities were calculated and recorded. The assessment of
the balanced and indigenous nature of the benthic community was determined by comparing
macroinvertebrate densities and taxa abundance at locations upstream, downstream, and
adjacent to the RSS discharge.
RESULTS AND DISCUSSION
Substrate
The substrate at Locations B (upstream of RSS) and F (RSS discharge) was usually similar,
being composed primarily of silt. The substrate at Location G (downstream of RSS) was
composed mainly of gravel and sand. Other substrate components observed in the samples
included: Naas (aquatic macrophyte), clay, clam shells, and organic matter. These same
components were recorded from location substrates in 2000 — 2003 (Duke Power 2004).
4-1

Density
During 2004 and 2005, densities at Location B were the lowest recorded among locations
sampled, while the density at this Location in 2006 was the highest recorded among locations
that year, as well as the highest recorded for the entire period of 2000 — 2008 (Table 4-1,
Figure 4-1). In 2007, the density at Location B declined once again to the lowest among
locations and then showed an increase in 2008 to the intermediate density among locations.
Densities at Location F showed a sharp decline from the highest spatial value in 2004 to a
comparatively low value in 2005. Densities at Location F increased in 2006 and then
increased again in 2007 to become the highest among locations once again. The density
declined once more in 2008 to the lowest value among locations that year (Table 4-2, Figure
4-1). At Location G, a slight decline occurred from 2004 to 2005, however, the value at
Location G was the highest among locations in 2005. Location G showed a dramatic
increase in density in 2006 to the highest value recorded from this location during 2000 —
2008. Densities at this location declined in 2007 and then increased to the highest among
locations in 2008 (Table 4-3, Figure 4-1). Overall, the long-term average densities from
locations sampled from 2004 — 2008 were higher than those of the previous report period of
2000 — 2003 (Tables 4-1 through 4-3, Figure 4-1).
Taxa Abundance
The number of taxa recorded from macroinvertebrate samples is typically a good indicator of
overall diversity and the presence of balanced indigenous populations. Taxa abundance
showed a slight decrease at all locations between 2004 and 2005, followed by a substantial
increase in taxa numbers in 2006 (Tables 4-1 through 4-3, Figure 4-2). Location G generally
demonstrated the highest taxa numbers among all locations (Table 4-2, Figure 4-2). During
2004 and 2005, taxa abundance was lowest at Location B, and, in 2006, Locations B and G
increased to 36 and 35 taxa, respectively, while 32 taxa were recorded from Location F
(Tables 4-1 through 4-3, Figure 4-2). During 2007, numbers of taxa declined slightly at
Locations B and F (31 taxa each), with a corresponding increase at Location G to 38 taxa, the
highest number recorded at this location during 2004 — 2008. Location B experienced a
substantial increase in taxa from 2007 to 2008, from 31 to 43 taxa, the highest number
recorded from Location B or any other location during 2000 — 2008. Locations F and G
showed declines in taxa numbers over the same period, with the lowest number of taxa
observed at Location F. Long-term average taxa numbers at all locations were higher in
2004 — 2008 than during 2000 — 2003 (Tables 4-1 through 4-3, Figure 4-2).
4-2

Samples were comprised primarily of Oligochaeta, Diptera, and Corbicula. At Location B,
Oligochaeta abundance showed a continuous decline from 2001 — 2005, when less than 50
individuals were observed (Figure 4-3). The density of oligochaetes increased dramatically
at Location B in 2006 and then declined once more in 2007, followed by an increase in 2008.
Oligochaetes dominated densities at Location B in 2007 and 2008. Oligochaetes
demonstrated exceptionally low densities at Location F from 2003 — 2005, then increased
through 2008 to become the dominant group at this location (Figure 4-4). At Location F,
oligochaetes demonstrated a similar temporal trend as that observed at Location G, with
increasing values from 2004 — 2008 when they also became the dominant forms at all three
locations (Figures 4-4 and 4-5).
During 2004 — 2008, Diptera typically showed low relative abundances at Location B, while
they were most often the dominant forms at Location G (Figures 4-3 through 4-5). At
Location F, dipterans were typically more abundant than oligochaetes, but were most often
less numerous than Corbicula (Figure 4-4). Dipteran densities varied at Mountain Island
Lake locations from year to year, showing no consistent long-term patterns.
Corbicula densities and relative abundances were typically lowest at Location G, while the
highest densities were most often recorded from Location F (Figures 4-4 and 4-5). At
Location B, Corbicula densities were low during all but 2006 when Corbicula constituted the
largest proportion of macroinvertebrates recorded (Figure 4-3). No consistent year-to-year
trends were observed among Corbicula populations at Mountain Island Lake locations
during 2004 — 2008.
CONCLUSIONS
Corbicula densities and relative abundances were typically lowest at Location G, while the
highest densities were most often recorded from Location F (Figures 4-4 and 4-5). At
Location B, Corbicula densities were low during all but 2006 when Corbicula constituted the
largest proportion of macroinvertebrates recorded (Figure 4-3). No consistent year-to-year
trends were observed among Corbicula populations at Mountain Island Lake locations
during 2004 — 2008.
4-3

Table 4-1. Densities (number/m2) of macroinvertebrates collected annually from Location B
(upstream of RSS) from 2000 — 2008.
Taxa
2000
2001
2002
2003
2004
2005 2006
2007
2008
Annelida
Hirudinea
Pharyngobdellida
Erpobdellidae
Erpobdella spp
9
Rhynchobdellida
Glossiphonudae
Helobdella spp
26
60
17
26
Oligochaeta
887
1,292
Haplotaxida
Naididae
26
34
9
17
Arcteonats lomondi
17
Dero obtusa
17
Dero vaga
52
Homochaeta naidma
9
26
Naffs communis
34
9
Na►s vanabdis
585
77
267
Ophidonais serpentia
60
Pristina acuminata
9
Pristina longisoma
9
Pristina sima
52
69
Prisbnella osborrn
9
17
Stylana lacustrns
9
9
26
Tubificidae
499
809
448
86
43 2,462
1,128
1,791
Aulodrnlus limnobius
43
121
Aulodrdus pigue6
26
17
17
Branchirua sowerbyi
43
680
353
405
Limnodrnlus spp
138
Limnodrdus hoffineisterei
17
60
121
9
34
Tubifex tubifex
69
Polychaeta
Sabellida
Sabellidae
Manayunkia speciosa
34
241
9
86 284
17
Arthropoda
Acan
17
Crustacea
Amphipoda
Talitndae
Hyalella azteca
878
344
9
Insecta
4-4

Table 4-1. (Continued)
Taxa
2000
2001
2002
2003
2004
2005
2006
2007
2008
Coleoptera
Elmidae
Promores►a spp.
9
Diptera
Ceratopogonidae
Alluaudomyia spp
34
Palpompa-Bezzia complex
86
129
17
17
34
482
95
215
Chaobondae
Chaoborus spp.
9
Chironomidae-Chironommae
Axarus spp
9
112
207
17
Ch►ronomus spp
9
Cladopelma spp
17
Cladotanytarsus spp
9
103
9
Cryptoch►ronmus spp
17
9
43
52
112
77
Cryptotendipes spp
26
146
9
60
9
17
129
189
121
Cryptotendipes emorsus
9
Dem►cryptoch►ronomus cuneatus
9
D►crotendipes spp
9
D►crotendipes neomodestus
9
9
Harn►sch►a spp
52
26
Microch►ronomus spp
9
N►lothauma spp
26
34
Paracladopelma spp.
60
Paralauterborn►ella spp.
9
Paratanytarsus spp
9
Polypeddum spp
9
Polypeddum flavum
9
Polypeddum halterale gp
9
9
9
34
17
9
17
Polypeddum scalaenum
60
Pseudoch►ronomus spp
52
26
9
26
26
293
258
9
129
Saethena spp
60
Stempelhna spp
9
Stenoch►ronomus spp
9
Stictoch►ronomus spp
26
52
60
26
112
112
St►ctoch►ronomus cafiramus
26
86
Tanytarsus spp
138
17
17
26
Chironomidae-Orthocladunae
Cncotopus b►c►nctus
9
Cncotopus pohtus
17
52
Parakieffenella spp
9
17
Chironomidae-Tanypodinae
I
Ej
4-5

Table 4-1. (Continued)
Taxa
2000
2001
2002
2003 2004 2005
2006
2007
2008
Ablabesmpa spp
34
26
301
Ablabesmpa annulata
17
9
17
9
Ablabesmpa janta
26
26
9
9
Ablabesmyia mallochi
34
164
26
9
17
17
43
Cbnotanypus spp.
17
17
17
Cbnotanypus pmguis
60
Coelotanypus spp.
34
103
60
9
52
Djalmabat►sta pulchra
9
9
60
9
Labrundrnia spp
9
Procladius spp
155
258
17
60
138
Procladius bellus
34
Simuludae
Simulium spp
9
Ephemeroptera
Baetidae
9
9
Pseudocentrophlo►des spp
26
Caemdae
Cams spp
9
Ephemendae
Hexagenia spp
9
198
9
103
Odonata-Anisoptera
Corduludae
9
Neurocordulta spp
17
17
Gomphidae
26
9
Gomphus spp
9
Dromogomphus spp
9
Odonata-Zygoptera
Coenagnonidae
17
Argia spp
9
9
Ischnura spp
9
Trichoptera
Hydroptilidae
9
Hydroptda spp
9
17
9
Oxyethira spp
9
Leptocendae
Oecehs spp
26
17
52
9
52
Tnaenodes spp
9
Tnaenodes injusta
9
Polycentropodidae
C rnellus fraternus
17
Polycentropus spp
17
9
9
9
Mollusca
4-6

Table 4-1. (Continued)
Taxa
2000
2001
2002
2003
2004
2005
2006
2007
2008
Gastropoda
Basommatophora
Physidae
Physella spp
9
Pulmonata
Planorbidae
Hehsoma spp.
43
Pelecypoda
Veneroida
Sphaemdae
Pisidium spp.
1,705
Sphaenum spp
43
870
181
155
Heterodontida
Corbiculidae
Corbicula flummea
1,972
164
1,877
611
232
758
4,314
430
1,085
Nematoda
9
43
17
95
43
Nemertea
Enopla
Hoplonemertea
Tetrastemmatidae
Prostoma graecens
86
69
Platyhelminthes
Turbellana
Tncladida
Plananidae
Dugesia spp.
26
284
189
9
Total Density for Year
4,524
5,721
3,816
1,397
1,032
1,645
11,289
3,120
5,402
Total Taxa for Year
35
39
21
14
18
17
36
31
43
4-7

Table 4-2. Densities (number/m2) of macroinvertebrates collected annually from Location F
(RSS discharge) from 2000 — 2008.
Taxa
2000
2001
2002
2003
2004
2005
2006
2007
2008
Annelida
Hirudinea
Rhynchobdellida
Glossiphomidae
Helobdella spp
43
319
9
Oligochaeta
413
327
Haplotaxida
Naididae
17
9
Bratislavia unidentata
9
Dero spp
17
Dero vaga
9
Nais communis
26
17
Naffs vanabdis
69
17
17
Pristina sima
9
9
Prishnella osborm
9
26
9
Stylana lacustris
43
Tubifiadae
276
818
52
232
121
189
Aulodnlus limnobius
17
Aulodnlus piguett
34
276
1,162
Branchirua sowerbyi
52
77
77
129
465
370
224
Polychaeta
Sabellida
Sabellidae
Manayunk►a speciosa
17
155
52
34
Arthropoda
Acan
9
Crustacea
Amphipoda
Talitndae
Hyalella azteca
17
9
9
Decapoda
Palaemonidae
Palaemonetes sp
9
Diptera
Ceratopogonidae
Palpomyia-Bezzia complex
34
17
60
26
26
17
112
43
Chaobondae
Chaoborus spp.
9
17
17
17
9
9
Chironomidae-Chironominae
Axarus spp
17
43
60
Chironomus spp
26
17
17
4-8

Table 4-2. (Continued)
Taxa
2000
2001
2002
2003
2004
2005
2006
2007
2008
Cladopelma spp
9
17
9
9
Cladotanytarsus spp
69
353
112
43
43
164
198
17
Cryptochironmus spp
9
43
26
9
112
43
Cryptotendipes spp
52
112
258
121
9
172
319
215
Demicryptochironomus cuneatus
9
9
Dicrotendipes spp
9
103
26
Dicrotendipes modestus
9
D►crotendlpes neomodestus
17
17
26
17
43
Harmsch►a spp
9
9
9
Microchironomus spp
17
9
Ndothauma spp.
17
34
9
Pagashella spp
60
43
172
52
327
86
17
Parachironomus spp
52
Paracladopelma spp
9
9
Paralauterborniella nigrohalterale
9
9
Polypeddum halterale gp
34
26
17
17
17
69
17
Pseudochironomus spp
17
60
258
69
164
198
353
17
Stempel6na spp
17
26
112
9
Stictoch►ronomus spp
17
26
Stictochironomus cafframus
164
353
17
43
26
Tanytarsus spp
9
9
26
60
17
17
34
52
Thienemann►ella spp
9
Chironomidae-Orthocladunae
Cncotopus pohtus
9
Parakieffenella spp
9
Chi rono m idae-Tanypod inae
Ablabesmpa spp
34
9
34
Ablabesmyo annulata
52
112
138
95
26
17
Ablabesmpajanta
26
9
43
26
Ablabesmyo mallochi
9
9
34
43
Coelotanypus spp
34
224
77
293
138
181
112
86
189
Djalmabatista pulchra
9
9
Proclad►us spp
155
155
69
568
129
60
95
310
293
Procladius bellus
77
Ephemeroptera
Baetidae
9
Caenidae
Cams spp
17
9
17
26
26
207
327
Ephemendae
Hexagema spp
9
86
818
34
551
362
258
482
224
Megaloptera
Sialidae
Sialis spp
9
9
26
9
4-9

Table 4-2. (Continued)
Taxa
2000
2001
2002
2003
2004
2005
2006
2007
2008
Odonata-Arnsoptera
Gomphidae
Gomphus spp.
9
Odonata-Zygoptera
Coenagnomdae
Ischnura spp
9
Trichoptera
Hydroptdidae
Orthotnch►a spp.
34
9
Leptocendae
Oecetis spp
26
9
17
17
17
Tnaenodes spp
9
Polycentropodidae
Cyrnellus fraternus
9
Polycentropus spp.
9
Mollusca
Gastropoda
Basommatophora
Physidae
Physella spp
34
Pelecypoda
Heterodontida
Corbiculidae
Corbicula flummea
310
215
3,0571
629
3,272
430
1,748
3,057
594
Nematoda
26
26
189
198
26
Platyhelminthes
Turbellaria
Tricladida
Planamdae
Duges►a spp.
9
9
Total Density for Year
1,311
1,838
6,217
3,107
5,124
1,8194,867
6,436[!017
Total Taxa for Year
25
32
25
25
27
23
32
31
4-10

Table 4-3. Densities (number/m2) of macroinvertebrates collected annually from Location G
(downstream of RSS) from 2000 — 2008.
Taxa
2000 2001
2002
2003
2004
2005
2006
2007
2008
Annelida
Hirudinea
34
77
Pharyngobdellida
Erpobdellidae
Erpobdella spp
17
Rhynchobdellida
Glossiphonudae
Helobdella spp
86
86
585
293
129
17
OI igochaeta
1,292 1,558
Branchiobdellida
Branchiobdellidae
9
Haplotaxida
Naididae
9
1
26
Allonais pectmata
26
Dero spp
26
Naffs communis
258
26
17
Naffs simplex
112
Nais vanabilis
172
34
827
Pristina longisoma
34
Pristina sima
34
34
103
Prishnella osbomt
17
17
17
Lumbnculida
Lumbnculidae
9
52
Lumbrnculus spp
129
77
198
60
Stylodrdus hermgtanus
9
Tubificidae
1,093
1,042
181
17
422
672
336
1,205
Aulodnlus limnobius
26
Aulodnlus pigueti
17
17
Aulodrdus plunseta
9
Branchirua sowerbyi
69
34
801
577
706
301
293
499
Limnodrdus spp
17
Limnodrnlus hoffineisterei
17
17
Tubifex spp
9
Polychaeta
Sabellida
Sabellidae
Manayunkia speciosa
319
362
Arthropoda
Acan
9
Crustacea
Amphipoda
4-11

Table 4-3. (Continued)
Taxa
2000
2001
2002
2003
2004
2005
2006
2007
2008
Talitrndae
Hyalella azteca
17
95
1,782
121
3,608
1,782
Diptera
Ceratopogonidae
Alluaudomyia spp.
9
Palpomyia-Bezzia complex
17
26
77
9
17
43
34
43
207
Chironomidae-Chironommae
Axarus spp.
9
34
Chironomus spp
9
9
9
Cryptochironmus spp
9
26
103
86
121
Cryptotendipes spp
9
17
26
77
138
706
52
26
34
Dicrotendipes spp
697
Dicrotendipes neomodestus
17
9
189
293
69
224
Glyptotendipes spp
9
Hamischia spp
17
Microchironomus spp
9
Ndothauma spp
9
26
17
Pagashella spp
9
34
86
9
Parachironomus spp
9
9
Polypeddum halterale gp.
9
17
9
9
69
9
Polypeddum d6noense
9
Polypeddum scalaenum
17
26
9
422
Pseudochironomus spp
9
9
34
69
129
17
241
Stempellina spp
17
26
17
Stenochironomus spp
9
9
43
34
60
34
Stictochironomus spp
9
9
Stictoch►ronomus cafframus
17
Tanytarsus spp
26
95
34
258
86
146
Chironomidae-Orthocladnnae
Cncotopus bicinctus
9
Cncotopus pohtus
9
17
9
26
Nanocladius spp
9
Orthocladius spp.
17
Parakieffernella spp.
17
17
26
17
Chironomidae-Tanypodinae
Ablabesmyia spp.
129
86
43
34
103
Ablabesmyo annulata
43
26
9
Ablabesmyojanta
52
17
86
181
276
121
Ablabesmyta mallochi
138
26
9
60
60
34
86
112
224
Coelotanypus spp.
52
17
26
60
121
379
103
9
9
Djalmababsta pulchra
26
9
69
172
Procladius spp.
129
34
17
146
189
241
422
129
241
Procladius bellus
26
4-12

Table 4-3. (Continued)
Taxa
2000
2001
2002
2003
2004
2005
2006
2007
2008
Ephemeroptera
Baetidae
9
Caemdae
Cams spp
9
9
60
34
1,300
Ephemendae
Hexagen►a spp
9
34
9
181
Heptagemidae
Stenacron mterpunctatum
34
9
52
Tricorythidae
Trncorythodes spp
9
Odonata-Anisoptera
Corduludae
Neurocorduha spp
9
Gomphidae
9
9
Dromogomphus spp
9
Odonata-Zygoptera
Coenagrionidae
Argia spp
9
9
Trichoptera
Hydroptdidae
Hydroptda spp
17
9
Orthotnchra spp
9
9
9
Leptocendae
Oecehs spp
9
9
9
17
9
17
69
Tnaenodes spp
9
17
Polycentropodidae
Polycentropus spp
26
17
17
9
138
Coelenterata
Hydroida
Hydridae
Hydra spp
9
Mollusca
Gastropoda
Basommatophora
Physidae
Physella spp
60
26
Limnophda
Ancylidae
Ferrrssia spp
9
Pelecypoda
Heterodontida
Corbiculidae
Corbicula fluminea
1,920
3,685
784
964
603
482
775
387
422
4-13

Table 4-3. (Continued)
Taxa
2000
2001
2002
2003 2004
2005
2006
2007
2008
Nematoda
69
26
52
26
241
60
Nemertea
Enopla
Hoplonemertea
Tetrastemmatidae
Prostoma graecens
172
121
Platyhelminthes
Turbellana
Tncladida
Planamdae
Dugesia spp
258
258
9
155
9
482
448
Total Density for Year
4,385
7,752
2,742
2,895 5,028
4,417
9,196
4,936
6,895
Total Taxa for Year
23
33
28
31 32
27
35
38
31
4-14

12,000
10,000
8,000
U)
am
c
0 6,000
Ca
H
4,000
2,000
2000 2001 2002
i
2003 2004
■B OF G
2005 2006 2007 2008
Figure 4-1. Density (number/M2) of macro invertebrates collected annually during 2000 —
2008 from Mountain Island Lake.
50
45
40
35
a
m
30
0
m 25
x
I�
20
H
15
10
5
0
2000 2001 2002 2003 2004 2005 2006 2007 2008
MB OF G
Figure 4-2. Total number of macro invertebrate taxa collected annually during 2000 — 2008
from Mountain Island Lake.
4-15

10,000
9,000
8,000
7,000
6,000
m
5,000
a�
O
4,000
3,000
2,000
1,000
0
Location B
2000 2001 2002 2003 2004 2005 2006 2007 2008
® Oligochaeta ■ Diptera Corbicula
Figure 4-3. Density (number/m2) of Oligochaeta, Diptera, and Corbacula collected annually
during 2000 — 2008 from Location B in Mountain Island Lake.
6,000
5,000
4,000
m
Z5 3,000
Q
2,000
1,000
0
Location F
2000 2001 2002 2003 2004 2005 2006 2007 2008
■ Oligochaeta ■ Diptera o Corbacula
Figure 4-4. Density (number/M2) of Oligochaeta, Diptera, and Corbacula collected annually
during 2000 — 2008 from Location F in Mountain Island Lake.
4-16

8,000
7,000
6,000
5,000
N
N
c 4,000
m
3,000
2,000
1,000
0
Location G
2000 2001 2002 2003 2004 2005 2006 2007 2008
■ Oligochaeta ■ Diptera Corbicula
Figure 4-5. Density (number/m2) of Oligochaeta, Diptera, and Corblcula collected annually
during 2000 — 2008 from Location G in Mountain Island Lake.
4-17

CHAPTER 5
FISH
MATERIALS AND METHODS
Winter and Summer Electrofishing Surveys
Electrofishing surveys were conducted in Mountain Island Lake near Riverbend Steam
Station (RSS) in January and July (2004 — 2008) uplake from the RSS intake (Location B), in
the discharge canal (Location F), and downlake from the RSS discharge near Mountain
Island Dam (Location G; Table 1-1 and Figure 1-1). The locations surveyed consisted of
100-m transects on both the left and right shorelines. Surface water temperature (°C) and
dissolved oxygen (mg/L) were measured with a calibrated thermistor and dissolved oxygen
probe, respectively, at each location. Stunned fish were collected by two netters, identified
to species, and measured for total length (mm). Catch per unit effort (CPUE, number of
fish/100 m) and the number of species were calculated for each sampling location.
Spring Electrofishing Surveys
Electrofishing surveys were conducted in Mountain Island Lake near RSS in April or May
(2004 — 2008) uplake and downlake from the RSS discharge canal (Figure 1-1). The
locations surveyed were identical to historical locations surveyed since 1993 and consisted of
five 300-m shoreline transects at each location. Transects included habitats representative of
those found in Mountain Island Lake. Shallow flats where the boat could not access within
3-4 in of the shoreline were excluded. All sampling was conducted during daylight, when
water temperatures were expected to be between 15 and 20 °C. Stunned fish were collected
by two netters and identified to species. Fish were enumerated and weighed in aggregate by
taxon, except for largemouth and spotted bass, where total lengths (mm) and weights (g)
were obtained for each individual collected. Surface water temperature (°C) was measured
with a calibrated thermistor at each location. Catch per unit effort (CPUE, number of
fish/1,500 m) and the number of species were calculated for each sampling location.
5-1

Fall Hydroacoustics and Purse Seine Surveys
The abundance and distribution of pelagic forage fish in Mountain Island Lake were
determined using mobile hydroacoustic (Brandt 1996) and purse seine (Hayes et al. 1996)
techniques. An annual mobile hydroacoustic survey from the Mountain Island Dam to
approximately Location C was conducted in mid-September to estimate forage fish
populations (Figure 1-1). Hydroacoustic surveys employed multiplexing, side- and down -
looking transducers to detect surface -oriented fish and deeper fish (from 2.0 in depth to the
bottom), respectively. Both transducers were capable of determining target strength directly
by measuring fish position relative to the acoustic axis.
Purse seine surveys were also collected in mid-September from the forebay of the Mountain
Island Dam (near Location G). The purse seine measured 118 x 9 in, with a mesh size of 4.8
mm. A subsample of forage fish collected from each area was used to estimate taxa
composition and size distribution.
Trace Element Analyses
Selenium, arsenic, mercury, and zinc concentrations were measured in epaxial muscle tissue
of common carp Cyprinus carpio, sunfish (typically redbreast sunfish Lepomis auritus), and
bass (typically largemouth bass Micropterus salmoides) collected by electrofishing in July
(2004 — 2008) at Locations A, B, C, and G (Figure 1-1). Muscle tissue was dissected from
each of five fish from a particular taxon, where available, and trace element concentrations
(µg/g, wet weight) were determined individually by neutron activation analysis at the
Nuclear Services Laboratory at North Carolina State University, Raleigh, NC. Graphical
methods were used to examine spatial and temporal trends in trace element concentrations.
Balanced and Indigenous Assessment
Annual sampling protocols are designed to assess the balanced and indigenous nature of the
Mountain Island Lake fish community and provide information relative to potential RSS
impacts. The assessment includes a comparison of CPUE and number of species data from
locations uplake of, in the discharge canal of, and downlake of RSS during winter and
summer electrofishing. These electrofishing surveys are part of the required RSS 316(a)
annual monitoring program. Additionally, trace element accumulation in fish muscle is
5-2

evaluated in relation to the ash basin discharge. Spring electrofishing and hydroacoustic
surveys near RSS are part of the Catawba-Wateree hydroelectric relicensing activities.
RESULTS AND DISCUSSION
Winter Electrofishing Surveys
Winter electrofishing surveys from 2004 to 2008 produced 5,078 individuals comprising
eight families, 21 species, and two hybrid centrarchid combinations (Table 5-1). The species
composition for the combined winter electrofishing surveys was dominated by clupeids
(47.5%), centrarchids (45.1%), and cyprinids (6.9%), with the remaining families
representing less than 1.0% each. Data from winter 2000 — 2003 documented a lower
percentage of clupeids (5.3%) and cyprinids (2.0%) and a higher percentage of centrarchids
(91.4%; Table 5-1 and Duke Power 2004). Pollution tolerant species (i.e., longnose gar
Lepisosteus osseus, grass carp Ctenopharyngodon Idella, common carp, golden shiner
Notemigonus crysoleucas, white catfish Ameiurus catus, eastern mosquitofish Gambusia
holbrooki, redbreast sunfish, and hybrid sunfish) represented 15.7% of the collected fish
from winter 2004 — 2008. This percentage decreased from 41.6% of collected fish reported
from winter 2000 — 2003.
The CPUE and number of species at individual locations ranged from 41.5 (Location G in
2005) to 701 (Location B in 2006) fish/100 in and from four (Locations F and G in 2005) to
13 species (Location F in 2004), respectively (Figure 5-1, Appendix Tables A-1 to A-5).
Spatial dissimilarities in CPUE (Location B in 2006 and Location F in 2007) and number of
species (Location F in 2004 and 2008) were likely due to collecting schools of threadfin shad
and discharge canal temperature, respectively. Winter electrofishing data are consistent with
previous data (Duke Power 2001, 2004) and indicate no negative impact from RSS
operations on Mountain Island Lake fish populations.
Summer ElectrofishingSays
Summer electrofishing surveys from 2004 to 2008 produced 4,054 individuals comprising
seven families, 17 species, and two hybrid centrarchid combinations (Table 5-2). The
species composition for the combined summer electrofishing surveys was dominated by
centrarchids (66.1%), clupeids (27.5%), and cyprinids (6.2%), with the remaining families
5-3

representing less than 1.0% each. Data from summer 2000 to 2003 documented similar
percentages of each: centrarchids (66.2%), clupeids (30.5%), and cyprinids (2.4%).
Pollution tolerant species represented 30.3% of the collected fish during summer 2004 —
2008. This percentage decreased from 44.1% of collected fish reported from summer 2000 —
2003.
The CPUE and number of species at individual locations ranged from 29.5 (Location G in
2006) to 288.0 (Location F in 2006) fish/100 in and from five to seven species (multiple
locations for each; Figure 5-2, Appendix Tables A-6 to A-10). Spatial dissimilarities were
due to collecting a school of threadfin shad (Location F in 2006) and a large centrarchid
population (Location G in 2007 and 2008). Summer electrofishing data are consistent with
previous data (Duke Power 2001, 2004) and indicate no negative impact from RSS
operations on Mountain Island Lake fish populations.
Suring Electrofishing Surveys
Spring electrofishing surveys from 2004 to 2008 were conducted at water temperatures
ranging from 12.7 to 20.8 °C. Fish numbers and biomass per 1,500 in ranged from 468 to
2,140 and from 45.7 to 131.2 kg, respectively, uplake of the RSS discharge and 706 to 1,389
and 38.4 to 81.6 kg, respectively, downlake from the RSS discharge (Table 5-3). The
number of fish species ranged from 12 to 19 uplake and from 10 to 13 downlake of the RSS
discharge. Previous reports documented that numbers of fish, biomass, and number of
species collected uplake were generally greater than those from downlake locations (Duke
Power Company 1994; Duke Power 2001, 2004). For 2004 — 2008 the numbers of fish and
biomass varied between uplake and downlake, even though the number of species collected
uplake was generally higher. Spring electrofishing surveys, from 2004 to 2008, were
dominated by centrarchids (89.8%) and cyprinids (8.3%), with the remaining families
representing less than 1.0% each (Table 5-4).
Pollution tolerant species represented 28.3% (97.4% of that being redbreast sunfish) of the
collected fish during spring 2004 — 2008. One new species, rainbow trout Oncorhynchus
mykiss, was collected uplake in 2006. Most likely introduced by an angler, it would not be
expected to survive the summer. Spring electrofishing survey data varied among years,
similar to other Catawba River reservoirs.
5-4

Fall Hydroacoustics and Purse Seine Surveys
Similar to Mountain Island Lake and other Catawba River reservoirs since 1994,
hydroacoustics from 2004 to 2008 showed no temporal trend in annual forage fish population
estimates (range = 601,00 — 3,597,000; 603 — 3,611 fish/ha) (Table 5-5). Purse seine surveys
from 2004 to 2008 indicated a shift back to a threadfin shad Dorosoma petenense dominated
(range = 80.2 — 99.8%) forage fish community. Alewife Alosa pseudoharengus, first
detected in low numbers in 1999 (Duke Power 2001), have comprised as much as 83.1%
(2003) of mid-September pelagic, forage fish community surveys, but have remained
relatively low since 2004 (range = 0.2 —19.6%).
Trace Element Analyses
Trace element concentration means for common carp were typically comprised of less than
five fish due to the difficulty of collecting common carp. The four complete common carp
samples (out of 20 attempts; Location A from 2004 to 2006 and Location C in 2005) since
2004 had element concentration means mostly within the ranges of sunfish and bass. An
individual sunfish from Location C in 2005 was a statistical outlier for all trace element
concentrations and not included in analyses. All 2004 — 2008 trace element concentration
means for sunfish and bass decreased at all locations relative to 1993 — 2003 and were within
ranges reported from 1988 to 2003 (Harden and Reid 1991; Duke Power Company 1994;
Duke Power 2001, 2004).
Mean selenium concentrations in fish muscle tissue from complete samples collected from
2004 to 2008 ranged from 0.31 to 1.03 µg/g, wet weight (Figure 5-3). Mean selenium
concentrations since 2004 from sunfish (range = 0.33 — 0.86 µg/g, mean = 0.53 µg/g) and
bass (range = 0.31 — 1.03 µg/g, mean = 0.59 µg/g) were slightly greater than the average
value of 0.50 µg/g measured in largemouth bass muscle tissue from 26 sites throughout the
entire Catawba River basin during 1993 (Coughlan 1995). Location C, downstream from the
ash basin discharge, had the highest mean selenium concentration for three out of the five
years for bass and sunfish, although the years did not coincide between species. All
measured values in common carp, sunfish, and largemouth bass were well below the North
Carolina Department of Health and Human Services (NCDHHS) Action Level of 10.0 µg/g
for the protection of human health (NCDHHS 2007).
5-5

Mean arsenic concentrations in fish muscle tissue from complete samples collected from
2004 to 2008 ranged from 0.03 to 0.17 µg/g, wet weight (Figure 5-4). Mean arsenic
concentrations since 2004 from sunfish (range = 0.03 - 0.17 µg/g, mean = 0.09 µg/g) and
bass (range = 0.04 - 0.17 µg/g, mean = 0.08 gg/g) were similar to the average value of 0.09
gg/g measured in largemouth bass muscle tissue from 26 sites throughout the entire Catawba
River basin during 1993 (Coughlan 1995). All measured values in common carp, sunfish,
and largemouth bass were well below the Division of Water Quality's tissue screening value
of 1.20 µg/g (NCDENR 2006).
Mean mercury concentrations in fish muscle tissue from complete samples collected from
2004 to 2008 ranged from 0.03 to 0.15 µg/g, wet weight (Figure 5-5). Mean mercury
concentrations since 2004 from sunfish (range = 0.04 - 0.13 µg/g, mean = 0.07 µg/g) and
bass (range = 0.06 - 0.15 µg/g, mean = 0.10 µg/g) were similar to the average value of 0.08
µg/g measured in largemouth bass muscle tissue from 26 sites throughout the entire Catawba
River basin during 1993 (Coughlan 1995). All measured values in common carp, sunfish,
and largemouth bass were well below the NCDHHS action level of 0.40 µg/g for the
protection of human health (NCDHHS 2007).
Mean zinc concentrations in fish muscle tissue from complete samples collected from 2004
to 2008 ranged from 2.39 to 8.31 µg/g, wet weight (Figure 5-6). Mean zinc concentrations
since 2004 from sunfish (range = 2.39 - 5.54 µg/g, mean = 4.42 µg/g) and bass (range = 2.43
- 5.63 µg/g, mean = 3.81 µg/g) were below the average value of 6.71 µg/g measured in
largemouth bass muscle tissue from 26 sites throughout the entire Catawba River basin
during 1993 (Coughlan 1995). All measured values in common carp, sunfish, and
largemouth bass were well below concentrations (16 to 82 µg/g) reported for several taxa of
omnivorous freshwater fish from other areas in the United States (Moore and Ramamoorthy
1984).
CONCLUSIONS
A diverse fish community was present in the littoral portions of Mountain Island Lake
around RSS from 2004 to 2008; winter and summer electrofishing surveys documented 21
species (and two hybrid combinations) and 17 species (and two hybrid combinations),
respectively. Both surveys were numerically dominated by clupeids and centrarchids, with
cyprinids also being of numerical importance. Spring electrofishing documented 26 species
5-6

(and one sunfish hybrid combination), dominated by centrarchids and cyprinids. Pollution
tolerant species, mostly redbreast sunfish, comprised 15 — 30% of the Mountain Island Lake
fish community. The assorted fish species typically found in Mountain Island Lake near RSS
encompass a range of trophic groups including insectivores, omnivores, and piscivores.
Forage fish population densities, as measured by hydroacoustics, were variable and ranged
from 603 to 3,611 fish/ha from 2004 to 2008. These densities are comparable to those
measured previously at Mountain Island Lake and to other Catawba River reservoirs of
similar trophic status. The introduction of alewife, the inherent, temporal variability of
clupeid populations, and the historical flux of Mountain Island Lake between oligotrophic
and mesotrophic water quality classifications (Chapter 3) are all factors contributing to the
unpredictable nature of forage fish densities.
Trace element concentrations have been measured in Mountain Island Lake common carp,
sunfish, and bass since 1988. Trace element concentrations from 2004 to 2008 remained
well below values of regulatory concern, where such values exist.
Past studies have indicated that a balanced indigenous fish community exists near the RSS
(Duke Power Company 1994; Duke Power 2001, 2004). The present study adds more years
of comparable data to help reinforce that conclusion. Based on the diversity and numbers of
individuals in the Mountain Island Lake littoral fish community during winter, spring, and
summer; the range of trophic groups represented; the lack of accumulation of selenium,
arsenic, mercury, or zinc in fish flesh; and the regular availability of forage fish to limnetic
predators, it is concluded that the operation of RSS has not impaired the Mountain Island
Lake fish community.
5-7

Table 5-1. Number of individuals and number of species in winter electrofishing surveys
from three locations (B, F, and G) in Mountain Island Lake, 1994 — 1999, 2000
— 2003, and 2004 — 2008.
Winter 1994 - 1999 Winter 2000 - 2003 Winter 2004 - 2008
Scientific Name Common Name No % No % No %
Lepisosteldae
Lepisosteus osseus
Longnose gar
3
011%
8
014%
9
018%
Clupeidae
Dorosoma cepedianum
Gizzard shad
66
234%
12
021%
8
016%
Dorosoma petenense
Threadfin shad
285
507%
2,402
4730%
Cyprinidae
Ctenopharyngodon Idella
Grass carp
1
004%
1
002%
Cypnnella chlonstia
Greenfin shiner
1
002%
Cypnnella nivea
Whdefin shiner
146
518%
29
052%
285
5 61 %
Cypnnus carpio
Common carp
76
270%
24
043%
3
006%
Notemigonus crysoleucas
Golden shiner
3
011%
4
007%
5
010%
Notropis hudsonius
Spottad shiner
6
021%
55
098%
7
014%
Notropis procne
Sw allow tad shiner
49
096%
Catostom idae
Moxostoma collapsum
Notchlip redhorse
1
004%
Ictaluridae
Ameiurus brunneus
Snail bullhead
1
002%
Ictalurus punctatus
Channel catfish
6
0 21 %
18
032%
3
006%
Poeciliidae
Gambusre holbrooki
Eastern mosquitofish
2
007%
7
012%
3
006%
Moronidae
Morone chrysops
White bass
6
0 21 %
2
004%
Morone saxablis
Striped bass
3
0 11 %
11
020%
10
020%
Centrarchidae
Lepomis auntus
Redbreast sunfish
359
1274%
2,290
4077%
764
1505%
Lepomis gibbosus
PUmpkmseed
46
163%
2
004%
4
008%
Lepomis gulosus
Warmouth
24
085%
37
066%
10
020%
Lepomis hybrid
Hybrid sunfish
10
035%
3
005%
9
018%
Lepomis macrochirus
Bluegdl
875
3106%
2138
3806%
1,136
2237%
Lepomis microlophus
Redear sunfish
237
8 41 %
333
593%
164
323%
Micropterus punctulatus
Spotted bass
3
006%
Micropterus salmoides
Largemouth bass
905
3213%
313
557%
185
364%
Micropterus hybrid
Hybrid black bass
5
010%
Pomoxis annulans
White crappie
1
004%
Pomoxis mgromaculatus
Black crappie
37
1 31%
19
034%
11
022%
Percidae
Etheostoma fustforme
Sw amp darter
1
004%
Etheostoma olmstedi
Tessellated darter
2
007%
10
018%
Perca flavescens
Yellow perch
1
004%
15
027%
2
004%
Total No. Individuals
2,817
100.00%
5,617
100.00%
5,078
100.00%
Total No. Species
23
22
21
5-8

Table 5-2. Number of individuals and number of species in summer electrofishing surveys
from three locations (B, F, and G) in Mountain Island Lake, 1991 —1993, 1994 —
1999, 2000 — 2003, and 2004 — 2008.
5-9
Sumner 1991 - 1993
Sumner 1994 - 1999
Sumner 2000 - 2003
Sumner 2004 - 2008
Scientific Narre
Conrrhon Name
No
%
No
%
No
%
No
%
Lepisosterdae
Leprsosteus osseus
Longnose gar
3
0 08 %
3
008%
2
0 05 %
Clupeidae
Alosapseudoharengus
Alewife
1
003%
Dorosoma cepedianum
Gizzard shad
3
1 17%
11
029%
1
003%
4
0 10 %
Dorosomapetenense
Threadfin shad
933
2482%
1,163
3045%
1,111
2741%
Cypnmdae
Ctenopharyngodon rdella
Grass carp
3
0 08 %
2
005%
Cypnnellanrvea
Whdefnshner
6
233%
80
213%
85
223%
250
617%
Cypnnus carpro
Cannon carp
13
506%
29
077%
2
0 05 %
1
0 02 %
Hybognathus regius
Eastern silvery mnnow
1
0 03 %
Notemrgonus crysoleucas
Golden shiner
2
005%
Notroprs hudsonrus
Spottail shiner
24
064
Catostomrdae
Carprodes cypnnus
Qwllback
7
272%
Moxostoma collapsum
Notchlip redhorse
1
039%
Ictalurrdae
Amerurus catus
Wide catfish
2
078%
11
0 29 %
1
0 03 %
Amerurus platycephalus
Flat bullhead
1
039%
2
005%
Ictalurus furcatus
Blue catfish
1
003%
Ictalurus punctatus
Channel catfish
1
0 39 %
7
019%
1
002%
Pyfodichs olrvans
Flathead catfish
1
003%
1
0 03 %
1
0 02 %
Moronidae
Moron saxabhs
Striped bass
1
002%
Centrarchrdae
Lepomrsauntus
Redbreast sunfish
87
3385%
1,776
4725%
1,672
4377%
1,213
2992%
Lepomrs gibbosus
FLrrpknseed
6
016%
Lepomrs gulosus
Warmouth
1
039%
13
035%
16
042%
18
044%
Lepomrs hybrid
Hybrid sunfish
2
0 78 %
3
008%
5
013%
12
0 30 %
Lepomrs macrochrrus
Bluegdl
45
17 51 %
408
1085%
486
12 72 %
1,048
2585%
Lepomrs mrcrolophus
Redear sunfish
25
973%
27
072%
94
246%
116
2 86 %
Micropterus punctulatus
Spotted bass
3
007%
Micropterus salmoides
Largemouth bass
58
2257%
383
1019%
254
665%
262
646%
Micropterus hybrid
Hybrid black bass
4
010%
Pomows annularis
Wide crappie
3
1 17%
Pomoxrs nrgromaculatus
Black crappie
2
0 78 %
22
059%
1
0 03 %
2
0 05 %
Percrdae
Etheostoma olmstedi
Tessellated darter
4
010%
3
007%
Perca flavescens
Yellow perch
17
045%
27
0 71 %
Total No. Individuals
257
100.00%
3,759
100 00 %
3,820
100 00 %
4,064
100 00 %
Total No. Species
1s
20
18
17
5-9

Table 5-3. Number of individuals, biomass, and number of species collected during spring electrofishing of five 300-m transects
downlake and five 300-m transects uplake of the RSS discharge canal in Mountain Island Lake, 1993 — 1997, 1999 —
2008.
Year
_
1993
1994
1995
1996
1997
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
Average
Uplake
Total No Indimduals
475
454
355
854
412
843
1,273
1,769
1,862
2,123
955
1,292
468
1,009
2,140
1,086
Biomass (kg)
13418
81 19
12039
95 58
9843
5736
4889
75 58
51 98
5833
64 93
5827
4568
78 22
131 23
80.02
Total No Species
15
16
10
13
11
14
14
14
13
15
15
14
12
13
19
14
Downlake
Total No Indimduals
307
388
368
356
519
590
874
1,437
1,140
1,434
1,263
706
1,278
1,389
1,379
895
Biomass (kg)
58 36
8267
4757
7198
35 94
29 12
5623
51 30
3578
4990
38 42
81 61
5336
57 95
69 55
54.65
Total No Species
12
12
10
10
12
9
16
11
10
14
12
13
12
11
10
12

Table 5-4. Number of individuals and number of species collected during spring
electrofishing of ten 300-m transects in the vicinity of the RSS discharge
canal in Mountain Island Lake, 1994 —1997 and 1999, 2000 — 2003, and 2004
—2008.
1994 - 1997, 1999 2000-2003 2004-2008
Scientific Name Common Name No oda No % No oda
Lepisosteidae
Leptsosteus osseus
Longnose gar
2
004%
3
003%
2
002%
Clupeidae
Alosa pseudoharengus
Alew ite
8
007%
Dorosoma cepedianum
Gizzard shad
91
177%
32
027%
46
039%
Dorosoma petenense
Threadfin shad
1
002%
22
019%
Cyprinidae
Ctenopharyngodon Idella
Grass carp
3
003%
9
008%
Cypnnella chlorrstia
Greenfin shiner
13
025%
23
019%
5
004%
Cyprnnella nuvea
Whitefin shiner
130
253%
354
297%
929
782%
Cyprnnus carpuo
Common carp
70
136%
17
014%
32
027%
Nocomis leptocephalus
Bluehead chub
1
0 01 %
Notemigonus crysoleucas
Golden shiner
2
004%
8
007%
3
003%
Notropus hudsonius
Spottad shiner
20
039%
23
019%
1
0 01 %
Notropis procne
Sw allow tad shiner
3
006%
3
003%
8
007%
Catostom idae
Carptodes cyprnnus
Qwllback
1
002%
2
002%
Moxostoma collapsum
Notchlip redhorse
2
004%
Ictaluridae
Ameiurus catus
White catfish
1
002%
1
001%
lctalurus punctatus
Channel catfish
14
027%
16
013%
25
021%
Salmon idae
Oncorhynchus mykiss
Rainbow trout
1
0 01 %
Poeciliidae
Gambusia holbrooki
Eastern mosquitofish
4
003%
4
003%
Moronidae
Morone americana
White perch
1
0 01 %
14
012%
Morone chrysops
White bass
2
004%
Centrarchidae
Lepomis auntus
Redbreast sunfish
2,269
4415%
3,602
3024%
3,272
2754%
Lepomis glbbosus
Pumpkinseed
7
014%
1
001%
Lepomis gulosus
Warmouth
42
082%
82
069%
53
045%
Lepomis hybrid
Ffybril sunfish
17
033%
22
018%
39
033%
Lepomis macrochirus
Bluegdl
741
1442%
5,678
4767%
5,193
4372%
Lepomis mucrolophus
Redear sunfish
145
282%
1,257
1055%
1,357
1142%
Micropterus punctulatus
Spotted bass
2
002%
Micropterus salmoides
Largemouth bass
1,435
2792%
725
609%
726
611%
Pomoxis nugromaculatus
Black crappie
3
006%
14
012%
22
0.19%
Percidae
Etheostoma fustforme
Sw amp darter
1
002%
1
0 01 %
Etheostoma olmstedi
Tessellated darter
1
002%
2
002%
12
010%
Perca flavescens
Yellow perch
126
245%
39
033%
92
077%
Total No. Individuals
5,139
100.00%
11,912
100.00%
11,879
100.00%
Total No. Species
24
23
26
5-11

Table 5-5. Number, percentage, average length, average density, and forage fish population estimates in Mountain Island Lake, 1993
— 1997, 1999 — 2008, from mid-September purse seine and hydroacoustic surveys.
Year (Purse seine collection date)
1994
1996
1996
1997
1999
2000
2001 2002
2003
2004
2006
2006
2007
2008
Species
(9/21)
(7120)
(9/18)
(10/16)
(9/22)
(9/19)
(9/12) (9123)
(9115)
(9/13)
(9/19)
(9/19)
(9/13)
(9110)
Threadfin shad
Number
580
825
1,169
182
570
1,984
1,580 3,336
656
522
3,970
4,450
9,275
5,963
Percentage
9949
81 93
99 57
10000
9948
83 28
89 29 9010
1692
8021
95 84
8712
9976
9586
Average length (mm)
538
41 9
501
59 2
54 0
530
51 7 438
58 2
51 9
523
51 9
52 2
54 8
Gizzard shad
Number
3
182
5
2
Percentage
0 51
18 07
043
027
Average length (mm)
773
72 4
76 4
840
Alewife
Number
3
398
190 366
3,220
127
172
659
22
257
Percentage
052
1672
10 71 9 89
8309
1958
4 15
1289
024
414
Average length (mm)
720
748
61 6 65 6
671
678
65 7
639
560
61 3
Hydroacoustic Data
Density
(No1ha)
3,867
4,312
6,798
998
4,413
2,530
4,554 3,752
2,366
603
3,611
2,952
2,836
2,268
Population estimate
3,852,000
4,295,000
6,771,000
994,000
4,395,000
2,520,000
4,536,000 3,737,000
2,357,000
601,000
3,597,000
2,940,000
2,825,000
2,259,000

800
700
600
E
0 500
U)
Z 400
0
z
300
200
100
0
1994
16
14
12
E
0 10
U)
8
U
N
CL
fA
0 6
Z
4
2
0
1994
1996 1998 2000 2002 2004 2006 2008
1996 1998 2000 2002 2004 2006 2008
Figure 5-1. Number of fish (a), and fish species (b) collected from electrofishing a 100-m
transect at each of three locations (B, F, and G) during winter electrofishing in
Mountain Island Lake, 1994 — 2008.
5-13

800
700
600
E
0 500
s
w 400
0
z
300
200
100
0
16
14
12
E
0 10
U 8
N
CL
(0 6
0
z
4
2
0
1994 1996 1998 2000 2002 2004 2006 2008
b X B -*- F -A G
1994 1996 1998 2000 2002 2004 2006 2008
Figure 5-2. Number of fish (a), and fish species (b) collected from electrofishing a 100-m
transect at each of three locations (B, F, and G) during summer electrofishing in
Mountain Island Lake, 1994 — 2008.
5-14

16
14
12
10
rn
3 08
a�
U) 06
04
02
00
1994
a
X A -I-- B1�i C --e- G
16
14
12
a' 1 0
rn
m
08
U) 06
04
02
00
1994
■
1996 1998 2000 2002 2004 2006 2008
b -XA tB 6 C -G-G
1996 1998 2000 2002 2004 2006 2008
16
14 C
12
°1 1 0
rn
a�
08
0.6
04
02
00
1994 1996 1998 2000 2002 2004 2006 2008
Figure 5-3. Selenium concentrations in muscle tissue from common carp (a), sunfish (b), and
bass (c) from four locations (A, B, C, and G) in Mountain Island Lake, 1994 —
2008. The only complete common carp samples were Locations A (2004 —
2006) and C (2005).
5-15

05
a
04
03
02 ■ ■
01
00
1994 1996 1998 2000 2002 2004 2006 2008
05
04
03
CO
02
01
00
1994
b X A tB AC -e-G
05
04
03
z
02
01
00
1996 1998 2000 2002 2004 2006 2008
1994 1996 1998 2000 2002 2004 2006 2008
Figure 5-4. Arsenic concentrations in muscle tissue from common carp (a), sunfish (b), and
bass (c) from four locations (A, B, C, and G) in Mountain Island Lake, 1994 —
2008. The only complete common carp samples were Locations A (2004 —
2006) and C (2005).
5-16

06
05
rn 04
rn
03
02
01
00
1995
06
05
a,
04
rn
3 03
02
01
00
1995
1997 1999 2001 2003 2005 2007
b - A t B -A C ---- G
1997 1999 2001 2003 2005 2007
06
C
0.5
o,
04
3 03
rn
02
01
00
1995 1997 1999 2001 2003 2005 2007
Figure 5-5. Mercury concentrations in muscle tissue from common carp (a), sunfish (b), and
bass (c) from four locations (A, B, C, and G) in Mountain Island Lake, 1995 —
2008. The only complete common carp samples were Locations A (2004 —
2006) and C (2005).
5-17

120
100
a,
80
rn
60
N
40
20
00
1997
120
100
o,
80
rn
60
N
40
2.0
00
1997
X
1999 2001 2003 2005 2007
X A t A C -e-G
1999 2001 2003 2005 2007
120
C
100
a,
80
rn
z
60
N
40
20
00
1997 1999 2001 2003 2005 2007
Figure 5-6. Zinc concentrations in muscle tissue from common carp (a), sunfish (b), and
bass (c) from four locations (A, B, C, and G) in Mountain Island Lake, 1997 —
2008. The only complete common carp samples were Locations A (2004 —
2006) and C (2005).
5-18

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L-1

Hayes, DB, CP Ferrier, and WW Taylor. 1996. Active fish capture methods. Pages 193-220
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County, NC.
NCDENR. 2006. Standard operating procedures. Fish tissue assessments. NCDENR,
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Code 15A NCAC 02B .0100, .0200 & .0300, Amended effective May 1, 2007.
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(2006 Integrated 305(b) and 303(d) Report), approved May 17, 2007. NCDENR,
Division of Water Quality. Raleigh, NC.
NCDENR. 2009. Division of Water Resources: Drought Monitoring. Web site:
http://www.ncwater.ora/Drought Monitoring/ (Accessed May 17, 2009).
National Oceanic and Atmospheric Administration (NOAA). 2008a. 2007 Local
climatological data: Annual summary with comparative data, Charlotte, North
Carolina (KCLT). U.S. Department of Commerce, National Climatic Data Center,
Asheville, NC.
NOAA. 2008b. August 2008 local climatological data: Charlotte, NC. U.S. Department of
Commerce, National Climatic Data Center, Asheville, NC.
L-2

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Cary, NC.
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Protection Agency National Eutrophication Survey. Report on Mountain Island
Lake, Gaston and Mecklenburg Counties, North Carolina, EPA Region IV, Working
Paper No. 386. Pacific Northwest Environmental Research Laboratory, Las Vegas,
NV. 15 pp.
USEPA. 1976. Quality criteria for water. ("Red Book"). PB -263 943. USEPA,
Washington, DC.
USEPA. 1977. Interagency 316(a) technical guidance manual and guide for thermal effects
sections of nuclear facilities environmental impact statements. Draft May 1, 1977.
USEPA Office of Water Enforcement, Washington, DC.
USEPA. 1983. Methods for the Chemical Analysis of Water and Wastes. Environmental
Monitoring and Support Lab, Office of Research and Development. Cincinnati, OH.
USEPA. 1994. Methods for the Determination of Metals in Environmental Samples.
Supplement I. EPA/600/R-94/111. Office of Research and Development,
Washington, DC.
USEPA. 2003. Response of surface water chemistry to the Clean Air Act Amendments of
1990. EPA/620/R-03/001. Office of Research and Development, Research Triangle
Park, NC.
Warby, RAF, CE Johnson, and CT Driscoll. 2008. Changes in aluminum concentrations and
speciation in lakes across the northeastern U.S. following reductions in acidic
deposition. Environ Sci Techno142(23): 8668-8674.
Weiss, CM, and EJ Kuenzler. 1976. The trophic state of North Carolina lakes. Research
Report No. 119. Water Resources Research Institute, University of North Carolina.
Raleigh, NC. 224 p.
L-3

APPENDIX TABLES
Appendix Table A-1. Species composition, number of individuals, catch per unit effort
(No./100 m), number of species, temperature, and dissolved oxygen
concentration at three electrofishing locations (B, F, and G) in
Mountain Island Lake, January 22, 2004.
Locations
B F G Total
Saentdic Name Common Name No No No No %
Le pis oste idae
Lepisosteus osseus
Longnose gar
5
1
6
067%
Clupeidae
Dorosoma cepedianum
Gizzard shad
2
2
022%
Dorosoma petenense
Threadfin shad
441
441
4895%
Cyprinidae
Cypnnella rnvea
Whitefin shiner
32
32
355%
Cypnnus carpio
Common carp
1
1
0 11 %
Notemigonus crysoleucas
Golden shiner
1
1
2
022%
Poeciliidae
Gambusia holbrooki
Eastern mosgwtofish
1
1
011%
Moronidae
Morone saxatilis
Striped bass
2
2
022%
Ce ntrarch idae
Lepomis auntus
Redbreast sunfish
58
8
27
93
1032%
Lepomis gulosus
Warmouth
1
2
3
033%
Lepomis hybrid
Hybrid sunfish
1
1
011%
Lepomis macrochirus
Bluegill
58
26
135
219
24 31 %
Lepomis microlophus
Redear sunfish
21
9
3
33
366%
Micropterus salmoides
Largemouth bass
16
38
2
56
622%
Pomoxis mgromaculatus
Black crappie
8
8
089%
Pe rcidae
Perca flavescens
Yellow perch
1
1
0 11 %
Total No. Individuals
156
574
171
901
10000%
CPUE (No. fish/100 m)
780
2870
855
1502
Total No. Species
6
13
7
15
Water Temperature (' C)
100
181
100
Dissolved Oxygen (mg/L)
105
100
106
A-1

Appendix Table A-2. Species composition, number of individuals, catch per unit effort
(No./100 m), number of species, temperature, and dissolved oxygen
concentration at three electrofishing locations (B, F, and G) in
Mountain Island Lake, January 12, 2005.
Locations
B
F
G
Total
Scientific Name
Common Name
No
No
No.
No
%
Cyprinidae
Cyprrnella mvea
Whitefin shiner
46
46
1559%
Notropis hudson►us
Spottad shiner
3
3
102%
Centrarchidae
Lepomis auntus
Redbreast sunfish
12
18
36
66
2237%
Lepomis hybrid
Hybrid sunfish
2
2
068%
Lepomis macrochirus
Bluegdl
18
42
33
93
3153%
Lepomis microlophus
Redear sunfish
33
8
3
44
1492%
Micropterus salmoides
Largemouth bass
9
21
11
41
1390%
Total No. Individuals
121
91
83
295 10000%
CPUE(No. fish/100 m)
605
455
415
492
Total No. Species
6
4
4
6
Water Temperature (° C)
118
127
122
Dissolved Oxygen (mg/L)
9 9
9 9
103
A-2

Appendix Table A-3. Species composition, number of individuals, catch per unit effort
(No./100 m), number of species, temperature, and dissolved oxygen
concentration at three electrofishing locations (B, F, and G) in
Mountain Island Lake, January 12, 2006.
Locations
B F G Total
Scientific Name Common Name No No No No %
Leplsosteidae
Lepisosteus osseus
Longnose gar
1
1
006%
Clupeidae
Dorosoma ceped►anum
Gizzard shad
2
2
012%
Dorosoma petenense
Threadfin shad
1,373
5
1,378
8402%
Cyprinidae
Cypnnella mvea
Whdefin shiner
13
13
079%
Cyprmus Carpio
Common carp
1
1
006%
Notemigonus crysoleucas
Golden shiner
2
2
012%
Centrarchidae
Lepomis aurntus
Redbreast sunfish
9
20
39
68
415%
Lepomis gulosus
Warmouth
1
2
3
018%
Lepomis hybrid
Hybrid sunfish
1
1
006%
Lepomis macrochirus
Bluegdl
10
47
72
129
787%
Lepomis microlophus
Redear sunfish
3
13
9
25
152%
Micropterus punctulatus
Spotted bass
1
1
006%
Micropterus salmoides
Largemouth bass
3
8
5
16
098%
Total No. Individuals
1,402
93
145
1,640 10000%
CPIE(No. fish/100 m)
701
465
725
2733
Total No. Species
8
7
7
12
Water Temperature (° C)
107
117
116
Dissolved Oxygen (mg/L)
101
99
100
A-3

Appendix Table A-4. Species composition, number of individuals, catch per unit effort
(No./100 m), number of species, temperature, and dissolved oxygen
concentration at three electrofishing locations (B, F, and G) in
Mountain Island Lake, January 3, 2007.
Locations
B
F
G
Total
Scientific Name
Common Name
No
No
No
No
%
Le pis oste idae
Leptsosteus osseus
Longnose gar
2
2
016%
Clupeidae
Dorosoma cepedianum
Gizzard shad
1
2
3
024%
Dorosoma petenense
Threadfin shad
582
582
4652%
Cyprinidae
Cypnnella mvea
Whitefin shiner
77
2
18
97
775%
Moronidae
Morone saxahlis
Striped bass
1
1
008%
Centrarchidae
Lepomis auntus
Redbreast sunfish
19
29
148
196
1567%
Lepomis gulosus
Warmouth
4
4
032%
Lepomis hybrid
Hybrid sunfish
1
1
2
016%
Lepomis macrochirus
Bluegill
17
77
167
261
2086%
Lepomis microlophus
Redear sunfish
2
5
41
48
384%
Micropterus salmoides
Largemouth bass
13
29
8
50
400%
Micropterus hybrid
Hybrid black bass
1
3
4
032%
Pomoxis nigromaculatus
Black crappie
1
1
008%
Total No. Individuals
129
730
392
1,251
10000%
CPUE(No. fish/100 m)
64 5
365
196
2085
Total No. Species
6
10
8
12
Wate r Te m pe ratu re (' C)
132
176
141
Dissolved Oxygen (mg/L)
8 9
8 9
8 9
A-4

Appendix Table A-5. Species composition, number of individuals, catch per unit effort
(No./100 m), number of species, temperature, and dissolved oxygen
concentration at three • electrofishing locations (B, F, and G) in
Mountain Island Lake, January 3, 2008.
Locations
B F G Total
Scientific Name Cominon Name No No. No No %
Clupeidae
Dorosoma cepedianum
Gizzard shad
1
1
010%
Dorosoma petenense
Threadfin shad
1
1
010%
Cyprinidae
Ctenopharyngodon Idella
Grass carp
1
1
010%
Cyprnnella mvea
Whitefin shiner
95
2
97
979%
Cypnnus carpio
Common carp
1
1
010%
Notemigonus crysoleucas
Golden shiner
1
1
010%
Notropis hudsomus
Spottad shiner
4
4
040%
Notropis procne
Swallow tad shiner
49
49
494%
Ictaluridae
lctalurus punctatus
Channel catfish
3
3
030%
Poeciliidae
Gambusia holbrooki
Eastern mosgwtofish
1
1
2
020%
Moronidae
Morone saxatihs
Striped bass
7
7
0 71 %
Centrarchidae
Lepomis auntus
Redbreast sunfish
149
109
83
341
34 41 %
Lepomis g►bbosus
Pumpkinseed
4
4
040%
Lepomis hybrid
Hybrid sunfish
3
3
030%
Lepomis macrochirus
Bluegdl
177
85
172
434
4379%
Lepomis microlophus
Redear sunfish
7
3
4
14
141%
Micropterus punctulatus
Spotted bass
2
2
020%
Micropterus salmoides
Largemouth bass
7
7
8
22
222%
Micropterus hybrid
Hybrid black bass
1
1
010%
Pomoxis mgromaculatus
Black crappie
2
2
020%
Percidae
Perca flavescens
Yellow perch
1
1
010%
Total No. Individuals
490
226
275
991
10000%
CPUE(No. fish/100 m)
245
113
1375
1652
Total No. Species
9
12
8
19
Water Temperature (" C)
76
176
106
Dissolved Oxygen (mg/L)
11 0
107
107
A-5

Appendix Table A-6. Species composition, number of individuals, catch per unit effort
(No./100 m), number of species, temperature, and dissolved oxygen
concentration at three electrofishing locations (B, F, and G) in
Mountain Island Lake, July 8, 2004.
Total No. Individuals
252
Locations
318 663 10000%
CPIJE (No. fish/100 m)
1260
465
1590 1105
B
F
G
Total
Scientific Name
Conmon Name
No
No
No
No
%
Cyprinidae
Ctenopharyngodon idella
Grass carp
1
1
015%
Cypnnella mvea
Whitefin shiner
23
11
1
35
528%
Ce ntrarchidae
Lepomis aurntus
Redbreast sunfish
123
15
188
326
4917%
Lepomis gulosus
Warmouth
2
6
8
1 21 %
Lepomis hybrid
Hybrid sunfish
2
1
3
045%
Lepomis macrochirus
Bluegdl
61
36
82
179
2700%
Lepomis microlophus
Redear sunfish
23
1
10
34
513%
Micropterus punctulatus
Spotted bass
1
1
015%
Micropterus salmoides
Largemouth bass
17
28
29
74
1116%
Percidae
Etheostoma olmstedi
Tessellated darter
1
1
2
030%
Total No. Individuals
252
93
318 663 10000%
CPIJE (No. fish/100 m)
1260
465
1590 1105
Total No. Species
7
7
7 9
Water Temperature (° C)
272
330
316
Dissolved Oxygen (mg/L)
55
64
72
A-6

Appendix Table A-7. Species composition, number of individuals, catch per unit effort
(No./100 m), number of species, temperature, and dissolved oxygen
concentration at three electrofishing locations (B, F, and G) in
Mountain Island Lake, July 5, 2005.
Scientific Name
Common Name
Locations
B F
No No
G
No
Total
No %
Clupeidae
405
1155 822
Total No. Species
7
5
7 10
Dorosoma cepedianum
Gizzard shad
346
301
1
1
020%
Cyprinidae
Ctenopharyngodon Idella
Grass carp
1
1
020%
Cypnnella nivea
Whitefm shiner
27
6
3
36
730%
Ictaluridae
Pylodictis olivaris
Flathead catfish
1
1
020%
Centrarchidae
Lepomis auntus
Redbreast sunfish
95
21
117
233
4726%
Lepomis gulosus
Warmouth
2
2
0 41 %
Lepomis hybrid
Hybrid sunfish
2
2
041%
Lepomis macrochirus
Bluegdl
37
24
95
156
3164%
Lepomis microlophus
Redear sunfish
3
7
10
203%
Micropterus salmoides
Largemouth bass
17
29
4
50
1014%
Pomoxis nigromaculatus
Black crappie
1
1
020%
Total No. Individuals
181
81
231 493 10000%
CPUE(No. fish/100 m)
905
405
1155 822
Total No. Species
7
5
7 10
Water Temperature (° C)
272
346
301
Dissolved Oxygen (mg/L)
61
62
71
A-7

Appendix Table A-8.
Species composition, number of individuals, catch per unit effort
(No./100 m), number of species, temperature, and
dissolved oxygen
concentration at three
electrofishing locations
(B, F, and G) in
Mountain Island Lake, July 25, 2006.
Locations
B F
G
Total
Scientific Name
Common Name
No No
No
No %
Clupeldae
Dorosoma petenense
Threadfm shad
525
4
529 7007%
Cyprinidae
Cypnnella mvea
Whitefin shiner
1 14
1
16 212%
Centrarchidae
Lepomis auntus
Redbreast sunfish
50 5
31
86 1139%
Lepomis gulosus
Warmouth
1
1 013%
Lepomis hybrid
Hybrid sunfish
1
1 013%
Lepomis macrochirus
Bluegdl
46 24
14
84 11 13%
Lepomis microlophus
Redear sunfish
6
5
11 146%
Micropterus salmoides
Largemouth bass
16 8
3
27 358%
Total No. Individuals
120 576
59
755 10000%
CPUE (No. fish/100 m)
600 2880
29 5
1258
Total No. Species
5 5
7
7
Water Temperature (` C)
302 352
322
Dissolved Oxygen (mg/L)
6 5 6 8
7 3
A-8

Appendix Table A-9. Species composition, number of individuals, catch per unit effort
(No./100 m), number of species, temperature, and dissolved oxygen
concentration at three electrofishing locations (B, F, and G) in
Mountain Island Lake, July 11, 2007.
Locations
B
F
G
Total
Scientific Name
Common Name
No
No
No
No
%
Clupeidae
Dorosoma cepedianum
Gizzard shad
2
2
0 31 %
Cyprinidae
Ctenopharyngodon Idella
Grass carp
2
2
0 31 %
Cypnnella nivea
Whitefin shiner
15
34
3
52
813%
Centrarchidae
Lepomis auntus
Redbreast sunfish
71
18
242
331
5172%
Lepomts gibbosus
Pumpkinseed
Lepomis gulosus
Warmouth
10
10
156%
Lepomis hybrid
Hybrid sunfish
1
1
016%
Lepomis macrochirus
Bluegdl
44
32
119
195
3047%
Lepomis microlophus
Redear sunfish
7
4
17
28
438%
Micropterus punctulatus
Spotted bass
1
1
016%
Micropterus salmoides
Largemouth bass
3
8
7
18
2 81 %
Total No. Individuals
142
98
400
640 10000%
CPUE(No. fish/100 m)
71 0
49 0
2000
1067
Total No. Species
6
6
7
9
Water Temperature (° C)
29 0
337
309
Dissolved Oxygen (mg/L)
6 5
6 4
7 3
A-9

Appendix Table A-10. Species composition, number of individuals, catch per unit effort
(No./100 m), number of species, temperature, and dissolved
oxygen concentration at three electrofishing locations (B, F, and
G) in Mountain Island Lake, July 29, 2008.
Locations
B F G Total
Scientific Name
Conrnon Name
No
No
No
No
%
Cyprinidae
Cyprnnella mvea
Whitefin shiner
4
58
4
66
740%
Cypnnus carpio
Common carp
1
1
011%
Ictaluridae
Ictalurus punctatus
Channel catfish
1
1
011%
Centrarchidae
Lepomis auntus
Redbreast sunfish
89
28
255
372
4170%
Lepomis gulosus
Warmouth
3
3
034%
Lepomis hybrid
Hybrid sunfish
2
2
4
045%
Lepomis macrochirus
Bluegdl
56
141
171
368
4126%
Lepomts microlophus
Redear sunfish
5
8
13
146%
Micropterus punctulatus
Spotted bass
2
2
022%
Micropterus salmoides
Largemouth bass
39
4
18
61
684%
Percidae
Etheostoma olmstedi
Tessellated darter
1
1
011%
Total No. Individuals
195
234
463
892 10000%
CPUE(No. fish/100 m)
975
117
2315
1487
Total No. Species
7
5
7
10
Water Temperature (" C)
301
357
327
Dissolved Oxygen (mg/L)
78
76
76
A-10